The Expression Of CircRNA In Colorectal Cancer And Its Mechanism

Objective Colorectal cancer（CRC）is one of the top three malignancies in human incidence.Despite significant progress in modern treatment technology,its fatality rate is still high.In recent decades,there is no more suitable diagnostic and screening indicator than carbohydrate antigen.Circular RNA（circRNA）is an endogenous non-coding RNA（ncRNA）that regulates gene expression^[1].It was first discovered in the 1970s as the genome of some RNA viruses.Studies have found that circRNA has a large number,rich mechanisms and a wide range of influence,and plays an important role in the occurrence and development of colorectal cancer,lung cancer,gastric cancer,liver cancer and other malignant tumors^[2][3],so it may become a new biomarker or stage-specific RNA for the progression of colorectal cancer.In this study,the role of circRNA in the progression of colorectal cancer and the related mechanisms were investigated by analyzing the gene expression of different stages of colorectal cancer and the corresponding paracancer tissues.Methods From 2016 to 2018,9 patients with primary colorectal cancer with different pathological stages who underwent radical resection of colorectal cancer in the affiliated hospital of shandong academy of medical sciences and were pathologically confirmed were selected.There were 5 males and 4 females.Age:54-64years old,average:59.6 years old.According to the criteria of 2018.v2 NCCN guidelines,the following groups were divided according to postoperative pathological tumor invasion depth（T）and lymph node metastasis（N）,and the presence of distant metastasis（M）:group A:t1-3n0m0;Group B:t4a-bn0m0;Group C:t4a-bn1-2m0.The progression from A to B to C largely reflects the progression of colorectal cancer.Inclusion criteria:pathological diagnosis of primary colorectal cancer;No distant metastasis.Exclusion criteria:preoperative chemotherapy,radiotherapy,immunotherapy;Concomitant with other types of malignant tumors;The clinical data were incomplete.All enrolled patients signed relevant informed documents,and this study has been approved by the ethics committee of the affiliated hospital of shandong academy of medical sciences.CircRNA was extracted and treated from the samples of each group,and different circRNA from each group was screened out.Differential circRNA screening was performed for cancer and adjacent tissues of each group,with adjusted P<0.05and|log2FC|>2 as screening conditions.Cluster analysis was performed according to their expression values in each sample,and cluster diagram was made by cluster3.0.Sequence experiments were designed according to the progression sequence of colorectal cancer,and the most significant and mainstream gene groups were screened out to analyze the expression trend of different circrnas.The circRNA to which the mainstream expression trend belongs will be the target gene for further study.According to the measured values of circRNA and mRNA,the network was constructed by co-expression calculation.CircRNA at the center of the regulatory network was obtained according to the score of genetic properties.The function of unknown mRNA was predicted by the mRNA co-expressed around circRNA.Gene ontologies（GO）and Kyoto Encyclopedia of Genes and Genomes（KEGG）signaling pathways were analyzed using the database integrated via DAVID 6.7 website to screen the Genes with the most significant functions.P<0.05 was considered statistically significant.Results The analysis showed that there were 424 circRNA differences between group A and para-cancer tissues,among which 165 circrnas were decreased and 239circrnas were increased.Group B had a total of 560,with a decrease of 284 and an increase of 276.There were a total of 409 in group C,which decreased by 190 and increased by 220（P<0.05,FC>1.5）.After that,the difference of circRNA in group A was verified in group B and C,and the expression trend was analyzed.The expression abundance of differentially expressed circrnas was verified for many times,and it was found that the main trend was that the expression level gradually decreased with the progression of colorectal cancer,and a total of 103 differentially expressed circrnas with statistical significance of copper were screened out.Combined with the circRNA with the first 10 circrnas of the co-expression regulation network gene attribute score,8 circrnas closely related to the progression of colorectal cancer were screened after the intersection of the two.They are:hsa_circ₀000007,hsa_circ₀001111,hsa_circ₀006977,hsa_circ₀079656,hsa_circ₀023608,hsa_circ₀024508,hsa_circ₀026694,hsa_circ₀029903.More than 500 related mrnas were screened through prediction,and further enrichment analysis of GO and KEGG was conducted.It was found that most of the genes and the hsa03010 pathway（P<0.05）were mainly involved in the processing and metabolism of ribosomal RNA,the splicing and processing of RNA and other cellular basic functional processes.The HINFP gene may be related to the transcription regulation of cell mitotic cycle G1/s.Hsa_circ₀079656 and HINFP gene in intersected circRNA have significant biological function relationship.Conclusion With the progression of colorectal cancer,the main trend of differential circRNA decreases.HINFP gene may be involved in transcriptional regulation of cell mitotic cycle G1/s.Hsa_circ₀079656 may affect the progression of colorectal cancer by affecting the HINFP gene.