Study on the mechanism of miRNA expression profile and enrichment analysis on p21 in oxygen-induced retinopathy mice / 中华眼底病杂志

Objective:To observe the expression of miRNA in retinal tissue of mice with oxygen-induced retinopathy (OIR), and screen miRNAs related to p21 and retinal neovascularization (RNV) formation.Methods:A experimental study. Forty healthy 7-day-old C57BL/6J mice were randomly divided into normal group and OIR group, with 20 mice in each group. The oxygen induced RNV model was constructed in the OIR group, and no treatment was performed in the normal group. At the age of 17 days, the mice were killed and the RNV of mice was observed by retinal fluorescence; the nuclei of vascular endothelium that broke through the inner limiting membrane of retina were counted under light microscope. The retinal tissues were taken for miRNA chip analysis to detect the differentially expressed miRNAs between the normal group and the OIR group. The resulting differential miRNA target genes were subjected to enrichment analysis based on gene annotation (GO) and Kyoto Encyclopedia of genes and genomes (KEGG); miRNAs and pathways that may be related to p21 were screened through Targetscan, MiRanda and MicroT-CDs database alignment. Independent sample t-test was used for pairwise comparison between groups. Results:Compared with the normal group, the area of nonperfusion area, RNV and the number of vascular endothelial nuclei that broke through the inner limiting membrane of the retina in the OIR group increased significantly, differences were statistically significant ( t=18.800, 9.025; P<0.05). Compared with the normal group, there were 54 miRNAs that were statistically differentially expressed in the OIR group, of which 47 were up-regulated and 7 were down-regulated. A total of 13 miRNAs related to p21 were screened from the alignment results of the three databases with the obtained differential miRNAs. According to the difference multiples, they were miR-7218-5p, miR-322-5p, miR-224-5p, miR-335-5p, miR-329-3p, miR-362-3p, miR-532-5p, miR-20b-5p, miR-20a-5p, miR-195a-5p, miR-423-5p, miR-497a-5p, and miR-129-5p. Differential miRNA target gene enrichment analysis yielded 1 112 go entries and 50 KEGG pathways, of which 50 go entries and 13 KEGG pathways were related to p21. Conclusion:13 miRNAs related to p21 were screened out in the OIR model.

Study on the mechanism of miRNA expression profile and enrichment analysis on p21 in oxygen-induced retinopathy mice / 中华眼底病杂志

Objective:To observe the expression of miRNA in retinal tissue of mice with oxygen-induced retinopathy (OIR), and screen miRNAs related to p21 and retinal neovascularization (RNV) formation.Methods:A experimental study. Forty healthy 7-day-old C57BL/6J mice were randomly divided into normal group and OIR group, with 20 mice in each group. The oxygen induced RNV model was constructed in the OIR group, and no treatment was performed in the normal group. At the age of 17 days, the mice were killed and the RNV of mice was observed by retinal fluorescence; the nuclei of vascular endothelium that broke through the inner limiting membrane of retina were counted under light microscope. The retinal tissues were taken for miRNA chip analysis to detect the differentially expressed miRNAs between the normal group and the OIR group. The resulting differential miRNA target genes were subjected to enrichment analysis based on gene annotation (GO) and Kyoto Encyclopedia of genes and genomes (KEGG); miRNAs and pathways that may be related to p21 were screened through Targetscan, MiRanda and MicroT-CDs database alignment. Independent sample t-test was used for pairwise comparison between groups. Results:Compared with the normal group, the area of nonperfusion area, RNV and the number of vascular endothelial nuclei that broke through the inner limiting membrane of the retina in the OIR group increased significantly, differences were statistically significant ( t=18.800, 9.025; P<0.05). Compared with the normal group, there were 54 miRNAs that were statistically differentially expressed in the OIR group, of which 47 were up-regulated and 7 were down-regulated. A total of 13 miRNAs related to p21 were screened from the alignment results of the three databases with the obtained differential miRNAs. According to the difference multiples, they were miR-7218-5p, miR-322-5p, miR-224-5p, miR-335-5p, miR-329-3p, miR-362-3p, miR-532-5p, miR-20b-5p, miR-20a-5p, miR-195a-5p, miR-423-5p, miR-497a-5p, and miR-129-5p. Differential miRNA target gene enrichment analysis yielded 1 112 go entries and 50 KEGG pathways, of which 50 go entries and 13 KEGG pathways were related to p21. Conclusion:13 miRNAs related to p21 were screened out in the OIR model.

