bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract B189: The Nedd8-activating enzyme inhibitor MLN4924 combined with rituximab induces additive/synergistic anti-tumor activity in preclinical non-Hodgkin's lymphoma models
Authors: Tou Derek Liqiang , Traore Tary , Pickard Michael , Pulukuri Sai , Manfredi Mark , Petruzzelli Lilli , Berger Allison , Smith Peter G.
Published: June 2012

MLN4924 is a novel, small molecule inhibitor of Nedd8-activating enzyme (NAE) that is currently in Phase I clinical trials in hematologic malignancies. We have previously described the pre-clinical anti-tumor activity of MLN4924 in human xenograft models of hematological and solid tumors. Rituximab is an anti-CD20 monoclonal antibody that has been established as part of the standard of care for the treatment of non-Hodgkin's lymphoma (NHL). In the present study, we investigated whether a combination of MLN4924 and Rituximab may act in a complementary manner in pre-clinical models of NHL. We utilized models of ABC-like Diffuse Large B-cell Lymphoma (ABC-like DLBCL, OCI-Ly10 cells) dependent on NF- B signaling for survival and Germinal Center B-cell like DLBCL (GCB-like DLBCL, OCI-Ly19 cells) that are not dependent on NF-κB signaling for survival. In vivo administration of MLN4924 to mice bearing xenograft tumors of OCI-Ly10 and OCI-Ly19 resulted in a pharmacodynamic response of NAE pathway inhibition. In both models, a single dose of MLN4924 resulted in a dose-dependent inhibition of NAE and stabilization of Cullin Dependent Ligase substrates including Nrf-2 and pI Bα.

MLN4924 induced antitumor activity that was dose-dependent in both models. In the OCI-Ly10 model co-administration of MLN4924 (10 or 3 mg/kg) and Rituximab (0.3 or 1 mg/kg) induced either synergistic or additive anti-tumor activity (P>0.05). The combination of 10 mg/kg MLN4924 and 1 mg/kg Rituximab resulted in 3 partial and 7 complete responses. In the OCI-Ly19-luc disseminated lymphoma model combining MLN4924 (10–30 mg/kg) with Rituximab resulted in additive tumor growth inhibition. The mean survival endpoint was significantly longer (p=<0.01) in the combination group when compared to the single agent group. Importantly, all animals in the MLN4924 (60 mg/kg) and Rituximab (10 mg/kg) combination group were still alive 100 days after treatment ended. All doses and regimens were well tolerated.

The results of these studies demonstrate that combination treatment with MLN4924 and Rituximab resulted in additive and/or synergistic reduction in tumor burden in the OCI-Ly10 and OCI-Ly19 models. In addition, these data provide the rationale for future clinical evaluation of MLN4924 in combination with Rituximab in lymphoma.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B189.
Abstract B208: Phase I study of angiotensin-(1–7), an endogenous antiangiogenic hormone: Clinical, pharmacokinetic, and biomarker findings
Authors: Petty William Jeffrey , Miller Antonius A. , McCoy Thomas P. , Gallagher Patricia E. , Tallant E. Ann , Torti Frank M.
Published: June 2012

Background: Angiotensin-(1–7) [Ang-(1–7)] is an endogenous peptide hormone of the renin-angiotensin system with anti-proliferative and anti-angiogenic properties. The primary objective of this study was to establish the recommended phase II dose of Ang-(1–7) for treating patients with advanced cancer. Secondary objectives were to assess toxicities, pharmacology, clinical responses, and potential biomarkers of anti-angiogenic effects.

Methods: Patients with advanced solid tumors refractory to standard therapy were eligible. Patients were treated with escalating doses of Ang-(1–7) in cohorts of three patients. Ang-(1–7) was administered by subcutaneous injection once daily for five consecutive days on a three week cycle. Tumor measurements were performed every two cycles and treatment was continued until disease progression or unacceptable toxicity. Blood samples were obtained for pharmacokinetic and plasma biomarker analyses.

Results: Eighteen patients were enrolled. Serious adverse events possibly related to treatment included stroke, reversible cranial neuropathy, and deep vein thrombosis. Other toxicities were mild. One patient developed a 19% reduction in tumor measurements. Three additional patients demonstrated clinical benefit with stabilization of disease lasting more than three months. One patient with stable disease also demonstrated cystic tumor changes, and one patient with stable disease also demonstrated minor PSA reductions after each cycle. In patients with clinical benefit, Ang-(1–7) administration resulted in a dose-dependent decrease in plasma placental growth factor (PlGF) (P = .04) on day 1. No change in plasma PlGF occurred in patients without clinical benefit on day 1 (P = .25). On day 5, PlGF levels remained lower in patients with clinical benefit compared to patients without clinical benefit (P = .04).

Conclusions: Ang-(1–7) is a first-in-class anti-angiogenic drug targeting the mas receptor. Clinical benefit is associated with a reduction in plasma PlGF levels following Ang-(1–7) treatment. The recommended phase II dose is 400 mcg/kg for this administration schedule.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B208.
Abstract B213: Pharmacokinetics (PK) and efficacy of axitinib in patients (pts) with sorafenib-refractory metastatic renal cell carcinoma (mRCC)
Authors: Dutcher Janice , Garrett May , Wilding George , Stadler Walter M. , Pithavala Yazdi , Kim Sinil , Tarazi Jamal , Rixe Olivier , Rini Brian I.
Published: June 2012

Background: Axitinib (AG-013736) is an oral, potent, and selective inhibitor of vascular endothelial growth factor receptors 1, 2, 3. The objectives of this analysis were to assess the impact of food, gender, race, weight, age, and disease status on axitinib PK and to explore the relationship between PK, diastolic blood pressure (dBP), and clinical efficacy in sorafenib-refractory mRCC pts. A relationship has been previously reported in refractory mRCC pts.

