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Abstract Background Heparanase facilitates the invasion and metastasis of cancer cells, and is over-expressed in many kinds of malignancies. Our studies indicated that heparanase was frequently expressed in advanced gastric cancers. The aim of this study is to determine whether silencing of heparanase expression can abolish the malignant characteristics of gastric cancer cells. Methods Three heparanase-specific small interfering RNA (siRNAs) were designed, synthesized, and transfected into cultured gastric cancer cell line SGC-7901. Heparanase expression was measured by RT-PCR, real-time quantitative PCR and Western blot. Cell proliferation was detected by MTT colorimetry and colony formation assay. The in vitro invasion and metastasis of cancer cells were measured by cell adhesion assay, scratch assay and matrigel invasion assay. The angiogenesis capabilities of cancer cells were measured by tube formation of endothelial cells. Results Transfection of siRNA against 1496-1514 bp of encoding regions resulted in reduced expression of heparanase, which started at 24 hrs and lasted for 120 hrs post-transfection. The siRNA-mediated silencing of heparanase suppressed the cellular proliferation of SGC-7901 cells. In addition, the in vitro invasion and metastasis of cancer cells were attenuated after knock-down of heparanase. Moreover, transfection of heparanase-specific siRNA attenuated the in vitro angiogenesis of cancer cells in a dose-dependent manner. Conclusions These results demonstrated that gene silencing of heparanase can efficiently abolish the proliferation, invasion, metastasis and angiogenesis of human gastric cancer cells in vitro, suggesting that heparanase-specific siRNA is of potential values as a novel therapeutic agent for human gastric cancer.

Recent findings have unraveled the critical functions of the long noncoding RNA (lncRNA) SNHG5 in human malignancies. Nevertheless, the role and mechanism of SNHG5 in clear cell renal cell carcinoma (ccRCC) are still elusive. In our study, substantially higher abundance of SNHG5 was observed in ccRCC specimens and cell lines, and increased SNHG5 expression was intimately correlated with tumor size, tumor‐node‐metastasis (TNM) stage, lymph node invasion, and distant metastases in patients with ccRCC. SNHG5 knockdown obviously suppressed the proliferative, migratory, and invasive capabilities of ccRCC cells, whereas SNHG5 overexpression induced the opposite effects. Mechanistically, SNHG5 activated the transcription of ZEB1, which exerts a pivotal role in modulation of epithelia‐mesenchymal transition (EMT) and tumor metastasis. SNHG5 was then shown to act as an endogenous sponge for miR‐205‐5p, which targets ZEB1 in ccRCC. Moreover rescue experiments revealed that SNHG5 promotes ccRCC cell proliferation, migration, and invasion in a miR‐205‐5p‐dependent manner. Additionally, in vivo assays further indicated that overexpression or silencing of SNHG5 in ccRCC cells promoted or suppressed the tumorigenesis and metastasis, respectively. Altogether, the present data provide the first evidence that the lncRNA SNHG5 has an oncogenic role in ccRCC through the SNHG5/miR‐205‐5p/ZEB1 signaling axis and represents a novel potential therapeutic regimen against ccRCC. [ABSTRACT FROM AUTHOR]

Our recent studies demonstrate that X‐linked inhibitor of apoptosis protein (XIAP) is essential for regulating colorectal cancer invasion. Here, we discovered that RhoGDIβ was a key XIAP downstream effector mediating bladder cancer (BC) invasion in vitro and in vivo. We found that both XIAP and RhoGDIβ expressions were consistently elevated in BCs of N‐butyl‐N‐(4‐hydroxybutyl)‐nitrosamine (BBN)‐treated mice in comparison to bladder tissues from vehicle‐treated mice and human BCs in comparison to the paired adjacent normal bladder tissues. Knockdown of XIAP attenuated RhoGDIβ expression and reduced cancer cell invasion, whereas RhoGDIβ expression was attenuated in BBN‐treated urothelium of RING‐deletion knockin mice. Mechanistically, XIAP stabilized RhoGDIβ mRNA by its positively regulating nucleolin mRNA stability via Erks‐dependent manner. Moreover, ectopic expression of GFP‐RhoGDIβ in T24T(shXIAP) cells restored its lung metastasis in nude mice. Our results demonstrate that XIAP‐regulated Erks/nucleolin/RhoGDIβ axis promoted BC invasion and lung metastasis. [ABSTRACT FROM AUTHOR]

