methylnitronitrosoguanidine and Lung-Neoplasms

Dietary factors are now considered to be among the most important environmental risk determinants for cancer. In addition to epidemiological studies, experimental animal studies are an important tool to investigate dietary modulation in carcinogenesis. Results of recent experimental studies on the effect of some nutrients indicate that vitamin A did show an inverse relation with the occurrence of preneoplastic respiratory lesions but not with respiratory tract tumors in benzo[a]pyrene-induced respiratory carcinogenesis. Dietary fat increases respiratory tract tumors and preneoplastic lesions. In colon carcinogenesis, a fat-fiber interrelation was noticed in 1,2-dimethyl-hydrazine- and N-methyl-N'-nitro-N-nitrosoguanidine-induced tumors. Preliminary results in prostate carcinogenesis indicate that dietary fat did not influence the incidence of prostate cancer in a recently developed rat model. Some possible mechanisms in colon and prostate carcinogenesis are discussed.

Topics: 1,2-Dimethylhydrazine; Androgens; Animals; Benzo(a)pyrene; Colonic Neoplasms; Diet; Dietary Fats; Dietary Fiber; Dietary Proteins; Dimethylhydrazines; Disease Models, Animal; Drug Synergism; Epidemiologic Methods; Humans; Lung Neoplasms; Male; Methylnitronitrosoguanidine; Models, Biological; Prostatic Neoplasms; Vitamin A

Topics: 9,10-Dimethyl-1,2-benzanthracene; Adenocarcinoma; Animals; Cricetinae; Disease Models, Animal; Dogs; Drug Interactions; Guinea Pigs; Haplorhini; Kidney Neoplasms; Liver Neoplasms; Liver Neoplasms, Experimental; Lung Neoplasms; Methylcholanthrene; Methylnitronitrosoguanidine; Mice; Neoplasms, Experimental; Rabbits; Rats; Stomach Neoplasms; Urinary Bladder Neoplasms

The chemical class of drugs known as the nitrosoureas are a recently developed group of very active alkylating-agent anticancer drugs which are best represented by BCNU, CCNU, and methyl-CCNU (meCCNU). The nitrosoureas are among the most active, if not the most active, anticancer drugs both quantitatively (log kill of sensitive tumor cells in vivo) and qualitatively (spectrum of mouse, rat, and hamster tumors responding to treatment). Therapeutic anticancer activity of the nitrosoureas has been consistently observed with oral as well as parenteral administration. The nitrosoureas are clearly the most active group of anticancer drugs observed against experimental meningeal leukemias and intracerebrally implanted transplantable primary tumors of central nervous system origin (eg, gliomas, ependymoblastomas, and astrocytomas in mice and hamsters). The nitrosoureas have been observed to be less than additive in lethal toxicity for vital normal cells in the mouse in combination with representatives of the other major classes of anticancer agents, eg, purine antagonists, pyrimidine antagonists, inhibitors of DNA polymerase(s) or ribonucleotide reductase(s), mitotic inhibitors, drugs that bind to or intercalate with DNA, and other alkylating agents. Therapeutic synergism against one or more transplantable or spontaneous tumors of mice, rats, or hamsters with one of several nitrosoureas in two-drug combinations with representatives of most of the major classes of anticancer agents listed above has been reported. With a number of advanced-stages mouse tumors, generally considered to be refractory to treatment with most anticancer agents, long-term cures have been obtained with combination-drug or combined-modality (surgery plus chemotherapy) treatment. The demonstrated lack of cross-resistance of several leukemias and solid tumors of mice selected for resistance to BCNU, meCCNU, or other alkylating agents suggests that the widely held opinion that all alkylating agents are very similar in biologic mechanism of action, and therefore resistance to one alkylating agent probably predicts cross-resistance to all alkylating agents, may no longer be tenable. If not, then alkylating-agent drug combinations, either used alone or combined with other treatment modalities (eg, surgery) which have been reported to result in therapeutic improvement in a number of experimental murine tumor systems, may be indicated for serious consideration as surgical adjuvant chemotherapy by s

