bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract B137: Oncogenic chromosomal blocks in cancer genomes.
Authors: Wagner Joel P. , Liu Edison T.
Published: August 2014

Our preliminary observations suggest that chromosome structure rearrangements in cancer genomes are a parsimonious strategy to activate or suppress the expression of blocks of genes that contribute to cancer sustenance. We hypothesize that these rearrangements exploit the natural organization of the human genome to promote tumor development and drug resistance. We believe that in the process of cancer evolution, genes are brought together by chromosome rearrangement and then subsequently co-selected for providing a survival advantage to the cancer. In this manner, chromosome structure represents a novel means for encoding information in cancer cells, beyond the enzymatic and protein-protein interactions defining biochemical pathways. Using public data from a large collection of human cancer cell lines, we uncovered blocks of genes on each chromosome that undergo copy number alterations as a unit, which we term Cancer Syntenic Blocks (CSBs). Similar to syntenic blocks in comparative evolution, these CSBs appear to engage in rearrangements as chromosomal blocks, suggesting they may function as systems modules in cancer biology. We developed quantitative measures to identify CSBs in individual cancer types using a multi-gene network clustering approach, and showed that CSBs are enriched for cancer relevant functions. We further demonstrated that some CSBs are conserved across multiple cancer types, suggesting they may function in pan-cancer modules. We hypothesize that the component genes within a CSB do not necessarily act in one biochemical pathway, but instead may represent the coordination of pathways that contribute to a common cellular physiologic function. We also identified co-occurring sets of intra- and inter-chromosomal CSBs (both undergoing copy number gain, loss, or gain paired with loss), suggesting that multiple CSBs can act coordinately. The CSB framework can be exploited to assess systems activation of oncogenic blocks of genes in cancer, which can be used in cancer classification and in genome-based diagnostics.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B137.

Citation Format: Joel P. Wagner, Edison T. Liu. Oncogenic chromosomal blocks in cancer genomes. [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 B137.
Abstract B146: Mid-therapy FDG PET as an outcome biomarker in sarcoma patients.
Authors: Eary Janet F. , O'Sullivan Janet , O'Sullivan Finbarr , Conrad Ernest U.
Published: August 2014

Objective: To determine the prognostic biomarker capability of neo-adjuvant mid-therapy FDG PET for sarcoma monitoring.

Methods: Patients with a sampling of sarcoma subtypes presenting to clinic and treated with neo-adjuvant chemotherapy according to standard clinical practice had baseline, mid-therapy (after 2 cycles of chemotherapy) and pre-resection FDG PET studies. Tumor FDG SUV maximum at each timepoint, tumor type, location, size, gender, and histopathologic grade along with patient age were recorded. Months from baseline FDG PET to events of tumor local recurrence, metastasis, or death were determined from clinical records for comparison with imaging data. Baseline tumor uptake data, with the addition of the variable for percent difference between the baseline and mid-therapy FDG tumor maximum to describe change mid-therapy were analyzed for association with outcome in a model that included all other available covariates. Data was analyzed using univariate and multivariate Cox regression analyses to evaluate the contribution of the PET FDG response for predicting death, metastases, or tumor local recurrence.

Results: Data from 65 patient studies were analyzed. Univariate and multivariate analyses showed that the difference in FDG PET tumor maximum uptake added significantly to the prognostic ability of the model using baseline tumor uptake alone with the other clinical covariates. The median value for this difference for the group was 35.7% with a difference below that value implying a significantly higher risk for poor outcome. Additionally, Cox regression analysis showed that there is a continuous dose effect for FDG PET tumor uptake values and FDG PET percent change. Local recurrence was predicted independently from metastases.

Conclusion: Mid-neo-adjuvant therapy FDG PET tumor uptake in sarcoma patients can be used as an imaging biomarker for prediction of local recurrence, metastases, and overall survival.

Supported by NIH/NCI CA 65537 and SFI 11/PI/1027

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B146.

Citation Format: Janet F. Eary, Janet O'Sullivan, Finbarr O'Sullivan, Ernest U. Conrad. Mid-therapy FDG PET as an outcome biomarker in sarcoma patients. [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 B146.
Abstract B156: Regulation of tumor metabolism by the investigational proteasome inhibitor ixazomib in KRAS wild-type and KRAS mutant xenograft tumors.
Authors: Chattopadhyay Nibedita , Berger Allison , Garnsey James , Bernard Hugues , Koenig Erik , Lightcap Eric , Amidon Ben
Published: August 2014

