The reduced PDCD5 protein is correlated with the degree of tumor differentiation in endometrioid endometrial carcinoma

PDCD5 inhibits osteosarcoma cell metastasis via targeting TGF-β1/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-β1/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-β1 (TGF-β1) in a time-dependent manner, and TGF-β1-induced EMT was induced by PDCD5 knockdown. Inactivation of the TGF-β1/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-β1/Smad signaling pathway to inhibit OS metastasis and may be a potential adjuvant genetic therapy for OS.

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.

Roles of programmed cell death protein 5 in inflammation and cancer (Review)

PDCD5 (programmed cell death 5) is an apoptosis related gene cloned in 1999 from a human leukemic cell line. PDCD5 protein containing 125 amino acid (aa) residues sharing significant homology to the corresponding proteins of species. Decreased expression of PDCD5 has been found in many human tumors, including breast, gastric cancer, astrocytic glioma, chronic myelogenous leukemia and hepatocellular carcinoma. In recent years, increased number of studies have shown the functions and mechanisms of PDCD5 protein in cancer cells, such as paraptosis, cell cycle and immunoregulation. In the present review, we provide a comprehensive review on the role of PDCD5 in cancer tissues and cells. This review summarizes the recent studies of the roles of PDCD5 in inflammation and cancer. We mainly focus on discoveries related to molecular mechanisms of PDCD5 protein. We also discuss some discrepancies between the current studies. Overall, the current available data will open new perspectives for a better understanding of PDCD5 in cancer.