Reduced glucose concentration enhances ultradian rhythms in Pdcd5 promoter activity in vitro.

Intrinsically driven ultradian rhythms in the hourly range are often co-expressed with circadian rhythms in various physiological processes including metabolic processes such as feeding behaviour, gene expression and cellular metabolism. Several behavioural observations show that reduced energy intake or increased energy expenditure leads to a re-balancing of ultradian and circadian timing, favouring ultradian feeding and activity patterns when energy availability is limited. This suggests a close link between ultradian rhythmicity and metabolic homeostasis, but we currently lack models to test this hypothesis at a cellular level. We therefore transduced 3T3-L1 pre-adipocyte cells with a reporter construct that drives a destabilised luciferase via the Pdcd5 promotor, a gene we previously showed to exhibit robust ultradian rhythms in vitro. Ultradian rhythmicity in Pdcd5 promotor driven bioluminescence was observed in >80% of all cultures that were synchronised with dexamethasone, whereas significantly lower numbers exhibited ultradian rhythmicity in non-synchronised cultures (∼11%). Cosine fits to ultradian bioluminescence rhythms in cells cultured and measured in low glucose concentrations (2 mM and 5 mM), exhibited significantly higher amplitudes than all other cultures, and a shorter period (6.9 h vs. 8.2 h, N = 12). Our findings show substantial ultradian rhythmicity in Pdcd5 promotor activity in cells in which the circadian clocks have been synchronised in vitro, which is in line with observations of circadian synchronisation of behavioural ultradian rhythms. Critically, we show that the amplitude of ultradian rhythms is enhanced in low glucose conditions, suggesting that low energy availability enhances ultradian rhythmicity at the cellular level in vitro.

PDCD5 as a Potential Biomarker for Improved Prediction of the Incidence and Remission for Patients with Rheumatoid Arthritis.

INTRODUCTION: Rheumatoid arthritis (RA) often involves an altered T-cell subpopulation, higher levels of inflammatory cytokines, and auto-antibodies. This study investigated whether PDCD5 could be a biomarker to predict the incidence and remission of RA so as to guide the therapeutic management of clinical RA. METHODS: One hundred fifty-two patients (41 being in both active status and stable remission status) who were newly diagnosed with RA and 38 healthy controls were enrolled. Basic clinical data were collected before using blood samples remaining in the clinic after routine complete blood count. The ability of PDCD5 and important indicators to predict the remission of RA was estimated based on receiver operating characteristic curve (ROC) analysis. RESULTS: PDCD5 expression was found to be significantly increased in RA patients in active status in comparison with healthy controls or those in stable remission status. Compared with anti-CCP, ESR and DAS28 score, PDCD5 was of better predictive value with an AUC of 0.846 (95% CI 0.780-0.912) for RA remission. The incidence risk of RA increased with higher levels of PDCD5 (OR = 1.73, 95% CI = 1.45-1.98, P = 0.005) in multiple logistic regression analysis, with the risk increasing by 2.94-times for high-risk group in comparison with low-risk group (OR = 2.94, 95% CI = 2.35-4.62, P < 0.001). The association between PDCD5 and RA remission showed a similar result. For correlation analysis, significant associations were eventually found between PDCD5 and indicated genes (FOXP3, TNF-α, IL-17A, IFN-γ and IL-6) as well as several important clinical parameters including IgG, RF, CRP, ESR, anti-CCP and DAS28 score. CONCLUSIONS: This study suggested that increased PDCD5 expression was significantly linked to the incidence and remission of RA. PDCD5 may be used as a novel biomarker for the prediction of RA incidence and remission, especially due to its potential involvement in the development of the condition.

Muscle-specific programmed cell death 5 deletion attenuates cardiac aging.

