David Sidransky

Johns Hopkins University, Baltimore, Maryland, United States

Are you David Sidransky?

Claim your profile

Publications (355)2708 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The Notch pathway is frequently altered in HNSCCs, however the clinical significance of NOTCH1 dysregulation is poorly understood. This study was designed to characterize expression of the transcriptionally active NOTCH1 Intracellular Domain (NICD1) in HNSCCs and evaluate its association with NOTCH1 mutation status and clinical parameters. Immunohistochemistry for NICD1 was performed on 79 previously sequenced archival HNSCCs with known NOTCH1 mutation status. Three distinct immunohistochemical staining patterns were identified: positive/peripheral (47%), positive/non-peripheral (34%) and negative (19%). NICD1 expression was associated with NOTCH1 mutation status (p<0.001). Most NOTCH1-wild type tumors were peripheral (55%), while mutated NOTCH1 tumors were most commonly negative (47%). Non-peripheral tumors were more likely than peripheral tumors to have extracapsular spread (aOR 16.01, 95%CI=1.92-133.46, p=0.010) and poor differentiation (aOR 5.27, 95%CI=0.90-30.86, p=0.066). Negative staining tumors tended to be poorly differentiated (aOR 24.71, 95%CI=1.53-399.33, p=0.024) and were less likely to be HPV-positive (aOR 0.043, 95%CI=0.001-1.59, p=0.087). NOTCH1 mutagenesis was significantly associated with HPV status, with NOTCH1-wild-type tumors more likely to be HPV-positive than NOTCH1-mutated tumors (aOR 19.06, 95%CI=1.31-276.15, p=0.031). TP53 disruptive mutations were not associated with NICD1 expression or NOTCH1 mutation. In conclusion, NICD1 is expressed in three distinct patterns in HNSCC that are significantly associated with high-risk features. These findings further support a dual role for NOTCH1 as both tumor suppressor and oncogene in HNSCC. Further research is necessary to clarify the role of NOTCH1 in HNSCC and understand the clinical and therapeutic implications therein. Copyright © 2015, American Association for Cancer Research.
    Cancer prevention research (Philadelphia, Pa.). 01/2015;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Exposure to toxicants leads to cumulative molecular changes that over time increase a subject's risk of developing urothelial carcinoma (UC). To assess the impact of arsenic exposure at a time progressive manner, we developed and characterized a cell culture model and tested a panel of miRNAs in urine samples from arsenic exposed subjects, UC patients and controls. To prepare an in vitro model, we chronically exposed an immortalized normal human bladder cell line (HUC1) to arsenic. Growth of the HUC1 cells was increased in a time dependent manner after arsenic treatment and cellular morphology was changed. In soft agar assay, colonies were observed only in arsenic treated cells and the number of colonies gradually increased with longer periods of treatment. Similarly, invaded cells in invasion assay were observed only in arsenic treated cells. Withdrawal of arsenic treatment for 2.5 months did not reverse the tumorigenic properties of arsenic treated cells. Western blot analysis demonstrated decreased PTEN and increased AKT and mTOR in arsenic treated HUC1 cells. Levels of miR-200a, miR-200b, and miR-200c were down-regulated in arsenic exposed HUC1 cells by quantitative RT-PCR. Furthermore, in human urine, miR-200c and miR-205 were inversely associated with arsenic exposure (P=0.005 and 0.009, respectively). Expression of miR-205 discriminated cancer cases from controls with high sensitivity and specificity (AUC=0.845). Our study suggests that exposure to arsenic rapidly induces a multifaceted dedifferentiation program and miR-205 has potential to be used as a marker of arsenic exposure as well as a maker of early UC detection. Copyright © 2015, American Association for Cancer Research.
    Cancer prevention research (Philadelphia, Pa.). 01/2015;
  • [Show abstract] [Hide abstract]
    ABSTRACT: A combination of cetuximab and sorafenib in patients with recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) were assessed for potential benefit. In a randomized phase II study, R/M HNSCC patients were treated with cetuximab 400mg/m(2) IV on day 1 followed by 250mg/m(2) IV weekly (Arm A), or cetuximab at the same dose/schedule plus sorafenib 400mg PO twice-a-day (Arm B). Each cycle was 21days. Tumor p16 and HPV status, and plasma immunomodulatory cytokine levels were assessed. Of 55 patients enrolled (Arm A-27, Arm B-28), 52 patients received assigned treatments and 43 were evaluable for response. Overall response rate was 8% for both arms. Median overall survival (OS) and progression-free survival (PFS) were 9.0 and 3.0months in Arm A, and 5.7 and 3.2months in Arm B, respectively. Forty-four patients had tumors available for p16 staining (35-negative, 9-positive). Three of nine p16-positive tumors were also HPV positive. The p16-negative patients had significantly better PFS compared to the p16-positive patients (3.7 vs. 1.6months; p-value: 0.03), regardless of study arms. Twenty-four plasma samples were tested for 12 cytokine levels and patients with higher TGFβ1 levels had inferior PFS compared to lower levels (1.9 vs. 4.7months; adjusted p-value: 0.015), regardless of study arms. A subset of R/M patients with p16-negative tumors or lower plasma TGFβ1 levels had longer PFS given the cetuximab-based therapy. However, both arms showed only modest response and sorafenib given with cetuximab did not demonstrate clinical benefit. Copyright © 2014 Elsevier Ltd. All rights reserved.
    Oral oncology. 01/2015;
