Protein Regulator Of Cytokinesis 1 Expression Research Articles

Protein regulator of cytokinesis 1 accentuates cholangiocarcinoma progression via mTORC1-mediated glycolysis.

This study aimed to investigate the expression of protein regulator of cytokinesis 1 (PRC1) in cholangiocarcinoma (CHOL) and elucidate its potential impact as well as the underlying mechanisms governing the progression of CHOL. In this study, we used CHOL cells (HUCCT1, RBE, and CCLP1) and conducted a series of experiments, including qRT-PCR, cell counting kit-8 assays, EdU assays, flow cytometry, wound healing assays, Transwell assays, western blotting, double luciferase assays, and ELISA. Subsequently, a mouse model was established using cancer cell injections. Haematoxylin-eosin staining, along with Ki67 and TUNEL assays, were employed to assess tissue histopathology, cell proliferation, and apoptosis. Our findings revealed significantly elevated PRC1 expression in CHOL. According to bioinformatics analysis, it was found that the increased PRC1 level is correlated with the high tumour grades, metastases, and unfavourable prognoses. Notably, PRC1 knockdown inhibited cell viability, proliferation, migration, and invasion while promoting apoptosis in CHOL cells. Analysing TCGA-CHOL data and utilising transcription factor prediction tools (hTFtarget and HumanTFDB), we identified that genes positively correlated with PRC1 in TCGA-CHOL intersect with predicted transcription factors, revealing the activation of PRC1 by forkhead box protein M1 (FOXM1). Moreover, PRC1 was found to exert regulatory control over glycolysis and the mammalian target of rapamycin complex 1 (mTORC1) pathway in the context of CHOL based on KEGG and GSEA analysis. Collectively, these results underscore the pivotal role of PRC1 in CHOL progression, wherein it modulates glycolysis and the mTORC1 pathway under the regulatory influence of FOXM1.

PRC1 plays an important role in lung adenocarcinoma and is potentially targeted by fostamatinib.

Lung adenocarcinoma (LUAD) is one of the most common cancers in the world. Protein regulator of cytokinesis 1 (PRC1) plays a role in the tumorigenesis and development of several cancers, including LUAD. The aim of the present study is to assess the characteristics of PRC1 in LUAD in order to find a potential drug that targets PRC1. We investigated the prognostic value of PRC1 in patients with LUAD using Cox analysis of the RNA sequencing data from The Cancer Genome Atlas (TCGA) portal. A link between PRC1 and LUAD progression, cigarette smoking mutation count, aneuploidy, and hypoxia scores was assessed. The relationship between PRC1 and tumor-infiltrating immune cells in LUAD was analyzed and Gene Set Enrichment Analysis (GSEA) was used to study the PRC1-related biological process and signal pathways. Potential drugs targeting PRC1 were identified using DrugBank database and molecular docking. PRC1 expression was significantly increased in LUAD. PRC1 could be, therefore, a prognostic biomarker for predicting overall survival in LUAD. PRC1 expression was also related to cancer stage and patient's smoking history. PRC1 positively correlated with mutation count, aneuploidy and hypoxia scores. It was also significantly related to tumor-infiltrating immune cells, especially the activated mast cells. GSEA revealed that PRC1 might be correlated with cell cycle, cytokinesis and p53 signaling pathway. Additionally, fostamatinib was found to be a potential drug targeting PRC1. PRC1 may have a prognostic value for patients with LUAD, and be correlated with the mutation count, aneuploidy, hypoxia and tumor-infiltrating immune cells. Fostamatinib was found to be a potential drug targeting PRC1 in LUAD.

