Low programmed cell death 5 expression is a prognostic factor in ovarian cancer

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.

CircCERS6 Suppresses the Development of Epithelial Ovarian Cancer Through Mediating miR-630/RASSF8

Accumulating evidence have demonstrated that circular RNAs (circRNAs) exert important roles in tumor initiation and progression. Nevertheless, the role and mechanism of circRNA ceramide synthase 6 (circCERS6) in epithelial ovarian cancer (EOC) remain to be clarified. Using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot assay, we measured RNA and protein expression. We analyzed the effects of circCERS6/microRNA-630 (miR-630)/Ras-association domain family member 8 (RASSF8) axis in cell proliferation, migration, and invasion by 5-Ethynyl-2'-deoxyuridine (EdU) assay, colony formation assay, scratch test, and transwell assay. Using RNA-pull down assay and dual-luciferase reporter assay, the interaction between miR-630 and circCERS6 or RASSF8 was verified. The in vivo role of circCERS6 in tumor growth was analyzed using xenograft mice model. CircCERS6 expression was markedly reduced in EOC tissues and cell lines. CircCERS6 overexpression hampered the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of EOC cells. CircCERS6 directly interacted with miR-630. miR-630 expression was up-regulated in EOC tissues and cell lines. CircCERS6 overexpression-induced anti-tumor effects in EOC were largely reversed by the overexpression of miR-630. RASSF8 was a direct target of miR-630. RASSF8 level was decreased in EOC tissues and cell lines. CircCERS6 up-regulated RASSF8 expression by acting as a molecular sponge for miR-630 in EOC cells. CircCERS6 overexpression-mediated suppressive effects in EOC cells were largely overturned by the silence of RASSF8. CircCERS6 overexpression blocked tumor growth in vivo. CircCERS6 overexpression hampered the proliferation, migration, invasion, and EMT of EOC cells by up-regulating RASSF8 via sponging miR-630.

Research Progress in Prognostic Factors and Biomarkers of Ovarian Cancer

Ovarian cancer is a serious threat to women's health; its early diagnosis rate is low and prone to metastasis and recurrence. The current conventional treatment for ovarian cancer is a combination of platinum and paclitaxel chemotherapy based on surgery. The recurrence and progression of ovarian cancer with poor prognosis is a major challenge in treatment. With rapid advances in technology, understanding of the molecular pathways involved in ovarian cancer recurrence and progression has increased, biomarker-guided treatment options can greatly improve the prognosis of patients. This review systematically discusses and summarizes existing and new information on prognostic factors and biomarkers of ovarian cancer, which is expected to improve the clinical management of patients and lead to effective personalized treatment.

MicroRNA-320a Promotes Epithelial Ovarian Cancer Cell Proliferation and Invasion by Targeting RASSF8

MicroRNAs (miRNAs) play important roles in tumorigenesis by controlling target gene expression. With opposing roles as a tumor suppressor or oncogene, microRNA-320a (miR-320a) was found to participate in tumor genesis and progression and also identified as a potentially useful marker in cancer diagnosis, treatment, and prognosis. To better understand the role of miR-320a in ovarian cancer, we investigated miR-320a expression in epithelial ovarian cancer (EOC) specimens as well as EOC cell lines and analyzed correlations between miR-320a expression and processes associated with EOC progression. The miR-320a level in EOC specimens was found to be associated with ovarian cancer progression and infiltration. Through in vitro and in vivo studies, we found that miR-320a significantly promoted the proliferation, migration, and invasion of EOC cells, and we identified RASSF8 as a target gene of miR-320a that was downregulated in EOC tissues and cell lines. In vitro downregulation of RASSF8 promoted the growth, migration, and invasion of EOC cells. Together these findings indicate that RASSF8 is a direct target of miR-320a, through which miR-320a promotes the progression of EOC.

DPY30 is required for the enhanced proliferation, motility and epithelial-mesenchymal transition of epithelial ovarian cancer cells

Epithelial ovarian cancer (EOC) is one of the most lethal gynecological malignancies and is known to be associated with the accumulation of various genetic and epigenetic alterations. As a member of the human histone-lysine N-methyltransferase SETD1A (SET1)/histone-lysine N-methyltransferase 2A (MLL) complexes that are required for full SET1/MLL methyltransferase activity, protein dpy-30 homolog (DPY30) catalyzes histone H3K4 methylation, and its dysfunction has been associated with the occurrence of cancer. Therefore, the present study investigated the role of DPY30 in EOC and the potential association between DPY30 expression and the clinicopathological characteristics of EOC. The expression of DPY30 was examined in EOC tissues and cell lines to identify any correlations between the clinico-pathological characteristics of EOC and DPY30 expression, and to determine the effects of DPY30 on EOC cell proliferation, migration and invasion. DPY30 was highly expressed in EOC tissues and cell lines, and high DPY30 expression was significantly associated with notable clinicopathological variables in EOC patients, including International Federation of Gynecology and Obstetrics stage, pathological grade and lymph node metastasis. Functional studies on EOC cell lines demonstrated that DPY30 significantly promoted cell proliferation, migration, and invasion, accelerated cell cycle progression, and promoted epithelial-mesenchymal transition. Chromatin immunoprecipitation assay results revealed that DPY30 regulates histone H3K4 modification via interaction with the vimentin gene promoter, suggesting that DPY30 promotes the transcription of vimentin. Finally, high expression of DPY30 was significantly associated with reduced survival in patients with EOC. The results indicated that DPY30 may act as an oncogene in EOC and thus represents a potential therapeutic target and prognostic marker in EOC.

