Dual roles of BK Polyomavirus in promoting urothelial carcinoma progression via regulating CLDN1.

Uncontrolled productive infection of BK polyomaviruses (BKV) in immunocompromised patients was reported to result in serious diseases, especially renourinary malignancies. However, the mechanism of BKV as a role of human carcinogen is still unknown. In this study, we showed that there is a significant association between BKV infection and metastasis of urothelial carcinoma (UCA). BKV-infected tumor tissues exhibit invasive histologic phenomena with vascular invasion and myometrial invasion. Then we identified that BKV promotes UCA invasion in a mode of dual regulation of tumor cells (TCs) invasion and endothelial cells (ECs) adhesion by encoding miRNAs. In cancer cells, BKV-B1-miR-5p promotes cell motility and invasiveness by directly targeting CLDN1. Moreover, exosomal-BKV-B1-miR-3p derived from BK-infected BC cells would be transferred to ECs and increase its adhesion to tumor cells by switching on the CLDN1 enhancer, which subsequently destroyed endothelial monolayers and increased permeability. In a human urothelial cancer metastasis mouse model, BK-inoculated cells exhibited higher incidence of vascular leakage and liver colonization. However, the vascular leakage and liver metastasis could be reduced when knocking down miRNAs in BK-inoculated cells. Our research delineates the bifunctional impact of BKV-encoded microRNAs on the expression of CLDN1 within both TCs and ECs, which orchestrates the establishment of a pre-metastatic niche in UCA.

Phenotypic and genetic characterization of hypervirulent Klebsiella pneumoniae in patients with liver abscess and ventilator-associated pneumonia.

Ventilator-associated pneumonia (VAP) and pyogenic liver abscess (PLA) due to Klebsiella pneumoniae infection can trigger life-threatening malignant consequences, however, there are few studies on the strain-associated clinical pathogenic mechanisms between VAP and PLA. A total of 266 patients consist of 129 VAP and 137 PLA were included for analysis in this study. We conducted a comprehensive survey for the two groups of K. pneumoniae isolates, including phenotypic experiments, clinical epidemiology, genomic analysis, and instrumental analysis, i.e., to obtain the genomic differential profile of K. pneumoniae strains responsible for two distinct infection outcomes. We found that PLA group had a propensity for specific underlying diseases, especially diabetes and cholelithiasis. The resistance level of VAP was significantly higher than that of PLA (78.57% vs. 36%, P < 0.001), while the virulence results were opposite. There were also some differences in key signaling pathways of biochemical processes between the two groups. The combination of iucA, rmpA, hypermucoviscous phenotype, and ST23 presented in K. pneumoniae infection is more important and highly prudent for timely treatment. The present study may contribute a benchmark for the K. pneumoniae clinical screening, epidemiological surveillance, and effective therapeutic strategies.

Intracellular Low Iron Exerts Anti-BK Polyomavirus Effect by Inhibiting the Protein Synthesis of Exogenous Genes.

BK polyomavirus (BKPyV) is a small double-stranded DNA virus and ubiquitous human pathogen that particularly affects immunocompromised individuals. Antiviral therapy for BKPyV is urgently needed. Intracellular irons have an important role in many viral infections, yet its contribution to BKPyV and replication has not been explored. In this study, we explored the interaction between BKPyV infection and intracellular iron and the inhibitory effect of iron depletion on BKPyV infection. By creating a low-intracellular-iron environment, we demonstrated that the iron-chelating-induced iron depletion inhibits BKPyV infection in primary renal tubular epithelial cells (RPTECs) and urinary bladder cancer cells (TCCSUP cells). Iron depletion exerts an inhibitory effect after BKPyV enters the nucleus, which might be due to the inhibition of the protein synthesis of exogenous genes in iron-depleted cells. Further exploration of the target proteins of iron-regulating viral infection could potentially be used to develop new strategies for urgently needed anti-BKPyV therapies. IMPORTANCE BKPyV poses a serious threat to the health of immunocompromised patients, and there are currently no curative drugs. Understanding the relationship between the virus and intracellular environment contributes to the discovery of antiviral targets. We demonstrate here that BKPyV is inhibited in cells with a low-iron environment. We also find that iron-chelating-induced iron depletion inhibits viral and exogenous protein synthesis. Further exploration of the target proteins of iron regulation could have great potential in developing new drugs against BKPyV and other viruses.

BK polyomavirus infection promotes growth and aggressiveness in bladder cancer.

