bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract A31: Activity-based protein profiling reveals adaptive response to pharmacological MEK inhibition in KRAS mutant non-small cell lung cancer
Authors: Kim Jae-Young , Fang Bin , Welsh Eric A. , Kinose Fumi , Li Jiannong , Eschrich Steven A. , Koomen John M. , Haura Eric B. 
Published: May 2015

Abstract
KRAS mutations account for development of approximately 30% of lung adenocarcinomas. While RAF-MEK-ERK signaling cascade is a key regulator of RAS-mediated proliferation and survival, the clinical efficacy of MEK inhibitors is still underwhelming in RAS-driven cancers. We treated KRAS mutant non-small cell lung cancer (NSCLC) cell lines with two MEK inhibitors (AZD6244 and MEK162) currently in clinical development. In all cell lines tested (N=11), we failed to observe significant effects on cell viability or induction of apoptosis. Because increasing evidence indicates that cancer cells undergo adaptive proteomic rewiring in response to kinase inhibitors, we performed activity-based protein profiling (ABPP) after treating 11 KRAS mutant NSCLC cell lines with MEK inhibitors in order to identify global enzymatic changes potentially involved in these adaptive processes. Our ABPP approach employs desthiobiotin-ATP probe, which enables selective labeling of active sites in ATP-binding proteins including kinases, chaperones and metabolic enzymes. Labeled proteins were subsequently purified and analyzed by mass spectrometry-based proteomics technique. Our ABPP results revealed that MEK inhibitors increased levels of multiple receptor tyrosine kinases (RTK) including EGFR and MET. MEK inhibitors induced MET phosphorylation and EGF-mediated AKT phosphorylation was markedly enhanced in the presence of MEK inhibitors, indicating increased RTK activity in adaptive response to MEK inhibition. We also found that MEK inhibition led to increased multiple heat shock proteins including HSP90 and HSP70, suggesting the possibility of chaperone-mediated adaptive resistance. Finally, MEK inhibitors globally increased enzymes involved in glucose utilization pathways implicating metabolic alterations in adaptive response to MEK inhibition. Collectively, our systematic activity-based proteomic profiling approach provides novel insights into adaptive resistance mechanisms to MEK inhibitors, suggesting rational combination treatment strategies for KRAS mutant NSCLC. Updated works will be presented.
Citation Format: Jae-Young Kim, Bin Fang, Eric A. Welsh, Fumi Kinose, Jiannong Li, Steven A. Eschrich, John M. Koomen, Eric B. Haura. H. Activity-based protein profiling reveals adaptive response to pharmacological MEK inhibition in KRAS mutant non-small cell lung cancer. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr A31. doi: 10.1158/1557-3125.RASONC14-A31
Abstract A33: Enhancement of thymidine phosphorylase downregulation by erlotinib enhances cytotoxicity affected by tamoxifen in human non-small cell lung cancer cells
Authors: Lin Yun-Wei , Chiu Hsien-Chun , Syu Jhan-Jhang , Jian Yun-Ting , Chen Chien-Yu 
Published: May 2015

