RPB5-mediating protein is required for the proliferation of hepatocellular carcinoma cells

AdipoR1 enhances the radiation resistance via ESR1/CCNB1IP1/cyclin B1 pathway in hepatocellular carcinoma cells

Hepatocellular carcinoma is one of the most common malignant tumors, and radiotherapy plays a pivotal role in its therapeutic regimen. However, radiotherapy resistance is the main cause of therapeutic failure in patients. Our previous study revealed that Adiponectin Receptor 1 (AdipoR1) is involved in regulating radiation resistance in liver cancer patients treated with stereotactic body radiotherapy. To explore the mechanism, we performed high-throughput transcriptome sequencing of hepatocellular carcinoma cells with stable knockdown of AdipoR1. KEGG enrichment analysis indicated that the cell cycle and ubiquitination degradation pathways may be involved in the regulation of radiation resistance by AdipoR1.The knockdown of AdipoR1 can attenuate the radiation-induced G2/M phase arrest through cyclin B1.By the ubiquitination IP assay and a rescue experiment, we confirmed that CCNB1IP1 regulated the ubiquitination and degradation of cyclin B1. Combined with information from transcription factor database and AdipoR1 transcriptome sequencing, these results showed that estrogen receptor 1 (ESR1) may be a transcription factor of CCNB1IP1. We found that AdipoR1 promoted the translocation of ESR1 from the cytoplasm to the nucleus, and ESR1 inhibited the transcription of CCNB1IP1.Therefore, we propose that AdipoR1 regulates the ubiquitination level, cell cycle progression, and radiation resistance of HCC cells through the "AdipoR1 /ESR1/CCNB1IP1/cyclin B1" axis. This study will promote the development of novel targeted radiosensitizing drugs.

Re-exploration of immunotherapy targeting EMT of hepatocellular carcinoma: Starting from the NF-κB pathway

Hepatocellular carcinoma (HCC) is the fifth most common malignancies worldwide, and its high morbidity and mortality have brought a heavy burden to the global public health system. Due to the concealment of its onset, the limitation of treatment, the acquisition of multi-drug resistance and radiation resistance, the treatment of HCC cannot achieve satisfactory results. Epithelial mesenchymal transformation (EMT) is a key process that induces progression, distant metastasis, and therapeutic resistance to a variety of malignant tumors, including HCC. Therefore, targeting EMT has become a promising tumor immunotherapy method for HCC. The NF-κB pathway is a key regulatory pathway for EMT. Targeting this pathway has shown potential to inhibit HCC infiltration, invasion, distant metastasis, and therapeutic resistance. At present, there are still some controversies about this pathway and new ideas of combined therapy, which need to be further explored. This article reviews the progress of immunotherapy in improving EMT development in HCC cells by exploring the mechanism of regulating EMT.

Parafibromin Is Highly Expressed in Hepatocellular Carcinoma and Its Expression Correlates with Poor Prognosis

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide. Much progress has been made regarding the understanding of hepatocarcinogenesis, yet the long-term survival rate of HCC patients remains poor. Recent efforts have shown parafibromin has a pathologic role in many human cancers, but little is known about the effects of parafibromin in HCC. This study aimed to investigate the pattern of parafibromin expression and its clinicopathologic significance in human HCC. Immunohistochemical analysis of HCC and matched non-tumor liver tissues from 50 HCC patients showed that the nuclear expression of parafibromin was higher in HCC tissues (50/50 cases) than in non-tumor liver tissues (17/50 cases). Moreover, elevated parafibromin expression was found to be significantly correlated with the presence of microvascular invasion (p = 0.017), hepatitis virus infection-induced occurrence (p = 0.005), and poorer tumor differentiation (Edmondson-Steiner grade; p = 0.000). Kaplan-Meier analysis showed that HCC patients with elevated parafibromin expression had poorer recurrence-free (p = 0.014, log-rank test = 6.079) and overall survival (p = 0.036, log-rank test = 4.414). These findings indicate parafibromin may be related to the pathogenesis of HCC and a potential prognostic marker for HCC patients after hepatectomy.

Integrating microRNA expression, miRNA-mRNA regulation network and signal pathway: a novel strategy for lung cancer biomarker discovery

Background

Since there are inextricably connections among molecules in the biological networks, it would be a more efficient and accurate research strategy to screen microRNA (miRNA) markers combining with miRNA-mRNA regulatory networks. The independent regulation mode is more “fragile” and “influential” than the co-regulation mode. miRNAs can be used as biomarkers if they can independently regulate hub genes with important roles in the PPI network, simultaneously the expression products of the regulated hub genes play important roles in the signaling pathways of related tissue diseases.

