bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1095: A combination of suberoylanilide hydroxamic acid and quinacrine is an effective therapeutic approach in preclinical settings of upper gastrointestinal cancers
Authors: Zhu Shoumin , El-Rifai Wael
Published: July 2017

Background: Quinacrine (QC), an antimalarial drug, has been shown to possess anticancer effects. Suberoylanilide hydroxamic acid (SAHA) inhibits class I and class II HDACs and is approved for cancer therapy. Developing novel approaches to overcome cancer drug resistance could significantly enhance current therapeutic approaches and improve patient care.

Methods: ATP-GLO, clonogenic survival, Annexin-V apoptosis assay, comet assay and DNA double-strand breaks (DSB) kits were used. The mRNA and protein levels were evaluated by quantitative real-time PCR and Western blot analyses.

Results: A combination of QC/SAHA significantly increased cell death in all cancer cell lines and had no effect on immortalized non-cancer cell lines (HFE145, NIH-3T3 and EPC2) (P<0.01). Clonogenic survival assay indicated that QC/SAHA co-treatment led to significantly lower number of cancer cell colonies, as compared to single agents and controls (P<0.01). Of note, the QC/SAHA combination led to an increase in the the sub-G0 population in AGS (9-fold), MKN-28 (14-fold), FLO1 (5.6-fold), and SNU1 (4-fold) cells (P<0.01). These results were confirmed using the Annexin V apoptosis induced significantly higher levels of apoptosis (10 - 20 fold) as compared to single agent and control (P<0.01). Treatment with QC/SAHA combination induced high levels of DSB (>20 fold, P<0.01). Comet assay data showed increased DNA damage compared with vehicle-treated cells (8-fold, P<0.01). Western blot analysis demonstrated a notable increase in activation of PARP, caspases 3, 9 and γ-H2AX following QC/SAHA co-treatment in all cancer cell lines. Interestingly, the combination of QC/SAHA substantially decreased the protein levels of both wtP53 and mutP53 in these cells. Tumor xenograft data confirmed that a combination of QC/SAHA is more effective than a single agent in abrogating tumor growth (P<0.05).

Conclusion: Our novel findings show that QC and SAHA have a synergistic effect on cancer cell death. The results provide compelling evidence that increased DNA damage mediates the cytotoxic effect of combined QC/SAHA. Such effect is likely related to mutP53 and wtP53 protein degradation induced by QC/SAHA combination. Our findings provide a rationale for a clinical evaluation of combined QC/SAHA therapy in gastro-esophageal cancers. Ongoing studies are currently being undertaken to understand mechanisms that regulate the degradation of wtp53 and mutp53 proteins.

Citation Format: Shoumin Zhu, Wael El-Rifai. A combination of suberoylanilide hydroxamic acid and quinacrine is an effective therapeutic approach in preclinical settings of upper gastrointestinal cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1095. doi:10.1158/1538-7445.AM2017-1095
Abstract 1098: Delta-tocotrienol chemosensitizes human pancreatic tumor metastasis to gemcitabine targeting cancer stem cells
Authors: Husain Kazim , Sebti Said M. , Malafa Mokenge P.
Published: July 2017

Background: Pancreatic cancer, a lethal malignancy is the fourth leading cause of cancer-related deaths in the United States. The standard chemotherapy with gemcitabine is ineffective in patients with metastatic tumors. Pancreatic cancer stem cells (CSCs) have been implicated in the development of pancreatic cancer metastasis, resistance to chemotherapy and its recurrence following surgical extirpation. We have shown that natural vitamin E δ-tocotrienol is the most bioactive tocotrienols against pancreatic cancer in vitro as well as in vivo models. The purpose of this study was to evaluate the chemosensitization of pancreatic tumor metastasis by δ-tocotrienol to gemcitabine in vitro as well as in vivo.

Methods: In vitro human metastatic pancreatic cancer cells L3.6pl and pancreatic cancer stem cells (PCSC) were treated with gemcitabine (5 μM) and δ-tocotrienol (50 μM) alone and in combination. Treated cells used for epithelial to mesenchymal transition (EMT), migration/invasion, microsphere/spheroid, and signaling markers assays. PCSC expressing luciferase was orthotopically implanted into pancreas of Athymic nude mice (n = 20) and after one week they were randomized into four groups: 1) vehicle control (ethanol extracted olive oil), 2) gemcitabine (100 mg/kg, IP, twice a week), 3) δ-tocotrienol (200 mg/kg, orally twice a day) and 4) gemcitabine + δ-tocotrienol. The treatment was continued for 4 weeks. The tumor volume, tumor weight, metastasis were recorded.

Results: Gemcitabine slightly inhibited the growth, migration/invasion of L3.6pl and PCSC in vitro and PCSC tumor growth (tumor volume and weight) in vivo. δ-tocotrienol significantly inhibited the growth, microsphere/spheroid, migration/invasion, EMT(E-cadherin to vimentin), angiogenesis (VEGF), PCSC transcription factors (Nanog, Oct4, and Sox2), tumor growth and liver/lung metastasis compared to control. The combination of both drugs synergistically inhibited the cancer and stem cell growth, EMT, migration/invasion, microsphere/spheroid, metastasis, angiogenesis, and PCSC transcription factors in vitro as well as in vivo.

