phenanthrenes and Cell-Transformation--Neoplastic

In mammals, the cytoprotective heat-shock response is regulated primarily by heat shock factor 1 (HSF1). Unfortunately, the effects of HSF1 also support the ability of cancer cells to accommodate imbalances in signaling and alterations in DNA, protein and energy metabolism associated with oncogenesis. The malignant lifestyle confers dependence on this 'non-oncogene', suggesting a therapeutic role for HSF1 inhibitors.. We begin with an overview of how HSF1 affects cancer biology and how its activity is regulated. We then summarize progress in discovery and development of HSF1 inhibitors, their current limitations and potential as anticancer agents with a fundamentally different scope of action from other clinically validated modulators of protein homeostasis.. It is likely that within the next 5 years usable inhibitors of HSF1 will be identified and in early pre-clinical evaluation.

Topics: Animals; Antineoplastic Agents; Cell Survival; Cell Transformation, Neoplastic; Diterpenes; DNA-Binding Proteins; Drug Delivery Systems; Drug Design; Epoxy Compounds; Female; Gene Expression Regulation, Neoplastic; Heat Shock Transcription Factors; Heat-Shock Proteins; Humans; Male; Mice; Mice, Knockout; Molecular Chaperones; Neoplasm Proteins; Phenanthrenes; Quercetin; Stress, Physiological; Transcription Factors; Transcription, Genetic

Topics: Animals; Antineoplastic Agents; Arginase; Benz(a)Anthracenes; Benzopyrenes; Carcinogens; Cell Division; Cell Transformation, Neoplastic; Deoxyribonucleases; DNA; Fluorouracil; Humans; Liver Neoplasms; Methylcholanthrene; Mice; Mutation; Neoplasms; Neoplasms, Experimental; Nucleosides; Oncogenic Viruses; Orotic Acid; Phenanthrenes; Protein Binding; Pyrimidinones; Rats; Skin Neoplasms; Thymine; Uracil

Topics: Carcinogenesis; Cell Line, Tumor; Cell Transformation, Neoplastic; Colorectal Neoplasms; Glutamine; Humans; Lipids; Lipogenesis; Pancreatic Neoplasms; Phenanthrenes; Proto-Oncogene Proteins p21(ras); Reactive Oxygen Species; Signal Transduction

Disruption of the enzymatic activities of the transcription factor TFIIH by the small molecules Triptolide (TPL) or THZ1 could be used against cancer. Here, we used the MCF10A-ErSrc oncogenesis model to compare the effect of TFIIH inhibitors between transformed cells and their progenitors. We report that tumour cells exhibited highly increased sensitivity to TPL or THZ1 and that the combination of both had a synergic effect. TPL affects the interaction between XPB and p52, causing a reduction in the levels of XPB, p52 and p8, but not other TFIIH subunits. RNA-Seq and RNAPII-ChIP-Seq experiments showed that although the levels of many transcripts were reduced, the levels of a significant number were increased after TPL treatment, with maintained or increased RNAPII promoter occupancy. A significant number of these genes encode for factors that have been related to tumour growth and metastasis, suggesting that transformed cells might rapidly develop resistance to TPL/THZ inhibitors. Some of these genes were also overexpressed in response to THZ1, of which depletion enhances the toxicity of TPL, and are possible new targets against cancer.

Topics: Breast Neoplasms; Cell Line, Tumor; Cell Transformation, Neoplastic; Diterpenes; DNA Helicases; DNA-Binding Proteins; Epoxy Compounds; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; MCF-7 Cells; Models, Biological; Molecular Dynamics Simulation; Phenanthrenes; Phenylenediamines; Pyrimidines; Sequence Analysis, RNA; Transcription Factor TFIIH

Somatic mutations of calreticulin (CALR) have been described in approximately 60-80% of JAK2 and MPL unmutated Essential Thrombocythemia and Primary Myelofibrosis patients. CALR is an endoplasmic reticulum (ER) chaperone responsible for proper protein folding and calcium retention. Recent data demonstrated that the TPO receptor (MPL) is essential for the development of CALR mutant-driven Myeloproliferative Neoplasms (MPNs). However, the precise mechanism of action of CALR mutants haven't been fully unraveled. In this study, we showed that CALR mutants impair the ability to respond to the ER stress and reduce the activation of the pro-apoptotic pathway of the unfolded protein response (UPR). Moreover, our data demonstrated that CALR mutations induce increased sensitivity to oxidative stress, leading to increase oxidative DNA damage. We finally demonstrated that the downmodulation of OXR1 in CALR-mutated cells could be one of the molecular mechanisms responsible for the increased sensitivity to oxidative stress mediated by mutant CALR. Altogether, our data identify novel mechanisms collaborating with MPL activation in CALR-mediated cellular transformation. CALR mutants negatively impact on the capability of cells to respond to oxidative stress leading to genomic instability and on the ability to react to ER stress, causing resistance to UPR-induced apoptosis.

