Weekly administration of temsirolimus for heavily pretreated patients with clear cell carcinoma of the ovary: a report of six cases

COL6A3 Exosomes Promote Tumor Dissemination and Metastasis in Epithelial Ovarian Cancer

Our study explores the role of cancer-derived extracellular exosomes (EXs), particularly focusing on collagen alpha-3 (VI; COL6A3), in facilitating tumor dissemination and metastasis in epithelial ovarian cancer (EOC). We found that COL6A3 is expressed in aggressive ES2 derivatives, SKOV3 overexpressing COL6A3 (SKOV3/COL6A3), and mesenchymal-type ovarian carcinoma stromal progenitor cells (MSC-OCSPCs), as well as their EXs, but not in less aggressive SKOV3 cells or ES2 cells with COL6A3 knockdown (ES2/shCOL6A3). High COL6A3 expression correlates with worse overall survival among EOC patients, as evidenced by TCGA and GEO data analysis. In vitro experiments showed that EXs from MSC-OCSPCs or SKOV3/COL6A3 cells significantly enhance invasion ability in ES2 or SKOV3/COL6A3 cells, respectively (both, p <0.001). In contrast, ES2 cells with ES2/shCOL6A3 EXs exhibited reduced invasion ability (p < 0.001). In vivo, the average disseminated tumor numbers in the peritoneal cavity were significantly greater in mice receiving intraperitoneally injected SKOV3/COL6A3 cells than in SKOV3 cells (p < 0.001). Furthermore, mice intravenously (IV) injected with SKOV3/COL6A3 cells and SKOV3/COL6A3-EXs showed increased lung colonization compared to mice injected with SKOV3 cells and PBS (p = 0.007) or SKOV3/COL6A3 cells and PBS (p = 0.039). Knockdown of COL6A3 or treatment with EX inhibitor GW4869 or rapamycin-abolished COL6A3-EXs may suppress the aggressiveness of EOC.

From clinical management to personalized medicine: novel therapeutic approaches for ovarian clear cell cancer

Ovarian clear-cell cancer is a rare subtype of epithelial ovarian cancer with unique clinical and biological features. Despite optimal cytoreductive surgery and platinum-based chemotherapy being the standard of care, most patients experience drug resistance and a poor prognosis. Therefore, novel therapeutic approaches have been developed, including immune checkpoint blockade, angiogenesis-targeted therapy, ARID1A synthetic lethal interactions, targeting hepatocyte nuclear factor 1β, and ferroptosis. Refining predictive biomarkers can lead to more personalized medicine, identifying patients who would benefit from chemotherapy, targeted therapy, or immunotherapy. Collaboration between academic research groups is crucial for developing prognostic outcomes and conducting clinical trials to advance treatment for ovarian clear-cell cancer. Immediate progress is essential, and research efforts should prioritize the development of more effective therapeutic strategies to benefit all patients.

Phase II study of gemcitabine, cisplatin, and bevacizumab for first recurrent and refractory ovarian clear cell carcinoma Kansai Clinical Oncology Group-G1601

Patients with advanced ovarian clear cell carcinoma (CCC) have a poor prognosis in the absence of an effective standard treatment. Combination therapy with gemcitabine, cisplatin, and bevacizumab (GPBev) is promising for ovarian CCC. Thus, we conducted a multi-institutional, phase II trial in Japan to examine the efficacy and safety of GPBev for CCC. This is the first study on the use of GPBev for CCC. Eighteen patients (median age, 56.5 years) with pathologically confirmed first recurrent or refractory CCC and having evaluable regions, as assessed using RECIST, were recruited between January 2017 and May 2019. Gemcitabine (1000 mg/m2), cisplatin (40 mg/m2), and bevacizumab (10 mg/kg) were administered intravenously on days 1 and 15, every 28 days, for 6-10 cycles, until disease progression or intolerable toxicity. The primary endpoint was overall response rate (ORR). The secondary endpoints included disease control rate (DCR) and adverse events (AEs). Fifteen patients (83.3%) completed 6-10 cycles of treatment; three patients (two with AEs and one with progressive disease) did not. The ORR was 61.1% [complete response (CR) 3 and partial response (PR) 8] and DCR was 88.9% (CR 3, PR 8, and stable disease 5). Grade 3 and 4 hematological AEs were observed in 16.7 and 5.6% of the patients, respectively. Nonhematological AEs of grades 3 and 4 were observed in 27.8 and 5.6% of the patients, respectively. GPBev is a promising therapy for CCC owing to the high ORR and acceptable toxicity for the first recurrence and refractory CCC.

Relevance of ARID1A Mutations in Endometrial Carcinomas

Since the Cancer Genome Atlas (TCGA) project identified four distinct groups based on molecular alterations, mutation analyses have been integrated into the characterization of endometrial carcinomas (ECs). ARID1A seems to be the subunit more involved in the loss of function of the SWI/SNF complex in ECs. The aim of this study is to define the relevance of ARID1A alterations in a cohort of EC, studying the possible associations between DNA mutation (genomic level), RNA expression (transcriptomic level), and protein expression (proteomic level). A total of 50 endometrial carcinomas were characterized for ARID1A mutations (using targeted DNA next-generation sequencing-NGS), ARID1A gene expression (using RNAseq and qRT-PCR), and ARID1A protein expression (using immunohistochemistry-IHC). Moreover, we have investigated if ARID1A mutations may alter the protein structure, using the Protein Data Bank sequence. We found a good correlation between ARID1A mutations and protein immunostaining, even if we did not find statistically significant differences in the ARID1A expression levels. In conclusion, our data demonstrated that the molecular characterization of ARID1A should be associated with IHC analysis, mainly in those cases harboring "novel" ARID1A mutations or in those alterations with "uncertain" pathogenic significance.

