MiRNAs in cancer

MicroRNAs (miRs) are small non-coding RNAs constituted by 20 nucleotides and present in diverse species, from microorganisms to humans, where their principal function is regulating diverse cellular processes.

The discovery of miRs occurred in 1993 with the identification of two miRs: the miR-lin-4 and the miR-let-7 in C. elegans. However, only in 2001 was the term miR introduced in the scientific community, as a nomenclature for these small molecules.

With the increasing investigation of these small molecules, it becomes clear that they regulate different genes involved in the development of various diseases, including cancer. They have been involved in all of the cancer development processes, namely proliferation, invasion, angiogenesis, and metastasis processes, demonstrating an aberrant expression in tumor tissues.

MiRs altered expression is then exacerbated in cancer patients, easily detected in biological samples such as blood, urine, saliva, and stool, and can be used in clinical settings.

The most common applications of miRs are as biomarkers for treatment prediction, diagnosis of neoplasia, and prognosis, used in various types of tumors. A commonly used miR in the clinic is miR-21, which is involved in different clinical trials and is studied in particular in the diagnosis of colorectal cancer, as a predictor of treatment in ovarian cancer, and as a prognostic biomarker for breast cancer.

These small molecules prove to be highly powerful regulators and have a lot of potential to help cancer patients.

Daniela Rocha Santos

References

Detassis, S., Grasso, M., Del Vescovo, V., & Denti, M. A. (2017). microRNAs Make the Call in Cancer Personalized Medicine. Front Cell Dev Biol, 5, 86. https://doi.org/10.3389/fcell.2017.00086 

Liz, J., & Esteller, M. (2016). lncRNAs and microRNAs with a role in cancer development. Biochimica et Biophysica Acta 1859(1), 169-176. https://doi.org/10.1016/j.bbagrm.2015.06.015 

Pritchard, C. C., Cheng, H. H., & Tewari, M. (2012). MicroRNA profiling: approaches and considerations. Nat Rev Genet, 13(5), 358-369. https://doi.org/10.1038/nrg3198 

Santos, D. A. R., Gaiteiro, C., Santos, M., Santos, L., Dinis-Ribeiro, M., & Lima, L. (2023). MicroRNA Biomarkers as Promising Tools for Early Colorectal Cancer Screening-A Comprehensive Review. Int J Mol Sci, 24(13). https://doi.org/10.3390/ijms241311023 

Szczepanek, J., Skorupa, M., & Tretyn, A. (2022). MicroRNA as a Potential Therapeutic Molecule in Cancer. Cells, 11(6). https://doi.org/10.3390/cells11061008