Eliminating Target Cells by Inducing Apoptosis-Related Factors Using hTERT Promoter

Inducing the complete apoptosis cascade in target cells is useful for eliminating cancer cells and for producing animal models lacking specific cell types. Neuroblastoma SH-SY5Y cells lack caspase-8 and are thus resistant to the apoptosis-inducing effects of 2DEDplusE, an engineered Fas-associated death domain protein (FADD) containing tandem death effector domains (DEDs) of FADD and lambda phage E protein. To overcome tumor cells’ resistance to apoptosisinducing factors, we produced new engineered factors—2DEDcasp8, 2DEDcasp8 DEDa, and 2DEDcasp8 DEDab—by fusing the tandem DEDs of FADD to procaspase-8 or its different segments. Of the three, 2DEDcasp8 DEDa most effectively induced apoptosis in SH-SY5Y cells. Finally, by using the human telomerase reverse transcriptase (hTERT) promoter, a known cancer cell-specific promoter, and adapting it to a mifepristone-inducing system, we expressed engineered factors that induced apoptosis in HeLa and A549 tumor cells. The same system did not induce apoptosis in normal Wi-38 and MRC-5 cells, although driving the same system with a constitutive thymidine kinase (TK) promoter induced apoptosis in both cell types.