The investigational proteasome inhibitor ixazomib (MLN2238) inhibits cell growth in a broad panel of solid tumor and hematological cell lines when tested in vitro. In contrast, antitumor activity in xenograft-bearing mice is model-dependent, with some solid tumor models showing no response to ixazomib treatment. A survey of 15 NSCLC and 6 colon xenograft models showed a striking relationship between the degree of antitumor activity of ixazomib and KRAS genotype. Tumors with wild-type (WT) KRAS showed higher sensitivity to ixazomib compared to the tumors harboring a KRAS activating mutation. These xenografts included cell-line-derived subcutaneous xenografts as well as patient derived primary tumors. To confirm that KRAS mutation impacts response to ixazomib, we used SW48 isogenic colon cancer cell lines, in which a KRAS-G13D mutation was introduced into KRAS-WT SW48 cells to generate stable SW48-KRAS-G13D cells. Although in vitro sensitivity to ixazomib was similar between the paired cell lines, in vivo antitumor activity was observed in only SW48 KRAS WT tumors, but not SW48-KRAS-G13D tumors. These data confirm the association of KRAS status and response to ixazomib. Since KRAS activating mutations are known to be associated with metabolic reprogramming, we performed metabolite profiling using in vivo SW48 isogenic tumor pairs treated with or without ixazomib. As expected, prior to treatment there were significant baseline differences between SW48 WT and SW48-KRAS-G13D tumor metabolite profiles in categories such as glutathione levels and glycogen breakdown intermediates, reflecting higher oxidative stress and glucose utilization in the KRAS-G13D tumors. After a single dose of ixazomib, significant metabolic regulation was noted in categories including free amino acid pools, and polyamine levels, and some of these changes were more pronounced in the SW48 KRAS WT tumors as compared to the KRAS-G13D tumors. Our data also showed activation of GCN2 mediated signaling following ixazomib treatment, possibly as a result of amino acid deprivation in the tumors. The results suggest additional non-clinical avenues to explore mechanisms of sensitivity and resistance to proteasome inhibitors in solid tumors.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B156.

Citation Format: Nibedita Chattopadhyay, Allison Berger, James Garnsey, Hugues Bernard, Erik Koenig, Eric Lightcap, Ben Amidon. Regulation of tumor metabolism by the investigational proteasome inhibitor ixazomib in KRAS wild-type and KRAS mutant xenograft tumors. [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 B156.
Abstract B163: Over-expression of STAT-3 induces anoikis resistance, promotes cell migration and metastatic potential in cancer cells.
Authors: Fofaria Neel Manoj , Srivastava Sanjay K.
Published: August 2014

Anoikis is an anchorage independent cell death. Resistance to anoikis is one of the key features of the metastatic cells. In the current study, we have shown the role of STAT-3 in anoikis resistance in various melanoma and pancreatic cancer cells. Marked anoikis was induced as such in the cells that were grown in anchorage-independent conditions. The melanoma and pancreatic cancer cells that resisted anoikis were observed to have higher rate of migration as compared to the cells that were exposed to anchorage dependent growth, as observed in cell migration and invasion assays. These anoikis resistant cells also had significantly higher expression and phosphorylation of STAT-3 at Tyr 705, than the cells that were attached to the basement membrane. Treatment of these cells with IL-6, a cytokine which phosphorylates STAT-3, prevented the induction of anoikis. STAT-3 inhibitors AG490 and piplartine induced anoikis in a concentration-dependent manner, whereas IL-6 blocked anoikis. Over-expression of STAT-3 by transfection, not only increased the anoikis resistance but also protected cancer cells from piplartine-induced anoikis, confirming the role of STAT-3 in anoikis resistance. On the other hand, silencing STAT-3 decreased the potential of cancer cells to resist anoikis. Furthermore, STAT-3 (-/-) cancer cells were more sensitive to anoikis as well as to the effect of piplartine as compared to STAT-3 (+/+) cells. The STAT-3 (+/+) cells also had enhanced migration potential as compared to STAT-3 (-/-) cells. STAT-3 (-/-) cells and the cells that were treated with PL completely failed to develop tumors when injected subcutaneously in immune-compromised mice. Moreover, these cells also failed to metastasize when injected intravenously. On the other hand, STAT-3 (+/+) cells not only formed aggressive tumors subcutaneously but also highly metastasized when injected intravenously. In summary, our results establish STAT-3 as a critical player that renders anoikis resistance to the cancer cells and enhance their metastasis potential.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B163.

Citation Format: Neel Manoj Fofaria, Sanjay K. Srivastava. Over-expression of STAT-3 induces anoikis resistance, promotes cell migration and metastatic potential in cancer cells. [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 B163.
Abstract B167: Targeting glioblastoma invasion with GSK-3 inhibitors: Rapid effects on vimentin dynamics.
Authors: Lawler Sean E. , Nowicki Michal O. , Chiocca E. Antonio
Published: August 2014

Tumor cell invasion of surrounding normal brain remains a formidable obstacle to the effective treatment of the lethal brain tumor glioblastoma. Moreover, invasion may be enhanced by radiation and bevacizumab, which are important clinical agents in glioblastoma treatment. At present there are no agents available clinically that specifically target the invading tumor cell population. We previously identified that small molecule inhibitors of the protein kinase GSK-3 (glycogen synthase kinase-3), are able to specifically block glioblastoma invasion in vitro and in vivo, where they also prolong survival in animal models bearing intracranial invasive orthotopic glioblastoma xenografts.

