Maria Lung - Academia.edu (original) (raw)

Papers by Maria Lung

Proceedings of the National Academy of Sciences of the United States of America, Oct 19, 2016

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy with a unique geographical distributio... more Nasopharyngeal carcinoma (NPC) is an epithelial malignancy with a unique geographical distribution. The genomic abnormalities leading to NPC pathogenesis remain unclear. In total, 135 NPC tumors were examined to characterize the mutational landscape using whole-exome sequencing and targeted resequencing. An APOBEC cytidine deaminase mutagenesis signature was revealed in the somatic mutations. Noticeably, multiple loss-of-function mutations were identified in several NF-κB signaling negative regulators NFKBIA, CYLD, and TNFAIP3 Functional studies confirmed that inhibition of NFKBIA had a significant impact on NF-κB activity and NPC cell growth. The identified loss-of-function mutations in NFKBIA leading to protein truncation contributed to the altered NF-κB activity, which is critical for NPC tumorigenesis. In addition, somatic mutations were found in several cancer-relevant pathways, including cell cycle-phase transition, cell death, EBV infection, and viral carcinogenesis. These da...

Cancer Research

Background: Patient-derived xenograft has been a gold standard for cancer modeling. However, low ... more Background: Patient-derived xenograft has been a gold standard for cancer modeling. However, low establishment efficiency and high maintenance cost have hindered the development in the field. In recent years, patient-derived tumor organoid culture has been developed as an efficient and economic model to mimic and recapitulate the original tumor tissue, in contrast to conventional cancer cell lines and patient-derived xenografts (Drost & Clevers, 2018). Due to the limited availability of current esophageal squamous cell carcinoma (ESCC) models, we aimed to establish a panel of ESCC patient-derived organoid (PDO) long-term cultures for ESCC study. Results: In the current project, we have established and biobanked a panel of ESCC PDO cultures in vitro from Chinese ESCC treatment-naïve patients undergoing an endoscopic examination or upfront surgery, or patients undergoing neoadjuvant chemoradiotherapy (CRT) followed by surgery in Hong Kong. We also established and maintained PDO-derive...

Cancer Research

Esophageal squamous cell carcinoma (ESCC) is highly prevalent in Asia with a poor prognosis and a... more Esophageal squamous cell carcinoma (ESCC) is highly prevalent in Asia with a poor prognosis and a high mortality rate [1, 2]. The p63 protein, encoded by TP63, is a master regulator involved in many cell events including cell cycle, DNA damage, cell proliferation, stem cell maintenance, and cell death in different cancer types. ΔNp63α is the dominantly expressed isoform of p63 in squamous cell carcinomas, playing a critical role in tumorigenesis [3, 4]. However, the functional roles of ΔNp63α in ESCC have not been fully elucidated. Our results have revealed that ΔNp63α is highly expressed and up-regulated in ESCC. We have shown that ΔNp63α protein expression plays an oncogenic role in ESCC cells, depletion of which inhibits in vitro cell proliferation and colony formation and greatly suppresses in vivo tumor growth, in a panel of ESCC cell lines and our latest patient-derived organoid cultures, potentially in a differentiation-dependent manner. Glycolysis pathway and two novel downs...

Journal of Clinical Microbiology, 1989

Under stringent hybridization conditions, cDNA of segment 9 of the rotavirus genome, which codes ... more Under stringent hybridization conditions, cDNA of segment 9 of the rotavirus genome, which codes for the viral protein VP7, permitted differentiation of serotypes of culture-grown rotaviruses and natural isolates of human rotaviruses directly from clinical specimens. This was evident for the following reasons. (i) The cDNA of one serotype selectively hybridized with the RNA of the same serotype of culture-grown rotaviruses. (ii) Natural isolates of the virus thus identified as serotype 2 were also those which gave the short electrophoretic pattern characteristic of the genome of serotype 2, subgroup 1 viruses. Isolates having the long electrophoretic pattern characteristic of the genome of subgroup 2 viruses were identified as serotype 1, 3, or 4 by this method. (iii) For patients who had previously undergone serological analysis, the serotypes being excreted were the same serotypes against which there was the most marked serum neutralizing antibody response. Although the virus popu...

Biosensors and Their Applications, 2000

19 Rapid Measurement of Biodegradable Substances in Water Using Novel Microbial Sensors Reinhard ... more 19 Rapid Measurement of Biodegradable Substances in Water Using Novel Microbial Sensors Reinhard Renneberg, Alex WK Kwong, Chiyui Chan, Gotthard Kunze, Maria L. Lung, and Klaus Riedel 19.1. INTRODUCTION Microbial sensors based on microorganisms in direct ...

