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The c-Ha-ras-1 locus in 84 cancer patients was examined for allelic restriction fragment length's polymorphism, as well as for distribution of four common c-Ha-ras-1 alleles (a1, a2, a3 and a4) in lung, ovarian and thyroid cancer patients. In approximately half (8 out of 15) lung and ovarian carcinomas possessing a4 allele, alterations in the Ha-ras locus (deletion, amplification and change in allele length) were detected, as compared to 2 cases of rearrangements out of 40 tumors lacking the a4 allele. An increased a4 allele frequency was found in individuals with lung and ovarian carcinomas, as compared to both controls--summarized literature data, and thyroid cancer patients. On the other hand, homozygosity for the a2 locus, resulting from deletion in another allele, and increased a2 allele frequency in thyroid cancer patients were observed. Thus, a4 and a2 alleles of the c-Ha-ras-1 may perhaps be viewed as genetic markers of predisposition to lung, ovarian and thyroid cancer, respectively, in combination with other clinical parameters.

Problems of the origin, structure and functions, in the cells and tissues, of the so-called proto-oncogenes (c-onc)--cell genes, homologues and oncogene foreparents (v-onc)--are considered in the review. Up-to-date data are given to show the participation of the main groups of proto-oncogenes in the processes of cell division, proliferation and differentiation. The role of c-onc genes is found to be important for fundamental manifestations of the cell life activity. Special attention is paid to the problem of interrelation of the proto-oncogenes with growth factors and their receptors.

A method of the restriction analysis by Msp I enzyme has been used to analyze the 12th codon of Ha-ras-1 protooncogene in 10 human carcinomas and in the stomach mucosa adjacent to them their 5 metastases into the regional lymph nodes and in 2 ulcers. No point mutation was found.

In metastases and malignant tumors arising from gastric mucous membrane irrespective of their localization the method of electrophoresis and enzyme-electroporesis in agar gel demonstrates the presence of rapidly moving anode fractions I, II, and III corresponding to pepsinogen-pepsin isoforms of normal gastric mucosa but lacking proteolytic activity.

Some fractions of low molecular weight (LMW) nuclear RNAs were shown to be present in the cytoplasm of rat liver cells. In addition to known 4S tRNA, 5S and 5,8S rRNAs U3 and 8S1 LMW nuclear RNAs, 8SII and 8SIII LMW RNAs have been detected in RNA preparations of free total and membrane-bound polysomes. The U3 and 8SI polysoma I RNAs seem to be associated with high molecular weight polysomal RNA. Using thermal phenol fractionation, that some LMW RNAs were shown to be slightly bound to the cellular structures whereas some others are bound more tightly. Considerable amounts of LMW RNAs are tightly bound to the chromosome-nucleolar apparatus. They can be extracted only at 85 degrees C. The data presented are discussed with regard to LMW nuclear and polysomal RNAs functions.

The fractional composition of serum lipoproteids in patients with malignant tumours and in noncancerous disorders as well as in healthy donors has been investigated to detect the cancer specificity of the appearance of the additional abnormal RNA-lipoprotein fraction. No distinct correlation is found between the presence of the additional serum lipoprotein fraction and human malignancy.

An attempt was made to correlate variations in the level of glycogen during chemically induced carcinogenesis (DENA) with changes in the activity of enzymes participating in biosynthesis of this polysaccharide (UDPG-glycosensynthetase, phosphoglucomutase, UDPG-pyrophosphorylase). It is found that in DENA action in the rat liver two phases may be sharply differentiated--initial (the 1st month) with marked alterations in the content of glycogen and the activity of related enzymes, and final one (4-6th month) which is characterized by reduction of glycogen content, a new sharp rise in the activity of phosphoglucomutase and UDPG-pyrophosphorylase, and somewhat decreased activity of UDPG-glycogensynthetase, as compared with the initial values.

The results of a comparative analysis of genes of Rous sarcoma virus (Prague C strain) and those of avian sarcoma virus D6 isolated from 9,10-dimethyl-1, 2-benzoanthracene-induced avian tumor are presented. The genes of both viruses were shown to be highly homologous.

