Expression of programmed cell death 5 protein inhibits progression of lung carcinoma in vitro and in vivo via the mitochondrial apoptotic pathway

PDCD5 inhibits progression of renal cell carcinoma by promoting T cell immunity: with the involvement of the HDAC3/microRNA-195-5p/SGK1

BACKGROUND

Epigenetics exerts a vital role in the onset and development of renal cell carcinoma (RCC). Mounting evidence has shed light on the significance of human immune system in response to tumor infiltrating T cells. Hereby, we sought to unmask the immunomodulatory role of histone deacetylase 3 (HDAC3) and its potential upstream molecule, programmed cell death 5 (PDCD5) in RCC.

METHODS

RCC and adjacent non-cancerous tissues were clinically resected from 58 patients, in which the expression profile of microRNA-195-5p (miR-195-5p), PDCD5, HDAC3, and serum glucocorticoid-inducible kinase 1 (SGK1) was determined by RT-qPCR and Western blot analysis. Their relations were investigated by a series of luciferase assays in combination with ChIP and co-IP. RCC cells (A498) were intervened using gain- and loss-of-function approaches, followed by cell proliferation evaluation. After co-culture with CD3⁺ T cells, flow cytometry and interferon-γ (IFN-γ) determination were performed. A xenograft tumor mouse model was developed for in vivo validation.

RESULTS

PDCD5 was downregulated in RCC tissues and A498 cells. Upregulation of HDAC3, as well as of SGK1, resulted in suppression of A498 cell proliferation and promotion of T cell activation as evidenced by higher IFN-γ expression. Re-expression of PDCD5 downregulated HDAC3, causing a subsequent upregulation of miR-195-5p, while miR-195-5p could inversely modulate its target gene, SGK1. The regulatory mechanism appeared to be functional in vivo.

CONCLUSION

Our results highlight the possible manipulation by PDCD5 on RCC cell proliferation and T cell activation, which provides new clues to better understand the immune balance in RCC progression.

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.

Esculetin induces apoptosis of SMMC-7721 cells through IGF-1/PI3K/Akt-mediated mitochondrial pathways

Esculetin (6,7-dihydroxycoumarin) is a coumarin derivative extracted from natural plants and has been reported to have anticancer activity. However, the mechanism by which esculetin prevents human hepatic cancer cell growth is still largely unknown. In this study, we investigated the effect of esculetin on human hepatocellular carcinoma (HCC) SMMC-7721 cells and explored the cell signal mechanism. Our data indicated that esculetin induced apoptosis in SMMC-7721 cells, which were supported by DAPI staining and Annexin V/PI staining. Meanwhile, esculetin increased the activities of caspase-3 and caspase-9, promoted bax expression, decreased bcl-2 expression, and triggered collapse of mitochondrial membrane potential, and increased cytochrome c release from mitochondria. In addition, the inactivation of IGF-1, PI3K, and Akt was observed after esculetin administration. Furthermore, pretreatment with IGF-1 before esculetin administration abrogated the pro-apoptotic effects of esculetin, while PI3K inhibitor increased the pro-apoptotic effects of esculetin. These results indicated that esculetin induced the apoptosis of SMMC-7721 cells through IGF-1/PI3K/Akt-regulated mitochondrial dysfunction.

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.

Cellular functions of programmed cell death 5

Programmed cell death 5 (PDCD5) was originally identified as an apoptosis-accelerating protein that is widely expressed and has been well conserved during the process of evolution. PDCD5 has complex biological functions, including programmed cell death and immune regulation. It can accelerate apoptosis in different type of cells in response to different stimuli. During this process, PDCD5 rapidly translocates from the cytoplasm to the nucleus. PDCD5 regulates the activities of TIP60, HDAC3, MDM2 and TP53 transcription factors. These proteins form part of a signaling network that is disrupted in most, if not all, cancer cells. Recent evidence suggests that PDCD5 participates in immune regulation by promoting regulatory T cell function via the PDCD5-TIP60-FOXP3 pathway. The stability and expression of PDCD5 are finely regulated by other molecules, such as NF-κB p65, OTUD5, YAF2 and DNAJB1. PDCD5 is phosphorylated by CK2 at Ser119, which is required for nuclear translocation in response to genotoxic stress. In this review, we describe what is known about PDCD5 and its cellular functions.