[摘要] 目的：探讨miR-1297 对乳腺癌细胞恶性生物学行为的调控作用及其潜在机制。方法：选用2016 年5 月至2018 年5月乐山市人民医院甲乳外科手术切除的20 例乳腺癌组织和癌旁组织标本以及乳腺癌细胞系MCF-7、SW626、HCC1937 和人乳腺上皮细胞MCF-10A，用qPCR检测乳腺癌组织和细胞系中miR-1297 的表达水平。实验分为对照组、miR-1297 inhibitor 组、TET甲基胞嘧啶双加氧酶3（TET3）过表达组及同时过表达TET3 和miR-1297 组，用CCK-8、Transwell 实验检测MCF-7 细胞的增殖、迁移和侵袭能力，用WB检测MCF-7 细胞中TET3 和EMT相关蛋白（E-cadherin、N-cadherin 和vimentin）的表达水平。用双荧光素酶报告基因验证miR-1297 与TET3 的靶向关系。结果：miR-1297 在乳腺癌组织和细胞系中均高表达（P<0.01 或P<0.05）。敲降miR-1297 后，MCF-7 细胞的增殖、迁移、侵袭和EMT均明显受到抑制（P<0.05 或P<0.01）。转染pcDNA3.1-TET3 后，MCF-7 细胞TET3的表达水平显著上调（P<0.05）；同时过表达TET3 和miR-1297 能够逆转MCF-7 细胞中TET3 的表达水平及TET3 对MCF-7 细胞增殖、迁移、侵袭和EMT的抑制作用。双荧光素酶报告基因结果显示，miR-1297 靶向结合TET3 的3' UTR，miR-1297 靶向下调TET3 从而促进MCF-7 细胞的恶性生物学行为。结论：miR-1297 在乳腺癌组织和细胞中高表达，其通过靶向下调TET3 的表达水平促进MCF-7 细胞增殖、迁移、侵袭和EMT等恶性生物学行为。

[Abstract] Objective: To investigate the regulatory effect of miR-1297 on the malignant biological behaviors of breast cancer cells and its underlying mechanism. Methods: Twenty pairs of breast cancer tissues and para-cancer tissues resected at the Department of Thyroid and Breast Surgery of Leshan People ′ s Hospital from May 2016 to May 2018, as well as breast cancer cell lines MCF-7,SW626, HCC1937 and human breast epithelial MCF-10A cells were collected for this study. qPCR was performed to evaluate the expression of miR-1297 in breast cancer tissues and cell lines. The experimental cells were divided into control group, miR-1297 inhibitor group; TET3 over-expression group and simultaneous over-expression of TET3 and miR-1297 group. CCK-8 assay was used to detect the cell proliferation of MCF-7 cells; Transwell assay was carried out to detect the migration and invasion of MCF-7 cells; and WB was used to measure the expressions of TET3 and EMT related proteins (E-cadherin, N-cadherin and vimentin). Dual luciferase reporter gene assay was used to verify the relationship between miR-1297 and TET3. Results: miR-1297 was up-regulated in both breast cancer tissues and cell lines (P<0.01 or P<0.05). Knockdown of miR-1297 dramatically repressed the proliferation, migration, invasion and EMT of MCF-7 cells (P<0.01 or P<0.05). Over-expression of TET3 significantly up-regulated the expression of TET3 in MCF-7 cells (P<0.05). Simultaneous over-expression of TET3 and miR-1297 could reverse the expression level of TET3 in MCF-7 cells and the inhibitory effect of TET3 on the proliferation, migration, invasion and EMT of MCF-7 cells. Dual luciferase reporter gene assay results showed that miR-1297 targetedly bound to the 3' UTR of TET3. Further experiment results demonstrated that miR-1297 targetedly down-regulated TET3 and promoted the malignant biological behaviors of MCF-7 cells. Conclusion: miR-1297 is up-regulated in breast cancer tissues and cells; it promotes the malignant biological behaviors such as proliferation, migration, invasion and EMT through targetedly down-regulating the expression of TET3.

乐山市科技计划项目（No.15ZDYJ0032）