RESUMO
Sorafenib resistance remains a major obstacle for the effective treatment of hepatocellular carcinoma (HCC), and a number of miRNAs contribute to this resistance. However, the regulatory networks of miRNAs are very complex, thus inhibiting a single miRNA may sequentially activate other compensatory pathways. In the present study, we generated an artificial long non-coding RNA (AlncRNA), which simultaneously targets multiple miRNAs including miR-21, miR-153, miR-216a, miR-217, miR-494 and miR-10a-5p. These miRNAs have been shown to be upregulated in sorafenib-resistant cells and participate in the mechanisms underlying sorafenib resistance. The AlncRNA contains tandem sequences of 6 copies of the complementary binding sequences to the target miRNAs and is expressed by an adenoviral vector (Ad5-AlncRNA). Infection of Ad5-AlncRNA into sorafenib-resistant HCC cells blocked the function of miRNAs, and sequentially inhibited the downregulation of PTEN and activation of AKT. Ad5-AlncRNA significantly inhibited proliferation and induced apoptosis of sorafenib-resistant cells and enhanced the effects of sorafenib in vitro and in animal models. Inhibition of autophagy decreased the sensitivity of sorafenib-resistant cells to Ad5-AlncRNA, while its induction had the opposite effect. These results indicate that targeting multiple miRNAs by the artificial lncRNA could be a potential promising strategy for overcoming sorafenib resistance in the treatment of HCC.
Assuntos
Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , MicroRNAs/genética , Niacinamida/análogos & derivados , Compostos de Fenilureia/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Interferência de RNA , RNA Longo não Codificante/genética , Adenoviridae/genética , Animais , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Vetores Genéticos/genética , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Niacinamida/farmacologia , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sorafenibe , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Daidzein belongs to the group of isoflavones, found in a wide variety of plant-derived foods, especially in soybeans and soy-based foods. In this study, the effect of daidzein on human gastric carcinoma cells (BGC-823) and its mechanism were investigated. MTT assay was applied in the detection of the inhibitory effects of daidzein on cell proliferation. Hoechst-propidium iodide staining and flow cytometry were used to examine the apoptosis as well as the mitochondrial transmembrane potential. Western blotting was performed to detect the expression of apoptosis-associated proteins: cleaved PARP, cleaved caspase-9, cleaved caspase-3, Bcl-2, and Bax. Daidzein significantly inhibited the growth and proliferation of human gastric carcinoma cells (BGC-823) in a concentration- and time-dependent manner. Furthermore, it was found that an insult of daidzein to BGC-823 cells caused them to die by disruption of mitochondrial transmembrane potential, demonstrated not only by staining dead cells for phosphatidylserine but also by the up-regulation (cleaved PARP, cleaved caspase-9, cleaved caspase-3, Bax) and down-regulation (Bcl-2) of proteins associated with apoptosis and survival; whereas, the pan-caspase inhibitor z-VAD-fmk could partially rescue cells against damage of daidzein. Taken together, the results of this study demonstrate that daidzein significantly induces apoptosis via a mitochondrial pathway. Specifically, daidzein induced a change in the Bax/Bcl-2 ratios and activation of caspases-3 and -9 and the cleavage of PARP. Therefore, daidzein has the potential for use as a therapeutic agent for the treatment of gastric carcinoma.