A CLEARER VIEW ON OVARIAN CLEAR CELL CARCINOMA

Introduction: Ovarian clear cell carcinoma (OCCC) is a less common subtype accounting for approximately 5% of all epithelial ovarian cancers (EOCs). Clinical experience and research findings confirm the remarkable differences in clinical behavior, molecular alterations and pathogenesis of OCCC. The diagnosis of OCCC is typically set at a younger age, and earlier stage and in a background of endometriosis.Results: Molecularly, OCCCs rarely harbor BRCA1/BRCA2 mutations and have fewer copy number variants (CNVs). The most common molecular changes occur in the SWI/SNF chromatin remodeling complex genes, the PI3K/AKT signaling pathway and the receptor tyrosine kinase (RTK)/Ras signaling pathway.Five-year disease-specific survival of patients with OCCC is worse compared to high grade serous carcinomas (HGSOC). The current treatment options for OCCC are based on studies that included patients with predominantly HGSOC and only a minor proportion of cancers with clear cell histology. In order to improve outcomes for patients with OCCC, research should be specific for this subtype.Discussion: As the available information about the specific characteristics of OCCC is increasing, especially at a molecular level, it should be possible to continuously improve the specific diagnostics and treatment. Since OCCC is so rare, it is essential to collect new evidence at an international level. To avoid extrapolation from EOC trials with possible erroneous conclusions, patients should always be encouraged to participate in specific histological trials and basket trials, while paying extra attention to OCCC-like subtypes.

The effectiveness of monotherapy with PI3K/AKT/mTOR pathway inhibitors in ovarian cancer: A meta-analysis

OBJECTIVE

To determine the clinical benefit of monotherapy with PI3K/AKT/mTOR inhibitors in patients diagnosed with advanced or recurrent ovarian cancer and to investigate the predictive value of current PI3K/AKT/mTOR biomarkers on therapy response.

METHODS

A systematic search was conducted in PubMed, Embase and the Cochrane Library for articles reporting on treatment with PI3K/AKT/mTOR inhibitors in ovarian cancer. The primary endpoint was defined as the clinical benefit rate (CBR), including the proportion of patients with complete (CR) and partial response (PR) and stable disease (SD). Secondary endpoints included the overall response rate (ORR, including CR and PR) and drug-related grade 3 and 4 adverse events.

RESULTS

We included 233 patients from 19 studies and observed a pooled CBR of 32% (95% CI 20-44%) and ORR of 3% (95% CI 0-6%) in advanced or recurrent ovarian cancer patients treated with PI3K/AKT/mTOR inhibitors. Subgroup analysis tended to favor the studies who selected patients based on current PI3K/AKT/mTOR biomarker criteria (e.g. genomic alterations or loss of PTEN protein expression), but the difference in CBR was not statistically significant from studies with unselected populations (respectively, CBR of 42% (95% CI 23-62%) and 27% (95% CI 14-42%), P = 0.217). To better reflect true patient benefit, we excluded SD <6 months as a beneficial outcome which resulted in a pooled CBR of 7% (95% CI 2-13%). The overall proportion of patients with drug-related grade 3 and 4 adverse events was 36%.

CONCLUSIONS

The efficacy of monotherapy with PI3K/AKT/mTOR inhibitors in advanced recurrent ovarian cancer patients is limited to a small subgroup and selection of patients with the use of current biomarkers did not improved the CBR significantly. Given the toxicity profile, we suggest that current treatment with PI3K/AKT/mTOR inhibitors should not be initiated unless in clinical trials. Furthermore, improved biomarkers to measure functional PI3K/AKT/mTOR pathway activity are needed to optimize patient selection.

Cellular Mechanism of Gene Mutations and Potential Therapeutic Targets in Ovarian Cancer

Ovarian cancer is a common and complex malignancy with poor prognostic outcome. Most women with ovarian cancer are diagnosed with advanced stage disease due to a lack of effective detection strategies in the early stage. Traditional treatment with cytoreductive surgery and platinum-based combination chemotherapy has not significantly improved prognosis and 5-year survival rates are still extremely poor. Therefore, novel treatment strategies are needed to improve the treatment of ovarian cancer patients. Recent advances of next generation sequencing technologies have both confirmed previous known mutated genes and discovered novel candidate genes in ovarian cancer. In this review, we illustrate recent advances in identifying ovarian cancer gene mutations, including those of TP53, BRCA1/2, PIK3CA, and KRAS genes. In addition, we discuss advances in targeting therapies for ovarian cancer based on these mutated genes in ovarian cancer. Further, we associate between detection of mutation genes by liquid biopsy and the potential early diagnostic value in ovarian cancer.

Updates of Pathogenesis, Diagnostic and Therapeutic Perspectives for Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is a special pathological type of epithelial ovarian carcinoma (EOC) and has a high prevalence in Asia without specific molecular subtype classification. Endometriosis is a recognized precancerous lesion that carries 3-fold increased risk of OCCC. Ovarian endometrioid carcinoma, which also originates from endometriosis, shares several features with OCCC, including platinum resistance and younger age at diagnosis. Patients with OCCC have about a 2.5 to 4 times greater risk of having a venous thromboembolism (VTE) compared with other EOC, and OCCC tends to metastasize through lymphatic vesicular and peritoneal spread as opposed to hematogenous metastasis. There is only mild elevation of the conventional biomarker CA125. Staging surgery or optimal cytoreduction combined with chemotherapy is a common therapeutic strategy for OCCC. However, platinum resistance commonly portends a poor prognosis, so novel treatments are urgently needed. Targeted therapy and immunotherapy are currently being studied, including PARP, EZH2, and ATR inhibitors combined with the synthetic lethality of ARID1A-dificiency, and MAPK/PI3K/HER2, VEGF/bFGF/PDGF, HNF1β, and PD-1/PD-L1 inhibitors. Advanced stage, suboptimal cytoreduction, platinum resistance, lymph node metastasis, and VTE are major prognostic predictors for OCCC. We focus on update pathogenesis, diagnostic methods and therapeutic approaches to provide future directions for clinical diagnosis and treatment of OCCC.

Translational genomics of ovarian clear cell carcinoma

Ovarian clear cell carcinomas (OCCC) are rare aggressive, chemo-resistant tumours comprising approximately 13% of all epithelial ovarian cancers, which have distinct clinical and molecular features, when compared to other gynaecological malignancies. At present, there are no specific licensed targeted therapies for OCCC, although a number of candidate targets have been identified. This review focuses on recent knowledge underpinning our understanding of the pathogenesis of OCCC including direct and synthetic-lethal therapeutic strategies in particular focussing on ARID1A deficiency. We also discuss current targeted clinical trials and immunotherapeutic approaches.

