Jianxin Qiu

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/β-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.

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.

Downregulation of GAS5 Promotes Bladder Cancer Cell Proliferation, Partly by Regulating CDK6

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.

Macrophages Regulate Renal Fibrosis Through Modulating TGFβ Superfamily Signaling

Renal fibrosis is the fundamental pathway leading to end-stage renal disease, while its exact molecular basis remains incompletely elucidated. Previous studies have demonstrated that transforming growth factor beta 1 (TGFβ1) is an inducer of the epithelial-to-mesenchymal transition (EMT) of renal tubular epithelial cells, while bone morphogenic protein 7 (BMP7) counteracts TGFβ1-induced EMT and reverses chronic renal injury. Although macrophage recruitment is believed to play an important role during the whole pathogenesis, the mechanism underlying their activate involvement in the formation of renal fibrosis besides phagocytosizing extracellular matrix and apoptotic cells is largely unknown. Here, in a mouse unilateral ureteral obstruction (UUO) model, we show that the recruited macrophages are mainly M1 macrophages at early stage. However, these F4/80-positive and CD301-negative M1 macrophages were shortly polarized into F4/80-positive and CD301-positive M2 macrophages, respectively, which released high levels TGFβ1, to contradict the local expression of BMP7 to facilitate EMT-induced renal fibrosis. M2 macrophages depletion specifically inhibited EMT, and subsequently the renal fibrosis. Adoptive transplantation of M2 macrophages increased the features of renal fibrosis. Our study thus identified double-edged effects of macrophages in the formation of renal fibrosis, which suggest that modulation of macrophage polarization may substantially improve the treatment of renal fibrosis.

SUMO-specific protease 2 suppresses cell migration and invasion through inhibiting the expression of MMP13 in bladder cancer cells.

Background: SUMO-specific protease 2 (SENP2) is a de-SUMOylation protease family member which has an indispensable role in the regulation of NF-κB transcriptional activation and Wnt signaling. However, whether SENP2 plays a role in tumor metastasis is completely unknown. Methods: Real-time PCR and Western blot was used to detect the expression of SENP2 in human bladder cancer samples and cell lines. Small interfering RNA (siRNA) was used to silencing the expression of SENP2. Matrigel-coated invasion chambers were used to detect the invasion ability of SENP2 in bladder cancer cells. Results: SENP2 was down-regulated in bladder cancer samples. SENP2 inhibited bladder cancer cells migration and invasion in vitro. Transcriptional analysis of several genes associated with tumor metastasis and invasion demonstrated that SENP2 selectively down-regulated MMP13 in bladder cancer cells. Further analysis indicated that silencing of MMP13 rescued the invasive phenotype in SENP2 expressing T24 cells. Conclusion: SENP2 functions as a tumor metastasis suppressor in bladder cancer. The effects of SENP2 on bladder cancer invasion are partially mediated by inhibiting the expression of MMP13.

Polymorphisms in cytotoxic T lymphocyte associated antigen-4 influence the rate of acute rejection after renal transplantation in 167 Chinese recipients.

Gene polymorphisms of cytotoxic T lymphocyte associated antigen 4 (CTLA4) play an influential role in the graft rejection and long-term clinical outcome of organ transplantation. We investigated the associations of five CTLA4 single nucleotide polymorphisms (SNPs) (rs733618T/C, rs4553808A/G, rs5742909C/T, rs231775G/A, rs3087243G/A) on the early acute rejection (AR) of Chinese deceased donor renal transplantation recipients. Genotyping of the CTLA4 SNPs was performed in 167 deceased donor renal transplantation recipients. Each patient underwent a 6-month follow-up observation for AR. The incidence of AR during the 6 months post-transplantation was 26.9% (45 out of 167 patients). Patients experiencing AR were found to have a higher frequency of the rs733618TT genotype and T allele (p=0.000 and p=0.002, respectively). While the haplotype CACAG was merely observed in non-AR group (corrected p=0.000), the frequency of haplotype TACGG was significantly higher in AR group than in non-AR group even after 50,000 permutation tests (corrected p=0.018). In conclusion, these polymorphisms statistically significantly associated with acute renal allograft rejection may be considered as a risk factor of AR in Chinese renal transplantation recipients except for haplotype CACAG as a protective one.

