bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract PL04-04: Synthetic lethal approaches to targeting Ras mutant cancers.
Authors: Downward Julian
Published: August 2014

The RAS oncogenes are very frequently activated by mutation in human tumors, which very often show continued dependency on the signaling functions of RAS. In addition to controlling the RAF/MEK/ERK pathway, RAS proteins are established to be important direct regulators of type I phosphoinositide 3-kinases (PI3Ks), interacting via an amino terminal RAS binding domain (RBD). Disruption of PI3K p110alpha activation by oncogenic KRAS has been shown to prevent tumor development in a mouse model of lung cancer. Disruption of RAS-PI3K p110alpha interaction in established lung tumors prevents tumor progression and results in long-term stabilization of lung tumors. Coordinate inhibition of the MAPK pathway at the same time promotes tumor regression and dramatically reduces tumor burden. However, as yet it is unclear whether the combined targeting of pathways that RAS controls, such as RAF/ERK and PI 3-kinase/AKT, will prove effective in the treatment of RAS mutant cancers in the clinic, or whether this approach will prove unacceptably toxic. It is therefore important that other means of targeting this critical oncogene are considered. One such approach is the development of agents that directly inhibit the function of RAS proteins, for example by blocking interaction with effectors. Another approach, which will be explored here, is the identification of unique dependencies of RAS mutant tumor cells through the use of functional genomic screens. We have used RNA interference libraries on a panel of lung cancer cell lines to determine genes that are required for the survival of cells with oncogenic KRAS mutations, but not wild type KRAS. This has led to the identification of signaling networks that are essential for RAS mutant cells, including a transcriptional programme controlled by the GATA2 transcription factor. In mouse models of lung cancer, deletion of GATA2 leads to dramatic regression of RAS induced tumors. Although GATA2 itself is likely to be undruggable, investigation of the transcriptional targets of GATA2 has revealed three key pathways that are much more tractable: the proteasome, NF-kB and Rho signaling. Combined suppression of GATA2 regulated pathways with clinically approved inhibitors of the proteasome and Rho kinase causes marked tumor clearance. Discovery of the non-oncogene addiction of KRAS mutant lung cancers to GATA2 function presents a network of druggable pathways for therapeutic exploitation. We are currently testing combinations of GATA2 functional targeting with other approaches that show potential, such as MEK plus PI 3-kinase inhibition, and immune checkpoint modulators.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PL04-04.

Citation Format: Julian Downward. Synthetic lethal approaches to targeting Ras mutant cancers. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr PL04-04.
Abstract PL05-01: Heterogeneity in DCIS and invasive breast cancers.
Authors: Polyak Kornelia
Published: August 2014

Intratumor genetic and phenotypic heterogeneity of cancer cells underlies tumor progression and therapeutic resistance; thus, it is a major clinical problem. We have characterized intratumor genetic and phenotypic heterogeneity by immunoFISH (iFISH) in DCIS (ductal carcinoma in situ), primary invasive tumors, lymph node and distant metastases, as well as breast tumor biopsies before and after treatment. We found the highest genetic diversity in distant metastases but surprisingly these lesions were less divergent than primary-lymph node pairs. Intratumor diversity was also associated with tumor subtype and response to treatment. We also developed preclinical models to address the functional relevance of intratumor clonal heterogeneity in breast cancer and found cooperative interactions that promote tumor growth and metastatic progression. Our analyses of clonal frequency and drivers of tumor growth have revealed some unexpected findings. Our results emphasize the need to understand the cancer cell populations that compose tumors to be able to predict tumor evolution.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PL05-01.

Citation Format: Kornelia Polyak. Heterogeneity in DCIS and invasive breast cancers. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr PL05-01.
Abstract PL06-03: Detection of chromosomal alterations in the circulation of cancer patients with whole-genome sequencing.
Authors: Sausen Mark
Published: August 2014

Clinical management of cancer patients could be improved through the development of noninvasive approaches for the detection of incipient, residual, and recurrent tumors. We describe an approach to directly identify tumor-derived chromosomal alterations through analysis of circulating cell-free DNA from cancer patients. Whole-genome analyses of DNA from the plasma of colorectal and breast cancer patients and healthy individuals with massively parallel sequencing identified, in all patients, structural alterations that were not present in plasma DNA from healthy subjects. Detected alterations comprised chromosomal copy number changes and rearrangements, including amplification of cancer driver genes such as ERBB2, MET, and CDK6. The level of circulating tumor DNA in the cancer patients ranged from 1.4 to 47.9%. The sensitivity and specificity of this approach are dependent on the amount of sequence data obtained and are derived from the fact that most cancers harbor multiple chromosomal alterations, each of which is unlikely to be present in normal cells. Given that chromosomal abnormalities are present in nearly all human cancers, this approach represents a useful method for the noninvasive detection of human tumors that is not dependent on the availability of tumor biopsies.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PL06-03.

Citation Format: Mark Sausen. Detection of chromosomal alterations in the circulation of cancer patients with whole-genome sequencing. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr PL06-03.
Abstract PL08-03: Melanoma Research Alliance: Investing in innovation.
Authors: Perkins Louise M.
Published: August 2014

Melanoma is the deadliest of all skin cancers with more than 132,000 new cases each year worldwide and rising incidence. In the United States alone, melanoma incidence has tripled over the past three decades and it now represents the fifth most common cancer in men and the seventh most common in women. More than 76,690 new cases and more than 9,480 deaths are expected in the United States in 2013. Alarmingly, melanoma is the second most frequently diagnosed cancer among young adults in the U.S.