Current Position of the Molecular Therapeutic Targets for Ovarian Clear Cell Carcinoma: A Literature Review

Ovarian clear cell carcinoma (OCCC) shows low sensitivity to conventional chemotherapy and has a poor prognosis, especially in advanced stages. Therefore, the development of innovative therapeutic strategies and precision medicine for the treatment of OCCC are important. Recently, several new molecular targets have been identified for OCCC, which can be broadly divided into four categories: (a) downstream pathways of receptor tyrosine kinases, (b) anti-oxidative stress molecules, (c) AT-rich interactive domain 1A-related chromatin remodeling errors, and (d) anti-programmed death ligand 1/programmed cell death 1 agents. Several inhibitors have been discovered for these targets, and the suppression of OCCC cells has been demonstrated both in vitro and in vivo. However, no single inhibitor has shown a sufficient effectiveness in clinical pilot studies. This review outlines recent progress regarding the molecular biological characteristics of OCCC to identify future directions for the development of precision medicine and combinatorial therapies to treat OCCC.

Research progress on the PI3K/AKT signaling pathway in gynecological cancer (Review)

The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway is involved in the regulation of multiple cellular physiological processes by activating downstream corresponding effector molecules, which serve an important role in the cell cycle, growth and proliferation. This is a common phenomenon; overactivation of the pathway is present in human malignancies and has been implicated in cancer progression, hence one of the important approaches to the treatment of tumors is rational drug design using molecular targets in the PI3K/AKT signaling pathway. In brief, the present review analyzed the effects of the PI3K/AKT signaling pathway on certain gynecological cancer types.

Epithelial ovarian cancer: the molecular genetics of epithelial ovarian cancer

BACKGROUND

Epithelial ovarian cancer (EOC) remains one of the leading causes of cancer-related deaths among women worldwide, despite gains in diagnostics and treatments made over the last three decades. Existing markers of ovarian cancer possess very limited clinical relevance highlighting the emerging need for identification of novel prognostic biomarkers as well as better predictive factors that might allow the stratification of patients who could benefit from a more targeted approach.

PATIENTS AND METHODS

A summary of molecular genetics of EOC.

RESULTS

Large-scale high-throughput genomic technologies appear to be powerful tools for investigations into the genetic abnormalities in ovarian tumors, including studies on dysregulated genes and aberrantly activated signaling pathways. Such technologies can complement well-established clinical histopathology analysis and tumor grading and will hope to result in better, more tailored treatments in the future. Genomic signatures obtained by gene expression profiling of EOC may be able to predict survival outcomes and other important clinical outcomes, such as the success of surgical treatment. Finally, genomic analyses may allow for the identification of novel predictive biomarkers for purposes of treatment planning. These data combined suggest a pathway to progress in the treatment of advanced ovarian cancer and the promise of fulfilling the objective of providing personalized medicine to women with ovarian cancer.

CONCLUSIONS

The understanding of basic molecular events in the tumorigenesis and chemoresistance of EOC together with discovery of potential biomarkers may be greatly enhanced through large-scale genomic studies. In order to maximize the impact of these technologies, however, extensive validation studies are required.

PI3K/AKT/mTOR Pathway in Ovarian Cancer Treatment: Are We on the Right Track?

The high recurrence rate and the low overall survival in ovarian cancer suggest that a more specific therapeutic approach in addition to conventional treatment is required. Translational and clinical research is investigating new molecular targets in order to find an alternative way to affect tumor growth and to minimize the overlap of toxicity of antiblastic agents. Given its implication in many cellular activities including regulation of cell growth, motility, survival, proliferation, protein synthesis, autophagy, transcription, as well as angiogenesis, PI3K/AKT/mTOR is one of the most investigated intracellular signaling pathways. A dis-regulation of this pathway has been shown in several tumors, including ovarian cancer. In this setting, mTor proteins represent a potential target for inhibitors, which could ultimately play a pivotal role in counteracting cellular proliferation. Recently, mTor inhibitors have been approved in the treatment of pancreatic neuroendocrine tumors, mantle cell lymphoma and renal cancer. Clinical trials have assessed the safety of these drugs in ovarian cancer patients. Ongoing phase I and II studies are evaluating the oncologic outcome of mTor inhibitor treatment and its effect in combination with conventional chemotherapy and target agents.

PI3K/AKT/mTOR Pathway in Ovarian Cancer Treatment: Are We on the Right Track?

The high recurrence rate and the low overall survival in ovarian cancer suggest that a more specific therapeutic approach in addition to conventional treatment is required. Translational and clinical research is investigating new molecular targets in order to find an alternative way to affect tumor growth and to minimize the overlap of toxicity of antiblastic agents. Given its implication in many cellular activities including regulation of cell growth, motility, survival, proliferation, protein synthesis, autophagy, transcription, as well as angiogenesis, PI3K/AKT/mTOR is one of the most investigated intracellular signaling pathways. A dis-regulation of this pathway has been shown in several tumors, including ovarian cancer. In this setting, mTor proteins represent a potential target for inhibitors, which could ultimately play a pivotal role in counteracting cellular proliferation. Recently, mTor inhibitors have been approved in the treatment of pancreatic neuroendocrine tumors, mantle cell lymphoma and renal cancer. Clinical trials have assessed the safety of these drugs in ovarian cancer patients. Ongoing phase I and II studies are evaluating the oncologic outcome of mTor inhibitor treatment and its effect in combination with conventional chemotherapy and target agents.

PI3K/AKT/mTOR Pathway in Ovarian Cancer Treatment: Are We on the Right Track?

The high recurrence rate and the low overall survival in ovarian cancer suggest that a more specific therapeutic approach in addition to conventional treatment is required. Translational and clinical research is investigating new molecular targets in order to find an alternative way to affect tumor growth and to minimize the overlap of toxicity of antiblastic agents. Given its implication in many cellular activities including regulation of cell growth, motility, survival, proliferation, protein synthesis, autophagy, transcription, as well as angiogenesis, PI3K/AKT/mTOR is one of the most investigated intracellular signaling pathways. A dis-regulation of this pathway has been shown in several tumors, including ovarian cancer. In this setting, mTor proteins represent a potential target for inhibitors, which could ultimately play a pivotal role in counteracting cellular proliferation. Recently, mTor inhibitors have been approved in the treatment of pancreatic neuroendocrine tumors, mantle cell lymphoma and renal cancer. Clinical trials have assessed the safety of these drugs in ovarian cancer patients. Ongoing phase I and II studies are evaluating the oncologic outcome of mTor inhibitor treatment and its effect in combination with conventional chemotherapy and target agents.

