Disruption of TGF- signaling pathway is required to mediate effective killing of hepatocellular carcinoma by human iPSC-derived NK cells

Summary: Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. Transforming growth factor beta (TGF-β) is highly expressed in the liver tumor microenvironment and is known to inhibit immune cell activity. Here, we used human iPSCs to produce natural killer (NK) cells engineered to mediate improved anti-HCC activity. Specifically, we produced iPSC-NK cells with either knock out TGF-β receptor 2 (TGFBR2-KO) or expression of a dominant negative (DN) form of the TGF-β receptor 2 (TGFBR2-DN) combined with CARs that target either GPC3 or AFP. The TGFBR2-KO and TGFBR2-DN iPSC-NK cells are resistant to TGF-β inhibition and improved anti-HCC activity. However, expression of anti-HCC CARs on iPSC-NK cells did not lead to effective anti-HCC activity unless there was also inhibition of TGF- activity. Our findings demonstrate that TGF-β signaling blockade is required for effective NK cell function against HCC and potentially other malignancies which express high levels of TGF-β.

摘要：肝细胞癌（HCC）是最常见的原发性肝癌。转化生长因子β（TGF-β）在肝脏肿瘤微环境中高表达，且已知可抑制免疫细胞活性。本研究利用人类诱导多能干细胞（iPSCs）制备了经工程改造的自然杀伤（NK）细胞，以增强其抗HCC活性。具体而言，我们构建了两类iPSC-NK细胞：一类为敲除转化生长因子β受体2（TGFBR2-KO）的细胞，另一类为表达转化生长因子β受体2显性负效（DN）形式（TGFBR2-DN）的细胞，并联合搭载靶向磷脂酰肌醇蛋白聚糖3（GPC3）或甲胎蛋白（AFP）的嵌合抗原受体（CARs）。TGFBR2-KO与TGFBR2-DN型iPSC-NK细胞均可抵抗TGF-β的抑制作用，且抗HCC活性得到提升。然而，仅在iPSC-NK细胞上表达抗HCC CARs，并不会产生有效的抗HCC活性，除非同时阻断TGF-β的活性。本研究结果表明，阻断TGF-β信号通路是NK细胞发挥有效抗HCC及其他高表达TGF-β的恶性肿瘤免疫杀伤功能的必要条件。