Historically, treatment options for patients with metastatic melanoma have been severely limited, but recent advances have considerably changed the landscape. In 2011, two new drugs were approved by the FDA for metastatic melanoma, ipilimumab and vemurafenib, providing the proof-of-concept for use of immunotherapy as well as targeted therapy in metastatic melanoma. Progress in treatment has continued with the 2013 approval of two additional drugs for patients with BRAF mutations, trametinib and dabrafenib. While these newly approved drugs alone will not cure most patients (although a small subset of patients have experienced longer term durable benefit from them), they establish the foundation for new, more successful approaches. Moreover, genomics studies have revealed a large number of drug targets for melanoma that offer significant opportunity to avert or treat drug resistant disease as well as for personalized medical approaches. As a result, there is unprecedented transformational progress on behalf of patients highlighted by the more than 100 new melanoma drugs in the pipeline, with nearly 300 clinical trials underway.

MRA-funded researchers are working to improve the success of the current therapies by identifying new biomarkers, combining treatments aimed at countering drug resistance, as well as discovering new and more effective drug targets for melanoma. By promoting collaboration in the field and providing critical investments in innovative translational research, MRA is at the forefront of these advances.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PL08-03.

Citation Format: Louise M. Perkins. Melanoma Research Alliance: Investing in innovation. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr PL08-03.
Abstract PR04: BRAF fusions define a distinct molecular subset of melanomas with potential sensitivity to MEK inhibition.
Authors: Hutchinson Katherine , Lipson Doron , Stephens Philip J. , Otto Geoff , Lyle Pamela L. , Vnencak-Jones Cindy L. , Ross Jeffrey S. , Sosman Jeffrey A. , Puzanov Igor , Miller Vincent A. , Pao William
Published: August 2014

Recurrent “driver” mutations at specific loci in BRAF, NRAS, KIT, GNAQ, and GNA11 define clinically-relevant molecular subsets of melanomas, but >30% are “pan-negative” for these recurrent mutations. Through next-generation sequencing (NGS), we identified a novel PAPSS1-BRAF fusion in a “pan-negative” melanoma. Characterization of oncogenic, transforming BRAF fusions have been described previously in cancer, but not yet in melanoma. Activation of the mitogen-activated protein kinase (MAPK) pathway in cells by ectopic expression of PAPSS1-BRAF can be abrogated by MEK inhibition but not by BRAF inhibition. Analysis of 51 additional melanomas revealed a second MEK inhibitor-sensitive BRAF fusion (TRIM24-BRAF), also in a “pan-negative” sample. Collectively, our data suggest that BRAF fusions define a new molecular subset of melanoma, comprising 8% of “pan-negative” cases, which may benefit from treatment with kinase inhibitors.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PR04.

Citation Format: Katherine Hutchinson, Doron Lipson, Philip J. Stephens, Geoff Otto, Pamela L. Lyle, Cindy L. Vnencak-Jones, Jeffrey S. Ross, Jeffrey A. Sosman, Igor Puzanov, Vincent A. Miller, William Pao. BRAF fusions define a distinct molecular subset of melanomas with potential sensitivity to MEK inhibition. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr PR04.
Abstract PR06: A functional screen of the epigenome identifies BRM/SMARCA2 as a critical synthetic lethal target in BRG1-deficient cancers.
Authors: Jagani Zainab , Hoffman Gregory , Rahal Rami , Buxton Frank , McAllister Gregory , Xiang Kay , Frias Elizabeth , Huber Janina , Lindeman Alicia , Chen Dongshu , Bagdasarian Linda , Romero Rodrigo , Ramadan Nadire , Phadke Tanushree , Haas Kristy , Jaskelioff Mariela , Wilson Boris , Meyer Matthew , McLaughlin Margaret E. , Roberts Charles WM , Myer Vic , Porter Jeff , Keen Nicholas , Mickanin Craig , Stegmeier Frank
Published: August 2014

Epigenetic dysregulation is an emerging hallmark of cancers, and the identification of recurrent somatic mutations in chromatin regulators implies a causal role for altered chromatin states in tumorigenesis. As the majority of epigenetic mutations are inactivating and thus do not present directly druggable targets, we reasoned that these mutations may alter the epigenomic state of cancer cells and thereby expose novel epigenetic vulnerabilities. To systematically search for epigenetic synthetic lethal interactions, we performed a deep coverage pooled shRNA screen across a large collection of cancer cell lines using a library targeting a diverse set of epigenetic regulators. Strikingly, this unbiased screen revealed that silencing of the SWI/SNF ATPase subunit BRM/SMARCA2, selectively inhibits the proliferation of BRG1-deficient cancer cells. The mammalian SWI/SNF complexes (mSWI/SNF) regulate chromatin structure through ATP-dependent nucleosome remodeling. Recent cancer genome studies have revealed a significant frequency of mutations in several components of the mSWI/SNF complexes including loss of the catalytic subunit BRG1 in non-small cell lung cancers. Our studies reveal that BRM knockdown selectively induced cell cycle arrest in BRG1-mutant cancer cells and significantly impaired the growth of BRG1-mutant lung tumor xenografts. BRM is the paralog of BRG1, suggesting a model in which mSWI/SNF mutations lead to a hypomorphic complex that promotes tumorigenesis but cannot tolerate complete inactivation. Therefore, our studies present BRM as an attractive therapeutic target in BRG1-mutant cancers.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PR06.