Abstract
Tamoxifen is a triphenylethylene nonsteroidal antiestrogen used worldwide as an adjuvant chemotherapeutic agent in the treatment of breast cancer. However, the molecular mechanism of tamoxifen also could induce cytotoxicity in non-small cell lung cancer (NSCLC) cells have not been proved. In this study, tamoxifen treatment inhibited cell survival in two NSCLC cells, H520 and H1975. Treatment with tamoxifen decreased TP mRNA and protein levels in an AKT inactivation-dependent manner. Furthermore, expression of constitutively active AKT (AKT-CA) vectors significantly rescued the decreased TP protein and mRNA levels in tamoxifen-treated NSCLC cells. In contrast, a combination of PI3K inhibitors (LY294002 or wortmannin) further decreased the TP expression and cell viability induced by tamoxifen. Moreover, knocking down TP expression by transfection with small interfering RNA of TP enhanced the cytotoxicity and growth inhibition of tamoxifen. Erlotinib (Tarceva, OSI-774), an orally available inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, is approved for clinical use in the NSCLC therapy. Compared to each single treatment, the combining tamoxifen with erlotinib resulted in a synergistically inhibited the cell viability and cell growth, accompanied with the reduction of phospho-AKT, phosph-ERK1/2, and TP protein levels. An enhancement of AKT or ERK1/2 activation by transfecting the cancer cells with constitutively active AKT or MKK1/2 expression vectors significantly restored the two drugs combination-reduced TP protein levels as well as cell viability. Taken together, our results suggest that the down-modulation of AKT and ERK1/2-mediated TP expression by erlotinib represents a key factor in enhancing the cytotoxic effects of tamoxifen in NSCLC cells.
Citation Format: Yun-Wei Lin, Hsien-Chun Chiu, Jhan-Jhang Syu, Yun-Ting Jian, Chien-Yu Chen. Enhancement of thymidine phosphorylase downregulation by erlotinib enhances cytotoxicity affected by tamoxifen in human non-small cell lung cancer cells. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr A33. doi: 10.1158/1557-3125.RASONC14-A33
Abstract A40: Targeting TBK1 promotes apoptosis in MEK-inhibitor resistant mutant NRAS melanoma cells
Authors: Vu Ha Linh , Aplin Andrew E. 
Published: May 2015

Abstract
Melanoma is a devastating form of skin cancer. Fifteen to twenty percent of melanoma patients have an activating mutation in the GTPase, NRAS. Despite advances in the targeted inhibitor treatment for mutant BRAF melanoma patients, the options for mutant NRAS patients remain poor. TANK-binding kinase 1 (TBK1) is an atypical IκB kinase family member that acts downstream of the RAS effector RalGEF but the role of TBK1 in melanoma is not known. We found that NRAS overexpression in wild-type NRAS melanoma cells increased TBK1 phosphorylation. In a panel of NRAS mutant melanoma cells, we characterized sensitivity to MEK inhibition in 2D as well as 3D cell cultures that mimic the dermal microenvironment. We show that there is a differential response to MEK inhibition in this panel. TBK1 inhibition, through either siRNA transfection or pharmacological inhibitors, cooperated with MEK inhibition to promote apoptosis. These effects were particularly noted in those NRAS mutant cell lines that are insensitive to MEK inhibition. By contrast, this effect was absent in melanoma cell lines wild type for NRAS. These results identify TBK1 as a downstream effector for NRAS mutant melanoma and as a potential target for use in combinatorial therapy in this subset of patients for whom current therapeutic options are limited.
Citation Format: Ha Linh Vu, Andrew E. Aplin. Targeting TBK1 promotes apoptosis in MEK-inhibitor resistant mutant NRAS melanoma cells. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr A40. doi: 10.1158/1557-3125.RASONC14-A40
Abstract A58: KRAS mutations: Variable incidences in a Brazilian cohort of 8,234 metastatic colorectal cancer patients
Authors: Aran Veronica , Vieira Fernando M. , Victorino Ana Paula , Salem Jonas H. , Zalcberg-Renault Ilana , Bonamino Martin H. , Zalis Mariano , Ferreira Carlos Gil 
Published: May 2015