Methods

We collected miRNA expression of non-small cell lung cancer (NSCLC) from The Cancer Genome Atlas (TCGA) database and the Gene Expression Omnibus (GEO) database. Volcano plot and signal-to-noise ratio (SNR) methods were used to obtain significant differentially expressed (SDE) miRNAs from the TCGA database and GEO database, respectively. A human miRNA-mRNA regulatory network was constructed and the number of genes uniquely targeted (NOG) by a certain miRNA was calculated. The area under the curve (AUC) values were used to screen for clinical sensitivity and specificity. The candidate markers were obtained using the criteria of the top five maximum AUC values and NOG ≥ 3. The protein–protein interaction (PPI) network was constructed and independently regulated hub genes were obtained. Gene Ontology (GO) analysis and KEGG pathway analysis were used to identify genes involved in cancer-related pathways. Finally, the miRNA which can independently regulate a hub gene and the hub gene can participate in an important cancer-related pathway was considered as a biomarker. The AUC values and gene expression profile analysis from two external GEO datasets as well as literature validation were used to verify the screening capability and reliability of this marker.

Results

Fifteen SDE miRNAs in lung cancer were obtained from the intersection of volcano plot and SNR based on the GEO database and the TCGA database. Five miRNAs with the top five maximum AUC values and NOG ≥ 3 were screened out. A total of 61 hub genes were obtained from the PPI network. It was found that the hub gene GTF2F2 was independently regulated by miR-708-5p. Further pathway analysis indicated that GTF2F2 participates in protein expression by binding with polymerase II, and it can regulate transcription and accelerate tumor growth. Hence, miR-708-5p could be used as a biomarker. The good screening capability and reliability of miR-708-5p as a lung cancer marker were confirmed by AUC values and gene expression profiling of external datasets, and experimental literature. The potential mechanism of miR-708-5p was proposed.

Conclusions

This study proposes a new idea for lung cancer marker screening by integrating microRNA expression, regulation network and signal pathway. miR-708-5p was identified as a biomarker using this novel strategy. This study may provide some help for cancer marker screening.

Identification of Key Genes Associated With the Process of Hepatitis B Inflammation and Cancer Transformation by Integrated Bioinformatics Analysis

Background

Hepatocellular carcinoma (HCC) has become the main cause of cancer death worldwide. More than half of hepatocellular carcinoma developed from hepatitis B virus infection (HBV). The purpose of this study is to find the key genes in the transformation process of liver inflammation and cancer and to inhibit the development of chronic inflammation and the transformation from disease to cancer.

Methods

Two groups of GEO data (including normal/HBV and HBV/HBV-HCC) were selected for differential expression analysis. The differential expression genes of HBV-HCC in TCGA were verified to coincide with the above genes to obtain overlapping genes. Then, functional enrichment analysis, modular analysis, and survival analysis were carried out on the key genes.

Results

We identified nine central genes (CDK1, MAD2L1, CCNA2, PTTG1, NEK2) that may be closely related to the transformation of hepatitis B. The survival and prognosis gene markers composed of PTTG1, MAD2L1, RRM2, TPX2, CDK1, NEK2, DEPDC1, and ZWINT were constructed, which performed well in predicting the overall survival rate.

Conclusion

The findings of this study have certain guiding significance for further research on the transformation of hepatitis B inflammatory cancer, inhibition of chronic inflammation, and molecular targeted therapy of cancer.

URI1 suppresses irradiation-induced reactive oxygen species (ROS) by activating autophagy in hepatocellular carcinoma cells

Radiotherapy has been extensively applied in cancer treatment. However, this treatment is ineffective in Hepatocellular carcinoma (HCC) due to lack of radiosensitivity. Unconventional prefoldin RPB5 interactor 1 (URI1) exhibits characteristics similar to those oncoproteins, which promotes survival of cancer cells. As a consequence of the irradiation, the levels of endogenous reactive oxygen species (ROS) rise. In the current study, we analyzed the role of URI1 in the control of ROS levels in HepG2 cells. Upon URI1 overexpression, HepG2 cells significantly suppressed irradiation-induced ROS, which may help cells escape from oxidative toxicity. And our data demonstrated that overexpression of URI1 not only resulted in an increase of autophagic flux, but also resulted in an further increased capacity of autophagy to eliminate ROS. It indicated that URI1 suppressed irradiation-induced ROS through activating autophagy. Moreover, URI1 activated autophagy by promoting the activities of AMP-activated protein kinase (AMPK). Results showed that overexpression of URI1 increased the phosphorylation of AMPKα at the Thr172 residue and the activated-AMPK promoted the phosphorylation of forkhead box O3 (FOXO3) at the Ser253 residue, which significantly induced autophagy. Taken together, our findings provide a mechanism that URI1 suppresses irradiation-induced ROS by activating autophagy through AMPK/FOXO3 signaling pathway. These new molecular insights will provide an important contribution to our better understanding about irradiation insensitivity of HCC.

