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Eliminating Target Cells by Inducing Apoptosis-Related Factors Using hTERT Promoter
Abstract
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 Δ DEDa, and 2DEDcasp8 Δ DEDab ― by fusing the tandem DEDs of FADD to procaspase-8 or its different segments. Of the three, 2DEDcasp8 Δ 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.