Gene Expression and Signifi cance of JAK-STAT and ras-MAPK Signaling Pathways in Gastric Cancer Cells

Objective To investigate the expression and correlation of ras, signal transducers and activators of transcription 3 (STAT3) and p38MAPK in gastric cancer cells. Methods RT-PCR and Western blot methods were used to detect the expression of ras, STAT3 and p38MAPK of gastric cancer cell lines MKN45,SGC7901and MKN28. Results The mRNA expression levels of ras, STAT3, p38MAPK in human poorly differentiated gastric cancer cell line MKN45 were signifi cantly higher than those in both human moderately differentiated gastric cancer cell line SGC7901 (P ＜0.05) and human well-differentiated gastric cancer cell line MKN28 (P＜0.01). The protein levels of ras, STAT3, p38MAPK in human poorly differentiated gastric cancer cell line MKN45 were significantly higher than those in human moderately differentiated gastric cancer cell line SGC7901 (P ＜0.05) and human well-differentiated gastric cancer cell line MKN28 (P＜0.01). There was a signifi cant positive correlation between mRNA expression of ras, STAT3（r=0.94,P＜0.01）and p38MAPK（r=0.89,P＜0.01）. The mRNA expression of STAT3 and p38MAPK was positively correlated with each other (r=0.76,P＜0.05). There was a significant positive correlation between protein expression of ras and STAT3（r=0.97,P＜0.01）. The protein levels of ras and p38MAPK was positively correlated（r=0.72，P＜0.05）.The protein levels of STAT3 and p38MAPK was positively correlated(r=0.69，P＜0.05). Conclusion The overexpressions of ras, STAT3 and p38MAPK play an important role in carcinogenesis, development and differentiation of gastric cancer. ras-MAPK and JAK-STAT pathway imbalance may be an important cause of gastric cancer.