Programmed cell death 5 (PDCD5) is a tumor suppressor gene that regulates the cell cycle, apoptosis and immune responses. However, the physiological function of Pdcd5 in cardiac aging remains unknown. We find that Pdcd5 mRNA and protein levels were significantly increased in the heart of mice with age. Therefore, we hypothesize that Pdcd5 regulates cardiac aging. To test the hypothesis, we generated muscle-specific Pdcd5-deficient mice. Mature adult Pdcd5-deficient mice had normal cardiac morphology and function. In naturally aged mice, Pdcd5 deficiency alleviated age-related cardiac phenotypes including reduced fibrosis and suppressed cardiomyocyte hypertrophy. Moreover, muscle-specific Pdcd5 deficiency attenuated cellular senescence in the heart as demonstrated by decreased number of senescence-associated ß-galactosidase-positive cells, diminished p53, p21 and p16 expression, and reduced the senescence-associated secretory phenotype. Apoptotic cell death was reduced by Pdcd5 deficiency in the heart as revealed by terminal deoxynucleotidyl transferase dUTP nick end labeling assay, which was coincident with diminished Bcl-2-associated X protein, and enhanced B-cell lymphoma 2 and X-linked inhibitor of apoptosis protein expression. Mitochondrial quality in cardiomyocytes was improved by Pdcd5 deficiency through increased Parkin-mediated mitophagy. In addition, Pdcd5 deficiency alleviated doxorubicin-induced premature cellular senescence and cardiac aging. Furthermore, Pdcd5 protein abundance was significantly correlated with p53 protein abundance, and Pdcd5 interacted with p53 in the heart. Taken together, our results reveal that Pdcd5 deficiency attenuates cardiac aging by reducing cellular senescence and apoptosis, and increasing Parkin-mediated mitophagy, likely through p53. Pdcd5 is a novel regulator of cardiac aging and a potential therapeutic target.

Programmed cell death 5 improves skeletal muscle insulin resistance by inhibiting IRS-1 ubiquitination through stabilization of MDM2.

AIMS: Insulin resistance is defined as the decreased sensitivity of tissues and organs to insulin and it is the main pathological basis of metabolic syndrome. PDCD5 is widely expressed in tissues including skeletal muscle and liver, but its exact function and the role in insulin resistance has not been studied. The present study is to explore the effect of PDCD5 on insulin resistance in skeletal muscle, the largest target organ of insulin, and its mechanism. MATERIALS AND METHODS: Mice were fed with high-fat diet to establish obesity model. C2C12 myoblasts differentiated into myotubes and then were treated with palmitate to induce insulin resistance. Gain-of-function and loss-of-function experiments were performed by infecting C2C12 with adenovirus containing PDCD5 cDNA or PDCD5 shRNA. KEY FINDINGS: PDCD5 protein was first increased and then decreased in the skeletal muscle from high-fat diet induced obese mice and consistently in palmitate induced insulin resistance C2C12 myotubes. Overexpression of PDCD5 in C2C12 cells did not affect the sensitivity to insulin but inhibited the palmitate induced insulin resistance, while knockdown of PDCD5 aggravated the insulin resistance. Mechanistically, PDCD5 interacted with ubiquitin ligase MDM2; overexpression of PDCD5 decreased MDM2 protein level, inhibited the increased interaction of MDM2 with IRS-1 and the degradation of IRS-1 by palmitate stimulation. SIGNIFICANCE: PDCD5 is upregulated during the early stage of insulin resistance in skeletal muscle. The increased PDCD5 inhibits IRS-1 ubiquitination, increases the stability of IRS-1 by interacting with and degrading MDM2, thus providing a protective effect on insulin resistance in skeletal muscle.

NMR resonance assignments of the programmed cell death protein 5 (PDCD5) from Toxoplasma gondii.

Toxoplasmosis is a systematic protozoan disease caused by a tiny parasite Toxoplasma gondii. The infection can be dangerous for pregnant woman and people with weak immune systems. The secreted protein named TgPDCD5 (Programmed cell death protein 5 from Toxoplasma gondii) plays an important role in apoptosis-inducing effect on host cells. Here, we report the 1H, 13C, and 15N resonance assignments of TgPDCD5. This work provides the ground for further structural elucidate and biophysical investigation about protein function.

MicroRNA-766 Promotes The Proliferation, Migration And Invasion, And Inhibits The Apoptosis Of Cutaneous Squamous Cell Carcinoma Cells By Targeting PDCD5.