Expression of the cytokinesis regulator PRC1 results in p53-pathway activation in A549 cells but does not directly regulate gene expression in the nucleus

ABSTRACT Protein regulator of cytokinesis 1 (PRC1) is a microtubule-binding protein with essential roles in mitosis and cytokinesis. PRC1 is frequently overexpressed in cancer cells where it could contribute to chromosomal instability. Due to its nuclear localization in interphase, it has been speculated that PRC1 has additional functions that are involved in its pro-tumorigenic functions. In this study we investigated the potential nuclear functions of PRC1 in a lung cancer cell line. Genome wide expression profiling by RNA sequencing revealed that the expression of PRC1 results in activation of the p53 pathway and inhibition of the pro-proliferative E2F-dependent gene expression. A mutant of PRC1 that is unable to enter into the nucleus regulated the same gene sets as wildtype PRC1, suggesting that PRC1 has no nuclear-exclusive functions in A549 cells. Instead, induction of p53 by PRC1 correlates with multinucleation and depends on the localization of PRC1 to the midbody, suggesting that the induction of p53 is a consequence of overexpressed PRC1 to interfere with the normal function of PRC1 during cytokinesis. Activation of p53 by PRC1 results in cellular senescence but not in apoptosis. In conclusion, while PRC1 is frequently overexpressed in many cancers, the p53 pathways may initially protect cancer cells from the negative effects of PRC1 overexpression on cytokinesis. Because depletion of PRC1 also results in p53-pathway activation and senescence, levels of PRC1 need to be tightly regulated to allow unperturbed proliferation. Targeting the expression or function of PRC1 could create a therapeutic vulnerability for the treatment of cancer.

Protein Regulator of Cytokinesis 1 (PRC1) Upregulation Promotes Immune Suppression in Liver Hepatocellular Carcinoma.

Liver hepatocellular carcinoma (LIHC) is a malignant cancer with widespread prevalence. The suppressive immune environment causes largely refractory to current treatment. The protein regulator of cytokinesis 1 (PRC1) is an essential gene for cytokinesis and is involved in cancer pathogenesis. However, the functions of PRC1 have been barely clarified, especially in LIHC. Here, we investigated the expression, prognostic value, and functions of PRC1 in LIHC. Pan-cancer analysis revealed the overexpression of PRC1 in the Cancer Genome Atlas (TCGA) database. Four LIHC datasets from the Gene Expression Omnibus (GEO) database confirmed the PRC1 overexpression in LIHC. The mRNA and protein levels of PRC1 in LIHC cells were higher than in normal liver cells. The overexpression of PRC1 predicted progressed clinical stage and poor prognosis of LIHC. We further investigated the functions of PRC1 by performing the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, and Gene Set Enrichment Analysis (GSEA) of its coexpressing genes. High PRC1 expression was associated with increased genome instability of LIHC. Moreover, PRC1 was positively correlated with the infiltration of suppressive immune cells like T regulatory cells (Tregs) and polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) and was negatively correlated with the effector immune cells' infiltration, including B cells and CD8+ T cells. In addition, PRC1 was positively correlated with the expression of tumor immune checkpoint molecules. Taken together, PRC1 overexpression contributes to the genome instability and the suppressive immune microenvironment of LIHC. Thus, PRC1 has the potential to be a prognostic marker and therapeutic target of LIHC.

Therapeutic targeting of the PLK1-PRC1-axis triggers cell death in genomically silent childhood cancer

Chromosomal instability (CIN) is a hallmark of cancer1. Yet, many childhood cancers, such as Ewing sarcoma (EwS), feature remarkably ‘silent’ genomes with minimal CIN2. Here, we show in the EwS model how uncoupling of mitosis and cytokinesis via targeting protein regulator of cytokinesis 1 (PRC1) or its activating polo-like kinase 1 (PLK1) can be employed to induce fatal genomic instability and tumor regression. We find that the EwS-specific oncogenic transcription factor EWSR1-FLI1 hijacks PRC1, which physiologically safeguards controlled cell division, through binding to a proximal enhancer-like GGAA-microsatellite, thereby promoting tumor growth and poor clinical outcome. Via integration of transcriptome-profiling and functional in vitro and in vivo experiments including CRISPR-mediated enhancer editing, we discover that high PRC1 expression creates a therapeutic vulnerability toward PLK1 inhibition that can repress even chemo-resistant EwS cells by triggering mitotic catastrophe.Collectively, our results exemplify how aberrant PRC1 activation by a dominant oncogene can confer malignancy but provide opportunities for targeted therapy, and identify PRC1 expression as an important determinant to predict the efficacy of PLK1 inhibitors being used in clinical trials.

