The small molecule NSC676914A is cytotoxic and differentially affects NFκB signaling in ovarian cancer cells and HEK293 cells

Background

The small molecule NSC676914A was previously identified as an NF-κB inhibitor in TPA-stimulated HEK293 cells (Mol Can Ther 8:571-581, 2009). We hypothesized that this effect would also be seen in ovarian cancer cells, and serve as its mechanism of cytotoxicity. OVCAR3 and HEK293 cell lines stably containing a NF-κB luciferase reporter gene were generated.

Methods

Levels of NF-κB activity were assessed by luciferase reporter assays, after stimulation with LPA, LPS, TPA, and TNFα, in the presence or absence of a known NF-κB inhibitor or NSC676914A, and cytotoxicity was measured.

Results

NSC676914A was toxic to both OVCAR3 and HEK293 cells. We also investigated the cytotoxicity of NSC676914A on a panel of lymphoma cell lines with well characterized mutations previously shown to determine sensitivity or resistance to NF-κB inhibition. The compound did not show predicted patterns of effects on NF-κB activity in either lymphoma, ovarian or HEK293 cell lines. In HEK293 cells, the small molecule inhibited NF-κB when cells were stimulated, while in OVCAR3 cells it only partially inhibited NF-κB. Interestingly, we observed rescue of cell death with ROS inhibition.

Conclusions

The current study suggests that the effect of NSC676914A on NF-κB depends on cell type and the manner in which the pathway is stimulated. Furthermore, as it is similarly toxic to lymphoma, OVCAR3 and HEK293 cells, NSC676914A shows promising NF-κB-independent anti-cancer activity in ovarian tumor cells.

Phase I/Ib study of olaparib and carboplatin in BRCA1 or BRCA2 mutation-associated breast or ovarian cancer with biomarker analyses

BACKGROUND

Olaparib has single-agent activity against breast/ovarian cancer (BrCa/OvCa) in germline BRCA1 or BRCA2 mutation carriers (gBRCAm). We hypothesized addition of olaparib to carboplatin can be administered safely and yield preliminary clinical activity.

METHODS

Eligible patients had measurable or evaluable disease, gBRCAm, and good end-organ function. A 3 + 3 dose escalation tested daily oral capsule olaparib (100 or 200mg every 12 hours; dose level1 or 2) with carboplatin area under the curve (AUC) on day 8 (AUC3 day 8), then every 21 days. For dose levels 3 to 6, patients were given olaparib days 1 to 7 at 200 and 400 mg every 12 hours, with carboplatin AUC3 to 5 on day 1 or 2 every 21 days; a maximum of eight combination cycles were permitted, after which daily maintenance of olaparib 400mg every12 hours continued until progression. Dose-limiting toxicity was defined in the first two cycles. Peripheral blood mononuclear cells were collected for polymorphism analysis and polyADP-ribose incorporation. Paired tumor biopsies (before/after cycle 1) were obtained for biomarker proteomics and apoptosis endpoints.

RESULTS

Forty-five women (37 OvCa/8 BrCa) were treated. Dose-limiting toxicity was not reached on the intermittent schedule. Expansion proceeded with olaparib 400mg every 12 hours on days 1 to 7/carboplatin AUC5. Grade 3/4 adverse events included neutropenia (42.2%), thrombocytopenia (20.0%), and anemia (15.6%). Responses included 1 complete response (1 BrCa; 23 months) and 21 partial responses (50.0%; 15 OvCa; 6 BrCa; median = 16 [4 to >45] in OvCa and 10 [6 to >40] months in BrCa). Proteomic analysis suggests high pretreatment pS209-eIF4E and FOXO3a correlated with duration of response (two-sided P < .001; Pearson's R (2) = 0.94).

CONCLUSIONS

Olaparib capsules 400mg every 12 hours on days 1 to 7/carboplatin AUC5 is safe and has activity in gBRCAm BrCa/OvCa patients. Exploratory translational studies indicate pretreatment tissue FOXO3a expression may be predictive for response to therapy, requiring prospective validation.

Pathway-specific engineered mouse allograft models functionally recapitulate human serous epithelial ovarian cancer

The high mortality rate from ovarian cancers can be attributed to late-stage diagnosis and lack of effective treatment. Despite enormous effort to develop better targeted therapies, platinum-based chemotherapy still remains the standard of care for ovarian cancer patients, and resistance occurs at a high rate. One of the rate limiting factors for translation of new drug discoveries into clinical treatments has been the lack of suitable preclinical cancer models with high predictive value. We previously generated genetically engineered mouse (GEM) models based on perturbation of Tp53 and Rb with or without Brca1 or Brca2 that develop serous epithelial ovarian cancer (SEOC) closely resembling the human disease on histologic and molecular levels. Here, we describe an adaptation of these GEM models to orthotopic allografts that uniformly develop tumors with short latency and are ideally suited for routine preclinical studies. Ovarian tumors deficient in Brca1 respond to treatment with cisplatin and olaparib, a PARP inhibitor, whereas Brca1-wild type tumors are non-responsive to treatment, recapitulating the relative sensitivities observed in patients. These mouse models provide the opportunity for evaluation of effective therapeutics, including prediction of differential responses in Brca1-wild type and Brca1-deficient tumors and development of relevant biomarkers.