PURPOSE: This study aimed to investigate the regulatory role and mechanism of microRNA-766 (miR-766) on cutaneous squamous cell carcinoma (CSCC) cells. METHODS: The expression of miR-766 and programmed cell death 5 (PDCD5) was detected in CSCC tissues and CSCC cell lines (A431, SCL-1 and DJM-1 cells) by qRT-RCR. The proliferation, colony-forming ability, apoptosis, migration and invasion of A431 and SCL-1 cells was measured by MTT, colony formation, flow cytometry, wound healing and transwell assay, respectively. The interaction between miR-766 and PDCD5 was detected by dual-luciferase reporter gene assay. The expression of matrix metalloproteinase 2 (MMP-2), MMP-9 and PDCD5 was measured by Western blot. In addition, A431 cells were subcutaneously injected into mice, and the tumor volume and weight were measured. RESULTS: MiR-766 was upregulated, and PDCD5 was downregulated in CSCC tissues and cells. MiR-766 significantly promoted the proliferation, migration and invasion, and inhibited the apoptosis of A431 and SCL-1 cells. MiR-766 also significantly increased the expression of MMP-2 and MMP-9 in A431 and SCL-1 cells. PDCD5 was a target gene of miR-766. PDCD5 significantly reversed the tumor-promoting effect of miR-766 on A431 and SCL-1 cells. In addition, miR-766 inhibitor inhibited the tumor growth in mice. CONCLUSION: MiR-766 inhibitor inhibited the proliferation, migration and invasion, and promoted the apoptosis of CSCC cells via downregulating PDCD5.

OTU deubiquitinase 5 inhibits the progression of non-small cell lung cancer via regulating p53 and PDCD5.

Non-small cell lung cancer (NSCLC) has the highest morbidity and mortality worldwide. OTU deubiquitinase 5 (OTUD5), a deubiquitinating enzyme, can enhance the stability of p53 and programmed cell death 5 (PDCD5), a protein related to the apoptosis, by deubiquitination. This study aimed to explore the biological function and underlying mechanism of OTUD5 in NSCLC. Western blot and qRT-PCR were used to detect the expression of OTUD5 protein and mRNA in NSCLC tissues and cells, respectively. RNAi was adopted to construct an OTUD5 low-expression model while the plasmids overexpressing p53 and PDCD5 were used to establish the overexpression models, respectively. CCK-8 assay, transwell assay, and apoptosis assay were carried out to analyze the changes in the proliferation, migration, and chemoresistance of A549 and HCC827 cells. The mechanism of OTUD5 in NSCLC was studied by Western blot. Down-regulated OTUD5 in NSCLC tissues was significantly correlated to a poor prognosis. The knockdown of OTUD5 inactivated p53 and PDCD5, promoting the proliferation and metastasis of NSCLC cells while inhibiting their apoptosis. OTUD5 knockdown also enhanced the resistance of NSCLC cells to doxorubicin and cisplatin. OTUD5 acted as a tumor suppressor in NSCLC by regulating the p53 and PDCD5 pathways.

miR-423-5p enhances chemoresistance of glioblastomas cells to temozolomide by regulating PDCD5 / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To investigate the miR-423-5p expression in brain glioma tissues and cell lines, and its promotive effect on temozolomide (TMZ) chemoresistance by targeting PDCD5 (programmed cell death protein 5). Methods: Tumor tissues and matched peritumoral tissues were collected from 20 brain glioma patients who were surgically treated in the Department of Neurosurgery, Affiliated Hospital of Beihua University between January 2017 and December 2018. Glioblastoma cell lines (U251, U87, SHG-44) and human normal glial cell line HMC-3 were also used in the study. The relative expression of miR-423-5p and PDCD5 in brain glioma and peritumoral tissues and cell lines was detected by qPCR. The synthesized miR-423-5p mimics and miR-NC were respectively transfected into U251 and U87 cells; meanwhile, TMZ at different concentrations (50, 100, 150 and 200 μmol/L) were also used to treat the cells. Then, the chemoresistance of cells to TMZ were determined. MTT assay and colony formation assay were used to examine the proliferation of U251 and U87 cells, andWestern blotting was used to detect the expression of c-caspase 3, Bcl-2 and PDCD5 proteins in U251 and U87 cells. The targeting relationship between PDCD5 and miR-423-5p was validated through Dual luciferase reporter gene assay. Results: miR-423-5p was highly expressed in glioma tissues and glioma cell lines (all P<0.01). As compared with the miR-NC group, the proliferation and TMZ-chemoresistance of U251 and U87 cells in miR-423-5p mimics group significantly increased (all P<0.01). Dual luciferase reporter gene assay validated that miR-423-5p could bind with PDCD5 3' UTR to suppress the expression of PDCD5. Conclusion: High expression of miR-423-5p enhances the chemoresistance of glioma cells to TMZ, and miR-423-5p may serve as a potential therapeutic target in the treatment of brain glioma.

Clinicopathological Significance of Decreased Expression of the Tumor Inhibitor Gene PDCD5 in Osteoclastoma.