Methods: Pooled PK data were analyzed using nonlinear mixed-effects modeling to estimate population PK parameters (mean and inter-individual variability; Rixe et al. ASCO Annual Meeting 2009; abstract 5045). Efficacy data from sorafenib-refractory mRCC pts (n=59) were included in the PK/pharmacodynamic analysis. Mean steady-state area under the plasma concentration-time curve (AUC) at the end of cycle 1 and dBP during axitinib therapy were utilized as predictors of clinical efficacy in the mRCC pts using logistic regression and Kaplan-Meier survival analyses.

Results: Median overall survival (OS) for sorafenib-refractory mRCC pts with an AUC below the median (662 ng·hr/mL; n=29) was 42 weeks vs 84 weeks (P<0.05) for pts with an AUC above the median (n=30). Median OS for sorafenib-refractory mRCC pts with at least 1 dBP measurement ≥90 mmHg (n=29) during axitinib therapy was 88 weeks vs 42 weeks for pts without any dBP ≥90 mmHg (n=30; P<0.05). Furthermore, logistic regression showed that for every 100 ng·hr/mL increase in axitinib AUC, there was a 1.24-fold increase in the odds of a partial response (PR). BP was the stronger predictor vs PK, with a 2.41-fold increase in the odds of a PR with every 10 mmHg increase in dBP.

Conclusions: Increased exposure to axitinib and dBP ≥90 mmHg during axitinib therapy are associated with greater probability of a PR and longer median OS in sorafenib-refractory mRCC pts. These data support an ongoing, pivotal, phase III trial in previously-treated mRCC that incorporates a dosetitration scheme based on patient tolerance and BP.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B213.
Abstract B214: Use of a pharmacokinetic model derived from early clinical studies to assess the relevance of covariates on cilengitide pharmacokinetics
Authors: Zuehlsdorf Michael , Bhattaram Venkatesh Atul , Kroesser Sonja , Derendorf Hartmut , Kovar Andreas
Published: June 2012

Background: Cilengitide is a selective competitive inhibitor of αvβ3 and αvβ5 integrins. It demonstrates anti-angiogenic, direct anti-tumor and anti-migratory properties and is under investigation for use in treating glioblastoma, cancer of the head and neck, NSCLC and other indications. The primary objective of this analysis was to characterize the population pharmacokinetic behavior of cilengitide from data obtained from three studies in patients with advanced solid cancer, NSCLC or advanced unresectable pancreatic cancer using a nonlinear mixed effects modeling technique.

Methods: A stepwise approach was used on the data (992 concentration time points from 136 patients) beginning with exploratory analysis to verify the database for the three studies and target covariate relationships. A two compartment pharmacokinetic structural model was developed in NONMEM® to describe the concentration-time profile of cilengitide using initial parameter estimates determined from preliminary analysis using KINETICA®. Main individual covariates were tested to estimate their impact on PK parameters using two procedures: i) a stepwise selection procedure in NONMEM and ii) generalized additive modeling with XPOSE® software. The model was validated by testing the stability of the base and final model via a bootstrap procedure (1000 replicate data sets generated from the original data set).

Results: A pharmacokinetic model was developed and validated for cilengitide from data obtained from three different studies. Study was not a significant covariate for the model. Estimated pharmacokinetic parameters for the structural model were 2.79 L/h/m2 for CL (clearance from central compartment), 6.75 L/m2, for V1 (volume of distribution for central compartment), 1.3 L/h/m2 for Q (intercompartmental clearance) and 3.85 L/m2 for V2 (volume of distribution for peripheral compartment). The half-life was estimated as 0.9 h and 3.8 h for and -phase. The model PK parameters are consistent with individual study derived PK parameters (2 to 4 L/h/m2 for mean systemic clearance (CL), 0.84 to 3.36 for renal clearance and 3 to 5 hours for terminal half-life).

From the covariates analyzed (age, weight, BSA, albumin, bilirubin, serum creatinine, aspartate amino transferase, alanine amino transferase, alkaline phosphatase, hepatic status, gender and study) only weight and body surface area were highly correlated (r=0.95, p<0.01). Although the albumin and bilirubin covariates were statistically significant for the final model, their inclusion is not clinically relevant based on the information obtained from the studies.

Information generated by using the model to predict cilengitide profiles in different patient populations can speed identification of optimized dosing regimens.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B214.
Abstract B250: Clinical benefit of lapatinib-based therapy in patients with HER2-positive breast tumors expressing p95HER2
Authors: Scaltriti Maurizio , Chandarlapaty Sarat , Prudkin Ludmila , Aura Claudia , Jimenez Jose , Angelini Pierdavide , Ellis Cathrine , Gagnon Robert , Rosen Neil , Baselga Jose
Published: June 2012

Purpose: A subgroup of HER2 overexpressing tumors also express p95HER2, a truncated fragment of the HER2 receptor that lacks the extracellular domain, retains kinase activity and correlates with intrinsic trastuzumab resistance. We tested the hypothesis that the small molecule lapatinib, an EGFR/HER2 dual tyrosine kinase inhibitor, would be active in these tumors. We studied the correlation between p95HER2 expression and response to lapatinib, both in preclinical models and in the clinic [lapatinib monotherapy (Study EGF20009) or lapatinib in combination with capecitabine (Study EGF100151)].

Patients and Methods: Expression of p95HER2 in primary tumors was evaluated by immunofluorescence and correlated with clinical benefit rate (complete response + partial response + stable disease ≥ 24 weeks) and progression-free survival using logistic regression and Cox-proportional hazard models.