Conclusion: Vitamin E δ-tocotrienol chemosensitizes human pancreatic tumor metastasis to gemcitabine through inhibition of EMT, migration, invasion, angiogenesis, cancer stem cell self-renewal, tumor growth and metastasis.

Citation Format: Kazim Husain, Said M. Sebti, Mokenge P. Malafa. Delta-tocotrienol chemosensitizes human pancreatic tumor metastasis to gemcitabine targeting cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1098. doi:10.1158/1538-7445.AM2017-1098
Abstract 1100: Synergistic interaction between gemcitabine and PD-0325901 in C-33A cervical carcinoma cell line
Authors: Irigoyen Macarena , Castillo Gonzalo
Published: July 2017

Cervical cancer affects over half a million women worldwide, and is one of the most common causes of death in women. Treatment of cervical cancers consists of surgery, radiation, chemotherapy, or combination of therapies. However, about half of patients with advance cancer will show recurrent tumors. Signaling cascades are often dysregulated in human cancer cells making them attractive targets for combination drug therapies. PD-0325901, an inhibitor of the mitogen-activated protein kinase, is a promising target for metastatic cancer. Another drug used to treat cervical carcinoma is gemcitabine, a nucleoside analog inhibitor of the ribonucleotide reductase and DNA damage inducible protein 45a (Gadd45a). This drug is generally used in combination with other drugs, after reoccurrence of the disease state. We decided to evaluate the efficacy of gemcitabine in combination with PD-0325901 in C-33A, a metastatic cervical cancer-derived cell line. We evaluated the potency of gemcitabine and PD-0325901 alone and in combination. Cell viability after incubation with the drugs was determined at 72 hours and at 7 days by measuring ATP content. Synergy was determined assessed utilizing BIOENSIS’s suite of drug combination analysis tools including: isobologram, combination index (CI) and Bliss analysis. Isobologram analysis at 72 hours of incubation revealed that the mean values of the observed data were significantly smaller than those of the predicted maximum additive values, indicating synergy. Bliss and combination index analysis confirmed the observation, showing a synergistic effect at concentrations between 2 - 200 nM PD-0325901 and 0.3 - 3 nM gemcitabine. Similar patterns of synergy were observed with 7 day incubations of C-33A with gemcitabine and PD-0325901. These results indicate that gemcitabine and PD-0325901 showed significantly more growth inhibition than either drug alone in the C-33A tumor cell line, suggesting that the combination of gemcitabine - PD-0325901 could be used in cervical cancer therapy.

Citation Format: Macarena Irigoyen, Gonzalo Castillo. Synergistic interaction between gemcitabine and PD-0325901 in C-33A cervical carcinoma cell line [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1100. doi:10.1158/1538-7445.AM2017-1100
Abstract 1122: ATR inhibitors synergize with PARP inhibitors in killing glioblastoma stem cells and treating glioblastoma
Authors: Ning Jianfang , Wakimoto Hiroaki , Martuza Robert L. , Rabkin Samuel D.
Published: July 2017

PARP inhibitors (PARPi) have been used alone or in combination with other agents for the treatment of tumors with homologous repair (HR) deficiencies. However, challenges remain for the treatment of tumors that are PARPi-resistant or HR-proficient. Glioblastoma (GBM) is an invariably lethal tumor that is not associated with HR deficiencies. GBM stem cells (GSCs), thought to be critical for tumor growth and resistance to therapy, can be isolated from GBM specimens and are representative of the patient's tumors. GSCs exhibit variable PARPi sensitivity, with at least half being resistant. In order to enhance the antitumor efficacy of PARPi for GBM, we examined the combination of PARPi with inhibitors of oncogenic or DNA damage pathways, including inhibitors of PTEN, PI3K, ATM, ATR, and temozolomide, some of which have been reported to sensitize cancer cells to PARPi. Only inhibitors of ATR (VE821, VE822, AZ20) synergized with PARPi in killing GSCs in vitro. VE822 inhibited ATR activity both in vitro and in vivo, and modestly, but significantly, extended survival in mice bearing GSC-derived tumors. However, ATR inhibitor (ATRi) in combination with PARPi further prolonged survival, compared to each drug alone, even in mice bearing PARPi-resistant GSC-derived tumors. This is the first report that ATRi alone or in combination with PARPi is effective in treating GBM and provides a rationale for clinical trials for GBM.

Citation Format: Jianfang Ning, Hiroaki Wakimoto, Robert L. Martuza, Samuel D. Rabkin. ATR inhibitors synergize with PARP inhibitors in killing glioblastoma stem cells and treating glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1122. doi:10.1158/1538-7445.AM2017-1122
Abstract 1132: Lactate dehydrogenase expression in African American women with triple-negative breast cancer
Authors: Torres-Luquis Odalys J. , Mohammed Sulma
Published: July 2017

