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1.  Prognostic Significance of Promoter DNA Hypermethylation of cysteine dioxygenase 1 (CDO1) Gene in Primary Breast Cancer 
PLoS ONE  2016;11(1):e0144862.
Using pharmacological unmasking microarray, we identified promoter DNA methylation of cysteine dioxygenase 1 (CDO1) gene in human cancer. In this study, we assessed the clinicopathological significance of CDO1 methylation in primary breast cancer (BC) with no prior chemotherapy. The CDO1 DNA methylation was quantified by TaqMan methylation specific PCR (Q-MSP) in 7 BC cell lines and 172 primary BC patients with no prior chemotherapy. Promoter DNA of the CDO1 gene was hypermethylated in 6 BC cell lines except SK-BR3, and CDO1 gene expression was all silenced at mRNA level in the 7 BC cell lines. Quantification of CDO1 methylation was developed using Q-MSP, and assessed in primary BC. Among the clinicopathologic factors, CDO1 methylation level was not statistically significantly associated with any prognostic factors. The log-rank plot analysis elucidated that the higher methylation the tumors harbored, the poorer prognosis the patients exhibited. Using the median value of 58.0 as a cut-off one, disease specific survival in BC patients with CDO1 hypermethylation showed significantly poorer prognosis than those with hypomethylation (p = 0.004). Multivariate Cox proportional hazards model identified that CDO1 hypermethylation was prognostic factor as well as Ki-67 and hormone receptor status. The most intriguingly, CDO1 hypermethylation was of robust prognostic relevance in triple negative BC (p = 0.007). Promoter DNA methylation of CDO1 gene was robust prognostic indicator in primary BC patients with no prior chemotherapy. Prognostic relevance of the CDO1 promoter DNA methylation is worthy of being paid attention in triple negative BC cancer.
PMCID: PMC4718689  PMID: 26785325
2.  Silencing of high-mobility group box 2 (HMGB2) modulates cisplatin and 5-fluorouracil sensitivity in head and neck squamous cell carcinoma 
Proteomics  2015;15(0):383-393.
Dysregulation of protein expression is associated with most diseases including cancer. Mass spectrometry-based proteomic analysis is widely employed as a tool to study protein dysregulation in cancers. Proteins which are differentially expressed in head and neck squamous cell carcinoma (HNSCC) cell lines compared to the normal oral cell line could serve as biomarkers for patient stratification. To understand the proteomic complexity in HNSCC, we carried out iTRAQ-based mass spectrometry analysis on a panel of HNSCC cell lines in addition to a normal oral keratinocyte cell line. LC-MS/MS analysis of total proteome of the HNSCC cell lines led to the identification of 3,263 proteins, of which 185 proteins were overexpressed and 190 proteins were downregulated more than 2-fold in at least two of the three HNSCC cell lines studied. Amongst the overexpressed proteins, 23 proteins were related to DNA replication and repair. These included high mobility group box 2 (HMGB2) protein, which was overexpressed in all three HNSCC lines studied. Overexpression of HMGB2 has been reported in various cancers, yet its role in HNSCC remains unclear. Immunohistochemical labeling of HMGB2 in a panel of HNSCC tumors using tissue microarrays revealed overexpression in 77% (54 of 70) of tumors. The HMGB proteins are known to bind to DNA structure resulting from cisplatin-DNA adducts and affect the chemosensitivity of cells. We observed that siRNA-mediated silencing of HMGB2 increased the sensitivity of the HNSCC cell lines to cisplatin and 5-FU. We hypothesize that targeting HMGB2 could enhance the efficacy of existing chemotherapeutic regimens for treatment of HNSCC.
PMCID: PMC4528963  PMID: 25327479
antimetabolite; biomarker; drug resistance; in vitro labeling
3.  Words Matter: Distinguishing “Personalized Medicine” and “Biologically Personalized Therapeutics” 
“Personalized medicine” has become a generic term referring to techniques that evaluate either the host or the disease to enhance the likelihood of beneficial patient outcomes from treatment interventions. There is, however, much more to personalization of care than just identifying the biotherapeutic strategy with the highest likelihood of benefit. In its new meaning, “personalized medicine” could overshadow the individually tailored, whole-person care that is at the bedrock of what people need and want when they are ill. Since names and definitional terms set the scope of the discourse, they have the power to define what personalized medicine includes or does not include, thus influencing the scope of the professional purview regarding the delivery of personalized care. Taxonomic accuracy is important in understanding the differences between therapeutic interventions that are distinguishable in their aims, indications, scope, benefits, and risks. In order to restore the due emphasis to the patient and his or her needs, we assert that it is necessary, albeit belated, to deconflate the contemporary term “personalized medicine” by taxonomizing this therapeutic strategy more accurately as “biologically personalized therapeutics” (BPT). The scope of truly personalized medicine and its relationship to biologically personalized therapeutics is described, emphasizing that the best of care must give due recognition and emphasis to both BPT and truly personalized medicine.
PMCID: PMC4568994  PMID: 25293984
4.  A Pilot Clinical Study of Treatment Guided by Personalized Tumorgrafts in Patients with Advanced Cancer 
Molecular cancer therapeutics  2011;10(8):1311-1316.
