ABSTRACT
Objective To investigate the effect of piR-9994 on the biological behavior of gastric cancer cells and its possible mechanism. Methods The expression of piR-9994 in gastric cancer cell lines (MGC803 and AGS) and normal gastric epithelial cells (GES-1) were detected by qRT-PCR. MGC803 cell line with piR-9994 overexpression and knockdown were constructed. The effects of piR-9994 expression changes on cell proliferation were detected by MTT and clone formation assay. The scratch wound healing assay and Transwell invasion assay were used to detect cell migration and invasion abilities. qRT-PCR and Western blot were used to detect cell proliferation and EMT-related genes expression. Results The expression level of piR-9994 in MGC803 cells was significantly higher than that in normal gastric epithelial cell line GES-1 (P < 0.05). The overexpression of piR-9994 promoted the proliferation, invasion and metastasis of gastric cancer cells, while piR-9994 knockdown had the opposite effect. piR-9994 expression was closely related to cell cycle, especially in S phase. The overexpression of piR-9994 promoted the expression of proliferation-related genes PCNA, CCND1 and Bcl-2, inhibited the expression of apoptosis gene C-PARP, and promoted the expression of EMT-related genes N-cadherin, MMP7, Twist and Vimentin; while piR-9994 knockdown had the opposite effect. Conclusion Abnormal expression of piR-9994 affects the proliferation, invasion, metastasis and EMT process of gastric cancer cells. piR-9994 may be a new biomarker and therapeutic target for gastric cancer.
ABSTRACT
Purpose To explore the relationship between the expression level of piR-9994 in gastric cancer and its clinical pathological features,and to analyze its correlation with PIWIL4 expression. Methods Express of piR-9994 and PIWIL4 in 76 cases of human gastric cancer tissue with different clinical stage and differentiated degree and matching adjacent tissue were detected by qRT-PCR and immunohistochemistry,respectively. Results The expression of piR-9994 in gastric cancer was 2. 3 times higher than that in paracancerous tissues (P = 0. 002 2) . The expression of piR-9994 in stage Ⅲ + Ⅳ gastric cancer was 3. 5 times higher than that in stage Ⅰ + Ⅱ (P = 0. 002) ,and the expression of piR-9994 in cancers with nerve invasion was 2. 5 times higher than that in cancers without invasion (P = 0. 036) . The positive expression of PIWIL4 in gastric cancer tissues was significantly higher than that in adjacent tissues (χ2 = 18. 346,P < 0. 001) ,and the expression of PIWIL 4 in stage Ⅲ +Ⅳ gastric cancer group was higher than that stage Ⅰ + Ⅱ gastric cancer group (χ2 = 8. 60,P = 0. 003) . There was a positive correlation between piR-9994 expression and PIWIL4 expression in gastric carcinoma (r = 0. 231,P < 0. 05) . Conclusion piR-9994 overexpression in gastric cancer tissues is closely related to tumor staging and nerve invasion,and piR-9994 may promote the occurrence and progression of gastric cancer by regulating PIWIL4 expression. piR-9994 may be a molecular markers for judging malignant degree and prognosis of gastric cancer.