Journal Article

miRNAs: possible regulators of toll like receptors and inflammatory tumor microenvironment in colorectal cancer

Shehata, Hanan, Hossam, Nourhan, Aboelhussein, Marwa, Eissa, Sanaa, Matboli, Marwa, Ismail, Nahed, Farag, Doaa, Hassan, Mohamed

2024

Overview

Background Colorectal cancer (CRC) is ranked as the third most commonly diagnosed cancer and the third cause of cancer related deaths. CRC is greatly attributed to genetic and epigenetic mutations and immune dysregulation. Tumor aberrant expression of Toll-like Receptors (TLRs) can contribute to tumorigenesis. Recent studies suggested that microRNAs act as direct ligands of TLRs altering their expression and signaling pathways. Aim To prove our concept that specific miRNA mimics may act as antagonists of their specific toll like receptors inhibiting their expression that could limit the release of pro-inflammatory and pro-tumorigenic cytokines leading to apoptosis of tumor cells. Methods From public microarray databases, we retrieved TLRs and miRNAs related to CRC followed by in silico docking of the selected miRNA ligands into the TLRs. Clinical validation after co-immunoprecipitation of TLRs and their interacting miRNA ligands was done. Expression of TLRs 1, 7,8 was determined by ELISA while miRNAs was measured by RT-qPCR. In addition, microRNA mimics of the down regulated miRNAs were transfected into human CRC cell lines. Results Our data demonstrate that TLRs 1, 7, 8 are up regulated in CRC compared to controls. Further, three miRNAs (-122, -29b and -15b) are relatively downregulated, while 4 miRNAs (-202, miRNA-98, -21 and -let7i) are upregulated in CRC patients compared to those with benign tumor and healthy controls. Transfection of down regulated miRNA mimics into CRC cell lines resulted in a significant reduction of the number and viability of cells as well as down regulating the expression of TLRs 1, 7 and 8 with ultimate reduction of downstream effector IL6 protein, suggesting that these miRNAs are negative regulators of carcinogenesis. Conclusion MicroRNAs could act as antagonistic ligands of TLRs limiting the inflammatory tumor microenvironment. Key points • Specific miRNAs were identified by in silico docking as signaling antagonists of 3 TLRs and were validated in clinical samples. • TLRs 1, 7, 8 were upregulated while their miRNAs (-122, -29b and -15b)were down regulated in CRC. • Transfection of downregulated miRNA mimics into CRC cell lines resulted in downregulation of TLRs that was associated with reduction in IL6 protein and tumor growth. • The present study proposed a novel approach that enables a reliable integration of Toll like receptors and miRNAs in CRC pathogenesis.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Analysis / Antigens / Apoptosis / Bioinformatics / Biomedical and Life Sciences / Biomedicine / Cancer / Cancer Research / Cancer therapies / Carcinogenesis / Care and treatment / Cell Line, Tumor / Colonoscopy / Colorectal cancer / Colorectal carcinoma / Colorectal Neoplasms - genetics / Colorectal Neoplasms - metabolism / Colorectal Neoplasms - pathology / Cytokines / Development and progression / Diagnosis / Docking / Down-regulation / Effector cells / Enzyme-linked immunosorbent assay / Epigenetic inheritance / Epigenetics / Female / Gene expression / Gene Expression Regulation, Neoplastic / Genetic aspects / Health aspects / Health Promotion and Disease Prevention / Humans / Immune system / Immunoprecipitation / Inflammation / Inflammation - genetics / Inflammation - metabolism / Ligand / Ligands / Male / Medicine/Public Health / Metastasis / MicroRNA / MicroRNAs / MicroRNAs - genetics / MicroRNAs - metabolism / Mimic / miRNA / Mutation / Oncology / Ontology / Pathogenesis / Patients / Rankings / Scientific equipment and supplies industry / Signal Transduction / Surgical Oncology / Toll-like receptor / Toll-Like Receptor 1 - genetics / Toll-Like Receptor 1 - metabolism / Toll-Like Receptor 7 - genetics / Toll-Like Receptor 7 - metabolism / Toll-Like Receptor 8 - genetics / Toll-Like Receptor 8 - metabolism / Toll-like receptors / Toll-Like Receptors - genetics / Toll-Like Receptors - metabolism / Transfection / Tumor cell lines / Tumor cells / Tumor microenvironment / Tumor Microenvironment - genetics / Tumorigenesis / Tumors