ASSIGNMENT OF 2 HUMAN EPIDERMAL SQUAMOUS-CELL CARCINOMA CELL-LINES TOMORE THAN ONE COMPLEMENTATION GROUP FOR THE IMMORTAL PHENOTYPE

Two human cell lines derived from squamous cell carcinomas (SCCs) of t he epidermis, SCC-12 clone F and SCC-13 clone Y, were made to be indep endent of the Swiss 3T3 feeder layer to perform somatic-cell genetic e xperiments. We fused these SCC lines with normal human fibroblasts, an d all resulting hybrids senesced after completing 12-17 population dou blings, suggesting that in part, immortalization of the keratinocyte d uring SCC development results from the loss of gene function. We also tested whether these two SCC lines mapped to known complementation gro ups for immortality by fusing them with representatives of groups A (G M847), B (HeLa), and C (143B), but most of these hybrids were indistin guishable from those derived from homotypic crosses set up as immortal hybrid controls. As reported by others, fusions of cell lines from di fferent complementation groups-143B (group C) x HeLa (group B) or GM84 7 (group A) x HeLa (group B)-resulted in predominantly senescent hybri ds. Our results confirmed and extended previous observations by others that the phenomenon of senescence is dominant to that of immortality, but they did not allow us to assign either of the SCC lines we studie d to a complementation group for immortality. (C) 1994 Wiley-Liss, Inc .