Tumor Suppressor Genes, 2012

Loss of DNA or chromosomal deletion was frequently reported in different sporadic tumors, suggest... more Loss of DNA or chromosomal deletion was frequently reported in different sporadic tumors, suggesting that those lost regions may contain putative tumor suppressor genes (TSGs). To map and isolate candidate genes from vast randomly lost areas, functional and complementary evidence is usually needed to define these areas to critical regions (CR). This is particularly important when one is dealing with sporadic cancers where clearly defined familial predisposition is present but high cancer risk families are not available for position cloning. A numerous studies have revealed extensive DNA deletions in nasopharyngeal carcinoma (NPC) and esophageal squamous cell carcinoma (ESCC). To identify candidate genes from these cancers, we used cell fusion and microcell-mediated chromosome transfer (MMCT) to introduce the whole chromosome or a chromosome fragment, into NPC and ESCC cell lines. Combined with other molecular approaches, we have successfully identified a number of novel TSGs on various human chromosomes. The nasopharynx is located behind the nasal cavity in the upper part of the pharynx (Fig. 1). NPC is a type of malignancy which arises from the epithelial cells in the nasopharynx. NPC is an unique cancer, which is commonly found in, Southeast Asia, North Africa, Middle East, and Arctic regions, but rare in most parts of the world (Jeyakumar et al 2006, Wei et al 2005). The esophagus is a tube, which is about 25 cm long, for the food passage from mouth to stomach (Fig. 2). Esophageal cancer (EC) is classified into two major histologic subtypes: squamous cell carcinoma and adenocarcinoma (Daly et al 2000). Esophageal adenocarcinoma (EAC) arises from the cells of glands responsible for producing mucous in the esophageal wall. The majority of the cases (>80%) are ESCC in Hong Kong, while EAC shows a climbing incidence in Western countries. EC varies greatly in geographical distribution; high-risk areas include north-central China in Henan and Shanxi (Holmes et al 2007, Qi et al 2005, Wu et al 2006). 2. Chromosome transfer in tumor studies 2.1 Somatic cell fusion and tumor suppression The theory for specific chromosomes contributing to tumor suppression was originally proven by somatic cell genetics (Harris et al 1969). In their study, Harris and colleagues fused the www.

Future Aspects of Tumor Suppressor Gene, 2013

PLoS ONE, 2013

Nasopharyngeal carcinoma (NPC) is etiologically associated with Epstein-Barr virus (EBV) infectio... more Nasopharyngeal carcinoma (NPC) is etiologically associated with Epstein-Barr virus (EBV) infection. However, the exact role of EBV in NPC pathogenesis remains elusive. Activation of signal transducer and activator of transcription 3 (STAT3) is common in human cancers including NPC and plays an important role in the pathogenesis and progression of human cancers. Interleukin-6 (IL-6), a major inflammatory cytokine, is a potent activator of STAT3. In this study, we report that EBVinfected immortalized nasopharyngeal epithelial (NPE) cells often acquire an enhanced response to IL-6-induced STAT3 activation to promote their growth and invasive properties. Interestingly, this enhanced IL-6/STAT3 response was mediated by overexpression of IL-6 receptor (IL-6R). Furthermore, IL-6R overexpression enhanced IL-6-induced STAT3 activation in uninfected immortalized NPE cells in vitro, and promoted growth and tumorigenicity of EBV-positive NPC cell line (C666-1) in vivo. Moreover, it is shown for the first time that IL-6R was overexpressed in clinical specimens of NPC. IL-6 expression could also be strongly detected in the stromal cells of NPC and a higher circulating level of IL-6 was found in the sera of advance-staged NPC patients compared to the control subjects. Therefore, IL-6R overexpression, coupled with enhanced IL-6/STAT3 signaling may facilitate the malignant transformation of EBV-infected premalignant NPE cells into cancer cells, and enhance malignant properties of NPC cells.

Oncogene, 2011

Fibulin-2 (FBLN2) has been identified as a candidate tumor-suppressor gene in nasopharyngeal carc... more Fibulin-2 (FBLN2) has been identified as a candidate tumor-suppressor gene in nasopharyngeal carcinoma (NPC). Originally identified through a chromosome 3 NotI genomic microarray screen, it shows frequent deletion or methylation in NPC. FBLN2 is located on chromosome 3p25.1 and is associated with tumor development through its important interactions with the extracellular matrix (ECM) proteins. FBLN2 encodes two isoforms. The short isoform (FBLN2S) is expressed abundantly in normal tissues, but is dramatically downregulated in NPC, while the long isoform (FBLN2L) is either not detectable or is expressed only at low levels in both normal and tumor tissues. Reintroduction of this FBLN2S inhibited cell proliferation, migration, invasion and angiogenesis in vitro. Furthermore, in vivo studies in nude mice show its expression is associated with tumor and angiogenesis suppression. FBLN2-associated angiogenesis occurs via concomitant downregulation of vascular endothelial growth factor and matrix metalloproteinase 2. This study provides compelling evidence that FBLN2S has an important tumor-suppressive and anti-angiogenic role in NPC.