Background: The gene programmed cell death 5 (PDCD5) has recently been characterized as a tumor suppressor gene and is believed to be an important prognostic cancer marker; it is frequently involved in neoplastic transformation and apoptosis of tumor cells. Several studies have demonstrated a decrease or loss of expression of PDCD5 in certain tumors. However, the relevance of PDCD5 expression in human osteoclastoma and its clinicopathological significance have not been extensively studied. Methods: The aim of this study was to explore the relative transcriptional and translational expression levels of PDCD5 in 79 osteoclastoma samples using multi-modal methods of analysis. Results: Our findings showed that 52% (15/29) of osteoclastoma cases exhibited reduced PDCD5 expression at the transcriptional level, and 56% (44/79) exhibited lower PDCD5 expression at the protein level, when compared with nontumor tissue. In addition, the statistical significance of the altered PDCD5 protein expression was examined using the Campanacci grading system for osteoclastoma. More importantly, the decreased expression at the translational level was observed to have a negative association with the Ki-67 staining index. Conclusion: Based on these findings, abnormal PDCD5 expression might be an important biomarker in human osteoclastoma and may contribute to tumor progression and malignant cell proliferation.

[rhPDCD5 suppresses pro-inflammatory cytokine secretion and proliferation and induces apoptosis of activated lymphocytes from rats with collagen-induced arthritis].

OBJECTIVE: To investigate the effect of recombinant human PDCD5 (rhPDCD5) treatment in a rat model of bovine II collagen (CII)-induced arthritis (CIA) on inflammatory cytokine secretion, proliferation and apoptosis of activated lymphocytes and explore the mechanisms of rhPDCD5-induced immunosuppression on activated lymphocytes. METHODS: Female Wistar rats were randomly divided into normal control group, CIA+ ovalbumin (OVA) group, CIA+ rhTNFR: Fc group, and CIA+rhPDCD5 group. The rats in the latter 3 groups received intraperitoneal injections of OVA (14 mg/kg), rhTNFR: Fc (3.5 mg/kg) or rhPDCD5 (14 mg/kg) from day 2 to day 26 following CII injection. On day 28, the spleens of the rats were harvested for preparing single cell suspensions of splenocytes, which were activated by CII (20µg/mL) or anti-CD3 (1µg/mL)+ anti-CD28 (2µg/mL) for 48 h and 72 h. The production of interferon-γ(IFN-γ) and interleukin-17A (IL-17A) by the activated lymphocytes was determined by ELISA of the culture supernatants. The proliferation and apoptosis of the activated lymphocytes were assessed using [3H]-thymidine incorporation assay and flow cytometry, respectively. RESULTS: Compared with those in CIA + OVA group, IFN-γand IL-17A secretions by the activated lymphocytes from rhPDCD5-treated CIA rats significantly decreased. RhPDCD5 treatment of the CIA rats obviously suppressed the proliferation and promoted apoptosis of the lymphocytes activated by CII or by anti-CD3 + anti-CD28. CONCLUSIONS: rhPDCD5 reduces pro-inflammatory cytokine secretion, inhibits the proliferation and promotes activation-induced cell death of activated CD4 + lymphocytes to produce immunosuppression in rat models of CIA.

Lgr5-mediated p53 Repression through PDCD5 leads to doxorubicin resistance in Hepatocellular Carcinoma.

The devastating prognosis of hepatocellular carcinoma (HCC) is partially attributed to chemotherapy resistance. Accumulating evidence suggests that the epithelial-mesenchymal transition (EMT) is a key driving force of carcinoma metastasis and chemoresistance in solid tumors. Leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5), as an EMT inducer, is involved in the potentiation of Wnt signaling in HCC. This study proposes uncovering the roles of Lgr5 in Doxorubicin (Dox) resistance of HCC to improve treatment efficacy for HCC. Methods: We investigated the expression and significance of Lgr5 in HCC tissue and different cell lines. The effect of Lgr5 in EMT and Dox resistance was analyzed in HCC cells and implanted HCC tumor models. A two-hybrid analysis, using the Lgr5 gene as the bait and a HCC cDNA library, was used to screen targeted proteins that interact with Lgr5. The positive clones were identified by coimmunoprecipitation (Co-IP) and Glutathione-S-transferase (GST) pull-down. The impact of the interaction on Dox resistance was investigated by a series of assays in vitro and in vivo . Result: We found that Lgr5 was upregulated and positively correlated with poor prognosis in HCC. Additionally, it functioned as a tumor promoter to increase cell migration and induce EMT in HCC cells and increase the resistance to Dox. We identified programmed cell death protein 5 (PDCD5) as a target gene of Lgr5 and we found that PDCD5 was responsible for Lgr5-mediated Dox resistance. Further analysis with Co-IP and GST pull-down assays showed that the N-terminal extracellular domain of Lgr5 could directly bind to PDCD5. Lgr5 induced p53 degradation by blocking the nuclear translocation of PDCD5 and leading to the loss of p53 stabilization. Lgr5 showed a protection against the inhibition of Dox on the growth of tumor subcutaneously injected. Moreover, Lgr5 suppressed Dox-induced apoptosis via the p53 pathway and attenuated the cytotoxicity of Dox to HCC. Conclusion: Lgr5 induces the EMT and inhibits apoptosis, thus promoting chemoresistance by regulating the PDCD5/p53 signaling axis. Furthermore, Lgr5 may be a potential target gene for overcoming Dox resistance.

