bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 869: Potent in vitro and in vivo anti-tumor activity of PI3K inhibitor BAY 80-6946 and MEK inhibitor BAY 86-9766 in preclinical biliary tract cancer models
Authors: Haegebarth Andrea , Haike Katja , Haike Katja , Paul Juliane , Mumberg Dominik , Ziegelbauer Karl , Liu Ningshu
Published: August 2012

Biliary tract cancer (BTC) includes a spectrum of genetically diverse invasive adenocarcinomas consisting intra- and extrahepatic cholangiocarcinoma (CC), and carcinoma arising from the gall bladder (GBC). Only 10% of patients diagnosed with early-stage disease are considered candidates for surgical resection, which offers the only chance for cure. The prognosis is poor for the majority of patients with locally advanced or metastatic BTC with a median survival of under a year. Recently, high incidence of oncogenic mutations such as KRAS, BRAF, PIK3CA and EGFR were found in BTC patients, potentially rendering these patients sensitive to inhibitors of these pathways. We report on preclinical evaluation of highly potent and selective PI3K inhibitor BAY 80-6946 and allosteric MEK inhibitor BAY 86-9766 in BTC as single agent and in combination. In vitro profiling a panel of BTC tumor cell lines indicated that KRASmut and PIK3CAmut cell lines were sensitive to MEKi (BAY 86-9766) and PI3Ki (BAY 80-6946), respectively, compared to the cell lines with wild type KRAS and PIK3CA. However, although MEKi BAY 86-9766 inhibited proliferation with IC50s of 147 nM in HuCCT-1 (KRASG12D) and 137 nM in EGI-1 (KRASG12D) cell lines, it can neither reach IC90 nor induce tumor apoptosis at concentration up to10 µM, indicating activation of additional survival pathways in these KRASmut BTC cell lines. When combining MEKi BAY 86-9766 with PI3Ki BAY 80-6946 in KRASmut EGI-1, IC90 could be reached at much lower concentrations, e.g. 108 nM of MEKi with 81 nM of PI3Ki in EGI-1 cells. Furthermore, strong activation (10-fold) of caspase3/7 was observed when EGI-1 cells were treated with 700 nM of MEKi with 230 nM of PI3Ki. To confirm the observed in vitro synergies, anti-tumor efficacy of BAY 80-6946 and BAY 86-9766 in mono- as well as combination therapy was evaluated in a set of human BTC xenograft models. Similar to the in vitro results, robust in vivo antitumor activities were observed in the PI3Ki and MEKi combination groups compared to monotherapy arms. Further detailed molecular mechanism on the synergistic inhibition of BTC tumor growth by combination of PI3K and MEK inhibitors, as well as in vitro and in vivo comparison to the chemotherapeutics will be presented. In conclusion, PI3Ki and MEKi combination therapy might open a new treatment paradigm for BTC to be developed in clinic.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 869. doi:1538-7445.AM2012-869
Abstract 872: Identification of romidepsin (FK228) and its analogs as HDAC/PI3K dual inhibitors
Authors: Saijo Ken , Katoh Tadashi , Shimodaira Hideki , Oda Akifumi , Takahashi Ohgi , Ishioka Chikashi
Published: August 2012

Activation of phosphatidylinositol 3-kinase (PI3K) signaling is involved in carcinogenesis and cancer progression. Therefore, inhibitors targeting PI3K are considered to be candidate drugs for cancer therapy. Indeed, some PI3K inhibitors have entered clinical trials, but efforts are still underway to develop new PI3K inhibitors. To discover novel PI3K inhibitors, we took advantage of a drug screening system by using the yeast Saccharomyces cerevisiae with deleterious mutations in ATP-binding cassette transporter genes. This is because wild-type yeast employs drug efflux pumps for reducing intracellular drug concentrations. The screening system is based on growth inhibition induced by overexpression of membrane localized p110α in yeast, in which no endogenous p110 homolog is expressed. However, compounds with the ability to inhibit PI3K can rescue cells from p110α induced growth inhibition. Using this system, we screened the deposited chemical library of the Screening Committee of Anticancer Drugs (SCADS). As a result, the histone deacetylase (HDAC) inhibitor romidepsin (FK228) and its novel analogs were isolated. In vitro PI3K activity assays confirmed that these compounds directly inhibit PI3K activity at μM-range concentrations. FK-A5 analog was the most potent inhibitor. Western blotting revealed that these compounds inhibit phosphorylation of v-akt murine thymoma viral oncogene homolog (AKT) and downstream signaling components. Molecular modeling of the PI3K-FK228 complex indicated that FK228 binds to the ATP binding pocket of p110α. At µM range concentrations, FK228 and FK-A5 exhibit potent cytotoxicity even in HDAC inhibitor-resistant cells. Fluorescence activated cell sorting (FACS) and western blotting indicated apoptosis as the cause of cell death. Furthermore, it was suggested that HDAC/PI3K dual inhibitory activity of FK228 and FK-A5 at µM range concentrations contributed to the induction of potent apoptosis because of the following reasons. 1) FK228 or FK-A5 within µM range inhibited AKT phophorylation and acetylated histones simultaneously. 2) The apoptosis induction by FK228 or FK-A5 at µM range concentrations was mimicked by combination of HDAC inhibitor and PI3K inhibitor. In conclusion, we demonstrated that FK228 and its analogs directly inhibited PI3K activity and induce potent apoptosis exhibiting HDAC/PI3K dual inhibition at µM range concentrations. In future, optimizing potency of FK228 and its analogs against PI3K may contribute to the development of novel HDAC/PI3K dual inhibitors for cancer treatment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 872. doi:1538-7445.AM2012-872
Abstract 88: Stabilizing but not activating β-catenin by E-cad/CTF2
Authors: Hsu Sheng-Chieh
Published: August 2012