Abstract
Personalised medicine is an evolving field that seeks to target cancer therapies based on unique genetic characteristics of the tumour and/or the patient. One of the most significant advances towards personalised care in the field of oncology was the establishment of KRAS gene mutation as a validated biomarker predicting efficacy in epidermal growth factor receptor (EGFR) targeted therapies in the treatment of metastatic colorectal cancer (mCRC). KRAS mutations are frequently found in CRC indicating the importance of its genotyping in the study of the molecular mechanisms behind this disease. Although major advances have occurred over the past decade, there are still important gaps in our understanding of CRC carcinogenesis, particularly whether sex-linked factors play any role. Therefore, in this study the profile of KRAS mutations in the Brazilian population was analysed by conducting direct sequencing of KRAS codons 12 and 13 belonging to 8,234 metastatic CRC patient samples from different Brazilian regions. The median age was 59 years and the overall percentage of wild-type and mutated KRAS was 66.4% and 33.6%, respectively. Interestingly, a significant difference in the percentage of mutated KRAS patients was observed between male and female (32.5% versus 34.8%, p=0.03). However, there were no differences in the distribution of any specific KRAS mutation according to gender. This is one of the largest cohorts of KRAS genotyping in CRC patients indicating a higher incidence of KRAS mutations in females compared to males.
Citation Format: Veronica Aran, Fernando M. Vieira, Ana Paula Victorino, Jonas H. Salem, Ilana Zalcberg-Renault, Martin H. Bonamino, Mariano Zalis, Carlos Gil Ferreira. KRAS mutations: Variable incidences in a Brazilian cohort of 8,234 metastatic colorectal cancer patients. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr A58. doi: 10.1158/1557-3125.RASONC14-A58
Abstract B01: Improve MEK/ERK targeting in mutant KRAS lung cancer
Authors: Chen Zhao , Weisberg Ellen , Cheng Katherine , Kung Andrew L. , Bradner James , Griffin James , Wong Kwok-Kin 
Published: May 2015

Abstract
KRAS activating mutations are detected in 30% Non-Small Cell Lung Cancer (NSCLC) cases, and represent the subset of patients with the worst prognosis. Current efforts to develop treatments for this type of lung cancer are partially focused on inhibiting the Raf/MEK/ERK signaling cascade downstream of KRAS. Inhibition of the Raf/MEK/ERK pathway results in death of many mutant KRAS-driven lung cancer cell lines in vitro, and we have previously reported a murine active Kras lung cancer model that showed significant tumor regression upon treatment with the MEK inhibitor, selumetinib, when it was combined with other agents, such as PI3K/mTOR dual inhibitor BEZ235 or the cytotoxic agent docetaxel. The activity of the latter combination was validated in a recent phase II clinical trial in NSCLC patients harboring KRAS mutations. However, the responses were not durable in either human patients or mice, as resistance develop rapidly following chronic MEK inhibition. We have developed two approaches to reduce or delay the emergence of resistant clones. First, we have identified a number of novel treatment strategies that would directly improve the initial efficacy of MEK/ERK inhibition to dramatically enhance the initial response to MEK inhibition. Second, we have designed chemical screening strategies that identify compounds that act against active Kras lung cancer independently from the Raf/MEK/ERK pathway. We are using the first approach to delay the development of chronic resistance, while using the second approach to overcome resistance to MEK/ERK inhibition.
Citation Format: Zhao Chen, Ellen Weisberg, Katherine Cheng, Andrew L. Kung, James Bradner, James Griffin, Kwok-Kin Wong. Improve MEK/ERK targeting in mutant KRAS lung cancer. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr B01. doi: 10.1158/1557-3125.RASONC14-B01
Abstract B07: Ras-driven HCCs are addicted to FoxM1
Authors: Kopanja Dragana , Pandey Akshay , Kiefer Megan , Yu Dae-Yeul , Raychaudhuri Pradip 
Published: May 2015

Abstract
Hepatocellular carcinoma (HCC) is the fifth most fatal malignancy worldwide. In the US alone, according to American Cancer Society, about 17,550 new cases and over 15,000 deaths are reported annually. The fork-head box gene FoxM1 is highly significant in that regard, as it is over-expressed in HCC, and its over-expression coincides with highly aggressive, poorly differentiated HCC. Moreover, over-expression of FoxM1 correlates with poorer overall survival after surgery. Previous work demonstrated that FoxM1 is essential for chemical carcinogen (DEN)-induced development of HCC. Since the Ras-pathway is frequently mutated in human liver cancers, we investigated the effects of FoxM1 deletion on the progression of oncogenic Ras-induced HCC. In the mouse model we used, HRas-V12 is expressed specifically in the adult liver under control of the Alb-promoter. In this mouse model, majority (80 to 90%) of the male mice develop HCC by 8/9 months of age. We crossed that transgenic line with FoxM1 fl/fl MxCre strain. The triple transgenic strain of mice allowed us to delete FoxM1 at specific times after Ras driven tumorigenesis, by i.p. injection of double-stranded RNA (polyIpolyC). We deleted FoxM1 at 8 months of age, and observed significant decrease in the number of tumor nodules per liver. Deletion of FoxM1 inhibited proliferation of the tumor cells. Surprisingly, we did not observe increase in cell death in FoxM1 deleted tumors. Because FoxM1 is over-expressed in highly aggressive, poorly differentiated liver cancers, we investigated whether FoxM1 is needed for maintenance of hepatic cancer stem cells. Interestingly, we discovered almost complete depletion of hepatic cancers stem cells, CD90+CD45- cells, in FoxM1 deleted tumors. These studies have exciting implications in further considerations of FoxM1 as a target of Ras depended malignancies.
Citation Format: Dragana Kopanja, Akshay Pandey, Megan Kiefer, Dae-Yeul Yu, Pradip Raychaudhuri. Ras-driven HCCs are addicted to FoxM1. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr B07. doi: 10.1158/1557-3125.RASONC14-B07
Abstract B09: Loss of PTEN cooperates with mutant KRAS initiating EMT and increased stemness in a mouse model of lung cancer
Authors: Malaney Prerna , Dave Vrushank 
Published: May 2015

