Vishal Chandra

Mortalin and PINK1/Parkin‐Mediated Mitophagy Represent Ovarian Cancer‐Selective Targets for Drug Development

Abstract Mortalin is an essential chaperone for the import of nuclear‐encoded proteins into mitochondria and is elevated in ovarian cancer in association with poor patient prognosis. The investigational new drug, SHetA2, interacts with mortalin releasing its client proteins. In this study, interactions of SHetA2 moieties and mortalin substrate binding domain (SBD) amino acids are demonstrated by surface plasmon resonance (SPR) and nuclear magnetic resonance (NMR) to occur at low micromolar SHetA2 concentrations that selectively kill cancer cells over noncancerous cells. In both ovarian cancer and noncancerous cells SHetA2 reduces: mitochondria import of mortalin, degradation of mortalin's mitochondrial localization sequence (MLS), mortalin/inositol 1,4,5‐trisphosphate receptors complexes and oxidative phosphorylation. In cancer cells only, SHetA2 reduces calcium levels, mitochondrial length and fusion proteins, while inducing autophagy and PTEN‐induced kinase 1 (PINK1)/PARKIN‐mediated mitophagy. Noncancerous cells exhibit increased mitochondrial branch length in response to SHetA2 and a low level of inducible autophagy that is resistant to SHetA2. Inhibition of autophagosome‐lysosome fusion reduces, or increases, SHetA2 cytotoxicity in ovarian cancer or noncancerous cells, respectively. SHetA2 inhibits mortalin and growth, and induces mitophagy in ovarian cancer xenografts and increases survival post‐surgical tumor removal. In conclusion, SHetA2 binds directly to mortalin's SBD and causes distinct responses in ovarian cancer and noncancerous cells.

Niclosamide causes lysosome-dependent cell death in endometrial cancer cells and tumors.

Endometrial cancer is the most common female cancer showing continuous rise in its incidence and mortality rate. Despite the extensive research efforts in cancer therapeutics, still there is a lack of effective treatment options and the outcome is poor for patients with advanced and recurrent endometrial cancers. In this study, we aimed to evaluate the efficacy of niclosamide (NIC) against endometrial cancer. NIC is an FDA-approved anti-helminthic drug, which has been recently extensively studied as a potent anti-cancerous agent in several cancers. The anti-cancerous activity of NIC was analyzed in-vitro (ANC3A, Hec1B, and Ishikawa endometrial cancer cell lines) by cell viability-, soft agar-, invasion- and migration- assay. The action mechanism of NIC was demonstrated by western blot analysis and immune-fluorescence imaging and validated by specific inhibitors. The in-vivo efficacy of NIC was studied in the Ishikawa xenograft animal model. NIC effectively suppressed the viability (IC