The impact of alcohol-induced ATF6-mediated ER stress and Golgi disorganization on pro-metastatic glycosylation of integrins in prostate cancer

摘要 前列腺癌(PCA)风险和饮酒之间的联系一直备受争议。我们最近 在对流行病学数据的广泛评估中发现，自PSA检测时代开始以来，大多数 研究表明，饮酒与前列腺癌风险密切相关。尽管有这种流行病学支持， 人们对酒精与前列腺癌风险、进展和死亡率之间的潜在机制知之甚少。Dr。 Petrosyan引入了“onco-Golgi”的概念，在这里高尔基体变得支离破碎，导致改变 糖蛋白的糖基化和运输。此外，这种高尔基人的解体与激活 转录因子6(ATF6)介导的内质网应激。这会导致血浆含量增加 高尔基糖基转移酶异常糖基化αv整合素的膜(PM)表达 乙酰氨基葡萄糖转移酶-V(MGAT5)。重要的是，这些MGAT5修饰的整合素与 五聚体Galectin-3，导致PM保留率增加这反过来又调节了肿瘤细胞的行为， 包括粘连和迁移，这促进了前列腺癌向淋巴结和远处的扩散 器官。我们发现乙醇(Etoh)处理加剧了高尔基体组织的破坏和前列腺癌组织。 重度酗酒者MGAT5表达和PM整合素αv水平较高。我们建议Etoh提升 通过增加整合素αv介导的前列腺癌进程来实现前列腺癌的致死性。肿瘤细胞中整合素αv糖基化的改变 酒精对高尔基体的破坏作用预计会加剧高尔基体。初步数据显示 乙醇处理后高尔基体片段数与整合素αv质膜强度的正相关 多西紫杉醇耐药的PCa细胞。重要的是，我们发现PCA高尔基体的解体是由自噬驱动的 自噬抑制剂羟基氯喹(HCQ)可以恢复晚期PCa细胞中致密的高尔基体。 我们还发现，ATF6介导的内质网应激导致低糖基化、高甘露糖的表达。 (高人)整合素通过内质网-质膜连接进入质膜。ATF6的耗竭降低了高血压病患者的数量 PM和ER-PM连接上的整合素，以及减少ER-PM通信的总数。 我们已经证实了HCQ对高尔基体修复和ATF6抑制内质网应激的协同作用 耗竭在防止原位肿瘤生长和转移中的作用。这些令人兴奋的数据让我们预料到类似的 联合治疗将减少Etoh给药的促转移作用。我们观察到 在乙醇和HCQ处理的细胞中拯救高尔基体形态，表明Golgiphagy，被阻断 HCQ参与了乙醇诱导的高尔基体解体。此外，HCQ还可恢复PM整合素αv的水平 与对照细胞相比。我们预计联合使用HCQ治疗和ATF6的消耗将有效地减弱 无水乙醇对前列腺癌侵袭转移的影响总体而言，这些数据将揭示之前的 酒精促进前列腺癌生长和转移的机制未知，并提供了一个潜在的 有效的治疗策略。

Abstract The link between prostate cancer (PCa) risk and alcohol consumption has long been debated. We recently found in an extensive assessment of the epidemiologic data that, since the onset of the PSA testing era, most studies indicate alcohol consumption is strongly associated with PCa risk. Despite this epidemiologic support, little is known about the underlying mechanisms linking alcohol to PCa risk, progression, and mortality. Dr. Petrosyan introduced the concept of "onco-Golgi," where the Golgi becomes fragmented, resulting in altered glycosylation and trafficking of glycoproteins. Additionally, this Golgi disorganization is linked to activating transcription factor 6 (ATF6)-mediated Endoplasmic Reticulum (ER) stress. This results in increased plasma membrane (PM) expression of αv integrins abnormally glycosylated by Golgi glycosyltransferase, N- acetylglucosaminyltransferase-V (MGAT5). Importantly, these MGAT5-modified integrins form clusters with pentameric Galectin-3, resulting in increased retention on the PM. This, in turn, modulates tumor cell behavior, including adhesion and migration, which promotes prostate tumor dissemination to lymph nodes and distant organs. We have found that ethanol (EtOH) treatment aggravates Golgi disorganization and PCa tissues from heavy alcoholics have higher MGAT5 expression and PM Integrin αv levels. We propose that EtOH promotes PCa lethality by increasing Integrin αv-mediated PCa progression. Altered glycosylation of Integrin αv in the onco- Golgi is expected to be exacerbated by alcohol's disorganizing effect on Golgi. Preliminary data demonstrate a positive correlation between the number of Golgi fragments and the PM intensity of Integrin αv in EtOH-treated docetaxel-resistant PCa cells. Importantly, we have found that PCa Golgi disorganization is autophagy-driven and that the autophagy inhibitor, Hydroxychloroquine (HCQ), restores the compact Golgi in advanced PCa cells. We have also shown that ATF6-mediated ER stress results in expression of underglycosylated, high-Mannose (high-Man) integrins to the PM through ER-PM junctions. Depletion of ATF6 decreases the amount of high-Man integrins on the PM and in ER-PM junctions, as well as reduces the total number of ER-PM communications. We have demonstrated the synergistic effect of Golgi restoration by HCQ and ER stress inhibition by ATF6 depletion in preventing orthotopic tumor growth and metastasis. These exciting data led us to expect that similar combination treatments will decrease the pro-metastatic effects of EtOH administration. We have observed rescued Golgi morphology in cells treated with both EtOH and HCQ, suggesting that Golgiphagy, blocked by HCQ, is involved in EtOH-induced Golgi disorganization. Additionally, HCQ restores the level of PM Integrin αv to that of control cells. We expect that combined HCQ treatment and ATF6 depletion will effectively attenuate the effects of EtOH on PCa aggressiveness and metastasis. Overall, these data will shed light on the previously unknown mechanism of alcohol-promoted prostate tumor growth and metastasis and provide a potentially effective therapeutic strategy.