Promotes Bladder Cancer Metastasis Research Articles

M6A-Mediated Induction of 7-Dehydrocholesterol Reductase Stimulates Cholesterol Synthesis and cAMP Signaling to Promote Bladder Cancer Metastasis.

Dysregulation of cholesterol homeostasis occurs in multiple types of tumors and promotes cancer progression. Investigating the specific processes that induce abnormal cholesterol metabolism could identify therapeutic targets to improve cancer treatment. In this investigation, we observed upregulation of 7-dehydrocholesterol reductase (DHCR7), a vital enzyme involved in the synthesis of cholesterol, within bladder cancer tissues in comparison to normal tissues, which was correlated with increased bladder cancer metastasis. Increased expression of DHCR7 in bladder cancer was attributed to decreased mRNA degradation mediated by YTHDF2. Loss or inhibition of DHCR7 reduced bladder cancer cell invasion in vitro and metastasis in vivo. Mechanistically, DHCR7 promoted bladder cancer metastasis by activating the cAMP/protein kinase A/FAK pathway. Specifically, DHCR7 increased cAMP levels by elevating cholesterol content in lipid rafts, thereby facilitating the transduction of signaling pathways mediated by cAMP receptors. DHCR7 additionally enhanced the cAMP signaling pathway by reducing the concentration of 7-dehydrocholesterol and promoting the transcription of the G protein-coupled receptor, namely gastric inhibitory polypeptide receptor. Overall, these findings demonstrate that DHCR7 plays an important role in bladder cancer invasion and metastasis by modulating cholesterol synthesis and cAMP signaling. Furthermore, inhibition of DHCR7 shows promise as a viable therapeutic strategy for suppressing bladder cancer invasion and metastasis. Significance: Inhibiting DHCR7 induces cholesterol metabolism reprogramming and lipid raft remodeling to inactivate the cAMP/protein kinase A/FAK axis and suppress bladder cancer metastasis, indicating the therapeutic potential of targeting DHCR7.

Complement regulatory protein CD46 promotes bladder cancer metastasis through activation of MMP9.

CD46, a transmembrane protein known for protecting cells from complement‑mediated damage, is frequently dysregulated in various types of cancer. Its overexpression in bladder cancers safeguards the cancer cells against both complement and antibody‑mediated cytotoxicity. The present study explored a new role of CD46 in facilitating cancer cell invasion and metastasis, examining its regulatory effect on matrix metalloproteases (MMPs) and their effect on the metastatic capability of bladder cancer cells. Specifically, CD46 alteration positively influenced MMP9 expression, but not MMP2, in several bladder cancer cell lines. Furthermore, CD46 overexpression triggered phosphorylation of p38 MAPK and protein kinase B (AKT), leading to enhanced activator protein 1 (AP‑1) activity via c‑Jun upregulation. The inhibition of p38 or AKT pathways attenuated the CD46‑induced MMP9 and AP‑1 upregulation, indicating that the promotion of MMP9 by CD46 involved activating both p38 MAPK and AKT. Functionally, the upregulation of MMP9 by CD46 translated to increased migratory and invasive capabilities of bladder cancer cells, as well as enhanced in vivo metastasis. Overall, the present study revealed a novel role for CD46 as a metastasis promoter through MMP9 activation in bladder cancers and highlighted the regulatory mechanism of CD46‑mediated MMP9 promotion via p38 MAPK and AKT activation.

EIF4A3-mediated biogenesis of circSTX6 promotes bladder cancer metastasis and cisplatin resistance

