PBK phosphorylates MSL1 to elicit epigenetic modulation of CD276 in nasopharyngeal carcinoma.

CD276 (also known as B7-H3, an immune checkpoint molecule) is aberrantly overexpressed in many cancers. However, the upregulation mechanism and in particular, whether oncogenic signaling has a role, is unclear. Here we demonstrate that a pro-oncogenic kinase PBK, the expression of which is associated with immune infiltration in nasopharyngeal carcinoma (NPC), stimulates the expression of CD276 epigenetically. Mechanistically, PBK phosphorylates MSL1 and enhances the interaction between MSL1 and MSL2, MSL3, and KAT8, the components of the MSL complex. As a consequence, PBK promotes the enrichment of MSL complex on CD276 promoter, leading to the increased histone H4 K16 acetylation and the activation of CD276 transcription. In addition, we show that CD276 is highly upregulated and associated with immune infiltrating levels in NPC. Collectively, our findings describe a novel PBK/MSL1/CD276 signaling axis, which may play an important role in immune evasion of NPC and may be targeted for cancer immunotherapy.

Pseudogene RACGAP1P activates RACGAP1/Rho/ERK signalling axis as a competing endogenous RNA to promote hepatocellular carcinoma early recurrence.

Accumulating evidence has indicated crucial roles for pseudogenes in human cancers. However, the roles played by pseudogenes in the pathogenesis of HCC, particularly HCC early recurrence, still incompletely elucidated. Herein, we identify a novel early recurrence related pseudogene RACGAP1P which was significantly upregulated in HCC and was associated with larger tumour size, advanced clinical stage, abnormal AFP level and shorter survival time. In vitro and in vivo experiments have shown that RACGAP1P is a prerequisite for the development of malignant characteristics of HCC cells, including cell growth and migration. Mechanistic investigations indicated that RACGAP1P elicits its oncogenic activity as a ceRNA to sequestrate miR-15-5p from its endogenous target RACGAP1, thereby leading to the upregulation of RACGAP1 and the activation of RhoA/ERK signalling. These results may provide new insights into the functional crosstalk of the pseudogene/miRNA/parent-gene genetic network during HCC early relapse and may contribute to improving the clinical intervention for this subset of HCC patients.

Overexpression of Nogo receptor 3 (NgR3) correlates with poor prognosis and contributes to the migration of epithelial cells of nasopharyngeal carcinoma patients.

Lymph node metastasis (N classification) is one of the most important prognostic factors of nasopharyngeal carcinoma (NPC), and nerve involvement is associated with the transition of the N category in NPC patients. Although the nervous system has been reported to participate in many types of cancer progression, its functions in NPC progression remains unknown. Through analysis of gene profiling data, we demonstrate an enrichment of genes associated with neuronal development and differentiation in NPC tissues and cell lines. Among these genes, Nogo receptor 3 (NgR3), which was originally identified in the nervous system and plays a role in nerve development and regeneration, was inappropriately overexpressed in NPC cells and tissues. Immunohistochemical analysis demonstrated that the overexpression of NgR3 was correlated with poor prognosis in NPC patients. Overexpression of NgR3 promoted, and knocking down NgR3 inhibited, NPC cell migration and invasion in vitro and metastasis in vivo. The ability of NgR3 to promote cell migration was triggered by the downregulation of E-cadherin and enhanced cytoskeletal rearrangement and cell polarity, which were correlated with the activation of focal adhesion kinase (FAK). Collectively, NgR3 is a novel indicator of poor outcomes in NPC patients and plays an important role in driving the progression of NPC. These results suggest a potential link between the nervous system and NPC progression. KEY MESSAGES: Genes involved in the neuronal biological process are enriched in nasopharyngeal carcinoma. Overexpression of NgR3 correlates with poor prognosis of nasopharyngeal carcinoma. NgR3 promotes NPC cell migration by downregulating E-cadherin. NgR3 promotes NPC cell polarity and enhances the formation of NPC cell pseudopodia by activating FAK/Src pathway.