Journal of Cellular Biochemistry, 2009

Epidermal growth factor receptor (EGFR), a receptor often expressed in nasopharyngeal carcinoma (... more Epidermal growth factor receptor (EGFR), a receptor often expressed in nasopharyngeal carcinoma (NPC) cells, is one of the recently identified molecular targets in cancer treatment. In the present study, the effects of combined treatment of Zn-BC-AM PDT with an EGFR inhibitor AG1478 were investigated. Well-differentiated NPC HK-1 cells were subjected to PDT with 1 mM of Zn-BC-AM and were irradiated at a light dose of 1 J/cm 2 in the presence or absence of EGFR inhibitor AG1478. Specific protein kinase inhibitors of downstream EGFR targets were also used in the investigation. EGFR, Akt, and ERK were found constitutively activated in HK-1 cells and the activities could be inhibited by the EGFR inhibitor AG1478. A sub-lethal concentration of AG1478 was found to further enhance the irreversible cell damage induced by Zn-BC-AM PDT in HK-1 cells. Pre-incubation of the cells with specific inhibitors of EGFR (AG1478), PI3k/Akt (LY294002), or MEK/ERK (PD98059) before light irradiation were found to enhance Zn-BC-AM PDT-induced formation of apoptotic cells. The efficacy of Zn-BC-AM PDT can be increased through the inhibition of EGFR/PI3K/Akt and EGFR/MEK/ERK signaling pathways in NPC cells. Combination therapy with Zn-BC-AM PDT and EGFR inhibitors may further be developed for the treatment of advanced NPC.

Cell Biochemistry and Function, 2010

Photodynamic therapy (PDT) with a recently developed photosensitizer Zn-BC-AM was found to effect... more Photodynamic therapy (PDT) with a recently developed photosensitizer Zn-BC-AM was found to effectively induce apoptosis in a welldifferentiated nasopharyngeal carcinoma (NPC) HK-1 cell line. Sustained activation of p38 mitogen-activated protein kinase (MAPK) and cjun N-terminal kinase (JNK) as well as a transient increase in activation of extracellular-regulated kinase (ERK) were observed immediately after Zn-BC-AM PDT. A commonly used p38 MAPK/JNK pharmacological inhibitor PD169316 was found to reduce PDT-induced apoptosis of HK-1 cells. PD169316 also prevented the loss of Bcl-2 and Bcl-xL in PDT-treated HK-1 cells. However, inhibition of JNK with SP600125 had no effect on Zn-BC-AM PDT-induced apoptosis while inhibition of ERK with PD98059 or p38 MAPK with SB203580 significantly increased Zn-BC-AM PDT-induced apoptosis. Further study showed that knockdown of the p38b isoform with siRNA also increased Zn-BC-AM PDT-induced apoptosis, indicating that the anti-apoptotic effect of PD169316 in PDT-treated HK-1 cells was probably independent of p38 MAPK or JNK activation. Taken together, the results suggest that inhibition of p38b and ERK may enhance the therapeutic efficacy of Zn-BC-AM PDT on NPC cells. It should be noted that data only based on the use of PD169316 should be interpreted in caution.

Biosensors and Bioelectronics, 1999

A microbial biosensor based on the yeast Arxula adeninivorans LS3 has been developed for measurem... more A microbial biosensor based on the yeast Arxula adeninivorans LS3 has been developed for measurement of biodegradable substances. Arxula is immobilized in the hydrogel poly(carbamoyl) sulfonate (PCS). The immobilized yeast membrane is placed in front of an oxygen electrode with Ϫ 600 mV versus Ag/AgCl. Arxula is salt tolerant; it can give a stable signal up to 2.5 M NaCl in sample (120 mM in measuring cell). The sensor's measurements are highly correlated to BOD 5 measurements. It has a very high stability which can last for 40 days without any decrease in signal. The linear range of the sensor is up to a corresponding BOD value of 550 mg/l.

