Ovarian cancer treatment: The end of empiricism?

CircNUP50 is a novel therapeutic target that promotes cisplatin resistance in ovarian cancer by modulating p53 ubiquitination

BACKGROUND

Most patients with ovarian cancer (OC) treated with platinum-based chemotherapy have a dismal prognosis owing to drug resistance. However, the regulatory mechanisms of circular RNA (circRNA) and p53 ubiquitination are unknown in platinum-resistant OC. We aimed to identify circRNAs associated with platinum-resistant OC to develop a novel treatment strategy.

METHODS

Platinum-resistant circRNAs were screened through circRNA sequencing and validated using quantitative reverse-transcription PCR in OC cells and tissues. The characteristics of circNUP50 were analysed using Sanger sequencing, oligo (dT) primers, ribonuclease R and fluorescence in situ hybridisation assays. Functional experimental studies were performed in vitro and in vivo. The mechanism underlying circNUP50-mediated P53 ubiquitination was investigated through circRNA pull-down analysis and mass spectrometry, luciferase reporters, RNA binding protein immunoprecipitation, immunofluorescence assays, cycloheximide chase assays, and ubiquitination experiments. Finally, a platinum and si-circNUP50 co-delivery nanosystem (Psc@DPP) was constructed to treat platinum-resistant OC in an orthotopic animal model.

RESULTS

We found that circNUP50 contributes to platinum-resistant conditions in OC by promoting cell proliferation, affecting the cell cycle, and reducing apoptosis. The si-circNUP50 mRNA sequencing and circRNA pull-down analysis showed that circNUP50 mediates platinum resistance in OC by binding p53 and UBE2T, accelerating p53 ubiquitination. By contrast, miRNA sequencing and circRNA pull-down experiments indicated that circNUP50 could serve as a sponge for miR-197-3p, thereby upregulating G3BP1 to mediate p53 ubiquitination, promoting OC platinum resistance. Psc@DPP effectively overcame platinum resistance in an OC tumour model and provided a novel idea for treating platinum-resistant OC using si-circNUP50.

CONCLUSIONS

This study reveals a novel molecular mechanism by which circNUP50 mediates platinum resistance in OC by modulating p53 ubiquitination and provides new insights for developing effective therapeutic strategies for platinum resistance in OC.

RAD51/geminin/γH2AX immunohistochemical expression predicts platinum-based chemotherapy response in ovarian high-grade serous carcinoma

OBJECTIVE

The RAD51 assay is a recently developed functional assay for homologous recombination deficiency (HRD) that reflects real-time HRD status. We aimed to identify the applicability and predictive value of RAD51 immunohistochemical expression in pre- and post-neoadjuvant chemotherapy (NAC) samples of ovarian high-grade serous carcinoma (HGSC).

METHODS

We evaluated the immunohistochemical expression of RAD51/geminin/γH2AX in ovarian HGSC before and after NAC.

RESULTS

In pre-NAC tumors (n=51), 74.5% (39/51) showed at least 25% of γH2AX-positive tumor cells, suggesting endogenous DNA damage. The RAD51-high group (41.0%, 16/39) showed significantly worse progression-free survival (PFS) compared to the RAD51-low group (51.3%, 20/39) (p=0.032). In post-NAC tumors (n=50), the RAD51-high group (36.0%, 18/50) showed worse PFS (p=0.013) and tended to present worse overall survival (p=0.067) compared to the RAD51-low group (64.0%, 32/50). RAD51-high cases were more likely to progress than RAD51-low cases at both 6 months and 12 months (p=0.046 and p=0.019, respectively). Of 34 patients with matched pre- and post-NAC RAD51 results, 44% (15/34) of pre-NAC RAD51 results were changed in the post-NAC tissue, and the RAD51 high-to-high group showed the worst PFS, while the low-to-low group showed the best PFS (p=0.031).

CONCLUSION

High RAD51 expression was significantly associated with worse PFS in HGSC, and post-NAC RAD51 status showed higher association than pre-NAC RAD51 status. Moreover, RAD51 status can be evaluated in a significant proportion of treatment-naïve HGSC samples. As RAD51 status dynamically changes, sequential follow-up of RAD51 status might reflect the biological behavior of HGSCs.

Identification of a novel pyridine derivative with inhibitory activity against ovarian cancer progression in vivo and in vitro

Ovarian cancer is the second leading cause of death of female gynecological malignant tumor patients worldwide. Although surgery and chemotherapy have achieved dramatic achievement, the mortality remains high, resulting in the demand for new specific drug discovery. Disrupting ovarian cancer growth via histone deacetylase (HDAC) inhibition is a strategy for cancer therapy or prevention. In this work, we synthesized a novel pyridine derivative named compound H42 and investigated its anti-cancer activity in vivo and in vitro. We found that compound H42 inhibited ovarian cancer cell proliferation with IC50 values of 0.87 μM (SKOV3) and 5.4 μM (A2780). Further studies confirmed that compound H42 induced apoptosis, intracellular ROS production, and DNA damage. Moreover, compound H42 downregulated the expression of histone deacetylase 6 (HDAC6) with a distinct increase in the acetylation of α-tubulin and heat shock protein 90 (HSP90), followed by the degradation of cyclin D1, resulting in cell cycle arrest at the G0/G1 phase. Importantly, ectopic expression of HDAC6 induced deacetylation of HSP90 and α-tubulin, while HDAC6 knockdown upregulated the acetylation of HSP90 and α-tubulin. However, in the nude xenograft mouse study, compound H42 treatment can inhibit ovarian cancer growth without obvious toxicity. These findings indicated that compound H42 inhibited ovarian cancer cell proliferation through inducing cell cycle arrest at the G0/G1 phase via regulating HDAC6-mediated acetylation, suggesting compound H42 could serve as a lead compound for further development of ovarian cancer therapeutic agents.

