Recurrent ovarian cancer

Polycomb Repressor Complex 1 (PRC1) in ovarian cancer: A scoping literature review

High grade serous carcinoma (HGSC) is the most common and the deadliest histologic subtype of epithelial ovarian cancer. HGSC is a therapeutic challenge, as it recurs in 80 % of patients diagnosed, often as chemoresistant disease. The mechanism of this chemoresistance is not fully elucidated, but it is partly attributed to the ability of HGSC to maintain a stem-like phenotype that enables development of resistance to current therapies. Polycomb Repressor Complexes 1 and 2 (PRC1/2) have been implicated in the maintenance of the stem cell compartment through silencing tumor suppressor genes and regulating stem cells. These complexes are comprised of multiple polycomb group (PcG) proteins that play a role in normal development, and when deregulated contribute to the development of cancer [2]. Proteins included in PRC1 include B lymphoma mouse Moloney leukemia virus insertion region (BMI1), RING1, and chromobox (CBX) proteins. We aimed to review each of the protein components of PRC1 and their mechanistic relationships to promoting chemoresistant recurrences and propagation of ovarian cancer. Where possible, we reviewed therapeutic investigations of these proteins. We utilized a scoping literature review through Covidence to identify 42 articles meeting criteria for inclusion. The authors identified four relevant articles and the Yale MeSH Analysis Grid Generator was used to establish additional keywords and heading terms. A medical librarian used these terms and articles to draft an initial search strategy within each of the following databases: MEDLINE, Embase, Cochrane Library, and Web of Science Core Collection, yielding 439 articles based on title and abstract. Abstracts were independently reviewed by the authors, identifying 77 articles for full text review, of which 35 were ultimately excluded, leaving 42 articles for full review. Our review identified the currently known mechanisms of the subunits of PRC1 that contribute to HGSC development, recurrence, and chemoresistance. By compiling a comprehensive review of available scientific knowledge, we support and direct further investigation into PRC1 that can affect meaningful advances in the treatment of HGSC.

Knocking down RAD51AP1 enhances chemosensitivity by inhibiting the self-renewal of CD133 positive ovarian cancer stem-like cells

PURPOSE

This study was designed to investigate the function of RAD51AP1 in the self-renewal and chemosensitivity of CD133 positive (CD133+) ovarian cancer (OC) stem-like cells.

METHODS

CD133+ (CD133 positive) OVCAR4 and CD133 negative (CD133-) OVCAR4 cells were separated from OVCAR4 by flow cytometry. Then, the separated CD133+OVCAR4 cells were divided into the following groups: Vector group; RAD51AP1 group; siNC group; si-RAD51AP1 group. Next, sphere-formation assay and colony forming assay were used to evaluate the self-renewal and proliferation ability of cells; western blot to detect the expression of RAD51AP1, transforming growth factor beta 1 (TGF-β1) and SMAD4 proteins in tissues and cells; qRT-PCR to assess the mRNA levels of sex-determining region Y-box 2 (SOX2), octamer-binding transcription factor 4 (OCT4), NANOG and Kruppel-like factor 4 (KLF4).

RESULTS

The performance of CD133+OVCAR4 cells was much better than that of CD133-OVCAR4 cells in sphere-formation assay and colony forming assay. Besides, compared with adjacent group and CD133-OVCAR4 cells, the expression level of RAD51AP1 increased significantly in OC group and CD133+OVCAR4 cells. Moreover, the over-expression of RAD51AP1 promoted the self-renewal and proliferation of CD133+OVCAR4 cells. On the contrary, knocking down the expression level of RAD51AP1 could inhibit the self-renewal and proliferation of CD133+OVCAR4 cells and improve the sensitivity of cells to chemotherapy drugs.

CONCLUSION

The findings of this study showed that RAD51AP1 was highly expressed in OC tissue and CD133+OVCAR4 cells, and regulated the self-renewal and chemosensitivity of tumor cells through the TGF-β1/SMAD4 signaling pathway.

Assessment of the efficacy and safety of anlotinib for the treatment of recurrent epithelial ovarian cancer

OBJECTIVE

The current research aims to evaluate the efficacy and safety of anlotinib, an orally administered small-molecular tyrosine kinase inhibitor (TKI), in the treatment of recurrent epithelial ovarian cancer (EOC).

