In Vivo and In Vitro Efficacy of Trastuzumab Deruxtecan in Uterine Serous Carcinoma

Uterine serous carcinoma (USC) is a rare, biologically aggressive variant of endometrial cancer with a high recurrence rate and poor prognosis. HER2 overexpression (3+ positivity) by IHC and/or FISH ERBB2 gene amplification is detected in approximately one-third of patients with USC. Clinical trials incorporating trastuzumab with standard chemotherapy have recently demonstrated improved progression-free and overall survival in advanced-stage or recurrent USC that overexpresses HER2. However, a large number of patients with USC eventually developed resistance to trastuzumab. Trastuzumab deruxtecan (T-DXd) is a novel HER2-directed antibody-drug conjugate with a topoisomerase I inhibitor payload recently approved by the Food and Drug Administration (FDA) for multiple tumor indications. Here, we investigated the in vitro and in vivo efficacy of T-DXd in primary USC cell lines and xenografts with different HER2 expression. T-DXd-induced cell growth suppression in HER2-overexpressing cell lines in vitro, increased early and late apoptosis as assessed by annexin and propidium iodide staining, and, similarly to trastuzumab, T-DXd-induced significant antibody-dependent cellular cytotoxicity in the presence of peripheral blood lymphocytes. While negligible activity was detected against USC cell lines with low HER2 expression, T-DXd demonstrated significant bystander killing against USC tumors with low/negligible HER2 when such cells were admixed with HER2 3+ tumor cells in vitro. T-DXd showed tumor growth suppression in in vivo USC PDX models that overexpress HER2 at 3+ levels, prolonging survival when compared with controls, with minimal toxicity. Future clinical trials are warranted in patients with USC failing trastuzumab treatment.

Gene expression of non-homologous end-joining pathways in the prognosis of ovarian cancer

Ovarian cancer is the deadliest gynecologic malignancy in women, with a 46% five-year overall survival rate. The objective of the study was to investigate the effects of non-homologous end-joining (NHEJ) genes on clinical outcomes of ovarian cancer patients. To determine if these genes act as prognostic biomarkers of mortality and disease progression, the expression profiles of 48 NHEJ-associated genes were analyzed using an array of statistical and machine learning techniques: logistic regression models, decision trees, naive-Bayes, two sample t-tests, support vector machines, hierarchical clustering, principal component analysis, and neural networks. In this process, the correlation of genes with patient survival and disease progression and recurrence was noted. Also, multiple features from the gene set were found to have significant predictive capabilities. APTX, BRCA1, PAXX, LIG1, and TP53 were identified as most important out of all the candidate genes for predicting clinical outcomes of ovarian cancer patients.

Transforming Growth Factor Beta and Epithelial to Mesenchymal Transition Alter Homologous Recombination Repair Gene Expression and Sensitize BRCA Wild-Type Ovarian Cancer Cells to Olaparib

Epithelial ovarian cancer (EOC) remains the most lethal gynecologic malignancy, largely due to metastasis and drug resistant recurrences. Fifteen percent of ovarian tumors carry mutations in BRCA1 or BRCA2, rendering them vulnerable to treatment with PARP inhibitors such as olaparib. Recent studies have shown that TGFβ can induce "BRCAness" in BRCA wild-type cancer cells. Given that TGFβ is a known driver of epithelial to mesenchymal transition (EMT), and the connection between EMT and metastatic spread in EOC and other cancers, we asked if TGFβ and EMT alter the susceptibility of EOC to PARP inhibition. Epithelial EOC cells were transiently treated with soluble TGFβ, and their clonogenic potential, expression, and function of EMT and DNA repair genes, and response to PARP inhibitors compared with untreated controls. A second epithelial cell line was compared to its mesenchymal derivative for EMT and DNA repair gene expression and drug responses. We found that TGFβ and EMT resulted in the downregulation of genes responsible for homologous recombination (HR) and sensitized cells to olaparib. HR efficiency was reduced in a dose-dependent manner. Furthermore, mesenchymal cells displayed sensitivity to olaparib, cisplatin, and the DNA-PK inhibitor Nu-7441. Therefore, the treatment of disseminated, mesenchymal tumors may represent an opportunity to expand the clinical utility of PARP inhibitors and similar agents.

Vesical clear cell adenocarcinoma of Müllerian origin treated conservatively with partial cystectomy

A 71-year-old woman presented with an intravesical bladder mass found to be a clear cell adenocarcinoma of Müllerian origin with positive PAX-8 staining after transurethral resection. Partial cystectomy along with total hysterectomy were performed, and final pathology revealed no residual tumour and extensive endometriosis. She declined adjuvant therapy and was dispositioned to surveillance.

Financial toxicity in patients with gynecologic malignancies: a cross sectional study

OBJECTIVE

To evaluate financial toxicity and assess its risk factors among patients with gynecologic cancers.

METHODS

This is a cross sectional study that included 2 survey tools, as well as patient demographics, disease characteristics, and treatment regimen. Financial toxicity is measured by validated Comprehensive Score for Financial Toxicity (COST) tool. Participants were also asked to complete a 55-question-survey on attitudes and perspectives surrounding cost of care. Descriptive statistics was used to report patient demographics. Spearman's rank correlation was calculated to assess the relation between financial toxicity and patient/disease related variables. Graphpad Prism Software Version 8.0 was used for analyses.

RESULTS

A total of 50 patients with various gynecologic malignancies were enrolled. Median COST score was 20.5 (range, 1-33). Sixty-five percent of the patients reported being in debt due to their cancer care and 4% filed bankruptcy. Correlation analysis showed that COST score was correlated with age (r=-0.3, p=0.028), malignancy type (r=0.3, p=0.039) and income (r=0.3, p=0.047). Ovarian cancer patients had significantly less financial toxicity (median COST score=23) when compared to patients with other gynecologic malignancies (median COST score=17, p=0.043). When scores were dichotomized into low (score ≥22) and high toxicity (score <22), 58% (29/50) of the patients were noted to have high financial toxicity. Enrollment to a clinical trial did not significantly alleviate financial burden.

CONCLUSION

Financial toxicity is a significant burden even among highly insured gynecologic oncology patients. Age, malignancy type and income were correlated with high financial burden.

In silico screening identifies a novel small molecule inhibitor that counteracts PARP inhibitor resistance in ovarian cancer

Poly ADP-ribose polymerase (PARP) inhibitors are promising targeted therapy for epithelial ovarian cancer (EOC) with BRCA mutations or defective homologous recombination (HR) repair. However, reversion of BRCA mutation and restoration of HR repair in EOC lead to PARP inhibitor resistance and reduced clinical efficacy of PARP inhibitors. We have previously shown that triapine, a small molecule inhibitor of ribonucleotide reductase (RNR), impaired HR repair and sensitized HR repair-proficient EOC to PARP inhibitors. In this study, we performed in silico screening of small molecule libraries to identify novel compounds that bind to the triapine-binding pocket on the R2 subunit of RNR and inhibit RNR in EOC cells. Following experimental validation of selected top-ranking in silico hits for inhibition of dNTP and DNA synthesis, we identified, DB4, a putative RNR pocket-binding inhibitor markedly abrogated HR repair and sensitized BRCA-wild-type EOC cells to the PARP inhibitor olaparib. Furthermore, we demonstrated that the combination of DB4 and olaparib deterred the progression of BRCA-wild type EOC xenografts and significantly prolonged the survival time of tumor-bearing mice. Herein we report the discovery of a putative small molecule inhibitor of RNR and HR repair for combination with PARP inhibitors to treat PARP inhibitor-resistant and HR repair-proficient EOC.

