Abstract: Objective To investigate the effect and potential molecular mechanism of PTGS2 on the prognosis of colon cancer patients. Methods The transcriptomic and proteomic data of pan-cancer were collected from TCGA, HPA, UALCAN and other databases, and the expression pattern and prognostic value of PTGS2 were analyzed by combining the clinical data such as staging, histology, survival time and so on. Based on GSEA, the biological functions which were significantly activated in patients with high expression of PTGS2 were identified and the colon cancer cell line SW480 was used as an example for in vitro validation. PTGS2 over-expressing cell strains were constructed, and the effect on cell proliferation was determined by CCK8 method. Different concen- trations of H₂O₂ were used to form gradient oxidative stress, and the changes in cell antioxidant capacity were detected. The regulatory mechanism was preliminarily verified by Western blot. Results The transcription and expression of PTGS2 were found to be significantly up-regulated in colon cancer patients (P＜0.05), and the increased expression of PTGS2 was associated with an increased mortality risk (P＜0.05). Data analysis and in vitro experiments showed that over-expression of PTGS2 may promote the proliferation of colon cancer cells by activating the mTOR pathway. The antioxidant effect of cells was regulated by up-regulating oxidative stress regulatory proteins SOD2 and NRF2. Conclusions PTGS2 is a potential risk factor for colon cancer and its over-expression promotes cell proliferation, enhances cell antioxidant effect and is associated with poor prognosis of colon cancer patients.

Key words: colon cancer, prostaglandin-endoperoxide synthase 2(PTGS2), prognosis, proliferation, antioxidant capacity