GSK-3 is a ubiquitous multifunctional serine/threonine protein kinase involved in many signaling pathways. To better understand the functions of GSK-3 in glioblastoma we used proteomics and gene/microRNA expression profiling to determine the molecular effects of GSK-3 inhibition in glioblastoma cells with the inhibitors Lithium chloride and 6-bromoindirubin-3’-oxime (BIO). This revealed distinct and overlapping effects of each compound, including the expected upregulation of β-catenin targets such as Axin2. Proteomics revealed major changes in the cytoskeleton, with downregulation of the EMT marker vimentin as the most significant alteration. Vimentin is an intermediate filament protein that functions as an organizer of a number of critical proteins involved in attachment, migration, and cell signaling. The downregulation of vimentin was rapid and due to alterations in its dynamics in response to GSK-3 inhibition. GSK-3 and vimentin were shown to associate with each other in glioblastoma cells, and reduction in phosphorylation of vimentin serine 38 was observed in response to treatment with inhibitors. We showed that vimentin is highly expressed in patient glioblastoma samples and higher levels of vimentin are associated with poorer prognosis in glioblastoma patients. Vimentin knockdown also reduced glioblastoma cell migration. The mechanism of action of GSK-3 inhibition in the context of glioblastoma invasion and the potential of developing a therapeutic strategy based on these observations will be discussed.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B167.

Citation Format: Sean E. Lawler, Michal O. Nowicki, E. Antonio Chiocca. Targeting glioblastoma invasion with GSK-3 inhibitors: Rapid effects on vimentin dynamics. [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 B167.
Abstract B171: Traditional Chinese medicine (TCM) herbal mixture LQ targets lung cancer metastasis.
Authors: Zhang Lei , Wu Chengyu , Zhang Yong , Liu Fang , Wang Xiaoen , Zhao Ming , Hoffman Robert M.
Published: August 2014

Traditional Chinese Medicine (TCM) compositions usually comprise multiple herbs and components that interact. In the present report, the TCM mixture LQ (gavage, 600 mg/kg/day) significantly inhibited lung cancer primary tumor growth and metastasis suggesting selective targets. LQ was efficacious against primary and metastatic cancer without weight loss in contrast to cyclophosphamide and doxorubicin, which caused significant weight loss. Survival of tumor-bearing mice was also prolonged by LQ comparable to doxorubicin. Cancer cell apoptosis was selectively induced by LQ. The results indicate that LQ can have non-toxic efficacy against metastatic lung cancer in clinically relevant orthotopic mouse and experimental metastasis models of cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B171.

Citation Format: Lei Zhang, Chengyu Wu, Yong Zhang, Fang Liu, Xiaoen Wang, Ming Zhao, Robert M. Hoffman. Traditional Chinese medicine (TCM) herbal mixture LQ targets lung cancer metastasis. [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 B171.
Abstract B186: The unexpected role of p110β in HER2 amplified and PIK3CA mutant breast cancers.
Authors: Costa Carlotta , Ebi Hiromichi , Faber Anthony C. , Nishtala Madhuri , Chul Song Young , Engelman Jeffrey A.
Published: August 2014

The PI3K pathway is alterated in up to 70% of breast cancers. Although both isoform-specific and pan-PI3K inhibitors are available, it is still unclear which compounds are more effective among the different subtypes of breast cancer. We performed time course experiments using the selective p110α inhibitor, BYL-719, in PIK3CA mutant and HER2 amplified cell lines in order to test whether p110α inhibition alone was sufficient to abrogate PI3K-AKT signaling. We observed a rebound of PIP3, the PI3K product, 24 hours after treatment in all cell lines. Notably, both PIP3 and p-AKT levels increased after 24 hours in HER2 amplified cells, while the rebound of p-AKT in PIK3CA mutant was minimal and did not correlate with PIP3 levels. Both p110β inhibitor and siRNA againt p110β were effective in blocking the PIP3 rebound observed after 24 hours of treatment with BYL-719 alone. Consistent with this, the combination of p110α and p110β inhibitors reduce cell growth in long term viability assays and induced a greater apoptotic response in comparison to BYL-719 alone. Importantly, p110α and p110β inhibitors in combination induced tumor regression in vivo, while with single agent BYL-719 we observed only tumor stasis. Finally, we demonstrated, both in vitro and in vivo, that PIP3 levels correlate with inhibitor efficacy more accurately than p-AKT in PIK3CA model. Thus, PIP3 may serve as a more effective biomarker than p-AKT levels to predict response to PI3K inhibitors in PIK3CA mutant and HER2 amplified breast cancers.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B186.

Citation Format: Carlotta Costa, Hiromichi Ebi, Anthony C. Faber, Madhuri Nishtala, Young Chul Song, Jeffrey A. Engelman. The unexpected role of p110β in HER2 amplified and PIK3CA mutant 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 B186.
Abstract B187: Pharmacodynamics of OSI-027, a dual mTORC1/mTORC2 inhibitor, in tumor and surrogate tissues: Results from the expansion phase of a first-in-man study.
Authors: Mateo Joaquin , Schoffski Patrick , Olmos David , Dumez Herlinde , Moreno Victor , Jie Fei , Poondru Srinivasu , Samberg Nancy L. , Van Tornout Jan M. , Kaye Stanley B. , LoRusso Patricia M.
Published: August 2014

Background: The kinase activity of the mammalian target of rapamycin (mTOR) involves 2 multiprotein complexes, mTORC1 and mTORC2, regulating distinct signaling pathways. We conducted a first-in-human study of OSI-027, an orally bio-available inhibitor of both mTORC1 and mTORC2, with the aim of evaluating its safety, pharmacokinetics (PK), maximum tolerated dose (MTD) and pharmacodynamics (PD). We present final results, focusing on expansion cohorts for biomarker assessments at different dose levels.