Patients with many advanced solid cancers have very poor prognosis, and improvements in life expectancy are measured only in months. We have recently reported the remarkable clinical outcome of a patient with advanced, gemcitabine-resistant, pancreatic cancer who was later treated with DNA-damaging agents, on the basis of the observation of significant activity of this class of drugs against a personalized tumorgraft generated from the patient’s surgically resected tumor. Here, we extend the approach to patients with other advanced cancers. Tumors resected from 14 patients with refractory advanced cancers were propagated in immunodeficient mice and treated with 63 drugs in 232 treatment regimens. An effective treatment regimen in the xenograft model was identified for 12 patients. One patient died before receiving treatment, and the remaining 11 patients received 17 prospectively guided treatments. Fifteen of these treatments resulted in durable partial remissions. In 2 subjects, no effective treatments were found. Overall, there was a remarkable correlation between drug activity in the model and clinical outcome, both in terms of resistance and sensitivity. The data support the use of the personalized tumorgraft model as a powerful investigational platform for therapeutic decision making and to efficiently guide cancer treatment in the clinic.
PMCID: PMC4629061  PMID: 21673092
5.  Elevated AKAP12 in Paclitaxel-Resistant Serous Ovarian Cancer Cells is Prognostic and Predictive of Poor Survival in Patients 
Journal of proteome research  2015;14(4):1900-1910.
A majority of high-grade (HG) serous ovarian cancer (SOC) patients develop resistant disease despite high initial response rates to platinum/paclitaxel-based chemotherapy. We identified shed/secreted proteins in preclinical models of paclitaxel-resistant human HGSOC models and correlated these candidate proteins with patient outcomes using public data from HGSOC patients. Proteomic analyses of a HGSOC cell line secretome was compared to those from a syngeneic paclitaxel-resistant variant and from a line established from an intrinsically chemorefractory HGSOC patient Associations between the identified candidate proteins and patient outcome were assessed in a discovery cohort of 545 patients and two validation cohorts totaling 795 independent SOC patients. Among the 81 differentially abundant proteins identified (q < 0.05) from paclitaxel-sensitive vs -resistant HGSOC cell secretomes, AKAP12 was verified to be elevated in all models of paclitaxel-resistant HGSOC. Furthermore, elevated AKAP12 transcript expression was associated with worse progression-free and overall survival. Associations with outcome were observed in three independent cohorts and remained significant after adjusted multivariate modeling. We further provide evidence to support that differential gene methyktion status is associated with elevated expression of AKAP12 in taxol-resistant ovarian cancer cells and ovarian cancer patient subsets. Elevated expression and shedding/secretion of AKAP12 is characteristic of paclitaxel-resistant HGSOC cells, and elevated AKAP12 transcript expression is a poor prognostic and predictive marker for progression-free and overall survival in SOC patients.
PMCID: PMC4612617  PMID: 25748058
Ovarian cancer; proteomics; secretome; AKAP12; paclitaxel resistance
6.  The Oral Cavity as a Molecular Mirror of Lung Carcinogenesis 
PMCID: PMC4604561  PMID: 19138931
7.  Targeted sequencing reveals clonal genetic changes in the progression of early lung neoplasms and paired circulating DNA 
Nature Communications  2015;6:8258.
Lungs resected for adenocarcinomas often harbour minute discrete foci of cytologically atypical pneumocyte proliferations designated as atypical adenomatous hyperplasia (AAH). Evidence suggests that AAH represents an initial step in the progression to adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA) and fully invasive adenocarcinoma. Despite efforts to identify predictive markers of malignant transformation, alterations driving this progression are poorly understood. Here we perform targeted next-generation sequencing on multifocal AAHs and different zones of histologic progression within AISs and MIAs. Multiregion sequencing demonstrated different genetic drivers within the same tumour and reveal that clonal expansion is an early event of tumorigenesis. We find that KRAS, TP53 and EGFR mutations are indicators of malignant transition. Utilizing droplet digital PCR, we find alterations associated with early neoplasms in paired circulating DNA. This study provides insight into the heterogeneity of clonal events in the progression of early lung neoplasia and demonstrates that these events can be detected even before neoplasms have invaded and acquired malignant potential.
Atypical adenomatous hyperplasia is thought to be a precursor lesion for lung adenocarcinoma. Here, using targeted deep sequencing, the authors demonstrate that hyperplastic lesions contain somatic mutations associated with malignant disease and that these can be detected in circulating tumour cells.
PMCID: PMC4595648  PMID: 26374070
8.  Detection of somatic mutations and HPV in the saliva and plasma of patients with head and neck squamous cell carcinomas 
Science translational medicine  2015;7(293):293ra104.