Comparison of senescence progression in mesenchymal cells from human umbilical cord walls measured by immunofluorescence and flow cytometry of p16 and p21 / Comparação da progressão da senescência em células mesenquimais de parede de cordão umbilical humano medida por imunofluorescência e citometria de fluxo de p16 e p21

ABSTRACT Objective To follow the expansion of mesenchymal stem cells from umbilical cords by two classic senescence markers, p16 (INK4A) and p21 (CDKN1A), using practical, fast, and less expensive methods than the gold standard Western blotting technique, to evaluate its applicability in the laboratory. Methods Mesenchymal stem cells from umbilical cords were isolated from Wharton's jelly and, after quality control, morphological and immunophenotypic characterization by flow cytometry, were expanded in culture until coming close to cell cycle arrest (replicative senescence). Results A comparison was made between young cells, at passage 5, and pre-senescent cells, at passage 10, evaluating the protein expression of the classic cell senescence markers p16 and p21, comparing the results obtained by Western blotting with those obtained by flow cytometry and indirect immunofluorescence. Conclusion Follow-up of cell cultures, through indirect p16 immunofluorescence, allows the identification of mesenchymal stem cells from umbilical cord cultures at risk of reaching replicative senescence.

RESUMO Objetivo Acompanhar a expansão de células-tronco mesenquimais de cordão umbilical por dois marcadores clássicos de senescência, p16 (INK4A) e p21 (CDKN1A), usando métodos práticos, rápidos e com custo menor do que a técnica padrão-ouro de Western blotting, para avaliar sua aplicabilidade em laboratório. Métodos Células-tronco mesenquimais de cordão umbilical foram isoladas da geleia de Wharton e, após controle de qualidade e caracterização morfológica e imunofenotípica por citometria de fluxo, foram expandidas em cultura, até chegarem próximas à parada do ciclo celular (senescência replicativa). Resultados Foi feita a comparação entre células jovens, na passagem 5, e células pré-senescentes, na passagem 10, avaliando a expressão proteica dos marcadores clássicos de senescência celular p16 e p21, comparando os resultados obtidos por Western blotting com os obtidos por citometria de fluxo e imunofluorescência indireta. Conclusão O seguimento de culturas celulares, por meio da imunofluorescência indireta de p16, permite identificar as culturas de células-tronco mesenquimais de cordão umbilical em risco de atingirem a senescência replicativa.

The role of p21/CIP1/WAF1 (p21) in the negative regulation of the growth hormone/growth hormone receptor and epidermal growth factor/epidermal growth factor receptor pathways, in growth hormone transduction defect

PURPOSE: Growth hormone transduction defect (GHTD) is characterized by severe short stature, impaired STAT3 (signal transducer and activator of transcription-3) phosphorylation and overexpression of the cytokine inducible SH2 containing protein (CIS) and p21/CIP1/WAF1. To investigate the role of p21/CIP1/WAF1 in the negative regulation of the growth hormone (GH)/GH receptor and Epidermal Growth Factor (EGF)/EGF Receptor pathways in GHTD. METHODS: Fibroblast cultures were developed from gingival biopsies of 1 GHTD patient and 1 control. The protein expression and the cellular localization of p21/CIP1/WAF1 was studied by Western immunoblotting and immunofluorescence, respectively: at the basal state and after induction with 200-μg/L human GH (hGH) (GH200), either with or without siRNA CIS (siCIS); at the basal state and after inductions with 200-μg/L hGH (GH200), 1,000-μg/L hGH (GH1000) or 50-ng/mL EGF. RESULTS: After GH200/siCIS, the protein expression and nuclear localization of p21 were reduced in the patient. After successful induction of GH signaling (control, GH200; patient, GH1000), the protein expression and nuclear localization of p21 were reduced. After induction with EGF, p21 translocated to the cytoplasm in the control, whereas in the GHTD patient it remained located in the nucleus. CONCLUSIONS: In the GHTD fibroblasts, when CIS is reduced, either after siCIS or after a higher dose of hGH (GH1000), p21’s antiproliferative effect (nuclear localization) is also reduced and GH signaling is activated. There also appears to be a positive relationship between the 2 inhibitors of GH signaling, CIS and p21. Finally, in GHTD, p21 seems to participate in the regulation of both the GH and EGF/EGFR pathways, depending upon its cellular location.

Suppressing effect of p21WAF1/CIP1 on traumatic proliferative vitreoretinopathy in rabbits / 中华实验眼科杂志