Results: Lapatinib was efficacious in inhibiting tumor growth and HER2 downstream signaling of p95HER2 expressing tumors in two different animal models. In human samples, expression of p95HER2 was evaluable in 76% (105/138) and 56% (223/399) of patients from EGF20009 and EGF100151 studies, respectively. The percentage of p95HER2 positive patients was 20.5% in the EGF20009 study and 28.5% in the EGF100151 study. In neither study there was a statistically significant difference in progression-free survival between p95HER2-positive and p95HER2-negative patients. Similarly, in both studies the clinical benefit rate was not significantly associated with p95HER2 expression.

Conclusions: Lapatinib as a monotherapy or in combination with capecitabine is equally effective in patients with p95HER2-positive and p95HER2-negative HER2-positive breast tumors.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B250.
Abstract B252: Identification of a new class of highly potent and selective c-Met kinase inhibitors
Authors: Blaukat Andree , Bladt Friedhelm , Dorsch Dieter , Fittschen Claus , Friese-Hamim Manja , Graedler Ulrich , Meyring Michael , Rautenberg Wilfried , Schadt Oliver , Stieber Frank
Published: June 2012

The role of the receptor tyrosin kinase c-Met in tumor progression and metastasis has been shown in preclinical studies and in early clinical settings. Several c-Met inhibitors with different selectivity profiles are currently in preclinical/clinical investigation and might provide effective cancer therapeutics in the future.

A biochemical HTS run using the recombinant kinase domain of c-Met enabled us to identify N-(3-(3,6-Dihydro-5-(3,4-dimethoxyphenyl)-2-oxo-2H-1,3,4-thiadiazin-3-ylmethyl)-phenyl)-carbaminic acid-(3-(N,N-diethylamino)-propylester) representing as new chemical class of kinase inhibitors. This HTS hit inhibited c-Met in vitro kinase activity and HGF-induced c-Met phosphorylation in A459 lung cancer cells with IC50 values well below 1 µM. The analysis of co-crystal structures defined the molecular requirements for potency and selectivity and guided the subsequent chemical optimization. As a result of the lead optimization process, two candidate compounds with distinct pharmacological properties were synthesized, EMD 1214063 and EMD 1204831. Both compounds are highly potent and efficient inhibitors of c-Met in vitro kinase activity and c-Met auto-phosphorylation induced in vitro by HGF stimulation or by c-Met overexpression. Both compounds displayed an exquisite selectivity profile when tested in vitro against a panel of more than 250 potential off-targets, including kinases, GPCRs, ion channels, transporters and various enzymes.

EMD 1214063 and EMD 1204831 exhibited excellent anti-tumor activity in vivo in a variety of xenograft models, including U87-MG glioblastoma cells (autocrine HGF production), TPR-Met-transformed mouse fibroblasts (oncogenic Met fusion protein) or Hs746T gastric and EBC-1 lung cancer cells (c-Met gene amplification and HGF-independent activation).

In c-Met-driven models complete regressions were observed with doses as low as 6 mg/kg/d administered per os. PK/PD analysis revealed efficient, dose- and time-dependent inhibition of c-Met phosphorylation, reduction of IL-8 and cyclin D1 expression as well as an induction of the cell cycle inhibitor p27. The pharmacodynamic effects of EMD 1214063 were longlasting and allowed various schedule variations without compromising its anti-tumor activity, while c-Met inhibition by EMD 1204831 was rather transient, allowing optimal anti-tumor activity when the compound was applied once or twice daily.

The profile of EMD 1214063 and EMD 1204831 including synthesis, structure activity relationships, X-ray structures and a comprehensive pharmacological in vitro and in vivo characterization will be presented. Furthermore, potential pharmacodynamic and predictive biomarkers will be discussed.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B252.
Abstract B255: Discovery and validation of a novel class of small molecule inhibitors of the CDC7 kinase: Modulation of tumor cell growth in vitro and in vivo
Authors: Frattini Mark G. , Shum David , O'Dwyer Kristen , Brentjens Renier , Maslak Peter , Heaney Mark , Jurcic Joseph , Djaballah Hakim , Kelly Thomas
Published: June 2012

High throughput screening of compounds comprising the Memorial Sloan Kettering chemical library resulted in several confirmed hits against the recombinant Cdc7:Dbf4 heterodimeric kinase, a key regulator in the initiation of DNA replication and the G1 to S phase transition. Chemoinformatic analysis of the hits revealed an enrichment in one chemical cluster made up of several naturally occurring compounds, of which the most potent compound, CKI-7, was selected for further investigation. First, CKI-7 was found to be a non competitive inhibitor for ATP and prompted us to prolife it against a panel of 200 known kinases in order to assess its selectivity profile. The results were as predicted and very few kinases were specifically affected. Second, CKI-7 cytotoxic activity was assessed against a panel of well established cancer cell lines representing both hematopoietic and solid tumor malignancies as well as against a panel of primary hematopoietic cells derived from leukemia patients (both chemotherapy naive and relapsed/refractory samples) and was found to be a very effective agent with potencies in the low nanomolar range. Subsequent studies using an isogenic pair of cell lines with one over expressing the Bcl_xL anti-apoptotic protein further confirmed the induction of the intrinsic apoptotic pathway via caspase-3 activation in the absence and attenuation of the activity in the presence of Bcl_xL. This was further demonstrated through standard cell cycle synchronization studies revealing that exposure to the Cdc7 inhibitor results in an S phase arrest, cell cycle dependent caspase-3 activation, and apoptotic cell death. This cell death is the direct result of Cdc7 kinase inhibition by CKI-7 as demonstrated using a Cdc7 substrate biomarker assay. Third, the physicochemical properties of this class of naturally occurring compounds also prompted us to investigate their effect on several multidrug resistence (MDR) over-expressing cell lines. We found that CKI-7 was not a substrate for the efflux pumps demonstrating that this novel compound can overcome a major mechanism of chemotherapy resistence in human tumor cells. Based of the above observations, in vivo dose-dependent anti-tumor activity of CKI-7 was subsequently demonstrated in a SCID-Beige mouse systemic tumor model utilizing a recently isolated Philadelphia chromosome positive acute lymphoblastic leukemia cell line (PhALL3.1) in addition to melanoma and non small cell lung cancer xenograft models. Taken together, our data confirm that Cdc7 is a new promising target for cancer therapy, and that the newly discovered inhibitor CKI-7, a naturally occurring selective small molecule inhibitor of this enzyme, is an equally promising novel cancer therapeutic agent.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B255.
Abstract B272: The novel PIM kinase inhibitor SGI-1776 significantly enhances the preclinical activity of sunitinib in renal cell carcinoma
Authors: Mahalingam Devalingam , Medina Ernest , Swords Ronan T. , Kelly Kevin R. , Bearss David , Choy Gavin , Taverna Pietro , Carew Jennifer S. , Giles Francis J. , Nawrocki Steffan T.
Published: June 2012

