Expression of ras and metastatic behavior in panel of cell lines derived from infection of NIH 3T3 cells with Kirsten murine sarcoma virus (original) (raw)
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Complex effects of Ras proto-oncogenes in tumorigenesis
Carcinogenesis, 2003
Ras proteins have been found mutated in about one-third of human tumors. In vitro, Ras has been shown to regulate distinct and contradictory effects, such as cellular proliferation and apoptosis. Nonetheless, the effects that the wild-type protein elicits in tumorigenesis are poorly understood. Depending on the type of tissue, Ras protooncogenes appear to either promote or inhibit the tumor phenotype. In this report, we treated wild-type and N-ras knockout mice with 3-methylcholanthrene (MCA) to induce fibrosarcomas and found that MCA is more carcinogenic in wild-type mice than in knockout mice. After injecting different doses of a tumorigenic cell line, the wild-type mice exhibited a shorter latency of tumor development than the knockouts, indicating that there are N-ras-dependent differences in the stromal cells. Likewise, we have analyzed B-cell lymphomas induced by either N-methylnitrosourea or by the N-ras oncogene in mice that over-express the N-ras proto-oncogene and found that the over-expression of wild-type N-ras is able to increase the incidence of these lymphomas. Considered together, our results indicate that Ras proto-oncogenes can enhance or inhibit the malignant phenotype in vivo in different systems.
Mechanism of activation of an N-ras oncogene of SW-1271 human lung carcinoma cells
Proceedings of the National Academy of Sciences, 1984
An N-ras-related transforming gene was detected in the human lung carcinoma cell line SW-1271 and molecularly cloned. The lesion responsible for its acquisition of transforming activity was localized to a single nucleotide transition from A to G in codon 61 of the predicted protein. This lesion in the second exon results in the substitution of arginine for glutamine at this position. These findings, together with previous studies, indicate that the activation of ras oncogenes in human tumors is most commonly due to point mutations at one of two major "hot spots" in the ras coding sequence.
The role of the RAS oncogene in the formation of tumours
Journal of Cell Science, 1988
A c-Ha-ras 1 oncogene, cloned from the EJ human bladder carcinoma cell line, was inserted into a shuttle vector carrying the selectable marker gene gpt that encodes the enzyme xanthine-guanine phosphoribosyl transferase. This construct, pSV2gptEJ, was transfected into NIH 3T3 cells by the calcium phosphate precipitation method and cells that had incorporated the plasmid were selected by growth in the presence of mycophenolic acid to which gpt confers resistance. A number of transfectant clones were tested for tumorigenicity by inoculation into nude mice. The take incidence was variable and the tumours arose only after a prolonged latent period. Many inocula produced no tumours. These results were consistent with the view that the tumours arose by selective overgrowth of minority cell populations. Cell lines were derived by explantation of these tumours and were back-selected in 2-thioxanthine, a cytotoxic analogue of the xanthine-guanine phosphoribosyl transferase substrate. Five cl...
Detection of ras oncogenes by analysis of p21 proteins in human tumor cell lines
Urological Research, 1988
To detect mutationally activated ms oncogenes, we analyzed electrophoretic mobilities of ras p21 proteins utilizing the fact that many ms oncogenes produce abnormal p21 proteins that migrate at SDS/polyacrylamide gel electrophoresis as a fast-moving or slow-moving species in comparison to a normal p21 depending on the kind of mutation. Of 18 human tumor cell lines analyzed, four (SW480, SW620 and SW403 colon cancers, and SW626 ovary cancer) produced p21 belonging to the slow-moving species, suggesting a point mutation within codon 12 of a member of the three ms genes, H-, Ki-and N-ms. Subsequent DNA transfection analysis using NIH/3T3 cells as recipients identified activated Ki-ras oncogenes in the same four but not in other 14 cell lines. Thus, the analysis of p21 might serve as a rapid primary method to screen a large number of tumor materials for the presence of certain types of mutationally activated ras oncogenes.
