Identification of a gene at 16q24.3 that restores cellular senescence in immortal mammary tumor cells

Abstract

We have mapped a cellular senescence gene, SEN16, within a genetic distance of 3 ± 7 cM, at 16q24.3. Microcell mediated transfer of a normal human chromosome 16, 16q22-qter or 16q23-qter restored cellular senescence in four immortal cell lines, derived from human and rat mammary tumors. The resumption of inde®nite cell proliferation, concordant with the segregation of the donor chromosome, con®rmed the presence of a senescence gene at 16q23-qter. While microcell hybrids were maintained in selection medium to retain the donor chromosome, sporadic immortal revertant clones arose among senescent cells. Reversion to immortal growth could occur due to inactivation of the senescence gene either by a mutation or a deletion. The analysis for chromosome 16 speci®c DNA markers, in revertant clones of senescent microcell hybrids, revealed a consensus deletion, spanning a genetic interval of approximately 3 ± 7 cM at 16q24.3.

Monochromosomal Hybrids and Chromosome Transfer: A Functional Approach for Gene Identification

“…These results are supported by observations indicating the loss of chromosome segments in SV40-transformed human fibroblasts (50). We have observed similar effects upon introduction of chromosome 16 into breast and ovarian tumor cells (51). Figure 6 shows senescent phenotype of immortal cells by the presence of senescence associated (SA) β-galactosidase activity in transformed cells containing a normal chromosome 16.…”

Identification of a YAC from 16q24 carrying a senescence gene for breast cancer cells

“…Cells in all MCF/d792t2 and LA/d792t2 colonies displayed enlarged,¯at and vacuolated morphology, identical to the phenotypes previously observed following the introduction of intact chromosome 16 into these cells (Figure 2; Reddy et al, 1999). All colonies expressed progressively increasing doubling time (or diminishing growth rate), which varied from 72 ± 96 h for MCF/ d792t2 and 48 ± 72 h for LA/d792t2 cells, eventually ending in complete growth arrest.…”

“…The most frequent LOH has been observed at 16q24.3-qter irrespective of the stage of the disease (Tsuda et al, 1994;Devilee and Cornelisse, 1994), implicating a key early role for this region in breast carcinogenesis. Introduction of chromosome 16 or segments of 16q into human and rat mammary tumor cells led to the restoration of replicative senescence (Reddy et al, 1999). Using this functional assay, cellular senescence genes have been identi®ed on at least ten di erent human chromosomes (reviewed in Oshimura and Barrett, 1997).…”

“…We have devised an experimental strategy, applying chromosome transfer into human and rodent cell lines in parallel, for the high resolution mapping of cell senescence/tumor suppressor genes (Reddy et al, 1999;Sandhu et al, 1996). Using this approach, we mapped a cell senescence gene, SEN16, within a 3 ± 7 cM genetic interval at 16q24.3 (Reddy et al, 1999).…”

“…Using this approach, we mapped a cell senescence gene, SEN16, within a 3 ± 7 cM genetic interval at 16q24.3 (Reddy et al, 1999). This mapping resolution allowed us to identify a small number of Yeast Arti®cial Chromosome (YAC) clones to construct a physical map across the 3 ± 7 cM region at 16q24.3.…”