Abstract 690: An anti-leprosy drug, clofazimine, targets Wnt/β-catenin pathway in cadmium-transformed benign prostatic hyperplasia cells
Authors: Jain Rifika , Munirathinam Gnanasekar 
Published: June 2022

Prostate cancer (PCa) is one of the most prevalent cancers among men in America, being second only to skin cancer. Every year 1.6 million men are diagnosed with PCa and 366,000 men die of PCa. PCa is associated to various risk factors that include old age, ethnicity, family history, lifestyle, diet, environmental and occupational exposures. Cadmium (Cd), a well-known metal carcinogen is one of the most copious occupational and environmental pollutant found in air, soil, dietary products, and tobacco. Cd is implicated in the carcinogenesis of PCa, but the mechanism remains elusive. To explore new targets for Cd induced PCa, chronic exposure of 10µM of Cd for over a year induced malignant transformation of benign prostatic hyperplasia (BPH1) cells which was used as a cellular model in this study. The Cd transformed BPH1 cells named as BPH-Cd were confirmed for tumorigenic characteristics by performing clonogenic assay, spheroid growth assay and wound healing experiments. BPH-Cd cells were further subjected to genomic analysis to identify signaling networks that are deregulated in the carcinogenesis of Cd. Our data suggested that one of the potential underlying mechanism of Cd carcinogenesis may be due to the upregulation of Wnt-3A and β-catenin pathway. In addition, Cd also activated stemness-related genes such as ALDHA1, NANOG and Oct1. Next, to determine whether targeting Wnt/β-catenin pathway in BPH-Cd could disrupt the oncogenic potential of these cells, Clofazimine, a FDA-approved anti-leprosy drug known to inhibit broad range of Wnt-dependent cancers were explored in this study. Cell viability assay indicated the inhibition of cell growth of BPH-Cd cells by Clofazimine in a dose-dependent manner with an IC50 value of 5µM. Furthermore, Clofazimine robustly inhibited the tumorigenesis of BPH-Cd as observed in colony formation assay. Of note, In-vitro 3D spheroid assay suggested that Clofazimine decreased the size of spheroids with increasing doses. Clofazimine also showed cell cycle arrest by flow cytometry in G2/M phase in BPH-Cd cells. Confocal imaging of Wnt-3A suggested a decrease in the intensity of expression with increasing doses of clofazimine in BPH-Cd treated cells. Western blot analysis of Clofazimine treated BPH-Cd cells showed downregulation of CDK2, increase in cleaved PARP-1 and upregulation of p21. Importantly, Clofazimine also displayed potent anti-cancer effects on hormone driven (androgen-dependent) LNCaP human prostate cancer cells by inhibiting the cell viability, clonogenic ability and inducing G2/M cell cycle arrest in this cell line. Taken together, our study suggests that Clofazimine could be a potential chemopreventive and anti-prostate cancer agent which warrants further evaluation for its clinical application.

Citation Format: Rifika Jain, Gnanasekar Munirathinam. An anti-leprosy drug, clofazimine, targets Wnt/β-catenin pathway in cadmium-transformed benign prostatic hyperplasia cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 690.