Phase 2 trial of everolimus and letrozole in relapsed estrogen receptor-positive high-grade ovarian cancers

OBJECTIVES

We report the results of a phase 2 clinical trial of the combination of everolimus and letrozole in patients with relapsed estrogen receptor-positive high-grade ovarian cancer. The trial's primary endpoint was the proportion of patients alive and progression-free after 12weeks of therapy with the combination of everolimus and letrozole. A 12-week PFS of 45% or greater was considered a positive result. The feasibility of generating patient-derived xenograft (PDX) models from biopsy specimens was also evaluated.

METHODS

Eligibility criteria included relapsed estrogen receptor-positive ovarian, fallopian tube or primary peritoneal carcinomas with measurable disease, not previously treated with everolimus or AIs. Both platinum-resistant and sensitive tumors were included. Xenografts were created from image-guided tumor biopsies at baseline. Patients received oral everolimus 10mg daily and letrozole 2.5mg daily.

RESULTS

Twenty patients were enrolled, 19 were evaluable. Nine out of 19 were alive, progression-free, and still on treatment at the 12week evaluation time-point (12-week PFS of 47%) with a median PFS of 3.9months (95% CI: 2.8-11.0). The median overall survival was 13.0months. Twelve patients (63%) experienced at least one grade 3 or worse adverse events. PDX tumor engraftment was feasible in the majority of patients (9 out of 17, 52.9%).

CONCLUSIONS

The combination of everolimus and letrozole is associated with a promising 47% 12-week PFS rate in patients with ER-positive relapsed high-grade ovarian cancer with acceptable toxicity. PDX tumor models can be generated from biopsies of ovarian tumors.

A Review of mTOR Pathway Inhibitors in Gynecologic Cancer

The treatment of advanced gynecologic cancers remains palliative in most of cases. Although systemic treatment has entered into the era of targeted drugs the antitumor efficacies of current therapies are still limited. In this context there is a great need for more active treatment and rationally designed targeted therapies. The PI3K/AKT/mTOR is a signaling pathway in mammal cells that coordinates important cell activities. It has a critical function in the survival, growth, and proliferation of malignant cells and was object of important research in the last two decades. The mTOR pathway emerges as an attractive therapeutic target in cancer because it serves as a convergence point for many growth stimuli and, through its downstream substrates, controls cellular processes that contribute to the initiation and maintenance of cancer. Aberrant PI3K-dependent signaling occurs frequently in a wide range of tumor types, including endometrial, cervical, and ovarian cancers. The present study reviewed the available evidence regarding the potential impact of some mTOR pathway inhibitors in the treatment of gynecological cancer. Few advances in medical management have occurred in recent years in the treatment of advanced or recurrent gynecological malignancies, and a poor prognosis remains. Rationally designed molecularly targeted therapy is an emerging and important option in this setting; then more investigation in PI3K/AKT/mTOR pathway-targeted therapies is warranted.

Molecular Profiling of Clear Cell Ovarian Cancers: Identifying Potential Treatment Targets for Clinical Trials

Background

Advanced stage/recurrent clear cell ovarian cancers (CCOCs) are characterized by a low response to chemotherapy and a poor prognosis. There is growing interest in investigating novel/molecular targeted therapies in patients with CCOC in histotype-specific trials. However, CCOCs are not a uniform entity and comprise a number of molecular subtypes and it is unlikely that a single approach to treatment will be appropriate for all patients. The aim of this study was to analyze the results of a multiplatform profiling panel in CCOCs to identify potential therapeutic targets.

Patients and Methods

Tumor profiling was performed on 521 CCOCs. They were grouped into pure (n = 422) and mixed (n = 99) CCOC for analysis. Testing included a combination of DNA sequencing (including next-generation sequencing) using a 46-gene panel, immunohistochemistry, fluorescent or chromogenic in situ hybridization, and RNA fragment analysis.

Results

The most common findings were in the PIK3CA/Akt/mTOR pathway, with 61% of all CCOCs showing a molecular alteration in one of these pathway components. Next-generation sequencing revealed PIK3CA mutations in 50% of pure CCOCs. Significant differences were observed between pure and mixed CCOCs with respect to hormone receptor expression (9% vs 34.7% for ER, 13.45 vs 26.4% for PR), cMET (24.1% vs 11.6%), PD-1 tumor infiltrating lymphocytes (48.1% vs 100%), expression of PD-L1 (7.4% vs 25%), and TOPO1 (41% vs 27.1%) on immunohistochemistry, whereas next-generation sequencing revealed significant differences in mutation frequency in PIK3CA (50% vs 18.5%), TP53 (18.1% vs 57.7%), KRAS (12.4% vs 3.7%), and cMET (1.9% vs 11.1%).

Conclusions

This large study confirms that the PIK3CA/Akt/mTOR pathway is commonly altered in CCOCs, and highlights the significant differences between pure and mixed CCOCs. Clear cell ovarian cancers are molecularly heterogeneous and there are a number of potential therapeutic targets which could be tested in clinical trials.

