Effect of CDK1 Interferes with the Regulation of PLK1, Aurora B and TRF1 on the Proliferation of Leukemia Cells / 中国实验血液学杂志

OBJECTIVE@#To investigate the clinical characteristics, diagnosis and treatment of 1 case EBV negative extranodal NK/T cell lymphoma (ENKTL) patients.@*METHODS@#The clinical manifestations, diagnosis and treatment of one case ENKTL patients with EBV negative were analyzed retrospectively.@*RESULTS@#A 46-year-old woman diagnosed as positive for exosanal NK/T cell lymphoma (EBER@*CONCLUSION@#EBV negative ENKTL is rare in clinic and easy to be misdiagnosed, so it should be distinguished from peripheral T cell lymphoma. This case was treated with EBV positive ENKTL regimen, with good short-term efficacy.

Effect of CDK1 Interferes with the Regulation of PLK1, Aurora B and TRF1 on the Proliferation of Leukemia Cells / 中国实验血液学杂志

OBJECTIVE@#To investigate the effect of CDK1 interference regulation of PLK1, Aurora B and TRF1 on the proliferation of leukemia cells.@*METHODS@#The human myelogenous leukemia cell line HL-60 was selected as the research object, and the effect of TRF1 expression and its changes on cell proliferation and cycle was investigated by regulating intracellular CDK1 expression. The objects were divided into 5 groups, including control group, shRNA-NC group, CDK1-shRNA group, pcDNA group and pcDNA-CDK1 group. RT-PCR was used to detect the CDK1 expression of cells in each group; colony formation was used to detect the proliferation of the cells. Western blot was used to detect the expression of CDK1, PLK1, Aurora B, TRF1, and cyclin p53, p27, cyclinA.@*RESULTS@#The phosphorylation level of PLK1, Aurora B and the expression of TRF1 in the CDK1-shRNA group were significantly down-regulated as compared with those in the control group (P<0.05). Compared with the control group, the cells in CDK1-shRNA group showed lower clone formation rate, the increasing of cycle-associated proteins p53 and p27 and the decreasing of cyclinA expression (P<0.05). It was shown that interfered CDK1 expression could inhibit the proliferation of HL-60 cells and prolong the time that they enter mitosis, thereby extending the cell cycle. Compared with the control group, the overexpressed CDK1 in the pcDNA-CDK1 group made the phosphorylation level of PLK1, Aurora B, and TRF1 expression increase significantly (P<0.05), also the colony formation rate (P<0.05). The cycle-related proteins p53 and p27 was down-regulated, while cyclinA expression was up-regulate significantly (P<0.05). The results indicted that overexpressed CDK1 could stimulate adverse reactions, thereby promoting the proliferation of HL-60 cells and shortening the cell cycle.@*CONCLUSION@#Knocking out CDK1 can inhibit the phosphorylation of PLK1 and Aurora B and negatively regulate TRF1, thereby inhibiting the proliferation of leukemia cells.

Helicobacter pylori inhibited cell proliferation in human periodontal ligament fibroblasts through the Cdc25C/CDK1/cyclinB1 signaling cascade

PURPOSE: Several studies have shown that the oral cavity is a secondary location for Helicobacter pylori colonization and that H. pylori is associated with the severity of periodontitis. This study investigated whether H. pylori had an effect on the periodontium. We established an invasion model of a standard strain of H. pylori in human periodontal ligament fibroblasts (hPDLFs), and evaluated the effects of H. pylori on cell proliferation and cell cycle progression. METHODS: Different concentrations of H. pylori were used to infect hPDLFs, with 6 hours of co-culture. The multiplicity of infection in the low- and high-concentration groups was 10:1 and 100:1, respectively. The Cell Counting Kit-8 method and Ki-67 immunofluorescence were used to detect cell proliferation. Flow cytometry, quantitative real-time polymerase chain reaction, and western blots were used to detect cell cycle progression. In the high-concentration group, the invasion of H. pylori was observed by transmission electron microscopy. RESULTS: It was found that H. pylori invaded the fibroblasts, with cytoplasmic localization. Analyses of cell proliferation and flow cytometry showed that H. pylori inhibited the proliferation of periodontal fibroblasts by causing G2 phase arrest. The inhibition of proliferation and G2 phase arrest were more obvious in the high-concentration group. In the low-concentration group, the G2 phase regulatory factors cyclin dependent kinase 1 (CDK1) and cell division cycle 25C (Cdc25C) were upregulated, while cyclin B1 was inhibited. However, in the high-concentration group, cyclin B1 was upregulated and CDK1 was inhibited. Furthermore, the deactivated states of tyrosine phosphorylation of CDK1 (CDK1-Y15) and serine phosphorylation of Cdc25C (Cdc25C-S216) were upregulated after H. pylori infection. CONCLUSIONS: In our model, H. pylori inhibited the proliferation of hPDLFs and exerted an invasive effect, causing G2 phase arrest via the Cdc25C/CDK1/cyclin B1 signaling cascade. Its inhibitory effect on proliferation was stronger in the high-concentration group.