BackgroundCisplatin (CDDP)-based chemotherapy is a standard first-line treatment for metastatic bladder cancer (BCa) patients, and chemoresistance remains a major challenge in clinical practice. Circular RNAs (circRNAs) have emerged as essential regulators in carcinogenesis and cancer progression. However, the role of circRNAs in mediating CDDP chemosensitivity has yet to be well elucidated in BCa.MethodsCircSTX6 (hsa_circ_0007905) was identified by mining the public circRNA datasets and verified by Sanger sequencing, agarose gel electrophoresis, RNase R treatment and qRT-PCR assays. Then, function experiments were performed to evaluate the effects of circSTX6 on BCa metastasis. Luciferase reporter assay, RNA pull-down, RNA immunoprecipitation (RIP), RNA stability assay, Fluorescence in situ hybridization (FISH) and Immunofluorescence (IF) were conducted to evaluate the interaction among circSTX6, miR-515-3p, PABPC1 and SUZ12. Animal experiments were performed to explore the function of circSTX6 in tumor metastasis and CDDP sensitivity.ResultsWe identified that circSTX6 was significantly upregulated in clinical samples and cells of BCa. Functionally, circSTX6 promoted cell migration and invasion both in vitro and in vivo. Mechanistically, circSTX6 could act as a miR-515-3p sponge and abolish its effect on SUZ12. Moreover, circSTX6 was confirmed to increase the stability of SUZ12 mRNA by interacting with a mRNA stabilizer PABPC1 and subsequently promote the expression of SUZ12. Importantly, silencing of circSTX6 improved the chemosensitivity of CDDP-resistant bladder cancer cells to CDDP. Furthermore, in vivo analysis supported that knockdown of circSTX6 attenuated CDDP resistance in BCa tumors.ConclusionThese studies demonstrate that circSTX6 plays a pivotal role in BCa metastasis and chemoresistance, and has potential to serve as a therapeutic target for treatment of BCa.

SBSN drives bladder cancer metastasis via EGFR/SRC/STAT3 signalling.

Patients with metastatic bladder cancer have very poor prognosis and predictive biomarkers are urgently needed for early clinical detection and intervention. In this study, we evaluate the effect and mechanism of Suprabasin (SBSN) on bladder cancer metastasis. A tissue array was used to detect SBSN expression by immunohistochemistry. A tumour-bearing mouse model was used for metastasis evaluation in vivo. Transwell and wound-healing assays were used for in vitro evaluation of migration and invasion. Comprehensive molecular screening was achieved by western blotting, immunofluorescence, luciferase reporter assay, and ELISA. SBSN was found markedly overexpressed in bladder cancer, and indicated poor prognosis of patients. SBSN promoted invasion and metastasis of bladder cancer cells both in vivo and in vitro. The secreted SBSN exhibited identical biological function and regulation in bladder cancer metastasis, and the interaction of secreted SBSN and EGFR could play an essential role in activating the signalling in which SBSN enhanced the phosphorylation of EGFR and SRC kinase, followed with phosphorylation and nuclear location of STAT3. Our findings highlight that SBSN, and secreted SBSN, promote bladder cancer metastasis through activation of EGFR/SRC/STAT3 pathway and identify SBSN as a potential diagnostic and therapeutic target for bladder cancer.

Loss of polarity protein Par3, via transcription factor Snail, promotes bladder cancer metastasis.

Bladder cancer (BLCA) remains the leading cause of cancer‐related mortality among genitourinary malignancies worldwide. BLCA metastasis represents the primary reason for its poor prognosis. In this study, we report that decreased expression of partitioning defective 3 (Par3), a polarity protein (encoded by PARD3), is associated with tumor aggressive phenotypes and poor prognosis in BLCA patients. Consistently, ablation of Par3 promotes the metastasis and invasion of BLCA cells in vitro and in vivo. Further studies reveal that zinc finger protein Snail represses the expression of Par3 by binding to E2‐box (CAGGTG) of PARD3 promoter‐proximal. Inhibition of GSK‐3β promotes the expression and nuclear localization of Snail and then reduces the expression of Par3, resulting in the metastasis and invasion of BLCA cells. Moreover, we detected the interaction between Par3 (936‐1356 aa) and ZO‐1 (1372‐1748 aa), which is involved in the maintenance of tight junction. Together, our results demonstrate that the GSK‐3β/Snail/Par3/ZO‐1 axis regulates BLCA metastasis, and Snail is a major regulator for Par3 protein expression in BLCA.

KNSTRN promotes tumorigenesis and gemcitabine resistance by activating AKT in bladder cancer.

