Transformation of Human Bronchial Epithelial Cells Transfected by Harvey ras Oncogene

Abstract

Transfection of normal human bronchial epithelial (NHBE) cells with a plasmid carrying the ras oncogene of Harvey murine sarcoma virus (v-Ha ras) changed the growth requirements, terminal differentiation, and tumorigenicity of the recipient cells. One of the cell lines isolated after transfection (TBE-1) was studied extensively and shown to contain v-Ha ras DNA. Total cellular RNA from TBE-1 cells hybridized to v-Ha ras structural gene fragment probes five to eight times more than RNA from parental NHBE cells. The TBE-1 cells expressed phosphorylated v-Ha ras polypeptide p21, showed a reduced requirement for growth-factor supplements, and became aneuploid as an early cellular response to v-Ha ras expression. As the transfectants acquire an indefinite life-span and anchorage independence they became transplantable tumor cells and showed many phenotypic changes suggesting a pleiotropic mechanism for the role of Ha ras in human carcinogenesis.

Characterisation of human thyroid epithelial cells immortalised in vitro by simian virus 40 DNA transfection

“…Recently infection with a retrovirus carrying the adenovirus EIA gene has been used to generate a human thyroid cell line (Cone et al, 1988). Very few reports exist of successful transformation of human epithelium by ras oncogenes (Yoakum et al, 1985;Boukamp et al, 1986) and even in these cases the transformation appears not to be a direct effect of the ras oncogene introduced (Yoakum et al, 1985).…”

Evidence for alternative candidate genes near RB1 involved in clonal expansion of in situ urothelial neoplasia

“…[28][29][30] The successful creation of human tumor cells in vitro typically requires the use of chemical and physical agents or an entire viral genome to achieve immortalization, a prerequisite for subsequent transforming effects of cooperating oncogenes. [31][32][33][34] More recently, human epithelial and fibroblast cells were transformed in vitro by ectopic expression of telomerase catalytic subunit (hTERT) in combination with two oncogenes (the Simian virus 40 large-T oncoprotein and an oncogenic allele of H-ras). 35,36 Figure 6 Integration of deletion patterns identified in the 13q14 region with RB1 sequencing data and RB1 protein expression patterns.…”

Control of growth and squamous differentiation in normal human bronchial epithelial cells by chemical and biological modifiers and transferred genes.

“…TBE-1 and TBE-1SA were injected into nude mice and caused tumors with a latency of 7 to 12 and 2 months, respectively. The progression of TBE-1SA in malignancy occurred concurrently with development of progressively abnormal karyotypes including aneuploidy, gaps, breaks, and exchanges (19), suggesting that v-Ha-ras may cause chromosomal abnormalities that lead to secondary alteration of other loci. However, increased expression of other oncogenes, i.e., Ha-ras, Nmyc, c-myc, and c-raf, was not detected.…”

“…The initial study was performed with v-Ha-ras (plasmid H1) using a protoplast fusion technique (19). Under the selective pressure of 2% serum and maintenance of the cultures at confluency, four cellular foci appeared.…”

“…Activated proto-oncogenes that have been associated with lung cancer include the ras, myc, ard raf families (14)(15)(16)(17)(18), and transfected oncogenes have been shown to transform normal human epithelial cells (19). Very recently, we have isolated a SV40 T-antigen containing bronchial epithelial cell culture that has an indefinite lifespan (20) but retains the ability to respond to certain inducers of squamous differentiation (21).…”