Tanaka Sachie, Miyazaki Hiroaki, Shiozaki Atsushi, Ichikawa Daisuke, Otsuji Eigo, Marunaka Yoshinori
Department of Molecular Cell Physiology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Cell Physiol Biochem. 2017;42(1):68-80. doi: 10.1159/000477116. Epub 2017 May 11.
BACKGROUND/AIMS: Our previous study revealed that cytosolic Cl- affected neurite elongation promoted via assembly of microtubule in rat pheochromocytoma PC12D cells and Cl--induced blockade of intrinsic GTPase enhanced tubulin polymerization in vitro. Paclitaxel (PTX) is a microtubule-targeted chemotherapeutic drug and stabilizes microtubules resulting in mainly blockade of mitosis at the metaphase-anaphase transition and induction of apoptosis. In the present study, we tried to clarify whether the cytosolic Cl- affected PTX ability to inhibit cell growth in the gastric cancer cell line, MKN28.
To clarify the cytosolic Cl- action on PTX-induced cell death and metaphase-anaphase transition in the gastric cancer cell line, MKN28 cell, and PTX-induced tubulin polymerization, we performed cell proliferation assay, cytosolic Cl- concentration measurement, immunofluorescence microscopy, and in vitro tubulin polymerization assay.
The decline of cytosolic Cl- weakened the cytotoxic effect of PTX on cell proliferation of MKN28 cells, which could pass through the metaphase-anaphase transition. Moreover, in vitro PTX-induced tubulin polymerization was diminished under the low Cl- condition.
Our results strongly suggest that the upregulation of cytosolic Cl- concentration would enhance the antitumor effect of PTX, and that the cytosolic Cl- would be one of the key targets for anti-cancer therapy.
背景/目的：我们之前的研究表明，胞质氯离子通过微管组装影响大鼠嗜铬细胞瘤PC12D细胞中神经突的伸长，并且氯离子诱导的内在GTP酶的阻断在体外增强了微管蛋白的聚合。紫杉醇（PTX）是一种靶向微管的化疗药物，可使微管稳定，主要导致有丝分裂在中期-后期转换时受阻并诱导细胞凋亡。在本研究中，我们试图阐明胞质氯离子是否会影响PTX对胃癌细胞系MKN28抑制细胞生长的能力。
为了阐明胞质氯离子对胃癌细胞系MKN28细胞中PTX诱导的细胞死亡和中期-后期转换以及PTX诱导的微管蛋白聚合的作用，我们进行了细胞增殖测定、胞质氯离子浓度测量、免疫荧光显微镜检查和体外微管蛋白聚合测定。
胞质氯离子浓度的降低减弱了PTX对MKN28细胞增殖的细胞毒性作用，这些细胞可以通过中期-后期转换。此外，在低氯离子条件下，体外PTX诱导的微管蛋白聚合减少。
我们的结果强烈表明，胞质氯离子浓度的上调会增强PTX的抗肿瘤作用，并且胞质氯离子可能是抗癌治疗的关键靶点之一。
