bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract B22: Dynamics of cancer cell survival dependency on Bcl-2 family members
Authors: Mc Henry Kevin T. , Donovan Jerry , Loo Alice , Fisher David E. , Zawel Leigh , Porter Dale 
Published: June 2012

Abstract
Apoptosis is regulated through the interactions of the Bcl-2 family of proteins. Overexpression of anti-apoptotic Bcl-2 family members plays a key role in promoting survival for cells undergoing various insults that would normally trigger cell death. Consequently, these proteins are believed to serve as contributing factors to the processes of tumor initiation, tumor progression and the development of resistance to therapeutics. ABT-263, an antagonist of Bcl-2, Bcl-xL, and Bcl-w, is currently being tested in clinical trials. Some cancer cells express high amounts of Mcl-1, another Bcl-2 family anti-apoptotic protein that shares pro-survival function with Bcl-2 but is not targeted by ABT-263. Preclinical data indicates Mcl-1 overexpressing cells are not sensitive to ABT-263. To understand this mechanism of Mcl-1 dependence, A2058 melanoma cells were infected with a lentivirus encoding inducible shRNA against Mcl-1. Upon induction of MCL1 knockdown, massive cell death occurred. Interestingly, a small subset of the cell population managed to survive. Subsequent western blot analysis confirmed a sustained depletion of Mcl-1. Further study indicated A2058 cells deficient in Mcl-1 survived by upregulating expression of Bcl-2, a process we term “switching dependency”. In addition, these cells became sensitized to ABT-263 treatment. An A2058 xenograft model indicates that combined knockdown of both Mcl-1 and Bcl-2 significantly inhibited tumor growth when compared to tumors treated with ABT-263 lacking either protein individually. Real-time kinetic studies reveal a rapid sensitization of A2058 cells to ABT-263 upon sh-RNA induction. To understand whether de novo protein synthesis of Bcl-2 plays a mechanistic role in dependency switching, A2058 sh-Mcl-1 cells were treated with the protein synthesis inhibitor cycloheximide. Kinetic analysis indicates that de novo protein synthesis is not required for dependency switching. Real-time quantitative PCR was then employed to determine if a relationship exists between the decrease in Mcl-1 mRNA, and subsequent sensitivity to ABT-263, is a consequence of a change in Bcl-2 mRNA levels. Surprisingly, the results indicate as the loss of Mcl-1 message occurs, there is no concurrent change in Bcl-2 mRNA. Taken together these data indicate that dependency switching, and therefore survival, occurs without de novo Bcl-2 protein synthesis or alterations in protein turnover. Furthermore, dependency switching is a possible mechanism cancer cells employ to develop resistance toward various anti-cancer therapies with novel implications for both the concept of oncogene addiction and development of targeted cancer therapeutics. Therefore there is an immediate need for elucidation of this novel cancer resistance mechanism.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B22.
Abstract B220: Identification and characterization of kinase targets to treat melanoma
Authors: Madhunapantula SubbaRao V. , Sharma Arati , Chandagalu Raghavendra Gowda D. , Robertson Gavin P. 
Published: June 2012

Abstract
Incidence and mortality rates for malignant melanoma continue to rise every year. Lack of functional knowledge regarding key proteins regulating melanoma development is one of the major drawbacks hindering development of targeted therapeutics. Additionally, it has been found that monotherapies targeting proteins regulating melanoma development are not as effective as combination therapies warranting research to identify new therapeutic targets that can be inhibited in combination to better treat melanoma. Therefore, we conducted a siRNA-based screen to functionally identify key kinases regulating melanoma development using the Amaxa 96-well shuttle system and a Stealth siRNA library consisting of siRNAs targeting 636 human kinases. Involvement of the identified kinases is validated in vitro using multiple metastatic melanoma cell lines and in vivo in xenografted tumor kinetics studies. The screen identified a number of known and novel kinase targets. Results of primary and secondary screens, validation of the identified targets in vitro and in vivo are presented. Since the data demonstrated in this screen encompasses all the known kinases, it helps to functionally identify key kinases involved in melanoma as well as, design and select appropriate chemotherapeutic agents or agent combinations to effectively inhibit melanoma tumor development. In conclusion the data obtained in this siRNA screen contributes significantly to the currently available knowledge by demonstrating key kinases to inhibit melanoma tumor development either singly or in combination.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B220.
Abstract B224: Multi-tyrosine kinase targeting resulting in concomitant downregulation of proliferation/survival pathways dependent on FGF-R3, Jak2 and BCMA in human multiple myeloma cells
Authors: Cassinelli Giuliana , Ronchetti Domenica , Laccabue Diletta , Mattioli Michela , Cuccuru Giuditta , Favini Enrica , Nicolini Valentina , Greco Angela , Neri Antonino , Zunino Franco , Lanzi Cinzia 
Published: June 2012