Background p21 is a cyclin-dependent kinase inhibitor,and it can prevent cells from going through the G1/S phase checkpoint and inhibit cell proliferation.Stuies determined that the expression level of p21 WAF1/CIP1 is associated with proliferative diseases.Traumatic proliferative vitreoretinopathy (PVR) is a proliferative response of eye.Understaining the relationship of dynamic expression levels of p21 WAF1/CIP1 in PVR is of significance for the prevention and management of PVR.Objective This study was to investigate the expression of p21 WAF1/CIP1 during the course of experimental traumatic PVR in rabbits.Methods Fifty-four pigmented rabbits were randomized into the normal control group and different experimerital groups,and one lateral eye of each rabbit served as experimental eye.PVR models were established by intravitreal injection of human platelet-rich plasma (PRP) (0.4 ml)combined with cryotherapy for 5 seconds,and vitreous and retinas were examined with B type sonography.The rabbits were sacrificed in 7,14,21 and 28 days after operation,and histopathological examination of the retinas was performed by haematoxylin and eosin stain.The expression levels of p21WAF1/CIP1 protein and gene were detected by immunohistochemistry,Western blot and reverse transcription-PCR (RT-PCR).The use and care of the rabbits complied with Statement of ARVO.Results B type sonography showed that the retinal morphology was normal in the normal control group.However,the proliferative membrane was gradually thickened 1 to 7 days after operation.Retinal folds of rabbits were seen in 7 days,and tractional retinal detachment was found in 14 days and 28 days after operation.The histopathological examination of the retinas showed epiretinal membrane and infiltration of inflammatory cells 7 days and fixed ruffle 28 days after operation.The p21WAF1/CIP1 was strongly expressed in the cell nucleus of retinal ganglion cell layer (GCL) and inner nuclear layer (INL) in the normal control group,and the expression was gradually weakened after modeling,with the weakest expression in the retinas in 14 days after modeling.The relative expression levels of p21 WAF1/CIP1 protein was 0.74±0.08,0.60±0.05,0.56±0.03,0.74±0.02 and 0.65 ±0.04 in the normal control group,postoperative 7-day group,postoperative 14-day group,postoperative 21-day group and postoperative 28-day group,respectively,showing a significant difference among the groups (F =20.55,P =0.00),and the expression levels of p21WAF1/CIP1 protein were significantly lower in the postoperative 7-day group and postoperative 14-day group than those of the normal control group,postoperative 21-day group and postoperative 28-day group (all at P＜0.05).The relative expression levels of p21 WAF1/CIP1 mRNA was 0.65 ± 0.09,0.57 ± 0.05,0.45 ±0.04,0.46±0.02 and 0.47±0.04 in the normal control group,postoperative 7-day group,postoperative 14-day group,postoperative 21-day group and postoperative 28-day group,respectively,with a significant difference among the groups (F =18.06,P =0.00),and the expression levels were significantly lower in the postoperative 14-day group,postoperative 21-day group and postoperative 28-day group than those of the normal control group and postoperative 7-day group (all at P＜0.05).Conclusions The dynamic expression of p21WAF1/CIP1 in the retinas is consistant with the prograssion of traumatic PVR,and the reduce tendency of p21 WAF1/CIP1expression is similar to cell prolieration change,indicating that reduce of p21WAF1/CIP1 expression in the retinas may promote the development of traumatic PVR.

Role of p21 and p27 in carcinogenesis and drug resistance / 国际外科学杂志

Human cancers arise from an imbalance of cell growth and cell death.Critical factors that control the balance are those regulate the cell cycle.Several molecular effectors have been identified to be able to regulate specific phases of the cell cycle,including cyclins,cyclin-dependent kinases (CDKs) and CDK inhibitors.Notably,deficiency of two G1-checkpoint CDK inhibitors-p21 (CDKN1A) and p27 (CDKN1B)-has been implicated to be correlated with initiation or progression of many human malignancies or cancer cells drug-resistance.However,contradict reports also suggested that p21 and p27 could promote tumor progression.Here,we summarized the historic and recent studies on these two CDK inhibitors,including their identification as well as their roles in carcinogenesis and drug resistance.

Effect of reinforcing spleen and kidney on the p21 and TGF-β1 in renal tissue of adriamycin-induced CKD in rats / 国际中医中药杂志

Objective To investigate the effect of reinforcing spleen and kidney method on adriamycin-induced CKD in rats and to explore its possible mechanism.Methods Totally 36 Sprague-Dawley rats were randomly divided into a Adriamycin-induced model group and a control group.The model group was further divided into five groups:the Adriamycin-induced model control group,bennazepril-treated group,and TCM treated low,moderate,and high dose groups.The level of serum creatinine,urea nitrogen,24hours urine protein and urine creatinine were measured at 14,28,42 days after establishing the model rats.And the protein expression of transforming growth factor-β1 (TGF-β1) and cyclin-dependent kinase inhibitor p21cip1 (p21)were detected by immunohistochemistry.Results The proteinuria was observed on the seventh day after injection of adriamycin in adriamycin nephropathy model group,and reached summit on the fourteenth day.Both TCM treated groups and benazepril group reduced the level of urine protein within 24 hours (P＜0.05),the reduction was most remarkable in the TCM high dose group.The expression of p21 and TGF-β1 (p21 288627.66±97021.65,TGF-β1 98405.14± 19216.89) in kidney increased in the model groups,while the TCM treated high dose group (p21 518886.35±6810.89,TGF-β1 222012.95± 50484.73) was significantly lower than the model control group (P＜ 0.05).Conclusion Reinforcing spleen and kidney method could decrease the level of urine protein within 24 hours by regulating the expression of p21 and TGF-β1,so thus to protect renal function and delay progress of kidney disease.