The incidence of breast cancer in African American women (AAW) is much lower than those of their Caucasian counterparts. However, the age adjusted mortality rates are much greater for AAW compared to Caucasian American women (CAW). These differences in survival between AAW and CAW were attributed to socioeconomic factors and access to health care. Yet, after adjusting these differences, AAW still had lower survival rates than CAW. Genetic and immunohistochemical studies have revealed that biological variations may account for this disparity. These studies have suggested as a causative: a higher prevalence of basal-like tumors in premenopausal AAW and low prevalence of luminal tumor. These are characterized by being high-grade aggressive tumors that are estrogen receptor negative (ER-), progesterone receptor negative (PR-), human epidermal growth factor receptor-2 (HER-2) +/-; with high rate of lymph node involvement. Despite this understanding, there is little evidence to indicate which genetic or non-genetic factors contribute to causing aggressive breast cancer thereby limiting the development of prevention and treatment option. We proposed that the phenotypic diversity of breast cancer might be accompanied by a corresponding diversity in protein expression patterns that can be reveal using proteomic technologies. We hypothesized that in addition to ER- and PR-, and the absence in expression of HER-2, the protein composition of triple-negative tumors varies among African-American and Caucasian. Two-dimensional gel electrophoresis, mass spectrophotometry and data analysis of protein from breast cancer tissues were used to identify differentially expressed proteins from African American and Caucasian women. Western blot of luminal and TNBC cell lines were used to confirm the expression of identified proteins. We have found that many proteins were differentially expressed in AAW breast cancer tissues compared to CAW. One of these is lactate dehydrogenase which was found to be overexpressed in tissues from AAW. Western blot analysis confirmed expression.

Citation Format: Odalys J. Torres-Luquis, Sulma Mohammed. Lactate dehydrogenase expression in African American women with triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1132. doi:10.1158/1538-7445.AM2017-1132
Abstract 1134: Tissue transglutaminase is a new therapeutic target to overcome steroid resistance in T cell acute lymphoblastic leukemia
Authors: Jung Hyun Joo
Published: July 2017

Background: The treatment response to steroid is the most important predictive factor for treatment outcome of T-cell acute lymphoblastic leukemia (T-ALL). To improve survival for steroid-resistant T-ALL patients, it is necessary to develop innovative therapeutic strategies to overcome steroid resistance. This study attempts to determine new therapeutic strategies to overcome steroid resistance for patients with T-ALL. Tissue transglutaminase (TG2) is a intracellular calcium-dependent protein cross-linking enzyme reported to be highly expressed in various metastatic or drug-resistant cancer cells, and chronic expression of TG2 constitutively activates nuclear factor kappa B (NF-kappaB).

Methods: We used biochemical and molecular methodologies to demonstrate that TG2 modulation leaded to overcome the steroid resistance in T-ALL.

Results: We generated the steroid-adapted subclones of T-ALL cell lines that were extremely less sensitive to steroid than their parent T-ALL cells. We found that steroid-resistant subclones of T-ALL cells expressed much higher levels of TG2 than their parent cells and the modulation of TG2 activities altered NF-kappaB expression in this steroid-resistant cells. Inhibition of TG2 suppressed steroid resistance and improved the cytotoxicity of leukemia cells in steroid-adapted subclones of T-ALL.

Conclusion: This study shows that TG2 expression is elevated with steroid resistance in T-ALL and the modulation of TG2 induces the cytotoxicity of steroid-adapted T-ALL. TG2 could be a new therapeutic target to overcome steroid resistance in T-ALL. Furthermore, change of TG2 expression could serve as markers of induced steroid resistance in T-ALL.

Citation Format: Hyun Joo Jung. Tissue transglutaminase is a new therapeutic target to overcome steroid resistance in T cell acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1134. doi:10.1158/1538-7445.AM2017-1134
Abstract 114: TG02 induces cell cycle arrest in glioblastoma
Authors: Su Yu-Ting , Chen Robert , Lappin Hallie , Wang Herui , Maric Dragan , Celiku Orieta , Li Aiguo , Gilbert Mark R. , Wu Jing
Published: July 2017

Dysregulated cell cycle contributes to the limitless replicative potential of cancer cells. The cyclin-dependent kinases (CDKs) and cyclins, the CDK-regulatory proteins are the key cell cycle machinery and can be targets for cancer therapy. TG02, a pyrimidine-based multi-kinase inhibitor has an anti-glioma effect which was demonstrated by our previous studies. An in vitro kinase spectrum assay of TG02 demonstrated inhibitory effects in several CDKs at the nanomolar level. To further investigate the molecular mechanisms of TG02-induced cell cycle regulation in glioma, a cell cycle analysis was performed by flow cytometry using the Click-It Edu Flow Cytometric Assay Kit in GSC923 and U251 cell lines, a human stem-like cell and patient derived cell line, respectively. Protein expression of CDKs and cyclins was tested by Western blotting. RNAseq analysis using Next Generation Sequencing was performed (only GSC923) and followed by a supervised hierarchical clustering analysis of cell cycle pathways that were derived from Qiangen’s Ingenuity Pathway Analysis (IPA). Our results showed that TG02 treatment results in G2/M-phase arrest in glioma cell lines. The protein expression of CDK1, CDK2, cyclin A2 and cyclinB1 are downregulated in both TG02 treated cell lines. Additionally, RNAseq analysis revealed downregulation of cyclins A2, B1 and B2 and significant irregulation in mRNA expression of G2/M checkpoint and spindle formation proteins, indicating G2 checkpoint and mitosis progression are also affected by TG02. Taken together, we demonstrated that TG02 induced cell cycle G2/M arrest through downregulating CDK and cyclin expression signaling in the preclinical models of glioblastoma. These findings strongly support the further investigation of TG02 as a potential therapy for malignant gliomas.