Abstract
Proliferation/survival pathways constitutively activated by genetic alterations in multiple myeloma (MM), or sustained by the bone marrow (BM) microenvironment, provide opportunities for the development of novel targeted therapies. Deregulated protein tyrosine kinases (TKs) involved in these pathways may play a critical role in driving the MM malignant phenotype thus representing attractive therapeutic targets. We have investigated the effects of a multi-target tyrosine kinase inhibitor (1,3-dihydro-5,6-dimethoxy-3-[(4-hydrophenyl)methylene]1-indol-2-one) (named RPI-1 in our laboratory) in a panel of human MM cell lines, including t(4;14) positive cell lines expressing the TK receptor FGF-R3. Cells harboring FGF-R3 activating mutations (KMS11 and OPM2) displayed the highest sensitivity to the drug antiproliferative effect. However, proliferation induced by the FGF-R3 ligand, aFGF, was abrogated even in cells harboring a non-constitutively active receptor. Drug treatment inhibited activation and expression of the FGF-R3Y373C mutant as well as aFGF-dependent signaling involving AKT and ERKs. Jak2 has been identified as an additional target of RPI-1 in MM cells. Inhibition of Jak2 TK resulted in STAT3 inactivation. Blockade of these proliferation/survival pathways was associated with activation of caspase-dependent apoptosis. Moreover, the TK inhibitor abrogated proliferative and pro-invasive stimuli provided by conditioned medium from mesenchymal stromal cells. Gene expression analysis of KMS11 cells showed 22 upregulated and 52 downregulated genes upon RPI-1 treatment, with an early modulation of genes implicated in MM pathobiology such as SAT-1, MYC, MIP-1α/β, FGF-R3, and the growth factor receptor B-cell maturation antigen (BCMA). Thus, concomitant blockade of FGF-R3 and Jak2 results in inhibition of several MM-promoting pathways, including BCMA-regulated signaling, and downregulation of disease-associated proteins. Overall, these data support the therapeutic interest for FGF-R3/JAK2 multi-target approaches in the treatment of t(4;14) MM.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B224.
Abstract B231: Targeting Her2+ ductal breast cancer with PDL192, a novel humanized anti-TweakR monoclonal antibody
Authors: Chao Debra T. , Su Mien , Sho Mien , Choi Doghee , Ye Shiming , Tomlinco Sonia , Kim Han , Zhang Yongke , Yin Johnny , Hsi Eric D. , Durkan Lisa , Lambert Peter , Starling Gary C. , Afar Daniel E.H. , Culp Patricia A. 
Published: June 2012