RNA polymerase II subunit 3 regulates vesicular, overexpressed in cancer, prosurvival protein 1 expression to promote hepatocellular carcinoma

OBJECTIVE

To explore the relationships between hepatocellular carcinoma (HCC) and the expression of RNA polymerase II subunit 3 (RPB3) and vesicular, overexpressed in cancer, prosurvival protein 1 (VOPP1), and to determine whether RPB3 regulates VOPP1 expression to promote HCC cell proliferation, tumor growth, and tumorigenesis.

METHODS

HCC and adjacent liver samples were collected from 51 patients with HCC who underwent surgical excision between September 20, 2010 and June 22, 2017. Immunohistochemical staining, western blot, quantitative PCR, plate colony assay, and RNA microarray were used to detect relevant indexes for further analyses.

RESULTS

VOPP1 was shown to function as a target gene of RPB3 in facilitating HCC proliferation, and was downregulated after RBP3 silencing. Additionally, hepatic tumor tissues demonstrated high VOPP1 expression. Furthermore, VOPP1 silencing suppressed tumor growth and cell proliferation and elicited apoptosis.

CONCLUSION

RPB3 regulates VOPP1 expression to promote HCC cell proliferation, tumor growth, and tumorigenesis.

RPB5-mediating protein promotes the progression of non-small cell lung cancer by regulating the proliferation and invasion

Background

This study aimed to investigate the relationship between RNA polymerase II subunit 5 (RPB5)-mediating protein (RMP) and clinicopathological characteristics of non-small cell lung cancer (NSCLC) patients by measuring the expression level of RMP in human NSCLC tissues and cell lines. At the same time, we studied the impact of RMP on the biological function of cancer, providing strong support for gene targeted therapy of NSCLC.

Methods

Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot were used to determine the expression levels of messenger (m)RNA and protein in NSCLC cell lines and tissues. Cell counting kit 8 (CCK8) assay and flow cytometry were selected to detect cell proliferation, cycle and apoptosis. The wound healing assay was chosen to detect the migration and invasion ability of cells. The xenograft model was performed to study the function of RMP in vivo. Immunohistochemical (IHC) staining showed the levels of RMP, Bcl-2, Bax and caspase-3.

Results

First, mRNA and protein levels of RMP were relatively overexpressed in NSCLC cells. Compared with the corresponding normal tissues, the mRNA and protein levels of RMP were significantly higher in human NSCLC tissues. Concurrently, we found that the expression of RMP was related to the status of lymph nodes (LNs) in cancer tissues and T stage. Then, RMP overexpression promoted the proliferation of A549. At the same time, RMP provided A549 cells the ability to resist chemotherapy and radiotherapy; when A549 cells were treated with gefitinib and radiation, RMP reduced apoptosis. We also found that RMP can protect A549 from G2 block caused by radiation. Over-irradiated RMP-overexpressed A549 cells had lower Bcl2-associated X protein (Bax) levels and higher B-cell lymphoma 2 (Bcl-2) levels. The migration and invasion ability of A549 cells was increased by RMP. Finally, RMP can promote tumor growth by increasing Bcl-2 levels and decreasing Bax and caspase-3 levels in the xenograft model.

Conclusions

There is potential for RMP to develop into a diagnostic and therapeutic target for NSCLC.

Construction and analysis of a diabetic nephropathy related protein-protein interaction network reveals nine critical and functionally associated genes

Diabetic nephropathy (DN) is one of the common diabetic complications, but the mechanisms are still largely unknown. In this study, we constructed a DN related protein-protein interaction network (DNPPIN) on the basis of RNA-seq analysis of renal cortices of DN and normal mice, and the STRING database. We analyzed DNPPIN in detail revealing nine critical proteins which are central in DNPPIN, and contained in one network module which is functionally enriched in ribosome, nucleic acid binding and metabolic process. Overall, this study identified nine critical and functionally associated protein-coding genes concerning DN. These genes could be a starting point of future research towards the goal of elucidating the mechanisms of DN pathogenesis and progression.

