bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1534: Hes1 regulates hypoxia induced chemoresistance of myeloma cells
Authors: Das Tuhin , Pisklakova Alexandra , Fei Zhaoliang , Nefedova Yulia
Published: August 2012

Bone marrow (BM) microenvironment plays a critical role in response of tumor cells to chemotherapeutic drugs. Hypoxia has been shown to contribute to pathogenesis not only solid but also hematological tumors. While normal BM environment is hypoxic, tumor growth is associated with increased hypoxia in BM niche. We have previously demonstrated that activation of Notch signaling could be one of the mechanisms responsible for survival of multiple myeloma (MM) cells from chemotherapeutic drugs. Here we investigated whether hypoxia could modulate Notch signaling and induce chemoresistance of MM cells. Three MM cell lines were treated with doxorubicin or melphalan in hypoxic (1% O2) or normoxic conditions. Using Annexin V binding assay we demonstrated that hypoxia induced chemoresistance in only one (H929) cell line studied. This effect was associated with significant up-regulation of expression of Notch target gene Hes1 and its protein level while Hes1 level was unchanged in other two MM cell lines. Inhibition of Hes1 with siRNA canceled the protective effect of hypoxia on MM cells. To further confirm the involvement of Notch pathway in regulation of drug sensitivity, Hes-1 was overexpressed in MM cells in normoxic condition using vector pIRES-AcGFP-Hes-1. MM cells with increased Hes1 level became less sensitive to chemotherapeutics as compared to cells transfected with control vector. Hes-1 is considered to be a Notch target gene. However, hypoxia did not affect Notch receptors expression level in MM cells. The effect of hypoxia on Hes1 was Notch-independent as was evident from Notch/CBF1 reporter assay. In addition, inhibition of Notch receptor cleavage with gamma-secretase inhibitor GSI-XII (Calbiochem) did not affect hypoxia induced MM cell chemoresistance. Up-regulation of Hes-1 was induced by HIF-1a as treatment of MM cells with hypoxia mimetic deferoxamine resulted in up-regulation of Hes1 and inhibition of HIF-1a with siRNA abrogated hypoxia-induced protection of MM cells. Thus, our study, for the first time, demonstrates that hypoxia could induce chemoresistance of MM cells through Notch-independent up-regulation of Hes-1. These results could be important not only for understanding the cancer biology but for designing therapeutic intervention in MM.

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 1534. doi:1538-7445.AM2012-1534
Abstract 1539: Antibody targeted CpG for the immunotherapy of solid tumors
Authors: Jang Julie K. , Hu Peisheng , Li Zhongjun , Khawli Leslie A. , Epstein Alan L.
Published: August 2012

A method is described to improve the therapeutic effects of unmethylated CpG oligodeoxynucleotides (ODNs) analogues, which can be used to stimulate the innate immune system for the treatment of cancer. The study is based on the generation of novel reagents that can be used to target tumors after linkage of CpG ODNs analogues to tumor-targeting monoclonal antibodies. This approach is novel in concept and may yield important information regarding the effectiveness of innate immunity in the treatment of cancer. CpG has been used primarily as an adjuvant injected locally at the site of interest or mixed with tumor vaccines. For systemic diseases such as cancer, however, the local administration of CpG would limit its potential to the site of injection. To address this, we have chemically linked active CpG motif analogues to chTNT-3, a monoclonal antibody which targets tumor necrosis, a site rich in tumor antigens. Our findings validate the usefulness of this novel approach and show that, compared to the parental antibody, the CpG immunoconjugate is able to target tumor and produce a 50% greater reduction in tumor growth. It is anticipated that the availability of antibody targeted CpG will enable research to optimize the effectiveness of this approach, especially when combined with other forms of immunotherapy, for the successful treatment of solid tumors. Additional studies using CpG motif analogues conjugated to rituximab (anti-CD20) and trastuzumab (anti-HER2/neu) are underway to demonstrate the full potential of this approach in tumors positive for these common biomarkers.

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 1539. doi:1538-7445.AM2012-1539
Abstract 154: [6]-Shogaol inhibits cell growth and induces apoptosis in non-small-cell lung cancer (NSCLC) cells by regulating multiple targets
Authors: Lee Mee-Hyun , Kim Myoung Ok , Oi Naomi , Bae Ki Beom , Huang Zunnan , Kang Soouk , Xie Hua , Lim Tae-Gyu , Bode Ann M. , Dong Zigang
Published: August 2012

Non-small-cell lung cancer (NSCLC) is the leading cause of cancer mortality worldwide. Despite substantial progress in developing chemotherapeutics for the treatment of NSCLC, primary and secondary resistance limits the success of these therapies. NSCLC cells exhibit different EGFR mutations and EGFR has extensive cross-talk with other cell signaling pathways. Therefore, suppression of the inappropriate expression of multiple targets is considered to be a rational therapeutic and preventive strategy for the management of NSCLC. Our initial molecular-target oriented virtual screening revealed that the ingredients of ginger, including [6]-gingerol, [6]-shogaol and [6]-paradol appeared to be potential candidates for the prevention and therapy of NSCLC cells. Among the three compounds, [6]-shogaol showed the greatest inhibitory effect on growth and soft agar colony formation of NSCLC cells. [6]-Shogaol induced cell cycle arrest (G1 or G2/M) and apoptosis. Furthermore, [6]-shogaol interacted with PI3-K and AKT and inhibited AKT kinase activity. Finally, [6]-shogaol increased the expression of p27, which is one of the target proteins in the AKT signaling pathway. The present results clearly indicate that [6]-shogaol exerted a strong anti-cancer effect and can be regarded as useful tool for the treatment of NSCLC.