KNSTRN is a component of the mitotic spindle, which was rarely investigated in tumorigenesis. AKT plays an essential role in tumorigenesis by modulating the phosphorylation of various substrates. The activation of AKT is regulated by PTEN and PIP3. Here, we prove KNSTRN is positively correlated with malignancy of bladder cancer and KNSTRN activates AKT phosphorylation at Thr308 and Ser473. More importantly, our study reveals that both KNSTRN and PTEN interact with PH domain of AKT at cell membrane. The amount of KNSTRN interacted with AKT is negatively related to PTEN. Furthermore, PIP3 pull-down assay proves that KNSTRN promoted AKT movement to PIP3. These data suggest KNSTRN may activate AKT phosphorylation by promoting AKT movement to PIP3 and alleviating PTEN suppression. Based on the activation of AKT phosphorylation, our study demonstrates that KNSTRN promotes bladder cancer metastasis and gemcitabine resistance in vitro and in vivo. Meanwhile, the effect of KNSTRN on tumorigenesis and gemcitabine resistance could be restored by AKT specific inhibitor MK2206 or AKT overexpression. In conclusion, we identify an oncogene KNSTRN that promotes tumorigenesis and gemcitabine resistance by activating AKT phosphorylation and may serve as a therapeutic target in bladder cancer.

MiRNA-516a promotes bladder cancer metastasis by inhibiting MMP9 protein degradation via the AKT/FOXO3A/SMURF1 axis.

BackgroundMetastasis is the leading cause of death in patients with bladder cancer (BC). However, current available treatments exert little effects on metastatic BC. Moreover, traditional grading and staging have only a limited ability to identify metastatic BC. Accumulating evidence indicates that the aberrant expression of microRNA is intimately associated with tumor progression. So far, many miRNAs have been identified as molecular targets for cancer diagnosis and therapy. This study focused on the role of miR‐516a‐5p (miR‐516a) in BC.MethodsMiR‐516a expression and its downstream signaling pathway were detected using molecular cell biology and biochemistry approaches and techniques. Fresh clinical BC tissue was used to study the clinicopathological characteristics of patients with different miR‐516a expression. The biological functions of miR‐516a in BC were tested both in vivo and in vitro.ResultsA more invasive BC phenotype was significantly and positively correlated with miR‐516a overexpression in BC patients. MiR‐516a inhibition significantly decreased BC cell invasion and migration in vitro and in vivo. Furthermore, miR‐516a attenuated the expression of PH domain leucine‐rich repeat‐containing protein phosphatase 2 protein and inhibited SMAD‐specific E3 ubiquitin protein ligase 1 transcription by activating the AKT/Forkhead box O3 signaling pathway, which stabilized MMP9 and slowed down its proteasomal degradation, ultimately promoting BC motility and invasiveness.ConclusionsOur findings reveal the crucial function of miR‐516a in promoting BC metastasis, and elucidate the molecular mechanism involved, suggesting that miR‐516a may be a promising novel diagnostic and therapeutic target for BC.

Androgen receptor suppresses prostate cancer metastasis but promotes bladder cancer metastasis via differentially altering miRNA525-5p/SLPI-mediated vasculogenic mimicry formation.

Early studies suggest that the androgen receptor (AR) may play differential roles in influencing prostate cancer (PCa) and bladder cancer (BCa) metastasis, but the underlying mechanisms remain unclear. Here, we found that the AR might function via differentially altering vasculogenic mimicry (VM) formation to either decrease PCa metastasis or increase BCa metastasis. Mechanism dissection showed that the AR could differentially alter the expression of the VM marker SLPI through miR-525-5p to regulate SLPI; moreover, it could either increase miR-525-5p transcription in PCa or decrease it in BCa via binding to different androgen-response-elements (AREs) located at different positions in the miR-525 precursor promoter. Further, results from liquid chromatography-mass spectrometry (LC-MS) showed that the co-factors of AR in PCa and BCa are NFIX and HDAC2, respectively. Together, these results provide the first detailed mechanism of how the AR can differentially alter PCa and BCa metastasis; thus, targeting the newly identified AR-miR-525-5p-SLPI axis may help suppress metastasis.

