Aberrant expression of transforming growth factor-β1 (TGF-β1) is associated with renal cell carcinoma (RCC) progression by inducing cancer metastasis. However, the downstream effector(s) in TGF-β signaling pathway is not fully characterized. In the present study, the elevation of secreted protein acidic and rich in cysteine (SPARC) as a TGF-β regulated gene in RCC was identified by applying differentially expressed gene analysis and microarray analysis, we further confirmed this result in several RCC cell lines. Clinically, the expression of these two genes is positively correlated in RCC patient specimens. Furthermore, elevated SPARC expression is found in all the subtypes of RCC and positively correlated with the RCC stage and grade. In contrast, SPARC expression is inversely correlated with overall and disease-free survival of patients with RCC, suggesting SPARC as a potent prognostic marker of RCC patient survival. Knocking down SPARC significantly inhibits RCC cell invasion and metastasis both in vitro and in vivo. Similarly, in vitro cell invasion can be diminished by using a specific monoclonal antibody. Mechanistically, SPARC activates protein kinase B (AKT) pathway leading to elevated expression of matrix metalloproteinase-2 that can facilitate RCC invasion. Altogether, our data support that SPARC is a critical role of TGF-β signaling network underlying RCC progression and a potential therapeutic target as well as a prognostic marker.
Journal of cellular physiology. 2020 Aug 11 [Epub ahead of print]
Ji-Ming Bao, Qiang Dang, Chun-Jung Lin, U-Ging Lo, Boris Feldkoren, Andrew Dang, Elizabeth Hernandez, Fei Li, Vandana Panwar, Cheng-Fan Lee, Jun-Jie Cen, Bing Guan, Vitaly Margulis, Payal Kapur, Rolf A Brekken, Jun-Hang Luo, Jer-Tsong Hsieh, Wan-Long Tan
Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, China., Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas., Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas., Department of Urology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China., Division of Surgical Oncology, Department of Surgery and Pharmacology, Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, Texas.