The PIM kinases (PIM1, PIM2, and PIM3) are constitutively active serine/threonine kinases that promote tumorigenesis in mouse models and are associated with drug resistance. Upregulation of PIM kinase expression has been reported in many malignancies including renal cell carcinoma (RCC), suggesting that inhibition of PIM kinase activity may be an attractive therapeutic strategy. SGI-1776 is a novel orally available small molecule inhibitor of PIM kinase activity that is currently in Phase I clinical trials. We hypothesized that inhibition of PIM kinase activity would reduce the viability of RCC cells and enhance the activity of the multi-targeted receptor tyrosine kinase (RTK) inhibitor sunitinib. Cell viability and apoptosis assays demonstrated that SGI-1776 possessed significant in vitro activity in a panel of RCC cell lines. One of the mechanisms by which the PIM kinases have been reported to inhibit apoptosis is by phosphorylating the BH3-only protein Bad to abrogate its pro-apoptotic function. Accordingly, SGI-1776-mediated apoptosis was associated with decreased levels of the phosphorylated form of Bad. Moreover, targeted knockdown of Bad expression significantly decreased sensitivity to SGI-1776 indicating that Bad is an important mediator of the anticancer activity of this agent. Treatment with SGI-1776 also led to a markedly decrease in phosphorylated and total c-Myc levels and enhanced the activity of sunitinib in RCC cells. The addition of sunitinib to SGI-1776 further reduced c-Myc expression. Silencing of the gene suggested that c-Myc plays a significant role in sensitivity to the SGI-1776/sunitinib combination. To further evaluate this drug combination, Caki-1 and 786-O RCC xenografts were established in nude mice and they were treated orally with SGI-1776, sunitinib, or the combination. The SGI-1776/sunitinib combination significantly reduced tumor burden in both xenograft models compared to single agent therapy and was very well tolerated. Analysis of the tumors revealed that the drug combination strongly decreased tumor proliferation and induced apoptosis as measured by PCNA and TUNEL immunohistochemistry, respectively. These data indicate that PIM kinase signaling has a significant role in the biology of RCC and warrants further investigation.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B272.
Abstract B35: Validation of a multiplex method for detection of several oncosignaling proteins with potential utility for assessment of pharmacodynamic activity of hsp90 inhibitors
Authors: Hipolito Lori , Dakappagari Naveen , Stenzel Daniel , Pierce Laura , Timple Noelito , Ibanez Gerardo , Lundgren Karen , Harris Sarah , Tangri Shabnam
Published: June 2012

Biomarkers are increasingly being used in early phase clinical trials not only to determine pharmacodynamic activity but also as surrogate end points of clinical efficacy. BIIB021 is a synthetic small molecule that inhibits the activity of Hsp90, a molecular chaperone involved in the folding of multiple oncogenic signaling proteins. Treatment of tumor models and cancer patients with BIIB021 resulted in proteosomal degradation of key cancer survival proteins e.g., AKT, RAF, IGF-1R, ER and HER-2. BIIB021 is currently undergoing Phase I/II testing in GIST, Breast Cancer and Solid tumors. We are exploring robust methods for assessing multiple signaling markers with an objective of using them to confirm inhibition of Hsp90 activity and support dose/schedule finding studies. To that end, we have evaluated the utility of a sensitive multiplex assay on the Meso Scale Discovery (MSD) platform. This platform measures the levels of total and phosphorylated proteins of the MAPK and AKT signaling pathways. Peripheral blood mononuclear cells from healthy, breast and prostate cancer patients were treated ex vivo with BIIB021 and the levels of multiple signaling proteins were determined in the MSD assay. A significant decrease in the AKT family of signaling proteins was observed in all of the donors tested, while up to 75% of the subjects showed a marked reduction in the MAPK family of proteins over a period of 24hrs. The depletion of the similar oncosignaling proteins by BIIB021 was also confirmed in mouse models of human breast cancer and in vitro studies using the MSD platform1. Furthermore, to support the future development of BIIB021 in oncology, the multiplex assay will be validated for various clinical parameters (i.e., Quantitation range, reproducibility, accuracy, precision, linearity, longitudinal variability, and stability). We anticipate a rationally developed and rigorously validated multiplex assay measuring key signaling proteins involved in the survival of tumor cells would fully support the clinical development of BIIB021 and a wide range of anti-cancer agents affecting the AKT/MAPK pathways.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B35.
Abstract B42: ATM deficiency sensitizes gastric cancer cells to the PARP inhibitior olaparib
Authors: Guo Xiaoning , Shen Dihan , Cheng Wenxiang , Bai Yu , Ni Xing-Zhi , Shen Dan-ping , Zhang Shirong , Xie Liang , Knights Charlotte , Lau Alan , O'Connor Mark , Yin Xiaolu , Warford Anthony , Gu Yi
Published: June 2012