To explore the potential of tumor-specific DNA as a biomarker for head and neck squamous cell carcinomas (HNSCC), we queried DNA from saliva or plasma of 93 HNSCC patients. We searched for somatic mutations or human papillomavirus genes, collectively referred to as tumor DNA. When both plasma and saliva were tested, tumor DNA was detected in 96% of 47 patients. The fractions of patients with detectable tumor DNA in early- and late-stage disease were 100% (n = 10) and 95% (n = 37), respectively. When segregated by site, tumor DNA was detected in 100% (n = 15), 91% (n = 22), 100% (n = 7), and 100% (n = 3) of patients with tumors of the oral cavity, oropharynx, larynx, and hypopharynx, respectively. In saliva, tumor DNA was found in 100% of patients with oral cavity cancers and in 47 to 70% of patients with cancers of the other sites. In plasma, tumor DNA was found in 80% of patients with oral cavity cancers, and in 86 to 100% of patients with cancers of the other sites. Thus, saliva is preferentially enriched for tumor DNA from the oral cavity, whereas plasma is preferentially enriched for tumor DNA from the other sites. Tumor DNA in saliva was found postsurgically in three patients before clinical diagnosis of recurrence, but in none of the five patients without recurrence. Tumor DNA in the saliva and plasma appears to be a potentially valuable biomarker for detection of HNSCC.
PMCID: PMC4587492  PMID: 26109104
9.  An integrated genome-wide approach to discover deregulated microRNAs in non-small cell lung cancer: Clinical significance of miR-23b-3p deregulation 
Scientific Reports  2015;5:13236.
In spite of significant technical advances, genesis and progression of non-small cell lung cancer (NSCLC) remain poorly understood. We undertook an integrated genetic approach to discover novel microRNAs that were deregulated in NSCLCs. A total 119 primary NSCLCs with matched normal were analyzed for genome-wide copy number changes. We also tested a subset of matched samples by microRNA expression array, and integrated them to identify microRNAs positioned in allelic imbalance area. Our findings support that most of the identified deregulated microRNAs (miR-21, miR-23b, miR-31, miR-126, miR-150, and miR-205) were positioned in allelic imbalance areas. Among microRNAs tested in independent 114 NSCLCs, overexpression of miR-23b was revealed to be a significantly poor prognostic factor of recurrence free survival (HR = 2.40, P = 0.005, 95%CI: 1.32–4.29) and overall survival (HR = 2.35, P = 0.005, 95%CI: 1.30–4.19) in multivariable analysis. In addition, overexpression of miR-23b in H1838 cell line significantly increased cell proliferation, while inhibition of miR-23b in H1437 and H1944 cell lines significantly decreased cell doubling time. In summary, integration of genomic analysis and microRNA expression profiling could identify novel cancer-related microRNAs, and miR-23b could be a potential prognostic marker for early stage NSCLCs. Further biological studies of miR-23b are warranted for the potential development of targeted therapy.
PMCID: PMC4551983  PMID: 26314549
10.  The TGFβ-miR200-Mig6 pathway orchestrates the EMT-associated kinase switch that induces resistance to EGFR inhibitors 
Cancer research  2014;74(14):3995-4005.
While specific mutations in the tyrosine kinase domain of epidermal growth factor receptor (EGFR) identify tumors that are responsive to EGFR tyrosine kinase inhibitors (TKIs), these genetic alterations are present in only a minority of patients. Patients with tumors expressing wild-type (wt) EGFR lack reliable predictive markers of their clinical response to EGFR TKIs. Although epithelial-mesenchymal transition (EMT) has been inversely correlated with the response of cancers to EGFR-targeted therapy, the precise molecular mechanisms underlying this association have not been defined and no specific EMT-associated biomarker of clinical benefit has been identified. Here we show that during transforming growth factor-β (TGFβ)-mediated EMT, inhibition of the microRNAs 200 (miR200) family results in upregulated expression of mitogen-inducible gene 6 (Mig6), a negative regulator of EGFR. The Mig6-mediated reduction of EGFR occurs concomitantly with a TGFβ-induced EMT-associated kinase switch of tumor cells to an AKT-activated EGFR-independent state. In a panel of 25 cancer cell lines of different tissue origins, we find that the ratio of the expression levels of Mig6 and miR200c is highly correlated with EMT and resistance to erlotinib. Analyses of primary tumor xenografts of patient-derived lung and pancreatic cancers carrying wild type EGFR showed that the tumor Mig6(mRNA)/miR200 ratio was inversely correlated with response to erlotinib in vivo. Our data demonstrate that the TGFβ-miR200-Mig6 network orchestrates the EMT-associated kinase switch that induces resistance to EGFR inhibitors, and identify a low ratio of Mig6 to miR200 as a promising predictive biomarker of the response of tumors to EGFR TKIs.
PMCID: PMC4122100  PMID: 24830724
11.  Key tumor suppressor genes inactivated by “greater promoter” methylation and somatic mutations in head and neck cancer 
Epigenetics  2014;9(7):1031-1046.