Topics: Calreticulin; Cell Transformation, Neoplastic; DNA Repair; Down-Regulation; Endoplasmic Reticulum Stress; Gene Knockdown Techniques; Humans; INDEL Mutation; K562 Cells; Mitochondrial Proteins; Mutant Proteins; Oxidative Stress; Phenanthrenes; Primary Myelofibrosis; Recombinant Proteins; Superoxide Dismutase; Thrombocythemia, Essential; Transcriptome; Unfolded Protein Response

Among primary brain cancers, gliomas are the most deadly and most refractory to current treatment modalities. Previous reports overwhelmingly support the role of the RNA-binding protein Hu antigen R (HuR) as a positive regulator of glioma disease progression. HuR expression is consistently elevated in tumor tissues, and a cytoplasmic localization appears essential for HuR-dependent oncogenic transformation. Here, we report HuR aggregation (multimerization) in glioma and the analysis of this tumor-specific HuR protein multimerization in clinical brain tumor samples. Using a split luciferase assay, a bioluminescence resonance energy transfer technique, and site-directed mutagenesis, we examined the domains involved in HuR multimerization. Results obtained with the combination of the split HuR luciferase assay with the bioluminescence resonance energy transfer technique suggested that multiple (at least three) HuR molecules come together during HuR multimerization in glioma cells. Using these data, we developed a model of HuR multimerization in glioma cells. We also demonstrate that exposing glioma cells to the HuR inhibitor tanshinone group compound 15,16-dihydrotanshinone-I or to the newly identified compound 5 disrupts HuR multimerization modules and reduces tumor cell survival and proliferation. In summary, our findings provide new insights into HuR multimerization in glioma and highlight possible pharmacological approaches for targeting HuR domains involved in cancer cell-specific multimerization.

Topics: Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cell Transformation, Neoplastic; ELAV-Like Protein 1; Furans; Glioma; Humans; Neoplasm Proteins; Phenanthrenes; Protein Aggregation, Pathological; Protein Domains; Quinones

Pancreatic adenocarcinoma is the fourth leading cause for cancer-related mortality with a survival rate of less than 5%. Late diagnosis and lack of effective chemotherapeutic regimen contribute to these grim survival statistics. Relapse of any tumor is largely attributed to the presence of tumor-initiating cells (TIC) or cancer stem cells (CSC). These cells are considered as hurdles to cancer therapy as no known chemotherapeutic compound is reported to target them. Thus, there is an urgent need to develop a TIC-targeted therapy for pancreatic cancer.. We isolated CD133(+) cells from a spontaneous pancreatic ductal adenocarcinoma mouse model and studied both surface expression, molecular markers of pancreatic TICs. We also studied tumor initiation properties by implanting low numbers of CD133(+) cells in immune competent mice. Effect of Minnelide, a drug currently under phase I clinical trial, was studied on the tumors derived from the CD133(+) cells.. Our study showed for the first time that CD133(+) population demonstrated all the molecular markers for pancreatic TIC. These cells initiated tumors in immunocompetent mouse models and showed increased expression of prosurvival and proinvasive proteins compared to the CD133(-) non-TIC population. Our study further showed that Minnelide was very efficient in downregulating both CD133(-) and CD133(+) population in the tumors, resulting in a 60% decrease in tumor volume compared with the untreated ones.. As Minnelide is currently under phase I clinical trial, its evaluation in reducing tumor burden by decreasing TIC as well as non-TIC population suggests its potential as an effective therapy.

