DataSheet_1_Ketogenic diet enhances the anti-cancer effects of PD-L1 blockade in renal cell carcinoma.pdf

IntroductionClear cell renal cell carcinoma (ccRCC) is characterized by a predominant metabolic reprogramming triggering energy production by anaerobic glycolysis at the expense of oxydative phosphorylation. Ketogenic diet (KD), which consists of high fat and low carbohydrate intake, could bring required energy substrates to healthy cells while depriving tumor cells of glucose. Our objective was to evaluate the effect of KD on renal cancer cell tumor metabolism and growth proliferation.
MethodsGrowth cell proliferation and mitochondrial metabolism of ACHN and Renca renal carcinoma cells were evaluated under ketone bodies (KB) exposure. In vivo studies were performed with mice (nude or Balb/c) receiving a xenograft of ACHN cells or Renca cells, respectively, and were then split into 2 feeding groups, fed either with standard diet or a 2:1 KD ad libitum. To test the effect of KD associated to immunotherapy, Balb/c mice were treated with anti-PDL1 mAb. Tumor growth was monitored.
ResultsIn vitro, KB exposure was associated with a significant reduction of ACHN and Renca cell proliferation and viability, while increasing mitochondrial metabolism. In mice, KD was associated with tumor growth reduction and PDL-1 gene expression up-regulation. In Balb/c mice adjuvant KD was associated to a better response to anti-PDL-1 mAb treatment.
ConclusionKB reduced the renal tumor cell growth proliferation and improved mitochondrial respiration and biogenesis. KD also slowed down tumor growth of ACHN and Renca in vivo. We observed that PDL-1 was significantly overexpressed in tumor in mice under KD. Response to anti-PDL-1 mAb was improved in mice under KD. Further studies are needed to confirm the therapeutic benefit of adjuvant KD combined with immunotherapy in patients with kidney cancer.

引言
透明细胞肾细胞癌（clear cell renal cell carcinoma，ccRCC）以显著的代谢重编程为特征，该重编程通过以氧化磷酸化为代价，激活无氧糖酵解以产生能量。生酮饮食（ketogenic diet，KD）指高脂低碳水化合物摄入的饮食模式，可为健康细胞提供所需能量底物，同时剥夺肿瘤细胞的葡萄糖供给。本研究旨在评估生酮饮食对肾癌细胞肿瘤代谢与增殖生长的影响。

方法
本研究检测了暴露于酮体（ketone bodies，KB）环境下，ACHN与Renca肾癌细胞的增殖活力及线粒体代谢水平。体内实验分别采用接种ACHN细胞异种移植物的裸鼠，以及接种Renca细胞异种移植物的Balb/c小鼠，将其分为2个喂食组，分别自由进食标准饮食或2:1比例的生酮饮食。为探究生酮饮食联合免疫治疗的效果，对Balb/c小鼠给予抗PD-L1单克隆抗体（anti-PDL1 mAb）处理，并监测肿瘤生长情况。

结果
体外实验显示，酮体暴露可显著降低ACHN与Renca细胞的增殖活力与存活率，同时提升其线粒体代谢水平。小鼠实验中，生酮饮食可抑制肿瘤生长，并上调PD-L1基因的表达。在Balb/c小鼠中，辅助性生酮饮食可增强其对抗PD-L1单克隆抗体治疗的响应。

结论
酮体可抑制肾肿瘤细胞的增殖生长，并改善线粒体呼吸与生物发生过程。生酮饮食同样可在体内延缓ACHN与Renca细胞的肿瘤生长。我们观察到，进食生酮饮食的小鼠肿瘤组织中PD-L1呈现显著高表达。进食生酮饮食的小鼠对抗PD-L1单克隆抗体治疗的响应得到提升。未来仍需开展进一步研究，以证实辅助性生酮饮食联合免疫治疗在肾癌患者中的治疗获益。