Ataxia telangiectasia mutated (ATM) is a protein kinase that regulates cell-cycle checkpoints, DNA repair and recombination (1). It has been shown that ATM interacts with and regulates NBS1 and BRCA complex which is essential for the homologous recombination (HR) repair in response to the DNA double-strand break (DSB) damage (2). These observations suggest that tumor cells with defective ATM expression or activity subsequently leading to HR deficiency are likely more sensitive to the targeted therapeutic/chemotherapeutic agents that cause the accumulation of DNA DSBs during replication. To test this, we studied the growth inhibitory effects of olaparib (AZD2281; KU-0059436) and SN-38 (the active metabolite of Irinotecan) on gastric cancer (GC) cells with reduced ATM expression. Olaparib is a potent oral inhibitor of poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP), which has selective antitumor activity in cancers associated with BRCA1 and BRCA2 mutations (3). Our study here showed that 6 out of 7 GC cell lines with low or no expression of ATM are sensitive to olaparib inhibition with IC50s ≤ 1uM as measured by clonogenic survival assays. In contrast, the majority of other GC cell lines positive for ATM expression (11 out of 13) are less sensitive (1uM < IC50 ≤ 1.5uM) or resistant (IC50 > 1.5uM) to olaparib with only 2 of 13 lines sensitive. Similar correlation was also observed in these GC cell lines between reduced ATM expression and sensitivity to SN-38 treatment. In addition, combination of olaparib and SN-38 had a synergistic and selective inhibitory effect on cell growth of GC cells with low/no expression of ATM. These data suggest that loss of ATM in GC cell can sensitize their cellular response to olaparib or/and SN-38. Next, we asked whether this finding has clinical relevance in GC therapy. The tumor and tumor adjacent tissue specimens from more than 100 patients with gastric cancer were analyzed for ATM expression by immunohistochemistry. 22% (24/111) of the gastric tumor specimens were found stained ATM negative while the negative rate in the adjacent tissues was only 4% (1/26). These results suggested that loss of ATM expression is frequently associated with gastric tumorigenesis. Loss of ATM function may serve as an important tumor biomarker in GC and a PARP inhibitor as monotherapy or in combination with chemotherapy provides a promising therapeutic in this disease segment.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B42.
Abstract B53: Assessment of the effect of food on the oral bioavailability and assessment of diurnal variation in the pharmacokinetics of linifanib
Authors: Gupta Neeraj , Yan Zhiwu , LoRusso Patricia , Ricker Justin L. , Carlson Dawn M. , Pradhan Rajendra
Published: June 2012

Background: Linifanib (ABT-869) is a novel orally active and selective inhibitor of vascular endothelial growth factor and platelet derived growth factor families of receptor tyrosine kinases. Efficacy was observed at 0.25 mg/kg dose in 3 Phase II studies in patients with hepatocellular carcinoma, non-small cell lung cancer and renal cell carcinoma.

Methods: This is an ongoing Phase 1, single- and multiple-dose, openlabel, randomized, multicenter, crossover study. Patients (N=12) with advanced or metastatic solid tumors are randomly assigned to one of the two Groups (N=6 per group): Group I (oral administration of 0.25 mg/kg linifanib under fasting conditions on Day (D)1 followed by non-fasting conditions on D7 and alternating multiple doses in the AM or PM under fasting conditions), Group II (oral administration of 0.25 mg/kg linifanib under non-fasting conditions on D1 followed by fasting on D7 and alternating multiple doses in the PM or AM under fasting conditions). PK samples are collected at various time points after single dose on D1 and D7 for food effect and multiple doses on D21 and D31 for diurnal variation assessment. The samples were analyzed for plasma concentration using LCMS/MS. Maximum observed plasma concentration (Cmax), time to Cmax (Tmax) and total area under the concentration-time curve (AUC) or from 0 to 24h were determined by non-compartmental analysis using WinNonlin Professional V. 5.2.

Results: Based on preliminary data from 9 patients, there appears to be a negative effect of food on linifanib PK (a decrease of 43% in Cmax and 20% in AUC). AM dosing appears to result in higher exposures than PM dosing (an increase of 69% in Cmax and 58% in AUC) based on data from 5 patients. Terminal half-life of linifanib was estimated to be approximately 1 day.

Conclusion: Preliminary results show that linifanib exposures may be influenced by food and time of dosing.

Linifanib (single dose) for food effect assessment# Regimen Tmax (h) Dose-normalized Cmax (µg/mL/mg) Dose-normalized AUCinf (µg*hr/mL/mg) A: Fasting (N=9) 1.8±0.4 0.019±0.006 0.44±0.12 B: Non-fasting (N=9) 4.9±2.1 0.011±0.002 0.36±0.12 Ratio B/A (point estimate)* - 0.574 0.799 90% confidence interval for B/A - 0.505–0.653 0.725–0.880 Linifanib (multiple dose) for diurnal variation assessment Regimen Tmax (h) Dose-normalized Cmax (µg/mL/mg) Dose-normalized AUC24 (µg*hr/mL/mg) A: AM (N=5) 2.4±0.5 0.022±0.005 0.30±0.06 B: PM (N=6) 4.0±1.1 0.013±0.006 0.19±0.06 * Antilogarithm of the difference (B-A) of the least squares means for logarithms. # Mean±SD

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B53.
Abstract B7: TSU-68 suppresses the progression of malignant pleural mesothelioma cells in SCID mice by inhibiting angiogenesis
Authors: The Van Trung , Kuramoto Takuya , Goto Hisatsugu , Kakiuchi Soji , Taniguchi Tetsuo , Sekido Yoshitaka , Nishioka Yasuhiko , Sone Saburo
Published: June 2012

Background: Malignant pleural mesothelioma (MPM) is a highly lethal neoplasm, for which the therapeutic options are limited. Pemetrexed combined with cisplatin, which has been approved, still has poor overall outcome. Molecular targeted therapies represent a promising strategy for overcoming limitation in therapy of malignant neoplasm including MPM. TSU-68 (SU6668), a tyrosine kinase inhibitor targeting VEGFR2, PDGFRβ and FGFR1 can inhibit the growth of various tumors. However, the efficacy of TSU-68 on MPM has not been investigated.