Development of a Novel Nonradioisotopic Assay and Cdc25B Overexpression Cell Lines for Use in Screening for Cdc25B Inhibitors

PURPOSE: The cyclin-dependent kinase 1 (Cdk1) and cyclin B complex performs important roles in the transition from the G2 to M phase in the cell cycle through removal of inhibitory phosphates on Cdk1, and Cdc25B, which is a dual-specific phosphatase, mediates these dephosphorylation events. However, measuring Cdc25B activity by existing methods is hampered by inadequate nonspecific substrates and the need to use a radiolabeled isotope. The present study aimed to develop an improved method with which to properly measure Cdc25B activity using a novel nonradioisotopic assay and Cdc25B overexpression cell lines. MATERIALS AND METHODS: A nonradioisotopic Cdk1 kinase assay, based on Western blotting for retinoblastoma protein and histone H1, was used to analyze Cdc25B activity. Also, stable Cdc25B2 and Cdc25B3 overexpression HeLa cell lines were constructed using the tetracycline-regulated expression system and were applied as a tool for screening for inhibitors of Cdc25B. RESULTS: The present study developed and optimized a nonradioisotopic assay method to properly measure Cdc25B activity. Furthermore, we constructed stable Cdc25B2 and Cdc25B3 overexpression HeLa cell lines for the establishment of a strong assay system with which to evaluate the specificity of Cdc25B inhibitors under conditions similar to the intracellular environment. These methods were confirmed as useful tools for measuring Cdc25B activity. CONCLUSION: The nonradioisotopic Cdk1 kinase assay and Cdc25B overexpression cell lines developed in this study can be conveniently used as tools for screening inhibitors of Cdc25B phosphatase as anticancer drugs.

Neoplasia endocrina múltiple tipo 1 con mutación negativa y fenocopias / Multiple endocrine neoplasia type 1 with negative mutation and phenocopies

Introducción: existen 4 tipos de neoplasias endocrinas múltiples, las cuales se caracterizan por la aparición de tumores en 2 o más glándulas endocrinas. La prevalencia de neoplasia endocrina múltiple 1 es aproximadamente 2 por 100 000, y constituyen una enfermedad poco frecuente. Objetivo: descartar, ante la sospecha de una neoplasia endocrina múltiple 1 con mutación negativa, otras enfermedades para poder diagnosticarla como tal. Presentación del caso clínico: mujer de 36 años, con diagnóstico de macroprolactinoma e hiperparatiroidismo primario normocalcémico (neoplasia endocrina múltiple 1 clínica), hallazgos clínicos que justificaron el estudio genético. Inicialmente para neoplasia endocrina múltiple 1, resultó negativo. En pacientes con neoplasia endocrina múltiple 1 clínica -o alta sospecha de neoplasia endocrina múltiple 1 en los que no se identifica mutación- hay que considerar que se trate de una fenocopia y ampliar el estudio genético: CDC73, CDKN1B, CaSR y AIP. También se analizaron estos genes, y fueron negativos. Otra entidad a considerar sería el hiperparatiroidismo aislado familiar. Conclusiones: llegar al diagnóstico de neoplasia endocrina múltiple 1 a veces no es tan simple, como identificar una mutación positiva. Es importante descartar fenocopias, para poder diagnosticar correctamente al paciente, pues esto determinará el seguimiento en búsqueda de otros posibles tumores, lo que -en último término- puede condicionar el pronóstico(AU)