Topics: AC133 Antigen; Animals; Antigens, CD; Antigens, Surface; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Cell Transformation, Neoplastic; Disease Models, Animal; Diterpenes; Epoxy Compounds; Gene Expression; Glycoproteins; Immunophenotyping; Mice; Mice, Transgenic; Neoplastic Stem Cells; NF-kappa B; Organophosphates; Pancreatic Neoplasms; Peptides; Phenanthrenes; Phenotype

Cryptotanshinone is one of the compounds extracted from the root of Salvia miltiorrhiza Bunge. Unlike other tanshinones, only a small number of studies have focused on cryptotanshinone for medical treatment. In the present study, the A549 lung cancer cell line and xenograft models of human lung tumors were used to assess the anti-cancer effect of cryptotanshinone. The effect of cryptotanshinone on human lung cancer, including growth inhibition, cell cycle arrest and apoptosis factors, were identified in vitro, and inhibition of tumor formation, improvement of body condition as well as pathological apoptotic effects were detected in vivo. These results suggested that cryptotanshinone is a potential drug for the treatment and prevention of human lung cancer.

Topics: Animals; Apoptosis; Body Weight; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Transformation, Neoplastic; Disease Models, Animal; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Humans; Lung Neoplasms; Mice; Phenanthrenes; Tumor Burden; Tumor Stem Cell Assay; Xenograft Model Antitumor Assays

Glioblastoma multiforme (GBM) is a lethal solid cancer in adults. Temozolomide (TMZ) is a first-line chemotherapeutic agent but the efficacy is limited by intrinsic and acquired resistance in GBM. Triptolide (TPL), a derivative from traditional Chinese medicine, demonstrated anti-tumor activity. In this study, we explored the interaction of TPL and TMZ in glioma-initiating cells (GICs) and the potential mechanism. A GIC line (GIC-1) was successfully established. Cell viability of GIC-1 after treatment was measured using a CCK-8 assay. The interaction between TPL and TMZ was calculated from Chou-Talalay equations and isobologram. Self-renewal was evaluated with tumor sphere formation assay. Apoptosis was assessed with flow cytometry and western blot. Luciferase assay was employed to measure NF-κB transcriptional activity. The expression of NF-κB downstream genes, NF-κB nuclear translocalization and phoshorylation of IκBα and p65 were evaluated using western blot. We found that GIC-1 cells were resistant to TMZ, with the expected IC50 of 705.7 μmol/L. Co-treatment with TPL yielded a more than three-fold dose reduction of TMZ. TPL significantly increased the percentage of apoptotic cells and suppressed the tumor sphere formation when combined with TMZ. Phosphorylation of IκBα and p65 coupled with NF-κB nuclear translocalization were notably inhibited after a combined treatment. Co-incubation synergistically repressed NF-κB transcriptional activity and downstream gene expression. TPL sensitizes GICs to TMZ by synergistically enhancing apoptosis, which is likely resulting from the augmented repression of NF-κB signaling. TPL is therefore a potential chemosensitizer in the treatment of GBM.

Topics: Animals; Antineoplastic Agents, Alkylating; Apoptosis; Cell Line, Tumor; Cell Transformation, Neoplastic; Dacarbazine; Disease Models, Animal; Diterpenes; Drug Synergism; Epoxy Compounds; Glioma; Humans; Mice; Neoplasm Transplantation; NF-kappa B; Phenanthrenes; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Stimulation, Chemical; Temozolomide; Transcription, Genetic; X-Linked Inhibitor of Apoptosis Protein

p38γ MAPK, one of the four members of p38 mitogen-activated protein kinases (MAPKs), has previously been shown to harbor oncogenic functions. However, the biologic function of p38γ MAPK in breast cancer has not been well defined. In this study, we have shown that p38γ MAPK is overexpressed in highly metastatic human and mouse breast cancer cell lines and p38γ MAPK expression is preferentially associated with basal-like and metastatic phenotypes of breast tumor samples. Ectopic expression of p38γ MAPK did not lead to an increase in oncogenic properties in vitro in most tested mammary epithelial cells. However, knockdown of p38γ MAPK expression resulted in a dramatic decrease in cell proliferation, colony formation, cell migration, invasion in vitro and significant retardation of tumorigenesis, and long-distance metastasis to the lungs in vivo. Moreover, knockdown of p38γ MAPK triggered the activation of AKT signaling. Inhibition of this feedback loop with various PI3K/AKT signaling inhibitors facilitated the effect of targeting p38γ MAPK. We further found that overexpression of p38γ MAPK did not promote cell resistance to chemotherapeutic agents doxorubicin and paclitaxel but significantly increased cell resistance to PJ-34, a DNA damage agent poly (ADP-ribose)-polymerase-1 (PARP) inhibitor in vitro and in vivo. Finally, we identified that p38γ MAPK overexpression led to marked cell cycle arrest in G(2)/M phase. Our study for the first time clearly demonstrates that p38γ MAPK is a promising target for the design of targeted therapies for basal-like breast cancer with metastatic characteristics and for overcoming potential resistance against the PARP inhibitor.