Citation Format: Yu-Ting Su, Robert Chen, Hallie Lappin, Herui Wang, Dragan Maric, Orieta Celiku, Aiguo Li, Mark R. Gilbert, Jing Wu. TG02 induces cell cycle arrest in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 114. doi:10.1158/1538-7445.AM2017-114
Abstract 1144: Dual inhibition of MEK1/2 and PLK1 specifically targets aggressive breast cancer cell population with CEP55 elevated expression
Authors: Sinha Debottam , Kalimutho Murugan , Lopez J. Alejandro , Khanna Kum Kum
Published: July 2017

Triple negative breast cancers (TNBCs), lacking the expression of ER, PR and HER2 amplification, are the most aggressive form of breast cancer (BC). Due to their heterogeneity influenced by high level of genomic instability and aneuploidy, treatment of TNBC patients is one of the biggest challenges faced in the clinics. CEP55, discovered first by our laboratory, is a key regulator of cytokinesis malfunction of which has been shown to cause multinucleation. Furthermore, ERK2/PLK1 critically regulates the functional role of CEP55 via phosphorylation of CEP55 at particular stages of mitosis, allowing it to localize to the midbody for accurate cytokinesis. Research has demonstrated association of CEP55 with various cancers especially BC as over-expression of CEP55 mRNA is associated with worse BC prognosis and poor survival. We hypothesized that, CEP55 regulates the fate of aneuploid cell population, which are highly dependent on mitotic genes for tumor progression among aggressive BC, thus can be targeted for therapy development. We have performed a series of in vitro studies demonstrating that depletion of CEP55 sensitizes cells to anti-mitotic drugs like PLK1 inhibitor (BI2536) and leads to unscheduled CDK1/Cyclin B activation and favor CDK1-Caspase 3-dependent mitotic catastrophe. We also demonstrate that ERK1/2 transcriptionally controls CEP55 mRNA and due to lack of a specific small molecule inhibitor against CEP55, inhibition of MEK1/2 using the small molecule inhibitor Selumetinib, can mimic depletion of CEP55 in vivo. Thus, we rationalized the usage of a MEK1/2 inhibitor in combination with a PLK1 inhibitor across a series of BC cell lines. We observed synthetic lethality among the aggressive hormone receptor negative cell lines, which expressed higher expression of CEP55 compared to normal like and hormone receptor positive BC cell lines with lower CEP55 level. The combination synergistically increased apoptosis of aneuploid population via premature entry of these cells into mitosis in the presence of antimitotic drugs due to exhaustion of CEP55. We have also validated this synergistic effect of MEK1/2 and PLK1 inhibition using xenograft models, results of which imitated the in vitro findings. Therefore, we propose a novel treatment strategy of MEK1/2-PLK1 dual combination for selectively targeting CEP55 over-expressing BC in the clinics.

Citation Format: Debottam Sinha, Murugan Kalimutho, J. Alejandro Lopez, Kum Kum Khanna. Dual inhibition of MEK1/2 and PLK1 specifically targets aggressive breast cancer cell population with CEP55 elevated expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1144. doi:10.1158/1538-7445.AM2017-1144
Abstract 1146: Biomarker-driven targeted oral treatment strategy for bladder cancer
Authors: Morera Daley S. , Jordan Andre , Lokeshwar Vinata B.
Published: July 2017

INTRODUCTION AND OBJECTIVE: Hyaluronic acid (HA) family of molecules, HA-synthases (HAS-1,2,3), HA-receptors (CD44, RHAMM) and hyaluronidase (HYAL-1) are markers for bladder cancer (BCa) diagnosis and predicting prognosis. HA-family promotes tumor growth and metastasis by inducing epithelial mesenchymal transition (EMT). 4-Methylumbelliferone (4-MU) is an orally bioavailable dietary supplement that inhibits HA synthesis. We evaluated the expression of HA family and EMT markers in bladder tissues as well as the antitumor effects of 4-MU as a potential targeted therapeutic agent in preclinical models of BCa.

METHODS: Quantitative PCR was used to measure mRNA expression of HA-family and EMT genes (β-catenin, Twist, and Snail) in 72 bladder tissue specimens (28 normal; 44 tumor); follow-up: 20.3±2.5 months; median 17 months. The effect of 4-MU (0-0.6 mM) on cell proliferation, apoptosis, intracellular signaling, and the expression of HA receptors, and EMT genes were examined in BCa cell lines by Q-PCR, immunoblotting, proximal ligation and PI-3K activity assays. Mechanism of action was analyzed by HA addition and mAkt overexpression. Effect of oral administration of 4-MU (100, 200-mg/kg) on tumor growth was analyzed in subcutaneous xenografts.

RESULTS: HAS-1, -2 -3, HYAL-1 and Snail levels were 10-20-fold elevated in BCa tissues as compared to normal bladder (P<0.001). In univariate analysis, HAS-1, -2, HYAL-1 and Twist levels correlated with metastasis (P<0.001); HYAL-1 was an independent predictor of metastasis. 4-MU inhibited cell proliferation, chemotactic motility and invasion in a dose-dependent manner; 50-70% inhibition at IC50 (0.4 mM) for HA-synthesis inhibition. 4-MU induced apoptosis (>3-fold) via the death receptor pathway. 4-MU downregulated HA-signaling, specifically transcript and/or protein levels of CD44, RHAMM, p-Akt, β-catenin, pβ-catenin(S552). Snail and twist were downregulated by 2-5-fold, but pβcatenin((T41/S45), pGSK-3α/β and E-cadherin levels were increased. 4-MU also inhibited CD44/PI-3K complex formation and PI-3K activity. HA addition or myristoylated Akt expression attenuated 4-MU effects. In xenograft studies, 4-MU oral treatment abrogated tumor growth of established tumors (vehicle, day 50: 766±221 mm3; 4-MU: 128±61, day 50) by abrogating HA-synthesis. No weight loss or serum or organ toxicity was observed in treated mice.