Flow Cytometric Analyses of p53-Mediated Cell Cycle Arrest and Apoptosis in Cancer Cells

Phenotypic analysis of the effects of a gene of interest may be limited because stable expression of some genes leads to adverse consequences in cell survival, such as disturbance of cell cycle progression, senescence, autophagy, and programmed cell death. One of the best examples is tumor suppressor p53. p53 functions as a tumor suppressor by inducing cell cycle arrest and apoptosis in response to genotoxic and environmental insults. The choice and timing of either pathways induced by p53 depend on cellular context, cell types, and the degree of cellular/genomic damage (For review, see (Chen J, Cold Spring Harb Perspect Med 6:a026104, 2016)). The uncertainty makes the studies on the long-term effects of p53 in cells challenging. This chapter describes a method of flow cytometric analysis of ectopic expression of p53 to better quantify cell cycle distribution and apoptosis in cells treated with DNA damaging agents. The method can be easily adapted to other genes of interest to study their contributions to the fate of variety of cell types in response to endogenous or exogenous stresses.

Prescribed medical cannabis in women with gynecologic malignancies: A single-institution survey-based study

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Patients with gynecologic malignancies perceive medical cannabis relieves multiple cancer-related symptoms.

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Medical cannabis is well-tolerated and perceived to have a favorable side effect profile.

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Patients using medical cannabis for pain control report an associated reduction in opioid use.

Research within a gynecologic oncology population has lagged behind the uptake in use of medical cannabis for symptom control. This study seeks to evaluate patient experience with prescribed medical cannabis obtained through licensed dispensaries in women with gynecologic malignancies.

A 43-item survey exploring patient experience with medical cannabis was administered to women with gynecologic malignancies who used medical cannabis prescribed by a gynecologic oncologist.

Thirty-six eligible patients were approached for consent, and 31 patients returned completed surveys (86%). Ninety-three percent had advanced or recurrent disease; 74% were receiving chemotherapy or immunotherapy. Eighty-three percent reported medical cannabis provided relief from cancer or treatment-related symptoms including decreased appetite (41%), insomnia (41%), neuropathy (41%), anxiety (35%), nausea (29%), joint pain (29%), bone pain (29%), abdominal pain (25%), and depression (19%). Eighty percent of patients reported medical cannabis worked the same or better than other traditional medications for management of their cancer or treatment-related symptoms, and 83% reported medical cannabis had an equivalent or better side effect profile. Of the subset of patients using medical cannabis for pain, 63% reported a reduction in opioid use.

Patients perceive that medical cannabis was useful for relief of cancer and treatment-related symptoms, suggesting medical cannabis may be a reasonable alternative or adjunct therapy. Medical cannabis was well tolerated and may have the potential to improve neuropathic pain and decrease opioid use.

Opsoclonus-ataxia syndrome and mature ovarian teratoma in an adolescent

•Ovarian teratomas have been implicated in multiple paraneoplastic syndromes.•Opsoclonus-ataxia syndrome is a rare entity that may be secondary to a paraneoplastic, infectious, or idiopathic process.•Opsoclonus-ataxia syndrome may be associated with ovarian teratoma in both children and adults.•Prompt gynecologic involvement for teratoma resection is warranted.

Phase II evaluation of nivolumab in the treatment of persistent or recurrent cervical cancer (NCT02257528/NRG-GY002)

PURPOSE

Patients with persistent/recurrent cervical cancer following platinum-based chemotherapy have limited therapeutic options. The Gynecologic-Oncology-Group conducted a phase II trial to assess efficacy and tolerability of nivolumab, an immune checkpoint inhibitor, in persistent/recurrent cervical carcinoma.

PATIENTS AND METHODS

Key eligibility criteria included persistent/recurrent cervical cancer, failure of prior systemic therapy and ECOG PS 0-1. Nivolumab 3 mg/kg was given IV every 2 wk. until disease progression or intolerable toxicity. Response was assessed every 8 wk. for 6 months and every 12 wk. thereafter. The primary endpoints were objective response as assessed by RECIST 1.1. The study used a 2-stage group sequential design. PD-L1 expression was evaluated in tumor specimens by immunohistochemistry (IHC) using a combined-positive-score (CPS) cutoff of ≥1%.

RESULTS

Of 26 enrolled patients with persistent/recurrent cervical cancer, 25 were evaluable for response/toxicity with a median age of 45. 36% had ECOG PS of 1, and 100% had received one prior systemic chemotherapy regimen. PD-L1 expression (≥1%) was identified in 77.3% of tumor samples. As of 03/05/19, all patients were off study treatment; median follow-up for survival status was 32 months (range, 2-41.5). There were 21 (84%) patients with a treatment-related adverse event (TRAE) and most were grades 1-2. Six (24%) patients had grade 3 TRAEs with 1 discontinuing nivolumab due to hepatic toxicity. No grade 5 TRAEs occurred, and 2 patients had grade 4 TRAEs. One confirmed partial response (4%; 90% CI, 0.4%-22.9%), duration of response 3.8 months. Thirty-six percent of patients had stable disease (SD) (9/25; 90% CI, 20.2%-54.4%); the median duration of SD was 5.7 months (range, 3.5-12.7). Estimated PFS and OS at 6 months were 16% and 78.4%, respectively.

CONCLUSION

Single agent nivolumab exhibited low antitumor activity and an acceptable safety profile in patients with persistent/recurrent cervical cancer previously treated with platinum-based chemotherapy.

Phase II evaluation of copanlisib, a selective inhibitor of Pi3kca, in patients with persistent or recurrent endometrial carcinoma harboring PIK3CA hotspot mutations: An NRG Oncology study (NRG-GY008)

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Endometrial cancer commonly harbors hotspot mutations in the PIK3CA gene.

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NRG-GY008 evaluated the activity of copanlisib, an inhibitor of PIK3CA, in recurrent endometrial cancer patients.

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Copanlisib has an acceptable safety profile but low antitumor activity in endometrial cancer.

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Combinations of copanlisib may be necessary to increase clinical responses in endometrial cancer patients.

Purpose

NRG Oncology conducted a phase II trial to assess the antitumor activity and tolerability of copanlisib, a selective inhibitor of PIK3CA, in persistent or recurrent endometrial carcinoma harboring hotspot PIK3CA mutations.

Patients and methods

Eligible patients had endometrial cancer with endometrioid, serous or mixed histology, a somatic PIK3CA gene mutation, measurable disease, and GOG performance status ≤2. Treatment consisted of IV copanlisib (60 mg weekly, day 1, 8 and 15 of 28-day cycle) until disease progression or prohibitive toxicity. The primary endpoints of the study were objective tumor response as assessed by RECIST 1.1 and to determine the nature and degree of toxicity of copanlisib as assessed by CTCAE version 4. The study used a 2-stage group sequential design.

Results

Eleven patients were enrolled onto stage I of the treatment trial. Five patients had endometrioid, four serous and two had a tumor of mixed histology. The most common PIK3CA mutation was Q546X (n = 3) in exon 9. The most common grade 3 or 4 AE was hyperglycemia. No grade 5 adverse events were reported. No clinical responses were detected. Six patients had a best overall response of stable disease. Of 11 who initiated treatment, 10 progressed on treatment. One patient with stable disease on copanlisib withdrew from treatment secondary to relocation. The median progression-free survival (PFS) was 2.8 months; at 6 months 27% were alive, progression-free. The median overall survival (OS) was 15.2 months. Due to the lack of CR/PR continuation of accrual to the second stage of accrual was not warranted.