P34 - Androgen receptor (AR) suppresses prostate cancer metastasis yet promotes bladder cancer metastasis via differential altering the miRNA525-5p/SLPI-mediated vasculogenic mimicry (VM) formation

P34 - Androgen receptor (AR) suppresses prostate cancer metastasis yet promotes bladder cancer metastasis via differential altering the miRNA525-5p/SLPI-mediated vasculogenic mimicry (VM) formation

TGF-β-induced transgelin promotes bladder cancer metastasis by regulating epithelial-mesenchymal transition and invadopodia formation.

BackgroundMetastatic bladder cancer (BLCA) is a lethal disease with an unmet need for study. Transgelin (TAGLN) is an actin-binding protein that affects the dynamics of the actin cytoskeleton indicating its robust potential as a metastasis initiator. Here, we sought to explore the expression pattern of TAGLN and elucidate its specific functioning and mechanisms in BLCA.MethodsA comprehensive assessment of TAGLN expression in BLCA was performed in three cohorts with a total of 847 patients. The potential effects of TAGLN on BLCA were further determined using clinical genomic analyses that guided the subsequent functional and mechanistic studies. In vitro migration, invasion assays and in vivo metastatic mouse model were performed to explore the biological functions of TAGLN in BLCA cells. Immunofluorescence, western blot and correlation analysis were used to investigate the molecular mechanisms of TAGLN.FindingsTAGLN was highly expressed in BLCA and correlated with advanced prognostic features. TAGLN promoted cell colony formation and cell migration and invasion both in vitro and in vivo by inducing invadopodia formation and epithelial-mesenchymal transition, during which a significant correlation between TAGLN and Slug was observed. The progression-dependent correlation between TGF-β and TAGLN was analysed at both the cellular and tissue levels, while TGF-β-mediated migration was abolished by the suppression of TAGLN.InterpretationOverall, TAGLN is a promising novel prognosis biomarker of BLCA, and its metastatic mechanisms indicate that TAGLN may represent a novel target agent that can be utilized for the clinical management of invasive and metastatic BLCA.FundThis work was supported by the National Natural Science Foundation of China [81772703, 81672546, 81602253]; the Natural Science Foundation of Beijing [71772219, 7152146]. and Innovative Fund for Doctoral Students of Peking University Health Science Center (BUM2018BSS002). Funders had no role in the design of the study, data collection, data analysis, interpretation, or the writing of this report.

1084 - Long noncoding RNA LNMAT2 promotes bladder cancer metastasis by CCL5-dependent macrophage recruitment

1084 - Long noncoding RNA LNMAT2 promotes bladder cancer metastasis by CCL5-dependent macrophage recruitment

Downregulation of miR-200c stabilizes XIAP mRNA and contributes to invasion and lung metastasis of bladder cancer

ABSTRACTOur previous studies have demonstrated that XIAP promotes bladder cancer metastasis through upregulating RhoGDIβ/MMP-2 pathway. However, the molecular mechanisms leading to the XIAP upregulation was unclear. In current studies, we found that XIAP was overexpressed in human high grade BCs, high metastatic human BCs, and in mouse invasive BCs. Mechanistic studies indicated that XIAP overexpression in the highly metastatic T24T cells was due to increased mRNA stability of XIAP that was mediated by downregulated miR-200c. Moreover, the downregulated miR-200c was due to CREB inactivation, while miR-200c downregulation reduced its binding to the 3’-UTR region of XIAP mRNA. Collectively, our results demonstrate the molecular basis leading to XIAP overexpression and its crucial role in BC invasion.