Methylation of eukaryotic elongation factor 2 induced by basic fibroblast growth factor via mitogen-activated protein kinase

Protein arginine methylation is important for a variety of cellular processes including transcriptional regulation, mRNA splicing, DNA repair, nuclear/cytoplasmic shuttling and various signal transduction pathways. However, the role of arginine methylation in protein biosynthesis and the extracellular signals that control arginine methylation are not fully understood. Basic fibroblast growth factor (bFGF) has been identified as a potent stimulator of myofibroblast dedifferentiation into fibroblasts. We demonstrated that symmetric arginine dimethylation of eukaryotic elongation factor 2 (eEF2) is induced by bFGF without the change in the expression level of eEF2 in mouse embryo fibroblast NIH3T3 cells. The eEF2 methylation is preceded by ras-raf-mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK1/2)-p21(Cip/WAF1) activation, and suppressed by the mitogen-activated protein kinase (MAPK) inhibitor PD98059 and p21(Cip/WAF1) short interfering RNA (siRNA). We determined that protein arginine methyltransferase 7 (PRMT7) is responsible for the methylation, and that PRMT5 acts as a coordinator. Collectively, we demonstrated that eEF2, a key factor involved in protein translational elongation is symmetrically arginine-methylated in a reversible manner, being regulated by bFGF through MAPK signaling pathway.

Methylation of eukaryotic elongation factor 2 induced by basic fibroblast growth factor via mitogen-activated protein kinase

Protein arginine methylation is important for a variety of cellular processes including transcriptional regulation, mRNA splicing, DNA repair, nuclear/cytoplasmic shuttling and various signal transduction pathways. However, the role of arginine methylation in protein biosynthesis and the extracellular signals that control arginine methylation are not fully understood. Basic fibroblast growth factor (bFGF) has been identified as a potent stimulator of myofibroblast dedifferentiation into fibroblasts. We demonstrated that symmetric arginine dimethylation of eukaryotic elongation factor 2 (eEF2) is induced by bFGF without the change in the expression level of eEF2 in mouse embryo fibroblast NIH3T3 cells. The eEF2 methylation is preceded by ras-raf-mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK1/2)-p21(Cip/WAF1) activation, and suppressed by the mitogen-activated protein kinase (MAPK) inhibitor PD98059 and p21(Cip/WAF1) short interfering RNA (siRNA). We determined that protein arginine methyltransferase 7 (PRMT7) is responsible for the methylation, and that PRMT5 acts as a coordinator. Collectively, we demonstrated that eEF2, a key factor involved in protein translational elongation is symmetrically arginine-methylated in a reversible manner, being regulated by bFGF through MAPK signaling pathway.

Chlorpromazine activates p21(Waf1/Cip1) gene transcription via early growth response-1 (Egr-1) in C6 glioma cells

2-Chloro-10-[3(-dimethylamino)propyl]phenothiazinemonohydrochloride (chlorpromazine) is a phenothiazine derivative used clinically to control psychotic disorders. It also exhibits an anticancer activity. Treatment with chlorpromazine (CPZ) results in cell-cycle arrest at the G2/M phase in rat C6 glioma cells. CPZ reduces the expression of cell cycle-related proteins, such as cyclin D1, cyclin A, and cyclin B1, but causes an increase in the p21(Waf1/Cip1) level. The molecular mechanism by which CPZ regulates p21(Waf1/Cip1) expression is unknown. Here, we provide evidence that CPZ activates the p21(Waf1/Cip1) gene promoter via induction of the transcription factor early growth response-1 (Egr-1) independently of p53 in C6 cells. A point mutation in the Egr-1-binding motif within the p21(Waf1/Cip1) promoter abrogated promoter inducibility due to CPZ. Forced expression of Egr-1 enhanced p21(Waf1/Cip1) promoter activity. In contrast, knockdown of endogenous Egr-1 by small interference RNA attenuated CPZ-induced p21(Waf1/Cip1) promoter activity. A chromatin immunoprecipitation assay demonstrated that Egr-1 binds to the p21(Waf1/Cip1) gene promoter. Further analysis showed that the ERK and JNK MAP kinases are required for induction of Egr-1 by CPZ. Finally, stable silencing of Egr-1 expression lead to attenuated CPZ-inducible p21(Waf1/Cip1) expression and inhibited G2/M phase cell-cycle arrest. These results demonstrate that a functional link between ERK and JNK MAP kinase pathways and p21(Waf1/Cip1) induction via Egr-1 contributes to CPZ-induced anticancer activity in C6 glioma cells.

