Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China.
Department of General Surgery, Suzhou Dushu Lake Hospital (Dushu Lake Hospital Affiliated to Soochow University), Suzhou, China.
Mol Biotechnol. 2021 Sep;63(9):849-861. doi: 10.1007/s12033-021-00348-1. Epub 2021 Jun 7.
MiR-29a belongs to one of the subtypes of miRNAs known as non-coding single-stranded RNAs and is preferentially expressed in normal tissues. B7-H3, a member of the B7/CD28 immunoglobulin superfamily, was shown to be overexpressed in several solid malignant tumors, including colon cancer. In addition, it is associated with tumor progression and poor prognosis. We used immunohistochemical and Western blotting to assess B7-H3 protein expression levels in colon cancer and adjacent normal tissues and then compared their relationships with clinicopathological factors. Quantitative real-time reverse-transcription PCR was used to assess B7-H3 and miRNA-29a mRNA expression levels, and then their relationship and clinical significance were evaluated. In addition, colon cancer Caco-2 cells, which constitutively overexpress B7-H3, were transfected with lentivirus particles for miR-29a upregulation. Invasion and migration assays were carried out in vitro along with the establishment of a subcutaneous xenograft model in vivo to determine the role of miRNA-29a in colon cancer progression. The B7-H3 protein showed elevated expression in colon carcinoma and was relevant to TNM staging, lymph node metastasis, and reduced survival. Meanwhile, miR-29a was preferentially expressed in normal colon tissues, while B7-H3 transcript levels had no marked differences between tumor and normal tissue specimens. In vitro, miR-29a upregulation resulted in reduced B7-H3 expression. Furthermore, miR-29a upregulation reduced the invasive and migratory abilities of colon carcinoma cells. In animal models, upregulation of miR-29a slowed down the growth of subcutaneous xenotransplanted tumors and resulted in prolonged survival time. MiR-29a downregulates B7-H3 expression and accordingly inhibits colon cancer progression, invasion, and migration, indicating miR-29a and B7-H3 might represent novel molecular targets for advanced immunotherapy in colon cancer.
miR-29a 属于非编码单链 RNA 这一已知 miRNA 亚型之一，在正常组织中优先表达。B7-H3 是 B7/CD28 免疫球蛋白超家族的一个成员，在包括结肠癌在内的几种实体恶性肿瘤中显示过表达。此外，它与肿瘤进展和预后不良相关。我们使用免疫组织化学和 Western blot 检测结肠癌及相邻正常组织中 B7-H3 蛋白的表达水平，然后比较它们与临床病理因素的关系。我们使用实时定量逆转录 PCR 检测 B7-H3 和 miR-29a 的 mRNA 表达水平，然后评估它们之间的关系及其临床意义。此外，我们用慢病毒颗粒转染结肠癌细胞株 Caco-2，使其过表达 B7-H3，然后进行体外侵袭和迁移实验，并建立体内皮下移植瘤模型，以确定 miR-29a 在结肠癌进展中的作用。B7-H3 蛋白在结肠癌中表达升高，与 TNM 分期、淋巴结转移和生存率降低有关。同时，miR-29a 在正常结肠组织中优先表达，而 B7-H3 转录水平在肿瘤和正常组织标本之间无明显差异。体外实验中，miR-29a 的上调导致 B7-H3 表达减少。此外，miR-29a 的上调降低了结肠癌细胞的侵袭和迁移能力。在动物模型中，miR-29a 的上调减缓了皮下移植瘤的生长速度，延长了存活时间。miR-29a 下调 B7-H3 的表达，从而抑制结肠癌的进展、侵袭和迁移，表明 miR-29a 和 B7-H3 可能成为结肠癌晚期免疫治疗的新分子靶点。
