Knockdown Of LncRNA SNHG16 Suppresses Multiple Myeloma Cell Proliferation By Sponging MiR-342-3p

Objective Multiple myeloma(MM)is one of the most common hematological tumors.With rapidly aging population in China,the incidence of MM is increasing and the age of onset is becoming younger.The etiology of MM is complex and the potential molecular mechanisms are not clear,so that MM is still incurable.Studies have confirmed that long non-coding RNA(lncRNA)is involved in the regulation of many biological processes.It has been reported that lncRNA SNHG16 is abnormally expressed as a carcinogenic gene in a variety of tumor tissues and also involved in the proliferation,migration and invasion of cancer.However,the important role of lncRNA SNHG16 in MM and its potential molecular mechanisms are still largely unknown.This study is supposed to determine the expression of lncRNA SNHG 16 in clinical samples and cells of MM,and to confirm the effects of lncRNA SNHG 16 on the proliferation,cycle and apoptosis of MM cells.Exploring its possible molecular mechanisms could provide theoretical basis for lncRNA SNHG 16 as a new tumor molecular marker and theraputic target of MM,Methods(1)The fresh bone marrow samples of 20 MM patients and 15 healthy volunteers were collected from the Department of Hematology,affiliated Hospital of Nantong University from June 2018 to January 2019.The relative expression levels of lncRNA SNHG 16 in the samples and cells were detected by real-time fluorescence quantitative PCR(qRT-PCR).(2)The relative expression of lncRNA SNHG 16 in RPMI-8226,NCI-H929 cells and peripheral blood mononuclear cells(PBMC)was detected by qRT-PCR.(3)The small interfering RNA(siRNA)sequence was designed to specifically interfere with the expression of lncRNA SNHG 16.After Si-SNHG16 gene transient transfection into RPMI-8226 and NCI-H929 cells,the interference efficiency was detected.(4)The tests of MTS assay,flow cytometry and Western blot assay were used to detect the effects of si-SNHG16 on cell proliferation,cell cycle,apoptosis and the expression of related proteins in RPMI-8226 and NCI-H929 cells.(5)The luciferase reporter gene assay was used to detect the interaction between lncRNA SNHG16 and miR-342-3p.(6)The effects of lncRNA SNHG16 and miR-342-3p on the proliferation,cycle,apoptosis and related protein expression in RPMI-8226 and NCI-H929 cells were verified by miR-342-3p overexpression and miR-342-3p silencing experiments.Results(1)Compared with healthy volunteers,the relative expression level of lncRNA SNHG16 in bone marrow samples of MM patients was significantly up-regulated.(2)Compared with PBMC,the relative expression level of lncRNA SNHG16 in RPMI-8226 and NCI-H929 cells was significantly up-regulated.(3)The interference with lncRNA SNHG16 expression could significantly inhibit the proliferation,increase the proportion of cells in G1 phase,decrease the proportion of cells in S phase,and promote cell apoptosis in RPMI-8226 and NCI-H929 cells.(4)Interfering with the expression of lncRNA SNHG16 could significantly promote the expression of cleaved-Caspase-3,cleaved-Caspase-9,Foxo3a and Bax,and inhibit the expression of CCND1 gene,Bcl-2,Cyclin D1,PI3K and p-AKT in RPMI-8226 and NCI-H929 cells.(5)LncRNA SNHG16 can bind to miR-342-3p directly.Furthermore,there is a negative correlation between the expression of miR-342-3p and lncRNA SNHG16 in clinical samples and cells of MM.(6)The overexpression of miR-342-3p could significantly inhibit the proliferation,increase the proportion of cells in G1 phase,decrease the proportion of cells in S phase,promote apoptosis,promote the expression of cleaved-Caspase-3,cleaved-Caspase-9,Foxo3a and Bax,and inhibit the expression of Bcl-2,Cyclin D1,PI3K and p-AKT in RPMI-8226 and NCI-H929 cells.(7)Interfering with lncRNA SNHG16 expression and silencing miR-342-3p expression could significantly promote the proliferation,decrease the proportion of cells in G1 phase,increase the proportion of cells in S phase,inhibit apoptosis,inhibit the expression of cleaved-Caspase-3,cleaved-Caspase-9,Foxo3a and Bax,and promote the expression of Bcl-2,Cyclin D1,PI3K and p-AKT in RPMI-8226 and NCI-H929 cells.Conclusions(1)The relative expression level of lncRNA SNHG16 in bone marrow samples of MM patients and MM cell lines was significantly up-regulated.(2)The interference with lncRNA SNHG16 expression could significantly inhibit the proliferation of MM cells,induce cell arrest in G1 phase,promote apoptosis,and induce cell cycle,apoptosis and expression of proteins or genes related to PI3K/AKT pathway.(3)LncRNA SNHG16 can be directly combined with miR-342-3p.Interfering with the expression of lncRNA SNHG16 inhibits the proliferation of MM cells and promotes apoptosis by binding to miR-342-3p.(4)The effect of miR-342-3p overexpression was similar to that of interfering with lncRNA SNHG16 expression on MM cell proliferation,while silencing miR-342-3p expression could reverse the effect of interfering lncRNA SNHG16 expression on MM cell proliferation.