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 154. doi:1538-7445.AM2012-154
Abstract 1544: Combined oncolytic virotherapy and immunotherapy for malignant mesothelioma
Authors: Guo Z. Sheng , Zhou Jingjiao , O'Malley Mark E. , Sathaiah Magesh , Bartlett David L.
Published: August 2012

Introduction. Oncolytic viruses have therapeutic potential in cancer by selectively replicating within malignant cells and/or other cells in the tumor tissues, causing cell death. Vaccinia virus (VACV) with deletion of viral genes encoding for thymidine kinase and vaccinia growth factor and armed with a chemokine gene encoding CCL5 (vvDD-CCL5) has been previously shown to be safe and efficacious in a murine colon cancer model (Li J. et al., Mol Ther., 19: 650-7; 2011). Here we explored combination therapy with the use of this armed oncolytic virus and immunotherapy in a murine malignant mesothelioma model in syngeneic BALB/c mice. Methods. The viral replication and oncolysis was examined in murine AB12 mesothelioma cancer cells in vitro, and the combination of oncolytic virus, IL-2 and anti-CD25 and anti-CTLA4 antibodies, was investigated in vivo to treat a murine model of peritoneal malignant mesothelioma (PMM) derived from AB12 cells in BALB/c mice. Results. In vitro, vvCCL5 and its parental virus vvDD replicate well in AB12 cancer cells and lead to efficient cytotoxicity in these cancer cells. In vivo biodistribution analysis indicated that both viruses displayed highly tumor selective replication; however, vvDD-CCL5 replicated to a greater extent and displayed increased persistence in the tumor tissue. As a result, vvDD-CCL5 was more efficient than vvDD, working in a viral dose-dependent manner and leading to increased survival of tumor-bearing mice. Combination therapy of virus with antibodies against CD25 and CTLA4 and IL-2 was investigated. Clearly, this has been the best strategy to treat AB12 PMM, achieving the best long-term survival of mice. We are currently investigating its cellular and molecular mechanisms by this combination leading to tumor regression and long-term survival of mice. Conclusions: The chemokine gene-armed oncolytic virus (vvDD-CCL5) is effective in a PMM tumor model. The combination of this virus with an immunologic regimen of Treg depletion and IL-2 treatment has been demonstrated to be highly efficacious for PMM. Further understanding of its cellular and molecular mechanisms of this treatment strategy will facilitate the optimization of combined therapeutic regimens for PMM.

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 1544. doi:1538-7445.AM2012-1544
Abstract 1546: Combined direct intratumoral adenoviral delivery and production of Rheoswitch®-regulated IL-12 and IFNα enhances antitumor activity in lung and breast cancer models
Authors: Murugesan Selva , Chan Tim , Reed Charles , Bharathan Mini , Connelly Sheila , Fogler William E. , Youssoufian Hagop , Herberman Ron
Published: August 2012

Current cancer immunotherapies have provided limited success in the clinic and innovative strategies are required to further enhance the effectiveness of an anti-tumor immune response.This study assessed anti-tumor activity utilizing intratumoral (i.t.) administration of adenovirus (Ad) with the novel Rheoswitch Therapeutic System®(RTS®), an inducible promoter system, for regulated expression of murine IL-12 or IFNα. Oral administration of a small molecule activator ligand (AL), INXN-1001, regulates the expression of IL-12 in Ad-RTS-mIL-12 and IFNα in Ad-RTS-mIFNα. The regulated expression and therapeutic benefit of IL-12 and IFNα from i.t. administered Ad-RTS-mIL-12 and Ad-RTS-mIFNα, either alone or in combination, was examined in syngeneic Lewis lung carcinoma (LLC) and syngeneic mammary carcinoma (4T1) models. In the LLC model, daily treatment with oral AL alone (administered in feed at 1000 ppm, representing a daily dose of ∼225 mg/kg/day) or i.t. cytokine gene therapy in the absence of AL did not result in significant inhibition of tumor growth compared to control, untreated tumors. In contrast, i.t. injection with 1010 vp Ad-RTS-mIL-12 or Ad-RTS-mIFNα and daily oral AL led to significant tumor growth inhibition by day 25 (72 and 71%, respectively; p<0.05). Notably, combined treatment of the LLC tumors with Ad-RTS-mIL-12 and Ad-RTS-mIFNα with oral AL resulted in significant anti-tumor effect compared to either treatment alone (97% growth inhibition; p<0.05) without overt toxicity as assessed by no change in body weight. In the 4T1 model, i.t. treatment with 1010 vp of Ad-RTS-mIL-12 plus AL or Ad-RTS-mIFNα plus AL led to 58 and 53% inhibition of tumor growth compared to control untreated tumors by day 34 (p<0.05). Notably, concomitant treatment with both Ad-RTS-mIL-12 plus AL and Ad-RTS-mIFNα plus AL resulted in enhanced anti-tumor activity with 80% growth inhibition. These data indicate that the combined treatment strategy using RTS-regulated IL-12 and IFNα in Ad vectors concomitant with AL induces effective therapeutic activity against aggressive murine tumors. Future studies will investigate the mechanism by which both IL-12 and IFNα exert their anti-tumor effect in the above tumor models.

