bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5553: Development of novel selenium-NSAIDs as potential cancer therapeutics.
Authors: Plano Daniel , Karelia Deepkamal , Pandey Manoj , Amin Shantu , Sharma Arun K.
Published: August 2014

Several non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to be effective chemopreventive agents in both pre-clinical and clinical studies on various cancer types. Here in, we developed several selenium (Se)-NSAID hybrid molecules and evaluated their efficacy as cancer therapeutics. The rationale for introducing Se into the NSAIDs is that this redox-active trace element is an essential micronutrient and a normal component of diets with chemopreventive and anticancer properties. Our recent studies have also shown that appropriately designed organoselenium compounds exhibited promising anti-tumor properties in various preclinical cancer models. We hypothesized that the rational incorporation of Se into NSAIDs should enhance their anti-cancer properties and therefore, we synthesized 16 novel Se-NSAID hybrid agents designed by incorporating Se moieties into the structures of aspirin, ibuprofen, and naproxen. In the first phase, a selenocyanate moiety was incorporated to these NSAIDs and screened for their cytotoxicity in various cancer cell lines. The cell viability results at 24 and 48 h showed that the introduction of this Se functionality on aspirin scaffold achieved a dramatic increase in the activity as compared to aspirin, as well as other NSAIDs or their Se hybrids. Thus, we continued optimization of aspirin with a variety of Se moieties, such as selenides and selenomethyl functionalities. Most of these compounds reduced cell viability in a dose dependent manner, while aspirin had no significant effect. Based on these studies we identified two Se-aspirin hybrid compounds; ASD-43, having a selenide functionality and ASD-49, with a selenocyanate functionality, as the most potent compounds for further development. The IC50 values after 48 h treatment in HCT116 cells were 2.5μM and 1.0 μM and in MiaPaCa-2 cells were 5.0 μM and 2.5 μM for ASD-43 and ASD-49, respectively. To further establish the cytotoxic potential of these compounds, an esterase staining (live and dead) assay was performed in colon (HCT116) and pancreatic (MiaPaCa-2) cancer cells. Treatment of ASD-43 and ASD-49 reduced cell viabilities dose dependently in both HCT116 and MiaPaCa-2 cells, while aspirin had no significant effects. In addition, both these compounds induced caspase-mediated PARP cleavage as early as 24 h in HCT116 cells. In conclusion, new Se-NSAID hybrid agents have been developed which showed a solid potential to be effective cancer therapeutics in our initial studies. Detailed results of these investigations will be presented.

Citation Format: Daniel Plano, Deepkamal Karelia, Manoj Pandey, Shantu Amin, Arun K. Sharma. Development of novel selenium-NSAIDs as potential cancer therapeutics. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5553. doi:10.1158/1538-7445.AM2013-5553
Abstract 5557: BoxA and ethyl pyruvate offer novel therapeutic approaches for human malignant mesothelioma.
Authors: Jube Sandro L. , Rivera Zeyana , Casalgrandi Maura , Bianchi Marco , Pass Harvey I. , Gaudino Giovanni , Carbone Michele , Yang Haining
Published: August 2014

Human malignant mesothelioma (MM) is an aggressive and highly lethal cancer that has been linked to asbestos and erionite exposure. MM causes about 3,000 deaths per year in the US and more than 100,000 deaths per year worldwide. We previously found that the damage-associated molecular pattern (DAMP) high-mobility group box-1 protein (HMGB1) plays a critical role in the early carcinogenic events in MM development by inducing tumor necrosis factor-alpha (TNF-α) secretion, potentiating survival of fiber-exposed primary human mesothelial cells (HM) and enabling HM malignant transformation. We recently showed that HMGB1 is upregulated in MM tumor tissues and cell lines and its levels to be significantly higher in the blood of MM patients compared to healthy individuals. Moreover, MM cells are “addicted” to HMGB1 and HMGB1 promotes proliferation, viability, motility and invasiveness of MM cells. Here we show that the use of the HMGB1 antagonists BoxA or ethyl pyruvate (EP) inhibit the motility, survival and progression of MM cells in vitro and reduce the growth of MM xenografts in SCID mice. BoxA is a fragment of HMGB1 protein that corresponds to the one of the two highly conserved DNA binding domains, and behaves as a competitive inhibitor. EP is the ethyl ester of pyruvic acid, is known to suppress oxygen radical formation, and suppresses HMGB1 secretion. Both BoxA and EP have been shown to down-regulate the activation of the proinflammatory transcription factor, NF-κB, as well as the expression of several proinflammatory proteins, such as TNF-α, IL-6, and HMGB1 itself. Taken together, our results provide a preclinical proof-of-principle that inhibition of HMGB1 activity using either BoxA or EP is sufficient to elicit therapeutic activity, offering novel therapeutic approaches for MM treatment.

