Prostate cancer-derived CCN3 induces M2 macrophage infiltration and contributes to angiogenesis in prostate cancer microenvironment

Abstract

Tumor-associated macrophages (TAMs) are M2-polarized macrophages that infiltrate the tumor microenvironment and promote tumorigenesis. However, the mechanisms by which TAMs modulate prostate cancer (PCa) growth are poorly understood. Here, we found that expression of Nephroblastoma Overexpressed (NOV/CCN3) is upregulated in PCa cells and correlated with M2 macrophage infiltration. RAW264.7 macrophage migration was induced by conditioned media (CM) from various PCa cells in proportion to the cellular level of CCN3 expression and was inhibited by an anti-CCN3 neutralizing antibody. CCN3 and PCaCM treatment skewed RAW264.7 cell differentiation from an M1 phenotype to an M2 phenotype. PCa-derived CCN3 induced focal adhesion kinase (FAK)/Akt/NF-κB signaling in RAW264.7 cells, which resulted in VEGF expression and subsequently increased tube formation in endothelial progenitor cells. Finally, PCa-secreted CCN3 stimulated RAW264.7 cells and promoted angiogenesis in the chick chorioallantoic membrane assay (CAM), and increased tumor growth and tumor-associated angiogenesis in a PCa xenograft mouse model. Our results indicate that PCa-secreted CCN3 can recruit macrophages and skew their differentiation to an M2 phenotype. In turn, CCN3-stimulated macrophages contribute to VEGF-dependent angiogenesis. This study reveals a novel mechanism by which TAMs enhance PCa angiogenesis and identifies a potential therapeutic target for PCa.

Expression array analysis of the hepatocyte growth factor invasive program

“…This group also can be subdivided as secreted (NOV, FN1, MMP1, MMP13, SERPINE1 and TFPI), membrane (CDH3), and intracellular effector (AKAP12, PTPRM, and NEDD9) molecules. Increased NOV expression as seen in our data has been associated with enhanced PCa cell motility, PCa bone metastasis and angiogenesis [75][76][77], as well as the migration of cells derived from pancreatic cancer and melanoma [78,79]; direct effects on integrin expression, adhesion and actin cytoskeletal reorganization have been reported [80]. Upregulation of FN1 in response to HGF ligands is consistent with invasive, metastatic and therapy resistance roles for this matrix protein in breast cancer (reviewed in [81]); FN1 suppression in PC3 cells was associated with reduced tumorigenesis [82].…”

Extracellular Matrix, a Hard Player in Angiogenesis

“…CCN3 stimulates the expression of VEGF in prostate cancer cells activating the focal adhesion kinase (FAK)/PKB/NF-κB signaling pathway. Furthermore, CCN3 stimulates the recruitment of macrophages which are skewed to an M2 phenotype, thus leading to enhanced tumor angiogenesis [244]. By modifying this key cellular microenvironmental component CCN3 is thus able to deeply affect cancer growth both directly, affecting cancer cell behavior, and indirectly, affecting angiogenesis.…”

Polycomb-Mediated Disruption of an Androgen Receptor Feedback Loop Drives Castration-Resistant Prostate Cancer

“…Further, immuocytochemistry experiments have revealed cytoplasmic immunostaining of CCN3 in the epithelial compartment of human prostate tissues (15). However, to date, a majority of studies of CCN3 function in prostate cancer has focused almost exclusively on its secreted form in AR-negative cells (16–18). The roles of cytoplasmic CCN3 and potential regulation of clinically relevant AR-positive prostate cancer cells have not been investigated.…”