In vitro activity: In vitro, STF-62247 shows cytotoxicity and tumor growth inhibitory activity against wild-type VHL and VHL-deficient renal cell carcinoma (RCC) in a HIF-independent manner with IC50 of 16 μM and 0.625 μM, respectively. Moreover, STF-62247 also leads to cell death by increasing acidification and inducing autophagy in VHL-deficient cells. STF-62247 specifically induces macroautophagy and enhances the fusion of autophagosome and lysosomes to form autolysosomes by interfering with Golgi-endoplasmic reticulum transport in cells that have lost VHL. A recent study shows that induction of autophagy by STF-62247 increases sensitivity of RCC under hypoxic conditions to radiation in a VHL-dependent manner.

Kinase Assay: STF-62247 is TGN inhibitor with IC50 of 0.625μM and 16μM in RCC4 and RCC4/VHL cells,respectively.It specifically induces autophagic cell death in cells that have lost VHL, an essential mutation in the development of RCC. IC50: 0.625/16μM in RCC4 and RCC4/VHL cells,respectively.

Cell Assay: For cell viability, 100,000 cells are plated in a 12-well plate. The following day, 1.25 μM STF-62247 is added in the presence or absence of 1 mM 3-MA for 24 hours at 37 °C. Cells are trypsinized and counted by trypan blue exclusion. For XTT assays, 5000 RCC4 with and without VHL cells or 2,500 SN12C with and without VHL shRNA cells are plated in 96-well plates. The following day, vehicle (DMSO), STF-62247 is added to media by serial dilution. Four days later, the media is aspirated and XTT solution containing 0.3 mg/ml of XTT in Phenol Red-free media, 20% FCS and 2.65 mg/ml N-methyl dibenzopyrazine methyl sulfate (PMS) is added to the cells and incubated at 37 °C for 1-2 hours. Metabolism of XTT is quantified by measuring the absorbance at 450 nm on a plate reader.