Michael V. Seiden

CD133 Expression Defines a Tumor Initiating Cell Population in Primary Human Ovarian Cancer

Evidence is accumulating that solid tumors contain a rare phenotypically distinct population of cells, termed cancer stem cells (CSC), which give rise to and maintain the bulk of the tumor. These CSC are thought to be resistant to current chemotherapeutic strategies due to their intrinsic stem‐like properties and thus may provide the principal driving force behind recurrent tumor growth. Given the high frequency of recurrent metastasis associated with human ovarian cancer, we sought to determine whether primary human ovarian tumors contain populations of cells with enhanced tumor‐initiating capacity, a characteristic of CSC. Using an in vivo serial transplantation model, we show that primary uncultured human ovarian tumors can be reliably propagated in NOD/SCID mice, generating heterogeneous tumors that maintain the histological integrity of the parental tumor. The observed frequency of tumor engraftment suggests only certain subpopulations of ovarian tumor cells have the capacity to recapitulate tumor growth. Further profiling of human ovarian tumors for expression of candidate CSC surface markers indicated consistent expression of CD133. To determine whether CD133 expression could define a tumor‐initiating cell population in primary human ovarian tumors, fluorescence‐activated cell sorting (FACS) methods were employed. Injection of sorted CD133+ and CD133− cell populations into NOD/SCID mice established that tumor‐derived CD133+ cells have an increased tumorigenic capacity and are capable of recapitulating the original heterogeneous tumor. Our data indicate that CD133 expression defines a NOD/SCID tumor initiating subpopulation of cells in human ovarian cancer that may be an important target for new chemotherapeutic strategies aimed at eliminating ovarian cancer. STEM CELLS 2009;27:2875–2883

Risk stratification for desensitization of patients with carboplatin hypersensitivity: Clinical presentation and management

BACKGROUNDnWomen with ovarian cancer treated with chemotherapeutic platinum agents frequently develop hypersensitivity reactions (HSRs). How best to risk-stratify patients for desensitization is uncertain.nnnOBJECTIVESnTo evaluate skin test (ST) reactivity to carboplatin in patients with recent and remote histories of carboplatin HSR and to review the relationship between skin test reactivity and tolerance of subsequent carboplatin desensitization.nnnMETHODSnThirty-eight women with carboplatin HSR were evaluated by ST to carboplatin. Thirty women subsequently underwent 106 desensitizations to carboplatin.nnnRESULTSnCarboplatin ST was positive in 25 of 38 patients (66%). Of patients with recent HSR (<3 months), 20 of 24 (83%) tested positive, whereas 5 of 14 (36%) with remote HSR (>9 months) tested positive (P < .01). Nineteen carboplatin ST+ and 11 ST- patients underwent desensitization to carboplatin. Seven ST+ patients (37%) had mild HSR during desensitization but completed the desensitization with additional treatment or protocol modification. ST- patients with a recent history of HSR (n = 3) tolerated a rapid protocol without HSR and remained ST- with repeated testing. Six of 8 ST- patients (75%) with remote HSR reacted during desensitization. The HSRs were more severe and often associated with an elevated tryptase level. Five of 7 patients retested became ST+ before the second desensitization. Carboplatin desensitization was successfully completed in 105 of 106 (99%) treatment courses.nnnCONCLUSIONSnThe timing of carboplatin ST in relation to initial HSR is vital for risk stratification and subsequent desensitization. Initial ST- patients with a remote history of HSR are at high risk for conversion to ST+ and can develop more severe HSR.