Purpose: Investigate the therapeutic efficacy of TSU-68 on the progression of human MPM cells in an orthotopical implantation model.

Method: Y-MESO-14 cells (expressing high level of VEGF and low level of bFGF) and MSTO-211H cells (expressing low level of VEGF and high level of bFGF) were orthotopically inoculated into thoracic cavities of SCID mice. From day 7 after inoculation, mice were treated with either TSU-68 (200mg/kg/day) or vehicle for two weeks. At the end of treatment, mice were sacrificed for analyzing the characteristics of thoracic tumors and pleural effusion.

Result: In both cells, TSU-68 inhibited the tumor size, pleural effusion volume and vessel density in the tumor compared to control group. Furthermore, TSU-68 inhibited the proliferation of endothelial cells stimulated by VEGF, bFGF, or supernatant of MPM cell culture media in vitro.

Conclusion: TSU-68 has anti-tumor activity for MPM progression. via inhibiting angiogenesis These findings suggest that TSU-68 may be clinically useful to improve the treatment outcome of MPM.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B7.
Abstract B71: Chemosensitization to bleomycin conferred by a constitutive activation of IKK pathway in viral FLIP expressing cells
Authors: Noguchi Kohji , Masuda Yuri , Katayama Kazuhiro , Mitsuhashi Junko , Sugimoto Yoshikazu
Published: June 2012

Chemosensitivity to anticancer drugs is influenced by various gene expressions in a variety of cancer cell types. Identification of gene affecting chemotherapeutic efficacy should contribute to design of optimized therapeutic strategy for cancer. IkappaB kinase (IKK) complex activates NF-kappaB pathway, and NF-kappaB activation causes complicated effects on cell proliferation, survival, apoptosis and chemosensitivity through induction of various gene expressions such as antiapoptotic genes. To address an effect of IKK complex activation on cancer cell chemosensitivity, viral FLIP (vFLIP/K13/ORF71) encoded by Kaposi sarcoma-associated virus/Human herpes virus-8 (KSHV/HHV-8) was stably expressed in HEK293 cells. Viral FLIP activates IKK complex by a direct binding with IKKgamma, and the sensitivity of these vFLIP-expressing cells was examined by MTT assay with various anticancer drugs. The results indicated that vFLIP expression induced selective sensitization to bleomycin and another bleomycin-related reagents peplomycin. Regarding bleomycin sensitivity, bleomycin hydrolase inactivates bleomycin and decreases sensitivity to it. Interestingly, we found that vFLIP expression disturbed subcellular localization of bleomycin hydrolase although bleomycin hydrolase expression level was not affected. These observations suggest for the first time that an activation of IKK-pathway is a novel modulator of bleomycin chemosensitivity.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B71.
Abstract B8: A phase I pharmacokinetic (PK) study of TSU-68 plus S-1 and oxaliplatin (SOX) in patients with metastatic colorectal cancer (mCRC) treated with prior chemotherapy
Authors: Shin Sang Joon , Ahn Joong Bae , Jeung Hei-Cheul , Rha Sun Young , Roh Jae Kyung , Ahn Jung Ryun , Kim Chan , Chung Hyun Cheol
Published: June 2012

Background: TSU-68 is a novel oral multiple tyrosine kinase inhibitor that inhibits VEGFR-2, FGF and PDGF receptors. Since TSU-68 inhibit angiogenesis pathway which is important to tumor growth and metastasis in human colorectal cancer, we conducted a phase I study to evaluate the safety, tolerability and PK of TSU-68 plus S-1 and oxaliplatin (SOX) in patients with metastatic colorectal cancer (mCRC) treated with prior chemotherapy. Methods and Materials: ECOG PS 0 or 1 patients with mCRC were treated with TSU-68 400 mg/day (Level 1) or 800 mg/day (Level 2) on Days 1–21, S-1 70 mg/m2 on Days 1–14 with one week rest and oxaliplatin 130 mg/m2 IV on Day 1 repeated every 3 week. The dose escalation of TSU-68 was not done more than Level 2 based on the results of phase I studies of TSU-68 alone in Japan.

Results: Eleven patients were enrolled in the study. Of 11 patients, 2 patients were excluded from DLT assessment because both patients withdrew the written informed consent (IC) without a DLT during cycle 1. Of 9 evaluable patients, initial 3 patients in Level 1 experienced no DLT. Of 3 patients in Level 2, two patients experienced a DLT (one patient: grade 3 hiccup and grade 3 rash, another one: grade 2 neutropenia which prevented the initiation of the next cycle within 14 days). According to the protocol, additional 3 evaluable patients were enrolled in Level 1, and experienced no DLT. The MTD and RD of TSU-68 in combination with SOX was 400mg. Common adverse drug reactions (ADRs) in cycle 1 included peripheral sensory neuropathy (91%), nausea (82%), anorexia (82%), fatigue (46%), vomiting (36%) and diarrhoea (36%). No patient exhibited grade 4 ADR and treatment related death. Partial response was observed in 2 patients treated with prior chemotherapy. Median PFS was 218 days. TSU-68 plasma concentrations, Cmax and AUC0-t in Level 1 were higher than those in Level 2. There was no appreciable effect of administered TSU-68 on the PK of S-1 components (FT, CDHP and Oxo) and oxaliplatin-derived platinum.

