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  • American Association for Cancer Research (AACR)  (9)
  • Shen, Li  (9)
  • Tong, Pan  (9)
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  • American Association for Cancer Research (AACR)  (9)
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  • 1
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 76, No. 14_Supplement ( 2016-07-15), p. 393-393
    Abstract: Recently published whole exome sequencing studies in head and neck squamous cell carcinoma (HNSCC) tumors revealed that few had therapeutically targetable alterations using current strategies. This finding defines translational gap between genomics and HNSCC treatment. One potential targetable alteration is PIK3CA mutations. However, clinical trials testing PI3K/mTOR pathway inhibitors have had limited success and these inhibitors only lead to cell cycle arrest in PIK3CA mutant HNSCC cell lines. Thus, there is a critical need to identify therapeutic vulnerabilities for common mutation groups, including tumor suppressors, in HNSCC. One of these molecular subgroups is NOTCH1 which is the second most frequently mutated gene in HNSCC, with a 10-15% prevalence of inactivating mutations. Although there are several studies underscoring the importance of NOTCH1 as a tumor suppressor in HNSCC, none has identified a therapy that targets NOTCH1 mutant (mut) HNSCC. Our objective was to identify predictive biomarkers of sensitivity to PI3K/mTOR inhibitors by integrating drug and multiple-omics data. Cell viability with six PI3K/mTOR inhibitors in 68 HNSCC lines was measured by the CellTiter Glo assay. The peak plasma concentration of each drug was used as the cut-off to determine sensitivity. We observed a striking correlation between NOTCH1mut and sensitivity to PI3K/mTOR pathway inhibitors. When fisher's exact test was performed, NOTCH1mut lines were more sensitive to GSK2126458 (P & lt;0.027), BYL719 (P & lt;0.004) and PQR309 (P & lt;0.014) than NOTCH1 wild type cell lines. NOTCH1 was also identified as an upstream regulator in sensitive cell lines by Ingenuity® Pathway Analysis. Basal NOTCH1 protein expression was higher in HNSCC lines resistant to PI3K/mTOR inhibition using unsupervised hierarchical clustering of Reverse Phase Protein Array data. NOTCH1mut lines underwent more apoptosis after GSK2126458 treatment compared to NOTCH1wt lines (PCI15B- 48.1 fold; P & lt;0.05, HN31- 46.9 fold; P & lt;0.05). There was also increased accumulation of cells in G1 after GSK2126458 treatment in NOTCH1mut lines (PCI15B-1.3 fold, P & lt;0.05; HN31- 1.4 fold, P & lt;0.05). To check if inhibition of NOTCH1 pathway inhibition sensitizes NOTCH1wt lines to PI3K/mTOR inhibition, resistant NOTCH1wt lines were treated with Gamma secretase inhibitors and GSK2126458. The combination led to significantly decreased cell viability (DAPT- 1.5 fold and YO010227- 1.7 fold). The combination studies will be further expanded to 38 NOTCH1wt lines. On-going studies include assessment of drug sensitivity in vivo, mechanistic studies and the effect of genetic manipulation of NOTCH1 signaling on sensitivity to PI3K/mTOR inhibitors. Our data suggests that loss of active NOTCH1 signaling confers sensitivity to PI3K/mTOR inhibition. If the combination of NOTCH1 and PI3K/mTOR inhibition leads to apoptosis, this combination could be translated into the clinic. Citation Format: Faye M. Johnson, Vaishnavi Sambandam, Li Shen, Ming Zhang, Rishi Saigal, Pan Tong, Tuhina Mazumdar, Lauren A. Byers, Curtis Pickering, Jeffrey N. Myers, Jing Wang, Mitchell Frederick. NOTCH1 inactivating mutation mediates sensitivity to PI3K/mTOR inhibitors in head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 393.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
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    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2016
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  • 2
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 78, No. 13_Supplement ( 2018-07-01), p. 2977-2977
