Ryosuke Matsushita

Tumor‐suppressive microRNA‐223 inhibits cancer cell migration and invasion by targeting ITGA3/ITGB1 signaling in prostate cancer

Analysis of microRNA (miRNA) expression signatures in prostate cancer (PCa) and castration‐resistant PCa has revealed that miRNA‐223 is significantly downregulated in cancer tissues, suggesting that miR‐223 acts as a tumor‐suppressive miRNA by targeting oncogenes. The aim of this study was to investigate the functional roles of miR‐223 and identify downstream oncogenic targets regulated by miR‐223 in PCa cells. Functional studies of miR‐223 were carried out to investigate cell proliferation, migration, and invasion using PC3 and PC3M PCa cell lines. Restoration of miR‐223 significantly inhibited cancer cell migration and invasion in PCa cells. In silico database and genome‐wide gene expression analyses revealed that ITGA3 and ITGB1 were direct targets of miR‐223 regulation. Knockdown of ITGA3 and ITGB1 significantly inhibited cancer cell migration and invasion in PCa cells by regulating downstream signaling. Moreover, overexpression of ITGA3 and ITGB1 was observed in PCa clinical specimens. Thus, our data indicated that downregulation of miR‐223 enhanced ITGA3/ITGB1 signaling and contributed to cancer cell migration and invasion in PCa cells. Elucidation of the molecular pathways modulated by tumor‐suppressive miRNAs provides insights into the mechanisms of PCa progression and metastasis.

MicroRNA expression signature of castration-resistant prostate cancer: the microRNA-221/222 cluster functions as a tumour suppressor and disease progression marker

Background:Our present study of the microRNA (miRNA) expression signature in castration-resistant prostate cancer (CRPC) revealed that the clustered miRNAs microRNA-221 (miR-221) and microRNA-222 (miR-222) are significantly downregulated in cancer tissues. The aim of this study was to investigate the functional roles of miR-221 and miR-222 in prostate cancer (PCa) cells.Methods:A CRPC miRNA signature was constructed by PCR-based array methods. Functional studies of differentially expressed miRNAs were analysed using PCa cells. The association between miRNA expression and overall survival was estimated by the Kaplan–Meier method. In silico database and genome-wide gene expression analyses were performed to identify molecular targets regulated by the miR-221/222 cluster.Results:miR-221 and miR-222 were significantly downregulated in PCa and CRPC specimens. Kaplan–Meier survival curves showed that low expression of miR-222 predicted a short duration of progression to CRPC. Restoration of miR-221 or miR-222 in cancer cells revealed that both miRNAs significantly inhibited cancer cell migration and invasion. Ecm29 was directly regulated by the miR-221/222 cluster in PCa cells.Conclusions:Loss of the tumour-suppressive miR-221/222 cluster enhanced migration and invasion in PCa cells. Our data describing targets regulated by the tumour-suppressive miR-221/222 cluster provide insights into the mechanisms of PCa and CRPC progression.

Downregulation of the microRNA-1/133a cluster enhances cancer cell migration and invasion in lung-squamous cell carcinoma via regulation of Coronin1C

Lung cancer is clearly the primary cause of cancer-related deaths worldwide. Recent molecular-targeted strategy has contributed to improvement of the curative effect of adenocarcinoma of the lung. However, such current treatment has not been developed for squamous cell carcinoma (SCC) of the disease. The new genome-wide RNA analysis of lung-SCC may provide new avenues for research and the development of the disease. Our recent microRNA (miRNA) expression signatures of lung-SCC revealed that clustered miRNAs miR-1/133a were significantly reduced in cancer tissues. Here, we found that restoration of both mature miR-1 and miR-133a significantly inhibited cancer cell proliferation, migration and invasion. Coronin-1C (CORO1C) was a common target gene of the miR-1/133a cluster, as shown by the genome-wide gene expression analysis and the luciferase reporter assay. Silencing of CORO1C gene expression inhibited cancer cell proliferation, migration and invasion. Furthermore, CORO1C-regulated molecular pathways were categorized by using si-CORO1C transfectants. Further analysis of novel cancer signaling pathways modulated by the tumor-suppressive cluster miR-1/133a will provide insights into the molecular mechanisms of lung-SCC oncogenesis and metastasis.