Introduction: there are four types of multiple endocrine neoplasias which are characterized by occurrence of tumors in two or more endocrine glands. The prevalence rate of multiple endocrine neoplasia type 1 is 2 per 100 000 patients approximately and it is a rare disease. Objective: to rule out the existence of any other disease in order to properly diagnose a suspected multiple endocrine neoplasia type 1 with negative mutation. Clinical case presentation: a 36 years-old woman diagnosed with macroprolactinoma and primary normocalcemic hyperparathyroidism (clinical multiple endocrine neoplasia type 1) and clinical findings supporting the performance of a genetic study. The study initially yielded negative results for the above-mentioned disease. However, in those patients with clinical multiple endocrine neoplasia type 1- or high suspicious of multiple endocrine neoplasia type 1 with no identified mutation- it must be considered that there is a phenocopy and the genetic study must be extended to include CDC 73, CDKN1B, CaSR and AIP. These genes were also analyzed with negative results. Another disease to be considered would be isolated family hyperparathyroidism. Conclusions: making the diagnosis of a multiple endocrine neoplasia type 1 is not sometimes as simple as identifying a positive mutation. It is important to rule out possible phenocopies to be able to adequately diagnose a patient, since this will determine the search for other probable tumors which may ultimately influence this prognosis(AU)

Sorbus rufopilosa Extract Exhibits Antioxidant and Anticancer Activities by Inducing Cell Cycle Arrest and Apoptosis in Human Colon Adenocarcinoma HT29 Cells

BACKGROUND: Sorbus rufopilosa, a tsema rowan, is a species of the small ornamental trees in the genus Sorbus and the family Rosaceae found in East Asia. The bioactivities of S. rufopilosa have not yet been fully determined. The objective of this study is to evaluate the antioxidant and anticancer effects of ethanol extract of S. rufopilosa (EESR) and to determine the molecular mechanism of its anticancer activity in human colon carcinoma HT29 cells. METHODS: To examine the antioxidant activity of EESR, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity assay was performed. Inhibitory effect of EESR on cancer cell growth and proliferation was determined by water-soluble tetrazolium salt assay. To investigate the mechanism of EESR-mediated cytotoxicity, HT29 cells were treated with various concentrations of EESR and the induction of cell cycle arrest and apoptosis was analyzed by flow cytometry, 4,6-diamidino-2-phenylindole staining, and Western blot analysis. RESULTS: EESR showed significant antioxidant activity and inhibitory effect on HT29 cell growth in a dose-dependent manner. EESR induced cell cycle arrest at G2/M phase in a dose-dependent manner by modulating cyclin B, cyclin-dependent kinase 1 (CDK1), and CDK inhibitor p21 expression. EESR-induced apoptosis was associated with the upregulation of p53, a death receptor Fas, and a pro-apoptotic protein Bax and the activation of caspase 3, 8, and 9, resulting in the degradation of PARP. CONCLUSIONS: EESR possessing antioxidant activity efficiently inhibits proliferation of HT29 cells by inducing both cell cycle arrest and apoptosis. EESR may be a possible candidate for the anticancer drug development.