Material and Methods: Three dose-escalation arms evaluated different schedules (S) of administration; S1: once daily for 3 of every 7 days (qd 3/7d), S2: once weekly (qwk) or S3: continuous qd, in 21-day cycles. Dose limiting toxicities (DLT) were assessed in cycle 1 (CTCAE v3). Safety and PK were studied after single and multiple dosing. Expansion cohorts for biomarker assessment were initiated at different dose levels based on safety data, collecting PBMC samples and paired pre/post-treatment tumor and skin biopsies.

Results: 123 patients (pts) were treated. Overall, DLTs (n=11) were fatigue (4), elevated serum creatinine (2), cardiomyopathy (1), decreased left ventricular ejection fraction (1), hyperglycemia (1), rash (1) and bone pain (1). S3 was discontinued (MTD 35mg qd) due to renal toxicity. Based on safety data, expansion cohorts were initiated to assess PD at 90mg qd 3/7d, 120mg qd 3/7d (MTD for S1) and 240mg qwk (maximum administered dose on S2 due to high number of capsules required; MTD for S2 not reached). Cmax and AUC were dose-linear. PD inhibition in PBMC was associated with OSI-027 exposure; results of tumor and skin biopsies are presented in table 1. Stable disease (RECIST 1.0) after 24 weeks was observed in 5 pts.

Conclusions: OSI-027 modulates mTORC1/mTORC2 in a dose-dependent manner. PD in skin samples did not predict PD in tumor. While 90mg qd 3/7d inhibited target in PBMC and skin, 120mg qd 3/7d was required to achieve substantial effect in tumor but this dose was not well tolerated: 1/3 of pts required dose-reductions due to adverse events.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B187.

Citation Format: Joaquin Mateo, Patrick Schoffski, David Olmos, Herlinde Dumez, Victor Moreno, Fei Jie, Srinivasu Poondru, Nancy L. Samberg, Jan M. Van Tornout, Stanley B. Kaye, Patricia M. LoRusso. Pharmacodynamics of OSI-027, a dual mTORC1/mTORC2 inhibitor, in tumor and surrogate tissues: Results from the expansion phase of a first-in-man study. [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 B187.
Abstract B201: Targeting HIF-1α in diffuse large B cell lymphoma: Role for HDAC inhibitors.
Authors: Bhalla Savita , Evens Andrew M. , Prachand Sheila , Schumacker Paul T. , Gordon Leo I.
Published: August 2014

Hypoxia inducible factor (HIF) is important in cancer, as it regulates various oncogenic genes as well as genes involved in cell survival, proliferation, and migration. Elevated HIF-1 protein promotes a more aggressive tumor phenotype, and greater HIF-1 expression has been demonstrated to correlate with poorer prognosis, increased risk of metastasis and increased mortality. Recent reports suggest that HIF-1 activates autophagy, a lysosomal degradation pathway which may promote tumor cell survival. We show here that HIF-1α is constitutively active in multiple diffuse large B cell lymphoma (DLBCL) cell lines under normoxia and it is regulated by the PI3K/AKT pathway. PCI-24781, a pan histone deacetylase inhibitor (HDACI), enhanced accumulation of HIF-1α and induced autophagy initially, while extended incubation with the drug resulted in inhibition of HIF-1α. We tested the hypothesis that PCI-24781- induced autophagy is mediated by HIF-1α and that inhibition of HIF-1α in these cells results in attenuation of autophagy and decreased survival. We also provide evidence that autophagy serves as a survival pathway in DLBCL cells treated with PCI-24781 which suggest that the use of autophagy inhibitors such as chloroquine or 3-methyl adenine in combination with PCI-24781 may enhance apoptosis in lymphoma cells.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B201.

Citation Format: Savita Bhalla, Andrew M. Evens, Sheila Prachand, Paul T. Schumacker, Leo I. Gordon. Targeting HIF-1α in diffuse large B cell lymphoma: Role for HDAC inhibitors. [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 B201.
Abstract B22: BAY61-3606 sensitizes colon cancer cells to TRAIL-induced apoptosis by targeting TRAIL-R1 and RIPK1.
Authors: Du Jipei , Li Yan , Wang Xinyuan , Cheng Rao , Chen Degao , Zhang Ji , Wang Yufang
Published: August 2014

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) appears to be a promising candidate for cancer therapeutics because of its ability to preferentially induce apoptosis in malignant cells. However, heterogeneous sensitivity of cancer cells to TRAIL-induced apoptosis may lead to persistent growth of TRAIL-resistant cells, and preclude successful treatment of cancer by TRAIL. Here we show that that the orally available tyrosine kinase inhibitor BAY61-3606 potently enhances sensitivity of human colon cancer cells to TRAIL-induced apoptosis, and that this is associated with upregulation of TRAIL-R1 and downregulation of the receptor-interacting serine/threonine-protein kinase 1 (RIPK1). Although treatment with BAY61-3606 only caused moderate colon cancer cell death, it significantly enhanced TRAIL-induced killing. This could be efficiently blocked by the general caspase inhibitor z-VAD-fmk, indicating TRAIL primarily induced apoptosis in the presence of BAY61-3606. Interestingly, exposure of colon cancer cells resulted in upregulation of TRAIL-R1 and downregulation of RIPK1, suggesting that they may play an important role in BAY61-3606-mediated sensitization of colon cancer cells to TRAIL-induced apoptosis. Taken together, our results suggest that combination with BAY61-3606 may be a useful strategy to improve the therapeutic efficacy of TRAIL in the treatment of colon cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B22.

