tretinoin and retinamide

Topics: Animals; Etretinate; Humans; Retinoids; Tretinoin; Vitamin A

There are strong data showing that increased breast cancer risk is associated with increased mammographic density. Tamoxifen has been shown to decrease the risk of invasive breast cancer and decrease breast density. We sought to demonstrate and calculate the extent of change in mammographic density in women who have taken tamoxifen for up to 2 years. We evaluated mammograms from 28 high-risk women who were taking tamoxifen. Four different methods of evaluation were used: (a) two qualitative methods (Wolfe criteria and the American College of Radiology Breast Imaging and Reporting Data System criteria); (b) one semiquantitative method (mammograms were assigned one of five semiquantitative scores by visual inspection); and (c) one quantitative method (computer-aided calculation of fibroglandular area from digitized mammograms). The Wolfe criteria showed a 0.03 category decrease per year (P = 0.50). The American College of Radiology Breast Imaging and Reporting Data System criteria showed a 0.1 category decrease per year (P = 0.12). Semiquantitative criteria showed a 0.2 category decrease per year (P = 0.039). Digitized scores showed a 4.3% decrease per year (P = 0.0007). In conclusion, tamoxifen causes a decrease in mammographic density with use, an effect that is better quantitated with semiquantitative criteria or digitized images. Density change might become useful as a surrogate end point for the effect of tamoxifen and other chemopreventive measures, although our data do not predict an individual's degree of risk reduction.

Topics: Adult; Age Factors; Aged; Anticarcinogenic Agents; Antineoplastic Agents; Biomarkers, Tumor; Breast; Breast Neoplasms; Carcinoma in Situ; Carcinoma, Ductal, Breast; Carcinoma, Lobular; Feasibility Studies; Female; Humans; Mammography; Middle Aged; Pilot Projects; Postmenopause; Radiographic Image Enhancement; Reproducibility of Results; Selective Estrogen Receptor Modulators; Tamoxifen; Tretinoin

Surrogate end point biomarkers for risk assessment and efficacy of potential chemopreventive agents are needed to improve the efficiency and reduce the cost of chemoprevention trials. It is imperative to develop the best clinical breast model for translational surrogate end point biomarker studies, especially with respect to accrual feasibility. We have initiated a prospective study to develop biomarkers for tamoxifen and N-[4-hydroxyphenyl] retinamide by administering either a placebo or both drugs for 2-4 weeks to women with ductal carcinoma in situ or early invasive cancers in the interval between the initial diagnostic core biopsy and definitive surgery. The principle end point is pretreatment versus posttreatment tumor levels of Ki-67; a number of other exploratory markers will also be examined. The planned target sample size is 100 patients. Between February 1997 and February 2000, 4514 women who had either an abnormal mammogram or a diagnosed breast cancer were screened for the study. Of these 4514 screened patients, 52 (1%) were registered on the study. Major factors of nonparticipation in the remaining 4462 women were as follows: (a) no evidence of malignancy (2081 patients; 46%); (b) ineligible per protocol criteria (575 patients; 13%); (c) preoperative chemotherapy/tamoxifen (520 patients; 11%); (d) surgery scheduling conflict (360 patients; 8%); (e) outside needle biopsy (221 patients; 5%); (f) no residual disease after excisional biopsy (345 patients; 8%); and (g) second opinion only (123 patients; 3%). Other nonparticipation factors included fine needle aspiration only, refusal, tumor size > 2 cm, and estrogen replacement therapy (35 patients each; 2% each). The protocol was amended in midstudy to allow outside needle biopsy, tumor > 2 cm, and estrogen replacement therapy. Accrual to biomarker (nontherapeutic) protocols with delay in definitive cancer surgery is challenging but feasible. Although some accrual problems remain, we have nonetheless succeeded in recruiting 50% of our target sample size in a 3-year period.

Topics: Adult; Aged; Anticarcinogenic Agents; Antineoplastic Agents; Antineoplastic Agents, Hormonal; Biomarkers, Tumor; Breast Neoplasms; Carcinoma, Intraductal, Noninfiltrating; Female; Humans; Middle Aged; Patient Selection; Prospective Studies; Research Design; Risk Assessment; Sensitivity and Specificity; Tamoxifen; Tretinoin

To report long term therapeutic effect in patients with esophageal pre-cancerous lesions in high-risk area of esophageal cancer.. The therapeutic trial enrolled 2,531 cases of severe dysplasia and 3,393 cases of mild dysplasia. A 2-arm randomized, placebo-controlled design was used in which the participants received Zeng Sheng Ping (ZSP, an herbal composite), retinamide or placebo for cases with severe dysplasia and riboflavin or placebo for those with mild dysplasia.. Treatment with ZSP and retinamide decreased malignant transformation rate of severe dysplasia by 52.2% and 43.2%, respectively after 5 years of treatment. When the treatment had been discontinued for 4 years, the rate of malignat transformation was decreased by 42.1% and 38.2% respectively, which remained significantly higher than that of the placebo-treated control. Riboflavin treatment was continued for 9 years. At the end of 5-year medication, the malignant transformation rate decreased by 34.8%, which was not significantly different from that of the placebo control. When the treatment was continued up to 9 years, the rate was further decreased to 37.0%, which became statistically significant.. ZSP, retinamide and riboflavin treatment can effectively prevent esophageal dysplasia from transforming into carcinoma.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Drugs, Chinese Herbal; Esophageal Neoplasms; Female; Humans; Male; Middle Aged; Precancerous Conditions; Tretinoin

Since 1983, a long-term clinical trial of esophageal carcinoma chemoprevention has been conducted in a high-risk area in China. From this study, 25 esophageal severe dysplasia patients without therapy were selected for analysis. After 5-year follow-ups, 14 cases progressed to esophageal carcinoma, while the other 11 cases remained stable. Three Papanicolaou's smears were used for each case, including one from the esophageal cytological examination at the beginning, two from the re-examinations three and five years later respectively. About 100 visually normal intermediate cells were randomly collected per slide by high resolution image analysis. More than 100 features (morphologic, densitometric, textural) were extracted. The classifications were made by means of stepwise linear discriminate analysis at the single cell level as on the specimen level using up to ten features. In all three comparisons of patients with progression and with regression at time of diagnosis, three years after diagnosis and five years later, the correct cell classification rates were about 70%. The subsequent specimen classifications by means of the a posteriori probability (APOP) distribution of the cells in each case led to 80% correct classification. All selected features reflected the chromatin structure of nuclei. The result demonstrated that the chromatin structures of esophageal epithelial cells in severely dysplasic patients are different between cases with and without progression. These results suggest the possibility of the application of image analysis in the clinical trials to find the dysplasia patients with higher risk of progression, in order to reduce the number of patients for therapy.