    Abstract: Genomic alterations in the PI3K/mTOR pathway occur in 54% of HNSCC patients. To identify novel biomarkers of response to PI3K/mTOR pathway inhibitors in HNSCC, we tested the efficacy of 7 PI3K/mTOR pathway inhibitors in 59 HNSCC cell lines and determined the association between drug sensitivity and genomic alterations. We identified that NOTCH1mut lines were significantly more sensitive to PI3K/mTOR pathway inhibitors than NOTCHWT lines: GSK2126458 (12/14 NOTCH1Mut lines), BYL719 (6/14), PQR309 (12/14), BKM120 (14/16), BEZ235 (12/16), BAY806942 (13/14) and GDC0980 (5/14 lines). In contrast to PIK3CAmut cell lines that experienced cell cycle arrest, after PI3K/mTOR pathway inhibition, NOTCH1mut lines underwent significant apoptosis in addition to G1/S cell cycle arrest. NOTCH1mut lines also showed reduced clonogenic growth in vitro and tumor growth inhibition in vivo in both oral orthotopic and subcutaneous xenograft mouse models. NOTCH1 knock out (KO) by CRISPR-Cas9 system in a NOTCH1WT line (PJ34) rendered it more sensitive to PI3K/mTOR inhibition. After PI3K/mTOR inhibition, PJ34-NOTCH1 KO showed significant reduction in clonogenic growth (1.57-fold; P & lt;0.05) and increased apoptosis (4.3-fold; P & lt;0.05) compared to the parental line. As no canonical pathways account for the underlying mechanism of sensitivity, we measured the level of 301 proteins by reverse phase protein array (RPPA) in 3 NOTCH1mut and 3 NOTCH1WT lines after GSK2126458 treatment. Several proteins related to cell cycle were differentially regulated in NOTCH1mutcells compared to wild type lines. Notably, both mRNA and protein levels of Aurora B were significantly decreased in NOTCH1mutcells but not in NOTCHwt cells following PI3K/mTOR inhibition. Aurora B is an important cell cycle regulator and deregulation of Aurora kinases leads to defective chromosomal segregation and mitotic catastrophe in numerous cancers. Aurora kinase inhibitors as single agent are highly effective in a panel of NOTCHwt cell lines as demonstrated by decreased colony formation ability and proliferation as well as G2/M arrest and apoptosis. Inhibition of Aurora kinases in combination with PI3K inhibitors displayed synergy (Combination Index & lt;1) in 64% of NOTCH1 wild type lines (26/44) and 66% of NOTCH1mutcell lines (8/12) also exhibited increased sensitivity as assessed by Cell-titer Glo assay. Aurora B knock down and over expression studies are underway to validate the finding. This work is significant because inactivating NOTCH1 mutations, which occur in 18% of HNSCC patients and SCCs of the lung, esophagus, and other sites, may serve as a biomarker for response. Our present work may uncover potential combination therapies for HNSCC. Citation Format: Vaishnavi Sambandam, Li Shen, Pan Tong, Shaohua Peng, Tuhina Mazumdar, Ratnakar Singh, Curtis R. Pickering, Jeffrey N. Myers, Jing Wang, Mitchell Frederick, Faye M. Johnson. PI3K/mTOR pathway inhibition induces Aurora B mediated cell death in NOTCH1 mutant head and neck squamous (HNSCC) cells [abstract] . In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2977.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2018
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  • 3
    In: Molecular Cancer Research, American Association for Cancer Research (AACR), Vol. 18, No. 10_Supplement ( 2020-10-01), p. B19-B19
    Abstract: Genomic alterations in the PI3K/mTOR pathway occur in 54% of head and neck squamous cell carcinoma (HNSCC) patients. To identify novel biomarkers of response to PI3K/mTOR pathway inhibitors in HNSCC, we tested the efficacy of seven PI3K/mTOR pathway inhibitors in 59 HNSCC cell lines and determined the association between drug sensitivity and genomic alterations. We identified that NOTCH1MUT lines were significantly sensitive to the following PI3K/mTOR pathway inhibitors: GSK2126458 (12/14 lines), BYL719 (6/14), PQR309 (12/14), BKM120 (14/16), BEZ235 (12/16), BAY806942 (13/14), and GDC0980 (5/14). In contrast to PIK3CAMUT cell lines, NOTCH1MUT lines underwent significant apoptosis in addition to G1/S cell cycle arrest after PI3K/mTOR pathway inhibition. NOTCH1MUT lines also showed significantly reduced clonogenic growth in vitro and significant tumor growth inhibition in vivo in both oral orthotopic and subcutaneous xenograft mouse models. We employed CRISPR-Cas9 gene editing technology to knock out NOTCH1 gene in two NOTCH1WT lines, PJ34 and UMSCC49. After GSK2126458 treatment, NOTCH1-KO lines showed decreased cell viability compared to parental lines. Both NOTCH1 KO lines also showed increased cleaved