The key genes involved in the development of esophageal squamous cell carcinoma (ESCC) remain to ... more The key genes involved in the development of esophageal squamous cell carcinoma (ESCC) remain to be elucidated. Previous studies indicate extensive genomic alterations occur on chromosome 9 in ESCC. Using a monochromosome transfer approach, this study provides functional evidence and narrows down the critical region (CR) responsible for chromosome 9 tumor suppressing activity to a 2.4 Mb region mapping to 9q33–q34 between markers D9S1798 and D9S61. Interestingly, a high prevalence of allelic loss in this CR is also observed in primary ESCC tumors by microsatellite typing. Allelic loss is found in 30/34 (88%) tumors and the loss of heterozygosity (LOH) frequency ranges from 67 to 86%. Absent to low expression of a 9q32 candidate tumor suppressor gene (TSG), DEC1 (deleted in esophageal cancer 1), is detected in four Asian ESCC cell lines. Stably expressing DEC1 transfectants provide functional evidence for inhibition of tumor growth in nude mice and DEC1 expression is decreased in tum...

In many cancers, including nasopharyngeal carcinoma (NPC), extensive and multiple regions of alle... more In many cancers, including nasopharyngeal carcinoma (NPC), extensive and multiple regions of allelic loss occur on chromosome 14. However, to date no functionally conclusive tumor suppressor genes have yet been identified on this chromosome. Through use of the monochromosome transfer technique, this study provides functional evidence for the importance of two discrete regions of chromosome 14. A newly established A9 mouse donor cell line containing an intact copy of chromosome 14 was used for transfer of this intact chromosome into the NPC HONE1 cell line. Twelve independently established microcell hybrids demonstrated uniform loss of specific chromosome 14 loci from both endogenous and exogenous alleles. By microsatellite typing and fluorescence in situ hybridization with BAC probes, the two critical regions were localized to 14q11.2–13.1 and 14q32.1. Selective elimination of these regions during hybrid selection was strongly associated with both hybrid survival and tumor growth in...

Orthotopic xenograft model recapitulates the faithful organ-specific microenvironment and facilit... more Orthotopic xenograft model recapitulates the faithful organ-specific microenvironment and facilitates analyses involving tumor-stromal interactions that are crucial for developing new-generation cancer therapy. Herein, we describe the detailed rationales and protocols of a versatile orthotopic xenograft model for esophageal squamous cell carcinoma.

Advanced Science

Germline polymorphisms are linked with differential survival outcomes in cancers but are not well... more Germline polymorphisms are linked with differential survival outcomes in cancers but are not well studied in nasopharyngeal carcinoma (NPC). Here, a two-phase association study is conducted to discover germline polymorphisms that are associated with the prognosis of NPC. The discovery phase includes two consecutive hospital cohorts of patients with NPC from Southern China. Exome-wide genotypes at 246 173 single nucleotide polymorphisms (SNPs) are determined, followed by survival analysis for each SNP under Cox proportional hazard regression model. Candidate SNP is replicated in another two independent cohorts from Southern China and Singapore. Meta-analysis of all samples (n = 5553) confirms that the presence of rs1131636-T, located in the 3′-UTR of RPA1, confers an inferior overall survival (HR = 1.33, 95% CI = 1.20-1.47, P = 6.31 × 10 −8). Bioinformatics and biological assays show that rs1131636 has regulatory effects on upstream RPA1. Functional studies further demonstrate that RPA1 promotes the growth, invasion, migration, and radioresistance of NPC cells. Additionally, miR-1253 is identified as a suppressor for RPA1 expression, likely through regulation of its binding affinity to rs1131636 locus. Collectively, these findings provide a promising biomarker aiding in stratifying patients with poor survival, as well as a potential drug target for NPC.

Molecular and Cellular Biology / Genetics

International journal of cancer, Jan 4, 2018

Nasopharyngeal carcinoma is an Epstein-Barr Virus (EBV) associated malignancy which is highly pre... more Nasopharyngeal carcinoma is an Epstein-Barr Virus (EBV) associated malignancy which is highly prevalent in Southeast Asia. EBV-related antibodies have been widely used as screening markers for early nasopharyngeal carcinoma (NPC) detection. However, due to low positive predictive rate, it is essential to develop new biomarkers to facilitate NPC early diagnosis or triage EBV serological high-risk individuals to improve the chance of NPC early detection. BART microRNAs, which are encoded by BamHI region of EBV, were reported to be abundant in NPC and have potential value in early diagnosis of NPC. Here, we quantified the circulating level of 17 BART microRNAs in discovery stage based on previous microarray and sequencing data and, in particular, BART 2-5p, the sole candidate whose AUC was higher than 0.8, has been chosen for further study. In validation stage, the sensitivity, specificity and AUC of BART 2-5p was 93.9%, 89.8%, 0.972(95%CI: 0.954-0.989) respectively in cohort 1 constit...

