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| Prolonged culture of telomerase-immortalized human fibroblasts leads to a premalignant phenotype |
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| Author(s): Milyavsky M, Shats I, Erez N, Tang XH, Senderovich S, Meerson A, Tabach Y, Goldfinger N, Ginsberg D, Harris CC, Rotter V |
| Source: CANCER RESEARCH Volume: 63 Issue: 21 Pages: 7147-7157 Published: NOV 1 2003 |
| Times Cited: 64 References: 79 |
| Abstract: Telomere shortening in primary human fibroblasts results in replicative senescence, which can be overcome by telomerase (hTERT) overexpression. However, because immortalization is one of the hallmarks of malignant transformation, careful analysis of hTERT-immortalized cells is of crucial importance for understanding both processes. To this end, we infected WI-38 fibroblasts with a retrovirus carrying the hTERT cDNA and analyzed their proliferative behavior during 600 days [similar to500 population doublings (PDLs)] of continuous culture. Growth of three independent mass cultures was uniform for similar to150 PDLs after telomerase infection, followed by a progressive acceleration of growth in two of three cultures. Expression of p16(INK4A) was significantly elevated in the immortalized cells but gradually disappeared during the accelerated growth phase. This alteration correlated with loss of the contact inhibition response and conferred the cells with sensitivity to H-Ras-induced transformation. In contrast, the p53- and pRb-mediated checkpoints such as the DNA damage response, chromosomal stability and entry into quiescence remained intact, irrespective of INK4A locus expression. Importantly, detailed examination of one of the WI-38/hTERT cultures during the accelerated growth phase revealed overexpression of the c-myc and Bmi-1 oncogenes, as well as loss of p14(ARF) expression. Collectively, our results indicate that although hTERT-immortalized cells behave similarly to primary cells during the first 150 PDLs, long-term growth in culture may favor the appearance of clones carrying potentially malignant alterations. |
| Document Type: Article |
| Language: English |
| Reprint Address: Milyavsky, M (reprint author), Weizmann Inst Sci, Dept Mol Cell Biol, IL-76100 Rehovot, Israel |
Addresses:
1. Weizmann Inst Sci, Dept Mol Cell Biol, IL-76100 Rehovot, Israel
2. NCI, Human Carcinogenesis Lab, NIH, Bethesda, MD 20892 USA |
| Publisher: AMER ASSOC CANCER RESEARCH, 615 CHESTNUT ST, 17TH FLOOR, PHILADELPHIA, PA 19106-4404 USA |
| Subject Category: Oncology |
| IDS Number: 742UA |
| ISSN: 0008-5472 |
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| | | | | | | | | Record from Web of Science® | | | | | | | | | |