E-cadherin is an important mediator of cell-cell adhesion and plays a vital role to modulate intracellular signaling pathways. E-cadherin binds p120catenin (p120) and β-catenin at cadherin homology 2 (CH2) domain and CH3 domain, respectively. Recent studies show E-cadherin could be cleaved by γ-secretase and released the intracellular C-terminal fragment 2 (E-cad/CTF2) to regulate the p120-kaiso mediated signaling pathway in the nucleus. However, the functional effect of E-cad/CTF2 on its binding partners, β-catenin and p120, remains elusive. Here, we show E-cad/CTF2, like full-length E-cadherin, can interact and increase the expression of β-catenin. Using reverse transcription-quantitative PCR (RT-qPCR), the transcription of β-catenin mRNA is not affected by the expression of E-cad/CTF2 or E-cadherin. Interestingly, while the nuclear expression of β-catenin is enhanced by E-cad/CTF2 or NLS-tagged E-cad/CTF2, the transcriptional activity of β-catenin does not increase. It indicates the interaction between E-cad/CTF2 and β-catenin is much stronger then TCF4/β-catenin complex. This study provides the evidence that the transcriptional activity of β-catenin is not activated by E-cad/CTF2 although the stability of β-catenin is greatly enhanced by E-cad/CTF2.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 88. doi:1538-7445.AM2012-88
Abstract 884: Basonuclin1 (BNC1): A novel therapeutic target in ovarian cancer identified through integrative TCGA-based functional genomic analysis
Authors: Wu Sherry Y. , Unruh Anna K. , Bartholomeusz Geoffrey , Ivan Cristina , Pecot Chad V. , Rupaimoole Rajesha , Han Hee-Dong , Bottsford-Miller Justin , Tucker Susan L. , Coleman Robert L. , Lopez-Berestein Gabriel , Baggerly Keith A. , Sood Anil K.
Published: August 2012

High-grade serous ovarian cancer (HGS-OvCa) is the most common and lethal type of ovarian carcinoma. While TCGA provides comprehensive genomic profiling of clinically annotated HGS-OvCa tumors, identification of novel therapeutic targets using this dataset is still needed. We coupled TCGA mRNA expression and clinical response data to systematically identify genes which could alter progression of HGS-OvCa and investigated associated alterations in DNA promoter methylation and microRNA expression. For selected targets, we also used siRNA functional studies to clarify gene-specific effects. We identified 102 genes as up-regulated in tumors from patients whose cancer had progressed within 7 months of diagnosis (chemo-resistant group: 53 cases) compared to tumors from patients who had no disease progression for more than 3 years (chemo-sensitive group: 57 cases). These genes had two-sample t-test p-values < 0.05 according to level 3 TCGA data from both Agilent and Affymetrix platforms. Basonuclin1 (BNC1), a transcription factor which regulates ribosomal biogenesis, cell proliferation, and epithelial differentiation, was one of the key targets identified. Its expression was found to be increased by more than two-fold (Agilent platform; p=0.001) in chemo-resistant tumors. While no significant associated changes in microRNA expression were evident in TCGA for the BNC1 gene, we found that the expression of BNC1 negatively correlated with the degree of methylation at the promoter region of transmembrane 4 superfamily member 1, TM4SF1 (-0.42, Agilent platform), a known up-regulated pro-angiogenic gene in ovarian cancer. Importantly, the siRNA functional study had revealed a 35% reduction in cell viability in cisplatin-resistant A2780-CP20 cells following BNC1 siRNA treatment, and a further 15% reduction was noted when the cells were treated with cisplatin at the IC30 concentration determined using the chemo-sensitive parental cell line. Overall, our results demonstrate (a) the feasibility of using TCGA data, coupled with functional siRNA studies, to identify novel targets for the treatment of ovarian cancer and (b) the potential of targeting BNC1 as a treatment strategy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 884. doi:1538-7445.AM2012-884
Abstract 885: Integrated analysis of colorectal cancer cell lines reveals an amplicon driver which may be involved in platinium resistance
Authors: Briffa Romina , Harrison David J. , Faratian Dana
Published: August 2012

