Kentaro Jingushi

The miR-130 family promotes cell migration and invasion in bladder cancer through FAK and Akt phosphorylation by regulating PTEN.

Bladder cancer causes an estimated 150,000 deaths per year worldwide. Although 15% of the recurrent bladder cancer becomes an invasive type, currently used targeted therapy for malignant bladder cancer is still not efficient. We focused on the miR-130 family (miR-130b, miR-301a, and miR-301b) that was significantly upregulated in bladder cancer specimens than that of the normal urothelial specimens. We analyzed the functional significance of miR-130 family using a 5637 bladder cancer cell line and revealed that miR-130 family of inhibitors suppressed cell migration and invasion by downregulating focal adhesion kinase (FAK) and Akt phosphorylation. Mechanistic analyses indicate that the miR-130 family directly targets phosphatase and tensin homolog deleted from chromosome 10 (PTEN), resulting in the upregulation of FAK and Akt phosphorylation. In clinical bladder cancer specimens, downregulation of PTEN was found to be closely correlated with miR-130 family expression levels. Overall, the miR-130 family has a crucial role in malignant progression of bladder cancer and thus the miR-130 family could be a promising therapeutic target for invasive bladder cancer.

miR-629 Targets TRIM33 to Promote TGFβ/Smad Signaling and Metastatic Phenotypes in ccRCC

Renal cell carcinoma (RCC) is the most common neoplasm of the adult kidney, and clear cell RCC (ccRCC) represents its most common histological subtype. To identify a therapeutic target for ccRCC, miRNA expression signatures from ccRCC clinical specimens were analyzed. miRNA microarray and real-time PCR analyses revealed that miR-629 expression was significantly upregulated in human ccRCC compared with adjacent noncancerous renal tissue. Functional inhibition of miR-629 by a hairpin miRNA inhibitor suppressed ccRCC cell motility and invasion. Mechanistically, miR-629 directly targeted tripartite motif-containing 33 (TRIM33), which inhibits the TGFβ/Smad signaling pathway. In clinical ccRCC specimens, downregulation of TRIM33 was observed with the association of both pathologic stages and grades. The miR-629 inhibitor significantly suppressed TGFβ-induced Smad activation by upregulating TRIM33 expression and subsequently inhibited the association of Smad2/3 and Smad4. Moreover, a miR-629 mimic enhanced the effect of TGFβ on the expression of epithelial–mesenchymal transition–related factors as well as on the motility and invasion in ccRCC cells. These findings identify miR-629 as a potent regulator of the TGFβ/Smad signaling pathway via TRIM33 in ccRCC. Implications: This study suggests that miR-629 has biomarker potential through its ability to regulate TGFβ/Smad signaling and accelerate ccRCC cell motility and invasion. Mol Cancer Res; 13(3); 565–74. ©2014 AACR.

AlkB homolog 3-mediated tRNA demethylation promotes protein synthesis in cancer cells

The mammalian AlkB homolog (ALKBH) family of proteins possess a 2-oxoglutarate- and Fe(II)-dependent oxygenase domain. A similar domain in the Escherichia coli AlkB protein catalyzes the oxidative demethylation of 1-methyladenine (1-meA) and 3-methylcytosine (3-meC) in both DNA and RNA. AlkB homolog 3 (ALKBH3) was also shown to demethylate 1-meA and 3-meC (induced in single-stranded DNA and RNA by a methylating agent) to reverse the methylation damage and retain the integrity of the DNA/RNA. We previously reported the high expression of ALKBH3 in clinical tumor specimens and its involvement in tumor progression. In this study, we found that ALKBH3 effectively demethylated 1-meA and 3-meC within endogenously methylated RNA. Moreover, using highly purified recombinant ALKBH3, we identified N6-methyladenine (N6-meA) in mammalian transfer RNA (tRNA) as a novel ALKBH3 substrate. An in vitro translation assay showed that ALKBH3-demethylated tRNA significantly enhanced protein translation efficiency. In addition, ALKBH3 knockdown in human cancer cells impaired cellular proliferation and suppressed the nascent protein synthesis that is usually accompanied by accumulation of the methylated RNAs. Thus, our data highlight a novel role for ALKBH3 in tumor progression via RNA demethylation and subsequent protein synthesis promotion.

