Plectin is a regulator of prostate cancer growth and metastasis

Prostate cancer is responsible for over 30,000 US deaths annually, attributed largely to incurable metastatic disease. Here, we demonstrate that high levels of plectin are associated with localized and metastatic human prostate cancer when compared to benign prostate tissues. Knock-down of plectin inhibits prostate cancer cell growth and colony formation in vitro, and growth of prostate cancer xenografts in vivo. Plectin knock-down further impairs aggressive and invasive cellular behavior assessed by migration, invasion, and wound healing in vitro. Consistently, plectin knock-down cells have impaired metastatic colonization to distant sites including liver, lung, kidney, bone, and genitourinary system. Plectin knock-down inhibited number of metastases per organ, as well as decreased overall metastatic burden. To gain insights into the role of plectin in prostate cancer growth and metastasis, we performed proteomic analysis of prostate cancer plectin knock-down xenograft tissues. Gene set enrichment analysis shows an increase in levels of proteins involved with extracellular matrix and laminin interactions, and a decrease in levels of proteins regulating amino acid metabolism, cytoskeletal proteins, and cellular response to stress. Collectively these findings demonstrate that plectin is an important regulator of prostate cancer cell growth and metastasis.