Tumor suppressor genes (TSGs) are commonly inactivated by somatic mutation and/or promoter methylation; yet, recent high-throughput genomic studies have not identified key TSGs inactivated by both mechanisms. We pursued an integrated molecular analysis based on methylation binding domain sequencing (MBD-seq), 450K Methylation arrays, whole exome sequencing, and whole genome gene expression arrays in primary head and neck squamous cell carcinoma (HNSCC) tumors and matched uvulopalatopharyngoplasty tissue samples (UPPPs). We uncovered 186 downregulated genes harboring cancer specific promoter methylation including PAX1 and PAX5 and we identified 10 key tumor suppressor genes (GABRB3, HOXC12, PARP15, SLCO4C1, CDKN2A, PAX1, PIK3AP1, HOXC6, PLCB1, and ZIC4) inactivated by both promoter methylation and/or somatic mutation. Among the novel tumor suppressor genes discovered with dual mechanisms of inactivation, we found a high frequency of genomic and epigenomic alterations in the PAX gene family of transcription factors, which selectively impact canonical NOTCH and TP53 pathways to determine cell fate, cell survival, and genome maintenance. Our results highlight the importance of assessing TSGs at the genomic and epigenomic level to identify key pathways in HNSCC, deregulated by simultaneous promoter methylation and somatic mutations.
PMCID: PMC4143405  PMID: 24786473
Head and Neck Squamous Cell Carcinoma; Tumor Suppressor Genes; DNA methylation; somatic mutations; integration analysis
CpG island hypermethylation is emerging as one of the main mechanisms for inactivation of cancer related genes in breast tumorigenesis. We examined the changes in methylation patterns during ductal breast cancer progression from atypical ductal hyperplasia to in situ and invasive carcinoma. Paired samples of synchronous pre invasive lesions (Atypical Ductal Hyperplasia and/or Ductal Carcinoma in situ) and invasive ductal breast carcinoma from 31 patients, together with isolated lesions from additional 24 patients were studied. Overall, 95 pathological samples and 20 normal breast tissues were analyzed by Quantitative Methylation Specific PCR (QMSP) on a panel of 9 gene promoters (ESR1, APC, CDH1, CTNNB1, GSTPI, THBS1, MGMT, TMS1 and TIMP3). APC, CDH1, and CTNNB1 promoter regions showed an increase in frequency of methylation and increased methylation levels in pathological samples when compared with normal breast tissues. The analysis of the syncronous paired breast lesions demonstrated also an increase in methylation frequency and level for APC, CDH1, and CTNNB1 genes during progression. By establishing a cutoff value, we were able to distinguish among -invasive and invasive lesions. Synchronous methylation of APC, CDH1, and CTNNB1 was associated only with invasive lesions, whereas simultaneous methylation of APC and CDH1 or APC and CTNNB1 were more frequent in ductal carcinoma in situ and invasive carcinoma. Our data point to direct involvement of APC, CDH1, and CTNNB1 CpG island promoter methylation in the early stages of breast cancer progression, and suggest that these molecular alterations might be involved in the transition to an invasive phenotype.
PMCID: PMC4441328  PMID: 19789364
Breast Cancer; DNA methylation/epigenetics; APC; β-catenin; E-cadherin
13.  GSTP1 Promoter Methylation is Associated with Recurrence in Early Stage Prostate Cancer 
The Journal of urology  2014;192(5):1542-1548.
Recurrent prostate cancer remains a major problem. Staging, grading and prostate specific antigen level at surgery are helpful but still imperfect predictors of recurrence. For this reason there is an imperative need for additional biomarkers that add to the prediction of currently used prognostic factors.
Materials and Methods
We evaluated the extent of promoter methylation of genes previously reported as aberrantly methylated in prostate cancer (AIM1, APC, CCND2, GPX3, GSTP1, MCAM, RARβ2, SSBP2 and TIMP3) by quantitative fluorogenic methylation-specific polymerase chain reaction. We used cancer tissue from a nested case-control study of 452 patients surgically treated for prostate cancer. Recurrence cases and controls were compared and the association between methylation extent and recurrence risk was estimated by logistic regression adjusting for patient age at prostatectomy, prostatectomy year, stage, grade, surgical margins and preprostatectomy prostate specific antigen. All statistical tests were 2-sided with p ≤0.05 considered statistically significant.
The extent of GSTP1 methylation was higher in patients with recurrence than in controls (p = 0.01), especially patients with early disease, ie organ confined or limited extraprostatic extension (p = 0.001). After multivariate adjustment GSTP1 promoter methylation at or above the median was associated with an increased risk of recurrence, including in men with early disease (each p = 0.05).
Greater GSTP1 promoter methylation in cancer tissue was independently associated with the risk of recurrence in patients with early prostate cancer. This suggests that GSTP1 promoter methylation may be a potential tissue based recurrence marker.
PMCID: PMC4390043  PMID: 24769028
prostatic neoplasms; neoplasm recurrence; local; glutathione S-transferase pi; methylation; biological markers
14.  Epigenetic silencing of S100A2 in bladder and head and neck cancers 
Oncoscience  2015;2(4):410-418.