Association between circadian gene CLOCK and cisplatin resistance in ovarian cancer cells: A preliminary study

The present study aimed to observe the expression of circadian gene clock circadian regulator (CLOCK) in ovarian cancer cells and the effects of circadian gene CLOCK on cis-dichlorodiamine platinum (cisplatin) resistance in ovarian cancer cells. The expression of CLOCK mRNA and protein in cisplatin-sensitive A2780 and cisplatin-resistant CP70 cells were detected by quantitative polymerase chain reaction and western blot assay. Cisplatin-sensitive A2780 and cisplatin-resistant CP70 cells were treated with different concentrations of cisplatin for 48 h, and the expression of hCLOCK protein in the two types of cells was detected by western blot assay. RNA interference method was used to knock down the expression of CLOCK in cisplatin-resistant CP70 cells. Subsequently, the cisplatin-resistant CP70 cells were treated with cisplatin. The proliferation of cisplatin-resistant CP70 cells was observed following treatment with cisplatin. The expression of CLOCK mRNA was significantly higher in cisplatin-resistant CP70 cells (1.58±0.49) compared with cisplatin-sensitive A2780 cells (0.44±0.13) (P<0.01). Western blot assay results demonstrated that the expression of CLOCK protein was significantly greater in the cisplatin-resistant CP70 cells (1.47±0.34) compared with the cisplatin-sensitive A2780 cells (0.48±0.15) (P<0.01). Following the treatment of A2780 and CP70 cells with cisplatin, CLOCK protein expression increased with an increased concentration of cisplatin, in a dose-dependent manner (P<0.01). Following the knockdown of CLOCK in cisplatin-resistant CP70 cells by RNA interference, cisplatin treatment was able to significantly inhibit the proliferation of cells and induce apoptosis (P<0.01). The expression of circadian gene CLOCK in ovarian cancer cells was strongly associated with cisplatin resistance. The upregulation of circadian gene CLOCK in ovarian cancer cells may reduce its sensitivity to cisplatin treatment.

Genome-wide screening for genomic aberrations in Kazakh patients with esophageal squamous cell cancer by comparative genomic hybridization

Multiple chromosome aberrations are responsible for tumorigenesis of esophagus squamous cell carcinoma (ESCC). To characterize genetic alterations by comparative genomic hybridization (CGH) and their relation to ESCC, We enrolled 54 members with ESCC from Kazakh's patients. We found that the deletions of 3p (P = 0.032), 17p (P = 0.004), 22q (P = 0.000) and gains of 5p (P = 0.000), 11q (P = 0.000) were significantly correlated with the location of tumors. Losses of 1p (P = 0.005), 3p (P = 0.006), 22q (P = 0.024) and gains of 3q (P = 0.043), 8q (P = 0.038), 18q (P = 0.046) were also found more frequently in patients with larger diameter disease. The loss of 19q (P = 0.005) and gains of l3q (P = 0.045), 18p (P = 0.018) were significantly correlated with pathologic grade. The gain of 7p (P = 0.009) and deletion of 19q (P = 0.018) were seen more frequently in patients with Grade III-IV tumors. Chromosome amplifications in ESCC at 1q (P = 0.008), 7p (P = 0.008), 8q (P = 0.018) and deletions at 3p (P = 0.021), 11q (P = 0.002), 17p (P = 0.012) were related to lymph node metastasis; the gains of 1q (P = 0.026) and 6q (P = 0.017) and the loss of 11q (P = 0.001) were significant in different isoforms of HPV infection. We identified some chromosomes in which the genes were related to the tumorgenesis of ESCC, which may be a theme for future investigation.

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.

