Expression and significance of Smac/DIABLO, XIAP mRNA in rats with acute pancreatitis / 中华胰腺病杂志

Objective To investigate the expression of Smac/DIABLO, XIAP mRNA in acute pancreatitis (AP) and the relationship with the severity in rats.Methods Fifty-four SD rats were randomly divided into three groups:sham-operation (SO) group, acute edematous pancreatitis (AEP) group and acute necrotizing pancreatitis (ANP) group.The models of AEP and ANP were induced by retrograde injection of 1％ and 3.5％ sodium deoxycholate into the pancreaticobiliary duct respectively.The specimens of pancreatic tissue at 3 h, 6 h, 12 h were collected, pathological changes of the pancreas were observed, apeptosis in pancreas were detected by TUNEL method and the expression of Smac/DIABLO, XIAP mRNA were analyzed by real-time PCR.Results Pathological changes of the pancreas confirmed the establishment of AEP and ANP.Apeptosis indexes in SO group, AEP group and ANP group were 0.67±0.82, 6.62 ±0.78 and 4.70 ±0.82, and the differences were significant (P< 0.05).The expression of Smac/DIABLO mRNA of AEP group increased with time, while the expression of ANP group decreased with time.Compared with SO group, Smac/DIABLO mRNA expressions at 6 h in AEP and ANP group were 2.41 ± 0.92 and 1.47± 0.53, and the differences were significant (P<0.05).By contrast, the expressions of XIAP mRNA in AEP group decreased with time,while the expressions in ANP group increased with time.The expressionsof XIAP mRNA at 6 h in AEP and ANP group were 5.51 ± 1.07 and 6.99 ± 1.00, and the differences were significant (P<0.05).Conclusions In acute pancreatitis, the expression of Smac/DIABLO mRNA was consistent with the apoptosis of pancreatic acinar cells, but not consistent with the severity of pancreatitis.The expression of XIAP mRNA was consistent with the severity of pancreatitis.Smac/DIABLO, XIAP mRNA is associated with regulation of apoptosis.

Smac/DIABLO and acute renal ischemia-reperfusion injury / 国际儿科学杂志

Ischemia-reperfusion after neonatal asphyxia is a key factor in renal injury,which often leads to apoptosis of tubular epithelial cells.Apoptosis is an important form of injury for renal tubular epithelial cells after asphyxia.Smac/DIABLO is released to the cytosol in response to diverse apoptotic stimuli while mitochondrial targeting signal peptide is removed.In the cytosol,Smac/DIABLO interacts and antagonizes inhibitors of apoptosis proteins,thus allowing the activation of caspases and apoptosis.And thus it increases the ischemia-reperfusion renal injury,leading to acute renal failure.

Infección por el virus de la Lengua azul: activación de señales celulares que inducen apoptosis / Bluetongue virus infection: signaling pathway activated during apoptosis

El virus de la Lengua azul (VLA) es un ARN virus de doble cadena que induce apoptosis tanto en cultivos celulares como en tejidos blanco. Con el fin de dilucidar el mecanismo de apoptosis en la infección por el VLA, en el presente trabajo examinamos en detalle, por la técnica de Western blot, las señales celulares de caspasas, Bax, citocromo c, Smac/DIABLO y factor nuclear kappa B (NF-kB) que se activan en la infección viral. Hemos comprobado que luego de la infección in vitro con el VLA, se detectó la activación de la caspasa 8 y con ello el mecanismo extrínseco de la apoptosis. También detectamos por primera vez no sólo la activación de miembros de la familia Bcl-2 (Bax), sino también la liberación del citocromo c y la proteína Smac/DIABLO, confirmando que en la infección por el VLA está involucrado el mecanismo secuencial intrínseco de la apoptosis. Asimismo, demostramos que la infección por el VLA activa el NF-kB y que la apoptosis es sustancialmente reducida mediante la inhibición del mismo. La activación de las señales celulares tales como Bax, citocromo c, Smac/DIABLO y NF-kB presentados en este trabajo, esclarecen los mecanismos apoptóticos durante la infección por el VLA para una mayor comprensión del papel primario que juega la apoptosis en la patogénesis del virus.

Bluetongue (BTV) is a double-stranded RNA virus that induces apoptosis both in mammalian cell cultures and in target tissues. To elucidate the apoptosis pathways in BTV infection, we have examined in detail the apoptosis mechanism by examination of caspases, Bax, cytochrome c, Smac/DIABLO and NF-kB signalling pathways. In this report, after cell infection with BTV, the activation of caspase 8 was detected, proving the extrinsic receptor binding apoptotic pathway. Apoptosis followed a sequential pathway involving the detection of activated Bcl-2 family members. Furthermore, its translocation to the mitochondria, as well as the release of cytochrome c and Smac/Diablo confirmed that BTV apoptosis involves the sequential intrinsic pathway. In addition, we demonstrated that NF-kB was activated following BTV infection and cell treatment with an inhibitor peptide before BTV infection, prevented NF-kB activation and substantially reduced cellular apoptosis. Our accumulating data concerning the activation of Bax, cytochrome c, Smac/DIABLO and NF-kB clarify the mechanism of apoptosis during BTV infection, and confer a better understanding of the primary role of apoptosis in BTV pathogenesis.