Topics: Animals; Carmustine; Colonic Neoplasms; Drug Evaluation, Preclinical; Drug Resistance; Drug Therapy, Combination; Leukemia L1210; Lomustine; Lung Neoplasms; Mammary Neoplasms, Experimental; Melanoma; Methylnitronitrosoguanidine; Methylnitrosourea; Mice; Neoplasms, Experimental; Nitrosourea Compounds; Semustine

The present survey deals with requirements the experimental-oncological models used in morphogenetic investigations should meet. Data on ways of inducing tumours of various organs the most suited for such investigations are presented. The available at present literature comprises data on different variants of morphogenesis of tumours; in a number of cases malignant neoplasms can develop against the background of an unchanged structure without previous alterations. Because of a contradictory character of the literature reports on morphogenesis of tumours, further investigations into the morphodynamics of the process of cancerogenesis are needed; at present, this may be successfully implemented if adequate models of the majority of tumour diseases in man are available. These studies are of importance for better understanding of pathogenesis or tumour growth and for ascertaining the concept of precancer changes.

Topics: 2-Acetylaminofluorene; 9,10-Dimethyl-1,2-benzanthracene; Aflatoxins; Animals; Azoxymethane; Benzopyrenes; Brain Neoplasms; Carcinogens; Cricetinae; Dimethylhydrazines; Dogs; Esophageal Neoplasms; Ethionine; Ethylnitrosourea; Female; Hematopoietic System; Intestinal Neoplasms; Liver Neoplasms; Lung Neoplasms; Male; Mammary Neoplasms, Experimental; Methylnitronitrosoguanidine; Methylnitrosourea; Mice; Neoplasms, Experimental; Nitrosamines; Nitroso Compounds; Nitrosoguanidines; o-Aminoazotoluene; p-Dimethylaminoazobenzene; Precancerous Conditions; Rats; Skin Neoplasms; Stomach Neoplasms; Urinary Bladder Neoplasms

Selpercatinib has been approved by most major regulatory bodies in 2020 and become the standard therapy for rearranged during transfection ( RET )-rearranged nonsmall-cell lung cancer (NSCLC). Knowledge is limited regarding mechanisms of resistance to selpercatinib and effective treatment. One study identified MNNG HOS transforming ( MET ) amplification as intrinsic or secondary resistance mechanism from four patients, and three of them showed ~40% tumor reduction when treated with selpercatinib plus crizotinib. We report a 30-year-old female nonsmoker diagnosed in 2019 with stage IV lung adenocarcinoma harboring KIF5B-RET and a novel FOXD1-RET fusion. Frontline therapy consisted of bevacizumab combined with pemetrexed and carboplatin and achieved a progression-free survival (PFS) of 14 months with best response of stable disease. The patient then enrolled in the LIBRETTO-321 trial (NCT03157129) and started selpercatinib, which elicited a PFS of 9 months with best response of partial response. MNNG HOS transforming ( MET ) amplification was subsequently detected upon progression on selpercatinib, and the patient was placed on third-line treatment with selpercatinib plus crizotinib. However, her health deteriorated rapidly and died of cancer 4 months later. We provided additional evidence supporting MET amplification as an acquired mechanism of resistance to selective RET inhibition. In addition, the apparent lack of response to selpercatinib plus crizotinib in this case highlights the need for future cohort studies for examining the value of combining RET and MET inhibitors in treating RET -rearranged, MET -amplified NSCLC.

Topics: Adult; Carcinoma, Non-Small-Cell Lung; Crizotinib; Female; Forkhead Transcription Factors; Humans; Lung Neoplasms; Methylnitronitrosoguanidine; Protein Kinase Inhibitors; Pyrazoles; Pyridines; Transfection