Citation Format: Zainab Jagani, Gregory Hoffman, Rami Rahal, Frank Buxton, Gregory McAllister, Kay Xiang, Elizabeth Frias, Janina Huber, Alicia Lindeman, Dongshu Chen, Linda Bagdasarian, Rodrigo Romero, Nadire Ramadan, Tanushree Phadke, Kristy Haas, Mariela Jaskelioff, Boris Wilson, Matthew Meyer, Margaret E. McLaughlin, Charles WM Roberts, Vic Myer, Jeff Porter, Nicholas Keen, Craig Mickanin, Frank Stegmeier. A functional screen of the epigenome identifies BRM/SMARCA2 as a critical synthetic lethal target in BRG1-deficient cancers. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr PR06.
Abstract 1760: Preclinical evaluation of IMGN853, an anti-FOLR1 antibody-maytansinoid conjugate, as a potential therapeutic for ovarian cancer
Authors: Whiteman Kathleen R. , Johnson Holly A. , Xu Shanqin , Carrigan Christina N. , Ab Olga , Pinkas Jan
Published: August 2014

IMGN853 (M9346A-sulfo-SPDB-DM4) is an antibody drug-conjugate consisting of the cytotoxic maytansinoid, DM4, covalently linked to the humanized monoclonal antibody M9346A, which selectively binds to folate receptor 1 (FOLR1). FOLR1 is over-expressed on ovarian cancers (38 of 67 tumor samples positive for FOLR1 ∼ 57%) suggesting that ovarian cancer may be a primary indication for clinical development of IMGN853.

FOLR1 expression was evaluated on a panel of ovarian cancer xenografts and human ovarian tumors using a calibrated immunohistochemical (IHC) staining method on formalin-fixed paraffin-embedded sections. The FOLR1 expression levels and patterns in three ovarian adenocarcinoma xenografts, OVCAR-3, IGROV-1 and OV-90, were consistent with those observed in FOLR1-positive patient ovarian tumor samples.

The anti-tumor activity of IMGN853 was evaluated in the three FOLR1-positive ovarian xenograft models identified. CB.17 SCID mice bearing established subcutaneous xenograft tumors (approximately 100 mm3) were treated with a single intravenous injection of IMGN853 at 1.2, 2.5 and 5.0 mg/kg (based on antibody concentration). IMGN853 was active in all three models evaluated. In OVCAR-3 xenografts, the minimally efficacious dose (MED) of IMGN853 was 1.2 mg/kg. The higher dose levels were highly active, resulting in complete regressions (CR) in 4/6 and 6/6 mice in the 2.5 and 5.0 mg/kg treatment groups, respectively. Treatment with IMGN853 resulted in strong anti-tumor activity in both IGROV-1 and OV-90 xenograft models, with a MED of 2.5 mg/kg, single injection.

The strong anti-tumor activity of IMGN853 against ovarian xenograft tumors with FOLR1 expression levels comparable to patient tumors suggests that IMGN853 may be a promising candidate for clinical development in ovarian cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1760. doi:10.1158/1538-7445.AM2011-1760
Abstract 2: IGF-1 attenuates antiestrogen- and antiprogestin-induced apoptosis in ER + breast cancer cells by MEK1 regulation of the BH3-only pro-apoptotic protein Bim
Authors: Takhar Suchreet , Periyasamy-Thandavan Sudharsan , Jackson William Hutch , Huang Shuang , Schoenlein Patricia
Published: August 2014

In an effort to understand the underlying mechanisms of inherent antiestrogen resistance in estrogen receptor positive (ER+) breast cancer cells, we have been studying the pro-survival role of insulin-like growth factor 1 (IGF-1) in protecting breast cancer cells from death induced by hormonal therapy. In past studies, we demonstrated that IGF-1, at physiologically relevant doses binds the insulin like growth factor receptor (IGF-IR), blocks antiestrogen- and antiprogestin- induced apoptosis in ER+ MCF-7 breast cancer cells. We further showed that the mechanism of protection was dependent on the action of the dual specificity protein kinase MEK1 (Abstract #4846, Proc Am Assoc Cancer Res, 51, 2010, p1178-79); however we did not elucidate the specific death effector pathway being blocked by MEK1/MAPK signaling. For this study, we sought to identify the specific death pathway blocked by the IGF-IR/MEK1/MAPK prosurvival signaling. We now present strong data identifying the pro-apoptotic BH3 family member Bim as a critical death effector activated by MEK1 blockade in ER+ breast cancer cells. We utilized Bim siRNA, which effectively down-regulated Bim intracellular protein expression by five-to ten-fold. Bim downregulation significantly attenuated the pro-apoptotic action(s) of U0126, as well as that of the antiestrogen 4-hydroxytamoxifen (4-OHT) and/or the antiprogestin mifepristone (MIF). Bim knockdown reduced the generation of ROS that results from treatment with 4-OHT, MIF, and U0126 (whether used as monotherapies or in combination) and is required for MCF-7 apoptotic cell death under these treatment conditions. We are currently elucidating how Bim action induces cell death in breast cancer cells with compromised MEK1 action. These studies support the targeting of MEK1 to activate a Bim-dependent apoptotic pathway during hormonal therapy of early-stage breast cancer, particularly in patients with high circulating levels of IGF-1.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2. doi:10.1158/1538-7445.AM2011-2
Abstract 4139: Diagnostic performance of the F-18 labeled bombesin analog BAY 86-4367 in patients with primary prostate cancer
Authors: Schäfer Niklaus , Valencia Ray , Borkowski Sandra , Geissler Eva , Kristiansen Glen , Rohde Beate , Bacher-Stier Claudia , Krause Bernd J. , Hany Thomas F.
Published: August 2014