PDCD5 inhibits osteosarcoma cell metastasis via targeting TGF-ß1/Smad signaling pathway and is associated with good prognosis.

Whether programmed cell death 5 (PDCD5) is effective for tumor metastasis remains unclear. In this study, the expression of PDCD5 in 63 osteosarcoma (OS) tissues and two OS cell lines was analyzed. Then the relationship between PDCD5 expression and clinicopathological features of OS was studied. In addition, adhesion, wound healing, Transwell and Matrigel tube formation assays were used to explore the role of PDCD5 in OS cell adhesion, migration, invasion and angiogenesis. Western blotting was used to detect the protein expression of TGF-ß1/Smad signaling pathway and epithelial-mesenchymal transition (EMT)-related markers. At the same time, key molecules involved in migration, invasion and EMT in tumor specimens were assessed by immunohistochemistry. The data showed that PDCD5 overexpression significantly attenuated OS cell adhesion, migration, invasion and angiogenesis. Furthermore, PDCD5 knockdown caused an opposite effect on these phenotypes in vitro. PDCD5 inhibited tumor metastasis by attenuating EMT in OS cells. PDCD5 knockdown enhanced the incidence of metastasis and EMT in OS cells. Furthermore, PDCD5 expression was reduced by transforming growth factor-ß1 (TGF-ß1) in a time-dependent manner, and TGF-ß1-induced EMT was induced by PDCD5 knockdown. Inactivation of the TGF-ß1/Smad signaling pathway was involved in the anti-tumor function of PDCD5 in OS. Furthermore, tumor progression in OS patients was associated with low expression of PDCD5, indicating a decrease in survival and a poor prognosis. Our results suggest that PDCD5 may attenuate EMT by inhibiting TGF-ß1/Smad signaling pathway to inhibit OS metastasis and may be a potential adjuvant genetic therapy for OS.

Serine/threonine kinase 31 promotes PDCD5-mediated apoptosis in p53-dependent human colon cancer cells.

Although programed cell death 5 (PDCD5) is an important protein in p53-mediated proapoptotic signaling, very little is known about PDCD5-related cell death. In this study, we report that serine/threonine kinase 31 (STK31) interacts with PDCD5, which maintains the stability of PDCD5. STK31 overexpression significantly activated PDCD5 stabilization and p53-mediated apoptosis in response to etoposide (ET). However, STK31 knockdown did not enhance apoptosis by ET treatment. Moreover, when STK31 was depleted, PDCD5 inhibited the activation of the p53 signaling pathway with ET, indicating that the PDCD5-STK31 network has an essential role in p53 activation. Importantly, STK31 activated the p53 signaling pathway by genotoxic stress through positive regulation of PDCD5-mediated apoptosis. We thus demonstrated that overexpression of STK31 greatly inhibited tumorigenic growth and increased the chemosensitivity of HCT116 human colorectal carcinoma cells. Taken together, these findings demonstrate that the STK31-PDCD5 complex network regulates apoptosis of cancer cells, and STK31 is a positive apoptosis regulator that inhibits tumorigenesis of colon cancer cells by inducing PDCD5-mediated apoptosis in response to genotoxic stress.

rhPDCD5 suppresses pro-inflammatory cytokine secretion and proliferation and induces apoptosis of activated lymphocytes from rats with collagen-induced arthritis / 南方医科大学学报