The CXCL12 G801A polymorphism and cancer risk: Evidence from 17 case-control studies

CXCL12 has been implicated in human carcinogenesis, but the association between the most-studied G801A polymorphism (rs1801157) and the risk of various cancers was reported with inconclusive results. The aim of this study was to assess the association between the CXCL12 G801A polymorphism and cancer risk. A meta-analysis of 17 studies with 3048 cancer patients and 4522 controls was conducted to evaluate the strength of the association using odds ratio (OR) with its 95% confidence interval (CI). The overall results showed that the variant genotypes were associated with a significantly increased risk of all cancer types (OR=1.38, 95%CI=1.18-1.61 for GA versus GG, and OR=1.36, 95%CI=1.17-1.59 for GA/AA versus GG). In the stratified analyses, there was a significantly increased risk for the studies of breast cancer (OR=1.64, 95% CI=1.16-2.33 for AA versus GG, OR=1.42, 95%CI=1.18-1.71 for GA versus GG, and OR=1.44, 95%CI=1.21-1.72 for GA/AA versus GG) and lung cancer (OR=2.86, 95% CI=1.75-4.69 for AA versus GG, OR=1.62, 95% CI=1.20-2.18 for GA vs. GG, OR=1.80, 95% CI=1.36-2.39 for GA/AA versus GG, and OR=2.24, 95%CI=1.41-3.57 for AA versus GA/GG), which remained for the studies of Asian populations and hospital-based control sources. Although some modest bias could not be eliminated, this meta-analysis indicates that the CXCL12 G801A polymorphism is a low-penetrance risk factor for cancer development.

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 β‐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. J. Cell. Biochem. 115: 1762–1767, 2014.

CCR2 Positive Exosome Released by Mesenchymal Stem Cells Suppresses Macrophage Functions and Alleviates Ischemia/Reperfusion-Induced Renal Injury

Mesenchymal stem cells (MSCs) derived exosomes have been shown to have protective effects on the kidney in ischemia/reperfusion-induced renal injury. However, the key components in the exosomes and their potential mechanisms for the kidney protective effects are not well understood. In our current study, we focused on the abundant proteins in exosomes derived from MSCs (MSC-exo) and found that the C-C motif chemokine receptor-2 (CCR2) was expressed on MSC-exo with a high ability to bind to its ligand CCL2. We also proved that CCR2 high-expressed MSC-exo could reduce the concentration of free CCL2 and suppress its functions to recruit or activate macrophage. Further, knockdown of CCR2 expression on the MSC-exo greatly abolished these effects. Finally, we also found that CCR2 knockdown impaired the protective effects of MSC-exo for the renal ischemia/reperfusion injury in mouse. The results indicate that CCR2 expressed on MSC-exo may play a key role in inflammation regulation and renal injury repair by acting as a decoy to suppress CCL2 activity. Our study may cast new light on understanding the functions of the MSC-exo and these receptor proteins expressed on exosomes.

Induction of Regulatory B-Cells by Mesenchymal Stem Cells is Affected by SDF-1α-CXCR7

Background/Aims: Mesenchymal stem cells (MSCs) possess immunomodulatory properties on a diverse array of immune cell lineages, including regulatory T and B cells (Tregs and Bregs, respectively). However, their specific effects and mechanisms underlying induction of Bregs remain unclear. The immune regulatory function of MSCs is exerted through both cell-cell contact and the release of soluble factors. The main objective of this study was to examine the role of the SDF-1-CXCR4/CXCR7 axis in the secretory action of MSCs, and potential effects on the immunoregulatory function of these cells. Methods: MSCs were isolated from mouse bone marrow and characterized according to their multilineage differentiation potential and their surface antigen expression. CD19+ B cells purified from mice splenocytes were co-cultured with MSCs at various ratios in the presence of LPS and αCD40. After 4 days, intracellular IL-10 production and cell surface CD1d and CD5 expression by CD19+ B cells were determined using flow cytometry, and the secretion of IL-10, IL-6, IgM, and IgG were assessed with ELISA. MSCs were treated with different concentrations of stromal derived factor-1α (SDF-1α) stimuli or transiently overexpressed with CXCR7. and their cell viability and immune regulatory effects of MSCs on Bregs were assessed. Results: MSCs induced IL-10-producing regulatory B cells and primarily stimulated the CD1d+CD5+B cell subset of IL-10+Breg cells to express IL-10. IL-10, IL-6, and IgM secretion were additionally induced by MSCs. The CXCR7 pathway was required for MSC viability and the production of paracrine factors under SDF-1α culture condition. Low concentrations of SDF-1α promoted the immunomodulatory effect of MSCs, leading to a further increase in IL-10-producing regulatory B cells and IL-10 secretion. In contrast, high concentrations of SDF-1α inhibited MSCs induction of IL-10+Breg cells. Notably, CXCR7 overexpression in MSCs reversed the inhibitory effect of high concentrations of SDF-1α and promoted the immunomodulatory effect of these cells. Conclusion: MSCs induce IL-10+Breg cells, which contribute to the generation of an immunosuppressive environment. SDF-1α and its receptor, CXCR7 play important roles in the immunomodulatory function of MSCs by regulating their paracrine actions.