Analysis of transcriptome in the relationship between expression of PRC1 protein and prognosis of patients with cholangiocarcinoma.

ObjectiveTo investigate whether protein regulator of cytokinesis 1 (PRC1), which is involved in the regulation of human carcinogenesis, contributes to poor prognosis in patients with cholangiocarcinoma (CCA).MethodsData and tissues from patients with CCA were retrospectively studied. Immunohistochemical staining and western blotting were used to evaluate and contrast the PRC1 expression profile at the protein level in CCA tumour and pericarcinomatous tissues from the same study population. Relationships between clinical characteristics and patient survival were observed using univariate and multivariate analyses. Correlations between PRC1 expression and clinical characteristics were analysed by logistic regression.ResultsA total of 45 patients were included. PRC1 expression was found to be upregulated in CCA cancer tissues versus pericarcinomatous tissues. Overexpression of PRC1 was shown to be related to tumour differentiation, tumour node metastasis staging and lymph node metastasis, and was also revealed to be an independent marker of poor CCA prognosis.ConclusionsThe present results suggest that PRC1 may be a prognostic and therapeutic biomarker for patients with CCA.

MicroRNA-194 inhibits PRC1 activation of the Wnt/β-catenin signaling pathway to prevent tumorigenesis by elevating self-renewal of non-side population cells and side population cells in esophageal cancer stem cells.

Esophageal cancer (EC) is a leading cause of cancer-related deaths worldwide. Recent studies highlight roles for microRNAs (miRNAs) in EC. Microarray analysis identified miR-194 as downregulated in EC. However, little is known about the role of miR-194 in regulating self-renewal or other biological properties of EC stem cells. RT-qPCR and Western blot confirmed the downregulation of miR-194 in EC stem cells and revealed the upregulation of protein regulator of cytokinesis 1 (PRC1) in EC. Dual-luciferase reporter assay confirmed miR-194 targeting of PRC1 resulting in its downregulation. MiR-194 overexpression or PRC1 silencing reduced PRC1 expression, preventing the activation of the Wnt/β-catenin signaling pathway. Inhibition of the Wnt/β-catenin signaling pathway prevented the proliferation, invasion, and self-renewal of EC stem cells while promoting apoptosis. Furthermore, overexpressing miR-194 or silencing PRC1 in nude mice decreased the tumor formation ability of EC stem cells in vivo. Taken together, miR-194 prevents the progression of EC by downregulating PRC1 and inactivating the Wnt/β-catenin signaling pathway.

Protein regulator of cytokinesis 1 regulates chromosome dynamics and cytoplasmic division during mouse oocyte meiotic maturation and early embryonic development.

In contrast to the homeokinesis of mitosis, asymmetric division of cytoplasm is the conspicuous feature of meiosis in mammalian oocytes. Protein regulator of cytokinesis 1 (PRC1) is an important regulator during mitotic spindle assembly and cytoplasmic division, but its functions in oocyte meiosis and early embryo development have not been fully elucidated. In this study, we detected PRC1 expression and localization and revealed a nuclear, spindle midzone-related dynamic pattern throughout meiotic and mitotic progressions. Treatment of oocytes with the reagents taxol or nocodazole disturbed the distribution of PRC1 in metaphase II oocytes. Further, PRC1 depletion led to failure of first polar body (PB1) extrusion and spindle migration, aneuploidy and defective kinetochore-microtubule attachment and spindle assembly. Overexpression of PRC1 resulted in PB1 extrusion failure, aneuploidy and serious defects of spindle assembly. To investigate PRC1 function in early embryos, we injected Prc1 morpholino into zygotes and 2-cell stage embryos. Depletion of PRC1 in zygotes impaired 4-cell, morula and blastocyst formation. Loss of PRC1 in single or double blastomeres in 2-cell stage embryos significantly impaired cell division, indicating its indispensable role in early embryo development. Co-immunoprecipitation showed that PRC1 interacts with polo-like kinase 1 (PLK1), and functional knockdown and rescue experiments demonstrated that PRC1 recruits PLK1 to the spindle midzone to regulate cytoplasmic division during meiosis. Finally, kinesin family member 4 knockdown downregulates PRC1 expression and leads to PRC1 localization failure. Taken together, our data suggest PRC1 plays an important role during oocyte maturation and early embryonic development by regulating chromosome dynamics and cytoplasmic division.