DNA damage or mutation in cells contributes to tumorigenesis. The transcription factor FOXO1 modulates the expression of genes involved in DNA damage repair, cell cycle arrest and apoptosis. The transcriptional activity of FOXO1 is fundamentally regulated by post-translational modification and subcellular localization. H1299 lung cancer cells were treated with the alkylating agent MNNG, and the cell viability and DNA damage were separately determined by MTT and comet assay. Using immunofluorescence and western blotting, we observed the subcellular localization of FOXO1 and measured the relevant protein expression levels, respectively. To examine cell cycle arrest and apoptosis, flow cytometry analysis was preformed. The interaction between FOXO1 and JNK was analyzed through immunoprecipitation. Our results showed that cell viability was reduced at 24 h after MNNG treatment, and appeared to recover to some degree at 48 h. The increased expression and nuclear export of FOXO1 emerged at 4 h after the treatment. Nuclear FOXO1 played a pivotal role in cell cycle arrest, apoptosis and DNA damage repair by upregulating p27(Kip1), Bim and GADD45 gene expression, respectively. AKT-dependent S256 phosphorylation of FOXO1 and the S473 phosphorylation of AKT were both enhanced following DNA damage. Moreover, our studies revealed that FOXO1 directly interacted with JNK, and the inhibition of the JNK activity led to decreased expression of FOXO1 target genes. These findings suggest for the first time that FOXO1 is a promising candidate substrate for JNK, and the FOXO1-dependent DNA damage repair may be regulated positively by the JNK pathway in H1299 lung cancer cells.

Topics: Anthracenes; Apoptosis Regulatory Proteins; Bcl-2-Like Protein 11; Cell Cycle Proteins; Cell Line, Tumor; Cell Survival; Cyclin-Dependent Kinase Inhibitor p27; DNA Damage; DNA Repair; Forkhead Box Protein O1; Forkhead Transcription Factors; G2 Phase Cell Cycle Checkpoints; Gene Expression; Gene Expression Regulation, Neoplastic; Humans; JNK Mitogen-Activated Protein Kinases; Lung Neoplasms; Membrane Proteins; Methylnitronitrosoguanidine; Nuclear Proteins; Phosphorylation; Protein Processing, Post-Translational; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Signal Transduction; Transcription, Genetic; Transcriptional Activation

Studies were carried out to ascertain the efficacy of mild whole body hyperthermia (WBH) as a modifier of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) cytotoxicity in mice. Adult Swiss male mice, 6-8 weeks old, weighing about 25 g were exposed to mild WBH (39 degrees C, 1 h) in a precision temperature controlled environmental chamber maintained at 50-60% relative humidity. Twenty-four hours after treatment, animals were administered with different doses of MNNG either by intraperitoneal (i.p.) injections or by feeding through drinking water and were monitored for survival. The studies revealed that the exposure of animals to mild WBH, 24 h prior to MNNG administration results in an increase in survival and recovery in mean body weight compared with those administered with MNNG only. This suggests that prior WBH treatment can effectively reduce the MNNG cytotoxicity in mice.

Topics: Animals; Body Weight; Carcinogens; Cell Survival; Drinking; Hypothermia, Induced; Intestinal Neoplasms; Lung Neoplasms; Methylnitronitrosoguanidine; Mice; Splenomegaly; Time Factors

Lung tumors frequently exhibit altered expression of oncogenes and/or tumor suppressor genes. Although some of these alterations are believed to arise from chemical exposure, the ability of specific chemicals to cause distinct changes in gene expression is not well characterized. We previously reported the development of a quantitative reverse transcriptase/polymerase chain reaction (RT/PCR) method for measuring c-myc mRNA levels, and reported that c-myc proto-oncogene expression is significantly increased in small-cell lung carcinoma cells. In the present study, quantitative RT/PCR was used to assess the effect of model toxins cycloheximide (CHX), a protein synthesis inhibitor, and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a DNA alkylating agent, on c-myc mRNA levels in normal human bronchial epithelial (NHBE) and lung adenocarcinoma (A549) cells. Expression of c-myc was evaluated at 1-100 microM CHX and MNNG and was compared to the cytotoxic response as measured by the neutral red assay. Cycloheximide elicited a dose-dependent increase in c-myc mRNA levels in NHBE and A549 cells, but did not alter expression of the housekeeping gene beta-actin. A maximum increase for c-myc expression (200% of control) was observed 5 h after treatment with noncytotoxic concentrations. In contrast, MNNG elicited a dose-dependent decrease in c-myc expression in A549 cells, but no significant change in c-myc was observed in NHBE cells. The results from this study suggest that the quantitative RT/PCR method may be an appropriate technique for monitoring gene expression changes following chemical exposure. Hence, these types of studies may assist in the identification of specific chemicals which may induce the genetic alterations involved in the development of lung cancer as well as provide information relevant to the interactive effects of chemicals within complex mixtures.

