RESUMO
The development of multidrug resistance (MDR) is a crucial cause of therapy failure in gastric cancer, which results in disease recurrence and metastasis. Long non-coding RNAs (lncRNAs) have been proven to be critical in carcinogenesis and metastasis of gastric cancer. However, little is known about the roles of ANRIL (antisense non-coding RNA in the INK4 locus) in gastric cancer MDR. The aim of our study is to identify the biological function of ANRIL in gastric cancer MDR. In our results, ANRIL was highly expressed in gastric cancer tissues of cisplatin-resistant and 5-fluorouracil (5-FU)-resistant patients, and the same upregulation trends were observed in cisplatin-resistant cells (BGC823/DDP) and 5-FU-resistant cells (BGC823/5-FU). In addition, BGC823/DDP and BGC823/5-FU cells transfected with ANRIL siRNA and treated with cisplatin or 5-FU, respectively, exhibited significant lower survival rate, decreased invasion capability, and high percentage of apoptotic tumor cells. The influence of ANRIL knockdown on MDR was assessed by measuring IC50 of BGC823/DDP and BGC823/5-FU cells to cisplatin and 5-FU, the result showed that silencing ANRIL decreased the IC50 values in gastric cancer cells. Moreover, qRT-PCR and western blotting revealed that ANRIL knockdown decreased the expression of MDR1 and MRP1, both of which are MDR related genes; regression analysis showed that the expression of ANRIL positively correlated with the expression of MDR1 and MRP1, resprectively In summary, knockdown of lncRNA ANRIL in gastric cancer cells inhibits the development of MDR, suggesting an efficacious target for reversing MDR in gastric cancer therapy.
Assuntos
Resistência a Múltiplos Medicamentos/genética , Resistencia a Medicamentos Antineoplásicos/genética , Inativação Gênica/fisiologia , RNA Longo não Codificante/genética , Neoplasias Gástricas/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/genética , Linhagem Celular Tumoral , Cisplatino/administração & dosagem , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Fluoruracila/administração & dosagem , Inativação Gênica/efeitos dos fármacos , Humanos , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Recidiva Local de Neoplasia/genética , RNA Interferente Pequeno , Estômago/efeitos dos fármacos , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/patologia , Taxa de Sobrevida , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genéticaRESUMO
Three pepsinogens (PG1, PG2, PG3) were highly purified from the stomach of Japanese seabass (Lateolabrax japonicus) by ammonium sulfate fractionation, DEAE-Sephacel anion exchange column chromatography and Sephacryl S-200 gel-filtration. Two dimensional polyacrylamide gel electrophoresis (2D-PAGE) analysis revealed that the molecular masses of the three PGs were 35, 37, and 34kDa, and their isoelectric points were 5.3, 5.1, and 4.7, respectively. Zymography analysis showed that the three pepsinogens had different mobilities and enzymatic activities under native conditions. Pepsinogens converted into their active form pepsins under pH 2.0 by one-step pathway or stepwise pathway. All three pepsins were completely inhibited by pepstatin A, a typical aspartic proteinase inhibitor. The N-terminal amino acid sequences of the three pepsinogens were determined to the 30th, 30th and 28th amino acid residue and those of their corresponding active form pepsins were also determined to the 19th, 18th and 20th amino acid residue, respectively. All amino acid sequences of Japanese seabass PGs revealed high identities to reported fish and mammalian pepsinogens. The effective digestion of fish and shrimp muscular proteins by pepsins indicated their physiological function in the degradation of food proteins.