Chemoresistance and targeted therapies in ovarian and endometrial cancers

Gynecological cancers are known for being very aggressive at their advanced stages. Indeed, the survival rate of both ovarian and endometrial cancers is very low when diagnosed lately and the success rate of current chemotherapy regimens is not very efficient. One of the main reasons for this low success rate is the acquired chemoresistance of these cancers during their progression. The mechanisms responsible for this acquired chemoresistance are numerous, including efflux pumps, repair mechanisms, survival pathways (PI3K/AKT, MAPK, EGFR, mTOR, estrogen signaling) and tumor suppressors (P53 and Par-4). To overcome these resistances, a new type of therapy has emerged named targeted therapy. The principle of targeted therapy is simple, taking advantage of changes acquired in malignant cancer cells (receptors, proteins, mechanisms) by using compounds specifically targeting these, thus limiting their action on healthy cells. Targeted therapies are emerging and many clinical trials targeting these pathways, frequently involved in chemoresistance, have been tested on gynecological cancers. Despite some targets being less efficient than expected as mono-therapies, the combination of compounds seems to be the promising avenue. For instance, we demonstrate using ChIP-seq analysis that estrogen downregulate tumor suppressor Par-4 in hormone-dependent cells by directly binding to its DNA regulatory elements and inhibiting estrogen signaling could reinstate Par-4 apoptosis-inducing abilities. This review will focus on the chemoresistance mechanisms and the clinical trials of targeted therapies associated with these, specifically for endometrial and ovarian cancers.

New Insights into mTOR Signal Pathways in Ovarian-Related Diseases: Polycystic Ovary Syndrome and Ovarian Cancer

mTOR, the mammalian target of rapamycin, is a conserved serine/threonine kinase which belongs to the phosphatidyl-linositol kinase-related kinase (PIKK) family. It has two complexes called mTORC1 and mTORC2. It is well established that mTOR plays important roles in cell growth, proliferation and differentiation. Over-activation of the mTOR pathway is considered to have a relationship with the development of many types of diseases, including polycystic ovary syndrome (PCOS) and ovarian cancer (OC). mTOR pathway inhibitors, such as rapamycin and its derivatives, can directly or indirectly treat or relieve the symptoms of patients suffering from PCOS or OC. Moreover, mTOR inhibitors in combination with other chemical-molecular agents may have extraordinary efficacy. This paper will discuss links between mTOR signaling and PCOS and OC, and explore the mechanisms of mTOR inhibitors in treating these two diseases, with conclusions regarding the most effective therapeutic approaches.

Differential effects of rapalogues, dual kinase inhibitors on human ovarian carcinoma cells in vitro

Ovarian cancer is the second most common gynaecological malignancy and was diagnosed in over 7,000 women in 2011 in the UK. There are currently no reliable biomarkers available for use in a regular screening assay for ovarian cancer and due to characteristic late presentation (78% in stages III and IV) ovarian cancer has a low survival rate (35% after 10 years). The mTOR pathway is a central regulator of growth, proliferation, apoptosis and angiogenesis; providing balance between available resources such as amino acids and growth factors, and stresses such as hypoxia, to control cellular behaviour accordingly. Emerging data links mTOR with the aetiopathogenesis of ovarian cancer. We hypothesised that mTOR inhibitors could play a therapeutic role in ovarian cancer treatment. In this study we began by validating the expression of four main mTOR pathway components, mTOR, DEPTOR, rictor and raptor, at gene and protein level in in vitro models of endometrioid (MDAH-2774) and clear cell (SKOV3) ovarian cancer using qPCR and ImageStream technology. Using a wound healing assay we show that inhibition of the mTOR pathway using rapamycin, rapalogues, resveratrol and NVP BEZ-235 induces a cytostatic and not cytotoxic response up to 18 h in these cell lines. We extended these findings up to 72 h with a proliferation assay and show that the effects of inhibition of the mTOR pathway are primarily mediated by the dephosphorylation of p70S6 kinase. We show that mTOR inhibition does not involve alteration of mTOR pathway components or induce caspase 9 cleavage. Preclinical studies including ovarian tissue of ovarian cancer patients, unaffected controls and patients with unrelated gynaecological conditions show that DEPTOR is reliably upregulated in ovarian cancer.

Molecular pathogenesis of ovarian clear cell carcinoma

Ovarian clear cell carcinoma is a distinct subtype of epithelial ovarian cancer, characterized by an association with endometriosis, glycogen accumulation and resistance to chemotherapy. Key driver events, including ARID1A mutations and HNF1B overexpression, have been recently identified and their functional characterization is ongoing. Additionally, the role of glycogen in promoting the malignant phenotype is coming under scrutiny. Appreciation of the notion that ovarian clear cell carcinoma is essentially an ectopic uterine cancer will hopefully lead to improved animal models of the disease, in turn paving the way for effective treatments.

ARID1A gene mutation in ovarian and endometrial cancers (Review)

The AT-rich interacting domain-containing protein 1A gene (ARID1A) encodes ARID1A, a member of the SWI/SNF chromatin remodeling complex. Mutation of ARID1A induces changes in expression of multiple genes (CDKN1A, SMAD3, MLH1 and PIK3IP1) via chromatin remodeling dysfunction, contributes to carcinogenesis, and has been shown to cause transformation of cells in association with the PI3K/AKT pathway. Information on ARID1A has emerged from comprehensive genome-wide analyses with next-generation sequencers. ARID1A mutations have been found in various types of cancer and occur at high frequency in endometriosis-associated ovarian cancer, including clear cell adenocarcinoma and endometrioid adenocarcinoma, and also occur at endometrial cancer especially in endometrioid adenocarcinoma. It has also been suggested that ARID1A mutation occurs at the early stage of canceration from endometriosis to endometriosis-associated carcinoma in ovarian cancer and also from atypical endo-metrial hyperplasia to endometrioid adenocarcinoma in endometrial cancer. Therefore, development of a screening method that can detect mutations of ARID1A and activation of the PI3K/AKT pathway might enable early diagnosis of endometriosis-associated ovarian cancers and endometrial cancers. Important results may also emerge from a current clinical trial examining a multidrug regimen of temsirolimus, a small molecule inhibitor of the PI3K/AKT pathway, for treatment of advanced ovarian clear cell adenocarcinoma with ARID1A mutation and PI3K/AKT pathway activation. Also administration of sorafenib, a multikinase inhibitor, can inhibit cancer proliferation with PIK3CA mutation and resistance to mTOR inhibitors and GSK126, a molecular-targeted drug can inhibit proliferation of ARID1A-mutated ovarian clear cell adenocarcinoma cells by targeting and inhibiting EZH2. Further studies are needed to determine the mechanism of chromatin remodeling dysregulation initiated by ARID1A mutation, to develop methods for early diagnosis, to investigate new cancer therapy targeting ARID1A, and to examine the involvement of ARID1A mutations in development, survival and progression of cancer cells.