BACKGROUND: Recent studies have confirmed the integration of the BK polyomavirus (BKPyV) gene into the cellular genome of urothelial carcinomas in transplant recipients, further confirming the correlation between BKPyV and urothelial carcinomas after transplantation. However, the role BKPyV infections play in the biological function of bladder cancer remains unclear. METHODS: We developed a BKPyV-infected bladder cancer cell model and a mice tumor model to discuss the role of BKPyV infections. RESULTS: Our research proves that BKPyV infections promote the proliferation, invasion and migration of bladder cancer cells, while the activation of ß-catenin signaling pathway is one of its mediation mechanisms. CONCLUSIONS: We first described BKPyV infection promotes the proliferation, invasion and migration of bladder cancer. We verified the role of ß-catenin signaling pathway and Epithelial-Mesenchymal Transition effect in BKPyV-infected bladder cancer. These results provide meaningful information towards the diagnosis and treatment of clinical bladder cancer.

High-mobility group box 1 protein antagonizes the immunosuppressive capacity and therapeutic effect of mesenchymal stem cells in acute kidney injury.

BACKGROUND: Kidney ischemia reperfusion injury (IRI) is a common cause of acute kidney injury and an unavoidable consequence of kidney transplantation and still lacks specific therapeutics. Recently, mesenchymal stem cell (MSC) has been emerging as a promising cell-based therapy for IRI in the context of transplantation. MSC negatively regulates the secretion of pro-inflammatory as well as the activation of immune cells during IRI through its unique immunosuppressive property. METHODS: We employed mice kidney IRI model and MSC cell line to monitor the IRI related checkpoints. siRNAs were utilized to knock down the potential key factors for mechanistic analysis. Statistical analysis was performed by using one-way ANOVA with Tukey's post hoc procedure by SPSS. RESULTS: The expression of high-mobility group box 1 protein (HMGB1) is increased in the acute phase as well as the recovery stage of IRI. Importantly, the HMGB1 upregulation is correlated with the injury severity. HMGB1 diminishes the MSC induced immunosuppressive capacity in the presence of pro-inflammatory cytokines in vitro. Toll like receptor 4 (TLR4)-mediated inducible nitric oxide synthase (iNOS) inhibition contributes to the negative effect of HMGB1 on MSCs. HMGB1-TLR4 signaling inhibition augments the therapeutic efficacy of MSCs in mice renal IRI model. CONCLUSIONS: These findings demonstrate that HMGB1 plays a crucial role in shaping the immunoregulatory property of MSCs within the microenvironments, providing novel insights into the crosstalk between MSCs and microenvironment components, suggesting HMGB1 signals as a promising target to improve MSC-based therapy.

Mast cell infiltration associated with loss of interstitial cells of Cajal and neuronal degeneration in achalasia.

BACKGROUND: Achalasia is a motility disorder of unknown etiology. Previous studies supported the hypothesis that autoimmune-mediated inflammatory responses produce inhibitory neuronal degeneration. This study was designed to explore the role of mast cells in achalasia. METHODS: We collected information from 116 patients with achalasia who underwent peroral endoscopic myotomy between December 2016 and May 2017. Lower esophageal sphincter (LES) muscle biopsy was performed in all patients with achalasia, as well as 20 control subjects. The number of mast cells, interstitial cells of Cajal (ICCs), nNOS-positive cells, and S-100-positive cells in the LES were evaluated by immunohistochemistry. Pathological and clinical data were compared between groups. KEY RESULTS: Compared with controls, the LES of patients with achalasia had significantly fewer ICCs, nNOS-positive cells, and S-100-positive cells and a higher number of mast cells (all P < 0.001). Furthermore, the increased mast cell infiltration was significantly associated with decreased ICCs, nNOS-positive cells, and S-100-positive cells in patients with achalasia (all P < 0.05). Clinically, the number of strongly positive mast cells was highest in patients with type I achalasia and lowest in those with type III achalasia (P < 0.001). In addition, patients with a history of autoimmune disease or viral infection had greater mast cell infiltration in the LES muscle (P = 0.040). CONCLUSIONS & INFERENCES: In patients with achalasia, mast cell infiltration in the LES muscle is increased, in association with loss of ICCs and neuronal degeneration. Mast cells may thereby play a crucial role in the development of achalasia.

Differential microRNA expression in aristolochic acid-induced upper urothelial tract cancers ex vivo.

