Tumour-suppressive microRNA-424-5p directly targets CCNE1 as potential prognostic markers in epithelial ovarian cancer

An accumulated evidence supports that MicroRNAs (miRNAs) have shown a prominent role in pathological processes and different tumor onset. However, to date, the potential functional roles and molecular mechanisms by how microRNA-424-5p(miR-424-5p) affects cancer cell proliferation are greatly unclear, especially in epithelial ovarian cancer(EOC).In this study, we demonstrated that miR-424-5p was significantly down-regulated in EOC tissues and cell lines. The level of miR-424-5p was negatively correlated with tumor size, TNM stage, pathological grade, lymphatic metastasis of EOC. Restoring miR-424-5p expression in EOC cells dramatically suppressed cell proliferation and caused an accumulation of cells in G1 phase, and thus contributed to better prognosis of EOC patients. Mechanistically, miR-424-5p inhibits CCNE1 expression through targeting CCNE1 3′UTR, and subsequent arrest cell cycle in G1/G0 phase by inhibiting E2F1-pRb pathway. This study revealed functional and mechanistic links between miR-424-5p and CCNE1 in the progression of EOC and provide an important insight into that miR-424-5p may serve as a therapeutic target in EOC.     

Roles of metformin-mediated girdin expression in metastasis of epithelial ovarian cancer

Antimetastatic effect of Metformin has been documented in epithelial ovarian cancer (EOC). Presently, we investigated the regulatory mechanism of Metformin in EOC metastasis. First, Girdin was significantly enhanced in EOC tumorous tissues and cell lines. Seconded, knockdown of Girdin significantly suppressed EOC cell viability, migration, and invasion, while upregulation of Girdin produced the opposite effects in vitro and facilitated lung metastasis in EOC cell xenograft in vivo. In addition, we confirmed that the inhibitory effect of Metformin on Girdin expression. Mechanistically, the oncogenic effects of Girdin could be reversed by LY294002 (an AKT pathway inhibitor) and Metformin. These results suggested that Metformin attenuated EOC metastasis through Girdin and targeting Girdin may be a promising therapeutic strategy for EOC in the future.     

Wee1 kinase as a target for cancer therapy

Wee1, a protein kinase, regulates the G₂ checkpoint in response to DNA damage. Preclinical studies have elucidated the role of wee1 in DNA damage repair and the stabilization of replication forks, supporting the validity of wee1 inhibition as a viable therapeutic target in cancer. MK-1775, a selective and potent small-molecule inhibitor of wee1, is under clinical development as a potentiator of DNA damage caused by cytotoxic chemotherapies. We present a review of the role of wee1 in the cell cycle and DNA replication and summarize the clinical development to date of this novel class of anticancer agents.     

Protein kinase ATR inhibits E3 ubiquitin ligase CRL4PRL1 to stabilize ribonucleotide reductase in response to replication stress

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Detection of exosomal tyrosine receptor kinase B as a potential biomarker in ovarian cancer

Ovarian cancer (OC) is a lethal disease diagnosed at advanced stages due to the lack of specific biomarkers. Tyrosine receptor kinase B (TrkB), which has recently been found to be related to OC progression, represents a promising potential biomarker for OC diagnosis and prognosis. The discovery of circulating exosomes as biomarkers for various diseases led us to explore exosomal TrkB in OC. Our previous study proved that the expression of TrkB was elevated in OC tissues. In this study, we focused on the detection of exosomal TrkB in OC. Exosomes were first gathered from three different OC cell lines’ conditioned medium, serum samples of patients with OC as well as xenograft mice serum by serial centrifugation method. Then, we identified exosomes by transmission electron microscopy, NanoSight analysis, and expression of typical exosomal protein markers. The existence of TrkB in exosomes was measured by Western blot analysis, and the expression was detected by enzyme-linked immunosorbent assay. In this study, we demonstrated that exosomes could derive from OC cell lines, serum from OC xenograft nude mice, and clinical patients. Our study shows that serum exosomal TrkB may be considered a minimally invasive biomarker for OC.     

Snake venoms promote stress-induced senescence in human fibroblasts

Snake venoms are widely studied in terms of their systemic toxicity and proteolytic, hemotoxic, neurotoxic, and cytotoxic activities. However, little is known about snake-venom-mediated effects when used at low, noncytotoxic concentrations. In the current study, two human fibroblast cell lines of different origin, namely WI-38 fetal lung fibroblasts and BJ foreskin fibroblasts were used to investigate snake-venom-induced adaptive response at a relatively noncytotoxic concentration (0.01 µg/ml). The venoms of Indochinese spitting cobra ( Naja siamensis), western green mamba ( Dendroaspis viridis), forest cobra ( Naja melanoleuca), and southern copperhead ( Agkistrodon contortrix) were considered. Snake venoms promoted FOXO3a-mediated oxidative stress response and to a lesser extent DNA damage response, which lead to changes in cell cycle regulators both at messenger RNA and protein levels, limited cell proliferation and migration, and induced cellular senescence. Taken together, we have shown for the first time that selected snake venoms may also exert adverse effects when used at relatively noncytotoxic concentrations.     

