CELL-INTERNALIZATION SELEX METHOD FOR SPECIFIC RNA APTAMER SELECTION AGAINST ACUTE LYMPHOBLASTIC LEUKEMIA CELLS

VARGAS, M.; GIANGRANDE, P.; RUIZ CIANCIO, D.; BRUNO, M.A.; COIRINI, H.; MESTRE GIMENEZ, M.B.

CABA

Congreso; Reunion Conjunta de Sociedades de Biociencias; 2017

SAIC-SAIB-SAB-y otras sociedades

Acute lymphoblastic leukemia (ALL) is amalignant disorder characterized by clonal proliferation of early B- and T-lymphocyte progenitors. ALL is the most frequent cancer in pediatric oncology.Aptamers are single stranded DNA or RNA oligonucleotides that could targetcancer cells with high affinity and specificity. Even more, they couldinternalize into the target cell. Unlike antibodies, aptamers have lowimmunogenicity and they are easily synthesized and modified. Furthermore, thesmaller size of aptamers facilitates better tissue penetration what improvestheir clinical applicability. B-cell leukemia represents 80% of ALL cases,however, there is still no aptamer against B-ALL cells in the literature.Therefore, we aimed to select the first aptamer that specifically target andinternalize into B-ALL cells, without binding normal blood cells. To achievethis goal, we adapted the cell-internalization SELEX method for suspension celllines. In this new protocol, the starting RNA aptamer library was incubatedwith nontarget cells (Ea.Hy926 (human endothelial cells), JURKAT (T-ALL) andperipheral white blood cells of healthy patients). Those RNAs that do not bindor internalize into the nontarget cells were then transferred to the targetcells: B-ALL cells (KOPN-8 and NALM-16). Unbound and surface-bound RNAs werewashed off and only internalized sequences were recovered from the cancer cells.The recovered RNAs are amplified using RT-PCR and the resulting amplified dsDNAin vitro transcribed for the subsequent round of selection. After a total of 8selection rounds, we include NGS (Next Generation Sequencing) technology forthe bioinformatic analysis of the aptamers obtained. Subsequently, the aptamersfound were tested individually for internalization to find the best candidate tobe used as a delivery tool. Thus, these novel results could be useful foraptamer-mediated drug delivery that could provide a new therapeutic tool forthis disease. Keywords: Acute lymphoblastic leukemia, cell-SELEX, aptamer.