Late-stage Ovarian Cancer Patients Research Articles

Abstract 7154: Ivospemin/doxorubicin combination modulates polyamine metabolism to improve survival in murine ovarian cancer models

Abstract Polyamines are small polycationic alkylamines that are absolutely required for the continual growth and proliferation of cancer cells. As cancer cells maintain elevated polyamine pools through dysregulated polyamine metabolism, its pharmacological modulation is a promising avenue in cancer therapeutics. The polyamine analogue ivospemin has shown efficacy in slowing pancreatic and ovarian tumor progression in vitro and in vivo and has demonstrated encouraging results in pancreatic cancer clinical trials. Considering nearly 75% of late-stage ovarian cancer patients develop resistant to platinum-based chemotherapies, limiting treatment options, the aim of our study is to determine the potential efficacy of ivospemin in combination with doxorubicin, a common chemotherapeutic used in platinum-resistant ovarian tumors. We have previously shown that ivospemin exposure decreases polyamine content in a variety of cancer cell lines through downregulation of the polyamine biosynthetic enzyme ornithine decarboxylase (ODC) and induction of the polyamine catabolic enzyme spermidine/spermine-N1-acetyltransferase (SSAT). Here we examine the potential of combining ivospemin with doxorubicin. Ivospemin treatment reduces cell viability in ovarian adenocarcinoma cell lines and increases the toxicity of doxorubicin regardless of cisplatin sensitivity. Cells treated with the combination exhibit a greater decrease in polyamine levels than cells treated with either single agent. This increased polyamine depletion and decreased survival is accomplished through modulation of polyamine metabolism, predominately through an additive induction of SSAT activity. Using the syngeneic VDID8+ ovarian murine model, we further evaluated the ability of ivospemin to improve response to doxorubicin at clinical and sub-clinical dosing. Ascites fluid was used as a marker for tumor burden and evaluated for polyamine content. We found that the combination treatment increases median survival, delays tumor onset, and decreases overall tumor burden compared to either clinical or subclinical doxorubicin dosing schemes. Combination treatment also decreases overall polyamine content in the ascites by 75%. N1-acetylated spermidine is enriched in ascites from combination-treated mice, consistent with an upregulation of SSAT in response to treatment. Recognizing the non-representative mutational status of the VDID8+ model as a limitation, we are currently evaluating the combination of ivospemin and doxorubicin in genetically defined murine models that better recapitulate human high-grade serous ovarian carcinomas. Ongoing studies will determine influences on the tumor microenvironment and will mechanistically evaluate the cooperativity of ivospemin and doxorubicin on pathways outside of polyamine metabolism. Citation Format: Cassandra E. Holbert, Jackson R. Foley, Ashley C. Nwafor, Ting-Ann Liu, Elizabeth Bruckheimer, Jennifer K. Simpson, Tracy Murray Stewart, Robert A. Casero. Ivospemin/doxorubicin combination modulates polyamine metabolism to improve survival in murine ovarian cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7154.

Ovarian Cancer in Iran: National Based Study.

Ovarian cancer (OC) is the 7th most common cancer, with 239,000 new cases per year. In Iran, it is the 8th most common cancer, with an ASIR of 3.9/100,000 women. The 5-year overall survival in Iran based on previous studies is about 61% which in comparison with eastern countries has better survival. The study included patients from the Iran National Cancer Registry from 2009-2014. Several steps were taken to control data quality. This study used a Kaplan-Meier survival curve to compare OC survival rates across geographical, pathological, and other variables. All analyses were done in R (4.02) and SPSS (26), with a 0.05 P-value considered statistically significant. The study enrolled 7977 cases of OC. OC's ASIR was 4.10/100,000. In epithelial and non-specific OC, ASIR was >0.5. Five-year survival was 55% and 10-year survival was 45%. OC is the 8th most common cancer in Iran, with lower age-specific incidence and better overall survival than East Asia and North America. In Iran, as in Eastern Europe, OC incidence correlated with reduced total fertility rate and population aging. Five and 10-year overall survival rates were 55% and 44%, respectively, higher than the West. This may be because late stage OC patients are excluded from pathology and classified as "undiagnosed" in death certificates or hospitalization files.

Optimization of Extracellular Flux Assay to Measure Respiration of Anchorage-independent Tumor Cell Spheroids.