Topics: Animals; Breast Neoplasms; Cell Cycle; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Transformation, Neoplastic; Doxorubicin; Humans; Mice; Mitogen-Activated Protein Kinase 12; Neoplasm Invasiveness; Neoplasm Metastasis; Paclitaxel; Phenanthrenes; Phosphatidylinositol 3-Kinase; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-akt; Signal Transduction

Triptolide, a diterpenoid triepoxide from the traditional Chinese medicinal herb Tripterygium wilfordii Hook. f., is a potential treatment for autoimmune diseases as well a possible anti-tumor agent. It inhibits proliferation of colorectal cancer cells in vitro and in vivo. In this study, its ability to block progress of colitis to colon cancer, and its molecular mechanism of action are investigated. A mouse model for colitis-induced colorectal cancer was used to test the effect of triptolide on cancer progression. Treatment of mice with triptolide decreased the incidence of colon cancer formation, and increased survival rate. Moreover, triptolide decreased the incidence of tumors in nude mice inoculated with cultured colon cancer cells dose-dependently. In vitro, triptolide inhibited the proliferation, migration and colony formation of colon cancer cells. Secretion of IL6 and levels of JAK1, IL6R and phosphorylated STAT3 were all reduced by triptolide treatment. Triptolide prohibited Rac1 activity and blocked cyclin D1 and CDK4 expression, leading to G1 arrest. Triptolide interrupted the IL6R-JAK/STAT pathway that is crucial for cell proliferation, survival, and inflammation. This suggests that triptolide might be a candidate for prevention of colitis induced colon cancer because it reduces inflammation and prevents tumor formation and development.

Topics: Animals; Cell Transformation, Neoplastic; Colitis; Colonic Neoplasms; Dextran Sulfate; Dimethylhydrazines; Diterpenes; Epoxy Compounds; Humans; Interleukin-6; Janus Kinases; Male; Mice; Mice, Inbred BALB C; Mice, Inbred ICR; Mice, Nude; Neoplasm Transplantation; Phenanthrenes; rac1 GTP-Binding Protein; Signal Transduction; STAT3 Transcription Factor; Tumor Burden

A novel acetylenic tricyclic bis-(cyano enone), TBE-31, is a lead compound in a series of tricyclic compounds with enone functionalities in rings A and C. Nanomolar concentrations of this potent multifunctional molecule suppress the induction of the inflammatory protein, inducible nitric oxide synthase, activate phase 2 cytoprotective enzymes in vitro and in vivo, block cell proliferation, and induce differentiation and apoptosis of leukemia cells. Oral administration of TBE-31 also significantly reduces formation of aflatoxin-DNA adducts and decreases size and number of aflatoxin-induced preneoplastic hepatic lesions in rats by >90%. Because of the two cyano enones in rings A and C, TBE-31 may directly interact with DTT and protein targets such as Keap1 that contain reactive cysteine residues. The above findings suggest that TBE-31 should also be tested for chemoprevention and chemotherapy in relevant models of cancer and against other chronic, degenerative diseases in which inflammation and oxidative stress contribute to disease pathogenesis.

Topics: Administration, Oral; Aflatoxin B1; Animals; Apoptosis; Cell Differentiation; Cell Proliferation; Cell Transformation, Neoplastic; Cells, Cultured; DNA Adducts; Heme Oxygenase-1; Humans; Imidazoles; Leukemia; Liver Neoplasms; Macrophages; Male; Mice; Molecular Structure; NAD(P)H Dehydrogenase (Quinone); Nitric Oxide; Nitric Oxide Synthase Type II; Oleanolic Acid; Phenanthrenes; Rats; Rats, Inbred F344; Reactive Oxygen Species

Polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines (HCAs) ingested with food have repeatedly been suggested to be involved in the malignant transformation of colon epithelial cells. In order to test this hypothesis, HCEC cells (SV40 large T antigen-immortalized human colon epithelial cells) were incubated with a racemic mixture of benzo[c]phenanthrene dihydrodiol epoxides (B[c]PhDE), extremely potent carcinogenic PAH metabolites in vivo, or with 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP), the N-hydroxylated metabolite of the most abundant HCA in cooked meat. First, it was shown that HCEC cells express sulfotransferase 1A1, which is needed to metabolize N-OH-PhIP to the corresponding N-sulfonyloxy derivative, the direct precursor molecule of genotoxic nitrenium ions. Thereafter, exponentially growing HCEC cells were exposed five times to 0.1 microg (0.37 nmol) B[c]PhDE/ml for 30 min or 0.72 microg (3 nmol) N-OH-PhIP/ml for 24 h. Chemically treated HCEC cells showed an enhanced saturation density and grew faster than the corresponding solvent-treated cell cultures. After five treatment cycles, HCEC(B[c]PhDE) as well as HCEC(N-OH-PhIP) cells lost cell-cell contact inhibition and started piling up and forming foci in the culture flasks. Furthermore, HCEC(B[c]PhDE) and HCEC(N-OH-PhIP) cells were injected i.m. into SCID mice. Within 6 weeks after injection, eight animals out of eight injected with HCEC(B[c]PhDE) or HCEC(N-OH-PhIP) cells developed tumors at the site of injection, thus demonstrating the high tumorigenic potential of the HCEC(B[c]PhDE) and HCEC(N-OH-PhIP) cell cultures. Taken together, we show for the first time that the abovementioned active PAH metabolites as well as N-OH-PhIP are indeed able to malignantly transform human colon epithelial cells in vitro.

Topics: Animals; Blotting, Western; Carcinogens; Cell Proliferation; Cell Transformation, Neoplastic; Colon; Dimethyl Sulfoxide; Epithelial Cells; Epoxy Compounds; Humans; Imidazoles; Immunohistochemistry; Mice; Mice, SCID; Phenanthrenes; Pyridines

Salvia miltiorrhiza is a traditional Chinese medicine which has been well documented for its anti-cancer effects. Based on the structure of danshinone, one of the active compounds derived from Salvia miltiorrhiza, we synthesized a simplified phenolic analog, S-3-1, and tried to explore its possible actions in preventing the development of cancer. With the Ames test, S-3-1 was found to efficiently suppress the mutagenicity of benzo[alpha]pyrene. This result is consistent with the inhibitory effect of S-3-1 on the activation of benzo[alpha]pyrene by hepatic microsomal enzymes. Besides the anti-initiation effects, S-3-1 could significantly inhibit the croton oil-induced increase of mouse skin epithermal ornithine decarboxylase activity. Moreover, S-3-1 quenched both superoxide and hydroxyl free radicals whereas it inhibited lipid peroxidation in the in vitro model. These results suggest that S-3-1 might act as anti-initiation and anti-promotion agents through reversing the biochemical alterations induced by carcinogen during carcinogenesis. Therefore, we further investigated the effects of S-3-1 on carcinogenesis. In vitro, S-3-1 inhibited the benzo[alpha]pyrene-induced transformation of V79 Chinese hamster lung fibroblasts. At 10-40 mg/kg, S-3-1 was found to inhibit the development of DMBA/croton oil-induced skin papilloma in mice through decreasing the incidence of papilloma, prolonging the latent period of tumor occurrence and reducing tumor number per mouse in a dose-dependent manner. We concluded from this study that S-3-1 might be developed as a new chemopreventive drug.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Anticarcinogenic Agents; Benzo(a)pyrene; Benzofurans; Bepridil; Biphenyl Compounds; Cell Transformation, Neoplastic; Cells, Cultured; Cricetinae; Croton Oil; Cysteine; Disease Models, Animal; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Epithelial Cells; Fibroblasts; Free Radical Scavengers; Hypoxanthine; In Vitro Techniques; Iron; Lipid Peroxidation; Lung; Male; Medicine, Chinese Traditional; Mice; Mice, Inbred ICR; Microsomes, Liver; Molecular Structure; Mutagens; Ornithine; Ornithine Decarboxylase; Papilloma; Pentetic Acid; Phenanthrenes; Picrates; Plants, Medicinal; Rats; Salmonella; Skin; Skin Neoplasms; Spectrometry, Mass, Electrospray Ionization; Structure-Activity Relationship; Xanthine Oxidase

We have shown that the oval cell line OC/CDE 22 can be transformed by the highly carcinogenic fjord-region diol epoxides of benzo[c]phenanthrene. Mutational activation of the ras proto-oncogene family has been proposed to be a critical event in the formation of tumors induced by polycyclic aromatic hydrocarbons. Therefore, we investigated whether in the earlier transformed OC/CDE 22 cells any point mutations were detected in the ras proto-oncogene. The results indicate that the malignant transformation of OC/CDE 22 cells by the 4 stereoisomeric benzo[c]phenanthrene diol epoxides in vitro is independent of activation of the Ha-ras proto-oncogene. In addition, Northern and Western blot analyses revealed no overexpression of the Ha-ras protooncogene in the transformed OC/CDE 22 cell lines. However, transfection of the OC/CDE 22 cells with an activated Ha-ras oncogene malignantly transformed the OC/CDE 22 cells, and the transfected cells served as precursor cells of tumors with a cholangiocellular morphology and phenotype. Our latter finding reinforces the view that OC/CDE 22 cells are committed to the bile duct epithelial cell lineage.