CONCULUSION: This study demonstrates that HA-family signaling is upregulated in BCa and can be specifically targeted for treatment by a non-toxic dietary supplement. Support: 7R01 CA072821-16; 7R01CA176691-03

Citation Format: Daley S. Morera, Andre Jordan, Vinata B. Lokeshwar. Biomarker-driven targeted oral treatment strategy for bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1146. doi:10.1158/1538-7445.AM2017-1146
Abstract 1152: Lipid elongation: an unexplored therapeutic target in prostate cancer
Authors: Nassar Zeyad D. , Centenera Margaret M. , Machiels Jelle , Polacek Samuel J. , Bloch Katarzyna , Tilley Wayne D. , Selth Luke A. , Swinnen Johannes V. , Butler Lisa
Published: July 2017

Dysregulated lipid metabolism is one of the hallmarks of cancer, particularly for prostate cancer (PCa). PCa cells exhibit distinctive metabolic features such as upregulation of enzymes involved in de novo synthesis, uptake and beta-oxidation of lipids, which promote prostate cancer growth, metastasis, and drug resistance. Androgen signalling is a major driver of both PCa growth and lipid metabolism in PCa cells, however the precise effects of androgens on cellular lipid composition and the molecular pathways by which androgens regulate lipid metabolism in PCa cells are yet to be elucidated. In this study we investigated the effect of androgens on the lipid composition of PCa cell membranes and the enzymes involved in lipid metabolism, and explored the influence of these enzymes on tumour cell behaviour such as cell migration, proliferation and attachment. PCa cell lines (AR positive and negative) were cultured in the absence or presence of androgens or the anti-androgen enzalutamide, and changes in intact phospholipid species were assessed by ESI-MS/MS-based lipidomics. This analysis revealed a complexity of changes in phospholipid profiles in response to androgen treatment. Strikingly, elongation of the fatty acyl chains was consistently observed for multiple phospholipid classes in response to the androgens mibolerone or 5α-dihydotestosterone, whereas inhibition of elongation was observed in the presence of enzalutamide. Transcriptional analysis of critical lipid metabolism pathways revealed that the enzymes that catalyse lipid elongation (ELOVLs) were markedly induced by androgens in multiple PCa cell lines, and siRNA depletion of these enzymes, either alone or in combination, reversed the androgen-induced fatty acyl elongation phenotype. The androgenic regulation of ELOVL enzymes was confirmed in clinical PCa cohorts and in primary tumours cultured as explants. Targeting ELOVL gene expression also significantly attenuated the tumorigenic properties of PCa cells. ELOVL downregulation decreased LNCaP cell migration, and adhesion to fibronectin. Furthermore, ELOVL knock down significantly decreased three-dimensional spheroid growth of LNCaP cells using a hang drop assay. The impact of these enzymes on the lipid profile of PCa cell membrane and cell viability, adhesion and migration suggests that they may represent promising and previously unexplored therapeutic targets.

Citation Format: Zeyad D. Nassar, Margaret M. Centenera, Jelle Machiels, Samuel J. Polacek, Katarzyna Bloch, Wayne D. Tilley, Luke A. Selth, Johannes V. Swinnen, Lisa Butler. Lipid elongation: an unexplored therapeutic target in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1152. doi:10.1158/1538-7445.AM2017-1152
Abstract 1153: Heparan sulfate proteoglycans as novel target in cancer precise therapy
Authors: Falciani Chiara , Brunetti Jlenia , Depau Lorenzo , Pini Alessandro , Riolo Giulia , Mandarini Elisabetta , Bracci Luisa
Published: July 2017

Heparan sulfate proteoglycans (HSPGs) have crucial regulatory roles in tumor onset and progression. HSPGs

are composed of a core protein and glycan chains characterized by repeated disaccharide units which can

be sulfated at different amount and position. HSPG have enormous structural diversity due to the different

possible modifications of the single saccharide units within the polysaccharide, such as position, sulphation

and acetylation. As a result HSPG can bind and modulate their binding to signaling molecules such as

growth factors, morphogens and chemokines1 .

HSPG proved to be important in mediating cancer development and progression by enhancing the binding

of growth factors, morphogens and cytokines to their cognate receptors, thus activating signaling pathways

that give rise to angiogensis, cell growth and proliferation, together with invasion and metastasis 2-3.

NT4 is a branched peptides that targets HSPGs. NT4 specifically binds to sulfated glycosaminoglycans on

cancer cells and tissues. NT4 can be conjugated to many different cytotoxic units and tracers. NT4

conjugated to paclitaxel produced tumor regression in a breast cancer orthotopic mouse model 4. NT4

conjugated to tracers can discriminate between tumor and healthy tissue in different human cancer

specimen5.