TGF-β-Induced Transgelin Promotes Bladder Cancer Metastasis by Regulating Epithelial-Mesenchymal Transition and Invadopodia Formation

Background: Metastatic bladder cancer (BLCA) is a lethal disease with an unmet need for study. Transgelin (TAGLN) is an actin-binding protein that affects the dynamics of the actin cytoskeleton indicating its robust potential as a metastasis initiator. Here, we sought to explore the expression pattern of TAGLN and elucidate its specific functioning and mechanisms in BLCA. Methods: A comprehensive assessment of TAGLN expression in BLCA was performed in three cohorts with a total of 847 patients. The potential effects of TAGLN on BLCA were further determined using clinical genomic analyses that guided the subsequent functional and mechanistic studies. In vitro migration, invasion assays and in vivo metastatic mouse model were performed to explore the biological functions of TAGLN in BLCA cells. Immunofluorescence, western blot and correlation analysis were used to investigate the molecular mechanisms of TAGLN. Results: TAGLN was highly expressed in BLCA and correlated with advanced prognostic features. TAGLN promoted cell colony formation and cell migration and invasion both in vitro and in vivo by inducing invadopodia formation and epithelial-mesenchymal transition, during which a significant correlation between TAGLN and Slug was observed. The progression-dependent correlation between TGF-β and TAGLN was analysed at both the cellular and tissue levels, while TGF-β-mediated migration was abolished by the suppression of TAGLN. Conclusions: Overall, TAGLN is a promising novel prognosis biomarker of BLCA, and its metastatic mechanisms indicate that TAGLN may represent a novel target agent that can be utilized for the clinical management of invasive and metastatic BLCA. Funding: This work was supported by the National Natural Science Foundation of China [81772703]; the Natural Science Foundation of Beijing [71772219, 7152146]. and Innovative Fund for Doctoral Students of Peking University Health Science Center (BUM2018BSS002). Declaration of Interest: All authors declare that there are no conflicts of interest. Ethical Approval: The studies were conducted in accordance with the approved guidelines. Written informed consent was obtained from all subjects and all experimental protocols were approved by the ethics committee at Peking University First Hospital.

Recruited T cells promote the bladder cancer metastasis via up-regulation of the estrogen receptor β/IL-1/c-MET signals

Clinical data indicates that T cells can be recruited to bladder cancer (BCa), yet the impact of T cells on BCa progression remains unclear. In the present study, we found that T cells were recruited more to BCa tissues than to the surrounding normal bladder tissues. Results from an in vitro co-culture system also found that BCa recruited more CD4+ T cells than did normal bladder cells. The recruiting of T cells to BCa tissues may increase the proliferation and invasion of BCa cells. Mechanistic studies revealed that infiltrating T cells stimulate BCa estrogen receptor beta (ERβ) signaling and consequently increase the expression of MET proto-oncogene, receptor tyrosine kinase (c-MET), through either direct binding to its promoter or via modulation of IL-1 expression. Interruption of ERβ/c-MET or ERβ/IL-1/c-MET signaling via ERβ-shRNA, IL-1 antagonist, or the c-MET inhibitor, SU11274, could partially reverse the T cell-enhanced BCa cell invasion and proliferation. Finally, the mouse BCa model with xenografted BCa 5637 cells with T (HH) cells confirmed the results of in vitro co-culture studies showing that infiltrating T cells could promote BCa metastasis via modulation of the ERβ/c-MET or ERβ/IL-1/c-MET signaling pathways. These findings may provide a new therapeutic approach to better combat BCa progression via targeting these newly identified signaling pathways.

Astrocyte elevated gene-1 promotes invasion and epithelial-mesenchymal transition in bladder cancer cells through activation of signal transducer and activator of transcription 3.