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 1546. doi:1538-7445.AM2012-1546
Abstract 1548: Ultraviolet B-induced platelet-activating factor receptor agonists mediate augmentation of melanoma tumor growth via regulatory T cells: Implication of systemic immunosuppression
Authors: Sahu Ravi P. , Konger Raymond L. , Touloukian Christopher E. , Travers Jeffrey B.
Published: August 2012

Ultraviolet B (UVB)-irradiation to human or mouse skin generates Platelet-activating factor (PAF) and novel oxidatively-modified glycerophosphocholines (Ox-GPCs) with PAF-receptor (PAF-R) agonistic activity. These lipids mediate systemic immunosuppression in a process involving IL-10. The current studies sought to determine the functional significance of UVB-mediated systemic immunosuppression in an established model of murine melanoma progression. As our studies demonstrated that B16F10 tumors do not express functional PAF-Rs, retroviral-mediated transduction of the PAF-R was used to create PAF-R-positive B16F10 melanoma tumor cells. We show that UVB irradiation augments B16F10 tumor growth and is dependent on host, but not melanoma cell, PAF-R-expression as UVB or the PAF-R agonist, carbamoyl- PAF (CPAF), both promote B16F10 tumor growth in wild-type mice, independent of whether B16F10 cells express PAF-Rs, but do not augment tumor growth in PAF-R deficient (Pafr -/-) mice. Systemic antioxidant treatment ameliorated UVB-mediated augmentation of tumor growth, indicating involvement of Ox-GPC PAF-R agonists produced non-enzymatically. Host immune cells are required as CPAF-induced augmentation of tumor growth is not seen in immunodeficient NOD SCID mice. Finally, depleting antibodies against IL-10 in WT mice, or depletion of CD25-positive cells (suggestive of FoxP3 directed regulatory T cells) in FoxP3EGFP transgenic mice block UVB/CPAF-induced tumor growth, supporting a requirement for IL-10 and regulatory T cells (Tregs) in this process. These findings indicate that UVB-generated Ox-GPCs with PAF-R agonistic activity enhance experimental murine melanoma tumor growth through targeting host immune cells, most notably Tregs, to mediate systemic immunosuppression. These studies describe a previously unrecognized mechanism by which melanoma tumor cells can escape antitumor immunity. Inasmuch as other pro-oxidative stressors could potentially generate PAF-R agonists, this pathway could have clinical relevance in terms of devising better strategy for melanoma immunotherapy.

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 1548. doi:1538-7445.AM2012-1548
Abstract 1554: Rosiglitazone and Gemcitabine combination therapy reduces immune suppression and modulates T cell populations in pancreatic cancer
Authors: Bunt Stephanie K. , Mohr Ashley M. , Bailey Jennifer M. , Grandgenett Paul M. , Hollingsworth Michael A.
Published: August 2012

Pancreatic ductal adenocarcinoma (PDA) is a leading cause of cancer mortality with a dismal 2-5% 5-year survival rate. Monotherapy with Gemcitabine has limited success, highlighting the need for additional therapies that enhance the efficacy of current treatments. We evaluated the combination of Gemcitabine and Rosiglitazone Maleate, an FDA-approved drug for the treatment of type II diabetes, in an immunocompetent transplantable mouse model of pancreatic cancer. Tumor progression, survival and metastases were evaluated in mice with subcutaneous or orthotopic pancreatic tumors treated with Pioglitazone, Rosiglitazone, Gemcitabine or combinations of these. We characterized the impact of high dose Rosiglitazone and Gemcitabine therapy on immune suppressive mediators, including MDSC and T regulatory cells, and on modulation of peripheral and intra-tumoral T cell populations. Combinations of Rosiglitazone and Gemcitabine significantly reduced tumor progression and metastases, enhanced apoptosis, and significantly extended overall survival compared to Gemcitabine alone. Rosiglitazone altered tumor-associated immune suppressive mediators by limiting early MDSC accumulation and intra-tumoral T regulatory cells. Combination therapy with Rosiglitazone and Gemcitabine modulated T cell populations by enhancing circulating CD8+ T cells and intra-tumoral CD4+ and CD8+ T cells while limiting T regulatory cells. The results suggest that Rosiglitazone, in combination with Gemcitabine, decreases immune suppressive mechanisms in immunocompetent animals and provide pre-clinical data in support of combining Rosiglitazone and Gemcitabine as a clinical therapy for pancreatic cancer.