Pepsinogen mRNA is shown to be the major fraction of rat poly (A)+RNA. It codes polypeptide with molecular weight of about 45 kD. Changes in the pepsinogen mRNA content at the early stage of carcinogenesis are nonspecific and are due to the toxic effect of MNNG. Steady shifts in the quantity of pepsinogen mRNA are found between the 1st and 3d months. Pepsinogen mRNA content decreases down to the half of the normal one between the 3d and 6th months. A quantity of RNA capable to be a template for pepsinogen synthesis is reduced by more than 90% in the MNNG induced tumour. The pepsinogen production defect in gastric mucosa neoplasia is mainly due to pepsinogen mRNA synthesis damage.

An attempt was made to elucidate the possible participation of low molecular weight nuclear RNAs in the transcription process. The parameters of the RNA synthesis cell-free system in isolated rat liver nuclei were studied for this purpose. Tissue homogenization in isotonic sucrose during isolation of the nuclei resulted in a loss of 4S nuclear RNA. The dependence of RNA synthesis on the salt concentration in the incubation medium is indicative of possible initiation of the RNA synthesis in this system. At salt concentration of 0.08 M 50-75% of incorporation is due to the activity of RNA polymerase II. Under these conditions the electrophoretically homogenous individual fractions of low molecular weight nuclear RNAs do not affect specifically the activity of RNA polymerase II. No evidence for the participation of low molecular weight nuclear RNAs in the mechanisms of heterogeneous nuclear RNA synthesis were obtained.

The messenger RNA of pepsinogen from gastric tumors was found to show a lowered activity in providing the synthesis of a specific protein of gastric mucosa--pepsinogen in the acellular system. A relative amount of free polysomes in human gastric tumors is increased compared with the mucous membrane of the stomach. The pepsinogen messenger RNA of human gastric mucosa stimulates efficiently the in vitro incorporation of labelled leucin into the protein and induces the pepsinogen-pepsin synthesis in the polysome system of human gastric mucosa and rat liver.

The results of investigations on total nucleic acids content and RNA turnover in the cells of tumor NK/Ly and of the spleen in tumor-bearing mice after single exposure to fast electrons are described. In every case the irradiation results in reliable changes of parameters under study. The pattern of changes in nucleic acids content and turnover in the spleen after the exposure to fast electrons is in a good agreement with the available data concerning the influence of x- and y-radiation. The irradiation action on nucleic acids content and turnover in ascites tumor NK/Ly cells is qualitatively and quantitatively similar to that in splenic cells.

Application of preparative electrophoresis in agarose gel for isolation of chromosomal and extrachromosomal genetic elements is described. The above-mentioned method is used for fractionation of chromosomal DNA according to the molecular weight; for isolation of the plasmid containing the insertion of the viral oncogene myc and for separation of the viral oncogene myc insertion from the vector (a linear form of plasmid pBR 322). The method can be successfully applied in molecular biology, microbiology and medicine.

A model of gastric tumour induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in rats made it possible to detect essential alterations of chromatin-DNA-protein complexes, that is a weakening of the DNA-protein linkage. The changes appear at early stages of carcinogenesis and persist in induced adenocarcinomas of the stomach. Simultaneously an inhibition was established in pepsinogen synthesis during MNNG carcinogenesis, which reflects a damage in expression of functionally important genetic information. This fact shows a molecular-genetic connection between the process of the gastric mucosa malignization and a disturbance of physiologically important tissue-specific gene functions.

Apart from heterogeneous high-molecular DNAs, two fractions corresponding to 17 and 20 MD of DNA and homogeneous with respect to mobility are to be found in preparations of nucleic acids of rat blood serum. The former fraction (17 Md) is greater than the latter in healthy animals. This ratio is reversed in the blood serum of rats with Zajdela's hepatoma. The relative predominance of 20 Md DNA is still more pronounced in ascitic liquid which washes tumor cells.

We have shown that 8S and U2 fractions of low molecular weight nuclear RNA lmwn RNA) have tow stable conformational states with different electrophoretic mobilities. We have shown also that fractions UIa and UIb are conformational isomers. Fractions 8S and U2 are present only in one conformational state during electrophoresis, while UI RNA is always represented by both conformations. The conformation of lmwn RNAs is dependent upon conditions of isolation of nuclei and of extraction of RNA. It may change during storage of water solution of RNA at -20 degrees. Conformational changes discovered are not the result of degradation. Only one of two stable conformations of any lmwn RNA may be physiologically active, as it is the case of 5S rRNA and tRNAS. One ought to keep this in mind while studying the functions of low molecular weight nuclear RNAs.