Citation Format: Sandro L. Jube, Zeyana Rivera, Maura Casalgrandi, Marco Bianchi, Harvey I. Pass, Giovanni Gaudino, Michele Carbone, Haining Yang. BoxA and ethyl pyruvate offer novel therapeutic approaches for human malignant mesothelioma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5557. doi:10.1158/1538-7445.AM2013-5557
Abstract 5566: CARP-1 functional mimetics (CFMs): a novel class of small molecule inhibitors (SMIs) of medulloblastoma cell growth.
Authors: Ashour Abdelkader E. , Jamal Shazia , Cheryan Vino , Alafeefy Ahmed M. , Levi Edi , Tarca Adi L. , Polin Lisa A. , Rishi Arun K.
Published: August 2014

Medulloblastomas (MBs) are an aggressive class of intracranial pediatric tumors. Current multimodality treatments for MBs include surgery, ionizing radiation, and chemotherapy. Toxic side effects of therapies coupled with high incidence of recurrence and the metastatic spread warrants development of more effective, less toxic therapies for this disease. CARP-1/CCAR1 is a peri-nuclear phospho-protein that is a co-activator of the cell cycle regulatory anaphase promoting complex/cyclosome (APC/C) E3 ligase. CARP-1 functional mimetics (CFMs) are a novel class of small molecule compounds that interfere with CARP-1 binding with APC/C subunit APC-2, and suppress growth of a variety of cancer cells in part by promoting apoptosis. Here we investigated MB growth inhibitory potential of the CFM-1, 4, and 5, and found that CFMs inhibit growth of MB cells. CFM suppression of MB cell growth involved elevated CARP-1 expression, activation of pro-apoptotic stress-activated protein kinase (SAPK) p38, and apoptosis. Gene-array-based analysis of the CFM-4-treated Daoy MB cells indicated down-regulation of a number of key cell growth and metastasis-promoting genes including cell motility regulating small GTP binding protein p21Rac1, and extracellular matrix metallopeptidase (MMP)-10. Moreover, CFM-4 treatment stimulated expression of a number of growth inhibitory and apoptosis-inducing molecules such as neurotropin (NTF)3, while knock-down of NTF3 interfered with MB growth inhibitory effects of CFM-4. CFMs also attenuated biological properties of the MB cells by blocking their abilities to migrate, form colonies in suspension, and invade through the matrix-coated membranes. Together our data support anti-MB properties of CFM-4, and provide a proof-of-concept basis for further development of CFMs as potential anti-cancer agents for MBs.

Citation Format: Abdelkader E. Ashour, Shazia Jamal, Vino Cheryan, Ahmed M. Alafeefy, Edi Levi, Adi L. Tarca, Lisa A. Polin, Arun K. Rishi. CARP-1 functional mimetics (CFMs): a novel class of small molecule inhibitors (SMIs) of medulloblastoma cell growth. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5566. doi:10.1158/1538-7445.AM2013-5566
Abstract 5568: Thermochemotherapy with controlled drug delivery using a novel magnetic anti-cancer drug .
Authors: Sato Itaru , Mitsudo Kenji , Umemura Masanari , Feng Xianfeng , Fukumura Hidenobu , Eguchi Haruki , Nakashima Hideyuki , Kioi Mitomu , Tohnai Iwai , Ishikawa Yoshihiro
Published: August 2014

Background:

Radical surgery for patients with oral cancer may cause dysfunction, such as dysphagia, dysarthria, or mastication disorders, leading to decreased quality of life in cancer patients. Here, we report the development of a novel magnetic anti-cancer drug, EI236, which may enable us to reduce such problems. EI236 possesses three features; anti-cancer effect alike cisplatin, controlled drug delivery using a magnet, and hyperthermic effect upon exposure to an alternating current magnetic field (ACMF). We thus examined the efficacy of EI236 in treating oral cancer in a rabbit cancer model.

Methods:

Cell proliferation was measured by MTT assays. We established the rabbit tongue cancer model using VX2 cells, which are readily transplantable in vivo. Electromagnet was used to attract EI236 to the site of tongue cancer by controlled drug delivery (CDR), and ACMF to generate heat from EI236 (HT). Rabbits were divided into 4 groups: control group, intravenous EI236 injection group (5mg/kg×7days) (i.v.), intravenous EI236 injection + electromagnet group (i.v. + CDR), intravenous EI236 injection + electromagnet + ACMF group (i.v. + CDR + HT). The size of tumors was measured daily for 7 days, followed by histopathological evaluation. Of note, EI236 was injected at the same dose in the three groups.

Results:

EI236 showed anti-cancer effects in a dose-dependent manner in VX2 cells. The IC50 value of EI236 was 7.5μM in cultured cells. The resultant tumor volume after EI236 i.v. injection treatment in rabbits was as follows; 319.3±40.0% for control, 228.5±94.3% for i.v., 91.5±27.4X% for i.v. + CDR, 24±8.2% for i.v. + CDR + HT, indicating that the i.v. + CDR + HT group showed the greatest decrease. It also showed the largest necrotic area in H-E staining analysis. The tumor cell nucleus, as determined by Ki67 staining, were mostly disappeared.

Conclusion:

Anti-cancer effect of EI236 was synergistically increased in the presence of CDR and/or HT. EI236 may serve as a novel anti-cancer therapy that enables CDR and HT at the same time.

Citation Format: Itaru Sato, Kenji Mitsudo, Masanari Umemura, Xianfeng Feng, Hidenobu Fukumura, Haruki Eguchi, Hideyuki Nakashima, Mitomu Kioi, Iwai Tohnai, Yoshihiro Ishikawa. Thermochemotherapy with controlled drug delivery using a novel magnetic anti-cancer drug . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5568. doi:10.1158/1538-7445.AM2013-5568
Abstract 5575: Strigolactones: a novel class of plant hormones inhibit cancer cell and cancer stem-like cell growth and survival.
Authors: Yarden Ronit I. , Pollock Claire B.
Published: August 2014