The Expression of MicroRNA-598 Inhibits Ovarian Cancer Cell Proliferation and Metastasis by Targeting URI

Unconventional prefoldin RPB5 interactor (URI, or RMP, a member of the prefoldin family of molecular chaperones) exhibits oncogenic activity in several types of cancer, including ovarian cancer. However, the underlying regulatory mechanism in ovarian cancer remains unclear. MicroRNAs (miRNAs) negatively regulate gene expression, and their dysregulation has been implicated in tumorigenesis. To elucidate the role of miRNAs in URI-induced ovarian cancer, miR-598 and URI were overexpressed in the SKOV3 ovarian cancer cell line. The CCK8 kit was used to determine cell proliferation, and the Transwell assay was used to measure cell invasion and migration. RT-PCR and western blotting were used to analyze the expression of miR-598 and URI, and the luciferase reporter assay was used to examine the interaction between miR-598 and URI. Nude mice were used to characterize the regulation of tumor growth in vivo. The results showed that the expression of miR-598 inhibited the proliferation, invasion, and migration of ovarian cancer cells by targeting URI. The inhibitory effect of miR-598 was reversed by overexpression of URI. The luciferase reporter assay showed that miR-598 downregulated URI by directly targeting the 3′ UTR of URI. In vivo studies showed that the expression of miR-598 significantly inhibited the growth of tumors. Taken together, the results suggested that miR-598 inhibited tumor growth and metastasis by targeting URI.

URI knockdown induces autophagic flux in gastric cancer cells

URI, a member of the prefoldin family of molecular chaperones, functions in the regulation of nutrient-sensitive, mTOR-dependent transcription signaling pathways. Previous studies of several tumor types demonstrated that URI exhibits characteristics similar to those of an oncoprotein. URI has been shown as a mitochondrial substrate of S6 kinase 1 (S6K1), which acts to integrate nutrient and growth factor signals to promote cell growth and survival. Notably, the Akt/mTOR/p70S6K signaling pathway constitutes major negative regulatory mechanism of autophagy. However, the role of URI in autophagy has not been explored. Here, we investigated the involvement of URI in autophagy by manipulating its expression in MGC-803 and HGC-27 cells using siRNA and transfection approaches. GFP-LC3 punctum aggregation was assessed by confocal microscopy, whereas formation of autophagic vesicles was assessed using transmission electron microscopy. NH₄Cl was used to inhibit autophagosome-lysosome fusion and to monitor autophagic flux. Expression of LC3-I, LC3-II, beclin1, total and phosphorylated mTOR, and p70S6k was assessed by Western blotting. The results showed that knockdown of URI induced significant autophagic flux in gastric cancer cells. URI regulates the expression of beclin1, which is essential for initiation of conventional autophagy. Levels of p-mTOR (Ser2448) and p-p70S6K (Thr389) increased in URI-overexpressing cells treated with the mTOR inhibitor rapamycin but decreased in URI-silenced cells. The inhibitory effect of URI silencing on mTOR and p70S6K phosphorylation was antagonized by the autophagy inhibitor 3-methyladenine. These results suggest that URI knockdown-induced autophagy is associated with the mTOR/p70S6K signaling pathway, indicating the potential existence of a novel autophagy regulatory mechanism mediated by URI.

RMP promotes epithelial-mesenchymal transition through NF-κB/CSN2/Snail pathway in hepatocellular carcinoma

Epithelial-mesenchymal transition (EMT) is a significant risk factor for metastasis in hepatocellular carcinoma (HCC) patients and with poor prognosis. In this study, we demonstrate the key role of RPB5-mediating protein (RMP) in EMT of HCC cells and the mechanism by which RMP promote EMT. RMP increases migration, invasion, and the progress of EMT of HCC cells, which facilitates the accumulation of Snail, a transcriptional repressor involved in EMT initiation. NF-κB is activated by RMP, which directly promotes the expression of COP9 signalosome 2 (CSN2) to repress the degradation of Snail. Pulmonary metastases mouse model demonstrates that RMP induces metastasis in vivo. Immunohistochemical analysis of human HCC tissues confirms the correlation of RMP with the expression of E-cadherin, p65, CSN2 and Snail in vivo. Collectively, these findings indicate that RMP promotes EMT and HCC metastasis through NF-κB/CSN2/Snail pathway. These results suggest that RMP and p65 may serve as potential candidates of the targets in the treatment of metastatic HCC.

Role of the PAQosome in Regulating Arrangement of Protein Quaternary Structure in Health and Disease

The PAQosome, formerly known as the R2TP/PFDL complex, is an eleven-subunit cochaperone complex that assists HSP90 in the assembly of numerous large multisubunit protein complexes involved in essential cellular functions such as protein synthesis, ribosome biogenesis, transcription, splicing, and others. In this review, we discuss possible mechanisms of action and role of phosphorylation in the assembly of client complexes by the PAQosome as well as its potential role in cancer, ciliogenesis and ciliopathies.

