tretinoin and Mouth-Neoplasms

Fanconi's anaemia is a rare genetic disorder and majority of the patients die of haematologic complications in their second or third decades of life. Others who have mild or no cytopenias survive long enough to develop malignancies. This is a report of a 44-year-old woman who presented with recurrent oral squamous cell carcinoma during her adulthood, without clinical haematological problem. Despite treatment with cis-retinoic acid, she developed a third squamous cell carcinoma 6 months later. In a review of the literature, only in 1 reported case was the patient treated with low-dose retinoids but he developed recurrent anal cancer after 14 months.

Topics: Adolescent; Adult; Animals; Antineoplastic Agents; Carcinoma, Squamous Cell; Child; Dogs; Fanconi Anemia; Female; Humans; Mouth Neoplasms; Neoplasm Recurrence, Local; Prognosis; Reoperation; Survival Rate; Tretinoin

Chemoprevention is the newest strategy for controlling and managing cancer. At present, the multistep character of epithelial carcinogenesis makes this disease process the most amendable to chemopreventive interventions, which occur in the postinitiation, preinvasive phases. Chemoprevention study has focused on oral carcinogenesis because of its excellent preclinical models, well-defined premalignant phase (leukoplakia), ease of monitoring, and link through field carcinogenesis to other epithelial carcinogeneses of the upper and lower aerodigestive tract. Retinoids, the derivatives of vitamin A, are the most-studied chemopreventive agents, and 13-cis-retinoic acid is the best-studied chemopreventive retinoid. Laboratory study of the newly discovered nuclear receptors of retinoic acid is closing in on the precise mechanism of retinoid action. Only 13-cis-retinoic acid, at high doses, has established chemopreventive activity, which is in suppressing oral premalignancy and preventing second primary head-and-neck tumors. Preclinical and clinical work in the other aerodigestive sites of the lung and esophagus are at an early phase of study with no conclusive results currently available. High-dose 13-cis-retinoic acid also has achieved significant activity in preventing invasive carcinomas of the skin. High-dose 13-cis-retinoic acid, however, is not ideal for widespread chemoprevention approaches because of its toxicity. The toxicity-to-risk balance is delicate and complicated.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Esophageal Neoplasms; Humans; Lung Neoplasms; Mouth Neoplasms; Tretinoin

Liarozole is a 1-substituted imidazole derivative that inhibits cytochrome P450 activity and increases endogenous plasma concentrations of retinoid acid (RA). We have previously demonstrated that RA down-modulates transforming growth factor (TGF)-alpha and epidermal growth factor receptor (EGFR) levels in head and neck squamous cell carcinoma by decreasing the transcription rate of these two genes. Previous reports suggest that RA receptor (RAR)-beta levels are down-modulated in head and neck cancer and are restored by RA therapy. Cellular RA-binding protein (CRABP)-II is up-regulated by RA and appears to modulate intracellular RA metabolism. In conjunction with a Phase I clinical trial, total intact RNA was extracted from oral cavity mucosa biopsied from 17 patients with advanced malignancies, before and after treatment with a 4-week course of liarozole. To analyze these limited quantities of total RNA (as little as 0.6 microg/sample), a quantitative reverse transcription-PCR assay was developed using delayed dropping of the 5' beta-actin primer to amplify the highly abundant beta-actin gene as an internal control. We used this method to determine the expression levels of TGF-alpha, EGFR, RAR-beta, and CRABP-II before and after treatment. There was a trend toward elevation of RAR-beta levels in oral mucosa after liarozole therapy (P = 0.107), whereas TGF-alpha, EGFR, and CRABP-II were not modulated by systemic liarozole treatment. These results suggest that liarozole may up-regulate RAR-beta in tissues from cancer patients and that expression levels of potential intermediate biomarkers may be determined in small tissue biopsies using a quantitative reverse transcription-PCR assay.

Topics: Actins; Antineoplastic Agents, Hormonal; Biomarkers; Carcinoma, Squamous Cell; DNA Primers; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; ErbB Receptors; Humans; Imidazoles; Mouth Mucosa; Mouth Neoplasms; Receptors, Retinoic Acid; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor alpha; Tretinoin; Up-Regulation

Epigenetic silencing of retinoic acid (RA) signaling-related genes have been linked with the pathogenesis and clinical outcome in oral squamous cell carcinoma (OSCC) carcinogenesis. However, the precise mechanisms underlying the abnormal silencing of RA signaling-related genes in OSCC have not been well investigated.. Using combined analysis of genome-wide gene expression and methylation profile from 40 matched normal-tumor pairs of OSCC specimens, we found a set of retinoid signaling related genes are frequently hypermethylated and downregulated in OSCC patient samples, including alcohol dehydrogenase, iron containing 1 (ADHFE1) and aldehyde dehydrogenase 1 family, member A2 (ALDH1A2), which are the important rate-limiting enzymes in synthesis of RA. The expression of ADHFE1 and ALDH1A2 in OSCC patients was determine by quantitative real-time PCR (qRT-PCR) and immunohistochemistry. The binding sites of miR-30a and miR-379 with DNA methyltransferase 3B (DNMT3B) were predicted using a series of bioinformatic tools, and validated using dual luciferase assay and Western blot analyses. The functions of miR-30a, miR-379, and DNMT3B were accessed by growth and colony formation analyses using gain- and loss-of-function approaches. Chromatin immunoprecipitation (ChIP) was performed to explore the molecular mechanisms by arecoline and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) treatment.. We demonstrated that deregulated miR-30a and miR-379 could represent a mechanism for the silencing of ADHFE1 and ALDH1A2 in OSCC through targeting DNMT3B. Ectopic expression of miR-30a and miR-379 could induce re-expression of methylation-silenced ADHFE1 and ALDH1A2, and lead to growth inhibition in oral cancer cells. Furthermore, the dysregulation of the miRNAs and DNMT-3B may result from exposure to tobacco smoking and betel quid chewing.. Our results demonstrate that tobacco smoking and betel quid chewing could repress miR-30a and miR-379, which upregulate the DNMT3B expression, in turn, lead to the hypermethylation of ADHFE1 and ALDH1A genes, consequently, promote the oncogenic activity. These findings highlight the potential use of retinoids in combination with epigenetic modifiers for the prevention or treatment of oral cancer.

Topics: Alcohol Oxidoreductases; Aldehyde Dehydrogenase 1 Family; Arecoline; Carcinogenesis; Carcinoma, Squamous Cell; Cell Line, Tumor; DNA (Cytosine-5-)-Methyltransferases; DNA Methyltransferase 3B; Gene Expression Regulation, Neoplastic; Gene Silencing; Humans; Metabolic Networks and Pathways; MicroRNAs; Mitochondrial Proteins; Mouth Neoplasms; Nitrosamines; Retinal Dehydrogenase; Tretinoin

Topics: Animals; B7-H1 Antigen; Carcinoma, Squamous Cell; CD8-Positive T-Lymphocytes; Cell Line, Tumor; Mice; Mice, Inbred C3H; Mouth Neoplasms; Nanoparticles; Polyethylene Glycols; Squamous Cell Carcinoma of Head and Neck; Tretinoin; Tumor Microenvironment

To gain a greater understanding of oral squamous cell carcinoma (OSCC) we investigated the actions of all-trans-retinoic acid (RA; a retinoid), bexarotene (a pan-RXR agonist), and forkhead box (FOX) transcription factors in human OSCC-derived cell lines. RA and bexarotene have been shown to limit several oncogenic pathways in many cell types. FOXO proteins typically are associated with tumor suppressive activities, whereas FOXM1 acts as an oncogene when overexpressed in several cancers. RA and/or bexarotene increased the transcript levels of FOXO1, FOXO3A, and TRAIL receptors; reduced the transcript levels of FOXM1, Aurora kinase B (AURKB), and vascular endothelial growth factor A (VEGFA); and decreased the proliferation of OSCC-derived cell lines. Also, RA and/or bexarotene influenced the recruitment of FOXO3A and FOXM1 to target genes. Additionally, FOXM1 depletion reduced cell proliferation, decreased transcript levels of downstream targets of FOXM1, and increased transcript levels of TRAIL receptors. Overexpression of FOXO3A decreased proliferation and increased binding of histone deacetylases (HDACs) 1 and 2 at the FOXM1, AURKB, and VEGFA promoters. This research suggests novel influences of the drugs RA and bexarotene on the expression of FOXM1 and FOXO3A in transcriptional regulatory pathways of human OSCC.

Topics: Antineoplastic Agents; Bexarotene; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Forkhead Box Protein M1; Forkhead Box Protein O3; Gene Expression; Gene Knockdown Techniques; Histone Deacetylases; Humans; Mouth Neoplasms; Promoter Regions, Genetic; Retinoids; RNA, Messenger; Tretinoin

Oral squamous cell carcinoma (OSCC), which may arise from oral dysplasia, is one of the most prevalent cancers around the world. In recent years, all-trans retinoic acid (ATRA) has shown great potential in cancer treatment. However, the molecular mechanism for the anti-tumor effects of ATRA remains unclear.. After treated with ATRA, inhibition of cell proliferation of OSCC and oral dysplasia cell lines, CAL27 and DOK, respectively, was analyzed by a Cell Counting Kit-8 (CCK8) assay. The cell cycle arrest, cell apoptosis induction, and PD-L1 expression level were measured by flow cytometry. A small molecular inhibitor was utilized to block STAT3 pathway, and the related proteins expression was measured by Western Blot.. The present study demonstrated that ATRA inhibited cell proliferation at 5-75 μmol/L, arrested cell cycle at S and G2-phase, induced apoptosis effect in OSCC, and oral dysplasia cell line, CAL27 and DOK, respectively. ATRA led to inhibition of p-STAT3, p-JAK2, increased the level of p-ERK, and significantly decreased the PD-L1 expression. Moreover, targeting STAT3 signaling increased (P < .001) the level of cleaved caspase-3 and effectively (P < .001) decreased the expression of cyclin A2 and PD-L1. The effect of ATRA on cell growth inhibition, apoptosis induction, and PD-L1 expression decrease was significantly (P < .05) enhanced after the STAT3 signaling blockade.. These findings suggested that ATRA-induced anti-tumor effects and downregulated PD-L1 expression via STAT3 signaling inhibition in both OSCC and oral dysplasia.

Topics: Apoptosis; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Humans; Mouth Neoplasms; Signal Transduction; STAT3 Transcription Factor; Tretinoin

To determine the expression profile and potential roles of CD24 in oral squamous cell carcinoma and explore the values of CD24 function as a potential target of clinical therapy.. Semi-quantitative immunohistochemistry was used to construct the expression profile of CD24 in 78 human oral tissues and 59 Hamster buccal pouch tissues. Real-time RT-PCR and Western blot were used to analyze the CD24 expression levels in oral DOK4 cells, oral cancer CAL-27 and WSU-HN6 cells. Then these two cancer cell lines were selected to evaluate the effect of all-trans retinoic acid (ATRA) and CD24 antibody on CD24 expression, and the proliferation and tumorsphere formation capacity of these two cell lines.. CD24 expression was found significantly elevated in both human and animal tissues compared with normal and benign tissues (P<0.05), as well as in oral cancer CAL-27 and WSU-HN6 cells compared with DOK cells (P<0.05). CAL-27 and WSU-HN6 cells possess increased proliferative and specific tumorsphere formation capability compared with DOK cells (P<0.05). Both ATRA and CD24 antibody were able to effectively inhibit the proliferation and tumorsphere formation of CAL-27 and WSU-HN6 cells (P<0.05). Among them ATRA at least involved partially in the proliferation by down-regulating the CD24 expression (P<0.05), while CD24 antibody blocking had no effect on the CD24 expression.. CD24 was upregulated in oral cancer and functioned as a potential factor that promoted the proliferation and tumorsphere formation of CAL-27 and WSU-HN6 cells. Both ATRA and CD24 antibody might effectively inhibit the proliferation and tumorsphere formation of CAL-27 and WSU-HN6 cells and function as a potential therapy target.