Three-dimensional (3D) cell culture models are widely used in tumor studies to more accurately reflect cell-cell interactions and tumor growth conditions in vivo. 3D anchorage-independent spheroids derived by culturing cells in ultra-low attachment (ULA) conditions is particularly relevant to ovarian cancer, as such cell clusters are often observed in malignant ascites of late-stage ovarian cancer patients. We and others have found that cells derived from anchorage-independent spheroids vary widely in gene expression profiles, proliferative state, and metabolism compared to cells maintained under attached culture conditions. This includes changes in mitochondrial function, which is most commonly assessed in cultured live cells by measuring oxygen consumption in extracellular flux assays. To measure mitochondrial function in anchorage-independent multicellular aggregates, we have adapted the Agilent Seahorse extracellular flux assay to optimize measurements of oxygen consumption and extracellular acidification of ovarian cancer cell spheroids generated by culture in ULA plates. This protocol includes: (i) Methods for culturing tumor cells as uniform anchorage-independent spheroids; (ii) Optimization for the transfer of spheroids to the Agilent Seahorse cell culture plates; (iii) Adaptations of the mitochondrial and glycolysis stress tests for spheroid extracellular flux analysis; and (iv) Suggestions for optimization of cell numbers, spheroid size, and normalization of oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) values. Using this method, we have found that ovarian cancer cells cultured as anchorage-independent spheroids display altered mitochondrial function compared to monolayer cultures attached to plastic dishes. This method allows for the assessment of mitochondrial function in a more relevant patho/physiological culture condition and can be adapted to evaluate mitochondrial function of various cell types that are able to aggregate into multicellular clusters in anchorage-independence. Graphic abstract: Workflow of the Extracellular Flux Assay to Measure Respiration of Anchorage-independent Tumor Cell Spheroids.

Abstract 568: Nanonets for multiomics blood analysis and cancer biomarker discovery

Abstract Despite the tremendous potential of liquid biopsies to revolutionise cancer care, there has been limited success translating blood-circulating proteomic and genomic biomarkers into the clinic. This is fundamentally due to the extremely low concentration of tumour-derived biomolecules in blood circulation, particularly at an early disease stage, which makes the discovery phase of the biomarker pipeline extremely challenging. Nanotechnology offers a promising solution, with a nanoparticle-biomolecule enrichment tool recently developed to enrich low-abundant, low molecular weight proteins in the blood of ovarian cancer patients.[1] Proteomic analysis followed by immunoassay-based validation of selected proteins demonstrated the potential of the nanoparticle-platform proposed to discover novel biomarkers with greater specificity and sensitivity than the clinically used biomarkers. In addition, we recently confirmed the presence of cell-free DNA (cfDNA) captured onto the surface lipid nanoparticles incubated ex vivo with human plasma.[2] A significantly higher abundance of cfDNA was detected in the nanoparticle-enriched plasma samples of late-stage ovarian cancer patients compared to age-matched female controls. Proteomic analysis of the same samples also revealed tumour-specific elevations in histone proteins, which are commonly found in circulation complexed with cfDNA. These findings have highlighted the opportunity for the development of a nano-proteogenomics platform able to simultaneously purify both proteins and cell-free nucleic acids from human plasma, an important step in the discovery of novel multi-omic biomarker panels. Utilising the above patented nanotechnology, we have compared proteomic and genomic profiles derived from nanoparticle-biomolecule samples of cancer patients with age- and sex-matched controls to uncover new potential blood-based biomarkers in a proof-of-principle study. In brief, ex-vivo plasma samples were incubated with lipid-based nanoparticles and purified using a two-step size-based purification protocol. The purified samples were then analysed by label-free proteomics (LC-MS/MS) and next-generation sequencing to uncover both proteomic and genomic tumour-specific signatures, including differentially abundant proteins, genomic copy number alterations and tumour-specific mutations. This work highlights the potential of our nanotechnology-based enrichment platform to enhance the discovery of cancer-specific proteogenomic biomarker panels, a vital step in developing sensitive and specific liquid biopsies for the early detection of cancer.