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 1554. doi:1538-7445.AM2012-1554
Abstract 1808: HM-032, a novel PI3K/mTOR dual inhibitor, is active on K-Ras/Raf mutation tumors through up-regulation of Bim
Authors: Cui Yumin , Zhang Weihan , Ren Yongxin , Guo Mingchuan , Long Jingwen , Zhou Enkun , Sai Yang , Wang Jian , Yan James , Li Jia , Qing Weiguo , Su Weiguo
Published: August 2012

PIK3CA gene amplification and mutations have been identified in many types of tumors, suggesting the deregulation of PI3K/AKT/mTOR axis plays pivotal roles in tumorigenesis and development. K-Ras/Raf mutation is recognized as one of the key drug resistant factors for tumors against TKIs. HM-032 was reported here as a potent, selective and reversible ATP-competitive PI3K/mTOR dual inhibitor with special apoptotic activity in tumor cells harboring K-Ras mutations. HM-032 showed potent kinase inhibition with IC50 of 0.0008, 0.002, 0.001, 0.002 and 0.001 µM on PI3Kα, β, δ, ≤ and mTOR, respectively. In human prostate PC3 cells, it inhibited p-AKTS473, p-S6 and p-4EPB1 with IC50s of 0.002, 0.015 and 0.056 μM. Of the 89 tumor cell lines from lung, colon, breast, ovarian, and other tumor types, it was found that tumor cells with HER2 gene amplification, or PIK3CA mutation were relatively more sensitive to HM-032. Attractively, HM-032 showed apoptotic induction activity in the tumor cells harboring Ras/Raf mutations through inhibiting p-Erk and increasing gene expression of pro-apoptotic protein Bim. This result suggested that HM-032 might bring benefits to patients carrying K-Ras/Raf mutations in the clinic. Consistent with in vitro studies, HM-032 exhibited significant tumor growth inhibition in a dose dependent manner on multiple human xenograft models, including breast tumor MDA-MB-361(PIK3CAE545K, Her2 amplification), lung tumors H460 (PIK3CAE545K, K-RasQ61H) and A549 (LKB1 del, K-RasG12S), and glioblastoma U87MG (PTEN del) after 3 weeks oral dosing. Correspondingly, decrease of p-AKT and p-S6 was observed in the tumor xenograft tissues upon treatment with HM-032. In addition, HM-032 exhibited unique in vivo PK properties characterized by low clearance and long t1/2, which supported the intermittent dosing schedule in xenograft models. Based on the pre-clinical study results, HM-032 is anticipated to be a promising agent against solid tumors including carrying Ras/Raf mutations.

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 1808. doi:1538-7445.AM2012-1808
Abstract 1810: Mechanistic studies of the dual Akt and JNK inhibitor Chaetoglobosin K: Effect on downstream pathways and AP-1 proteins in tumorigenic cells
Authors: Ali Amna , Matesic Diane F.
Published: August 2012

We have previously shown that the anti-tumorigenic indolylcytochalasin Chaetoglobosin K (ChK) concomitantly down-regulates Akt and JNK activation in ras-transformed cells. This dual inhibition was found not be regulated by Rac1, a Rho protein that is involved in both signaling pathways, or MKK4, an upstream kinase of JNK. The purpose of this study was to determine: 1) the effect of ChK on the activation of downstream mediators of the PI3K/Akt (including mdm2), and JNK (including the activator protein-1 (AP-1) proteins and stat3) signaling pathways; 2) whether the upstream mitogen-activated protein kinase kinase 7 (MKK7) is involved in ChK's effect on JNK. The AP-1 transcription factor complex, composed of proteins of the JUN, FOS, and ATF families, has become a promising therapeutic target due to the proposed role of AP-1 activation in tumorigenesis. In these studies, ras-transformed rat liver epithelial cells were grown to confluence and treated with either ChK (5μM or 10μM) or vehicle (DMSO) for 24 hours. Cell proteins were extracted and separated using SDS-PAGE. Western blot analysis was performed using phosphorylation site-specific antibodies to monitor changes in MKK7, c-JUN, ATF-2, mdm2, and stat3 protein activation levels. The results of these studies indicate that ChK treatment decreased c-JUN and ATF-2 phosphorylation, but had no effect on stat3 phosphorylation. Additionally, ChK treatment decreased mdm2 phosphorylation. ChK did not alter MKK7 activation levels and, taking into consideration its lack of effect on MKK4, suggest ChK does not inhibit JNK via its archetypical MAPK signaling pathway. These studies indicate ChK may serve as a small molecule inhibitor of the AP-1 pathway proteins, as well as the Akt/mdm2 pathway. This data further supports ChK's potential as a unique targeted tumor therapy. This project was funded by NIH grant 1R15CA135415

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 1810. doi:1538-7445.AM2012-1810
Abstract 1822: Novel potent inhibitor of Bcr-Abl mutated imatinib resistant chronic myeloid leukemia cell lines
Authors: Joshi Kalpana S. , Manohar Sonal , Jalota-Badhwar Archana , Sonawane Vinay , Damre Anagha , Sivakumar Meenakshi , Sharma Somesh
Published: August 2012

