Department of Human and Animal Physiology, Faculty of Biology, Ivan Franko National University of Lviv, 79005 Lviv, Ukraine.
Department of Therapy No. 1, Medical Diagnostic and Hematology and Transfusiology of Faculty of Postgraduate Education, Danylo Halytsky Lviv National Medical University, 79010 Lviv, Ukraine.
Int J Mol Sci. 2024 Jan 29;25(3):1657. doi: 10.3390/ijms25031657.
Bafilomycin A1 inhibits V-type H ATPases on the molecular level, which acidifies endo-lysosomes. The main objective of the study was to assess the effect of bafilomycin A1 on Ca content, NAADP-induced Ca release, and ATPase activity in rat hepatocytes and human colon cancer samples. Chlortetracycline (CTC) was used for a quantitative measure of stored calcium in permeabilized rat hepatocytes. ATPase activity was determined by orthophosphate content released after ATP hydrolysis in subcellular post-mitochondrial fraction obtained from rat liver as well as from patients' samples of colon mucosa and colorectal cancer samples. In rat hepatocytes, bafilomycin A1 decreased stored Ca and prevented the effect of NAADP on stored Ca. This effect was dependent on EGTA-Ca buffers in the medium. Bafilomycin A1 significantly increased the activity of Ca ATPases of endoplasmic reticulum (EPR), but not plasma membrane (PM) Ca ATPases in rat liver. Bafilomycin A1 also prevented the effect of NAADP on these pumps. In addition, bafilomycin A1 reduced Na/K ATPase activity and increased basal Mg ATPase activity in the subcellular fraction of rat liver. Concomitant administration of bafilomycin A1 and NAADP enhanced these effects. Bafilomycin A1 increased the activity of the Ca ATPase of EPR in the subcellular fraction of normal human colon mucosa and also in colon cancer tissue samples. In contrast, it decreased Ca ATPase PM activity in samples of normal human colon mucosa and caused no changes in colon cancer. Bafilomycin A1 decreased Na/K ATPase activity and increased basal Mg ATPase activity in normal colon mucosa samples and in human colon cancer samples. It can be concluded that bafilomycin A1 targets NAADP-sensitive acidic Ca stores, effectively modulates ATPase activity, and assumes the link between acidic stores and EPR. Bafilomycin A1 may be useful for cancer therapy.
巴弗洛霉素 A1 在分子水平上抑制 V 型 H+-ATP 酶，使内溶酶体酸化。本研究的主要目的是评估巴弗洛霉素 A1 对大鼠肝细胞和人结肠癌样本中 Ca 含量、NAADP 诱导的 Ca 释放和 ATP 酶活性的影响。金霉素 (CTC) 用于定量测量通透性大鼠肝细胞中储存的 Ca。ATP 酶活性通过从大鼠肝脏以及患者的结肠黏膜和结直肠癌细胞样本中获得的亚线粒体部分水解后释放的正磷酸盐含量来确定。在大鼠肝细胞中，巴弗洛霉素 A1 降低了储存的 Ca，并阻止了 NAADP 对储存的 Ca 的作用。这种作用依赖于培养基中的 EGTA-Ca 缓冲液。巴弗洛霉素 A1 显著增加了大鼠肝脏内质网 (EPR) 的 Ca ATP 酶活性，但不增加质膜 (PM) Ca ATP 酶活性。巴弗洛霉素 A1 还阻止了 NAADP 对这些泵的作用。此外，巴弗洛霉素 A1 降低了大鼠肝亚细胞部分的 Na/K ATP 酶活性并增加了基础 Mg ATP 酶活性。巴弗洛霉素 A1 和 NAADP 的同时给药增强了这些作用。巴弗洛霉素 A1 增加了正常人类结肠黏膜和结肠癌组织样本的 EPR 亚细胞部分的 Ca ATP 酶活性。相比之下，它降低了正常人类结肠黏膜样本的 Ca ATP 酶 PM 活性，但对结肠癌没有影响。巴弗洛霉素 A1 降低了正常结肠黏膜样本和人类结肠癌样本中的 Na/K ATP 酶活性并增加了基础 Mg ATP 酶活性。可以得出结论，巴弗洛霉素 A1 靶向 NAADP 敏感的酸性 Ca 储存库，有效调节 ATP 酶活性，并在酸性储存库和 EPR 之间建立联系。巴弗洛霉素 A1 可能对癌症治疗有用。