Abstract 304: Peptide-mediated delivery of siRNAs targeting CSNK2A1 decreases migration of ovarian cancer cells in vitro

Abstract Background Ovarian cancer (OC) is among the most commonly diagnosed cancers and combined with the low responses to therapeutics, it has the highest mortality among gynecological cancers. When diagnosed at stage III and stage IV, survival rates remain below 30%. Over 90% of ovarian cancers are epithelial-based, resulting in proliferation with both local and distant metastasis. Common modes of treatment typically include surgical debulking and platinum-based chemotherapies. However, approximately 80% of confirmed late-stage OC patients will encounter recurrence, multidrug resistance, or metastasis. As a result, there is a need for more effective treatments by means of sustainable therapeutics. RNA interference (RNAi)- based therapies via short interfering RNA (siRNA) have shown promise a potential treatment method. However, siRNAs cannot readily enter the cell due to their large size and negative charge. Thus, siRNAs must be combined with a carrier that maintains the efficacy of the therapeutic by promoting membrane interaction, internalization, and release of siRNAs. Fusogenic peptides (FPs) serve as efficient carriers by complexing with siRNAs through electrostatic interactions and mediating endosomal escape to maintain bioactivity. Here, we investigate the use of a novel FP for the delivery of siRNAS targeting CSNK2A1 and characterize ovarian cancer cell response. Methods OVCAR3 human ovarian cancer cells were treated with fusogenic peptides complexed with either non-targeting siRNAs or siRNAs targeting CSNK2A1 at varying nitrogen to phosphorus (N:P) ratios and downstream cellular analysis was conducted. Cytotoxicity of both the fusogenic peptide vehicle alone and peptide/siRNA complexes was determined using MTS assays. The effect of the peptide/siRNA complex on ovarian cancer cell migration was measured using a scratch wound healing assays. Results The FP vehicle displayed no significant decreases in cell viability at higher N:P ratios. This result indicates that the FP vehicle is not cytotoxic to the cells and demonstrate the potential biocompatibility of the delivery system. In the scratch wound healing assay, percent wound healing was substantially decreased when ovarian cancer cells were treated with peptide complexed with siRNAs targeting CSNK2A1 in contrast to treatment with peptide complexed with non-targeting siRNAs. Higher N:P ratios displayed an overall greater decrease in wound healing. In future studies, we will examine whether peptide/siRNA complexes affect the invasiveness of ovarian cancer cells. Citation Format: Anthony Hazelton, Timothy Samec, Jessica Boulos, Serena Gilmore, Angela Alexander-Bryant. Peptide-mediated delivery of siRNAs targeting CSNK2A1 decreases migration of ovarian cancer cells in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 304.

Phase 1A clinical trial of the first-in-class fascin inhibitor NP-G2-044 evaluating safety and anti-tumor activity in patients with advanced and metastatic solid tumors.

2548 Background: Fascin inhibitors block tumor metastasis and increase antigen uptake in intra-tumoral dendritic cells. Filopodia, finger-like protrusions on cell surfaces, are necessary for migration of metastatic tumor cells and intra-tumoral dendritic cells. Fascin is the primary actin cross-linker in filopodia and elevated levels correlate with increased risk of metastasis, disease progression and mortality. NP-G2-044 is a novel small molecule that inhibits function of fascin. Pre-clinical data demonstrate drug-associated reductions in tumor growth and metastasis, enhanced immune response and survival in treated animals, and drug-drug synergism when combined with anti-PD-1 antibodies. Methods: This multicenter phase 1A clinical trial was designed to evaluate safety and tolerability of NP-G2-044 and to identify the drug’s recommended phase 2 dose (RP2D) using a 3+3 dose escalation design. NP-G2-044 was administered to patients (pts.) with treatment-refractory solid tumor malignancies as a single oral daily dose for 6-week cycles that included 4 weeks on (daily dosing) and 2 weeks off (rest). Results: A total of 23 pts. were enrolled in 7 dose cohorts ranging from 200-2100 mg. QD. Overall, NP-G2-044 appeared well-absorbed and distributed with Tmax of ̃4 hrs and T1/2 of 20-24 hrs. Across all cohorts, no DLTs, drug-related SAEs or patient deaths were observed. Based on PK and safety findings, 1600 mg. daily was selected as the provisional RP2D. While no formal RECIST-based objective responses were observed, consistent with the drug’s non-cytotoxic mechanism of action, preliminary signals of anti-tumor and anti-metastatic activity were observed. These include dose proportional increases in duration of treatment, progression-free-survival, and metastasis-free interval, in particular for 4/4 late-stage ovarian cancer patients (table). Comparison of time on treatment (TOT) for ovarian cancer patients. Conclusions: In this first-in-human clinical trial, the novel fascin inhibitor, NP-G2-044, appeared safe and well tolerated. Signals of single-drug anti-tumor and anti-metastatic activity were observed. A phase 2A clinical trial with a particular focus on Ovarian Cancer will seek to elucidate signals of RP2D activity in both monotherapy and the combination of NP-G2-044 with anti-PD-(L)1 immune checkpoint inhibitors. Clinical trial information: NCT03199586. [Table: see text]