Purpose: BAY 86-4367 is a new directly F-18 labeled, synthetic bombesin analog (3-Cyano-4-[18F]fluorobenzoyl-Ala(SO3H)-Ala(SO3H)-Ava-Gln-Trp-Ala-Val-NMeGly-His-Sta-Leu-NH2) with antagonistic properties, targeting Gastrin-releasing-peptide receptors (GRPr). The aim of this proof of mechanism (PoM) study is to demonstrate the feasibility, safety, tolerability, biodistribution and diagnostic performance of the PET tracer BAY 86-4367 in patients with primary prostate cancer.

Methods: 5 patients with non-treated primary prostate cancer (PSA range 7 to 24 µg/l) were prospectively included in the study. All patients had standardized biopsy proven primary prostate cancer with Gleason scores ranging from 6 (3+3) to 9 (4+5). All patients had standardized sequential dynamic and static PET/CT using the F-18 labeled tracer BAY 86-4367 for primary staging. Safety data (vital signs, ECG, adverse effects) were assessed in all patients. Four patients had a prior PET/CT scan with F-18 choline. Patients were scheduled for prostatectomy of primary prostate cancer. Full prostate samples were histopathologically analyzed to further confirm the imaging localisation data.

Results: The tracer BAY 86-4367 was well tolerated after injection of ∼300 MBq and a peptide mass dose <40 µg per patient. Safety data showed no relevant changes in the sequential blood values, electrocardiograms, urine testing or physical examination. Malignant lesions were depicted in 3/5 patients with the F-18 labeled BAY 86-4367 tracer. Biopsy verified the correct tumor localisation of these imaging findings. In two patients with histologically proven primary prostate cancer, BAY 86-4367 showed no active accumulation in the prostate. F-18 choline PET/CT was performed in 4/5 patients with positive signals in all 4 patients. Correlation with biopsy showed correct localisation of F-18 choline in tumor tissue. However, there was false positive F-18 choline accumulation in benign hyperplasia of the prostate.

Conclusion: PET imaging with the F-18 labeled bombesin analog BAY 86-4367 is safe. The tracer BAY 86-4367 correctly depicts primary prostate cancer in a subset of patients. However, diagnostic accuracy of bombesin analogs in GRPr imaging needs to be further explored.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4139. doi:10.1158/1538-7445.AM2011-4139
Abstract LB-294: GBR 500, a monoclonal VLA-2 antibody inhibits tumor and metastasis growth but not extravasation in a prostate cancer animal model
Authors: Attinger Antoine , Hou Sam , Pesenti Enrico A. , Mancini Laura , Mottl Harald
Published: August 2014

VLA-2 is the alpha2beta1 integrin which mediates interactions of cells with collagens, laminin and other extracellular matrix components. In tumor cells, VLA-2 plays a role in neovascularization, tumor-stroma interactions and metastasis.

The objective of this study was to understand the role of VLA-2 in extravasation and metastasis of prostate cancer cells. VLA-2 may play a role by mediating extravasation through the basement membrane or in supporting metastasis growth in the stroma through interactions with the extracellular matrix.

We assessed whether GBR 500, a monoclonal IgG4 antibody directed against the alpha2 subunit of the alpha2beta1 integrin heterodimer could prevent extravasation and metastasis formation. GBR 500 is currently undergoing clinical phase I studies. The antibody binds to human but not to mouse VLA-2.

In an orthotopic mouse Xenograft model using a DU145-luc cell line we explored the importance of VLA-2 for tumor growth by inhibition of VLA-2 with a combination of GBR 500, specific for human VLA-2 and HA1–29, specific for mouse VLA-2. Bevacizumab was used as positive control.

In vitro, GBR 500 inhibits the binding of PC3 prostate cancer cells to collagen with an EC50 of 0.035 μg/ml. To study the impact of VLA-2 on extravasation in a PC3-luc metastasis model we blocked VLA-2 with GBR 500 before injection of tumor cells and by pre-dosing mice with a 50 mg/kg dose i.v.

This group of mice was compared with two groups of mice which where treated i.p with GBR 500 twice a week at 1mg/kg and 5 mg/kg. The positive control was bevacizumab at 5mg/kg.

Results: Bi-weekly treatment with GBR 500 5 mg/kg successfully slowed tumor growth and was as effective as bevacizumab 5 mg/kg treatment. Pre-incubation and pre-dosing with VLA-2 did not affect the extravasation and metastases formation.

