Supplementary Figure S2. The effects of metformin on prostate stroma cells. (A) The ratio of epithelial cells to stroma cells in the mice at week 12, 25 and 37. (B) WPMY-1 cells were seeded in 96-well plates with 0.5Ã-105 cells per well in growth media with or without metformin (20mM). Cell viabilities were estimated by CCK8 every other day. (C and D) WPMY-1 cells were treated with different concentrations of metformin and the numbers of cells at different stages of the cycle were analyzed by ï¬,ow cytometry (C), or stained with PI and FITC-labelled Annexin V and subsequently underwent ï¬,ow cytometry analysis to determine the percentage of apoptotic cells (D).
ARTICLE ABSTRACT
Purpose: Inflammatory infiltration plays important roles in both carcinogenesis and metastasis. We are interested in understanding the inhibitory mechanism of metformin on tumor-associated inflammation in prostate cancer.Experimental Design: By using a transgenic adenocarcinoma of the mouse prostate (TRAMP) mouse model, in vitro macrophage migration assays, and patient samples, we examined the effect of metformin on tumor-associated inflammation during the initiation and after androgen deprivation therapy of prostate cancer.Results: Treating TRAMP mice with metformin delays prostate cancer progression from low-grade prostatic intraepithelial neoplasia to high-grade PIN, undifferentiated to well-differentiated, and PIN to adenocarcinoma with concurrent inhibition of inflammatory infiltration evidenced by reduced recruitment of macrophages. Furthermore, metformin is capable of inhibiting the following processes: inflammatory infiltration after androgen deprivation therapy (ADT) induced by surgically castration in mice, bicalutamide treatment in patients, and hormone deprivation in LNCaP cells. Mechanistically, metformin represses inflammatory infiltration by downregulating both COX2 and PGE2 in tumor cells.Conclusions: Metformin is capable of repressing prostate cancer progression by inhibiting infiltration of tumor-associated macrophages, especially those induced by ADT, by inhibiting the COX2/PGE2 axis, suggesting that a combination of ADT with metformin could be a more efficient therapeutic strategy for prostate cancer treatment. Clin Cancer Res; 24(22); 5622–34. ©2018 AACR.