Increasing evidences suggest that circular RNAs (circ RNAs) exert crucial functions in regulating gene expression. In this study, we perform RNA-seq and identify 6,154 distinct circ RNAs from human bladder cancer and normal bladder tissues. We find that hundreds of circ RNAs are significantly dysregulated in human bladder cancer tissues. We further show that circ HIPK3, also named bladder cancer-related circular RNA-2 ( BCRC-2), is significantly down-regulated in bladder cancer tissues and cell lines, and negatively correlates with bladder cancer grade, invasion as well as lymph node metastasis, respectively. Over-expression of circ HIPK3 effectively inhibits migration, invasion, and angiogenesis of bladder cancer cells in vitro and suppresses bladder cancer growth and metastasis in vivo. Mechanistic studies reveal that circ HIPK3 contains two critical binding sites for the micro RNA miR-558 and can abundantly sponge miR-558 to suppress the expression of heparanase ( HPSE). Taken together, our findings provide evidence that circ RNAs act as 'micro RNA sponges', and suggest a new therapeutic target for the treatment of bladder cancer. [ABSTRACT FROM AUTHOR]

Cisplatin (CDDP)-based chemotherapy is the first-line treatment for muscle-invasive and metastatic bladder cancer, yet most patients rapidly develop resistance. N6-methyladenosine (m 6 A) methylation is a pervasive RNA modification, and its specific role and potential mechanism in the regulation of CDDP chemosensitivity in bladder cancer remain unclear. Furthermore, studies have not yet fully elucidated whether circular RNA (circRNA) can directly regulate m 6 A modification of mRNA. Here we report upregulation of a novel circRNA, hsa_circ_0008399 ( circ0008399 ), by eukaryotic translation initiation factor 4A3 (EIF4A3) in bladder cancer tissues and cell lines. Functionally, circ0008399 inhibited apoptosis of bladder cancer cells. Mechanistically, circ0008399 bound Wilms' tumor 1-associating protein (WTAP) to promote formation of the WTAP/METTL3/METTL14 m 6 A methyltransferase complex. Circ0008399 increased expression of TNF alpha-induced protein 3 (TNFAIP3) by increasing its mRNA stability in an m 6 A-dependent manner. In patients with bladder cancer, high expression of circ0008399 and WTAP was associated with poor outcomes. Importantly, activation of the circ0008399 /WTAP/TNFAIP3 pathway decreased bladder cancer chemosensitivity to CDDP, and targeting the circ0008399 /WTAP/TNFAIP3 axis enhanced the CDDP efficacy. Collectively, these findings give novel insights into circRNA-mediated regulation of m 6 A modifications and provide potential therapeutic targets for bladder cancer. SIGNIFICANCE: A newly characterized circRNA circ0008399 binds WTAP to modulate expression of target RNA through m 6 A modification and reduce cisplatin sensitivity in bladder cancer, implicating the potential therapeutic value of targeting this axis., (©2021 American Association for Cancer Research.)

Our recent studies demonstrate that X-linked inhibitor of apoptosis protein (XIAP) is essential for regulating colorectal cancer invasion. Here, we discovered that RhoGDIβ was a key XIAP downstream effector mediating bladder cancer (BC) invasion in vitro and in vivo. We found that both XIAP and RhoGDIβ expressions were consistently elevated in BCs of N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN)-treated mice in comparison to bladder tissues from vehicle-treated mice and human BCs in comparison to the paired adjacent normal bladder tissues. Knockdown of XIAP attenuated RhoGDIβ expression and reduced cancer cell invasion, whereas RhoGDIβ expression was attenuated in BBN-treated urothelium of RING-deletion knockin mice. Mechanistically, XIAP stabilized RhoGDIβ mRNA by its positively regulating nucleolin mRNA stability via Erks-dependent manner. Moreover, ectopic expression of GFP-RhoGDIβ in T24T(shXIAP) cells restored its lung metastasis in nude mice. Our results demonstrate that XIAP-regulated Erks/nucleolin/RhoGDIβ axis promoted BC invasion and lung metastasis., (© 2017 UICC.)