Conclusion

Copanlisib is well tolerated but has limited activity as a single agent in this population.

Combination of triapine, olaparib, and cediranib suppresses progression of BRCA-wild type and PARP inhibitor-resistant epithelial ovarian cancer

PARP inhibitors target BRCA mutations and defective homologous recombination repair (HRR) for the treatment of epithelial ovarian cancer (EOC). However, the treatment of HRR-proficient EOC with PARP inhibitors remains challenging. The objective of this study was to determine whether the combination of triapine (ribonucleotide reductase inhibitor), cediranib (vascular endothelial growth factor receptor tyrosine kinase inhibitor), and the PARP inhibitor olaparib synergized against BRCA wild-type and HRR-proficient EOC in xenograft mouse models. In addition, the mechanisms by which cediranib augmented the efficacy of triapine and olaparib were investigated. BRCA-wild type and PARP inhibitor-resistant EOC cell lines were implanted subcutaneously (s.c.) into nude mice or injected intraperitoneally (i.p.) into SCID-Beige mice. Mice were then treated i.p. with olaparib, cediranib, triapine, various double and triple combinations. The volume of s.c tumor in nude mice and the abdominal circumference of SCID-Beige mice were measured to evaluate the effectiveness of the treatment to delay tumor growth and prolong the survival time of mice. In both xenograft mouse models, the combination of triapine, olaparib and cediranib resulted in marked suppression of BRCA-wild type EOC growth and significant prolongation of the survival time of mice, with efficacy greater than any double combinations and single drugs. Furthermore, we identified that cediranib abrogated pro-survival and anti-apoptotic AKT signaling, thereby enhancing the efficacy of triapine and olaparib against BRCA-wild type EOC cells. Taken together, our results demonstrate a proof-of-principle approach and the combination regiment holds promise in treating BRCA-wild type and PARP inhibitor-resistant EOC.

Extended duration of dilator use beyond 1 year may reduce vaginal stenosis after intravaginal high-dose-rate brachytherapy

BACKGROUND

Vaginal dilators (VD) are recommended following vaginal or pelvic radiotherapy for patients with endometrial carcinoma (EC) to prevent vaginal stenosis (VS). The time course of VS is not fully understood and the optimal duration of VD use is unknown.

METHODS

We reviewed 243 stage IA-II EC patients who received adjuvant brachytherapy (BT) at an academic tertiary referral center. Patients were instructed to use their VD three times per week for at least 1-year duration. The primary outcome was development of grade ≥ 1 VS using CTCAEv4 criteria during the follow-up period. The log-rank test and multivariable Cox proportional hazards modeling were used to evaluate the effect of VD use (noncompliance vs. standard compliance [up to 1 year] vs. extended compliance [over 1 year]) on VS.

RESULTS

The median follow-up was 15.2 months over the 5-year study period. At 15 months, the incidence of VS was 38.8% for noncompliant patients, 33.5% for those with standard compliance, and 21.4% for those with extended compliance (median time to grade ≥ 1 VS was 17.5 months, 26.7 months, and not yet reached for these groups, respectively). On multivariable Cox regression analysis, extended compliance remained a significant predictor of reduced VS risk when compared to both noncompliance (HR 0.38, 95% CI 0.18-0.80, p = 0.012) and standard compliance (HR 0.43, 95% CI 0.20-0.89, p = 0.023).

CONCLUSIONS

The risk of VS persists beyond 1 year after BT. Extended VD compliance beyond 1 year may mitigate this risk.

Targeting Cyclin-Dependent Kinases for Treatment of Gynecologic Cancers

Ovarian, uterine/endometrial, and cervical cancers are major gynecologic malignancies estimated to cause nearly 30,000 deaths in 2018 in US. Defective cell cycle regulation is the hallmark of cancers underpinning the development and progression of the disease. Normal cell cycle is driven by the coordinated and sequential rise and fall of cyclin-dependent kinases (CDK) activity. The transition of cell cycle phases is governed by the respective checkpoints that prevent the entry into the next phase until cellular or genetic defects are repaired. Checkpoint activation is achieved by p53- and ATM/ATR-mediated inactivation of CDKs in response to DNA damage. Therefore, an aberrant increase in CDK activity and/or defects in checkpoint activation lead to unrestricted cell cycle phase transition and uncontrolled proliferation that give rise to cancers and perpetuate malignant progression. Given that CDK activity is also required for homologous recombination (HR) repair, pharmacological inhibition of CDKs can be exploited as a synthetic lethal approach to augment the therapeutic efficacy of PARP inhibitors and other DNA damaging modalities for the treatment of gynecologic cancers. Here, we overview the basic of cell cycle and discuss the mechanistic studies that establish the intimate link between CDKs and HR repair. In addition, we present the perspective of preclinical and clinical development in small molecule inhibitors of CDKs and CDK-associated protein targets, as well as their potential use in combination with hormonal therapy, PARP inhibitors, chemotherapy, and radiation to improve treatment outcomes.

MicroRNA signatures discriminate between uterine and ovarian serous carcinomas

Synchronous endometrial and ovarian malignancies occur in 5% of women presenting with endometrial cancer and 10% of patients presenting with ovarian malignancy. When a high-grade serous carcinoma concurrently involves both ovary and endometrium, pathological determination of whether they are synchronous primaries or metastatic tumors from one primary site can be challenging. MicroRNAs (miRNA) are 22-nucleotide noncoding RNAs that are aberrantly expressed in cancer cells and may inherit their cellular lineage characteristics. We explored possible differential miRNA signatures that may separate high-grade ovarian serous carcinoma from primary endometrial serous carcinoma. Forty-seven samples of histologically pure high-grade serous carcinoma of both uterine (16 case) and ovarian primaries (31 cases) were included. Expression of 384 mature miRNAs was analyzed using ABI TaqMan Low-Density Arrays technology. A random forest model was used to identify miRNAs that together could differentiate between uterine and ovarian serous carcinomas. Among 150 miRNAs detectable at various levels in the study cases, a panel of 11-miRNA signatures was identified to significantly discriminate between ovarian and uterine serous carcinoma (P < .05). A nested cross-validated convergent forest plot using 6 of the 11 miRNA signature was eventually established to classify the tumors with 91.5% accuracy. In conclusion, we have characterized a miRNA signature panel in this exploratory study that shows significant discriminatory power in separating primary ovarian high-grade serous carcinoma from its endometrial counterpart.

