CYR61 Expression Is Induced by IGF1 and Promotes the Proliferation of Prostate Cancer Cells Through the PI3/AKT Signaling Pathway.

Cysteine-rich angiogenic inducer 61 (CYR61) promotes prostate cancer (PCa) cell growth, but its role in disease progression remains unclear. Given its insulin-like growth factor (IGF)-binding domain and the known involvement of insulin-like growth factor-1 (IGF1) in PCa, we investigated the molecular interplay between CYR61 and IGF1. CYR61 was silenced using small interfering RNA (siRNA) in prostate carcinoma 3 (PC3), lymph node carcinoma of the prostate (LNCaP), and androgen receptor (AR)-positive 22Rv1 cells, followed by assessments of their proliferation, viability, colony formation, migration, and signaling pathway activation. CYR61 knockdown significantly reduced cell growth, viability, prostasphere formation, and migration across all three cell lines. Mechanistically, CYR61 silencing inhibited PI3K/AKT signaling but had no effect on MAPK activation. In addition, treatment with recombinant IGF1 induced CYR61 expression in a time-dependent manner, and the inhibition of PI3K/AKT signaling suppressed both CYR61 expression and cell proliferation. These findings suggest that IGF1 promotes PCa progression through CYR61 and that CYR61 may serve as a potential therapeutic target for limiting tumor growth and metastasis.