Frequency of polymorphisms and protein expression of cyclin-dependent kinase inhibitor 1A (CDKN1A) in central nervous system tumors / Frequência dos polimorfismos e da expressão protéica do inibidor de quinase dependente de ciclina 1A (CDKN1A) em tumores do sistema nervoso central

Context and objective: Genetic investigation of central nervous system (CNS) tumors provides valuable information about the genes regulating proliferation, differentiation, angiogenesis, migration and apoptosis in the CNS. The aim of our study was to determine the prevalence of genetic polymorphisms (codon 31 and 3' untranslated region, 3'UTR) and protein expression of the cyclin-dependent kinase inhibitor 1A (CDKN1A) gene in patients with and without CNS tumors. Design and setting: Analytical cross-sectional study with a control group, at the Molecular Biology Laboratory, Pediatric Oncology Department, Hospital das Clínicas de Ribeirão Preto. Methods: 41 patients with CNS tumors and a control group of 161 subjects without cancer and paires for sex, age and ethnicity were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Protein analysis was performed on 36 patients with CNS tumors, using the Western Blotting technique. Results: The frequencies of the heterozygote (Ser/Arg) and polymorphic homozygote (Arg/Arg) genotypes of codon 31 in the control subjects were 28.0 percent and 1.2 percent, respectively. However, the 3'UTR site presented frequencies of 24.2 percent (C/T) and 0.6 percent (T/T). These frequencies were not statistically different (P > 0.05) from those seen in the patients with CNS tumors (19.4 percent and 0.0 percent, codon 31; 15.8 percent and 2.6 percent, 3'UTR site). Regarding the protein expression in ependymomas, 66.67 percent did not express the protein CDKN1A. The results for medulloblastomas and astrocytomas were similar: neither of them expressed the protein (57.14 percent and 61.54 percent, respectively). Conclusion: No significant differences in protein expression patterns or polymorphisms of CDKN1A in relation to the three types of CNS tumors were observed among Brazilian subjects.

Contexto e objetivo: A investigação genética dos tumores do sistema nervoso central (SNC) provê valiosa informação sobre os genes que regulam a proliferação, diferenciação, angiogênese, migração e apoptose. O objetivo deste estudo é determinar a prevalência entre os polimorfismos genéticos (códon 31 e da região 3' não traduzida, 3'UTR) e a expressão protéica do gene inibidor de quinase dependente de ciclina 1A (CDKN1A) em pacientes com e sem tumor do SNC. Tipo de estudo e local: Estudo transversal analítico com grupo controle, desenvolvido no Laboratório de Biologia Molecular do Departamento de Oncologia Pediátrica do Hospital das Clínicas de Ribeirão Preto. Métodos: 41 pacientes com tumor do SNC e um grupo controle de 161 indivíduos sem câncer pareados por idade, sexo e etnia foram genotipados mediante uma reação de polimorfismo no comprimento de fragmentos de restrição (RFLP). A análise das proteínas foi realizada em 36 pacientes com tumor de SNC mediante Western Blotting. Resultados: A frequência do genótipo heterozigoto (Ser/Arg) e do homozigoto polimórfico (Arg/Arg) do códon 31 nos controles foi 28,0 por cento e 1,2 por cento, respectivamente. Entretanto, o sítio 3'UTR apresentou uma frequência de 24,2 por cento (C/T) e 0,6 por cento (T/T). Estas frequências não são significativamente diferentes (P > 0,05) daquelas observadas no grupo dos pacientes com tumor de SNC (19,4 por cento e 0,0 por cento, códon 31; 15,8 por cento e 2,6 por cento, sítio 3'UTR). Com respeito à expressão protéica, nos ependimomas, 66,67 por cento não expressaram a proteína CDKN1A. Estes resultados foram similares entre os meduloblastomas e os astrocitomas, os quais não expressaram a proteína com 57,14 por cento e 61,54 por cento, respectivamente. Conclusão: Não foram encontradas diferenças significativas entre o padrão de expressão protéica, polimorfismos de CDKN1A e os três tipos de tumores de SNC em indivíduos brasileiros.

The orphan nuclear receptor SHP inhibits apoptosis during the monocytic differentiation by inducing p21WAF1

Small heterodimer partner (SHP) is an atypical member of nuclear receptor superfamily that lacks a DNA-binding domain. In previous study, we showed that SHP, c-jun, p65 of NF-kappaB subunits, and p21WAF1 expression was increased during monocytic differentiaton with the exposure of human leukemia cells to a differentiation agent, PMA. In this study, c-Jun and p65 were shown to mediate the transcriptional activation of the SHP promoter. In addition, SHP induced the cell cycle regulatory protein levels and cooperatively increased an induction of p21WAF1 expression with p65. Furthermore, SHP protected differentiated cells from etoposide-induced cellular apoptosis through the induction and cytoplasmic sequestration of p21WAF1. Complex formation between SHP and p21WAF1 was demonstrated by means of coimmunoprecipitation. These results suggest that SHP prolongs a cellular survival of differentiating monocytes through the transcriptional regulation of target genes of cell survival and differentiation.

