Suppressive RNA Research Articles

Exosomal microRNAs released from tumor cells can play a role as reliable non-invasive biomarkers in the diagnosis and prognosis of breast cancer

Breast cancer is one of the leading causes of death in women. Breast cancer develops from the milk-producing cells of the breast tissue. Exosomes from breast cancer cells have been linked to proliferation, metastasis, chemoresistance, and carcinogenesis, according to research. Exosomes are membrane-bound extracellular vesicles that can be secreted from cancer cells and contain a variety of contents such as nucleic acid, protein, lipid, etc. MicroRNAs, a component of exosomes, are small non-coding RNAs that dysregulate in various cancers and can function as oncogenic or suppressive RNA. MiRNAs influence cancer progression by binding to the 3' or 5' UTR (untranslated region) of their target. Because of their important role in cancer tumorigenesis, progression, and metastasis, some novel diagnostic and prognosis tools have been developed. In this study, we list some prominent exosomal microRNA, the key function of some specific exosomal miRNA, and their ability to act as a biomarker or a new therapy that they have been researching since 2020.

Sequences derived from self-RNA containing certain natural modifications act as suppressors of RNA-mediated inflammatory immune responses

The ability of the host to distinguish between self and foreign nucleic acids is one of the critical factors contributing to the recognition of pathogens by Toll-like receptors (TLRs). Under certain circumstances, eukaryotic self-RNA may reach TLR-containing compartments allowing for self-recognition. Specific modifications were previously demonstrated to suppress immune activation when placed at several positions in an immune stimulatory RNA or silencing RNA (siRNA). However, we show that even a simple natural modification such as a single 2'-O-methylation at different nucleotide positions throughout a sequence derived from a self-RNA strongly interferes with TLR-mediated effects. Such a single modification can even have an inhibitory effect in vitro and in vivo when placed in a different than the immune stimulatory RNA strand acting as suppressive RNA. Several safeguard mechanisms appear to have evolved to avoid cellular TLR-mediated activation by self-RNAs that may under other circumstances result in inflammatory or autoimmune responses. This knowledge can be used to include as few as a single 2'-O-methyl modification at a specific position in a siRNA sense or anti-sense strand to avoid TLR immune effects.