Background: First line adjuvant treatment for colorectal cancer (CRC) is 5-fluorouracil and the platinum compound oxaliplatin. New targeted therapies such as cetuximab and PI3K/mTOR inhibitors are being developed in order to improve therapeutic outcomes. However, intrinsic and acquired resistance is common and selecting patients who are likely to respond remains a clinical and pathological challenge. The aim of this study is to identify new targets for therapy using an integrated genomic, transcriptomic, proteomic, and functional analysis of CRC cell lines. Methods: Cell proliferation assays (AlamarBlue) were carried out on a panel 15 colorectal cancer cell lines. IC50s were established for 5-fluoruracil, oxaliplatin, and BEZ-235, a PI3K/mTOR inhibitor. Cell lines were profiled using reverse phase protein arrays (RPPA) for protein expression, Illumina gene expression analysis, array comparative genomic hybridization (aCGH; NimbleGen 135k chips) and targeted sequencing of hotspot mutations. Associations of mutations, transcript, copy number variations and proteome with drug sensitivity were established using correlation coefficients and integrated network analysis. Validation of copy number gains and losses was performed in primary tumors using Oncomine to interrogate public databases. Results: IC50s varied from resistant to highly sensitive for all three compounds. BRAF V600E mutation was significantly associated with response to 5 fluorouracil (p = 0.006). There were 17 regions of recurrent amplification across 14 cell lines and 48 regions of loss. The frequently and highly amplified regions included 8q24.13 - 8q24.21 which was significantly correlated with oxaliplatin response (p = 0.031), and amplified in 11% of primary CRCs on interrogation of public databases. This amplified region contains the putative oncogene TRIB1, a cell signaling regulator, which was correlated with gene expression across the cell lines and was found to be significantly correlated to the AKT (p=0.026), phosphor-mTOR (Ser2481) (p = 0.017) and phosphoSRC (Thr24) (p = 0.020) protein expression. The recurrently deleted regions included 3p14.2 which was significantly associated with response to the PI3K/mTOR inhibitor BEZ235 (p=0.031). This region was found to be significantly correlated with MEK (p=0.042) and phosphoCDK2 (Thr160) (p=0.018) protein expression, and contained the putative tumor suppressor gene FHIT, a hydrolase involved with purine metabolism. Conclusions: TRIB1 is a potential oncogenic driver in CRC which may be associated with therapeutic resistance to platinum compounds.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 885. doi:1538-7445.AM2012-885
Abstract 889: Integration of centrosome-associated and kinase-related screens to identify centrosome amplification-related synthetic lethal interactions
Authors: Drosopoulos Konstantinos , Scott Carly , Tang Chan , Linardopoulos Spiros
Published: August 2012

Centrosome amplification is one of the most commonly observed abnormalities in human cancer and is associated with increased chromosome instability (CIN), aneuploidy and tumor progression. Cancer cells have been shown to cluster supernumerary centrosomes in a bipolar fashion in mitosis, thus preventing the formation of lethal multipolar spindles. We have developed isogenic cell lines, which enable us to identify genes which selectively kill tumor cells with centrosome amplification. The model is based on the generation of genomically stable human colon cancer DLD1 diploid and tetraploid (DLD1-T) cells with normal centrosome numbers and genomically unstable DLD1 intermediate (DLD1-I) with extra centrosomes generated by transiently blocking cytokinesis. Diploid and tetraploid populations did not show significant differences in gene expression, fitness, rate of spontaneous apoptosis, centrosome amplification and mitotic abnormalities. However, growth rate examination of the generated isogenic cell lines showed a slight increase in doubling time of DLD1-I clones, possibly due to a longer activation of the mitotic checkpoint machinery to allow time for microtubule attachment and centrosome clustering. To identify genes that their ablation leads to a selective cell killing of centrosome amplified cancer cells by centrosome declustering, we envisaged two parallel paths of investigation, an siRNA and a chemical library screening with a two-fold readout assay: a cell viability and a spindle morphology phenotypic assay by high-content microscopy. This approach allowed us to identify target genes and generate networks of genes that specifically kill cells with centrosome amplification by preventing centrosome clustering.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 889. doi:1538-7445.AM2012-889
Abstract 896: Enhancing mTOR targeted therapy in bladder cancer
Authors: Becker Marie N. , Copland John A. , Williams Christopher R.
Published: August 2012