Circadian rhythm variation of the clock genes Per1 and cell cycle related genes in different stages of carcinogenesis of buccal mucosa in animal model / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the expression and circadian rhythm variation of biological clock gene Per1 and cell cycle genes p53, CyclinD1, cyclin-dependent kinases (CDK1), CyclinB1 in different stages of carcinogenesis in buccal mucosa and its relationship with the development of buccal mucosa carcinoma.</p><p><b>METHODS</b>Ninety golden hamsters were housed under 12 hours light-12 hours dark cycles, and the model of buccal squamous cell carcinoma was established by using the dimethylbenzanthracene (DMBA) to smear the golden hamster buccal mucosa. Before the DMBA was used and after DMBA was used 6 weeks and 14 weeks respectively, the golden hamsters were sacrificed at 6 different time points (5 rats per time point) within 24 hour, including 4, 8, 12, 16, 20 and 24 hour after lights onset (HALO), and the normal buccal mucosa, precancerous lesions and cancer tissue were obtained, respectively. HE stained sections were prepared to observe the canceration of each tissue. Real time RT-PCR was used to detect the mRNA expression of Per1, p53, CyclinD1, CDK1 and CyclinB1, and a cosine analysis method was applied to determine the circadian rhythm variation of Per1, p53, CyclinD1, CDK1 and CyclinB1 mRNA expression, which were characterized by median, amplitude and acrophase.</p><p><b>RESULTS</b>The expression of Per1, p53, CDK1 and CyclinD1 mRNA in 6 different time points within 24 hours in the tissues of three different stages of carcinogenesis had circadian rhythm, respectively. However, the CyclinB1 mRNA was expressed with circadian rhythm just in normal and cancer tissue (P < 0.05), while in precancerous lesions the circadian rhythm was in disorder (P > 0.05). As the development of carcinoma, the median of Per1 and p53 mRNA expression were significantly decreased (P < 0.05), yet the median of CDK1, CyclinB1 and CyclinD1 mRNA expression were significantly increased (P < 0.05). The amplitude of Per1, p53 and CyclinD1 mRNA expression was significantly decreased as the development of carcinoma (P < 0.05), however the amplitude of CDK1 mRNA expression was significantly increased (P < 0.05). In addition, there was no significant difference in the amplitude of CyclinB1 mRNA expression. The time that the peak expression value of Per1 and CDK1 mRNA appeared (Acrophase) in precancerous lesions was remarkably earlier than that in normal tissues, but the acrophase of p53 and CyclinD1 mRNA expression was remarkably delayed. Moreover, the acrophase of CDK1 and CyclinB1 mRNA expression in cancer tissues was obviously earlier than that in normal tissues, yet there was no significant variation in acrophase of Per1, p53, CyclinD1 mRNA expression between normal tissues and cancer tissues.</p><p><b>CONCLUSIONS</b>The circadian rhythm of clock gene Per1 and cell cycle genes p53, CyclinD1, CDK1, CyclinB1 expression remarkably varied with the occurrence and development of carcinoma. Further research into the interaction between circadian and cell cycle of two cycle activity and relationship with the carcinogenesis may providenew ideas and methods of individual treatment and the mechanism of carcinogenesis.</p>

Effects of β-catenin on differentially expressed genes in multiple myeloma / 华中科技大学学报（医学）（英德文版）

This study aimed to identify the differentially expressed genes after silencing of β-catenin in multiple myeloma transduced with β-catenin shRNA. The DNA microarray dataset GSE17385 was downloaded from Gene Expression Omnibus, including 3 samples of MM1.S (human multiple myeloma cell lines) cells transduced with control shRNA and 3 samples of MM1.S cells transduced with β-catenin shRNA. Then the differentially expressed genes (DEGs) were screened by using Limma. Their underlying functions were analyzed by employing Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. Moreover, DEGs annotation was conducted based on the databases of tumor associated genes, tumor suppressed genes and the transcriptional regulation from patterns to profiles. Furthermore, the protein-protein interaction (PPI) relationship was obtained from STRING and the protein-protein interaction network and the functional modules were visualized by Cytoscape. Then, the pathway enrichment for the DEGs in the functional module was performed. A total of 301 DEGs, including 124 up-regulated and 117 down-regulated DEGs, were screened. Functional enrichment showed that CCNB1 and CDK1 were significantly related to the function of cell proliferation. FOS and JUN were related to innate immune response-activating signal transduction. Pathway enrichment analysis indicated that CCNB1 and CDK1 were most significantly enriched in the pathway of cell cycle. Besides, FOS and JUN were significantly enriched in the Toll-like receptor signaling pathway. FOXM1 was identified as a transcription factor. Moreover, there existed interactions among CCNB1, FOXM1 and CDK1 in PPI network. The expression of FOS, JUN, CCNB1, FOXM1 and CDK1 may be affected by β-catenin in multiple myeloma.