Ex vivo assessment of cancer drug sensitivity in epithelial ovarian cancer and its association with histopathological type, treatment history and clinical outcome

Epithelial ovarian cancer (EOC) is divided into type I and type II based on histopathological features. Type I is clinically more indolent, but also less sensitive to chemotherapy, compared with type II. The basis for this difference is not fully clarified. The present study investigated the pattern of drug activity in type I and type II EOC for standard cytotoxic drugs and recently introduced tyrosine kinase inhibitors (TKIs), and assessed the association with treatment history and clinical outcome. Isolated EOC tumor cells obtained at surgery were investigated for their sensitivity to seven standard cytotoxic drugs and nine TKIs using a short-term fluorescent microculture cytotoxicity assay (FMCA). Drug activity was compared with respect to EOC subtype, preoperative chemotherapy, cross-resistance and association with progression-free survival (PFS). Out of 128 EOC samples, 120 samples, including 21 type I and 99 type II, were successfully analyzed using FMCA. Patients with EOC type I had a significantly longer PFS time than patients with EOC type II (P=0.01). In line with clinical experience, EOC type I samples were generally more resistant than type II samples to both standard cytotoxic drugs and the TKIs, reaching statistical significance for cisplatin (P=0.03) and dasatinib (P=0.002). A similar pattern was noted in samples from patients treated with chemotherapy prior to surgery compared with treatment-naive samples, reaching statistical significance for fluorouracil, irinotecan, dasatinib and nintedanib (all P<0.05). PFS time gradually shortened with increasing degree of drug resistance. Cross-resistance between drugs was in most cases statistically significant yet moderate in degree (r<0.5). The clinically observed relative drug resistance of EOC type I, as well as in patients previously treated, is at least partly due to mechanisms in the tumor cells. These mechanisms seemingly also encompass kinase inhibitors. Ex vivo assessment of drug activity is suggested to have a role in the optimization of drug therapy in EOC.

Engineering adoptive T cell therapy to co-opt Fas ligand-mediated death signaling in ovarian cancer enhances therapeutic efficacy

Background

In the USA, more than 50% of patients with ovarian cancer die within 5 years of diagnosis, highlighting the need for therapeutic innovations. Mesothelin (MSLN) is a candidate immunotherapy target; it is overexpressed by ovarian tumors and contributes to malignant/invasive phenotypes, making tumor antigen loss disadvantageous. We previously showed that MSLN-specific T cell receptor (TCR)-engineered T cells preferentially accumulate within established tumors, delay tumor growth, and significantly prolong survival in the ID8_VEGF mouse model that replicates many aspects of human disease. However, T cell persistence and antitumor activity were not sustained. We therefore focused on Fas/FasL signaling that can induce activation-induced cell death, an apoptotic mechanism that regulates T cell expansion. Upregulation of FasL by tumor cells and tumor vasculature has been detected in the tumor microenvironment (TME) of human and murine ovarian cancers, can induce apoptosis in infiltrating, Fas (CD95) receptor-expressing lymphocytes, and can protect ovarian cancers from tumor-infiltrating lymphocytes.

Methods

To overcome potential FasL-mediated immune evasion and enhance T cell responses, we generated an immunomodulatory fusion protein (IFP) containing the Fas extracellular binding domain fused to a 4-1BB co-stimulatory domain, rather than the natural death domain. Murine T cells were engineered to express an MSLN-specific TCR (TCR₁₀₄₅), alone or with the IFP, transferred into ID8_VEGF tumor-bearing mice and evaluated for persistence, proliferation, cytokine production and efficacy. Human T cells were similarly engineered to express an MSLN-specific TCR (TCR₅₃₀) alone or with a truncated Fas receptor or a Fas-4-1BB IFP and evaluated for cytokine production and tumor lysis.

Results

Relative to murine T cells expressing only TCR₁₀₄₅, T cells expressing both TCR₁₀₄₅ and a Fas-4-1BB IFP preferentially persisted in the TME of tumor-bearing mice, with improved T cell proliferation and survival. Moreover, TCR₁₀₄₅/IFP⁺ T cells significantly prolonged survival in tumor-bearing mice, compared with TCR₁₀₄₅-only T cells. Human T cells expressing TCR₅₃₀ and a Fas-4-1BB IFP exhibit enhanced functional activity and viability compared with cells with only TCR₅₃₀.

Conclusions

As many ovarian tumors overexpress FasL, an IFP that converts the Fas-mediated death signal into pro-survival and proliferative signals may be used to enhance engineered adoptive T cell therapy for patients.

Effect of Cerenkov Radiation-Induced Photodynamic Therapy with 18F-FDG in an Intraperitoneal Xenograft Mouse Model of Ovarian Cancer

Ovarian cancer (OC) metastases frequently occur through peritoneal dissemination, and they contribute to difficulties in treatment. While photodynamic therapy (PDT) has the potential to treat OC, its use is often limited by tissue penetration depth and tumor selectivity. Herein, we combined Cerenkov radiation (CR) emitted by 18F-FDG accumulated in tumors as an internal light source and several photosensitizer (PS) candidates with matched absorption bands, including Verteporfin (VP), Chlorin e6 (Ce6) and 5'-Aminolevulinic acid (5'-ALA), to evaluate the anti-tumor efficacy. The in vitro effect of CR-induced PDT (CR-PDT) was evaluated using a cell viability assay, and the efficiency of PS was assessed by measuring the singlet oxygen production. An intraperitoneal ES2 OC mouse model was used for in vivo evaluation of CR-PDT. Positron emission tomography (PET) imaging and bioluminescence-based imaging were performed to monitor the biologic uptake of 18F-FDG and the therapeutic effect. The in vitro studies demonstrated Ce6 and VP to be more effective PSs for CR-PDT. Moreover, VP was more efficient in the generation of singlet oxygen and continued for a long time when exposed to fluoro-18 (18F). Combining CR emitted by 18F-FDG and VP treatment not only significantly suppressed tumor growth, but also prolonged median survival times compared to either monotherapy.

