| Objective: Colorectal cancer is one of the most common malignant tumors in the world which is seriously harmful to human health and its development and other biological behaviors are influenced by environment and gene regulation.In the clinical treatment of colorectal cancer,besides surgical operation as the core,postoperative adjuvant chemotherapy,neoadjuvant chemoradiotherapy,targeted therapy and other kinds of treatments are developing rapidly.As one of the most common first-line chemotherapeutic drugs,oxaliplatin and its curative effect and prognosis have been closely watched by medical scientists.In recent years,with the deepening of the research on non-coding RNA,Lnc RNA has become a new hot topic in genetic science,and related studies have confirmed that the abnormal expression of Lnc RNA can definitely take part in invasion,metastasis,development of a wide variety of tumor and even the drug resistance.So in the existing based on the study of the colorectal cancer chemotherapy drugs,it has greater significance to conduct more precise researches that combine with the regulation mechanism of Lnc RNA.It can not only clear the molecular mechanism but also can provide help to clinical individualized treatment and prognosis evaluation.Methods: This study selected 157 cases colorectal cancer patients who accepted surgery and adjuvant chemotherapy of oxaliplatin in colorectal department of the first hospital of China medical university.After in situ hybridization experiment,evaluate the expression level of tumor and adjacent tissue,we analysis the Loc554202 expression level with clinical pathological parameters and follow-up prognosis,and excavation the relevance between the expression level and survival situation.The differences of expression level were found between oxaliplatin sensitive cell lines HCT116,SW480 and drug-resistant cell lines HCT116/l and SW480/L and then the Loc554202 high expression in HCT116 and SW480 and low expression in HCT116/L and SW480/L cell model were constructed by transfection by c DNA-Loc554202 and sh RNA-Loc554202.After transfection efficiency test by q RT-PCR,the effects of interference Loc554202 expression on the drug resistance about cell oxaliplatin were investigated by CCK-8.To explore the mechanism of Loc554202 affecting drug resistance in tumor cells,the different expression level of classical intron RNA mi R-31 were found in the cell models that interfered with Loc554202 expression level by q RT-PCR and Western Blot,and so was the m RNA that was changed.Thus,the regulation of the host gene Loc554202 on mi R-31 was determined and ABCB9 was found that could be the key factor to explain the regulatory mechanism of Loc554202.In the end,the mi R-31 high and low expression cell model were constructed by transfection with mimic-mi R-31 and inhinitor-mi R-31 in HCT116,SW480 and HCT116/L and SW480/L.Verify the difference expression of ABCB9 in tumor cells after interfering with mi R-31 expression level by q RT-PCR and Western Blot.Though the recovery experiment and luciferase report,it was explained that Loc554202 could regulate the expression of ABCB9 to adjust the durg resistance of oxaliplatin on colorectal cells through mi R-31.Results: 1.By in situ hybridization experiment,it was found that the orange-brown staining of Loc554202 was darker 155.24±59.94(7-256),compared with the expression in normal intestinal mucosa tissue64.16±28.95(0-117).2.The expression level of Loc554202 in colorectal cancer was negatively correlated with the prognosis DFS and OS of the colorectal cancer patients who accepted oxaliplatin chemotherapy.The survival period of the patients with high expression of Loc554202 was 40.63±4.52 months,and the survival time of OS was 56.19±3.99 months.In patients with low expression,the survival time of DFS was 56.25±4.85 months,and the survival time of OS was 67.12±4.29 months.The prognostic association is also present in DFS of adenocarcinoma and colon cancer patients.COX multivariate analysis suggested that the expression level of Loc554202 was an independent factor affecting the survival of patients with oxaliplatin chemotherapy,especially in colon cancer patients.3.At the cellular level,Loc554202 and mir-31 were found to be highly expressed in HCT116/L and SW480/L drug-resistant tumor cells(P < 0.01).The expression level of mir-31 was positively regulated by Loc554202 expression change after constructed the cell models by interfering the expression level of Loc554202,meanwhile,the expression of ABCB9 was negatively regulated by the expression of Loc554202.4.Loc554202 can enhance the resistance of tumor cells to oxaliplatin and reduce the effect of drugs on tumors by interfering the expression level in cell models.5.ABCB9 was both subjected to negative regulation in the cellular level and the protein level after constructed the cell models of mi R-31 abnormal expression.It was verified that the m RNA of mir-31 and ABCB9 combined in the 3 ’-utr region by Luciferase experiment.6.The expression level of ABCB9 was inhibited after improving expression of Loc554202 in HCT116 and SW480,and was increased after cutting down the expression of mir-31 by inhibitor-mi R-31.It was confirmed that Loc554202 could affect the drug resistance of colorectal cancer to oxaliplatin by changing the expression level of ABCB9 through mi R-31.Conclusion: 1.Loc554202 is highly expressed in colorectal tumor tissues,especially in adenocarcinoma and colon cancer,and is associated with the survival of patients with oxaliplatin chemotherapy.with Loc554202 can alter the expression level of mir-31 and the efficacy of oxaliplatin in the treatment of tumors.3.Loc554202 could affect the drug resistance of colorectal cancer to oxaliplatin by altering the combination between ABCB9 and mi R-31 through changing the expression level of mi R-31. |
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