Experimental metastasis in nude mice of NIH 3T3 cells containing various ras genes.

Abstract

These studies have compared the ability of NIH 3T3 cells containing different ras oncogenes to form tumor nodules in the lungs of nude mice after tail vein injection. The genes studied include the normal cellular and bladder tumor ras genes, recombinant viral/cellular ras genes, recombinant yeast/mammalian ras genes, and a constructed gene with yeast RASI sequences significantly modified by deletions and an oncogenic mutation. The results show that NIH 3T3 cells containing these genes readily form lethal tumor nodules in the lungs of nude mice after tail vein injection. No control NIH 3T3 cells formed lung tumors within 66 days. Although there were some quantitative differences in the potencies of the various lines, the striking conclusion is that NIH 3T3 cells transformed by either normal or activated mammalian ras genes form approximately equal numbers ofexperimental lung metastases. In addition, cells transformed by a significantly modified yeast RAS] gene containing a purposefully introduced oncogenic mutation were also equally active in this assay. The amount of p21 (the 21-kDa protein encoded by ras), as measured by immunoprecipitation, was approximately the same in the parent lines before injection as in the tumors recovered after injection. This result indicates that there is no selection for metastatic sublines containing larger quantities of p21. Transfection of EJ bladder tumor ras DNA into NIH 3T3 cells followed by injection 3 days later into the tail veins of nude/beige mice indicated that the EJ ras gene can confer a metastatic phenotype within 3.5 cell generations without selection or clonal growth in vitro. Thus, the biochemical changes initiated after introduction of the c-Ha-ras gene into NIH 3T3 cells result in the almost immediate acquisition of phenotypes necessary for experimental metastasis.Invasion and metastasis have always been considered the hallmarks of malignant tumors in their most lethal form. The fully metastatic cell is differentiated from its normal counterparts by the acquisition of many new phenotypes, including the following abilities: to escape normal growth control; to break through host basement membranes; to invade and exit vessel walls; to survive in the circulation; to attract a blood supply (angiogenesis); to survive host immune attack; and, finally, to grow into discrete tumors at alternate sites. These phenotypes have been presumed to be acquired gradually by cells during the long processes ofpromotionAnd progression that occur after initiation (1-5). The formation of metastatic variants is thought to take place during a protracted time period of up to 20 or 30 years in humans and proportionately shorter periods in animals. All of this information has suggested that multiple genetic or epigenetic steps are required to complete the phenotypic changes necessary for cells to become metastatic. Activation of cellular oncogenes by various genetic and epigenetic mechanisms has been increasingly implicated as an important step in malignant transformation (6-8). Howe...

Transcription factors control invasion: AP-1 the first among equals

“…Activated Ras, Rac, Rho and Cdc42 in particular have long been recognized as regulators of tumor cell invasion (Hernandez-Alcoceba et al, 2000;Campbell and Der, 2004). Ras expressing NIH 3T3 cells are capable of inducing experimental metastasis in nude mice (Bradley et al, 1986). Similarly, invasion is enhanced in NIH 3T3 fibroblasts transformed by the oncogenes v-sis (PDGFR), v-erb-B (EGFR), v-mos, v-ras and v-fos (Melchiori et al, 1990).…”

Phenotype-assisted transcriptome analysis identifies FOXM1 downstream from Ras–MKK3–p38 to regulate in vitro cellular invasion

“…One common mutation in the Ha-Ras gene is the EJ mutation, which consists of substitution of valine for glycine in codon 12. Cells carrying this mutation colonize the lungs of athymic nude mice after tail vein injection (Bradley et al, 1986;Zhang and Schultz, 1992). Moreover, it has been demonstrated that both ERK1/2 and JNK are active in Ha-Ras EJ stably transfected NIH3T3 cells, but only ERK was required for an invasive phenotype (Janulis et al, 1999).…”

Prenylated C17orf37 Induces Filopodia Formation to Promote Cell Migration and Metastasis

“…NIH3T3 is a nontransformed cell line and does not form tumors or lung metastasis when injected into nude mice (40). However, stable overexpression of different oncogenes has been known to induce oncogenic transformation of NIH3T3 cells (40).…”