Eph receptor A10 has a potential as a target for a prostate cancer therapy

We recently identified Eph receptor A10 (EphA10) as a novel breast cancer-specific protein. Moreover, we also showed that an in-house developed anti-EphA10 monoclonal antibody (mAb) significantly inhibited proliferation of breast cancer cells, suggesting EphA10 as a promising target for breast cancer therapy. However, the only other known report for EphA10 was its expression in the testis at the mRNA level. Therefore, the potency of EphA10 as a drug target against cancers other than the breast is not known. The expression of EphA10 in a wide variety of cancer cells was studied and the potential of EphA10 as a drug target was evaluated. Screening of EphA10 mRNA expression showed that EphA10 was overexpressed in breast cancer cell lines as well as in prostate and colon cancer cell lines. Thus, we focused on prostate cancers in which EphA10 expression was equivalent to that in breast cancers. As a result, EphA10 expression was clearly shown in clinical prostate tumor tissues as well as in cell lines at the mRNA and protein levels. In order to evaluate the potential of EphA10 as a drug target, we analyzed complement-dependent cytotoxicity effects of anti-EphA10 mAb and found that significant cytotoxicity was mediated by the expression of EphA10. Therefore, the idea was conceived that the overexpression of EphA10 in prostate cancers might have a potential as a target for prostate cancer therapy, and formed the basis for the studies reported here.     

Identification of a small molecule SR9009 that activates NRF2 to counteract cellular senescence

The senescence‐associated secretory phenotype (SASP) is a striking characteristic of senescence. Accumulation of SASP factors causes a pro‐inflammatory response linked to chronic disease. Suppressing senescence and SASP represents a strategy to prevent or control senescence‐associated diseases. Here, we identified a small molecule SR9009 as a potent SASP suppressor in therapy‐induced senescence (TIS) and oncogene‐induced senescence (OIS). The mechanism studies revealed that SR9009 inhibits the SASP and full DNA damage response (DDR) activation through the activation of the NRF2 pathway, thereby decreasing the ROS level by regulating the expression of antioxidant enzymes. We further identified that SR9009 effectively prevents cellular senescence and suppresses the SASP in the livers of both radiation‐induced and oncogene‐induced senescence mouse models, leading to alleviation of immune cell infiltration. Taken together, our findings suggested that SR9009 prevents cellular senescence via the NRF2 pathway in vitro and in vivo, and activation of NRF2 may be a novel therapeutic strategy for preventing cellular senescence.     

Immunomodulatory action of the DNA methyltransferase inhibitor SGI-110 in epithelial ovarian cancer cells and xenografts

We aimed to determine the effect of SGI-110 on methylation and expression of the cancer testis antigens (CTAs) NY-ESO-1 and MAGE-A in epithelial ovarian cancer (EOC) cells in vitro and in vivo and to establish the impact of SGI-110 on expression of major histocompatibility (MHC) class I and Intracellular Adhesion Molecule 1 (ICAM-1) on EOC cells, and on recognition of EOC cells by NY-ESO-1-specific CD8+ T-cells. We also tested the impact of combined SGI-110 and NY-ESO-1-specific CD8+ T-cells on tumor growth and/or murine survival in a xenograft setting. EOC cells were treated with SGI-110 in vitro at various concentrations and as tumor xenografts with 3 distinct dose schedules. Effects on global methylation (using LINE-1), NY-ESO-1 and MAGE-A methylation, mRNA, and protein expression were determined and compared to controls. SGI-110 treated EOC cells were evaluated for expression of immune-modulatory genes using flow cytometry, and were co-cultured with NY-ESO-1 specific T-cell clones to determine immune recognition. In vivo administration of SGI-110 and CD8+ T-cells was performed to determine anti-tumor effects on EOC xenografts. SGI-110 treatment induced hypomethylation and CTA gene expression in a dose dependent manner both in vitro and in vivo, at levels generally superior to azacitidine or decitabine. SGI-110 enhanced the expression of MHC I and ICAM-1, and enhanced recognition of EOC cells by NY-ESO-1-specific CD8+ T-cells. Sequential SGI-110 and antigen-specific CD8+ cell treatment restricted EOC tumor growth and enhanced survival in a xenograft setting. SGI-110 is an effective hypomethylating agent and immune modulator and, thus, an attractive candidate for combination with CTA-directed vaccines in EOC.     

miR-214-mediated downregulation of RNF8 induces chromosomal instability in ovarian cancer cells