JNK inhibitor SP600125 promotes the formation of polymerized tubulin, leading to G2/M phase arrest, endoreduplication, and delayed apoptosis

The JNK inhibitor SP600125 strongly inhibits cell proliferation in many human cancer cells by blocking cell-cycle progression and inducing apoptosis. Despite extensive study, the mechanism by which SP600125 inhibits mitosis-related effects in human leukemia cells remains unclear. We investigated the effects of SP600125 on the inhibition of cell proliferation and the cell cycle, and on microtubule dynamics in vivo and in vitro. Treatment of synchronized leukemia cells with varying concentrations of SP600125 results in significant G2/M cell cycle arrest with elevated p21 levels, phosphorylation of histone H3 within 24 h, and endoreduplication with elevated Cdk2 protein levels after 48 h. SP600125 also induces significant abnormal microtubule dynamics in vivo. High concentrations of SP600125 (200 microMeter) were required to disorganize microtubule polymerization in vitro. Additionally, SP600125-induced delayed apoptosis and cell death was accompanied by significant poly ADP-ribose polymerase (PARP) cleavage and caspase-3 activity in the late phase (at 72 h). Endoreduplication showed a greater increase in ectopic Bcl-2-expressing U937 cells at 72 h than in wild-type U937 cells without delayed apoptosis. These results indicate that Bcl-2 suppresses apoptosis and SP600125-induced G2/M arrest and endoreduplication. Therefore, we suggest that SP600125 induces mitotic arrest by inducing abnormal spindle microtubule dynamics.

Single nucleotide polymorphisms in cell cycle regulator p21 and p27 genes are associated with susceptibility to epithelial ovarian cancer / 中华妇产科杂志

Objective To investigate the association of single nucleotide polymorphisms(SNP)in p21and p27 genes with the risk of epithelial ovarian cancer(EOC).Methods Genotypes were analyzed by polymerase chain reaction-restrictive fragment length polymorphism(PCR-RFLP)method in 234 patients with EOC and 284 control women in China.Results (1)The frequencies of the p21 in healthy controls were 34.2%.49.6%and 16.2%,while the distribution of the C and T allele was 59.0%and 41.0%,respectively.The p21 C/C(28.2%),C/T(53.0%),T/T(18.8%)distribution in ovarian cancer patients was not significantly different from that in healthy controls(P＞0.05).There was no statistic difference in allele distribution between ovarian cancer patients and healthy controls(P＞0.05)either.The stratification analysis by tumor histological type did show that the genotype distribution in four types of ovarian cancer patients was significantly different from that in healthy controls(P=0.02).The C/C genotype was likely to reduce the risk of epithelial endometrial cancer.and the adjusted odds ratio was 0.56(95%CI:0.32-0.98).(2)The genotype frequencies of the p27 in healthy controls were 88.4%,10.9%and 0.7%.while the distribution of the V and G allele was 93.8%and 6.2%.respectively.The V/V(93.6%),V/G(5.1%)and G/G(1.3%)distribution in ovarian cancer patients was significantly different from that in healthy controls(P=0.04).There was no statistic difference in allele distributionbetween ovarian cancer patients and healthy controls(P＞0.05).Compared with the V/G and G/G genotypes,the V/V genotype increased the risk of EOC,the adjusted odds ratio was 1.92(95%CI:1.02-3.63).Conclusion The C/C genotype of p21 may reduce the risk of epithelial endometrial cancer,and the genotype of p27 V/V may be a potential risk factor for susceptibility to EOC.

Transient downregulation of protein O-N-acetylglucosaminylation by treatment of high-dose nicotinamide in human cells

Nicotinamide at millimolar concentrations affects cell survival in various conditions, and is being utilized therapeutically in many human diseases. However, the effect of an acute treatment of nicotinamide at such high dose on gene expression and cellular metabolism has rarely been determined previously. In this study, we found that levels of O-N-acetylglucosamin(O- GlcNAc)ylated proteins including Sp1 acutely decreased upon treatment of 10 mM nicotinamide. Concomitantly, Sp1 protein level decreased rapidly through accelerated proteasome-mediated proteolysis. Cotreatment of glucosamine or 2-deoxyglucose, which inhibits protein deGlcNAcylation, effectively blocked the decrease induced by nicotinamide. Interestingly, the decline in the levels of Sp1 and protein O- GlcNAcylation was only transient lasting for two days post treatment, and this pattern matched closely the rapid fluctuation of the cellular [NAD(+)]. Our results suggest a possible link between cellular nicotinamide metabolism and protein O-GlcNAcylation, and an existence of cellular [NAD(+)] homeostasis.

