RESUMO
BACKGROUND: Renal cancer therapies are challenging owing to the extensive spreading of this cancer to other organs and its ability to pose resistance to current medications. Therefore, drugs targeting novel targets are urgently required to overcome these challenges. The cholesterol side-chain cleavage enzyme (CYP11A1) is closely associated with steroidogenesis, and its downregulation is linked to adrenal dysfunction and several types of carcinoma. We previously found that overexpression of CYP11A1 inhibited epithelial-mesenchymal transition and induced G2/M arrest in the kidney cancer Caki-1 cell line. In this context, natural compounds that exhibit potent CYP11A1 stimulation activity can be promising therpaeutic agents for kidney cancer. METHODS: We screened a panel of 1374 natural compounds in a wound-healing assay using CYP11A1-transfected Caki-1 cells. Of these, 167 promising biologically active compounds that inhibited cancer cell migration by more than 75% were selected, and their half-maximal inhibitory concentrations (IC50) were determined. The IC50 of 159 compounds was determined and 38 compounds with IC50 values less than 50 µM were selected for further analysis. Steroid hormones (cholesterol and pregnenolone) levels in cells treated with the selected compounds were quantitated using LC-MS/MS to determine their effect on CYP11A1 activity. Western blotting for CYP11A1, autophagy signaling proteins, and ferroptosis regulators were performed to ivestigate the mechanisms underlying the action of the selected compounds. RESULTS: We screened five promising natural lead compounds that inhibited cancer cell proliferation after three screening steps. The IC50 of these compounds was determined to be between 5.9 and 14.6 µM. These candidate compounds increased the expression of CYP11A1 and suppressed cholesterol levels while increasing pregnenolone levels, which is consistent with the activation of CYP11A1. Our results showed that CYP11A1 activation inhibited the migration of cancer cells, promoted ferroptosis, and triggered autophagy signaling. CONCLUSIONS: This study indicates that the CYP11A1-overexpressing Caki-1 cell line is useful for screening drugs against kidney cancer. The two selected compounds could be utilized as lead compounds for anticancer drug discovery, and specifically for the development of antirenal cancer medication.
RESUMO
BACKGROUND: Clear cell renal carcinoma is commonly known for its metastasis propensity to outspread to other organs and is asymptomatic in the early stage. Recent studies have shown that deficiencies in CYP11A1 expression can lead to fatal adrenal failure if left untreated and are associated with downstream regulation in various cancer types. However, the molecular mechanisms of CYP11A1 and kidney cancer proliferation remain unclear. METHODS: Normal and renal carcinoma cell lines (HEK293 and Caki-1) were transfected with plasmid encoding CYP11A1 to overexpress the P450scc protein. Cell cycle distribution was investigated using flow cytometry. The expression of proteins related to C-Raf/ERK/JNK/p38 signaling pathways was examined using western blot. RESULTS: We observed that CYP11A1 overexpression suppressed the cyclin B1 and cell-division cycle 2 expression while cyclin-dependent kinases 2 and 4 were unaffected. Cancer cell migration and invasion were suppressed along with epithelial-intermediate metastatic markers Snail and Vimentin. In addition, in CYP11A1-overexpressing Caki-1 cells, cdc2/cyclinB1 was downregulated while the phosphorylation of cdc25c, a G2/M arrest-related upstream signal, was increased. The intrinsic-mitochondrial apoptosis markers were not significantly altered. We also identified that the C-Raf/ERK/JNK/p38 pathway is an important pro-apoptotic mechanism in CYP11A1-overexpressing cell-based models. Our results suggest that CYP11A1 overexpression recovered the disturbed cell cycle arrest distribution in renal carcinoma cell line Caki-1 through G2/M arrest and C-Raf/ERK/JNK pathway. CONCLUSIONS: Our findings may suggest promising new therapeutic targets to suppress kidney cancer proliferation without affecting normal cells, eventually improving the survival of patients with cancer.
