ITPR3 通过诱导 NF-ĸB/CD44 通路促进膀胱癌的生长、转移和干性。

BACKGROUND: Bladder carcinoma is one of the most common urological cancers. ITPR3, as a ubiquitous endoplasmic reticulum calcium channel protein, was reported to be involved in the development and progression of various types of cancer. However, the potential roles and molecular mechanism of ITPR3 in bladder cancer are still unclear. Herein, we elucidated a novel role of ITPR3 in regulating the proliferation, metastasis, and stemness of bladder cancer cells. METHODS: The expression of ITPR3 in bladder cancer was analyzed using public databases and bladder cancer tissue microarrays. To demonstrate the role of ITPR3 in regulating the NF-ĸB/CD44 pathway and the progression of bladder cancer, a series of molecular biology and biochemistry methods was performed on clinical tissues, along with in vivo and in vitro experiments. The methods used included western blot assay, quantitative RT-PCR assay, immunofluorescence assay, immunohistochemistry (IHC) assays, wound healing assay, Transwell assay, colony formation assay, tumorsphere formation assay, cell flow cytometry analysis, EdU assay, MTT assay, cell transfection, bisulfite sequencing PCR (BSP), a xenograft tumor model and a tail vein cancer metastasis model. RESULTS: Higher ITPR3 expression was found in bladder cancer tissues and bladder cancer cells compared with the corresponding normal peritumor tissues and SV-HUC-1 cells, which was attributed to demethylation in the ITPR3 promoter region. ITPR3 promoted the proliferation of bladder cancer by accelerating cell cycle transformation and promoted local invasion and distant metastasis by inducing epithelial-to-mesenchymal transition (EMT). Meanwhile, ITPR3 maintained the cancer stemness phenotype by regulating CD44 expression. NF-κB, which is upstream of CD44, also played a critical role in this process. CONCLUSIONS: Our study clarifies that ITPR3 serves as an oncogene in bladder cancer cells and represents a novel candidate for bladder cancer diagnosis and treatment.

背景：膀胱癌是最常见的泌尿系统癌症之一。ITPR3 作为一种普遍存在的内质网钙通道蛋白，被报道参与了多种类型癌症的发生和发展。然而，ITPR3 在膀胱癌中的潜在作用和分子机制尚不清楚。在此，我们阐明了 ITPR3 在调节膀胱癌细胞增殖、转移和干性中的新作用。

方法：使用公共数据库和膀胱癌组织微阵列分析 ITPR3 在膀胱癌中的表达。为了证明 ITPR3 在调节 NF-κB/CD44 通路和膀胱癌进展中的作用，我们在临床组织以及体内和体外实验中进行了一系列分子生物学和生物化学方法。所使用的方法包括 Western blot 分析、定量 RT-PCR 分析、免疫荧光分析、免疫组织化学（IHC）分析、划痕愈合试验、Transwell 试验、集落形成试验、肿瘤球形成试验、细胞流式细胞术分析、EdU 检测、MTT 检测、细胞转染、亚硫酸氢盐测序 PCR（BSP）、异种移植肿瘤模型和尾静脉癌症转移模型。

结果：与相应的正常肿瘤旁组织和 SV-HUC-1 细胞相比，膀胱癌组织和膀胱癌细胞中 ITPR3 的表达更高，这归因于 ITPR3 启动子区域的去甲基化。ITPR3 通过加速细胞周期转化促进膀胱癌的增殖，并通过诱导上皮间质转化（EMT）促进局部侵袭和远处转移。同时，ITPR3 通过调节 CD44 的表达维持癌症干细胞表型。NF-κB，作为 CD44 的上游，在这个过程中也起着关键作用。

结论：我们的研究阐明了 ITPR3 作为膀胱癌细胞中的癌基因的作用，并为膀胱癌的诊断和治疗提供了一个新的候选靶点。