Topics: Animals; Carcinoma, Squamous Cell; CD24 Antigen; Cell Line, Tumor; Cricetinae; Down-Regulation; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Mouth Mucosa; Mouth Neoplasms; Tretinoin

Cancer stem cells (CSCs) drive tumour spread and therapeutic resistance, and can undergo epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET) to switch between epithelial and post-EMT sub-populations. Examining oral squamous cell carcinoma (OSCC), we now show that increased phenotypic plasticity, the ability to undergo EMT/MET, underlies increased CSC therapeutic resistance within both the epithelial and post-EMT sub-populations. The post-EMT CSCs that possess plasticity exhibit particularly enhanced therapeutic resistance and are defined by a CD44(high)EpCAM(low/-) CD24(+) cell surface marker profile. Treatment with TGFβ and retinoic acid (RA) enabled enrichment of this sub-population for therapeutic testing, through which the endoplasmic reticulum (ER) stressor and autophagy inhibitor Thapsigargin was shown to selectively target these cells. Demonstration of the link between phenotypic plasticity and therapeutic resistance, and development of an in vitro method for enrichment of a highly resistant CSC sub-population, provides an opportunity for the development of improved chemotherapeutic agents that can eliminate CSCs.

Topics: Animals; Antineoplastic Agents; Carcinoma, Squamous Cell; CD24 Antigen; Cell Line; Cell Line, Tumor; Drug Resistance, Neoplasm; Epithelial Cell Adhesion Molecule; Epithelial-Mesenchymal Transition; Female; Humans; Hyaluronan Receptors; Male; Mice; Mice, Inbred NOD; Mice, SCID; Mouth Neoplasms; Neoplastic Stem Cells; Phenotype; Thapsigargin; Transforming Growth Factor beta; Tretinoin

All-trans retinoic acid (ATRA) has been demonstrated to inhibit tumor growth by restoration of gap junctional intercellular communication (GJIC) via upregulation of connexin (Cx) expression in some solid tumors. However, the relationship between ATRA and GJIC remains unclear in oral squamous cell carcinoma (OSCC). The aim of this study was to investigate the effect of ATRA on the GJIC function of OSCC.. We measured the effects of ATRA on the viability and cell cycle distribution of SCC9 and Tca8113 OSCC cells. The GJIC function was observed using the scrape-loading dye transfer technique, and the mRNA and protein levels of Cx32 and Cx43 were detected by qRT-PCR, Western blot, and immunofluorescence assays.. ATRA inhibited the growth of OSCC cells in a dose- and time-dependent manner (P <0.05) and caused cell cycle arrest. ATRA-treated cells showed a 2.69-fold and 2.06-fold enhancement of GJIC in SCC9 and Tca8113 cells, respectively (P <0.05). Moreover, ATRA induced upregulation of Cx32 and Cx43 at both the mRNA and protein levels in OSCC cells.. Our results indicated that restoration of GJIC via enhanced Cx32 and Cx43 expression might serve as a novel mechanism for the anti-tumor effect of ATRA in OSCC.

Topics: Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Communication; Connexin 43; Connexins; Gap Junction beta-1 Protein; Gap Junctions; Gene Expression Regulation, Neoplastic; Humans; Mouth Neoplasms; RNA, Messenger; Tretinoin; Tumor Cells, Cultured; Up-Regulation

To evaluate disease dynamics, treatment results, and frequency of malignant transformation. Ten-year single center retrospective study. The study included 171 patients, 28-99 years old. Follow-up was 1-16 years. 49.5% exhibited changes in clinical presentation, with 19% yearly increase of probability for type shift. Index of extent (number of oral locations) showed a mean 40% decrease and 94.1% reported improvement. There were significant differences between treated and untreated patients (P=0.012). Patients with or without systemic diseases had identical treatment requirements for oral lesions. The prevalence of SCC was 5.8%. Oral lichen planus constantly changes presentation and extent of involvement. The effect of systemic diseases was insignificant in the present study. There is a clear value for treatment to reduce the extent of lesions. The results indicate that all clinical forms of the disease need to be equally followed since the clinical presentation typically changes over time, while malignant transformation can occur in all forms.

Topics: Adult; Aged; Aged, 80 and over; Anti-Inflammatory Agents; Carcinoma, Squamous Cell; Cell Transformation, Neoplastic; Clobetasol; Dexamethasone; Female; Humans; Lichen Planus, Oral; Male; Middle Aged; Mouth Neoplasms; Precancerous Conditions; Prednisone; Prevalence; Retrospective Studies; Tacrolimus; Tretinoin; Triamcinolone

Oral squamous cell carcinoma (OSCC) may arise from potentially malignant oral lesions. All-trans retinoic acid (atRA), which plays a role in cell growth and differentiation, has been studied as a possible chemotherapeutic agent in the prevention of this progression. While the mechanism by which atRA suppresses cell growth has not been completely elucidated, it is known that homeobox genes are atRA targets. To determine if these genes are involved in the atRA-mediated OSCC growth inhibition, PCR array was performed to evaluate the expression of 84 homeobox genes in atRA-sensitive SCC-25 cells compared to atRA-resistant SCC-9 cells following 7 days with atRA treatment. Results showed that the expression of 8 homeobox genes was downregulated and expression of 4 was upregulated in SCC-25 cells but not in SCC-9 cells. Gene expression levels were confirmed for seven of these genes by RT-qPCR. Expression of three genes that showed threefold downregulation was evaluated in SCC-25 cells treated with atRA for 3, 5, and 7 days. Three different patterns of atRA-dependent gene expression were observed. ALX1 showed downregulation only on day 7. DLX3 showed reduced expression on day 3 and further reduced on day 7. TLX1 showed downregulation only on days 5 and 7. Clearly the expression of homeobox genes is modulated by atRA in OSCC cell lines. However, the time course of this modulation suggests that these genes are not direct targets of atRA mediating OSCC growth suppression. Instead they appear to act as downstream effectors of atRA signaling.

Topics: Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Gene Expression Regulation, Neoplastic; Homeodomain Proteins; Humans; Models, Biological; Mouth Neoplasms; Polymerase Chain Reaction; Tretinoin

To examine the expression of cytokeratin-13 (CK-13) in oral squamous cell carcinoma (OSCC) and to discuss the effects of all-trans retinoic acid (ATRA) or arsenic trioxide (As2 O3) on the differentiation of human oral undifferentiated squamous cell carcinoma cell line KB cells.. The cultured KB cells were divided into three groups, ATRA group, As2 O3 group, and control. The expression of CK-13 in KB cells was detected using the immunofluorescence before and after KB cells were induced by ATRA or As2 O3.. The expression rates of CK-13 in KB cells in the ATRA group and As2 O3 group were significantly higher than that in the control (P < 0.05), but there was no significant difference in the expression between ATRA and As2 O3 group(P > 0.05).. ATRA and As2 O3 both have the ability to differentiate the KB cells, and the expression is associated with the degree of tumor differentiation. CK-13 may serve as a molecular marker to evaluate the effect of the differentiation treatment on OSCC.

Topics: Arsenic Trioxide; Arsenicals; Carcinoma, Squamous Cell; Cell Differentiation; Fluorescent Antibody Technique; Humans; KB Cells; Keratin-13; Mouth Neoplasms; Oxides; Tretinoin

The transcriptional silencing of some cell cycle inhibitors and tumor suppressors, such as p16 and retinoic acid receptor beta(2), by DNA hypermethylation at CpG islands is commonly found in human oral squamous carcinoma cells. We examined the effects of the DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine (5-Aza; 0.25 mg/kg body weight), all-trans retinoic acid (RA; given at 100 microg/kg body weight and 1 mg/kg body weight), and the combination of 5-Aza and the low-dose RA on murine oral cavity carcinogenesis induced by the carcinogen 4-nitroquinoline 1-oxide (4-NQO) in a mouse model. All the drug treatments were done for 15 weeks after a 10-week 4-NQO treatment. Mice in all drug treatment groups showed decreases in the average numbers of neoplastic tongue lesions. The combination of 5-Aza and RA effectively attenuated tongue lesion severity. Although all drug treatments limited the increase in the percentage of proliferating cell nuclear antigen-positive cells and the decrease in the percentage of p16-positive cells caused by the 4-NQO treatment in mouse tongue epithelial regions without visible lesions and in the neoplastic tongue lesions, the combination of 5-Aza and RA was the most effective. Collectively, our results show that the combination of a DNA demethylating drug and RA has potential as a strategy to reduce oral cavity cancer in this 4-NQO model.

Topics: 4-Nitroquinoline-1-oxide; Animals; Antineoplastic Combined Chemotherapy Protocols; Azacitidine; Carcinogens; Carcinoma, Squamous Cell; Cyclin-Dependent Kinase Inhibitor p16; Cyclooxygenase 2; Decitabine; DNA Modification Methylases; Female; Immunoenzyme Techniques; Mice; Mice, Inbred C57BL; Mouth Mucosa; Mouth Neoplasms; Proliferating Cell Nuclear Antigen; Proto-Oncogene Proteins c-myb; Receptors, Retinoic Acid; Retinoids; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tretinoin

Antisense oligonucleotides against hTR (As-ODN-hTR) have shown promising results as treatment strategies for various human malignancies. All-trans retinoic acid (ATRA) is a signalling molecule with important roles in differentiation and apoptosis. Biological responses to ATRA are currently used therapeutically in various human cancers. The aim of this study was to evaluate the anti-tumor effects of As-ODN-hTR combined with ATRA in vivo.. In situ human oral squamous cell carcinoma (OSCC) models were established by subcutaneous injection of Tca8113 cells. Mice were treated with sense oligonucleotides against hTR(S-ODN-hTR) alone, As-ODN-hTR alone, ATRA alone, As-ODN-hTR plus ATRA, or S-ODN-hTR plus ATRA. Tumor size and weight were assessed in the mice. Telomerase activity was detected by a TRAP assay, apoptotic cells were evaluated with a Tunel assay, the expression of apoptosis-related proteins (Bcl-2 and Bax) was evaluated by immunohistochemistry and ultrastructural morphological changes in the tumor specimen were examined.. Both As-ODN-hTR and ATRA can significantly inhibit tumor growth in this OSCC xenograft solid-tumor model, and the combination of the two agents had a synergistic anti-tumorogenic effect. We also demonstrated that this anti-tumor effect correlated with inhibition of telomerase activity. Furthermore, significant increases in the number of apoptotic cells, typical apoptotic morphology and a downregulation of the anti-apoptotic protein, bcl-2 were observed in the treated tissues.. The combination of As-ODN-hTR and ATRA has a synergistic anti-tumor effect. This anti-tumor effect can be mainly attributed to apoptosis induced by a decrease in telomerase activity. Bcl-2 plays an important role in this process. Therefore, combining As-ODN-hTR and ATRA may be an approach for the treatment of human oral squamous cell carcinoma.