Deleterious BRCA1/2 mutation is an independent risk factor for carboplatin hypersensitivity reactions

Background:

We tested the hypothesis that BRCA1/2 mutation carriers with ovarian cancer are at higher risk of carboplatin hypersensitivity reactions (HSRs).

Methods:

Medical records of women enrolled in two carboplatin+olaparib clinical trials (NCT01237067/NCT01445418) were reviewed. A maximum of eight cycles containing carboplatin were administered.

Results:

All women (N=87) had good performance status and end-organ function. Incidences of carboplatin HSR before enrolment and on study were 17% and 21%, respectively. Most patients who developed carboplatin HSR had a deleterious BRCA1/2 mutation (93%) vs 50% in patients without HSR (P<0.0001). Multivariable analysis accounting for potential confounding variables including age, history of allergies, and cumulative prior carboplatin cycles confirmed deleterious BRCA1/2 mutation as an independent risk factor for carboplatin HSR (odds ratio 13.1 (95% confidence interval 2.6–65.4), P=0.0017). Mutation carriers had onset of carboplatin HSR at lower cumulative exposure (P=0.003). No significant difference in outcome was observed on our study between patients with and without a history of HSR.

Conclusion:

Deleterious BRCA1/2 mutation increased susceptibility and shortened time to carboplatin HSR, independently of other reported factors. These data suggest that at-risk women should be counselled regarding likelihood, symptoms, and potential earlier onset of carboplatin HSRs.

Phase I/Ib study of the PARP inhibitor olaparib (O) with carboplatin (C) in BRCA1/2 mutation carriers with breast or ovarian cancer (Br/OvCa) (NCT00647062)

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Background: O capsules have single agent activity against Br/OvCa in BRCA1/2mut+carriers. Our goals were to define safety and explore predictive biomarkers for an OC regimen in these pts. Methods: 3x3 dose escalation optimized daily oral O (100 or 200mg q12h; DL1&2) with IV C/AUC3 on d8 and q21d, and on DL3-6, O d1-7 at 200 then 400mg q12h with C/AUC3-5 on d2. ≤ 8 OC cycles were given, followed by daily O until progression. Safety was assessed q cycle and response q2 cycles. PBMCs were collected for polymorphism analysis (PARP1; XRCC1), and serially for PAR incorporation by ELISA. Paired tumor biopsies (pre/postC1) were collected in phase Ib pts for protein microarray (RPPA) and TUNEL endpoints. Results: 45 women (37Ov/8Br) with BRCA1 (32), BRCA2 (11), 1 each BRCA1&2 and BRCApro 68% received OC. All OvCa pts previously received C (6-55mo prior, median 14). DLT was thrombocytopenia (O 200mg q12h, C/AUC3 2/5 pts). MTD was not reached on the intermittent schedule. RP2D is O 400mg q12hx14, C/AUC5 (1/6: g4 thrombocytopenia). Gr 3/4 AEs included neutropenia (42%), thrombocytopenia (20%), anemia (13%), C hypersensitivity (9%), and fatigue (7%). 7 pts discontinued C early for hypersensitivity reaction (4) or myelosuppression (3). Responses included 1 CR (BrCa, 17mo), PR in 15/34 OvCa (44%; 3-28+mo) and 6/8 BrCa (5-24+ mo), and stabilization in 14/34 OvCa (41%; 3-25+ mo) and a BrCa pt (11mo) for a clinical benefit rate of 85% OvCa, 100% BrCa. RPPA (N=10) showed high FOXO3 and NFκB1 preC1 correlated with time on study (r=0.822, p=0.0035; r=-0.832, p=0.0028, respectively). The change post-preC1 correlated with time on study for the combination of eIF4E/G, caspase 7, pPI3K, FOXO3a, p62, E-cadherin, PCNA, Bim, and Bcl2 (r=-0.855, p=0.0068). Post-preC1 TUNEL results trended to correlate with response (p=0.07). PBMC PAR concentrations and PARP1/XRCC1 polymorphisms did not correlate with response. Conclusions: O 400mg q12h x14 with C/AUC5 q21d is active and tolerable in Br/OvCa BRCAmut+ pts despite interactive marrow suppression. Exploratory translational studies indicate FOXO3 and NFkB1 may be predictive for response to therapy, requiring a prospective validation. Clinical trial information: NCT00647062.

