Proteomic signatures of angiogenesis in androgen-independent prostate cancer.

INTRODUCTION: The observation that angiogenesis, the process of new blood vessel formation, in healthy prostate and early prostate cancer is androgen-dependent gave rise to significant questions on how hypervascularization and increased angiogenesis is also achieved at the molecular level in advanced androgen-independent prostate cancer. The exact paracrine molecular network that is hardwired into the proteome of the endothelial and cancer subpopulations participating in this process remains partially understood.
METHODS: Here, we interrogated the signaling pathways and the molecular functional signatures across the proteome of endothelial cells after interacting with various secretomes produced by androgen-dependent and -independent prostate cancer cells.
RESULTS: We found the significant overexpression (P < 0.05) of prominent markers of angiogenesis, such as vonWillebrand factor (vWF) (∼ 2.5-fold) and CD31 (∼ 2-fold) in HUVECs stimulated with conditioned media from the androgen-independent prostate cancer cell line PC3. By mining the proteome of PC3 conditioned media, we discovered a signature of chemokine CXC motif ligands (i.e., CXCL3, CXCL5, CXCL6 and CXCL8) that could potentially coordinate increased angiogenesis in androgen-independent prostate cancer and verified their increased expression (P < 0.05) in both in vitro and xenograft models of androgen-independence. DISCUSSION: Our findings form the basis for understanding the regulation of crucial metastatic phenomena during the transition of androgen-dependent prostate cancer into the highly aggressive, androgen-independent state and provide further insight on potential therapeutic targets of cancer-related angiogenesis.