PKM2 inhibitor shikonin suppresses TPA-induced mitochondrial malfunction and proliferation of skin epidermal JB6 cells.
PKM2 inhibitor shikonin suppresses TPA-induced mitochondrial malfunction and proliferation of skin epidermal JB6 cells.
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DOI：
10.1002/mc.21988
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发表时间：
2014-05
影响因子：
4.6
通讯作者：
Zhao Y
中科院分区：
文献类型：
--
作者：
Li W;Liu J;Zhao Y
化学预防已成为皮肤癌治疗的关键和有效的策略。利用人皮肤正常组织和肿瘤组织，我们发现丙酮酸激酶M2（PKM 2）在皮肤肿瘤组织中的表达和活性水平均高于正常组织，提示PKM 2作为一种重要的代谢酶，可能成为皮肤癌预防和/或治疗的靶点。紫草素是一种小分子活性化合物，已在人类癌症模型中作为抗癌候选药物进行了研究。然而，紫草素的作用机制和化学预防潜力尚不清楚。在此，我们使用皮肤表皮JB 6 P+细胞，并证明紫草素抑制肿瘤促进剂12-O-十四烷酰基佛波醇13-乙酸酯（TPA）诱导的肿瘤细胞转化和PKM 2激活的早期阶段的癌变。TPA处理抑制线粒体功能，表现为线粒体膜电位和线粒体呼吸降低，紫草素可使其恢复。我们还检测了乳酸作为糖酵解标志物的水平，紫草素抑制了肿瘤促进剂治疗引起的乳酸水平的增加。紫草素对细胞代谢的调节与G2-M期积累和Fra-1（皮肤肿瘤发生中激活蛋白1的主要亚基）下调有关。此外，我们还证明了一种能量传感器--AMP激活的蛋白激酶（AMPK），它被TPA灭活，紫草素可以逆转AMPK的活性。这些结果表明，紫草素承担人类皮肤癌中PKM 2上调，这可能是通过抑制致癌激活，PKM 2激活，线粒体功能障碍介导的化学预防潜力。
Chemoprevention has been a pivotal and effective strategy during the skin cancer treatment. Using human skin normal and tumor samples, we demonstrated that both the expression and activity levels of pyruvate kinase M2 (PKM2) were higher in skin tumor tissues than normal tissues, suggesting that PKM2, one of important metabolic enzyme, might serve as a target for skin cancer prevention and/or therapy. Shikonin, a small-molecule active chemical, has been studied as an anti-cancer drug candidate in human cancer models. However, the mechanism of action and the chemopreventive potential of shikonin are unclear. Herein, we used the skin epidermal JB6 P+ cells and demonstrated that shikonin suppressed the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA) induced neoplastic cell transformation and PKM2 activation in the early stage of carcinogenesis. Mitochondrial functions were inhibited by TPA treatment, as indicated by reduced mitochondrial membrane potential and mitochondrial respiration, which were restored by shikonin. We also examined the levels of lactate as a glycolysis marker, and shikonin suppressed its increase caused by tumor promoter treatment. Modulation of cell metabolism by shikonin was associated with G2–M phase accumulation, and Fra-1 (a major subunit of activator protein 1 in skin tumorigenesis) downregulation. In addition, we demonstrated that AMP-activated protein kinase (AMPK), an energy sensor, which is inactivated by TPA, shikonin could reverse AMPK activity. These results suggest that shikonin bears chemopreventive potential for human skin cancers in which PKM2 is upregulated, which might be mediated by inhibiting oncogenic activation, PKM2 activation, and mitochondrial dysfunction.