Topics: Animals; Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Line, Tumor; Drug Synergism; Female; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Mouth Neoplasms; Oligonucleotides, Antisense; Tretinoin; Xenograft Model Antitumor Assays

All-trans retinoic acid (ATRA) and sodium butyrate (SB) have shown growth-inhibitory and differentiation-inducing properties to tumor cells when used as single agents or in combination, but the exact molecular mechanism still remains to be determined. In order to determine the mechanism of the synergy in treatment with RA and SB, we evaluated the growth inhibition capability of ATRA and SB, alone or in combination, in human oral squamous carcinoma cell lines SCC-1 and SCC-9, and identified the expression of cell cycle-related genes. ATRA and SB inhibited cell growth and induced cell cycle G1 arrest. The inhibition effect was more pronounced with SB than with ATRA (p = 0.000). There were interactions between ATRA and SB (p = 0.000). Consistent with the inhibition effect and G1 arrest, ATRA and SB, alone or in combination, induced the expression of G1 phase markers cyclin-dependent kinase (CDK) 6, p21, and p27; inhibited the expression of S-G2 phase proteins CDK2; and decreased Rb phosphorylation. Cyclin D1 expression was increased in the SB- and ATRA + SB-treated groups, but inhibited in the ATRA-treated group. Cyclin B1 and cyclin E expression was slightly decreased in the SB- and ATRA + SB-treated groups, but did not change in the ATRA-treated group. These results indicate that the growth inhibition and G1 arrest of oral squamous carcinoma cells in response to ATRA and/or SB correlates with the induction of G1 phase cell cycle regulatory proteins CDK6, p21, and p27 and the inhibition of S-G2 phase cell cycle regulatory protein CDK2.

Topics: Butyrates; Carcinoma, Squamous Cell; Cell Cycle; Cell Proliferation; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinase 6; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; Humans; Intracellular Signaling Peptides and Proteins; Mouth Neoplasms; Tretinoin

In this study, the effects of all-trans retinoic acid (ATRA) on human oral cancer cells with regard to cell growth, the cell cycle, and alkaline phosphatase (ALP) activity were evaluated. Human oral cancer KB cells were treated with various concentrations of ATRA, and cell growth was then determined using the MTT viability assay. The cell-cycle distribution and ALP activity were analysed using a flow cytometer and chemical analyser, respectively. The KB cells were inhibited by ATRA at concentrations of 1-16 microM (1 microM, P<0.05; 2 microM, P<0.01; 4, 8 and 16 microM, P<0.001) in a dose-dependent manner. ATRA arrested KB cells in the G0/G1 phase. The ALP activity in KB cells was increased by ATRA. This is one of the first studies to focus on the expression of ALP in human head-and-neck carcinoma cells treated with retinoids. These findings suggest that the anti-tumour effects of ATRA on human oral cancer are associated with G0/G1 phase arrest and an increase in ALP activity.

Topics: Alkaline Phosphatase; Antineoplastic Agents; Apoptosis; Carcinoma, Squamous Cell; Dose-Response Relationship, Drug; Flow Cytometry; G1 Phase; Humans; KB Cells; Mouth Neoplasms; Resting Phase, Cell Cycle; Tretinoin; Up-Regulation

Retinoids are known to suppress carcinogenesis in various epithelial tissues. Among them, all-trans-retinoic acid (atRA) is recognized as one such active retinoid. However, despite the known anticarcinogenic activity of atRA, it exhibits its short plasma half-life during repeated oral administration due to the "acute retinoid resistance" in the liver. This has been the major limitation in clinical applications of atRA. Therefore, in order to render atRA more suitable for clinical uses, sustained delivery of atRA using biodegradable microspheres is suggested in this study. When 50 mg atRA/kg of atRA-loaded microspheres were subcutaneously administered to rats once, the atRA concentration in plasma was maintained around 6.5 ng/ml for 7 weeks, with only minor signs of toxicity. When the chemopreventive efficacy of atRA-loaded microspheres was evaluated using a model of 4-nitroquinoline 1-oxide-induced oral carcinogenesis in F344 rats, a single injection of atRA-loaded microspheres significantly suppressed oral carcinogenesis. Additional injections of atRA-loaded microspheres, however, did not indicate further suppression of carcinogenesis.

Topics: 4-Nitroquinoline-1-oxide; Animals; Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Transformation, Neoplastic; Delayed-Action Preparations; Drug Carriers; Drug Compounding; Male; Microspheres; Mouth Neoplasms; Neoplasms, Experimental; Palatal Neoplasms; Polyesters; Polyethylene Glycols; Precancerous Conditions; Rats; Rats, Inbred F344; Solubility; Tongue Neoplasms; Tretinoin

We investigated the relationship between cell growth and differentiation and COX-2 expression in oral squamous cell carcinoma (SCC) in vitro and in vivo. Treatment of SCC25 oral squamous carcinoma cells with sodium butyrate (SB) at 0.5-5 mM or all-trans retinoic acid (ATRA) at 3-300 microM inhibited cell growth and induced apoptosis in a dose-dependent manner with concomittant increases in expression of keratin 13, p21WAF1/Cip1 and p27Kip1 and decreases in expression of COX-2. These effects were more pronounced with SB than with ATRA. Injection of SB or ATRA near SCC25-derived tumors in nude mice resulted in inhibition of growth and elevation of differentiation of the tumor accompanied by marked keratinization and increased expression of keratin 13 and decreased expression of COX-2. These results show that the differentiation-inducing agents, particularly SB, suppress growth of oral squamous carcinoma cells through apoptosis and induce cell differentiation possibly through mechanisms involving COX-2, p27Kip1 and/or p21WAF1/Cip1 in vitro and in vivo.

Topics: Animals; Apoptosis; Blotting, Western; Butyrates; Carcinoma, Squamous Cell; Cell Cycle Proteins; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; Cyclooxygenase 2; DNA Primers; Female; Gene Expression Regulation, Neoplastic; Head and Neck Neoplasms; Humans; Immunohistochemistry; Isobutyrates; Keratins; Membrane Proteins; Mice; Mice, Inbred BALB C; Mice, Nude; Mouth Neoplasms; Prostaglandin-Endoperoxide Synthases; Reverse Transcriptase Polymerase Chain Reaction; RNA; Time Factors; Tretinoin; Tumor Suppressor Proteins

Systemic retinoic acid (RA) treatment for chemoprevention of squamous cell carcinoma of the head and neck (HNSCC) is limited by RA's toxic side effects at therapeutic doses. The pulsed-dye laser (PDL), through a mechanism of selective vascular targeting, may allow reduction of the RA dose to one that is better tolerated when these treatments are used in combination. This study tests our hypothesis that combination therapy of PDL irradiation and low-dose systemic RA is as effective as high-dose RA therapy alone in the chemoprevention of HNSCC.. Randomized, prospective study in a hamster model.. Dysplastic lesions were induced in the cheek pouches of 48 hamsters by painting with topical 9,10-dimethl-1,2-benzanthrancene (DMBA). The hamsters were randomly divided into four treatment groups: 1) control (no treatment); 2) PDL irradiation only; 3) 5.0 mg RA (all-trans retinoid, 5.0 mg/kg per day, intraperitoneally [IP]); and (4) PDL + 0.5 mg RA (0.5 mg/kg per day, IP). The PDL irradiation was conducted at day 0 and 15, whereas the RA treatment was continued for 27 days. Tumor burden was measured over time.. The lesions in all of three treatment groups grow more slowly than the untreated controls. The combination treatment of PDL and RA had the greatest inhibitory effect on tumors.. This study suggests that combination treatment of PDL and low-dose RA is more effective than high-dose RA alone in the chemoprevention of HNSCC in a hamster cheek-pouch model, so that it should allow greatly improved tolerance of this regimen.

Topics: Animals; Antineoplastic Agents; Carcinoma, Squamous Cell; Cheek; Cricetinae; Disease Models, Animal; Laser Therapy; Male; Mesocricetus; Mouth Mucosa; Mouth Neoplasms; Prospective Studies; Random Allocation; Tretinoin

Angiogenesis and tumor-associated immunosuppression are two of the hallmarks of carcinogenesis. In previous studies we demonstrated in vitro that HNSCC tumor cells attract monocytes via monocyte chemotactic protein-1 (MCP-1) and activate them via transforming growth factor-beta 1(TGF-beta1) to secrete interleukin (IL)-1alpha, which in turn stimulates tumor cells to secrete increased levels of the angiogenic and immunosuppressive vascular endothelial growth factor (VEGF). These findings suggest that interaction between the immune system and VEGF-mediated angiogenesis is important for progression of HNSCC. Recent studies in vitro show that retinoic acid (RA) downregulates the release of MCP-1 and TGF-beta1 by tumor cells. Therefore, we investigated the ability of RA to modulate the ability of tumor cells to recruit and activate monocytes for participation in VEGF-mediated angiogenesis and immunosuppression in vivo.. Mice (ten/group) were injected daily with RA (160 microg/kg) for 3 weeks. After that time mice were sacrificed, and paraffin sections of tumors were obtained and stained for VEGF-A, CD68, and PECAM (CD31) by immunohistochemistry. The lungs, liver, and myocardium were analyzed for macro- and micrometastases. The plasma protein levels of VEGF-A and MCP-1 were determined by ELISA.. In RA-treated mice tumors regressed completely and RA prevented metastases (p=0.00) and macrophage infiltration (p=0.007). Treated mice downregulated VEGF-A (0 pg/ml) and MCP-1 (12 pg/ml) in peripheral blood (p=0.001).. Our findings suggest a new therapeutic possibility: the development of treatment protocols that can block each of the ways in which tumors induce new blood vessel growth and immunosuppression of the host.

Topics: Angiogenesis Inhibitors; Animals; Carcinoma, Squamous Cell; Cell Line, Tumor; Chemokine CCL2; Disease Progression; Down-Regulation; Humans; Immune Tolerance; Interleukin-1; Macrophage Activation; Male; Mice; Mice, Inbred A; Mouth Neoplasms; Neoplasm Metastasis; Neoplasm Transplantation; Transforming Growth Factor beta; Transforming Growth Factor beta1; Tretinoin; Vascular Endothelial Growth Factor A

Retinoic acid receptor-beta(2) (RAR-beta(2)) expression is suppressed in oral premalignant lesions and head and neck squamous cell carcinomas (HNSCCs). This study was conducted to determine whether RAR-beta(2) gene expression in such lesions can be silenced by promoter methylation.. RAR-beta(2) methylation was analyzed in DNA samples from 22 pairs of primary HNSCC and adjacent normal epithelium, 124 samples of oral leukoplakia, and 18 HNSCC cell lines using methylation-specific PCR. RAR-beta(2) promoter was methylated in 67, 56, and 53% of HNSCC tumors, HNSCC cell lines, and microdissected oral leukoplakia specimens, respectively. RAR-beta(2) hypermethylation was confirmed by sodium bisulfite-PCR combined with restriction enzyme digestion analysis and by random cloning and sequencing of bisulfite-treated DNA isolates.. Significantly higher RAR-beta(2) hypermethylation levels were found in tumor tissue compared with adjacent normal tissue (P = 0.002). RAR-beta(2) methylation in the cell lines was correlated with loss of RAR-beta(2) expression (P = 0.013) and inversely related to the presence of mutated p53 (P = 0.025). The demethylating agent 5-aza-2'-deoxycytidine (5-aza-CdR) restored RAR-beta(2) inducibility by all-trans-retinoic acid (ATRA) in some of the cell lines, which posses a methylated RAR-beta(2) promoter. In some cell lines, this effect was associated with increased growth inhibition after combined treatment with 5-aza-CdR and ATRA.. RAR-beta(2) silencing by methylation is an early event in head and neck carcinogenesis; 5-Aza-CdR can restore RAR-beta(2) inducibility by ATRA in most cell lines, and the combination of 5-aza-CdR and ATRA is more effective in growth inhibition than single agents.

