MicroRNAs (miRNAs) are small non-coding RNA molecules, approximately 22 nucleotides in length that regulate gene translation through silencing or degradation of target mRNAs. They are involved in multiple biological processes, including differentiation and proliferation, metabolism, hemostasis, apoptosis or inflammation, and in pathophysiology of many diseases. Numerous studies have suggested circulating miRNAs as promising diagnostic and prognostic biomarkers of many diseases.
MiR-26b is located in an intron of the Ctdsp2 gene and it can regulate neuronal differentiation together with its host gene. MiR-26b has been reported to be a critical regulator in carcinogenesis and tumor progression by acting as a tumor suppressor gene in various types of cancer. It has been found that miR-26b is downregulated in breast cancer and that it can inhibit cellular proliferation. Down-regulation of miR-26b in osteosarcoma increased the levels of CTGF and Smad1, facilitating osteosarcoma metastasis. MiR-26b could also modulate non-small cell lung cancer chemoresistance and migration through its association with PTEN. In addition, a recent study demonstrated that miR-26b-5p suppresses proliferation, migration and invasion of intrahepatic cholangiocarcinoma cells by suppressing S100A7. Similarly, downregulation of miR-26b-5p together with miR-26a-5p was frequently observed in bladder cancer cells, and both of these miRNAs significantly inhibited cancer cell migration and invasion.
Besides cancer, aberrant expression and functional abnormalities of miR-26b have been reported in a variety of other diseases. The results suggest that miR-26b plays a role in maintenance of heart function by regulating Wnt pathway.
miR-26 has been observed to be upregulated in the human temporal cortex in Alzheimer's disease and in APP/PS1 double-transgenic mice, suggesting that miR-26b may function in development of Alzheimer's disease.
Summary References (10)
References to miR-26b-5p
Dill, Holger, et al. "Intronic miR-26b controls neuronal differentiation by repressing its host transcript, ctdsp2." Genes & development 26.1 (2012): 25-30.
Liu, Hong, et al. "MicroRNA 26b is upregulated in a double transgenic mouse model of Alzheimer's disease and promotes the expression of amyloid β by targeting insulin like growth factor 1." Molecular medicine reports 13.3 (2016): 2809-2814.
Li, Jia, et al. "MiRNA-26b inhibits cellular proliferation by targeting CDK8 in breast cancer." International journal of clinical and experimental medicine 7.3 (2014): 558.
Duan, Guoqing, et al. "MicroRNA-26b inhibits metastasis of osteosarcoma via targeting CTGF and Smad1." Tumor Biology 36.8 (2015): 6201-6209.
Liang, Naixin, et al. "Down-regulation of microRNA-26b modulates non-small cell lung cancer cells chemoresistance and migration through the association of PTEN." Acta Biochim Biophys Sin 47.7 (2015): 530-538.
Fan, Fei, et al. "MicroRNA-26b-5p regulates cell proliferation, invasion and metastasis in human intrahepatic cholangiocarcinoma by targeting S100A7." Oncology letters 15.1 (2018): 386-392.
Miyamoto, K., et al. "Tumour-suppressive miRNA-26a-5p and miR-26b-5p inhibit cell aggressiveness by regulating PLOD2 in bladder cancer." British journal of cancer 115.3 (2016): 354.
Wu, Ke, et al. "miRNA 26a 5p and miR 26b 5p inhibit the proliferation of bladder cancer cells by regulating PDCD10." Oncology reports 40.6 (2018): 3523-3532.
Wang, Duo, et al. "Impact of miR‐26b on cardiomyocyte differentiation in P19 cells through regulating canonical/non‐canonical Wnt signalling." Cell proliferation 50.6 (2017): e12371.
Absalon, Sabrina, et al. "MiR-26b, upregulated in Alzheimer's disease, activates cell cycle entry, tau-phosphorylation, and apoptosis in postmitotic neurons." Journal of Neuroscience 33.37 (2013): 14645-14659.