Topics: Adult; Aged; Antineoplastic Agents; Biomarkers, Tumor; Cell Nucleus; Chromatin; Cytodiagnosis; Drugs, Chinese Herbal; Esophageal Neoplasms; Esophagus; Humans; Image Processing, Computer-Assisted; Middle Aged; Prognosis; Prospective Studies; Time Factors; Tretinoin

Dysplasia of the uterine cervix is a recognized precancerous condition. Because of the observed ability of retinoids to suppress various cell lines in vitro, a number of clinical studies have examined the effect these agents have on cervical dysplasia, with the object of developing a means of chemoprevention of cervical malignancies in women at risk. Three cervical cancer chemoprevention trials with Retinamide II (RII) have been conducted at the Cancer Institute, Chinese Academy of Medical Sciences, Beijing, China. A pilot study used RII to intervene in cases of precancerous cervical dysplasia. Twenty-seven women with mild, moderate, or severe cervical dysplasia, pathologically confirmed, were treated by RII suppositories, 10 mg QD, given intravaginally for 6 months (each course lasting 3 months). The results indicated that after the second course, the overall response rate was 96.29% and the complete response rate was 88.89%. In general, side effects were mild. A little cervical and vaginal irritation was well tolerated. In the second double-blind study, patients with precancerous cervical lesions were randomized into two groups, one treated with RII suppository intravaginally and the other with a placebo, once daily for 50 days in two courses. Precancerous lesions in 68.76% of patients in the treatment arm disappeared, with an overall effective rate of 74.29% after two courses of treatment with RII. Its curative effect was approximately that of laser beam radiation and electrocautery (P > 0.05), and differed significantly (P < 0.01) from that of traditional antiinflammatories. RII can be a major measure in prevention and treatment of cervical cancer in high-incidence areas in China. In the third trial, we are conducting a randomized double-blind study placebo controlled, in a high-incidence area of cervical cancer (Xiang-Yuan county, Shang Xi Province, China). At present, the patients are being followed up and the study will be completed after 2 years.

Topics: Antineoplastic Agents; China; Double-Blind Method; Female; Humans; Incidence; Pilot Projects; Placebos; Precancerous Conditions; Tretinoin; Uterine Cervical Neoplasms

Inhibition of buccal pouch carcinogenesis induced by dimethyl-benzanthracene in hamsters with retinamide was studied. Group A received oral retinamide at a dosage of 20mg/kg, every day for eight weeks. Group B was treated by retinamide orally at the same dosage, plus topical treatment by retinamide. Group C was treated by retinamide topically for eight weeks. Experiments exhibited that under the action of retinamide the incidence of tumor was lowered significantly. All the Group A, B and C had a good response. Clinically 80 patients were randomly arranged into two groups. One group received placebo and served as controls and the other group was treated by retinamide. Results indicate that retinamide is effective against leukoplakia and the response rate is as high as 84.0%. By contrast, only 16.7% of patients receiving placebo showed some improvement.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Adult; Aged; Animals; Antineoplastic Agents; Cricetinae; Female; Humans; Leukoplakia, Oral; Male; Middle Aged; Tretinoin

The patients with cervical precancerous lesions were double-blindly randomized into two groups. The one was treated with retinamide II (RII) suppository intravaginally and the other with placebo, once daily for 50 days as a course. The results showed precancerous lesions in 68.57% of the patients disappeared, with an overall effective rate of 74.29% after two-course treatment with RII. Its long-term curative effect approximated to that with laser beam radiation and electrocautery (P > 0.05), and differed significantly (P < 0.01) from that with common antiphlogistic. So, RII can be used as a major measure in prevention and treatment for cervical cancer in high-incidence areas in our country.

Topics: Administration, Intravaginal; Double-Blind Method; Female; Follow-Up Studies; Humans; Suppositories; Tretinoin; Uterine Cervical Dysplasia; Uterine Cervical Neoplasms

Patients with cervical precancerous lesions were double blindly divided into 2 groups and treated with either Retinamide II (RII) or Riboflavin (VB2) suppository. The suppository containing RII 20mg or VB2 5mg was given intravaginally daily for 100 days, divided into 2 courses. Clinical examination, papanicolaou cytology and tissue biopsy under colposcope were carried out before and after treatment. The results showed that the disappearance rates of precancerous lesions (DRPL) after the second course of treatment with RII or VB2 were 68.5% and 52.00%, and the overall response rates were 74.29% and 56.0%, respectively. 1 or 2 yrs after treatment, DRPL of the RII, Riboflavin and laser groups did not show significant difference (P > 0.05). The statistically significant differences were among the RII, Riboflavin, laser groups and antiphlogistic treatment group (P < 0.01). The results indicate that local application of RII and Riboflavin may serve as chemopreventive agents for cervical cancer.

Topics: Administration, Intravaginal; Double-Blind Method; Female; Follow-Up Studies; Humans; Precancerous Conditions; Riboflavin; Suppositories; Tretinoin; Uterine Cervical Neoplasms

Since 1983, we have been conducting inhibitory therapy for precancerous lesions of the esophagus in two regions of Henan Province considered high-risk areas of esophageal carcinoma. Our goal was to effect a 50% reduction in the canceration rate of marked esophageal dysplasia. By means of a cytological survey, 2531 cases of marked esophageal dysplasia and 3393 cases of mild esophageal dysplasia were selected. The former were randomly divided into 3 groups for antitumor-B (ATB, a mixture of Chinese herbs), retinamide (4-ethoxycarbophenylretinamide) and placebo treatment respectively, and the latter into 2 groups treated with riboflavin and placebo respectively. Treatment was continued for 3 or 5 years (administration rate greater than 90% in all groups) and esophageal cytology reexamined (reexamination rates were 94.1% and 92.5% respectively). Our results were as follows: 1) ATB 3- and 5-year subjects saw the canceration rate of marked esophageal dysplasia drop by 52.2% and 47.3% respectively as compared to control (P less than 0.01). 2) Retinamide lowered the canceration rate by 37.3% after a 3-year treatment period, with this reduction reaching 43.2% after an additional 2 years of treatment with increased dosages (P less than 0.05, P less than 0.01). 3) In the riboflavin group, the canceration rate of mild esophageal dysplasia was reduced by 22.2% and 34.8% after 3 and 5 years of treatment respectively, but these differences were not statistically significant. The above results verify the efficacy of medicamentous inhibitory therapy for esophageal precancerous lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Aged; Drugs, Chinese Herbal; Esophageal Neoplasms; Female; Humans; Male; Middle Aged; Precancerous Conditions; Riboflavin; Tretinoin

9633 subjects aged 40 to 65 were sampled from high-risk areas for esophageal cancer and examined by esophageal exfoliative cytology. 2531 and 3393 cases of markedly and mildly dysplastic patients were screened out respectively. Those with marked dysplasia were randomized into 3 groups and given respective medications: antitumor B (Chinese herbs), 4-ethoxycarbophenylretinamide (retinamide) and placebo. The subjects with mild dysplasia were randomly divided into 2 groups for riboflavin and placebo treatment. After medication for 3 or 5 years the subjects were reexamined by esophageal exfoliative cytology. The incidence of esophageal cancer in the antitumor B group after taking medication for 3 and 5 years was reduced by 52.2% and 47.3% respectively as compared with the placebo group. These differences were statistically significant (chi 2 = 8.9115, P less than 0.01; chi 2 = 10.9573, P less than 0.01). The incidence of esophageal cancer in the retinamide group after 3 years of medication was reduced by 37.3% as compared with control, while the incidence among patients treated for 5 years dropped by 43.2% relative to control. This difference was statistically significant (chi 2 = 9.2836, P less than 0.01). The incidence of esophageal cancer in the riboflavin group was reduced by 22.2% and 34.8% respectively. The above results indicate that secondary prevention of esophageal cancer is possible and that inhibitory therapy of precancerous lesions of the esophagus is effective in preventing esophageal cancer. This method needs further trial and study in high risk areas of esophageal cancer. The reliability of the experimental results is critically discussed.