Citation Format: Jipei Du, Yan Li, Xinyuan Wang, Rao Cheng, Degao Chen, Ji Zhang, Yufang Wang. BAY61-3606 sensitizes colon cancer cells to TRAIL-induced apoptosis by targeting TRAIL-R1 and RIPK1. [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 B22.
Abstract B222: Dicer substrate siRNAs to MYC, B-catenin, and other target genes effectively induce in vivo target gene knockdown and tumor inhibition.
Authors: Dudek Hank , Wortham Kathleen , Arvan Rokhand , Shah Anee , Ying Bo , Cyr Wendy , Yang Hailin , Zhou Wei , Saxena Utsav , Zhou Yi , Diwanji Rohan , Holmes Ben , Farkiwala Ruchir , Shah Aalok , Brown Bob
Published: August 2014

Although there are now multiple successful examples of targeted therapeutics in cancer, many key protein targets have remained largely ‘undruggable’, including transcription factors such as B-catenin (CTNNB1) and MYC. B-catenin mediates Wnt signaling, which is overactive in many cancers including hepatocarcinoma (HCC). RNAi offers a way to reach such undruggable targets by inhibiting their expression at the mRNA level. Dicer substrate siRNAs (“DsiRNAs”) can be particularly effective for gene silencing. DsiRNAs are longer than conventional siRNAs, and therefore are substrates for processing by Dicer, after which the product RNA duplexes are incorporated into RISC, leading to target mRNA knockdown. We have used DsiRNAs to target B-catenin, MYC, and other key genes in HCC and other cancers. Through large-scale DsiRNA screening, we have identified a series of high potency DsiRNAs with picomolar to sub-picomolar IC50 values for mRNA knockdown. Lead DsiRNAs fully tolerated extensive 2’-OMe modification, retaining high potency, and lacked detectable immunostimulatory activity. To test the effect of target gene knockdown on tumor growth in vivo, we used a lipid nanoparticle (LNP) delivery system. LNP/DsiRNA particles effectively delivered to tumors in mouse tumor models, leading to rapid knockdown of target gene mRNA and protein. Knockdown of B-catenin, MYC, and other target genes strongly inhibited tumor growth. B-catenin knockdown also strongly reduced expression of the B-catenin-regulated genes Axin2 and MYC, a potential mechanism for tumor inhibition. In summary, we have developed high potency DsiRNAs to cancer target genes, and effectively delivered these DsiRNAs to tumors in vivo, resulting in inhibition of target gene expression and inhibition of tumor growth. DsiRNA therapeutics show promise as novel agents for reaching traditionally undruggable target genes.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B222.

Citation Format: Hank Dudek, Kathleen Wortham, Rokhand Arvan, Anee Shah, Bo Ying, Wendy Cyr, Hailin Yang, Wei Zhou, Utsav Saxena, Yi Zhou, Rohan Diwanji, Ben Holmes, Ruchir Farkiwala, Aalok Shah, Bob Brown. Dicer substrate siRNAs to MYC, B-catenin, and other target genes effectively induce in vivo target gene knockdown and tumor 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 B222.
Abstract B226: MiR-148a dependent apoptosis of bladder cancer cells is mediated by the epigenetic modifier DNMT1.
Authors: Lombard Alan P. , Libertini Steve , Costanzo Nicole , Lim Rebecca , Mudryj Maria
Published: August 2014

Introduction: MiRNAs are now recognized as major players in cancer. MiR-148a has been shown to be a tumor suppressor in the context of several cancers including prostate, gastric, and lung but a study investigating its role in bladder cancer has never been performed. Here we sought to characterize the expression and role of miR-148a in bladder cancer.

Methods: Real time PCR was used to assess the levels of miR-148a across several bladder cancer cell lines. MiR-148a mimics were employed in T24 and UM-UC-3 cells to assess proliferation by CCK-8 proliferation assay, colony formation assay, and flow cytometry. Mimics were also used to assess apoptosis by immunoblot and annexin-V staining. SiRNA was used to knock-down DNMT1 to phenocopy miR-148a treatment. CCK-8 proliferation assays and crystal violet staining were used to assess the effects of miR-148a added to either cisplatin or doxorubicin on T24 and UM-UC-3 cells.

Results: All bladder cancer cell lines had significantly reduced expression of miR-148a than that of a control immortalized urothelial cell line. MiR-148a mimic treatment of T24 and UM-UC-3 cells lead to large decreases in viability. Flow cytometry demonstrated an S-phase arrest in miR-148a mimic treated cells versus control oligo treated cells. Immunoblots for cleaved caspase-3 and cleaved PARP along with annexin-V staining showed strong induction of apoptosis in miR-148a mimic treated cells. MiR-148a was shown to target DNMT1 and DNMT1 knock-down was able to phenocopy results from miR-148a mimic treatment suggesting DNMT1 is downstream of miR-148a. Finally, we found that miR-148a can be used with either cisplatin or doxorubicin for an additive effect in inducing apoptosis.

Conclusions: Our work demonstrates for the first time that miR-148a plays a tumor suppressive role in bladder cancer and suggests it could be used as a novel therapeutic agent either alone or in conjunction with chemotherapeutics.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B226.