MiR-21-5p in urinary extracellular vesicles is a novel biomarker of urothelial carcinoma

Background Extracellular vesicles are lipid bilayer vesicles containing protein, messengerRNA and microRNA. Cancer cell-derived extracellular vesicles may be diagnostic and therapeutic targets. We extracted extracellular vesicles from urine of urothelial carcinoma patients and the control group to identify cancer-specific microRNAs in urinary extracellular vesicles as new biomarkers. Materials and methods microRNA from urinary extracellular vesicles extracted from 6 urothelial carcinoma patients and 3 healthy volunteers was analyzed. We verified candidate microRNAs in an independent cohort of 60 urinary extracellular vesicles samples. To normalize the microRNA expression level in extracellular vesicles, we examined the following in extracellular vesicles: protein concentration, CD9 intensity, amounts of whole miRNAs, RNA U6B small nuclear expression and the creatinine concentration of original urine correlating with the counts of extracted extracellular vesicles measured by the NanoSight™ system. RESULTS From the microarray results 5 microRNAs overexpressed in urinary extracellular vesicles of urothelial carcinoma patients were identified. Creatinine concentration of original urine correlated most with particle counts of extracellular vesicles, indicating that creatinine could be a new tool for normalizing microRNA expression. MiR-21-5p was the most potent biomarker in urinary extracellular vesicles (sensitivity, 75.0%; specificity, 95.8%) and was also overexpressed in urinary extracellular vesicles from urothelial carcinoma patients with negative urine cytology. For the subgroup with negative urine cytology, the sensitivity was 75.0% and specificity was 95.8%. Conclusion MiR-21-5p in urinary extracellular vesicles could be a new biomarker of urothelial carcinoma, especially for urothelial carcinoma patients with negative urine cytology.

LOXL2 Status Correlates with Tumor Stage and Regulates Integrin Levels to Promote Tumor Progression in ccRCC

Clear cell renal cell carcinoma (ccRCC) is the most common histologically defined subtype of renal cell carcinoma (RCC). To define the molecular mechanism in the progression of ccRCC, we focused on LOX-like protein 2 (LOXL2), which is critical for the first step in collagen and elastin cross-linking. Using exon array analysis and quantitative validation, LOXL2 was shown to be significantly upregulated in clinical specimens of human ccRCC tumor tissues, compared with adjacent noncancerous renal tissues, and this elevated expression correlated with the pathologic stages of ccRCC. RNAi-mediated knockdown of LOXL2 resulted in marked suppression of stress-fiber and focal adhesion formation in ccRCC cells. Moreover, LOXL2 siRNA knockdown significantly inhibited cell growth, migration, and invasion. Mechanistically, LOXL2 regulated the degradation of both integrins α5 (ITGAV5) and β1 (ITGB1) via protease- and proteasome-dependent systems. In clinical ccRCC specimens, the expression levels of LOXL2 and integrin α5 correlated with the pathologic tumor grades. In conclusion, LOXL2 is a potent regulator of integrin α5 and integrin β1 protein levels and functions in a tumor-promoting capacity in ccRCC. Implications: This is the first report demonstrating that LOXL2 is highly expressed and involved in ccRCC progression by regulating the levels of integrins α5 and β1. Mol Cancer Res; 12(12); 1807–17. ©2014 AACR.

Extracellular vesicles isolated from human renal cell carcinoma tissues disrupt vascular endothelial cell morphology via azurocidin

Cancer‐associated extracellular vesicles (EVs) are intimately involved in establishment of tumor microenvironment and occurrence of metastasis. However, previous studies have mainly relied on experiments with cultured cell lines or mouse models, making it difficult to gain a full understanding of EV functions in human body. Hence, we extracted EVs directly from surgically resected viable clear cell renal cell carcinoma (ccRCC) tissues and adjacent normal renal tissues (nu2009=u200920). Quantitative LC/MS analysis identified 3,871 tissue‐exudative EV (Te‐EV) proteins, among which azurocidin (AZU1) was highly enriched in tumor Te‐EVs (pu2009=u20092.85 × 10−3, fold‐changeu2009=u200931.59). Importantly, AZU1 content was also significantly higher in serum EVs from ccRCC patients compared to those from healthy donors. We further found that ccRCC‐derived EVs had AZU1‐dependent membrane permeabilizing activity for the vascular endothelial cell layer. Thus Te‐EVs should be ideal resource for investigation of physiological EV functions.