Bladder cancer is the 4th most commonly diagnosed cancer in the United States. Because superficial bladder cancer (SBC) recurs in about 60% of cases, standard treatment involves tumor resection followed by intravesical therapies to prevent recurrence, as well as lifelong periodic cystoscopy. There is an urgent need for better intravesical therapies to prevent both the recurrence and progression of SBC. The Mammalian Target Of Rapamycin (mTOR) complex is upregulated in many bladder cancer tumors. We have targeted both the mTORc1 and mTORc2 complexes with drugs that inhibit both complexes. We used PP242 and a second inhibitor, OSI-027, which is currently in a phase I clinical trial for solid tumors (NCT00698243). Our in vitro model targets cell proliferation in three bladder cancer cell line (HT1376, T24 and UM-UC-3). Both drugs are effective in inhibiting the growth of bladder cancer cell lines with IC50 values between 0.6 and 18µM. In comparison with rapamycin, both drugs demonstrate effects on downstream targets of both the mTORc1 and mTORc2 pathways including 4EBP1 and pAkt. Receptor tyrosine kinases are another therapeutic target for bladder cancer. Lapatinib which targets EGFR and Her3, in combination with OSI-027 forms a highly synergistic treatment that inhibits bladder cancer cell line growth. Downstream molecular targets of the combination therapy, including the apoptosis markers PARP and caspase 3, were evaluated by Western blots. Our in vitro data suggests that a combination of dual mTOR inhibitors with RTK inhibitors may provide a novel effective therapeutic treatment for bladder cancer. Future studies of the in vivo efficacy of these drug combinations in a mouse model are planned.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 896. doi:1538-7445.AM2012-896
Abstract 903: The IKKα kinase is a potential therapeutic target in K-Ras-induced lung cancer
Authors: Basseres Daniela S. , Ebbs Aaron , Cogswell Patricia C. , Levantini Elena , Baldwin Albert S.
Published: August 2012

Lung cancer is the leading cause of cancer deaths in the world. In lung cancer, K-Ras oncogenic mutations are widespread, and compounds used to target the biological activity of the Ras proteins failed in clinical trials. Therefore, it is imperative to identify novel therapeutic targets that reduce K-Ras-induced lung tumorigenesis. We have previously shown that K-Ras-induced lung tumorigenesis is potentiated by the subunit p65 of the transcription factor NF-κB; and that K-Ras-induced NF-κB activation in the lung requires IKKα. Therefore, we hypothesized the following: (1) the IKKα kinase promotes K-Ras-induced oncogenesis; and (2) pharmacological inhibition of IKKα activity will be beneficial therapeutically. We used genetic and/or pharmacological approaches to inactivate IKKα in primary lung epithelial cells transformed by K-Ras, as well as K-Ras-positive lung cancer cell lines, and determined that IKKα inhibiton reduces oncogenic properties in vitro. In addition we used a highly specific IKKα inhibitor (CmpdA, Bayer) to treat a K-Ras-induced lung cancer mouse model combined with loss of the tumor suppressor p53 (LSL-K-RasG12D/p53fl/fl). We chose this model for the following reasons: (1) K-Ras activation coupled to p53 loss leads to aggressive lung adenocarcinomas in mice that better resemble human lung tumors; (2) lung cancer patients harboring K-Ras oncogenic mutations frequently display p53 inactivation; and (3) it has been recently demonstrated that p53 loss can enhance NF-κB activation by K-Ras in lung tumors. To induce concomitant K-Ras activation and p53 loss in murine lung epithelial cells, we infected the lungs of LSL-K-RasG12D/p53fl/fl mice by intranasal administration of a Cre-expressing adenovirus (AdCre). Two treatment regimens were used to treat infected animals: CmpdA was either administered daily for 2 weeks immediately following AdCre infection or daily for 4 weeks starting 8 weeks post-infection. In either case, mice treated with CmpdA presented smaller and lower grade tumors than mice treated with placebo. These results show that IKKα promotes lung cancer growth and progression both in vitro and in vivo. In addition, we have shown that pharmacological administration of an IKKα inhibitor slows lung tumor growth and progression in vivo, supporting our hypothesis that IKKα inhibition therapy will have clinical benefits in lung cancer. This research is supported by a FAMRI YCSA Award and a FAPESP Young Investigator Award to DB and a NIH grant (CA73756) to AB.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 903. doi:1538-7445.AM2012-903
Abstract 907: The efficiency of Nek2 siRNA for liver metastasis of pancreatic cancer
Authors: Kokuryo Toshio , Yokoyama Yukihiro , Nagino Masato
Published: August 2012

Background: Nek2 (NIMA-related kinase 2) is a member of the serine/threonine kinase family, which related to the essential mitotic regulator NIMA. Nek2 is involved in cell division and mitotic regulation by centrosome splitting. We reported that the efficiency of Nek2 as molecular target for several cancers, such as cholangiocarcinoma, breast cancer and colorectal cancer. Methods: We examined the effect of Nek2 siRNA treatment on the tumor of pancreatic cancer in xenograft mouse model. We also challenged Nek2 siRNA in the liver metastasis model of pancreatic cancer. Results and Discussion: Nek2 siRNA suppressed the growth of tumors in xenograft pancreas cancer model. In liver metastasis model, Nek2 siRNA decreased the number of metastasis and resulted in reduction of metastasis volume. Liver metastasis is one of the major undesirable complications frequently associated with inoperable cases. The Nek2 suppression with siRNA is also effective in the inhibition of liver metastasis of pancreas cancer. Conclusions: Nek2 plays a critical role in tumorigenic growth of various cancers, and inhibition of Nek2 expression with its siRNA causes suppression of cancer growth. Our data provides a strong rationale for the further investigation of Nek2 inhibitors as a new cancer therapy, holding the potential to provide regression of multiple human malignancies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 907. doi:1538-7445.AM2012-907
Abstract 909: ErbB-2 restricts Mib-1 and Jagged-1 association to inhibit Notch-1 activation in ErbB-2 positive breast cancer
Authors: Pandya Kinnari , Osipo Clodia
Published: August 2012