Surgery vs. chemotherapy for ovarian cancer recurrence: what is the best treatment option

Nowadays, the best treatment option for ovarian cancer recurrence is often subjective, can vary in the different centers and depend on personal experience. Arbeitsgemeinschaft Gynaekologische Onkologie (AGO)-DESKTOP studies have identified a population of patients who could benefit from secondary surgery. The results of the Gynecologic Oncology Group (GOG)-0213 study were recently published, which showed no advantage in terms of overall survival (OS) in patients with platinum-sensitive recurrent epithelial ovarian undergoing secondary cytoreductive surgery (SCS) compared to chemotherapy alone. Aim of this narrative review is to summarize the best aspects that can make ovarian cancer recurrence patients suitable for SCS. A narrative review analyzing all the literature of the past 30 years has been performed. PubMed, Scopus, Web of Science and Ovid MEDLINE were used for research. All non-English-language articles have been excluded. The following keywords were searched: 'recurrent ovarian cancer', 'secondary surgery', 'secondary cytoreductive surgery', 'platinum-sensitive ovarian cancer', 'platinum-resistant ovarian cancer'. We divided eligible patients for secondary cytoreduction in relation to the following factors: platinum-sensitivity, AGO-score or Tian model, unresectable lesions, surgical generic contraindication, woman's personal choice. The selection of truly suitable patients for surgery seems an essential requirement for the patient's best therapeutic choice. In case of absent post-surgical residual tumor, good performance status, single recurrence, and platinum-sensitive ovarian recurrence, surgery could be performed.

Designer Self-Assembling Peptide Hydrogels to Engineer 3D Cell Microenvironments for Cell Constructs Formation and Precise Oncology Remodeling in Ovarian Cancer

Designer self-assembling peptides form the entangled nanofiber networks in hydrogels by ionic-complementary self-assembly. This type of hydrogel has realistic biological and physiochemical properties to serve as biomimetic extracellular matrix (ECM) for biomedical applications. The advantages and benefits are distinct from natural hydrogels and other synthetic or semisynthetic hydrogels. Designer peptides provide diverse alternatives of main building blocks to form various functional nanostructures. The entangled nanofiber networks permit essential compositional complexity and heterogeneity of engineering cell microenvironments in comparison with other hydrogels, which may reconstruct the tumor microenvironments (TMEs) in 3D cell cultures and tissue-specific modeling in vitro. Either ovarian cancer progression or recurrence and relapse are involved in the multifaceted TMEs in addition to mesothelial cells, fibroblasts, endothelial cells, pericytes, immune cells, adipocytes, and the ECM. Based on the progress in common hydrogel products, this work focuses on the diverse designer self-assembling peptide hydrogels for instructive cell constructs in tissue-specific modeling and the precise oncology remodeling for ovarian cancer, which are issued by several research aspects in a 3D context. The advantages and significance of designer peptide hydrogels are discussed, and some common approaches and coming challenges are also addressed in current complex tumor diseases.

Changes in DNA Damage Response Markers with Treatment in Advanced Ovarian Cancer

Ovarian cancer (OC) is sensitive to upfront chemotherapy, which is likely attributable to defects in DNA damage repair (DDR). Unfortunately, patients relapse and the evolution of DDR competency are poorly described. We examined the expression of proposed effectors in homologous recombination (HR: RAD51, ATM, FANCD2), error-prone non-homologous end-joining (NHEJ: 53BP1), and base excision repair pathways (BER: PAR and PARP1) in a cohort of sequential OC samples obtained at diagnosis, after neoadjuvant chemotherapy (NACT), and/or at relapse from a total of 147 patients. Immunohistochemical (IHC) expression was quantified using the H-score (0-300), where H ≤ 10 defined negativity. Before NACT, a significant number of cases lacked the expression of some effectors: 60%, 60%, and 24% were PAR-, FANCD2-, or RAD51-negative, with a reassuringly similar proportion of negative biomarkers after NACT. In multivariate analysis, there was a poorer progression-free survival (PFS) and overall survival (OS) for cases with competent HR at diagnosis (PRE-NACT 53BP1-/RAD51+, hazard ratio (HR) 3.13, p = 0.009 and HR 2.78, p = 0.024) and after NACT (POST-NACT FANCD2+/RAD51+ HR 1.89, p = 0.05 and HR 2.38, p = 0.02; POST-NACT PARP-1+/RAD51+ HR 1.79, p = 0.038 and HR 2.04, p = 0.034), reflecting proficient DNA repair. Overall, HR-competent tumors appeared to have a dismal prognosis in comparison with tumors utilizing NHEJ, as assessed either at baseline or post-NACT. Accurate knowledge of the HR status during treatment is clinically important for the efficient timing of platinum-based and targeted therapies with poly(ADP-ribose) polymerase inhibitors (PARPi).

Engineered Adoptive T-cell Therapy Prolongs Survival in a Preclinical Model of Advanced-Stage Ovarian Cancer

Adoptive T-cell therapy using high-affinity T-cell receptors (TCR) to target tumor antigens has potential for improving outcomes in high-grade serous ovarian cancer (HGSOC) patients. Ovarian tumors develop a hostile, multicomponent tumor microenvironment containing suppressive cells, inhibitory ligands, and soluble factors that facilitate evasion of antitumor immune responses. Developing and validating an immunocompetent mouse model of metastatic ovarian cancer that shares antigenic and immunosuppressive qualities of human disease would facilitate establishing effective T-cell therapies. We used deep transcriptome profiling and IHC analysis of human HGSOC tumors and disseminated mouse ID8_VEGF tumors to compare immunologic features. We then evaluated the ability of CD8 T cells engineered to express a high-affinity TCR specific for mesothelin, an ovarian cancer antigen, to infiltrate advanced ID8_VEGF murine ovarian tumors and control tumor growth. Human CD8 T cells engineered to target mesothelin were also evaluated for ability to kill HLA-A2⁺ HGSOC lines. IHC and gene-expression profiling revealed striking similarities between tumors of both species, including processing/presentation of a leading candidate target antigen, suppressive immune cell infiltration, and expression of molecules that inhibit T-cell function. Engineered T cells targeting mesothelin infiltrated mouse tumors but became progressively dysfunctional and failed to persist. Treatment with repeated doses of T cells maintained functional activity, significantly prolonging survival of mice harboring late-stage disease at treatment onset. Human CD8 T cells engineered to target mesothelin were tumoricidal for three HGSOC lines. Treatment with engineered T cells may have clinical applicability in patients with advanced-stage HGSOC.