High-Fat Diet-Induced Inflammation Accelerates Prostate Cancer Growth via IL6 Signaling

Purpose: High-fat diet (HFD) could induce prostate cancer progression. The aim of this study is to identify mechanisms of HFD-induced prostate cancer progression, focusing on inflammation. Experimental Design: We administered HFD and celecoxib to autochthonous immunocompetent Pb-Cre+;Pten(fl/fl) model mice for prostate cancer. Tumor growth was evaluated by tumor weight and Ki67 stain, and local immune cells were assessed by flow cytometry at 22 weeks of age. Cytokines which correlated with tumor growth were identified, and the changes of tumor growth and local immune cells after inhibition of the cytokine signals were evaluated in the mice. IHC analyses using prostatectomy specimens of obese patients were performed. Results: HFD accelerated tumor growth and increased the myeloid-derived suppressor cells (MDSCs) fraction and M2/M1 macrophage ratio in the model mice. Celecoxib-suppressed tumor growth, and decreased both local MDSCs and M2/M1 macrophage ratio in HFD-fed mice. HFD-induced tumor growth was associated with IL6 secreted by prostatic macrophages, as were phosphorylated STAT3 (pSTAT3)-positive tumor cells. Anti-IL6 receptor antibody administration suppressed tumor growth, and decreased local MDSCs and pSTAT3-positive cell fractions in HFD-fed mice. The tumor-infiltrating CD11b-positive cell count was significantly higher in prostatectomy specimens of obese than those of nonobese patients with prostate cancer. Conclusions: HFD increased MDSCs and accelerated prostate cancer tumor growth via IL6/pSTAT3 signaling in the mice. This mechanism could exist in obese patients with prostate cancer. IL6-mediated inflammation could be a therapeutic target for prostate cancer. Clin Cancer Res; 24(17); 4309–18. ©2018 AACR.

Peripheral blood monocyte count reflecting tumor-infiltrating macrophages is a predictive factor of adverse pathology in radical prostatectomy specimens.

Tumor‐infiltrating macrophages, which are thought to be derived from blood monocytes, interact with tumor cells to promote cancer progression. The aim of this study was to assess the association of peripheral blood monocyte count with pathological findings and local tumor‐infiltrating macrophages in prostatectomy specimens.

Expression level of CXCL7 in peripheral blood cells is a potential biomarker for the diagnosis of renal cell carcinoma

There are no blood biomarkers for the diagnosis of renal cell carcinoma (RCC) in routine clinical use. We focused on the gene expression profile of peripheral blood cells obtained from RCC patients to discover novel biomarkers for RCC diagnosis. Using microarray analysis and quantitative verification, CXCL7 was shown to be significantly upregulated in the peripheral blood cells of RCC patients. Importantly, aberrant CXCL7 expression was confirmed even in peripheral blood cells obtained from early stage (pT1a) RCC patients, and the expression level of CXCL7 in peripheral blood cells was a potential independent biomarker for the diagnosis of RCC by receiver operating characteristic curve analysis (sensitivity, 70.0%; specificity, 64.0%; area under the curve = 0.722; multiple logistic regression analysis: odds ratio, 1.07; 95% confidence interval, 1.03–1.11; P = 0.0004). Moreover, CXCL7 expression in peripheral blood cells significantly decreased after resection of the primary tumor. CXCL7 is more highly expressed in PBMCs than in neutrophils from both healthy controls and RCC patients. Interestingly, CXCL7 expression in PBMCs from healthy volunteers was significantly elevated following coculture with RCC cells compared to those cocultured with normal cells as a control. These results suggest that aberrant CXCL7 expression in peripheral blood cells is induced by RCC cells and may serve as a novel biomarker in the diagnosis of RCC.

TP53 gene status is a critical determinant of phenotypes induced by ALKBH3 knockdown in non-small cell lung cancers

Human AlkB homolog 3 (ALKBH3) is overexpressed in non-small cell lung cancers (NSCLC) and its high expression is significantly correlated with poor prognosis. While ALKBH3 knockdown induces apoptosis in NSCLC cells, the underlying anti-apoptotic mechanisms of ALKBH3 in NSCLC cells remain unclear. Here we show that ALKBH3 knockdown induces cell cycle arrest or apoptosis depending on the TP53 gene status in NSCLC cells. In comparison to parental cells, TP53-knockout A549xa0cells showed DNA damage-responsive signal induced by ALKBH3 knockdown. TP53 knockout shifted the phenotypes of A549xa0cells induced by ALKBH3 knockdown from cell cycle arrest to apoptosis induction, suggesting that the TP53 gene status is a critical determinant of the phenotypes induced by ALKBH3 knockdown in NSCLC cells.