The hallmark of chronic myeloid leukemia (CML) is the presence of Bcr-Abl oncoprotein that is essential for leukemogenesis and accumulation of neoplastic cells. The Abl tyrosine kinase inhibitor imatinib mesylate (Gleevec) represents the standard treatment for CML. However, a number of CML patients develop imatinib resistance and several mechanisms of resistance have been described. While most mutant forms are sensitive to second-generation tyrosine kinase inhibitors, the T315I mutation remains completely refractory to imatinib, as well as to these agents. Treatment of CML patients harboring T315I mutation is still an unmet medical need in the imatinib and post-imatinib era. We have identified P2745, a novel orally bioavailable small molecule that is effective in imatinib resistant mutations and particularly T315I mutation form to address this unmet medical need. In vitro P2745 showed potent cytotoxicity (IC50 0.8-5 μM) in twelve Bcr-Abl mutated imatinib resistant cell lines including T315I compared to wild type Bcr-Abl cell lines. P2745 did not show cytotoxicity upto 30 μM in normal fibroblasts (MRC-5 and WI-38) and normal human peripheral blood mononuclear cells thus indicating specificity towards cancerous cells. P2745 inhibited pCrkLTyr207 in imatinib-resistant CML cell lines accompanied with down regulation of Bcr-Abl protein levels. Additionally, it up regulated tumor suppressor protein SMAR-1 which resulted in negative regulation TGF-β/SMAD-dependent pathway as demonstrated by low phosphorylated levels of SMAD2 and SMAD3, two key players implicated in the preservation of the malignant progenitor population, and partly responsible for the resistance to treatments targeting Bcr-Abl. P2745 also induced significant apoptosis in imatinib resistant cell lines (Y253F, T315I and E255V) but not in normal MRC-5 cell line. In addition, like imatinib it induced 80-90 % apoptosis in cells derived from CML patients. In vivo studies demonstrated significant (p<0.001), dose dependent efficacy in imatinib resistant T315I cells xenograft in SCID mice. It also demonstrated significant in vivo efficacy in Bcr-Abl wild type imatinib sensitive K-562 (p<0.05) and Ba/F3 (p<0.001) xenografts in SCID mice. PK-PD evaluation in imatinib resistant xenograft experiments indicated that at the efficacious dose, P2745 modulated proteins responsible for CML pathogenesis (60-80 %), which correlates with the levels of P2745 in the tumors. This unique mechanism of action makes P2745 a promising clinical candidate for CML patients harboring T315I mutation.

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 1822. doi:1538-7445.AM2012-1822
Abstract 1834: Targeting ABC transporters in cancer through small molecule inhibitors
Authors: Huynh Tony , Tivnan Amanda , Munoz Marcia , Cheung Leanna , Vishvanath Anasuya , Flemming Claudia , Watt Fujiko , Burkhart Catherine , Gudkov Andrei , Fletcher Jamie , Henderson Michelle , Norris Murray , Haber Michelle
Published: August 2012

Multidrug resistance is one of the major causes of treatment failure in cancer therapy. While multidrug transporter proteins are known for their contributions to chemoresistance and efflux of anti-cancer drugs from cancer cells, a significant body of evidence points to their fundamental roles in tumour biology (Fletcher et al, Nature Rev Cancer, 10:147-156, 2010). We have investigated the ABCC subfamily of multidrug transporter genes in the highly malignant and aggressive childhood solid tumour, neuroblastoma and found that high levels of ABCC1 and ABCC4 are powerful independent prognostic indicators of clinical outcome. However, the agents used to treat the patients described in these studies are not known substrates of ABCC4 and we have shown that siRNA-mediated knockdown of ABCC4 results in reduced proliferation and enhanced morphological differentiation of neuroblastoma cells, in the absence of any cytotoxic drug treatment (Henderson et al, JNCI, 103;1-16, 2011). The aim of this study is to develop a potential new approach for the treatment of neuroblastoma through the inhibition of ABCC4 using small molecule inhibitors. A cell-based screen of a library of diverse chemical small molecules was used to isolate potent small molecule inhibitors of ABCC4 that were able to sensitize HEK293 cells over-expressing MRP4 to a cytotoxic MRP4 substrate, 6-mercaptopurine (6MP). Filtering of compounds based upon their ability to cause 6MP accumulation, together with focused library screening, have resulted in the identification of several chemical structures able to specifically block MRP4. In addition to reversing drug resistance to 6MP, these compounds cause morphological differentiation and inhibition of cell growth, as seen with MRP4 siRNA, in the BE2C neuroblastoma cell line. Importantly, these compounds significantly potentiate morphological differentiation caused by the established differentiation agent, all-trans retinoic acid. We further show that these inhibitors have potency in other MRP4 expressing cancer cell lines beyond neuroblastoma. These pharmacological inhibitors offer clinical potential for the treatment of neuroblastoma and other MRP4 overexpressing 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 1834. doi:1538-7445.AM2012-1834
Abstract 1838: Efficacy of ribonuclease QBI-139 in combination with standard of care therapies
Authors: Strong Laura E. , Kink John A. , Pensinger Daniel , Mei Baigen , Shahan Mark , Raines Ronald T.
Published: August 2012

