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Objective:To screen and characterize aptamers against BCR-ABL fusion protein.Methods:A 90bp single stranded DNA( ssDNA) random library was subjected to 13 rounds of selection against BCR-ABL fusion protein by systematic evolution of ligands by expotential enrichment ( SELEX ) method, the selected aptamers were cloned and sequenced.The primary sequences and structure of aptamers were analyzed by Clustal W and DNA Folding Sever and the percentage of the ssDNA pool bound to BCR-ABL core protein were determinated.Results: after 13 rounds selection, the percentage of ssDNA pool bound to BCR-ABL fusion protein increased from 0.3%to 47.1%,the results showed that affinities of the Aptamers were different,the second structure analysis revealed possible stem-loops for binding to BCR-ABL fusion protein,the affinity of aptamer A2 to BCR-ABL fusion protein was highest with Kd values as low as 72 nmol/L.Conclusion:Aptamers against BCR-ABL fusion protein has been identified by SELEX methods from a 90 bp single stranded DNA library.And provide certain reference for the clinical treatment of chronic myelogenous.
RESUMO
Aim Drug resistance is one of the major hinders on cancer treatments. α-enolase ( eno1 ) was closely related to the generation and development of drug resistance. This article aims to study the effect of eno1 on cell growth and drug resistance in human chro-nic myeloid leukemia cell line K562/A02 . Methods We screened three eno1 stable silencing cells K562/A02-sheno1 and its control cells K562/A02-shcon. Cell count assay was performed to test cell growth, MTT assay was used to test cell proliferation, flow cytometry was used to test the intra-cellular Rho123 content, the expression of genes were tested by real-time PCR assay and western blot assay on mRNA level and protein level, respectively. Results eno1 was o-ver-expressed in K562/A02 cells and its expression was increased by ( 2. 85 ± 0. 56 ) times and ( 1. 43 ± 0. 05 ) times on mRNA level and protein level com-pared to K562 cells. However, there was no difference in cell growth rate between K562/A02 cells and K562 cells. K562/A02-sheno1 cells showed lower cell growth rate and higher drug sensitivity to anti-cancer drugs taxol and doxorubicin. Moreover the Rho123 content was increased in K562/A02-sheno1 cells. The expression of MDR1 decreased in both mRNA level and protein level in K562/A02-sheno1 cells. Conclusion eno1 silencing could suppress cell growth, reverse drug resistance and increase its drug sensitivity in K562/A02 cells, and the mechanism was associated with the MDR1 gene.