Background: Omega 3 polyunsaturated fatty acid (Omega-3PUFA) is one of the essential nutrients for human body involved in intracellular metabolic regulation and cell signaling. Previous studies have shown that Omega-3PUFA is involved in the pathogenesis of digestive system tumors, including colorectal cancer (CRC), however, the effects of Omega-3PUFA on CRC has not been fully elucidated. In the current study, we evaluated whether Omega-3PUFA can alleviate N-methyl-N-nitrosourea(MNU) induced CRC in a rat model and illustrated the potential mechanism. Methods: The effects of Omga-3PUFA on MNU-induced colorectal cancer in rats were analyzed by in vivo experiments. The viability, apoptosis, colony formation and invasion of CRC cells treated with Omga-3PUFA were detected by CCK8, flow cytometry, clone formation assay and transwell invasion assay. The expression of apoptosis-related proteins in CRC cells treated with Omga-3PUFA was detected by Western blotting. Finally, after adding PI3K activator, the viability, apoptosis and protein expression of CRC cells treated with Omga-3PUFA were detected by CCK8, flow cytometry and Western blotting. Results: Our results showed that Omega-3PUFA attenuated MNU-induced CRC in rats and inhibited AKT/Bcl-2 signaling in rats. In addition, Omega-3PUFA inhibited CRC cell proliferation and induces CRC cell apoptosis. Moreover, Omega-3PUFA inhibited CRC cell colony formation and invasion, and inhibited PI3K/AKT/Bcl-2 signaling in CRC cells. Furthermore, The effects of Omega-3PUFA on cell proliferation and apoptosis were inhibited by blocking PI3K/AKT signaling. Conclusion: Omega-3PUFA can attenuate MNU-induced colorectal cancer in rats by blocking PI3K/AKT/Bcl-2 signaling, which suggests that Omega-3PUFA may be a potent agent for CRC treatment.

Background: Increasing attention has been drawn the prognostic value of inflammatory indices for colorectal cancer (CRC). However, the prognostic value of the preoperative C-reactive protein to prealbumin ratio (CPAR) in CRC remains unclear. Methods: A retrospective study was conducted with 794 patients who had CRC and underwent radical surgical resection. The predictive performance of the inflammatory indices was analyzed and compared using the area under the timedependent receiver operating characteristic curve. A competing risk regression model and Cox proportional hazard model were used to analyze the effects of CPAR on disease-free survival (DFS) and overall survival (OS), respectively. Results: Patients with high CPAR (>7.25) had poor survival outcome. The CPAR had the best predictive performance among all inflammatory indices, and was significantly associated with several characteristics of tumor invasion, including histological grade, tumor stage, and tumor size. Multivariate analysis showed that high CPAR was independently associated with poor DFS (subdistribution hazard ratio = 2.28, 95% confidence interval [CI]: 1.74-2.82) and OS (hazard ratio = 1.78, 95% CI: 1.60-1.96). Conclusion:Preoperative CPAR assessment could serve as an effective and reliable tool for prognostic prediction in patients with resectable CRC.colorectal cancer, C-reactive protein to prealbumin ratio, disease-free survival, inflammatory index, overall survival | INTRODUCTIONGlobally, colorectal cancer (CRC) is the third most common malignancy and the second leading cause of cancer death. 1 There have been great improvements in our understanding of its etiology, risk factor, molecular biology, and clinical aspects over the past decades, but it still accounts for nearly 10% of the global cancer burden, with over 1.9 million new diagnoses and 0.9 million deaths in 2020. 2 Radical surgery is the preferred treatment for patients with resectable CRC, but for patients who undergo radical resection, the prognosis is still poor, with 60% of patients surviving for 5 years. 3 Tumor progression, including recurrence and distant metastasis, remains a major concern for patients after surgery.