MALDI Mass Spectrometry Imaging of Early‐ and Late‐Stage Serous Ovarian Cancer Tissue Reveals Stage‐Specific N‐Glycans

Epithelial ovarian cancer is one of the most fatal gynecological malignancies in adult women. As studies on protein N-glycosylation have extensively reported aberrant patterns in the ovarian cancer tumor microenvironment, obtaining spatial information will uncover tumor-specific N-glycan alterations in ovarian cancer development and progression. matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is employed to investigate N-glycan distribution on formalin-fixed paraffin-embedded ovarian cancer tissue sections from early- and late-stage patients. Tumor-specific N-glycans are identified and structurally characterized by porous graphitized carbon-liquid chromatography-electrospray ionization-tandem mass spectrometry (PGC-LC-ESI-MS/MS), and then assigned to high-resolution images obtained from MALDI-MSI. Spatial distribution of 14 N-glycans is obtained by MALDI-MSI and 42 N-glycans (including structural and compositional isomers) identified and structurally characterized by LC-MS. The spatial distribution of oligomannose, complex neutral, bisecting, and sialylated N-glycan families are localized to the tumor regions of late-stage ovarian cancer patients relative to early-stage patients. Potential N-glycan diagnostic markers that emerge include the oligomannose structure, (Hex)6 + (Man)3 (GlcNAc)2 , and the complex neutral structure, (Hex)2 (HexNAc)2 (Deoxyhexose)1 + (Man)3 (GlcNAc)2 . The distribution of these markers is evaluated using a tissue microarray of early- and late-stage patients.

Network of Mediators for Vascular Inflammation and Leakage Is Dysbalanced during Cytoreductive Surgery for Late-Stage Ovarian Cancer.

Background Cytoreductive surgery (CS) in late-stage ovarian cancer patients is often challenging due to extensive volume shifts, and high fluid intake may provoke postoperative complications. Expression of vasoactive mediators is altered in cancer patients, which may affect systemic vascular function. We sought to assess how serum levels of vasoactive markers and mediators change during CS in ovarian cancer. Methods Following IRB approval and informed consent, pre- and postoperative serum samples were analyzed in 26 late-stage ovarian cancer patients using multiplex protein arrays and ELISA. Results The proinflammatory cytokines and chemokines IL-6, IL-8, and CCL2 were significantly elevated after 24 hrs compared to the baseline values, with IL-6 and IL-8 being most prominently increased. While ANGPT1 remained unchanged after surgery, its competitive antagonist ANGPT2 was significantly increased. In contrast, serum levels of the ANGPT receptor TIE2 were decreased to 0.6 of the baseline values. While VEGF-D, E-selectin, P-selectin, ICAM-1, and PECAM-1 remained unchanged, serum activity of both thrombomodulin and syndecan-1 was significantly increased following surgery. Conclusion We identified a regulatory network of acute-phase reaction during CS in late-stage ovarian cancer. This suggests that IL-6 exerts positive regulation of other proinflammatory mediators and, by upregulating ANGPT2 and suppressing ANGPT1, induces a serum profile that promotes vascular leakage. This may contribute to the observed hemodynamic alterations during CS procedures.

Tumor-intrinsic PD-L1 regulates tumor initiating cell virulence and stemness genes, and TCF1+ stem-like T cells through Raptor in ovarian cancer, which correlates with survival in high grade serous ovarian cancer

Abstract We reported that tumor intrinsic PD-L1 promotes tumor initiating cell (TIC) virulence and mTORC1. Others have focused on PI3K/AKT/mTOR in promoting TIC, but specific downstream mTOR regulators of tumor stemness are unknown. We knocked down Raptor (mTORC1 component, Rptorlo) in ID8agg cells (murine ovarian cancer). Rptorlo cells had reduced mTORC1 with no change in PD-L1 in total cells or CD44+CD24+ TIC. %TIC was reduced in Rptorlo cell cultures, and Rptorlo TIC were functionally defective for self-renewal by tumorosphere formation. Rapamycin (mTORC1 inhibitor) reduced ID8agg Rptor, tumorospheres, and the stemness and virulence genes Oct4 and Nanog. Oct4 knockin to PD-L1lo ID8agg restored TIC numbers and spheres. Together, data confirm PD-L1 drives stemness through Oct4 by increasing mTORC1. Rptorlo TIC formed significantly smaller tumors vs. control TIC in immunodeficient NSG mice, confirming TIC intrinsic Rptor drives immune independent virulence. In wild type mice, Rptorlo vs. control TIC produced less ascites and smaller tumors with lower %TIC in vivo (but similar PD-L1), significantly more recently-activated CD44hiCD62LloCD8+ cells in ascites and draining lymph nodes (DLN). CCR2+CD8+ T cells and CXCR5+TCF1+PD-1+Tim3− stem-like T cells were also increased in Rptorlo DLN. Thus, Rptorlo TIC influence systemic and tumor-associated immunity. In high grade serous ovarian tumors (The Cancer Genome Atlas) high Rptor expression predicted a significantly higher cancer stem cell signature, and lower median survival in late stage patients. Our work establishes tumor intrinsic Rptor driven by PD-L1 plays a key role in regulating TIC and stem like T cells and can be a prognostic marker for late stage ovarian cancer patients.