PRC1 is a critical regulator for anaphase spindle midzone assembly and cytokinesis in mouse oocyte meiosis.

Protein regulator of cytokinesis 1 (PRC1) is a microtubule bundling protein that is involved in the regulation of the central spindle bundle and spindle orientation during mitosis. However, the functions of PRC1 during meiosis have rarely been studied. In this study, we explored the roles of PRC1 during meiosis using an oocyte model. Our results found that PRC1 was expressed at all stages of mouse oocyte meiosis, and PRC1 accumulated in the midzone/midbody during anaphase/telophase I. Moreover, depleting PRC1 caused defects in polar body extrusion during mouse oocyte maturation. Further analysis found that PRC1 knockdown did not affect meiotic spindle formation or chromosome segregation; however, deleting PRC1 prevented formation of the midzone and midbody at the anaphase/telophase stage of meiosis I, which caused cytokinesis defects and further induced the formation of two spindles in the oocytes. PRC1 knockdown increased the level of tubulin acetylation, indicating that microtubule stability was affected. Furthermore, KIF4A and PRC1 showed similar localization in the midzone/midbody of oocytes at anaphase/telophase I, while the depletion of KIF4A affected the expression and localization of PRC1. The PRC1 mRNA injection rescued the defects caused by PRC1 knockdown in oocytes. In summary, our results suggest that PRC1 is critical for midzone/midbody formation and cytokinesis under regulation of KIF4A in mouse oocytes.

RETRACTED: Overexpression of microRNA-203 Suppresses Proliferation, Invasion, and Migration while Accelerating Apoptosis of CSCC Cell Line SCL-1

Cutaneous squamous cell carcinoma (CSCC) is a malignant proliferation of cutaneous epithelium that has been observed to have an alarming rise in incidence. Numerous studies have demonstrated microRNAs (miRNAs or miRs) as important biomarkers in the diagnosis, prognosis, and treatment of CSCC. This study aims to investigate the effects of miR-203 on the behaviors of CSCC cells and possible mechanisms associated with protein regulator of cytokinesis-1 (PRC1) and Wnt/β-catenin signaling pathway. PRC1 was suggested as a target of miR-203 in squamous cell carcinoma cell line 1 (SCL-1) cells by dual-luciferase reporter gene assay. Based on the immunohistochemical staining and qRT-PCR, PRC1 was abundantly expressed while miR-203 was poorly expressed in CSCC tissues. miR-203 mimic or inhibitor was transfected into SCL-1 cells to upregulate or downregulate its expression. Upregulation of miR-203 downregulated PRC1 expression to block the Wnt/β-catenin signaling pathway. By conducting 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), scratch test, and Transwell and flow cytometric analyses, miR-203 was witnessed to restrain SCL-1 cell proliferation, migration, and invasion while accelerating their apoptosis. The rescue experiments addressed that inhibition of the Wnt/β-catenin signaling pathway conferred the anti-tumor effect of miR-203. These results establish a tumor-suppressive role for miR-203 in CSCC cell line SCL-1. Hence, miR-203 has promising potential as a therapeutic target for CSCC.

Overexpression of PRC1 indicates a poor prognosis in ovarian cancer

Protein regulator of cytokinesis-1 (PRC1) is a microtubule-associated factor involved in cytokinesis. Recent studies have indicated that PRC1 overexpression is involved in tumorigenesis in multiple types of human cancer. However, the expression, biological functions and the prognostic significance of PRC1 in ovarian cancer have not yet been clarified. In this study, it was confirmed that the PRC1 mRNA and protein expression levels were upregulated in high-grade serous ovarian carcinoma (HGSOC) tissues, particularly in patients without breast cancer susceptibility gene (BRCA) pathogenic mutations. PRC1 overexpression contributed to drug resistance, tumor recurrence and a poor prognosis. The findings also indicated that PRC1 knockdown decreased the proliferation, metastasis and multidrug resistance of ovarian cancer cells in vitro. It was also demonstrated that forkhead box protein M1 (FOXM1) regulated the mRNA and protein expression of PRC1. Dual-luciferase reporter assay and rescue assay confirmed that PRC1 was a direct crucial downstream target of FOXM1. On the whole, the findings of this study confirmed that PRC1 was a major prognostic factor of HGSOC and a promising therapeutic biomarker for the treatment of ovarian cancer.

