Department of Bioengineering, School of Engineering, The University of Tokyo, Tokyo, Japan.
Medical Device Development and Regulation Research Center, School of Engineering, The University of Tokyo, Tokyo, Japan.
Sci Rep. 2023 Apr 20;13(1):6493. doi: 10.1038/s41598-023-32444-4.
LI-cadherin is a member of the cadherin superfamily. LI-cadherin mediates Ca-dependent cell-cell adhesion through homodimerization. A previous study reported two single nucleotide polymorphisms (SNPs) in the LI-cadherin-coding gene (CDH17). These SNPs correspond to the amino acid changes of Lys115 to Glu and Glu739 to Ala. Patients with colorectal cancer carrying these SNPs are reported to have a higher risk of lymph node metastasis than patients without the SNPs. Although proteins associated with metastasis have been identified, the molecular mechanisms underlying the functions of these proteins remain unclear, making it difficult to develop effective strategies to prevent metastasis. In this study, we employed biochemical assays and molecular dynamics (MD) simulations to elucidate the molecular mechanisms by which the amino acid changes caused by the SNPs in the LI-cadherin-coding gene increase the risk of metastasis. Cell aggregation assays showed that the amino acid changes weakened the LI-cadherin-dependent cell-cell adhesion. In vitro assays demonstrated a decrease in homodimerization tendency and MD simulations suggested an alteration in the intramolecular hydrogen bond network by the mutation of Lys115. Taken together, our results indicate that the increased risk of lymph node metastasis is due to weakened cell-cell adhesion caused by the decrease in homodimerization tendency.
LI-钙黏蛋白是钙黏蛋白超家族的成员。LI-钙黏蛋白通过同源二聚化介导 Ca 依赖性细胞-细胞黏附。先前的研究报道了 LI-钙黏蛋白编码基因（CDH17）中的两个单核苷酸多态性（SNP）。这些 SNP 对应于赖氨酸 115 突变为谷氨酸和谷氨酸 739 突变为丙氨酸的氨基酸变化。携带这些 SNP 的结直肠癌患者比没有 SNP 的患者发生淋巴结转移的风险更高。尽管已经确定了与转移相关的蛋白质，但这些蛋白质功能的分子机制仍不清楚，这使得难以开发有效的预防转移的策略。在这项研究中，我们采用生化测定和分子动力学（MD）模拟来阐明 SNP 引起的 LI-钙黏蛋白编码基因中的氨基酸变化增加转移风险的分子机制。细胞聚集实验表明，氨基酸变化削弱了 LI-钙黏蛋白依赖性的细胞-细胞黏附。体外实验证明了同源二聚化趋势的降低，MD 模拟表明突变赖氨酸 115 改变了分子内氢键网络。综上所述，我们的研究结果表明，淋巴结转移风险增加是由于同源二聚化趋势降低导致细胞-细胞黏附减弱所致。
