背景:CDH1和CTNNA1仍然是遗传性胃癌的主要基因。然而,他们只解释了一小部分怀疑遗传基础的胃癌病例。在这项研究中,我们旨在鉴定早发性胃癌患者(EOGC;<50岁)的新遗传基因.
方法:在20例EOGC患者中进行种系外显子组测序,并在152例患者的独立队列中通过基因面板测序复制相关发现,CTNND1是一个有趣的候选基因,因为它的蛋白质产物(p120ctn)直接与E-cadherin相互作用。我们通过基因编辑产生两个敲除CTNND1细胞模型并使用慢病毒递送系统引入检测到的遗传变异来进行功能表征。我们评估了β-catenin和E-cadherin水平,细胞脱离,以及E-cadherin定位和细胞间相互作用的球体模型。
结果:三种CTNND1种系变体[c.28_29delinsCT,p.(Ala10Leu);c.1105C>T,p.(Pro369Ser);c.1537A>G,p。(Asn513Asp)]在我们的EOGC队列中鉴定。编码CTNND1变体的细胞显示出改变的E-钙粘蛋白水平和细胞间相互作用。此外,p.(Pro369Ser)变体,位于E-cadherin/p120ctn结合域的关键区域,显示E-cadherin错误定位。
结论:CTNND1的缺陷可能通过改变E-cadherin和,因此,细胞间的相互作用。在本研究中,CTNND1种系变异解释了2%(3/172)的病例,尽管需要在更大的外部队列中进行进一步研究。
BACKGROUND: CDH1 and CTNNA1 remain as the main genes for hereditary gastric cancer. However, they only explain a small fraction of gastric cancer cases with suspected inherited basis. In this study, we aimed to identify new hereditary genes for early-onset gastric cancer patients (EOGC; < 50 years old).
METHODS: After germline exome sequencing in 20 EOGC patients and replication of relevant findings by gene-panel sequencing in an independent cohort of 152 patients, CTNND1 stood out as an interesting candidate gene, since its protein product (p120ctn) directly interacts with E-cadherin. We proceeded with functional characterization by generating two knockout CTNND1 cellular models by gene editing and introducing the detected genetic variants using a lentiviral delivery system. We assessed β-catenin and E-cadherin levels, cell detachment, as well as E-cadherin localization and cell-to-cell interaction by spheroid modeling.
RESULTS: Three CTNND1 germline variants [c.28_29delinsCT, p.(Ala10Leu); c.1105C > T, p.(Pro369Ser); c.1537A > G, p.(Asn513Asp)] were identified in our EOGC cohorts. Cells encoding CTNND1 variants displayed altered E-cadherin levels and intercellular interactions. In addition, the p.(Pro369Ser) variant, located in a key region in the E-cadherin/p120ctn binding domain, showed E-cadherin mislocalization.
CONCLUSIONS: Defects in CTNND1 could be involved in germline predisposition to gastric cancer by altering E-cadherin and, consequently, cell-to-cell interactions. In the present study, CTNND1 germline variants explained 2% (3/172) of the cases, although further studies in larger external cohorts are needed.