Epithelial ovarian cancer: Evolution of management in the era of precision medicine

Ovarian cancer is the second most common cause of gynecologic cancer death in women around the world. The outcomes are complicated, because the disease is often diagnosed late and composed of several subtypes with distinct biological and molecular properties (even within the same histological subtype), and there is inconsistency in availability of and access to treatment. Upfront treatment largely relies on debulking surgery to no residual disease and platinum-based chemotherapy, with the addition of antiangiogenic agents in patients who have suboptimally debulked and stage IV disease. Major improvement in maintenance therapy has been seen by incorporating inhibitors against poly (ADP-ribose) polymerase (PARP) molecules involved in the DNA damage-repair process, which have been approved in a recurrent setting and recently in a first-line setting among women with BRCA1/BRCA2 mutations. In recognizing the challenges facing the treatment of ovarian cancer, current investigations are enlaced with deep molecular and cellular profiling. To improve survival in this aggressive disease, access to appropriate evidence-based care is requisite. In concert, realizing individualized precision medicine will require prioritizing clinical trials of innovative treatments and refining predictive biomarkers that will enable selection of patients who would benefit from chemotherapy, targeted agents, or immunotherapy. Together, a coordinated and structured approach will accelerate significant clinical and academic advancements in ovarian cancer and meaningfully change the paradigm of care.

Epithelial ovarian cancer

Epithelial ovarian cancer generally presents at an advanced stage and is the most common cause of gynaecological cancer death. Treatment requires expert multidisciplinary care. Population-based screening has been ineffective, but new approaches for early diagnosis and prevention that leverage molecular genomics are in development. Initial therapy includes surgery and adjuvant therapy. Epithelial ovarian cancer is composed of distinct histological subtypes with unique genomic characteristics, which are improving the precision and effectiveness of therapy, allowing discovery of predictors of response such as mutations in breast cancer susceptibility genes BRCA1 and BRCA2, and homologous recombination deficiency for DNA damage response pathway inhibitors or resistance (cyclin E1). Rapidly evolving techniques to measure genomic changes in tumour and blood allow for assessment of sensitivity and emergence of resistance to therapy, and might be accurate indicators of residual disease. Recurrence is usually incurable, and patient symptom control and quality of life are key considerations at this stage. Treatments for recurrence have to be designed from a patient's perspective and incorporate meaningful measures of benefit. Urgent progress is needed to develop evidence and consensus-based treatment guidelines for each subgroup, and requires close international cooperation in conducting clinical trials through academic research groups such as the Gynecologic Cancer Intergroup.

Landscape of genomic alterations in high-grade serous ovarian cancer from exceptional long- and short-term survivors

BACKGROUND

Patients diagnosed with high-grade serous ovarian cancer (HGSOC) who received initial debulking surgery followed by platinum-based chemotherapy can experience highly variable clinical responses. A small percentage of women experience exceptional long-term survival (long term (LT), 10+ years), while others develop primary resistance to therapy and succumb to disease in less than 2 years (short term (ST)). To improve clinical management of HGSOC, there is a need to better characterize clinical and molecular profiles to identify factors that underpin these disparate survival responses.

METHODS

To identify clinical and tumor molecular biomarkers associated with exceptional clinical response or resistance, we conducted an integrated clinical, exome, and transcriptome analysis of 41 primary tumors from LT (n = 20) and ST (n = 21) HGSOC patients.

RESULTS

Younger age at diagnosis, no residual disease post debulking surgery and low CA125 levels following surgery and chemotherapy were clinical characteristics of LT. Tumors from LT survivors had increased somatic mutation burden (median 1.62 vs. 1.22 non-synonymous mutations/Mbp), frequent BRCA1/2 biallelic inactivation through mutation and loss of heterozygosity, and enrichment of activated CD4+, CD8+ T cells, and effector memory CD4+ T cells. Characteristics of ST survival included focal copy number gain of CCNE1, lack of BRCA mutation signature, low homologous recombination deficiency scores, and the presence of ESR1-CCDC170 gene fusion.

CONCLUSIONS

Our findings suggest that exceptional long- or short-term survival is determined by a concert of clinical, molecular, and microenvironment factors.

Landscape of genomic alterations in high-grade serous ovarian cancer from exceptional long- and short-term survivors

Background

Patients diagnosed with high-grade serous ovarian cancer (HGSOC) who received initial debulking surgery followed by platinum-based chemotherapy can experience highly variable clinical responses. A small percentage of women experience exceptional long-term survival (long term (LT), 10+ years), while others develop primary resistance to therapy and succumb to disease in less than 2 years (short term (ST)). To improve clinical management of HGSOC, there is a need to better characterize clinical and molecular profiles to identify factors that underpin these disparate survival responses.

Methods

To identify clinical and tumor molecular biomarkers associated with exceptional clinical response or resistance, we conducted an integrated clinical, exome, and transcriptome analysis of 41 primary tumors from LT (n = 20) and ST (n = 21) HGSOC patients.

Results

Younger age at diagnosis, no residual disease post debulking surgery and low CA125 levels following surgery and chemotherapy were clinical characteristics of LT. Tumors from LT survivors had increased somatic mutation burden (median 1.62 vs. 1.22 non-synonymous mutations/Mbp), frequent BRCA1/2 biallelic inactivation through mutation and loss of heterozygosity, and enrichment of activated CD4+, CD8+ T cells, and effector memory CD4+ T cells. Characteristics of ST survival included focal copy number gain of CCNE1, lack of BRCA mutation signature, low homologous recombination deficiency scores, and the presence of ESR1-CCDC170 gene fusion.

Conclusions

Our findings suggest that exceptional long- or short-term survival is determined by a concert of clinical, molecular, and microenvironment factors.

Electronic supplementary material

The online version of this article (10.1186/s13073-018-0590-x) contains supplementary material, which is available to authorized users.

Landscape of genomic alterations in high-grade serous ovarian cancer from exceptional long- and short-term survivors

BACKGROUND

Patients diagnosed with high-grade serous ovarian cancer (HGSOC) who received initial debulking surgery followed by platinum-based chemotherapy can experience highly variable clinical responses. A small percentage of women experience exceptional long-term survival (long term (LT), 10+ years), while others develop primary resistance to therapy and succumb to disease in less than 2 years (short term (ST)). To improve clinical management of HGSOC, there is a need to better characterize clinical and molecular profiles to identify factors that underpin these disparate survival responses.

