Granja Sara, Marchiq Ibtissam, Le Floch Renaud, Moura Conceição Souto, Baltazar Fátima, Pouysségur Jacques
Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.
ICVS/3B's-PT Government Associate Laboratory, Braga/ Guimarães, Portugal.
Oncotarget. 2015 Mar 30;6(9):6708-21. doi: 10.18632/oncotarget.2862.
Most cancers rely on aerobic glycolysis to generate energy and metabolic intermediates. To maintain a high glycolytic rate, cells must efficiently export lactic acid through the proton-coupled monocarboxylate transporters (MCT1/4). These transporters require a chaperone, CD147/BASIGIN (BSG) for trafficking to the plasma membrane and function.To validate the key role of these transporters in lung cancer, we first analysed the expression of MCT1/4 and BSG in 50 non-small lung cancer (NSCLC) cases. These proteins were specifically upregulated in tumour tissues. We then disrupted BSG in three NSCLC cell lines (A549, H1975 and H292) via 'Zinc-Finger Nucleases'. The three homozygous BSG-/- cell lines displayed a low MCT activity (10- to 5-fold reduction, for MCT1 and MCT4, respectively) compared to wild-type cells. Consequently, the rate of glycolysis, compared to the wild-type counterpart, was reduced by 2.0- to 3.5-fold, whereas the rate of respiration was stimulated in BSG-/- cell lines. Both wild-type and BSG-null cells were extremely sensitive to the mitochondria inhibitor metformin/phenformin in normoxia. However, only BSG-null cells, independently of their LKB1 status, remained sensitive to biguanides in hypoxia in vitro and tumour growth in nude mice. Our results demonstrate that inhibiting glycolysis by targeting lactic acid export sensitizes NSCLC to phenformin.
大多数癌症依赖有氧糖酵解来产生能量和代谢中间体。为了维持较高的糖酵解速率，细胞必须通过质子偶联单羧酸转运体（MCT1/4）有效地输出乳酸。这些转运体需要一种伴侣蛋白CD147/基底膜蛋白（BSG）来运输到质膜并发挥功能。为了验证这些转运体在肺癌中的关键作用，我们首先分析了50例非小细胞肺癌（NSCLC）病例中MCT1/4和BSG的表达。这些蛋白在肿瘤组织中特异性上调。然后，我们通过“锌指核酸酶”在三种NSCLC细胞系（A549、H1975和H292）中破坏BSG。与野生型细胞相比，三种纯合BSG-/-细胞系的MCT活性较低（MCT1和MCT4分别降低10至5倍）。因此，与野生型细胞相比，糖酵解速率降低了2.0至3.5倍，而BSG-/-细胞系中的呼吸速率受到刺激。在常氧条件下，野生型和BSG缺失的细胞对线粒体抑制剂二甲双胍/苯乙双胍都极为敏感。然而，仅BSG缺失的细胞，无论其LKB1状态如何，在体外低氧条件下对双胍类药物仍敏感，并且在裸鼠体内对肿瘤生长也敏感。我们的结果表明，通过靶向乳酸输出抑制糖酵解可使NSCLC对苯乙双胍敏感。