Topics: Actins; Adenocarcinoma; Adult; Bronchi; Carcinogens; Child; Cycloheximide; Dose-Response Relationship, Drug; Gene Expression Regulation, Neoplastic; Genes, myc; Humans; Lung Neoplasms; Male; Methylnitronitrosoguanidine; Proto-Oncogene Mas; Proto-Oncogene Proteins c-myc; Respiratory Mucosa; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tumor Cells, Cultured

The concept of hormesis (i.e., low-dose stimulation/high-dose inhibition) has been shown to be widely generalizable with respect to chemical class, animal model, gender, and biological end point. The public health implication of this lack of linearity in the low-dose area of the dose-response curve raises the question of whether low doses of carcinogens will reduce cancer risk. Articles relating to the process of carcinogenesis (i.e., initiation, promotion, tumor development, and progression) were obtained from a recently developed chemical hormesis database and evaluated for their evidence of hormesis. Numerous examples in well-designed studies indicate that U- or J-shaped dose-response relationships exist with respect to various biomarkers of carcinogenesis in different animal models of both sexes. Examples of such J-shaped dose-response relationships in each stage of the process of carcinogenesis were selected for detailed toxicological examination. These results have important implications for both the hazard assessment of carcinogens and cancer risk assessment procedures.

Topics: Animals; Caffeic Acids; Carcinogenicity Tests; Carcinogens; Cell Division; Dioxins; DNA Ligases; Dose-Response Relationship, Drug; Environmental Pollutants; Female; Humans; Hyperplasia; Keratinocytes; Kidney; Liver; Lung Neoplasms; Male; Mercury; Methylnitronitrosoguanidine; Neoplasms, Radiation-Induced; Phenobarbital; Polychlorinated Dibenzodioxins; Rats; Rats, Sprague-Dawley; Risk Assessment; Saccharin; Stomach; Testicular Neoplasms; Urinary Bladder; Urinary Bladder Neoplasms

A human lung cancer cell line (A549) mutant with hypoxanthine guanine phosphoribosyltransferase (HGPRT) deficiency and resistance to 8-AG was established by treatment of the A549 cells with 3 micrograms.ml-1 N-methyl-N'-nitro-nitrosoguanidine (MNNG), and prescreened in 0.25% agarose DMEM semisolid medium containing 20 micrograms.ml-1 8-AG. The mutant cells are resistant to cytotoxic effect of 8-AG and sensitive to hypoxanthine-aminopterin thymidine (HAT) selective medium. The mutant cells can be used as a candidate parental cells to fuse with the somatic cells.

Topics: Antimetabolites, Antineoplastic; Azaguanine; Cell Fusion; Cell Line, Transformed; Drug Resistance, Neoplasm; Humans; Hypoxanthine Phosphoribosyltransferase; Lung Neoplasms; Methylnitronitrosoguanidine; Mutation; Tumor Cells, Cultured

The effects of sodium arsenite (As) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) on epithelia of human fetal trachea and bronchiolar epithelia of human fetal lung were studied by using organ-cultured explants. In epithelium of human fetal trachea, 34 microM MNNG induced hyperplasia, metaplasia, and dysplasia; 1 microM As induced hyperplasia; and 3-9 microM As induced hyperplasia and cellular atypia. In glandular epithelium of human fetal trachea, 34 microM MNNG induced hyperplasia and metaplasia; 1 microM As did not induce obvious changes; and 3-9 microM As induced hyperplasia and epidermoid metaplasia with nuclear atypia. In bronchiolar epithelium of human fetal lung, the induction of dysplasia was observed for 1 microM As. Arsenic-induced preneoplastic lesions support the conclusion of epidemiological studies that arsenic is carcinogenic to human lung.

