High expression of shMDG1 gene is associated with low metastatic potential of tumor cells.

Metastasis is the primary cause of mortality associated with cancer. Molecular mechanisms leading to metastatic spread are poorly studied. To get a better understanding of this process, we compared the gene expression pattern of two isogenic cell lines, HET-SR and HET-SR1 (Rous Sarcoma Virus-transformed embryo hamster fibroblasts) with different metastatic activity using the differential display technique.

Efficient DNA binding by optically Pure Ruthenium Tris(bipyridyl) complexes incorporating carboxylic functionalities. Solution and structural analysis.

Herein, we report on the binding of optically pure ruthenium complexes Delta- or Lambda-[Ru(bpy)(2)(L-L)][PF(6)](2) [L-L = Hcmbpy = 4-carboxy-4'-methyl-2,2'-bipyridine (1), L-L = H(2)dcbpy = 4,4'-dicarboxy-2,2'-bipyridine (2)] to DNA. The binding constants of the two enantiomeric Delta-1 and Lambda-1 complexes to DNA were estimated from titration monitored by (1)H NMR spectroscopy. 2D transferred NOESY (TRNOESY) experiments support the conclusion that Delta-1 and Lambda-1 bind to DNA and that an intermediate-to-fast exchange occurs between bound and free Ru(II) complex.

The small G-protein RalA stimulates metastasis of transformed cells.

RAS oncogenes play a critical role in oncogenic transformation and metastases formation. Here we show that Ha-ras greatly stimulates spontaneous metastatic activity of transformed cells through the Ras/RalGDS/RalA intracellular signaling pathway. Introduction of RalA alone leads to a drastic increase of metastatic activity of transformed cells.

Molecular follow-up of preneoplastic lesions in bronchial epithelium of former Chernobyl clean-up workers.

Ionizing radiation is a potent lung carcinogen, but the precise molecular damage associated with it is still unknown. In this study we investigated cancer-related molecular abnormalities including K-ras (codon 12) mutation, p16(INK4A) promoter hypermethylation and microsatellite alterations at seven chromosomal regions in successive biopsies obtained from former Chernobyl cleanup workers in comparison with smokers and nonsmokers who have never had radiation exposure. Our results indicate that prolonged persistence of inhaled radioactive particles is associated with appearance of allelic loss at 3p12, 3p14.

A novel group IIA phospholipase A2 interacts with v-Src oncoprotein from RSV-transformed hamster cells.

We have isolated a novel isoform of phospholipase A(2). This enzyme was designated srPLA(2) because it was discovered while analyzing the proteins interacting with different forms of the v-Src oncoproteins isolated from Rous sarcoma virus-transformed hamster cells. It contains all the functional regions of the PLA(2) group IIA proteins but differs at its C-terminal end where there is an additional stretch of 8 amino acids.

Two consistently deleted regions within chromosome 1p32-pter in human non-small cell lung cancer.

Allelic losses at 1p32-pter have been reported as frequent events in human non-small cell lung cancer (NSCLC). To further characterize the region of deletions, we studied loss of heterozygosity on a panel of 102 microdissected NSCLC samples with 20 polymorphic markers spanning 1p32-pter. Two shortest regions of the overlap of the deletions (SROs) were found: SRO 2a (D1S417--D1S57) and SRO 2b (D1S450--D1S243).

Kinases of the Src family: structure and functions.

Tyrosine kinases of the Src family are involved in different signal transduction pathways in cells. The corresponding genes participate in such vital processes as growth, differentiation, adhesion, transcription, etc. Specific structural changes confer oncogenic properties to the Src protein.

Somatic genetic alterations (LOH) in benign, borderline and invasive ovarian tumours: intratumoral molecular heterogeneity.