Strigolactones (SLs) are a novel class of plant hormones produced in roots and regulate new above ground shoot branching, by inhibiting self-renewal of undifferentiated meristem cells. Here we show that Strigolactone analogues are able to inhibit proliferation and induce apoptosis of several different types of cancer cells including breast, prostate, lung, colon and osteosarcoma cells but not ‘non-cancer’ lines. Given the therapeutic problem of cancer recurrence which is hypothesized to be due to drug resistant cancer stem cells, we also tested the ability of Strigolactone analogues to inhibit cancer stem cell growth. We show that Strigolactones are potent inhibitors of self-renewal and survival of breast cancer cell lines grown as cancer stem cell enriched mammospheres and even a short exposure leads to irreversible effects on mammosphere dissociation and cell death. Cell cycle analysis showed that all five strigolactone analogues induced G2/M arrest, coupled with increased percentages of cells in the sub-G1 fraction. AnnexinV staining confirmed that Strigolactone treatment induced apoptosis. Strigolactone treatment was hallmarked by increased expression of genes involved in stress signaling, as well as apoptosis, metabolic function and cellular adhesion. Immunoblot analysis of strigolactone treated cells also revealed increased phosphorylation of the stress activated MAPKs: p38 and JNK1/2 and decreased phospho-ERK1/2 and phospho-AKT. In summary, Strigolactones are promising candidates for anticancer therapy by their ability to induce cell cycle arrest and apoptosis in cell lines derived from a wide array of different cancers.

Citation Format: Ronit I. Yarden, Claire B. Pollock. Strigolactones: a novel class of plant hormones inhibit cancer cell and cancer stem-like cell growth and survival. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5575. doi:10.1158/1538-7445.AM2013-5575

Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.
Abstract 5584: Finding predictive markers for tumor response to classical cytotoxic drugs.
Authors: Borst Piet , Rottenberg Sven
Published: August 2014

As attempts to find predictive markers for cytotoxic drugs have been relatively unsuccessful using patient tumor samples (1), we are using a mouse model for BRCA1-deficient mammary tumors to search for such markers. Although these tumors originate in inbred mice from an inactivating deletion of the Brca1 and p53 genes, their response to doxorubicin (2), docetaxel (2), topotecan (3) and PARP inhibitors (4) varies. We have shown that in this tumor model 5 of the 22 tumors respond poorly to docetaxel, because of upregulated drug-transporting P-glycoproteins (5). These 5 were not found by standard gene expression analytical tools, such as significance analysis of microarrays (SAM), and we have shown that SAM only detects resistance markers if present in more than half the tumor samples (5). Better algorithms for the detection of resistance determinants in a subfraction of tumors are being developed by De Ronde and Wessels (5). We are still searching for the cause of the poor docetaxel response in 17 of the 22 tumors.

1. Borst,P. and Wessels,L. (2010). Do predictive signatures really predict response to cancer chemotherapy? Cell Cycle 9, 4836-4840.

2. Rottenberg,S., et al (2007). Selective induction of chemotherapy resistance of mammary tumors in a conditional mouse model for hereditary breast cancer. Proc. Natl. Acad. Sci. U. S. A. 104, 12117-12122.

3. Zander,S., et al (2010). Sensitivity and acquired resistance of BRCA1; -53-deficient mouse mammary tumors to the topoisomerase I inhibitor topotecan. Cancer Res. 70, 1700-1710.

4. Rottenberg,S., et al (2008). High sensitivity of BRCA1-deficient mammary tumors to the PARP inhibitor AZD2281 alone and in combination with platinum drugs. Proc. Natl Acad. Sci. U. S. A 105, 17079-17084.

5. Rottenberg,S., et al (2012). Impact of intertumoral heterogeneity on predicting chemotherapy response of BRCA1-deficient mammary tumors. Cancer Res 72, 2350-2361.

Citation Format: Piet Borst, Sven Rottenberg. Finding predictive markers for tumor response to classical cytotoxic drugs. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5584. doi:10.1158/1538-7445.AM2013-5584
Abstract 559: The molecular kinetics of p21 and Cdk4 dictates irreversible G0/G1 phase cell cycle arrest in CRPC cells.
Authors: Gulappa Thippeswamy , Reddy Rama S. , Suman Suman , Damodaran Chendil
Published: August 2014

Deregulation of cell cycle progression is the hallmark of cancer; to this effect, several small molecules (AG-024322, AT7519, E7070, P1446A-05 and Flavopiridol) against cell cycle kinases are being developed to regulate cell cycle machinery that resulted in inhibition of tumor growth. The present study examined the effect of 3, 9-dihydroxy-2-prenylcoumestan-a furanocoumarin (Pso) on castration resistant prostate cancer cells (CRPC) cells. Treatment of CRPC (PC-3 and C4-2B) cells with Pso significantly caused irreversible G0-G1 cell cycle arrest that resulted in inhibition of cell proliferation. Protein analysis suggested that the expression of cdk inhibitors (CDKI) p21cip1 and p27kip1 were upregulated in both CRPC cell lines by Pso treatment. Studies using real-time reverse transcription-polymerase chain reaction analysis suggest that Pso transcriptionally regulates p21cip1 and p27kip1 in CRPC cells. Our immunofluorescence analysis pointed out that both p21cip1 and p27kip1 accumulated in the nucleus upon the treatment as compared to untreated CRPC cells. In addition, the cell cycle arrest was associated with decreased levels of both cyclins and cyclin-dependent kinases. However, cdk-4 appears to be more significantly downregulated when compared with either cyclins (D1, D2, D3 and Cyclin E) or other Cdk's (cdk2/6). Also, we noted an increased hypophosphorylated level of retinoblastoma (Rb) with a decreased in Rb phosphorylation resulted in inhibition of E2F1 function. Further, transient over expression of Cdk4 overcomes the Pso-induced G0-G1 arrest in CRPC cells. Also, knockdown of p21cip1 and p27kip1 expression with small interfering RNA significantly abrogated the Pso-induced G0-G1 cell cycle arrest suggested that induction of p21cip1 and p27kip1 is required for G0-G1 cell cycle arrest by Pso. Altogether our results strongly suggest that Pso could be a potential candidate for prevention and therapy against CRPC. Our ongoing studies using xenograft models of CRPC in nude mice may reveal the in vivo efficacy of Pso.