Ovarian tumours of different histologic type and clinical stage induce similar changes in lipid metabolism

BackgroundPrevious results obtained from serum samples of late-stage, high-grade serous ovarian carcinoma patients showed large alterations in lipid metabolism. To validate and extend the results, we studied lipidomic changes in early-stage ovarian tumours. In addition to serous ovarian cancer, we investigated whether these changes occur in mucinous and endometrioid histological subtypes as well.MethodsAltogether, 354 serum or plasma samples were collected from three centres, one from Germany and two from Finland. We performed lipidomic analysis of samples from patients with malignant (N = 138) or borderline (N = 25) ovarian tumours, and 191 controls with benign pathology. These results were compared to previously published data.ResultsWe found 39 lipids that showed consistent alteration both in early- and late-stage ovarian cancer patients as well as in pre- and postmenopausal women. Most of these changes were already significant at an early stage and progressed with increasing stage. Furthermore, 23 lipids showed similar alterations in all investigated histological subtypes.ConclusionsChanges in lipid metabolism due to ovarian cancer occur in early-stage disease but intensify with increasing stage. These changes occur also in other histological subtypes besides high-grade serous carcinoma. Understanding lipid metabolism in ovarian cancer may lead to new therapeutic and diagnostic alternatives.

Abstract POSTER-CTRL-1203: Circulating TP53 mutations as a biomarker of high-grade serous cancer

Abstract Women who carry a germline BRCA1 or BRCA2 mutation are at high risk of developing ovarian cancer in their lifetime. While risk can be reduced by prophylactic bilateral salpingo-oopherectomy (RRSBO), for those high-risk women who delay, or choose not to undergo RRSBO, current surveillance options have not shown sufficient specificity or sensitivity to prevent an advanced stage diagnosis (Buys et al (2011) JAMA). As such there is a need to identify novel, sensitive biomarkers to employ in this at-risk population. We recently found that BRCA1/2 mutation carriers predominantly develop high-grade serous cancers (HGSC) (Alsop et al (2012) J Clin Oncol), therefore, identifying a biomarker of HGSC will be useful for screening BRCA1/2 carriers. Mutation in TP53 represents the ideal biomarker of HGSC; mutation occurs early in tumour development (Crum et al (2007) Clin Med Res), it is present in almost 100% of tumours (Ahmed, et al (2010) J Pathol, TCGA (2011) Nature), and pathogenic mutations can be readily distinguished from passengers (Olivier et al (2010) Cold Spring Harb Perspect Biol). Tumour specific TP53 mutations have been identified in the circulating DNA of late stage ovarian cancer patients by Sanger sequencing (Swisher et al (2005) Am J Obstet Gynecol). Next generation sequencing (NGS) provides increased sensitivity for identification of rare mutant alleles (Flaherty et al (2011) Nucl Acids Res) and has been used to monitor disease burden in advanced stage cases (Murtaza et al (2013) Nature). Supported by a Marsha Rivkin Challenge Grant, we explored the feasibility of detecting free circulating mutant TP53 DNA in plasma from HGSC patients, using multiplex PCR to amplify TP53 DNA from the circulating DNA followed by ultra-deep NGS. The main challenge has been in developing bioinformatics filtering processes to increase specificity and sensitivity. We utilised multiple variant callers to identify low frequency, high quality, pathogenic variants that are then compared to the IARC TP53 database and COSMIC. Variants called in our sequence data that are absent from these databases are flagged as lower confidence calls. Consistent sequencing artefacts were removed from consideration. High confidence variants were tested for their presence in multiple amplicons, to generate a final list of variants ranked in terms of confidence based on multiple lines of bioinformatics evidence. Using this methodology, we have been able to detect tumour specific TP53 mutations in circulating DNA of 40% of predominately late stage cases. In those cases where the mutation was not called in the circulating DNA, the mutant allele frequency was less than 0.1% and could not be distinguished from the background errors associated with NGS. The extremely low frequency of mutations in the plasma of women with late stage HGSC, against a background of normal TP53 sequences, currently hampers immediate adoption of circulating TP53 mutations as an early detection biomarker. Our work provides proof of principle for the approach, however, we need to develop additional strategies to push detection into a range that is useful for screening at risk women. Citation Format: Elizabeth Christie, Tane Hunter, Maria Doyle, Australian Ovarian Cancer Study, David Bowtell. Circulating TP53 mutations as a biomarker of high-grade serous cancer [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-CTRL-1203.