Proceedings of the National Academy of Sciences of the United States of America, Oct 19, 2016

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy with a unique geographical distributio... more Nasopharyngeal carcinoma (NPC) is an epithelial malignancy with a unique geographical distribution. The genomic abnormalities leading to NPC pathogenesis remain unclear. In total, 135 NPC tumors were examined to characterize the mutational landscape using whole-exome sequencing and targeted resequencing. An APOBEC cytidine deaminase mutagenesis signature was revealed in the somatic mutations. Noticeably, multiple loss-of-function mutations were identified in several NF-κB signaling negative regulators NFKBIA, CYLD, and TNFAIP3 Functional studies confirmed that inhibition of NFKBIA had a significant impact on NF-κB activity and NPC cell growth. The identified loss-of-function mutations in NFKBIA leading to protein truncation contributed to the altered NF-κB activity, which is critical for NPC tumorigenesis. In addition, somatic mutations were found in several cancer-relevant pathways, including cell cycle-phase transition, cell death, EBV infection, and viral carcinogenesis. These da...

Cancer Research

Background: Patient-derived xenograft has been a gold standard for cancer modeling. However, low ... more Background: Patient-derived xenograft has been a gold standard for cancer modeling. However, low establishment efficiency and high maintenance cost have hindered the development in the field. In recent years, patient-derived tumor organoid culture has been developed as an efficient and economic model to mimic and recapitulate the original tumor tissue, in contrast to conventional cancer cell lines and patient-derived xenografts (Drost & Clevers, 2018). Due to the limited availability of current esophageal squamous cell carcinoma (ESCC) models, we aimed to establish a panel of ESCC patient-derived organoid (PDO) long-term cultures for ESCC study. Results: In the current project, we have established and biobanked a panel of ESCC PDO cultures in vitro from Chinese ESCC treatment-naïve patients undergoing an endoscopic examination or upfront surgery, or patients undergoing neoadjuvant chemoradiotherapy (CRT) followed by surgery in Hong Kong. We also established and maintained PDO-derive...

Cancer Research

Esophageal squamous cell carcinoma (ESCC) is highly prevalent in Asia with a poor prognosis and a... more Esophageal squamous cell carcinoma (ESCC) is highly prevalent in Asia with a poor prognosis and a high mortality rate [1, 2]. The p63 protein, encoded by TP63, is a master regulator involved in many cell events including cell cycle, DNA damage, cell proliferation, stem cell maintenance, and cell death in different cancer types. ΔNp63α is the dominantly expressed isoform of p63 in squamous cell carcinomas, playing a critical role in tumorigenesis [3, 4]. However, the functional roles of ΔNp63α in ESCC have not been fully elucidated. Our results have revealed that ΔNp63α is highly expressed and up-regulated in ESCC. We have shown that ΔNp63α protein expression plays an oncogenic role in ESCC cells, depletion of which inhibits in vitro cell proliferation and colony formation and greatly suppresses in vivo tumor growth, in a panel of ESCC cell lines and our latest patient-derived organoid cultures, potentially in a differentiation-dependent manner. Glycolysis pathway and two novel downs...

Journal of Clinical Microbiology, 1989

Under stringent hybridization conditions, cDNA of segment 9 of the rotavirus genome, which codes ... more Under stringent hybridization conditions, cDNA of segment 9 of the rotavirus genome, which codes for the viral protein VP7, permitted differentiation of serotypes of culture-grown rotaviruses and natural isolates of human rotaviruses directly from clinical specimens. This was evident for the following reasons. (i) The cDNA of one serotype selectively hybridized with the RNA of the same serotype of culture-grown rotaviruses. (ii) Natural isolates of the virus thus identified as serotype 2 were also those which gave the short electrophoretic pattern characteristic of the genome of serotype 2, subgroup 1 viruses. Isolates having the long electrophoretic pattern characteristic of the genome of subgroup 2 viruses were identified as serotype 1, 3, or 4 by this method. (iii) For patients who had previously undergone serological analysis, the serotypes being excreted were the same serotypes against which there was the most marked serum neutralizing antibody response. Although the virus popu...

Biosensors and Their Applications, 2000

19 Rapid Measurement of Biodegradable Substances in Water Using Novel Microbial Sensors Reinhard ... more 19 Rapid Measurement of Biodegradable Substances in Water Using Novel Microbial Sensors Reinhard Renneberg, Alex WK Kwong, Chiyui Chan, Gotthard Kunze, Maria L. Lung, and Klaus Riedel 19.1. INTRODUCTION Microbial sensors based on microorganisms in direct ...