OBJECTIVE@#To investigate the effect of recombinant human PDCD5 (rhPDCD5) treatment in a rat model of bovine II collagen (CII)-induced arthritis (CIA) on inflammatory cytokine secretion, proliferation and apoptosis of activated lymphocytes and explore the mechanisms of rhPDCD5-induced immunosuppression on activated lymphocytes.@*METHODS@#Female Wistar rats were randomly divided into normal control group, CIA+ ovalbumin (OVA) group, CIA+ rhTNFR: Fc group, and CIA+rhPDCD5 group. The rats in the latter 3 groups received intraperitoneal injections of OVA (14 mg/kg), rhTNFR: Fc (3.5 mg/kg) or rhPDCD5 (14 mg/kg) from day 2 to day 26 following CII injection. On day 28, the spleens of the rats were harvested for preparing single cell suspensions of splenocytes, which were activated by CII (20μg/mL) or anti-CD3 (1μg/mL)+ anti-CD28 (2μg/mL) for 48 h and 72 h. The production of interferon-γ(IFN-γ) and interleukin-17A (IL-17A) by the activated lymphocytes was determined by ELISA of the culture supernatants. The proliferation and apoptosis of the activated lymphocytes were assessed using [H]-thymidine incorporation assay and flow cytometry, respectively.@*RESULTS@#Compared with those in CIA + OVA group, IFN-γand IL-17A secretions by the activated lymphocytes from rhPDCD5-treated CIA rats significantly decreased. RhPDCD5 treatment of the CIA rats obviously suppressed the proliferation and promoted apoptosis of the lymphocytes activated by CII or by anti-CD3 + anti-CD28.@*CONCLUSIONS@#rhPDCD5 reduces pro-inflammatory cytokine secretion, inhibits the proliferation and promotes activation-induced cell death of activated CD4 lymphocytes to produce immunosuppression in rat models of CIA.

Over-expression of programmed cell death 5 gene enhances chemosensitivity of brain glioma cells to temozolomide / 中国肿瘤生物治疗杂志

@# Objective: To explore the role of tumor suppressor gene programmed cell death 5 gene (PDCD5) in the growth and temozolomide (TMZ) sensitivity of brain glioma cells. Methods:Atotal of 116 patients with cerebral glioma admitted to the Department of Neurosurgery, First Clinical Hospital of Jilin University from January 2009 to December 2014 were enrolled in this study. QPCR, WB and immunohistochemistry method were used to detect the mRNAand protein expressions of PDCD5 in glioma cell lines (U87, U251), U87 cell line with stable PDCD5 expression (U87-PDCD5), glioma cells with si-PDCD5 transfection and primary cerebral glioma tissues, respectively. MTT assay was used to detect the effect of over-expression or knockdown of PDCD5 on the growth and TMZ-sensitivity of glioma cells. The subcutaneous tumor-bearing model of glioma cell line U87 was established in nude mice, and then the experimental mice were randomly divided into control group, TMZ group, PDCD5 group and TMZ+exogenous PDCD5 recombinant expression vector group.After 20 days, the animals were sacrificed by cervical dislocation and the tumor tissue was excised to measure the tumor volume and weigh. The expression of PDCD5 in tumor tissues was detected by qPCR and WB methods, and the effects of PDCD5 combined with TMZ on the growth of gliomas were also analyzed. Results: The relative mRNA and protein expressions of PDCD5 in U87 cells were significantly lower than those in U251 cells (both P<0.05), and the mRNA and protein expressions of PDCD5 in high level glioma tissues were significantly lower than those in low level tissues (all P<0.05). The sensitivity of U87-PDCD5 cells and U251 cells to TMZ was higher than that of U87 cells (all P<0.05). The sensitivity of cells to TMZ in U87-PDCD5-siRNA group and U251siRNA group was significantly lower than that of the control group (both P<0.05). The tumor volume and weigh to fnudemicexenografts were compared,and the results showed control group>TMZ group>PDCD 5group>combined group(allP<0.05);however, the mRNA and protein expressions of PDCD5 in the transplanted tumor tissues of each group showed the opposite trend (all P<0.05). Conclusion: PDCD5 over-expression can enhance the chemosensitivity of braingliomato the chemotherapy drug TMZ, while silencing of PDCD5 expression exertsthe opposite effect.The combination of PDCD5 and TMZ can better inhibit the growth of xenografts in nude mice.

Synergistic antitumoral efficacy of a novel replicative adenovirus SG611-PDCD5 and daunorubicin in human leukemic cells.