TACC3 transcriptionally upregulates E2F1 to promote cell growth and confer sensitivity to cisplatin in bladder cancer.

Accumulating evidence has shown that transforming acidic coiled-coil 3 (TACC3) is deregulated in a broad spectrum of cancers. In the present study, we reported that TACC3 was markedly elevated in bladder cancer, especially in muscle-invasive bladder cancers (MIBCs). The upregulation of TACC3 was positively associated with tumor invasiveness, grade, T stage, and progression in patients with bladder cancer. Furthermore, a Kaplan-Meier survival analysis showed that patients with bladder cancer whose tumors had high TACC3 expression experienced a dismal prognosis compared with patients whose tumors had low TACC3 expression. Functional studies have found that TACC3 is a prerequisite for the development of malignant characteristics of bladder cancer cells, including cell proliferation and invasion. Moreover, TACC3 promoted G1/S transition, which was mediated via activation of the transcription of E2F1, eventually enhancing cell proliferation. Notably, the overexpression of TACC3 or E2F1 indicates a high sensitivity to cisplatin. Taken together, these findings define a tumor-supportive role for TACC3, which may also serve as a prognostic and therapeutic indicator in bladder cancers.

The RARS-MAD1L1 Fusion Gene Induces Cancer Stem Cell-like Properties and Therapeutic Resistance in Nasopharyngeal Carcinoma.

Purpose: Nasopharyngeal carcinoma (NPC) is the most common head and neck cancer in Southeast Asia. Because local recurrence and distant metastasis are still the main causes of NPC treatment failure, it is urgent to identify new tumor markers and therapeutic targets for advanced NPC.Experimental Design: RNA sequencing (RNA-seq) was applied to look for interchromosome translocation in NPC. PCR, FISH, and immunoprecipitation were used to examine the fusion gene expression at RNA, DNA, and protein levels in NPC biopsies. MTT assay, colony formation assay, sphere formation assay, co-immunoprecipitation, chromatin immunoprecipitation assay, and in vivo chemoresistance assay were applied to explore the function of RARS-MAD1L1 in NPC.Results: We demonstrated that RARS-MAD1L1 was present in 10.03% (35/349) primary NPC biopsies and 10.7% (9/84) in head and neck cancer (HNC) samples. RARS-MAD1L1 overexpression increased cell proliferation, colony formation, and tumorigenicity in vitro, and the silencing of endogenous RARS-MAD1L1 reduced cancer cell growth and colony formation in vitro In addition, RARS-MAD1L1 increased the side population (SP) ratio and induced chemo- and radioresistance. Furthermore RARS-MAD1L1 interacted with AIMP2, which resulted in activation of FUBP1/c-Myc pathway. The silencing of FUBP1 or the administration of a c-Myc inhibitor abrogated the cancer stem cell (CSC)-like characteristics induced by RARS-MAD1L1. The expression of c-Myc and ABCG2 was higher in RARS-MAD1L1-positive HNC samples than in negative samples.Conclusions: Our findings indicate that RARS-MAD1L1 might contribute to tumorigenesis, CSC-like properties, and therapeutic resistance, at least in part, through the FUBP1/c-Myc axis, implying that RARS-MAD1L1 might serve as an attractive target for therapeutic intervention for NPC. Clin Cancer Res; 24(3); 659-73. ©2017 AACR.

Novel chimeric transcript RRM2-c2orf48 promotes metastasis in nasopharyngeal carcinoma.