URI promotes the migration and invasion of human cervical cancer cells potentially via upregulation of vimentin expression

URI is known to act as an oncoprotein in several tumors. Our previous studies have shown that URI is associated with the migration process in cervical and gastric cancer cells, but the mechanisms remain to be determined. Given the fact that URI positively regulates vimentin expression, we therefore investigated how URI regulated vimentin expression affects the migration and invasion of cells from two human cervical cancer cell lines HeLa and C33A, which differentially express URI. We have shown that knock-down of URI in HeLa cells using URI siRNA caused decreased vimentin mRNA and protein levels along with attenuated cell motility. Meanwhile, overexpression of URI by transfection of PCMV6-URI in C33A cells resulted in increased vimentin expression and enhanced cell migration and invasion. We have also used TGF-β to induce vimentin expression, which enhanced the cell migration and invasion abilities affected by URI, while inhibition of vimentin by siRNA attenuated URI's effect on cell migration and invasion. In addition, we have performed luciferase reporter and ChIP assays, and the results support that URI indirectly enhances the activity of vimentin promoter. Taken together, our results suggest that URI plays essential roles in the migration and invasion of human cervical cancer cells, possibly via targeting vimentin expression.

R2TP/Prefoldin-like component RUVBL1/RUVBL2 directly interacts with ZNHIT2 to regulate assembly of U5 small nuclear ribonucleoprotein

The R2TP/Prefoldin-like (R2TP/PFDL) complex has emerged as a cochaperone complex involved in the assembly of a number of critical protein complexes including snoRNPs, nuclear RNA polymerases and PIKK-containing complexes. Here we report on the use of multiple target affinity purification coupled to mass spectrometry to identify two additional complexes that interact with R2TP/PFDL: the TSC1–TSC2 complex and the U5 small nuclear ribonucleoprotein (snRNP). The interaction between R2TP/PFDL and the U5 snRNP is mostly mediated by the previously uncharacterized factor ZNHIT2. A more general function for the zinc-finger HIT domain in binding RUVBL2 is exposed. Disruption of ZNHIT2 and RUVBL2 expression impacts the protein composition of the U5 snRNP suggesting a function for these proteins in promoting the assembly of the ribonucleoprotein. A possible implication of R2TP/PFDL as a major effector of stress-, energy- and nutrient-sensing pathways that regulate anabolic processes through the regulation of its chaperoning activity is discussed.

The R2TP/Prefoldin-like cochaperone complex is involved in the assembly of a number of protein complexes. Here the authors provide evidence that RUVBL1/RUVBL2, subunits of that cochaperone complex, directly interact with ZNHIT2 to regulate assembly of U5 small ribonucleoprotein.

URI prevents potassium dichromate-induced oxidative stress and cell death in gastric cancer cells

Chromium VI can provoke oxidative stress, DNA damage, cytotoxicity, mutagenesis and carcinogenesis. Aberrantly high level of reactive oxygen species (ROS) has been associated with oxidative stress and subsequent DNA damage. Notably, multiple previous studies have shown the increased level of ROS in chromium (VI) induced oxidative stress, but its effect on cell death and the underlying mechanism remain to be determined. In this study, we aimed to investigate the role of URI, an unconventional prefoldin RBP5 interactor, in potassium dichromate induced oxidative stress and cell death through in vitro loss-of-function studies. We have shown that knockdown of URI in human gastric cancer SGC-7901 cells by URI siRNA enhanced potassium dichromate-induced production of ROS. The level of rH2AX, a marker of DNA damage, was significantly increased, along with a reduced cell viability in URI siRNA treated cells that were also exposed to potassium dichromate. Comet assay showed that URI knockdown increased the tail moment in potassium dichromate-treated SGC-7901 cells. Accordingly, the cell rates of apoptosis and necrosis were also increased in URI knockdown cells treated with potassium dichromate at different concentrations. Together, these results suggest that URI is preventive for the oxidative stress and cell death induced by potassium dichromate, which potentially leads to cancer cell survival and therapeutic resistance.

The PDRG1 is an oncogene in lung cancer cells, promoting radioresistance via the ATM-P53 signaling pathway

PDRG1, is short for P53 and DNA damage-regulated gene, which have been found over 10 years. Although severe studies have described the roles of PDRG1 separately in many kinds of tumors, how to act as an oncogene are unclear. To better verify the function of PDRG1 in lung cancer, both loss-function and gain-function of PDRG1 studies based on two human lung cancer lines were performed. Following the transfection of PDRG1, both A549 and 95-D cells showed significant changes in cell viability, the expression of some protein and apoptosis, which were all implied the PDRG1 is an oncogene. Another interesting finding is PDRG1 could promote radioresistance involved the ATM-p53 signaling pathway in lung cancer. If we combine radiotherapy with gene-targeted therapy together effectively, predominant effect may be acquired, which is a huge milestone in clinical cure about lung cancer.