Citation Format: Thippeswamy Gulappa, Rama S. Reddy, Suman Suman, Chendil Damodaran. The molecular kinetics of p21 and Cdk4 dictates irreversible G0/G1 phase cell cycle arrest in CRPC cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 559. doi:10.1158/1538-7445.AM2013-559
Abstract 5592: FGFR4-mediated anti-apoptotic signaling classifies subtypes of alveolar rhabdomyosarcoma cells.
Authors: Wachtel Marco , Rakic Jelena , Okoniewski Michal , Bode Peter , Schäfer Beat
Published: August 2014

Both conventional and targeted treatments of cancer are effective only in subsets of patients. A major obstacle for any treatment directed against a certain tumor type is the biological heterogeneity of tumors. Therefore, characterization of treatment-relevant tumor heterogeneity is necessary to develop more specific, tumor-tailored treatments in the future. Here, we evaluated heterogeneity among alveolar rhabdomyosarcoma (aRMS) by assessing differences in anti-apoptotic signaling mediated by FGFR4, a receptor commonly activated in this tumor type. We found that FGFR4 signaling rescues subgroups of aRMS cell lines from apoptosis induced by compounds targeting the IGF1R-PI3K-mTor pathway or by different chemotherapeutics. As a result of differences of involved apoptotic signaling mechanisms composition of the subgroups is compound-dependent. IGF1R-PI3K-mTor targeted treatment induced apoptosis via Bim/Bad in the rescue and via Bmf in the non-rescue group of cells. Gene expression analysis detected signatures specific for these two cell types also in biopsy samples. Expression levels of AP2β discriminate the two cell types and reveal that both cell types are present in different ratios in most aRMS tumors. Behaviour of Rh30 cells suggests that the two cell types reflect different activation states of PAX/FKHR, the fusion transcription factors present in most aRMS and that environmental stimuli can induce a phenotype switch. Combination of targeted or untargeted drugs with FGFR inhibitors therefore represents an opportunity to improve therapeutic efficacy against aRMS cells with active anti-apoptotic FGFR4 signaling.

Citation Format: Marco Wachtel, Jelena Rakic, Michal Okoniewski, Peter Bode, Beat Schäfer. FGFR4-mediated anti-apoptotic signaling classifies subtypes of alveolar rhabdomyosarcoma cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5592. doi:10.1158/1538-7445.AM2013-5592
Abstract 5605: Pharmacologic inhibition of EphA2 in NRAS and BRAF mutant melanomas.
Authors: Miao Benchun , Zhang Jianming , Ji Zhenyu , Njauw Ching Ni , Taylor Michael , Kumar Raj , Gray Nathanael , Tsao Hensin
Published: August 2014

The Eph receptors are the largest known family of receptor tyrosine kinases (RTKs). Research studies have shown that Eph receptors and ligands may be involved in many diseases including cancer. EphA2 is a member of the Eph family of receptor tyrosine kinases and is highly expressed in many aggressive cancer types, including melanoma. Our previous studies showed that EphA2 levels are elevated in melanoma cells and EphA2 plays critical roles in melanoma cell survival, proliferation, colony formation and migration in vitro and melanoma tumor growth in vivo. Together, these data suggest that EphA2 is a critical oncogene in melanoma and a potential pharmacologic target in the treatment of metastatic disease. Herein we present early evidence that EphA2 inhibitors (ALW-II-41-27 and HG-6-64-1) are effective in inhibiting proliferation of both NRAS and BRAF mutant melanoma cell lines in vitro through suppressing a series of EphA2 downstream signaling pathways. At the same time, EphA2 inhibitors are also effective at suppressing migration and invasion of melanoma cells with a reduction in actin cytoskeleton reorganization and lamellipodia formation. Animal studies are underway to determine the effectiveness of these agents in suppressing melanoma tumor growth in vivo. These results point to EphA2 inhibition as a promising therapeutic strategy for both NRAS and BRAF mutant melanomas either singly or in combination with BRAF or MEK inhibitors currently in trial.

Citation Format: Benchun Miao, Jianming Zhang, Zhenyu Ji, Ching Ni Njauw, Michael Taylor, Raj Kumar, Nathanael Gray, Hensin Tsao. Pharmacologic inhibition of EphA2 in NRAS and BRAF mutant melanomas. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5605. doi:10.1158/1538-7445.AM2013-5605
Abstract 5606: Gallium maltolate inhibits brain tumor volume and blood volume in xenograft model.
Authors: Pechman Kimberly R. , Lozen Andrew , Al-Gizawiy Mona , Schmainda Kathleen , Chitambar Christopher R.
Published: August 2014