METHODS

To identify clinical and tumor molecular biomarkers associated with exceptional clinical response or resistance, we conducted an integrated clinical, exome, and transcriptome analysis of 41 primary tumors from LT (n = 20) and ST (n = 21) HGSOC patients.

RESULTS

Younger age at diagnosis, no residual disease post debulking surgery and low CA125 levels following surgery and chemotherapy were clinical characteristics of LT. Tumors from LT survivors had increased somatic mutation burden (median 1.62 vs. 1.22 non-synonymous mutations/Mbp), frequent BRCA1/2 biallelic inactivation through mutation and loss of heterozygosity, and enrichment of activated CD4+, CD8+ T cells, and effector memory CD4+ T cells. Characteristics of ST survival included focal copy number gain of CCNE1, lack of BRCA mutation signature, low homologous recombination deficiency scores, and the presence of ESR1-CCDC170 gene fusion.

CONCLUSIONS

Our findings suggest that exceptional long- or short-term survival is determined by a concert of clinical, molecular, and microenvironment factors.

Integrin alpha x stimulates cancer angiogenesis through PI3K/Akt signaling-mediated VEGFR2/VEGF-A overexpression in blood vessel endothelial cells

Integrin alpha x (ITGAX), a member of the integrin family, usually serves as a receptor of the extracellular matrix. Recently, accumulating evidence suggests that ITGAX may be involved in angiogenesis in dendritic cells. Herein, we report a direct role of ITGAX in angiogenesis during tumor development. Overexpression of ITGAX in human umbilical vein endothelial cells (HUVECs) enhanced their proliferation, migration, and tube formation and promoted xenograft ovarian tumor angiogenesis and growth. Further study showed that overexpression of ITGAX activated the PI3k/Akt pathway, leading to the enhanced expression of c-Myc, vascular endothelial growth factor-A (VEGF-A), and VEGF receptor 2 (VEGFR2), whereas, the treatment of cells with PI3K inhibitor diminished these effects. Besides, c-Myc was observed to bind to the VEGF-A promoter. By Co-Immunoprecipitation (Co-IP) assay, we manifested the interaction between ITGAX and VEGFR2 or the phosphorylated VEGFR2. Immunostaining of human ovarian cancer specimens suggested that endothelial cells of micro-blood vessels displayed strong expression of VEGF-A, c-Myc, VEGFR2, and the PI3K signaling molecules. Also, overexpression of ITGAX in HUVECs could stimulate the spheroid formation of ovarian cancer cells. Our study uncovered that ITGAX stimulates angiogenesis through the PI3K/Akt signaling-mediated VEGFR2/VEGF-A overexpression during cancer development.

Bevacizumab combined with platinum-taxane chemotherapy as first-line treatment for advanced ovarian cancer: a prospective observational study of safety and efficacy in Japanese patients (JGOG3022 trial)

BACKGROUND

This was the first large-scale prospective observational Japanese study evaluating the safety and efficacy of bevacizumab combined with paclitaxel and carboplatin for newly diagnosed advanced ovarian cancer.

METHODS

Patients were prospectively enrolled in the primary analysis cohort if they had Stage III or IV epithelial ovarian/fallopian tube/primary peritoneal cancer and were scheduled to receive paclitaxel plus carboplatin every 3 weeks in Cycles 1-6 and bevacizumab every 3 weeks in Cycles 2-22. Primary endpoints were bevacizumab-specific adverse events and adverse events ≥ Grade 3. Secondary endpoints were progression-free survival (PFS) and the response rate.

RESULTS

Among 346 patients enrolled, 293 patients formed the primary analysis cohort. Regarding bevacizumab-specific adverse events ≥ grade 3, incidence rates of thromboembolic events (1.4%), gastrointestinal perforation (0.3%), fistula (0.7%), wound dehiscence (0%), and bleeding (0%) were very low. While incidence rates of hypertension (23.2%) and proteinuria (12.6%) were high, all such events were tolerable. No patient with prior bowel resection developed perforation or fistula. Median PFS was 16.3 months (95% CI 14.5-18.9). The response rate was 77.5% (95% CI 67.4-85.7). The response rate was 63.6% in patients with clear cell carcinoma, which tended to be better than previously reported. The median platinum-free interval was 11.5 months, and the platinum-resistant recurrence rate was 24.5%.

CONCLUSIONS

Combining bevacizumab with chemotherapy was tolerable and efficacy was acceptable in Japanese patients with advanced epithelial ovarian cancer. Bevacizumab seems to reduce platinum-resistant recurrence and is promising for clear cell carcinoma.

CD146 mediates an E-cadherin-to-N-cadherin switch during TGF-β signaling-induced epithelial-mesenchymal transition

Cadherin switch is an initiating factor of epithelial-mesenchymal transition (EMT) and is intimately correlated with cancer metastatic potential; however, its underlying mechanisms remain unclear. Here, using a transforming growth factor-β (TGF-β)-induced EMT model, we provide explicit evidence that CD146, with elevated expression and activity in a variety of cancers, is a key factor involved in the cadherin switch. We show that CD146 can be induced by TGF-β signaling. Moreover, CD146 expression is positively correlated with the activation levels of STAT3/Twist and ERK pathways. Transcriptional response of the CD146/STAT3/Twist cascade inhibits E-cadherin expression, whereas the CD146/ERK cascade enhances N-cadherin expression. CD146 overexpression also significantly promotes EMT in both mouse embryonic fibroblasts (MEFs) and ovarian cancer cells. Clinically, ovarian cancer patients with detectable CD146 expression had a significantly lower survival rate than that of patients without CD146 expression. Furthermore, CD146-deficient MEFs exhibited decreased motility as a result of reversion in this cadherin switch, strongly suggesting that targeting CD146 is a potential strategy for cancer treatment. Therefore, CD146-mediated regulation of the E-cadherin-to-N-cadherin switch provides an insight into the general mechanisms of EMT as well as cancer metastasis.

