Transcriptome analysis of PDAC cells induced primary cilia and control

Primary cilia (PC) are non-motile cellular structure extending from the apical membrane of epithelial cells. They are central hubs for numerous signalling pathways implicated in various biological processes and are significantly decreased in various tumors, including pancreatic ductal adenocarcinoma. However, research on PC in oncology is limited, and the roles of their absence and presence in cancer cells are poorly understood. We analysed the effect of the induction of primary cilia in pancreatic ductal adenocarcinoma (PDAC) cells by RNA sequencing.Total RNA was extracted from control (n=6) and primary cilia induced (n=6) PDAC cells.A mechanistic study indicated that inversin, a protein located in PC, increased the expression and secretion of IL-1a by regulating the noncanonical Wnt/planar cell polarity pathway (Wnt/PCP). In conclusion, our study revealed the specific mechanism by which PC promote cell metastasis of tumor through IL-1a, highlighting the need for further investigation of PC as a potential therapeutic target for pancreatic ductal adenocarcinoma. Overall design: We selected four PDAC cell lines derived from human pancreatic duct cells and induced them to grow primary cilia (PC) through serum starvation. These cilia were labeled red rods using acetylated a-tubulin antibody. Statistically, different cells were found to have varying degrees of PC increase after induction (48 h serum starvation). Under normal culture conditions, PC was present in 7%, 6.5%, 5%, and 11% of the CFPAC-1, CAPAN-1, BxPC-3, and PANC-1 cell lines, respectively. The frequency increased to 39%, 18%, 78%, and 64% after cilia induction. To explore the function of PC during tumorigenesis and development, we performed RNA-seq on CFPAC-1 and BxPC-3 cells induced PC.

初级纤毛（Primary cilia, PC）是一种从上皮细胞顶膜伸出的非运动性细胞结构。其作为诸多参与多种生物学过程的信号通路的核心枢纽，且在包括胰腺导管腺癌（pancreatic ductal adenocarcinoma, PDAC）在内的多种肿瘤中显著减少。然而，肿瘤学领域针对PC的研究仍较为有限，人们对其在癌细胞中存在与缺失所发挥的作用尚知之甚少。本研究通过RNA测序（RNA sequencing, RNA-seq）分析了初级纤毛诱导对胰腺导管腺癌（PDAC）细胞的影响。我们从对照组（n=6）与初级纤毛诱导组（n=6）的PDAC细胞中提取了总RNA。机制研究表明，定位于PC的向位素（inversin）可通过调控非经典Wnt/平面细胞极性通路（Wnt/PCP），促进IL-1α的表达与分泌。综上，本研究揭示了PC通过IL-1α促进肿瘤细胞转移的具体机制，凸显了将PC作为胰腺导管腺癌潜在治疗靶点开展进一步研究的必要性。

实验整体设计：我们选取了4株源自人胰腺导管细胞的PDAC细胞系，通过血清饥饿法诱导其生成初级纤毛（PC）。我们采用乙酰化α-微管蛋白抗体将这些纤毛标记为红色杆状结构。经统计分析，在经过48小时血清饥饿诱导后，不同细胞系的PC阳性率均呈现不同程度的升高。在常规培养条件下，CFPAC-1、CAPAN-1、BxPC-3与PANC-1细胞系的PC阳性率分别为7%、6.5%、5%及11%。经纤毛诱导后，上述细胞系的PC阳性率分别升至39%、18%、78%及64%。为探究PC在肿瘤发生与发展过程中的功能，我们对诱导生成PC的CFPAC-1与BxPC-3细胞开展了RNA测序（RNA-seq）。