Topics: Adult; Aged; Antineoplastic Agents, Phytogenic; Drugs, Chinese Herbal; Esophageal Neoplasms; Female; Follow-Up Studies; Humans; Male; Middle Aged; Precancerous Conditions; Riboflavin; Tablets; Tretinoin

In 1983, intervention of precancerous lesion of esophagus was undertaken in the high risk area of esophageal cancer, Heshun Village, Linxian County. It had been expected that cancerous degeneration rate of esophageal dysplasia should be reduced by 50% so as the prevention of esophageal cancer could become possible. 6758 subjects of the general population aging from 40 to 65 were examined by esophageal exfoliative cytology, 1729 had marked dysplasia and 2411 had mild dysplasia of esophageal epithelium. Those with marked dysplasia were randomized into 3 groups to take their respective medication: antitumor B (Chinese herbs); retinamide (4-Ethoxycarbophenylretinamide) and placebo. The subjects with mild dysplasia were divided randomly into 2 groups for treatment by riboflavin and placebo. 95% of the subjects had taken 90% or more of the total medication for 3 years, at the end of which they were reexamined by esophageal exfoliative cytology. The reexamination rate was 94.1%. The incidence of esophageal cancer in the antitumor B group (3.9%) was reduced by 53% as compared with that of the placebo group (8.3%). This difference had statistical significant (means 2 = 7.672, P less than 0.05). The incidence of esophageal cancer in retinamide and riboflavin groups were reduced by 33.7% and 19% as compared with those of the control groups. The regression rate of dysplasia in the treatment groups were increased than that of the control groups. The above results showed that our hypothesis about the secondary prevention of esophageal cancer is correct. The intervention of precancerous lesion of the esophagus is effective in the prevention of esophageal cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Aged; Drugs, Chinese Herbal; Esophageal Neoplasms; Female; Humans; Hyperplasia; Male; Middle Aged; Precancerous Conditions; Riboflavin; Tretinoin

It is widely reported that

Topics: Animals; Antineoplastic Agents; Fenretinide; Mice; Rats; Tretinoin

Topics: Alternative Splicing; Animals; Antineoplastic Agents; Cell Line, Tumor; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic; Humans; Intracellular Signaling Peptides and Proteins; Male; Mice; Prostatic Neoplasms, Castration-Resistant; Protein Isoforms; Protein Serine-Threonine Kinases; Receptors, Androgen; RNA Interference; Signal Transduction; Tretinoin; Xenograft Model Antitumor Assays

Androgen receptor (AR) and MNK activated eIF4E signaling promotes the development and progression of prostate cancer (PCa). In this study, we report that our Novel Retinamides (NRs) target both AR signaling and eIF4E translation in androgen sensitive and castration resistant PCa cells via enhancing AR and MNK degradation through ubiquitin-proteasome pathway. Dual blockade of AR and MNK initiated eIF4E activation by NRs in turn induced cell cycle arrest, apoptosis, and inhibited cell proliferation. NRs also inhibited cell migration and invasion in metastatic cells. Importantly, the inhibitory effects of NRs on AR signaling, eIF4E translation initiation and subsequent oncogenic program were more potent than that observed with clinically relevant retinoids, established MNK inhibitors, and the FDA approved PCa drugs. Our findings provide the first preclinical evidence that simultaneous inhibition of AR and eIF4E activation is a novel and efficacious therapeutic approach for PCa, and that NRs hold significant promise for treatment of advanced prostate cancer.

Topics: Androgen Antagonists; Antineoplastic Agents; Apoptosis; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Movement; Cell Proliferation; Dose-Response Relationship, Drug; Eukaryotic Initiation Factor-4E; Gene Expression Regulation, Neoplastic; Humans; Intracellular Signaling Peptides and Proteins; Male; Neoplasms, Hormone-Dependent; Prostatic Neoplasms; Prostatic Neoplasms, Castration-Resistant; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Receptors, Androgen; RNA Interference; Signal Transduction; Time Factors; Transfection; Tretinoin

Owing to the pharmacological potential of ATRA (all trans-retinoic acid), a series of retinamides and a 1-(retinoyl)-1,3-dicyclohexylurea compound were prepared by reacting ATRA with long chain alkyl or alkenyl fatty amines by using a 4-demethylaminopyridine (DMAP)-catalyzed N,N¢-dicyclohexylcarbodiimide (DCC) coupling. The successful synthesis of the target compounds was demonstrated using a range of spectroscopic techniques. The cytotoxicity of the compounds was measured along with their ability to induce cell cycle arrest and apoptosis in human cancer cell lines MCF-7 (breast cancer) and HepG2 (liver cancer) and normal human cell line HEK293 (embryonic kidney). The results of cytotoxicity and flow cytometry data showed that the compounds had a moderate to strong effect against MCF-7 and HepG2 cells and were less toxic to HEK293 cells. N-oleyl-retinamide was found to be the most potent anticancer agent and was more effective against MCF-7 cells than HepG2 cells.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Cycle Checkpoints; Cell Line; Cell Line, Tumor; Female; HEK293 Cells; Hep G2 Cells; Humans; Liver Neoplasms; MCF-7 Cells; Tretinoin; Urea

The present study was performed to investigate the effect of retinoic acid amide (RAA) on the expression of integrin α3β1, rate of cell proliferation and migration in p53-deficient glioma cell line, LN-308. The results revealed promotion of integrin α3 expression, reduction in proliferation and migration in RAA treated cells compared to the control LN-308 glioma cells. Promotion of RAA induced integrin α3β1 expression led to the enhancement in cyclin-dependent kinase nuclear localization and activation of Akt pathway. In addition, RAA treatment inhibited the expression of nuclear factor-κB, Bcl-2 and epidermal growth factor receptor (EGFR). These factors are responsible for promoting the rate of cell proliferation and survival in the carcinoma cells. Thus RAA treatment inhibits rate of LN-308 glioma cell proliferation and migration through increase in integrin α3β1 expression and activation of Akt pathway. Therefore, RAA can be of therapeutic importance for the treatment of glioma.

Topics: Antineoplastic Agents; Brain Neoplasms; Cell Cycle Proteins; Cell Line, Tumor; Cell Movement; Cell Proliferation; Enzyme Activation; ErbB Receptors; Gene Expression Regulation, Neoplastic; Glioma; Humans; Integrin alpha3beta1; Neoplasm Invasiveness; NF-kappa B; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; RNA Interference; Signal Transduction; Time Factors; Transfection; Tretinoin

Tyrosinase is involved in the synthesis of melanin in the skin and hair as well as neuromelanin in the brain. This rate limiting enzyme catalyzes two critical steps (reactions) in melanogenesis; the hydroxylation of tyrosine to form DOPA and the subsequent oxidation of DOPA into dopaquinone. Several new aminophenol derivatives have been synthesized based on structure-activity relationship studies of N-(4-hydroxyphenyl)retinamide (1), a derivative of retinoic acid. In order to find new tyrosinase inhibitors, we investigated the effects of these p-aminophenols, including p-decylaminophenol (3), on the activity of mushroom tyrosinase. Compound 3 was the most potent agent, showing significant inhibition as compared with control. The inhibitory effects of 3 on tyrosinase activities were greater than seen with kojic acid, a well-known potent inhibitor of tyrosinase activity, which also causes adverse effects, including rash and dermatitis. A Lineweaver-Burk kinetic analysis of inhibition showed that 3 suppresses tyrosinase activity in a non-competitive fashion for both substrates, tyrosine and DOPA. These results suggest that 3 might be a useful alternative to kojic acid as a tyrosinase inhibitor.