Recently, chimeric transcripts have been found to be associated with the pathogenesis and poor prognosis of malignant tumors. Through our preliminary experiment, a novel chimeric transcript called chimeric transcript RRM2-c2orf48 was detected in C666-1, a classical cell line of human nasopharyngeal carcinoma (NPC). Therefore, the objective of this study was to demonstrate the existence and expression of novel chimeric transcript RRM2-c2orf48 and to explore the main functions and mechanisms of RRM2-c2orf48 in NPC. In this study, the expression of RRM2-c2orf48 was evaluated in NPC cells and specimens. Effects of RRM2-c2orf48 on migration and invasive capacities were detected in vivo and vitro. Moreover, ways in which RRM2-c2orf48 increases the invasive capacities of NPC were explored. As a result, the presence of novel chimeric transcript RRM2-c2orf48 was confirmed in C666-1 by RT-PCR and sequencing, and it was a read-through between RRM2 and c2orf48 through the transcription of interchromosome. Higher expressions of novel RRM2-c2orf48 were detected in NPC cell lines and NPC tissue specimens relative to the controls and its expression was be statistically relevant to TNM staging. High level of RRM2-c2orf48 could increase the migration and invasive capacities of NPC cells, potentially as a result of NPC cell epithelial-mesenchymal transition. RRM2-c2orf48 could also enhance resistance of chemotherapy. In vivo, RRM2-c2orf48 could enhance lung and lymph node metastasis in nude mice. These results demonstrate that high levels of RRM2-c2orf48 expression may be a useful predictor of NPC patients of metastatic potency, presenting potential implications for NPC diagnosis and therapy.

PDZ binding kinase (PBK) is a theranostic target for nasopharyngeal carcinoma: driving tumor growth via ROS signaling and correlating with patient survival.

Nasopharyngeal carcinoma (NPC) is well known as one of the most common malignancies in southern China and Southeast Asia. However, the mechanisms underlying NPC progression remain poorly understood. Herein, through overlapping the differentially expressed genes from 3 microarray data sets with the human kinome, we identified PBK, a serine-threonine kinase, is highly upregulated and has not been intensively investigated in NPC. PBK was required for malignant phenotypes of NPC, as PBK depletion by RNAi and inhibition by specific inhibitor HI-TOPK-032 obviously reduced cell proliferation and xenograft tumor growth in mice. Moreover, we determined that targeting PBK could accelerate apoptosis by inducing ROS that activates JNK/p38 signaling pathway. In NPC patients, elevated PBK expression in primary tumor positively correlated to clinical severity such as advanced T stage, high death risk and disease progression, and it could serve as an unfavorable independent indicator of overall survival and disease-free survival. Altogether, our results indicate that PBK is a novel significant regulator of NPC progression and a potential therapeutic target for NPC patients.

ZNF488 Enhances the Invasion and Tumorigenesis in Nasopharyngeal Carcinoma Via the Wnt Signaling Pathway Involving Epithelial Mesenchymal Transition.

PURPOSE: The purpose of this study was to investigate the function of Zinc finger protein 488 (ZNF488) in nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: The endogenous expression of ZNF488 in NPC tissues, normal nasopharyngeal epithelium tissues and NPC cell lines were detected by quantitative reverse transcription polymerase chain reaction. ZNF488 over-expressing and knock-down NPC cell line models were established through retroviral vector pMSCV mediated over-expression and small interfering RNA (siRNA) mediated knock-down. The invasion and migration capacities were evaluated by wound healing and transwell invasion assays in ZNF488 over-expressing and control cell lines. Soft-agar colony formation and a xenograft experiment were performed to study tumorigenic ability in vitro and in vivo. Immunofluorescence and western blotting analysis were used to examine protein changes followed by ZNF488 over-expression. Microarray analysis was performed to explore gene expression profilings, while luciferase reporter assay to evaluate the transcriptive activity of Tcf/Lef. RESULTS: ZNF488 was over-expressed in NPC tissues compared with normal tissues, especially higher in 5-8F and S18, which are well-established high metastatic NPC clones. Functional studies indicate that over-expression of ZNF488 provokes invasion, whereas knock-down of ZNF488 alleviates invasive capability. Moreover, over-expression of ZNF488 promotes NPC tumor growth both in vitro and in vivo. Our data further show that over-expression of ZNF488 induces epithelial mesenchymal transition (EMT) by activating the WNT/ß-catenin signaling pathway. CONCLUSION: Our data strongly suggest that ZNF488 acts as an oncogene, promoting invasion and tumorigenesis by activating the Wnt/ß-catenin pathway to induce EMT in NPC.

