Prostate cancer-secreted CCN3/NOV promotes osteoblast differentiation via Wnt signal pathway and miR-608 suppression

Objective: NOV/CCN3 is a secreted protein that interacts with the extracellular matrix and thereby regulates many cellular functions, including cell division, chemotaxis, apoptosis, adhesion, motility, and ion transport. Recently, CCN3 expression have been implicated in progression of various cancer, and our previous study indicates that CCN3 increases the migration and invasion of prostate cancer (PCa) cells by regulation of ICAM-1 expression. Our research group also review the pivotal role CCN3 in bone metastasis of PCa by modulating the tumor-bone microenvironment. Moreover, evidence has highlighted the pivotal role of osteoblasts in osteoblastic bone metastasis in PCa. Material and Methods: MC3T3-E1 osteoblast cells were incubated with conditioned media collected from PCa cells. The cell proliferation and osteogenic differentiation were evaluated by MTT assay and Alizarin red S staining. The osteogenic markers were also examined by Western blot and QPCR. Furthermore, the Wnt activation was tested by Western blot and luciferase reporter assay. Pretreatment with chemical inhibitor of Wnt was used to determine the regulatory role of Wnt in osteogenic differentiation in response to PCa CM. Finally, expression of miR-608 was investigated by QPCR and mimic miR-608 was used to certify the role of miR-608 in osteogenic differentiation in response to PCa CM. Results: Here, we show that PCa-secreted CCN3 increases expression of osteoblastic differentiation factors including BMPs, Runx2 and Osterix. Furthermore, this effect is regulated by Wnt signal pathway or miR-608 repression. The present study supposes that PCa-secreted CCN3 can promote osteoblastic bone metastasis in PCa by activating Wnt signal and inhibition of miR-608 expression. Our present study provides an opportunity to develop CCN3 as a therapeutic target that prevents bone metastasis in PCa. Citation Format: Po-Chun Chen, Chia-Chia Chao, An-Chen Chang, Chih-Hsin Tang. Prostate cancer-secreted CCN3/NOV promotes osteoblast differentiation via Wnt signal pathway and miR-608 suppression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-099.