Abstract
TWEAK receptor (TweakR), also known as Fn14, is a cell surface protein and member of the tumor necrosis factor receptor superfamily. TNFRSF family members are appealing therapeutic targets due to their expression and function in tumor cells. The goal of the current study was to examine the potential of TweakR as a therapeutic target in various subtypes of breast cancer by 1) determining expression of TweakR using immunohistochemistry (IHC) and 2) treating cells derived from breast cancer in vitro and in vivo with PDL192, a novel, humanized anti-TweakR mAb. Overexpression of TweakR protein in breast cancer was confirmed by IHC on formalin fixed paraffin embedded (FFPE) tissues. TweakR was elevated in infiltrating tumors when compared with normal adjacent tissues. 30 to 40% of various subtypes of invasive ductal breast cancer samples stained highly for TweakR; however, fewer than 5% of lobular breast cancer samples had high levels of TweakR. In addition, a strong positive correlation of TweakR and Her2 expression was observed, irrespective of ER status. More than 60% of Her2+ invasive ductal cancer exhibited elevated levels of TweakR. Strong TweakR expression was also observed in bone metastasis samples from primary breast cancer but rarely in benign tumors, such as DCIS.
PDL192 inhibited the in vitro growth of various subtypes of TweakR-expressing breast cancer cell lines and this activity was augmented by crosslinking the mAb. In addition, PDL192 significantly inhibited the in vivo growth of a variant of the breast cancer xenograft model MDA-MB231 that exhibits metastatic potential. PDL192 administration exhibited a dose-dependent inhibition of primary tumor growth and lung metastasis and enhanced the anti-tumor activity of several chemotherapy agents currently used to treat breast cancer. These data provide the rationale to evaluate PDL192 as a potential therapy for the treatment of breast cancer. Currently, PDL192 is being tested in a phase I safety study for the treatment of patients with solid tumors.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B231.
Abstract B239: Profiling the type I insulin-like growth factor receptor (IGF1R) pathway regulated metastasis signature
Authors: Sarver Aaron , Sachdev Deepali 
Published: June 2012

Abstract
The insulin-like growth factors (IGFs) acting via the type I IGF receptor (IGF1R) regulate growth and metastasis of multiple types of cancers. Agents targeting IGF1R are currently being tested in phase II/III clinical trials. We have previously shown that IGF1R can regulate metastasis independently of primary tumor growth in a model of high risk metastatic cancer using the MDA435/LCC6 metastatic cancer cells. Here we sought to develop an IGF1R driven metastasis signature that may be useful in selecting patients that could benefit from IGF1R targeted therapy and determine if changes in expression of the genes in the signature can be useful in predicting response. Serum starved LCC6-WT cells (with wild-type functional IGF1R) and LCC6-DN (cells with dominant negative IGF1R) were treated with IGF-I, AVE1642 (antibody against IGF1R that inhibits metastasis but not tumor growth in the mammary fat pad), or AVE1642+ IGF-I for 4 and 24 hours and microarray analysis was performed using the U133 Plus 2.0 human arrays with 47,000 transcripts. Array data were analyzed to determine genes regulated by IGF1R signaling in these cells and if disruption of signaling with AVE1642 affected genes whose expression was regulated by IGF-I signaling. A total of 91 transcripts were regulated by IGF signaling in LCC6-WT cells and AVE1642 treatment reversed the effects of IGF1R signaling. We are currently querying human tumor databases to determine if genes regulated by activation of IGF1R are associated with lymph node metastasis and poor prognosis in human tumors. Our results suggest that identifying IGF1R driven metastasis signatures may be useful to identify and monitor patients who could benefit from IGF1R targeted therapy for inhibition of metastatic disease and that patients with this IG
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B239.
Abstract B243: Kras mutation status as biomarker for response to TRAIL treatment in colorectal cancer
Authors: Van Schaeybroeck Sandra , Kyula Joan , Longley Dan , Johnston Patrick 
Published: June 2012