S100A2, a member of the S100 protein family, is known to be downregulated in a number of human cancers, leading to its designation as a potential tumor suppressor gene. Here, we investigated the expression and methylation status of S100A2 in head&neck and bladder cancer. Reduced mRNA and protein expression was observed in 8 head&neck and bladder cancer cell lines. To explore the mechanism responsible for the downregulation of S100A2, we treated six cell lines with 5-aza-2′-deoxycytidine. We found S100A2 is silenced in association with aberrant promoter-region methylation and its expression is restored with 5-aza-2′-deoxycytidine treatment. Of 31 primary head&neck cancer cases and 31 bladder cancer cases, promoter methylation was detected in 90% and 80% of cases, respectively. Interestingly, only 1/9 of normal head&neck tissues and 2/6 of normal bladder tissues showed promoter methylation. S100A2 promoter methylation can be detected in urine and is more frequent in bladder cancer patients than in healthy subjects (96% vs 48% respectively). Moreover, increased methylation of S100A2 is linked to the progression of the tumor in bladder cancer (p<0.01). Together, this data shows that methylation-associated inactivation of S100A2 is frequent and may be an important event in the tumorigenesis of head&neck and bladder cancer.
PMCID: PMC4468326  PMID: 26097874
S100A2; methylation; head and neck cancer; bladder cancer; epigenetics
15.  Global and gene-specific DNA methylation pattern discriminates cholecystitis from gallbladder cancer patients in Chile 
Future oncology (London, England)  2014;11(2):233-249.
The aim of the study was to evaluate the use of global and gene-specific DNA methylation changes as potential biomarkers for gallbladder cancer (GBC) in a cohort from Chile.
Material & methods
DNA methylation was analyzed through an ELISA-based technique and quantitative methylation-specific PCR.
Global DNA Methylation Index (p = 0.02) and promoter methylation of SSBP2 (p = 0.01) and ESR1 (p = 0.05) were significantly different in GBC when compared with cholecystitis. Receiver curve operator analysis revealed promoter methylation of APC, CDKN2A, ESR1, PGP9.5 and SSBP2, together with the Global DNA Methylation Index, had 71% sensitivity, 95% specificity, a 0.97 area under the curve and a positive predictive value of 90%.
Global and gene-specific DNA methylation may be useful biomarkers for GBC clinical assessment.
PMCID: PMC4332836  PMID: 25066711
gallbladder cancer; global and gene-specific DNA methylation; molecular biomarkers panel; tumor suppressor genes
16.  Activation of the NOTCH pathway in Head and Neck Cancer 
Cancer research  2013;74(4):1091-1104.
NOTCH1 mutations have been reported to occur in 10 to 15% of head and neck squamous cell carcinomas (HNSCC). To determine the significance of these mutations, we embarked upon a comprehensive study of NOTCH signaling in a cohort of 44 HNSCC tumors and 25 normal mucosal samples through a set of expression, copy number, methylation and mutation analyses. Copy number increases were identified in NOTCH pathway genes including the NOTCH ligand JAG1. Gene set analysis defined a differential expression of the NOTCH signaling pathway in HNSCC relative to normal tissues. Analysis of individual pathway-related genes revealed overexpression of ligands JAG1 and JAG2 and receptor NOTCH3. In 32% of the HNSCC examined, activation of the downstream NOTCH effectors HES1/HEY1 was documented. Notably, exomic sequencing identified 5 novel inactivating NOTCH1 mutations in 4/37 of the tumors analyzed, with none of these tumors exhibiting HES1/HEY1 overexpression. Our results revealed a bimodal pattern of NOTCH pathway alterations in HNSCC, with a smaller subset exhibiting inactivating NOTCH1 receptors mutations but a larger subset exhibiting other NOTCH1 pathway alterations, including increases in expression or gene copy number of the receptor or ligands as well as downstream pathway activation. Our results imply that therapies that target the NOTCH pathway may be more widely suitable for HNSCC treatment than appreciated currently.
PMCID: PMC3944644  PMID: 24351288
17.  Clusterin is a Gene Specific Target of MicroRNA-21 in Head and Neck Squamous Cell Carcinoma 
MicroRNA-21 (miRNA-21) has proto-oncogenic properties, though no miRNA-21 specific targets have been found in head and neck squamous cell carcinoma (HNSCC). Further study of miRNA-21 and its specific targets is essential to understanding HNSCC biology.
Experimental Design:
miRNA expression profiles of 10 HNSCC and 10 normal mucosa samples were investigated using a custom miRNA microarray. 13 HNSCC and 5 normal mucosa primary tissue specimens underwent mRNA expression microarray analysis. To identify miRNA-21 downstream targets, oral keratinocyte cells were subjected to microarray analysis after miRNA-21 transient transfection. miRNA and mRNA expression were validated by RT-qPCR in a separate cohort of 16 HNSCC and 15 normal mucosal samples. Microarray and bioinformatics analyses were integrated to identify potential gene targets. In vitro assays looked at the function and interaction of miRNA-21 and its specific gene targets.
miRNA-21 was upregulated in HNSCC and stimulated cell growth. Integrated analyses identified Clusterin (CLU) as a potential miRNA-21 gene target. CLU was downregulated after forced expression of miRNA-21 in normal and HNSCC cell lines. The activity of a luciferase construct containing the 3’UTR of CLU was repressed by the ectopic expression of miRNA-21. CLU was also downregulated in primary HNSCC and correlated with miRNA-21 over-expression. CLU variant 1 (CLU-1) was the predominant splice variant in HNSCC, and showed growth suppression function that was reversed by miRNA-21 over-expression.