Trichostatin A-mediated upregulation of p21

Histone deacetylase inhibitors (HDIs), a new class of anti-cancer agents, have been reported to suppress formation of osteoclast precursors and their fusion into multinucleated cells. However, little is known about the effect of HDIs on mature osteoclasts, which may have significance for their therapeutic use. Here, we demonstrate a novel action of HDIs on osteoclast apoptosis. Primary multinucleated mature osteoclasts were prepared from mouse bone marrow cells. Treatment of osteoclasts with the HDI trichostatin A (TSA) caused apoptosis, as confirmed by annexin V staining and caspase activation. TSA caused the upregulation of p21WAF1 in osteoclasts. To understand the role of p21(WAF1) upregulation in TSA-treated osteoclasts, shRNA against p21(WAF1)-containing lentivirus was introduced into osteoclasts. The suppression of p21(WAF1) decreased TSA-directed osteoclast apoptosis. Collectively, our results provide evidence that TSA causes osteoclast apoptosis, which involves, in part, TSA-induced upregulation of p21(WAF1), and strongly supports HDIs as potential therapeutic agents for excessive bone resorption.

Prevalence of p21 immunohistochemical expression in esophageal adenocarcinoma / Prevalência da expressão imunoistoquímica da proteína p21 em adenocarcinoma do esôfago

BACKGROUND: In western societies, the prevalence of adenocarcinoma of the gastroesophageal junction has increased in recent years. It is commonly accepted today that esophageal adenocarcinoma develops from a premalignant lesion: Barrett's esophagus. This type of carcinoma is hardly diagnosed at early stages, which results in significant mortality. Molecular biology studies have shown that most malignant tumors originate from the interaction between inherited characteristics and external factors, which may cause genetic changes that interfere with the control over the differentiation and growth of cells in susceptible individuals. p21 (WAF1/CIP1) has a key role in the regulation of the cell cycle, and its immunohistochemical expression has been investigated in several tumors, showing that it influences the prognosis of various neoplasms. AIM: To check the prevalence of p21 protein expression in patients with esophageal adenocarcinoma diagnosed in the last 5 years by the Group for Surgeries of the Esophagus and Stomach of "Hospital de Clínicas de Porto Alegre", RS, Brazil. METHODS: The study population consisted of 42 patients with esophageal adenocarcinoma diagnosed by the Group for Surgeries of the Esophagus and Stomach between January 1998 and December 2002. The expression of p21 protein was determined by immunohistochemistry using primary antibody, p21, clone SX118, code M7202 (Dako), and assessed according to the immunoreactive scoring system. RESULTS: Of 42 analyzed patients, 83.3 percent were male and older than 40 years. Among these, 56.2 percent were submitted to curative resection: total gastrectomy and transhiatal esophagogastrectomy. The remaining patients were submitted to palliative surgery or did not undergo any surgical treatment. Only five patients received adjuvant chemotherapy and radiation therapy, either alone or combined. Advanced disease (stages III and IV) was detected in 78.6 percent of the patients. Only nine patients were positive for...

RACIONAL: No mundo ocidental, a prevalência de adenocarcinoma da junção esôfago-gástrica vem crescendo nas últimas décadas. Atualmente, é aceito que o adenocarcinoma do esôfago se desenvolve de uma lesão pré-maligna: esôfago de Barrett. Este carcinoma é de difícil diagnóstico nos seus estágios iniciais, o que resulta em mortalidade significativa. O estudo da biologia molecular tem demonstrado que grande parte dos tumores malignos tem origem na interação entre o componente hereditário e influências externas, que em indivíduos predispostos podem ocasionar alterações genéticas que influenciem o controle da diferenciação e crescimento celular. O p21(WAF1/CIP1) tem papel fundamental na regulação do ciclo celular e sua expressão imunoistoquímica tem sido estudada em diversos tumores, mostrando influência no prognóstico de várias neoplasias. OBJETIVO: Verificar a prevalência da expressão da proteína p21 em pacientes com adenocarcinoma de esôfago diagnosticados nos últimos 5 anos no Grupo de Cirurgia de Esôfago e Estômago do Hospital de Clínicas de Porto Alegre, RS (GCEE/HCPA). PACIENTES E MÉTODOS: A população em estudo foi constituída de 42 pacientes com adenocarcinoma de esôfago diagnosticados no GCEE/HCPA entre janeiro de 1998 e dezembro de 2002. A expressão da proteína p21 foi avaliada por meio de imunoistoquímica, com anticorpo primário, p21, clone SX118, código M7202 da DAKO, e quantificada de acordo com o sistema de escore de imunorreatividade ("Immunoreactive scoring system" - IRS). RESULTADOS: Foram estudados 42 pacientes, 83,3 por cento eram do sexo masculino, com idade superior a 40 anos. Destes, 56,2 por cento foram submetidos a procedimentos cirúrgicos com intenção curativa: gastrectomia total e esofagogastrectomia transhiatal. Os demais foram submetidos a cirurgia paliativa ou não sofreram tratamento cirúrgico. Apenas cinco pacientes receberam tratamento adjuvante com quimioterapia e radioterapia, isoladas ou combinadas. Quanto ao estádio, 78,6 por cento ...