SARC006: Phase II trial of chemotherapy in sporadic and neurofibromatosis type 1 (NF1)-associated high-grade malignant peripheral nerve sheath tumors (MPNSTs)

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Background: MPNSTs occur in 10% of the NF1 population, and retrospective, pooled analyses have reported worse chemotherapy response for NF1 (9-18%) compared to sporadic MPNSTs (39-55%). Methods: We prospectively evaluated the objective response (OR) rate, [complete responses (CR) and partial responses (PR) WHO criteria] of children and adults with high-grade, unresectable or metastatic chemotherapy naive NF1 associated versus sporadic MPNST after 2 cycles of ifosfamide and doxorubicin (IA) followed by 2 cycles of ifosfamide and etoposide (IE) as primary endpoint. This was followed by surgery and/or radiation for local control and up to 2 more cycles of IA and IE each. Pathology was centrally confirmed. A Simon optimal two-stage design was used with a target response rate of 40% and 17 patients per stratum in the first stage. With 4+/17 ORs, enrollment was to be expanded to 37 patients per stratum, and 11+/37 ORs would be potentially consistent with a 40% OR rate. Results: Both initial stages met criteria for enrollment expansion with 4/17 PRs in NF1 and 4/12 PRs in sporadic MPNSTs, but only 1 additional PR was observed in the expanded NF1 stratum. Of the 9 PRs, 5 were first observed after 2 cycles IA, and additional 4 after 2 cycles IE. Enrollment was slower than expected and the trial was closed before full accrual. Conclusions: While the primary trial objective was not reached due to slow enrollment, with only 5/29 ORs in the NF1 stratum the desired OR rate of 11+/37 would have unlikely been met even if accrual had been completed. We observed a lower OR rate in NF1 compared to sporadic MPNSTs similar to retrospective literature reports. However, our trial was not powered to detect a difference in response rates between the two strata. In addition to PRs after both IA and IE, disease stabilization was achieved in most patients. Novel strategies including the evaluation of targeted agents in combination with chemotherapy should be considered. Clinical trial information: NCT00304083. [Table: see text]

Abstract 2007: The NF-kB pathway is constitutively active in endometrial cancer

The NF-κB Pathway is Constitutively Active in Endometrial Cancer

Metastatic endometrial cancer (EC) is a disease for which therapeutic options are limited and prognosis is poor. Although 75% of endometrial cancers are diagnosed at an early stage and cured by surgery, 15-20% develop metastases and die from their disease. Uterine papillary serous carcinoma (UPSC) occurs in less than 10% of patients, but has a worse clinical outcome. Prior studies suggest that NF-kB signaling may play a role in UPSC. We therefore proceeded with a detailed investigation of the NF-κB pathway in EC.

Methods: A set of 11 endometrial cancer cell lines, representing endometrioid EC and UPSC, were tested for sensitivity to a specific inhibitor of IKKβ after 3 days of drug treatment using XTT assay. Western blot was used to assess changes in NF-κB proteins after treatment of sensitive UPSC cell lines ARK-1 and ACI-126 with IKKβ inhibitor over a time series ranging from 15 min to 24h. RNA was extracted from ARK-1 and ACI-126 cell lines after 48h treatment with IKK-2 inhibitor IV or DMSO control, and after transfection of the same cell lines with IκBα super-repressor or empty vector control. RNA was hybridized to Affymetrix U133 Plus2.0 microarray platform for gene expression profiling and the data was analyzed using mAdb. Gene and protein expression was examined in patient samples to verify biologic relevance.

Results: Six of 11 cell lines were sensitive to IKKβ inhibitor with IC50s ranging between 4 and 10uM. The highest sensitivity occurred in two UPSC cell lines ARK-1 and ACI-126. Following pharmacologic IKKβ inhibition, nuclear levels of NF-κB p65 decreased by 3h and began to increase again from 6h to 24h. Cytoplasmic NF-κB p65 increased from 15 min to 3h and then began to fall. Gene expression profiling after IKKβ inhibition, either by drug treatment or by mutant IkBa super-repressor, revealed an overlapping gene signature in the two UPSC cell lines. The genes were co-expressed across the gene expression profiles of patients with EC, and were significantly highest in African American women with UPSC.

Conclusions: There is aberrant signaling through the NF-κB pathway in a subset of EC. An IKKβ target gene signature shows that this pathway is most relevant in African American women with UPSC. Therefore, targeting NF-kB may provide a novel treatment strategy for this underserved population with a rare variant of EC.