Abstract
We have developed a preclinical model of lung cancer associated with hyper-activated PI3K/mTOR and KRAS. Non-small cell lung cancer (NSCLC) accounts for ∼80% of all lung cancers; of which &gt;50% have aberrant PI3K/AKT/mTOR signaling and ∼30% harbor oncogenic KRAS, conferring chemo/radio-resistance and poor prognosis. KRAS inhibitors are difficult to develop, and rapalogs targeting mTOR are toxic and induce compensatory activation of AKT, causing resistance to apoptosis. Hence, development of effective inhibitors of KRAS and PI3K/mTOR pathways is imperative. Further, clinical studies implicate that tumors with aberrant KRAS and PI3K/mTOR signaling are associated with epithelial-mesenchymal transition (EMT), metastasis, poor differentiation, and chemo/radio-resistance. However, molecular details of EMT mediated by KRAS and PI3K/mTOR pathway is lacking, limiting the development of drugs targeting EMT-mediators. Using a CCSP-promoter driven Cre/LoxP mediated deletion of PTEN in an oncogenic KRAS status (PTENΔΔ/KRasG12D), we have developed a preclinical mouse model of lung cancer with hyper-activation of PI3K/mTOR and KRAS pathways. Microarray based RNA profiling followed by bioinformatic analysis on PTEN-null lung epithelial cells revealed transcriptional activation of RAS/RAF/MAPK/ERK pathway associated candidate genes. On the other hand, Dox-induced PTENΔΔ/KRasG12D lung tumors showed induction of SNAIL1, SLUG, ZEB-2 and SOX2 genes. Taken together, our analysis reveals that PTEN loss predisposes lung tumors to hyper-activation of the KRAS pathway, which is further accentuated by oncogenic mutation in KRAS, initiating EMT and increased stemness.
Citation Format: Prerna Malaney, Vrushank Dave. Loss of PTEN cooperates with mutant KRAS initiating EMT and increased stemness in a mouse model of lung cancer. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr B09. doi: 10.1158/1557-3125.RASONC14-B09
Abstract B16: Activated glucocorticoid signaling in pancreatitis contributes to acinar-to-ductal metaplasia and KrasG12D-driven tumorigenesis
Authors: Shen Chia-Ning , Su Chien-Chang , Hsieh Chi-Chih , Liao Wen-Ying , Mao Wan-Yu , Shen Chia-Rui , Hsiao Michael 
Published: May 2015