CLU is a specific, functional target of oncogenic miRNA-21 in HNSCC. CLU-1 isoform is the predominant growth suppressive variant targeted by miRNA-21.
PMCID: PMC3970211  PMID: 24327270
Clusterin; microRNA-21; gene target; tumor-suppressor gene; head and neck cancer
18.  Integrated Next-Generation Sequencing and Avatar Mouse Models for Personalized Cancer Treatment 
Current technology permits an unbiased massive analysis of somatic genetic alterations from tumor DNA as well as the generation of individualized mouse xenografts (Avatar models). This work aimed to evaluate our experience integrating these two strategies to personalize the treatment of patients with cancer.
We performed whole-exome sequencing analysis of 25 patients with advanced solid tumors to identify putatively actionable tumor-specific genomic alterations. Avatar models were used as an in vivo platform to test proposed treatment strategies.
Successful exome sequencing analyses have been obtained for 23 patients. Tumor-specific mutations and copy-number variations were identified. All samples profiled contained relevant genomic alterations. Tumor was implanted to create an Avatar model from 14 patients and 10 succeeded. Occasionally, actionable alterations such as mutations in NF1, PI3KA, and DDR2 failed to provide any benefit when a targeted drug was tested in the Avatar and, accordingly, treatment of the patients with these drugs was not effective. To date, 13 patients have received a personalized treatment and 6 achieved durable partial remissions. Prior testing of candidate treatments in Avatar models correlated with clinical response and helped to select empirical treatments in some patients with no actionable mutations.
The use of full genomic analysis for cancer care is encouraging but presents important challenges that will need to be solved for broad clinical application. Avatar models are a promising investigational platform for therapeutic decision making. While limitations still exist, this strategy should be further tested.
PMCID: PMC4322867  PMID: 24634382
19.  Detection of Methylated CDO1 in Plasma of Colorectal Cancer; A PCR Study 
PLoS ONE  2014;9(12):e113546.
Cysteine biology is important for the chemosensitivity of cancer cells. Our research has focused on the epigenetic silencing of cysteine dioxygenase type 1 (CDO1) in colorectal cancer (CRC). In this study, we describe detection of CDO1 methylation in the plasma of CRC patients using methylation specific PCR (Q-MSP) and extensive analysis of the PCR reaction.
DNA was extracted from plasma, and analysed for methylation of the CDO1 gene using Q-MSP. The detection rate of CDO1 gene methylation was calculated and compared with that of diluted DNA extracted from “positive control” DLD1 cells. CDO1 gene methylation in the plasma of 40 CRC patients that were clinicopathologically analysed was then determined.
(1) The cloned sequence analysis detected 93.3% methylation of the promoter CpG islands of the CDO1 gene of positive control DLD1 cells and 4.7% methylation of the negative control HepG2 CDO1 gene. (2) DLD1 CDO1 DNA could not be detected in this assay if the extracted DNA was diluted ∼1000 fold. The more DNA that was used for the PCR reaction, the more effectively it was amplified in Q-MSP. (3) By increasing the amount of DNA used, methylated CDO1 could be clearly detected in the plasma of 8 (20%) of the CRC patients. However, the percentage of CRC patients detected by methylated CDO1 in plasma was lower than that detected by CEA (35.9%) or CA19-9 (23.1%) in preoperative serum. Combination of CEA/CA19-9 plus plasma methylated CDO1 could increase the rate of detection of curable CRC patients (39.3%) as compared to CEA/CA19-9 (25%).
We have described detection of CDO1 methylation in the plasma of CRC patients. Although CDO1 methylation was not detected as frequently as conventional tumor markers, analysis of plasma CDO1 methylation in combination with CEA/CA19-9 levels increases the detection rate of curable CRC patients.
PMCID: PMC4254285  PMID: 25469504
20.  MDA-9/Syntenin regulates differentiation and angiogenesis programs in head and neck squamous cell carcinoma 
Oncoscience  2014;1(11):725-737.
Little is known about the molecular pathways regulating poor differentiation and invasion of head and neck squamous cell carcinoma (HNSCC). In the present study, we aimed to determine the role of MDA-9/Syntenin, a metastasis associated molecule in HNSCC tumorigenesis. Elevated MDA-9/Syntenin expression was evident in 67% (54/81) primary HNSCC tumors (p=0.001-0.002) and 69% (9/13) pre-neoplastic tissues (p=0.02-0.03). MDA-9/Syntenin overexpression was associated with the stage (p=0.001), grade (p=0.001) and lymph node metastasis (p=0.0001). Silencing of MDA-9/Syntenin in 3 poorly differentiated HNSCC cell lines induced squamous epithelial cell differentiation, disrupted angiogenesis and reduced tumor growth in vitro and in vivo. We confirmed SPRR1B and VEGFR1 as the key molecular targets of MDA-9/Syntenin on influencing HNSCC differentiation and angiogenesis respectively. MDA-9/Syntenin disrupted SPRR1B expression interacting through its PDZ1 domain and altered VEGFR1 expression in vitro and in vivo. VEGFR1 co-localized with MDA-9/Syntenin in HNSCC cell lines and primary tumor. Downregulation of growth regulatory molecules CyclinD1, CDK4, STAT3, PI3K and CTNNB1 was also evident in the MDA-9/Syntenin depleted cells, which was reversed following over-expression of MDA-9/Syntenin in immortalized oral epithelial cells. Our results suggest that early induction of MDA-9/Syntenin expression influences HNSCC progression and should be further evaluated for potential biomarker development.