Citation Format: Anne M. Noonan, Yovanni Casablanca, George L. Maxwell, Christina M. Annunziata. The NF-kB pathway is constitutively active in endometrial cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2007. doi:10.1158/1538-7445.AM2013-2007

A phase II clinical trial of polyethylene glycol-conjugated L-asparaginase in patients with advanced ovarian cancer: Early closure for safety

The anti-angiogenic activity of L-asparaginase (L-ASP) and the sensitivity of ovarian cancer cell lines to L-ASP has been previously demonstrated by preclinical findings. The aim of this clinical trial was to translate those findings and evaluate the activity of polyethylene glycol-conjugated L-asparaginase (PEG-ASP or pegaspargase) in advanced ovarian cancer. Women with recurrent ovarian cancer and good end-organ function were enrolled in an open-label phase II trial of PEG-ASP at a dose of 2,000 IU/m² by intravenous infusion every 2 weeks. Patients were evaluated for response every 8 weeks and for toxicity on an ongoing basis. Early stopping rules for toxicity and activity were included. Four patients were enrolled and received a total of 7 treatment cycles. The study ended accrual by invoking an early stopping rule, after excessive toxicity was identified in patients. Drug-related toxicities included grade 2 pancreatitis, fatigue, neutropenia, hypoalbuminemia, weight loss, dehydration, decreased fibrinogen and 1 case of grade 3 hypersensitivity reaction during cycle 2. One patient died during the study. No patients were evaluable for response. PEG-ASP was poorly tolerated in this group of advanced-stage ovarian cancer patients and no conclusions regarding activity may be drawn. Further studies of PEG-ASP in ovarian cancer patients are not recommended.

Translational predictive biomarker analysis of the phase 1b sorafenib and bevacizumab study expansion cohort

Predictive biomarkers are needed to triage patients to the best therapy. We prospectively planned examination of sequential blood, biopsy, and functional imaging with which to confirm the mechanism and to identify potential predictive biomarkers in a phase Ib clinical trial expansion of patients with solid tumors receiving sorafenib/bevacizumab. The maximally tolerated doses of sorafenib at 200 mg twice daily with bevacizumab at 5 mg/kg every other week were given to biopsiable patients. Patients were randomized to receive either sorafenib or bevacizumab monotherapy for the first 28-day cycle with the second drug added with cycle 2. Biopsies, dynamic contrast-enhanced MRI, and fluorodeoxyglucose-proton emission tomography were done pre-therapy and at 2 and 6 weeks (2 weeks into combination therapy). Tumor and serum proteomics, Ras/Raf mutational analysis, and functional imaging results were examined individually and across the dataset to identify potential changes predictive of response to therapy and those that confirm the biochemical drug mechanism(s). Therapy with sorafenib/bevacizumab resulted in clinical benefit in 45% of this mixed solid tumor group. ERK activation and microvessel density were decreased with monotherapy treatment with sorafenib or bevacizumab, respectively; whereas a decreased signal over the group of total AKT, phospho(p)-VEGF receptor2, p-endothelial nitric-oxide synthase, b-RAF, and cleaved poly(ADP-ribose) polymerase was associated with earlier progression of disease. Tumor metabolic activity decreased in those patients with clinical benefits lasting longer than 4 months, and activity increased with progression of disease. Cleavage of caspase 3 and poly(ADP-ribose) polymerase was increased, and Ki67 expression decreased in patients with prolonged clinical benefits, consistent with decreased proliferation and increased apoptosis. The conglomerate analysis, incorporating pharmacodynamic and tumor biochemistry, demonstrated sorafenib/bevacizumab-targeted vascular activity in the tumor. Results suggest potential biomarkers for which changes, as a group, during early therapeutic exposure may predict clinical benefit.

IKK-ε coordinates invasion and metastasis of ovarian cancer

Inhibitor of IκB kinases (IKK) are key regulators of NF-κB signaling. Three IKK isoforms-α, β, and ε-have been linked to oncogenesis, yet the precise components of NF-κB signaling in ovarian cancer have not yet been dissected. We surveyed 120 ovarian cancer specimens for IKK-ε expression. Notably, cytoplasmic expression was elevated in metastatic lesions relative to primary tumors (P = 0.03). Therefore, we hypothesized that IKK-ε drives ovarian cancer metastasis. IKK-ε was identified previously as a breast cancer oncogene and was associated with poor clinical outcome in ovarian cancer. We now define an ovarian cancer-specific IKK-ε-regulated gene expression signature using stably expressed short hairpin RNA targeting IKK-ε. Pathway analysis of the signature indicated that IKK-ε regulates expression of genes involved in cell motility and inflammation. We further showed that IKK-ε depletion in metastatic ovarian cancer cell lines decreased growth, adhesion, and invasion. Consistently, human xenografts depleted of IKK-ε in mice showed decreased aggressiveness, whereas overexpression of IKK-ε in a less invasive ovarian cancer cell line increased metastasis in vivo. Taken together, these data provide evidence that IKK-ε is a key coordinator of invasion and metastasis programs in ovarian cancer. Inhibition of IKK-ε signaling thus emerges as a viable therapeutic strategy in women whose ovarian cancer shows aberrant activation of this pathway.