Abstract
Patients with chronic pancreatitis are at increased risk of developing pancreatic cancer. However, the key inflammatory action mediating pancreatic tumorigenesis has not been clearly determined. Here, we initially identified evaluated levels of activated glucocorticoid receptors (GR) were observed in patients of chronic pancreatitis and pancreatic ductal adenocarcinomas (PDAC). Utilizing mice that conditionally expressed KrasG12D in acinar cell compartment with or without loss of GR, we demonstrated that activation of GR was required for generation of metaplastic ductal lesion and development of pancreatic intraepithelial neoplasia (PanIN) in mice with experimental pancreatitis. Administration of dexamethason, a potent synthetic glucocoticoid, was sufficient to induce development of advanced PanINs and metastatic PDACs in KrasG12D mice that harbour single-allele deletion of p53. We further revealed that nongenomic activation of GR was a key action that led to evaluating c-Src signaling and triggering a pathological threshold of Ras activity necessary for neoplastic transformation. In contrast, treatment of dasatinib, a Src kinase inhibitor, could suppressed development of PanIN and PDAC induced by dexamethasone. Importantly, cre-lox based lineage-tracing mice was applied and identified that GR activation directly transformed GFP-tagged KrasG12D-expressing acinar cells to tumorigenic cells that posse features of cancer initiating cells. The findings explained why chronic inflammation increase pancreatic cancer risk and raised concerns on the use of glucocorticoids on patients of chronic pancreatitis
Citation Format: Chia-Ning Shen, Chien-Chang Su, Chi-Chih Hsieh, Wen-Ying Liao, Wan-Yu Mao, Chia-Rui Shen, Michael Hsiao. Activated glucocorticoid signaling in pancreatitis contributes to acinar-to-ductal metaplasia and KrasG12D-driven tumorigenesis. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr B16. doi: 10.1158/1557-3125.RASONC14-B16
Abstract B49: Role of RAS palmitoyl-acyltransferase DHHC9 in hematopoiesis and NRAS leukemogenesis
Authors: Liu Ping , Jiao Bo , Linder Maurine , Ren Ruibao 
Published: May 2015

Abstract
Hyperactivation of RAS is common in human cancer, including hematological malignancies. Most oncogenic RAS proteins have been difficult to target. Identification of alternative targets that block RAS signaling is critical to develop therapies for RAS-related cancer. The biological activity of RAS proteins relies upon post-translational modifications (PTMs) that anchor RAS to cellular membranes. Protein palmitoylation regulates the membrane targeting, subcellular trafficking, and functions of proteins. We have previously examined the importance of PTMs in NRAS leukemogenesis and found for the first time that palmitoylation is essential for NRAS leukemogenesis. These studies suggest that targeting RAS palmitoylation may be an effective therapy for cancers involving RAS proteins that rely on palmitoylation for plasma membrane binding. In the previous studies, we blocked NRAS palmitoylation by mutating the palmitoylation site in NRAS. Therapeutic intervention of RAS palmitoylation requires targeting enzymes that mediate RAS palmitoylation. The reaction of protein S-palmitoylation is catalyzed by a family DHHC protein palmitoyl-acyltransferases (PATs). Thus far 24 mamalian PATs have been identified. It has been shown that DHHC9 (a 364-amino acid protein encoded by ZDHHC9, an X-linked gene), is the ortholog of yeast Ras2 PAT and constitute a mammalian PAT with specificity for H- and NRAS in vitro. Increased expression of DHHC9 has been found in various cancer. Here we investigate the role of DHHC9 in hematopoiesis and NRAS leukemogenesis in vivo. We found that ectopic expression of DHHC9 in mouse bone marrow cells hinders hematopoiesis, but is incapable of inducing hematological malignancies in mice. We also found that frequency of lineage-specific populations and hematopoietic stem cell phenotype were similar in mice with knockout alleles of ZDHHC9 as that of wild type mice, suggesting that DHHC9 is dispensable for normal hematopoiesis. Expression of oncogenic NRAS in bone marrow cells from ZDHHC9 knockout mice still induced leukemia but the mice survived longer that the wild type control mice. These results suggest that DHHC9 plays a role in the pathogenesis of NRAS-induced leukemia, but it is not the only PATs for RAS palmitoylation. We are identifying additional RAS PATs and developing cancer therapies targeting RAS palmitoylation.
Citation Format: Ping Liu, Bo Jiao, Maurine Linder, Ruibao Ren. Role of RAS palmitoyl-acyltransferase DHHC9 in hematopoiesis and NRAS leukemogenesis. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr B49. doi: 10.1158/1557-3125.RASONC14-B49