Purpose: There are limited treatment options for glioblastomas (GBM). Tumor cells have a high requirement for iron; the latter is taken up by cells through transferrin receptor-mediated endocytosis of transferrin-iron. These receptors are highly expressed on GBM cells, which makes them an attractive target for transferrin receptor-directed therapies. Gallium is a group IIIa metal that can function as an iron mimetic by avidly binding to transferrin and incorporating into cells through the transferrin receptor. No studies have been performed to determine the efficacy of gallium-based therapies in brain tumors. Consequently, the goal of this study was to evaluate gallium maltolate in the treatment of a U87 xenograft brain tumor model. Methods: Athymc rats bearing U87 human grade IV astrocytoma cells were studied. Gallium maltolate (50 mg/kg/day, n=5) or saline (n=3) was given intravenously. via an alzet mini pump in the jugular vein. Magnetic resonance imaging (MRI) was performed on days 8 and 18 on a Bruker 9.4 T scanner. Enhancing tumor volumes were determined from the post-contrast T1w images, in all slices showing enhancing tumor. The spin and gradient echo relaxation rate changes were then determined giving estimates of microvascular and total blood volume. ((CBVmicro≈R2=R2MION-R*pre-MION CBVTotal≈ R2* = R2*MION-R2*pre-MION). Results: Gallium maltolate inhibited tumor growth (377132%), as measured by enhancing tumor volume, compared to saline controls (863481%). Treatment shows decrease of CBV micro and CBVTotal compared to the controls. The ratio of R2* /R2, which is a measure of mean vessel diameter, increased in saline treated controls but remained unchanged for the gallium maltolate treated rats. To our knowledge this is the first study performed that uses physiologic MRI measurements to investigate the effects of gallium maltolate on brain tumor xenografts. The differences shown are not statistically significant a result likely due to the small sample sizes, which is being remedied by ongoing additional studies. For the imaging studies included here tissue markers of proliferation (Ki67), hypoxia (HIF1) transferrin receptors, and vascular density (vWF) are being analyzed to provide additional information regarding mechanism of action. In general these results demonstrate, for the first time, that the novel gallium maltolate treatment holds promise for the treatment of malignant brain tumors.

Citation Format: Kimberly R. Pechman, Andrew Lozen, Mona Al-Gizawiy, Kathleen Schmainda, Christopher R. Chitambar. Gallium maltolate inhibits brain tumor volume and blood volume in xenograft model. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5606. doi:10.1158/1538-7445.AM2013-5606
Abstract 5608: Iron depletion by deferasirox have a synergistic effect on sorafenib in hepatocellular carcinoma.
Authors: Urano Shinichi , Ohara Toshiaki , Watanabe Shinichiro , Noma Kazuhiro , Tomono Yasuko , Tazawa Hiroshi , Kataoka Masafumi , Kazuhiro Nouso , Shirakawa Yasuhiro , Fujiwara Toshiyoshi
Published: August 2014

Purpose. Sorafenib is a multiple kinase inhibitor approved for advanced hepatocellular carcinoma(HCC). However, we couldn't get sufficient effect in clinical use compared to other cancers. Iron metabolism and relationship with cancer cells have been studied for a long time. Iron overload is known to associate with an increased risk of HCC, and the recent study suggests that iron depletion can induce anti-cancer effect against HCC. We hypothesized that iron depletion enhance the effect of sorafenib and investigated it.

Experimental Design. HepG2 (Human hepatocellular liver carcinoma cell line) was used in this study. We used sorafenib and an oral iron chilator, deferasirox (EXJADE TM). The effects of each agent and combination of both were examined by using cell viability assay. We examined anti-proliferative mechanism in vitro using Flow Cytometry and Western blot analysis.

Results. We examined the cell viability of HepG2. Each treatment by sorafenib and deferasirox suppressed the cancer cell proliferation on dose dependent manner. The IC50 values of 48hours of sorafenib was 1.45μM/L,and that of deferasirox was 1.37μM/L. We examined the possibility of combination therapy. The each cell viability of sorafenib 1μM and deferasirox 10μM was 59.4% and 28.1%, the combination one was 21.8%. The combination index was 0.616 in that status, which suggested synergistic effect. To evaluate anti-proliferation mechanism, we performed Flow Cytometry and Western blot analysis. In Flow Cytometry, S and G2/M phase was significantly decreased, which suggested to arrest cell cycle. In Western blot analysis, cyclin D1 was down-regulated.

Conclusion. Iron depletion by deferasirox have anticancer effect by alone and a synergistic effect in combination with Sorafenib. This result suggested that iron depletion therapy can be a novel combination chemotherapy for HCC.

Citation Format: Shinichi Urano, Toshiaki Ohara, Shinichiro Watanabe, Kazuhiro Noma, Yasuko Tomono, Hiroshi Tazawa, Masafumi Kataoka, Nouso Kazuhiro, Yasuhiro Shirakawa, Toshiyoshi Fujiwara. Iron depletion by deferasirox have a synergistic effect on sorafenib in hepatocellular carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5608. doi:10.1158/1538-7445.AM2013-5608
Abstract 5617: A new alphaV/beta3 integrin selective carrier for nanodrug delivery to tumors based on isoDGR-tagged albumin.
Authors: Curnis Flavio , Sacchi Angelina , Longhi Renato , Colombo Barbara , Gasparri Anna , Corti Angelo
Published: August 2014

Albumin is emerging as a versatile drug carrier in a number of applications in cancer therapy and diagnosis. Basically, albumin can be exploited to enhance the tumor uptake of peptides and low molecular-weight compounds, owing its tendency to accumulate in tumors, and for the preparation of nanoparticles that encapsulate anti-cancer drugs or diagnostic agents.