Pituitary tumor-transforming gene 1 (PTTG1) is identified as an oncogene, and overexpresses in many tumors. However, the role of PTTG1 in bladder cancer (BC) hasn't yet been characterized well. In this study, we showed the expression of PTTG1 mRNA and protein were both significantly increased in BC tissues and cells. The PTTG1 protein levels were positive correlated with increased tumor size, tumor-node-metastasis (TNM) stage, lymphatic invasion and distant metastasis of BC. PTTG1 knockdown dramatically suppressed the migration, invasion, metastasis and growth, and induced senescence and cell-cycle arrest at G0/G1 phase of BC cells. We further identified PTTG1 was the direct target of miR-146a-3p through using target prediction algorithms and luciferase reporter assay. miR-146a-3p was low expressed and negatively correlated with PTTG1 levels in BC tissues and cells. miR-146a-3p overexpression inhibited migration, invasion, metastasis and growth, and induced senescence of BC cells. Rescue experiment suggested ectopic expression of miR-146a-3p and PTTG1 suppressed migration, invasion and induced cell cycle arrest and senescence of BC cells compared to PTTG1 overexpression, confirming miR-146a-3p inhibited BC progression by targeting PTTG1. In summary, our study found miR-146a-3p/PTTG1 axis regulated BC migration, invasion, metastasis and growth, and might be a targets for BC therapy.

Background: Glioblastoma (GBM) is the most common malignant brain tumor, and glioma stem cells (GSCs) are considered a major source of treatment resistance for glioblastoma. Identifying new compounds that inhibit the growth of GSCs and understanding their underlying molecular mechanisms are therefore important for developing novel therapy for GBM., Methods: We investigated the potential inhibitory effect of isorhapontigenin (ISO), an anticancer compound identified in our recent investigations, on anchorage-independent growth of patient-derived glioblastoma spheres (PDGS) and its mechanism of action., Results: ISO treatment resulted in significant anchorage-independent growth inhibition, accompanied with cell cycle G0-G1 arrest and cyclin D1 protein downregulation in PDGS. Further studies established that cyclin D1 was downregulated by ISO at transcription levels in a SOX2-dependent manner. In addition, ISO attenuated SOX2 expression by specific induction of miR-145, which in turn suppressed 3'UTR activity of SOX2 mRNA without affecting its mRNA stability. Moreover, ectopic expression of exogenous SOX2 rendered D456 cells resistant to induction of cell cycle G0-G1 arrest and anchorage-independent growth inhibition upon ISO treatment, whereas inhibition of miR-145 resulted in D456 cells resistant to ISO inhibition of SOX2 and cyclin D1 expression. In addition, overexpression of miR-145 mimicked ISO treatment in D456 cells., Conclusions: ISO induces miR-145 expression, which binds to the SOX2 mRNA 3'UTR region and inhibits SOX2 protein translation. Inhibition of SOX2 leads to cyclin D1 downregulation and PDGS anchorage-independent growth inhibition. The elucidation of the miR-145/SOX2/cyclin D1 axis in PDGS provides a significant insight into understanding the anti-GBM effect of ISO compound., (© The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

MiR-138 has been shown to be downregulated in various cancers, including head and neck squamous cell carcinoma (HNSCC) and clear cell renal carcinoma (ccRCC). In the present study, we aimed to reveal the mechanism of miR-138 induction of senescence in renal carcinoma cells and identify its specific target genes. We used qRT-PCR to analyze miR-138 expression levels in renal carcinoma cell lines and ccRCC samples. The activity of β-galactosidase was measured for functional analysis after miR-138 mimic transfection. To identify the targets of miR-138, we used three types of target prediction software to determine three candidate target genes. Furthermore, a 3'UTR luciferase assay was performed. Western blotting was used to detect the protein expression levels of candidate target genes. Additionally, knockdown of EZH2 by its siRNA was performed. The expression of miR-138 was downregulated in RCC cells lines and in tumor samples compared with their controls. Transfection of miR-138 mimic induced SN-12 cell senescence, decreased the protein expression of EZH2, and increased the protein expression of P16. Furthermore, miR-138 decreased the 3'UTR luciferase activity of EZH2. The knockdown of EZH2 by siRNA induced SN-12 cell senescence, decreased the protein expression level of EZH2, and increased the protein expression of P16. MiR-138 is a tumor-suppressor miRNA in ccRCC that induces SN-12 cell senescence by downregulating EZH2 expression and upregulating P16 expression.