ASSOCIATION BETWEEN HSP60 MESSENGER-RNA LEVELS AND CISPLATIN RESISTANCE IN HUMAN HEAD AND NECK-CANCER CELL-LINES

Development of resistance to cisplatin (cDDP) is a major obstacle in t he cure of many cancers. Recently, a cDNA from cDDP-resistant human ov arian carcinoma cells was identified as the mitochondrial hsp60 chaper onin. The aim of this study was to determine the changes in expression of hsp60 during selection for cDDP resistance in two head and neck ca ncer cell lines, UMSCC5 and UMSCC10b and whether the emergence of resi stance could be correlated with the level of hsp60 expression. We have selected cDDP-resistant variants of two squamous cell carcinoma cell lines, the UMSCC5 and UMSCC10b with levels of resistance varying from 1.5 to 6-fold. Concomitant with the emergence of resistance, the basal level of hsp60 increased 2 to 3-fold. In addition, less cDDP resistan ce as well as lower hsp60 levels were detected in cDDP resistant varia nts of the UMSCC10b cell line when selected in the presence of tamoxif en, suggesting a correlation between the intrinsic level of hsp60 expr ession and cDDP resistance. Using linear regression analysis both UMSC C5 and UMSCC10b cell lines demonstrated a high degree of correlation w ith coefficients of 0.91 and 0.90, respectively. In conclusion, the ex pression of hsp60 was closely related to the development of cDDP resis tance and could be used as a marker for the emergence of cDDP resistan ce.