PMCID: PMC4278274  PMID: 25593999
Head and neck suqamous cell carcinoma; MDA-9/Syntenin; differentiation; SPRR1B; VEGFR1
21.  Cold atmospheric plasma treatment selectively targets head and neck squamous cell carcinoma cells 
The treatment of locoregional recurrence (LRR) of head and neck squamous cell carcinoma (HNSCC) often requires a combination of surgery, radiation therapy and/or chemotherapy. Survival outcomes are poor and the treatment outcomes are morbid. Cold atmospheric plasma (CAP) is an ionized gas produced at room temperature under laboratory conditions. We have previously demonstrated that treatment with a CAP jet device selectively targets cancer cells using in vitro melanoma and in vivo bladder cancer models. In the present study, we wished to examine CAP selectivity in HNSCC in vitro models, and to explore its potential for use as a minimally invasive surgical approach that allows for specific cancer cell or tumor tissue ablation without affecting the surrounding healthy cells and tissues. Four HNSCC cell lines (JHU-022, JHU-028, JHU-029, SCC25) and 2 normal oral cavity epithelial cell lines (OKF6 and NOKsi) were subjected to cold plasma treatment for durations of 10, 30 and 45 sec, and a helium flow of 20 l/min−1 for 10 sec was used as a positive treatment control. We showed that cold plasma selectively diminished HNSCC cell viability in a dose-response manner, as evidenced by MTT assays; the viability of the OKF6 cells was not affected by the cold plasma. The results of colony formation assays also revealed a cell-specific response to cold plasma application. Western blot analysis did not provide evidence that the cleavage of PARP occurred following cold plasma treatment. In conclusion, our results suggest that cold plasma application selectively impairs HNSCC cell lines through non-apoptotic mechanisms, while having a minimal effect on normal oral cavity epithelial cell lines.
PMCID: PMC4152136  PMID: 25050490
head and neck squamous cell carcinoma; cold atmospheric plasma treatment; cold atmospheric plasma selectivity; head and neck squamous cell carcinoma adjuvant treatment; HPV-positive head and neck squamous cell carcinoma; HPV-negative head and neck squamous cell carcinoma
22.  PD-L1 expression in the Merkel cell carcinoma microenvironment: Association with inflammation, Merkel cell polyomavirus and overall survival 
Cancer immunology research  2013;1:10.1158/2326-6066.CIR-13-0034.
Merkel cell carcinoma (MCC) is a lethal, virus-associated cancer that lacks effective therapies for advanced disease. Agents blocking the PD-1/PD-L1 pathway have demonstrated objective, durable tumor regressions in patients with advanced solid malignancies and efficacy has been linked to PD-L1 expression in the tumor microenvironment. To investigate whether MCC might be a target for PD-1/PD-L1 blockade, we examined MCC PD-L1 expression, its association with tumor-infiltrating lymphocytes (TILs), Merkel cell polyomavirus (MCPyV), and overall survival. Sixty-seven MCC specimens from 49 patients were assessed with immunohistochemistry for PD-L1 expression by tumor cells and TILs, and immune infiltrates were characterized phenotypically. Tumor cell and TIL PD-L1 expression were observed in 49% and 55% of patients, respectively. In specimens with PD-L1(+) tumor cells, 97% (28/29) demonstrated a geographic association with immune infiltrates. Among specimens with moderate-severe TIL intensities, 100% (29/29) demonstrated PD-L1 expression by tumor cells. Significant associations were also observed between the presence of MCPyV DNA, a brisk inflammatory response, and tumor cell PD-L1 expression: MCPyV(−) tumor cells were uniformly PD-L1(−). Taken together, these findings suggest that a local tumor-specific and potentially MCPyV-specific immune response drives tumor PD-L1 expression, similar to previous observations in melanoma and head and neck squamous cell carcinomas. In multivariate analyses, PD-L1(−) MCCs were independently associated with worse overall survival (hazard ratio 3.12; 95% CI, 1.28-7.61; p=0.012). These findings suggest that an endogenous immune response promotes PD-L1 expression in the MCC microenvironment when MCPyV is present, and provide a rationale for investigating therapies blocking PD-1/PD-L1 for patients with MCC.
PMCID: PMC3885978  PMID: 24416729
Merkel cell carcinoma; PD-L1; B7-H1; immunotherapy; Merkel cell polyomavirus
23.  An epigenetic marker panel for recurrence risk prediction of low grade papillary urothelial cell carcinoma (LGPUCC) and its potential use for surveillance after transurethral resection using urine 
Oncotarget  2014;5(14):5218-5233.