Topics: Agaricales; Aminophenols; Enzyme Inhibitors; Kinetics; Monophenol Monooxygenase; Protein Binding; Pyrones; Structure-Activity Relationship; Tretinoin

Some retinoic acid metabolism blocking agents (RAMBAs) are known to exhibit a wide range of anticancer activities by mechanisms that are still not completely resolved. This study investigated the anticancer efficacy and mechanism(s) of novel RAMBA retinamides (RRs) in triple negative and Her-2 overexpressing breast cancer cells. Specifically, we examined the possibility that RRs affect the translational machinery in these breast cancer (BC) cells. Recent findings suggest that overexpression of eukaryotic translation initiation factor 4E (eIF4E) in breast cancers critically augments CAP-dependent mRNA translation and synthesis of proteins involved in cell growth, cell proliferation, invasion and apoptosis evasion. The oncogenic potential of eIF4E is strictly dependent on serine209 phosphorylation by upstream MAPK-interacting kinases (Mnks). Targeting Mnk/eIF4E pathway for blocking Mnk function and eIF4E phosphorylation is therefore a novel approach for treating BCs, particularly for Her2-positive and triple negative breast cancers that have no indications for endocrine therapy or effective treatment regimes. We report for the first time that the degradation of Mnk1 by RRs in BC cells blocks eIF4E phosphorylation and subsequently inhibits cell growth, colonization, invasion, and migration and induce apoptosis. Most importantly, the anticancer efficacy of RRs was mediated via degrading Mnk rather than inhibiting its kinase activity like Mnk inhibitors (cercosporamide and CGP57380). Furthermore, RRs potencies on peIF4E down-regulation and growth inhibition were superior to those of two clinically relevant retinoids and the Mnk inhibitors. Together our findings provide the first preclinical proof-of-concept of novel Mnk degrading agents for Mnk/eIF4E based therapeutic treatment of breast cancers.

Topics: Apoptosis; Cell Line, Tumor; Cell Movement; Cell Proliferation; Eukaryotic Initiation Factor-4E; Female; Humans; Intracellular Signaling Peptides and Proteins; Phosphorylation; Protein Serine-Threonine Kinases; Receptor, ErbB-2; Transfection; Tretinoin; Triple Negative Breast Neoplasms

Targeting tumor-specific metabolic adaptations is a promising anticancer strategy when tumor defense mechanisms are restrained. Here, we show that redox-modulating drugs including the retinoid N-(4-hydroxyphenyl)retinamide (4HPR), the synthetic triterpenoid bardoxolone (2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid methyl ester), arsenic trioxide (As2O3), and phenylethyl isothiocyanate (PEITC), while affecting tumor cell viability, induce sustained Ser9 phosphorylation of the multifunctional kinase glycogen synthase kinase 3β (GSK3β). The antioxidant N-acetylcysteine decreased GSK3β phosphorylation and poly(ADP-ribose) polymerase cleavage induced by 4HPR, As2O3, and PEITC, implicating oxidative stress in these effects. GSK3β phosphorylation was associated with up-regulation of antioxidant enzymes, in particular heme oxygenase-1 (HO-1), and transient elevation of intracellular glutathione (GSH) in cells surviving acute stress, before occurrence of irreversible damage and death. Genetic inactivation of GSK3β or transfection with the non-phosphorylatable GSK3β-S9A mutant inhibited HO-1 induction under redox stress, while tumor cells resistant to 4HPR exhibited increased GSK3β phosphorylation, HO-1 expression, and GSH levels. The above-listed findings are consistent with a role for sustained GSK3β phosphorylation in a signaling network activating antioxidant effector mechanisms during oxidoreductive stress. These data underlie the importance of combination regimens of antitumor redox drugs with inhibitors of survival signaling to improve control of tumor development and progression and overcome chemoresistance.

Topics: Antineoplastic Agents; Apoptosis; Cell Death; Cell Line; Cell Line, Tumor; Cell Survival; Drug Resistance, Neoplasm; Gene Silencing; Glucose; Glutathione; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Heme Oxygenase-1; Humans; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Neoplasms; Oxidation-Reduction; Oxidative Stress; Phosphorylation; Reactive Oxygen Species; Signal Transduction; Tretinoin

To observe the effects of a novel all-trans retinoid acid (ATRA) derivative, N-(3-trifluoromethyl-phenyl)- retinamide (ATPR), on lung adenocarcinoma A549 cells and to explore the potential mechanism of ATPR inhibiting of A549 cell migration.. The cytotoxicity of ATRA and ATPR on A549 cells was assessed using MTT assay. Wound healing assays were used to analyze the influences of ATRA, ATPR, ML-7 (a highly selective inhibitor of myosin light chain kinase (MLCK)), PMA (an activator of MAPKs) and PD98059 (a selective inhibitor of ERK1/2) on the migration of A549 cells. Expression of MLCK and phosphorylation of myosin light chain (MLC) were assessed by Western blotting.. ATRA and ATPR inhibited the proliferation of A549 cells in a dose- and time-dependent manner, and the effect of ATPR was much more remarkable compared with ATRA. Relative migration rate and migration distance of A549 cells both decreased significantly after treatment with ATPR or ML-7. The effect on cell migration of PD98059 combining ATPR treatment was more notable than that of ATPR alone. Moreover, compared with control groups, the expression levels of MLCK and phosphorylated MLC in A549 cells were both clearly reduced in ATRA and ATPR groups.. ATPR could suppress the migration and invasion of A549 cells, and the mechanism might be concerned with down- regulating the expression of MLCK in the ERK-MAPK signaling pathway, pointing to therapeutic prospects in lung cancer.

Topics: Adenocarcinoma; Antineoplastic Agents; Apoptosis; Blotting, Western; Cell Cycle; Cell Movement; Cell Proliferation; Gene Expression Regulation, Enzymologic; Humans; Lung Neoplasms; Myosin-Light-Chain Kinase; Phosphorylation; Signal Transduction; Tretinoin; Tumor Cells, Cultured

The aim of the present study was to synthesize a series of retinamide derivatives using all-trans retinoic acid (ATRA) as raw material and observe their effects on the differentiation and apoptosis of human lung adenocarcinoma A549 cells. Four new synthesized ATRA retinamide derivatives were structurally confirmed by spectral analysis, including (1)H-NMR, (13)C-NMR, and MS. The results showed that the new ATRA retinamide derivatives significantly decreased the carcinoembryonic antigen secretion of A549 cells, significantly decreased the proliferation of A549 cells in a dose- and time-dependent manner, and promoted the apoptosis of A549 cells compared with ATRA. The Western blot assay indicated that the expression of Bcl-2 was decreased more in A549 cells treated with N-(3-trifluoromethylphenyl) retinamide than that in A549 cells treated with ATRA. The results also showed that the effects of N-(3-trifluoromethyl-phenyl) retinamide on differentiation and apoptosis were the strongest among the newly synthesized ATRA retinamide derivatives. Our results suggested that the effects of novel ATRA retinamide derivatives on increasing the differentiation, decreasing the proliferation, and promoting the apoptosis of A549 cells were greater than those of ATRA. The apoptosis of A549 cells induced by N-(3-trifluoromethylphenyl) retinamide may be related to downregulating the expression of Bcl-2.