Topics: Adult; Aged; Aged, 80 and over; Base Sequence; Carcinoma, Squamous Cell; Cell Division; Cell Line, Tumor; Cloning, Molecular; DNA Methylation; DNA Primers; DNA, Neoplasm; Female; Gene Silencing; Head and Neck Neoplasms; Humans; Leukoplakia, Oral; Male; Middle Aged; Molecular Sequence Data; Mouth Neoplasms; Polymerase Chain Reaction; Precancerous Conditions; Promoter Regions, Genetic; Receptors, Retinoic Acid; Tretinoin

This study examines whether a combination of laser microvascular targeting, mucosal adhesive film (MAF) and retinoic acid (RA) techniques would improve the efficacy for oral cancer chemoprevention. The cheek pouches of 48 hamsters were painted with 7,12-dimethlbenz[a]nthrancene to produce premalignant lesions. There were four groups of 12 each: (1) control; (2) pulsed dye laser (PDL) treatment; (3) topical MAF/RA patch treatment; and (4) combined treatment of PDL and MAF/RA. The treatments were conducted for 27 days. Our findings indicate that this new combined treatment is safe and effective for oral cancer chemoprevention, and warrants further study.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Administration, Topical; Animals; Antineoplastic Agents; Biofilms; Carcinogens; Chemoprevention; Combined Modality Therapy; Cricetinae; Laser Therapy; Male; Mesocricetus; Mouth Mucosa; Mouth Neoplasms; Tretinoin

The study examines the role of the pulsed-dye laser at 585 nm, coupled with retinoic acid at therapeutic dose of 5.0 mg/kg body weight, in inhibiting chemically induced tumor growth in the hamster cheek pouch to determine whether pulsed-dye laser therapy can inhibit tumor growth and whether a combination of pulsed-dye laser and retinoic acid has a synergic effect on treatment efficacy.. Randomized, prospective study of hamster model.. Forty-eight male golden Syrian hamsters were painted with 0.5% solution of 9,10-dimethyl-1,2-benzanthracene in acetone for 6 weeks to induce dysplasia in both sides of the cheek pouches. The hamsters were then randomly divided into four groups of 12 hamsters each as follows: (1) control group, (2) pulsed-dye laser treatment only (8.0 J/cm(2) and two pulses), (3) retinoic acid treatment only (5.0 mg/kg/d by intraperitoneal injection), and (4) combined pulsed-dye laser and retinoic acid treatment. The treatment period was 40 days. Tumors were measured throughout the study.. The results indicated that retinoic acid and pulsed-dye laser each significantly delay tumor growth and reduce tumor volume when used alone. Tumor volumes were statistically different among the treatment groups. There was also a statistical difference in tumor volume between the retinoic acid treatment group and the combined pulsed-dye laser and retinoic acid treatment group.. The study demonstrated the greater advantage of combining pulsed-dye laser with retinoic acid over using either retinoic acid or pulsed-dye laser alone for delay of oral cancer progression. Clinical trials are warranted to establish efficacy in humans.

Topics: Animals; Antineoplastic Agents; Combined Modality Therapy; Cricetinae; Injections, Intraperitoneal; Laser Therapy; Male; Mouth Mucosa; Mouth Neoplasms; Neoplasm Staging; Prospective Studies; Random Allocation; Tretinoin

Oral cancer is a common malignancy. Chemoprevention is a promising treatment strategy but it produces systemic toxic effects. Topical application of chemopreventive agents is an attractive alternative that reduces toxic effects. This study is based on the hypothesis that topical application of mucosal adhesive film (MAF), as a means to deliver tretinoin, is effective and safe for oral cancer chemoprevention.. Randomized animal study conducted at the Boston University School of Medicine.. This study uses the hamster cheek-pouch model to test efficacy and safety of the MAF/tretinoin patch for oral cancer prevention. The oral mucosa of 36 hamsters was painted with dimethylbenzanthracene to produce premalignant lesions. The 36 hamsters were divided into 3 groups of 12 hamsters each as follows: (1) control, no treatment; (2) systemic tretinoin (5.0 mg/kg per day, intraperitoneally); and (3) topically applied MAF/tretinoin patch (0.45 mg tretinoin/cm2, once daily). Treatments continued for 40 days.. Tumor growth and burden were measured over time. The duration of MAF patch retention on mucosa and local tissue reaction to the treatment were also evaluated.. The patch stayed on the mucosa for at least 5 hours with no evidence of inflammatory or other adverse reactions from the treated tissue. There was a significant difference in the tumor growth measurement between the control and systemic tretinoin groups (P<.001), and between the control and MAF patch groups (P<.001).. This is the first study, to our knowledge, to use a polymer MAF technique for oral cancer prevention. The MAF/tretinoin patch is safe and effective for such chemoprevention in the hamster model.

Topics: Administration, Topical; Animals; Antineoplastic Agents; Cricetinae; Male; Mouth Mucosa; Mouth Neoplasms; Tretinoin

A cell line, AMOS-III has been established from the surgically resected specimen of an untreated primary human oral squamous cell carcinoma of the floor of mouth from a chronic smokeless tobacco consumer. Immunocytochemical analysis showed epithelial specific antigen, cytokeratins 5, 10, 13 and 16 and integrin alpha(6) markers in AMOS-III cells, confirming the epithelial lineage of the cell line. Analyses of morphology, ultrastructure, karyotype, anchorage independent growth and immunocytochemical properties of the cell line demonstrated the transformed phenotype of epithelial cells. AMOS-III cells have doubling time of 42-44 h. Giemsa-banding patterns of chromosomes confirmed the human origin of the AMOS-III cells. Molecular analysis of cancer-related gene products, p53 and p21(cip1/waf1) showed the presence of wild type p21(cip1/waf1) and truncated p53 proteins. The molecular mechanism underlying the action of retinoids in preventing the occurrence of second primary tumors in oral cancer patients remain to be clearly defined. Treatment of AMOS-III cells with all-trans retinoic acid (ATRA) at 10(-4) microM resulted in 81% cell death. ATRA treatment resulted in enhanced expression of p21(cip1/waf1), nuclear translocation of retinoic acid receptors and apoptotic cell death. Thus, this cell line provides an in vitro model for elucidating the mechanism involving p53 inactivation and p21(cip1/waf1) overexpression in smokeless tobacco-induced oral cancer. Furthermore, the ATRA responsiveness of the cell line underscores its potential utility in identifying the retinoid responsive molecular targets in oral cancer cells.

Topics: Antioxidants; Apoptosis; Biomarkers, Tumor; Carcinoma, Squamous Cell; Cell Line, Tumor; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; DNA Mutational Analysis; Genes, p53; Humans; Immunoblotting; Karyotyping; Male; Microscopy, Confocal; Middle Aged; Mouth Neoplasms; Tobacco, Smokeless; Tretinoin

Indomethacin, an NSAID capable of inhibiting the effect of both cyclooxygenase and lipooxygenase, has been reported to repress the growth of breast cancer, skin cancer and head & neck cancer, etc. Inhibition in the some cell lines of oral squamous cell carcinoma (OSCC) has also been reported. The purpose of this study was primarily to explore the cellular response of human OSCC lines after indomethacin or retinoic acid (RA) treatment and its correlation to apoptosis phenomenon.. Five human OSCC cell lines--KB, SCC15, SCC25, OEC-M1 and OC2--were used for this in vitro study. By direct cell number counting, the cellular response was observed under incremental indomethacin concentrations of 50 microM, 100 microM, 200 microM and 400 microM, in order to select the most appropriate concentration for further study. Then 200 microM indomethacin and all-trans RA at 1 microM were used in the 2nd experiment to explore the intensity of their inhibitory effects individually and potential synergistic inhibition when exerted together. While in the 3rd part, TdT-mediated-dUTP nick-end labeling (TUNEL) method was used for in situ apoptosis assay to see if the apoptosis rate varied with these two agents.. All 5 cell lines constantly showed growth suppression with positive dosage effect of indomethacin. Synergistic inhibition by combined treatment of indomethacin and RA was seen in RA responsive lines of SCC15 and SCC25, whereas other RA-resistant clones showed no synergism of this combined treatment. The in situ detection of apoptosis by TUNEL assay revealed a significantly higher ratio of apoptotic cells in the indomethacin/RA treated SCC15 and SCC25 than in controls.. The study provides the value of further exploration on the mechanism of how indomethacin inhibiting cancer cell growth and how RA-sensitive OSCC cell lines are synergistically suppressed by conjoint treatment of RA and indomethacin. This study also highlights the value to see how the apoptotic pathway responds differently to the indomethacin/RA treatment.

Topics: Apoptosis; Carcinoma, Squamous Cell; Drug Synergism; Humans; Immunohistochemistry; Indomethacin; Mouth Neoplasms; Tretinoin; Tumor Cells, Cultured

Expression of retinoic acid receptor beta (RARbeta) is reported to be absent or down-regulated in oral squamous cell carcinomas. Recently, we found that the growth-inhibitory effect of 9-cis-retinoic acid (9CRA) on oral squamous cell carcinoma may depend on the expression levels of endogenous RARbeta. In order to clarify the role of RARbeta in growth and differentiation, we transfected RARbeta expression vector into oral squamous carcinoma cell lines, HSC-4 and Ho-1-N-1. Both RARbeta-transfected cell lines displayed growth inhibition. Moreover, RARbeta-transfected clones underwent morphological changes, and RARbeta-transfected HSC-4 clones underwent apoptosis even in the absence of 9CRA treatment. In contrast, RARbeta-transfected Ho-1-N-1 clones exhibited cell cycle arrest without undergoing apoptosis initially; however, apoptosis was induced in these cells after 6 days of 9CRA treatment. RARalpha and RARgamma expression was reduced at both the protein and mRNA levels in RARbeta transfectants, whereas the expression of retinoid X receptor alpha (RXRalpha) was not altered. RARb transfectants exhibited alterations in the levels of cell cycle-associated proteins, histone acetyltransferase (HAT) and apoptosis-associated proteins. After 6 days of 9CRA treatment, RARbeta transfectants overexpressed Waf1 / Cip1 / Sdi1 / p21, Kip1 / p27, chk1, p300 / CBP, BAX, Bak, Apaf 1, caspase 3 and caspase 9. Conversely, E2F1, cdc25B and HDAC1 were down-regulated in these transfectants. In addition, histone H4 acetylation was induced in RARb transfectants. These findings suggest that histone acetylation mediated by histone acetyltransferase and p300 / CBP may play a role in the growth arrest and apoptosis induced by RARbeta transfection in oral squamous cell carcinoma.

Topics: Alitretinoin; Antineoplastic Agents; Apoptosis; Carcinoma, Squamous Cell; Cell Cycle; Cell Division; Humans; Mouth Neoplasms; Neoplasm Proteins; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; RNA, Messenger; Transfection; Tretinoin; Tumor Cells, Cultured

Two new canine melanoma cell lines (CMM1 and CMM2) were established from the patients with oral malignant melanomas. Histopathological type of both CMM1 and CMM2 was a mixed cell type consisted of spindle-shaped cells, polygonal cells, and oval cells. Doubling time of CMMI and CMM2 were 18.4 +/- 1.96 hr and 21.0 +/- 0.73 hr, respectively. The effect of two kinds of retinoids (all-trans retinoic acid and 9-cis retinoic acid) on the proliferation of these cells were examined by morphological changes, proliferation assay and apoptosis assay. However, the retinoids did not suppress growth rate of these cells. This result suggests that retinoids used in this study did not induce differentiation, apoptosis, and growth inhibition of the canine melanoma cell lines.

Topics: Alitretinoin; Animals; Antineoplastic Agents; Apoptosis; Cell Division; Dog Diseases; Dogs; Melanoma; Mouth Neoplasms; Retinoids; Tretinoin; Tumor Cells, Cultured

Retinoids inhibit the proliferation of several types of tumour cells, and are used for patients with several malignant tumours. In this study, we examined the effect of retinoic acids (RAs) on the invasive potentials of the oral squamous cell carcinoma (SCC) cells, BHY and HNt. BHY cells expressed all of retinoid nuclear receptors (RARalpha, beta, gamma, and RXRalpha) and cytoplasmic retinoic acid binding proteins (CRABP1 and CRABP2). HNt cells lacked the expression of RARbeta, but expressed other nuclear receptors and CRABPs. All-trans retinoic acid (ATRA) and 13-cis retinoic acid (13-cisRA) (10(-6)and 10(-7)M) inhibited the growth of the cells, but low-dose ATRA and 13-cisRA (10(-8)M) marginally affected the growth of the cells. Surprisingly, low-dose RAs enhanced the activity of tissue-type plasminogen activator (tPA), and activated pro-matrix metalloproteinases (proMMP2 and proMMP9). Activation of proMMP2 and proMMP9 was inhibited by aprotinin, a serine-proteinase, tPA inhibitor. Furthermore, low-dose RAs enhanced the in vitro invasiveness of BHY cells. These results indicate that low-dose RAs enhances the in vitro invasiveness of oral SCC cells via an activation of proMMP2 and proMMP9 probably mediated by the induction of tPA.