CDDO-Me, a synthetic triterpenoid, inhibits expression of IL-6 and Stat3 phosphorylation in multi-drug resistant ovarian cancer cells

Previous studies have identified interleukin 6 (IL-6) as an important cytokine with prognostic significance in ovarian cancer. Activation of the IL-6-Stat3 pathway contributes to tumor cell growth, survival and drug resistance in several cancers, including ovarian cancer. To explore potential therapeutic strategies for interrupting signaling through this pathway, we assessed the ability of CDDO-Me, a synthetic triterpenoid, to inhibit IL-6 secretion, Stat3 phosphorylation, Stat3 nuclear translocation and paclitaxel sensitivity in several cell line model systems. These studies demonstrated that CDDO-Me significantly inhibits IL-6 secretion in paclitaxel-resistant ovarian cancer cells and specifically suppresses IL-6- or oncostatin M-induced Stat3 nuclear translocation. Treatment with CDDO-Me significantly decreases the levels of Stat3, Jak2, and Src phosphorylation in ovarian and breast cancer cell lines with constitutively activated Stat3. This inhibition of the IL-6-Stat3 pathway correlated with suppression of the anti-apoptotic Stat3 target genes Bcl-XL, survivin, and Mcl-1, and with apoptosis induction as measured by monitoring PARP and its cleavage product, as well as by quantitative measurement of the apoptosis-associated CK18Asp396. Furthermore, CDDO-Me increases the cytotoxic effects of paclitaxel in the paclitaxel-resistant ovarian cancer cell line OVCAR8TR (2 to 5-fold) and of cisplatin in the cisplatin-resistant ovarian cancer cell line A2780cp70 (2 to 4-fold). Our data confirm that CDDO-Me interrupts the signaling of multiple kinases involved in the IL-6-Stat3 and Src signaling pathways. Inhibition is likely achieved through multiple points within these pathways. In a model system of established acquired drug resistance, CCDO-Me is effective at partially reversing the drug-resistance phenotype.

Phase II study of intraperitoneal recombinant interleukin-12 (rhIL-12) in patients with peritoneal carcinomatosis (residual disease < 1 cm) associated with ovarian cancer or primary peritoneal carcinoma.

BackgroundPharmacokinetic advantages of intraperitoneal (IP) rhIL-12, tumor response to IP delivery of other cytokines as well as its potential anti-angiogenic effect provided the rationale for further evaluation of IPrhIL-12 in patients with persistent ovarian or peritoneal carcinoma.MethodsA phase 2 multi-institutional trial (NCI Study #2251) of IP rIL-12 (300 nanogram/Kg weekly) was conducted in patients with ovarian carcinoma or primary peritoneal carcinoma.Patients treated with primary therapy for ovarian cancer who had no extraabdominal/parenchymal disease or bulky peritoneal disease were eligible. Four to 8 weeks from last chemotherapy, eligible patients underwent a laparotomy/laparoscopy. Patients with residual disease ≤ 1 cm were registered for the treatment phase 2–5 weeks post surgery. The effect of IP rIL-12 on the expression of TNFα , INFα , IL-10, IP-10, IL-8, FGF, VEGF was also studied.ResultsThirty-four patients were registered for the first screening phase of the study. Median age was 56.6 years (range: 31–71); 12 completed the second phase and were evaluable for response/toxicity. Performance scores of IL-12 treated patients were 0 (11 pts) and 1 (1 pt). There were no treatment related deaths, peritonitis or significant catheter related complications. Toxicities included grade 4 neutropenia (1), grade 3 fatigue (4), headache (2), myalgia (2), non-neutropenic fever (1), drug fever (1), back pain (1), and dizziness (1). The best response observed was SD. Two patients had SD and 9 had PD, and 1 was evaluable for toxicity only.Peritoneal fluid cytokine measurements demonstrated a ≥ 3 fold relative increase post-rhIL-12: IFN-γ, 5/5 pts; TNF-α , 1/5; IL-10, 4/5; IL-8, 5/5; and VEGF, 3/5. IP10 levels were increased in 5/5 patients. Cytokine response profiles suggest either NK or T-cell mediated effects of IP rhIL-12. Cytokine/chemokine results also suggest a pleiotropic response since proteins with potential for either anti-tumor (IFN-γ , IP-10) or pro-tumor growth effects (VEGF, IL-8) were detected.ConclusionIP IL-12 can safely be administered at this dose and schedule to patients after first line chemotherapy for ovarian/peritoneal carcinoma. The maximum response was stable disease. Future IP therapies with rhIL-12 will require better understanding and control of pleiotropic effects of IL-12.