RNA has been recognized as a drug target for cancer therapy, as evidenced by the ongoing clinical trials of RNAi and antisense therapies. An alternative approach that circumvents the delivery and stability issues of those drugs is to harness the activity of naturally occurring RNA degradation enzymes. Human ribonuclease (RNase) variants have been generated with diminished binding to their natural inhibitor inside cells, which allows the new proteins to kill cancer cells. One of these RNase variants, referred to as QBI-139, demonstrated efficacy against multiple tumor types in xenograft models of human cancer and was selected for an ongoing first in human Phase I clinical trial. Non-small cell lung and ovarian cancer are two of the indications where QBI-139 has shown significant efficacy as a single agent in xenograft models. In planning for the next stage of clinical trials, the impact of combinations of QBI-139 plus standard of care agents in these diseases was determined both in vitro and in vivo. QBI-139 showed additive and synergistic activity in combination with cisplatin and docetaxel, which are standard of care for non-small cell lung and ovarian cancer, respectively. Fixed ratios of QBI-139 and the combination drug based on their EC50 values were tested. The Combination Index (CI) was determined using median effect analysis. Synergy was demonstrated with QBI-139 in combination with cisplatin against non-small cell lung cancer (A549 and H1975). An additive effect of QBI-139 and cisplatin was seen in ovarian (Ovcar-3) cancer. In ovarian cancer (SK-OV-3), a combination of docetaxel and QBI-139 was synergistic with QBI-139. The benefit of the combinations were repeated in xenograft models of both cancers and were signifcat relative to each agent alone. Non-small cell lung and ovarian cancer represent critical unmet needs and new, differentiated treatment approaches such as QBI-139 combination therapy are critical.

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 1838. doi:1538-7445.AM2012-1838
Abstract 1839: Phosphodiesterase 4 regulates lung tumor growth through HIF regulation, proliferation, and angiogenesis
Authors: Savai Rajkumar , Pullamsetti Soni Savai , Schmall Anja , Pomagruk Dawid , Hänze Jörg , Kolosionek Ewa , Wilhelm Jochen , Seeger Werner , Grimminger Friedrich , Schermuly Ralph Theo , Banat Gamal Andre
Published: August 2012

Lung cancer is the leading cause of cancer death worldwide. Recent data suggest that cyclic nucleotide phosphodiesterases (PDEs) are relevant in various cancer pathologies. Here, we elucidate the pathophysiological role of PDE4 and its therapeutic prospects in lung cancer. We exposed 10 different non-small cell lung cancer cell lines (adenocarcinoma, squamous, and large cell carcinoma) to hypoxia and assessed the expression and activity of PDE4 by quantitative real-time PCR, immunocytochemistry, western blotting, and PDE activity assays. Expression and activity of distinct PDE4 isoforms (PDE4A and PDE4D) increased in response to hypoxia in eight of the studied cell lines. Furthermore, we determined various potential hypoxia-responsive elements (HRE) in PDE4A and PDE4D. Silencing of hypoxia-inducible factor subunits (HIF1A and HIF2) by siRNA reduced hypoxic induction of PDE4A and PDE4D. Vice versa, using a PDE4 inhibitor (PDE4i), a cAMP-elevating agent, cAMP analogs, PKA activator/inhibitor, and EPAC activator, we demonstrated that PDE4-cAMP-PKA/EPAC axis regulates HIF signaling as measured by HRE reporter gene assay and expression of HIF target genes (LDHA, PDK1, VEGFA). Notably, PDE4i or PDE4A-/PDE4D-selective siRNA reduced human lung tumor cell proliferation in vitro and colony formation and altered the expression of cell-cycle regulators. Moreover, PDE4i treatment reduced hypoxia-induced VEGF secretion in human cells. In vivo, PDE4i inhibited tumor xenograft growth in athymic nude mice by altering proliferation and angiogenesis. Collectively, our findings suggest that PDE4 is overexpressed in lung cancer, exerts crosstalk with HIF pathways, and promotes lung cancer progression; thus, PDE4 may represent a therapeutic target for lung cancer therapy.

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 1839. doi:1538-7445.AM2012-1839
Abstract 1860: Protective effect of catechol-O-methyltransferase-mediated 4-hydroxyestradiol metabolism in human renal cell cancers
Authors: Chang Inik , Liu Jan , Majid Shahana , Saini Sharanjot , Zaman Mohd S. , Yamamura Soichiro , Shahryari Vary , Chiyomaru Takeshi , Deng Guoren , Dahiya Rajvir , Tanaka Yuichiro
Published: August 2012

Long-term exposure to estrogen and its metabolites may play an important role in renal cell carcinogenesis. Catechol-O-methyltransferase (COMT) participates in the estrogen metabolism pathway by neutralizing toxic substances. Although reduced COMT activity has been suggested to be a risk factor for estrogen-associated cancers, no studies have investigated the biological significance of COMT in the pathogenesis of human renal cell cancers (RCC). Using quantitative PCR, Western blotting and immunohistochemical staining, we initially found that COMT levels are significantly decreased in human RCC tissues and cells suggesting a suppressive role of COMT in tumor development. However, transient over-expression of COMT has no effect on the proliferation, apoptosis and cell cycle progression of RCC cell lines. In contrast, when cells over-expressing COMT are treated with its substrate 4-hydroxyestradiol (4-OHE2), growth is inhibited by apoptotic cell death. We also found that COMT over-expression combined with 4-OHE2 induces up-regulation of growth arrest- and DNA damage-inducible protein ≤ (GADD45α). We further show that down-regulation of GADD45α by a siRNA-mediated approach inhibits cell death, indicating the essential role of GADD45α in the underlying mechanism of COMT action in response to 4-OHE2. Finally, 4-methoxyestradiol (4-ME) fully reproduces the anti-proliferative function of COMT with 4-OHE2 by promoting GADD45α induction. Together, our study shows that COMT in the presence of 4-OHE2 prevents RCC cell proliferation by enhancing apoptosis, and that GADD45α plays a critical role in the COMT-mediated inhibition of RCC. These findings will provide new direction for the biomarker detection and corresponding treatment in the prevention of human RCC.

