RESUMEN
ObjectiveTo investigate the effect of curcumin on the cycle arrest of human colon cancer HCT116 cells and decipher the possible molecular mechanism. MethodThe methyl thiazolyl tetrazolium （MTT） method was employed to examine the effects of curcumin （0， 12.5， 25， 50， 75， 100 μmol·L-1） and 5-fluorouracil （5-FU， 600 μmol·L-1） on the proliferation of HCT116 cells at different time points （24， 48， 72 h）. Flow cytometry was employed to examine the cycle of HCT116 cells treated with curcumin （0， 25， 50， 75 μmol·L-1） and 5-FU. Western blot was employed to determine the expression of proteins in the Janus kinase 1 （JAK1）/signal transducer and activator of transcription 1 （STAT1） /cyclin-dependent kinase inhibitor 1A （p21） pathway in HCT116 cells. The binding of STAT1 to p21 promoter region was detected by chromatin immunoprecipitation （ChIP）. Small interfering RNA （siRNA） was employed to measure the role of STAT1 in regulating the expression of p21 and that of JAK1 in regulating the activation of STAT1 by Western blot and cellular immunofluorescence， respectively. ResultCompared with the blank group， the HCT-116 cells treated with curcumin and 5-FU showed decreased viability （P<0.05）， increased proportions of cells in the G0/G1 phase （P<0.05）， decreased proportions of cells in the S phase and G2/M phase （P<0.05）， down-regulated protein level of phosphorylated p21 （P<0.05）， and up-regulated protein level of p21 （P<0.05）. Compared with the curcumin group， the p21 siRNA+ curcumin group presented decreased proportion of cells in G0/G1 phase （P<0.05）. Compared with the blank group， curcumin elevated the level of phosphorylated STAT1 （p-STAT1） （P<0.05）. Compared with the curcumin group， the curcumin + STAT1 siRNA group showcased up-regulated protein level of p21 in HCT116 cells （P<0.05）. The mechanism study showed that curcumin treatment enhanced the enrichment of STAT1 in the p21 promoter region （P<0.05） compared with the blank group. Compared with the blank group， curcumin up-regulated the level of phosphorylated JAK1 （p-JAK1） （P <0.05）. Compared with the curcumin group， the curcumin + STAT1 siRNA group demonstrated up-regulated protein levels of p-STAT1 and p21 in HCT116 cells （P<0.05）. ConclusionCurcumin may induce the cycle arrest of human colon cancer HCT116 cells by activating the JAK1/STAT1/p21 signaling pathway.
RESUMEN
ObjectiveTo explore the molecular mechanism of "transmission between the lung and brain" of influenza based on Janus kinase 1/signal transducer and activator of transcription 1（JAK1/STAT1） signaling pathway and further investigate the intervention effect of Maxing Shigantang （MXSGT）. MethodA total of 100 SPF BALB/c mice were randomly divided into a normal group，a model group，an oseltamivir group （21.63 mg·kg-1·d-1），an antiviral granules group（3.9 g·kg-1·d-1）， and an MXSGT group（6.05 g·kg-1·d-1）， with 20 mice in each group. The pneumonia model was induced in mice except for those in the normal group by intranasal infection of influenza A virus（IAV）. Twenty-four hours after modeling，mice were treated with corresponding drugs， while those in the normal group and the model group received the same amount of normal saline by gavage， once a day for 3 and 7 days. The pathological changes in the lung and brain were observed by hematoxylin-eosin（HE）staining. The mRNA expression of IAV nucleoprotein（NP），JAK1， and STAT1 in the lung and brain was detected by real-time quantitative polymerase chain reaction（Real-time PCR）， and the protein expression of JAK1 and STAT1 in the lung and brain was detected by Western blot. Immunohistochemical method was used to detect the expression of phosphorylated（p）-STAT1 in the lung and brain tissues， and enzyme-linked immunosorbent assay（ELISA） was used to detect the serum levels of interleukin-1β（IL-1β） and interleukin-10（IL-10）. ResultCompared with the normal group， the model group showed obvious pathological changes in the lung tissues and cerebral cortex， increased relative mRNA expression of IAV NP in the lung （P<0.01）， elevated mRNA and protein expression of JAK1 and STAT1 in the lung and brain tissues （P<0.05，P<0.01），up-regulated expression level of p-STAT1 in lung tissues and cerebral cortex （P<0.05，P<0.01）， and increased serum level of IL-1β （P<0.05）. Compared with the model group， the MXSGT group showed alleviated pathological damage to lung tissues and cerebral cortex， decreased relative mRNA expression of IAV NP in lung tissues（P<0.01），reduced mRNA and protein expression levels of JAK1 and STAT1 in lung tissues and brain tissues（P<0.05，P<0.01）， and increased serum level of IL-10（P<0.01）. ConclusionThe abnormal activation of the JAK1-STAT1 signaling pathway may be one of the molecular mechanisms of "transmission between the lung and brain" of influenza. As an effective compound prescription against the influenza virus，MXSGT can alleviate the pathological damage of brain tissues in mice infected with IAV by regulating the level of cytokines mediated by this pathway.