WEE1, histone and tumor / 中南大学学报(医学版)

WEE1 is an important factor for histone transcription, chromosome condensation and regulation of cell cycle progression. WEE1 kinase can phosphorylate Cdc2 and down-regulate Cdc2 kinase activity. It can regulate G2 to M phase transition and cell mitosis. It plays a key role in chromosome condensation delay and histone synthesis, suggesting the important functions of WEE1 in the occurrence and development in cancer. At present, a multiple WEE1 inhibitors have been discovered. A great progress has been made in combination of WEE1 inhibitors with DNA damage treatment (chemotherapy or radiotherapy), which makes WEE1 an important target in cancer treatment.

Anti-cancer Activity of Osmanthus matsumuranus Extract by Inducing G2/M Arrest and Apoptosis in Human Hepatocellular Carcinoma Hep G2 Cells

BACKGROUND: Osmanthus matsumuranus, a species of Oleaceae, is found in East Asia and Southeast Asia. The bioactivities of O. matsumuranus have not yet been fully understood. Here, we studied on the molecular mechanisms underlying anti-cancer effect of ethanol extract of O. matsumuranus (EEOM). METHODS: Inhibitory effect of EEOM on cell growth and proliferation was determined by WST assay in various cancer cells. To investigate the mechanisms of EEOM-mediated cytotoxicity, HepG2 cells were treated with various concentration of EEOM and analyzed the cell cycle arrest and apoptosis induction by flow cytometry, Western blot analysis, 4,6-diamidino-2-phenylindole (DAPI) staining and DNA fragmentation. RESULTS: EEOM showed the cytotoxic activities in a dose-dependent manner in various cancer cell lines but not in normal cells, and HepG2 cells were most susceptible to EEOM-induced cytotoxicity. EEOM induced G2/M arrest in HepG2 cells associated with decreased expression of cyclin-dependent kinase 1 (CDK1), cyclin A and cylcin B, and increased expression of phospho-checkpoint kinase 2, p53 and CDK inhibitor p21. Immunofluorescence staining showed that EEOM-treated HepG2 increased doublet nuclei and condensed actin, resulting in cell rounding. Furthermore, EEOM-mediated apoptosis was determined by Annexin V staining, chromatin condensation and DNA fragmentation. EEOM caused upregulation of FAS and Bax, activation of caspase-3, -8, -9, and fragmentation of poly ADP ribose polymerase. CONCLUSIONS: These results suggest that EEOM efficiently inhibits proliferation of HepG2 cells by inducing both G2/M arrest and apoptosis via intrinsic and extrinsic pathways, and EEOM may be used as a cancer chemopreventive agent in the food or nutraceutical industry.

Effects of suppressed autophagy on mitochondrial dynamics and cell cycle of N2a cells / 华中科技大学学报（医学）（英德文版）

Autophagy dysregulation, mitochondrial dynamic abnormality and cell cycle re-entry are implicated in the vulnerable neurons of patients with Alzheimer's disease. This study was designed to testify the association among autophagy, mitochondrial dynamics and cell cycle in dividing neuroblastoma (N2a) cells. The N2a cells were cultured in vitro and treated with different concentrations of 3-methyladenine (3-MA). The cell viability was detected by methyl thiazolyl tetrazolium (MTT) assay. They were randomly divided into control group (cells cultured in normal culture medium) and 3-MA group (cells treated with 10 mmol/L 3-MA). The cell cycle was analyzed in the two groups 3, 6, 12, and 24 h after treatment by flow cytometry. Western blotting was used to evaluate the expression levels of mitofission 1 (Fis1), mitofusin 2 (Mfn2), microtubule-associated protein 1 light chain 3 (LC3), cell cycle-dependent kinase 4 (CDK4) and cdc2. The flow cytometry revealed that the proportion of cells in G(2)/M was significantly increased, and that in G0/G1 was significantly reduced in the 3-MA group as compared with the control group. Western blotting showed that the expression levels of Fis1, LC3, and CDK4 were significantly up-regulated in the 3-MA group at the four indicated time points as compared with the control group. Mfn2 was initially decreased in the 3-MA group, and then significantly increased at 6 h or 12 h. Cdc2 was significantly increased in the 3-MA group at 3 h and 6 h, and then dropped significantly at 12 h and 24 h. Our data indicated that 3-MA-induced suppressed autophagy may interfere with the cell cycle progression and mitochondrial dynamics, and cause cell death. There are interactions among cell cycle, mitochondrial dynamics and autophagy in neurons.