A review of mirvetuximab soravtansine in the treatment of platinum-resistant ovarian cancer

Resistance to platinum-based therapy poses a significant clinical challenge for the management of advanced ovarian cancer, a leading cause of cancer mortality among women. Mirvetuximab soravtansine is a novel antibody–drug conjugate that targets folate receptor-α, a validated molecular target for therapeutic intervention in this disease. Here, we examine mirvetuximab soravtansine's mechanism of action and pharmacology, and review its clinical evaluation in ovarian cancer to date. We focus on the favorable tolerability and encouraging signals of efficacy that have emerged, most notably in patients with platinum-resistant disease. Ongoing Phase III monotherapy and Phase Ib/II combination trials evaluating its activity in the setting of platinum resistance are emphasized, which will help define its role in the evolving landscape of ovarian cancer therapy.

Selenium-enriched polysaccharides from Pyracantha fortuneana (Se-PFPs) inhibit the growth and invasive potential of ovarian cancer cells through inhibiting β-catenin signaling

Polysaccharides from medicinal plants exert antitumor activity in many cancers. Our previous study demonstrated that polysaccharides extracted from the selenium-enriched Pyracantha fortuneana (Se-PFPs) showed antiproliferative effect in breast cancer cell line. This study aimed to investigate the antitumor effect of Se-PFPs in ovarian cancer cells in vitro and in vivo. Se-PFPs could decrease cell viability, induce apoptosis, and inhibit migratory and invasive potentials in HEY and SKOV3 cells. These findings are supported by reduced expression of cyclin D1, Bcl-2 and MMP-9, enhanced cleavage of PARP and caspase-3, elevated activity of caspase-3 and caspase-9, and EMT (epithelial to mesenchymal transition) inhibition (elevated expression of E-cadherin and cytokeratin 19, and reduced expression of N-cadherin, vimentin, ZEB1 and ZEB2). Moreover, Se-PFPs inhibited xenografted tumor growth through inhibiting cell proliferation and inducing cell apoptosis. More importantly, Se-PFPs significantly reduced cytoplasmic β-catenin particularly nuclear β-catenin expression but increased β-catenin phosphorylation in a GSK-3β-dependent mechanism. Furthermore, β-catenin knockdown exerted similar effects on cell proliferation and invasion as seen in Se-PFPs-treated cells, while β-catenin overexpression neutralized the inhibitory effects of Se-PFPs on cell proliferation and invasion. Take together,Se-PFPs exert antitumor activity through inhibiting cell proliferation, migration, invasion and EMT, and inducing cell apoptosis. These effects are achieved by the inhibition of β-catenin signaling. Thus Se-PFPs can be used as potential therapeutic agents in the prevention and treatment of ovarian cancer.

Somatic BRCA1/2 Recovery as a Resistance Mechanism After Exceptional Response to Poly (ADP-ribose) Polymerase Inhibition

Purpose

Durable and long-term responses to the poly (ADP-ribose) polymerase inhibitor olaparib are observed in patients without BRCA1/2 mutations. However, beyond BRCA1/2 mutations, there are no approved biomarkers for olaparib in high-grade serous ovarian cancer (HGSOC). To determine mechanisms of durable response and resistance to olaparib therapy, we performed an analysis of HGSOC tumors from three patients without germline BRCA1/2 mutations who experienced exceptional responses to olaparib.

Patients and Methods

We performed integrated exome, low-pass genome, and RNA sequence analysis of tumors at diagnosis and upon relapse from patients with platinum-sensitive HGSOC recurrence who were treated > 5 years with olaparib therapy as a single agent.

Results

We observed somatic disruption of BRCA1/2 in all three patients at diagnosis, followed by subsequent BRCA recovery upon progression by copy number gain and/or upregulation of the remaining functional allele in two patients. The third patient with ongoing response (> 7 years) had a tumor at diagnosis with biallelic somatic deletion and loss-of-function mutation, thereby lacking a functional allele for recovery of BRCA1 activity and indicating a potential cure.

Conclusion

Olaparib has durable benefit for patients with ovarian cancer beyond germline BRCA1/2 carriers. These data suggest that biallelic loss of BRCA1/2 in cancer cells may be a potential marker of long-term response to poly (ADP-ribose) polymerase inhibition and that restoration of homologous repair function may be a mechanism of disease resistance.

Efficacy of Postoperative Hormone Replacement Therapy on Prognosis of Patients with Serous Ovarian Carcinoma

Background:

Ovarian cancer is the most common cause of gynecological cancer-associated death. Iatrogenic menopause might adversely affect the quality of life and health outcomes in young female cancer survivors. We evaluated whether postoperative hormone replacement therapy (HRT) had a negative influence on the progression-free survival (PFS) of patients with papillary serous ovarian cancer (SOC).

Methods:

We retrospectively reviewed the medical records of patients with papillary SOC, treated from January 1980 to December 2009, who suffered from menopause with or without HRT. Clinical characteristics of patients were compared between the two groups (HRT and non-HRT). Blood samples were collected from all the participants to detect serum cancer antigen (CA) 125. Hazard ratios with 95% confidential intervals for each variable were calculated by univariable and multivariable conditional Logistic regression analyses.

Results:

Among 112 identified patients, 31 were HRT users and 81 were not. The two groups did not significantly differ in median age at diagnosis (t = 0.652, P = 0.513), International Federation of Gynecology and Obstetrics (FIGO) stage (χ² = 0.565, P = 0.754), differentiation (χ² = 1.728, P = 0.422), resection status (χ² = 0.070, P = 0.791), relapse (χ² = 0.109, P = 0.741), chemotherapy course (t = −1.079, P = 0.282), follow-up interval (t = 0.878, P = 0.382), or PFS (t = 0.580, P = 0.562). Median Kupperman score at the onset of HRT was 30.81 and 12.19 after the therapy (t = 3.302, P = 0.001). According to the analysis, the strongest independent variables in predicting PFS were FIGO stage and disease that was not optimally debulked.

Conclusions:

Postoperative HRT is not a prognostic factor for PFS of patients with papillary SOC. However, multicenter studies are needed to verify and extend our findings.