BACKGROUND: Daunorubicin is a traditional chemotherapeutic agent that plays a pivotal role in leukemia therapy. However, the dose-related toxicity remains a considerable challenge. The apoptosis-regulating gene, PDCD5, is downregulated in various tumors, including leukemias, and may provide a potential target for the diagnosis and treatment of leukemia. The purpose of this study was to construct a triple-regulated oncolytic adenovirus carrying a PDCD5 gene expression cassette (SG611-PDCD5) and explore the combined antitumor efficacy of SG611-PDCD5 in combination with low dose daunorubicin on leukemic cells. MATERIALS AND METHODS: A variety of leukemic cell lines, including K562, MEG-01, KG-1a, HL-60, SUP-B15, and BV-173, were cultured according to the providers' instructions. The insertion and orientation of all recombined plasmids were confirmed by restriction enzyme digestion and PCR. The tumor-selective replication of the constructed conditionally replicating SG611-PDCD5 and its antitumor efficacy in combination with daunorubicin were characterized in leukemic cell lines in vitro and in a nude mouse xenograft model. Cell viability was detected using cell-counting kit-8. Apoptosis was detected in whole living cells using flow cytometry and in paraffin-embedded tumor tissues using a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. RESULTS: The triple-regulated CRAd carrying SG611-PDCD5 and nude mouse xenograft models of K562 cells were successfully constructed. In vitro treatment with SG611-PDCD5 in combination with low-dose daunorubicin elicited more potent anti-proliferative and proapoptotic effects in leukemic cells in a dose-dependent manner. The Chou-Talalay analysis revealed synergistic anti-proliferative effects in all of the above cell lines. In the nude mice xenograft model, the tumor size in the control, daunorubicin, SG611-PDCD5, and combined treatment groups on day 10 were 170.1±47.8, 111.9±81.1, 60.7±12.3, and 33.2±17.5 mm3, respectively (all P<0.05). The results of the TUNEL assay showed significantly more apoptotic cells in the SG611-PDCD5 plus daunorubicin group than in the SG611-PDCD5 or daunorubicin groups alone (25±0.82, 12.5±2.27, and 7.8±2.67 apoptotic cells/field, respectively) (P<0.05). CONCLUSION: The findings suggest that combined treatment with SG611-PDCD5 and daunorubicin may be a promising strategy for enhancing chemosensitivity and thus lowering the dose-related toxicity of daunorubicin in leukemia therapy.

Downregulated PITX1 Modulated by MiR-19a-3p Promotes Cell Malignancy and Predicts a Poor Prognosis of Gastric Cancer by Affecting Transcriptionally Activated PDCD5.

BACKGROUND/AIMS: PITX1 has been identified as a potential tumor-suppressor gene in several malignant tumors. The molecular mechanism underlying PITX1, particularly its function as a transcription factor regulating gene expression during tumorigenesis, is still poorly understood. METHODS: The expression level and location of PITX1 were determined by quantitative reverse transcription PCR (qRT-PCR) and immunohistochemical staining in gastric cancer (GC). The effect of PITX1 on the GC cell proliferation and tumorigenesis was analyzed in vitro and in vivo. To explore how PITX1 suppresses cell proliferation, we used PITX1-ChIP-sequencing to measure genome-wide binding sites of PITX1 and assessed global function associations based on its putative target genes. ChIP-PCR, electrophoretic mobility shift assay, and promoter reporter assays examined whether PITX1 bound to PDCD5 and regulated its expression. The function of PDCD5 in GC cell apoptosis was further examined in vitro and in vivo. The relationship between the PITX1 protein level and GC patient prognosis was evaluated by the Kaplan-Meier estimator. Meanwhile, the expression level of miR-19a-3p, which is related to PITX1, was also detected by luciferase reporter assay, qRT-PCR, and western blotting. RESULTS: The expression level of PITX1 was decreased in GC tissues and cell lines. Elevated PITX1 expression significantly suppressed the cell proliferation of GC cells and tumorigenesis in vitro and in vivo. PITX1 knockdown blocked its inhibition of GC cell proliferation. PITX1 bound to whole genome-wide sites, with these targets enriched on genes with functions mainly related to cell growth and apoptosis. PITX1 bound to PDCD5, an apoptosis-related gene, during tumorigenesis, and cis-regulated PDCD5 expression. Increased PDCD5 expression in GC cells not only induced GC cell apoptosis, but also suppressed GC cell growth in vitro and in vivo. Moreover, PITX1 expression was regulated by miR-19a-3p. More importantly, a decreased level of PITX1 protein was correlated with poor GC patient prognosis. CONCLUSION: Decreased expression of PITX1 predicts shorter overall survival in GC patients. As a transcriptional activator, PITX1 regulates apoptosis-related genes, including PDCD5, during gastric carcinogenesis. These data indicate PDCD5 to be a novel and feasible therapeutic target for GC.