We have recently published that Notch could be an important target in recurrent, or possibly trastuzumab resistant, ErbB-2-positive breast cancer to prevent disease progression. Coincidentally, co-overexpression of Notch-1 ligand, Jagged-1, in breast cancer have been associated with the poorest overall survival. Preliminary results from our lab demonstrated that trastuzumab or lapatinib treatment of SKBr3 cells increased Jagged-1 protein expression by Flow Cytometry. Cell surface biotinylation assays showed that Jagged-1 was enriched on the cell surface in response to trastuzumab treatment and this was mimicked by expression of K44A Dynamin. The precise role of Jagged-1 in ErbB-2-mediated inhibition of Notch-1 is not yet known. The results showed that a combined inhibition of Jagged-1 by siRNA and ErbB-2 by trastuzumab, inhibited cell proliferation and induced apoptosis in 95% of SKBR3 cells. Thus, we asked what is the molecular mechanism by which ErbB-2 inhibits Notch activity. Specifically, ErbB-2 inhibited the association of Mib1, an E3 ubiquitin ligase that is necessary for Notch activation, with Jagged-1 and this was reversed in response to trastuzumab or lapatanib. Recent evidence suggests that ErbB-2 activates PKC∈ and that PKC∈ is critical for ErbB-2-mediated cancer cell invasion. We observed that ErbB-2 increased the amount of PKC∈ found in a complex with Jagged-1. This result suggests that PKC may phosphorylate Jagged-1 or other associated proteins to restrict Jagged-1/Mib1 interaction and thus restrict Notch activation. Interestingly, we identified a substrate of PKC∈ kinase activity, approximately 100 kDa, which was in a complex with Jagged-1 in response to lapatinib treatment. Taken together, these results suggest a possible the role for PKC∈ in ErbB-2-mediated suppression of Notch-1 activity by inhibiting the ability of Jagged-1 to interact with Mib-1.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 909. doi:1538-7445.AM2012-909
Abstract 914: Ciclopirox olamine (CPX) inhibits breast cancer cell proliferation by blocking the formation of a PEAK1-Src-eIF5a protein complex
Authors: Weems Jessica M. , Reno Theresa A. , Klemke Richard L.
Published: August 2012

The antimycotic drug ciclopirox olamine (CPX) is being evaluated in clinical trials as a re-positioned anti-cancer agent. Although low micromolar concentrations of CPX have been shown to inhibit cell proliferation and solid tumor growth in preclinical models, the mechanism of action remains poorly characterized. In the present study, we demonstrated that CPX treatment potently inhibits cell proliferation and protein expression of the novel tyrosine kinase pseudopodium-enriched atypical kinase 1 (PEAK1) in several breast cancer cell lines, whereas forced overexpression of PEAK1 results in decreased sensitivity to CPX treatment and increased proliferation. PEAK1 protein expression modulates Src kinase activity in proliferating cancer cells and is upregulated in a number of human malignancies, but the mechanisms that regulate its expression have not been characterized (PNAS, 107(24), 10920-5). Here we demonstrate that CPX treatment inhibits the hypusination of eukaryotic translation initiation factor 5a (eIF5a), leading to decreased PEAK1 protein expression and Src kinase activity. siRNA knockdown of eIF5a inhibited PEAK1 expression and Src activity. Likewise, inhibition of Src kinase in cancer cells prevented eIF5a and PEAK1 protein expression, indicating that these proteins tightly regulate one another. Further investigation revealed that in breast cancer cells PEAK1, Src, and eIF5a form a complex which is disassociated by CPX treatment. These findings support a model in which PEAK1 amplification in malignant cells promotes increased Src kinase activity thereby leading to increased eIF5a-mediated PEAK1 protein expression levels. Taken together, these data indicate that CPX has significant potential as a repositioned therapeutic to combat PEAK1 and Src driven human cancers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 914. doi:1538-7445.AM2012-914
Abstract 917: AZD2014, a dual mTORC1 and mTORC2 inhibitor is differentiated from allosteric inhibitors of mTORC1 in ER+ breast cancer
Authors: Guichard Sylvie M. , Howard Zoe , Heathcote Dan , Roth Mark , Hughes Gareth , Curwen Jon , Yates James , Logie Armelle , Holt Sarah , Chresta Christine M. , Davies Barry R. , Malagu Karine , Hummersone Marc , Pass Sarah L. , Green Stephen , Pass Martin
Published: August 2012