Targeting CD146 in combination with vorinostat for the treatment of ovarian cancer cells

Drug resistance is the predominant cause of mortality in late-stage patients with ovarian cancer. Histone deacetylase inhibitors (HDACis) have emerged as a novel type of second line drug with high specificity for tumor cells, including ovarian cancer cells. However, HDACis usually exhibit relatively low potencies when used as a single agent. The majority of current clinical trials are combination strategies. These strategies are more empirical than mechanism-based applications. Previously, it was reported that the adhesion molecule cluster of differentiation 146 (CD146) is significantly induced in HDACi-treated tumor cells. The present study additionally confirmed that the induction of CD146 is a common phenomenon in vorinostat-treated ovarian cancer cells. AA98, an anti-CD146 monoclonal antibody (mAb), was used to target CD146 function. Synergistic antitumoral effects between AA98 and vorinostat were examined in vitro and in vivo. The potential effect of combined AA98 and vorinostat treatment on the protein kinase B (Akt) pathway was determined by western blotting. The present study found that targeting of CD146 substantially enhanced vorinostat-induced killing via the suppression of activation of Akt pathways in ovarian cancer cells. AA98 in combination with vorinostat significantly inhibited cell proliferation and increased apoptosis. In vivo, AA98 synergized with vorinostat to inhibit tumor growth and prolong survival in ovarian cancer. These data suggest that an undesired induction of CD146 may serve as a protective response to offset the antitumor efficacy of vorinostat. By contrast, targeting CD146 in combination with vorinostat may be exploited as a novel strategy to more effectively kill ovarian cancer cells.

NT1014, a novel biguanide, inhibits ovarian cancer growth in vitro and in vivo

BACKGROUND

NT1014 is a novel biguanide and AMPK activator with a high affinity for the organic cation-specific transporters, OCT1 and OCT3. We sought to determine the anti-tumorigenic effects of NT1014 in human ovarian cancer cell lines as well as in a genetically engineered mouse model of high-grade serous ovarian cancer.

METHODS

The effects of NT1014 and metformin on cell proliferation were assessed by MTT assay using the human ovarian cancer cell lines, SKOV3 and IGROV1, as well as in primary cultures. In addition, the impact of NT1014 on cell cycle progression, apoptosis, cellular stress, adhesion, invasion, glycolysis, and AMPK activation/mTOR pathway inhibition was also explored. The effects of NT1014 treatment in vivo was evaluated using the K18 - gT121^+/-; p53^fl/fl; Brca1^fl/fl (KpB) mouse model of high-grade serous ovarian cancer.

RESULTS

NT1014 significantly inhibited cell proliferation in both ovarian cancer cell lines as well as in primary cultures. In addition, NT1014 activated AMPK, inhibited downstream targets of the mTOR pathway, induced G1 cell cycle arrest/apoptosis/cellular stress, altered glycolysis, and reduced invasion/adhesion. Similar to its anti-tumorigenic effects in vitro, NT1014 decreased ovarian cancer growth in the KpB mouse model of ovarian cancer. NT1014 appeared to be more potent than metformin in both our in vitro and in vivo studies.

CONCLUSIONS

NT1014 inhibited ovarian cancer cell growth in vitro and in vivo, with greater efficacy than the traditional biguanide, metformin. These results support further development of NT1014 as a useful therapeutic approach for the treatment of ovarian cancer.

The Emerging Role of Tyrosine Kinase Inhibitors in Ovarian Cancer Treatment: A Systematic Review

The present systematic review summarizes current evidence regarding the mechanisms of action, the efficacy, and the adverse effects of tyrosine kinase inhibitors (TKIs) in ovarian cancer patients. Phase II and III clinical trials were sought in the PubMed database and in the Clinical Trials.gov registry through September 30, 2015. Seventy-five clinical trials regarding TKIs targeting mainly vascular endothelial growth factor receptor, epidermal growth factor receptor, platelet-derived growth factor receptor, and sarcoma tyrosine kinase (Src) were yielded. The most promising results were noted with cediranib, nintedanib, and pazopanib. However, drawing universal conclusions about the potential integration of TKIs in ovarian cancer therapy remains elusive. Furthermore, emerging challenges and directions for the future research are critically discussed.

Paclitaxel targets VEGF-mediated angiogenesis in ovarian cancer treatment

Ovarian cancer is one of the gynecologic cancers with the highest mortality, wherein vascular endothelial growth factor (VEGF) is involved in regulating tumor vascularization, growth, migration, and invasion. VEGF-mediated angiogenesis in tumors has been targeted in various cancer treatments, and anti-VEGF therapy has been used clinically for treatment of several types of cancer. Paclitaxel is a natural antitumor agent in the standard front-line treatment that has significant efficiency to treat advanced cancers, including ovarian cancer. Although platinum/paclitaxel-based chemotherapy has good response rates, most patients eventually relapse because the disease develops drug resistance. We aim to review the recent advances in paclitaxel treatment of ovarian cancer via antiangiogenesis. Single-agent therapy may be used in selected cases of ovarian cancer. However, to prevent drug resistance, drug combinations should be identified for optimal effectiveness and existing therapies should be improved.

Strong synergy with APR-246 and DNA-damaging drugs in primary cancer cells from patients with TP53 mutant High-Grade Serous ovarian cancer

BACKGROUND

Mutation in the tumor suppressor gene TP53 is an early event in the development of high-grade serous (HGS) ovarian cancer and is identified in more than 96 % of HGS cancer patients. APR-246 (PRIMA-1(MET)) is the first clinical-stage compound that reactivates mutant p53 protein by refolding it to wild type conformation, thus inducing apoptosis. APR-246 has been tested as monotherapy in a Phase I/IIa clinical study in hematological malignancies and prostate cancer with promising results, and a Phase Ib/II study in combination with platinum-based therapy in ovarian cancer is ongoing. In the present study, we investigated the anticancer effects of APR-246 in combination with conventional chemotherapy in primary cancer cells isolated from ascitic fluid from 10 ovarian, fallopian tube, or peritoneal cancer patients, 8 of which had HGS cancer.

METHODS

Cell viability was assessed with fluorometric microculture cytotoxicity assay (FMCA) and Combination Index was calculated using the Additive model. p53 status was determined by Sanger sequencing and single strand conformation analysis, and p53 protein expression by western blotting.