Augmentation of Therapeutic Efficacy in Drug-Resistant Tumor Models Using Ceramide Coadministration in Temporal-Controlled Polymer-Blend Nanoparticle Delivery Systems

The development of multidrug resistance (MDR) is a major hindrance to cancer eradication as it renders tumors unresponsive to most chemotherapeutic treatments and is associated with cancer resurgence. This study describes a novel mechanism to overcome MDR through a polymer-blend nanoparticle platform that delivers a combination therapy of C6-ceramide (CER), a synthetic analog of an endogenously occurring apoptotic modulator, together with the chemotherapeutic drug paclitaxel (PTX), in a single formulation. The PTX/CER combination therapy circumvents another cellular mechanism whereby MDR develops, by lowering the threshold for apoptotic signaling. In vivo studies in a resistant subcutaneous SKOV3 human ovarian and in an orthotopic MCF7 human breast adenocarcinoma xenograft showed that the PTX and CER nanoparticle combination therapy reduced the final tumor volume at least twofold over treatment with the standard PTX therapy alone. The study also revealed that the cotherapy accomplished this enhanced efficacy by generating an enhancement in apoptotic signaling in both tumor types. Additionally, acute evaluation of safety with the combination therapy did not show significant changes in body weight, white blood cell counts, or liver enzyme levels. The temporal-controlled nanoparticle delivery system presented in this study allows for a simultaneous delivery of PTX + CER in breast and ovarian tumor model drug, leading to a modulation of the apoptotic threshold. This strategy has tremendous potential for effective treatment of refractory disease in cancer patients.

Multidrug resistance-linked gene signature predicts overall survival of patients with primary ovarian serous carcinoma

Purpose: This study assesses the ability of multidrug resistance (MDR)–associated gene expression patterns to predict survival in patients with newly diagnosed carcinoma of the ovary. The scope of this research differs substantially from that of previous reports, as a very large set of genes was evaluated whose expression has been shown to affect response to chemotherapy. Experimental Design: We applied a customized TaqMan low density array, a highly sensitive and specific assay, to study the expression profiles of 380 MDR-linked genes in 80 tumor specimens collected at initial surgery to debulk primary serous carcinoma. The RNA expression profiles of these drug resistance genes were correlated with clinical outcomes. Results: Leave-one-out cross-validation was used to estimate the ability of MDR gene expression to predict survival. Although gene expression alone does not predict overall survival (OS; P = 0.06), four covariates (age, stage, CA125 level, and surgical debulking) do (P = 0.03). When gene expression was added to the covariates, we found an 11-gene signature that provides a major improvement in OS prediction (log-rank statistic P < 0.003). The predictive power of this 11-gene signature was confirmed by dividing high- and low-risk patient groups, as defined by their clinical covariates, into four specific risk groups on the basis of expression levels. Conclusion: This study reveals an 11-gene signature that allows a more precise prognosis for patients with serous cancer of the ovary treated with carboplatin- and paclitaxel-based therapy. These 11 new targets offer opportunities for new therapies to improve clinical outcome in ovarian cancer. Clin Cancer Res; 18(11); 3197–206. ©2012 AACR.

Integrated analysis of multiple microarray datasets identifies a reproducible survival predictor in ovarian cancer.