Topics: Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Division; Collagenases; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Precursors; Gelatinases; Humans; Isotretinoin; Matrix Metalloproteinase 9; Matrix Metalloproteinases, Membrane-Associated; Metalloendopeptidases; Mouth Neoplasms; Neoplasm Invasiveness; Receptors, Retinoic Acid; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinase-2; Tissue Plasminogen Activator; Tretinoin; Tumor Cells, Cultured; Urokinase-Type Plasminogen Activator

The purpose of this study is to identify the cellular response ofretinoic acid-treated human oral cancer cell lines.. Seven human oral cancer cell lines KB, SCC4, SCC9, SCC15, SCC25, OEC-M1, OC1 and OC2 were used for cell culture experiments. Direct cell number counting method was utilized to evaluate cellular response of these human oral cancer cells at the presence or absence of all-trans RA at 1 mM.. Through 7-day observation, the cell population of SCC9, SCC15 and SCC25 of RA-treated groups decreased when compared with the non RA-treated groups. These three cell lines were further verified using [3H] thymidine incorporation DNA synthesis assay. KB, SCC4, OC1, OC2 and OEC-M1 cell lines did not show growth inhibition at the presence of RA at 1 mM.. The molecular event of how SCC9, SCC15 and SCC25 are inhibited by RA and how KB, OC1, OC2 and OECM1 are resistant to RA can be further explored on the basis of this study.

Topics: Carcinoma, Squamous Cell; Cell Division; DNA; Humans; Mouth Neoplasms; Thymidine; Tretinoin; Tumor Cells, Cultured

This study examined the role of the pulsed-dye laser (PDL) at 585 nm coupled with retinoic acid at therapeutic (5.0 mg/kg) and nontherapeutic (0.5 mg/kg) doses to delay the progression of cancer with a two-hit approach. The existing vasculature is selectively targeted by the laser, whereas retinoic acid inhibits future angiogenesis.. Randomized, prospective study in a murine model.. Twenty-five athymic nude mice were inoculated with oral squamous cell cancers on six flank sites and randomly divided into five groups: 1) control subjects, 2) treatment with 0.5 mg/kg retinoic acid (RA 0.5), 3) treatment with 5.0 mg/kg retinoic acid (RA 5.0), 4) treatment with RA 0.5 + PDL, and 5) treatment with RA 5.0 + PDL. The PDL groups received irradiation after inoculation. The retinoic acid was administered daily. The tumors were counted and measured for 14 days.. The control group developed visible tumors in 50% of the inoculation sites at 3 days compared with 3 days (RA 0.5) and 4 days (RA 5.0) for the retinoic acid groups and 9 days (RA 0.5 + PDL) and 10 days (RA 5.0 + PDL) for the laser treatment groups. There was no tumor growth until day 7 in the RA 5.0 + PDL group. The tumor volume was statistically different between the treatment groups.. This study demonstrated the superiority of a single treatment with the PDL coupled with retinoic acid to delay the progression of cancer when compared with treatment with retinoic acid alone, thus introducing a novel strategy in cancer control.

Topics: Animals; Antineoplastic Agents; Carcinoma, Squamous Cell; Combined Modality Therapy; Data Interpretation, Statistical; Disease Models, Animal; Laser Therapy; Lithotripsy, Laser; Mice; Mice, Nude; Mouth Neoplasms; Neoplasm Transplantation; Neoplasms, Experimental; Prospective Studies; Random Allocation; Time Factors; Tretinoin

Retinoids have been shown to inhibit the growth of many human tumor cells including breast, ovarian and squamous cell carcinoma (SCC). While the exact mechanism of retinoid mediated growth suppression is not known, a role for the retinoic acid receptors (RARs) and retinoid X receptors (RXRs) has been established in both the breast and ovarian tumor cell models. We set out to determine if modulation of RAR/RXR function would alter the retinoid sensitivity of oral SCC cells. We found that the growth of SCC cells was significantly inhibited by treatment with either all-trans-retinoic acid (trans-RA) or the synthetic, conformationally restricted RARgamma selective retinoids MM11254 and MM11389. In order to demonstrate a role for RAR/RXR function in this process, stable oral SCC cell clones constitutively overexpressing the dominant negative mutant RARbeta2 (R269Q) were prepared and shown to exhibit reduced RAR/RXR transcriptional transactivation activity. We found that oral SCC cells exhibiting reduced RAR/RXR function became resistant to growth inhibition by all-trans-RA, MM11254 and MM11389. Likewise, treatment of oral SCC cells with the RARgamma antagonist MM11253 was found to block the ability of MM11254 and MM11389 to inhibit SCC cell growth. Thus, modulation of RAR function through the use of RAR-gamma selective agonists, an RAR-gamma selective antagonist or a pan-RAR dominant negative mutant significantly alters the growth inhibitory response of oral SCC cells to retinoids.

Topics: Arginine; Carcinoma, Squamous Cell; Cell Division; Gene Transfer Techniques; Glutamine; Growth Inhibitors; Humans; Mouth Neoplasms; Mutagenesis, Site-Directed; Receptors, Retinoic Acid; Retinoic Acid Receptor gamma; Retinoids; Tretinoin; Tumor Cells, Cultured

Retinoic acid (RA) has been shown to be effective in suppressing premalignant lesions and preventing second primary malignancies in patients cured of squamous cell carcinoma of the head and neck. However, the precise mechanisms of these effects are still uncertain. In the present study, we examined the effect of 9-cis-RA on the growth of six oral cancer cell lines (HSC-2, HSC-3, HSC-4, Ca9-22, Ho-1-N-1 and Ho-1-u-1). In addition, the relationship among growth and differentiation of tumor cells, RA responsiveness and the expression of nuclear retinoic acid receptors were also investigated. Among the six cell lines examined, five (HSC-2, HSC-3, HSC-4, Ca9-22 and Ho-1-u-1) displayed growth inhibition after treatment with 1x10(-6) M 9-cis-RA, while Ho-1-N-1 cells were resistant to 9-cis-RA. The expression level of RARbeta in 9-cis-RA resistant Ho-1-N-1 cells was very low in comparison with the sensitive cell lines. On the other hand, all of the six the cell lines expressed RARalpha, RARgamma, and RXRalpha at various levels. 9-cis-RA induced accumulation of cell population in G1 phase in HSC-3 cells on the 6th day of the treatment, followed by a marked reduction in the levels of hyperphosphorylated pRB, whereas p53 level was not altered. Interestingly, 9-cis-RA induced transiently the expression of p21(Waf1/Cip1), p27(Kip1), p300, CBP, BAX, Bak and bcl-2 proteins, respectively. This effect was associated with reduction of cyclin D1, cdk4 and CDK-activating kinase (cyclin H and cdk7) protein in HSC-3 cells. These results suggest that the growth inhibitory effect of 9-cis-RA on oral squamous cell carcinoma may depend on the expression levels of RARs, especially RARbeta proteins and RXRalpha proteins, and that 9-cis-RA may provide a powerful therapeutic agent for head and neck cancers.

Topics: Alitretinoin; Apoptosis; Carcinoma, Squamous Cell; Cell Cycle Proteins; Cell Differentiation; Cell Division; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; G1 Phase; Gene Expression Regulation, Neoplastic; Genes, cdc; Humans; Mouth Neoplasms; Receptors, Retinoic Acid; Retinoid X Receptors; RNA, Messenger; Transcription Factors; Tretinoin; Tumor Cells, Cultured

Retinoids, metabolites and synthetic derivatives of vitamin A (retinol), have been shown to inhibit carcinogenesis in various epithelial tissues in animal model systems and to have clinical efficacy as chemotherapeutic agents against certain types of cancer, including squamous cell carcinomas (SCCs). We examined the metabolism of [3H]retinol in normal human cell strains and SCC lines from the oral cavity and skin, and we report here that the cultured normal human epithelial cell strains esterified [3H]retinol to a much greater extent than the SCC lines. Furthermore, microsomal extracts of normal cell strains (e.g., OKF4) exhibited about 7-fold more palmityl-CoA-dependent, phenylmethylsulfonyl fluoride-resistant retinol esterification activity than extracts from SCC lines (e.g., SCC25). The fact that the esteriflcation of retinol was phenylmethylsulfonyl fluoride resistant suggests that the enzyme acyl-CoA:retinol acyltransferase is involved. Culture of both the normal and SCC lines in the presence of 1 microM all-trans-retinoic acid (RA) for 48 h enhanced the formation of [3H]retinyl esters from [3H]retinol. All of the cell lines examined can also metabolize [3H]retinol to [3H]RA, [3H]14-hydroxy-4,14-retroretinol, [3H]retinaldehyde, and [3H]3,4-didehydroretinol, but this metabolism occurs to varying extents in different cell lines. Culture of the cells in the presence of RA for 48 h did not affect the subsequent metabolism of [3H]retinol to [3H]RA and [3H]14-hydroxy-4,14-retroretinol, but it did reduce the metabolism of [3H]retinol to [3H]3,4-didehydroretinol. When cultured for 6-10 h in the presence of nanomolar concentrations of exogenous [3H]retinol, both the normal and SCC lines had much higher intracellular [3H]retinol concentrations, in the micromolar range. No correlation was seen between CRABP II or CRBP I mRNA levels and the levels of either intracellular [3H]retinol or [3H]retinol metabolism in these lines. The reduced ability to esterify retinol in these tumor cells may result in inappropriate cell growth and the loss of normal differentiation responses because of the lack of a sufficient amount of internal retinol stored as retinyl esters.

Topics: Carcinoma, Squamous Cell; Humans; Mouth Neoplasms; Skin Neoplasms; Tretinoin; Tumor Cells, Cultured

We investigated the effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and 9-cis-retinoic acid (9cRA) on parathyroid hormone-related protein (PTHrP) production and its mRNA expression by the human oral squamous carcinoma cell line (HSC-3). The major transcript of PTHrP was 1.5 kb in human HSC-3 cells. In the presence and absence of serum, 1,25(OH)2D3 produced dose-dependent inhibition of PTHrP gene expression and secretion. Significant inhibition by 1,25(OH)2D3 in the presence of serum was observed at 10(-10) M for mRNA expression and 10(-8) M for secretion, whereas under serum-free conditions, 1,25(OH)2D3 significantly suppressed PTHrP mRNA expression at 10(-10) M and secretion at 10(-9) M. Thus the remainder of the experiments were performed under serum-free conditions. After 24 h of incubation, 9cRA decreased dose-dependently PTHrP mRNA expression and PTHrP secretion. Addition of 10(-7) M 1,25(OH)2D3 or 10(-7) M 9cRA to HSC-3 cells significantly suppressed PTHrp transcription within 1 h and the PTHrP secretion within 12 h. Maximal suppression of mRNA expression was maintained for 12-48 h. 9cRA caused a continuous decrease in PTHrP secretion for up to 48 h, whereas the inhibition of secretion by 1,25(OH)2D3 was transient and abolished by 48 h. Neither 1,25(OH)2D3 nor 9cRA altered the stability of PTHrP mRNA. The inhibitory effect of 1,25(OH)2D3 and 9cRA on PTHrP mRNA expression was additive, whereas no additive effect was observed with regard to PTHrP secretion. These results indicate that 1,25(OH)2D3 and 9cRA suppressed PTHrP production and mRNA expression in oral squamous cancer cells, and suggest that transcriptional suppression may act through binding of the heterodimer (vitamin D receptor-retinoid X receptor) to negatively responsive elements of the PTHrP gene.