Topics: Arsenites; Bronchi; Epithelium; Fetus; Humans; Hyperplasia; Lung; Lung Neoplasms; Methylnitronitrosoguanidine; Organ Culture Techniques; Precancerous Conditions; Sodium Compounds; Trachea; Tracheal Neoplasms

Three hundred and ninety LACA mice of seven weeks old were used in 2 batches (96.4 wks and 106 wks) for studying the preventive effect of green tea on MNNG-induced lung cancers and precancerous lesions. These mice (within each batch) were randomly allocated to four groups, namely, positive control (MNNG), green tea (GT), complex (MNNG + GT), and blank control (C) group. In MNNG group, MNNG 250 micrograms) was injected intravenously every five days for seven times in each mouse; the total dosage of MNNG was 1.75mg. In GT group, according to W/W, 5% GT dust was well mixed into 95% common diet for long-term breeding. In complex group, MNNG was given as that in MNNG group and the mice were reared as those in GT group. The mice in MNNG group and in C group were all reared by common diet. The mean amount of daily intake of feed was 10g. The number of effective animals was 354. The results of experiments showed different degrees of preventive effect of green tea on MNNG-induced lung cancers and precancerous lesions in LACA mice. Green tea exerted an effect on the number of induced cancers and precancerous lesions, causing a drop of the cancerous rate from 79.75% to 13.59% and the number of lung tumor down to 1/7-1/16 that of the MNNG group, i.e. down to less than one tumor nodule per mouse.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adenoma; Animals; Lung Neoplasms; Methylnitronitrosoguanidine; Mice; Plant Extracts; Precancerous Conditions; Tea

550 seven-wk-old LACA mice were used in 3 batches for studying the inhibitory effect of refined Amorphophallus konjac (Konjaku powder) on MNNG-induced lung cancers. The mice (within each batch) were randomly allocated into four groups, namely, positive control (MNNG), Amorphophallus konjac (A. K.), complex (MNNG+A. K.), and blank control (C) groups. In MNNG group, MNNG (250 micrograms) was injected intravenously once every five days for seven times in each mouse, the total dosage of MNNG being 1.75 mg. In A. K. group, according to w/w, 8% A. K. was well mixed into 92% common diet for long-term breeding. In the complex group, MNNG was given as that in MNNG group and the mice were kept as those in A. K. group. The mice in MNNG group and in C group were all maintained on common diet. The results showed different degrees of inhibitory and preventive effect of refined A. K. on MNNG-induced lung cancers. Refined A. K. not only exerted effect on the number of induced cancer and precancerous lesions, causing a drop in cancer rate from 70.87% to 19.38% and the mean number of cancer and precancerous lesions in each animal, but also altered the constituent ratio of the kinds of tumors, showing a decrease in malignancy (adenoma with malignant change), absence of adenocarcinoma, and relative increase in benign adenoma. The results of experiments in 3 batches also exhibited good reproducibility as well as absence of adverse reaction to Konjaku powder.

Topics: Adenocarcinoma; Adenoma; Animals; Dietary Fiber; Female; Lung Neoplasms; Male; Mannans; Methylnitronitrosoguanidine; Mice; Precancerous Conditions

