Project description:Prostate cancer (PCa) remains the malignancy with the highest morbidity in men (1). Although early-stage PCa usually causes no symptoms, cancer cells in prostate glands readily metastasize to bones, lymph nodes, lungs, and liver during PCa progression (2). Common strategies, including surgery, radiation therapy, and androgen-deprivation therapy, are promising treatments for early-stage PCa. However, advanced PCa still lacks effective therapeutic strategies (3-5). Thus, researchers are currently focused on inhibiting tumor progression to explore effective therapeutic strategies for PCa treatment (6, 7). Cancer-associated fibroblasts (CAFs), stromal cells derived from normal fibroblasts or epithelia, are one of the major cellular components in the tumor microenvironment (8, 9). Compared with normal fibroblasts, CAFs are activated with increased expression of key protein markers, such as α-SMA, FAP, vimentin and S100A4 protein (10, 11). In the tumor microenvironment, CAFs secrete various growth effectors or cytokines to the extracellular matrix and thereby promote tumor progression by directly enhancing cancer cell growth, angiogenic induction, the extracellular matrix modification, and tumor-promoting inflammatory mediation (11-14). Notably, CAFs could act as an immunosuppressive mediator for the formation of an immunosuppressive tumor environment by recruiting and activating multiple immune cells (15). As such, CAFs might be a potential target in anti-tumor immunotherapy (16, 17). Currently, increased research has focused on inhibiting the immunosuppressive function of prostate cancer-associated fibroblasts (prostate CAFs), which may suggest therapeutic strategies for PCa (18, 19). Polysaccharides from Lentinus edodes are known to exhibit potent anti-tumor and immunomodulatory functions. The anti-tumor mechanisms of L. edodes polysaccharides include regulating the innate immune system by mediating CAF function, preventing tumorigenesis, or directly killing tumor cells via cell cycle regulation or apoptotic induction (20-22). Our previous studies isolated a novel polysaccharide component (MPSSS) from L. edodes. We found the secretome of prostate CAFs treated with MPSSS could inhibit the proliferation of CD4+ and CD8+ T cells, which suggested that MPSSS could prevent the immunosuppressive function of prostate CAFs (22). However, although the secretome of MPSSS-treated prostate CAFs inhibit the proliferation of T cells, how the secretome of MPSSS-treated prostate CAFs affect PCa progression is still unclear. The secretome defines as all proteins secreted by the organism or living cells into the extracellular space, which consists of soluble proteins and extracellular vesicles (EVs) (23). The secretome of prostate CAFs pays vital roles in PCa tumor origination, progression (24, 25). Since EVs contains various molecules (proteins, RNA, DNA and lipid) (26), we speculate that soluble proteins and EVs of prostate CAFs might have the different influence on PCa cells. In this study, the secretome of prostate CAFs untreated/treated with MPSSS were separated into the high molecular weight secretome (>100 kD) and the low molecular weight secretome (3-100 kD) using 100 kD and 3kD MWCO memberane filtration to narrow down the range of active components. The high molecular weight secretome contained extracellular vesicles (EVs) and large soluble proteins, while the low molecular weight secretome contained the small soluble proteins. The secretome of prostate CAFs untreated/treated with MPSSS were used to explore the underlying function and molecular mechanism using quantitative proteomics and multiple biochemical approaches.
2021-03-22 | PXD023689 | Pride
Ophelia Papoulas 