PRC1 promotes cell proliferation and cell cycle progression by regulating p21/p27-pRB family molecules and FAK-paxillin pathway in non-small cell lung cancer

Background: This study aimed to demonstrate the function and molecular mechanism of protein regulator of cytokinesis 1 ( PRC1 ) in the carcinogenesis of non-small cell lung cancer (NSCLC). Methods: Bioinformatics analysis was performed. Cell culture and plasmid construction were conducted for cell transfection. mRNA and protein expression, cell proliferation, migration, and cell cycle were detected. Mice models were also constructed. The relationship between PRC1 and the prognosis of NSCLC patients was analyzed. Results: PRC1 expression was higher in tumor tissues than adjacent non-tumor tissues (P PRC1 expression were more likely to have lymph node metastasis occur (P Kip1/p27 (P Conclusions: PRC1 could promote cell proliferation and cell cycle progression through FAK-paxillin pathway molecules and the regulation of the phosphorylation level of p21/p27-pRB family molecules. PRC1 might be a new and promising therapeutic target for NSCLC.

PRC1 promotes cell proliferation and cell cycle progression by regulating p21/p27-pRB family molecules and FAK-paxillin pathway in non-small cell lung cancer.

BackgroundThis study aimed to demonstrate the function and molecular mechanism of protein regulator of cytokinesis 1 (PRC1) in the carcinogenesis of non-small cell lung cancer (NSCLC).MethodsBioinformatics analysis was performed. Cell culture and plasmid construction were conducted for cell transfection. mRNA and protein expression, cell proliferation, migration, and cell cycle were detected. Mice models were also constructed. The relationship between PRC1 and the prognosis of NSCLC patients was analyzed.ResultsPRC1 expression was higher in tumor tissues than adjacent non-tumor tissues (P<0.05). Cells transfected with the high-expression PRC1 plasmid (TOPO-PRC1 group) had the stronger ability of proliferation and migration (P<0.05) along with a lower incidence of stay at the G2/M phase (P<0.05) than the low-expression PRC1 plasmid. Mice models showed tumors obtained from mice in the TOPO-PRC1 group significantly grew faster, larger, and heavier (P<0.05) than the low-expression PRC1 group. Among the 150 NSCLC patients, patients with the higher PRC1 expression were more likely to have lymph node metastasis occur (P<0.05) and progress into an advanced stage (P<0.05), and showed shorter survival (P<0.05). Moreover, the TOPO-PRC1 group had a lower phosphorylation level, and a lower expression of Cip1/p21 (P<0.05) and Kip1/p27 (P<0.01).ConclusionsPRC1 could promote cell proliferation and cell cycle progression through FAK-paxillin pathway molecules and the regulation of the phosphorylation level of p21/p27-pRB family molecules. PRC1 might be a new and promising therapeutic target for NSCLC.

Regulation of proliferation and cell cycle by protein regulator of cytokinesis 1 in oral squamous cell carcinoma