Exceptional Response to Pembrolizumab in a Metastatic, Chemotherapy/Radiation-Resistant Ovarian Cancer Patient Harboring a PD-L1-Genetic Rearrangement

Purpose: Ovarian carcinoma no longer responsive to surgery and chemotherapy remains an incurable disease. Alternative therapeutic options remain desperately needed.Patients and Methods: We describe a heavily pretreated patient with ovarian cancer with recurrent disease experiencing a remarkable clinical response to treatment with the anti-PD1 immune checkpoint inhibitor pembrolizumab. The clinical, pathological, and genomic characteristics of this exceptional ovarian cancer responder were carefully investigated using immunohistochemistry (IHC), quantitative multiplex fluorescence methods (i.e., automated quantitative analysis, AQUA) and whole-exome sequencing (WES) techniques.Results: The patient harbored a recurrent/metastatic radiation and chemotherapy-resistant high-grade ovarian carcinoma with clear cell features. While progressing on any standard treatment modality, she demonstrated a remarkable complete response to the anti-PD1 immune checkpoint inhibitor pembrolizumab. WES results were notable for the presence a relative low number of mutations (tumor mutation load/Mb = 4.31, total mutations = 164) and a peculiar structural variant disrupting the 3' region of the PD-L1 gene causing aberrant PD-L1 surface expression as confirmed by IHC and AQUA technology. Heavy infiltration of the PD-L1-mutated and PD-L1-overexpressing tumor with T-cell lymphocytes (i.e., CD4⁺/CD8⁺ TIL), CD68⁺ macrophages, and CD20⁺ B cells was detected in the surgical specimen strongly suggesting immune evasion as a key mechanism of tumor growth and survival. Patient's complete clinical responses remain unchanged at the time of the writing of this report with no significant side effects reported to date.Conclusions: Anti-PD1 inhibitors may represent a novel treatment option for recurrent/metastatic human tumors refractory to salvage treatment harboring PD-L1 gene structural variations causing aberrant PD-L1 expression. Clin Cancer Res; 24(14); 3282-91. ©2018 AACRSee related commentary by Lheureux, p. 3233.

pH-dependent general base catalyzed activation rather than isocyanate liberation may explain the superior anticancer efficacy of laromustine compared to related 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine prodrugs

Laromustine (also known as cloretazine, onrigin, VNP40101M, 101M) is a prodrug of 90CE, a short-lived chloroethylating agent with anticancer activity. The short half-life of 90CE necessitates the use of latentiated prodrug forms for in vivo treatments. Alkylaminocarbonyl-based prodrugs such as laromustine exhibit significantly superior in vivo activity in several murine tumor models compared to analogs utilizing acyl, and alkoxycarbonyl latentiating groups. The alkylaminocarbonyl prodrugs possess two exclusive characteristics: (i) They are primarily unmasked by spontaneous base catalyzed elimination; and (ii) they liberate a reactive carbamoylating species. Previous speculations as to the therapeutic superiority of laromustine have focused upon the inhibition of enzymes by carbamoylation. We have investigated the therapeutic interactions of analogs with segregated chloroethylating and carbamoylating activities (singly and in combination) in the in vivo murine L1210 leukemia model. The combined treatment with chloroethylating and carbamoylating prodrugs failed to result in any synergism and produced a reduction in the therapeutic efficacy compared to the chloroethylating prodrug alone. Evidence supporting an alternative explanation for the superior tumor selectivity of laromustine is presented that is centered upon the high pH sensitivity of its base catalyzed activation, and the more alkaline intracellular pH values commonly found within tumor cells.

Abstract 850: The Pi3K/Akt pathway mediates epithelial-mesenchymal transition (EMT) and malignant progression in BRCA-defective epithelial ovarian cancer

Objectives: Despite improvement in therapy, the majority of patients with ovarian cancer relapses and eventually succumbs to the disease. Therefore, there is an urgent need for further understanding the development and progression of ovarian cancer. It is well established that the phosphatidylinositol 3-kinase (Pi3k/Akt) pathway is activated in 70% of ovarian cancers. We have previously shown that in AKT activity is up regulated in BRCA1 and BRCA-2 deficient cancer. Epithelial-mesenchymal transition (EMT), a process by which cells acquire motility and lose their intercellular adhesions, plays an important role in normal development. Cancer cells have been shown to exhibit similar EMT-like process during invasion and metastasis. Recently, the activation of the Pi3k/Akt pathway is emerging as a central feature of EMT. This study aims to investigate whether activation of the Pi3k/Akt pathway is necessary for promoting EMT and malignant progression in BRCA-defective ovarian cancer.

Methods: BRCA2-mutated PEO1 and BRCA2-wild type PEO4 epithelial ovarian cancer cell lines were derived from the same patient at first and second relapse, respectively, following platinum-based chemotherapy. Non-targeted siRNA control (NTC) and BRCA1-knockdown (BRCA1-kd) SKOV3 cell lines were previously established in our laboratory. Western blot analysis and luciferase reporter assay were performed to determine EMT markers (snail, slug, fibronectin) in BRCA defective ovarian cancer cells. Scratch wound assays were conducted to determine the ability of cells to migrate. Clonogenic and apoptosis assays were carried out to determine cell survival in response to various concentrations of carboplatin and olaparib with or without MK-2206, a small molecule inhibitor of AKT.

Results: PEO1 cells exhibited an increase in mesenchymal markers Snail and fibronectin, whereas PEO4 cells exhibited an increase in the epithelial marker E-cadherin. PEO1 cells also exhibited an increase in cell migration compared with PEO4 cells. In the luciferase reporter assay, BRCA2- mutated PEO1 and BRCA-1 Kd SKOV3 cells exhibited lower levels of the epithelial maker, E-cadherin compared to their BRCA-wild type counterparts, PEO4 and SKOV3 NTC, respectively. Treatment with MK-2206 caused increased susceptibility of BRCA1-kd SKOV3 cells to olaparib compared with BRCA1-wild type SKOV3-NTC cells.

Conclusions: BRCA2-mutated PEO1cells manifested an increase in mesenchymal markers and invasive phenotypes. BRCA1-Kd SKOV3 cells manifested a decrease in the epithelial trait, E-cadherin activity. In addition, AKT inhibition heightened susceptibility of BRCA-1Kd SKOV3 cells to DNA damaging agents such as olaparib. These findings suggest that BRCA-defective cells rely on the induction of EMT via activation of AKT to survive DNA damage and develop therapeutic resistance during malignant progression.

Citation Format: Mehida Alexandre, Z Ping Lin, Elena S. Ratner. The Pi3K/Akt pathway mediates epithelial-mesenchymal transition (EMT) and malignant progression in BRCA-defective epithelial ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 850. doi:10.1158/1538-7445.AM2017-850

When alcohol is the answer: Trapping, identifying and quantifying simple alkylating species in aqueous environments

Alkylating agents are a significant class of environmental carcinogens as well as commonly used anticancer therapeutics. Traditional alkylating activity assays have utilized the colorimetric reagent 4-(4-nitrobenzyl)pyridine (4NBP). However, 4NBP based assays have a relatively low sensitivity towards harder, more oxophilic alkylating species and are not well suited for the identification of the trapped alkyl moiety due to adduct instability. Herein we describe a method using water as the trapping agent which permits the trapping of simple alkylating electrophiles with a comparatively wide range of softness/hardness and permits the identification of donated simple alkyl moieties.

Factors Predictive of Improved Survival in Patients With Brain Metastases From Gynecologic Cancer: A Single Institution Retrospective Study of 47 Cases and Review of the Literature

OBJECTIVE

The reported incidence of brain metastasis from epithelial ovarian cancer (EOC), endometrial cancer (EC), and cervical cancer (CC) is exceedingly rare. As the long-term survival for patients with gynecologic cancer increases, there has been a corresponding increase in the number of diagnosed intracranial metastases. We seek to report our experience with managing brain metastatic disease (BMD) in patients with gynecologic cancer.

METHODS

A retrospective review of all patients with EOC, EC, and CC at our institution revealed 47 patients with concurrent BMD between 2000 and 2013. Demographic data, risk factors, treatment modalities, progression-free data, and overall survival data were collected.

RESULTS

Median survival time in patients with brain metastasis from EOC, EC, and CC was 9.0, 4.5, and 3.0 months, respectively. Two-year overall survival rates were 31.6%, 13.6%, and 0%, respectively. Patients received surgery, radiation therapy alone, palliative care, or radiation plus surgery. Radiation combined with surgical resection resulted in a significant hazards ratio of 0.36 (95% confidence interval, 0.15-0.86), compared with radiation alone.