Conclusion: : Inhibition of tumor growth was exhibited by VLA-2 in a prostate cancer PC3-luc metastasis model. This inhibition has no apparent effect on the extravasation of PC3 cells indicating that the antibody acts in the tissue by preventing establishment of metastases. The potency of GBR 500 in this model is comparable to bevacizumab.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-294. doi:10.1158/1538-7445.AM2011-LB-294
Abstract LB-356: An siRNA screen identifies Rsk1 as a key modulator of lung cancer metastasis
Authors: Lara Romain , Mauri Francesco A. , Taylor Harriet , Derua Rita , Shia Alice , Gray Colin , Nicols Alastair , Shiner Robert J. , Schofield Edward , Bates Paul A. , Waelkens Etienne , Dallman Maggie , Lamb Jonathan , Zicha Daniel , Downward Julian , Seckl Michael J. , Pardo Olivier E.
Published: August 2014

Lung cancer is the commonest cancer killer worldwide. The appearance of distant metastasis is one of the main reasons for failing to cure patients with this disease. To address the underlying molecular mechanisms that regulate cancer cell motility, we performed an automated kinome-based RNA interference screen in the non-small cell lung cancer (NSCLC) cell line A549. We studied changes in cell migration patterns using timelapse microscopy and automatic tracking. Mathematical analysis of the obtained cell tracks provided information on migration speed and distance. 48 kinases were identified that were previously unknown to regulate cell motility. Among our candidates, were several members of the ribosomal S6 kinase (Rsk) family. In particular, Rsk1 silencing increased, while Rsk2 and 4 downregulation decreased, cell motility. These effects correlated with changes to the actin cytoskeleton as well as decreased E-cadherin and increased Vimentin expression levels. A secondary 3-dimensional invasion screen for our candidates confirmed that Rsk1 downregulation increased the invasiveness of A549 cells. In silico analysis and biochemical experimentation revealed that Rsk1 interacted with the actin regulators Vasp and Mena. This correlated with the ability of Rsk1 to phosphorylate Vasp on Thr-278, a site regulating Vasp-mediated actin dynamics. Moreover, Rsk1 silencing enhanced the metastatic behaviour of A549 cells in vivo using a zebrafish xenograft model. Importantly, immunohistochemical staining validated Rsk1 down regulation in metastatic lung cancer samples compared to isogenically matched primary tumours. Moreover, patients with Rsk1-negative lung primary tumours showed an increased number of metastatic lesions as well as an increase in Rsk2 and/or Rsk4 staining establishing Rsk family members as strong determinants of lung cancer cell metastasis and potential predictive markers for the progression of this disease.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-356. doi:10.1158/1538-7445.AM2011-LB-356
Abstract 1000: ATP7A mutation reduces resistance to chemotherapy agents in vitro and in vivo.
Authors: Zhu Sha , Petris Michael J.
Published: August 2014

The Menkes protein (ATP7A), a copper-translocating P-type ATPase, is responsible for the loading of copper from the cytosol into secretory compartments of the cell for incorporation into newly synthesized copper-requiring enzymes. Previous studies using cultured cell lines have suggest that ATP7A is able to modulate cellular accumulation of cisplatin, a platinum-containing chemotherapy agent. In this study, we generate isogenic ATP7A-WT and ATP7A-knockout mouse embryonic fibroblast cells line pairs. We demonstrate that ATP7A deletion significantly decreases cellular resistance to cell cycle non-specific platinum agents, cisplatin & carboplatin and cell cycle specific alkaloid agent, vincristine sulfate. In addition, loss of ATP7A sensitizes xenograft tumor growth to cisplatin toxicity. These findings identify the ATP7A copper transporter as an active participant in multidrug resistance pathways in vivo, underscoring this transporter as a potential drug target to augment platinum-based chemotherapeutics.

Citation Format: Sha Zhu, Michael J. Petris. ATP7A mutation reduces resistance to chemotherapy agents in vitro and in vivo. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1000. doi:10.1158/1538-7445.AM2013-1000
Abstract 1001: Elevated fibroblast growth factor-inducible 14 (Fn14): a novel therapeutic target in gastric cancer.
Authors: Kim Seon-Young , Kwon Oh-Hyung , Kim Yong Sung , Noh Seung-Moo , Song Kyung-Sang
Published: August 2014

Chemoresistance is one of the most serious problems in the cancer treatment. Here we show that Fn14 is a gene that promotes resistance to 5-fluorouracil (5-FU) in gastric cancer. We found that 5-FU treatment augmented Fn14 expression at both the RNA and protein level in gastric cancer cell lines, and that knock-down of Fn14 using shRNA accelerated sensitivity to 5-FU. We then investigated the underlying mechanism of Fn14-mediated chemoresistance. 5-FU treatment resulted in up-regulation of Fn14 expression as well as Bcl-xL by translocation of NF-κB to the nucleus and subsequent transcriptional activation. To examine whether NF-κB binds directly to Fn14 promoter, we performed luciferase assay. As a result, 5-FU treatment augmented Fn14 promoter activity, while increased activity of Fn14 reporter gene was reduced by NF-κB inhibitor and NF-κB knock-down by siRNA. In chromatin immunoprecipitation assay, we revealed that 5-FU treatment enhanced NF-κB binding to Fn14 promoter, indicating that NF-κB activation by 5-FU was the principal event for Fn14 up-regulation followed by resistance to 5-FU in gastric cancer. Our results suggest that Fn14 is a novel therapeutic target, and that dysfunction of Fn14 combined with 5-FU treatment is an effective therapeutic strategy to overcome resistance to 5-FU of gastric cancer patients.