Citation Format: Alan P. Lombard, Steve Libertini, Nicole Costanzo, Rebecca Lim, Maria Mudryj. MiR-148a dependent apoptosis of bladder cancer cells is mediated by the epigenetic modifier DNMT1. [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 B226.
Abstract B229: TBKI kinase inhibition blocks RANTES secretion and exhibits minimal tumor growth inhibition in oncogenic Ras-driven tumor models.
Authors: Van Horn Robert , Yin Tinggui , Zhang Xiaoyi , Yu Chunping , Zhang Youyan , Gong Xue-Qian , Buchanan Sean , Ye Xiang S. , McMillen William , Barda David , Peng Sheng-Bin
Published: August 2014

TANK-binding kinase 1 (TBK1) is a non-canonical IKK family member and plays a critical role in innate immunity by modulating cytokine production, interferon, and NF-kB signaling. It is recently reported that TBK1 directly engages Akt survival signaling to support oncogenic Ras-driven transformation. TBK1 is also identified as a synthetic lethal partner in KRas mutant NSCLC through systematic RNA interference. In this study, we have characterized LSN3090729, a 4-aryl-2-aminopyrimidine derivative as a selective TBK1 kinase inhibitor. Biochemical and cellular analyses demonstrate that LSN3090729 is a potent TBK1 kinase inhibitor, and selectively inhibits TBK1 based on in vitro activities in biochemical assays developed with a panel of protein kinases. In Panc-1, a pancreatic tumor cell line with KRas mutation, LSN3090729 inhibits EGF-induced phosphorylation of AKT at both Thr308 and Ser473 sites. Pharmacokinetic analysis shows that LSN3090729 has an over 70% of oral bioavailability with an acceptable half life in rodents. In a mouse pharmacology model, LSN3090729 blocks LPS-induced RANTES secretion in a dose-dependent manner with 67%, 79%, and 90% inhibition at 10, 30, and 100 mg/kg, respectively. LSN3090729 is assessed for its anti-proliferation activities in vitro in a panel of tumor cells with KRas mutation or other genetic background. The sensitivity of these tumor cells to LSN3090729 in two dimensional proliferation or three dimensional soft agar growth assays appears not correlated with status of KRas mutation. In xenograft models of HCT116 and Panc-1, both with a KRas mutation, treatment of LSN3090729 exhibits minimal anti-tumor growth activities, suggesting that a combination approach might be required for TBK1 kinase inhibition to be effective in cancer settings.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B229.

Citation Format: Robert Van Horn, Tinggui Yin, Xiaoyi Zhang, Chunping Yu, Youyan Zhang, Xue-Qian Gong, Sean Buchanan, Xiang S. Ye, William McMillen, David Barda, Sheng-Bin Peng. TBKI kinase inhibition blocks RANTES secretion and exhibits minimal tumor growth inhibition in oncogenic Ras-driven tumor models. [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 B229.
Abstract B254: Targeted disruption of the EZH2-EED complex inhibits EZH2-dependent cancer.
Authors: Kim Woojin , Bird Gregory H. , Neff Tobias , Guo Guoji , Kerenyi Marc A. , Walensky Loren D. , Orkin Stuart H.
Published: August 2014

Enhancer of zeste homolog 2 (EZH2) is the histone lysine N-methyltransferase component of the Polycomb repressive complex 2 (PRC2), which, in conjunction with embryonic ectoderm development (EED) and suppressor of zeste 12 homolog(SUZ12), regulates cell lineage determination and homeostasis. Enzymatic hyperactivity of EZH2 has been linked to aberrant repression of tumor suppressor genes in diverse cancers. Here, we report the development of stabilized a-helix of EZH2 (SAH-EZH2) peptides that selectively inhibit H3 Lys27 trimethylation by dose-responsively disrupting the EZH2-EED complex and reducing EZH2 protein levels, a mechanism distinct from that reported for small-molecule EZH2 inhibitors targeting the enzyme catalytic domain. The essential α-helical domain of EZH2 (residues 40-68) that engages EED established the basis for designing hydrocarbon-stapled derivatives to disrupt the specific protein interaction. Non-natural amino acids with olefinic side chains were substituted at (i, i + 4) positions within the EZH2 α-helical sequence, followed by ruthenium-catalyzed olefin metathesis, to yield SAH-EZH2 peptides. Our lead, cell-permeable analog effectively targeted EED in situ, dissociated the EZH2-EED complex and impaired the function of PRC2, as reflected by reduction of the H3K27me3 and EZH2 protein levels, and increased expression of PRC2-regulated cell differentiation marker genes. In response to SAH-EZH2 treatment, murine MLL-AF9 leukemia cells, which are PRC2-dependent, manifested growth arrest and monocyte-macrophage differentiation, in accordance with the phenotypic consequences of shRNA-mediated reduction of EZH2 (or EED) or genetic ablation of Ezh2 (or Eed). In evaluating SAH-EZH2 activity alongside the small-molecule EZH2 inhibitor GSK126 in a series of B-cell lymphoma lines, we observed sequence-specific antiproliferative responses, transcriptional modulation, cellular specificity and a distinct mechanism of action for SAH-EZH2.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B254.