Aristolochic acid (AA) is a carcinogenic, mutagenic and nephrotoxic compound commonly isolated from members of the plant family of Aristolochiaceae (such as Aristolochia and Asarum) and used in Chinese herbal medicine. Use of AA and AA­containing plants causes chronic kidney disease (CKD) and upper urinary tract carcinoma (UUC); however, the underlying mechanism remains to be defined. miRNAs regulate a number of biological processes, including cell proliferation, differentiation and metabolism. This study explored differentially expressed miRNAs between AA­induced upper urothelial tract cancer (AAN­UUC) and non­AAN­UUC tissues. Patients with AAN­UUC and non­AAN­UUC (n=20/group) were recruited in the present study. Five tissue samples from each group were used for miRNA microarray profiling and the rest of the tissue samples were subjected to reverse transcription-quantitative polymerase chain reaction analysis including seven selected miRNAs for confirmation. A total of 29 miRNAs were differentially expressed between AAN­UUC and non­AAN­UUC tissues (P<0.05). TargenScan and Gene ontology analyses predicted the functions and targeted genes of these differentially expressed miRNAs, i.e. Akt3, FGFR3, PSEN1, VEGFa and AR. Subsequently, expression of the selected differentially expressed miRNAs (Hsa­miR­4795­5p, Hsa­miR­488, Hsa­miR­4784, Hsa­miR­330, Hsa­miR­3916, Hsa­miR­4274 and Hsa­miR­181c) was validated in another set of tissue samples. A total of 29 miRNAs were identified to be differentially expressed between AAN­UUC and non­AAN­UUC tissues and these miRNA target genes in FGFR3 and Akt pathways, which regulate cell growth and tumor progression, respectively.

Downregulation of homeodomain-interacting protein kinase-2 contributes to bladder cancer metastasis by regulating Wnt signaling.

Homeodomain-interacting protein kinase-2 (Hipk2) has been shown to have important regulatory roles in cancer biology, such as cancer cell proliferation, cell cycle, and cell invasion. However, the contributions of Hipk2 to bladder cancer metastasis remain largely unknown. In the current study, we assayed the expression level of Hipk2 in bladder cancer tissues by real-time PCR, and defined its biological functions. We found that Hipk2 levels were downregulated in most bladder cancer tissues compared with adjacent normal tissues, and Hipk2 levels were remarkably decreased in metastasized tumor tissues when compared with primary tumors. SiRNA-mediated Hipk2 silencing increased bladder cancer cell invasion. Hipk2 knockdown resulted in decrease of E-cadherin expression and increase of N-cadherin and fibronectin expression, indicated that epithelial-mesenchymal transition (EMT) was induced. We further demonstrated that Hipk2 knockdown induced Wnt signaling activation and ß-catenin nuclear localization. Finally, we confirmed that Hipk2 inhibition promoted EMT and subsequent cell invasion, at least in part by activating Wnt signaling. These data suggest an important role of Hipk2 in regulating metastasis of bladder cancer and implicate the potential application of Hipk2 in bladder cancer therapy.

Downregulation of GAS5 promotes bladder cancer cell proliferation, partly by regulating CDK6.

UNLABELLED: Long non-coding RNAs (lncRNAs) play important roles in diverse biological processes, such as transcriptional regulation, cell growth and tumorigenesis. However, little is known about whether lncRNA-GAS5 (growth arrest-specific 5) regulates bladder cancer progression. In the present study, we found that the GAS5 expression is commonly downregulated in bladder cancer cell lines and human specimens. Knockdown of GAS5 promotes bladder cancer cell proliferation, whereas forced expression of GAS5 suppresses cell proliferation. We further demonstrated that knockdown of GAS5 increases CDK6 mRNA and protein levels in bladder cancer cells. Expectedly, GAS5 inhibition induces a significant decrease in G0/G1 phase and an obvious increase in S phase. Gain-of-function and loss-of-function studies showed that GAS5 inhibits bladder cancer cell proliferation, at least in part, by regulating CDK6 expression. CONCLUSIONS: Downregulated GAS5 promotes bladder cancer cell proliferation, partly by regulating CDK6, and thus may be helpful in the development of effective treatment strategies against bladder cancer.

Knockdown of regulator of cullins-1 (ROC1) expression induces bladder cancer cell cycle arrest at the G2 phase and senescence.