CONCLUSIONS

Our report provides a large single-institution experience of brain metastases from gynecologic cancer. Patients with BMD have poor prognoses; however, treatment with multimodal therapy including surgical resection and radiation may prolong overall survival.

MK-2206 sensitizes BRCA-deficient epithelial ovarian adenocarcinoma to cisplatin and olaparib

BACKGROUND

Platinum resistance is a major obstacle in the treatment of epithelial ovarian cancer (EOC). Activation of the AKT pathway promotes platinum resistance while inhibition of AKT sensitizes chemoresistant cells. Patients with BRCA mutant EOC, and thus a defect in the homologous recombination (HR) repair pathway, demonstrate greater clinical response to platinum and olaparib therapy than patients with BRCA wild-type EOC. MK-2206, an allosteric inhibitor of AKT phosphorylation, sensitizes a variety of cell types to various anticancer agents and is currently undergoing phase II trials as monotherapy for platinum-resistant ovarian, fallopian tube, and peritoneal cancer. This study examines the differential effects of AKT inhibition with cisplatin and olaparib therapy in BRCA1/2-deficient versus wild-type EOC.

METHODS

PEO1, a chemosensitive BRCA2-mutant serous ovarian adenocarcinoma, and PEO4, a reverted BRCA2-proficient line from the same patient after the development of chemotherapeutic resistance, were primarily used for the study. In PEO1, MK-2206 demonstrated moderate to strong synergism with cisplatin and olaparib at all doses, while demonstrating antagonism at all doses in PEO4.

RESULTS

Baseline phospho-AKT activity in untreated cells was upregulated in both BRCA1- and 2-deficient cell lines. MK-2206 prevented cisplatin- and olaparib-induced AKT activation in the BRCA2-deficient PEO1 cells. We propose that BRCA-deficient EOC cells upregulate baseline AKT activity to enhance survival in the absence of HR. Higher AKT activity is also required to withstand cytotoxic agent-induced DNA damage, leading to strong synergism between MK-2206 and cisplatin or olaparib therapy in BRCA-deficient cells.

CONCLUSIONS

MK-2206 shows promise as a chemosensitization agent in BRCA-deficient EOC and merits clinical investigation in this patient population.

Triapine potentiates platinum-based combination therapy by disruption of homologous recombination repair

Background:

Platinum resistance may be attributable to inherent or acquired proficiency in homologous recombination repair (HRR) in epithelial ovarian cancer (EOC). The objective of this study was to evaluate the efficacy of the small molecule inhibitor triapine to disrupt HRR and sensitise BRCA wild-type EOC cells to platinum-based combination therapy in vitro and in vivo.

Methods:

The sensitivity of BRCA wild-type cancer cells to olaparib, cisplatin, carboplatin, doxorubicin, or etoposide in combination with triapine was evaluated by clonogenic survival assays. The effects of triapine on HRR activity in cells were measured with a DR-GFP reporter assay. The ability of triapine to enhance the effects of the carboplatin-doxil combination on EOC tumour growth delay was determined using a xenograft tumour mouse model.

Results:

Platinum resistance is associated with wild-type BRCA status. Triapine inhibits HRR activity and enhances the sensitivity of BRCA wild-type cancer cells to cisplatin, olaparib, and doxorubicin. However, sequential combination of triapine and cisplatin is necessary to achieve synergism. Moreover, triapine potentiates platinum-based combination therapy against BRCA wild-type EOC cells and produces significant delay of EOC tumour growth.

Conclusions:

Triapine promises to augment the clinical efficacy of platinum-based combination regimens for treatment of platinum-resistant EOC with wild-type BRCA and proficient HRR activity.

Cataloging antineoplastic agents according to their effectiveness against platinum-resistant and platinum-sensitive ovarian carcinoma cell lines

Although epithelial ovarian cancers (EOCs) are initially treated with platinum-based chemotherapy, EOCs vary in platinum responsiveness. Cataloging antineoplastic agents according to their effectiveness against platinum-resistant and platinum-sensitive EOC cell lines is valuable for development of therapeutic strategies to avoid platinum inefficacy and to exploit platinum sensitivity. TOV-21G devoid of FANCF expression, OV-90 and SKOV-3 were employed as examples of platinum-sensitive, platinum-intermediate and platinum-resistant cell lines, respectively. Antineoplastic agents examined included mitomycin C, doxorubicin, etoposide, gemcitabine, chlorambucil, paclitaxel, triapine and X-rays. Their effectiveness against cell lines was analyzed by clonogenic assays. Cytotoxic profiles of mitomycin C and carboplatin were similar, with mitomycin C exhibiting greater potency and selectivity against TOV-21G than carboplatin. Cytotoxic profiles of doxorubicin, etoposide and X-rays overlapped with that of carboplatin, while OV-90 overexpressing Rad51 was more resistant to chlorambucil than SKOV-3. The efficacy of paclitaxel and triapine was independent of platinum sensitivity or resistance. Consistent with these cytotoxic profiles, cisplatin/mitomycin C, triapine, and paclitaxel differed in the capacity to induce phosphorylation of H2AX, and produced unique inhibitory patterns of DNA/RNA syntheses in HL-60 human leukemia cells. Paclitaxel and triapine in combination produced additive antitumor effects in M109 murine lung carcinoma. In conclusion, mitomycin C is potentially more effective against Fanconi anemia pathway-deficient EOCs than carboplatin. Doxorubicin and etoposide, because of their overlapping cytotoxic properties with carboplatin, are unlikely to be efficacious against platinum-refractory EOCs. Paclitaxel and triapine are effective regardless of platinum sensitivity status, and promising in combination for both platinum-sensitive and platinum-refractory EOCs.

A simple and inexpensive method to control oxygen concentrations within physiological and neoplastic ranges

Traditional methods for regulating oxygen concentration ([O2]) in in vitro experiments over the range found in normal and tumor tissues require the use of expensive equipment to generate controlled gas atmospheres or the purchase of a range of gas cylinders with certified O2 percentages. Here we describe a simple and inexpensive enzymatic method for generating low, precise steady-state [O2] levels that are stable for several hours. This method is particularly applicable to the in vitro study of some classes of hypoxia-targeted antitumor prodrugs and bioreductively activated agents.

Assessing associations between the AURKA-HMMR-TPX2-TUBG1 functional module and breast cancer risk in BRCA1/2 mutation carriers

While interplay between BRCA1 and AURKA-RHAMM-TPX2-TUBG1 regulates mammary epithelial polarization, common genetic variation in HMMR (gene product RHAMM) may be associated with risk of breast cancer in BRCA1 mutation carriers. Following on these observations, we further assessed the link between the AURKA-HMMR-TPX2-TUBG1 functional module and risk of breast cancer in BRCA1 or BRCA2 mutation carriers. Forty-one single nucleotide polymorphisms (SNPs) were genotyped in 15,252 BRCA1 and 8,211 BRCA2 mutation carriers and subsequently analyzed using a retrospective likelihood approach. The association of HMMR rs299290 with breast cancer risk in BRCA1 mutation carriers was confirmed: per-allele hazard ratio (HR) = 1.10, 95% confidence interval (CI) 1.04-1.15, p = 1.9 x 10(-4) (false discovery rate (FDR)-adjusted p = 0.043). Variation in CSTF1, located next to AURKA, was also found to be associated with breast cancer risk in BRCA2 mutation carriers: rs2426618 per-allele HR = 1.10, 95% CI 1.03-1.16, p = 0.005 (FDR-adjusted p = 0.045). Assessment of pairwise interactions provided suggestions (FDR-adjusted pinteraction values > 0.05) for deviations from the multiplicative model for rs299290 and CSTF1 rs6064391, and rs299290 and TUBG1 rs11649877 in both BRCA1 and BRCA2 mutation carriers. Following these suggestions, the expression of HMMR and AURKA or TUBG1 in sporadic breast tumors was found to potentially interact, influencing patients' survival. Together, the results of this study support the hypothesis of a causative link between altered function of AURKA-HMMR-TPX2-TUBG1 and breast carcinogenesis in BRCA1/2 mutation carriers.

