From the Department of Radiology (D.E.J., S.M.T., K.A.B., B.E.K., J.L.A., M.R.C., D.A.W.) and Division of Gastroenterology and Hepatology (L.R.R.), Mayo Clinic School of Medicine, 200 First St SW, Rochester, MN 55905.
Radiology. 2019 Sep;292(3):752-759. doi: 10.1148/radiol.2019190115. Epub 2019 Jul 23.
BackgroundLocal recurrence following thermal ablation of hepatocellular carcinoma (HCC) larger than 2-3 cm remains a challenging clinical problem. Prior studies suggest that phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR)-dependent protein kinase B (AKT) signaling mediates HCC cell survival caused by moderate heat stress in vitro but these findings need in vivo validation.PurposeTo test the hypothesis that neoadjuvant inhibition of PI3K/mTOR/AKT signaling reduces HCC tumor growth in vivo after laser ablation and to evaluate the effects of moderate heat stress on molecular signaling and cellular function in HCC cells in vitroMaterials and MethodsHCC tumor-bearing mice were randomized to neoadjuvant PI3K/mTOR inhibitor (BEZ235) or control groups followed by an intentional partial laser ablation or sham ablation; there were at least nine mice per group. Postablation tumor growth was monitored up to 7 days. Tumor volumes were compared for drug or ablation groups by using two-way analysis of variance. N1S1 HCC cells pretreated with BEZ235 or control and subjected to moderate heat stress (45°C for 10 minutes) or control (37°C for 10 minutes) were analyzed by using mass spectrometry. Protein interaction networks were derived from protein expression analysis software, and cellular function activation state (Z-score) and fold-change in AKT phosphorylation were calculated.ResultsThere was a 37%-75% reduction in HCC tumor volume by day 7 after ablation in the BEZ235 plus ablation group (713 mm ± 417) compared with vehicle plus sham (1559 mm ± 552), vehicle plus ablation (1041 mm ± 591), and BEZ235 plus sham (1108 mm ± 523) groups ( < .001, = .04, and = .005, respectively). PI3K/mTOR inhibition prevented moderate heat stress-induced AKT signaling (Z-score, -0.2; < .001) and isoform-specific AKT phosphorylation compared with the vehicle plus heat stress group. PI3K/mTOR inhibition prevented moderate heat stress-induced global effects on HCC molecular signaling and cellular function, including decreased cell survival, growth, and proliferation (Z-score, -0.3 to -3.2; < .001) and increased apoptosis and cell death (Z-score, 0.4-1.1; < .001).ConclusionModerate heat stress induces PI3K/mTOR/AKT-dependent global effects on hepatocellular carcinoma (HCC) cell survival, function, and death. Neoadjuvant PI3K/mTOR/AKT inhibition reduces postablation HCC tumor growth.© RSNA, 2019See also the editorial by White in this issue.
背景 肝细胞癌（HCC）热消融后局部复发大于 2-3 cm 仍然是一个具有挑战性的临床问题。先前的研究表明，磷脂酰肌醇 3-激酶（PI3K）/哺乳动物雷帕霉素靶蛋白（mTOR）依赖性蛋白激酶 B（AKT）信号转导介导 HCC 细胞在体外中度热应激下的存活，但这些发现需要体内验证。目的 检测假说，即新辅助抑制 PI3K/mTOR/AKT 信号转导可减少激光消融后 HCC 肿瘤的生长，并评估中度热应激对 HCC 细胞体外分子信号和细胞功能的影响。材料与方法 HCC 荷瘤小鼠随机分为新辅助 PI3K/mTOR 抑制剂（BEZ235）或对照组，然后进行有意的部分激光消融或假消融；每组至少有 9 只小鼠。消融后监测肿瘤生长至 7 天。通过双因素方差分析比较药物或消融组的肿瘤体积。用 BEZ235 预处理的 N1S1 HCC 细胞或对照，然后进行中度热应激（45°C 10 分钟）或对照（37°C 10 分钟），并用质谱分析。从蛋白质表达分析软件中得出蛋白质相互作用网络，并计算 AKT 磷酸化的激活状态（Z 分数）和倍数变化。结果 与 vehicle plus sham（1559 mm ± 552）、vehicle plus ablation（1041 mm ± 591）和 BEZ235 plus sham（1108 mm ± 523）组相比，BEZ235 加消融组（713 mm ± 417）在消融后第 7 天 HCC 肿瘤体积减少 37%-75%（<.001、=.04 和 =.005）。PI3K/mTOR 抑制可预防中度热应激诱导的 AKT 信号转导（Z 分数，-0.2；<.001）和 AKT 磷酸化的同工型特异性，与 vehicle plus heat stress 组相比。PI3K/mTOR 抑制可预防中度热应激对 HCC 分子信号和细胞功能的全局影响，包括细胞存活、生长和增殖减少（Z 分数，-0.3 至-3.2；<.001）以及细胞凋亡和死亡增加（Z 分数，0.4-1.1；<.001）。结论 中度热应激诱导 PI3K/mTOR/AKT 依赖的 HCC 细胞存活、功能和死亡的全局效应。新辅助 PI3K/mTOR/AKT 抑制可减少消融后 HCC 肿瘤的生长。©RSNA，2019 也见本期 White 的社论。
