Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Misr International University, Cairo, Egypt.
BMC Cancer. 2024 Jul 10;24(1):824. doi: 10.1186/s12885-024-12417-0.
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.
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.
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.
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.
MicroRNAs could act as antagonistic ligands of TLRs limiting the inflammatory tumor microenvironment.
结直肠癌（CRC）是第三大常见癌症，也是癌症相关死亡的第三大原因。CRC 主要归因于遗传和表观遗传突变以及免疫失调。肿瘤 Toll 样受体（TLR）的异常表达可能导致肿瘤发生。最近的研究表明，microRNAs 可以作为 TLRs 的直接配体，改变其表达和信号通路。
证明我们的概念，即特定的 miRNA 模拟物可以作为其特定的 toll 样受体的拮抗剂，抑制其表达，从而限制促炎和促肿瘤细胞因子的释放，导致肿瘤细胞凋亡。
从公共 microarray 数据库中，我们检索了与 CRC 相关的 TLRs 和 miRNAs，然后对选定的 miRNA 配体进行了 TLRs 的计算机对接。在共免疫沉淀 TLRs 及其相互作用的 miRNA 配体后进行了临床验证。通过 ELISA 测定 TLRs1、7、8 的表达，通过 RT-qPCR 测定 miRNAs 的表达。此外，将下调的 miRNAs 的 microRNA 模拟物转染入人 CRC 细胞系。
我们的数据表明，TLRs1、7、8 在 CRC 中上调，而在对照中下调。此外，与良性肿瘤和健康对照组相比，CRC 患者中有 3 个 miRNAs（-122、-29b 和 -15b）相对下调，而 4 个 miRNAs（-202、miRNA-98、-21 和 -let7i）上调。将下调的 miRNA 模拟物转染入 CRC 细胞系后，细胞数量和活力显著减少，TLRs1、7 和 8 的表达下调，下游效应物 IL6 蛋白减少，表明这些 miRNAs 是致癌作用的负调节剂。
microRNAs 可以作为 TLRs 的拮抗配体，限制炎症性肿瘤微环境。