Topics: Animals; Bile Ducts; Carcinogens; Carcinoma; Cell Differentiation; Cell Line; Cell Lineage; Cell Transformation, Neoplastic; Epithelial Cells; Gene Expression Regulation, Neoplastic; Genes, ras; Humans; Liver; Liver Neoplasms, Experimental; Neoplasm Transplantation; Neoplastic Stem Cells; Phenanthrenes; Proto-Oncogene Mas; Rats; Rats, Sprague-Dawley; Transfection; Urinary Bladder Neoplasms

In previous work we established the rat liver oval cell line OC/CDE 22 in order to study in vitro mechanisms of liver cell transformation. We have now exposed OC/CDE 22 cells to each of the four optically active fjord region dihydrodiol epoxides of benzo[c]phenanthrene to investigate their capacity for malignant transformation of liver cells. All four configurational isomers, which are among the most potent carcinogenic metabolites of polycyclic aromatic hydrocarbons tested in murine tumour models, malignantly transform OC/CDE 22 cells at a 2 microM dose level, resulting in a similar colony-forming efficiency in soft agar. Inoculation of the transformed cells into newborn syngeneic rats produced an extremely high incidence of carcinomas with a short latency period. The induced carcinomas displayed cholangiocellular, adenoid and solid growing structures. Neither cell growth in soft agar nor induction of tumor formation in newborn rats were achieved if confluent OC/CDE 22 cell cultures were exposed to each of the four stereoisomers and left in the confluent state for 4 weeks. In contrast, if confluent cells were exposed to the four stereoisomers, immediately split and then subcultured as usual, full transformation was accomplished. Our results indicate that the fjord region dihydrodiol epoxides of benzo[c]phenanthrene are highly efficient transforming agents for rat liver cells and that proliferation plays a pivotal role in the liver cell transformation process induced by polycylic aromatic hydrocarbons.

Topics: Animals; Carcinogens; Cell Division; Cell Transformation, Neoplastic; Liver; Liver Neoplasms, Experimental; Phenanthrenes; Precancerous Conditions; Rats; Rats, Sprague-Dawley; Stereoisomerism; Tumor Cells, Cultured

Estradiol is converted to catechol estrogens via 2- and 4-hydroxylation by cytochrome P450 enzymes. 4-Hydroxyestradiol elicits biological activities distinct from estradiol, most notably an oxidant stress response induced by free radicals generated by metabolic redox cycling reactions. In this study, we have examined 2- and 4-hydroxylation of estradiol by microsomes of human uterine myometrium and of associated myomata. In all eight cases studied, estradiol 4-hydroxylation by myoma has been substantially elevated relative to surrounding myometrial tissue (minimum, 2-fold; mean, 5-fold). Estradiol 2-hydroxylation in myomata occurs at much lower rates than 4-hydroxylation (ratio of 4-hydroxyestradiol/2-hydroxyestradiol, 7.9 +/- 1.4) and does not significantly differ from rates in surrounding myometrial tissue. Rates of myometrial 2-hydroxylation of estradiol were also not significantly different from values in patients without myomata. We have used various inhibitors to establish that 4-hydroxylation is catalyzed by a completely different cytochrome P450 than 2-hydroxylation. In myoma, alpha-naphthoflavone and a set of ethynyl polycyclic hydrocarbon inhibitors (5 microM) each inhibited 4-hydroxylation more efficiently (up to 90%) than 2-hydroxylation (up to 40%), indicating > 10-fold differences in Ki (<0.5 microM vs. > 5 microM). These activities were clearly distinguished from the selective 2-hydroxylation of estradiol in placenta by aromatase reported previously (low Km, inhibition by Fadrozole hydrochloride or ICI D1033). 4-Hydroxylation was also selectively inhibited relative to 2-hydroxylation by antibodies raised against cytochrome P450 IB1 (rat) (53 vs. 17%). These data indicate that specific 4-hydroxylation of estradiol in human uterine tissues is catalyzed by a form(s) of cytochrome P450 related to P450 IB1, which contribute(s) little to 2-hydroxylation. This enzyme(s) is therefore a marker for uterine myomata and may play a role in the etiology of the tumor.

