RESUMO
The aberrant expression of human sirtuin 2 (SIRT2) has been detected in various types of cancer; however, the biological roles, underlying mechanisms and clinical significance of SIRT2 dysregulation in human colorectal cancer (CRC) remain unclear. The results of this study demonstrate that compared with paired normal tissues, SIRT2 expression is significantly decreased in CRC tissues. SIRT2 loss has been correlated with clinicopathological characteristics, including distant metastasis, lymph node metastasis and American Joint Committee on Cancer (AJCC) stage; this loss serves as an independent factor that indicates a poor prognosis for patients with CRC. Further gain- and loss-of-function analyses have demonstrated that SIRT2 suppresses CRC cell proliferation and metastasis both in vivo and in vitro. Mechanistically, miR-212-5p was identified to directly target the SIRT2 3'-untranslated region (3'-UTR), leading to SIRT2 down-regulation. The ectopic expression of SIRT2 reverses the effect of miR-212-5p overexpression on CRC cell colony formation, invasion, migration and proliferation. Clinically, an inverse correlation was found between miR-212-5p and SIRT2 expression. High miR-212-5p expression has been found to result in a poor prognosis and aggressive clinicopathological characteristics in patients with CRC. Taken together, these results suggest that SIRT2, targeted by miR-212-5p, acts as a tumour suppressor in CRC and that the miR-212-5p/SIRT2 axis is a promising prognostic factor and potential therapeutic target in CRC.
Assuntos
Proliferação de Células/genética , Neoplasias Colorretais/genética , Metástase Linfática/genética , MicroRNAs/genética , Sirtuína 2/genética , Regiões 3' não Traduzidas/genética , Animais , Linhagem Celular Tumoral , Movimento Celular/genética , Neoplasias Colorretais/patologia , Regulação para Baixo/genética , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Genes Supressores de Tumor/fisiologia , Células HCT116 , Humanos , Metástase Linfática/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Estadiamento de Neoplasias/métodos , PrognósticoRESUMO
Production of structured lipid 1,3-dioleoyl-2-palmitoylglycerol (OPO), from tripalmitin (PPP) and oleic acid (OA) using lipases and ultrasonic pretreatment was conducted. Factors influencing both the ultrasonic conditions and enzymatic reaction were investigated. Optimum conditions could be attained with 6 min pretreatment time, 50% ultrasonic power, 3 s/9 s (work/pause) cycle of ultrasonic pulse, 1:8 PPP/OA molar ratio, 12% enzyme dosage and 50 °C temperature of. At the optimum conditions, the OPO yield of 51.8% could be achieved in 4h. Studies showed that the OPO content increased to 35.9% in 1h with ultrasonic pretreatment, in comparison to 4h without ultrasonic pretreatment. Reuse of Lipozyme RM IM for 10 cycles under ultrasonic irradiation did not cause essential damage to its lipase activity. Reaction kinetic model fitted well with the proposed Ping-Pong mechanism. The apparent kinetic constant (Vm'/K2) of ultrasound pretreatment reaction was 2.52 times higher than the conventional mechanical stirring, indicating that ultrasound pretreatment enhanced the substrates affinity to the enzyme. This study confirmed that ultrasonic pretreatment was more efficient in OPO production than conventional mechanical agitation.