Squamous cell carcinomas (SCC) of the mouse skin were produced by three different protocols of chemical carcinogenesis, i.e., complete carcinogenesis with 7,12-dimethylbenz(a)anthracene (DMBA) two-stage carcinogenesis with DMBA as initiator, 12-O-tetradecanoyl-phorbol-13-acetate (TPA) as promoter and three stage carcinogenesis with DMBA, TPA and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) as third-stage agent or progressor. Tumors were sequentially studied at weeks 38-52 of treatment. Although no significant differences in the rate of appearance of gamma-glutamyl transpeptidase (GGT) could be seen, a larger number of SCC produced by complete carcinogenesis protocols were GGT-negative. This coincided with the higher grade of malignancy of these tumors as evaluated by histopathology. In general terms high-grade tumors were seen more frequently in the complete carcinogenesis experiment than in the other two protocols. SCC produced by complete carcinogenesis also exhibited a markedly higher DNA index than the SCC from the other experimental groups. All three protocols were very effective in producing late metastasizing tumors, and no significant differences could be established in the incidence of spontaneous lung metastasis. This shows that, contrary to general knowledge, if adequately observed for more than 40 weeks, SCC of the murine skin is able to metastasize in the lung in approximately 30% of cases. Nevertheless, complete carcinogenesis-induced SCC were usually of higher histological grade, a proportion of these were GGT-negative and produced more multiple or diffuse metastases than the tumors induced by the multistage protocols.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Carcinoma, Squamous Cell; DNA, Neoplasm; Female; gamma-Glutamyltransferase; Lung Neoplasms; Methylnitronitrosoguanidine; Mice; Neoplasm Metastasis; Skin Neoplasms; Tetradecanoylphorbol Acetate; Time Factors

Three hundred and seventy LACA mice of seven weeks old were used in 2 batches for studying the prophylactic effect of Konjaku powder on MNNG-induced lung cancers. These mice (within each batch) were randomly allocated to four groups, namely positive control (MNNG), refined Amorphophallus Konjac (R.A.K.), complex (MNNG + R.A.K.), and blank control (C). In MNNG group, MNNG (250 micrograms) was injected intravenously once five days for seven times in each mouse, the total dosage of MNNG was 1.75 mg. In R.A.K. group, according to w/w, 8% R.A.K. was well mixed into 92% common diet for long-term term breeding. In complex group, MNNG was given as that in MNNG group and the mice were reared as those in R.A.K. group. The mice in MNNG group and in C group were all reared by common diet. The results of experiments showed different degrees of preventive effect of R.A.K. on MNNG-induced lung cancers in LACA mice. R.A.K. not only exerted effect on the number of induced cancer, causing a drop of the cancerous rate from 79.75% to 20.00% and the mean number of cancer in each animal, but also prolonged the survival time of animals. At the same time, the constituent ratio of the kinds of tumor denoted a decrease in malignancy (adenoma with malignant change), an absence of adenocarcinoma and relative increase in benign adenoma. The results of experiments also exhibited good duplication as well as absence of adverse reactions to Konjaku powder.

Topics: Animals; Lung Neoplasms; Mannans; Methylnitronitrosoguanidine; Mice; Plants, Edible; Polysaccharides

Topics: Adenocarcinoma; Animals; Female; Lung Neoplasms; Methylnitronitrosoguanidine; Mice

N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG) dissolved in distilled water (5 g/l) was administered orally once by gastric tube at a dose of 0.25 ml/10 g body weight to 5-day-old or 28-day-old Wistar Furth (W/Fu) or ACI rats. Gastric tumors in the glandular stomach were found in 58% of 5-day-old ACI rats, but none were found in the rest of the groups. Forestomach tumors were found in both strains of rats at both age groups with incidences of 68-100%. Lung tumors were induced in 64% of 5-day-old and 6% of 28-day-old W/Fu rats, but not in ACI rats. Besides the tumors, a high frequency of hepatic cysts was also noted in ACI rats. Intestinal metaplastic foci with alkaline phosphatase activity were found in the group of 5-day-old ACI rats and none in the rest of the groups. The results showed that the incidences and the locations of tumors in rats induced by MNNG are greatly influenced by both strain and age.

Topics: Age Factors; Animals; Intestinal Neoplasms; Liver Neoplasms; Lung Neoplasms; Methylnitronitrosoguanidine; Mitotic Index; Neoplasms, Experimental; Rats; Rats, Inbred ACI; Rats, Inbred WF; Stomach Neoplasms

The skin of white outbred rats was painted with solutions of N-methyl-N-nitrosourea (MNU), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), N-methyl-N,N'-dinitroguanidine and diazoacetic ester (DAAE). DAAE was administered to rats intravenously, intraperitoneally and subcutaneously as well. Skin tumours have appeared only in the experiments with MNU, MNNG and DAAE. The application of MNU and MNNG caused tumours of the skin in the site of application, and as for DAAE, it induced tumours in the remote places of the skin. Systemic methods of DAAE administration entailed mainly mammary tumours in female rats, but not those of the skin. Possible mechanisms of action of the compounds under study have been discussed.