Low molecular weight nuclear RNAs (LMWN RNAs) isolated by thermal phenol fractionation from malignant tumor of the stomach and the mucous membrane of patients with gastric ulcer have been studied. There were found some differences in the relative content of U1 and U2 nucleoplasmic fractions as well as of loosely bound to a nucleolus U3 fraction of LMWN RNAs. The changes observed resemble those obtained earlier for experimental animal tumors.

Genomic DNA of intact colonic mucosa obtained from a female patient suffering colonic cancer revealed amplified nucleotide sequences (multiple copies) related to viral myc oncogene. The study failed to detect amplification in tumor. Causation and pathways of the event are discussed.

The structural proteins and the oncogene product of the avian sarcoma virus (ASV) D6 were analyzed by the radioimmunoprecipitation. ADV D6 was obtained from the chemically induced tumour. ASV D6 contains all the structural proteins found in RSV, but some of them (p19, gp 85) differ from those of RSV. The product of ASV D6 oncogene is pp65src. The protein kinase activity of this src protein is identical to that of wt pp60src. The nature of some other proteins, which can be phosphorylated in this reaction, is discussed.

The cell-free translation method has shown that pepsinogen mRNA is a predominant fraction in the total poly(A)+ RNA from human gastric mucosa. The pepsinogen protein with the molecular weight of 45 kDa has been identified. The level of pepsinogen mRNA decreased in tumours as compared with normal mucosa but in most cases pepsinogen mRNA synthesis depression was not total.

Cells of Ehrlich ascites carcinoma were incubated under aerobic and anaerobic conditions with 3H-uridine, and the amount and radioactivity of poly(A)-containing and poly(A)-non-containing fraction of cytoplasmatic RNA were determined. It is shown that RNA biosynthesis, as judged by the labeled precursor incorporation, is nearly similar to that under oxygen supply conditions. The specific radioactivity of poly(A)-containing fraction of cytoplasmatic RNA of cells incubated under anaerobic conditions was 2 times as much as that under aerobic ones.

The paper discusses changes occurring in the enzymatic activity of pepsin in rat's gastric mucosa at early stages of carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine treatment with drinking water. All doses (5, 15, 45, 75 and 150 mg/l) proved to be effective and inhibited pepsinogen biosynthesis considerably. Particularly sharp drops in the enzyme activity were observed with the concentrations of 45, 75 and 150 mg/l. The effect was reversible at early stages, particularly, at low concentrations of the agent. It is suggested that the critical point reached by pepsinogen synthesis in gastric mucosa carcinogenesis, which is manifested by the enzyme synthesis resumption on treatment being suspended, may be regarded as the check point in the course of neoplastic development.

An attempt was made to elucidate possible participation of low molecular weight nuclear RNA's (LMWN RNA's) in the transcription process. For this purpose, we studied the effect of individual fractions of LMWN RNA's, isolated by polyacrylamide gel electrophoresis, on the endogenous RNA synthesis in isolated nuclei. We have found no influence of LMWN RNA's on the incorporation of labeled precursors in the acid-insoluble material under the conditions when RNA polymerase I is predominantly active. The results obtained thus indicate that LMWN RNA's do not participate in the regulation of 45S pre-rRNA synthesis and they do not belong to limiting factors in pre-rRNA synthesis.

The obtained specific antiserum against the 1st isoform of pepsinogen of human gastric mucosa responds in immunodiffusion only to the 1st pepsinogen isoform but not to the IId and IIIth one. Human pepsinogen has no common antigenic determinant with pig pepsinogen. The methods of electrophoresis and immunodiffusion reveal the Ist, IId and IIIth isoforms of pepsinogen in human gastric tumors and their metastases, however, they do fail to show any enzymic activity.

Low molecular weight nuclear RNAs (LMWN RNAs) from rat liver, Zajdela hepatoma and rat hepatoma induced by DENA have been studied. The changes in the relative content of nucleoplasmic U1 and U2 RNAs, nucleolus U3 RNA and chromatine 5S RNA have been discovered in both hepatomas. Whereas 8S1 and U3 RNA were found in polysomes from rat liver but not in those from Zajdela hepatoma.

Ha-ras restriction fragments' length polymorphism (RFLP) in white blood cells and stomach tissues from patients with carcinoma and ulcer of the stomach was examined. Genomic DNAs were digested with Xho I, Pvu II, Pst I, Msp I, Bcn I, Mva I, Bsp RI. No Ha-ras-1 polymorphic variants specifically associated with the cancer disease were detected. RFLP of the 3'-noncoding sequence of c-Ha-ras-1 gene had got features of the definite human population. The cells forming the tissue were examined and individual peculiarity of the methylated residues disposition seemed to influence RFLP of the 5'-noncoding sequence of c-Ha-ras-1.