Synthetic Smac Peptide Enhances Chemo-sensitivity of Bladder Cancer Cells / 华中科技大学学报（医学）（英德文版）

The effects of synthetic Smac peptide (SmacN7) on chemotherapeutic sensitivity of bladder cancer cells were investigated. SmacN7 penetratin peptide was synthesized and delivered into T24 cells. MTT assay was used to evaluate the viability of T24 cells induced by low-dosage of MMC. Flow cytometry was used to analyze the proportions of apoptosis. Western blot was used to detect the expression of XIAP and Caspase-3. The activity of Caspase-3 was measured and the effect of SmacN7 combined with MMC on T24 cell lines was also determined. The results showed that SmacN7 penetratin peptide could successfully interact with endogenous XIAP, increase the proportions of apoptosis of T24 cell lines induced by low-dosage of MMC in a dose-and time-dependent manner. An obvious down-regulation of XIAP expression and up-regulation of Caspase-3 was identified by Western blot. The activity of Caspase-3 in experimental group was significantly increased as compared with that in the control group. As compared with MMC group, the viability of T24 cells in SmacN7 penetratin peptide + MMC group was markedly decreased to 2.22 and 3.61 folds at 24h and 48h respectively. It was concluded that SmacN7 penetratin peptide could act as a cell-permeable IAP inhibitor, inhibit the proliferation, induce apoptosis and enhance the chemo-sensitivity of bladder cancer cells to MMC. These findings indicate that SmacN7 penetratin peptide may be a very promising ageut for bladder cancer treatment when used in combination with chemotherapy.

Estudo da expressão de survivina e smac/diablo na leucemia mielóide crônica

Leucemia mielóide crônica (LMC) é uma doença mieloproliferativa com expansão clonal de células malignas. O cromossomo Philadelphia, derivado da translocação recíproca entre os cromossomos 9 e 22, resulta em um gene quimérico chamado BCR-ABL, encontrado em 90 (por cento) dos pacientes com LMC, sendo atribuída a essa quimera a patogênese da LMC. Imatinibe, um fármaco alvo-específico, liga-se e estabiliza a forma inativa da Bcr-Abl impedindo os efeitos da proteína. O desenvolvimento de resistência ao Imatinibe e a persistência de doença residual mínima tem desanimado os investigadores, além disso, respostas ao Imatinibe são menos freqüentes e mais curtas em pacientes que se encontram nos estágios mais avançados da LMC. Levando em conta que a resistência ao Imatinibe poder ser multifatorial, a identificação dos mecanismos de envolvidos na resistência pode levar a ganhos em sobrevida para os pacientes...

Experiment of promoting chemosensitivity of bladder cancer cell by synthetic Smac peptide / 中国癌症杂志

Background and purpose:Smac/DIABLO was the only apoptosis-related protein that could inhibit IAPs directly and simultaneously.The four amino-residual AVPI(Ala-Val-Pro-lie)in its N-terminal was the very important domain that could stimulate apoptosis.This study investigated the effect of synthetic Smac peptide (SmacN7) on chemotherapy sensitivity of bladder cancer cells.Methods:SmacN7 penetratin peptide was synthesized and delivered into T24 cells.MTT assay was adopted to evaluate the viability of T24 cells induced by low-dosage of MMC. Flow cytometry was applied to analyze the proportion of apoptosis and Western blot was used to detect the expression of XIAP and caspase-3;The activity of caspase-3 was measured and the effect of SmacN7 combined with MMC on T24 cell lines was also determined.Results:SmacN7 penetratin peptide could successfully interact with endogenous XIAP and increase the proportions of apoptosis of T24 cell lines induced by low-dosage of MMC in a dose-and time- dependent manner.An obvious down-regulation of XIAP expression and up-regulation of caspase-3 was identified by Western blot.The activity of caspase-3 in experimental group was significantly increased as compared with that in the control group;Combining the treatment with SmacN7 penetratin peptide,the viability of T24 cells decreased to 55% and 72.7% in 24 hrs and 48 hrs respectively.Conclusion:SmacN7 penetratin peptide could act as a cell-permeable IAP inhibitor,inhibit the proliferation,induce apoptosis and enhance the chemo-sensitivity of bladder cancer cells to MMC. When combined with chemotherapy,it may be a very promising strategy for bladder cancer therapy.

The effect of Smac/DIABLO associating with Survivin shRNA on the cell growth and apoptosis of Lovo / 中国癌症杂志

Background and purpose:The Smac/DIABLO(the second mitochondrial derived activator of caspase/direct IAP binding protein with low pI)is a new kind of mitochondria protein,it inhibits IAPs(inhibitors of apoptosis protein),including Survivin,and activates caspase-9 and caspase-3,accordingly promotes apoptosis.In this study,we investigated the effect of over-expressing mitochondrial protein-Smac/DIABLO while silencing inhibitor of apoptosis protein-Survivin on the cell growth,cell cycle and apoptosis of human colon cancer cells through cotransfecting both genes.Methods:Constructed survivin-shRNA-EGFP plasmid was transected with Smac-pcDNA3.1 plasmid into Lovo cells at either half each dose or total dose,respectively.Western blot was used to survey the protein level of Smac and Survivin;Hoechst 33258 staining was used to detect the karyomorphological diversity of apoptotic cells and evaluate apoptotic ratio roughly;PI staining and flow cytometry analysis were used to examine cell cycle;caspase-3 Detection Kits was used to detect the activity of caspase-3.Results:The expression of Smac protein increased but Survivin protein decreased 48 hr after transfection.Karyomorphological diversify of apoptotic cells were obviously observed by hoechst 33258 staining.The apoptosis rate in Smav+Survivin shRNA group was(18.5?1.7)%,which was higher than that in Smac group(9.6?1.8)% and Survivin shRNA group(15.0?0.3)%,and all of three groups were significantly higher than the control groups;The cells of G0/G1 phase increased to(51.0?6.2)% in Smac group,and the cells of S stage increased to(53.3?1.3)% in Survivin shRNA group(P