Regulator of Cullins-1 (ROC1) is a key subunit in the Cullin-RING ligase (CRL) protein complex. Overexpression of ROC1 protein is associated with tumor progression and poor prognosis of non-muscle invasive bladder transitional cell carcinoma (NMIBC). This study was designed to assess the effects of ROC1 knockdown in bladder cancer cells and to determine the potential mechanisms involved. A total of 112 bladder cancer tissue specimens were recruited for immunohistochemical analyses of ROC1 overexpression. Bladder cancer cell lines were used to knockdown ROC1 expression using ROC1 siRNA. Our data showed that ROC1 knockdown remarkably inhibited bladder cancer cell growth, arrested cells at the G2 phase of the cell cycle, and induced the p53-dependent cell senescence. Molecularly, G2 arrest was associated with upregulation of p21, p27, cyclin B1, and Cdc2 proteins. ROC1 knockdown induced-senescence functioned through p53/p21 pathway. Knockdown of p21 expression partially rescued ROC1 knockdown-induced growth inhibition in cancer cells. Furthermore, nude mouse xenograft analyses confirmed these in vitro data. In conclusion, data from the current study indicate that ROC1 plays an essential role in bladder cancer progression and could serve as a novel anticancer target for bladder transitional cell carcinoma (BTCC).

Overexpression of RING box protein-1 (RBX1) associated with poor prognosis of non-muscle-invasive bladder transitional cell carcinoma.

BACKGROUND AND OBJECTIVE: RING box protein-1 (RBX1) is a key subunit of the ubiquitin E3 ligase Skp1/Cullin1/Rbx1/F-box protein complex. Altered expression RBX1 is shown to associate with tumorigenesis and tumor progression. This study detected RBX1 expression for association with clinical significance (such as clinicopathological data and survival of the patients) in non-muscle-invasive bladder transitional cell carcinoma (NMIBC). METHODS: A total of 70 primary NMIBC tissue specimens and 24 normal tissue specimens were recruited and analyzed immunohistochemically for expression of RBX1 protein and associated with clinicopathological data and survival of the patients. RESULTS: RBX1 was highly expressed in NMIBC, but was lowly expressed in the normal tissue. RBX1 expression was associated with high tumor grade and advanced clinical stage (P < 0.01 and P < 0.05, respectively). Moreover, patients with high RBX1 expression had shorter recurrence-free survival and progression-free survival rates (P < 0.001 and P < 0.01, respectively). Multivariate analysis demonstrated that RBX1 expression is an independent prognostic factor for tumor recurrence and progression of NMIBC (P < 0.05). CONCLUSIONS: Overexpression of RBX1 protein contributes to tumor progression and poor prognosis of NMIBC.

Upregulated H19 contributes to bladder cancer cell proliferation by regulating ID2 expression.

Long noncoding RNAs have been shown to have important regulatory roles in cancer biology, and long noncoding RNA 19 (H19) is essential for human tumor growth. However, little is known about how abnormal expression of H19 contributes to bladder cancer cell proliferation. In this study, we first evaluated the expression of H19 in bladder cancer tissues by real-time PCR, and defined the biological functions. We found that H19 expression levels were remarkably increased in bladder cancer tissues as compared with adjacent normal control tissue, and forced expression of H19 promoted bladder cancer cell proliferation in vitro. Inhibitor of DNA binding/differentiation 2 (ID2) expression levels were upregulated in bladder cancer tissues and in bladder cancer cells. A significant positive correlation was observed between H19 levels and ID2 levels in vivo. We further demonstrated that overexpression of H19 resulted in a significant increase in the expression of ID2, whereas H19 knockdown decreased ID2 expression in vitro. Gain-of-function and loss-of-function studies demonstrated that upregulated H19 increased bladder cancer cell proliferation by increasing ID2 expression. In conclusion, upregulated H19 increases bladder cancer growth by regulating ID2 expression, and thus may be helpful in the development of effective treatment strategies for bladder cancer.

Long non-coding RNA H19 increases bladder cancer metastasis by associating with EZH2 and inhibiting E-cadherin expression.

lncRNA H19 is essential for human tumor growth. However, little is known about whether H19 regulates bladder cancer metastasis. Here we found that H19 levels are remarkably increased in bladder cancer tissues, and upregulated H19 promotes bladder cancer cell migration in vitro and in vivo. H19 is associated with enhancer of zeste homolog 2 (EZH2), and that this association results in Wnt/ß-catenin activation and subsequent downregulation of E-cadherin. A significant negative correlation is also observed between H19 levels and E-cad levels in vivo. These data suggest that upregulated H19 enhances bladder cancer metastasis by associating with EZH2 and inhibiting E-cad expression.