Conclusions: Administration of TSU-68 in combination with SOX is generally well tolerated. The MTD and RD of TSU-68 in this study was 400mg. A multi-institutional phase II study of TSU-68 at 400mg/day in combination with SOX is planned.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B8.
Abstract B80: HSP90 inhibitor SNX-2112 and prodrug SNX-5422 (PF-04929113) inhibit key signal pathways Akt, Src and STAT3 and reactivate tumor suppressor p53 in head and neck cancer
Authors: Friedman Jay A. , Hu Michael , Arun Pattatheyil , Skillings Jamey , Chen Zhong , Van Waes Carter
Published: June 2012

Purpose: Heat shock 90 (Hsp90) is a molecular chaperone that interacts with and stabilizes many client substrates involved in modulating cell proliferation, survival, and apoptosis. Natural product Hsp90 inhibitors, such as benzoquinone ansamycins and their derivatives (i.e. geldanamycin, 17AAG), degrade oncogene and signal protein clients of Hsp90 and possess anti-tumor activity. Due to the limited solubility and hepatotoxicity caused by these agents, other Hsp90 inhibitors with a more favorable profile have been intensely sought after. In this study we investigated the biological activity of a synthetic small molecule inhibitor of Hsp90, SNX-2112, or the orally available prodrug SNX-5422 (PF-04929113), in human head and neck squamous cell carcinomas (HNSCC).

Experimental Design: The effects of SNX-2112 on cellular proliferation and Hsp90 client signal molecules, p53, and p53-targets were examined in human HNSCC cell lines from the University of Michigan Squamous Cell Carcinoma (UMSCC) series. The effect of SNX-5422 administered by oral gavage on tumor growth was examined in the UMSCC-11A murine xenograft model. Protein expression of Hsp90 client signal molecules were measured in tumor specimens harvested at three time points by immunohistochemistry (IHC) during SNX-5422 treatment, to identify the molecules mediating drug effects on proliferation, apoptosis and angiogenesis.

Results: SNX-2112 exhibited potent growth inhibition in the UMSCC cell lines, with an IC50 range of 25 - 75 nmol/L, and inhibited pro-survival signal kinase phospho-Akt at 24, 48, and 72 hours following exposure to SNX-2112 in UMSCC-11A. We also observed increased expression of pro-apoptotic transcription factor p53, and target gene PUMA, at 24, 48, and 72 hours following SNX-2112 exposure. Pro-drug SNX-5422 (PF-04929113) administered 20 mg/kg 5 days/wk or 50 mg/kg 3 days/wk for 3 wks significantly decreased tumor growth. By IHC, tumor specimens showed increased staining for p53 and apoptosis (TUNEL), and decreased staining for signal molecules Src, p-STAT3, and p-Akt together with markers of proliferation (Ki67) and vessel density (CD31). No apparent toxicity was observed in mice with SNX-5422 administered 20 mg/kg 5 days/wk for three weeks.

Conclusion: Synthetic Hsp90 inhibitor SNX-2112 is effective at degrading Hsp90 clients that play a significant role in proliferation, cell survival, and angiogenesis in HNSCC in vitro. In addition, SNX-5422 inhibits tumor growth by promoting apoptosis through modulation of several key signaling pathways. SNX-5422 warrants investigation as a clinical agent for treatment of head and neck cancer.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B80.
Abstract B94: The roles of ERK1/2 and ERK5 in age-related breast cancer proliferation
Authors: Monlish Darlene A. , Cavanaugh Jane E.
Published: June 2012

The purpose of the current study is to examine the relative roles of the extracellular signal-regulated kinases 1, 2, and 5 (ERK1/2 and ERK5) and novel benzimidazole inhibitor compounds in cellular proliferation in breast tumors with aging. Breast cancer risk progressively increases with age, in part due to an accumulation of genetic mutations that occur during cellular division and/or exposure to environmental toxins. It has been estimated that over the next thirty years the number of Americans older than 65 years of age will double. With this increase in the aged population, the incidence of breast cancer will rise; therefore, it is important to examine the underlying mechanisms involved in breast tumor proliferation with aging. It has been well established that activation of the mitogen-activated protein kinase (MAPK) ERK1/2 leads to increased cellular proliferation and differentiation in cancer cells. Many of these studies rely on pharmacological inhibitors that were thought to be specific for the ERK1/2 pathways. Interestingly, recent studies demonstrate that these inhibitors also block the activation of a novel MAPK, ERK5. Indeed, an increase in ERK5 activity has been observed in mammary tumors in aged patients. However, the roles of ERK1/2 and ERK5 in breast cancer cell proliferation with aging have not been fully explored. In our studies, the transgenic MMTV-neu mouse model was utilized to examine ERK1/2 and ERK5 activity with age. MMTV-neu mice develop spontaneous mammary tumors which make them an appropriate model for the studies of human breast cancer. Tumors were extracted from young (3 mo), middle (9 mo), and old (15 mo) mice. Higher levels of ERK5 expression and activity were observed in middle- and old-aged animals as compared to their younger counterpart. Similarly, ERK1/2 expression and activation were increased with age. To further study the role of the ERK pathways on cell proliferation with aging, the BT-474 human breast cancer cell line and the MMTV-neu cell line (MMC) were utilized. Cell lysates were collected at passages 2, 12, 24 and 36 to mimic aging. At early passages ERK5 was constitutively active under basal conditions. At later passages, an age-dependent increase in ERK5 was observed. Breast cancer cell proliferation may be regulated by ERK5 exclusively or in conjunction with ERK1/2. We next investigated how novel benzimidazole compounds can act as specific inhibitors of ERK5 signaling in MMC and BT-474 cells. Overall, these studies will provide novel information about the cellular mechanisms involved in cancer cell proliferation and progression with aging. A better understanding of the ERK1/2 and ERK5 pathways in age-related mammary cell proliferation may lead to the development of preventative therapeutics or treatment possessing enhanced specificity for aging patients.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B94.
Abstract B95: Targeting cancer cell metabolism: The combination of metformin and 2-deoxyglucose induces p53 dependent apoptosis in prostate cancer cells
Authors: Sahrab Issam Ben , Laurent Kathiane , Le marchand Brustel Yannick , Peraldi Sophie Giorgetti , Cormont Mireille , Auberger Patrick , Tanti Jean-François , Bost Frédéric
Published: June 2012