Loss of heterozygosity (LOH) affects a number of chromosome regions in ovarian cancer, pointing to the possible involvement of tumour-suppressor genes in ovarian tumorigenesis. We performed comparative analysis of allelic loss at 6 frequently affected chromosome regions in a panel of 53 benign, borderline and malignant ovarian tumours. Precursor lesions could provide evidence that an accumulation of genetic events is required for normal ovarian epithelium to generate malignant tumours.

Phosphorylation of p125FAK and paxillin focal adhesion proteins in src-transformed cells with different metastatic capacity.

Hamster fibroblasts transformed by Rous sarcoma virus (RSV) display different metastatic potentials that are associated with specific structural features of the v-src oncoprotein. This diverse metastatic activity could be due to various tyrosine phosphorylation levels of specific src protein substrates. To check this hypothesis, phosphorylation of the FAK and paxillin proteins, involved in signal transduction pathways and known as src protein substrates, was tested.

Allelic imbalance and instability of microsatellite loci on chromosome 1p in human non-small-cell lung cancer.

The mapping of allelic loss on the short arm of chromosome 1 has been performed in non-small-cell lung cancer. We used a set of 11 microsatellite loci spanning 1p to examine the frequency of allelic imbalance in a panel of 58 tumours. Fifty-one of 58 (87.

C-terminal end of v-src protein interacts with peptide coded by gadd7/adapt15-like RNA in two-hybrid system.

The significant differences in the metastatic properties of hamster fibroblasts transformed by the Rous sarcoma virus (RSV) were associated with mutations in the v-src carboxy-terminal region. To identify the capacity of this region for protein-protein interaction the two-hybrid system was used. The cDNA clone (vseap1), producing the protein specifically bound with the v-src C-terminal part in yeast cells in vivo and in GST-fusion system in vitro was isolated.

Simultaneous detection of genetic and immunological markers in non-small cell lung cancer: prediction of metastatic potential of tumor.

The restriction fragment length polymorphism of c-Ha-ras-1 and L-myc genes and expression of cell surface effector molecules were studied to determine their potential utility as markers for assessing risk of metastasis in 84 lung cancer patients. We performed a comparative study of primary lung carcinomas, metastases, adjacent tissues and blood samples in a group of patients with lung cancer of different histological types, grade of differentiation and presence of regional and distant metastasis. No differences in the frequency of c-Ha-ras-1 rare alleles were found between lung cancer patients and unaffected controls.

Mechanisms of unusually high antioxidant activity of RSV-SR-transformed cells and of its suppression by activated p21ras.

We have previously demonstrated that hamster embryo fibroblasts (HEFs) transformed by Rous Sarcoma virus, Schmidt-Ruppin strain (RSV-SR) are highly resistant to damage by H202 (H2O2R), (in contrast to HEFs transformed spontaneously, or by bovine adenovirus and SV40), while N-ras transfection of RSV-SR transformants leads to suppression of pp6Ov-scr and of H2O2R. In this study we have examined (1) mechanisms of antioxidant activity (AOA) of HEFs transformed by these agents and (2) the possible role of the v-src gene in unusually high AOA of RSV-SR transformants and of activated ras oncogenes in its suppression. All transformants exhibit increased catalase and glutathione peroxidase (GP) activities, while SOD, glutathione and glutathione reductase (GR) were reduced.

Two novel variants of the v-src oncogene isolated from low and high metastatic RSV-transformed hamster cells.

Four different transformed cell lines were isolated as a result of independent infection of primary hamster fibroblasts by Rous sarcoma virus (RSV SR-D stocks). These lines differ by the level of their spontaneous metastatic activity: HET-SR-1, HET-SR-8, and HET-SR-10 cell lines induced 70-200 metastatic nodules in the lung and/or lymph nodes of inoculated animals (high metastatic lines, HM). Metastatic activity was not identified after injection of HET-SR cells (low metastatic line, LM).

Modulation of pp60v-src and pp60c-src expression in Rous sarcoma virus-transformed hamster fibroblasts transfected with activated N-ras.