Topics: Analysis of Variance; Calcitriol; Carcinoma, Squamous Cell; Depression, Chemical; Dose-Response Relationship, Drug; Gene Expression; Humans; Mouth Neoplasms; Parathyroid Hormone-Related Protein; Polymerase Chain Reaction; Protein Biosynthesis; Proteins; Radioimmunoassay; RNA, Messenger; Tretinoin; Tumor Cells, Cultured

Retinoids are a group of vitamin A analogues that have shown promise as chemopreventive and therapeutic agents in many types of malignancy and have been entered in clinical trials with some successful results. To better understand the mechanism that mediates retinoid action and the anti-proliferative effects, we treated 7 human oral squamous-cell carcinoma (SCC) cell lines (FADU, HEp-2, CCL-17, SCC-9, SCC-15, SCC-25 and HN-212) with 10(-6) M of all-trans retinoic acid (ATRA), 9-cis and 13-cis retinoic acid (RA) in continuous for different periods of time. We assessed the extent of growth inhibition, the stability of the anti-proliferative effect and the mRNA expression levels (by RT-PCR) of RA receptors (RARs), retinoid X receptors alpha (RXR alpha) and cytosolic RA-binding proteins (CRBP I and CRABP II) in treated cells compared with controls. The data obtained showed that all 3 RAs were able to inhibit the cellular growth of the tested cell lines, although to a different extent. The cis compounds were able to inhibit the proliferation of all cell lines, whereas ATRA was ineffective in inhibiting the proliferation of the CCL-17 cell line, which was naturally resistant to ATRA concentrations in the range between 10(-5) and 10(-6) M. All inhibitory effects were completely reversible since all cell lines restored their normal growth proliferation within few days after drug removal. RT-PCR analysis of the receptor and cell binding protein status of control and treated cells showed a good correlation between growth inhibition and induction of, or increase in, the expression levels of RAR beta in RA-treated cells. No differences were observed in RAR alpha and RXR alpha mRNA expression levels between control and treated cells. CRBP I, CRABP II and RAR gamma mRNA levels increased in some treated cell lines but not in all.

Topics: Alitretinoin; Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Cycle; Cell Division; Drug Evaluation, Preclinical; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Growth Inhibitors; Humans; Isotretinoin; Mouth Neoplasms; Neoplasm Proteins; Polymerase Chain Reaction; Receptors, Retinoic Acid; Retinoid X Receptors; Retinol-Binding Proteins; Retinol-Binding Proteins, Cellular; Transcription Factors; Tretinoin; Tumor Cells, Cultured; Up-Regulation

Cyclooxygenase-2 expression is up-regulated in transformed cells and tumors. Because this enzyme catalyzes the synthesis of prostaglandins, strategies aimed at suppressing its expression may prove useful in preventing or treating cancer. We investigated the ability of retinoids to suppress phorbol ester-mediated induction of cyclooxygenase-2 in human oral epithelial cells. Treatment with phorbol myristate acetate (PMA) resulted in approximately a 3-fold increase in the production of prostaglandin E2 (PGE2). Retinoids [all-trans-retinoic acid (RA), 13-cis-RA, and retinyl acetate] markedly suppressed PMA-mediated increases in amounts of cyclooxygenase-2 (Cox-2) and the production of PGE2. Retinoids also suppressed the induction of Cox-2 mRNA by PMA. Nuclear run-offs revealed increased rates of Cox-2 transcription after treatment with PMA; this effect was inhibited by all-trans-RA. Transient transfection experiments showed that PMA caused about a 2-fold increase in Cox-2 promoter activity, an effect that was suppressed by all-trans-RA. Our data indicate that treatment of oral epithelial cells with PMA is associated with enhanced transcription of Cox-2 and increased production of PGE2. These effects of PMA were inhibited by retinoids.

Topics: Anticarcinogenic Agents; Biotransformation; Carcinoma, Squamous Cell; Cyclooxygenase 2; Dinoprostone; Diterpenes; Enzyme Induction; Gene Expression Regulation, Neoplastic; Humans; Isoenzymes; Isotretinoin; Membrane Proteins; Mouth Neoplasms; Neoplasm Proteins; Peroxidases; Prostaglandin-Endoperoxide Synthases; Retinyl Esters; Tetradecanoylphorbol Acetate; Transcription, Genetic; Tretinoin; Tumor Cells, Cultured; Vitamin A

Cisplatin (DDP) is commonly used to treat head and neck tumors. Therapy frequently fails due to development of DDP resistance or toxicities associated with DDP therapy. In this study, effects of ALRT1057 [9-cis retinoic acid (9-cis RA)] on DDP cytotoxicity were studied in a human oral squamous carcinoma xenograft model. Mice bearing xenografts were dosed p.o. daily 5 days/week with 30 mg/kg 9-cis RA and/or i.p. twice weekly with 0.3-0.9 mg/kg DDP. Maximum tolerated doses of 9-cis RA and DDP were approximately 60 and >/=2.9 mg/kg, respectively, under their dosing schedules and routes of administration. Control tumors grew rapidly with mean doubling times of 4 +/- 1 days and reached mean volumes of 1982 +/- 199 (SE) mm3 after 24 days. DDP at doses of 0.3, 0.45, and 0.9 mg/kg inhibited tumor growth by 28, 47, and 86%, respectively, 24 days after tumor cell implantation. Thirty mg/kg 9-cis RA inhibited tumor growth by 25%. In combination, 0.3 mg/kg DDP + 30 mg/kg 9-cis RA inhibited tumor growth by 68%; 0.45 mg/kg DDP + 30 mg/kg 9-cis RA inhibited growth by 78%. These decreases were greater than those that would have been produced by either agent summed separately. Of importance, at doses of 9-cis RA that enhanced DDP cytotoxicity, no change in dose tolerance was observed as compared to tolerances observed for either agent alone, indicating that 9-cis RA increased sensitivity to DDP without altering systemic toxicity. In addition, 9-cis RA profoundly altered squamous cell carcinoma phenotypes by suppressing squamous cell differentiation, resulting in tumors with increased numbers of basal cells. In contrast, DDP selectively depleted proliferating basal cells from carcinomas. In combination, morphological changes produced by 9-cis RA alone predominated, suggesting a possible basis for enhanced DDP sensitivity in tumors exposed to both agents. These data demonstrate that 9-cis RA enhances tumor sensitivity to DDP, and suggest that this combination should be tested in Phase I-II clinical trials for its potential for improving anticancer therapy of squamous cell cancers.

Topics: Alitretinoin; Animals; Antineoplastic Combined Chemotherapy Protocols; Bromodeoxyuridine; Carcinoma, Squamous Cell; Cisplatin; Female; Humans; Mice; Mice, Nude; Mouth Neoplasms; Neoplasm Transplantation; Receptors, Retinoic Acid; Retinoid X Receptors; Transcription Factors; Transplantation, Heterologous; Tretinoin

Nuclear retinoic acid receptor beta (RAR-beta) expression decreases in human premalignant oral lesions (POLs). RAR-beta suppression could result from a decrease in the cellular level of retinoids because RAR-beta gene transcription is enhanced by retinoids. To explore this hypothesis, we compared the binding of a monoclonal antibody (mAb) against all-transretinoic acid (RA; anti-RA mAbs) to normal oral tissue and POLs. All 7 normal specimens stained positive with the antibody compared to only 20 of 43 POLs; similarly, 7 of 7 normal specimens contained RAR-beta mRNA compared to only 14 of 43 POLs. Twenty-four specimens were available before and after a 3-month treatment with 13-cis-RA in vivo. Anti-RA mAb binding to these specimens increased from 10 of 24 before to 22 of 24 after treatment, and the expression of RAR-beta mRNA increased from 7 of 24 before to 21 of 24 after treatment, respectively. There was a strong agreement between the binding of anti-RA mAbs and the expression of RAR-beta. Thus, we propose that the binding of anti-RA mAbs reflects the level of retinoids in the tissues and that this level is related strongly to RAR-beta expression.

Topics: Antibodies, Monoclonal; Humans; Isotretinoin; Mouth Mucosa; Mouth Neoplasms; Precancerous Conditions; Receptors, Retinoic Acid; RNA, Messenger; Tretinoin

The effect of 13-cis-retinoic acid (cRA) and all-trans-retinoic acid (tRA) used alone or in combination with interferon alpha-2a (alpha-IFN 2a) was tested on three established human cell lines: KB (epidermoid carcinoma of the oral cavity), SCC-25 (tongue squamous cell carcinoma) and MCF-7 (mammary carcinoma). Both retinoids significantly decreased cell proliferation (growth curves) and colony forming efficiency (CFE) in all cell lines, in a dose-dependent way (at a concentration ranging from 10(-5) to 10(-9) M) and differing from line to line, following the pattern: MCF-7 > SCC-25 > KB. Retinoids at any concentration (already at 10(-7) M) combined with alpha-IFN 2a (ranging from 100 to 500 IU/ml) were more effective in inhibiting cell proliferation than each of the two compounds alone. This was particularly evident with SCC-25 cells. Concerning MCF-7 cells, on the contrary, the effects produced by the association suggested a possible additive more than synergistic amplification of growth inhibition.

Topics: Breast Neoplasms; Carcinoma, Squamous Cell; Cell Division; Drug Screening Assays, Antitumor; Drug Synergism; Humans; Interferon-alpha; Isotretinoin; Mouth Neoplasms; Tretinoin; Tumor Cells, Cultured

A 44-year-old woman was diagnosed as having acute promyelocytic leukemia (APL) in April 1988. On her first admission, chromosomal translocation (15; 17), +8, and +12 was detected. When she was readmitted to our hospital with the second relapse in May 1990, t(3; 13) and +8 was detected, instead of t(15;17). Complete remission was re-achieved with VP-16, MIT, and BHAC, but the third relapse occurred in September 1990. After obtaining informed consent, she was given etretinate 40 mg per day orally for 17 days, without any effect on leukemia. She was then given all-trans retinoic acid (ATRA) 60 mg per day orally for 29 days. Although a mild granulocytic recovery was observed, no sufficient hematological recovery was obtained (minor response). Besides common side effects of ATRA, such as dry skin and hypertriglycedemia, she had a myeloblastoma in the oral cavity, but it is unknown whether the symptom was a complication of ATRA therapy or not.

Topics: Administration, Oral; Adult; Blast Crisis; Female; Humans; Leukemia, Promyelocytic, Acute; Mouth Neoplasms; Tretinoin

Humoral hypercalcemia of malignancy is a paraneoplastic syndrome associated with a variety of solid neoplasms including squamous cell carcinomas of various sites. Parathyroid hormone-related protein (PTHrP) is a newly recognized hormone that has been implicated as one of the major causative factors in the pathogenesis of this syndrome. A canine oral squamous carcinoma cell line (SCC 2/88) was used to investigate the regulation of production of PTHrP in response to agents that alter keratinocyte differentiation/proliferation in vitro.. SCC 2/88 cells grown in serum-free media were exposed to various factors and PTHrP production was measured by radioimmunoassay. This cell line spontaneously produced substantial amounts of PTHrP (up to 7,000 pg/ml) without the need for a fibroblast-feeder layer. Production of PTHrP decreased at cellular confluence, and with increasing passage number.. Epidermal growth factor, cholera toxin, calcium, 1,25-dihydroxyvitamin D, ionomycin, trans-retinoic acid, transforming growth factor-beta 1 and hydrocortisone stimulated production of PTHrP by SCC 2/88 cells to various degrees. Transforming growth factor-beta 1 was the most potent stimulator of PTHrP production, with a maximal stimulation of 25-fold over control. Monensin decreased PTHrP secretion as early as 6 hours post-treatment and by 48 hours, there was no detectable PTHrP in the conditioned cell culture medium. Calcium, cholera toxin, ionomycin, and transforming growth factor-beta 1 decreased keratinocyte proliferation as measured by cell counts at all doses tested.. The results of this study revealed that SCC 2/88 cells spontaneously produced substantial amounts of PTHrP under baseline conditions and that compounds known to affect keratinocyte differentiation/proliferation up-regulated production of PTHrP. These cells will be valuable to investigate the molecular regulation of PTHrP production by squamous cell carcinomas.