Topics: Adenocarcinoma; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Chromatin; DNA Fragmentation; DNA, Neoplasm; Dose-Response Relationship, Drug; Humans; Lung Neoplasms; Structure-Activity Relationship; Tretinoin

Neuroblastoma is the childhood malignancy that mainly occurs in adrenal glands and is found also in the neck, chest, abdomen, and pelvis. New therapeutic strategies are urgently needed for successful treatment of this pediatric cancer. In this investigation, we examined efficacy of the retinoid N-(4-hydroxyphenyl) retinamide (4-HPR) and the isoflavonoid genistein (GST) alone and also in combination for controlling the growth of human malignant neuroblastoma SK-N-BE2 and SH-SY5Y xenografts in nude mice. Combination of 4-HPR and GST significantly reduced tumor volume in vivo due to overwhelming apoptosis in both neuroblastoma xenografts. Time-dependently, combination of 4-HPR and GST caused reduction in body weight, tumor weight, and tumor volume. Combination of 4-HPR and GST increased Bax:Bcl-2 ratio, mitochondrial release of Smac, downregulation of baculovirus inhibitor-of-apoptosis repeat containing (BIRC) proteins including BIRC-2 and BIRC-3, and activation of caspase-3 and apoptosis inducing factor (AIF). Further, downregulation of nuclear factor-kappa B (NF-kappaB), vascular endothelial growth factor (VEGF), and fibroblast growth factor 2 (FGF2) was also detected. In situ immunofluorescent labelings of tumor sections showed overexpression of calpain, caspase-12, and caspase-3, and also AIF in the course of apoptosis. Combination therapy increased apoptosis in the xenografts but did not induce kidney and liver toxicities in the animals. Results demonstrated that combination of 4-HPR and GST induced multiple molecular mechanisms for apoptosis and thus could be highly effective for inhibiting growth of malignant neuroblastoma in preclinical animal models.

Topics: Animals; Anticarcinogenic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Apoptosis Regulatory Proteins; Body Weight; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Genistein; Humans; Intercellular Signaling Peptides and Proteins; Mice; Mice, Nude; Neuroblastoma; NF-kappa B; Transplantation, Heterologous; Treatment Outcome; Tretinoin; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

A highly sensitive, rapid and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitative determination of retinamido-ester in rat plasma was developed and validated. A simplified protein precipitation with acetonitrile was employed for the sample preparation. The separation was carried out on an Agilent TC C18 column (150 mm x 4.6 mm ID, 5 microm particle size) with the mobile phase consisted of methanol-water-formic acid (93: 7: 0.1). Simvastatin was used as internal standard. The detection was performed on a trap-quadrupole tandem mass spectrometer by selected reaction monitoring (SRM) scan mode via atmospheric pressure chemical ionization (APCI). The range of calibration curve was 0.05-50 ng x mL(-1) and the limit of quantification was 10 pg x mL(-1). The intra- and inter-day precision values were between 95.97% and 104.43%, and RSD was between 4.63% and 10.69%, respectively. This method was applied to determine the pharmacokinetic parameters. The main pharmacokinetic parameters of retinamido-ester after oral administration via gastric gavage of 2.5, 5, 10 mg x kg(-1) were as follows, T(1/2): (11.28 +/- 7.23), (8.90 +/- 3.82), (8.01 +/- 5.65) h; AUC(0-infinity): (103.41 +/- 61.46), (190.23 +/- 74.99), (421.66 +/- 229.20) ng x h x mL(-1); MRT: (6.31 +/- 0.75), (5.98 +/- 0.71), (6.18 +/- 0.97) h; CL/F: (30.10 +/- 13.67), (29.58 +/- 10.59), (31.18 +/- 17.51) L x h(-1) x kg(-1); Vd/F: (414.94 +/- 159.82), (356.16 +/- 139.85), (369.28 +/- 322.72) L x kg(-1), respectively.

Topics: Administration, Oral; Animals; Antineoplastic Agents; Area Under Curve; Chromatography, Liquid; Rats; Rats, Sprague-Dawley; Tandem Mass Spectrometry; Tretinoin

We previously reported that N-(4-hydroxyphenyl)retinamide (4HPR) inhibits retinoblastoma tumor growth in a murine model in vivo and kills Y79 retinoblastoma cells in vitro. In this work, we assayed different cell death-related parameters, including mitochondrial damage and caspase activation, in Y79 cells exposed to 4HPR. 4HPR induced cytochrome c release from mitochondria, caspase-3 activation, and oligonucleosomal DNA fragmentation. However, pharmacologic inactivation of caspases by the pan-caspase inhibitor BOC-D-fmk, or specific caspase-3 inhibition by Z-DEVD-fmk, was not sufficient to prevent cell death, as assessed by loss of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction, lactate dehydrogenase release, disruption of mitochondrial transmembrane potential (Deltapsi(m)), and ATP depletion. We found that 4HPR causes lysosomal membrane permeabilization and cytosolic relocation of cathepsin D. Pepstatin A partially rescued cell viability and reduced DNA fragmentation and cytosolic cytochrome c. The antioxidant N-acetylcysteine attenuated cathepsin D relocation into the cytosol, suggesting that lysosomal destabilization is dependent on elevation of reactive oxygen species and precedes mitochondrial dysfunction. Activation of AKT, which regulates energy level in the cell, by the retinal survival facto]r insulin-like growth factor I was impaired and insulin-like growth factor I was ineffective against ATP and Deltapsi(m) loss in the presence of 4HPR. Lysosomal destabilization, associated with mitochondrial dysfunction, was induced by 4HPR also in other cancer cell lines, including PC3 prostate adenocarcinoma and the vascular tumor Kaposi sarcoma KS-Imm cells. The novel finding of a lysosome-mediated cell death pathway activated by 4HPR could have implications at clinical level for the development of combination chemoprevention and therapy of cancer.