Citation Format: Seon-Young Kim, Oh-Hyung Kwon, Yong Sung Kim, Seung-Moo Noh, Kyung-Sang Song. Elevated fibroblast growth factor-inducible 14 (Fn14): a novel therapeutic target in gastric cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1001. doi:10.1158/1538-7445.AM2013-1001
Abstract 1002: Deletion of GCN5 confers sensitivity to the histone deacetylase inhibitor CG-1521.
Authors: Gaupel Ann-Christin , Begley Thomas J. , Tenniswood Martin P.
Published: August 2014

Aberrant histone post-translational modifications including acetylation are common in human cancers and result in dysregulation of gene expression. Histone acetylation is regulated by histone acetyltransferases (HATs) and histone deacetylases (HDACs) and HDAC inhibitors (HDACi) are promising anticancer therapeutics. Our laboratory has focused on studying the effects of hydroxamic acid based HDACis including TSA, SAHA and CG-1521. We have previously shown that CG-1521 induces cell cycle arrest and apoptosis in various cell lines of breast and prostate cancer.

The purpose of this study is to gain insight into the mechanism of the HDAC inhibitor CG-1521 and identify potential combinatorial drug targets. We have employed a whole genome yeast deletion library screen to determine which gene deletions confer sensitivity and resistance to CG-1521. 407 sensitive and 80 resistant strains were identified. We used gene ontology enrichment analysis to determine which pathways are modulated by CG-1521. Sensitive strains are highly enriched in processes regulating chromatin remodeling and transcription. The list of resistant strains contains many genes involved in the regulation of transcription and tRNA modification. Deletions of components of the SAGA HAT complex are highly overrepresented in the sensitive strains, including the catalytic subunit Gcn5. It appears that the SAGA complex is required to reduce the effect of CG-1521 on cell growth. Cell cycle analysis shows that CG-1521 treatment in Saccharomyces cerevisiae results in G1 arrest in both the wild type and the gcn5Δ strain. The gcn5Δ strain displays increased sensitivity to CG-1521 induced cell death compared to the wild type strain. In contrast to the highly sensitive gcn5 deletion strain, a yeast strain expressing a catalytically inactive variant of the Gcn5 protein is less sensitive to CG-1521. This indicates that functions other than the acetyltransferase activity are partially sufficient to attenuate the effects of CG-1521.

We have identified that disruption of the SAGA HAT complex can sensitize cells to CG-1521 and are validating whether loss of the human Gcn5 homologs, Gcn5 and PCAF, also confers sensitivity to CG-1521 in breast cancer cell lines. Taken together, our work suggests that the combination of selective HAT and HDAC inhibitors might be effective for the treatment of cancer.

Citation Format: Ann-Christin Gaupel, Thomas J. Begley, Martin P. Tenniswood. Deletion of GCN5 confers sensitivity to the histone deacetylase inhibitor CG-1521. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1002. doi:10.1158/1538-7445.AM2013-1002
Abstract 100A: Prognostic significance of the expression levels of target genes of retinoic acid in hepatocellular carcinoma.
Authors: Shiota Goshi , Kanki Keita
Published: August 2014

Hepatocellular carcinoma (HCC), a common and fatal malignancy, is increasing in incidence in developed countries. HCC generally arises in cirrhotic livers and has a poor prognosis because of the high incidence of disease recurrence after curative treatment. To improve patient prognosis, identification of new targets for early detection, chemoprevention, and treatment is urgently required.

In the pathogenesis of chronic liver disease, activation of hepatic stellate cells accompanied by decreasing vitamin A storage has been observed, leading to development of the hypothesis that the loss of retinoid content is closely associated with the progression of chronic liver diseases including HCC. In a previous study, we observed steatohepatitis and HCC development in transgenic mice that express a dominant-negative form of RAR in a liver-specific manner. These findings indicate that identifying genes regulated by retinoid signaling is important for understanding the molecular mechanisms of liver disease leading to hepatocarcinogenesis.

To identify novel retinoic acid (RA)-responsive genes facilitating the antitumor activity of RA in hepatocellular carcinoma (HCC), we performed a gene screening based on in silico analysis of retinoic acid response elements (RAREs), chromatin immunoprecipitation analysis of the retinoic acid receptor (RAR), and gene expression analysis. We identified 201 candidate genes with promoter regions containing consensus RAREs using in silico analysis. We identified 126 candidate genes with functional RAREs which are occupied by RAR and finally selected 26 RA-responsive genes in 2 human HCC and 1 human breast cancer cell lines. Among these genes, we identified OTU domain-containing 7B (OTUD7B) and frizzled family receptor 4 (FZD4) as potential inducers of RA-mediated antitumor activity. OTUD7B and FZD4 were involved in the regulation of nuclear factor κB and Wnt/β-catenin signaling, respectively, and affected the viability of HCC cell lines. To evaluate the clinical significance of RA-responsive genes in HCC, gene expression analysis was performed using tumor and nontumor tissues from 171 patients. In univariate and multivariate analyses, low OTUD7B mRNA expression in tumor tissue was associated with a poor prognosis forHCC patients. Conclusion: We identified RA-responsive genes that exhibit antitumor activity against HCC cells. These findings provide useful information to understand the molecular mechanisms underlying the chemopreventive effects of RA against liver diseases, including HCC.

