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Haiyan Li,
Xia Zhang,
Xingguo Song,
Faliang Zhu,
Qun Wang,
Chun Guo, Chunmei Liu,
Yongyu Shi,
Chunhong Ma,
Xiaoyan Wang,
Lining Zhang
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ABSTRACT: Glioma is one of the most common primary brain tumors. Despite surgical resection, radiotherapy, and chemotherapy, the prognosis of patients with malignant glioma remains poor. Programmed cell death 5 (PDCD5) is a newly described pro-apoptotic protein. Our previous study showed that PDCD5 downregulation in gliomas was associated with higher pathological grade. Here, we investigated the effect of PDCD5 on chemosensitivity of glioma cells and its mechanism. We demonstrated that overexpression or knockdown of PDCD5 had no significant effect on the proliferation of glioma cell lines (U87, U251, and T98G) in the absence of chemotherapeutic agents. However, PDCD5 overexpression effectively sensitized U87 cells to chemotherapeutic drugs (cisplatin, carboplatin, and vincristine) in a concentration-dependent manner, while its knockdown resulted in decreased chemosensitivity in U251, T98G, and U87 cells. Importantly, expression of PDCD5 also markedly inhibited tumor cell proliferation and colony formation in the presence of low doses of cisplatin. Furthermore, we found that PDCD5 expression promoted cisplatin-induced apoptosis, increased markedly the activation of caspase-3 and caspase-9, and decreased significantly the ratio of Bcl-2/Bax proteins, but had no effect on the activation of caspase-8. Taken together, our findings indicate that PDCD5 promotes chemosensitivity by activating mitochondria-related apoptotic pathway, and that the combination of PDCD5 and chemotherapeutic drugs such as cisplatin, is expected to be an effective therapeutic strategy for the malignant glioma.
Cancer biology & therapy 07/2012; 13(9):822-30. · 2.64 Impact Factor
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ABSTRACT: Chemoresistance is a major cause of treatment failure in ovarian cancer. Therefore, it is necessary to explore alternative therapeutic methods to overcome drug resistance for ovarian cancer treatment. We previously reported that programmed cell death 4 (PDCD4), a tumor suppressor, significantly suppresses the malignant phenotype of ovarian cancer cells and its lost or low expression in ovarian cancer is associated with unfavorable prognosis of patients. Here we show that PDCD4 improves the sensitivity of ovarian cancer cells to platinum-based chemotherapy. Overexpression of PDCD4 enhanced chemosensitivity in SKOV3 and CAOV3 cells with low levels of PDCD4, whereas knockdown of PDCD4 reduced chemosensitivity in OVCAR3 cells with high levels of PDCD4. Subsequently, the combination of enforced PDCD4 expression with cisplatin treatment significantly suppressed ovarian tumor growth in a xenograft animal model. The PDCD4 effect appears to be specific for cisplatin and carboplatin, not affecting cyclophosphamide, etoposide, or paclitaxel. Mechanistically, PDCD4 significantly increased cisplatin-induced cleavage of caspase-3 and caspase-8, but had only a slight impact on caspase-9 cleavage and the expression of Bax and Bcl-2 in vitro and in vivo. A specific caspase-8 inhibitor, Z-ITED-FMK, attenuated cisplatin-induced apoptosis in PDCD4-overexpressing ovarian cancer cells. Taken together, our results indicate that PDCD4 enhances cisplatin-induced apoptosis by mainly activating the death receptor pathway, and PDCD4 gene transfer in combination with cisplatin therapy may break the resistance of ovarian cancer cells to chemotherapy.
Cancer Science 10/2010; 101(10):2163-70. · 3.33 Impact Factor
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Qun Wang, Chunmei Liu,
Faliang Zhu,
Fengming Liu,
Pin Zhang,
Chun Guo,
Xiaoyan Wang,
Haiyan Li,
Chunhong Ma,
Wensheng Sun,
Yun Zhang,
Wanjun Chen,
Lining Zhang
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ABSTRACT: Dendritic cells (DCs) are often exposed to various oxygen tensions under physiological and pathological conditions. However, the effects of various oxygen tensions on DC functions remain unclear. In this study, we showed that hypoxia-differentiated DCs expressed lower levels of MHC-II molecule, co-stimulatory molecules (CD80, CD86) and proinflammatory cytokines (IL-1beta, IL-6, and TNF-alpha), but higher levels of immunoregulatory cytokine transforming growth factor-beta (TGF-beta) than normoxia-differentiated DCs. Unexpectedly, re-exposure of hypoxia-differentiated DCs to saturated oxygen (reoxygenation) completely restored their mature phenotype and function. Specifically, the reoxygenated DCs induced naïve CD4(+) T cells to differentiate into Th1 and Th17 effector cells, but deceased the generation of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs). The data indicate that hypoxic microenvironment suppresses the maturation and function of murine DCs. Reoxygenation of hypoxia-differentiated DCs however results in complete recovery of their mature phenotype and function, and has strong ability to drive immune response toward a proinflammatory direction, suggesting reoxygenated DCs may contribute to inflammation of ischemia-reperfusion injury.
Molecular Immunology 11/2009; 47(4):922-31. · 2.90 Impact Factor
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Haiyan Li,
Qun Wang,
Fei Gao,
Faliang Zhu,
Xiaoyan Wang,
Chengjun Zhou, Chunmei Liu,
Yingyu Chen,
Chunhong Ma,
Wensheng Sun,
Lining Zhang
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ABSTRACT: Programmed cell death 5 (PDCD5) is a novel apoptosis-promoting protein. Recently, a decreased expression of PDCD5 has been found in several types of human tumors. However, the expression level of PDCD5 in human gliomas has not been investigated. In the present study, we examined the expression of PDCD5 in 88 human glioma samples at both mRNA and protein levels by RT-PCR, Western blotting and immunohistochemistry. We found that 53.3% (16/30) of the glioma samples had a reduced expression of PDCD5 mRNA and 70.5% (62/88) had a reduced expression of the PDCD5 protein as compared to normal brain tissue. Furthermore, we studied the correlation of the expression level of PDCD5 with the clinicopathological grade and survival of patients with astrocytomas. Although longitudinal studies of a cohort of patients with astrocytoma revealed that PDCD5 expression was not able to predict clinical outcome (p>0.05), a decreased expression of PDCD5 correlated significantly with high-grade astrocytomas (p<0.001). In conclusion, our data suggest that reduced PDCD5 expression may contribute to the pathogenesis of human gliomas.
Oncology Reports 09/2008; 20(3):573-9. · 1.84 Impact Factor