Topics: Acetylcysteine; Adenosine Triphosphate; Antineoplastic Agents; Benzyl Compounds; Caspase Inhibitors; Cathepsin D; Cell Death; Cell Survival; Cytochromes c; Cytosol; Enzyme Activation; Flow Cytometry; Humans; Hydrocarbons, Fluorinated; Insulin-Like Growth Factor I; Lysosomes; Membrane Potential, Mitochondrial; Mitochondria; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; Retinoblastoma; Time Factors; Tretinoin

Glioblastomas are among the most difficult neoplasms to treat with continued poor prognosis for long-term survival. Glioblastomas have developed effective mechanisms to resist chemotherapy including levels anti-apoptotic proteins, Bcl-xL and Bcl-2. Chemotherapy agents that promote down-regulation of Bcl-xL and Bcl-2 may enhance sensitivity to chemotherapy in glioblastomas. The ability of the synthetic retinoid N-(4-hydroxyphenyl) retinamide to modulate these anti-apoptotic proteins and to enhance apoptosis and chemotherapy was examined in glioblastoma cells. Expression of Bcl-2 family member proteins Bcl-xL and Bcl-2 were assessed in glioblastomas from three cell lines including U87, U251, and U138. Cells were treated with either retinamide alone or in combination with the chemotherapy agent, BCNU. The incidence of apoptosis was determined with flow cytometry analysis (FACS). Based on Western blots the levels of Bcl-2 and Bcl-xL were decreased in glioblastoma cells after treatment with retinamide. Retinamide treatment resulted in increased ratios of deamidated verses transamidated levels of Bcl-xL in U87 cells. BCNU chemotherapy combined with retinamide markedly down-regulated levels of both Bcl-xL and Bcl-2 proteins in glioblastoma and enhanced the incidence of apoptosis in U87 cells. These studies demonstrate that modulation of levels of the anti-apoptotic proteins, Bcl-xL and Bcl-2, may enhance the sensitivity of glioblastoma toward chemotherapy.

Topics: Antineoplastic Agents; Antineoplastic Agents, Alkylating; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Blotting, Western; Brain Neoplasms; Carmustine; Caspases; Down-Regulation; Flow Cytometry; Glioblastoma; Humans; Proto-Oncogene Proteins c-bcl-2; Tretinoin; Tumor Cells, Cultured

Retinoic acid and its amide derivative, N-(4-hydroxyphenyl)retinamide (4-HPR), have been proposed as chemopreventative and chemotherapeutic agents. However, their low cytotoxic activity and water solubility limit their clinical use. In this study, we synthesized novel retinoid derivatives with improved cytotoxicity against cancer cells and increased hygroscopicity. Our syntheses were preceded by selective O-acylation and N-acylation, which led to the production of retinoate and retinamide derivatives, respectively, in one pot directly from aminophenol derivatives and retinoic acid without protection. Transcription assays in COS-1 cells indicated that the N-acylated derivatives (2A-5A) and 4-HPR (1A) were much weaker ligands for all three subtypes of retinoic acid receptor (RAR) than all-trans retinoic acid (ATRA), although they showed some selectivity for RARbeta and RARgamma. In contrast, the O-acylated retinoate derivatives (1B-5B) activated all three RAR isotypes without specificity to an extent similar to ATRA. The cytotoxicity was determined using an MTT assay with HCT116 colon cancer cells, and the IC(50) of N-acylated retinamide derivative 4A and O-acylated retinoate derivative 5B was 1.67 microM and 0.65 microM, respectively, which are about five and 13-fold better than that of 4-HPR (8.21 microM), a prototype N-acylated derivative. When retinoate derivative 5B was coupled to organic acid salts, the resulting salt derivatives 5C and 5D had RAR activation and cytotoxicity similar to those of 5B. These data may delineate the relationship between the structure and function of retinoate and retinamide derivatives.

Topics: Animals; Chlorocebus aethiops; COS Cells; Fenretinide; HCT116 Cells; Humans; Receptors, Retinoic Acid; Tretinoin

The synthetic retinoid N-(4-hydroxphenyl) retinamide (4HPR) has manifold actions, which may contribute to its chemopreventive effects on breast cancer cell growth and progression. A role for ceramide as a stress-response signal is investigated here during the cytotoxic action of 4HPR in MCF-7 cells. N-(4-hydroxphenyl) retinamide induced a dose-dependent decline in cell growth and survival associated with a maximal 10-fold increase in ceramide production at 10 microM. N-(4-hydroxphenyl) retinamide exhibited a greater potency than all-trans retinoic acid (ATRA) on growth inhibition and ceramide production. The synthetic peroxisome proliferator-activated receptors agonist troglitazone (TGZ), but not the native ligand 15-deoxy-delta 12,14-prostaglandin J2, abrogated both these actions of 4HPR but not that of ATRA. The antioxidant N-acetylcysteine mimicked the abrogative effect of TGZ on 4HPR action, while the exogenous oxidant H2O2 also stimulated ceramide production. The inhibitors of de novo ceramide synthesis, fumonisin B1 and myriocin, blocked the ceramide response to 4HPR and partially reversed the apoptotic response, but did not prevent the overall decline in cell survival. The pancaspase inhibitor Z-VAD fmk reduced the decrease in cell survival caused by 4HPR, but did not affect the ceramide response. These findings describe a novel redox-sensitive elevation of ceramide levels associated with the cytotoxic response of breast cancer cells to 4HPR. However, a major mediatory role for this sphingolipid in this context remains equivocal.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Division; Cell Survival; Ceramides; Fenretinide; Glucosylceramides; Humans; Oxidation-Reduction; PPAR gamma; Tretinoin; Tumor Cells, Cultured

The synthetic retinoid N-(4-hydroxyphenyl)retinamide [4-HPR (or fenretinide)] has preclinical and clinical preventive activity in breast carcinogenesis. 4-HPR and its metabolites have been shown to accumulate in the mammary tissue of rodents. We assessed levels of 4-HPR and its major metabolite, N-(4-methoxyphenyl)retinamide (4-MPR), in plasma and in normal and neoplastic breast tissue obtained from women treated with 4-HPR.. We randomly assigned 14 women with suspected or very recently diagnosed breast cancer to receive 100, 200, or 300 mg of 4-HPR daily for 3-12 days before scheduled biopsy, lumpectomy, or mastectomy. Using high-performance liquid chromatography, we measured post-4-HPR-treatment concentrations of 4-HPR and 4-MPR in plasma and breast tissue obtained during surgery.. Breast tissue and plasma retinamide (4-HPR plus 4-MPR) concentrations increased significantly with short-term oral administration of 4-HPR. Retinamide levels increased in a linear and dose-related fashion in plasma, whereas they peaked and plateaued at 200 mg/day in breast tissue. The total retinamide concentration in breast tissue exceeded that in plasma at each 4-HPR dose. The highest mean tissue:plasma retinamide ratios were achieved at 200 mg/day: 639.5 +/- 253.8 to 190.6 +/- 91.9 ng/ml (4.8:1) for 4-HPR and 594.4 +/- 201.9 to 130.5 +/- 37.8 ng/ml (6.6:1) for 4-MPR. Plasma retinol levels decreased in association with increasing 4-HPR doses. Two patients experienced grade 1 toxicity at the 300 mg/day dose.. These findings indicate that retinamides preferentially accumulate in human breast tissue (versus plasma). 4-HPR tissue concentrations at 200 mg/d were equivalent to those that inhibit growth and induce apoptosis of breast cancer cells in vitro. Previous clinical and correlative laboratory results suggest that 4-HPR may reduce risk in premenopausal women, who are more prone (than are postmenopausal women) to estrogen receptor (ER)-negative breast cancer development. The present results and previous data (including in vitro 4-HPR activity against ER-negative breast cancer) support further study of 4-HPR in the setting of premenopausal/ER-negative breast cancer prevention.