By a candidate gene approach, we analyzed the promoter methylation (PM) of 8 genes (ARF, TIMP3, RAR-β2, NID2, CCNA1, AIM1, CALCA and CCND2) by quantitative methylation specific PCR (QMSP) in the DNA of 17 non-recurrent and 19 recurrent noninvasive low grade papillary urothelial cell carcinoma (LGPUCC) archival tissues. Among the genes tested, by establishing an empiric cutoff value, CCND2, CCNA1, NID2, and CALCA showed higher frequency of methylation in recurrent than in non-recurrent LGPUCC: CCND2 10/19 (53%) vs. 2/17 (12%) (p=0.014); CCNA1 11/19 (58%) vs. 4/17 (23.5%) (p=0.048); NID2 13/19 (68%) vs. 3/17 (18%) (p=0.003) and CALCA 10/19 (53%) vs. 4/17 (23.5%) (p=0.097), respectively. We further analyzed PM of CCND2, CCNA1, and CALCA in urine DNA from UCC patients including LGPUCC and controls. The frequency of CCND2, CCNA1, and CALCA was significantly higher (p<0.0001) in urine of UCC cases [38/148 (26%), 50/73 (68%) and 94/148 (63.5%) respectively] than controls [0/56 (0%), 10/60 (17%) and 16/56 (28.5%), respectively)]. Most importantly we found at least one of the 3 markers were methylated positive in 25 out of 30 (83%) cytology negative LGPUCC cases. We also explored the biological function of CCNA1 in UCC. Prospective confirmatory studies are needed to develop a reliable tool for prediction of recurrence using primary LGPUCC tissues and/or urine.
PMCID: PMC4170626  PMID: 24980822
LGPUCC; Recurrence; Epigenetics; Biomarkers; DNA methylation
24.  Differential promoter methylation of kinesin family member 1a in plasma is associated with breast cancer and DNA repair capacity 
Oncology Reports  2014;32(2):505-512.
Methylation alterations of CpG islands, CpG island shores and first exons are key events in the formation and progression of human cancer, and an increasing number of differentially methylated regions and genes have been identified in breast cancer. Recent studies of the breast cancer methylome using deep sequencing and microarray platforms are providing a novel insight on the different roles aberrant methylation plays in molecular subtypes of breast cancer. Accumulating evidence from a subset of studies suggests that promoter methylation of tumor-suppressor genes associated with breast cancer can be quantified in circulating DNA. However, there is a paucity of studies that examine the combined presence of genetic and epigenetic alterations associated with breast cancer using blood-based assays. Dysregulation of DNA repair capacity (DRC) is a genetic risk factor for breast cancer that has been measured in lymphocytes. We isolated plasma DNA from 340 participants in a breast cancer case control project to study promoter methylation levels of five genes previously shown to be associated with breast cancer in frozen tissue and in cell line DNA: MAL, KIF1A, FKBP4, VGF and OGDHL. Methylation of at least one gene was found in 49% of the cases compared to 20% of the controls. Three of the four genes had receiver characteristic operator curve values of ≥0.50: MAL (0.64), KIF1A (0.51) and OGDHL (0.53). KIF1A promoter methylation was associated with breast cancer and inversely associated with DRC. This is the first evidence of a significant association between genetic and epigenetic alterations in breast cancer using blood-based tests. The potential diagnostic utility of these biomarkers and their relevance for breast cancer risk prediction should be examined in larger cohorts.
PMCID: PMC4091885  PMID: 24927296
epigenetics; epigenetic biomarker panel; breast cancer; KIF1A; OGDHL; FKBP4; VGF; MAL promoter methylation; DNA repair capacity
25.  Clinical Correlates of Promoter Hypermethylation of Four Target Genes in Head and Neck Cancer: A Cooperative Group Correlative Study 
Promoter hypermethylation is a well documented mechanism for tumor-specific alteration of suppressor gene activity in human malignancy including Head and Neck Cancer (HNC). The abrogation of specific suppressor gene activity may influence tumor behavior and clinical outcome. In this study we examined methylation of DCC, KIF1A, EDNRB, and p16INK4a in a large cohort of HNC patients from ECOG 4393/RTOG 9614 to identify clinical correlates of methylation of these genes.
Methylation was assessed by quantitative methylation-specific polymerase chain reaction in DNA from tumor specimens and was considered as a continuous and a binary variable. Clinical data including demographics, stage, risk factor exposure, treatment, and outcome were collected by ECOG and RTOG. Methylation status was also correlated with mutation of TP53 (previously reported) and HPV status.
Methylation results were available for 368 cases, 353 of which also have p53 mutation status. At least one methylation event was present in all tumors. In multivariate analysis of the entire cohort, methylation of p16 was associated with decreased survival (HR=1.008, p=0.045). However, in tumors with disruptive TP53 mutation (poor prognostic group), the additional presence of methylation of p16 was protective (p=0.019 considering p16 methylation as a continuous variable).
Methylation of tumor-related genes contributes to the biological behavior of HNC and influences overall survival in conjunction with other known prognostic molecular events.
PMCID: PMC3642232  PMID: 23444219
head and neck cancer; methylation; survival

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