monensin and Kidney-Neoplasms

Monensin is a metal ionophore used as anticancer agent in many types of cancer cells. In this study, therapeutic potential of monensin was evaluated in TFE3 translocated renal cell carcinoma (RCC) cell line UOK146. UOK146 cells were treated with different concentrations of monensin, and cell death was induced as shown by MTT assay. Autophagy was studied by LC3 western, FACS and LC3 puncta formation after monensin treatment. Mitochondrial potential was studied by staining with TMRM and FACS. Antimetastatic potential of monensin was checked by inhibition of wound closure and MMP7 expression at RNA level. Dead and floating cells after the 10 μM monensin treatment were observed under phase contrast microscope. FACS analysis following TMRM staining showed that mitochondrial membrane gets depolarized after monensin treatment. FACS analysis after acridine orange staining showed increased double positive (green and red) cells, and LC3 upregulation and increased LC3 punta displayed autophagy activation in UOK146 cell line after monensin treatment. These findings showed that monensin acts as antiproliferative agent, activating autophagy and downregulates PRCC-TFE3 fusion transcript in Xp11.2 translocated tumor cell line.

Topics: Autophagy; Carcinoma, Renal Cell; Cell Line, Tumor; Cell Movement; Cell Proliferation; Down-Regulation; Gene Expression Regulation, Neoplastic; Humans; Kidney Neoplasms; Matrix Metalloproteinase 7; Membrane Potential, Mitochondrial; Monensin; RNA, Messenger

Previously, we showed that monensin, Na+ ionophore, potently inhibited the growth of acute myelogenous leukemia and lymphoma cells. Here, we demonstrate that monensin inhibited the proliferation of renal cell carcinoma cells with IC50 of about 2.5 micro M. Monensin induced a G1 or a G2-M phase arrest in these cells. When we examined the effects of this drug on ACHN cells, monensin decreased the levels of CDK2, CDK6, cdc2, cyclin A and cyclin B1 proteins. p21 and p27 proteins were increased by monensin. In addition, monensin markedly enhanced the binding of p21 with CDK2 and the binding of p27 with CDK6. Furthermore, the activities of CDK2- and CDK6-associated kinase were reduced in association with hypophosphorylation of Rb protein. Monensin also induced the apoptosis in several renal cell carcinoma cells. Apoptotic process of Caki-2 cells was associated with the changes of Bcl-2, Bcl-XL, caspase-9, caspase-3, caspase-7 proteins as well as mitochondria transmembrane potential (DeltaPsim) loss. Taken together, these results demonstrate for the first time that monensin inhibits the growth of renal cell carcinoma cells via cell cycle arrest or apoptosis.

Topics: Antifungal Agents; Apoptosis; Blotting, Western; Carcinoma, Renal Cell; Caspases; CDC2-CDC28 Kinases; Cell Cycle; Cell Division; Cell Line; Cell Line, Tumor; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinase 6; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinases; Cyclins; Dose-Response Relationship, Drug; G1 Phase; G2 Phase; Humans; Inhibitory Concentration 50; Ionophores; Kidney Neoplasms; Microfilament Proteins; Microscopy, Fluorescence; Monensin; Muscle Proteins; Phosphorylation; Precipitin Tests; Retinoblastoma Protein; Sodium