Feasibility and safety of sequential research-related tumor core biopsies in clinical trials with anti-angiogenic and targeted therapies

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Background: There has been increasing interest in serial/paired research biopsies (bx) in studies of molecularly targeted therapies. Definition of optimal target tissue and patient characteristics for safe and feasible research tumor bx in the era of anti-angiogenic and targeted therapies is needed. Methods: IRB-approved review of retrospective clinical data including patient demographics, pre-and post-procedure and recovery notes, and radiographic bx images. The cohort consisted of 142 pts scheduled for serial bx enrolled in phase 1 (5) and phase 2 (1) studies. Tumor core bx were obtained percutaneously under local anesthesia using a 16 or 18g needles under US or CT visualization by interventional radiologists. Results: Paired tumor core bx were collected in 96 pts (68%) and baseline only in 42 pts (32%). Bx were aborted in 4 pts due to cystic mass (3) and safety (1). 132 pts were female and 10 pts were male, median age 56 yrs (27-78), median BMI 25.8 (14.4-46.2), ECOG PS 0-2, and normal end-organ function. All pts had recurrent metastatic cancers (gynecologic 121, breast 6, sarcoma 5, melanoma 4, colon 2, adrenal 1, mesothelioma 1, RCC 1, papillary thyroid ca 1). 67 pts (51%) were on bevacizumab (bev)-based therapy at the time of their 2nd/3rd bx (bev + sorafenib; bev + dasatinib); others received gefitinib (27), imatinib (23), vandetinib (9), or olaparib + carboplatin (16). Median tumor size was 2.7cm (1-14.5cm). Bx sites were abd/pelvic masses 42, liver 40, lymph nodes 42, abd/chest wall 12, lung 4 (3 pleural, 1 parenchymal), and psoas muscle 1. Minor complications were observed in four pts (3%; uncomplicated liver subcapsular hematoma [1]; vasovagal syncope responding to fluids [2]; uncomplicated pneumothorax without intervention [1]) and there were no major complications. The median number of tumor cores was 3 (1-6) at the baseline, 2nd (during or at the end of the first cycle) and 3rd time point (during cycle 2). Conclusions: Core needle bx of deep internal lesions such as intra-abdominal masses and retroperitoneal lymph nodes can be obtained percutaneously under imaging guidance. Sequential tumor bx are feasible and safe for pts on anti-angiogenic and chemotherapeutic agents.

Abstract 1754: A pharmacokinetics/pharmacodynamics study of sequence specificity of the PARP inhibitor, olaparib (O) with carboplatin (C) in recurrent women's cancers NCT01237067

Background: C, O, and C+O have documented activity in BRCA1/2mut+ or BRCA-like breast and ovarian cancers (Br/OvCa). The effect of drug sequence on DNA damage and cell death is unknown. Our in vitro modeling suggests that exposure to O prior to C (O&gt;C) reduced double stranded DNA damage and cell loss. Our trial tests the hypothesis that C&gt;O causes more cellular injury. Methods: Eligible pts have recurrent women's cancers, good end organ function, and evaluable disease. A 3+3 dose escalation run-in defined the O tablet dose in combination with C (AUC 4). The study will now randomize pts to schedule A or B (below), allowing intra-pt and inter-cohort analysis of PK/PD endpoints. PBMCs will be collected C1/2 for measurement of platination and DNA damage/repair; DNA repair protein integrity will be assessed on archival tissues. Clinical benefit, response frequency and duration, and toxicity will be ascertained. Mutation carriers will undergo progression biopsy for analysis of BRCA1/2 re-expression mutations. Results: The phase I portion is complete. 12 women (8Ov/3Br/1Endometrial[En]) have been accrued on 3 dose levels (DLs). Median prior number of regimens was 5. No DLT have been seen in 5 evaluable pts on DL3 (O tablet 200mg q12h/C AUC4 [1 pt pending]). Gr3 AEs included neutropenia (44%), and gr2 were anemia (56%), fatigue (22 %), C hypersensitivity (22%), thrombocytopenia (11%), and nausea (11%). 1 pt (DL2; stable disease) died of unrelated bleeding during C4. Clinical benefit has been observed in 8 evaluable pts with PR in 2 BRCA1mut+ OvCa (9+, 11+ mo), stabilization &gt; 4mo in 6 pts (4OvCa,1BrCa, 1EnCa), and 3 are TETE. Conclusions: O in tablet formulation at 200mg q12h x 7d with C AUC4 q21d is active and tolerable, with observed interactive marrow suppression. Subsequent women will be randomized to examine schedule dependence of activity and toxicity.