Topics: Administration, Topical; Animals; Carcinoma, Basal Cell; Diazonium Compounds; Female; Guanidines; Injections, Intraperitoneal; Injections, Intravenous; Injections, Subcutaneous; Lung Neoplasms; Male; Methylnitronitrosoguanidine; Methylnitrosourea; Nitroso Compounds; Rats; Sarcoma, Experimental; Skin Neoplasms

O6-Methylguanine-DNA methyltransferase activity was measured in extracts of human tumor cells and was partially purified from human placenta. Repair of O6-methylguanine in DNA inactivated the methyltransferase, and treatment of cells with MNNG, which produces this alkylated base in DNA, depleted the cells of active methyltransferase. RNA and protein synthesis were required for restoration of methyltransferase activity, which transiently exceeded the original levels by 50% 48 h after treatment. One species of methyltransferase of Mr = 22 kd was present in human tumor cells and human placenta.

Topics: Astrocytoma; Cell Line; Colonic Neoplasms; DNA Repair; Female; Humans; Lung Neoplasms; Methylnitronitrosoguanidine; Methyltransferases; O(6)-Methylguanine-DNA Methyltransferase; Placenta; Pregnancy

By mutagenesis of a cell line derived from Lewis lung carcinoma (3LL), it is possible to obtain at high frequency stable tumor cell variants (tum-) that are rejected by syngeneic mice. The possibility of obtaining a cytolytic T cell (CTL) response directed specifically against these tum- variants was examined. With the four variants that were analysed, a significant cytolytic activity was obtained with peritoneal cells from immune mice collected shortly after an intraperitoneal boost and also with spleen cells after a secondary stimulation in vitro. The CTL populations preferentially lysed the immunizing tum- variant, while also showing a cross-reactive lysis against the other variants and the original 3LL cells. Highly active CTL clones could be isolated from limiting dilution microcultures of these CTL populations. The clonal analysis clearly showed the existence of two distinct CTL populations, one directed exclusively against the immunizing variant and another that lysed all 3LL targets equally. This CTL specificity analysis therefore demonstrates directly the presence of new antigens on the 3LL tum- cell variants.

Topics: Animals; Antigens, Neoplasm; Cell Line; Clone Cells; Epitopes; Lung Neoplasms; Methylnitronitrosoguanidine; Mice; Mice, Inbred C57BL; Neoplasm Transplantation; Neoplasms, Experimental; T-Lymphocytes, Cytotoxic

Using repeated cloning and treatment with cis-HPL (200 micrograms/ml), an analogue of a procollagen precursor inhibitory to the growth of collagen-synthesizing cells of mesenchymal origin, clonally premature epithelial cell lines were isolated from fetal SGH lungs cultured on the 15th day of gestation. One of the cell lines, M3E3/C3, which has been extensively studied for biological characterization, developed poorly differentiated carcinomas in injected hamsters after transformation by MNNG. Moreover, when grown on collagen gel, this cell line indicated an obvious potency for in vitro differentiation in response to vitamin A by developing activated Golgi regions, well developed rER and a number of mucus-like granules. Since such a differentiative responses is expected to be definable in the light of respiratory epithelium developing in utero, this cell line may be useful for studying mechanisms of differentiation-dependent sensitivity of fetal organs to transplacental carcinogen exposure.