To determine the impact of astrocyte elevated gene-1 on the invasion and epithelial-mesenchymal transition of bladder cancer cells in vitro and metastasis in vivo. Gain- and loss-of-function studies were carried out to investigate the biological roles of astrocyte elevated gene-1 in bladder cancer cell invasion, epithelial-mesenchymal transition and lung metastasis. The mechanism underlying the activity of astrocyte elevated gene-1 was examined. Overexpression of astrocyte elevated gene-1 led to a significant increase in the invasive ability of UMUC3 and T24 bladder cancer cells in Matrigel invasion assays. In contrast, silencing of astrocyte elevated gene-1 restrained bladder cancer cell invasion. Overexpression of astrocyte elevated gene-1 downregulated E-cadherin and upregulated vimentin and Twist1, while silencing of astrocyte elevated gene-1 exerted an opposite effect. Mechanistically, astrocyte elevated gene-1 overexpression promoted the phosphorylation of signal transducer and activator of transcription 3 in bladder cancer cells. Treatment with WP1066, a specific signal transducer and activator of transcription 3 inhibitor, significantly abolished astrocyte elevated gene-1-induced invasion and epithelial-mesenchymal transition in UMUC3 cells. In vivo studies showed that astrocyte elevated gene-1 overexpression stimulated the growth of UMUC3 xenograft tumors and lung metastasis. Astrocyte elevated gene-1 shows the ability to promote bladder cancer metastasis, which is causally linked to induction of signal transducer and activator of transcription 3 activation and epithelial-mesenchymal transition. Therefore, targeting astrocyte elevated gene-1 might offer therapeutic benefits in treating metastatic bladder cancer.

CUL4B promotes bladder cancer metastasis and induces epithelial-to-mesenchymal transition by activating the Wnt/β-catenin signaling pathway.

Increased expression of cullin 4B (CUL4B) is linked to progression in several cancers. This study aims to explore the effects of CUL4B on bladder cancer (BC) metastasis and epithelial-to-mesenchymal transition (EMT) and potential correlation to the Wnt/β-catenin signaling pathway. We collected BC tissues and adjacent normal tissues from 124 BC patients. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were employed in order to detect the expression of Wnt/β-catenin signaling pathway-related proteins and EMT markers. MTT and Transwell assays were used in order to measure cell proliferation, migration, and invasion. BC 5637 cells were transfected with control, siRNA scramble control (siRNA-NC), si-CUL4B, and CUL4B or Wnt inhibitory factor 1 (WIF-1) overexpression constructs. Levels of CUL4B mRNA and protein were increased in BC tissues in comparison with the adjacent normal tissues. CUL4B expression was negatively correlated with the expression of E-cadherin and positively correlated to the expression of N-cadherin and Vimentin. Compared to the control group, levels of β-catenin, cyclinD1, c-myc, MMP7, and EMT markers were reduced, whereas phosphorylated GSK3βSer9 and E-cadherin levels were increased in the si-CUL4B and WIF-1 groups. In addition, cell proliferation, migration, and invasion abilities were also increased. Increasing CUL4B expression had the opposite effect. These findings suggest that CUL4B induces EMT and promotes metastasis of BC by activating the Wnt/β-catenin signaling pathway.

Infiltrating T Cells Promote Bladder Cancer Progression via Increasing IL1→Androgen Receptor→HIF1α→VEGFa Signals.

The tumor microenvironment impacts tumor progression and individual cells, including CD4(+) T cells, which have been detected in bladder cancer tissues. The detailed mechanism of how these T cells were recruited to the bladder cancer tumor and their impact on bladder cancer progression, however, remains unclear. Using a human clinical bladder cancer sample survey and in vitro coculture system, we found that bladder cancer has a greater capacity to recruit T cells than surrounding normal bladder tissues. The consequences of higher levels of recruited T cells in bladder cancer included increased bladder cancer metastasis. Mechanism dissection revealed that infiltrating T cells might function through secreting the cytokine IL1, which increases the recruitment of T cells to bladder cancer and enhances the bladder cancer androgen receptor (AR) signaling that results in increased bladder cancer cell invasion via upregulation of hypoxia-inducible factor-1α (HIF1α)/VEGFa expression. Interruption of the IL1→AR→HIF1α→VEGFa signals with inhibitors of HIF1α or VEGFa partially reversed the enhanced bladder cancer cell invasion. Finally, in vivo mouse models of xenografted bladder cancer T24 cells with CD4(+) T cells confirmed in vitro coculture studies and concluded that infiltrating CD4(+) T cells can promote bladder cancer metastasis via modulation of the IL1→AR→HIF1α→VEGFa signaling. Future clinical trials using small molecules to target this newly identified signaling pathway may facilitate the development of new therapeutic approaches to better suppress bladder cancer metastasis. Mol Cancer Ther; 15(8); 1943-51. ©2016 AACR.