Tumour-suppressive microRNA-29s directly regulate LOXL2 expression and inhibit cancer cell migration and invasion in renal cell carcinoma

Here, we found that members of the microRNA‐29 family (miR‐29a/b/c; “miR‐29s”) were significantly reduced in clear cell renal cell carcinoma (ccRCC) tissues, suggesting that they functioned as tumour suppressors. Restoration of all mature members of the miR‐29 family inhibited cancer cell proliferation, migration and invasion. LOXL2 was a direct target gene of miR‐29s, as shown by genome‐wide gene expression analysis and luciferase reporter assay. Overexpressed LOXL2 was confirmed in ccRCC clinical specimens, and silencing of LOXL2 inhibited cancer cell migration and invasion in ccRCC cell lines. Our data demonstrated that the miR‐29s‐LOXL2 axis contributed to cancer cell migration and invasion in ccRCC.

The microRNA signature of patients with sunitinib failure: regulation of UHRF1 pathways by microRNA-101 in renal cell carcinoma.

Molecular targeted therapy is a standard treatment for patients with advanced renal cell carcinoma (RCC). Sunitinib is one of the most common molecular-targeted drugs for metastatic RCC. Molecular mechanisms of sunitinib resistance in RCC cells is still ambiguous. The microRNA (miRNA) expression signature of patients with sunitinib failure in RCC was constructed using a polymerase chain reaction (PCR)-based array. Several miRNAs that were aberrantly expressed in RCC tissues from patients treated with sunitinib were identified in this analysis. MicroRNA-101 (miR- 101) was markedly suppressed in sunitinib treated RCC tissues. Restoration of miR-101 significantly inhibited cell migration and invasion in Caki-1 and 786-O cells. Ubiquitin-like with PHD and ring finger domains 1 (UHRF1) was directly suppressed by miR-101 in RCC cells, and overexpression of UHRF1 was confirmed in sunitinib-treated RCC tissues. The pathways of nucleotide excision repair and mismatch repair were significantly suppressed by knockdown of UHRF1. Our findings showed that antitumor miR-101- mediated UHRF1 pathways may be suppressed by sunitinib treatment.

Regulation of the collagen cross-linking enzymes LOXL2 and PLOD2 by tumor-suppressive microRNA-26a/b in renal cell carcinoma

Our recent studies of microRNA (miRNA) expression signatures in human cancers revealed that microRNA-26a (miRNA-26a) and microRNA-26b (miRNA-26b) were significantly reduced in cancer tissues. To date, few reports have provided functional analyses of miR-26a or miR-26b in renal cell carcinoma (RCC). The aim of the present study was to investigate the functional significance of miR-26a and miR-26b in RCC and to identify novel miR-26a/b-mediated cancer pathways and target genes involved in RCC oncogenesis and metastasis. Downregulation of miR-26a or miR-26b was confirmed in RCC clinical specimens. Restoration of miR-26a or miR-26b in RCC cell lines (786-O and A498) revealed that these miRNAs significantly inhibited cancer cell migration and invasion. Our in silico analysis and luciferase reporter assays showed that lysyl oxidase-like 2 (LOXL2) and procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2) were directly regulated by these miRNAs. Moreover, downregulating the PLOD2 gene significantly inhibited cell migration and invasion in RCC cells. Thus, our data showed that two genes promoting metastasis, LOXL2 and PLOD2, were epigenetically regulated by tumor-suppressive microRNAs, miR-26a and miR-26b, providing important insights into the molecular mechanisms of RCC metastasis.