URI promotes gastric cancer cell motility, survival, and resistance to adriamycin in vitro

Unconventional prefoldin RPB5 interactor (URI), a RNA polymerase II Subunit 5-Interacting protein, is known to participate in the regulation of nutrient-sensitive mTOR-dependent transcription programs. Multiple studies have recently demonstrated that URI functions as an oncoprotein, possibly through the mTOR pathway, and regulates tumor cell motility, invasion, and metastasis. However, whether and how URI plays a role in gastric oncogenesis has not been elucidated. Due to drug resistance, recurrence and metastasis, the prognosis of gastric cancer remains poor. This study aims to explore the effects of URI on gastric cancer cells by focusing on their migratory ability and resistance to adriamycin. URI was over-expressed or knocked-down in MGC-803 and HGC-27 gastric cancer cells using URI plasmid or siRNA transfection approach. The cell viability, apoptosis, and migration ability were then examined by the CCK-8 assay, flow cytometer Annexin V/PI staining, and the Transwell cell migration assay respectively. The protein levels of apoptosis and EMT related genes were detected by western blot. The results showed that overexpression of URI promoted while knock-down of URI inhibited gastric cancer cell proliferation. URI overexpression resulted in increased Bcl-2 expression but decreased levels of Bax, cleaved PARP-1 and cleaved caspase-3. Conversely, cells treated with URI siRNA showed increased adriamycin induced apoptosis, along with reduced Bcl-2, but increased Bax, cleaved PARP-1 and cleaved caspase-3 expression. We have also shown that overexpression of URI enhanced cancer cell proliferation and migration with higher levels of Snail and Vimentin, whereas knockdown of URI in MGC-803 and HGC-27 cells inhibited proliferation and migration with decreased Snail and Vimentin expression. Together, our results support that URI promotes cell survival and mobility and acts as a chemotherapeutics resistant protein in MGC-803 and HGC-27 cells. URI might be a potential biomarker for gastric cancer diagnostics and prognostics.

RMP predicts survival and adjuvant TACE response in hepatocellular carcinoma

Adjuvant transcatheter arterial chemoembolization (TACE) protects against hepatocellular carcinoma (HCC) and is associated with reduced disease recurrence and improved outcome after surgery. However, deterioration of liver function after TACE negatively impacts the patient prognosis and limits it use as an option to prolong survival. We analyzed two independent cohorts that included a total of 510 patients with HCC who had undergone tumor resection. Immunohistochemistry assay was used to measure RPB5-mediating protein (RMP) expression and assessed their association with recurrence rate and response to therapy with adjuvant TACE. In patients with HCC, the expression of RMP in tumor is associated with age, gender, tumor size, portal venous invasion, TNM stages, BCLC stages and overall survival. Among patients with high RMP expression, adjuvant TACE after resection was associated with early recurrence. Even in the patients with small tumor size (no more than 5 cm) or no venous invasion, RMP status is associated with response to adjuvant TACE. RMP status in tumors may be a useful marker in estimating prognosis in patients with HCC and in assisting in the selection of patients who are likely to benefit from adjuvant TACE to prevent relapse.

URI expression in cervical cancer cells is associated with higher invasion capacity and resistance to cisplatin

Cervical cancer is a common and devastating female cancer worldwide. The etiology of cervical cancer has been largely attributed to human papillomavirus (HPV) infection and activation of the P13K/AKT/mTOR (mammalian target of rapamycin) pathway. However, the limited HPV-directed therapy, as well as therapeutic approach targeting P13K/AKT/mTOR pathway, has not yet been established or effective. A deeper understanding of cervical carcinogenesis and finding of novel candidate molecules for cervical cancer therapeutics is largely warranted. The unconventional prefoldin RPB5 interactor (URI or URI1), a known transcription factor involving the TOR signaling pathway, has recently been implicated a role in multiple tumorigenesis. We recently reported significant upregulation of URI in precancerous cervical intra-epithelial neoplasia (CIN) and invasive cervical cancer, suggesting its role in cervical carcinogenesis. However, the effect and underlying mechanism of URI in cervical cancer development have never been elucidated. Here, we aimed to investigate the in vitro effect of URI on cervical cancer using two cervical cancer cell lines CaSki and C33A, which are HPV-positive and HPV-negative respectively. We have shown that forced over-expression of URI in C33A and CaSki cells markedly promoted cell growth, while down-regulation of URI mediated by siRNA inhibited cell proliferation. We have found that URI over-expression enhanced resistance of cervical cancer cells to cisplatin. In contrast, knockdown of URI promoted apoptosis by influencing cell response to cisplatin, supporting URI as an oncogenic protein for cervical cancer cells. We have also shown that URI promoted the migration and invasive capacity of cervical cancer cells by up-regulation of Vimentin, a mesenchymal cell migration marker relating to the epithelial-mesenchymal transition (EMT) program. Our data support an important function of URI in the biological behavior of cervical cancer cells and provide novel mechanistic insights into the role of URI in cervical cancer progression and possibly, metastasis.