PARP and cleaved caspase 3 by Western blot analysis after PI3K/mTOR inhibition. With GSK2126458 and BEZ235 treatment, both PJ34 and UMSCC49 NOTCH1 knock out lines showed significantly decreased number of colonies compared to the parental lines. As no canonical pathways account for the underlying mechanism of sensitivity, we measured the level of 301 proteins by reverse phase protein array (RPPA) in three NOTCH1MUT and three NOTCH1WT lines after GSK2126458 treatment. Several proteins were differentially regulated in NOTCH1MUT cells compared with wild-type lines including PDK1, FoxM1 and phospho-ERK. We then investigated PDK1 because it is activated by PI3K and can regulate FOXM1, ERK, and p70 ribosomal protein S6 kinase (p70S6K), which were also inhibited more robustly in NOTCH1MUT HNSCC. To test the role of PDK1 in PI3K/mTOR inhibition, we overexpressed PDK1 in NOTCH1MUT cells and the presence of PDK1-GFP was confirmed by Western blot analysis. PDK1 overexpression in NOTCH1MUT cells successfully led to decreased apoptosis after GSK2126458 treatment as compared to the parental lines. The combination of AKT and PDK1 inhibition led to decreased cell viability in all four NOTCH1WT lines tested as compared to single agents. The combination also led to significantly increased apoptosis in all NOTCH1WT cell lines tested as demonstrated by cleaved PARP and cleaved Caspase 3 levels by Western blot analysis. This work is significant because inactivating NOTCH1 mutations, which occur in 18% of HNSCC patients and in squamous cell carcinomas of the lung, esophagus, and other sites, may serve as a biomarker for response. Our present work may uncover important combination therapies for HNSCC. Citation Format: Vaishnavi Sambandam, Mitchell J. Frederick, Li Shen, Pan Tong, Xiayu Rao, Shaohua Peng, Tuhina Mazumdar, Quili Li, Curtis R. Pickering, Jeffery N. Myers, Jing Wang, Faye M. Johnson. Susceptibility of NOTCH1 mutant head and neck squamous carcinoma to PI3K/mTOR pathway inhibition via PDK1 [abstract]. In: Proceedings of the AACR Special Conference on Targeting PI3K/mTOR Signaling; 2018 Nov 30-Dec 8; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(10_Suppl):Abstract nr B19.
    Type of Medium: Online Resource
    ISSN: 1541-7786 , 1557-3125
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2020
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  • 4
    In: Clinical Cancer Research, American Association for Cancer Research (AACR), Vol. 25, No. 11 ( 2019-06-01), p. 3329-3340
    Abstract: Head and neck squamous cell carcinoma (HNSCC) is driven largely by the loss of tumor suppressor genes, including NOTCH1, but lacks a biomarker-driven targeted therapy. Although the PI3K/mTOR pathway is frequently altered in HNSCC, the disease has modest clinical response rates to PI3K/mTOR inhibitors and lacks validated biomarkers of response. We tested the hypothesis that an unbiased pharmacogenomics approach to PI3K/mTOR pathway inhibitors would identify novel, clinically relevant molecular vulnerabilities in HNSCC with loss of tumor suppressor function. Experimental Design: We assessed the degree to which responses to PI3K/mTOR inhibitors are associated with gene mutations in 59 HNSCC cell lines. Apoptosis in drug-sensitive cell lines was confirmed in vitro and in vivo. NOTCH1 pathway components and PDK1 were manipulated with drugs, gene editing, knockdown, and overexpression. Results: PI3K/mTOR inhibition caused apoptosis and decreased colony numbers in HNSCC cell lines harboring NOTCH1 loss-of-function mutations (NOTCH1MUT) and reduced tumor size in subcutaneous and orthotopic xenograft models. In all cell lines, NOTCH1MUT was strongly associated with sensitivity to six PI3K/mTOR inhibitors. NOTCH1 inhibition or knockout increased NOTCH1WT HNSCC sensitivity to PI3K/mTOR inhibition. PDK1 levels dropped following PI3K/mTOR inhibition in NOTCH1MUT but not NOTCH1WT HNSCC, and PDK1 overexpression rescued apoptosis in NOTCH1MUT cells. PDK1 and AKT inhibitors together caused apoptosis in NOTCH1WT HNSCC but had little effect as single agents. Conclusions: Our findings suggest that NOTCH1MUT predicts response to PI3K/mTOR inhibitors, which may lead to the first biomarker-driven targeted therapy for HNSCC, and that targeting PDK1 sensitizes NOTCH1WT HNSCC to PI3K/mTOR pathway inhibitors.