Abstract
Background: Kras is a member of the ras family of GTPase proteins that regulate cellular growth and survival in response to stimulation of cell surface receptors such as the Epidermal Growth Factor Receptor (EGFR). Activating mutations in the Kras gene are found in 30–50% of colorectal tumors (CRC). The presence of mutant Kras in tumors has been shown to correlate with lack of response to EGFR inhibitors. Recently, we found that CRC cells respond to TRAIL with an EGFR/HER2-mediated survival response and that by blocking this response, apoptosis is enhanced. A phase I/IIa study is currently investigating effect of AMG655 (DR5 agonist) with panitumumab (EGFR monoclonal antibody) in patients with chemorefractory CRC. The aim of this study was to evaluate the role of Kras mutational status in determining response to TRAIL alone and in combination with EGFR- or MEK-targeted therapies in a panel isogenic paired Kras wild type (WT) and mutant (MT) CRC cells.
Methods: Erk1/2 phosphorylation and expression were measured by Western blotting. Apoptosis was measured by flow cytometry andWestern blotting for PARP, caspase-8 and caspase 3 cleavage.
Results: Using paired isogenic KrasMT HCT116 and KrasWT HKH-2 and HKe-3 cell lines, we found higher basal levels of pErk1/2 in the KrasMT HCT116 cell line compared to the KrasWT HKH-2 and HKe-3 cell lines. Furthermore, we found that the HKH-2 and HKe-3 KrasWT cells were more sensitive to rhTRAIL compared to the isogenic parental and KrasMT HCT116 cell line. Moreover, we found a statistical significant increase in apoptosis when rhTRAIL was combined with the EGFR monoclonal antibodies panitumumab or cetuximab in KrasWT HKH-2 and HKe-3 cell lines but not in the parental KrasMT HCT116 cell line. In contrast, KrasMT HCT116 cell line was more sensitive to combined TRAIL/MEK-targeted therapy compared to KrasWT HKH-2 clone.
Conclusions: Our findings indicate that Kras mutations can predict response to TRAIL alone and in combination with EGFR-targeted agents in CRC cells. Inhibition of MEK1/2 in combination with TRAIL-targeted therapies may provide a strong treatment strategy in Kras mutant CRC tumors. We are currently investigating mechanism of KrasMT induced resistance to TRAIL treatment and these data will be presented during the meeting.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B243.
Abstract B253: The IGF1R inhibitor NVP-AEW541 disrupts a pro-survival and pro-angiogenic IGF-Stat3-HIF1 pathway in human glioblastoma cells
Authors: Monti Elena , Ravizza Raffaella , Molteni Roberta , Gariboldi Marzia B. 
Published: June 2012

Abstract
Glioblastomas (GBMs) typically develop hypoxic areas within the tumor mass, which for some cells results in necrosis, but for others leads to pleiotropic adaptive changes promoting tumor progression through activation of survival pathways, disruption of apoptosis, increase in invasive potential and neovascularization. The transcription factor HIF1 (hypoxia-inducible factor 1) is known to play a major role in directing this adaptive program, following stabilization of its inducible -subunit under hypoxic conditions; however, HIF1 activity can also be enhanced by oxygen-independent mechanisms upon activation of growth factor receptors and their downstream signal transduction pathways. The present study investigates a) the possible presence of a regulatory loop linking IGF1R and HIF1 in human glioblastoma cells; b) the role played by the signal transducer and activator of transcription 3 (Stat3) in this pathway; and c) the ability of the IGF1R inhibitor NVP-AEW541 (Novartis Pharma, Basel, CH) to disrupt this pathway. We show that activation of IGF1R by its ligand IGF1 causes Stat3 activation, increased levels of HIF1α and increased release of VEGF, the product of one of the major target genes for HIF1 transcriptional activity. Treatment with NVP-AEW541 reverses all these changes, and so does transfection of the cells with a dominant negative form of Stat3. Interestingly, we also observe that IGF-independent activation of HIF1, obtained in the presence of the hypoxia mimic CoCl2, results in IGF1R activation, thereby indicating that a two-way relationship exists between growth factor receptor activation and increase in HIF1 transcriptional activity; NVP-AEW541 treatment significantly reduces both HIF1α protein levels and IGF1R tyrosine-specific phosphorylation in CoCl2-treated cells. Because cells surviving under hypoxic condition often become resistant to radiotherapy and chemotherapy, modulation of the IGF1R-HIF1 pathway could be a viable approach to increase the effectiveness of conventional cytotoxic agents; as GBM typically presents hypoxic areas, this strategy might prove particularly valuable in improving the poor prognosis of patients affected by this tumor type.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B253.
Abstract B254: Extended target-coverage by selective Chk1 inhibitors enhances pharmacodynamic inhibition of Chk1 signaling and antitumor activity in vivo
Authors: Humphries Michael J. , von Carlowitz Ira , Le Huerou Yvan , Randolph Nikole , Mohr Peter J. , Wang Bin , Lyon Michael A. , Gunawardana Indrani , Chicarelli Mark , Blake Jim F. , Schrag Michael L. , Winski Shannon L. , Wallace Eli 
Published: June 2012

