RESUMO
Objective:To investigate the effects of overexpression of long non-coding RNA maternally expressed gene 3 (LncRNA MEG3) on autophagy, apoptosis and mammalian rapamycin target protein (mTOR) pathway in pancreatic cancer cells (PANC1) .Methods:The pCMV-N-Flag-MEG3 expression plasmid was constructed and transfected into PANC1 cells. The expression of LncRNA MEG3 in hpde6c7 (normal pancreatic cells) group, PANC1 (blank control) , Vector (PANC1 cell transfected empty vector) group and MEG3 (PANC1 cell transfected with pCMV-N-Flag-MEG3 recombinant plasmid) group was detected by real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) ; methyl thiazolyl tetrazolium (MTT) , flow cytometry and monodansylcadaverin (MDC) staining were used to detect the effects of overexpression of LncRNA MEG3 on the proliferation, apoptosis and autophagy of PANC1 cells; Western blot was used to detect the effects of overexpression of LncRNA MEG3 on the expression levels of Bcl-2, Bax and Beclin-1 in PANC1 cells, and the phosphorylation levels of mTOR, ribosomal p70S6 kinase protein (SK61) and uclear initiation factor 4E binding protein 1 (4E-BP1) in mTOR pathway.Results:Compared with those in PANC1 group and Vector group, the expression level of LncRNA MEG3 (0.36±0.08 vs 0.35±0.11 vs 0.69±0.09) , proliferation inhibition rate (3.35%±0.12 vs 3.23%±0.09 vs 36.77%±0.13) , autophagy rate (29.32%±1.03 vs 26.73%±1.32 vs 57.76%±1.09) , apoptosis rate (9.85%±1.58 vs 9.73%±1.12 vs 35.89%±1.05) , expression levels of Bax (0.26±0.08 vs 0.29±0.05 vs 0.83±0.08) and Beclin 1 (0.15±0.06 vs 0.17±0.02 vs 0.61±0.03) of PANC1 cells in MEG3 group were significantly higher (all P<0.05) , and the expression level of Bcl-2 (0.79±0.12 vs 0.81±0.09 vs 0.30±0.03) and phosphorylation levels of mTOR (1.08±0.05 and 1.06±0.08 vs 0.37±0.10) , SK61 (1.12±0.06 and 1.11±0.09 vs 0.41±0.03) and 4E-BP1 (0.97±0.07 and 0.95±0.03 vs 0.39±0.05) in mTOR pathway were significantly lower (all P<0.05) . Conclusion:Overexpression of LncRNA MEG3 can inhibit the proliferation of PANC1 cells, promote apoptosis and formation of autophagic vesicles, which may be related to the blocking of mTOR pathway.