Topics: Animals; Calcitriol; Calcium; Carcinoma, Squamous Cell; Cell Differentiation; Cell Division; Cell Line; Cholera Toxin; Dog Diseases; Dogs; Dose-Response Relationship, Drug; Epidermal Growth Factor; Humans; Hydrocortisone; Ionomycin; Keratinocytes; Kinetics; Mouth Neoplasms; Neoplasm Proteins; Parathyroid Hormone-Related Protein; Protein Biosynthesis; Radioimmunoassay; Time Factors; Transforming Growth Factor beta; Tretinoin; Tumor Cells, Cultured

The A9 antigen is a basement membrane antigen of normal squamous epithelial cells that is strongly expressed in many squamous carcinomas. High expression of this antigen is associated with early relapse in squamous cell carcinomas of the head and neck. We now know that the A9 antigen is structurally, immunologically, and functionally similar to the alpha 6 beta 4 integrin that has been shown to be linked to metastatic behavior in murine tumor models. The alpha 6 and beta 4 genes have been cloned and sequenced, and a model has been constructed from the deduced amino acid composition. In this study we present a hypothetical model and use it to design experiments to assess the factors that influence the expression of the A9/alpha 6 beta 4 integrin in normal and malignant keratinocytes. High calcium induces down regulation of A9/alpha 6 beta 4 antigen in normal but not malignant keratinocytes within 24 hours. Although calcium can down-regulate beta 4 message in tumor cells in the absence of epidermal growth factor (EGF), transcription of beta 4 increased in the tumor cells under the conditions we used for assessing antigen expression (calcium plus EGF). Retinoic acid also stimulated transcription of beta 4 in tumor cells, but this was partially inhibited by the presence of high calcium. Phosphorylation of the beta 4 chain was stimulated by epidermal growth factor and calcium in normal keratinocytes, but in the malignant cells phosphorylation was constant regardless of the culture conditions. Our results indicate that high expression of the alpha 6 beta 4 integrin is associated with conditions that favor migration and undifferentiated proliferation of normal keratinocytes and that malignant keratinocytes differ from normal keratinocytes by constitutive phosphorylation of beta 4 and by failure to downregulate beta 4 transcription in response to calcium in the presence of EGF.

Topics: Antigens, Neoplasm; Blotting, Northern; Calcium; Carcinoma, Squamous Cell; Cell Division; Epidermal Growth Factor; Humans; Integrins; Keratinocytes; Models, Molecular; Mouth Neoplasms; Phosphorylation; Proteolipids; Pulmonary Surfactant-Associated Proteins; Pulmonary Surfactants; RNA, Messenger; Transcription, Genetic; Tretinoin; Tumor Cells, Cultured

Cultured epidermoid oral carcinoma cells KB were easily detached from plastic surface in an ethylene diamine tetra acetic acid (EDTA) mediated detachment assay. Treatment of KB cells with retinol (vitamin A) or retinoic acid (RA) induced growth inhibition and caused reversible enhanced adhesion to the substratum in a similar fashion as well. Different synthetic retinoids were tested for their ability to induce growth inhibition and adhesion. A relationship between structure and activity of retinoids was found to exist. Possible mechanisms of retinoid-induced enhanced adhesion are discussed.

Topics: Carcinoma, Squamous Cell; Cell Adhesion; Cell Division; Culture Media; Humans; KB Cells; Kinetics; Mouth Neoplasms; Retinoids; Time Factors; Tretinoin; Tumor Cells, Cultured; Vitamin A

The purpose of this paper is to observe the blocking effect of topically subepithelial injected drug and Vit A acid painting on chemically induced oral precancerous lesion and to prove, on a certain extent, the hypothesis that subepithelial connective tissue could exert great influence on the differentiation of the epithelium. A total of 49 syrian hamster was used as experimental animal. Both buccal pouches of all animals were painted thrice weekly with 0.5% DMBA in acetone for 6 weeks. Then, they were divided into two groups: Control group and Experimental group. In the latter group, 70.8% precancerous lesions turned into normal epithelial tissue, whereas those untreated animals developed carcinoma by 62%.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Antineoplastic Agents; Cheek; Cricetinae; Epithelium; Injections; Mesocricetus; Mouth Neoplasms; Precancerous Conditions; Thiazoles; Thiazolidines; Tretinoin

The hamster cheek pouch (HCP) serves as an excellent model system not only for the studies on initiation and promotion but also for the modulation of experimental oral carcinogenesis. In our studies, HCPs treated with 7,12-dimethylbenz[a]anthracene (DMBA) showed both cheek pouch and stomach papillomas. Utilizing this model system, we tested and compared the modulatory effects of snuff, retinoic acid, and beta-carotene on the incidence of tumors and the keratin expression pattern. HCPs treated with snuff, either alone or in combination with DMBA, resulted in stomach papillomas. HCPs treated with snuff showed no cheek pouch tumors, and those treated with snuff and DMBA showed only 10-15% tumor incidence. Both beta-carotene and retinoic acid showed a total inhibition of DMBA-induced carcinogenesis in the HCP as well as in the stomach. The keratin expression pattern showed alterations depending on the experimental conditions.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; beta Carotene; Carotenoids; Cheek; Cricetinae; Keratins; Male; Mesocricetus; Mouth Neoplasms; Plants, Toxic; Tobacco, Smokeless; Tretinoin

Vitamin A and some of its metabolites such as beta-all-trans retinoic acid (RA) have been implicated in the regulation of differentiation of normal and malignant epithelial cells in vivo and in vitro. In the present study the effects of RA on the growth and differentiation of 7 cell lines derived from human head and neck squamous-cell carcinomas (HNSCCs) were examined. RA (greater than 0.01 microM) inhibited the proliferation in monolayer culture of 6 of 7 HNSCC cell lines. One cell line (UMSCC-35) was very sensitive, 5 (UMSCC-10A, -19, -30, -22B and HNSCC 1483) were moderately sensitive, and 1 (HNSCC 183) was insensitive. Three of the cell lines (UMSCC-22B, -30, and HNSCC 1483) were capable of forming colonies in semisolid medium--a capability that was suppressed by RA. The HNSCC cell lines expressed various levels of the squamous-cell differentiation markers type I (particulate, epidermal) transglutaminase (TGase) and cholesterol sulfate (CS). RA treatment (I microM, 6 days) decreased TGase activity by more than 50% in 3 (UMSCC-10A, -22B and 1483) of the 7 cell lines, and the effect on UMSCC-22B was dose-dependent. Type II TGase (soluble, tissue type) activity was detected in 3 cell lines, and after RA treatment its activity increased in HNSCC 1483 and 183 cells and decreased in UMSCC-19. Following RA treatment, CS levels decreased by 20, 25, 70, 76, 89 and 91% in cell lines UMSCC-30, -10A, 183, UMSCC-35, -22B, and HNSCC 1483, respectively. The suppression by RA of CS accumulation in the 1483 cells was dose-dependent. Cholesterol sulfotransferase activity, which is responsible for CS synthesis, was suppressed by 40-97% after RA treatment of UMSCC-19, -22B, and HNSCC 1483. Our results demonstrate that RA inhibits the growth and decreases the level of 2 squamous differentiation markers in HNSCC cells.

Topics: Carcinoma, Squamous Cell; Cell Line; Cell Transformation, Neoplastic; Cholesterol Esters; Depression, Chemical; Dose-Response Relationship, Drug; Head and Neck Neoplasms; Humans; Mouth Neoplasms; Sulfotransferases; Transglutaminases; Tretinoin; Tumor Cells, Cultured

Topics: Administration, Buccal; Animals; Cricetinae; Female; Male; Mesocricetus; Mouth Neoplasms; Precancerous Conditions; Tretinoin

Tumorigenesis requires accelerated polyamine biosynthesis, and elevated levels of ornithine decarboxylase, the rate-limiting enzyme in this reaction chain. The primary goal of this study was to determine whether induction of oral cavity carcinoma by dimethylbenzanthracene was accompanied by increased ornithine decarboxylase. It has previously been demonstrated in an oral carcinogenesis model that cotreatment with vitamins A or E delayed tumor development. The second goal of this study was to determine whether this chemoprotective effect was associated with a decrease in ornithine decarboxylase activity. We found that dimethylbenzanthracene did stimulate ornithine decarboxylase. Vitamins A and E alone also stimulate ornithine decarboxylase, and this effect is additive with dimethylbenzanthracene. Use of both vitamins together prevents the additive effect of either, alone, and vitamin A inhibits the late-phase ornithine decarboxylase response to dimethylbenzanthracene in all animals. We conclude that pretreatment with vitamins A, or A and E together protects against the carcinogenic action of dimethylbenzanthracene, and that the mechanism of this protection is early truncation of the ornithine decarboxylase response to dimethylbenzanthracene.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Carcinoma, Squamous Cell; Cheek; Cricetinae; Male; Mesocricetus; Mouth Neoplasms; Ornithine Decarboxylase Inhibitors; Premedication; Tretinoin; Vitamin A; Vitamin E

The present study reports light and electron microscopic observations of hamster cheek pouch epithelium exposed to 25 micrograms DMBA (DMBA = 9,10 Dimethyl, 1,2 Benz(a)-nthracene, RA = Retinoic Acid) and 25 micrograms DMBA along with 25 micrograms, 50 micrograms and 100 micrograms retinoic acid. Significant delay in tumour induction was observed in the animals treated with DMBA + retinoic acid. DMBA + retinoic acid treated cheek pouch developed papillary epidermoid carcinomas which were less invasive and less keratinized than only DMBA treated animals. At cellular level DMBA treated animals showed keratinized cells with thick bundles of tonofilaments, broken basement membrane, wide intercellular spaces and loss of desmosomal attachments, whereas animals treated with DMBA + retinoic acid showed decrease in the intercellular spaces, maintenance of basement membrane and intracellular organelles with suppression of keratinization, indicating the differentiating effect of retinoic acid on DMBA transformed cells of hamster cheek pouch.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Carcinoma, Papillary; Carcinoma, Squamous Cell; Cell Nucleus; Cell Transformation, Neoplastic; Cheek; Cricetinae; Cytoplasm; Epithelium; Female; Male; Mesocricetus; Microscopy, Electron; Mouth Mucosa; Mouth Neoplasms; Neoplasm Invasiveness; Tretinoin

Topics: Animals; Antineoplastic Agents; Cricetinae; Drugs, Chinese Herbal; Female; Male; Mesocricetus; Mice; Mice, Inbred BALB C; Mice, Nude; Mouth Mucosa; Mouth Neoplasms; Neoplasm Transplantation; Precancerous Conditions; Thiazoles; Thiazolidines; Tretinoin

