RESUMO
The dysregulation of microRNAs (miRNAs) has been demonstrated to contribute to drug resistance of cancer cells, and sustained nuclear factor (NF)κB activation is also pivotal in tumor resistance to chemotherapy. In the present study, an essential role for miRNA (miR)-20a was identified in the regulation of gastric cancer (GC) chemoresistance. The expression level of miR20a was assayed by reverse transcriptionquantitative polymerase chain reaction. Additionally, 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide was used to detect the drugresistance phenotype changes of cancer cells associated with upregulation or downregulation of miR20a. Protein expression levelss were measured by western blotting and immunohistochemistry. Flow cytometry was used to detect cisplatininduced apoptosis. It was found that miR20a was markedly upregulated in GC plasma and tissue samples. Additionally, miR20a was upregulated in GC plasma and tissues from patients with cisplatin (DDP) resistance, and in the DPPresistant gastric cancer cell line (SGC7901/DDP). The expression of miR20a was inversely correlated with the expression of cylindromatosis (CYLD). Subsequently, the assessment of luciferase activity verified that CYLD was a direct target gene of miR20a. Treatment with miR20a inhibitor increased the protein expression of CYLD, downregulated the expression levels of p65, livin and survivin, and led to a higher proportion of apoptotic cells in the SGC7901/DDP cells. By contrast, ectopic expression of miR20a significantly repressed the expression of CYLD, upregulated the expression levels of p65, livin and survivin, and resulted in a decrease in the apoptosis induced by DDP in the SGC7901 cells. Taken together, the results of the present study suggested that miR20a directly repressed the expression of CYLD, leading to activation of the NFκB pathway and the downstream targets, livin and survivin, which potentially induced GC chemoresistance. Altering miR20a expression may be a potential therapeutic strategy for the treatment of chemoresistance in GC in the future.
Assuntos
Antineoplásicos/farmacologia , Cisplatino/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , MicroRNAs/genética , Interferência de RNA , Neoplasias Gástricas/genética , Proteínas Supressoras de Tumor/genética , Regiões 3' não Traduzidas , Proteínas Adaptadoras de Transdução de Sinal/genética , Idoso , Apoptose/efeitos dos fármacos , Apoptose/genética , Sítios de Ligação , Estudos de Casos e Controles , Linhagem Celular Tumoral , Proliferação de Células , Enzima Desubiquitinante CYLD , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Proteínas Inibidoras de Apoptose/genética , Masculino , Pessoa de Meia-Idade , NF-kappa B/metabolismo , Proteínas de Neoplasias/genética , SurvivinaRESUMO
Drug resistance of cancer cells can be regulated by the dysregulated miRNAs, and sustained NFκB activation also plays an important role in tumor resistance to chemotherapy. Here, we sought to investigate whether there was a correlation between miR-20a and the NFκB pathway to clarify the effects that miR-20a exerted on gastric cancer (GC) chemoresistance. We found that miR-20a was significantly upregulated in GC plasma and tissue samples. In addition, it was upregulated in GC plasma and tissues from patients with cisplatin-resistant gastric cancer cell line SGC7901/cisplatin (DDP). And the upregulation of miR-20a was concurrent with the downregulation of NFKBIB (also known as IκBß) as well as upregulation of p65, livin, and survivin. The luciferase activity suggested that NFKBIB was the direct target gene of miR-20a. Transfection of miR-20a inhibitor could increase NFKBIB level; downregulate the expression of p65, livin, and survivin; and lead to a higher proportion of apoptotic cells in SGC7901/DDP cells. Conversely, ectopic expression of miR-20a dramatically decreased the expression of NFKBIB; increased the expression of p65, livin, and survivin; and resulted in a decrease in the apoptosis induced by DDP in SGC7901 cells. Taken together, our findings suggested that miR-20a could promote activation of the NFκB pathway and downstream targets livin and survivin by targeting NFKBIB, which potentially contributed to GC chemoresistance.
Assuntos
Antineoplásicos/química , Cisplatino/química , Resistencia a Medicamentos Antineoplásicos , Proteínas I-kappa B/metabolismo , MicroRNAs/metabolismo , Neoplasias Gástricas/patologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Apoptose , Linhagem Celular Tumoral/efeitos dos fármacos , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Humanos , Proteínas Inibidoras de Apoptose/metabolismo , MicroRNAs/genética , Proteínas de Neoplasias/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Survivina , Fator de Transcrição RelA/metabolismo , Regulação para CimaRESUMO
BACKGROUND: MicroRNA-21 (miR-21) is highly expressed in the plasma of colorectal cancer (CRC) patients. Thus, miR-21 may be a useful novel diagnostic biomarker for CRC. This meta-analysis aims to verify the diagnostic value of circulating miR-21 in CRC patients. METHODS: A literature search was conducted for publications that evaluated the diagnostic value of miR-21 for CRC. The quality of each study was scored with the Quality Assessment of Diagnostic Accuracy Studies. The bivariate meta-analysis model was employed to summarize the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). Receiver operating characteristic curves were used to check the overall test performance. RESULTS: Five publications with six studies involving 579 patients and 266 controls were included in this meta-analysis. The pooled sensitivity was 77.4% [95% confidence interval (CI): 67.2%-85.1%], specificity was 84.6% (95% CI: 79.7%-88.5%), PLR was 5.02 (95% CI: 3.73-6.75), NLR was 0.27 (95% CI: 0.18-0.40), and DOR was 18.77 (95% CI: 10.41-33.83). The area under the summary ROC curve was 0.86. In addition, the results became prominent in the CRC group when a study that explored the advanced adenoma was excluded. CONCLUSION: Circulating miR-21 may be a suitable diagnostic biomarker for CRC with moderate sensitivity and specificity. Further studies should evaluate the diagnostic value of miR-21 for CRC in the future.