Tumor Suppressor Genes, 2012

Loss of DNA or chromosomal deletion was frequently reported in different sporadic tumors, suggest... more Loss of DNA or chromosomal deletion was frequently reported in different sporadic tumors, suggesting that those lost regions may contain putative tumor suppressor genes (TSGs). To map and isolate candidate genes from vast randomly lost areas, functional and complementary evidence is usually needed to define these areas to critical regions (CR). This is particularly important when one is dealing with sporadic cancers where clearly defined familial predisposition is present but high cancer risk families are not available for position cloning. A numerous studies have revealed extensive DNA deletions in nasopharyngeal carcinoma (NPC) and esophageal squamous cell carcinoma (ESCC). To identify candidate genes from these cancers, we used cell fusion and microcell-mediated chromosome transfer (MMCT) to introduce the whole chromosome or a chromosome fragment, into NPC and ESCC cell lines. Combined with other molecular approaches, we have successfully identified a number of novel TSGs on various human chromosomes. The nasopharynx is located behind the nasal cavity in the upper part of the pharynx (Fig. 1). NPC is a type of malignancy which arises from the epithelial cells in the nasopharynx. NPC is an unique cancer, which is commonly found in, Southeast Asia, North Africa, Middle East, and Arctic regions, but rare in most parts of the world (Jeyakumar et al 2006, Wei et al 2005). The esophagus is a tube, which is about 25 cm long, for the food passage from mouth to stomach (Fig. 2). Esophageal cancer (EC) is classified into two major histologic subtypes: squamous cell carcinoma and adenocarcinoma (Daly et al 2000). Esophageal adenocarcinoma (EAC) arises from the cells of glands responsible for producing mucous in the esophageal wall. The majority of the cases (>80%) are ESCC in Hong Kong, while EAC shows a climbing incidence in Western countries. EC varies greatly in geographical distribution; high-risk areas include north-central China in Henan and Shanxi (Holmes et al 2007, Qi et al 2005, Wu et al 2006). 2. Chromosome transfer in tumor studies 2.1 Somatic cell fusion and tumor suppression The theory for specific chromosomes contributing to tumor suppression was originally proven by somatic cell genetics (Harris et al 1969). In their study, Harris and colleagues fused the www.

Future Aspects of Tumor Suppressor Gene, 2013

PLoS ONE, 2013

Nasopharyngeal carcinoma (NPC) is etiologically associated with Epstein-Barr virus (EBV) infectio... more Nasopharyngeal carcinoma (NPC) is etiologically associated with Epstein-Barr virus (EBV) infection. However, the exact role of EBV in NPC pathogenesis remains elusive. Activation of signal transducer and activator of transcription 3 (STAT3) is common in human cancers including NPC and plays an important role in the pathogenesis and progression of human cancers. Interleukin-6 (IL-6), a major inflammatory cytokine, is a potent activator of STAT3. In this study, we report that EBVinfected immortalized nasopharyngeal epithelial (NPE) cells often acquire an enhanced response to IL-6-induced STAT3 activation to promote their growth and invasive properties. Interestingly, this enhanced IL-6/STAT3 response was mediated by overexpression of IL-6 receptor (IL-6R). Furthermore, IL-6R overexpression enhanced IL-6-induced STAT3 activation in uninfected immortalized NPE cells in vitro, and promoted growth and tumorigenicity of EBV-positive NPC cell line (C666-1) in vivo. Moreover, it is shown for the first time that IL-6R was overexpressed in clinical specimens of NPC. IL-6 expression could also be strongly detected in the stromal cells of NPC and a higher circulating level of IL-6 was found in the sera of advance-staged NPC patients compared to the control subjects. Therefore, IL-6R overexpression, coupled with enhanced IL-6/STAT3 signaling may facilitate the malignant transformation of EBV-infected premalignant NPE cells into cancer cells, and enhance malignant properties of NPC cells.

Oncogene, 2011

Fibulin-2 (FBLN2) has been identified as a candidate tumor-suppressor gene in nasopharyngeal carc... more Fibulin-2 (FBLN2) has been identified as a candidate tumor-suppressor gene in nasopharyngeal carcinoma (NPC). Originally identified through a chromosome 3 NotI genomic microarray screen, it shows frequent deletion or methylation in NPC. FBLN2 is located on chromosome 3p25.1 and is associated with tumor development through its important interactions with the extracellular matrix (ECM) proteins. FBLN2 encodes two isoforms. The short isoform (FBLN2S) is expressed abundantly in normal tissues, but is dramatically downregulated in NPC, while the long isoform (FBLN2L) is either not detectable or is expressed only at low levels in both normal and tumor tissues. Reintroduction of this FBLN2S inhibited cell proliferation, migration, invasion and angiogenesis in vitro. Furthermore, in vivo studies in nude mice show its expression is associated with tumor and angiogenesis suppression. FBLN2-associated angiogenesis occurs via concomitant downregulation of vascular endothelial growth factor and matrix metalloproteinase 2. This study provides compelling evidence that FBLN2S has an important tumor-suppressive and anti-angiogenic role in NPC.