Early Cellular Responses to the Activation of a Mitogenic/Oncogenic Viral K-RAS Protein
Annals of the New York Academy of Sciences, 1988
GTP-binding RAS proteins, ranging in size from 21 kDa to 40 kDa, have been found in all eukaryotes from budding yeast and slime molds to mammalian Normal cellular RAS proteins participate in driving normal mammalian cells through the cell cycle by operating specifically during the later stages of the GI phase"' and perhaps during the G , phase." Unlike cellular RAS proteins, which promote but cannot initiate cell cycle transit, "activated" oncogenic forms of the RAS proteins are able to initiate and then promote transit through the cell cycle. Thus, microinjecting the oncogenic T24H-RAS protein from the EJ human bladder carcinoma into quiescent NIH 3T3, N R K or REF-2 cells stimulates them to transit the C , phase and initiate DNA replication." Also, as we shall see, the oncogenic K-RAS protein of Kirsten sarcoma virus stimulates quiescent tsKSV-NRK cells to proliferate in the absence of exogenous growth factors.12 Point-mutated ras genes and their oncogenic RAS protein products have been found in a substantial proportion of human tumors and therefore have been implicated in the development of human cancer." Clearly finding out how "activated" RAS proteins start quiescent cells cycling should contribute substantially to our understanding of the origins of some human neoplasms. Membrane-associated RAS proteins appear to influence the transduction of receptor signals by modulating the activation of membrane-associated signaling enzymes such as adenylate cyclase and phosphoinositidase C.'"'' The signal given by the binding of a growth factor, such as PDGF, to its receptor displayed on the cell surface is transduced by a sequence of events which is only now beginning to be understood (SCHEME 1). In many cases, the binding of a growth factor to the extracellular domain of the receptor causes the rapid phosphorylation of the receptor's cytoplasmic domain at a tyrosine residue.'' It is generally believed that receptor tyrosine phosphorylation triggers the events leading to DNA replication by a mechanism which involves increased hydrolysis of phosphatidylinositol 4,5-bisphosphate 186 DURKIN er al.: MITOGENIC/ONCOGENIC K-RAS PROTEIN 187 Mitogens Mitogens SCHEME 1. A simplified view of the transduction of a mitogenic signal from receptors displayed on the cell surface to early-acting proliferogenic genes. DAG, diacylglycerols; IP3, inositol 1,4,5-trisphosphate; IP,, inositol 1,3,4,5-tetrakisphosphate. The primary PIP, degradation products, inositol 1,4,5-trisphosphate (IP,) and diacylglycerols (DAG), profoundly affect the cell. IP, triggers the release of Ca2+ from the endoplasmic reticulum and its phosphorylated derivative inositol 1,3,4,5tetrakisphosphate (IP,) opens membrane CaZ+ channel^.^*-^^ The intracellular Ca2+ surge, which is a characteristic feature of most, if not all, mitogenic signals, is capable of stimulating many different cellular activities. It is the established view that the DAG's produced by PIP2 hydrolysis collaborate with the CaZ+ surge to translocate protein kinase C (PKC) from the cytosol to the plasma membrane, where it is activated. Once associated with membrane, PKC phosphorylates as yet undefined substrates which are important for a number of cellular processes including proliferati or^.'^.'^ A clue to why "activated" RAS proteins are oncogenic may rest in how they stimulate quiescent cells to proliferate, even in the total absence of exogenous growth factors. Do they directly or indirectly generate Ca2+ and membrane-associated PKC signals like mitogenic growth factors22-"? Indeed, there is some indirect evidence that they do,2628 but here we present the first direct demonstration that one of these proteins, a temperature-sensitive variant of the viral K-RAS protein, does trigger a cytosolic Ca2+ transient and a brief surge of membrane-associated PKC activity. MATERIALS AND METHODS Cell Quiescence and Stimulation Uninfected NRK cells and tsKSV-NRK cells were the gift of M. Scolnick (Merck Sharpe and Dohme, West Point, PA). The tsKSV-NRK cell line was produced by
Blood, 1990
DNA from 161 patients with various forms of hematologic malignancies were investigated for mutations in exons 1 and 2 of the N-RAS. K-RAS and Ha-RAS gene by direct sequencing of DNA amplified in vitro by the polymerase chain reaction. Mutations involving either codons 11,12, or 13 of the N-RAS gene were identified in 18 of the 161 patients. The relative frequencies of N-RAS gene mutations in these hematologic disorders was as follows: acute myelogenous leukemia (AML), 25%; acute lymphoblastic leukemia (ALL), 14%; myelodysplastic syndromes, 24%; and myeloid and lymphoid blast crisis of chronic myelogenous leukemia (CML), 3%. No correlation was observed between the presence of mutations and cytologic features or immunophenotype of these malignancies. Mutations
Proceedings of the National Academy of Sciences, 1997
The gene-mutation-cancer hypothesis holds that mutated cellular protooncogenes, such as point-mutated proto-ras, ''play a dominant part in cancer,'' because they are sufficient to transform transfected mouse cell lines in vitro [Alberts, B., Bray, D., Lewis, J., Raff, M., Roberts, K. & Watson, J. D. (1994) Molecular Biology of the Cell (Garland, New York)].
Molecular genetics and cellular events of K-Ras-driven tumorigenesis
Oncogene, 2018
Cellular transformation and the accumulation of genomic instability are the two key events required for tumorigenesis. K-Ras (Kirsten-rat sarcoma viral oncogene homolog) is a prominent oncogene that has been proven to drive tumorigenesis. K-Ras also modulates numerous genetic regulatory mechanisms and forms a large tumorigenesis network. In this review, we track the genetic aspects of K-Ras signaling networks and assemble the sequence of cellular events that constitute the tumorigenesis process, such as regulation of K-Ras expression (which is influenced by miRNA, small nucleolar RNA and lncRNA), activation of K-Ras (mutations), generation of reactive oxygen species (ROS), induction of DNA damage and apoptosis, induction of DNA damage repair pathways and ROS detoxification systems, cellular transformation after apoptosis by the blebbishield emergency program and the accumulation of genomic/chromosomal instability that leads to tumorigenesis.