    Type of Medium: Online Resource
    ISSN: 1078-0432 , 1557-3265
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    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2019
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  • 5
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 77, No. 13_Supplement ( 2017-07-01), p. 2992-2992
    Abstract: Background: Genomic alterations in the PI3K/mTOR pathway occur in 54% of HNSCC patients. However, clinical trials of PI3K/mTOR pathway inhibitors had limited success even in those tumors with pathway alterations, including PIK3CA mutations. To target genomic alterations in HNSCC, we tested the efficacy of 7 PI3K/mTOR pathway inhibitors in 59 HNSCC cell lines and determined the association between drug sensitivity and molecular characteristics in order to identify biomarkers of response. Methods: We systematically analyzed the association between drug sensitivity and genomic alterations in 59 HNSCC lines. Results: NOTCH1mut lines are significantly sensitive to PI3K/mTOR pathway inhibitors: GSK2126458 (13/16), BYL719 (6/16), PQR309 (13/16), BKM120 (14/16), BEZ235 (12/16), BAY806942 (14/16) and GDC0980 (13/16 lines). In contrast to PIK3CAmut cell lines, all 7 NOTCH1mut lines tested underwent apoptosis (14.3 fld; P & lt;0.005). After PI3K/mTOR inhibition, NOTCH1mut lines showed significantly reduced clonogenic growth in vitro (0.4/ 0.9 fold in HN31/ PCI15B; P & lt;0.05) and significant tumor growth inhibition in vivo using orthotopic oral xenograft mouse models (1.7 and 2 fold in UMSCC22A and HN31; P & lt;0.01). To determine if NOTCH1 mediates resistance, we conditionally expressed cleaved NOTCH1 by Dox-inducible system in a NOTCH1mut line (UMSCC22A). This rescued PI3K/mTOR inhibitor-induced apoptosis (0.5 fold; P & lt;0.05) and reduced colony formation in vitro. As no canonical pathways account for the underlying mechanism of sensitivity, we measured the level of 301 proteins by reverse phase protein array (RPPA) in 3 NOTCH1mut and 3 NOTCH1WT lines after GSK2126458 treatment. Glutaminase and Glutamate Dehydrogenase were differentially expressed in NOTCH1mut lines. Thus, we hypothesized that PI3K/mTOR inhibition in NOTCH1mut lines induced reactive oxygen species (ROS)-mediated apoptosis via metabolic alterations. Consistent with this hypothesis, NOTCH1mut lines exhibited increased ROS production; Metabolic pathway inhibitors targeting Glycolysis, Pentose Phosphate pathway and Glutaminolysis, in combination with GSK2126458 decreased cell viability in NOTCHWT lines. Conclusion: In contrast to PIK3CAmut cells, NOTCH1mut HNSCC cells underwent apoptosis after PI3K/mTOR pathway inhibition in vitro and decreased tumor size in vivo. The ectopic activation of NOTCH1 rescued NOTCH1mut HNSCC cells from PI3K/mTOR inhibitor-mediated apoptosis. The underlying mechanism may involve differential effects on tumor metabolism and ROS production. This work is significant because inactivating NOTCH1 mutations, which occur in 18% of HNSCC patients and SCCs of the lung, esophagus, and other sites, may serve as a biomarker for response. Our future work may uncover previously unknown crosstalk between the PI3K/mTOR and NOTCH pathways in SCCs. Citation Format: Vaishnavi Sambandam, Li Shen, Pan Tong, Tuhina Mazumdar, Curtis Pickering, Jeffrey N. Myers, Jing Wang, Mitchell Frederick, Faye M. Johnson. Identification of NOTCH1 inactivating mutation as a therapeutic vulnerability to PI3K/mTOR pathway inhibition in head and neck squamous cell carcinoma (HNSCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2992. doi:10.1158/1538-7445.AM2017-2992
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
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    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2017
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  • 6
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    Online Resource
    American Association for Cancer Research (AACR) ; 2017
    In:  Cancer Research Vol. 77, No. 13_Supplement ( 2017-07-01), p. 4095-4095
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 77, No. 13_Supplement ( 2017-07-01), p. 4095-4095
