RESUMO
AIMS: The adenosine-to-inosine (A-to-I) RNA editing controlled by the editing genes are known to diversify transcripts in human. Aberrant A-to-I editing due to dysregulation of the editing genes are involved in cancer development. However, it is still largely unclear how single nucleotide polymorphisms (SNPs) in the A-to-I editing genes confer to recurrence and/or drug resistance of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) therapy in non-small-cell lung cancer (NSCLC). MATERIALS AND METHODS: In this study, we systematically evaluated and validated the role of twenty-eight potential functional genetic variants in four A-to-I editing genes (ADAR, ADARB1, ADARB2 and AIMP2) in prognosis of NSCLC patients receiving EGFR-TKIs. KEY FINDINGS: We identified the ADAR rs1127309, rs1127317, and rs2229857 SNPs markedly contributing to prognosis of patients treated with EGFR-TKIs. Interestingly, SNP rs1127317 locating in the ADAR 3'-untranslated region regulates gene expression in an allele-specific manner via modulating binding of miR-454-5p in cells. In support of this, patients with the rs1127317 C allele correlated with elevated ADAR expression in tumors showed profoundly shorten survival after EGFR-TKIs therapy compared to the A allele carriers. Silencing of ADAR notably enhanced gefitinib sensitivities of NSCLC cells. SIGNIFICANCE: Our findings highlight the importance of the A-to-I RNA editing in drug resistance and nominate ADAR as a potential therapeutic target for unresectable NSCLC.
Assuntos
Adenocarcinoma de Pulmão/genética , Adenosina Desaminase/genética , Antineoplásicos/farmacologia , Neoplasias Pulmonares/genética , Inibidores de Proteínas Quinases/farmacologia , Proteínas de Ligação a RNA/genética , Regiões 3' não Traduzidas , Adenocarcinoma de Pulmão/tratamento farmacológico , Adenocarcinoma de Pulmão/mortalidade , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Resistencia a Medicamentos Antineoplásicos/genética , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Gefitinibe/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/mortalidade , Proteínas Nucleares/genética , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Endotoxin removal is essential for the safety of biological products. To remove endotoxin efficiently, we used polymyxin B (PMB) affinity adsorbent to remove endotoxin from protein solutions by static adsorption. We studied the effects of spacer length and ligand density of the affinity adsorbent, pH, salt type and concentration, protein type and concentration, endotoxin concentration, and additive on endotoxin removal and protein recovery. Endotoxin content and protein concentration were determined by test and Lowry assay respectively. The results showed that PMB affinity adsorbent had high capacity, high adsorption speed, high removal efficiency and good reusability. In addition, ligand density, pH, salt concentration and the isoelectric point and hydrophobicity of protein all had remarkable influence on the endotoxin removal. Under the optimal conditions, the recoveries of hemoglobin, human serum albumin and lysozyme were 87.2%, 73.4% and 97.3%, respectively, and the corresponding endotoxin removal rates 99.8%, 97.9% and 99.7%, respectively. This study illustrated the effects of solution conditions on the efficiency of endotoxin removal and protein recovery, and would provide useful reference for the efficient removal of endotoxin from biological products.