Weekly ixabepilone with or without biweekly bevacizumab in the treatment of recurrent or persistent uterine and ovarian/primary peritoneal/fallopian tube cancers: A retrospective review

OBJECTIVE

To describe the clinical outcome and tolerability of weekly ixabepilone (16-20mg/m(2) days 1, 8, 15 of a 28-day cycle)±biweekly bevacizumab (10mg/kg days 1 and 15) in patients with recurrent/persistent uterine or ovarian/primary peritoneal/fallopian tube cancers.

METHODS

A single-institution retrospective review was performed inclusive of all patients who received ≥2cycles from 01/2010 to 06/2014. Progression-free (PFS) and overall (OS) survival were determined using the Kaplan-Meier method. Toxicities were graded according to CTCAEv4.0. Best response was categorized using RECIST or by CA-125 criteria.

RESULTS

A total of 60 patients (24 uterine and 36 ovarian cancers) were identified. Patients had received a median of 3.5 (range:1-10) prior lines of chemotherapy. Patients completed a mean of 4.7±2.9cycles of ixabepilone; 66.7% (16/24) and 91.7% (33/36) of patients with uterine and ovarian cancers received concurrent bevacizumab. For uterine cancers, objective response rate (ORR) was 41.7% (12.5% complete, 29.2% partial); median duration of response or stabilization was 7months (range:2-30). Median PFS and OS were 5.2 and 9.6months, respectively. PFS and OS were improved in the setting of concurrent bevacizumab (6.5 versus 3.0months, p=0.01, HR 0.2, 95% CI 0.05-0.77; 9.6 versus 4.2months, p=0.02, HR 0.58, 95% CI 0.04-0.74). Similar ORR was observed among ovarian cancers; median PFS/OS were not yet reached. Most toxicities were grade 1/2.

CONCLUSIONS

Weekly ixabepilone with or without biweekly bevacizumab has promising activity and acceptable toxicity in patients with platinum-/taxane-resistant endometrial and ovarian cancers. This combination warrants further prospective study in these populations.

Distinct mechanisms of cell-kill by triapine and its terminally dimethylated derivative Dp44mT due to a loss or gain of activity of their copper(II) complexes

Triapine, currently being evaluated as an antitumor agent in phase II clinical trials, and its terminally dimethylated derivative Dp44mT share the α-pyridyl thiosemicarbazone backbone that functions as ligands for transition metal ions. Yet, Dp44mT is approximately 100-fold more potent than triapine in cytotoxicity assays. The aims of this study were to elucidate the mechanisms underlying their potency disparity and to determine their kinetics of cell-kill in culture to aid in the formulation of their clinical dosing schedules. The addition of Cu(2+) inactivated triapine in a 1:1 stoichiometric fashion, while it potentiated the cytotoxicity of Dp44mT. Clonogenic assays after finite-time drug-exposure revealed that triapine produced cell-kill in two phases, one completed within 20 min that caused limited cell-kill, and the other occurring after 16 h of exposure that produced extensive cell-kill. The ribonucleotide reductase inhibitor triapine at 0.4 μM caused immediate complete arrest of DNA synthesis, whereas Dp44mT at this concentration did not appreciably inhibit DNA synthesis. The inhibition of DNA synthesis by triapine was reversible upon its removal from the medium. Cell death after 16 h exposure to triapine paralleled the appearance of phospho-(γ)H2AX, a marker of DNA double-strand breaks induced by collapse of DNA replication forks after prolonged replication arrest. In contrast to triapine, Dp44mT produced robust cell-kill within 1h in a concentration-dependent manner. The short-term action of both agents was prevented by thiols, indicative of the involvement of reactive oxygen species. The time dependency in the production of cell-kill by triapine should be considered in treatment regimens.

Triapine disrupts CtIP-mediated homologous recombination repair and sensitizes ovarian cancer cells to PARP and topoisomerase inhibitors

PARP inhibitors exploit synthetic lethality to target epithelial ovarian cancer (EOC) with hereditary BRCA mutations and defects in homologous recombination repair (HRR). However, such an approach is limited to a small subset of EOC patients and compromised by restored HRR due to secondary mutations in BRCA genes. Here, it was demonstrated that triapine, a small-molecule inhibitor of ribonucleotide reductase, enhances the sensitivity of BRCA wild-type EOC cells to the PARP inhibitor olaparib and the topoisomerase II inhibitor etoposide. Triapine abolishes olaparib-induced BRCA1 and Rad51 foci, and disrupts the BRCA1 interaction with the Mre11-Rad50-Nbs1 (MRN) complex in BRCA1 wild-type EOC cells. It has been shown that phosphorylation of CtIP (RBBP8) is required for the interaction with BRCA1 and with MRN to promote DNA double-strand break (DSB) resection during S and G(2) phases of the cell cycle. Mechanistic studies within reveal that triapine inhibits cyclin-dependent kinase (CDK) activity and blocks olaparib-induced CtIP phosphorylation through Chk1 activation. Furthermore, triapine abrogates etoposide-induced CtIP phosphorylation and DSB resection as evidenced by marked attenuation of RPA32 phosphorylation. Concurrently, triapine obliterates etoposide-induced BRCA1 foci and sensitizes BRCA1 wild-type EOC cells to etoposide. Using a GFP-based HRR assay, it was determined that triapine suppresses HRR activity induced by an I-SceI-generated DSB. These results suggest that triapine augments the sensitivity of BRCA wild-type EOC cells to drug-induced DSBs by disrupting CtIP-mediated HRR.

IMPLICATIONS

These findings provide a strong rationale for combining triapine with PARP or topoisomerase inhibitors to target HRR-proficient EOC cells.

Abstract 4490: Triapine sensitizes chemoresistant ovarian cancer cells to platinum therapy

Objectives:

Epithelial ovarian cancer (EOC) is the second most common female pelvic reproductive organ cancer in the United States, and carries the highest mortality in this category in the Western world. The progression free survival and overall survival depend greatly on tumor sensitivity to a platinum chemotherapy. Once platinum resistance is encountered, response rates of only 6-30% are achieved. Triapine, a novel small-molecule drug developed in our laboratory, potently inhibits the activity of ribonucleotide reductase involved in the key step of DNA synthesis and replication. Given that triapine caused profound disruption of dNTP levels and S phase progression, we examined the effects of triapine on the repair of replication-associated DSBs and on the sensitivity of platinum resistant EOC to DNA damaging and platinum therapy.

Methods:

Cell sensitivity to varying ratios of treating drug combinations (triapine/6-thio-guanine alone, triapine/6-thioguanine with cisplatin, carboplatin, doxorubicin, or paclitaxel) was carried out by clonogenic survival assays using multiple EOC cells lines (A2780, CP70, CAOV-3, IGROV-1, BG-1, PEO1, PEO4, SKOV-3). Colonies were stained and counted to determine % survival. DNA replication was determined by EdU incorporation into DNA using flow cytometry and confocal microscopy.