We have addressed the hypothesis that coupling albumin with a peptide containing the isoAsp-Gly-Arg (isoDGR) sequence, a tumor-vasculature targeting motif discovered by our group, might enhance its tumor-homing properties. IsoDGR is a mimetic of Arg-Gly-Asp (RGD), an integrin-recognition motif. Accordingly, isoDGR can recognize RGD-dependent integrins with different affinity and selectivity depending on isoDGR conformation and molecular scaffold. To have at hand isoDGR peptides that can be easily coupled to albumin we designed various head-to-tail-cyclized exapeptides containing free thiol groups, to enable chemical coupling to proteins, and analyzed their integrin binding properties before and after coupling to albumin. We have identified a peptide (c(CGisoDGRG)) that, after coupling to human serum albumin, has a very good selectivity for alphaV/beta3 and alphaV/beta5, two integrins overexpressed in the tumor vasculature. In vitro and in vivo studies showed that isoDGR-tagged albumin binds to endothelial cells, inhibits their adhesion properties, homes in on tumor vessels and inhibits tumor growth, with no evidence of toxicity. IsoDGR-tagged albumin was exploited as a carrier for the preparation of a new nano-gold systems capable of delivering tumor necrosis factor α (TNF), a well known vascular damaging agent, to tumor vessels. In vivo studies, performed with mice bearing WEHI-fibrosarcomas, showed that intravenous administration of gold nanoparticles loaded with isoDGR-tagged albumin and TNF (equivalent 5 pg of bioactive TNF/mouse) could induce stronger anti-tumor effects than nanoparticles loaded with albumin and TNF. These findings support the concept that isoDGR-tagged albumin is superior to albumin as a vector system for targeted delivery of nanomedicines to tumor vessels. Because of its good selectivity for tumor vessels and its inherent anticancer activity isoDGR-tagged albumin might be exploited as a novel and versatile material for the preparation of a wide range of tumor vasculature-selective drugs and nanoparticles for cancer therapy and diagnosis.

Citation Format: Flavio Curnis, Angelina Sacchi, Renato Longhi, Barbara Colombo, Anna Gasparri, Angelo Corti. A new alphaV/beta3 integrin selective carrier for nanodrug delivery to tumors based on isoDGR-tagged albumin. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5617. doi:10.1158/1538-7445.AM2013-5617
Abstract 5619: Preclinical development of anti-SLC34A2 antibody drug conjugate as a therapeutic for non-small cell lung and ovarian cancers.
Authors: Lin Kedan , Zhang Crystal , Harstad Eric , Hiraragi Hajime , Solis Willy , Tsai Siao Ping , Xu Keyang , Hristopoulos Maria , Venook Rayna , Rubinfeld Bonnee , Polakis Paul
Published: August 2014

SLC34A2, also known as type II Na/Pi co-transporters NaPi2b or NaPi3b, is a member of solute carrier protein family SLC34. SLC34A2 is highly expressed on cancers of the lung, ovary and thyroid as well as on normal lung pneumocytes, and is a promising target for antigen-directed therapy. Antibody drug conjugates (ADCs) specify the delivery of a cytotoxic drug to cells expressing an accessible antigenic target. Here we have appended monomethyl auristatin E (MMAE) to an antibody recognizing SLC34A2. Anti-SLC34A2-vc-MMAE inhibits tumor growth in multiple ovarian and non-small cell lung cancer xenograft models that express SLC34A2. Anti-SLC34A2 antibody and its conjugate cross-react with both human and monkey, and toxicity studies in monkeys are conducted to identify both target- and MMAE-related effects. Anti-SLC34A2-vc-MMAE was well tolerated in monkeys at efficacious doses and produced dose-related bone marrow suppression and increased apoptosis and mitotic figures consistent with MMAE-related pharmacology. Despite high levels of expression in normal lung of non-human primate, the cross-reactive ADC exhibited an acceptable safety profile with a dose-limiting toxicity unrelated to normal tissue expression. Overall, our preclinical results suggest that the antibody drug conjugate targeting the SLC34A2 may provide an effective new therapy for the treatment of NSCLC and ovarian cancer.

Citation Format: Kedan Lin, Crystal Zhang, Eric Harstad, Hajime Hiraragi, Willy Solis, Siao Ping Tsai, Keyang Xu, Maria Hristopoulos, Rayna Venook, Bonnee Rubinfeld, Paul Polakis. Preclinical development of anti-SLC34A2 antibody drug conjugate as a therapeutic for non-small cell lung and ovarian cancers. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5619. doi:10.1158/1538-7445.AM2013-5619
Abstract 5626: EBP50: Novel biomarker for resistance to endocrine and HER-2 targeted therapies in breast cancer. .
Authors: Gu Guowei , Corona-Rodriguez Arnoldo , Covington Kyle , Fernandez Natalie , Zhou Jianling , Cai Weiyan , Ando’ Sebastiano , Fuqua Suzanne A.W.
Published: August 2014

Backgroud: Na+/H+ Exchanger Regulatory Factor (NHERF1) also named ERM Binding Protein 50 (EBP50) functions as a molecular scaffold to coordinate ion transport and second messenger signal transduciton. Recently, a number of studies suggest a role for EBP50 expression in cancer progression.

Methods: Microarray profiling. Stable transfection. Soft agar and MTT growth assays. Immunoblot and immunoprecipitation assays. Confocal microscopy. Duolink in situ.

Results: The mean levels of EBP50 were reduced in tamoxifen (Tam)-resistant, metastatic breast tumors compared to Tam-sensitive tumors. Knockdown of EBP50 decreased Tam sensitivity in MCF-7 and ZR-75B cells. EBP50 knockdown cells showed higher levels of phosphorylated HER2 and EGFR, as well as their downstream signalling pathways. PI3K/AKT inhibitors were able to restore Tam sensitivity in knockdown cells. Similarly, knockdown EBP50 in ERα/HER2 positive BT-474 cells increased constitutive pHER2 and these cells were resistant not only to Tam, but also to Trastuzumab (Tras) treatment. An EGFR inhibitor or Lapatinib were able to restore Tras sensitivity. Overexpression of EBP50 restored Tam sensitivity in BT-474 cells. We demonstrate that EBP50 is capable of binding to HER2 and ERα using immunoprecipitation and PLA assay, suggesting that EBP50 interacts directly with both. Overexpression of EBP50 decreased pHER2 and pEGFR levels suggesting that EBP50 can downregulate its activity. EBP50 overexpression upregulated ERα transcriptional activity. ERα transcriptional activity in cells overexpressing EBP50 was costitutively higher and more sensitive to Tam. We previously published that Dicer overexpression and loss of RhoGDIα were associated with Tam resistance. Interestingly, EBP50 knockdown was associated with higher Dicer and lower RhoGDIα levels suggesting that Tam resistance is associated with inter-related mechanisms. We performed microarray analysis and identified kinase signiture in EBP50 knockdown cells. This kinase signature predicts Tam resistance. Our data suggest that EBP50 is a novel negative regulator of HER2 signaling, and its loss confers resistance to both Tam and Tras. We hypothesize that EBP50 levels might be a new predictive biomarker for targeted therapy.