Phase 1, open-label study of MEDI-547 in patients with relapsed or refractory solid tumors

Background Targeting the cell-surface receptor EphA2, which is highly expressed in some solid tumors, is a novel approach for cancer therapy. We aimed to evaluate the safety profile, maximum tolerated dose (MTD), pharmacokinetics, and antitumor activity of MEDI-547, an antibody drug conjugate composed of the cytotoxic drug auristatin (toxin) linked to a human anti-EphA2 monoclonal antibody (1C1), in patients with solid tumors relapsed/refractory to standard therapy. Methods In this phase 1, open-label study with planned dose-escalation and dose-expansion cohorts, patients received a 1-h intravenous infusion of MEDI-547 (0.08 mg/kg) every 3 weeks. Results Six patients received 0.08 mg/kg; all discontinued treatment. Dose escalation was not pursued. The study was stopped before cohort 2 enrollment due to treatment-related bleeding and coagulation events (hemorrhage-related, n = 3; epistaxis, n = 2). Therefore, lower doses were not explored and an MTD could not be selected. The most frequently reported treatment-related adverse events (AEs) were increased liver enzymes, decreased hemoglobin, decreased appetite, and epistaxis. Three patients (50%) experienced treatment-related serious AEs, including conjunctival hemorrhage, pain (led to study drug discontinuation), liver disorder, and hemorrhage. Best response included progressive disease (n = 5; 83.3%) and stable disease (n = 1; 16.7%). Minimal or no dissociation of toxin from 1C1 conjugate occurred in the blood. Serum MEDI-547 concentrations decreased rapidly, ~70% by 3 days post-dose. No accumulation of MEDI-547 was observed at 0.08 mg/kg upon administration of a second dose 3 weeks following dose 1. Conclusions The safety profile of MEDI-547 does not support further clinical investigation in patients with advanced solid tumors.

Abstract 1479: IKK-epsilon contributes to the malignant progression of ovarian cancer

Background and significance: The mechanism through which the NF-κB pathway affects the initiation, propagation and dissemination of ovarian cancer is unknown. I-κB kinases (IKKs) are key regulators of NF-κB signaling. Three IKK isoforms – α, β and ∈ – have been linked to oncogenesis, yet the precise components of NF-κB signaling mechanisms in ovarian cancer have not yet been dissected. IKK∈ was identified as an oncogene in breast cancer and has been associated with poor clinical outcome in ovarian cancer. This IKK isoform can regulate the innate immune response via activation of interferon-response factors, or can signal through classical NF-κB mechanisms by inactivating CYLD, a negative regulator of the pathway. Therefore, the molecular context is key to determining which oncogenic pathway is activated and how the signals will ultimately affect the cancer cel We hypothesized that IKK∈ drives ovarian cancer growth and metastasis.

Methods: The expression of IKKe was determined in primary ovarian cancer specimens and human ovarian cancer cell lines. Ovarian cancer cell lines were depleted of IKKe using RNA interference and tested in functional assays, including anchorage-independent growth, basement membrane invasion, and heterotypic cell adhesion. Orthotopic xenograft mouse models were used to determine the role of IKKe in metastasis in vivo. Gene expression microarrays established an IKKe-specific signature in ovarian cancer.

Results: We surveyed 120 ovarian cancer specimens (42 primary carcinomas, 78 solid metastases) for IKK∈ expression. Notably, cytoplasmic expression was elevated in metastatic lesions relative to primary tumor sites (p=0.03). RNA interference targeting IKK∈ in a panel of 5 metastatic ovarian cancer cell lines inhibited cell growth and prevented colony formation in soft agar. An ovarian cancer-specific IKK∈-regulated gene expression signature was identified using stably expressed shRNA targeting IKK∈. Pathway analysis of the signature indicated that IKK∈ regulates the expression of genes essential to diverse processes known to contribute to the malignancy of ovarian cancer, including TGFb and HIF1a pathways. Orthotopic xenograft experiments in mice demonstrated decreased aggressiveness of IKK∈-depleted ovarian cancer cells.

Conclusion: These data provide evidence that IKK∈ plays a key role in ovarian cancer metastasis. Understanding IKK∈-regulated signaling in ovarian cancer will identify novel pathway interactions for context-specific therapeutics in the poor prognostic group of women whose ovarian cancers over-express IKK∈.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1479. doi:10.1158/1538-7445.AM2011-1479

Poly (ADP-ribose) polymerase as a novel therapeutic target in cancer

Cancer chemotherapy exploits limitations in repairing DNA damage in order to kill proliferating malignant cells. Recent evidence suggests that cancers within and across tissue types have specific defects in DNA repair pathways, and that these defects may predispose for sensitivity and resistance to various classes of cytotoxic agents. Poly (ADP-ribose) polymerase (PARP) and BRCA proteins are central to the repair of DNA strand breaks and, when defective, lead to the accumulation of mutations introduced by error-prone DNA repair. Breast, ovarian, and other cancers develop in the setting of BRCA deficiency, and these cancers may be more sensitive to cytotoxic agents that induce DNA strand breaks, as well as inhibitors of PARP activity. A series of recent clinical trials has tested whether PARP inhibitors can achieve synthetic lethality in BRCA-pathway-deficient tumors. Future studies must seek to identify sporadic cancers that harbor genomic instability, rendering susceptibility to agents that induce additional and lethal DNA damage.