Citation Format: Woojin Kim, Gregory H. Bird, Tobias Neff, Guoji Guo, Marc A. Kerenyi, Loren D. Walensky, Stuart H. Orkin. Targeted disruption of the EZH2-EED complex inhibits EZH2-dependent cancer. [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 B254.
Abstract B255: Development of hybrid small molecules that induce degradation of estrogen receptor-alpha and necrotic cell death in breast cancer cells.
Authors: Okuhira Keiichiro , Demizu Yosuke , Hattori Takayuki , Ohoka Nobumichi , Shibata Norihito , Nishimaki-Mogami Tomoko , Okuda Haruhiro , Kurihara Masaaki , Naito Mikihiko
Published: August 2014

Breast cancer is the leading cause of cancer death in women. Most of the primary breast cancers express estrogen receptor α (ERα) and they show estrogen-dependent proliferation. Since tamoxifen antagonizes estrogen in breast cancers, it is widely used to treat the primary breast cancers. However, tamoxifen also shows a partial agonistic activity in different tissues and cellular context, which sometimes causes a detrimental effect.

An alternative strategy to kill the estrogen signaling is to downregulate ERα protein. We have developed a protein knockdown system to induce degradation of target proteins via the ubiquitin-proteasome system (UPS) in cells. The molecules for protein knockdown, which we named SNIPER (Specific and Non-genetic IAP-dependent Protein ERaser), are composed of two different ligands connected by a linker; one is a ligand for cellular inhibitor of apoptosis protein 1 (cIAP1) and the other is a ligand for a target protein. Accordingly, SNIPER is expected to crosslink a ubiquitin ligase cIAP1 and the target protein in the cells, thereby inducing the cIAP1-mediated ubiquitylation and proteasomal degradation of the target protein.

By using tamoxifen as a ligand for ERα, we developed novel SNIPER to knockdown ERα protein. SNIPER(ER) induced degradation of ERα and inhibited estrogen-dependent expression of pS2 gene in an estrogen-dependent breast cancer MCF-7 cells. Intriguingly, after the ERα degradation, the SNIPER(ER)-treated MCF-7 cells undergo rapid cell death. Detailed analysis indicated that SNIPER(ER) caused necrotic cell death accompanied by a release of HMGB1, and reactive oxygen species (ROS) mediate the necrotic cell death in the SNIPER(ER)-treated MCF-7 cells. These results indicate that SNIPER(ER) induces ERα degradation, ROS production and necrotic cell death, implying a therapeutic potential of SNIPER(ER) as a lead for the treatment of ERα-positive breast cancers.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B255.

Citation Format: Keiichiro Okuhira, Yosuke Demizu, Takayuki Hattori, Nobumichi Ohoka, Norihito Shibata, Tomoko Nishimaki-Mogami, Haruhiro Okuda, Masaaki Kurihara, Mikihiko Naito. Development of hybrid small molecules that induce degradation of estrogen receptor-alpha and necrotic cell death in breast cancer cells. [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 B255.
Abstract B272: Rationale for combinatorial therapeutics to inhibit BRAF fusion activation.
Authors: Sievert Angela Jae , Lang Shih-Shan , Silva Amanda , Brewington Danielle , Mueller Sabine , Haas-Kogan Daphne A. , Storm Phillip B. , Resnick Adam C.
Published: August 2014

We have previously shown that pediatric gliomas harbor BRAF mutations, including the canonical BRAF V600E mutation as well as BRAF fusion genes. KIAA1549 was the first fusion partner identified in gliomas, and more recently several other partners have been found albeit at a much lower frequency. Regardless of the partnered gene, all of the BRAF fusions (BRAF-f) retain the BRAF kinase domain but lose the N-terminal regulatory domain. Our recently published work has demonstrated the KIAA1549-BRAF fusion is resistant to and instead undergoes paradoxical activation in response to PLX4720, a research analog of the BRAF inhibitor vemurafenib. In contrast, the second generation "paradox-breaking" inhibitor PLX8394 successfully targeted KIAA1549-BRAF in vitro. We now demonstrate PLX8394's efficacy in vivo in models of BRAF-f. However, as has been demonstrated for vemurafenib, single agent targeting with PLX8394 can give rise to emergent resistance through activation of the PI3K/mTOR pathway, suggesting additional and/or combinatorial targeting of pathways may be necessary to prevent resistance in BRAF-f expressing cells. Using BRAF-f expressing cells we have characterized mechanisms of emergent resistance and combinatorial targeting approaches targeting MEK and PI3K/mTOR pathways. As there are ongoing clinical trials with everolimus and MEK inhibitors in pediatric gliomas, a strong rationale exists for combinatorial mTOR and MEK inhibitors in treating tumors that harbor BRAF-f.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B272.