Citation Format: Goshi Shiota, Keita Kanki. Prognostic significance of the expression levels of target genes of retinoic acid in hepatocellular carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 100A. doi:10.1158/1538-7445.AM2013-100A
Abstract 1010: New thiol-ω(γ-lactam amide) SAHA analogues as potent histone deacetylase (HDAC) inhibitors..
Authors: Giannini Giuseppe , Battistuzzi Gianfranco , Vignola Davide , Vesci Loredana , Milazzo Ferdinando Maria , Guglielmi Mario Berardino , Barbarino Marcella , Pisano Claudio , Cabri Walter
Published: August 2014

Histone deacetylase inhibitors (HDACi) are one of the last frontiers in pharmaceutical research. Two HDACi are already part of armamentarium of the anticancer drugs of the oncologists: Vorinostat, Zolinza® (SAHA) and Romidepsin, Istodax® (depsipeptide; FK-228), both licensed by the FDA for the treatment of cutaneous T-cell lymphoma (CTCL). Beyond them, more than twenty new drugs are currently under pre-clinical and clinical investigation as single agent and in combination therapies against different cancers and in other several novel therapeutic indications. Mainly they are hydroxamic acids and benzamide derivatives; however none has emerged superior to SAHA in terms of potency.

In our search, we have selected a new generation of HDACi: thiol-based SAHA bearing a lactam amide in ω-position. This new generation was highly competitive compared to competing drugs, displaying sub-micromolar to low nanomolar inhibitor activity on HDACs, being especially powerful on HDAC6 isoform. They exhibited higher anti-proliferative activity than SAHA on different human cell lines. In vivo they were orally administered and showed a higher potency than SAHA, with a negligible toxicity.

The overall profile of this new class of HDAC inhibitors, including synthesis and a comprehensive pharmacological characterization, will be presented.

These encouraging results prompted us to select a drug candidate which is currently in a phase of pre-clinical evaluation.

Citation Format: Giuseppe Giannini, Gianfranco Battistuzzi, Davide Vignola, Loredana Vesci, Ferdinando Maria Milazzo, Mario Berardino Guglielmi, Marcella Barbarino, Claudio Pisano, Walter Cabri. New thiol-ω(γ-lactam amide) SAHA analogues as potent histone deacetylase (HDAC) inhibitors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1010. doi:10.1158/1538-7445.AM2013-1010
Abstract 1018: Inhibition of BET bromodomain targets genetically diverse glioblastoma.
Authors: Wang Jialiang , Cheng Zhixiang
Published: August 2014

Epigenetic regulations have been increasingly recognized as an integral part of tumor biology and attractive therapeutic targets. The bromodomain and extra-terminal domain (BET) proteins specifically recognize acetylated lysine residues on histone tails. BET bromodomain inhibition with a first-in-class inhibitor JQ1 reduces expression of a broad spectrum of growth promoting and antiapoptotic genes, including c-Myc, resulting in suppression of several hematopoietic cancers and NUT midline carcinoma. We and other groups have previously reported the critical role of c-Myc in glioblastoma stem cells. Here, we demonstrated broad antineoplastic effects of JQ1 both in ex vivo cultures and orthotopic models using a panel of glioblastoma tumors carrying different genetic lesions. JQ1 induced marked cell cycle arrest and apoptosis in association with p21WIP1/CIP1 induction and hTERT, Bcl-2 and Bcl-xL reduction. Consistent with previous studies, JQ1 decreased c-Myc expression in glioblastoma. However, exogenous c-Myc did not significantly protect glioblastoma from JQ1, unlike the observations in hematopoietic cancers. Cells genetically engineered for Akt hyperactivation or p53/Rb inactivation did not compromise JQ1 efficacy, suggesting that these signaling pathways commonly altered in glioblastoma may not confer resistance to JQ1. Taken together, our results suggest potentially broad therapeutic utility of BET bromodomain inhibition for treating genetically diverse glioblastoma tumors.

Citation Format: Jialiang Wang, Zhixiang Cheng. Inhibition of BET bromodomain targets genetically diverse glioblastoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1018. doi:10.1158/1538-7445.AM2013-1018
Abstract 1022: Carfilzomib demonstrates broad antitumor activity in preclinical lung cancer models.
Authors: Baker Amanda F. , Sands Barbara , Carbajal Lilliana , Anderl Janet , Chan Elena T. , Kirk Christopher J. , Garland Linda L.
Published: August 2014