Topics: Administration, Oral; Adult; Aged; Apoptosis; Breast; Breast Neoplasms; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Female; Fenretinide; Humans; Kinetics; Middle Aged; Random Allocation; Time Factors; Tretinoin

4-(N-Hydroxyphenyl)retinamide (also known as 4-HPR or fenretinide), a synthetic amide of all-trans retinoic acid (RA), has been implicated as a promising anticancer agent associated with reducing the toxicity related to RA. However, the low plasma levels of 4-HPR in patients limited clinical trials, leading to a search for derivatives with better efficacy. In this study, we synthesized a series of 4-HPR derivatives in good yields by introducing acetate (compound 1). propionate (2). pyruvate (3). butyrate (4). or stearate (5). to the 4-hydroxylphenyl moiety of 4-HPR. In our initial proliferation assays, we identified compound 3 as the most cytotoxic of the series against four ovarian cancer cell lines (OVCAR-3, PA-1, 2774, and SKOV-3). Dose-response curves yielded IC(50) values of 3.75-7.75 microM for AtRA, 2.80-5.50 microM for 9-cis RA, 0.65-4.05 microM for 4-HPR, and 0.25-0.75 microM for compound 3, depending on the cell type treated. Nuclear staining with 4',6-diamidino-2-phenylindole (DAPI) and DNA fragmentation assays clearly indicated that the antiproliferative effect of compound 3 was mediated by apoptosis. In contrast to natural retinoids, both 4-HPR and compound 3 activated two (RARbeta and RARgamma) of the three retinoic acid receptor (RAR) subtypes tested, but did not activate any of the three retinoid X receptors (RXRs), as determined by transcription assays in OVCAR-3 cells. However, like natural retinoids, 4-HPR and compound 3 actively suppressed c-Jun transcriptional activity. Thus, compound 3 not only showed more potent antiproliferative activity than any other retinoid derivatives tested, but also effectively inhibited the c-Jun activity that has been implicated in tumor promotion and invasion. These results, together with compound 3's selectivity for RAR subtypes, suggest that compound 3 could be an effective anticancer drug for ovarian cancer, with less toxicity than RA.

Topics: Cell Count; Cell Division; Cell Line, Tumor; Dose-Response Relationship, Drug; Female; Humans; Ovarian Neoplasms; Tretinoin

The retinamide, N-(4-hydroxyphenyl)retinamide (4-HPR), has shown promising anti-tumor activity, but it is unclear whether this compound is hydrolyzed to all-trans retinoic acid (atRA) and if so, whether this plays any role in its chemotherapeutic activity. To address this issue, the ability of 4-hydroxybenzylretinone (4-HBR), a carbon-linked analog of 4-HPR, to support growth in vitamin A-deficient (VAD) animals and to activate an atRA-responsive gene in vivo was compared to 4-HPR and atRA. Further, the non-hydrolyzable 4-HBR analog was used to determine whether the presence of the labile amide linkage in 4-HPR is essential for the induction of apoptosis in cultured MCF-7 breast cancer cells. Studies in VAD rats showed that 4-HPR, like atRA, supports animal growth and induces CYP26B1 mRNA expression in lung whereas 4-HBR does not. Analysis of plasma from 4-HPR- and atRA-treated VAD animals revealed the presence of atRA whereas it was not detected in plasma from animals given 4-HBR. To determine whether hydrolysis to atRA is necessary for apoptosis induced by 4-HPR in MCF-7 breast cancer cells, morphological and biochemical assays for apoptosis were performed. 4-HBR, like 4-HPR, induced apoptosis in MCF-7 cells. Apoptosis was not induced even at high concentrations of atRA, showing that 4-HPR and 4-HBR act in cells via a distinct signaling pathway. These results show that although limited hydrolysis of 4-HPR occurs in vivo, the ability to liberate atRA is not required for these 4-hydroxyphenyl retinoids to induce apoptosis in MCF-7 breast cancer cells. Thus the non-hydrolyzable analog, 4-HBR, may have significant therapeutic advantage over 4-HPR because it does not liberate atRA that can contribute to the adverse side effects of drug administration in vivo.

Topics: Administration, Oral; Animals; Apoptosis; Body Weight; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Dose-Response Relationship, Drug; Fenretinide; Humans; Hydrolysis; Male; Rats; Rats, Sprague-Dawley; Tretinoin; Vitamin A; Vitamin A Deficiency

Superficial bladder cancer is a major target for chemoprevention. Retinoids are important modulators of epithelial differentiation and proliferation and are effective in the treatment and prevention of several epithelial cancers. One class of compounds, the retinamides, is structurally similar to other retinoids but have the added feature of being potent apoptosis inducers. Among these, fenretinide (N-[4-hydroxyphenyl]retinamide), or 4HPR, has promise for bladder cancer chemoprevention and is currently under Phase III study in this setting. In addition to 4HPR, there are several new structurally related phenylretinamides bearing hydroxyl, carboxyl, or methoxyl residues on carbons 2, 3, and 4 of the terminal phenylamine ring [designated N-(2-hydroxyphenyl)retinamide, N-(3-hydroxyphenyl)retin amide, N-(2-carboxyphenyl)retin- amide, N-(3-carboxyphenyl)retin amide, N-(4-carboxy- phenyl)retinamide, and N-(4-methoxyphenyl)retinamide, respectively]. The objective of this study was to compare the growth inhibitory and apoptotic effects of these phenylretinamides with 4HPR in human bladder transitional cell cancer-derived cell lines of varying histological grade (RT4, grade 1; UM-UC9 and UM-UC10, grade 3; and UM-UC14, grade 4) by cell counting, cell cycle fluorescence-activated cell sorter analysis and a dual stain apoptosis assay. All of the seven phenylretinamides reduced cell number, altered the cell cycle distribution, and induced apoptosis when administered at a concentration of 10 microM, which is within the pharmacologically achievable range. Although the relative potencies of the phenylretinamides varied depending on the cell line, N-(3-hydroxy phenyl)retin- amide was the most active with significantly greater growth inhibition than 4HPR in all of the four cell lines. These in vitro findings warrant further study of these novel phenylretinamides, which may have potential as preventive or therapeutic agents in transitional cell cancer.

Topics: Anticarcinogenic Agents; Antineoplastic Agents; Apoptosis; Carcinoma, Transitional Cell; Cell Division; Fenretinide; Humans; Retinoids; Tretinoin; Tumor Cells, Cultured; Urinary Bladder Neoplasms

The synthetic retinoid, N-(4-hydroxyphenyl)retinamide (4HPR), which is currently being evaluated in clinical trials for cancer prevention and therapy, inhibits the growth of a variety of malignant cells through induction of apoptosis. However, in the majority of tumor cells, this inhibitory effect of 4HPR requires high concentrations (>1 microM), which exceed the peak plasma level measured in humans. In the present study, we compared and contrasted the effects of several synthetic retinamides on the growth of human lung and head and neck cancer cells in vitro. We found that some retinamides, especially N-(2-carboxyphenyl)retinamide (2CPR), exhibited better growth inhibitory effects than 4HPR in some of the cell lines. 2CPR exerted potent growth inhibitory effects in 5 of 10 head and neck cancer cell lines and in 1 of 10 lung cancer cell lines (IC(50), <0.8 microM). 2CPR (1 microM) induced apoptosis ranging from 10 to 60% in four of five cell lines, whereas 4HPR was ineffective at the same concentration. Unlike 4HPR, 2CPR (up to 10 microM) failed to induce reactive oxygen species production in these sensitive cell lines but could activate caspases 3 and 7 as well as increase poly(ADP-ribose)polymerase cleavage. Interestingly, the effect of 2CPR on cell growth could be suppressed by the specific retinoic acid receptor pan antagonist AGN193109. Our results suggest that 2CPR acts via retinoic acid receptors and may be a good candidate for prevention and treatment of some head and neck and lung cancers.