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 1860. doi:1538-7445.AM2012-1860
Abstract 1871: Role of CYP1B1 gene polymorphisms in anticancer drug cytotoxicity as studied on isogenic cell lines
Authors: Morvan Valérie Le , Richard Elodie , Bellott Ricardo , Pasquies Alban , Robert Jacques , Lansiaux Amélie
Published: August 2012

Cytochrome P450 1B1 (CYP1B1) is found in tumour tissue and is suspected to play a role in oncogenesis and drug resistance. CYP1B1 gene polymorphisms have been associated with the risk of developing lung and other cancers. We have recently shown that one of them (rs1056836, 1697C>G, L432V) was significantly associated with the cytotoxicity of DNA-damaging anticancer drugs in two independent panels of tumour cell lines, the NCI-60 panel and the JFCR-45 panel (Mol Cancer Ther 2010; 9: 3315-21). The present study was aimed at identifying the molecular mechanisms involved in anticancer drug resistance associated with this polymorphic variation. We have cloned the wild-type human CYP1B1 cDNA (1697C) in a lentiviral vector pDesti-pGK and obtained the variant cDNA (1697G) by directed mutagenesis. The two polymorphic variants were then used for the generation of viruses and the infection of cell lines. The CYP1B1 viruses were produced by cotransfection of 293T cells with viral plasmid DNA and either pER51CYP1B1WT-pGK or pER51CYP1B1VAR-pGK plasmid DNA in the presence of calcium phosphate. Cell supernatants containing the virus were harvested 24 h after transfection, filtered through a 0.45 μm membrane and stored at −80°C. Five different cell lines devoid of CYP1B1 expression were infected (COS-1 [Fibroblastic cell line], SW620 [colorectal cancer cell line], CAL27, CAL33 and SQ20B [HNSCC cell lines]). We thus generated five pairs of isogenic cell lines differing only by the polymorphic status of one nucleotide in the CYP1B1 gene. mRNA and protein expression were evaluated by qRT-PCR and western blotting, respectively. The cytotoxicity of a panel of anticancer drugs was evaluated on these cell lines (cisplatin, oxaliplatin, gemcitabine, doxorubicin, etoposide, camptothecin, irinotecan and its active metabolite [SN38]). A systematically higher IC50 was noticed for the cell lines harbouring the variant cDNA as compared to those harbouring the wild-type cDNA, the variant cell lines being 2-3-fold resistant to all agents. These results obtained on isogenic cell lines were in perfect agreement with what could be expected from the study of the cell line panels. The catalytic activity of the two CYP1B1 variants is being studied using ethoxyresorufine O-deethylation. A population of 125 head-and-neck cancer patients treated by chemotherapy in the palliative setting has been prospectively constituted and will be used for the clinical validation of the interest of CYP1B1 genotyping for predicting anticancer drug activity.

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 1871. doi:1538-7445.AM2012-1871
Abstract 1895: The role of autophagy and Atg3 in erlotinib-resistant lung cancer and synergistic cell death with combination of erlotinib and cisplatin
Authors: Lee Jasmine G. , Wu Reen
Published: August 2012

Objective: Erlotinib is a mainstay anti-cancer agent for non-small-cell lung cancer (NSCLC) but resistance to erlotinib is a major problem, clinically. The combination of cisplatin and erlotinib has been suggested to inhibit tumor growth more effectively than a single drug alone in sensitive NSCLC. However, the mechanism underlying this finding remains unclear. The specific role of autophagy in cancer and chemotherapy resistance continues to be unclear (promotion vs. prevention of cancer). In this study, we investigate whether combination low dose erlotinib and cisplatin is effective against erlotinib resistant NSCLC and examined the role of autophagy in erlotinib resistance. Methods: PC9, a NSCLC cell line, was used to develop erlotinib resistant PC9 cells (PC9ER). Cell survival was quantified with Alamar blue assay. LC3II and regulatory proteins of autophagy were measured by western blot. Small interfering RNA (siRNA) transfection was used to block translation of protein of interest. Results: Combination low dose erlotinib and cisplatin resulted in synergistic cell death in PC9ER cells (p<0.0001) and a significant decrease in autophagy (p=0.011). At baseline, there was a significantly higher level of LC3II in PC9ER cells compared to sensitive PC9 (p=0.030) suggesting autophagy may play a role in resistance. Rapamycin significantly increased ER (p=0.0004) and 3-MA significantly sensitized PC9ER cells to treatment (p=0.037). Upon examination of autophagy regulatory proteins between PC9ER and PC9 cells, there was significantly lower levels in p-mTOR (p=0.021) and higher levels of Atg3 in PC9ER at baseline (p=0.018). Among the four treatment groups (control, erlotinib-alone, cisplatin-alone, and erlotinib-cisplatin combination), there was a specific decrease in Atg3 with combination treatment (p=0.005). siRNA transfection of Atg3 resulted in the reversal of ER: 42% more cell death with erlotinib-alone (p<0.0001), 18% more cell death (p=0.002) in cisplatin treatment, and 9% more cell death in erlotinib-cisplatin combination (p=0.047) compared to the counterpart treatment groups without siRNA transfection. Conclusions: Our data may suggest that autophagy may promote cancer survival and ER in NSCLC, specifically by up regulation of Atg3 and targeting of Atg3 may be the key to re-sensitizing erlotinib resistant cancers. In addition, it seems erlotinib-cisplatin combination is an effective therapy by down modulation of autophagy by targeting Atg3. Future pharmacologic therapies specifically targeting Atg3 in complement to erlotinib therapy may be effective in preventing and treating ER.