    Abstract: Background: Inhibiting polo-like kinase 1 PLK1 may be an effective treatment for non-small cell lung cancer (NSCLC). PLK1 is a key regulator of mitosis and DNA damage checkpoints. PLK1 inhibitors are well tolerated, but only a few unselected patients with NSCLC respond to single-agent therapy. However, predictive biomarkers have not been used to select patients who are likely to experience a response to PLK1 inhibitors, and the mechanisms of resistance to PLK1 inhibitors have not been elucidated, making these unknowns a major gap in knowledge. To address this gap, we compared basal gene and protein expression in 63 NSCLC cell lines and discovered that mesenchymal NSCLC cell lines were more sensitive to PLK1 inhibitors than epithelial cell lines in vitro and in vivo. The induction of apoptosis in some NSCLC cell lines at very low drug concentrations and the need to find better therapy for mesenchymal NSCLC motivated us to further study PLK1 inhibition. Methods: To identify the pathways involved in PLK1 inhibitor-induced apoptosis, we used 3 pairs of isogenic NSCLC cell lines in which we had induced a mesenchymal phenotype using TGF-β. These isogenic lines were treated with the PLK1 inhibitor (volasertib) for 24 hours and levels of 301 proteins and phosphoproteins were simultaneously measured before and after treatment with volasertib using reverse phase protein array (RPPA). Results: The induction of a mesenchymal phenotype using TGF-β increased PLK1 inhibition-induced DNA damage and apoptosis in 3 NSCLC cell lines. To further elucidate mechanisms of resistance to PLK1 inhibition, we compared gene and protein expression in these isogenic cell lines, before and after PLK1 inhibition. There were 35, 12 and 43 proteins differentially regulated following PLK1 inhibition in epithelial vs. mesenchymal lines in HCC366, H1975, and HCC4006 cell lines, respectively at False Discovery rate 0.1. Phosphorylated FAK (Y397) and c-Met (Y1234/1235) were consistently inhibited following PLK1 inhibition in the mesenchymal lines but activated in the epithelial lines. These changes were confirmed by Western blotting. Total FAK and c-Met protein and mRNA levels were not affected, demonstrating post-translational changes. The inhibition of c-Met using EMD 1214063 led to FAK inhibition but FAK inhibition did not affect c-Met activation. The combination of c-Met inhibitor and volasertib increases sensitivity in NSCLC cell lines tested. The combinations led to more apoptosis than the single-agent inhibitors. Conclusions: NSCLC cell lines have diverse sensitivities to PLK1 inhibition, which is consistent with the results of clinical trials of PLK1 inhibitors in solid tumors, but no studies to date explain these diverse responses to PLK1 inhibition. We have identified c-Met activation as a previously unknown pathway of resistance to PLK1 inhibition in epithelial NSCLC. Citation Format: Ratnakar Singh, Li Shen, Pan Tong, Jing Wang, Faye M. Johnson. c-Met activation mediates resistance to polo-like kinase 1 inhibitor-induced apoptosis in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4095. doi:10.1158/1538-7445.AM2017-4095
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
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    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2017
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  • 7
    Online Resource
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    American Association for Cancer Research (AACR) ; 2016
    In:  Cancer Research Vol. 76, No. 14_Supplement ( 2016-07-15), p. 3793-3793
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 76, No. 14_Supplement ( 2016-07-15), p. 3793-3793
    Abstract: High-risk human papillomavirus (HPV) is an oncogenic virus associated with 90% of cervical cancers, over 60% of oropharyngeal carcinoma cases and over 90% of anogenital cancers. Although HPV-positive cancers are molecularly, clinically and epidemiologically distinct from HPV-negative cancers, there are no specific or targeted therapies for HPV-positive cancers. In order to identify small molecule inhibitors that target HPV-positive cancers, we performed a high throughput drug screen on 24 cervical cancer and head and neck squamous cell carcinoma (HNSCC) cell lines (12 HPV-positive and 12 HPV-negative) to determine if these cell lines display differential sensitivity based on HPV status. HPV-positive cell lines with doubling times of less than 72 hours were selected for the screen. Unsupervised clustering of HNSCC cell lines based on protein expression levels obtained from reverse phase protein array (RPPA) was used to select matched HPV-negative cell lines by Spearman's rank-order correlation. Cytotoxic chemotherapeutics and agents targeting