High expression of transforming acidic coiled coil-containing protein 3 strongly correlates with aggressive characteristics and poor prognosis of gastric cancer.

Transforming acidic coiled coil-containing protein 3 (TACC3) is well understood to regulate mitotic spindle dynamics and centrosome integrity during mitosis. TACC3 has been suggested to be deregulated in a variety of human malignancies and may be involved in the process of cancer progression. The aim of the present study was to determine the status of TACC3 expression in gastric cancer (GC) and to clarify its clinical/prognostic significance. In the present study, we applied quantitative PCR (qPCR) and western blotting to examine TACC3 mRNA/protein expression in paired GC tissues and matched adjacent non-malignant tissues. Immunohistochemistry (IHC) was performed on a large cohort of 186 postoperative GC samples. Chi-square test, Kaplan-Meier analysis and Cox regression modelling were used to analyse the data. Upregulated mRNA and protein expression levels of TACC3 were observed in the majority of the GC tissues based on qPCR and western blotting compared to the adjacent non-cancerous gastric tissues. Specific IHC staining for TACC3 was predominantly identified in the cytoplasm of the cancer cells. A high expression of TACC3 was detected in 102 of the 186 (54.8%) tissue samples and was significantly associated with the extracapsular extension of the tumour (P<0.001), tumour relapse (P<0.001) and shortened overall survival in GC (P<0.001). Further analysis demonstrated that the TACC3 expression level stratified the patient outcome in stage II (P=0.040), stage III (P<0.001), T3/4 (P<0.001), N positive (P<0.001) and poorly differentiated/undifferentiated tumour subgroups (P<0.001). The Cox regression analysis suggested that a high expression of TACC3 was an independent prognostic factor for GC patients. The measurement of TACC3 protein expression may be beneficial for predicting clinical outcomes for GC patients.

High expression of TACC3 in esophageal squamous cell carcinoma correlates with poor prognosis.

To analyze the expression of the transforming acidic coiled-coil protein 3 (TACC3) in esophageal squamous cell carcinoma (ESCC) samples, and to identify whether TACC3 can serve as a biomarker for the diagnosis and prognosis of ESCC, qPCR, western blotting and immunohistochemistry staining (IHC) were utilized to detect the expression of TACC3. Furthermore, cell growth, colony formation, migration ability and the epithelial-mesenchymal transition markers of ESCC cells in which TACC3 were knocked-down were measured. The mRNA and protein levels of TACC3 were higher in ESCC specimens compared to non-tumorous esophageal epithelial tissues. IHC results revealed TACC3 expression was significantly correlated to differentiation (p = 0.017) and lymphoid nodal status (p = 0.028). The patients with high-expression of TACC3 had a significantly poor prognosis compared to those of low-expression (p = 0.017), especially in the patients at stages I-II (p = 0.028). Multivariate analysis indicated that TACC3 expression was an independent prognostic factor for ESCC patients (p = 0.025). Knockdown of TACC3 inhibited the ability of cell proliferation, colony formation and migration. This study first identifies TACC3 not only as a useful biomarker for diagnose and prognosis of ESCC, but also as a potential therapeutic target for patients with ESCC.

Ribonucleotide reductase M2 subunit expression and prognostic value in nasopharyngeal carcinoma.