p70 S6 kinase drives ovarian cancer metastasis through multicellular spheroid-peritoneum interaction and P-cadherin/b1 integrin signaling activation

Peritoneal dissemination as a manifestation of ovarian cancer is an adverse prognostic factor associated with poor clinical outcome, and is thus a potentially promising target for improved treatment. Sphere forming cells (multicellular spheroids) present in malignant ascites of patients with ovarian cancer represent a major impediment to effective treatment. p70 S6 kinase (p70^S6K), which is a downstream effector of mammalian target of rapamycin, is frequently hyperactivated in human ovarian cancer. Here, we identified p70^S6K as an important regulator for the seeding and successful colonization of ovarian cancer spheroids on the peritoneum. Furthermore, we provided evidence for the existence of a novel crosstalk between P-cadherin and β1 integrin, which was crucial for the high degree of specificity in cell adhesion. In particular, we demonstrated that the upregulation of mature β1 integrin occurred as a consequence of P-cadherin expression through the induction of the Golgi glycosyltransferase, ST6Gal-I, which mediated β1 integrin hypersialylation. Loss of p70^S6K or targeting the P-cadherin/β1-integrin interplay could significantly attenuate the metastatic spread onto the peritoneum in vivo. These findings establish a new role for p70^S6K in tumor spheroid-mesothelium communication in ovarian cancer and provide a preclinical rationale for targeting p70^S6K as a new avenue for microenvironment-based therapeutic strategy.

Salvage Chemotherapy for Patients With Recurrent or Persistent Ovarian Clear Cell Carcinoma: A Retrospective Study of 164 Cases

The purpose of this study was to evaluate the effects of salvage chemotherapy on recurrent or persistent ovarian clear cell carcinoma (CCC) with the goal of identifying a more rational treatment regimen for this lethal disease.The medical records of patients with CCC were retrospectively reviewed to select patients that were subsequently treated for recurrent or persistent disease.Of the 164 women with recurrent or persistent CCC, 485 chemotherapy courses with 1766 cycles were administered. Overall, the clinical benefit rate (CBR) was 39.4%, and the mean progression-free survival (PFS) was 4.5 months. Grade 3/4 toxicities occurred in 94 courses (19.4%). The CBR for TC was 45.1%, with a PFS of 3.7 months. Compared to that of TC, the CBRs for PC and CC were significantly lower (P = 0.020 and 0.021, respectively). The CBRs and PFS for PAF-C were slightly higher (P = 0.518 and 0.077, respectively), but showed a significantly higher adverse event rate (AER, P = 0.039). The CBR for bevacizumab was 50% with an extraordinarily long PFS (49.8 months). Gemcitabine and oxaliplatin had similar values for CBRs (44.4% and 44.1%) and PFS (2.5 and 3.4 months), respectively. Docetaxel (weekly) exhibited a notably low AER of 2.7%, and topotecan was associated with a relatively long PFS (7.7 months).For cis/carboplatin-pretreated patients, the existing active agents, such as oxaliplatin, gemcitabine, topotecan, and especially bevacizumab, are promising. Docetaxel (weekly) is well tolerated and might offer a particularly viable option for heavily pretreated patients. However, additional research to identify for a continued search for the optimal combination of chemotherapeutics or novel agents is still warranted.

The PI3K/Akt/mTOR pathway in ovarian cancer: therapeutic opportunities and challenges

The phosphatidylinositol 3 kinase (PI3K) pathway is frequently altered in cancer, including ovarian cancer (OC). Unfortunately, despite a sound biological rationale and encouraging activity in preclinical models, trials of first-generation inhibitors of mammalian target of rapamycin (mTOR) in OC have demonstrated negative results. The lack of patient selection as well as resistance to selective mTOR complex-1 (mTORC1) inhibitors could explain the disappointing results thus far. Nonetheless, a number of novel agents are being investigated, including dual mTORC1/mTORC2, Akt, and PI3K inhibitors. Although it is likely that inhibition of the PI3K/Akt/mTOR pathway may have little effect in unselected OC patients, certain histological types, such as clear cell or endometrioid OC with frequent phosphatidylinositol-4,5-biphosphate 3-kinase, catalytic subunit alpha (PIK3CA) and/or phosphatase and tensin homolog (PTEN) alterations, may be particularly suited to this approach. Given the complexity and redundancy of the PI3K signaling network, PI3K pathway inhibition may be most useful in combination with either chemotherapy or other targeted therapies, such as MEK inhibitors, anti-angiogenic therapy, and hormonal therapy, in appropriately selected OC patients. Here, we discuss the relevance of the PI3K pathway in OC and provide an up-to-date review of clinical trials of novel PI3K inhibitors alone or in combination with cytotoxics and novel therapies in OC. In addition, the challenges of drug resistance and predictive biomarkers are addressed.

The PI3K/Akt/mTOR pathway in ovarian cancer: therapeutic opportunities and challenges

The phosphatidylinositol 3 kinase (PI3K) pathway is frequently altered in cancer, including ovarian cancer (OC). Unfortunately, despite a sound biological rationale and encouraging activity in preclinical models, trials of first-generation inhibitors of mammalian target of rapamycin (mTOR) in OC have demonstrated negative results. The lack of patient selection as well as resistance to selective mTOR complex-1 (mTORC1) inhibitors could explain the disappointing results thus far. Nonetheless, a number of novel agents are being investigated, including dual mTORC1/mTORC2, Akt, and PI3K inhibitors. Although it is likely that inhibition of the PI3K/Akt/mTOR pathway may have little effect in unselected OC patients, certain histological types, such as clear cell or endometrioid OC with frequent phosphatidylinositol-4,5-biphosphate 3-kinase, catalytic subunit alpha (PIK3CA) and/or phosphatase and tensin homolog (PTEN) alterations, may be particularly suited to this approach. Given the complexity and redundancy of the PI3K signaling network, PI3K pathway inhibition may be most useful in combination with either chemotherapy or other targeted therapies, such as MEK inhibitors, anti-angiogenic therapy, and hormonal therapy, in appropriately selected OC patients. Here, we discuss the relevance of the PI3K pathway in OC and provide an up-to-date review of clinical trials of novel PI3K inhibitors alone or in combination with cytotoxics and novel therapies in OC. In addition, the challenges of drug resistance and predictive biomarkers are addressed.