Abstract 2706: Inhibition of PFKFB3/glycolysis overcomes chemoresistance in ovarian cancers

Abstract Metabolic alterations in cancer are increasingly being recognized as important novel targets. Among different regulators of altered metabolism, 6-PhosphoFructo-2-Kinase/Fructose-2,6-Bisphosphatases 3 (PFKFB3) a glycolytic enzyme required for tumorigenic growth, and produces fructose-2,6-bisphosphate (F2,6BP), is recognized as important regulator of glycolysis. We determined that the active form of PFKFB3ser471 was overexpressed in chemo-resistant ovarian cancer (OVCA) cell lines and resistant patient derived xenograft (PDX) models compared to their isogenic chemo-sensitive cell lines and sensitive PDX models. These results suggest that targeting PFKFB3 will have beneficial effects in patients with OVCA. PFK-158 is a potent and selective inhibitor of PFKFB3 that is currently being investigated in a Phase 1 study in patients with advanced solid malignancies. Here we report for the first time, PFK-158 dose-dependently inhibits cell proliferation and colony formation ability in both carboplatin and paclitaxel (PTX) resistant cell lines. PFK-158 markedly suppresses glycolysis by reducing glucose uptake, ATP production, lactate dehydrogenase activity and lactate secretion. Interestingly, both Chou-Talalay synergy analysis and apoptosis assay by annexin V-PI staining showed PFK-158 strongly synergies with both PTX and carboplatin in PTX and cisplatin resistant cell lines respectively. PFK-158 induced apoptosis through a significant increase in caspase-3/7 activation and PARP cleavage. Moreover, in a highly metastatic PTX-resistant in vivo model, combination of PFK-158 with carboplatin and PTX significantly reduced tumor weight, ascites and metastasis compared to untreated and PFK-158, carboplatin or PTX alone treated mice. Since the majority of OVCA patients recur with chemo-resistant disease, our results suggest that PFK-158 in combination with standard chemotherapy may have clinical utility in late stage ovarian cancer patients. Citation Format: Susmita Mondal, Debarshi Roy, Eleftheria Kalogera, Ashwani Khurana, Gilles H. Tapolsky, Sucheta Telang, Jason Chesney, Viji Shridhar. Inhibition of PFKFB3/glycolysis overcomes chemoresistance in ovarian cancers. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2706. doi:10.1158/1538-7445.AM2015-2706

Direct estimation of differential networks.

It is often of interest to understand how the structure of a genetic network differs between two conditions. In this paper, each condition-specific network is modeled using the precision matrix of a multivariate normal random vector, and a method is proposed to directly estimate the difference of the precision matrices. In contrast to other approaches, such as separate or joint estimation of the individual matrices, direct estimation does not require those matrices to be sparse, and thus can allow the individual networks to contain hub nodes. Under the assumption that the true differential network is sparse, the direct estimator is shown to be consistent in support recovery and estimation. It is also shown to outperform existing methods in simulations, and its properties are illustrated on gene expression data from late-stage ovarian cancer patients.

Benefit of palliative chemotherapy and hospice enrollment in late-stage ovarian cancer patients

The ideal timing for transition to best supportive care (BSC) for ovarian cancer patients is not clear. We retrospectively assessed the survival benefit of continuing chemotherapy and hospice enrollment in late-stage ovarian cancer patients. Eligibility criteria included platinum and taxane treatment, clinical progression within 6 months of the last platinum dose, and progression during chemotherapy. Of the 55 eligible patients (median overall survival after first becoming refractory [1st Ref], 96 days), 22 received chemotherapy (Chemo group), two received radiation therapy, and 13 had medical contraindications for subsequent chemotherapy. The remaining 18 patients (BSC group) were compared with the Chemo group. The Chemo and BSC groups had similar background characteristics, except for the rate of consultation with a regional palliative care physician before or within 1 week of 1st Ref (9% vs 50%, respectively). In multivariate analysis, chemotherapy (hazard ratio 0.251, P = 0.005) and hospice enrollment (hazard ratio, 0.274, P = 0.023) were predictive factors of survival after 1st Ref. Chemotherapy after 1st Ref can be offered and hospice enrollment during the terminal stages is encouraged for recurrent ovarian cancer patients.

