N-alpha-Tosyl-L-lysine chloromethyl ketone hydrochloride

N-alpha-Tosyl-L-lysine chloromethyl ketone (TLCK), a trypsin like protease inhibitor, sensitizes HeLa cells to Fas-mediated cell death. In Vitro: N-alpha-Tosyl-L-lysine chloromethyl ketone exhibits an inhibitory effect on IFN-γ activities. The effect of TLCK is studied on the IFN-γ sensitization of HeLa cells towards cell death mediated by anti-Fas. Lower concentration of anti-Fas (10 ng/mL) are used to examine the interaction among the three effectors simultaneously, that is, anti-Fas, TLCK and IFN-γ. TLCK by itself up to 50 μM concentration exhibits a small decrease in cell viability. Beyond 50 μM, a dose dependent decrease in cell viability is observed. IFN-γ slightly reduces cell viability on its own. Addition of anti-Fas (10 ng/mL) results in a slight decrease in cell survival, which is enhanced more than additively in the presence of TLCK, most prominently between 50 and 100 μM. Upon addition of both anti-Fas and IFN-γ, a decrease (≈46%) in cell viability is observed. Moreover, the decrease in cell survival is further enhanced upon addition of higher concentrations of TLCK, 25 μM and more^[1].