Ovarian cancer: genomic analysis

OBJECTIVES

Despite improvements in the management of ovarian cancer patients over the last 30 years, there has been only a minimal improvement in overall survival. While targeted therapeutic approaches for the treatment of cancer have evolved, major challenges in ovarian cancer research persist, including the identification of predictive biomarkers with clinical relevance, so that empirical drug selection can be avoided. In this article, we review published genomic analysis studies including data generated in our laboratory and how they have been incorporated into modern clinical trials in a rational and effective way.

METHODS

Multiple published genomic analysis studies were collected for review and discussion with emphasis on their potential clinical applicability.

RESULTS

Genomic analysis has been shown to be a powerful tool to identify dysregulated genes, aberrantly activated pathways and to uncover uniqueness of subclasses of ovarian tumors. The application of this technology has provided a solid molecular basis for different clinical behaviors associated with tumor histology and grade. Genomic signatures have been obtained to predict clinical end points for patients with cancer, including response rates, progression-free survival, and overall survival. In addition, genomic analysis has provided opportunities to identify biomarkers, which either result in a modification of existing clinical management or to stratification of patients to novel therapeutic approaches designed as clinical trials.

CONCLUSIONS

Genomic analyses have accelerated the identification of relevant biomarkers and extended our understanding of the molecular biology of ovarian cancer. This in turn, will hopefully lead to a paradigm shift from empirical, uniform treatment to a more rational, personalized treatment of ovarian cancers. However, validation of potential biomarkers on both the statistical and biological levels is needed to confirm they are of clinical relevance, in order to increase the likelihood that the desired outcome can be predicted and achieved.

Clear cell carcinoma of ovary and uterus

Clear cell carcinomas of the female genital tract are rare tumours with a fearsome reputation for having poor responses to conventional platinum-based chemotherapy and poor prognosis. However, it is now clear that early-stage ovarian clear cell carcinoma has an excellent prognosis and may not require any adjuvant therapy. In addition, radiotherapy may also have a key role to play in adjuvant management of clear cell tumours. Identification of patients who truly do not need adjuvant chemotherapy is important. The past 3 years has seen a significant improvement in our understanding of clear cell carcinoma biology-in particular, the role of mutations in the chromatin remodelling gene ARID1A as key drivers that are common to clear cell carcinomas of ovarian and endometrial origin. Moreover, gynaecological clear cell carcinomas appear to share many features with renal clear cell tumours, suggesting a common pathogenesis. This raises the possibility of clinical trials that include patients with clear cell tumours from different organs of origin. Dissecting the role of disordered chromatin organisation in clear cell carcinoma pathogenesis is a key priority. Finally, the role of endometriosis and the attendant chronic inflammation are recognised. The inflammatory cytokine interleukin-6 appears to play a key role in clear cell carcinoma biology and is an excellent potential therapeutic target.

Temsirolimus and pegylated liposomal doxorubicin (PLD) combination therapy in breast, endometrial, and ovarian cancer: phase Ib results and prediction of clinical outcome with FDG-PET/CT

Pegylated liposomal doxorubicin (PLD) is active in breast, endometrial, and ovarian cancer. Preclinical data suggest that the combination of PLD with a mammalian target of rapamycin (mTOR) inhibitor has an additive effect. The safety and recommended phase two dose (RPTD) of temsirolimus in combination with PLD were assessed. (18) F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT was performed for early response monitoring. Nineteen patients with advanced breast, endometrial, and ovarian cancer were treated with increasing doses of temsirolimus (10, 15, or 20 mg once weekly) and PLD (30 or 40 mg/m(2) once every 4 weeks). PLD was initiated 2 weeks after start of temsirolimus. FDG-PET/CT was performed at baseline, after 2 and 6 weeks. Standardized uptake values (SUV), metabolic volume, and total lesion glycolysis (TLG, SUV × metabolic volume) were calculated. The RPTD was 15 mg temsirolimus and 40 mg/m(2) PLD. Dose-limiting toxicities (DLT) were thrombocytopenia grade 3 with nose bleeding and skin toxicity grade 3. Most frequent treatment-related toxicities were nausea, fatigue, mucositis, and skin toxicity. Changes in TLG after 2 weeks predicted partial response (PR) after 10 weeks (p = 0.037). A rise in SUV between the second and sixth week predicted progression (PD) (p = 0.034) and was associated with worse progression free survival (PFS) (HR 1.068; p = 0.013). The RPTD was established at 15 mg temsirolimus weekly and PLD 40 mg/m(2) once every 4 weeks and the combination was safe. Early response evaluation with FDG-PET/CT may predict subsequent radiological PR and PD. This trial is registered under number NCT0098263.

Antitumor activity and induction of TP53-dependent apoptosis toward ovarian clear cell adenocarcinoma by the dual PI3K/mTOR inhibitor DS-7423

DS-7423, a novel, small-molecule dual inhibitor of phosphatidylinositol-3-kinase (PI3K) and mammalian target of rapamycin (mTOR), is currently in phase I clinical trials for solid tumors. Although DS-7423 potently inhibits PI3Kα (IC50 = 15.6 nM) and mTOR (IC50 = 34.9 nM), it also inhibits other isoforms of class I PI3K (IC50 values: PI3Kβ = 1,143 nM; PI3Kγ = 249 nM; PI3Kδ = 262 nM). The PI3K/mTOR pathway is frequently activated in ovarian clear cell adenocarcinomas (OCCA) through various mutations that activate PI3K-AKT signaling. Here, we describe the anti-tumor effect of DS-7423 on a panel of nine OCCA cell lines. IC50 values for DS-7423 were <75 nM in all the lines, regardless of the mutational status of PIK3CA. In mouse xenograft models, DS-7423 suppressed the tumor growth of OCCA in a dose-dependent manner. Flow cytometry analysis revealed a decrease in S-phase cell populations in all the cell lines and an increase in sub-G1 cell populations following treatment with DS-7423 in six of the nine OCCA cell lines tested. DS-7423-mediated apoptosis was induced more effectively in the six cell lines without TP53 mutations than in the three cell lines with TP53 mutations. Concomitantly with the decreased phosphorylation level of MDM2 (mouse double minute 2 homolog), the level of phosphorylation of TP53 at Ser46 was increased by DS-7423 in the six cell lines with wild-type TP53, with induction of genes that mediate TP53-dependent apoptosis, including p53AIP1 and PUMA at 39 nM or higher doses. Our data suggest that the dual PI3K/mTOR inhibitor DS-7423 may constitute a promising molecular targeted therapy for OCCA, and that its antitumor effect might be partly obtained by induction of TP53-dependent apoptosis in TP53 wild-type OCCAs.

