Expression of the metastatic phenotype in cells transfected with human metastatic tumor DNA.

Abstract

reported experiments in which we were able to transfer the phenotype of tumor metastasis via transfection of DNA extracted from a human metastatic cervical adenocarcinoma. This DNA induced the conversion of recipient tumorigenic cells from a nonmetastatic to a metastatic phenotype. Moreover, we associated this change with the transfer of a specific human DNA fragment. In the intervening time, we have tried to extend and solidify these results. These conversions to a metastatic phenotype were reproduced on some occasions but not on others. As we have reported at a number of scientific meetings, the initial reported linkage to a specific DNA fragment was incorrect, and we were unable to establish a linkage with another human DNA fragment. After 3 years of continuous efforts to clarify these initial observations, we must now conclude that they do not represent a reproducible biological phenomenon. Our reported observations on the association of the ras oncogene with the metastatic phenotype remain highly reproducible in our laboratory and others. We hope that experiments of this sort will eventually lead us and others to successfully identify genetic determinants of metastasis.

The nucleotide binding motif of hepatitis C virus NS4B can mediate cellular transformation and tumor formation without Ha-ras co-transfection

“…These plasmids were then used in a standard transfection assay, essentially as described. 9,12,[15][16][17] As shown in Fig. 1A and B, a large number of colonies were detected in cells transfected with NS4B, Ha-ras, or both.…”

“…A standard transfection assay was performed essentially as previously described. 9,12,[15][16][17] Single stock NIH 3T3 cells were plated in 6-well plates (2.5 ϫ 10 5 cells per well), grown for 24 hours, and then transfected with 0.5 g of the pcDNA3.1-NS4B plasmid (wild-type or mutant versions), 0.5 g pEJ6.6, or both, using Lipofectamine 2000 (Invitrogen, Carlsbad, CA). Empty pcDNA3.1 plasmid was co-transfected with pEJ6.6 samples as a source for neomycin resistance.…”

Isolation and preliminary characterisation of cDNA clones representing mRNAs associated with tumour progression and metastasis in colorectal cancer

“…Thus, although much has been learned of the role of oncogenes in the process of transformation, their role in metastasis is not clear, and it is likely that other, as yet uncharacterised sequences (e.g. Bernstein & Weinberg, 1985), may be related to the events associated with the activation of oncogenes and other genes during the metastatic process. In this regard pLM59 appears to represent a hitherto unknown gene (no homologous sequence was found in the Genbank sequence data bank) whose expression is at least correlated with the process of metastasis in colorectal cancer.…”

Generation of metastatic variants by transfection of a rat non-metastatic epithelial cell line with genomic DNA from rat prostatic carcinoma cells

“…However, oncogenes that transform NIH 3T3 fibroblasts and produce fibrosarcomas (Land et al, 1983) do not produce metastases when transfected into rat benign epithelial cells (Davies et al, 1993). Earlier work on the generation of metastatic variants of Rama 37 cells by transfection of genomic DNA from rat and human breast carcinoma cells confirmed the validity of DNA transfection as a technique with which to assay the metastatic capability of genomic British Journal of Cancer (1998) 77(2), 287-296 DNA fragments (Jamieson et al, 1990a;Davies et al, 1994), as well as that of a variety of cellular oncogenes (Bernstein and Weinberg, 1988), and the gene for calcium-binding protein p9Ka (Jamieson et al, 1990b;Davies et al, 1993). Using this technique, several DNA fragments closely associated with metastasis in human breast cancer cell lines have been identified (Chen et al, 1997).…”