Expression of LncRNA MALAT1 in Retinoblastoma Tissue and Its Effect on Biological Behavior of Y79 Cells by Targeting miR-145-5p/SOX9 Axis

YAN Xiaoxiao¹, YIN Shuanghui², LI Xiaojing³, SUN Min⁴*

(¹Department of Ophthalmology, Handan Central Hospital, Handan 056001, China; ²Department of Internal Medicine, Handan Hangang Hospital, Handan 056001, China; ³Department of Orthopedics, the Second Affiliated Hospital of Xingtai Medical College, Xingtai 054002, China; ⁴Ophthalmology Department, General Hospital of North China Petroleum Administration Bureau, Cangzhou 062552, China)

Abstract:

The aim of this study was to investigate the expression of LncRNA (long non-coding RNA) MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) in RB (retinoblastoma) tissues, and its effect on the biological behavior of Y79 cells by targeting microRNA-145-5p/SOX9 (sex determining region Y box protein 9) axis. qRT-PCR was applied to detect the relative expression levels of MALAT1, miR-145-5p, and SOX9 mRNA in RB tissue and Y79 cells. FISH (fluorescence in situ hybridization) experiment and double luciferase reporter gene experiment were applied to verify the targeting relationship between MALAT1, SOX9 and miR-145-5p. Y79 cells were grouped into sh-NC group, sh-MALAT1 group, sh-MALAT1+miR-NC group, sh-MALAT1+miR-145-5p inhibitor group, mimics-NC group, miR-145-5p mimics group, miR-145-5p mimics+pcDNA group, and miR-145-5p mimics+SOX9 group. MTT method and cell cloning experiment were applied to detect cell proliferation. Flow cytometry was applied to detect cell apoptosis. Transwell cells were applied to detect cell migration and invasion. Western blot was applied to detect the expression of SOX9, Ki67, MMP9, Bcl-2, and Cleaved Caspase-3 proteins. In vivo tumor formation experiment was applied to verify the effect of MALAT1 on RB tumors. The results showed that MALAT1 was highly expressed in RB tissue and Y79 cells (P<0.05). FISH experiment and double luciferase reporter gene experiment confirmed that MALAT1, SOX9 and miR-145-5p had a targeting relationship. Silencing MALAT1 or overexpressing miR-145-5p was able to inhibit the proliferation, migration, and invasion of Y79 cells, and promote apoptosis (P<0.05). Inhibiting miR145-5p or overexpressing SOX9 was able to reverse the effects of silencing MALAT1 or overexpressing miR145-5p on the biological behavior of Y79 cells (P<0.05). In vivo experiments showed that inhibiting the expression of MALAT1 was able to obviously inhibit the growth of transplanted tumors in mice (P<0.05). MALAT1 is highly expressed in RB tissue and Y79 cells, and MALAT1 can participate in the biological behavior of Y79 cells by regulating the miR-145-5p/SOX9 signaling axis.

CSTR: 32200.14.cjcb.2023.10.0004