We will show the ability of NT4 to drive tracers onto tumor lesions by means of Qdots and in vivo imaging,

proving their promising features as theranostics. We will also show NT4 ability to interfere with HSPG-

modulated activities such as: tumor cell proliferation, migration and invasion of matrix; as well as

endothelial cells proliferation, migration and tube formation. NT4-HSPG interactions and consequent

modulation of signaling pathways will prove the importance of this versatile tool, NT4, in addressing tumor

cells and interfering in their cell-cell and cell-matrix communications.

Bibliography

1. Gharbaran R. et al. Tumour Biol. 2016; 37:11573-11588.

2. Purushothaman A et al. Blood. 2010; 115:2449-57.

3. Lee JH et al. J Biol Chem. 2009; 284:27167-75.

4. Brunetti, J. et al. Scientific Reports. DOI:10.1038/srep17736

5. Falciani C. et al. J Med Chem. 2013; 56:5009-18.

Citation Format: Chiara Falciani, Jlenia Brunetti, Lorenzo Depau, Alessandro Pini, Giulia Riolo, Elisabetta Mandarini, Luisa Bracci. Heparan sulfate proteoglycans as novel target in cancer precise therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1153. doi:10.1158/1538-7445.AM2017-1153
Abstract 1166: Identification of a novel quinoxaline-isoselenourea targeting STAT3 pathway as a potential melanoma therapeutic
Authors: Alcolea Verónica , Karelia Deepkamal , Pandey Manoj K. , Plano Daniel , Singh Parvesh , Irby Rosalyn B. , Palop Juan , Amin Shantu , Sanmartín Carmen , Sharma Arun K.
Published: July 2017

The prognosis for patients with metastatic melanoma remains very poor. Constitutive STAT3 activation has been correlated to larger tumor size, metastasis, acquired resistance against vemurafenib (PLX-4032), and poor patient survival suggesting its potential as a molecular target. We recently designed a series of isoseleno- and isothio-urea derivatives of several biologically active heterocyclic scaffolds. The cytotoxic effects of lead isoseleno-/isothio-urea derivatives (compounds 1/3) were studied in a panel of five melanoma cell lines, including B-RAFV600E mutant and wild type (WT) cells. Compound 1 (IC50 range 0.8-3.8 µM) showed lower IC50 values than 3 (IC50 range 8.1-38.7 µM) and the mutant B-RAF specific inhibitor PLX-4032 (IC50 range 0.4->50 µM), especially at shorter treatment time (24 h). These effects are long-lasting since melanoma cells did not recover their proliferative potential after 14 days of the treatment. In addition, we confirmed that compound 1 induces cell death by apoptosis using Live and Dead, Annexin V and Caspase3/7 apoptosis assays. Furthermore, compound 1 reduces protein levels of STAT3 and its phosphorylation, as well as decreases the expression of STAT3 regulated genes involved in survival and metastasis such as survivin and c-myc. Compound 1 also upregulates the cell cycle inhibitor p21. Docking studies further revealed the favorable binding of 1 with SH2 domain of STAT3 suggesting its activity through STAT3 inhibition. Taken together, our results suggest that compound 1 induces apoptosis by means of the inhibition of STAT3 pathway to non-specifically target both B-RAF mutant and WT melanoma cells with much better cytotoxicity than the current therapy PLX-4032.

Citation Format: Verónica Alcolea, Deepkamal Karelia, Manoj K. Pandey, Daniel Plano, Parvesh Singh, Rosalyn B. Irby, Juan Palop, Shantu Amin, Carmen Sanmartín, Arun K. Sharma. Identification of a novel quinoxaline-isoselenourea targeting STAT3 pathway as a potential melanoma therapeutic [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1166. doi:10.1158/1538-7445.AM2017-1166
Abstract 1169: mtTERT promoter as a target for treatment of glioblastoma
Authors: Bollam Saumya R. , Dhruv Harshil D. , Kang Hyun-Jin , Peng Sen , Gokhale Vijay , Hurley Laurence , Berens Michael
Published: July 2017

Approximately 86% of GBM tumors exhibit mutation at -124 or -146 bases upstream of the ATG start site in the transcription activating promoter region of Human telomerase reverse transcriptase (hTERT). Mutation in the promoter region of hTERT impairs repression, leading to overexpression of hTERT; inappropriate hTERT is associated with oncogenesis, tumor maintenance, and resistance to apoptosis. We surveyed long-term glioma cell lines and glioma PDX models for mt-hTERT; mRNA and protein expression of hTERT were assessed by qPCR and western blot. The -124 and -146 mutations are located in the major 5-12 G-quadruplex and result in misfolding of the silencer element and consequent over-expression of hTERT. Using a diverse small molecule library, we identified a small drug-like pharmacological chaperone (pharmacoperone) molecule, TG-4260, which binds to the 26 mer base-pair heteroduplex loop, which is the nucleation site for cooperative folding of the major 5-12 G-quadruplex. The chaperone effect of TG-4260 corrects DNA hTERT G-quadruplex misfolding resulting from the somatic mutations and restores the silencer function of the G-quadruplex thereby reducing hTERT activity. TG-4260 directly decreases the transcription activity of the WT and the −124, −124/125, −138/139, and −146 mutants to a similar extent and suppresses the downstream gene BCL2, which activates caspase-3 and produces cell-cycle arrest, leading to cell death. Finally, TG-4260 significantly inhibits telomerase and shortens telomere length after five days of treatment and induces a senescence-like phenotype. This is the first example of the use of a pharmacoperone molecule to correct the misfolding of a DNA G-quadruplex element resulting from mutations in an early folding intermediate. Finally, we screened GBM cell models against a novel small molecule inhibitor that interferes with mutated hTERT promoter and demonstrated that TG-4260 selectively suppresses glioma cell viability without affecting non-transformed normal human astrocytes.