The mammalian target of rapamycin (mTOR) is a major sensor of nutrients and energy and is part of two multiprotein complexes mTORC1 and mTORC2. mTOR activation is widely reported in cancer and is associated with poor prognosis and resistance to standard of care treatment. Allosteric inhibitors of mTOR such as rapamycin partially inhibit mTORC1 and do not inhibit mTORC2. AZD2014 is a close analogue of AZD8055 and a selective inhibitor of mTOR kinase. AZD2014 has greater inhibitory activity against mTORC1 compared to rapamycin: AZD2014 decreases p4EBP1 Thr37/46, inhibits the translation initiation complex and decreases overall protein synthesis while rapamycin has no effect. AZD2014 also inhibits the mTORC2 biomarkers pAKTSer473 and pNDRG1Thr346. AZD2014 has broad antiproliferative activity across multiple tumour cell lines. In particular, AZD2014 induces growth inhibition and cell death in breast cancer cell lines, including ER+ cell lines with acquired resistance to hormone therapy. In vitro, the potency of AZD2014 is ∼ 5-fold lower compared to AZD8055. However, AZD2014 has improved pharmacokinetics compared to AZD8055. In vivo, AZD2014 induces tumour growth inhibition against several xenograft models including a human primary explant model of ER+ breast cancer refractory to tamoxifen. The antitumour activity is associated with modulation of both mTORC1 and mTORC2 substrates. Overall, AZD2014 is a potent mTOR kinase inhibitor with an in vitro profile comparable to AZD8055 but with improved pharmacokinetic properties over AZD8055. AZD2014 is currently in phase 1 clinical trials.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 917. doi:1538-7445.AM2012-917
Abstract 92: Odonogenic Ameloblast Associated Protein (ODAM) moderates cell growth and invasion in the human breast cancer line MDA-MB-231 in part through the TGF-β signaling pathway
Authors: Phipps Jonathan E. , Foster James S. , Bell John , Solomon Alan , Kestler Daniel P.
Published: August 2012

Breast neoplasms are the second leading cause of cancer deaths of women in the United States. Recently, it has been shown by immunohistochemical staining of tumor biopsy tissue that nuclear localization of the odontogenic ameloblast associated protein (ODAM) correlated with staging and increased survival in patients, leading to the proposal of this protein as a novel biomarker in breast cancer. Further, ectopic expression of recombinant ODAM protein in the invasive breast carcinoma line MDA-MB-231 (231-ODAM) was shown to slow cell growth to 30-50% of that seen in control 231 cells, increase apoptosis, effect developmental change, and decrease the ability of cells to migrate or invade through extracellular matrix in transwell barrier assays. Further, this expression reduced the ability of these cells to form solid tumors by greater than 10-fold in immunodeficient mice, or establish tumor colonization of the lungs after tail vein injection. Herein, we show results of microarray and qRT-PCR data collected from 231-ODAM and control cells revealing effects of ODAM on the expression of a number of genes which have been reported to be affected by or active in the TGF-β pathway including TGF-β I-II, HAS2, Gli-2, SMADs 2, 3 and 7, PLAU and others. This suggests that ODAM interacts in part with the TGF-β pathway. When challenged with neutralizing antibodies to block TGF-β activity we observed an increase in 231-ODAM cell growth which was approximately 80% that of the 231-control line. In addition, antibody blockade of TGF-β signaling restored the ability of 231-ODAM cells to invade and migrate through matrigel-coated barriers to that of the 231-control line. Taken together, these results and others suggest that ODAM acts in part through the TGF-β pathway, which has been implicated with invasion and metastasis in breast cancer and other malignancies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 92. doi:1538-7445.AM2012-92
Abstract 926: Experimental therapy of pancreatic cancer with KCN1, a novel anticancer agent targeting HIF-1α pathway
Authors: Wang Wei , Ao Lin , Zhang Xiangrong , Zhang Xu , Van Meir Erwin G. , Zhang Ruiwen
Published: August 2012

Hypoxia is a major driving force in a majority of human cancers and correlates with a poor outcome of cancer treatment. Hypoxia Inducible Factor-1 (HIF1) has been identified as the key orchestrator of hypoxic response due to its transactivation of genes that are involved in many aspects of malignant tumor growth from cell survival and metabolism to angiogenesis and invasion. Thus, pharmacological targeting of HIF-1 represents a promising strategy to inhibit tumor growth and progression. The purpose of the present study was to determine anti-cancer activity and pharmacological properties of KCN1, a novel small molecule HIF-1α pathway inhibitor. We investigated the in vitro activity of KCN1 on the survival of several human pancreatic cancer cell lines, including HPAC, Panc-1 and BxPC3 cells. KCN1 exerted potent effects against the various cell lines, leading to a significant decrease in cell viability, and inhibited cell proliferation and cell cycle progression, leading to an arrest in the G1 phase. We also found that the expression of numerous proliferation-associated and cell cycle regulatory proteins were affected by KCN1. It reduced the expression of E2F1, Cyclin D1, Cyclin E, Cdc25c and CDK 2, 4, and 6 and, conversely, increased p21 expression. Moreover, KCN1 inhibited the growth of pancreatic cancer xenograft tumors in nude mice. There were no significant host toxicity and no gross organ abnormalities upon necropsy. We also developed an HPLC method for KCN1 quantitation and accomplished experiments to derive preclinical information for its further development. The HPLC method provided a linear detection of KCN1 in biological matrices in the range from 0.1 to 100 μM, and had a limit of quantitation of 0.085 μM in mouse plasma. KCN1 was relatively stable in plasma, being largely intact after an 8-hr incubation in mouse plasma at 37°C. The compound was extensively plasma bound, and was metabolized by S9 microsomal enzymes. Pharmacokinetic studies indicated that KCN1 could be detected in tumors and all of the normal tissues examined. In conclusion, our preclinical data indicate that KCN1 is a potential therapeutic agent for pancreatic cancer. The initial pharmacological data provide a basis for its future development as a preclinical and clinical lead HIF1 inhibitor. (This work was supported by NIH/NCI grant R01 CA116804.)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 926. doi:1538-7445.AM2012-926
Abstract 938: Metabolomic analysis on pharmacological responses to oxaliplatin plus 5-FU in colorectal cancer cells
Authors: Nishimuta Akito , Tsuzaki Junya , Ikoma Yusuke , Otani Yuki , Irie Hidehiro , Suzuki Tetsuya , Sugimoto Masahiro , Soga Tomoyoshi , Tanigawara Yusuke
Published: August 2012