Results:

Treatment with triapine leads to synergistic sensitization of BRCA wild-type EOC cells to platinum drugs. The degree of sensitization by triapine is more pronounced toward the lower concentrations of platinum drugs, at which DNA replication is still ongoing. Platinum drugs induce DNA double strand breaks (DSBs) and Rad51 foci in BRCA wild type EOC cells. Triapine attenuates formation of Rad51 foci, a marker of DSB repair, in these cells. For EOC cells that are highly platinum resistant, combination of triapine and 6-thioguanine is required to achieve significant sensitization to platinum drugs.

Conclusions:

Platinum drugs induce replication-associated DSBs and Rad51-dependent repair in BRCA wild-type EOC cells. Triapine inhibits Rad51-dependent repair of DSBs and therefore sensitizes BRCA wild-type EOC cells to platinum drugs. The mechanism by which 6-thioguanine enhances the effects of triapine is currently being investigated. Our findings indicate for the first time that triapine and 6-thioguanine can be used in combination with platinum agents to target BRCA wild-type and platinum-resistant EOC.

Citation Format: Elena S. Ratner, Margaret Whicker, Z. Ping Lin, Alan C. Sartorelli. Triapine sensitizes chemoresistant ovarian cancer cells to platinum therapy. [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 4490. doi:10.1158/1538-7445.AM2013-4490

Expression of O6-Methylguanine-DNA Methyltransferase Examined by Alkyl-Transfer Assays, Methylation-Specific PCR and Western Blots in Tumors and Matched Normal Tissue

The tumor selectivity of alkylating agents that produce guanine O⁶-chloroethyl (laromustine and carmustine) and O⁶-methyl (temozolomide) lesions, depends upon O⁶-methylguanine-DNA methyltransferase (MGMT) activity being lower in tumor than in host tissue. Despite the established role of MGMT as a tumor resistance factor, consensus on how to assess MGMT expression in clinical samples is unsettled. The aim of this study is to examine the relationship between the values derived from distinctive MGMT measurements in 13, 12, 6 and 2 pairs of human tumors and matched normal adjacent tissue from the colon, kidney, lung and liver, respectively, and in human cell lines. The MGMT measurements included (a) alkyl-transfer assays using [benzene-³H]O⁶-benzylguanine as a substrate to assess functional MGMT activity, (b) methylation-specific PCR (MSP) to probe MGMT gene promoter CpG methylations as a measure of gene silencing, and (c) western immunoblots to analyze the MGMT protein. In human cell lines, a strict negative correlation existed between MGMT activity and the extent of promoter methylation. In tissue specimens, by contrast, the correlation between these two variables was low. Moreover, alkyl-transfer assays identified 3 pairs of tumors and normal tissue with tumor-selective reduction in MGMT activity in the absence of promoter methylation. Cell line MGMT migrated as a single band in western analyses, whereas tissue MGMT was heterogeneous around its molecular size and at much higher molecular masses, indicative of multi-layered post-translational modifications. Malignancy is occasionally associated with a mobility shift in MGMT. Contrary to the prevalent expectation that MGMT expression is governed at the level of gene silencing, these data suggest that other mechanisms that can lead to tumor-selective reduction in MGMT activity exist in human tissue.

Sexual function in older women after oophorectomy

OBJECTIVE

To compare the sexual function of older women who had bilateral oophorectomy with that of older women who had retained their ovaries.

METHODS

This cross-sectional study involved analysis of 1,352 women aged 57 to 85 years from the National Social Life, Health, and Aging Project. Women with previous bilateral oophorectomy were compared with women who retained their ovaries. The primary outcome of interest was self-report of sexual ideation, chosen because having thoughts about sexual experiences is not prohibited by either a partner or a woman's own physical limitations.

RESULTS

Three hundred fifty-six (25.8%) women reported previous bilateral oophorectomy. Our analysis achieved 90% power to detect a difference of 10% in sexual ideation. No significant difference in the report of sexual ideation was found between women with previous bilateral oophorectomy and women who retained their ovaries (54.5% and 95% confidence interval [CI] 48.1-61.0 compared with 49.9% and 95% CI 45.3-54.5, P=.230), even after adjusting for current hormone therapy, age, education, and race (adjusted odds ratio 1.32, 95% CI 0.96-1.80).

CONCLUSION

Bilateral oophorectomy may not play a pivotal role in sexual ideation and function among older women.

LEVEL OF EVIDENCE

II.

Abstract 2743: Triapine sensitizes ovarian cancer cells to platinum drugs and PARP inhibitors

Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone) is a ribonucleotide reductase (RNR) inhibitor that is 1000-times more potent than clinically-used hydroxyurea. Consisting primarily of R2 and R1 subunits during the S phase of the cell cycle, RNR catalyzes the rate-limiting step in the production of deoxyribonucleotides (dNTPs) required for DNA synthesis. Triapine chelates iron to form the triapine-Fe complex that quenches the tyrosyl radical at the R2 subunit and leads to enzymatic inactivation. In recent phase I and II trials, treatment of locally advanced cervical cancer with triapine in combination with cisplatin and radiation was well tolerated and produced high durable complete clinical responses in patients. This promising combination therapy may be attributable to the inhibitory effects of triapine on the repair of cisplatin- and radiation-induced DNA damage. However, the exact DNA repair mechanisms modulated by triapine remain poorly understood. In this study, we demonstrate that treatment of ovarian cancer cells with triapine prompts rapid and prolonged depletion of dATP/dNTP pools, which in turn leads to formation of DNA double strand breaks (DSBs) and inhibition of DNA synthesis in S and G2/M phases of the cell cycle. Furthermore, we show that treatment with triapine results in enhanced sensitization of BRCA-proficient (wild-type) ovarian cancer cells to platinum drugs (cisplatin and carboplatin) and the PARP inhibitor olaparib. Both platinum drugs and PARP inhibitors indirectly cause DSBs which require BRCA1- and BRCA2-dependent homologous recombination (HR) to repair. Collectively, these results suggest that triapine acts to abrogate replicative DNA synthesis and post-replication repair, thereby deterring HR repair of DSBs caused by platinum drugs and other DNA damaging modalities. While 70% of ovarian cancer patients initially respond to platinum-based chemotherapy, the majority of these patients will develop recurrent cancer resistant to the platinum drugs. Emergence of platinum-resistant cancer populations may be associated with increasing proficiency of cancer cells to employ HR to repair DNA damage. Given that, our findings provide the rationale for the use of triapine to enhance the efficacy of platinum-based chemotherapy and PARP inhibitors, and potentially eradicate platinum-resistant ovarian cancer.

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 2743. doi:1538-7445.AM2012-2743

A KRAS variant is a biomarker of poor outcome, platinum chemotherapy resistance and a potential target for therapy in ovarian cancer

Germ-line variants in the 3′ untranslated region (3′UTR) of cancer genes disrupting microRNA (miRNA) regulation have recently been associated with cancer risk. A variant in the 3′UTR of the KRAS oncogene, referred to as the KRAS-variant, is associated with both cancer risk and altered tumor biology. Here we test the hypothesis that the KRAS-variant can act as a biomarker of outcome in epithelial ovarian cancer (EOC), and investigate the cause of altered outcome in KRAS-variant positive EOC patients. As this variant appears to be associated with tumor biology, we additionally test the hypothesis that this variant can be directly targeted to impact cell survival.