The ribonucleotide reductase M2 subunit (RRM2) modulates the enzymatic activity of ribonucleotide reductase, and is involved in tumor progression. Recently, high levels of RRM2 expression were reported to correlate with poor survival outcomes in patients with colorectal and bladder cancer. However, changes in RRM2 expression in nasopharyngeal carcinoma (NPC), and its effect on the prognosis of this disease remain unknown. The aim of the present study was to analyze the expression of RRM2 in NPC cell lines, and to identify whether RRM2 may serve as a biomarker with which to assess the prognosis of NPC. The present study found that RRM2 expression was higher in NPC cell lines and tissue samples than in noncancerous nasopharyngeal epithelial cell lines and noncancerous tissues, as shown by reverse transcription-quantitative polymerase chain reaction analysis, western blotting and immunohistochemistry staining. Kaplan-Meier survival analysis demonstrated that patients with higher RRM2 expression levels had poorer disease-free survival outcomes than those with lower expression levels of RRM2. Univariate analysis showed that a lower survival rate was significantly associated with high RRM2 expression levels [hazard ratio (HR), 6.424; 95% confidence interval (CI), 2.381-17.333; P<0.001]. Multivariate analysis indicated that RRM2 expression is an independent prognostic factor for patients with NPC (HR, 3.461; 95 % CI, 1.204-9.949; P=0.021). Overexpression of RRM2 led to increased cell proliferation, colony formation, migration and invasion in vivo. These results suggest that high levels of RRM2 expression may be a useful predictor for survival in patients with NPC and may serve as a novel prognostic indicator for these individuals.

Recurrent FGFR3-TACC3 fusion gene in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is one of the most common head and neck malignancies and exhibits regional differences in incidence. Because many fusion genes have been discovered in different types of tumors over the past few years, we aimed to investigate the existence of a fusion gene in primary NPC patients using RNA-seq. In this study, for the first time, we found that fibroblast growth factor receptor 3-transforming acidic coiled-coil-containing protein 3 (FGFR3-TACC3) fusion transcripts are recurrently detected in NPC. The presence of this fusion gene was also detected in head and neck cancer, esophageal squamous cell carcinoma (ESCC), and lung cancer. Furthermore, we found certain new isoforms of the FGFR3-TACC3 fusion transcripts, such as a gene fusion between exon 18 of FGFR3 and exon 6 or exon 14 of TACC3 and agene fusion between exon 19 of FGFR3 and exon 11 of TACC3. In addition, we showed that the FGFR3-TACC3 fusion gene promotes cell proliferation, colony formation, and transforming ability in vitro, whereas the FGFR3-TACC3 K508M mutant or treatment with the FGFR inhibitor PD173074 abrogates these effects, suggesting that FGFR3-TACC3 most likely exerts its effects through activation of FGFR kinase activity. This activation likely leads to the development of NPC. Additionally, FGFR3-TACC3 could trigger activation of the ERK and Akt signaling pathways, whereas FGFR3-TACC3 K508M mutant could not, suggesting that these 2 signaling pathways might be involved in the function of FGFR3-TACC3. Taken together, our data demonstrated the oncogenic role of FGFR3-TACC3 in vitro, indicating that FGFR3-TACC3 may be useful as a diagnostic marker and therapeutic target in cancers.

Protein tyrosine kinase 6 is associated with nasopharyngeal carcinoma poor prognosis and metastasis.