Background Public data integration may help overcome challenges in clinical implementation of microarray profiles. We integrated several ovarian cancer datasets to identify a reproducible predictor of survival. Methodology/Principal Findings Four microarray datasets from different institutions comprising 265 advanced stage tumors were uniformly reprocessed into a single training dataset, also adjusting for inter-laboratory variation (“batch-effect”). Supervised principal component survival analysis was employed to identify prognostic models. Models were independently validated in a 61-patient cohort using a custom array genechip and a publicly available 229-array dataset. Molecular correspondence of high- and low-risk outcome groups between training and validation datasets was demonstrated using Subclass Mapping. Previously established molecular phenotypes in the 2nd validation set were correlated with high and low-risk outcome groups. Functional representational and pathway analysis was used to explore gene networks associated with high and low risk phenotypes. A 19-gene model showed optimal performance in the training set (median OS 31 and 78 months, p<0.01), 1st validation set (median OS 32 months versus not-yet-reached, pu200a=u200a0.026) and 2nd validation set (median OS 43 versus 61 months, pu200a=u200a0.013) maintaining independent prognostic power in multivariate analysis. There was strong molecular correspondence of the respective high- and low-risk tumors between training and 1st validation set. Low and high-risk tumors were enriched for favorable and unfavorable molecular subtypes and pathways, previously defined in the public 2nd validation set. Conclusions/Significance Integration of previously generated cancer microarray datasets may lead to robust and widely applicable survival predictors. These predictors are not simply a compilation of prognostic genes but appear to track true molecular phenotypes of good- and poor-outcome.

Rare epithelial tumors arising in or near the ovary: a review of the risk factors, presentation, and future treatment direction for ovarian clear cell and mucinous carcinoma.

Currently all advanced-stage epithelial ovarian cancers are treated with a total abdominal hysterectomy, bilateral oophorectomy, and complete tumor debulking surgery, followed by carboplatin and paclitaxel. This treatment recommendation is based on clinical trials that are mostly populated with women with high-grade serous carcinomas. Patients with mucinous or clear cell carcinomas of the ovary tend to present with earlier-stage disease, and may not require adjuvant chemotherapy; those with advanced-stage disease tend to have carboplatin-resistant disease. Patients with mucinous ovarian carcinoma have presentations and tumor biology that are similar to colorectal carcinomas and may benefit from colorectal regimens containing fluorouracil (FU) and oxaliplatin. Their tumors may also be KRAS wild-type or have HER2 amplification, and could benefit from drugs like cetuximab or trastuzumab. Patients with clear cell carcinoma of the ovary often harbor AIRD1a mutations, an early event in oncogenesis that is not a currently drugable target. Anecdotal cases and our biologic understanding of these malignancies suggest they might be preferentially sensitive to antiangiogenesis inhibitors. Focused international trials will be needed in both of these rare epithelial ovarian cancers to better define optimal treatment regimens.

Abstract LB-51: Correlation of expression of MDR-associated genes with outcome in primary ovarian serous carcinoma

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DCnnWe have been developing tools to reproducibly correlate the expression of multidrug-resistance (MDR)-associated genes with response to chemotherapy in primary cancers. This study reports the results of a novel MDR gene expression analysis of primary serous carcinoma of the ovary utilizing a TaqMan Low Density Array (TLDA) chip which includes 380 previously characterized multidrug resistance (MDR)-associated genes that were initially identified in cultured cancer cells. Primary tumor samples from 133 patients from 4 sites were studied. All patients were subsequently treated with standard chemotherapy and had known clinical outcome. A 13 gene signature was identified whose expression added statistical power to the risk status of the patients based on standard clinical parameters (age, CA125, and success of surgical debulking) (log-rank statistic p=0.02). When subsets of patients with defined clinical risk were studied, we found that a subset of clinically high risk patients that had low expression of the 13 gene signature had a better outcome than would be predicted by purely clinical criteria. Similarly, clinically low risk patients with high expression of the 13 gene signature had a poorer prognosis. Since the mechanism of action of the 13 MDR genes involved in the signature are well-understood, it might be possible to devise therapeutic strategies to some of these targets with the goal of improving clinical outcome.nnCitation 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 LB-51.