Targeting cancer cell metabolism is a new promising strategy to fight cancer. Metformin, a widely used antidiabetic agent exerts anti tumoral and antiproliferative action (1). In this study, we showed that the addition of metformin to 2 deoxyglucose (2DG) inhibited mitochondrial respiration and glycolysis in prostate cancer cells leading to a severe depletion in ATP. The association of the two drugs was much more harmful for cancer cells than the treatment with metformin or 2DG alone, leading to up to 95% inhibition of cell viability in LNCaP prostate cancer cells and 65% decrease of tumor growth in a xenograft model. Similarly, combination of the drugs was very powerful to inhibit PC3 and DU145 (prostate cancer), breast and colon cancer cells viability, on contrary, a moderate effect was observed in normal prostate epithelial cells. At the cellular level, metformin arrested cell cycle in G0/G1 and 2DG induced autophagy. The addition of metformin to 2DG inhibited 2DG mediated autophagy, blocked cell cycle in G2/M and more importantly induced caspase 3 activity in LNCaP cells (p53 wild-type). The tumor suppressor p53 plays a major role in apoptosis and cell metabolism, we showed that metformin combined to 2DG arrested prostate cancer cells in G2/M independently of the p53 status of the cells. Importantly, metformin/2DG did not induce apoptosis in PC3 (p53 null) and DU145 (p53 mutated) cells. Expression of a functional p53 in these cells restored caspase 3 activity showing that metformin/2DG induced apoptosis is p53 dependent. Thus, our study reinforces the growing interest of metabolic perturbators in cancer therapy and emphasizes the potential use of the combination of metformin and 2DG.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B95.
Abstract C105: Preclinical evaluation of galectin-1 targeting antiangiogenic, antitumor peptidomimetics
Authors: Dings Ruud P.M , Miller Michelle C. , Loren Melissa L. , Mayo Kevin H.
Published: June 2012

We have showed previously that the peptide 33mer anginex targets galectin-1 (gal-1) thereby inhibiting tumor endothelial cell proliferation via anoikis and attenuating tumor angiogenesis and tumor growth. Gal-1 binds β-galactoside groups on various cell surface receptors and is highly upregulated in tumor-activated endothelial cells. Differential stromal elevation of gal-1 over the tumor parenchyma has been reported in several cancers, including cancer of the breast, colon, prostate and ovaries. The aim of the present study was to develop gal-1 targeting anti-angiogenic peptidomimetics and anti-tumor clinical candidates for use in the management of human cancers. Based on structure-activity relationships of anginex, a partial-peptide mimetic was designed, using dibenzofuran (DBF) as a β-turn mimetic to maintain the two key β-strands and the bioactive amphipathic β-sheet conformation of the peptide. The best DBF-based compound 6DBF7 (13mer) inhibited tumor angiogenesis and tumor growth in vivo better than parent anginex. Subsequently, by substituting natural and non-natural amino acids, new DBF-based analogues were generated and tested in vitro. The analogs with improved anti-angiogenic activity and pharmacokinetic profile were then tested in tumor mouse models in vivo. The pre-clinical development of these novel anti-angiogenic and anti-cancer peptidomimetics will aid in the development of small-molecule mimetics and subsequently hold great promise for the management of human cancers in the clinic.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C105.
Abstract C107: The antitumor activity of SCV-07 is attributable, in part, to an inhibitory effect on STAT3 driven responses
Authors: Tuthill Cynthia W. , Subbarao Krishna Prasad , Ramachandra Raghuveer , Nagabhushanam Vijaya , Ramachandran Murali , Reddy Jhansi
Published: June 2012

Introduction: In recent years, agents that boost the immune system to break through tumor-induced immunosuppression have gained importance. The dipeptide, SCV-07 (gamma-D-glutamyl-tryptophan) has been shown to be efficacious in reducing progression of renal and lung carcinoma as well as melanoma in mouse models. SCV-07 also induces the elaboration of Th1 cytokines. Because the dipeptide has an effect on a diverse range of tumors, it is possible that SCV-07 has a global, antigen-independent effect on the immune system. Because STAT3 is known to be upregulated in tumor microenvironments, and the effect of STAT3 driven gene expression is global immune suppression of anti-tumor responses, we conducted the following studies to determine whether SCV-07 modulates STAT3-induced responses as part of its mechanism in stimulation of an anti-tumor immune response.

Experimental design: In vitro studies were conducted using B16F0 melanoma cells, transiently transfected with a STAT3 responsive element driving luciferase expression. Cells were incubated with varying concentrations of SCV-07, and luciferase expression was measured after 24 hours of incubation. In in vivo studies Balb/c mice were injected with B16 melanoma cells and the mice were either left untreated or were treated with SCV-07 at 5 mg/kg. Tumors were harvested on day 11 and were analyzed by flow cytometry for the presence of P-STAT3-positive cells.

Results: SCV-07 inhibited expression of STAT3 driven luciferase expression to the extent of ∼70 – 80%, depending on concentration of SCV-07. Further studies showed that SCV-07 additionally inhibited the translocation of STAT3 into the nucleus of HeLa cells. SCV-07 increased survival and inhibited the progression of melanoma growth in the B16 mouse model, and this inhibition was accompanied by reduced phosphorylated STAT3 staining at the tumor site as well as an influx of natural killer cells.

Conclusions: These results provide support that SCV-07 acts in an antigen independent manner to reduce STAT3 driven gene expression and potentiate anti-tumor immune responses.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C107.