EOC patients with complete clinical data were genotyped for the KRAS-variant and analyzed for outcome (n=536), response to neoadjuvant chemotherapy (n=125), and platinum resistance (n=306). Outcome was separately analyzed for women with known BRCA mutations (n=79). Gene expression was analyzed on a subset of tumors with available tissue. Cell lines were employed to confirm altered sensitivity to chemotherapy with the KRAS-variant. The KRAS-variant was directly targeted through siRNA/miRNA oligonucleotides in cell lines and survival was measured.

Post-menopausal EOC patients with the KRAS-variant were significantly more likely to die of ovarian cancer by multivariate analysis (HR=1.67, 95% CI=1.09–2.57, p=0.019, n=279). Possibly explaining this finding, EOC patients with the KRAS-variant were significantly more likely to be platinum resistant (OR=3.18, CI=1.31–7.72, p=0.0106, n=291). Additionally, direct targeting of the KRAS-variant led to a significant reduction in EOC cell growth and survival in vitro.

These findings confirm the importance of the KRAS-variant in EOC, and indicate that the KRAS-variant is a biomarker of poor outcome in EOC likely due to platinum resistance. In addition, this work supports the hypothesis that these tumors have continued dependence on such 3′UTR lesions, and that direct targeting may be a viable future treatment approach.

A survey of gynecologic oncologists regarding the end-of-life discussion: a pilot study

OBJECTIVES

To identify the practices and attitudes of gynecologic oncologists regarding the end-of-life discussion.

METHODS

A pilot survey was sent to 1105 members of the Society of Gynecologic Oncologists (SGO). The survey consisted of 20 questions and was sent via the website Survey Monkey.

RESULTS

Response rate was 12.8%. Sixty percent of respondents were male, most ranged between 30 and 60 years of age and more than half performed 5-10 major surgeries per week. More than half of respondents (53.9%) deferred the End of Life discussion until the patient had sustained a major change in functional and/or medical status. Thirty percent initiated it at the first recurrence or progression of disease. Forty three percent of respondents characterized the discussion as an on-going process. Patients' age, social support, health insurance, and co-morbidities had no influence on the discussion, and neither did the tumor's site of origin or grade. More respondents initiated the discussion in advanced stage cancer (57%) and after salvage chemotherapy institution (54%). Forty four percent of respondents reported that "understanding and acceptance" was the initial response by patient when counseled about withdrawal of care. This increased to 86% when the issue was revisited. Confusion or reluctance to discuss the subject were initially reported to be 12% and 19%, respectively, but decreased to 2% and 3%, respectively, when withdrawal of care was subsequently addressed with the patient.

CONCLUSIONS

This pilot survey sheds a light on attitudes and practices about the end-of-life discussion that deserve to be further studied.

MicroRNA signatures differentiate uterine cancer tumor subtypes

OBJECTIVE

Endometrial cancer (EC) is the most common gynecologic malignancy. Type I EC has a favorable prognosis, while type II ECs account for half of all treatment failures. Little knowledge of the biological differences is available to predict EC outcomes besides their pathological distinctions. MicroRNAs (miRNA) are a family of non-translated RNAs important in regulating oncogenic pathways. Mis-expression patterns of miRNAs in EC, as well as differences in miRNA expression patterns between the subtypes of EC, has not been previously evaluated. Our purpose was to identify miRNA profiles of EC subtypes, and to identify miRNAs associated with these subtypes to ultimately understand the different biological behavior between these subtypes.

METHODS

Ninety-five fresh/frozen and paraffin-embedded samples of endometrial type I and II cancer, carcinosarcomas and benign endometrial samples were collected. MiRNA expression profiles were evaluated by microarray analysis. Statistical analysis was performed.

RESULTS

Distinct miRNA signatures in tumor versus normal samples and in endometrioid vs. uterine papillary serous carcinomas exist. Additionally, carcinosarcomas have a unique miRNA signature from either the type I or II epithelial tumors.

CONCLUSIONS

We hypothesize that further understanding the miRNAs that separate these subtypes of EC will lead to biological insights into the different behavior of these tumors.

Sexuality and intimacy after gynecological cancer

Matters of sexuality and intimacy greatly impact quality of life of patients with gynecologic cancers. Vast amount of evidence exists showing that cancer dramatically impacts woman's sexuality, sexual functioning, intimate relationships and sense of self. Sexual functioning can be affected by illness, pain, anxiety, anger, stressful circumstances and medications. There is a growing acknowledgement that these needs are not being appropriately addressed by providers. With improvements in early detection, surgery and adjuvant therapy for gynecologic cancer, long term survival and cure are becoming possible. Quality of life is thus becoming a major issue for patients. Patients suffer from hot flashes, difficulty sleeping, loss of libido and intimacy, all resulting in significant morbidity and loss of quality of life. Using hormone replacement therapy in gynecologic cancer survivors is a topic a great debate. While limited studies are available to date, retrospective cohort reviews show no reported differences in overall or disease-free survival in patients using hormone replacements vs. controls in patients with ovarian cancer, endometrial cancer, cervical, vaginal or vulva cancer. Since safety of using HRT remains controversial and prospective studies are lacking, providers need to be able to provide alternatives to HRT. Centrally acting agents such as antiseizure agent gabapentin and selective serotonine re-uptake inhibitors, such as venlafaxine and fluoxitine have been demonstrated to show effectiveness in treating vasomotor symptoms and are easily tolerated. To address cardiovascular and osteoporosis risks of post-menopausal status, exercise, healthy diet, bisphosphonates, raloxifen and statins have been found to be effective. Psychotherapy plays an essential part in management of these issues. Review of the literature reveals recent trends among health psychologists to utilize psychoeducational interventions that include combined elements of cognitive and behavioral therapy with education and mindfulness training. Intervention studies have found positive effects from this approach, particularly within the areas of arousal, orgasm, satisfaction, overall well-being, and decreased depression. Many of patients' issues are easy to address with either hormonal, non-hormonal or psychotherapy modifications. The essential part of success is the providers appreciation of this serous problem and willingness and comfort in addressing it.

The KRAS-Variant Genetic Test As a Marker of Increased Risk of Ovarian Cancer

Ovarian cancer (OC) is the fifth leading cause of cancer death in women. High mortality rates are due to vague symptoms of early disease, leading to diagnosis at a late stage. Approximately 10% of OCs are considered hereditary. The KRAS-variant is an inherited, germline variant that has been demonstrated to serve as a genetic marker of increased risk of OC. The KRAS-variant is easily tested in a blood or saliva sample, and has been shown to be at a high prevalence in OC patients. This test could serve as an answer to patients with a family history of ovarian and breast cancer without a previously identifiable genetic mutation.

Trabecular bone mineral density in idiopathic scoliosis

The association of idiopathic scoliosis with an osteoporotic state has been indicated previously. The present study compared the trabecular bone mineral densities of 44 adolescent idiopathic scoliotic girls with 44 age-, weight-, sex-, and race-matched controls. Their lumbar spine and femoral neck bone mineral densities were evaluated using dual-photon absorptiometry. Radiographs and scoliotic curve data were also obtained for the experimental group. The scoliotic subjects exhibited significantly lower lumbar and femoral neck bone mineral densities than the control subjects. No effect was found with respect to treatment, degree, or progression of curvature. The results of this study indicate that there is a generalized state of osteoporosis in idiopathic scoliotic girls when compared with matched controls.