Citation Format: Angela Jae Sievert, Shih-Shan Lang, Amanda Silva, Danielle Brewington, Sabine Mueller, Daphne A. Haas-Kogan, Phillip B. Storm, Adam C. Resnick. Rationale for combinatorial therapeutics to inhibit BRAF fusion activation. [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 B272.
Abstract B3: Anti-angiogenic properties of FAK-VEGFR3 scaffold inhibitors, C9 and C10.
Authors: Agharkar Priyanka A. , Ethirajan Manivannan , Liao Jianqun , Yemma Michael , Buckley Brian , Chernov Mikhail , Cance William , Pandey Ravindra , Kurenova Elena
Published: August 2014

Introduction: Focal adhesion kinase (FAK) and vascular endothelial growth factor receptor 3 (VEGFR3) are tyrosine kinases, which function as key modulators of survival and metastasis signals in cancer cells. We have previously shown that VEGFR3 binds to the FAT domain of FAK and this interaction promotes the survival of tumor cells. We developed novel small molecule compounds C9 and C10 which specifically bind and inhibit the FAK-VEGFR3 interaction. Both these compounds inhibit cancer cell proliferation, induce apoptosis, disrupt the FAK-VEGFR3 signaling axis, and significantly inhibit tumor growth in xenograft mouse models of breast and pancreatic cancer. Since FAK and VEGFR3 have been implicated in tumor angiogenesis, we investigated the potential anti-angiogenic effects of C9 and C10.

Methods: Binding of C9 and C10 to the FAT domain of FAK was tested using fluorescence polarization. Effects of C9 and C10 were tested in vitro by MTS assay (viability) and tube formation assay using HUVEC cells. Directed in vivo angiogenesis assay (DIVAA) kit was used to determine anti-angiogenic effects of both compounds. Single agent efficacy of C9 and C10 was tested in a pancreatic xenograft mouse model for 30 days. Mouse tumor tissues were analyzed for markers of proliferation (Ki67), endothelial vessels (CD31), and lymphangiogenic vessels (LYVE1) using immunohistochemistry.

Results: Fluorescence polarization confirmed that C9 and C10 effectively bind to the FAT domain of FAK. C9 and C10 reduced cell viability of HUVEC cells and dramatically decreased tube formation by reducing total branching points, total loops and total tube length in a dose and time dependent manner. DIVAA assay confirmed that C9 and C10 significantly reduced the formation of endothelial blood vessels as compared to untreated groups. In vivo, 30 days treatment with low doses of C9 and C10 as single agents led to 40% to 45% reduction in tumor volume (P<0.05). Further analyses of these mouse tumors confirmed the anti-angiogenic effects of C9 and C10.

Conclusions: We have shown that targeting the FAK-VEGFR3 protein protein interaction site allows for dual inhibition of tumor proliferation as well as tumor angiogenesis. This study highlights the importance of oral-based small molecule inhibitors that might impact the therapeutic management of solid tumors.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B3.

Citation Format: Priyanka A. Agharkar, Manivannan Ethirajan, Jianqun Liao, Michael Yemma, Brian Buckley, Mikhail Chernov, William Cance, Ravindra Pandey, Elena Kurenova. Anti-angiogenic properties of FAK-VEGFR3 scaffold inhibitors, C9 and C10. [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 B3.
Abstract B43: A subset of gastric cancers with EGFR amplification and overexpression respond to cetuximab therapy.
Authors: Zhang Lianhai , Yang Jie , Chen Yiyou , Cai Jie , Song Xiaoming , Huang Xuesong , Deng Jianyun , Chen Dawei , Yang Mengmeng , Li Shuangxi , Wu Aiwen , Li Ziyu , Li Zhongwu , Liu Yiqian , Wery Jean-Pierre , Li Henry , Ji Jiafu
Published: August 2014

Gastric carcinoma (GC) is a common cancer of high mortality and particularly prevalent in East Asia. There are only a few treatment options: surgery, chemotherapy, as well as Herceptin® for a small subset of patients with erbb2 amplification. Cetuximab has been approved for CRC (colorectal) and SCCHN, but not yet for gastric carcinoma. Cetuximab, combined with capecitabine/cisplatin, has recently been tested in Phase III clinical trial (EXPAND) in GC patients (1), but failed to demonstrate benefit over the existing chemotherapy (capecitabine/cisplatin). One of the reasons for the failure is only small subset of patients responding to cetuximab, which constitutes little effects on large trial populations, while the identity of the responders yet to be revealed. One of the keys to a successful search for effective treatment is the development of experimental model that truly mimics patient conditions. Patient derived xenograft (PDX or HuPrime®) is believed to best mimic human cancers (2). Recently, we have established a cohort of ∼70 GC xenograft (PDX) models from Asian and Caucasian patients. In the present study, we conducted a mouse clinical trial (MCT, or PDX trial) to test cetuximab in a cohort of GC-PDX, aiming at identifying those responsive to cetuximab. Interestingly, our trial result identified 4 of 20 (20%) GC-PDX responded to cetuximab. Genome-wide profiling and additional investigations revealed that high EGFR mRNA expression and immunohistochemistry score (3+) are associated with tumor growth inhibition. Furthermore, EGFR amplification were observed in 4/4 (50%) responders by DNAchip analysis or 2/4 confirmed with FISH analysis, with average copy number 5.8 and >15 respectively. Our data suggest that a GC subtype with EGFR amplification and overexpression benefit from cetuximab treatment.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B43.

Citation Format: Lianhai Zhang, Jie Yang, Yiyou Chen, Jie Cai, Xiaoming Song, Xuesong Huang, Jianyun Deng, Dawei Chen, Mengmeng Yang, Shuangxi Li, Aiwen Wu, Ziyu Li, Zhongwu Li, Yiqian Liu, Jean-Pierre Wery, Henry Li, Jiafu Ji. A subset of gastric cancers with EGFR amplification and overexpression respond to cetuximab therapy. [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 B43.