Nuclear factor kappaB transcription factors are coexpressed and convey a poor outcome in ovarian cancer

BACKGROUND

Recent work has suggested a role for nuclear factor kappaB (NF-kappaB) in the propagation of ovarian cancer cell lines, but the significance and mechanism of NF-kappaB in ovarian cancer is unknown. The authors hypothesized that the NF-kappaB pathway is over activated in aggressive ovarian cancers.

METHODS

The levels of 3 NF-kappaB transcription factors, the activating inhibitors of NF-kappaB (IkappaB) kinases, and the NF-kappaB target matrix metalloproteinase 9 (MMP9) were assessed by immunohistochemistry in specimens of ovarian cancer that were obtained at diagnosis from a cohort of 33 patients who subsequently received combined paclitaxel, cisplatin, and cyclophosphamide. Associations were made between NF-kappaB pathway proteins and outcome. The validation of coexpression was performed at the gene level in 2 independently collected cohorts of 185 and 153 ovarian cancers.

RESULTS

The presence of NF-kappaB proteins in newly diagnosed advanced ovarian cancers was established, and a potential association with overall survival was identified. Transcription factors p65 and v-rel reticuloendotheliosis viral oncogene homolog B (RelB) were coexpressed with IkappaB kinase alpha, 1 component of a key trimolecular regulatory complex. Coexpression of the NF-kappaB machinery suggested activity of NF-kappaB signaling in these ovarian tumors. A significant association of p50 with poor overall survival was observed (P = .02). MMP9 expression had the opposite association, in which patients who had tumors without MMP9 staining had the poorest prognosis (P = .01), and this association held true at the gene expression level in an independently collected cohort of 185 ovarian cancers.

CONCLUSIONS

The deregulation of NF-kappaB activity may influence outcome in women who receive standard therapy for advanced ovarian cancer. Modification of the NF-kappaB pathway may present an opportunity to improve outcome in the subset of women who have pathway activity.

Activation of NF-kappaB signaling by inhibitor of NF-kappaB kinase beta increases aggressiveness of ovarian cancer

The NF-kappaB family of transcription factors has been implicated in the propagation of ovarian cancer, but the significance of constitutive NF-kappaB signaling in ovarian cancer is unknown. We hypothesized that constitutive NF-kappaB signaling defines a subset of ovarian cancer susceptible to therapeutic targeting of this pathway. We investigated the biological relevance of NF-kappaB in ovarian cancer using a small-molecule inhibitor of inhibitor of NF-kappaB kinase beta (IKKbeta) and confirmed with RNA interference toward IKKbeta. We developed a gene expression signature of IKKbeta signaling in ovarian cancer using both pharmacologic and genetic manipulation of IKKbeta. The expression of IKKbeta protein itself and the nine-gene ovarian cancer-specific IKKbeta signature were related to poor outcome in independently collected sets of primary ovarian cancers (P = 0.02). IKKbeta signaling in ovarian cancer regulated the transcription of genes involved in a wide range of cellular effects known to increase the aggressive nature of the cells. We functionally validated the effect of IKKbeta signaling on proliferation, invasion, and adhesion. Downregulating IKKbeta activity, either by a small-molecule kinase inhibitor or by short hairpin RNA depletion of IKKbeta, blocked all of these cellular functions, reflecting the negative regulation of the target genes identified. The diversity of functions controlled by IKKbeta in ovarian cancer suggests that therapeutic blockade of this pathway could be efficacious if specific IKKbeta inhibitor therapy is focused to patients whose tumors express a molecular profile suggestive of dependence on IKKbeta activity.

Abstract 1978: The poly-SUMO protein specific E3 ubiquitin ligase RNF4 is induced in multiple myeloma and reduces bortezomib-induced cell killing