a broad range of processes including cell cycle control and DNA damage response were obtained from commercial vendors and academic collaborators. Drug sensitivity was measured by using nuclear staining to monitor cell death and proliferation after 72h of treatment. The screen of 1062 unique compounds at 6 different concentrations (0-3μM) in 24 cell lines represents 25,448 cell line – drug interactions. To ensure the robustness and reproducibility of the screen, the Z-factor and standard deviation for biological replicates were calculated. A Z-factor greater 0.5 was considered acceptable and the mean standard deviation across all drugs for each cell line was 0.06. Drug sensitivity was determined by calculating IC50 and area under the curve (AUC) values. Overall, HPV-positive HNSCC cell lines showed greater sensitivity to 13 drugs from different classes. Particularly, HPV-positive HNSCC cells were more sensitive to p38 MAPK and B-Raf inhibitors including LY2228820 (p & lt; 0.01), regorafenib (p & lt; 0.01), sorafenib (p & lt; 0.05) and SB590885 (p & lt; 0.05). On the other hand, HPV-negative HNSCC lines showed increased sensitivity to 30 drugs among these, palbociclib (p & lt; 0.01), a CDK 4/6 inhibitor, and ryuvidine (p & lt;0.05) which is reported to inhibit CDK 4. We are currently in the process of performing mechanistic studies and identifying genomic characteristics that influence sensitivity to B-Raf and p38 MAPK inhibitors in HPV-associated cancers using the genomic analyses and drug sensitivity data. Given the difference in clinical outcomes based on HPV status, any validated chemical-genomic interactions we discover will provide strong support for HPV-based treatment plans that may improve efficacy, allow for dose de-escalation and prevent permanent toxicity in patients. Citation Format: Nene N. Kalu, Tuhina Mazumdar, Pan Tong, Li Shen, Jing Wang, Lauren Averett Byers, Faye M. Johnson. Cell-based, high-throughput screen for small molecule inducers of cell death in HPV-associated head and neck cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3793.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
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    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2016
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  • 8
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 76, No. 14_Supplement ( 2016-07-15), p. 4757-4757
    Abstract: Objectives: It is urgent to explore novel biomarkers and therapeutic targets for that are relevant to head and neck squamous cell carcinoma (HNSCC), which is the 6th most common cancer worldwide. Based on a prior drug screen, we identified 3 mitotic inhibitors (AZD7762, AZD1775, volasertib) as effective therapies for HNSCC. Our objective with this study is to identify mechanisms of response and potential biomarkers of response and Methods: Cell viability assays were performed by the CellTiter-Glo Luminescent method in a panel of 68 fingerprinted HNSCC cell lines using the 3 drugs at concentrations of 0.018 to 9.613 μM. Cell cycle, apoptosis and altered pathway protein expression after cells treated by the polo-like kinase 1 (PLK1) inhibitor volasertib were investigated by FACS, TUNEL and western blots respectively. An orthotopic mouse model of HNSCC was used to confirm the antitumor effects of PLK1 inhibition in vivo. To determine the mechanisms of drug sensitivity, we analyzed the correlation between gene expression, protein expression, gene mutation and drug sensitivity using modified two-sample t-tests were performed. The beta-uniform mixture (BUM) model was used to control false discovery rate (FDR). For correlations between drug sensitivity and gene mutations, we performed Fisher's exact test. Results: Using the IC80 values with the peak plasma concentration of each drug as the cut-off to determine sensitivity, 34, 44 and 20 HNSCC cell lines were sensitive AZD1775 (Wee inhibitor), AZD7762 (CHK1/2 inhibitor) and volasertib (PLK1 inhibitor) respectively. HNSCC harboring AJUBA mutations were more sensitive to these 3 inhibitors and those with RAS mutations more resistant. PLK1 inhibition led to G2/M arrest, but only sensitive cell lines underwent substantial apoptosis following PLK1 inhibition. Decreases of the levels of phosphorylated TCTP were observed following treatment with volasertib confirming PLK1 inhibition. There was a significant decrease of tumor volumes and prolongation of survival in the mice