Journal of Cellular Biochemistry, 2009

Epidermal growth factor receptor (EGFR), a receptor often expressed in nasopharyngeal carcinoma (... more Epidermal growth factor receptor (EGFR), a receptor often expressed in nasopharyngeal carcinoma (NPC) cells, is one of the recently identified molecular targets in cancer treatment. In the present study, the effects of combined treatment of Zn-BC-AM PDT with an EGFR inhibitor AG1478 were investigated. Well-differentiated NPC HK-1 cells were subjected to PDT with 1 mM of Zn-BC-AM and were irradiated at a light dose of 1 J/cm 2 in the presence or absence of EGFR inhibitor AG1478. Specific protein kinase inhibitors of downstream EGFR targets were also used in the investigation. EGFR, Akt, and ERK were found constitutively activated in HK-1 cells and the activities could be inhibited by the EGFR inhibitor AG1478. A sub-lethal concentration of AG1478 was found to further enhance the irreversible cell damage induced by Zn-BC-AM PDT in HK-1 cells. Pre-incubation of the cells with specific inhibitors of EGFR (AG1478), PI3k/Akt (LY294002), or MEK/ERK (PD98059) before light irradiation were found to enhance Zn-BC-AM PDT-induced formation of apoptotic cells. The efficacy of Zn-BC-AM PDT can be increased through the inhibition of EGFR/PI3K/Akt and EGFR/MEK/ERK signaling pathways in NPC cells. Combination therapy with Zn-BC-AM PDT and EGFR inhibitors may further be developed for the treatment of advanced NPC.

Cell Biochemistry and Function, 2010

Photodynamic therapy (PDT) with a recently developed photosensitizer Zn-BC-AM was found to effect... more Photodynamic therapy (PDT) with a recently developed photosensitizer Zn-BC-AM was found to effectively induce apoptosis in a welldifferentiated nasopharyngeal carcinoma (NPC) HK-1 cell line. Sustained activation of p38 mitogen-activated protein kinase (MAPK) and cjun N-terminal kinase (JNK) as well as a transient increase in activation of extracellular-regulated kinase (ERK) were observed immediately after Zn-BC-AM PDT. A commonly used p38 MAPK/JNK pharmacological inhibitor PD169316 was found to reduce PDT-induced apoptosis of HK-1 cells. PD169316 also prevented the loss of Bcl-2 and Bcl-xL in PDT-treated HK-1 cells. However, inhibition of JNK with SP600125 had no effect on Zn-BC-AM PDT-induced apoptosis while inhibition of ERK with PD98059 or p38 MAPK with SB203580 significantly increased Zn-BC-AM PDT-induced apoptosis. Further study showed that knockdown of the p38b isoform with siRNA also increased Zn-BC-AM PDT-induced apoptosis, indicating that the anti-apoptotic effect of PD169316 in PDT-treated HK-1 cells was probably independent of p38 MAPK or JNK activation. Taken together, the results suggest that inhibition of p38b and ERK may enhance the therapeutic efficacy of Zn-BC-AM PDT on NPC cells. It should be noted that data only based on the use of PD169316 should be interpreted in caution.

Biosensors and Bioelectronics, 1999

A microbial biosensor based on the yeast Arxula adeninivorans LS3 has been developed for measurem... more A microbial biosensor based on the yeast Arxula adeninivorans LS3 has been developed for measurement of biodegradable substances. Arxula is immobilized in the hydrogel poly(carbamoyl) sulfonate (PCS). The immobilized yeast membrane is placed in front of an oxygen electrode with Ϫ 600 mV versus Ag/AgCl. Arxula is salt tolerant; it can give a stable signal up to 2.5 M NaCl in sample (120 mM in measuring cell). The sensor's measurements are highly correlated to BOD 5 measurements. It has a very high stability which can last for 40 days without any decrease in signal. The linear range of the sensor is up to a corresponding BOD value of 550 mg/l.