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    PLoS ONE 12/2014; 9(12):e113546. · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Disruption of NOTCH1 signaling was recently discovered in head and neck cancer. This study aims to evaluate NOTCH1 alterations in the progression of oral squamous cell carcinoma (OSCC) and compare the occurrence of these mutations in Chinese and Caucasian populations. We used a high-throughput-PCR-based enrichment technology and next generation sequencing (NGS) to sequence NOTCH1 in 144 samples collected in China. Forty nine samples were normal oral mucosa from patients undergoing oral surgery, 45 were oral leukoplakia biopsies and 50 were chemoradiation naïve OSCC samples with 22 paired-normal tissues from the adjacent unaffected areas. NOTCH1 mutations were found in 54% of primary OSCC and 60% of pre-malignant lesions. Importantly, almost 60% of leukoplakia patients with mutated NOTCH1 carried mutations that were also identified in OSCC, indicating an important role of these clonal events in the progression of early neoplasms. We then compared all known NOTCH1 mutations identified in Chinese OSCC patients with those reported in Caucasians to date. Although we found obvious overlaps in critical regulatory NOTCH1 domains alterations and identified specific mutations shared by both groups, possible gain-of-function mutations were predominantly seen in Chinese population. Our findings demonstrate that pre-malignant lesions display NOTCH1 mutations at an early stage and are thus bona fide drivers of OSCC progression. Moreover, our results reveal that NOTCH1 promotes distinct tumorigenic mechanisms in patients from different ethnical populations. Copyright © 2014, American Association for Cancer Research.
    Cancer Prevention Research 11/2014; · 5.27 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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 3263 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.This article is protected by copyright. All rights reserved
    Proteomics 10/2014; · 3.97 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: ABSTRACT Aim: 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. Results: 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%. Conclusion: Global and gene-specific DNA methylation may be useful biomarkers for GBC clinical assessment.
    Future Oncology 07/2014; 11(2). · 2.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    International Journal of Molecular Medicine 07/2014; · 1.88 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: By a candidate gene approach, we analyzed the promoter methylation (PM) of 8 genes genes (ARF, TIMP3, RAR-β2, NID2, CCNA1, AIM1, CALCA and CCND2) by quantitative methylation specific PCR (QMSP) in 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 any one of the 3 markers methylation 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.
    Oncotarget 06/2014; · 6.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    Cancer Research 05/2014; · 9.28 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    Oncology Reports 05/2014; · 2.19 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: To identify new epigenetic markers and further characterize Urothelial Cell Carcinoma (UCC), we tested the promoter methylation (PM) status of 19 genes previously identified as cancer specific methylated genes in other solid tumors. Methods: We used bisulfite sequencing, methylation specific PCR and quantitative methylation specific PCR (QMSP) to test the PM status of 19 genes in urothelial cancer cell lines. Results: Among the 19 genes tested, VGF was found to be completely methylated in several UCC cell lines. VGF QMSP analysis showed that methylation values of almost all the primary 19 UCC tissues were higher than the paired normal tissues (P=0.009). In another cohort, 12/35 (34.3%) of low grade UCC cases displayed VGF methylation. As a biomarker for non-invasive detection of UCC, VGF showed a significantly higher frequency of methylation in urine from UCC cases (8/20) compared to controls (1/20) (P=0.020). After treatment of cell lines with 5-Aza-2'-deoxycytidine, VGF was robustly re-expressed. Forced expression of VGF in bladder cancer cell lines inhibited cell growth. Conclusion: Selection of candidates from genome-wide screening approach in other solid tumors successfully identified UCC specific methylated genes.
    Oncotarget 05/2014; · 6.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Tumor suppressor genes (TSGs) are commonly inactivated by somatic mutation and/or promoter hypermethylation; 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.
    Epigenetics: official journal of the DNA Methylation Society 05/2014; 9(7). · 5.11 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Recurrent Prostate cancer remains a major problem, where staging, grading and prostate-specific antigen (PSA) level at the time of surgery are helpful, but still imperfect predictors for recurrence. For this reason, there is an imperative need of additional biomarkers that add to the prediction of the currently used prognostic factors. We evaluated the extent of promoter methylation of genes previously reported as aberrantly methylated in prostate cancer (PCa) (AIM1, APC, CCND2, GPX3, GSTP1, MCAM, RARβ2, SSBP2 and TIMP3), by quantitative fluorogenic methylation-specific PCR (QMSP) using 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 extent of methylation and risk of recurrence was estimated using logistic regression adjusting for prostatectomy age, year, stage, grade, surgical margins, and pre-prostatectomy PSA concentration. All statistical tests were two-sided, and p<0.05 was considered to be statistically significant. GSTP1 methylation extent was higher in recurrence cases than in controls (p = 0.01), especially in patients with early disease (i.e., organ-confined or limited extra-prostatic extension) (p = 0.001). After multivariable adjustment, having at or above the median extent of GSTP1 promoter methylation was associated with an increased risk of recurrence, including in men with early disease (both p = 0.05). Greater GSTP1 promoter methylation in cancer tissue was independently associated with risk of recurrence in patient with early prostate cancer, suggesting its testing as a potential tissue-based recurrence marker.
