Supplementary Material for: Downregulation of ZNF395 Drives Progression of Pancreatic Ductal Adenocarcinoma through Enhancement of Growth Potential

<b><i>Background:</i></b> Progression of pancreatic intraepithelial neoplasia (PanIN) to invasive carcinoma is a critical factor impacting the prognosis of patients with pancreatic tumors. However, the molecular mechanisms involved are not fully understood. We have reported that the process frequently involves loss of chromosome 8p, causing downregulation of DUSP4, thus conferring invasive ability on cancer cells. Here, we focus on ZNF395, whose expression was also found to be decreased by 8p loss and was predicted to be a growth suppressor gene. <b><i>Methods:</i></b> Pancreatic cancer cell lines inducibly expressing ZNF395 were established to assess the functional significance of ZNF395 in pancreatic carcinogenesis. Immunohistochemistry was also performed to analyze the expression levels of ZNF395 in pancreatic cancer tissues. <b><i>Results:</i></b> Induction of ZNF395 in pancreatic cancer cells resulted in marked activation of JNK and suppression of their proliferation through a delay in cell cycle progression. Immunohistochemistry revealed that ZNF395 was expressed ubiquitously in both normal pancreatic ducts and PanINs but was significantly reduced in invasive cancers, especially those showing poor differentiation. <b><i>Conclusion:</i></b> ZNF395 acts as a novel tumor suppressor gene. Its downregulation caused by 8p loss in intraepithelial cells accelerates their proliferation through dysregulation of the cell cycle, leading to progression to invasive cancer.

<b><i>研究背景：</i></b> 胰腺上皮内瘤变（Pancreatic intraepithelial neoplasia, PanIN）进展为浸润性癌是影响胰腺肿瘤患者预后的关键因素，但其潜在分子机制尚未完全阐明。本团队此前的研究表明，该进程常伴随8号染色体短臂（8p）缺失，导致双特异性磷酸酶4（DUSP4）表达下调，进而赋予癌细胞侵袭能力。本研究聚焦于ZNF395，该基因的表达同样因8p缺失而降低，且被预测为生长抑制基因。<b><i>实验方法：</i></b> 本研究构建了可诱导表达ZNF395的胰腺癌细胞系，以评估ZNF395在胰腺癌变过程中的功能意义；同时采用免疫组织化学（Immunohistochemistry）技术分析胰腺癌组织中ZNF395的表达水平。<b><i>实验结果：</i></b> 在胰腺癌细胞中诱导ZNF395表达后，可显著激活c-Jun氨基末端激酶（JNK），并通过延缓细胞周期进程抑制癌细胞增殖。免疫组织化学检测结果显示，ZNF395在正常胰腺导管及PanIN中广泛表达，但在浸润性癌组织中表达显著下调，尤其是低分化癌组织。<b><i>研究结论：</i></b> ZNF395是一种新型肿瘤抑制基因。上皮细胞中8p缺失导致的ZNF395表达下调，会通过扰乱细胞周期进程促进细胞增殖，进而加速上皮内瘤变进展为浸润性癌。