Exploring the anticancer potential of hydrogen sulfide and BAY‑876 on clear cell renal cell carcinoma cells: Uncovering novel mutations in VHL and KDR genes among ccRCC patients.

The aim of the present study was to determine the cytotoxic effect of BAY-876 and NaSH alone or in combination with sunitinib against the 786-O cell line (renal adenocarcinoma). The IC50 of sunitinib, BAY-876 and NaSH were estimated. Cells were cultured in a 96-well plate and then different concentration of each drug alone was exposed for different incubation time; afterwards, cell cytotoxicity was measured using Cell Counting Kit-8 kit. The IC50 for each drug was used in next experiment to determine the influence of drug combinations. Furthermore, to observe the effect of mutations of few driver genes in development of clear cell renal cell carcinoma (ccRCC), direct sanger sequencing was used to find single nucleotide polymorphisms in exon 1 and exon 13 of tumor suppressor gene Von Hippel Lindau (VHL) and kinase insert domain receptor (KDR) genes respectively in ccRCC formalin fixed paraffin embedded block samples. The results revealed that the IC50 for sunitinib (after 72 h), BAY-876 (after 96 h) and NaSH (after 48 h) was 5.26, 53.56 and 692 µM respectively. The cytotoxic effect of sunitinib and BAY-876, sunitinib and NaSH combinations after 24- and 48-h incubation respectively was significantly higher (P<0.05) compared with the control group as well as to sunitinib group alone. These results proved that each of BAY-876 and NaSH have anticancer effect; thus, they could be used in future for ccRCC treatment purpose. Furthermore, direct sequencing results demonstrated unrecorded mutations of VHL and KDR genes is 43.7 and 31.5% of cases respectively. These findings confirmed the leading role of VHL gene in development of ccRCC and the crucial role of KDR gene in angiogenesis and drug resistance.