Defective DNA damage response (DDR) is frequently associated with carcinogenesis. Abrogation of DDR leads to chromosomal instability, a most common characteristic of tumors. However, the molecular mechanisms underlying regulation of DDR are still elusive. The ubiquitin ligase RNF8 mediates the ubiquitination of γH2AX and recruits 53BP1 and BRCA1 to DNA damage sites which promotes DDR and inhibits chromosomal instability. Though RNF8 is a key player involved in DDR, regulation of its expression is still poorly understood. Here, we show that miR-214 could abrogate DDR by repressing RNF8 expression through direct binding to 3′-untranslated region (3′ UTR) of RNF8 mRNA in human ovarian cancer cells. Antagonizing miR-214 by expressing its inhibitors in A2780 cells significantly increased RNF8 expression and thus promoted DNA damage repair. Consistent with the role of miR-214 in regulating RNF8 expression, the impaired DNA repair induced by miR-214 overexpression can be rescued by overexpressing RNF8 mRNA lacking the 3′ UTR. Together, our results indicate that down-regulation of RNF8 mediated by miR-214 impedes DNA damage response to induce chromosomal instability in ovarian cancers, which may facilitate the understanding of mechanisms underlying chromosomal instability.     

Long noncoding RNA WDFY3-AS2 suppresses tumor progression by acting as a competing endogenous RNA of microRNA-18a in ovarian cancer

Ovarian cancer (OC) is a fatal cancer in women, mainly due to its aggressive nature and poor survival rate. The lncRNA-miRNA-mRNA (long noncoding RNA-microRNA-messenger RNA) interaction is promising biomarkers for the improving prognosis of OC. Therefore, we explored the regulatory mechanism of WDFY3-AS2/miR-18a/RORA axis involved in the biological activities of OC cells. Microarray analysis predicted differentially expressed lncRNA, miRNA, and mRNA related to OC, followed by investigating the relationship among them. The expression patterns of the identified lncRNA WDFY3-AS2, miR-18a, and RORA were measured in OC tissue and cells. Gain- and loss-of-function experiments were performed to characterize the effect of lncRNA WDFY3-AS2 on OC cells, as well as the involvement of miR-18a and RAR related orphan receptor A (RORA). The in vitro assays were validated by in vivo experiments. According to bioinformatics analysis, WDFY3-AS2 was speculated to affect OC by sponging miR-18a and modulating RORA. WDFY3-AS2 and RORA were underexpressed in OC, while miR-18a was highly expressed. Notably, WDFY3-AS2 acts as a competing endogenous RNA to sponge miR-18a and upregulate RORA. Upon overexpressing WDFY3-AS2 or inhibiting miR-18a, RORA expression was increased, thereby the OC cell proliferation, migration, invasion, and epithelial-to-mesenchymal transition (EMT) were suppressed, accompanied by enhanced apoptosis. In vivo experiments confirmed that the tumor growth was reduced in response to overexpressed WDFY3-AS2 or inhibited miR-18a. Taken together, the lncRNA WDFY3-AS2/miR-18a axis regulates the tumor progression of OC by targeting RORA, providing new insights for prevention and control of OC.     

Peritoneal M2 macrophage transplantation as a potential cell therapy for enhancing renal repair in acute kidney injury

Acute kidney injury (AKI) is a clinical condition that is associated with high morbidity and mortality. Inflammation is reported to play a key role in AKI. Although the M2 macrophages exhibit antimicrobial and anti-inflammatory activities, their therapeutic potential has not been evaluated for AKI. This study aimed to investigate the protective effect of peritoneal M2 macrophage transplantation on AKI in mice. The macrophages were isolated from peritoneal dialysates of mice. The macrophages were induced to undergo M2 polarization using interleukin (IL)-4/IL-13. AKI was induced in mice by restoring the blood supply after bilateral renal artery occlusion for 30 minutes. The macrophages were injected into the renal cortex of mice. The changes in renal function, inflammation and tubular proliferation were measured. The M2 macrophages were co-cultured with the mouse primary proximal tubular epithelial cells (PTECs) under hypoxia/reoxygenation conditions in vitro. The PTEC apoptosis and proliferation were analysed. The peritoneal M2 macrophages effectively alleviated the renal injury and inflammatory response in mice with ischaemia-reperfusion injury (IRI) and promoted the PTEC proliferation in vivo and in vitro. These results indicated that the peritoneal M2 macrophages ameliorated AKI by decreasing inflammatory response and promoting PTEC proliferation. Hence, the peritoneal M2 macrophage transplantation can serve as a potential cell therapy for renal diseases.     

Protein kinase D as a potential new target for cancer therapy

Protein kinase D is a novel family of serine/threonine kinases and diacylglycerol receptors that belongs to the calcium/calmodulin-dependent kinase superfamily. Evidence has established that specific PKD isoforms are dysregulated in several cancer types, and PKD involvement has been documented in a variety of cellular processes important to cancer development, including cell growth, apoptosis, motility, and angiogenesis. In light of this, there has been a recent surge in the development of novel chemical inhibitors of PKD. This review focuses on the potential of PKD as a chemotherapeutic target in cancer treatment and highlights important recent advances in the development of PKD inhibitors.