The Role Of MiR-339 In The Development Of Gastric Cancer

Part 1:Detection miR-339 level in serum and gastric cancer tissues of patients with gastric cancer and its correlation with clinical dataObjective:To investigate miR-339 level in serum and gastric cancer tissues of patients with gastric cancer and its correlation with clinical data.Methods:Serum samples,cancer tissues,paracancerous tissues of 115 gastric cancer patients and serum samples of 115 healthy people from January 2012 to August 2016 were collected;the sex,age and other related clinical data of 115 patients with gastric cancer and 115 healthy people were collected.Comparison serum miR-339 levels in gastric cancer patients with healthy people,comparison the cancer tissues miR-339 levels with paracancerous tissues miR-339 levels in gastric cancer patients;the correlation of serum miR-339 levels in gastric cancer patients with gender,age,tumor size,lymph node metastasis,distant metastasis,tumor differentiation and tumor staging was analyzed.Results:The level of serum miR-339 in gastric cancer patients was significantly lower than that in healthy people;the level of miR-339 in gastric cancer tissues was significantly lower than that in adjacent tissues in gastric cancer patients;there was no significant difference in serum miR-339 levels among patients with different gender,age,tumor size and distant metastasis and there were significant differences in serum miR-339 levels among patients with different degrees of tumor differentiation,tumor stage and lymph node metastasis.Conclusion:The level of serum miR-339 in patients with gastric cancer was significantly lower than that in healthy people and the level of miR-339 in gastric cancer tissues was significantly lower than that in adjacent tissues;the serum levels of miR-339 in gastric cancer patients were not significantly correlated with sex,age,tumor size,and negatively correlated with lymph node metastasis,tumor differentiation and tumor staging.Part 2:To investigate the role of miR-339 in proliferation and apoptosis of gastric cancer cell line SGC7901 and its mechanismObjective:To investigate the role of miR-339 in proliferation and apoptosis of gastric cancer cell line SGC7901 and its mechanism.Methods:Overexpression or silencing of miR-339 in gastric cancer cell line SGC7901,the genes level of BCL-2,BCL-XL,C-MYC,IL-6,TNF-alpha and KC in SGC7901 cells was detected by PCR;the expression of BCL-2,BCL-XL,p-JNK and p-Akt protein in SGC7901 cells was detected by Western blot;the cell clone formation ability in SGC7901 cells was observed under light microscope;the proliferation of SGC7901 cells were detect by MTT assay and Brdu assay;the apoptosis of SGC7901 cells was detected by flow cytometry.Results:After silencing miR-339,the genes level of BCL-2,BCL-XL,C-MYC,IL-6,TNF-alpha and KC and the proteins level of BCL-2,BCL-XL,p-JNK and p-Akt in SGC7901 cells were significantly increased;after overexpression of miR-339,the genes level of BCL-2,BCL-XL,C-MYC,IL-6,TNF-alpha and KC and the proteins level of BCL-2,BCL-XL,p-JNK and p-Akt were significantly decreased;after silencing miR-339,the ability of clone formation and proliferation of SGC7901 cells was significantly increased,and the apoptotic cells were significantly reduced;after overexpression of miR-339,the clone and proliferation ability of SGC7901 cells were significantly reduced and the apoptotic cells significantly increased.Conclusion:miR-339 may inhibit the activation of p-JNK and p-Akt signaling pathways and regulate the genes function of Bcl-2,BCL-xl,c-myc,IL-6,TNF-a and KC,affecting the proliferation and apoptosis of SGC7901 cells.Part 3:To investigate the role of miR-339 in proliferation and apoptosis of gastric cancer cell line SGC7901 and its mechanismObjective:To investigate the role of miR-339 to gastric cancer cell line SGC7901 in nude mice subcutaneous tumorigenesis.Methods:The 24 nude mice were randomly divided into 4 groups:silent miR-339 group(shmiR-339 group),silent miR-339 solvent control group(shmiR-339 group),over expression miR-339 group(miR-339 group),overexpression of miR-339 solvent control group(NC group).The overexpressing or silenced gastric cancer cell line SGC7901 was injected subcutaneously into nude mice,and the size of subcutaneous tumor in nude mice were observed after 4 weeks.Results:After the silence of miR-339,the size of subcutaneous tumor in nude mice increased significantly.After overexpression of miR-339,the size of subcutaneous tumor in nude mice decreased significantly.Conclusion:After the silence of miR-339,the subcutaneously tumorigenicity of gastric cancer cell line SGC7901 in nude mice increased,and overexpression of miR-339 could significantly inhibit the subcutaneously tumorigenicity of gastric cancer cell line SGC7901 in nude mice.