Citation Format: Guowei Gu, Arnoldo Corona-Rodriguez, Kyle Covington, Natalie Fernandez, Jianling Zhou, Weiyan Cai, Sebastiano Ando’, Suzanne A.W. Fuqua. EBP50: Novel biomarker for resistance to endocrine and HER-2 targeted therapies in breast cancer. . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5626. doi:10.1158/1538-7445.AM2013-5626
Abstract 5635: Development of a high-throughput cell and fluorescent image-based ABCB1-mediated efflux assay for screening inhibitors of ABCB1.
Authors: Ansbro Megan R. , Shukla Suneet , Ambudkar Suresh V. , Yuspa Stuart H. , Li Luowei
Published: August 2014

ABCB1, also known as P-glycoprotein (P-gp) or multidrug resistance protein 1 (MDR1), is a membrane-associated multidrug transporter of the ATP-binding cassette (ABC) transporter family. It is one of the most widely studied transporters that enable cancer cells to develop drug resistance. Reliable high-throughput assays that can identify compounds that interact with ABCB1 are crucial for developing new therapeutic drugs. A high-throughput assay for measuring ABCB1-mediated calcein AM efflux was developed using the IncuCyteFLR technology. Time- and dose-dependent accumulation of fluorescent calcein in ABCB1-overexpressing KB-V1 cells was recorded using the IncuCyteFLR. Validation of the assay was performed with known ABCB1 inhibitors, XR9576, verapamil, and cyclosporin A, all of which displayed dose-dependent inhibition of ABCB1-mediated calcein AM efflux in this assay. A kinase inhibitor library and other compounds with known therapeutic targets were screened. The assay is highly reproducible and inhibitors for ABCB1-mediated efflux were identified from the kinase inhibitor library. Among compounds with known targets, BEZ235, BI 2536, IKK 16, and Ispinesib (SB-715992) inhibited calcein AM efflux in a dose-dependent manner and were also active in the flow cytometry based efflux assay. BEZ235, BI 2536, and IKK 16 also successfully competed with radiolabeled photoaffinity substrate [125I]iodoarylazidoprazosin (IAAP) for binding to ABCB1. Inhibition of ABCB1 lowered the IC50 value of BI 2536 treated ABCB1-overexpressing cancer cells. Phase and fluorescent images taken by the IncuCyteFLR provided additional opportunities for evaluating compounds that are cytotoxic or produce false positive signals. This high-throughput assay provides an efficient, reliable, and simple technique for screening libraries of natural and synthetic compounds to identify ABCB1 inhibitors. The same approach may be applied to screen inhibitors of other ABC transporters when suitable cell lines and fluorescent substrates are used.

Citation Format: Megan R. Ansbro, Suneet Shukla, Suresh V. Ambudkar, Stuart H. Yuspa, Luowei Li. Development of a high-throughput cell and fluorescent image-based ABCB1-mediated efflux assay for screening inhibitors of ABCB1. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5635. doi:10.1158/1538-7445.AM2013-5635
Abstract 5636: Different characteristics of drug resistance in AML cell lines between a dual Flt3/CDK4 kinase inhibitor AMG 925 and Flt3 inhibitors.
Authors: Li Cong , Liang Lingming , Beaupre Darrin , Newhall Katie , Li Zhihong , Wang Queenie , Xia Zhen , Liu Qiang , McGee Larry , Wickramasinghe Dineli , Dai Kang
Published: August 2014

Objectives: Flt3 inhibitors have shown clinical responses in Flt3 mutant acute myeloid leukemia (AML) but resistance develops rapidly. In order to improve the durability of clinical response of AMLFlt3 MUT, a small molecule inhibitor of Flt3 and CDK4/6 kinases, AMG 925, was developed. The primary purpose of this study is to compare the ability of AML cell lines to become resistant to AMG 925 and to other Flt3 inhibitors, and to elucidate the underlying molecular mechanisms.

Methods: Drug resistant MOLM13 and Mv4-11 cell clones were isolated by prolonged exposure to increasing concentrations of AMG 925 and other Flt3 inhibitors. Cell proliferation was determined by CellTiter Glo. Protein expression levels were assessed by Western Blotting, IP Western Blotting and MSD assays. Flt3 mRNA levels were measured by RT-PCR.

Results and Conclusions: Both MOLM13 and Mv4-11 cells developed resistance to all the inhibitors tested within 3-4 months. In contrast to AML cells resistant to other Flt3 inhibitors (IC50 increased by about 1000 fold), cells resistant to AMG 925 were only at much lower drug concentrations (IC50 increased by 3-5 fold). Mutations in the Flt3 kinase domains were found in cells resistant to the other Flt3 inhibitors but not in those resistant to AMG 925. P-Flt3 and P-STAT5 in AMG 925 resistant cells were less inhibited than in the sensitive parental cells, apparently as a result of an increased total Flt3 (2-3 fold) in the resistant cells. These results are consistent with the hypothesis that it is more challenging for AML cells to develop drug resistance against combined inhibition of Flt3 and CDK4/6 (AMG 925) than against inhibition of Flt3 alone.