Programmed cell death 5 suppresses AKT-mediated cytoprotection of endothelium.

Programmed cell death 5 (PDCD5) has been associated with human cancers as a regulator of cell death; however, the role of PDCD5 in the endothelium has not been revealed. Thus, we investigated whether PDCD5 regulates protein kinase B (PKB/AKT)-endothelial nitric oxide synthase (eNOS)-dependent signal transduction in the endothelium and affects atherosclerosis. Endothelial-specific PDCD5 knockout mice showed significantly reduced vascular remodeling compared with wild-type (WT) mice after partial carotid ligation. WT PDCD5 competitively inhibited interaction between histone deacetylase 3 (HDAC3) and AKT, but PDCD5L6R, an HDAC3-binding-deficient mutant, did not. Knockdown of PDCD5 accelerated HDAC3-AKT interaction, AKT and eNOS phosphorylation, and nitric oxide (NO) production in human umbilical vein endothelial cells. Moreover, we found that serum PDCD5 levels reflect endothelial NO production and are correlated with diabetes mellitus, high-density lipoprotein cholesterol, and coronary calcium in human samples obtained from the cardiovascular high-risk cohort. Therefore, we conclude that PDCD5 is associated with endothelial dysfunction and may be a novel therapeutic target in atherosclerosis.

PDCD5 regulates cell proliferation, cell cycle progression and apoptosis.

Programmed cell death (PDCD)5 is cloned from human leukemia cell line TF-1. PDCD5 is one of the members of the programmed cell death protein family that is frequently involved in tumor growth and apoptosis. To investigate the molecular and cellular functions of PDCD5, the present study established a PDCD5 stably overexpressing A431 cell line and examined the role of PDCD5 in cell proliferation, cell cycle progression and apoptosis. The data demonstrated that overexpression of PDCD5 significantly inhibited cell proliferation, induced cell cycle arrest at G2/M phase and apoptosis in A431 cells. The expression profiles of certain key regulators of these cellular events were further investigated, including P53, B cell lymphoma (BCL)-2, BCL-2 associated X protein (BAX) and caspase (CASP)3. The data demonstrated that at the transcript and protein levels, P53, BAX and CASP3 were all upregulated in the PDCD5 stably overexpressing A431 cells whereas BCL-2 was downregulated, indicating that PDCD5 acts as an important upstream regulator of P53, BCL-2, BAX and CASP3. The data suggest that PDCD5 regulates cell proliferation, cell cycle progression and apoptosis in A431 cells. PDCD5 may be a novel tumor suppressor gene, and may be potentially used for cancer treatment in the future.

Treatment of paclitaxel combined with oxaliplatinchemotherapy to the non-small cell lung cancer mouse model / 基础医学与临床

Objective To investigate the therapeutic effect of paclitaxel plus oxaliplatin chemotherapy to the transplanted non-small cell lung cancer of nude mice and the effect to the apoptosis protein expression of PDCD5 and XIAP with mice model.Methods A tumor-bearing mice were randomly divided into blank group, normal saline group, oxaliplatin group, paclitaxel group, paclitaxel plus oxaliplatin group.The gene expression of PDCD5 and XIAP was assayed by real-time quantitative PCR(q-PCR).The apoptosis related PDCD5 and XIAP protein were detected by Western blot.Finally, the tumor weight of each group was measured for statistical analysis.ResultsThe mRNA expression of PDCD5 was highest and the gene expression of XIAP was lowest in paclitaxel plus oxaliplatin group(P<0.01).The expression of PDCD5 protein was highest and the expression of XIAP protein was lowest in paclitaxel plus oxaliplatin group (P<0.01).Finally, compare the tumor weight of each group, paclitaxel plus oxaliplatin group has the least mass(P<0.01).Conclusions Paclitaxel plus oxaliplatin group chemotherapy significantly increases PDCD5 expression and reduce XIAP expression.Meanwhile, paclitaxel plus oxaliplatin chemotherapy can significantly reduce the tumor weight of happened non-small cell lung cancer.