Activated androgen receptor promotes bladder cancer metastasis via Slug mediated epithelial-mesenchymal transition

Androgen receptor (AR) has been indicated to be involved in bladder cancer progression. We showed androgen induced epithelial-mesenchymal transition (EMT) in AR-positive bladder cancer cells and promoted tumor metastasis in xenograft models. We subsequently identified that Slug was the mediator of EMT induced by androgen. Furthermore, upregulation of Slug was due to activation of Wnt/β-catenin signaling in response to androgen. Finally, expression of AR showed strong correlation with loss of E-cadherin, higher expression of Slug and nuclear accumulation of β-catenin in bladder tumor tissues. Taken together, our results suggest AR signaling promotes bladder cancer metastasis through Slug mediated EMT.

TGF-β–Induced Upregulation of malat1 Promotes Bladder Cancer Metastasis by Associating with suz12

TGF-β promotes tumor invasion and metastasis by inducing an epithelial-mesenchymal transition (EMT). However, the underlying mechanisms causing this are not entirely clear. Long noncoding RNAs (lncRNA) have been shown to play important regulatory roles in cancer progression. The lncRNA malat1 (metastasis associated lung adenocarcinoma transcript 1) is a critical regulator of the metastasis phenotype of lung cancer cells. We, therefore, investigated whether TGF-β regulates malat1 expression to promote tumor metastasis of bladder cancer. The expression levels of malat1 and EMT markers were assayed in specimens of bladder cancer. The role of malat1 in regulating bladder cancer metastasis was evaluated in cell and animal models. TGF-β induces malat1 expression and EMT in bladder cancer cells. malat1 overexpression is significantly correlated with poor survival in patients with bladder cancer. malat1 and E-cadherin expression is negatively correlated in vitro and in vivo. malat1 knockdown inhibits TGF-β-induced EMT. malat1 is associated with suppressor of zeste 12 (suz12), and this association results in decrease of E-cadherin expression and increase of N-cadherin and fibronectin expression. Furthermore, targeted inhibition of malat1 or suz12 suppresses the migratory and invasive properties induced by TGF-β. Finally, we demonstrated that malat1 or suz12 knockdown inhibits tumor metastasis in animal models. These data suggest that malat1 is an important mediator of TGF-β-induced EMT, and suggest that malat1 inhibition may represent a promising therapeutic option for suppressing bladder cancer progression.

Overexpression of Rab25 contributes to metastasis of bladder cancer through induction of epithelial–mesenchymal transition and activation of Akt/GSK-3β/Snail signaling

Rab25, an epithelial-specific member of the Rab family of small guanosine triphosphatases, is associated with several human cancers. The goal of this study was to determine its function in bladder cancer (BC). We examined the Rab25 expression pattern in two different cohorts of BC patients treated with radical cystectomy by quantitative PCR, western blotting and immunohistochemical staining. A series of in vitro and in vivo assays were performed to elucidate the function of Rab25 in BC and its underlying mechanisms. Rab25 expression was significantly elevated at both the messenger RNA and protein levels in BCs compared with normal bladder tissues. High Rab25 expression was closely associated with lymph node (LN) metastasis and was an independent predictor for poor disease-free survival in BC patients. Downregulation of Rab25 in BC cells markedly inhibited invasive motility in vitro and metastatic potential in vivo. In addition, downregulation of Rab25 in BC EJ and T24 cells increased the expression levels of epithelial markers (E-cadherin and α-catenin) and decreased the levels of mechamechy markers (vimentin and fibronectin). Simultaneously, downregulation of Rab25 in EJ and T24 cells resulted in the inactivation of downstream phosphorylated protein kinase B (p-Akt), phosphorylated glycogen synthase kinase-β (p-GSK-3β) and snail signaling. This study demonstrates that Rab25 can promote BC metastasis through induction of epithelial-mesenchymal transition process and activation of Akt/GSK-3β/Snail signaling pathway; Rab25 expression level can predict LN metastasis and inferior clinical outcome in BC patients.