Ting Harold, Deep Gagan, Kumar Sushil, Jain Anil K, Agarwal Chapla, Agarwal Rajesh
Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences and.
University of Colorado Cancer Center, University of Colorado Denver Anschutz Medical Campus, 12850 East Montview Blvd, V20-2118, Box C238, Aurora, CO 80045, USA.
Carcinogenesis. 2016 Jun;37(6):589-599. doi: 10.1093/carcin/bgw039. Epub 2016 Apr 2.
Tumor microenvironment plays an essential role in prostate carcinogenesis and offers novel opportunities to prevent and treat prostate cancer (PCA). Here, we investigated the ability of cancer-associated fibroblasts (CAFs) to promote PCA progression, and silibinin efficacy to target this response. We collected conditioned media from CAFs treated with vehicle or silibinin, and labeled as control conditioned media (CCM) or silibinin-treatment conditioned media (SBCM), respectively. Next, we characterized the effect of CCM and SBCM treatment in several PCA cell lines (RWPE-1, WPE-1 NA-22, WPE-1 NB-14 and PC3). Result showed that compared with SBCM, CCM significantly reduces E-cadherin expression and increases invasiveness and clonogenicity in PCA cells. Further molecular studies identified monocyte chemotactic protein-1 (MCP-1) as the key component of CCM that promotes PCA invasiveness, whereas silibinin treatment strongly reduced MCP-1 expression in CAFs by inhibiting the DNA-binding activity of MCP-1 transcriptional regulators-nuclear factor-kappaB and AP-1. In vivo, silibinin feeding (200mg/kg body weight) strongly reduced TRAMPC1 allografts growth (by 68%) in syngeneic C57Bl/6 mice. TRAMPC1 tumor analysis showed that silibinin reduced MCP-1 and CAFs' biomarkers (fibroblast activation protein, α-smooth muscle actin, transforming growth factor beta 2, vimentin etc.) and significantly modulated the recruitment of immune cells in the tumor microenvironment. Similar inhibitory effects of silibinin on MCP-1 and immune cells recruitment were also observed in TRAMP PCA tissues with reported silibinin efficacy. Overall, our data suggest that silibinin can target CAF-mediated invasiveness in PCA by inhibiting MCP-1 secretion. This, in turn, was associated with a reduction in immune cell recruitment in vivo along with a marked reduction in tumor growth.
肿瘤微环境在前列腺癌发生过程中起着至关重要的作用，并为预防和治疗前列腺癌（PCA）提供了新的机会。在此，我们研究了癌症相关成纤维细胞（CAFs）促进PCA进展的能力，以及水飞蓟宾针对这种反应的疗效。我们收集了用载体或水飞蓟宾处理的CAFs的条件培养基，分别标记为对照条件培养基（CCM）或水飞蓟宾处理条件培养基（SBCM）。接下来，我们表征了CCM和SBCM处理对几种PCA细胞系（RWPE-1、WPE-1 NA-22、WPE-1 NB-14和PC3）的影响。结果表明，与SBCM相比，CCM显著降低了PCA细胞中E-钙黏蛋白的表达，并增加了其侵袭性和克隆形成能力。进一步的分子研究确定单核细胞趋化蛋白-1（MCP-1）是CCM促进PCA侵袭的关键成分，而水飞蓟宾处理通过抑制MCP-1转录调节因子核因子-κB和AP-1的DNA结合活性，强烈降低了CAFs中MCP-1的表达。在体内，给同基因C57Bl/6小鼠喂食水飞蓟宾（200mg/kg体重）可显著降低TRAMPC1同种异体移植物的生长（降低68%）。TRAMPC1肿瘤分析表明，水飞蓟宾降低了MCP-1和CAFs的生物标志物（成纤维细胞活化蛋白、α-平滑肌肌动蛋白、转化生长因子β2、波形蛋白等），并显著调节了肿瘤微环境中免疫细胞的募集。在具有水飞蓟宾疗效报道的TRAMP PCA组织中也观察到水飞蓟宾对MCP-1和免疫细胞募集的类似抑制作用。总体而言，我们的数据表明水飞蓟宾可以通过抑制MCP-1分泌来靶向CAF介导的PCA侵袭性。这反过来又与体内免疫细胞募集的减少以及肿瘤生长的显著降低相关。