Tumor-suppressive microRNA-29 family inhibits cancer cell migration and invasion directly targeting LOXL2 in lung squamous cell carcinoma

Lung cancer remains the most frequent cause of cancer-related death in developed countries. A recent molecular-targeted strategy has contributed to improvement of the remarkable effect of adenocarcinoma of the lung. However, such treatment has not been developed for squamous cell carcinoma (SCC) of the disease. Our recent studies of microRNA (miRNA) expression signatures of human cancers showed that the microRNA-29 family (miR-29a, miR-29b and miR-29c) significantly reduced cancer tissues compared to normal tissues. These findings suggest that miR-29s act as tumor-suppressors by targeting several oncogenic genes. The aim of the study was to investigate the functional significance of miR-29s in lung SCC and to identify miR-29s modulating molecular targets in lung SCC cells. Restoration of all mature members of the miR-29s inhibited cancer cell migration and invasion. Gene expression data combined in silico analysis and luciferase reporter assays demonstrated that the lysyl oxidase-like 2 (LOXL2) gene was a direct regulator of tumor-suppressive miR-29s. Moreover, overexpressed LOXL2 was confirmed in lung SCC clinical specimens, and silencing of LOXL2 inhibited cancer cell migration and invasion in lung SCC cell lines. Our present data suggested that loss of tumor-suppressive miR-29s enhanced cancer cell invasion in lung SCC through direct regulation of oncogenic LOXL2. Elucidation of the novel lung SCC molecular pathways and targets regulated by tumor-suppressive miR-29s will provide new insights into the potential mechanisms of oncogenesis and metastasis of the disease.

Tumor-suppressive microRNAs (miR-26a/b, miR-29a/b/c and miR-218) concertedly suppressed metastasis-promoting LOXL2 in head and neck squamous cell carcinoma

In spite of considerable advances in multimodality therapy, including surgery, radiotherapy and chemotherapy, the overall survival rate for patients with head and neck squamous cell carcinoma (HNSCC) is very poor (only 15–45%). Understanding the molecular mechanisms of metastatic pathways underlying HNSCC using currently available genomic approaches might improve therapies for and prevention of the disease. Our previous studies showed that three tumor-suppressive microRNAs (miRNAs), miR-26a/b, miR-29a/b/c and miR-218, significantly inhibited cancer cell migration and invasion. Therefore, we hypothesized that these miRNAs-regulated target genes deeply contributed to cancer metastasis. These tumor-suppressive miRNAs directly regulate LOXL2 expression in HNSCC cells by using in silico analysis and luciferase reporter assays. Overexpressed LOXL2 was confirmed in HNSCC clinical specimens, and silencing of LOXL2 inhibited cancer cell migration and invasion in HNSCC cell lines. Our present data showed that tumor-suppressive miRNAs regulation of LOXL2 will provide new insights into the novel molecular mechanisms of HNSCC metastasis.

Direct regulation of LAMP1 by tumor-suppressive microRNA-320a in prostate cancer

Advanced prostate cancer (PCa) metastasizes to bone and lymph nodes, and currently available treatments cannot prevent the progression and metastasis of the disease. Therefore, an improved understanding of the molecular mechanisms of the progression and metastasis of advanced PCa using current genomic approaches is needed. Our miRNA expression signature in castration-resistant prostate cancer (CRPC) revealed that microRNA-320a (miR-320a) was significantly reduced in cancer tissues, suggesting that miR-320a may be a promising anticancer miRNA. The aim of this study was to investigate the functional roles of miR-320a in naïve PCa and CRPC cells and to identify miR-320a-regulated genes involved in PCa metastasis. The expression levels of miR-320a were significantly reduced in naïve PCa, CRPC specimens, and PCa cell lines. Restoration of mature miR-320a in PCa cell lines showed that miR-320a significantly inhibited cancer cell migration and invasion. Moreover, we found that lysosomal-associated membrane protein 1 (LAMP1) was a direct target of miR-320a in PCa cells. Silencing of LAMP1 using siRNA significantly inhibited cell proliferation, migration, and invasion in PCa cells. Overexpression of LAMP1 was observed in PCa and CRPC clinical specimens. Moreover, downstream pathways were identified using si-LAMP1-transfected cells. The discovery of tumor-suppressive miR-320a-mediated pathways may provide important insights into the potential mechanisms of PCa metastasis.

MicroRNA-205 inhibits cancer cell migration and invasion via modulation of centromere protein F regulating pathways in prostate cancer.

To investigate the functional roles of microRNA‐205 in the modulation of novel cancer pathways in prostate cancer cells.