Protein regulator of cytokinesis 1 (PRC1), a microtubule-associated protein, has emerged as a critical regulator of proliferation and apoptosis, acting predominantly in numerous tumors. However, its function in oral squamous cell carcinoma (OSCC) is still unknown. To establish the roles of PRC1 in OSCC, 95 oral clinical samples (54 OSCC, 24 oral leukoplakia [OLK], and 17 normal oral mucosa) and seven oral cell lines (6 OSCC and 1 normal oral cell lines) were analyzed using a series of molecular and genomic assays both in vivo and in vitro were conducted in this study. Herein, we provide evidence demonstrating that expression of PRC1 closely correlates with the degree of epithelial dysplasia in OLK (n = 24) (p < 0.001), and the poor differentiation, large tumor volume, lymph node metastasis, and high-clinical stage in OSCC (n = 54) (p < 0.05), illustrating that PRC1 has a promotive influence on tumor progression in OSCC. Simultaneously, we observed that PRC1 knockdown in OSCC cell lines caused G2/M phase arrest (p < 0.05), inhibited cell proliferation in vitro (p < 0.05) and tumor growth in vivo (p < 0.001). Furthermore, the effects of PRC1 on the regulation of proliferation and cell cycle transition in OSCC samples were mediated by p53. The p53/PRC1/EGFR signaling pathway was found to be implicated in the tumor progression of OSCC. Based on our data, we demonstrate that PRC1 is a key factor in regulating proliferation and the cell cycle, pointing to the potential benefits of PRC1-targeted therapies for OSCC.

Protein regulator of cytokinesis-1 expression: prognostic value in lung squamous cell carcinoma patients.

Protein regulator of cytokinesis-1 (PRC1) has been shown to participate in the completion of cytokinesis, and it is dysregulated in cancer processes. However, its relevance in lung squamous cell carcinoma (SCC) remained largely unknown. We aimed to study the expression pattern of PRC1 and assess its clinical significance in lung SCC. PRC1 protein expression in human lung SCC and adjacent normal lung tissues was detected by immunohistochemistry. PRC1 expression was assessed in association with clinicopathological features and clinical outcomes of lung SCC patients. In lung SCC tissues, PRC1 protein expression was significantly higher than those in paired normal lung tissues. The lung SCC patients with PRC1 overexpression had an advanced pathological stage (TNM stage), positive lymph node metastasis, and a shorter overall survival (OS) time more frequently than patients with low PRC1 expression. Additional, PRC1 expression was also shown to be poor as a prognostic factor for OS in patients with lung SCC. Our study indicated that aberrant expression of PRC1 may point to biochemical recurrence in lung SCC. This highlights its potential as a valuable prognostic marker for lung SCC.

Elevated PRC1 in gastric carcinoma exerts oncogenic function and is targeted by piperlongumine in a p53‐dependent manner

Gastric carcinoma is one of the most common malignancies worldwide and the second most frequent cause of cancer‐related death in China. Protein regulator of cytokinesis 1 (PRC1) is involved in cytokinesis and plays key roles in microtubule organization in eukaryotes. This study was aimed to analyse the expression and to investigate the functional role of PRC1 in gastric tumorigenesis. The expression of PRC1 was evaluated by qRT‐PCR, Western blot and immunohistochemistry. The biological function of PRC1 was determined by CCK‐8 proliferation assays, monolayer colony formation, xenografted nude mice and cell invasion assays by shRNA‐mediated knockdown in AGS and HGC27 cells. The regulation of PRC1 expression by piperlongumine was also investigated using dual‐luciferase reporter assay and ChIP‐qPCR analysis. PRC1 was up‐regulated in primary gastric cancers. Overexpression of PRC1 in gastric cancers was associated with poor disease‐specific survival and overall survival. PRC1 knockdown in AGS and HGC27 cell lines suppressed proliferation, reduced monolayer colony formation, inhibited cell invasion and migration ability and induced cell‐cycle arrest and apoptosis. Inhibition of PRC1 also suppressed tumour growth in vivo. We finally confirmed that PRC1 is a novel downstream target of piperlongumine in gastric cancer. Our findings supported the oncogenic role of PRC1 in gastric carcinogenesis. PRC1 might serve as a prognostic biomarker and potential therapeutic target for gastric carcinoma.

The microtubule-associated protein PRC1 promotes early recurrence of hepatocellular carcinoma in association with the Wnt/β-catenin signalling pathway

ObjectivesHepatocellular carcinoma (HCC) is the second leading cause of cancer mortality worldwide. Alterations in microtubule-associated proteins (MAPs) have been observed in HCC. However, the mechanisms underlying these alterations remain poorly...