Three phenotypically different hamster cell lines transformed with Rous sarcoma virus (RSV) were transfected with plasmid DNA containing an activated N-ras oncogene, and nine clones expressing various levels of p21N-ras were characterized. We examined the effects of p21N-ras on expression and kinase activity of resident src proteins by using a variety of assays that allowed us to discriminate between viral and cellular src proteins. In eight clones with a 10- to 20-fold increase in p21N-ras levels relative to the endogenous protein, we observed a marked reduction in the synthesis and kinase activity of p60v-src.

C-ets-1 protooncogene expression alters the growth properties of immortalized rat fibroblasts.

Ets family genes have been cloned and characterized from a variety of species ranging from human to Drosophila. The ets proteins encode transcription factors that activate transcription via specific binding to GGAA core sequence present in various promoter/enhancers. To investigate the role of ets protooncogene expression on the growth properties of rat embryo fibroblasts (REF), we constructed and introduced ets expression vectors into primary, as well as immortalized REF cells.

Clustering of discrete cell properties essential for tumorigenicity and metastasis. III. Dissociation of the properties in N-ras-transfected RSV-SR-transformed cells.

We have previously shown that RSV-SR-transformed hamster cells acquire high resistance to H2O2, i.e. the cytotoxic product of activated macrophages (H2O2R) and that they begin to secrete PGE (PGES), thus inactivating the CTA of NK cells.

BrdU-induced changes in the provirus of PR-RSV in mammalian cells.

Previously we demonstrated differences in the organization and methylation pattern of integrated Rous sarcoma proviral sequences in helper-dependent virogenic rat TWERC cells. In the present study we attempted to induce changes in the integrated viral genome of TWERC cells using 5-bromodeoxyuridine (BrdU). Four clones (A, B, C, and F) derived from the parental cell line were treated for 10 months with different concentrations of BrdU.

Unstable visible mutations induced in Drosophila melanogaster by injections of oncogenic virus DNA into the polar plasm of early embryos.

When RSV DNA cloned in pBR 322 or DNA of simian adenovirus Sa7 (C8) is injected into the pole plasm of embryos of various Drosophila stocks, the progeny of 1-70% of the surviving flies display visible mutations. The mutagenesis is partially directed: the loci mutating due to retrovirus and adenovirus DNA do not overlap. The majority of resulting mutants are characterised by high instability: reversions and new mutations occur in them, which sometimes spread over the whole population ("explosive" instability).

Differential expression of cellular genes in Rauscher leukaemia.

The methods of hybridization in solution and blot hybridization showed that spleen cells from BALB/c mice contain "silent" genes which can amplify and change their structure after infection by Rauscher leukaemia virus. The "silent" gene product is nuclear 35S RNA detectable by comparative electrophoretic analysis of the heterogeneous nuclear RNA from leukaemic and normal cells. About 7% of this 35S RNA is represented by the virus-specific sequences, but a major part is represented by the cellular sequences.

Oncogene expression in human tumors.

The expression of 9 oncogenes in primary tumors and in human tumors passaged in nude mice was tested: a total of 28 tumor types was analyzed. Oncogenes src, fps, and mos were not expressed in any of the tumors tested but oncogene myc was transcribed in most of the tumors and myc was over-expressed in 3 tumors passaged in nude mice (Ewing sarcoma, large intestine carcinoma and kidney carcinoma) and in primary fibrous histiocytoma. Enhanced transcription of ras and fos genes was observed nonspecifically in different tumors.

Detection of virus-specific sequences in Drosophila melanogaster mutants induced by injection of RSV DNA into early embryos.

The injection of purified Rous sarcoma virus (RSV) (Prague strain) into Drosophila melanogaster (Oregon R line) eggs changes the fly phenotype in certain cases, and RSV-specific sequences can be identified in the Drosophila genome (ref. 1 and preceding paper). Here we have used Southern blotting to analyse in greater detail the proviral DNA present in several mutant lines of D.