bearing orthotopic HNSCC tumors treated with volasertib in vivo. Conclusions: PLK1 inhibition was an effective therapy in vitro and in vivo models of HNSCC. We identified the AJUBA and RAS mutations as potential candidate biomarkers of response to these mitotic inhibitors in HNSCC. This study identified the therapeutic potential of PLK1 as a novel therapeutic target for HNSCC. Citation Format: Ming Zhang, Shaohua Peng, Tuhina Mazumdar, Vaishnavi Sambandam, Li Shen, Pan Tong, Lerong Li, Lauren Byers, Curtis Pickering, Mitchell Frederick, Jeffrey N. Myers, Jing Wang, Faye M. Johnson. Identification of biomarkers that predict response of head and neck squamous cell carcinoma to mitotic inhibitors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4757.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
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    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2016
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  • 9
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 78, No. 13_Supplement ( 2018-07-01), p. 4646-4646
    Abstract: Purpose. To address the unmet need for biomarker-driven, effective, targeted therapy for human papillomavirus (HPV)-associated head and neck squamous cell carcinoma (HNSCC) and cervical epithelial squamous cell carcinoma (CESC), we conducted a high-throughput drug screen (HTDS) using 1122 compounds in all readily available HPV-positive HNSCC and CESC cell lines and an equal number of matched HPV-negative lines. Methods. Cells were incubated in drug concentrations ranging from 0.01 μM to 3.16 μM for 72 h, fixed and stained with DAPI, and counted. Of the 1122 analyzable compounds, 865 unique drugs were tested because of overlap. All drugs were assigned to one of 36 classes based on their primary targets. Drug concentrations resulting in a 50% reduction in cell proliferation (GI50) and the area under the dose response curve were calculated. Two biological replicates were performed for all cell lines on separate days and at least 1 week apart. Results. The HTDS was conducted using 24 cell lines. We identified 493 highly effective compounds, which we defined as those with GI50 values less than 0.5 μM in 2 or more of the cell lines screened. The most effective drug classes were inhibitors of polo-like kinase, proteasomes, histone deacetylase, and Aurora kinases. Of the 19 Aurora kinase inhibitors tested, 18 were highly effective. We confirmed the efficacy of 3 Aurora kinase inhibitors using colony formation assays in 15 cell lines. Treatment with a dual Aurora A/B inhibitor, danusertib, led to G2M arrest and apoptosis in all 6 tested cell lines. Additionally, danusertib treatment decreased tumor size compared to controls in patient-derived xenograft mouse models of HNSCC. To identify biomarkers predicting response to Aurora kinase inhibitors, we tested for associations between mutations in the cell lines and sensitivity to the Aurora kinase inhibitors using whole exome mutation data for the 50 most common driver mutations in HNSCC. To validate our findings in an independent dataset, we queried the Genomics of Drug Sensitivity in Cancer database. In both data sets, cancer cell lines with KMT2D (MLL2) mutations were more sensitive to Aurora kinase inhibitors than cells without mutations. KMT2D mutations are inactivating; experiments to knock down KMT2D in wild-type cell lines and assess sensitivity to Aurora kinase inhibitors are ongoing. Conclusions. We identified Aurora kinase inhibitors as effective and understudied drugs in HNSCC and CESC. These drugs cause apoptosis and cell cycle arrest in vitro and decrease tumor size in vivo. This is the first published study to demonstrate that mutations in KMT2D (MLL2), which are common in many cancers (16% HNSCC, 12% CESC), correlate with drug sensitivity in 2 independent data sets. Citation Format: Tuhina Mazumdar, Nene N. Kalu, Shaohua Peng, Pan Tong, Li Shen, Jing Wang, Jeffrey N. Myers, Curtis R. Pickering, David Brunell, Clifford C. Stephan, Faye M. Johnson. Pharmacogenomic screen identifies KMT2D mutations as a biomarker of sensitivity to Aurora kinase inhibition in head and neck and cervical squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4646.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2018
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    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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