Regression of established hamster buccal pouch carcinoma has recently been demonstrated in association with an induction of tumor necrosis factor alpha in macrophages. Regression of hamster buccal pouch tumors has also been demonstrated following the local injection of alphatocopherol, canthaxanthin and an extract of Spirulina-Dunaliella algae. The current study demonstrates that cancer regression is also accompanied by a significant induction of tumor necrosis factor in macrophages in the tumor area, suggesting a possible mechanism of tumor destruction. One hundred and forty young, male adult hamsters were divided into seven equal groups of 20 animals. Epidermoid carcinomas were induced in right buccal pouches by 14 weeks of painting, three times per week, of a 0.5% solution of 7,12-dimethylbenz(a)anthracene. Groups 1 and 2 were untreated and sham injected controls. Groups 3-7 had injected twice weekly into the right buccal pouches 0.1 ml (1.9 mg/ml of 13-cis-retinoic acid, canthaxanthin, algae extract, beta-carotene and alphatocopherol. After 4 weeks the tumors in groups 3-7 demonstrated varying degrees of regression and the animals were sacrificed and the right buccal pouches excised. Tumor necrosis factor alpha (TNF-alpha) was demonstrated by immunohistochemical techniques. A very significant increase in TNF-alpha positive macrophages was found in the tumor-bearing pouches of animals in groups 5-7. Smaller numbers of TNF-alpha-positive macrophages were found in group 4 pouches and a very slight increase in group 3 pouches.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Canthaxanthin; Carcinoma, Squamous Cell; Carotenoids; Cheek; Cricetinae; Eukaryota; Macrophages; Male; Mesocricetus; Mouth Neoplasms; Tretinoin; Tumor Necrosis Factor-alpha; Vitamin E

The effect of algae extract on tumor regression was studied. Phycotene (extract of Spirulina and Dunaliella algae) 250 micrograms in 0.1 ml MEM (minimum essential medium) was injected locally into DMBA (7, 12 dimethylbenz(a)anthracene)-induced squamous cell carcinomas of hamster buccal pouch in 20 animals. DMBA-induced carcinomas in 20 hamsters were injected locally with beta carotene 250 micrograms in 0.1 ml MEM; DMBA-induced carcinomas in 20 animals were injected locally with canthaxanthin, 250 micrograms in 0.1 ml MEM, and DMBA-induced carcinomas in 20 animals were injected locally with 13-cis-retinoic acid, 250 micrograms in 0.1 ml MEM. Twenty animals with DMBA-induced carcinomas were sham-injected controls using 0.1 ml MEM. The various agents were injected into the tumor bearing right buccal pouches twice-weekly for four weeks. Total tumor regression was found in 30% of phycotene animals, 20% of beta carotene animals and 15% of canthaxanthin animals after four weeks. Partial tumor regression was found in the remaining 70% of phycotene animals, 80% of beta carotene animals and 85% of canthaxanthin animals. None of the 13-cis-retinoic acid animals had total tumor regression, but 70% showed partial regression. No tumor regression was found in the DMBA control group and the sham-injected group.

Topics: Animals; Canthaxanthin; Carcinoma, Squamous Cell; Carotenoids; Chlorophyta; Cricetinae; Cyanobacteria; Isotretinoin; Male; Mesocricetus; Mouth Mucosa; Mouth Neoplasms; Neoplasms, Multiple Primary; Plant Extracts; Remission Induction; Tretinoin; Vitamin E

Physiologic concentrations (5 X 10(-8) M) of all-trans-retinoic acid (RA) caused a 2- to 3-fold increase in the rate of cell desquamation of a malignant keratinocyte line (SqCC/Y1) grown in serum-free medium. Measurement of the incorporation of [35S]sulfate and [3H]glucosamine into cetylpyridinium chloride-precipitable glycosaminoglycans (GAGS) demonstrated that RA treatment did not alter total GAG production. In addition, compartmental distribution was not affected by RA, with 50-70% of GAGS being recovered from the medium, 25% from the pericellular matrix, and the remainder from the cells. Relatively small amounts of GAGS were associated with shed cells in RA-treated cultures, presumably reflecting a relatively short association of these cells with the monolayer before desquamation. Chondroitin sulfate (Ch-S), heparin/heparan sulfate (Hep-S), and hyaluronic acid (HA) were the GAG species identified in SqCC/Y1 cultures by gel-exclusion chromatography. RA reduced the relative amount of HA in the trypsin-sensitive pericellular compartment by 50%. Since the proportions of Ch-S and Hep-S were not affected by RA, the findings suggest that the altered ratio of HA to sulfated GAGS in this fraction may contribute to the increased cell desquamation. Hydrocortisone (10(-6) M) reversed the effect of RA on cell shedding, and increased the proportion of pericellular HA relative to that found in cultures exposed to RA alone. These findings support the concept that the relative proportion of HA to sulfated GAGS may be important in the intercellular cohesion of keratinocytes. In addition, the relative decrease in HA and the predominance of Ch-S over Hep-S in SqCC/Y1 cultures differed from results reported with normal keratinocytes, indicating that this property may be associated with the malignant phenotype.

Topics: Carcinoma, Squamous Cell; Cell Line; Cheek; Glycosaminoglycans; Humans; Hydrocortisone; Mouth Mucosa; Mouth Neoplasms; Neoplasms, Experimental; Skin; Tretinoin

After in vitro incubation of human squamous cell carcinomas of the head and neck region with aromatic retinoid an increased number of lysosomes can be observed in the tumor cells. It is discussed whether this accumulaion of lysosomes is due to a direct stimulation of lysosomal enzyme synthesis or whether it is consequence of cell damage by the retinoid.

Topics: Acid Phosphatase; Acitretin; Carcinoma, Squamous Cell; Culture Techniques; Dose-Response Relationship, Drug; Humans; Laryngeal Neoplasms; Lysosomes; Mouth Neoplasms; Tretinoin

Epidermoid carcinomas of the oral cavity and oropharynx from six patients were examined for the presence and amount of cellular retinol (CRBP) and cellular retinoic acid-binding (CRABP) proteins. In all cases adjacent, grossly normal tissue was similarly examined. For each example CRBP levels were significantly higher in tumor tissue compared to adjacent tissue. In four cases CRABP was significantly higher. This is of interest because retinol, retinoic acid and their analogs have been shown to inhibit the development of various epithelial tumors, and this inhibition is possibly mediated by these binding proteins.

Topics: Carcinoma, Squamous Cell; Carrier Proteins; Centrifugation, Density Gradient; Female; Humans; Male; Mouth Neoplasms; Oropharynx; Pharyngeal Neoplasms; Receptors, Retinoic Acid; Retinol-Binding Proteins; Retinol-Binding Proteins, Cellular; Tretinoin; Vitamin A

In order to determine whether 13-cis-retinoic acid, an analog of vitamin A, has antitumor activity in an oral cancer model system, the following study was undertaken. Fifty-three adult hamsters were divided into four groups. Group 1 was tested with a 0.5 percent solution of 9,10-dimethyl-1,2-benzanthracene (DMBA) in heavy mineral oil, which was painted on the right buccal pouch three times per week for 12 weeks. Group 2 received DMBA plus 13-cis-retinoic acid (RA) incorporated into gelatinized beadlets and mixed with a powdered commercial diet (dosage, 300 mg per kilogram of diet). Group 3 received only RA; Group 4 received a placebo. The animals were killed at 6, 12, and 18 weeks and tissues were studied clinically and histologically in a routine manner. Results show that all groups receiving DMBA developed epidermoid carcinomas. However, there were several other changes. In the RA-treated animals, particularly those treated with DMBA, there was an ingrowth of surface epithelium with development of ductal structures in the buccal pouch. There were changes in surface epithelium, and there were dense aggregates of lymphoid tissue with development of exophytic nodules suggestive of lymphoma. Animals fed RA showed a relative weight loss. The findings suggest that there was a hypervitaminosis A state yielding prominent epithelial metaplastic changes but not affecting the progression or production of carcinoma.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Benz(a)Anthracenes; Carcinoma, Squamous Cell; Cheek; Cricetinae; Female; Isotretinoin; Male; Mesocricetus; Mouth Neoplasms; Neoplasms, Experimental; Tretinoin

Sixty-four male and female Syrian hamsters, 3 months of age and weighing 90 to 120 grams, were divided into four equal experimental groups. In animals of Groups 1 and 2 the left buccal pouch was painted three times weekly with a 0.5% solution of DMBA in heavy mineral oil. Group 2 animals also received 10 mg. of 13-cis-retinoic acid in peanut oil administered orally twice a week by pipette. Carcinogen retinoid were administered on alternate days. Group 3 animals served as controls, receiving only 13-cis-retinoic acid. Group 4 animals served as untreated controls. Four animals in each group (two males and two females) were killed at 10, 12, 14, and 16 weeks. The Group 2 animals, which received 13-cis-retinoic acid, exhibited a significant delay in DMBA carcinogenesis of buccal pouch mucosa, as studied both grossly and histologically. Both groups eventually demonstrated well-differentiated epidermoid carcinomas, but the tumors were smaller in the DMBA-retinoid animals.

Topics: Animals; Carcinoma, Papillary; Carcinoma, Squamous Cell; Cheek; Cricetinae; Female; Isotretinoin; Keratosis; Leukoplakia, Oral; Male; Mesocricetus; Mouth Mucosa; Mouth Neoplasms; Neoplasms, Experimental; Tretinoin

Animal studies have shown. a) an association between vitamin A and cancers of epithelial origin, and b) that vitamin A and its analogues delay tumour appearance, retard tumour growth and regress tumours induced by carcinogenic polycyclic aromatic hydrocarbons. Human epidemiological and biochemical studies suggest that cancers of epithelial origin may be associated with vitamin A deficiency. Vitamin A and its analogues may have a prophylactic and a therapeutic role in cancers of epithelial origin.

Topics: Animals; Bronchial Neoplasms; Carcinoma, Squamous Cell; Cell Transformation, Neoplastic; Humans; Lung Neoplasms; Mouth Neoplasms; Neoplasms, Experimental; Pharyngeal Neoplasms; Tretinoin; Vitamin A; Vitamin A Deficiency

Leukoplakia is neither a clinical, aetiological nor histopathological entity. Therefore treatment is difficult particularly in multifocal and advanced lesions. Since 1970, we have tested the therapeutic effect of different derivatives of all-trans-retinoic acid. The study includes 75 cases with homogeneous leukoplakia without or with minimal epithelial dysplasia. Over 60% of the cases treated showed positive early results. In follow-ups from 1 to 6 years about 45% of cases showed complete or partial remission. The rest showed relapses or even progression. In cases with recurrence without changes in the morphological characteristics, positive effects were achieved with 1 to 4 repeated courses of therapy. All derivatives of retinoic acid tested so far have shown undesirable side effects with systematic manifestations or local symptoms: interruption of treatment (4) or reduction of dosage (9) were unavoidable for that reason. Regarding the side effects, retinoic acid should only be given under clinical supervision. Of the derivates tested to date, aromatic retinoid seems to have the best curative potential in homogenic leukoplakia.

Topics: Humans; Leukoplakia, Oral; Mouth Neoplasms; Precancerous Conditions; Recurrence; Tretinoin; Vitamin A

15 patients with superficial basaliomas or premalignant epithelial neoplastic disorders (actinic keratosis, leukoplakia, Bowen's disease) were treated locally over three weeks with retinoic acid (RA) alone or in combination with 5-fluorouracil (5-FU). In 11 cases the lesions disappeared clinically, however, only 5 patients proved to be cured by histological examination. 4 of them were treated with RA combined with 5-FU. There was a decrease of the 3H-index after the first week and an increase after the third week of treatment. These findings suggest, that RA inhibits the proliferation of neoplastic keratinocytes and stimulates the proliferation of normal epidermal cells. Retinoic acid, therefore, has an inhibitory effect on epithelial neoplasias, particularly in combination with 5-FU. Since local therapy with RA and 5-FU is not sufficient for routine clinical purposes in all cases, their use should be restricted to selected patients.

Topics: Aged; Carcinoma, Basal Cell; Drug Therapy, Combination; Female; Fluorouracil; Humans; Keratosis; Leukoplakia; Light; Lip Neoplasms; Male; Middle Aged; Mouth Neoplasms; Neoplasms, Radiation-Induced; Precancerous Conditions; Scalp; Skin Neoplasms; Thorax; Tretinoin; Vitamin A