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【Objective】 To explore the effects of long non-coding RNA maternally expressed gene 3 (lncRNA MEG3) on the invasion and migration of prostate cancer cells (PC3 cells) by regulating microRNA-181b-5p (miR-181b-5p)/tissue inhibitor of metalloproteinase 3 (TIMP3). 【Methods】 The prostate cancer tissues and adjacent tissues were collected from 20 prostate cancer patients treated in our hospital during Dec.2020 and Dec.2021. The expressions of MEG3 and miR-181b-5p in tissues were detected with quantitative real-time PCR (qRT-PCR). P3 cells were randomly divided into control group (untreated), pcDNA3.1-NC (transfected with pcDNA3.1-NC), pcDNA3.1-MEG3 group (transfected with pcDNA3.1-MEG), pcDNA3.1-MEG3+miR-NC group (pcDNA3.1-MEG3 co-transfected with miR-NC), pcDNA3.1-MEG3+miR-181b-5p mimic group (pcDNA3.1-MEG3 co-transfected with miR-181b-5p mimic). The expressions of MEG3 and miR-181b-5p in PC3 cells were detected with qRT-PCR. The cell viability, invasion and migration ability were determined with MTT assay, Transwell assay and scratch assay. The protein expressions of TIMP3, matrix metalloproteinase (MMP)9 and MMP2 in PC3 cells were detected with Western blot. The targeting relationship of MEG3, miR-181b-5p and TIMP3 was analyzed with dual luciferase assay. 【Results】 The expressions of MEG3 in prostate cancer tissues ( 0.37±0.05 vs. 1.00±0.04) and cells (0.31±0.06 vs. 1.00±0.01) were significantly decreased (P<0.05). Compared with the control group, the pcDNA3.1-MEG3 group had significantly decreased expression of miR-181b-5p (0.26±0.04 vs.1.00±0.02 ), cell survival rate (53.60±5.22 vs.100.00±0.00), number of invasive cells (62.33±9.85 vs.162.34±21.30), cell migration rate (32.85±3.80 vs.75.22±5.96), expressions of MMP9 (0.61±0.08 vs.1.62±0.23) and MMP2 (0.73±0.10 vs.1.20±0.16), but significantly higher expressions of MEG3 (2.31±0.36 vs. 1.00±0.01) and TIMP3 (1.32±0.24 vs. 0.53±0.08) (P<0.05). Overexpression of miR-181b-5p reversed the above changes (P<0.05). MiR-181b-5p had a targeting relationship with MEG3 and TIMP3. 【Conclusion】 Overexpression of lncRNA MEG3 can inhibit miR-181b-5p to promote the expression of TIMP3, thereby inhibiting invasion and migration of PC3 cells.
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Objective To investigate the role of LncRNAs-MEG3 in the carcinogenesis and progression of nasopharyngeal carcinoma (NPC) and the possible molecular mechanism. Methods qRT-PCR was used to detect the content of MEG3 and miR-543 in NPC cells. Luciferase reporter method was used to study the relation between MEG3 and miR-543, and the changes of cell proliferation and apoptosis induced by MEG3 or KLF4 were analyzed. Western blot was used to detect the expression of KLF4, Bcl-2 and Bax proteins. Results Compared with the control group, the expression of miR-543 in NPC cell line was significantly increased (P < 0.05), while the expression of MEG3 was decreased (P < 0.05). Luciferase report and Western blot showed that MEG3 could regulate the expression of KLF4 by adsorbing miR-543 to inhibit cell proliferation, promote cell apoptosis and affect the expression levels of Bcl-2 and Bax proteins. Conclusion LncRNA-MEG3 could regulate the expression of KLF4 by adsorbing miR-543 and then plays a role in inhibiting the occurrence and development of NPC. It may be a new biomarker for NPC targeted therapy.
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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.
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As long non-coding RNA (LncRNA) research boom,Maternally Expressed Gene 3(MEG3) as LncRNA family is also a widespread concern.MEG3 not been studied in benign disease,and malignant disease more and more in-depth research.MEG3 because of the uniqueness of the tumor suppressor much attention in cancer research,but its specific mechanism of action of tumor suppressor and associated pathways have not been yet entirely clear,remains to be further research and clarify.This article will be now anticancer activity MEG3 and related Pathway summarized.
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Objective:To investigate the expression of maternally expressed gene 3 (MEG3), a long non-coding RNA gene, in gastric can-cer tissues;determine the relationship of MEG3 with the prognosis of gastric cancer;and explore the relationship between MEG3 and apoptosis-associated protein P53 as well as murine double minute 2 (MDM2). Methods:Fifty-five consecutive patients with gastric cancer admitted to Qingdao Municipal Hospital for surgical treatment from September 2012 to June 2013 were included in this study. Gastric cancer and paired normal tissues were collected. The expression of MEG3 was tested through real-time quantitative poly-merase chain reaction (qRT-PCR). Western blot analysis was used to detect the expression of P53 and MDM2 in gastric cancer and eval-uate their correlations with MEG3. Results:The expression of MEG3 decreased in cancer tissues (7.98±0.19) relative to the correspond-ing normal tissues (9.47±0.18) (P<0.05). P53 and MDM2 showed negative relationships in the gastric cancer and normal tissues. A posi-tive relationship was found between P53 and MEG3 (r=0.591, P<0.05), whereas a negative relationship was found between MDM2 and MEG3 (r=?0.346, P<0.05). The median survival time was significantly prolonged in patients with high MEG3 expression compared with patients with low MEG3 expression. Conclusion:MEG3 exerts an inhibiting effect on the development of gastric cancer. MEG3, P53, and MDM2 may have important relationships in the biological mechanisms of gastric cancer development. Detecting the expression level of MEG3 may be useful for the prognosis of gastric cancer.