Carfilzomib (CFZ), is an irreversible inhibitor of the chymotrypsin-like activity of the proteasome that was recently FDA approved for treatment of refractory and relapsed multiple myeloma. Early Phase 1B studies of CFZ showed signs of clinical activity in a number of solid tumors, including non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). We investigated the anti-tumor activity of CFZ monotherapy and in combination with cisplatin in NSCLC and SCLC cell lines and xenograft models. CFZ showed marked anti-proliferative activity in A549, H1993, H520, H460, H1299 NSCLC cell lines, with IC50 values after 96 hours of treatment ranging from 1.0 nM to 27 nM. CFZ + cisplatin resulted in antagonistic anti-proliferative activity in the NSCLC A549, H1993, and H520 cells, independent of sequence of drug administration. In vivo, CFZ monotherapy resulted in tumor growth inhibition in an A549 NSCLC murine xenograft model. In contrast, the SCLC cell lines SHP77 and H69 were more resistant to the anti-proliferative effects of CFZ, with IC50 values at 96 hours of 0.917 μM and >30 μM, respectively. In vitro, in the SHP-77 SCLC cell line CFZ + Cisplatin showed synergistic activity. In vivo, in a SHP-77 SCLC SCID murine xenograft model CFZ monotherapy resulted in an 8-day tumor growth delay to reach 1500 mm3. No additive or synergistic anti-tumor efficacy was observed for CFZ + cisplatin in this model. Western blot analysis from SHP-77 cell lines grown in vitro and treated with CFZ showed an increase in cleaved PARP and p53, supporting activation of apoptosis. We will report on inhibition of the chymotrypsin-like proteasome activity in CFZ-treated lung cancer cell lines. Together, these pre-clinical studies support further preclinical and clinical investigations of CFZ in NSCLC and SCLC, including novel CFZ + anti-cancer drug combinations.

Citation Format: Amanda F. Baker, Barbara Sands, Lilliana Carbajal, Janet Anderl, Elena T. Chan, Christopher J. Kirk, Linda L. Garland. Carfilzomib demonstrates broad antitumor activity in preclinical lung cancer models. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1022. doi:10.1158/1538-7445.AM2013-1022
Abstract 1024: Therapeutic efficacy of RNA interference targeting focal adhesion kinase against orthotropic xenograft of human malignant pleural mesothelioma in SCID mice.
Authors: Huang Jun , Liu Dai-Shun , Kakiuchi Soji , Goto Hisatsugu , Hanibuchi Masaki , Nishioka Yasuhiko
Published: August 2014

Malignant pleural mesothelioma (MPM) is an aggressive neop lasm of the pleura. The prognosis for MPM remains disappointing, although there have been some improvements in prognosis from newer chemotherapies and multimodality treatments. Focal adhesion kinase (FAK) is an important regulator of cellular signaling, migration, apoptosis, and cell cycle progression. We tested the hypothesis that FAK plays an important role in the pathogenesis of MPM and examined the effect of inhibiting FAK expression of MPM using small interfering RNA (siRNA) in vitro and in vivo. FAK expression was evaluated by Western and Northern blots. Knockdown of FAK resulted in detachment and proliferation inhibition of MPM cells in vitro. We assessed the therapeutic applicability of FAK siRNA in orthotopic xenograft model in SCID mice. FAK siRNA treatment inhibited the growth of MPM tumors and production of pleural effusion. These findings suggest that FAK may be a potential therapeutic target for human MPM and exogenous delivery of siRNA targeting FAK may be a useful strategy for MPM therapy.

Citation Format: Jun Huang, Dai-Shun Liu, Soji Kakiuchi, Hisatsugu Goto, Masaki Hanibuchi, Yasuhiko Nishioka. Therapeutic efficacy of RNA interference targeting focal adhesion kinase against orthotropic xenograft of human malignant pleural mesothelioma in SCID mice. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1024. doi:10.1158/1538-7445.AM2013-1024
Abstract 1028: Role of Hsp90 in the stability of EGFR from radiation and cisplatin-induced degradation.
Authors: Elaimy Ameer L. , Ahsan Aarif , Ray Dipankar , Lawrence Theodore S. , Nyati Mukesh K.
Published: August 2014

Heat-shock protein 90 (Hsp90) is an evolutionary conserved eukaryotic molecular chaperone that has a large number of clients including signaling molecules such as EGFR. Induction of Hsp90 upon cellular stress induced by radiation or chemotherapy can enhance stabilization of its clients which may lead to resistance to therapy and can often provide an environment for metastasis. Therefore, targeting Hsp90 has been shown to be a potential therapeutic approach to induce EGFR degradation and block metastatic spread. The aim of this study is to further understand the mechanism of Hsp90 induction and its post-translational modifications within cancer cells as well as its microenvironment and their significance in EGFR protein stability. We hypothesized that activation of Hsp90 upon cellular stress induced by radiation and chemotherapy provides stability to EGFR not only in cancer cells, but also in tumor-associated endothelial cells, which allows cancer cell survival and metastatic spread by increasing EGFR (and other clients) stability. Our preliminary data indicate that an enhancement in EGFR protein interaction with Hsp90 in both endothelial cells and head and neck cancer cell lines correlate with cell survival upon radiation or cisplatin treatment. Cisplatin treatment also caused an increase in Hsp90 activation as reflected by an increase in ATP binding activity. Increase in EGFR phosphorylation led to a decrease in its interaction with Hsp90. We also found that inhibition of Hsp90 activity reduced this interaction, which decreased EGFR half-life and promoted cell-death in cancer and endothelial cells. We are now extending our research efforts to understand the effects of radiation and cisplatin on the post-translational modifications of Hsp90 such as phosphorylation and its potential role in binding with EGFR. The long-term goal of this study is to develop a specific protein-protein interaction antagonist (PPI) to induce selective EGFR degradation and block the survival and metastatic spread regulated by EGFR.

Citation Format: Ameer L. Elaimy, Aarif Ahsan, Dipankar Ray, Theodore S. Lawrence, Mukesh K. Nyati. Role of Hsp90 in the stability of EGFR from radiation and cisplatin-induced degradation. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1028. doi:10.1158/1538-7445.AM2013-1028