BACKGROUND: The aim of this study was to analyze the expression of protein tyrosine kinase 6 (PTK6) in nasopharyngeal carcinoma (NPC) samples, and to identify whether PTK6 can serve as a biomarker for the diagnosis and prognosis of NPC. METHODS: We used quantitative RT-PCR and Western blotting analysis to detect mRNA and protein expression of PTK6 in NPC cell lines and immortalized nasopharyngeal epithelial cell lines. 31 NPC and 16 non-tumorous nasopharyngeal mucosa biopsies were collected to detect the difference in the expression of mRNA level of PTK6 by quantitative RT-PCR. We also collected 178 NPC and 10 normal nasopharyngeal epithelial cases with clinical follow-up data to investigate the expression of PTK6 by immunohistochemistry staining (IHC). PTK6 overexpression on cell growth and colony formation ability were measured by the method of cell proliferation assay and colony formation assay. RESULTS: The expression of PTK6 was higher in most of NPC cell lines at both mRNA and protein levels than in immortalized nasopharyngeal epithelial cell lines (NPECs) induced by Bmi-1 (Bmi-1/NPEC1, and Bmi-1/NPEC2). The mRNA level of PTK6 was high in NPC biopsies compared to non-tumorous nasopharyngeal mucosa biopsies. IHC results showed the expression of PTK6 was significantly correlated to tumor size (P<0.001), clinical stage (P<0.001), and metastasis (P=0.016). The patients with high-expression of PTK6 had a significantly poor prognosis compared to those of low-expression (47.8% versus 80.0%, P<0.001), especially in the patients at the advanced stages (42.2% versus 79.1%, P<0.001). Multivariate analysis indicated that the level of PTK6 expression was an independent prognostic factor for the overall survival of patients with NPC (P <0.001). Overexpression of PTK6 in HNE1 cells enhanced the ability of cell proliferation and colony formation. CONCLUSIONS: Our results suggest that high-expression of PTK6 is an independent factor for NPC patients and it might serve as a potential prognostic biomarker for patients with NPC.

Low expression of PTK6/Brk predicts poor prognosis in patients with laryngeal squamous cell carcinoma.

BACKGROUND: Protein tyrosine kinase 6 (PTK6), also known as breast tumor kinase (Brk), was a nonreceptor tyrosine kinase containing SH3, SH2, and tyrosine kinase catalytic domains. The deregulated expression of PTK6 was observed in various human cancers. However, little was known about PTK6 expression and its clinicopathological significance in human laryngeal squamous cell carcinoma (LSCC). MATERIALS: PTK6 expression was evaluated in 7 pairs of surgically resectable laryngeal tissues by Western blotting and in 13 pairs of surgically resectable laryngeal tissues by reverse transcription-PCR (RT-PCR). Using immunohistochemistry, we performed a retrospective study of the PTK6 expression levels on 134 archival LSCC paraffin-embedded samples. Prognostic outcomes correlated with PTK6 were examined using Kaplan-Meier analysis and Cox proportional hazards model. RESULTS: The PTK6 expression level was lower in LSCC tissues than in the adjacent noncancerous epithelial laryngeal tissues by Western blots and RT-PCR. By immunohistochemical analysis, we observed high expression of PTK6 in 25 of 76 (32.9%) adjacent noncancerous epithelial laryngeal tissues and in 39 of 134 (29.1%) of LSCC, respectively. Multivariate analysis demonstrated that pN status and the expression level of PTK6 (P < 0.05) were independent and significant prognostic factors. In the primary LSCC category, median DFS (disease free survival) of high, medium and low PTK6 expression patients were 88.5 months ,74.5 months and 49.0 months (log-rank test, P = 0.002); median OS (overall survival) of high, medium and low PTK6 expression patients were 88.5 months ,76.3 months and 65.7 months (log-rank test, P = 0.002). Reduced cytoplasmic PTK6 expression in LSCC was significantly associated with late pN status (P =0.005, r = 0.27), advanced pTNM stages (III and IV) (P =0.027, r = 0.147), and poor differentiated LSCC (P <0.0001, r = 0.486). In adjacent paracancerous laryngeal epithelial samples, median DFS of high, medium and low PTK6 expression patients were 92.6 months ,75.6 months and 48.5 months (log-rank test, P = 0.020); median OS of high, medium and low PTK6 expression patients were 92.9 months ,78.9 months and 74.6 months (log-rank test, P = 0.042). CONCLUSION: The present findings indicated that cytoplasmic PTK6 expression is a potential prognostic factor for survival in LSCC patients. High expression of PTK6 was associated with favorable OS and DFS in LSCC patients.