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OBJECTIVE: Long noncoding ribonucleic acids (RNAs) nowadays emerge as important biomarkers or potential therapeutic targets discussed in human cancers. Among them, maternally expressed gene 3 (MEG3) is known to be decreased in a variety of malignancies. MATERIALS AND METHODS: Quantitative reverse transcription‑polymerase chain reaction (qRT‑PCR) was performed to detect the expression of MEG3 in forty pairs of lung cancer (LC) tissues. Overexpression of MEG3 was carried out, and we determined its effect on cell proliferation, apoptosis, and migration evaluated by cell counting kit‑8, flow cytometric, and transwell analysis. Messenger RNA and protein expression of MYC were determined by qRT‑PCR and western blot, respectively. RESULTS: The expression of MEG3 was downregulated in LC tissues. Forced expression of MEG3 led to reduced abilities of cell proliferation and elevated apoptosis rate. It also slightly inhibited cell migration capacity in vitro. In addition, MYC was inhibited by MEG3 overexpression at both transcriptional and translational levels. CONCLUSION: Our findings revealed MEG3 could regulate LC progression and serve as an important target for LC treatment.
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AIM:To investigate the expression of long non-coding RNA maternally expressed gene 3 (MEG3) in colorectal cancer ( CRC) cells, and to observe the effect of MEG 3 on the invasion and migration of CRC cells .METH-ODS:The levels of MEG3 in human normal colon cell NCM 460 and CRC cells SW48 and LoVo were detected by real-time PCR.MEG3 was over-expressed by plasmid transfection , and the effects of MEG 3 on the invasion and migration of SW 48 and LoVo cells were analyzed by Transwell assay and wound healing assay .The expression of matrix metalloproteinase ( MMP) family proteins was determined by Western blotting .RESULTS:The level of MEG3 was down-regulated in CRC cells compared with normal colon cell NCM 460.The invasion and migration of CRC cells were reduced after MEG 3 over-ex-pression.Transwell invasion and migration assays showed that the numbers of transmembrane SW 48 and LoVo cells were smaller in MEG3 over-expression group than control group (P<0.05).The cell spaces were broader after MEG3 over-ex-pression in the wound healing assay , indicating that MEG3 over-expression inhibited the mobility of CRC cells .Meanwhile, over-expression of MEG3 reduced the expression of MMP-2 and MMP-9, and elevated the expression of tissue inhibitor of metalloproteinase-2 (TIMP-2).CONCLUSION:The expression of MEG3 is down-regulated in CRC cells.Over-expres-sion of MEG3 inhibits the invasion and migration of CRC cells .TIMP-2, MMP-2 and MMP-9 might play an important role in this regulation .
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Objective To construct a maternally expressed gene 3(MEG3)expression plasmid vec-tor,and to obtain MEG3 over-expressed human pancreatic carcinoma SW1990 cells by transfection,and to ana-lyze the effect of MEG3 overexpression on the proliferation of human pancreatic carcinoma SW1990 cells. Methods A complete gene sequence based on the sequence of MEG3 in the GenBank was designed and inser-ted into the eukaryotic expression vector pcDNA3. 0 to construct recombinant plasmid pcDNA3. 0-MEG3. It was identified by sequencing and transfected into human pancreatic carcinoma SW1990 cells. The expression of MEG3 in SW1990 cells was confirmed by RT-PCR. The effect of MEG3 on proliferation was evaluated by MTT assay. In this study,the SW1990 cells transfected by plasmid pcDNA3. 0 were named negative control group, and the usual SW1990 cells were named blank control group. Results A MEG3 expression plasmid vector-pcDNA3. 0-MEG3 was constructed successfully. And pcDNA3. 0-MEG3 vector was transfected into SW1990 cells successfully. The expression of MEG3 at mRNA in MEG3-SW1990 cells increased significantly,about 895 times(F = 73. 592,P ﹤ 0. 01). The results of MTT assay indicated that over-expressed MEG3 could obviously inhibit SW1990 cells proliferation in vitro. After SW1990 cells transfected with pcDNA3. 0-MEG3 for 72 hours, the absorbance value was 0. 81 ± 0. 06,with a statistically significance(F = 33. 489,P ﹤ 0. 01)compared with negative control group(1. 17 ± 0. 07)and blank control group(1. 08 ± 0. 03). Conclusion A MEG3 expre-ssion plasmid vector-pcDNA3. 0-MEG3 is constructed successfully. It is confirmed that MEG3 and its product have obvious inhibitory effects for the proliferation of human pancreatic carcinoma SW1990 cells.
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Maternally expressed gene 3 (MEG3) is a tumor-suppressing gene,and MEG3 RNAs,its products,are a series of long noncoding RNAs.The MEG3 gene is lost in kinds of human tumors,further more,the methylation of related DNA region is directly associated with the deficiency of MEG3 expression.Studies show that MEG3 gene and MEG3 RNAs can inhibit cell proliferation and induce apoptosis,which is associated with the fuction of tumor suppressor gene p53.