Increased Expression of lncRNA LINC01139 as a Potential Biomarker of Colorectal Cancer

Colorectal cancer (CRC) ranks fourth and second among all types of cancer in terms of incidence and mortality rates, respectively. Although colorectal cancer screening has been effective in improving the prevention and treatment of this disease, many obstacles, including colorectal cancer metastasis, have severely hampered the prognosis of this disease. Long non-coding RNAs are a type of RNAi molecule that is classified into several functional groups and participates in some important cellular pathways. LncRNA-RNA interactions control mRNA translation and degradation or act as microRNA (miRNA) silencing sponges. LncRNA-protein interaction regulates protein activity in transcriptional activation and silencing. LncRNA guide, decoy, and scaffold transcriptional regulators regulate the enhancer or repressor region of coding genes to alter expression. Non-coding RNAs have attracted increasing attention from researchers due to their key role in regulating gene expression and potential effects on cell signaling pathways. These RNAs, as biomarkers, play an important role in the diagnosis, progression, and prognosis of colorectal cancer. This study investigated the change in the expression level of non-coding RNA LINC01139 in colorectal cancer compared to healthy tissue.

In this study, the expression change of the LncRNA LINC01139 gene from two databases, UALCAN and Gepia2, was investigated in colon adenocarcinoma tumor tissues compared to healthy tissue. Then, total RNA was extracted from 41 colorectal cancer tumor tissue samples and 41 healthy tissue samples adjacent to the tumor, and after qualitative and quantitative analysis of the extracted RNA, cDNA synthesis was performed using the kit. Then, by designing and synthesizing a specific primer, the expression level of LINC01139 non-coding RNA was measured in two tumor and healthy tissues using the Real-time RT-PCR technique. In the end, considering the Gapdh gene as a housekeeping gene, the resulting data were analyzed by Graph pad prism software.

Data analysis of this study based on bioinformatics analysis showed that the expression of non-coding RNA LINC01139 is decreased in colorectal tumors. This is even though the expression of this gene increases significantly in tumor tissues (both metastatic and non-metastatic) compared to the adjacent normal tissue, regardless of gender(P<0.0001). However, It was also shown that increased expression of LINC01139 non-coding RNA in tumor tissues can serve as a biomarker in identifying tumor tissues from healthy colorectal tissues(AUC=0.81, P<0.0001). as no significant expression difference between non-metastatic and metastatic samples (P>0.05).

Considering the known role of LINC01139 lncRNA in the HIF1α signaling pathway as a scaffold, the oncogenic function of LINC01139 lncRNA in liver cancer through the miR-30/MYBL2 axis and the strong Linc01139-PIP3 LncRNA interaction and the effect on the PIP3-AKT pathway. It seems that increased expression of cytoplasmic lncRNA LINC01139 and its function as an oncogene may be involved in colorectal carcinogenesis through signaling pathways.