| Objective: To study the relationship between expressions of miR-217 and mitogen-activated protein kinase 1(MAPK1)in gastric carcinoma, analyze whether MAPK1 is the target gene of miR-217 by bioinformatics analysis and explain the molecular mechanism by which miR-217 regulate MAPK1.Methods: Firstly, 20 miRNAs were found to be able to bind with MAPK1 by bioinformatics software, and among these miRNAs, miR-217 was the most possible one to bind with MAPK1. Immunohistochemistry was used to test the relationship between expression of MAPK1 and the clinicopathologic feature of gastric carcinoma in 58 gastric carcinoma tissues and 22 adjacent gastric mucosa tissues. qRT-PCR and Western blot were used to detect the expression of miR-217 and that of MAPK1,respectively, and the relationship between their expressions were analyzed; in gastric carcinoma cell lines with different differentiated degrees, expressions of miR-217 and MAPK1 were respectively detected by qRT-PCR and Western blot, and relationship between expressions of miR-217 and MAPK1 and that between their expressions and the occurrence of gastric carcinoma were analyzed; in recombinant cell lines SGC-7901-miR-217 mimics, SGC-7901-miR-Scramble, SGC-7901-miR-217-PM and SGC-7901, qRT-PCR and Western blot were used to detect the expression of miR-217 and that of MAPK1, respectively; whether miR-217 could regulate expression of MAPK1 was analyzed, so as to prove that miR-217 was the target gene of MAPK1.Results:(1) As detected by bioinformatics methods, there were 20 target miRNAs that could bind with MAPK1; miR-217 was the most possible one to bind with MAPK1,and MAPK1 might be the target gene of miR-217.(2) Positive expression rates of MAPK1 in gastric carcinoma tissues and adjacentnormal gastric mucosa tissues were respectively 74.1%(43/58)and 13.6%(3/22), with significant statistical difference in positive expression rate between them(P<0.05).(3) Expression of MAPK1 in gastric carcinoma tissues was not correlated with age and gender(P>0.05); positive expression rate of MAPK1 in moderately and highly differentiated gastric carcinoma was 48.0%, which was lower than the rate of93.9% in poorly differentiated gastric carcinoma; positive expression rate of MAPK1 in clinical stage I + II was 57.7%, which was lower than the rate of 87.5% in clinical stage III + IV; positive expression rate of MAPK1 in carcinoma with lymphatic metastasis was 90.6%, which was higher than the rate of 53.8% in carcinoma without lymphatic metastasis; positive expression rate of MAPK1 in patients with distant metastasis was 87.1%, which was higher than the rate of 39.3% in patients without distant metastasis, with statistical significance regarding all the above-mentioned differences(P<0.05).(4) Expression level of miR-217 was not correlated with age and gender(P>0.05); miR-217 had lower expression level in poorly differentiated gastric carcinoma than in moderately and highly differentiated gastric carcinoma; miR-217 had lower expression in gastric carcinoma patients with lymphatic and distant metastasis than in gastric carcinoma patients without metastasis(P < 0.05).(5) miR-217 had significant lower expression in gastric carcinoma than in adjacent tissues(P < 0.05); MAPK1 had significant higher expression in gastric carcinoma than in adjacent tissues(P < 0.05).(6) MAPK1 had higher expression in poorly differentiated gastric carcinoma cell line BGC-823, while miR-217 had lower expression level; MAPK1 had lower expression in moderately and highly differentiated human gastric carcinoma cell line SGC-7901、 MKN-28, while miR-217 had higher expression level(P<0.05).Among gastric carcinoma cell lines with different differentiated degrees, there was significant difference in expression of MAPK1 and there was also significant difference in expression of miR-217(P<0.05).(7) In recombinant cell line SGC-7901-miR-217 mimics, miR-217 had increased expression, while MAPK1 showed low expression; however, when in the three celllines―SGC-7901, SGC-7901-miR-Scramble and SGC-7901-miR-217-PM, there was down-regulated expression of miR-217, without significant difference in expression of miR-217 among them, while there was high expression of MAPK1, without difference in expression of MAPK1 among them.Conclusions:(1) MAPK1 had high expression in gastric carcinoma than normal gastric mucosa tissue, miR-217 had low expression in gastric carcinoma than normal gastric mucosa tissue. MAPK1 high expression and miR-217 low expression am may correlate with progress and development of gastric carcinoma.(2) Expressions of miRNA-217 and MAPK1 were negatively correlated in gastric carcinoma; expression of MAPK1 could be down-regulated by miRNA-217. |
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