The key genes involved in the development of esophageal squamous cell carcinoma (ESCC) remain to ... more The key genes involved in the development of esophageal squamous cell carcinoma (ESCC) remain to be elucidated. Previous studies indicate extensive genomic alterations occur on chromosome 9 in ESCC. Using a monochromosome transfer approach, this study provides functional evidence and narrows down the critical region (CR) responsible for chromosome 9 tumor suppressing activity to a 2.4 Mb region mapping to 9q33–q34 between markers D9S1798 and D9S61. Interestingly, a high prevalence of allelic loss in this CR is also observed in primary ESCC tumors by microsatellite typing. Allelic loss is found in 30/34 (88%) tumors and the loss of heterozygosity (LOH) frequency ranges from 67 to 86%. Absent to low expression of a 9q32 candidate tumor suppressor gene (TSG), DEC1 (deleted in esophageal cancer 1), is detected in four Asian ESCC cell lines. Stably expressing DEC1 transfectants provide functional evidence for inhibition of tumor growth in nude mice and DEC1 expression is decreased in tum...

In many cancers, including nasopharyngeal carcinoma (NPC), extensive and multiple regions of alle... more In many cancers, including nasopharyngeal carcinoma (NPC), extensive and multiple regions of allelic loss occur on chromosome 14. However, to date no functionally conclusive tumor suppressor genes have yet been identified on this chromosome. Through use of the monochromosome transfer technique, this study provides functional evidence for the importance of two discrete regions of chromosome 14. A newly established A9 mouse donor cell line containing an intact copy of chromosome 14 was used for transfer of this intact chromosome into the NPC HONE1 cell line. Twelve independently established microcell hybrids demonstrated uniform loss of specific chromosome 14 loci from both endogenous and exogenous alleles. By microsatellite typing and fluorescence in situ hybridization with BAC probes, the two critical regions were localized to 14q11.2–13.1 and 14q32.1. Selective elimination of these regions during hybrid selection was strongly associated with both hybrid survival and tumor growth in...

Orthotopic xenograft model recapitulates the faithful organ-specific microenvironment and facilit... more Orthotopic xenograft model recapitulates the faithful organ-specific microenvironment and facilitates analyses involving tumor-stromal interactions that are crucial for developing new-generation cancer therapy. Herein, we describe the detailed rationales and protocols of a versatile orthotopic xenograft model for esophageal squamous cell carcinoma.

Advanced Science

Germline polymorphisms are linked with differential survival outcomes in cancers but are not well... more Germline polymorphisms are linked with differential survival outcomes in cancers but are not well studied in nasopharyngeal carcinoma (NPC). Here, a two-phase association study is conducted to discover germline polymorphisms that are associated with the prognosis of NPC. The discovery phase includes two consecutive hospital cohorts of patients with NPC from Southern China. Exome-wide genotypes at 246 173 single nucleotide polymorphisms (SNPs) are determined, followed by survival analysis for each SNP under Cox proportional hazard regression model. Candidate SNP is replicated in another two independent cohorts from Southern China and Singapore. Meta-analysis of all samples (n = 5553) confirms that the presence of rs1131636-T, located in the 3′-UTR of RPA1, confers an inferior overall survival (HR = 1.33, 95% CI = 1.20-1.47, P = 6.31 × 10 −8). Bioinformatics and biological assays show that rs1131636 has regulatory effects on upstream RPA1. Functional studies further demonstrate that RPA1 promotes the growth, invasion, migration, and radioresistance of NPC cells. Additionally, miR-1253 is identified as a suppressor for RPA1 expression, likely through regulation of its binding affinity to rs1131636 locus. Collectively, these findings provide a promising biomarker aiding in stratifying patients with poor survival, as well as a potential drug target for NPC.

Molecular and Cellular Biology / Genetics

International journal of cancer, Jan 4, 2018

Nasopharyngeal carcinoma is an Epstein-Barr Virus (EBV) associated malignancy which is highly pre... more Nasopharyngeal carcinoma is an Epstein-Barr Virus (EBV) associated malignancy which is highly prevalent in Southeast Asia. EBV-related antibodies have been widely used as screening markers for early nasopharyngeal carcinoma (NPC) detection. However, due to low positive predictive rate, it is essential to develop new biomarkers to facilitate NPC early diagnosis or triage EBV serological high-risk individuals to improve the chance of NPC early detection. BART microRNAs, which are encoded by BamHI region of EBV, were reported to be abundant in NPC and have potential value in early diagnosis of NPC. Here, we quantified the circulating level of 17 BART microRNAs in discovery stage based on previous microarray and sequencing data and, in particular, BART 2-5p, the sole candidate whose AUC was higher than 0.8, has been chosen for further study. In validation stage, the sensitivity, specificity and AUC of BART 2-5p was 93.9%, 89.8%, 0.972(95%CI: 0.954-0.989) respectively in cohort 1 constit...