Purpose: Oxaliplatin (L-OHP) in combination with 5-fluorouracil (5-FU)/leucovorin (FOLFOX regimen) is an important treatment of metastatic colorectal cancer. However, metabolic functions to determine pharmacological response to L-OHP in combination with 5-FU are still unclear. The purpose of this study is to elucidate metabolomic responses to L-OHP in combination with 5-FU and key pathways relating to chemosensitivity. Experimental Procedures: Human colorectal carcinoma, HCT116 (high-sensitive) and DLD-1 (low-sensitive) cells, were exposed to L-OHP, 5-FU or L-OHP plus 5-FU. After treatment with the anti-cancer agents, the intracellular metabolites were extracted by liquid-liquid extraction and simultaneously and quantitatively analyzed by capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). The mRNA expression level of spermidine/spermine N1-acetyltransferase (SSAT) was measured by real-time quantitative RT-PCR (Taqman PCR). Results: N1-acetylspermine and N8-acetylspermidine in polyamine metabolism were accumulated to a greater extent after L-OHP exposure in drug-sensitive cancer cells. The mRNA expression level of SSAT-1, a key enzyme in polyamine catabolism, increased after L-OHP exposure in drug-sensitive cancer cells but not drug-resistant cancer cells. In addition to the up-regulation of polyamine metabolism in drug-sensitive cancer cells, the intracellular levels of endogenous nucleotides remarkably increased after L-OHP exposure in drug-sensitive cancer cells. These results imply the changes in nucleotide metabolism due to the disruption of DNA synthesis by L-OHP. The intracellular level of α-alanine also accumulated after L-OHP exposure in drug-sensitive cancer cells. α-alanine is known as a pyrimidine catabolite of uracil. These results show that nucleotide metabolism and polyamine metabolism may be important metabolic pathways relating to L-OHP chemosensitivity. Furthermore, in drug-sensitive cancer cells, polyamine metabolism, glutathione metabolism, and nucleotide metabolism were up-regulated after exposure to L-OHP plus 5-FU. On the other hand, metabolites belonging to each metabolic pathway on the whole increased moderately after exposure to L-OHP plus 5-FU in drug-resistant cancer cells. Conclusions: Polyamine metabolism, glutathione metabolism, and nucleotide metabolism are important metabolic pathways relating to responsiveness to L-OHP plus 5-FU. The present CE-TOFMS metabolome analysis created a new finding on metabolomic response to L-OHP plus 5-FU in colorectal cancer cells with different chemosensitivities.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 938. doi:1538-7445.AM2012-938
Abstract 941: Suppression of the androgen receptor function by c-Jun in prostate cancer via a dual mechanism
Authors: Hsu Chih-Chao , Hu Chang-Deng
Published: August 2012

Androgen receptor (AR) signaling plays a pivotal role in growth and survival of prostate cancer cells. Upon ligand binding, AR translocates into the nucleus and regulates expression of multiple genes through binding their promoter regions. Thus, altered expression and activity of AR contribute to disease progression. Consequently, significant effort has been undertaken to identify and characterize numerous coactivators and corepressors of AR. Here we report that the transcription factor c-Jun, a basic region leucine zipper (bZIP) transcription factor and is an important member of the AP-1 family, acts as a transcriptional repressor to inhibit the AR transcriptional activity. Furthermore, we have found that c-Jun also represses the transcription of AR. Overexpression of c-Jun in LNCaP prostate cancer cells inhibited luciferase reporters driven by the androgen-induced prostate-specific antigen (PSA) promoter, probasin promoter, mouse mammary tumor virus (MMTV) promoter and tandem repeats of androgen response elements in a dose-dependent manner. Conversely, knockdown of c-Jun enhanced androgen-stimulated AR activity in LNCaP cells. To further confirm the results, we generated a doxycycline-inducible c-Jun overexpression LNCaP stable cell line using lentivrial system. Consistent with the results of promoter activity assay, induction of c-Jun by doxycycline inhibited both steady state and androgen-induced PSA mRNA and protein levels. Interestingly, the protein and mRNA of AR were also downregulated when c-Jun was induced, suggesting that c-Jun suppresses AR expression at the transcriptional level. Moreover, c-Jun induction resulted in a significant reduction in cell number, suggesting that c-Jun suppresses LNCaP cell proliferation by antagonizing AR signaling. In summary, our results suggest that c-Jun negatively regulates the AR signaling by a dual mechanism. Future identification of negative regulators of c-Jun expression will provide a new opportunity to develop novel therapeutics.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 941. doi:1538-7445.AM2012-941
Abstract 943: Characterization of RET and integrin signaling in thyroid tumors
Authors: Lian Eric , Cockburn Jessica , Varma Sonal , Kasaian Katayoon , Jones Steven J.M. , Tron Victor , Wiseman Sam , Mulligan Lois
Published: August 2012

