Synthetic Circular miR-21 Sponge as Tool for Lung Cancer Treatment Rama Ballesteros, Ana Rosa Quiñonero Muñoz, Francisco José Mesas Hernández, Cristina Melguizo Alonso, Consolación Prados Salazar, José Carlos miRNA Circular sponges miRNA-21 Lung cancer This work was funded by the CTS-107 Group. This work was also partially supported by a grant from the Instituto de Salud Carlos III (ISCIII) (project PI19/01478) (FEDER). Lung cancer is the most common cancer in the world and several miRNAs are associated with it. MiRNA sponges are presented as tools to inhibit miRNAs. We designed a system to capture miRNAs based on circular RNAs (circRNA). To demonstrate its usefulness, we chose miR-21, which is upregulated and implicated in lung cancer. We constructed a miR-21 sponge and inserted it into a vector that facilitates circular RNA production (Circ-21) to study its effect on growth, colony formation, and migration in lung cancer cell lines and multicellular tumor spheroids (MTS). Circ-21 induced a significant and time-dependent decrease in the growth of A549 and LL2 cells, but not in L132 cells. Furthermore, A549 and LL2 cells transfected with Circ-21 showed a lower number of colonies and migration than L132. Similar findings were seen in A549 and LL2 Circ-21 MTS, which showed a significant decrease in volume growth, but not in L132 Circ-21 MTS. Based on this, the miR-21 circular sponge may suppress the processes of tumorigenesis and progression. Therefore, our system based on circular sponges seems to be effective, as a tool for the capture of other miRNAs. 2022-04-20T11:54:14Z 2022-04-20T11:54:14Z 2022-03-09 info:eu-repo/semantics/article Rama, A.R... [et al.]. Synthetic Circular miR-21 Sponge as Tool for Lung Cancer Treatment. Int. J. Mol. Sci. 2022, 23, 2963. [https://doi.org/10.3390/ijms23062963] http://hdl.handle.net/10481/74404 10.3390/ijms23062963 eng http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España MDPI