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 1895. doi:1538-7445.AM2012-1895
Abstract 191: Subclassification of oral cancers using a miRNA-based combinatorial approach
Authors: Jung Hyun Min , Patel Rushi S. , Cohen Donald M. , Jakymiw Andrew , Kong William W. , Cheng Jin Q. , Chan Edward KL
Published: August 2012

The majority of gene expression profiling studies in cancer research is based on comparison of normal against cancerous tissues. Although these comparisons identify general mechanisms underlying certain cancer types, the heterogeneity of tumors contributes to challenges in the interpretation of results. In this study, Agilent human miRNA microarrays were used to analyze 3 normal tongue tissues and 17 oral squamous cell carcinomas (OSCC) extracted from tongue tumors to identify deregulated miRNAs. Our results showed that miRNA expression pattern provided more precise information when cancers are subcategorized based on clinicopathological parameters. Combinatorial analyses using 4 different parameters (tumor primary site, tumor stage, histological subtype, and human papillomavirus 16 status) revealed OSCC subtypes with specific expressions of selected miRNAs. Nine significantly upregulated miRNAs (miR-424, miR-15b, miR-196a, miR-21, miR-155, miR-9*, miR-9, miR-7-1*, and miR-7) and one downregulated miRNA (miR-486-5p) were applied for this analysis. Our study demonstrated the combine use of several miRNAs with multiple clinicopathological parameters could subcategorize these oral cancers. Kaplan-Meier survival analyses showed that advanced tumor stage (hazard ratio = 3.36; 95% confidence interval, 1.08-10.49; p = 0.037), and/or keratinization status (hazard ratio = 3.34; 95% confidence interval, 1.10-10.12; p = 0.033) are related to poor prognosis of oral cancer patients. Interestingly, all the tumors highly expressing miR-21 were keratinized tumors and the corresponding patients had poor survival rate < 30 months after diagnosis ((hazard ratio = 12.46; 95% confidence interval, 2.57-60.32; p = 0.0017) indicating the prognostic importance of miR-21. The expression of the specific miRNAs (miR-21, miR-424, miR-7, miR-7-1*, and miR-155) overexpressed in the keratinizing tumors was significantly correlated to each other (0.438 < r < 0.615, p < 0.041). In silico target prediction analyses using multiple bioinformatics tools identified candidate genes containing multiple binding sites for these miRNAs. The miRNA signatures are indicators for cancer diagnostics, prognostics, and therapeutics and may lead eventually to individualized clinical 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 191. doi:1538-7445.AM2012-191
Abstract 1918: Anti-metastasis effect of EW-7197, a novel ALK5 inhibitor in both breast cancer cells in vitro and mouse model in vivo
Authors: Kim Seung W. , Kim Sol J. , Park Sang A. , Kim Min J. , Kim Dae-Kee , Sheen Yhun Y.
Published: August 2012

We have synthesized new ALK5 inhibitor, EW-7197 and investigated their effects of on breast cancer cells as well as tumor bearing MMTV/cNeu transgenic mouse, 4T1 or 4T1-Luc cell-orthotopic implanted mouse models. The level of ß-casein or the number of metastatic nodule in the lung of the breast tumor bearing MMTV/cNeu transgenic mice or 4T1 cell-orthotopic implanted mice, respectively, were decreased by EW-7197 treatment. The treatment of the EW-7197 also inhibited the luciferase activity in the lung of 4T1-Luc cell-orthotopic implanted mouse compared to that of untreated animal. The levels of MMP2 and MMP9 were decreased in the lung and breast tumor of the EW-7197 treated mice. To determine the inhibitory effect of EW-7197 on TGF-β1-induced transcriptional activation, we performed luciferase reporter gene assay in breast cancer cells. EW-7197 effectively blocked TGF-β1-induced luciferase activity in the cells in a dose-dependent manner. TGFß signaling, the phosphorylation of smad2/3 was decreased by EW-7197. TGFß-stimulated mesenchymal markers of epithelial mesenchymal transition (EMT) were inhibited by ALK5 inhibitor concomitant treatment. Furthermore, EW-7197 rescued TGF-β-induced loss of E-cadherin in NMuMG cells. And also, EW-7197 showed higher inhibition on cell motility and cell invasion based on wound healing assay or invasion assay than SB-505124 and LY-2157299. In summary, EW-7197 have anti-metastatic effect on breast cancer cells in vitro as well as breast cancer models in vivo. This data strongly argue that the ALK5 inhibitor have anti-metastasis effects via inhibiting ALK5 activity in vivo and in vitro.

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 1918. doi:1538-7445.AM2012-1918