Fucoidan induces apoptosis of HepG2 cells by down-regulating p-Stat3 / 华中科技大学学报（医学）（英德文版）

Fucoidan is one of the main bioactive components of polysaccharides. The current study was focused on the anti-tumor effects of fucoidan on human heptoma cell line HepG2 and the possible mechanisms. Fucoidan treatment resulted in cell cycle arrest and apoptosis of HepG2 cells in a dose-dependent manner detected by MTT assay, flow cytometry and fluorescent microscopy. The results of flow cytometric analysis revealed that fucoidan induced G2/M arrest in the cell cycle progression. Hoechst 33258 and Annexin V/PI staining results showed that the apoptotic cell number was increased, which was associated with a dose-dependent up-regulation of Bax and down-regulation of Bcl-2 and p-Stat3. In parallel, the up-regulation of p53 and the increase in reactive oxygen species were also observed, which may play important roles in the inhibition of HepG2 growth by fucoidan. In the meantime, Cyclin B1 and CDK1 were down-regulated by fucoidan treatment. Down-regulation of p-Stat3 by fucoidan resulted in apoptosis and an increase in ROS in response to fucoidan exposure. We therefore concluded that fucoidan induces apoptosis through the down-regulation of p-Stat3. These results suggest that fucoidan may be used as a novel anti-cancer agent for hepatocarcinoma.

Inhibitions of SphK1 inhibitor SKI II on cell cycle progression and cell invasion of hepatoma HepG2 cells / 药学学报

Sphingosine kinase 1 (SphK1) plays critical roles in cell biological functions. Here we investigated the effects of SphK1 inhibitor SKI II on hepatoma HepG2 cell cycle progression and invasion. Cell survival was determined by SRB assay, cell cycle progression was assayed by flow cytometry, the ability of cell invasion was measured by Matrigel-Transwell assay and protein expression was detected by Western blotting. The results showed that SKI II markedly inhibited HepG2 cell survival in a dose-dependent manner, induced G1 phase arrest in HepG2 cell and inhibited cell invasion. SKI II markedly decreased the expressions of G1-phase-related proteins CDK2, CDK4 and Cdc2 and the levels of cell invasion-associated proteins MMP2 and MMP9. The results showed that SKI II inhibited cell cycle progression and cell invasion, implying SphK1 as a potential target for hepatoma treatment.

Regulation mechanism of eIF3 P170 on developing myocardial cell cycle / 中南大学学报(医学版)

OBJECTIVE@#To investigate the expression of eIF3P170, cdc2, cyclinB1 and cyclinD1 in developing cardiac myocytes, and the correlation between eIF3P170 with cdc2, cyclin D1, and cyclin B1 in mice.@*METHODS@#Mouse cardiac myocytes were obtained at different time points. RT-PCR was employed to detect the expression of eIF3P170, cdc2, cyclin D1 and cyclin B1 mRNA.@*RESULTS@#Expressions of eIF3P170, cdc2, cyclinD1 and cyclinB1 mRNA were higher in the embryonic Day 13, 15, 18 and postnatal Day 1, 2, 3, 5. Expressions at postnatal Day 5 reached the highest (all P values<0.05 vs other time points), and then the expressions of these genes gradually decreased to the weakest at postnatal Day 30 (all P values<0.05 vs other time points). The mRNA expression of eIF3P170 was positively correlated with cdc2, cyclin D1 and cyclin B1 mRNA expression respectively.@*CONCLUSION@#The mRNA expressions of eIF3 P170, cdc2, cyclin D1 and cyclin B1 in the embryo and the early life after birth are high. They reach the maximum at postnatal Day 5, then gradually decreased.