Topics: Benzoflavones; Cell Transformation, Neoplastic; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Enzyme Inhibitors; Estradiol; Estrogens, Catechol; Female; Humans; Hydroxylation; Leiomyoma; Microsomes; Myometrium; Naphthalenes; Phenanthrenes; Placenta; Pregnancy; Uterine Neoplasms

The differentiation-inducing activity of tanshinone (TAN) and all-trans-retinoic acid (RA) was studied in vitro on a human cervical carcinoma cell line, ME180. The tumor cells were treated with TAN or RA in DMSO (final concentration 0.02%, V/V) on 4 successive days. Cells treated with the same concentration of DMSO alone served as control. Morphologic studies with light and transmission electron microscopy showed that the cells treated with both TAN and RA became well-differentiated. The cell growth, (as revealed by cell counting and 3H-TdR incorporation) was inhibited and the tumorigenicity in nude mice was reduced. No significant difference was observed between the cells treated with TAN and RA.

Topics: Abietanes; Animals; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Cell Transformation, Neoplastic; Female; Humans; Mice; Mice, Nude; Phenanthrenes; Tretinoin; Tumor Cells, Cultured; Uterine Cervical Neoplasms

Two nitroaromatics, 6-nitrobenzo[a]pyrene (6-N-BaP) and 6-nitrochrysene (6-N-CRY), and the corresponding parent hydrocarbons, benzo[a]pyrene (BaP) and chrysene (CRY), were studied in in vitro transformation assays with Syrian hamster embryo (SHE) cells, BALB/3T3 and C3H10T1/2 mouse cell lines. The three cell systems showed different sensitivities to the transforming effects of the chemicals studied, SHE cells being the most efficient, followed by 3T3 cells and the last being C3H10T1/2 cells. In the SHE cell system all compounds were active. Considering the concentrations (in microM) and the transformation frequency BaP was the most active, followed by 6-N-BaP, 6-N-CRY and CRY. In the BALB/3T3 standard assay and in the C3H10T1/2 assay only BaP was clearly active. When used as initiators 6-N-BaP and 6-N-CRY were inactive in the C3H cell system. In conclusion 6-N-BaP appears less active in in vitro systems than the parent compound BaP; 6-N-CRY is probably negative since it is questionable in vitro and negative in mouse skin.

Topics: Animals; Benzopyrenes; Carcinogens; Cell Survival; Cell Transformation, Neoplastic; Cells, Cultured; Chrysenes; Cricetinae; Dose-Response Relationship, Drug; Phenanthrenes; Tetradecanoylphorbol Acetate

The syn- and anti-isomers of the bay-region diol-epoxides of chrysene and of 3-hydroxychrysene and their metabolic precursors have been investigated for mutagenicity in Salmonella typhimurium (reversion to histidine prototrophy) and V79 Chinese hamster cells (acquirement of resistance to 6-thioguanine) and for transforming activity in M2 mouse prostate cells. Other known and potential chrysene metabolites have been included in mutagenicity experiments. Direct mutagenic activity in S. typhimurium TA 100 exhibited, in order of potency, anti-triol-epoxide greater than syn-triol-epoxide greater than anti-diol-epoxide greater than syn-diol-epoxide greater than chrysene 5,6-oxide much greater than chrysene-1,2-quinone, chrysene-3,4-quinone, and chrysene 5,6-quinone. Chrysene, the six isomeric chrysenols, and the trans-dihydrodiols [trans-1,2-dihydroxy-1,2-dihydrochrysene (chrysene-1,2-diol), trans-3,4-dihydroxy-3,4-dihydrochrysene, trans-5,6-dihydroxy-5,6-dihydrochrysene, and 9-hydroxy-trans-1,2-dihydroxy-1,2-dihydrochrysene (9-hydroxychrysene-1,2-diol)] were inactive per se but were activated to mutagens in the presence of reduced nicotinamide adenine dinucleotide phosphate-fortified postmitochondrial fraction (S9 mix) of liver homogenate from Arochlor 1254-treated rats. Chrysene, 3-hydroxychrysene, chrysene-1,2-diol, and 9-hydroxychrysene-1,2-diol were activated efficiently; the other compounds were activated weakly. In S. typhimurium TA 98, the mutagenic activities of the chrysene derivatives were weak in comparison with those in the strain TA 100. trans-3,4-Dihydroxy-3,4-dihydrochrysene (in the presence of S9 mix) was the most efficacious mutagen in strain TA 98. The relative mutagenic potencies of the directly active compounds differed from the results obtained in strain TA 100, in that in strain TA 98 the anti-diol-epoxide was more mutagenic than the triol-epoxides and chrysene 5,6-oxide was more mutagenic than syn-diol-epoxide and syn-triol-epoxide. In V79 cells, the order of mutagenic potency was: anti-triol-epoxide greater than anti-diol-epoxide greater than syn-triol-epoxide greater than syn-diol-epoxide greater than chyrsene 5,6-oxide greater than chrysene-1,2-diol (in the presence of S9 mix) greater than 9-hydroxychrysene-1,2-diol (in the presence of S9 mix) greater trans-3,4-dihydroxy-3,4-dihydrochrysene in the presence of S9 mix). Chrysene, 3-hydroxychrysene, 5-hydroxychrysene, and 6-hydroxychrysene showed no mutagenic effects in V79 cells, either