Protein regulator of cytokinesis 1 overexpression predicts biochemical recurrence in men with prostate cancer.

Protein regulator of cytokinesis 1 (PRC1) has been reported to be implicated into the completion of cytokinesis and is dys-regulated in a cancer-specific manner. However, it roles in human prostate cancer (PCa) remain unclear. In the current study, we aimed to investigate the expression pattern of PRC1 and its clinical significance in this malignancy. PRC1 protein expression in human PCa and non-cancerous prostate tissues was detected by immunohistochemistry, which was validated by microarray-based Taylor data at mRNA level. Then, the associations of PRC1 expression with clinicopathological features and clinical outcome of PCa patients were statistically analyzed. PRC1 expression in PCa tissues, at both mRNA and protein levels, were significantly higher than those in non-cancerous prostate tissues. In addition, the PCa patients with PRC1 overexpression more frequently had high Gleason score, advanced pathological stage, positive metastasis, short overall survival time and positive PSA failure than those with low Gleason score, early pathological stage, negative metastasis, long overall survival time and negative PSA failure (all P<0.05). Moreover, PRC1 expression was identified as an unfavorable prognostic factor of biochemical recurrence-free survival in PCa patients (P<0.001). These findings suggest that the aberrant expression of PRC1 may predict biochemical recurrence in men with PCa highlighting its potential as a prognostic marker of this malignancy.

Transcriptional targeting of gene expression in breast cancer by the promoters of protein regulator of cytokinesis 1 and ribonuclease reductase 2

For cancer gene therapy, cancer-specific over- expression of a therapeutic gene is required to reduce side effects derived from expression of the gene in normal cells. To develop such an expression vector, we searched for genes over-expressed and/or specifically expressed in cancer cells using bioinformatics and have selected genes coding for protein regulator of cytokinesis 1 (PRC1) and ribonuclease reductase 2 (RRM2) as candidates. Their cancer-specific expressions were confirmed in both breast cancer cell lines and patient tissues. We compared each promoter's cancer-specific activity in the breast normal and cancer cell lines using the luciferase gene as a reporter and confirmed cancer-specific expression of both PRC1 and RRM2 promoters. To test activities of these promoters in viral vectors, the promoters were also cloned into an adeno-associated viral (AAV) vector containing green fluorescence protein (GFP) as the reporter. The GFP expression levels by these promoters were various depending on cell lines tested and, in MDA-MB-231 cells, GFP activities derived from the PRC1 and RRM2 promoters were as strong as that from the cytomegalovirus (CMV) promoter. Our result showed that a vector containing the PRC1 or RRM2 promoter could be used for breast cancer specific overexpression in gene therapy.

Oncogenic Role of MPHOSPH1, a Cancer-Testis Antigen Specific to Human Bladder Cancer

To disclose the molecular mechanism of bladder cancer, the second most common genitourinary tumor, we had previously done genome-wide expression profile analysis of 26 bladder cancers by means of cDNA microarray representing 27,648 genes. Among genes that were significantly up-regulated in the majority of bladder cancers, we here report identification of M-phase phosphoprotein 1 (MPHOSPH1) as a candidate molecule for drug development for bladder cancer. Northern blot analyses using mRNAs of normal human organs and cancer cell lines indicated this molecule to be a novel cancer-testis antigen. Introduction of MPHOSPH1 into NIH3T3 cells significantly enhanced cell growth at in vitro and in vivo conditions. We subsequently found an interaction between MPHOSPH1 and protein regulator of cytokinesis 1 (PRC1), which was also up-regulated in bladder cancer cells. Immunocytochemical analysis revealed colocalization of endogenous MPHOSPH1 and PRC1 proteins in bladder cancer cells. Interestingly, knockdown of either MPHOSPH1 or PRC1 expression with specific small interfering RNAs caused a significant increase of multinuclear cells and subsequent cell death of bladder cancer cells. Our results imply that the MPHOSPH1/PRC1 complex is likely to play a crucial role in bladder carcinogenesis and that inhibition of the MPHOSPH1/PRC1 expression or their interaction should be novel therapeutic targets for bladder cancers.