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Purpose To investigate the effect of autophagy intervention on ferroptosis and drug resistance of colorectal canc-er cells and its molecular mechanism.Methods The human colorectal cancer cell lines HCT-8,COLO205,HCT-116,SW620,and SW480 were cultured.HCT-116 cells with moder-ate expression of LC3 were screened,and the expression differ-ences of LC3,p62,Keap1,Nrf2,GPX4 proteins,Fe2+,GSH,and MDA between them and OXA-resistant HCT-116/OXA cell lines were detected.The expression levels of LC3,p62,Keap1,Nrf2,GPX4,Fe2+,GSH and MDA were assessed in HCT-116/OXA cells through the intervention of autophagy and ferroptosis intervention agent combined with oxaliplatin.The proliferative activity and sensitivity to oxaliplatin in each group were detected by CCK-8 assay.Cell growth and invasion ability of each group were detected by plate cloning and Trans well assay.Results LC3,p62 and GPX4 expression levels of HCT-116 cells in the 5 groups were moderate.Compared with HCT-116 cells,HCT-116/OXA was less sensitive to oxaliplatin,and the proteins of p62,Nrf2 and GPX4 were highly expressed,LC3 and Keap1 were lowly expressed,and the expression of Fe2+,GSH and MDA were increased(P＜0.05).The levels of LC3,Keap1 protein,Fe2+and MDA in Rapa and Rapa+Fer-1 groups were higher than those in Fer-1 and control groups,while p62,Nrf2,GPX4 and GSH levels were lower.The expressions of GPX4 pro-tein and GSH in Rapa+Fer-1 group were lower than those in Rapa group(P＜0.05).In the autophagy inhibitor group,LC3,p62,Nrf2,GPX4 and GSH were highly expressed in the CQ and CQ+Erastin groups compared with the control and Eras-tin groups,while Keap1 protein,Fe2+and MDA were low.The levels of GPX4 protein and GSH in Erastin group were lower than those in the other three groups,and the levels of Fe2+and MDA were higher than those in the other three groups(P＜0.05).The combination of autophagy activator OXA showed that Rapa intervention group had higher chemical sensitivity to OXA,less number of migrating cells and lower cell proliferation activity than the other three groups.The sensitivity of Rapa+Fer-1 group to oxaliplatin was lower than that of Rapa group,but higher than that of Fer-1 group and control group(P＜0.05).There was no significant difference between Fer-1 group and con-trol group(P＜0.05).Compared with the control group,the cell activity,migration capacity and clonogenesis capacity of Erastin,CQ+Erastin and CQ groups were decreased when auto-phagy inhibitor was combined with OXA,and the Erastin group was the lowest,while the CQ+Erastin group was higher than the Erastin group,and lower than the CQ group(P＜0.05).Con-clusion In colorectal cancer,autophagy is involved in the regu-lation of ferroptosis,and intervention in autophagy can regulate ferroptosis in colorectal cancer cells through the p62-Keap1/Nrf2-GPX4 pathway,thereby reversing oxaliplatin resistance.
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Background: Endoscopic submucosal dissection (ESD) has become the preferred treatment of early colorectal cancer. PDCD4 and autophagy have important clinical significance in the pathogenesis of colorectal cancer. Aims: To explore the expressions and significance of apoptosis factor PDCD4 and autophagy factors LC3Ⅱ and p62 in colorectal cancer. Methods: Fifty-four early colorectal adenocarcinoma patients treated by ESD from Jan. 2015 to Nov. 2020 at Binzhou Medical University Hospital were collected. The expressions of PDCD4, LC3Ⅱ and p62 were detected by immunohistochemistry, and the correlations with clinicopathological factors were analyzed. The differential expression of PDCD4 in pan-cancer was analyzed by bioinformatics analysis. Results: Expression of PDCD4 was associated with the long-diameter of paracancer adenoma (P<0.05), and expressions of LC3Ⅱ and p62 were associated with the long-diameters of adenocarcinoma and paracancer adenoma (P<0.05). The positive expression of PDCD4 in P-NIMM was located in the nucleus, while the positive expression in adenocarcinoma was located in cytoplasm. The nucleus/cytoplasm ratio of PDCD4 was significantly higher in P-NIMM than in P-LGIN, P-HGIN and adenocarcinoma (P<0.05), and the nucleus/cytoplasm ratio of PDCD4 was significantly higher in P-LGIN, P-HGIN than in adenocarcinoma (P<0.05). The positive expression rates of LC3Ⅱ and p62 were significantly higher in adenocarcinoma than in P-NIMM and P-LGIN (P<0.05). In P-LGIN, P-HGIN and adenocarcinoma, the expression of PDCD4 was negatively correlated with the expressions of LC3Ⅱ and p62 (P<0.05). The bioinformatics analysis showed that expression of PDCD4 was significantly reduced in a variety of malignant tumors including colorectal cancer (P<0.05). Conclusions: The inhibition of apoptosis and activation of autophagy may promote the occurrence of colorectal cancer, and its mechanism may be related to the intracellular transposition of PDCD4 that inhibits cell apoptosis and enhances autophagy, and activating cellular autophagy may further accelerate the degradation of PDCD4 and thus reducing its cancer inhibiting effect.
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Purpose To investigate the expression of Beclin1, LC3 and mTOR in colorectal cancer ( CRC) and their significance. Methods Immunohistochemistry, Western blot and real-time PCR were employed to detect the expression of Beclin1, LC3 and mTOR in CRC. Results The positive expression rate of Beclin1, LC3 and mTOR in 242 cases of CRC was 90. 50%, 87. 19% and 46. 28%, respectively, which were higher than that in adjacent tissues ( P0. 05). The expres-sion of LC3 was positively correlated with Beclin1 and negatively correlated with mTOR in colorectal cancer (rs =0. 593, P0. 05). Kaplan-Meier survival analysis re-vealed that the five-year survival rate of patients without nodal metastasis, positive expression of Beclin1, LC3 and negative expression of mTOR was higher than those with nodal metastasis, negative expression of Beclin1 and LC3, and positive expression of mTOR. Cox survival analysis results revealed that LC3, mTOR and lymphnode metastasis were independent prognostic factors. The results of IHC, real-time PCR and Western blot in fresh CRC tissues indicated that the expression of Beclin1, LC3 and mTOR in colorectal cancer was significantly higher than that in adjacent tissues (P<0. 05). Conclusions The aberrant expression of Beclin1, LC3 and mTOR may be associated with the development and progression of colorectal cancer. The simultaneous detection of Beclin1, LC3 and mTOR genes in colorectal cancer may be helpful for the evaluation of the progressive degree and the judgment of prognosis.