Inhibitory Effect of Melanoma Differentiation Associated Gene-7/Interleukin-24 on Invasion In Vitro of Human Melanoma Cancer Cells

The acquisition of metastasis potential is a critical point for malignant tumors. Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) is a potential tumor suppress gene and frequently down-regulated in malignant tumors. It has been implicated that overexpression of MDA-7 led to proliferation inhibition in many types of human tumor. Invasion is an important process which is potential to promote tumor metastasis. However, the role and potential molecular mechanism of mda-7/IL-24 to inhibit the invasion of human melanoma cancer is not fully clear. In this report, we identified a solid role for mda-7/IL-24 in invasion inhibition of human melanoma cancer LiBr cells, including decreasing of adhesion and invasion in vitro, blocking cell cycle, down-regulating the expression of ICAM-1, MMP-2/9, CDK1, the phosphorylation of ERK and Akt, NF-kappaB and AP-1 transcription activity. Meanwhile, there was an increased expression of PTEN in mda-7/IL-24 over-expression LiBr cells. Our results demonstrated that mda-7/IL-24 is a potential invasion suppress gene, which inhibits the invasion of LiBr cells by the down-regulation of ICAM-1, MMP-2/9, PTEN, and CDK1 expression. The molecular pathways involved were the MAPK/ERK, PI3K-Akt, NF-kappaB, and AP-1. These findings suggest that mda-7/IL-24 may be used as a possible therapeutic strategy for human melanoma cancer.

BCL2 antagonist of cell death kinases, phosphatases, and ovarian cancer sensitivity to cisplatin / 부인종양

OBJECTIVE: The BCL2 family proteins are critical mediators of cellular apoptosis and, as such, have been implicated as determinants of cancer cell chemo-sensitivity. Recently, it has been demonstrated that the phosphorylation status of the BCL2 antagonist of cell death (BAD) protein may influence ovarian cancer (OVCA) cell sensitivity to cisplatin. Here, we sought to evaluate how kinase and phosphatase components of the BAD apoptosis pathway influence OVCA chemo-sensitivity. METHODS: Protein levels of cyclin-dependent kinase 1 (CDK1) and protein phosphatase 2C (PP2C) were measured by immunofluorescence in a series of 64 primary advanced-stage serous OVCA patient samples. In parallel, levels of cAMP-dependent protein kinase (PKA), AKT, and PP2C were quantified by Western blot analysis in paired mother/daughter platinum-sensitive/resistant OVCA cell lines (A2008/C13, A2780S/A2780CP, Chi/ChiR). BAD pathway kinase CDK1 was depleted using siRNA transfection, and the influence on BAD phosphorylation and cisplatin-induced apoptosis was evaluated. RESULTS: OVCA patient samples that demonstrated complete responses to primary platinum-based therapy demonstrated 4-fold higher CDK1 (p<0.0001) and 2-fold lower PP2C (p=0.14) protein levels than samples that demonstrated incomplete responses. Protein levels of PP2C were lower in the platinum-resistant versus that shown in the platinum-sensitive OVCA cell line sub-clones. Levels of PKA were higher in all platinum-resistant than in platinum-sensitive OVCA cell line sub-clones. Selective siRNA depletion of CDK1 increased sensitivity to cisplatin-induced apoptosis (p<0.002). CONCLUSION: BAD pathway kinases and phosphatases, including CDK1 and PP2C, are associated with OVCA sensitivity to platinum and may represent therapeutic opportunities to enhance cytotoxic efficacy.