Effective use of everolimus as salvage chemotherapy for ovarian clear cell carcinoma: a case report

A case study using mammalian target of rapamycin complex 1 in recurrent ovarian clear cell carcinoma (CCC) was recently conducted. We report our experience with a patient suffering from recurrent ovarian CCC who achieved long-term disease control with everolimus administration. The patient was a 53-year-old woman who was diagnosed with recurrent ovarian CCC with dissemination throughout the abdominal cavity. Previously, she had received three chemotherapy regimens, but the disease was progressive and she showed no response to treatment. Therefore, oral everolimus administration (everolimus 10 mg/day on days 1-28, a 28-day period comprised one cycle) was started. She was administered six cycles. The antitumor response was stable disease, and grade 3 anemia was observed. Chemotherapy was then switched to gemcitabine/docetaxel therapy. In the middle of the second cycle, a rapid increase in ascitic fluid and CA125 elevation were observed. Thereafter, the patient received best supportive care and died of the disease. Everolimus may inhibit malignant progression of ovarian CCC.

The potential of sunitinib as a therapy in ovarian cancer

INTRODUCTION

Sunitinib malate (SU11248; Sutent®; Pfizer, Inc., New York) is a multi-kinase inhibitor currently approved for use in advanced renal cell carcinoma (RCC), imatinib-resistant/-intolerant gastrointestinal stromal tumours and progressive, well-differentiated pancreatic neuroendocrine tumours in patients with unresectable, locally advanced or metastatic disease.

AREAS COVERED

This article describes the mechanism of action and of the pharmacokinetics of sunitinib; further, it summarizes Phase I and II trials on the clinical efficacy, tolerability and safety of this agent in the setting of ovarian cancer (OC) treatment.

EXPERT OPINION

On the basis of the current literature, sunitinib has shown modest antitumour activity and acceptable toxicity. Studies investigating the impact of horizontal and vertical combinations should represent a priority of future research. Although clinical Phase II trials on the use of sunitinib in the treatment of OC demonstrated an acceptable profile of AEs, a greater comprehension of the toxicity of this compound is recommended.

A Case of Stage III c Ovarian Clear Cell Carcinoma: The Role for Predictive Biomarkers and Targeted Therapies

Ovarian cancer treatment presently does not reflect molecular differences in histologic subtype. Ovarian clear cell carcinoma (OCCC) exhibits several differences in terms of molecular pathogenesis and tumor behavior from the more common, chemosensitive, serous carcinomas, which makes OCCC a candidate for targeted therapies. A 53-year-old Japanese woman was diagnosed with stage IIIc ovarian clear cell adenocarcinoma with marked chemoresistance to conventional regimens. She demonstrated a partial response to a multikinase inhibitor. The tumor was resistant to PI3K/mTOR pathway inhibitors despite harboring a PIK3CA mutation. The present case suggests a role for targeted therapies in the treatment of OCCC and a need for the identification of biomarkers that will predict response to targeted therapies.

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

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

Clear cell carcinoma of the ovary: is there a role of histology-specific treatment?

Several clinical trials to establish standard treatment modality for ovarian cancers included a high abundance of patients with serous histologic tumors, which were quite sensitive to platinum-based chemotherapy. On the other hand, ovarian tumor with rare histologic subtypes such as clear cell or mucinous tumors have been recognized to show chemo-resistant phenotype, leading to poorer prognosis. Especially, clear cell carcinoma of the ovary (CCC) is a distinctive tumor, deriving from endometriosis or clear cell adenofibroma, and response rate to platinum-based therapy is extremely low. It was implied that complete surgical staging enabled us to distinguish a high risk group of recurrence in CCC patients whose disease was confined to the ovary (pT1M0); however, complete surgical staging procedures could not lead to improved survival. Moreover, the status of peritoneal cytology was recognized as an independent prognostic factor in early-staged CCC patients, even after complete surgical staging. In advanced cases with CCC, the patients with no residual tumor had significantly better survival than those with the tumor less than 1 cm or those with tumor diameter more than 1 cm. Therefore, the importance of achieving no macroscopic residual disease at primary surgery is so important compared with other histologic subtypes. On the other hand, many studies have shown that conventional platinum-based chemotherapy regimens yielded a poorer prognosis in patients with CCC than in patients with serous subtypes. The response rate by paclitaxel plus carboplatin (TC) was slightly higher, ranging from 22% to 56%, which was not satisfactory enough. Another regimen for CCC tumors is now being explored: irinotecan plus cisplatin, and molecular targeting agents. In this review article, we discuss the surgical issues for early-staged and advanced CCC including possibility of fertility-sparing surgery, and the chemotherapy for CCC disease.

Exploiting p70 S6 kinase as a target for ovarian cancer

INTRODUCTION

The p70 S6 kinase (p70(S6K)) is frequently active in ovarian and a wide range of cancer types, and it has a crucial role in several processes considered hallmarks of cancer. Therefore, blocking p70(S6K) expression or activity may present a promising strategy for anticancer treatment.

AREAS COVERED

The current understanding of the molecular mechanisms that govern p70(S6K) regulation as well as its tumorigenic effects, which are involved in the initiation and progression in ovarian cancer, in particular the emerging new role of p70(S6K) in cell migration, which is a prerequisite of tumor metastasis. The p70(S6K) cellular substrates and/or interacting proteins. The current state of drugs that target this kinase, either alone or in combination with other targeted agents.

EXPERT OPINION

Targeting p70(S6K) through the use of small-molecule inhibitors, microRNAs and natural compounds may represent a beneficial new avenue for cancer therapy and opens new areas of investigation in p70(S6K) biology.