Division of Molecular Pathology, Aichi Cancer Center Research Institute, Nagoya, Japan.
Departments of Pathology and Molecular Diagnostics, Aichi Cancer Center Hospital, Nagoya, Japan.
Gut. 2018 Jun;67(6):1103-1111. doi: 10.1136/gutjnl-2016-312927. Epub 2017 Mar 30.
Despite the recent advances in treatment of colon cancer, the prognosis is unfavourable for patients with distant metastases. The aim of this study was to identify targets for prevention and/or therapy of colon cancer metastasis.
CMT93 cells, a murine rectal cancer cell line with poor metastasising activity, were transduced with lentiviral shRNA library and transplanted into the rectum of syngeneic C57BL/6 mice. Genomic DNA was collected from metastatic lesions, and the integrated shRNA were retrieved by PCR for sequencing, followed by identification of the candidate genes targeted by the shRNA.
The genome-wide shRNA library screen identified () encoding a pre-mRNA splicing factor as a candidate metastasis suppressor gene. Knockdown of enhanced matrigel invasion activity of colon cancer cells in vitro, as well as their metastatic ability in vivo. An RNA-immunoprecipitation analysis showed Hnrnpll-binding to pre-mRNAs, and the level of () a poor prognosis marker of colorectal cancer, was increased by knocking down . A neutralising Cd44v6 antibody suppressed the matrigel invasion ability induced by knockdown. HNRNPLL expression was downregulated when colon cancer cells were induced to undergo epithelial-mesenchymal transition (EMT). Immunohistochemistry of clinical samples indicated that colorectal cancer cells with low E-cadherin expression at the invasion front exhibited decreased HNRNPLL expression.
HNRNPLL is a novel metastasis suppressor of colorectal cancer, and modulates alternative splicing of during EMT.
尽管结肠癌的治疗最近取得了进展，但对于远处转移的患者，预后仍不佳。本研究旨在确定预防和/或治疗结肠癌转移的靶点。
CMT93 细胞是一种具有低转移活性的鼠直肠癌细胞系，用慢病毒 shRNA 文库转导并移植到同基因 C57BL/6 小鼠的直肠中。从转移病灶中收集基因组 DNA，并通过 PCR 回收整合的 shRNA 进行测序，然后鉴定被 shRNA 靶向的候选基因。
全基因组 shRNA 文库筛选鉴定出编码剪接因子前体的 （）作为候选转移抑制基因。 （）的敲低增强了体外结肠癌细胞的基质胶侵袭活性以及体内的转移能力。RNA-免疫沉淀分析表明 Hnrnpll 与 （）的前体 RNA 结合，而作为结直肠癌预后不良标志物的 （）水平则因 （）的敲低而升高。一种中和性 Cd44v6 抗体抑制了由 （）敲低诱导的基质胶侵袭能力。当结肠癌细胞被诱导发生上皮-间充质转化（EMT）时，HNRNPLL 的表达下调。免疫组织化学分析临床样本表明，在侵袭前沿 E-钙黏蛋白表达较低的结直肠癌细胞中，HNRNPLL 的表达减少。
HNRNPLL 是结直肠癌的一种新型转移抑制因子，并且在 EMT 过程中调节 （）的可变剪接。