    The Journal of urology 04/2014; · 3.75 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND Patients with advanced, metastatic sarcoma have a poor prognosis, and the overall benefit from the few standard-of-care therapeutics available is small. The rarity of this tumor, combined with the wide range of subtypes, leads to difficulties in conducting clinical trials. The authors previously reported the outcome of patients with a variety of common solid tumors who received treatment with drug regimens that were first tested in patient-derived xenografts using a proprietary method (“TumorGrafts”).METHODS Tumors resected from 29 patients with sarcoma were implanted into immunodeficient mice to identify drug targets and drugs for clinical use. The results of drug sensitivity testing in the TumorGrafts were used to personalize cancer treatment.RESULTSOf 29 implanted tumors, 22 (76%) successfully engrafted, permitting the identification of treatment regimens for these patients. Although 6 patients died before the completion of TumorGraft testing, a correlation between TumorGraft results and clinical outcome was observed in 13 of 16 (81%) of the remaining individuals. No patients progressed during the TumorGraft-predicted therapy.CONCLUSIONS The current data support the use of the personalized TumorGraft model as an investigational platform for therapeutic decision-making that can guide treatment for rare tumors such as sarcomas. A randomized phase 3 trial versus physician's choice is warranted. Cancer 2014. © 2014 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society.
    Cancer 04/2014; · 5.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: KRAS gene mutation is linked to poor prognosis and resistance to therapeutics in Non Small Cell Lung Cancer (NSCLC). In this study, we have explored the possibility of exploiting inherent differences in KRAS mutant cell metabolism for treatment. This study identified a greater dependency on folate metabolism pathways in KRAS mutant compared to KRAS wild type NSCLC cell lines. Microarray gene expression and biological pathway analysis identified higher expression of folate metabolism and purine synthesis related pathways in KRAS mutant NSCLC cells compared to wildtype counterparts. Moreover, pathway analysis and knockdown studies suggest a role for MYC transcriptional activity in the expression of these pathways in KRAS mutant NSCLC cells. Furthermore, KRAS knockdown and overexpression studies demonstrated the ability of KRAS to regulate expression of genes that comprise folate metabolism pathways. Proliferation studies demonstrated higher responsiveness to methotrexate, pemetrexed and other antifolates in KRAS mutant NSCLC cells. Surprisingly, KRAS gene expression is downregulated in KRAS wildtype and KRAS mutant cells by antifolates which may also contribute to higher efficacy of antifolates in KRAS mutant NSCLC cells. In vivo analysis of multiple tumorgraft models in nude mice identified a KRAS mutant tumor among the pemetrexed responsive tumors and also demonstrated an association between expression of folate pathway gene, Methylenetetrahydrofolate Dehydrogenase 2 (MTHFD2), and antifolate activity. Collectively, we identify altered regulation of folate metabolism in KRAS mutant NSCLC cells that may account for higher antifolate activity in this subtype of NSCLC.
    Molecular Cancer Therapeutics 03/2014; · 5.60 Impact Factor
  • Source
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Current technology permits an unbiased massive analysis of so-matic genetic alterations from tumor DNA as well as the generation of individu-alized mouse xenografts (Avatar models). This work aimed to evaluate our ex-perience integrating these two strategies to personalize the treatment of cancer patients. Methods: 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 has 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. In occasions 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 promising 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.
    Clinical Cancer Research 03/2014; · 8.19 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    Oncoscience. 01/2014; 1(11):725-37.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The majority of the epigenomic reports in hepatocellular carcinoma have focused on identifying novel differentially methylated drivers or passengers of the oncogenic process. Few reports have considered the technologies in place for clinical translation of newly identified biomarkers. The aim of this study was to identify epigenomic technologies that need only a small number of samples to discriminate HCC from non-HCC tissue, a basic requirement for biomarker development trials. To assess that potential, we used quantitative Methylation Specific PCR, oligonucleotide tiling arrays, and Methylation BeadChip assays. Concurrent global DNA hypomethylation, gene-specific hypermethylation, and chromatin alterations were observed as a hallmark of HCC. A global loss of promoter methylation was observed in HCC with the Illumina BeadChip assays and the Nimblegen oligonucleotide arrays. HCC samples had lower median methylation peak scores and a reduced number of significant promoter-wide methylated probes. Promoter hypermethylation of RASSF1A, SSBP2, and B4GALT1 quantified by qMSP had a sensitivity ranging from 38% to 52%, a specificity of 100%, and an AUC from 0.58 to 0.75. A panel combining these genes with HCC risk factors had a sensitivity of 87%, a specificity of 100%, and an AUC of 0.91.
    Gastroenterology Research and Practice 01/2014; 2014:597164. · 1.50 Impact Factor