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

Endometrial cancer is one of the most common malignancies in the female genital tract. Programmed cell death 5 (PDCD5) is a newly identified apoptosis related gene and plays an important role in the development of some human tumors. However, the expression and clinical significance of PDCD5 in endometrial cancer have not been fully elucidated. Here, we evaluated the expression of PDCD5 in endometrioid endometrial carcinoma and control endometrium by qRT-PCR, western blot and immunohistochemistry, and analyzed the associations of PDCD5 expression with clinicopathological parameters of patients. In addition, we detected the expression of PDCD5 in control endometrial glandular epithelial cells and endometrioid endometrial carcinoma-derived cell line KLE by immunocytochemistry. The results showed that PDCD5 protein mainly expressed in the cytoplasm of glandular epithelial cells and endometrial carcinoma cells, and there was a low level of PDCD5 expression in the nuclei of the above cells. Furthermore, PDCD5 protein level was significantly lower in endometrial carcinoma samples than that in control endometrium. The decreased PDCD5 expression was correlated with the tumor differentiation degree. It is clear that PDCD5 protein expression was lower in middle and low differentiated endometrial carcinoma compared with control endometrium and high differentiated endometrial carcinoma. However, there were no significant differences of PDCD5 expression between the proliferative phase and the secretory phase of control endometrium, as well as between high differentiated endometrial carcinoma and controls. The results were verified in control glandular epithelial cells and KLE cells by immunocytochemistry. Therefore, PDCD5 may play a key role in the pathogenesis of endometrial cancer and may be a novel target for diagnosis and treatment of endometrial cancer.

Diagnostic investigations of DKK-1 and PDCD5 expression levels as independent prognostic markers of human chondrosarcoma

In this study, we investigated the expression levels of Dickkopf-1 (DKK-1) and programmed cell death 5 (PDCD5) by using quantitative real-time PCR and immunohistochemistry in patients with chondrosarcoma. The DKK-1 mRNA levels were significantly higher in chondrosarcoma when compared with the corresponding nontumor tissues (mean ± SD: 4.23 ± 1.54; 1.54 ± 0.87; P = 0.001). PDCD5 mRNA levels were remarkably deceased in tumor tissues when compared with corresponding nontumor tissues (mean ± SD: 1.94 ± 0.73; 5.42 ± 1.73; P = 0.001). The high and moderate DKK-1 expressions were observed for 60% of chondrosarcoma samples in comparison with 27.5% of corresponding nontumor tissues (P  =  0.001). Moreover, low expression of PDCD5 was found in 67.5% of the tumor tissues when compared with the nontumor tissues (32.5%; P = 0.002). The results of this study showed that high DKK-1 expression levels were strongly related to MSTS stage (P = 0.011) and the advancement of histological grade (P < 0.001). Furthermore, the PDCD5 expression levels were correlated with histological grade (P < 0.001), MSTS stage (P = 0.016), and distant metastasis (P = 0.001). Kaplan-Meier survival and log-rank survival showed that patients with high DKK-1 levels and low PDCD5 levels were correlated with shorter overall survival (log-rank test P < 0.001). PDCD5 levels, histological grade, and tumor stage were independent predictors of overall survival. In conclusion, DKK-1 and PDCD5 can be independent predictors of overall survival in patients suffering from chondrosarcoma. © 2016 IUBMB Life, 68(7):597-601, 2016.

Cyclin Y regulates the proliferation, migration, and invasion of ovarian cancer cells via Wnt signaling pathway

This study is designated to investigate the roles of cyclin Y (CCNY) and Wnt signaling pathway in regulating ovarian cancer (OC) cell proliferation, migration, and invasion. Quantitative real-time PCR (qRT-PCR), Western blot, MTT assay, cell scratch, and transwell test were used in our study, and transplanted tumor model was constructed on nude mice. C-Myc, cyclin D1, PFTK1, ki67, OGT, and β-catenin protein expressions in tumor tissues were detected. CCNY was significantly upregulated in OC cell lines and tissues (both P < 0.05); significant association was observed between CCNY expression and clinicopathological stage, lymph node metastasis (LNM) (P < 0.05); and the CCNY expression in stages III to IV was higher than that in stages I to II, and patients with LNM had higher CCNY expression when compared with those in patients without LNM (P < 0.05); expressions of c-Myc, cyclin D, PFTK1, ki67, and OGT were upregulated in OC tissues compared with ovarian benign tissues, suggesting that these expressions were significantly different between the two groups (P < 0.05); CCNY significantly exacerbated proliferation, migration, and invasion of A2780 cells; c-Myc and cyclin D1 protein expressions increased as the expression of CCNY increased (P < 0.001); β-catenin expressions in A2780 cells with over-expression of CCNY were significantly increased in the nucleus, but significantly decreased in the cytoplasm (both P < 0.05); high expressions of CCNY exacerbated the proliferation of A2780 cells in nude mice and significantly increased c-Myc, cyclin D1, PFTK1, ki67, and OGT protein expressions in tumor tissues which were transplanted into nude mice (P < 0.01). CCNY might exacerbate the proliferation, migration, and invasion of OC cells via activating the Wnt signaling pathway. Thus, this study provides a theoretical foundation for the development of therapeutic drugs that are able to cure OC by targeting CCNY.

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.