Citation Format: Saumya R. Bollam, Harshil D. Dhruv, Hyun-Jin Kang, Sen Peng, Vijay Gokhale, Laurence Hurley, Michael Berens. mtTERT promoter as a target for treatment of glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1169. doi:10.1158/1538-7445.AM2017-1169
Abstract 1174: CT179 degrades the olig2 transcription factor in glioblastoma stem-like cells and prolongs survival
Authors: Alton Gordon R. , Beaton Graham , Knowles Susan , Stein Gregory , Kesari Santosh
Published: July 2017

Olig2 is a bHLH transcription factor that has been shown to be a key driver of glioblastoma (GBM) tumorigenesis. Olig2 is expressed in human tumor-derived glioma stem-like cells. A growing body of evidence suggests that glioma stem-like cells (GSCs) are more representative of their parent tumors when cultured under defined serum-free conditions with the mitogens epidermal growth factor (EGF) and fibroblast growth factor (FGF). Furthermore, recent research has indicated that human Proneural GSCs grown in vitro in PDGF are more tumorigenic in vivo. We have designed and synthesized a potent inhibitor of Olig2 that possesses all the necessary properties for clinical development as an important new GBM therapeutic. CT179 dose dependently causes the degradation of Olig2 in multiple GBM cell lines and this correlates to G2/M arrest and increased apoptosis. CT179 also induces the loss of expression of EGFR and PDGFR in human GSCs. CT179 achieves high concentrations in the CNS with a long duration of pharmacologic action. Furthermore, CT179 significantly extends survival of mice implanted orthotopically with patient-derived human tumor GSCs. Immunohistochemistry demonstrates a marked reduction of Olig2 positive cells in the tumor bearing animals. Together, these results indicate that CT179 has significant promise as a new therapeutic for the treatment of human GBM.

Citation Format: Gordon R. Alton, Graham Beaton, Susan Knowles, Gregory Stein, Santosh Kesari. CT179 degrades the olig2 transcription factor in glioblastoma stem-like cells and prolongs survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1174. doi:10.1158/1538-7445.AM2017-1174
Abstract 1177: Targeting NEDD8 to uncover an exceptional responder molecular subtype in glioblastoma
Authors: Hartman Lauren K. , Finlay Darren , Pan Peiwen , Kim Seungchan , Speyer Gil , Kiefer Jeff , Dhruv Harshil , Vuori Kristiina , Berens Michael
Published: July 2017

Neddylation is a post-translational mechanism that marks proteins for degradation through activity of NEDD8 Activating Enzyme (NAE). NAE blocks cullin-RING ligases from initiating proteosomal degradation of select substrates including cell cycle regulators and apoptosis modulators. MLN4924, or Pevonedistat, targets NAE and inhibits Neddylation and induces apoptosis in sensitive cells. We have discovered, in a cohort of glioblastoma PDX models, an exceptional responder to MLN4924 (GBM102). Most pertinently the effects we observe are in a PDX cultured as 3D neurospheres that more closely resemble the true tumor architecture, heterogeneity, and “stem-like” phenotype characteristic of tumor growth. We have leveraged RNAseq expression data from Cancer Cell Line Encyclopedia (CCLE) and Pevonedistat response data from The Cancer Therapeutics Response Portal (CTRP) to apply a network-based analysis to identify pathways enriched with differential dependencies between cell lines sensitive and non-sensitive to MLN4924. The analysis also identifies potential mediating genes that appear to play critical roles in such differential dependency networks. Identified differential networks and mediators provide insight for cellular mechanisms underlying drug response. Additionally, we also investigated the efficacy of MLN4924 against orthotopic glioma PDX models (GBM102 and GBM116) in vivo to validate our findings in vitro. Thus genomic characterization of patient samples may lead to the identification of a molecular signature which is associated with a subset of GBMs vulnerable to MLN4924. As the treatment options for GBM are extremely limited, this may highlight a novel alternative opportunity to treat a select fraction of patients with this aggressive disease.

Citation Format: Lauren K. Hartman, Darren Finlay, Peiwen Pan, Seungchan Kim, Gil Speyer, Jeff Kiefer, Harshil Dhruv, Kristiina Vuori, Michael Berens. Targeting NEDD8 to uncover an exceptional responder molecular subtype in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1177. doi:10.1158/1538-7445.AM2017-1177
Abstract 1181: Discovery and development of novel highly potent and selective inhibitors of USP19 using UbiPlex™
Authors: Gavory Gerald , O'Dowd Colin , Rozycka Ewelina , Dossang Anthony , Henderson Ashling , Hughes Caroline , Miel Hugues , Barker Oliver , Costa Joana , Hewitt Peter , McFarland Mary , Proctor Lauren , Harrison Tim
Published: July 2017

Over the past decade, protein ubiquitination has emerged as an important post-translational modification with regulatory functions in all important cellular processes. Deubiquitinating enzymes (DUBs) including ubiquitin specific proteases (USPs) are cysteine proteases that catalyse the de-ubiquitination of protein substrates including tumor suppressors and oncogenes, hence regulating their levels and/or function. As a result of their increasing implications in the etiology of numerous pathological conditions including cancer, DUBs are emerging as an attractive and promising target class for the development of 1st in class medicines with high therapeutic impact. However, despite 15 years of intense research DUBs have proved largely refractory to drug discovery efforts.