Multiple Myeloma (MM) is a fatal neoplasm of B-cell origin characterized by the clonal proliferation and accumulation of malignant plasma cells in the bone marrow. While recent advances in mechanistic understanding and treatment modalities have extended median survival to &gt;6 years and 10% of patients survive &gt;10 years, the vast majority of MM remains incurable with conventional, high dose therapy or stem cell transplantation. Bortezomib is a selective, reversible inhibitor of the 26S proteasome that inhibits protein degradation and is now FDA-approved for the treatment of newly diagnosed, relapsed and refractory MM. Though the catabolism of ubiquitinated substrates has been targeted therapeutically with significantly improved prognosis, patient response to bortezomib remains highly variable and cannot be predicted accurately. E3 ligases confer specificity on target selection for Ub+proteasome degradation. We therefore analyzed the expression of individual E3's using a microarray dataset obtained from MM patient tumor samples and found a striking variability in the expression level of individual E3 ligases between normal plasma cells and patients MM cells. RNF4, an E3 specific for poly-sumoylated proteins, was induced in MM patients and correlated with decreased patient response to the proteasome inhibitor bortezomib. Expression profiling of pretreatment tumor samples obtained from MM patients in independent clinical trials were used to generate a signature that correlated expression of SUMO+Ub+Proteasome pathway components with clinical outcome to predict patient response to bortezomib. Experimental validation by overexpression of RNF4-wt rendered myeloma cell lines relatively resistant to bortezomib while RNF4 depletion by shRNA enhanced sensitivity to bortezomib. Transfection of HA-tagged SUMO followed by bortezomib exposure led to the accumulation of HA-SUMO∼conjugates that were immunoreactive with Ub and proteasome components to further link the pathways. In summary, RNF4 an E3 ligase specific for SUMO-conjugates and induced in myeloma, modulates the cellular response to proteasome-based therapy and promotes bortezomib resistance. Our results support regulators of the sumoylation pathway as biomarkers to predict clinical response to bortezomib and provide evidence for targeting SUMO pathway to improve therapeutic outcome in myeloma in general and bortezomib specifically.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1978.

PARP inhibitors in BRCA1/BRCA2 germline mutation carriers with ovarian and breast cancer

BRCA and poly-ADP ribose polymerase (PARP) regulate pathways of DNA repair. Due to the accumulation of mutations introduced by error-prone DNA repair, breast and ovarian cancers develop in the setting of BRCA deficiency. A series of recent clinical trials has tested the use of PARP inhibition as a therapeutic strategy to target BRCA-deficient tumors.

Vandetanib, designed to inhibit VEGFR2 and EGFR signaling, had no clinical activity as monotherapy for recurrent ovarian cancer and no detectable modulation of VEGFR2

PURPOSE

To evaluate clinical activity and target modulation of vandetanib in women with recurrent ovarian cancer.

EXPERIMENTAL DESIGN

A phase II trial of orally administered vandetanib 300 mg daily was designed to include analyses of target inhibition through paired biopsies and dynamic imaging. Core 18-gauge needle biopsies and dynamic contrast-enhanced magnetic resonance imaging were obtained before initiation of therapy and 6 weeks into therapy. Biopsy samples were subjected to reverse-phase protein lysate array endpoint analysis. Cytokine concentrations were measured by enzyme-linked immunosorbent assay in serially collected plasma samples.

RESULTS

Twelve patients entered the study, and accrual was terminated in the first stage because of lack of response or disease stabilization beyond 6 months. Adverse events included rash, diarrhea, and prolonged QT interval corrected for heart rate, but not hypertension. Exploratory analyses showed that epidermal growth factor receptor (EGFR) phosphorylation was reduced in the eight paired biopsy sets obtained; vascular endothelial growth factor (VEGF) receptor-2 phosphorylation was not consistently affected nor were dynamic contrast-enhanced MRI permeability and flow parameters. Serial plasma VEGF concentrations were variable and did not significantly change in the 11 patients assessed.

CONCLUSIONS

Vandetanib 300 mg daily monotherapy had no significant clinical benefit in this disease setting. Proteomic analysis of paired biopsies detected both phosphorylated-EGFR and phosphorylated-VEGF receptor-2 in ovarian tumor tissue, but only phosphorylated-EGFR was measurably inhibited by vandetanib.

Abstract C158: IKKβ inhibition modulates NF-κB signaling and decreases aggressiveness of ovarian cancer

The NF-κB family of transcription factors has been implicated in the propagation of ovarian cancer, but the significance of constitutive NF-κB signaling in ovarian cancer is unknown. We hypothesized that constitutive NF-κB signaling defines a subset of ovarian cancer susceptible to therapeutic targeting of this pathway. To this end, we investigated the biological relevance of NF-κB in ovarian cancer cell lines using a small molecule inhibitor of IKKβ, and confirmed with RNA interference using stably expressed short hairpin RNA molecules towards IKKβ. We demonstrate here that the expression of IKKβ protein itself and the ovarian cancer-specific signature of IKKβ-regulated genes are related to poor outcome in independently collected sets of primary ovarian cancers. IKKβ signaling in ovarian cancer regulates the transcription of genes involved in a wide range of cellular effects known to increase the aggressive nature of the cells. We functionally validated the effect of IKKβ signaling on proliferation, invasion and adhesion in ovarian cancer cell lines. IKKβ was involved in all of these cellular functions, reflecting its modulation of the target genes identified. The diversity of functions controlled by IKKβ in ovarian cancer suggest that therapy targeted to this pathway could be efficacious if specific IKKβ inhibitor therapy is focused to patients whose tumors express a molecular profile suggestive of dependence on IKKβ activity.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C158.