The effect of 3-(5′-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1) on cell viability under hypoxia

Purpose: The synthetic compound 3-(5′-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1) reduces the protein stability of hypoxia-inducible factor (HIF)-1α and can serve as a potential anticancer agent. Our previous study elucidated that YC-1 decreased the protein level of HIF-1α and inhibited cell proliferation under normoxic conditions. In the present study, we explored the inhibitory effect of YC-1 on the regulation of HIF-1α and cell survival under hypoxia. Methods: Chemical and physical hypoxia using cobalt chloride and an anaerobic incubator, respectively, was induced in the photoreceptor cell line 661W. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and morphological observation were used to analyze cell survival. Flow cytometry with a LIVE/DEAD cell viability assay and annexin V was used to determine the number of live and dead cells or cell apoptosis, respectively. Cell proliferation was analyzed with high-content screening of MKI67 (K_i-67) immunofluorescent staining. Immunoblotting and a quantitative reverse-transcription PCR were used to assess the protein and mRNA levels, respectively. Results: Our results showed that 661W cells exposed to YC-1 decreased cell survival th rough the induction of cell apop-tosis and cell-cycle arrest under hypoxia. We also found that YC-1 reduced the HIF-1α protein level after 2 h of hypoxia, but the mRNA level of HIF-1α was not affected. In addition, YC-1 significantly increased levels of p53, the proapoptotic gene BCL2-associated X protein (Bax), and cell proliferation-related gene, cyclin-dependent kinase inhibitor 1A (p21) mRNAs under hypoxia. Conclusions: Unlike normoxia, YC-1 not only inhibited cell proliferation but also induced cell death under hypoxia. We also found that YC-1 inhibited hypoxia-induced HIF-1α and partially affected hypoxia-regulated gene expression.