Topics: Animals; Cell Line; Cell Transformation, Neoplastic; Cricetinae; Epithelial Cells; Female; Fetus; Hydroxyproline; Lung; Lung Neoplasms; Maternal-Fetal Exchange; Mesocricetus; Methylnitronitrosoguanidine; Pregnancy

Topics: Animals; Carcinoma, Squamous Cell; Eyelid Neoplasms; Female; Heart Neoplasms; Lethal Dose 50; Lung Neoplasms; Male; Methylnitronitrosoguanidine; Neoplasms, Experimental; Rats

It has been reported that, by mutagenesis of a malignant mouse teratocarcinoma cell line, it is possible to obtain cell variants that are incapable of forming progressive tumors in syngeneic mice. These variants, which were called "tum-," are eliminated from the host by an immune rejection process. We report here that similar variant cell clones can be obtained at high frequency from a Lewis lung carcinoma cell line treated with the mutagen N-methyl-N'-nitro-N-nitrosoguanidine. Syngeneic C57BL/6 mice reject these tum- clones and acquire a strong radioresistant immune protection against the immunizing clone. When the challenging tum- clone differs from the immunizing clone, a weaker radioresistant immune protection can be demonstrated with some, but not all, combinations. All the tum- clones induce a significant protection against the original Lewis lung malignant cells. These results imply that each Lewis lung tum- variant carries on its surface a singular antigen in addition to one or more weak antigens already present on the original tumor cell line. This antigenic pattern is similar to that found on teratocarcinoma tum- variants. Our results suggest that the procedure of using a mutagen in order to generate tum- variants carrying new transplantation antigens may be generally applicable to cancer cells.

Topics: Animals; Cell Line; Genetic Variation; Lung Neoplasms; Methylnitronitrosoguanidine; Mice; Mice, Inbred C57BL; Mutation; Neoplasm Transplantation; Neoplasms, Experimental; Spleen; Transplantation, Isogeneic

Five gastric carcinomas, induced in inbred Wistar rats by oral administration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) dissolved in drinking water, were successfully transplanted to isologous rats. The transplants grew to a size of 10 to 35 mm in diameter within 8 to 25 weeks of implantation. In one case, serial transplantation were maintained up to the 11th generation, with occurrence of distant metastasis in the 3rd generation. Histological histochemical, and electron microscopical comparison of the original and transplanted tumors revealed that (1) the original tumors were quite well differentiated, forming either papillary or tubular structures, whereas the transplants were more anaplastic and pleomorphic showing often solid nests; and (2) tumor cells with gastrointestinal differentiation and cells with neuroendocrine differentiation were present and evenly distributed in both the original and the serially transplanted tumors. As it is unlikely that the normal and neoplastic neuroendocrine cells are growing side-by-side with and independently of the epithelial neoplastic components in the present series of transplants, the findings strongly suggest (1) the multidirectional potency of the inbred rat stomach carcinoma cells and (2) the common neoplastic origin of the epithelial and neuroendocrine components.

Topics: Animals; Carcinoma; Histocytochemistry; Lung Neoplasms; Male; Methylnitronitrosoguanidine; Neoplasm Metastasis; Neoplasm Transplantation; Neoplasms, Experimental; Rats; Stomach; Stomach Neoplasms; Transplantation, Isogeneic

Seven of 35 male Wistar rats developed well-differentiated adenocarcinoma of the glandular stomach on combined treatment with N-methyl-N'-nitro-N-nitro soguanidine and 4-nitroquinolin 1-oxide. One of the tumors was successfully transplanted into newborn Wistar rats by subcutaneous inoculation. The latent period after inoculation was less than one month and the growth of the transplanted tumor was slow throughout 10 transplant generations. The tumor appeared nodular or cystic in subcutaneous tissues of rats and often caused ulceration of the skin. The histology of transplanted tumors was very similar to that of the primary tumor. Metastasis to both lungs was observed in one rat of the first transplant generation.

Topics: 4-Nitroquinoline-1-oxide; Adenocarcinoma; Animals; Animals, Newborn; Lung Neoplasms; Male; Methylnitronitrosoguanidine; Neoplasm Metastasis; Neoplasm Transplantation; Neoplasms, Experimental; Rats; Stomach Neoplasms; Time Factors; Transplantation, Homologous

Topics: Adenocarcinoma; Animals; Dogs; Female; Lung Neoplasms; Lymphatic Metastasis; Male; Methylnitronitrosoguanidine; Neoplasm Metastasis; Neoplasms, Experimental; Nitrosoguanidines; Stomach Neoplasms