Role of p21CIP1 as a determinant of SC-560 response in human HCT116 colon carcinoma cells

SC-560, a strucutral analogue of celecoxib, induces growth inhibition in a wide range of human cancer cells in a cyclooxygenase (COX)-independent manner. Since SC-560 suppresses the growth of cancer cells mainly by inducing cell cycle arrest, we sought to examine the role of p21CIP1, a cell cycle regulator protein, in the cellular response against SC-560 by using p21(+/+)and p21(-/-)isogenic HCT116 colon carcinoma cells. In HCT116 (p21(+/+)) cells, SC-560 dose-dependently induced growth inhibition and cell cycle arrest at the G1 phase without significant apoptosis induction. SC-560-induced cell cycle arrest was accompanied by upregulation of p21CIP1. However, the extent of SC-560-induced accumulation at the G1 phase was approximately equal in the p21(+/+)and the p21(-/-)cells. Nonetheless, the growth inhibition by SC-560 was increased in p21(-/-)cells than p21(+/+)cells. SC-560-induced reactive oxygen species (ROS) generation did not differ between p21(+/+)and p21(-/-)cells but the subsequent activaton of apoptotic caspase cascade was more pronounced in p21(-/-)cells compared with p21(+/+)cells. These results suggest that p21CIP1 blocks the SC-560-induced apoptotic response of HCT116 cells. SC-560 combined with other therapy that can block p21 CIP1 expression or function may contribute to the effective treatment of colon cancer.

The Effects of p21 on Bladder Cancers / 대한비뇨기과학회지

Purpose: p21 protein is an inhibitor of cyclin-dependent kinases, which may be able to arrest the cell cycle at the G1 phase by inhibiting DNA replication through the interaction with proliferating cell nuclear antigen. From experimental studies, p21 has been considered a tumor suppressor gene. Herein, the effects of p21 on the development, stage, grade, recurrence, progression and patient's survival in human bladder cancers were evaluated. Materials and Methods: The mRNA expression levels of p21 were examined in 149 tumor specimens obtained from patients with primary bladder cancer and in 18 normal bladder mucosae using real-time polymerase chain reaction (PCR). Results: p21 was significantly expressed in human bladder tumor tissues at high levels (7.11+/-0.69pg/ml), but was not expressed in the normal bladder mucosae. Compared with invasive bladder cancer (5.03+/-0.95), the p21 expression levels were significantly enhanced in superficial bladder cancer (7.96+/-0.88pg/ml) (p=0.0250); whereas, the grade was not related to the expression of p21. The levels of p21 expression were enhanced in non-recurred (9.33+/-1.38) and non-progressed (8.13+/-0.86) compared with recurred (6.03+/-0.75) and progressed (3.67+/-0.52) patients (each p<0.05). The level of p21 expression was significantly correlated with the disease free survival in patients the bladder cancers. Conclusions: The enhanced expression of p21 is strongly associated with the development of bladder cancer. Moreover, increased expressions of p21 are also positively associated with the low rate of recurrence and progression of bladder cancer. Conversely, an enhanced expression of p21 provides a survival benefit for patients with bladder cancer. These results suggest that p21 might be useful as a marker in assessing tumor diagnosis, recurrence, progression and the survival in human bladder cancer patients.

Low-dose radiation response of the p21(WAF1/CIP1) gene promoter transduced by adeno-associated virus vector

In cancer gene therapy, restriction of antitumor transgene expression in a radiation field by use of ionizing radiation-inducible promoters is one of the promising approaches for tumor-specific gene delivery. Although tumor suppressor protein p53 is induced by low doses (<1 Gy) of radiation, there have been only a few reports indicating potential utilization of a p53-target gene promoter, such as that of the p21 gene. This is mainly because the transiently transfected promoter of p53-target genes is not much sensitive to radiation. We examined the response of the p21 gene promoter to low-dose radiation when transduced into a human breast cancer cell line MCF-7 by use of recombinant adeno-associated virus (rAAV) vectors. It was shown that the p21 gene promoter transduced by rAAV vectors was more highly radiation-responsive than that transiently transfected by electroporation. A significant induction of the p21 gene promoter by radiation of low doses down to 0.2 Gy was observed. When cells were transduced with the p21 gene promoter-driven HSVtk gene by rAAV vector, they were significantly sensitized to repetitive treatment with low dose radiation (1 Gy) in the presence of the prodrug ganciclovir. It was therefore considered that the p21 gene promoter in combination with a rAAV vector is potentially usable for the development of a low-dose radiation-inducible vector for cancer gene therapy.