Abstract
Loss of coordination between cell cycle checkpoints and DNA damage repair is a fundamental feature tumor cells rely on for unregulated growth and developing chemotherapeutic resistance. The protein kinase Checkpoint kinase 1 (Chk1) is a sentinel molecule essential for cell cycle arrest at the S and G2M checkpoints, as well as regulating homologous recombination DNA repair. In tumor cells exposed to chemotherapy, Chk1 inhibition overrides cell cycle arrest and DNA repair functions, effectively driving tumor cells into a state of mitotic catastrophe and, ultimately, cell death. We have previously reported in schedule-dependence studies, using Chk1 inhibitors and irinotecan (CPT-11), that oral administration of Chk1 inhibitors allows for multi-day target-coverage, and thus continuous inhibition of Chk1 for a finite period of time, which maximizes anti-tumor efficacy. Here, we extend these studies and investigate the pharmacodynamic relationship to efficacy, as well as the specific biomarkers that are predictive of an anti-tumor effect, when Chk1 inhibitors are administered on a multi-day dosing schedule. Utilizing potent (IC50=24–27nM), selective, and orally bio-available small molecule Chk1 inhibitors of which Chk1-A and Chk1-C are representative, we find only modest inhibition of the functional biomarker phospho-cdc2, following a single dose of a Chk1 inhibitor. Alternatively, on multi-day Chk1 inhibitor dose schedules, we find dose-related pharmacodynamic inhibition of Chk1 signaling that is maximized at doses where we see significant tumor growth inhibition in efficacy experiments. Furthermore, multi-day dosing of Chk1 inhibitors induces marked inhibition of phospho-cdc2 and Rad51 protein levels, suggesting tumoricidal activity related to Chk1 inhibition is due to both checkpoint override and impairment of DNA damage repair. In human tumor xenografts administered combination therapy with gemcitabine, an orally-delivered Chk1 inhibitor dosed on a multi-day schedule shows superior efficacy over an IV administered compound. Taken together, our findings show a clear correlative relationship between pharmacodynamic target inhibition and anti-tumor activity that is exclusively achieved on multi-day dose schedules. These results demonstrate the need for prolonged Chk1 inhibition to provide robust pharmacodynamic inhibition and maximal anti-tumor efficacy.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B254.
Abstract B258: Investigating PERK biological pathway using protein/peptide microarrays and SAR with small molecule inhibitors
Authors: Otlik Hubert , Timofeevski Sergei , Quenzer Terri , Briere David , Fanjul Andrea , Alton Gordon , Ermolieff Jacques 
Published: June 2012

Abstract
Accumulation of unfolded proteins in the endoplasmic occurs when the cell is subject to stress caused by various pathological conditions such as hypoxia, viral infection, and glucose depravation. Under such stress the cell will initiate an unfolded protein response (UPR), a protective mechanism that is specifically designed to re-establish homeostasis and normal endoplasmic reticulum (ER) function. This adaptive mechanism inhibits overall protein translation, but enhances the translation of a small number of key stress response proteins that will clear the ER of unfolded proteins and send them to the cytoplasm for degradation. The UPR is initiated by several proteins such as IRE1a, ATF6a and PERK, the later being a key Ser/Thr protein kinase in UPR signaling. In response to inducers of ER stress, BiP (GRP78) dissociates from the luminal ER domain of PERK, resulting in the oligomerization, autophosphorylation, and activation of PERK which in turn phosphorylates eIF-2a on Ser51 and Nrf2 (unknown site of phosphorylation). In order to further identify potential substrates for PERK, this enzyme was tested against large protein and peptide microarrays. A significant number of proteins and peptides in the microarrays were found to be phosphorylated by PERK. After additional selection, several of these substrates were further characterized using a microfluidic mobility-shift assay and submitted to LC/MS analysis to identify the site of phosphorylation by PERK. These newly identified peptide substrates were used to develop a robust biochemical assay for the testing of small molecule inhibitors of PERK activity. A limited SAR was established for a set of compounds against PERK and two other related protein kinases, GCN2 and PKR. One of the most potent and selective PERK inhibitors was found to modulate PERK cellular signaling as evidenced by blocking the phosphorylation of (Ser51)eIF-2a as judged by Elisa and Western blot analysis.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B258.