Biophysical Basis of Drug Resistance in Epithelial Ovarian Cancers

Ovarian cancer is one of the most deadly malignancies in women owing to diagnosis at an advanced stage. A major limiting factor in treating late-stage ovarian cancer patients is attributed to chemoresistance against drugs like cisplatin and paclitaxel. Though alterations in physical properties of the tumor microenvironment in a variety of different epithelial cancers, including ovarian cancer, is well appreciated, how such alterations influence normal versus drug-resistant cells remains obscure. In this study, we have compared the behaviour of normal and cisplatin-resistant ovarian cancer cells in response to changes in extracellular matrix (ECM) density. In comparison to control cells, cisplatin-resistant cells were less spread, possessed less number of cell matrix adhesions, and lower degradation potential. Further, cisplatin-resistant cells were found to possess higher baseline contractility compared to normal ovarian cancer cells, as assessed by trypsin de-adhesion assay. However, the enhanced contractility of cisplatin-resistant cells remained insensitive to changes in ECM density. Western blots revealed lower expression levels of the focal adhesion protein vinculin and higher expression levels of the actin crosslinking protein α-actinin in cisplatin-resistant cells compared to control cells. Together, our results point to a potential mesenchymal to amoeboidal transition in ovarian cancer cells that attain drug resistance.Key Words: chemoresistance, tumor microenvironment, extracellular matrix, contractility, focal adhesions, actin bundling proteins.

Abstract 3274: Development of a clinically relevant in vivo model of ovarian cancer tumorgrafts in immunodeficient mice

Abstract Despite advances in chemotherapeutic options over the last four decades, ovarian cancer remains the most lethal gynecologic malignancy with a cure rate that is essentially unchanged. A major barrier is lack of treatment-naïve, clinically- relevant in vivo models of epithelial ovarian cancer (EOC). To target this problem, we have developed low-passage in vivo models of EOC derived from patient primary debulking procedures at Mayo Clinic (Rochester, MN). Tumors were obtained from consented patients with suspected ovarian cancer, minced and injected into severe combined immunodeficiency (SCID) mice intraperitoneally for model establishment. To the date, we have heterotransplanted 129 EOC or ovarian malignant mixed mullerian (MMMT) tumors. The most common histologic subtype is serous (70.5%), followed by endometrioid (12.4%), clear cell (6.9%), and others (9.9%). The tumors were injected intraperitoneally into severe combined immunodeficiency (SCID) mice and the average time to moribund (TTM) was 174 +/− 83 days. In general, tumors grew faster with serial passages, TTM for epithelial tumors was 87 +/− 15 days and 19.5 +/− 3 days for MMMT. De novo ascites developed in 17 models and 24 models developed bowel metastasis, two clinically-relevant complications in late-stage ovarian cancer patients. Tumorgrafts were histologically similar to their source patient tumors and were positive for expression epithelial markers (pan-cytokeratin). The engraftment rate was 72.4% (n=87) after ≤ 6 months of lead-time, which is the average time to tumorgraft harvest. Passage of well-established tumorgrafts in SCID mice was successful in 88.6 % (n= 70) of all mice but only 56% (n=16) of athymic nude mice, consistent with prior studies demonstrating improved engraftment rates in more immunodeficient mice. Molecular characterization of tumorgrafts by array comparative genomic hybridization revealed similar gains and losses between the patient, early-passage, and later-passage tumorgraft tissues, indicating the tumorgrafts were genetically similar to their primary tumor. Analysis of tumorgrafts using the Affymetrix Human Plus 2.0 arrays revealed a predominance of previously described molecular subtypes C3, C4, and C5. Current investigations with both standard chemotherapy and novel targeted therapies are ongoing. Taken together, these models are as diverse as the patient population from which they are derived, produce clinically-relevant complications of EOC, maintain genetic fidelity in SCID mice, and are useful preclinical models for testing and development of novel therapeutics for ovarian cancer. High rates of engraftment are feasible. These tumorgrafts may help define predictors of response and eventually, lead to better treatments for patients. This work is funded by the Mayo Ovarian SPORE (CA136393) and the Minnesota Ovarian Cancer Alliance. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3274. doi:1538-7445.AM2012-3274