RESULTS

We observed strong synergy with APR-246 and cisplatin in all tumor samples carrying a TP53 missense mutation, while synergistic or additive effects were found in cells with wild type or TP53 nonsense mutations. Strong synergy was also observed with carboplatin or doxorubicin. Moreover, APR-246 sensitized TP53 mutant primary ovarian cancer cells, isolated from a clinically platinum-resistant patient, to cisplatin; the IC50 value of cisplatin decreased 3.6 fold from 6.5 to 1.8 μM in the presence of clinically relevant concentration of APR-246.

CONCLUSION

These results suggest that combination treatment with APR-246 and DNA-damaging drugs could significantly improve the treatment of patients with TP53 mutant HGS cancer, and thus provide strong support for the ongoing clinical study with APR-246 in combination with carboplatin and pegylated liposomal doxorubicin in patients with recurrent HGS cancer.

Strong synergy with APR-246 and DNA-damaging drugs in primary cancer cells from patients with TP53 mutant High-Grade Serous ovarian cancer

BACKGROUND

Mutation in the tumor suppressor gene TP53 is an early event in the development of high-grade serous (HGS) ovarian cancer and is identified in more than 96 % of HGS cancer patients. APR-246 (PRIMA-1(MET)) is the first clinical-stage compound that reactivates mutant p53 protein by refolding it to wild type conformation, thus inducing apoptosis. APR-246 has been tested as monotherapy in a Phase I/IIa clinical study in hematological malignancies and prostate cancer with promising results, and a Phase Ib/II study in combination with platinum-based therapy in ovarian cancer is ongoing. In the present study, we investigated the anticancer effects of APR-246 in combination with conventional chemotherapy in primary cancer cells isolated from ascitic fluid from 10 ovarian, fallopian tube, or peritoneal cancer patients, 8 of which had HGS cancer.

METHODS

Cell viability was assessed with fluorometric microculture cytotoxicity assay (FMCA) and Combination Index was calculated using the Additive model. p53 status was determined by Sanger sequencing and single strand conformation analysis, and p53 protein expression by western blotting.

RESULTS

We observed strong synergy with APR-246 and cisplatin in all tumor samples carrying a TP53 missense mutation, while synergistic or additive effects were found in cells with wild type or TP53 nonsense mutations. Strong synergy was also observed with carboplatin or doxorubicin. Moreover, APR-246 sensitized TP53 mutant primary ovarian cancer cells, isolated from a clinically platinum-resistant patient, to cisplatin; the IC50 value of cisplatin decreased 3.6 fold from 6.5 to 1.8 μM in the presence of clinically relevant concentration of APR-246.

CONCLUSION

These results suggest that combination treatment with APR-246 and DNA-damaging drugs could significantly improve the treatment of patients with TP53 mutant HGS cancer, and thus provide strong support for the ongoing clinical study with APR-246 in combination with carboplatin and pegylated liposomal doxorubicin in patients with recurrent HGS cancer.

Strong synergy with APR-246 and DNA-damaging drugs in primary cancer cells from patients with TP53 mutant High-Grade Serous ovarian cancer

Background

Mutation in the tumor suppressor gene TP53 is an early event in the development of high-grade serous (HGS) ovarian cancer and is identified in more than 96 % of HGS cancer patients. APR-246 (PRIMA-1^MET) is the first clinical-stage compound that reactivates mutant p53 protein by refolding it to wild type conformation, thus inducing apoptosis. APR-246 has been tested as monotherapy in a Phase I/IIa clinical study in hematological malignancies and prostate cancer with promising results, and a Phase Ib/II study in combination with platinum-based therapy in ovarian cancer is ongoing. In the present study, we investigated the anticancer effects of APR-246 in combination with conventional chemotherapy in primary cancer cells isolated from ascitic fluid from 10 ovarian, fallopian tube, or peritoneal cancer patients, 8 of which had HGS cancer.

Methods

Cell viability was assessed with fluorometric microculture cytotoxicity assay (FMCA) and Combination Index was calculated using the Additive model. p53 status was determined by Sanger sequencing and single strand conformation analysis, and p53 protein expression by western blotting.

Results

We observed strong synergy with APR-246 and cisplatin in all tumor samples carrying a TP53 missense mutation, while synergistic or additive effects were found in cells with wild type or TP53 nonsense mutations. Strong synergy was also observed with carboplatin or doxorubicin. Moreover, APR-246 sensitized TP53 mutant primary ovarian cancer cells, isolated from a clinically platinum-resistant patient, to cisplatin; the IC₅₀ value of cisplatin decreased 3.6 fold from 6.5 to 1.8 μM in the presence of clinically relevant concentration of APR-246.

Conclusion

These results suggest that combination treatment with APR-246 and DNA-damaging drugs could significantly improve the treatment of patients with TP53 mutant HGS cancer, and thus provide strong support for the ongoing clinical study with APR-246 in combination with carboplatin and pegylated liposomal doxorubicin in patients with recurrent HGS cancer.

Deregulated miR-296/S100A4 axis promotes tumor invasion by inducing epithelial-mesenchymal transition in human ovarian cancer

S100A4 represents an important member of the S100 family of small calcium-binding proteins. Increased expression of S100A4 has been observed in chronic inflammatory and autoimmune diseases, such as idiopathic inflammatory myopathies. The majority of studies of S100A4 are focused on cancer research; however, the oncogenic roles of S100A4 in epithelial ovarian cancer (EOC) remain largely unexplored. In this study, S100A4 expression is significantly up-regulated in ovarian cancer and associated with the clinical stage of EOC patients. Attenuation of S100A4 expression results in decreased cell mobility and metastatic capacity, whereas overexpression of S100A4 enhanced the invasive ability of EOC cells. Then by an integrated informatics analysis and luciferase reporter assay, we identify that miR-296 is a critical upstream regulator of S100A4. In addition, deregulated miR-296/S100A4 axis facilitates epithelial-mesenchymal transition (EMT) process as demonstrated by altered expression of EMT-related markers. In conclusion, our study reveals that deregulated miR-296/S100A4 promotes tumor progression in EOC, and provides evidence that miR-296/S100A4 axis-related signaling may represent a potential target for EOC therapy.