Boosting NAD(+) for the prevention and treatment of liver cancer

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide yet has limited therapeutic options. We recently demonstrated that inhibition of de novo nicotinamide adenine dinucleotide (NAD⁺) synthesis is responsible for DNA damage, thereby initiating hepatocarcinogenesis. We propose that boosting NAD⁺ levels might be used as a prophylactic or therapeutic approach in HCC.

The viral oncoprotein HBx of Hepatitis B virus promotes the growth of hepatocellular carcinoma through cooperating with the cellular oncoprotein RMP

The smallest gene HBx of Hepatitis B virus (HBV) is recognized as an important viral oncogene (V-oncogene) in the hepatocarcinogenesis. Our previous work demonstrated that RMP is a cellular oncogene (C-oncogene) required for the proliferation of hepatocellular carcinoma (HCC) cells. Here we presented the collaboration between V-oncogene HBx and C-oncogene RMP in the development of HCC. The coexpression of HBx and RMP resulted in the cooperative effect of antiapoptosis and proliferation of HCC cells. In vivo, overexpression of RMP accelerated the growth of HBx-induced xenograft tumors in nude mice and vice versa HBx promoted the growth of RMP-driven xenograft tumors. Although HBx didn't regulate the expression of RMP, HBx and RMP interact with each other and collocalized in the cytoplasm of HCC cells. HBx and RMP collaboratively inhibited the expression of apoptotic factors and promoted the expression of antiapoptotic factors. This finding suggests that HBV may induce, or at least partially contributes to the carcinogenesis of HCC, through its V-oncoprotein HBx interacting with the C-oncoprotein RMP.

URI regulates tumorigenicity and chemotherapeutic resistance of multiple myeloma by modulating IL-6 transcription

Unconventional prefoldin RPB5 interactor (URI), which acts as an oncoprotein in solid tumors, is associated with RNA polymerase II subunit 5. However, its impact on multiple myeloma (MM) has not been determined. We demonstrate here that URI is overexpressed in MM compared with plasma cells derived from healthy volunteers. Side population (SP) cells sorted from MM cells showed a much higher level of URI than non-SP cells. Using lentivirus-delivered shRNA, we established stable URI knockdown MM cell lines. URI inhibition significantly attenuated the proliferation of MM cells and decreased colony formation compared with the control cells. Tumor growth assays in NOD/SCID mice further confirmed the promotion role of URI during MM development in vivo. Furthermore, URI knockdown markedly reduced the abundance of SP in MM cell lines and enhanced the chemotherapeutic sensitivity of MM towards bortezomib. Mechanically, URI appears to be critically involved in modulating STAT3 activity through regulating interleukin (IL)-6 transcription via interaction with NFκBp65. In conclusion, URI may have an important role in the development of MM and chemotherapeutic resistance through activating the IL-6/STAT3 pathway.

Expression analysis of URI/RMP gene in endometrioid adenocarcinoma by tissue microarray immunohistochemistry

Multiple studies have recently demonstrated the oncogenic property of URI (or RMP, a member of the prefoldin family of molecular chaperones) during progression of hepatocellular carcinoma, ovarian cancer, and possibly prostate cancer. Most recently, we have shown that URI/RMP is up-regulated in cervical cancer, another reproductive system tumor beside ovarian and prostate cancers. To investigate if URI/RMP also plays a role in other reproductive system tumors, especially in endometrioid adenocarcinoma, we analyzed URI/RMP expression in a TMA (tissue microarray) containing tissues from 30 cases of endometrioid adenocarcinoma (which covers tumor tissues from Grade I through Grade III) and adjacent endometrium by immunohistochemistry (IHC) and densitometry analysis using image-pro plus 6.0 software. Our results showed that the mean density of URI/RMP expression in cancerous tissue is slightly higher than that of the adjacent endometrial tissue, though not statistically significant (p>0.05). There is no significant difference either between the mean density of Grade III cancerous tissue and that of Grade I and II cancers. Notably, we detected significantly higher signal intensity in cancerous tissue of all 7 Grade III cases than that of their adjacent endometrial tissue (p<0.05), suggesting a correlation of URI/RMP expression with the differentiation and pathological classification of endometrioid adenocarcinoma. Together, our results demonstrate the heterogeneous expression of URI/RMP in endometrioid adenocarcinoma. The higher level of URI/RMP expression in high-grade endometrioid adenocarcinomas compared to tissues of adjacent endometrium or gland suggests a diagnostic and possibly, a prognostic value of URI/RMP in endometrioid adenocarcinoma.