Topics: Anticarcinogenic Agents; Apoptosis; Carcinoma, Non-Small-Cell Lung; Fenretinide; Head and Neck Neoplasms; Humans; Lung Neoplasms; Reactive Oxygen Species; Receptors, Retinoic Acid; Retinoids; Tretinoin; Tumor Cells, Cultured

The interaction between the retinol binding protein and four ligands was evaluated using HINT, a software based on experimental LogP values of individual atoms. A satisfactory correlation was found between the HINT scores and the experimental dissociation constants of three of the ligands, fenretinide, N-ethylretinamide and all-trans retinol, despite their hydrophobic nature. A prediction is made for the binding affinity of the fourth ligand, axerophtene, not yet determined in solution.

Topics: Algorithms; Antineoplastic Agents; Diterpenes; Fenretinide; Humans; Ligands; Models, Molecular; Protein Binding; Retinol-Binding Proteins; Solubility; Tretinoin; Vitamin A

The retinamide-mediated apoptosis of promyelocytic cells was investigated using pHi- and DNA-sensitive fluorescent probes (BCECF and Hoechst 33342). Acidification and apoptosis were observed during prolonged (0-12 h) exposure to retinamide (1 microM), but were absent in a retinamide-resistant clone. The analysis of experiments performed by simultaneous staining with the two dyes showed that acidification and apoptosis are correlated; the half-time for acidification is about 5 h while that for apoptosis is 80% longer. On the whole, these results suggest that apoptosis is preceded by an early mechanism of acidification in human leukemia cells treated by a retinoid of clinical interest in cancer chemo prevention and therapy.

Topics: Apoptosis; Benzimidazoles; Cell Cycle; Cytoplasm; Fluoresceins; Humans; Hydrogen-Ion Concentration; Leukemia, Promyelocytic, Acute; Tretinoin; Tumor Cells, Cultured

Vitamin A and its analogus, the retinoids, are agents that are known to induce differentiation and inhibit growth on cell in vitro and in vivo. These agents show promise as prophylactic and therapeutic ones in human cancer and were noted extensively by scholars abroad, but the research has just been developed in recent years in our country. Retinamide (named briefly R II), a kind of new retinoids made in China, can induce differentiation and inhibit growth of cell, but its toxic effect is smaller than its maternal chemical compound (retinoic acid). Using automatic image analysis technology, polyacrylamide gel LDH isoenzyme electrophoresis, radioimmunoassay and condensing reaction of Con A, we have observed induction of differentiation of the R II on SGC-7901 cells. Our experiments indicate that R II can inhibit cell proliferation, decrease obviously average DNA content and nuclear area, reduce CEA secretion and condensing of the cells, and change LDH isozymoraphy of SGC-7901 cell with promoting H-type LDH and reducing M-type LDH. The change of morphology under light microscope by R II showed that the cells spread, flattened and partially lined up, and the alkalophilic quality of cytoplasm became weak. These results suggest that SGC-7901 cell under the action of R II should undergo the changes of reverse differentiation in morphological, physiological and bio-chemical aspects.

Topics: Antineoplastic Agents; Carcinoembryonic Antigen; Cell Transformation, Neoplastic; DNA, Neoplasm; Humans; L-Lactate Dehydrogenase; Stomach Neoplasms; Tretinoin; Tumor Cells, Cultured

The model of precancerous lesions of the bladder in rats was induced by N-butyl-(4-hydroxybutyl) nitrosamide (BBN). The animals were randomly divided into the following 3 groups: 1) given Antitumor-B (Chinese herbs); 2) given 4-ethoxycarbophenylretinamide (Retinamide); and 3) control. After treatment for 13 months the rats were killed for pathomorphological examination of the bladder. The results showed that the incidence of bladder cancer in group 1 and 2 was reduced by 90.7% (P < 0.01) and 75.0% (P < 0.01) respectively after treatment as compared with the control group. Our results provide a useful reference for clinical trial in the prevention of bladder cancer recurrence by using antitumor-B and Retinamide.

Topics: Animals; Antineoplastic Agents, Phytogenic; Butylhydroxybutylnitrosamine; Carcinoma, Transitional Cell; Drugs, Chinese Herbal; Precancerous Conditions; Rats; Rats, Wistar; Tretinoin; Urinary Bladder Neoplasms

Topics: Animals; Female; Lymphoma; Mice; Mice, Inbred DBA; T-Lymphocytes, Cytotoxic; Tretinoin; Tumor Cells, Cultured

Retinoyl beta-glucuronide and retinyl beta-glucuronide, which are naturally occurring water-soluble metabolites of vitamin A, induce the granulocytic differentiation of HL-60 cells in vitro, as evidenced by an increased reduction of nitroblue tetrazolium. The relative effectiveness of various retinoids in differentiation is retinoic acid greater than retinoyl beta-glucuronide greater than retinyl beta-glucuronide. Under the selected assay conditions, retinol, hydroxyphenyl-retinamide, retinamide, and N-retinoyl-phenylalanine are essentially inactive in differentiation. At concentrations of retinoids from 10(-9) to 10(-5) M, cell viability was best with the retinoid beta-glucuronides and retinamide, less with retinoic acid and retinol, and poorest with the N-retinoyl aromatic amines. Cellular growth was depressed only slightly by retinyl beta-glucuronide and retinamide, but to a greater degree by the other derivatives. Retinoyl beta-glucuronide was hydrolyzed in part to retinoic acid, whereas retinyl beta-glucuronide was cleaved to retinol, if at all, at a very slow rate. Under the selected assay conditions, retinoic acid and the retinoid beta-glucuronides primarily induce the differentiation of HL-60 cells, whereas the N-retinoyl aromatic amines show cytotoxicity.

Topics: Cell Differentiation; Cell Division; Cell Line; Fenretinide; Humans; Leukemia, Myeloid, Acute; Nitroblue Tetrazolium; Oxidation-Reduction; Tretinoin; Vitamin A

Twenty seven women with mild, moderate or severe cervical dysplasia proven by pathology were treated by retinamide RII suppository. Retinamide RII suppository, 10 mg QD, was given intravaginally for six months (three months as a course). Clinical examination, Papanicolaou cytology and tissue biopsy under colposcope were carried out before and after treatment. The results indicated that after the second course, 26 out of 27 patients responded; of them, precancerous lesions disappeared in 24 and even normal squamous epithelium was observed in 3. The overall response rate was 96.29% and the marked response rate was 88.89%. The general side effects were mild. There was little cervical and vaginal irritation which was well tolerated. The results of this clinical trial make available a practical base for chemoprevention of cervical cancer.

Topics: Antineoplastic Agents; Cervix Uteri; Female; Humans; Hyperplasia; Precancerous Conditions; Suppositories; Tretinoin; Uterine Cervical Neoplasms