Herein, we further describe the application of Ubi-Plex™, our drug discovery platform for the identification and optimisation of DUB inhibitors. In particular, we will highlight the versatility and robustness of Ubi-Plex™ by describing the outcome of our focussed library screening, hit identification, hit validation and elaboration activities on USP19.

A series of novel, highly potent (e.g. IC50 < 10 nM) and reversible USP19 inhibitors have been identified. Further profiling has also demonstrated excellent selectivity against a large panel of DUBs and other non-related enzymes (e.g. kinases, proteases). These inhibitors are cell-permeable and exhibit potent target engagement in cells with EC50 values < 30 nM. Finally, we will describe our progress towards the development of lead molecules with drug-like properties with the aim to rapidly establish in vivo proof-of-concept studies.

In summary, this work further exemplifies the tractability of the DUB target family and reports the discovery and detailed profiling of the first highly potent and selective inhibitors of USP19. These molecules may provide opportunities for the development of new anticancer therapeutics as well as for the treatment of muscle wasting disorders including cachexia.

Citation Format: Gerald Gavory, Colin O'Dowd, Ewelina Rozycka, Anthony Dossang, Ashling Henderson, Caroline Hughes, Hugues Miel, Oliver Barker, Joana Costa, Peter Hewitt, Mary McFarland, Lauren Proctor, Tim Harrison. Discovery and development of novel highly potent and selective inhibitors of USP19 using UbiPlex™ [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1181. doi:10.1158/1538-7445.AM2017-1181
Abstract 1189: Enhanced YAP expression leads to EGFR TKI resistance in lung adenocarcinomas
Authors: Lee Ting-Fang , Tseng Yu-Chi , Wu Cheng-Wen
Published: July 2017

Epidermal growth factor receptor (EGFR) mutation is prevalently expressed in lung adenocarcinoma cases and acts as one of the major driving oncogenes. EGFR tyrosine kinase inhibitors (TKIs) have been used in patients with EGFR-mutant as an effective targeted therapy in lung adenocarcinoma, but drug resistance and tumor recurrence inevitably occurs. Recently, Yes-associate protein (YAP) has been reported to promote multiple cancer cell properties, such as promoting cell proliferation, EMT and drug resistance. This study investigated the roles of YAP in TKI-resistant lung adenocarcinoma. In TKI-sensitive cells, enhanced YAP expression leads to TKI resistant. Also, upregulated YAP expression and activation were detected in long term TKI-induced resistant cells. With reduced YAP expression using shRNA or YAP inhibitors, TKI-resistant cells become TKI-sensitive. Moreover, combined EGFR TKI and an YAP inhibitor statin, prolonged survival among lung cancer patients analyzed by Taiwan National Health Insurance Research database. These observations revealed the importance of YAP in promoting TKI-resistance and combined YAP inhibition can be a potential therapy delaying the occurrence of TKI-resistance in lung adenocarcinoma.

Citation Format: Ting-Fang Lee, Yu-Chi Tseng, Cheng-Wen Wu. Enhanced YAP expression leads to EGFR TKI resistance in lung adenocarcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1189. doi:10.1158/1538-7445.AM2017-1189
Abstract 1192: Regorafenib (Stivarga®) reverses BCRP-mediated multidrug resistance in vitro and in vivo
Authors: Zhang Yun-Kai , Wang Yi-Jun , Zhang Guan-Nan , Zhang Wen-Ji , Wei Meng-Ning , Shi Zhi , Chen Zhe-Sheng
Published: July 2017

Overexpression of breast cancer resistance protein (BCRP) has been shown to produce multidrug resistance (MDR) in various kinds of cancers, such as breast, colon, lung and ovarian cancers. Regorafenib, an oral multi-kinase inhibitor, was found to have inhibitory effects on BCRP-mediated MDR both in vitro and in vivo. Regorafenib significantly sensitized BCRP-overexpressing cancerous cells to BCRP substrates by increasing their intracellular accumulation. There are no significant changes in the expression level or the subcellular distribution of BCRP in the cells exposed to regorafenib. Our mechanism studies revealed that regorafenib inhibited the ATP-driven efflux function of BCRP. Our induced-fit docking and molecular dynamics simulations suggested the existence of strong and stable interactions between regorafenib and BCRP protein. Animal study revealed that the combination of regorafenib and topotecan resulted in great inhibitory effects on the growth of S1-M1-80 xenograft tumors. Regorafenib significantly increased the intratumoral concentration of topotecan but had no significant effects on topotecan plasma concentration. In conclusion, our study indicated that regorafenib could be useful in combating multidrug resistance in cancer treatments.

Citation Format: Yun-Kai Zhang, Yi-Jun Wang, Guan-Nan Zhang, Wen-Ji Zhang, Meng-Ning Wei, Zhi Shi, Zhe-Sheng Chen. Regorafenib (Stivarga®) reverses BCRP-mediated multidrug resistance in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1192. doi:10.1158/1538-7445.AM2017-1192