Epitope presentation is an important determinant of the utility of antigens identified from protein arrays in the development of autoantibody diagnostic assays

Autoantibodies represent an attractive biomarker for diagnostic assays principally due to the stability of immunoglobulin in patient serum facilitating measurement with conventional assays. Immune responses to tumorigenesis may facilitate detection of ovarian cancer in the early stages of the disease with identification of a panel of tumour specific autoantibodies. Despite the reporting of many tumour associated autoantibodies using arrays of tumour antigens, this has not led to the advance in diagnostic capability as rapidly as was initially expected. Here we examine the potential diagnostic utility of candidate autoantibody biomarkers identified via screening of serum samples on a high content human protein array from a unique cohort of early stage and late stage ovarian cancer patients. We analyse the performance of autoantibodies to the tumour suppressor protein p53 and the novel autoantigens alpha adducin and endosulfine alpha identified in our array screen. Each antigen has different performance characteristics using conventional ELISA format and Western blot immunoassay. The high attrition rate of promising autoantigens identified by array screening can in part be explained by the presentation of the epitope of the antigen in the subsequent method of validation and this study provides directions on maximising the potential of candidate biomarkers. This article is part of a Special Issue entitled: Translational Proteomics.

Improving Psychological Adjustment Among Late-Stage Ovarian Cancer Patients: Examining the Role of Avoidance in Treatment

Data suggest that individuals dealing with a cancer diagnosis are less likely to suffer from depression, anxiety, and psychological distress when they cope with their condition from a stance of emotional and cognitive acceptance (e.g. Dunkel, et al., 1992; Stanton, et al., 2000). Although traditional CBT often includes some acceptance-oriented elements, recent variants of CBT, such as Acceptance and Commitment Therapy (ACT), have acceptance as a central focus. ACT targets emotional distress directly through acceptance of difficult thoughts and emotions. The current study is a preliminary comparison of ACT and treatment as usual (TAU) in the treatment of emotional distress among women with late-stage ovarian cancer. Forty-seven women diagnosed with Stage III or IV ovarian cancer were randomly assigned to one of two treatment conditions. Treatment consisted of 12 face-to-face meetings with a therapist, each following a TAU or ACT protocol. Results indicate that both groups showed improved mood and quality of life following the intervention. The ACT group showed significantly greater improvements compared to the TAU group. Furthermore, mediation analyses indicate that the effects of treatment were mediated by cognitive avoidance. Although the study is limited by the implementation of treatment in both conditions by a single therapist, the TAU group showed improvements that were consistent with effect sizes available in the literature, suggesting that the intervention was a credible and effective control treatment. These findings provide preliminary support for the use of ACT in ovarian cancer populations. Further work is needed to investigate the effectiveness in other oncology populations as well as investigate potential patient characteristics which may interact with these interventions.

Serum Profiling to Distinguish Early- and Late-Stage Ovarian Cancer Patients from Disease-Free Individuals

Sera mass spectrometry (MS) peak differences were analyzed from 35 ovarian cancer patients and 16 disease-free individuals. “Leave one out” cross validation was used to assign “% cancer peaks” in control and ovarian cancer sera samples. Sera MS discriminated stage I/II and stage III/V ovarian cancer patients versus controls with ROC curve area values of 0.82 and 0.92. Test sensitivities for ovarian cancer stage I/II and III/V were 80% and 93% respectively. These results indicate that MS is useful for distinguishing sera from early-stage ovarian cancer patients, and has potential as a test for early detection of this disease.

DNA-damage response gene polymorphisms and therapeutic outcomes in ovarian cancer

Epithelial ovarian cancer has a poor prognosis owing to late diagnosis and frequent relapse after first-line therapy. Analysis of individual genetic variability could aid in the identification of markers, which could help in stratifying patients with the aim of optimizing individual therapy. In this study we assessed polymorphisms in three genes important in drugs' response in 97 early and 235 late-stage ovarian cancer patients. The Asp1104His polymorphism in xpg, a gene important for removal of platinum adducts, was associated with progression-free survival in early- and late-stage ovarian cancer. Our data indicate that a simple diagnostic analysis such as xpg genotyping can help in predicting response, and extension to other possibly relevant genotypes could be useful in selecting patients with epithelial ovarian cancer for optimal therapy and hence increase the chance of response.