Essential role of TRPC6 in the proliferation of gastric cancer and its mechanism / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the essential role and mechanism of TRPC6 gene in the development of gastric cancer.</p><p><b>METHODS</b>The expression of TRPC6 protein was assessed in gastric cancer tissues and normal tissues adjacent to the cancer from 30 patients with gastric cancer. The inhibiting effect of TRPC6 activity on cell growth, cell cycle of a human gastric cancer cell line AGS cells, tumor progression and development of xenografted human gastric cancer in a mouse model was tested using dominant-negative mutant TRPC6 (DNC6). The survival of mice bearing xenografted tumors in the GFP and DNC6 was compared using Kaplan-Meier analysis. All statistical tests were two-sided.</p><p><b>RESULTS</b>The TRPC6 protein in the tumor tissues and para-tumor tissues was (21.60 ± 8.32)% versus (7.14 ± 2.24)%. After transfection of DNC6 virus for 24 hours, 48 hours, 72 hours and 96 hours, the growth inhibition rates of gastric cancer cells were (36.90 ± 1.13)%, (44.06 ± 2.17)%, (52.12 ± 2.76)% and (50.89 ± 1.97)%, respectively. The clone formation rates of control group and DNC6 group were (14.70 ± 3.00)% versus (43.80 ± 7.00)%. After transfection with DNC6 virus for 0, 24, 36 and 48 hours, the G(2)/M phase arrest was (20.34 ± 1.98)%, (24.31 ± 2.37)%, (27.70 ± 2.36)%, (35.10 ± 3.0)% in the DNC6 group and (18.40 ± 2.01)%, (18.0% ± 1.72)%, (17.50 ± 1.74)%, (16.80 ± 1.71)% in the control group, respectively. Inhibition of TRPC6 activity also reduced the subcutaneous tumor volume in the mouse models with xenografted human tumors (P < 0.05).</p><p><b>CONCLUSION</b>In the preclinical models tested, TRPC6 channels are essential for gastric cancer development via regulation of G(2)/M phase transition.</p>

Crystal structure of human Gadd45γ corrected reveals an active dimer

The human Gadd45 protein family plays critical roles in DNA repair, negative growth control, genomic stability, cell cycle checkpoints and apoptosis. Here we report the crystal structure of human Gadd45γ [corrected], revealing a unique dimer formed via a bundle of four parallel helices, involving the most conserved residues among the Gadd45 isoforms. Mutational analysis of human Gadd45γ [corrected] identified a conserved, highly acidic patch in the central region of the dimer for interaction with the proliferating cell nuclear antigen (PCNA), p21 and cdc2, suggesting that the parallel dimer is the active form for the interaction. Cellular assays indicate that: (1) dimerization of Gadd45γ [corrected] is necessary for apoptosis as well as growth inhibition, and that cell growth inhibition is caused by both cell cycle arrest and apoptosis; (2) a conserved and highly acidic patch on the dimer surface, including the important residues Glu87 and Asp89, is a putative interface for binding proteins related to the cell cycle, DNA repair and apoptosis. These results reveal the mechanism of self-association by Gadd45 proteins and the importance of this self-association for their biological function.

Hypoxia induces Wee1 expression and attenuates hydrogen peroxide-induced endothelial damage in MS1 cells

In an oxygen-depleted environment, endothelial cells initiate an adaptive pattern of synthesis, which may enable them to survive hypoxic crises. Using high-resolution two-dimensional gel electrophoresis in conjunction with mass spectroscopy, we obtained a 24 differential display of proteins in the pancreatic endothelial cell line, MS-1, at four time points following induction of hypoxia. The induction of Wee1 under hypoxia was confirmed both at the mRNA and protein levels. The phosphorylation of cell division cycle 2, which is downstream of Wee1, was also increased after hypoxic exposure. In addition, pre-exposure to hypoxia attenuated a decrease in hydrogen peroxide-induced cell number. The induction of bax (a pro-apoptotic protein) and reduction of bcl (an anti-apoptotic protein) after hypoxia stimulus were also attenuated by hypoxic pre-exposure. Moreover, hydrogen peroxide-induced morphologic damage did not appear in the wild-type Wee1-expressing cells. Taken together, our results suggest that Wee1 may have important role in hypoxia-induced pathophysiological situations in endothelial cells.

Semi-empirical calculations on paullones, a promising class of cyclin-dependent kinase inhibitors.

Paullones, a group of ATP-competitive 7,12-dihydroindolo [3,2-d][1]benzazepin-6(5H)-ones are well-established cyclin-dependent kinase (CDK) inhibitors with promising anti-tumoral properties. In this study, AM1 (Austin model 1) calculations have been performed on paullones and their biological activities have been explained with respect to their HOMO and LUMO energies. 9-Substituted paullones with electrophilic character show high potencies. The interaction of 9th substitutent with Phe-80 of receptor plays a key role in binding and potency. The study will help medicinal chemists to design efficient CDK inhibitiors.