Topics: Animals; Biotransformation; Cell Transformation, Neoplastic; Cells, Cultured; Chrysenes; Cricetinae; Epoxy Compounds; Isomerism; Male; Mice; Microsomes, Liver; Mutagenicity Tests; Mutagens; Phenanthrenes; Prostate; Rats; Salmonella typhimurium

The cyclopenta(a)phenanthrene, 15,16-dihydro-11-methyl-cyclopenta(a)phenanthren-17-one, had potent mutagenic activity in cell-mediated mutation assays with V79 Chinese hamster cells as targets, and cells of the human hepatoma line HepG2 as mediators of activation. The compound was inactive when low-passage hamster embryo cells were used as activators. When the mutagenic activity of a series of cyclopenta(a)phenanthrenes was compared in mutation assays with HepG2 cells as activators, there was a good correlation between mutagenic activity in this system and carcinogenic activity in mouse skin in vivo. One exception was a noncarcinogenic compound, which is mutagenic in the Ames' test, and was also mutagenic in the mammalian cell assay.

Topics: Animals; Carcinoma, Hepatocellular; Cell Line; Cell Transformation, Neoplastic; Clone Cells; Cricetinae; Cricetulus; Humans; Liver Neoplasms; Lung; Mutagenicity Tests; Phenanthrenes

Topics: Adenoviridae; Animals; Benz(a)Anthracenes; Benzopyrenes; Cell Survival; Cell Transformation, Neoplastic; Cells, Cultured; Cricetinae; Embryo, Mammalian; Hydrocarbons; Methylcholanthrene; Oncogenic Viruses; Phenanthrenes; Polycyclic Compounds; Stimulation, Chemical

Topics: Animals; Benz(a)Anthracenes; Carcinogens; Cell Transformation, Neoplastic; Cells, Cultured; Clone Cells; Cricetinae; Embryo, Mammalian; Ethers, Cyclic; Female; In Vitro Techniques; Methylcholanthrene; Phenanthrenes; Polycyclic Compounds; Pregnancy; Rats

Topics: Aflatoxins; Animals; Azo Compounds; Carcinogens; Cell Line; Cell Transformation, Neoplastic; Cells, Cultured; Cricetinae; Embryo, Mammalian; Fluorenes; Nitrosamines; Nitrosoguanidines; Phenanthrenes; Urethane

Topics: Animals; Benz(a)Anthracenes; Cell Transformation, Neoplastic; Clone Cells; Ethers, Cyclic; Hydroxylation; In Vitro Techniques; Male; Methylcholanthrene; Mice; Mice, Inbred Strains; Neoplasms, Experimental; Phenanthrenes; Prostate; Structure-Activity Relationship

Topics: Animals; Benz(a)Anthracenes; Carcinogens; Cell Line; Cell Transformation, Neoplastic; Clone Cells; Cricetinae; DNA; Ethers, Cyclic; Glycols; Kidney; Phenanthrenes; Phenols; Proteins; RNA; Tritium

Topics: Aflatoxins; Animals; Azo Compounds; Benzopyrenes; Bronchial Neoplasms; Carcinogens; Cell Transformation, Neoplastic; Humans; Iron; Liver; Massachusetts; Metals; Neoplasms, Experimental; Phenanthrenes; Polycyclic Compounds; Tracheal Neoplasms; United States