Cell Survival Advantage in Cadmium Induced Carcinogenesis

项目摘要 接触镉(Cd)与包括前列腺癌在内的一系列人类发病有关 (上限)。镉暴露与前列腺血清抗原(PSA)异常之间明确的剂量-反应关系 据报道，接触镉的男性中有帽子的标志。然而，潜在的分子机制 接触Cd后的恶性细胞转化尚不确定，而Cd与 而CAP在临床前和临床模型中都得到了很好的建立。此应用程序的目标是 探讨镉引起恶性细胞转化的潜在机制(从正常到 转化细胞)和CD转化细胞(转化细胞)在肿瘤发生发展中的作用 细胞与肿瘤发生的关系)。我们的初步结果表明，在细胞转化过程中，镉暴露 诱导内质网(ER)应激，触发应激信号转导通路的磷酸化，包括 PERK和eIF2-α导致ATF4的激活，并启动自噬的诱导，保护CD- 受损的细胞。然而，自噬标志物(ATG-12和ATG-16L，LC3B和LAMP1)的诱导被观察到 在镉处理的细胞中，由于自噬小体和自溶酶体失败，自噬过程是不完整的 融合，这使得受损的细胞可以增殖转化。P62在Cd中的大量积累- 处理过的细胞，这也证实了有缺陷的自噬。通过siRNA或 药物抑制物显著抑制转化细胞的生长，但对镉处理的正常细胞无明显抑制作用 细胞或CD转化细胞提示EGFR激活起关键作用，仅在细胞 转型。CD转化细胞产生的移植瘤组织高水平表达ATF-4， EGFR、p62、LC3B与体外培养结果的相关性此外，这些蛋白的表达增加(ATF- 4、EGFR、P62和LC3B)与Gleason Sum的符合性比较 前列腺增生症和“正常”的邻近组织。根据研究结果，我们假设慢性接触 前列腺上皮细胞对CD的依赖导致内质网应激，继而导致自噬缺陷，导致 导致恶性细胞转化和转化细胞EGFR激活的受损细胞的存活 在肿瘤的发生中起着重要的作用。提出了三个具体目标：目标-1：证明CD引起 内质网应激，继而在前列腺上皮细胞转化过程中诱导缺陷自噬。 目的2：研究缺陷自噬对镉损伤细胞存活率的保护作用 在前列腺上皮细胞转化过程中。目的-3：研究镉致小鼠肿瘤的模型 并验证人类前列腺标本中的分子标记。

Project Summary Exposure to cadmium (Cd) is associated with a spectrum of human pathogenesis including the prostate cancer (CaP). A clear dose-response relation between Cd-exposure and abnormal prostate serum antigen (PSA), a marker for CaP have been reported in men exposed to Cd. However, the molecular mechanism underlying the malignant cell transformation following Cd exposure is yet to be determined, while the association between Cd and CaP in both pre-clinical and clinical models are well established. The goal of this application is to investigate the underlying mechanism of how Cd causes malignant cell transformation (from normal to transformed cells) and on the development of tumorigenesis by the Cd-transformed cells (transformed cells to tumorigenesis). Our preliminary results suggest that during cellular transformation, Cd exposure induced endoplasmic reticulum (ER)-stress, which triggered the phosphorylation of stress transducers including PERK and eIF2-α resulted in the activation of ATF4 and initiate the induction of autophagy that protects Cd- damaged cells. Although, induction of autophagy markers (Atg -12 and Atg-16L, LC3B and Lamp1) were seen in Cd-treated cells, the autophagy process is incomplete, due to failure autophagosome and autolysosome fusion, which allowed the damaged cell to proliferate for transformation. A massive accumulation of p62 in Cd- treated cells, which also confirmed the defective autophagy. Silencing EGFR activation by siRNA or pharmacological inhibitors significantly inhibited the growth in transformed cells, but not in Cd-treated normal cells or Cd- transforming cells suggesting that EGFR activation plays a critical role, only after cellular transformation. Xenograft tumor tissues generated by Cd-transformed cells expressed high levels of ATF-4, EGFR, p62 and LC3B in correlation with in vitro findings. Moreover, increased expression of the proteins (ATF- 4, EGFR, p62, and LC3B) in human CaP specimen’s agreement with Gleason sum in comparison with benign prostatic hyperplasia and “normal” adjacent tissues. Based on the results we hypothesize that Chronic exposure of prostate epithelial cells to Cd causes ER-stress and subsequently defective autophagy, leading to increased survival of damaged cells that result in malignant cell transformation and in transformed cell EGFR activation play a significant role in tumorigenesis. Three specific aims are proposed: Aim-1: To demonstrate that Cd causes ER-stress which in turn induced defective autophagy during the transformation of prostate epithelial cells. Aim 2: Investigate the protective role of defective autophagy, which increases the survival of Cd-damaged cells during the transformation of prostate epithelial cells. Aim-3: study Cd-induced tumorigenesis in mouse models and validate the molecular markers in human prostate specimens.