Mechanism of induction of cell differentiation and cell death by inhibitors against V-ATPase

在本研究项目中，我们研究了巴菲菌素、灵长菌素和去甲氧菌素等V-ATPase抑制剂抑制细胞生长、诱导细胞分化和诱导细胞凋亡的机制，以及这些抑制剂抑制质子转运的机制。我们发现(1)去甲氧菌素-B和-E都抑制溶酶体质子泵，但只有去铁菌素-E诱导PC12细胞的突起生长(NOG)。(2)鱼腥菌素通过H~+/Cl共转运蛋白的活性解偶联了多种质子泵活性，(3)去毛霉素B和-E都抑制了溶酶体质子泵，但只有去甲素-E诱导了神经突出生长(NOG)。如巴菲霉素A^&lt；(4)灵芝菌素诱导的NOG与巴福霉素诱导的NOG一样，既需要新的信使RNA的从头合成，也需要蛋白质的合成，对MAP、丝氨酸/苏氨酸磷酸酶、酪氨酸激酶、酪氨酸磷酸酶、钙化蛋白和磷脂酶A的抑制剂敏感；但对酪氨酸激酶和蛋白激酶A的抑制剂BE-18591耐药，它们也表现为H~+/Cu转运体，抑制猪胃质子泵，抑制胃壁细胞分泌Cid，抑制破骨细胞分化，抑制免疫淋巴细胞增殖，诱导神经节细胞和细胞凋亡，提示这些H~+/C_1转运体的不同生物学活性可能与它们的H~+/C_1转运体活性有关。这些结果表明，V-ATPase抑制剂对细胞内pH的影响不参与这些化合物表现出的生物活性的变化(包括NOG的诱导)。

In this research project, we have studied the machanism of (1) inhibition of cell growth, (2) induction of cell differentiation, and (3) induction of apoptosis, by V-ATPase inhibitors like bafilomycins, prodigiosins and destruxins, as well as the mechanims of inhibition of proton translocation by these inhibitors.We found (1) that both destrauxin-B and -E inhibited lysosomal proton pump, but only destruxin-E induced induced neurite out growth (NOG) of PC12 cells., (2) that prodigisins uncoupled various proton pump activities due to their H ^+ /Cl symport activity, (3) that prodigiosins, like bafilomycin A ^<1'> induced neurite out growth (NOG), and (4) that the prodigiosin-induced NOG, like bafolomycin-induced one, required de novo synthesis of new messenger RNA as well as protein synthesis, was sensitive to the inhibitors of MAP kinases, serine/threonine phosphatases, tyr-kinases, tyr-phosphatases, calmidulin and phospholipase A ^<2' > but resistant to inhibitors of trk tyrosine kinase and protein kinase A.BE-18591, a tambjamine group antibiotics, also behaved as H ^+ /CU symporters and inhibited hog gastric proton pump, inhibit *cid secretion by gastric parietal cells, inhibited osteoclast differentiation, suppressed proliferation of immune lymphocytes, and induced both NOG and apoptosis, suggesting that the variety of biological activities displayed by these H ^+ /C1 symporters may be due to their H ^+ /C1 symport activity. However, tetrapyrrole, another H ^+ /CV symporter, did not induced NOG.From these results, we conclud that the effect of V-ATPase inhibitors on the intracellular pH does not participate in the variety of biological activities (including induction of NOG) displayed by these compounds.