Publication Stats

17k Citations
2,708.00 Total Impact Points

Institutions

  • 1994–2015
    • Johns Hopkins University
      • • Department of Medicine
      • • Department of Otolaryngology - Head and Neck Surgery
      Baltimore, Maryland, United States
  • 1994–2014
    • Johns Hopkins Medicine
      • • Department of Otolaryngology - Head and Neck Surgery
      • • Department of Pathology
      • • Department of Pediatric Neurology
      • • Department of Urology
      Baltimore, Maryland, United States
  • 2013
    • Universidad de La Frontera
      Ciudad Temuco, Araucanía, Chile
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea
    • Istanbul University
      İstanbul, Istanbul, Turkey
  • 2012–2013
    • Brazilian National Cancer Institute
      Rio de Janeiro, Rio de Janeiro, Brazil
    • Virginia Commonwealth University
      • Department of Human and Molecular Genetics
      Richmond, VA, United States
  • 2011
    • Greater Baltimore Medical Center
      Baltimore, Maryland, United States
  • 2008
    • University of North Carolina at Chapel Hill
      • Department of Otolaryngology/Head and Neck Surgery
      Chapel Hill, NC, United States
    • Asan Medical Center
      • Department of Pathology
      Seoul, Seoul, South Korea
    • University of Ulsan
      • College of Medicine
      Urusan, Ulsan, South Korea
  • 2005–2008
    • National Institute of Standards and Technology
      • Biochemical Science Division
      Gaithersburg, MD, United States
  • 2002–2008
    • Instituto Português de Oncologia
      • Department of Pathology
      Oporto, Porto, Portugal
  • 2000–2007
    • The Australian Society of Otolaryngology Head & Neck Surgery
      Evans Head, New South Wales, Australia
    • National Defense Medical College
      • Department of Otolaryngology
      Tokorozawa, Saitama-ken, Japan
  • 2004
    • Wayne State University
      • Department of Otolaryngology, Head and Neck Surgery
      Detroit, MI, United States
  • 2003
    • University of Rochester
      • Department of Surgery
      Rochester, NY, United States
  • 2001
    • Dong-Pusan College
      Tsau-liang-hai, Busan, South Korea
  • 1998
    • University of Maryland, Baltimore
      Baltimore, Maryland, United States