Abstract：
Pancreatic ductal adenocarcinoma (PDAC) remains the most lethal cancer type. PDAC is characterized by fibrotic, hypoxic, and presumably acidic tumor microenvironment (TME). Acidic TME is an important player in tumor development, progression, aggressiveness, and chemoresistance. The dysregulation of ductal ion transporters/channels might contribute to extracellular pH (pHe) acidification and PDAC progression. Our aim was to test whether H+/K+-ATPases and pH-sensitive K+ channels contribute to these processes and could be targeted by clinically approved drugs. We used human pancreatic cancer cells adapted to various pHe conditions and grown in monolayers and spheroids. First, we created cells expressing pHoran4 at the outer plasma membrane and showed that pantoprazole, the H+/K+-ATPase inhibitor, alkalinized pHe. Second, we used FluoVolt to monitor the membrane voltage (Vm) and showed that riluzole hyperpolarized Vm, most likely by opening of pH-sensitive K+ channels such as TREK-1. Third, we show that pantoprazole and riluzole inhibited cell proliferation and viability of monolayers and spheroids of cancer cells adapted to various pHe conditions. Most importantly, combination of the two drugs had significantly larger inhibitory effects on PDAC cell survival. We propose that co-targeting H+/K+-ATPases and pH-sensitive K+ channels by re-purposing of pantoprazole and riluzole could provide novel acidosis-targeted therapies of PDAC.
摘要：
胰腺导管腺癌(PDAC)仍然是最致命的癌症类型。PDAC的特点是纤维化，缺氧,和可能的酸性肿瘤微环境（TME）。酸性TME是肿瘤发展的重要参与者,programming,侵略性,和化学抗性。导管离子转运蛋白/通道的失调可能导致细胞外pH（pHe）酸化和PDAC进展。我们的目的是测试H+/K+-ATP酶和pH敏感的K+通道是否有助于这些过程，并且可以被临床批准的药物靶向。我们使用了适应各种pHe条件并在单层和球体中生长的人类胰腺癌细胞。首先,我们创造了在外质膜上表达pHoran4的细胞，并显示泮托拉唑，H+/K+-ATP酶抑制剂，碱化的PHE。第二,我们使用FluoVolt监测膜电压（Vm），并显示利鲁唑超极化Vm，最有可能通过打开pH敏感的K+通道，如TREK-1。第三，我们显示泮托拉唑和利鲁唑抑制适应各种pHe条件的癌细胞的单层和球体的细胞增殖和活力。最重要的是,两种药物联合使用对PDAC细胞存活有明显更大的抑制作用.我们建议通过重新使用泮托拉唑和利鲁唑来共同靶向H/K-ATPases和pH敏感的K通道可以提供PDAC的新型酸中毒靶向疗法。