Citation Format: Cong Li, Lingming Liang, Darrin Beaupre, Katie Newhall, Zhihong Li, Queenie Wang, Zhen Xia, Qiang Liu, Larry McGee, Dineli Wickramasinghe, Kang Dai. Different characteristics of drug resistance in AML cell lines between a dual Flt3/CDK4 kinase inhibitor AMG 925 and Flt3 inhibitors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5636. doi:10.1158/1538-7445.AM2013-5636
Abstract 565: An investigation into the potential therapeutic benefit of targeting Skp2 in neuroblastoma.
Authors: Evans Laura , Willmore Elaine , Tweddle Deborah A. , Newell David R.
Published: August 2014

Background: S-phase kinase-associated protein 2 (Skp2) is a component of an E3 ubiquitin ligase complex which targets several key regulators of the G1/S transition of the cell cycle. Skp2 is overexpressed in many cancers and has been implicated in tumourigenesis due to its ability to degrade the cyclin-dependent kinase inhibitors p27Kip1 and p21Cip1, promote S phase entry and induce growth. We identified Skp2 as a possible MYCN target gene in neuroblastoma (Bell et al, Cell Cycle, 2007), and other groups have reported an increase in Skp2 transcript levels in aggressive MYCN- amplified neuroblastoma (Westermann et al, Clinical Cancer Res 2007). As MYCN amplification is a well-established poor prognostic marker we hypothesise that targeting Skp2 may be a potential therapeutic approach for neuroblastoma, especially the MYCN-amplified subtype.

Methods: The relationship between MYCN and Skp2 was investigated using the SHEP Tet21N-regulatable MYCN expression system and Skp2 siRNA. The effects of Skp2 knockdown on downstream proteins (p21, p27), cell cycle arrest and cell apoptosis were analysed using western blotting, flow cytometry, and the caspase-3/7 glow assay, respectively.

Results: A decrease in Skp2 and subsequent increase in p27 and p21 levels was seen in SHEP Tet21N cells when MYCN expression was suppressed. A G1 arrest was also induced by MYCN removal, an effect mirrored after Skp2 knockdown in Tet21N MYCN+ cells. Skp2 knockdown increased both p27 and p21 levels in non-MYCN amplified SHSY5Y cells and MYCN amplified IMR-32 cells. Both cell lines had ∼20% reduction (p<0.01) in growth after 72 hours knockdown compared to the scrambled control. However, only SHSY5Y cells showed a G1 arrest (p<0.05) and increase in caspase activity (p<0.05).

Conclusions: These data further establish the relationship between MYCN and Skp2. The effect of Skp2 knockdown on growth arrest and apoptosis suggest it would be a valid therapeutic target in neuroblastoma.

Citation Format: Laura Evans, Elaine Willmore, Deborah A. Tweddle, David R. Newell. An investigation into the potential therapeutic benefit of targeting Skp2 in neuroblastoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 565. doi:10.1158/1538-7445.AM2013-565
Abstract 5650: Determinants of acquired resistance to PI3K/mTOR inhibition in cells refractory to EGFR inhibition.
Authors: Koh King Xin , Bhattacharya Bhaskar , Loh Joanne , Ng Hong Kiat , Soo Ross , Iacopetta Barry , Soong Richie
Published: August 2014

Acquired resistance to EGFR inhibitors can be mediated through PI3K/mTOR pathway activation. This has prompted the consideration of PI3K/mTOR inhibitors for treatment of EGFR inhibitor-refractory non-small cell lung cancer (NSCLC). This study aimed to generate and elucidate mechanisms of acquired resistance to BEZ235, a PI3K/mTOR inhibitor, in H1975 NSCLC cells containing the EGFR T790M resistance mutant. IC50 values of compounds were determined at 72 hours using the MTS assay. Acquired resistant clones of H1975 were generated by continual exposure of H1975 cells to parental IC50 concentrations of BEZ235, followed by monoclonal selection. Protein levels, cell invasion/migration, and cell cycle analysis were evaluated using standard techniques. Apoptosis was measured using Roche Cell Death kit. Two resistant clones were generated with stably higher IC50 values (Clone 5 2.29uM, Clone 6 1.94uM) to parental H1975 cells (0.32uM) after 6 months. The clones were resistant to other PI3K/mTOR inhibitors but not other cytotoxic compounds or targeted agents such as EGFR/MEK inhibitors. Following BEZ235 treatment, acquired resistant clones underwent less cell cycle G1 arrest and displayed greater invasion and migration compared to parental cells. No significant differences were seen in basal levels of pRTKs, pAKT, pmTOR, pS6 and p4EBP1, and apoptosis. In summary, EGFR inhibitor-refractory cells with acquired resistance to PI3K/mTOR inhibition have been generated and characterized with phenotypes suggestive of a class-mediated mechanism of acquired resistance. Possible mediators of acquired resistance have emerged following RNA-sequencing and reverse phase protein array analyses and are currently being validated.

Citation Format: King Xin Koh, Bhaskar Bhattacharya, Joanne Loh, Hong Kiat Ng, Ross Soo, Barry Iacopetta, Richie Soong. Determinants of acquired resistance to PI3K/mTOR inhibition in cells refractory to EGFR inhibition. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5650. doi:10.1158/1538-7445.AM2013-5650