METHODS

Patients with recurrent EOC subjected to treatment with anlotinib in Fourth Hospital of Hebei Medical University from 2020 to 2022 were included. The evaluation involved a thorough review of medical records, focusing on parameters such as the objective response rate (ORR), disease control rate (DCR), survival outcomes, and safety profile.

RESULTS

This study recorded 51 patients, with 26 patients undergoing anlotinib monotherapy. The median progression-free survival (PFS) was 4.0 months, whereas the median overall survival (OS) was not reached. Seven cases underwent a combined treatment of anlotinib with chemotherapy. Among them, two patients achieved partial response (PR), two were categorized as stable disease (SD), and three were identified as having progressive disease (PD). The ORR and DCR were 28.5% (2/7) and 57.1% (4/7), respectively. Additionally, 18 cases received anlotinib maintenance therapy, and the median PFS and the median OS were 7.0 months and 25.5 months, respectively. The most prevalent adverse effects included fatigue (38.6%), hypertension (27.3%), nausea and vomiting (25.0%) and hand-foot syndrome (25.0%).

CONCLUSION

Anlotinib demonstrated mild efficacy in the treatment of recurrent EOC, whether employed as monotherapy, chemotherapy-combined therapy, or maintenance therapy. The safety profile was proven manageable and well-tolerated, suggesting that anlotinib may emerge as a viable and novel treatment option for recurrent EOC.

Targeted DNA sequencing of high-grade serous ovarian carcinoma reveals association of TP53 mutations with platinum resistance when combined with gene expression

High-grade serous ovarian carcinoma (HGSC) is the most common subtype of ovarian cancer and is among the most fatal gynecological malignancies worldwide, due to late diagnosis at advanced stages and frequent therapy resistance. In 47 HGSC patients, we assessed somatic and germline genetic variability of a custom panel of 144 known or suspected HGSC-related genes by high-coverage targeted DNA sequencing to identify the genetic determinants associated with resistance to platinum-based therapy. In the germline, the most mutated genes were DNAH14 (17%), RAD51B (17%), CFTR (13%), BRCA1 (11%), and RAD51 (11%). Somatically, the most mutated gene was TP53 (98%), followed by CSMD1/2/3 (19/19/36%), and CFTR (23%). Results were compared with those from whole exome sequencing of a similar set of 35 HGSC patients. Somatic variants in TP53 were also validated using GENIE data of 1287 HGSC samples. Our approach showed increased prevalence of high impact somatic and germline mutations, especially those affecting splice sites of TP53, compared to validation datasets. Furthermore, nonsense TP53 somatic mutations were negatively associated with patient survival. Elevated TP53 transcript levels were associated with platinum resistance and presence of TP53 missense mutations, while decreased TP53 levels were found in tumors carrying mutations with predicted high impact, which was confirmed in The Cancer Genome Atlas data (n = 260). Targeted DNA sequencing of TP53 combined with transcript quantification may contribute to the concept of precision oncology of HGSC. Future studies should explore targeting the p53 pathway based on specific mutation types and co-analyze the expression and mutational profiles of other key cancer genes.

Combined aqupla, paclitaxel liposome, and docetaxel treatment: survival and biomarker outcomes in recurrent ovarian cancer patients

As one lethal malignancy in women's reproductive systems, ovarian cancer (OC) is frequently detected at an advanced phase during diagnosis. when the disease has spread widely. The absence of obvious symptoms and powerful screening tools in the early stages makes treatment difficult and the prognosis poor. Despite the clinical remission that can be achieved in some patients after initial treatment, the recurrence rate is conspicuous, posing a considerable challenge in treating recurrent OC (ROC). In the retrospective analysis, we compared the effects of two treatment regimens, aqupla combined with paclitaxel liposome (NP group) versus aqupla combined with docetaxel (ND group), on survival and biomarkers in patients with ROC. The study included 121 OC patients, and clinical data were collected through an electronic medical record system, outpatient review records, and a follow-up record system. The results revealed a notably higher overall remission rate in the ND group than the NP group, but revealed no notable inter-group discrepancy in toxicities, implying that the aqupla combined with docetaxel regimen may be more effective in platinum-sensitive ROC patients. Additionally, post-treatment CA125 levels were lower in patients in the ND group, suggesting that the regimen may be more effective in reducing tumour load. Survival analysis further revealed that treatment regimen, FIGO stage, number of recurrent lesions, and pretreatment CA125 level were independent prognostic factors affecting patients' 5-year OS and PFS. Overall for ROC patients, especially platinum-sensitive patients, the aqupla in combination with docetaxel regimen provided an improved survival benefit with a comparable safety profile, highlighting the importance of individualised treatment strategies.