The authors report the results of separate determination of the concentration of free adenine nucleotides (ATP, ADP, AMP) in tumors, intact animals liver, and tumor-bearing animals liver. In Zajdela ascites hepatoma, ascites tumor NKly and solid lymphosarcoma, solid hepatomas 46 and 22 A the amount of ATP and ADP was found to be markedly reduced compared with their content in the liver. The ratio ATP/ADP is increased in ascites cells of tumor NKly, Zaidela hepatoma and lymphosarcoma and is decreased in solid hepatoma 46 and 22 A. Cell energy potential, calculated on the basis of ATP ratio to a sum of adenine-nucleotides, is also increased in ascites cells of tumor NKly, Zaidela hepatoma and is diminished or remains unchanged in hepatoma 46 or 22A. Cell energy charge is increased in tumor NKly, Zajdela hepatoma, lymphosarcoma and is decreased in solid hepatoma 46 and 22A.

The problem of cellular protooncogene activation is considered. This stage during carcinogenesis is evaluated as critical in the whole process of neoplasia development. Four possible principal pathways of protooncogene activation are discussed: oncogene amplification; chromosomal translocations; insertions and transpositions of genetic material; point mutations. Two ideas in carcinogenesis based on the oncogene conception have attracted special attention: the "dose hypothesis" emphasizing the importance of the quantitative changes of oncoproteins and the idea of the qualitative alterations of protooncogenes.

A study was made of the distribution of pepsinogen-synthesizing polyribosomes in the rat's stomach mucous membrane, in the process of chemical carcinogenesis induced by N-methyl-N'-nitro-N-nitrozoguanidine. A sharp decrease in the content and proteolytic activity of pepsin is shown in cytosol and membrane-bound polyribosomes of the mucous membrane of the rat stomach due to the inducing substance. The appearance of this enzymatic activity is noted in free polyribosomes isolated from the rat stomach tumours.

State and prospects of the drug cancer therapy are examined in the light of achievements of modern molecular oncology. Special attention is paid to the molecular genetic analysis of the appearance of individual and multiple cellular drug resistance in connection with amplification of definite genes as well as oncogenes. The idea about the possible role of oncogene activation as a universal cell reaction in response to an injury of environmental factors is advanced. It concerns both oncogenesis and induction of cancer cell drug resistance.

The standard analytical and preparative electrophoresis in polyacrylamide gel did not reveal qualitative differences in the fraction composition of c-RNA of the ascitic tumour cells (Zaidel hepatoma, Ehrlich carcinoma, NK/ly lymphoma) and normal liver cells. In vitro the tumour and normal cells efficiently incorporated the labeled uridine into the all main classes of c-RNA (4S, 18S, 28S, fractions above 28S), the process being more intensive in the tumour cells. The presence of tumours in the animal organism had a significant effect on RNA biosynthesis in the liver, the effect being dependent on the tumor nature. Lucantone (miracyl D) had practically no effect in vitro on the quantitative content of the summation c-RNA and its fractions in all cells studied. However, it markedly inhibited the metabolism of the main fractions of c-RNA in the cells of Zaidel hepatoma and Ehrlich carcinoma. The effect of lucatone in the cells of NK/ly lymphoma was contrary.

Low molecular weight nuclear RNAs (LMWN RNAs) of normal and neoplastic tissues: the rat liver and Zajdela hepatoma, mouse spleen and NK/Ly ascites tumor, as well as the cultures of normal chick embryo fibroblasts and of those transformed with Rous sarcoma virus were studied by electrophoresis in 8% and 15% polyacrylamide gels. As a result of the study no qualitative differences, i.e. differences in the number of LMWN RNA main fractions and their electrophoretic mobility were found. But there were revealed quantitative variations in the relative amount of definite fractions of these RNAs. An increase of the U3 RNA content in ascites tumors may be connected with an enhancement of the ribosomal RNA synthesis. Variations in the content of low molecular weight RNAs in oncogenic virus transformed cells may reflect an excessive synthesis of low molecular weight viral RNAs during the process of virus reproduction. The quantitative alterations observed seem to be of special value since LMWN RNAs are likely to perform regulatory functions.