肿瘤的发生和进展是一个漫长而复杂的过程，受到内在因素（如基因突变）和外在因素（如环境污染）的共同影响。肝脏作为解毒器官，在人体对包括纳米材料（NMs）在内的各种环境污染物的暴露和反应中发挥着重要作用。肝细胞癌（HCC）是最常见的恶性肿瘤之一，仍然严重威胁人类健康。 NM 是否会促进肝癌进展仍然难以捉摸，评估长期暴露于亚毒性剂量的纳米颗粒 (NP) 仍然是一个挑战。在本研究中，我们重点研究了纳米氧化锌（nZnO）对人肝癌细胞HepG2恶性进展的促进作用，特别是经过理化转化的老化nZnO。在体外实验中，我们进行了集落形成效率、软琼脂集落对暴露于低剂量 nZnO (1.5 µg/mL) 3 或 4 个月的 HepG2 细胞进行形成和细胞迁移/侵袭测定。在体内实验中，我们将长期暴露于nZnO 4个月的HepG2细胞皮下接种到BALB/c无胸腺裸鼠中，观察肿瘤形成。施用ZnCl2以确定锌离子的作用。长期低剂量接触nZnO会显着加剧HCC细胞的恶性进展，而老化的nZnO可能会加剧恶性进展的严重程度。此外，通过转录组测序分析和体外细胞拯救实验，我们证明nZnO诱导HCC恶性进展的机制可能与细胞紧密连接的组成部分之一Claudin-2（CLDN2）的激活有关。其下游信号通路的失调。长期暴露新鲜和老化的nZnO通过上调CLDN2促进肝细胞癌恶性肿瘤。这项工作对癌症患者的影响可能是深远的，因为使用各种纳米产品和无意中接触经过环境改造的 NM 可能会在不知不觉中加速癌症的进展。© 2024 Yu 等人。

Tumor development and progression is a long and complex process influenced by a combination of intrinsic (eg, gene mutation) and extrinsic (eg, environmental pollution) factors. As a detoxification organ, the liver plays an important role in human exposure and response to various environmental pollutants including nanomaterials (NMs). Hepatocellular carcinoma (HCC) is one of the most common malignant tumors and remains a serious threat to human health. Whether NMs promote liver cancer progression remains elusive and assessing long-term exposure to subtoxic doses of nanoparticles (NPs) remains a challenge. In this study, we focused on the promotional effects of nano zinc oxide (nZnO) on the malignant progression of human HCC cells HepG2, especially aged nZnO that has undergone physicochemical transformation.In in vitro experiments, we performed colony forming efficiency, soft agar colony formation, and cell migration/invasion assays on HepG2 cells that had been exposed to a low dose of nZnO (1.5 μg/mL) for 3 or 4 months. In in vivo experiments, we subcutaneously inoculated HepG2 cells that had undergone long-term exposure to nZnO for 4 months into BALB/c athymic nude mice and observed tumor formation. ZnCl2 was administered to determine the role of zinc ions.Chronic low-dose exposure to nZnO significantly intensified the malignant progression of HCC cells, whereas aged nZnO may exacerbate the severity of malignant progression. Furthermore, through transcriptome sequencing analysis and in vitro cellular rescue experiments, we demonstrated that the mechanism of nZnO-induced malignant progression of HCC could be linked to the activation of Claudin-2 (CLDN2), one of the components of cellular tight junctions, and the dysregulation of its downstream signaling pathways.Long-term exposure of fresh and aged nZnO promotes hepatocellular carcinoma malignancy by up-regulating CLDN2. The implications of this work can be profound for cancer patients, as the use of various nanoproducts and unintentional exposure to environmentally transformed NMs may unknowingly hasten the progression of their cancers.© 2024 Yu et al.