RMP plays distinct roles in the proliferation of hepatocellular carcinoma cells and normal hepatic cells

RMP has been shown to function in the transcription regulation through association with RNA polymerase (RNAP) II subunit RPB5. It also has been shown to be required for the proliferation of hepatocellular carcinoma (HCC) cells with an antiapoptotic property. In this article, we further demonstrate that RMP displays distinct features in HCC cells compared with normal hepatic cells. RMP expression is remarkably increased in various cancer cell lines including HCC cells when compared with normal cells. Depletion of RMP could inhibit the proliferation of HCC cells, but not the normal hepatic cells. RMP significantly prevented apoptosis of HCC cells in SMMC-7721 and HepG2, but had little effect on apoptosis in the normal hepatic cells. The mechanisms of RMP's distinct features rely on different responsive expressions of apoptosis factors induced by RMP in HCC and hepatic cells. Either overexpression or depletion of RMP significantly affected the expression of apoptosis factors in HCC cells. However, normal hepatic cells showed a tendency to resist RMP for the regulation of apoptosis. In the clinical samples, the increased expression of RMP in HCCs was also observed when compared with the matched non-tumor tissues from 30 HCC patients. The different expression levels of and distinct responses to RMP between HCC and hepatic cells suggest that RMP might serve as not only a biomarker for the diagnosis of HCC, but also a potential target for the HCC therapy.

Upregulation of URI/RMP gene expression in cervical cancer by high-throughput tissue microarray analysis

URI, or RMP, is a RNA polymerase II subunit RPB5-associated protein known to play essential roles in ubiquitination and transcription. Recently, we and others have shown that URI/RMP is also important for progression of hepatocellular carcinoma, ovarian, and prostate cancers. To identify the mechanistic basis of URI/RMP during multiple cellular processes, we investigated URI/RMP expression in a tissue microarray (TMA) containing multiple normal human tissues. The results showed that URI/RMP is ubiquitously but differentially expressed in these human tissues which partially explains its multiple cellular functions. To elucidate the role of URI/RMP during oncogenesis of multiple malignancies, especially the tumors of reproductive system, we analyzed URI/RMP expression in a TMA containing multiple reproductive system tumors. We did not observe significant difference of URI/RMP expression between cancerous and adjacent tissues of the prostate, breast, ovarian, and endometrial cancers. However, increased URI/RMP expression was observed in two of the three cases of cervical SCC (squamous cell carcinoma) cells compared to their adjacent epithelial cells. Moreover, we detected significantly upregulated URI/RMP expression not only in cervical cancers but also in pre-cancerous CINs (cervical intra-epithelial neoplasias) in a TMA that covers the whole spectrum of normal cervix, CINs, and cervical cancers. No difference of URI/RMP expression was observed between CINs and cervical cancers. Given the high risk of CINs (especially CIN3) turning into cervical cancer if left untreated, the increased URI/RMP expression in CINs as well as in cervical cancers suggest a clinical relevance of URI/RMP upon cervical cancer tumorigenesis and worth further investigation.

The suppressive effect of metabotropic glutamate receptor 5 (mGlu5) inhibition on hepatocarcinogenesis

Metabotropic glutamate receptors (mGlus) are G-protein-coupled receptors playing an important role in the central nervous system (CNS). Recently, mGlus have been identified in peripheral tissues, and aberrant expression or inhibition of the receptors functions in the development of certain cancers. However, the correlation of mGlu activity with hepatocellular carcinoma (HCC) remains unknown. In this study, we analyzed the effects of inhibiting mGlu5 activity in hepatocarcinoma cell lines and a xenograft model. Inactivation of mGlu5 with 2-Methyl-6-(phenylethyl)-pyridine (MPEP), a specific antagonist of the receptor, caused inhibition of cell growth, migration, and invasion of HepG2 and Bel-7402 cells, assessed by MTT assay, ATP production, wound healing, and Boyden chamber assay, respectively. Moreover, inhibition of tumor growth and the potential metastasis of hepatocellular carcinoma were also found in nude mice. Furthermore, mGlu5-mediated extracellular signal-regulated kinase (ERK) phosphorylation has been found to be partially involved in cell growth and migration, as detected by stimulation of (S)-3,5-Dihydroxyphenylglycine (DHPG), an agonist of the receptor, and blockage of MPEP and U0126, an inhibitor of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (MEK). These data indicate that inhibiting the activity of mGlu5 has the molecular potential to suppress oncogenic actions by blocking downstream effector molecules. The study suggests that mGlu5 activity may contribute to understanding the development of HCC.