The REarranged in Transfection (RET) tyrosine kinase is important during development of neural crest derived tissues such as the enteric and sympathetic nervous systems, but is also activated in multiple human tumour types. Activating mutations of RET play an important role in thyroid cancers including both papillary thyroid carcinoma (PTC) and medullary thyroid carcinoma (MTC). More broadly, recent studies have also shown that RET may be active in other tumour types such as pancreatic and breast cancers, and that the overexpression and activation of RET may be linked to more aggressive disease. In order to explore this link, we have investigated the expression of RET in a large cohort of over 400 thyroid tumour samples of multiple histologies, ranging from benign lesions through to aggressive, metastatic disease by immunhistochemistry using a thyroid tissue microarray. Our data suggest that RET expression may correlate with more aggressive phenotype across a broader spectrum of tumours than previously predicted. We are currently investigating this association further; first by examining the expression of two major RET protein isoforms, RET9 and RET51, in this panel of tumours, and second, by investigating the coexpression of RET with another group of proteins associated with tumour progression, the integrin family. In preliminary studies, we have evaluated RET coexpression with two integrin subunits, ITGB1 and ITGB3. Our data suggest correlation between tumour aggressiveness and coexpression of RET with these integrin subunits. Together, our data provides insight on the role of RET in increasing aggressiveness over a range of tumours.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 943. doi:1538-7445.AM2012-943
Abstract 949: Disruption of growth hormone signaling improves the efficacy of conventional chemotherapy in a rat model of mammary cancer
Authors: Lantvit Daniel D. , Shen Qi , Yang Jilai , Unterman Terry G. , Swanson Steven M.
Published: August 2012

Epidemiological and laboratory based studies suggest that the growth hormone/insulin-like growth factor I (GH/IGF-I) axis is positively correlated with a variety of different cancer types. In recent years, our research team has developed animal models to explore the role of GH signaling in carcinogenesis. These include rat and mouse models of mammary, prostate and colon cancer in which the GH receptor is knocked out, antagonized or GH itself is knocked out. In all of these models, we observed a significant (50% or more) disruption in carcinogenesis when GH signaling is impaired compared to normal controls. Our initial studies demonstrated that carcinogenesis can be effectively inhibited by the disruption of GH signaling in animals lacking genes for wild-type GH or the GH receptor. These findings are consistent with a recent report by Guevara-Aguirre and colleagues (Sci Transl Med 3: 70ra13, 2011) who found that a population lacking a functional GH receptor (Laron syndrome) were cancer free except for one patient whose ovarian cancer did not recur after chemotherapy. A control cohort of relatives suffered a 20% mortality rate from cancer. The response of the Laron patient's tumor to chemotherapy inspired us to hypothesize that the lack of GH signaling may render a tumor more vulnerable to conventional chemotherapy. To test this hypothesis, we treated 6 Spontaneous Dwarf rats (SDR) with GH (150 μg/kg twice daily) beginning at 3 weeks of age; 6 control rats received vehicle injections. At 4 weeks of age, all rats were exposed to a single injection of the mammary carcinogen N-methyl-N-nitrosourea (50 mg/kg). Once a rat developed a mammary tumor of 1cm in diameter, GH or vehicle injections were halted and doxorubicin (1.25 mg/kg; 6 injections over 2 weeks) treatments began. The dose of doxorubicin that was chosen was lower than that normally used to induce regression in this model. We observed that tumor growth in wild-type rats was stopped and remained static during treatment with doxorubicin. In contrast, the tumors of SDR rats, lacking GH, all regressed in response to doxorubicin treatment (p < 0.005). These data suggest that disrupting GH signaling may enhance the efficacy of conventional anticancer chemotherapy. Pegvisomant, a GH antagonist approved by the FDA for the treatment of acromegaly, or one of several investigational drugs currently under study for the disruption of IGF-I signaling, may serve to translate the findings presented here to the clinic to improve current cancer therapy regimens. This work was supported by NIH grant R01-CA099904.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 949. doi:1538-7445.AM2012-949