Current treatment strategies for ovarian cancer in the East Asian Gynecologic Oncology Trial Group (EAGOT)

Ovarian cancer, notable for its severe prognosis among gynecologic cancers, has seen substantial progress in treatment approaches recently. Enhanced protocols in chemotherapy and the introduction of poly (ADP-ribose) polymerase (PARP) inhibitors for maintenance therapy have markedly improved outcomes for patients with specific genetic profiles, such as those positive for BRCA mutations or exhibiting homologous recombination deficiency (HRD). Additionally, the method of intraperitoneal chemotherapy administration has emerged as a valuable alternative to traditional transvenous routes, showing promise for wider clinical adoption. The field of surgery has also evolved, with increasing exploration into the benefits and feasibility of laparoscopic methods over more invasive traditional surgeries, aiming for complete tumor removal but with reduced patient impact. The hereditary nature of ovarian cancer underscores the importance of genetic testing, which has become integral in tailoring treatment strategies, particularly in determining suitability for PARP inhibitors. The formation of the East Asian Gynecologic Oncology Trial Group (EAGOT) aims to optimize treatment across Japan, Korea, China, and Taiwan. The ovarian cancer committee of EAGOT shared the current policies, focusing on 5 topics: 1) strategies for maintenance therapy after initial surgery and chemotherapy, 2) drug regimens for platinum-sensitive and platinum-resistant recurrence, 3) intraperitoneal chemotherapy, 4) laparoscopic surgery as an alternative to laparotomy, and 5) current status of genetic testing (BRCA, HRD, and panel tests) for ovarian cancer and its prospects. EAGOT's multi-national trials aim to harmonize these evolving treatment strategies, ensuring that the latest and most effective protocols are accessible across the region, thereby significantly impacting patient outcomes in East Asia.

The CHK1 inhibitor prexasertib in BRCA wild-type platinum-resistant recurrent high-grade serous ovarian carcinoma: a phase 2 trial

The multi-cohort phase 2 trial NCT02203513 was designed to evaluate the clinical activity of the CHK1 inhibitor (CHK1i) prexasertib in patients with breast or ovarian cancer. Here we report the activity of CHK1i in platinum-resistant high-grade serous ovarian carcinoma (HGSOC) with measurable and biopsiable disease (cohort 5), or without biopsiable disease (cohort 6). The primary endpoint was objective response rate (ORR). Secondary outcomes were safety and progression-free survival (PFS). 49 heavily pretreated patients were enrolled (24 in cohort 5, 25 in cohort 6). Among the 39 RECISTv1.1-evaluable patients, ORR was 33.3% in cohort 5 and 28.6% in cohort 6. Primary endpoint was not evaluable due to early stop of the trial. The median PFS was 4 months in cohort 5 and 6 months in cohort 6. Toxicity was manageable. Translational research was an exploratory endpoint. Potential biomarkers were investigated using pre-treatment fresh biopsies and serial blood samples. Transcriptomic analysis revealed high levels of DNA replication-related genes (POLA1, POLE, GINS3) associated with lack of clinical benefit [defined post-hoc as PFS < 6 months]. Subsequent preclinical experiments demonstrated significant cytotoxicity of POLA1 silencing in combination with CHK1i in platinum-resistant HGSOC cell line models. Therefore, POLA1 expression may be predictive for CHK1i resistance, and the concurrent POLA1 inhibition may improve the efficacy of CHK1i monotherapy in this hard-to-treat population, deserving further investigation.

Sulforaphene suppressed cell proliferation and promoted apoptosis of COV362 cells in endometrioid ovarian cancer

Aim

N6-methyladenosine (m6A) RNA methylation exerts a regulatory effect on endometrioid ovarian cancer (EOC), but the specific m6A regulator genes in EOC remain to be explored. This study investigated that sulforaphene (Sul) is implicated in EOC development by regulating methyltransferase-like 3 (METTL3).

Methods

The dysregulated m6A RNA methylation genes in EOC were determined by methylated RNA immunoprecipitation (MeRIP-seq) and RNA sequencing. The roles of METTL3 and/or Sul on viability, proliferative ability, cell cycle, and apoptosis of EOC cells were determined by MTT, colony formation, flow cytometry, and TUNEL staining assay, respectively. The expression of METTL3 and apoptosis-related proteins in EOC cells was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot assays.

Results

Five m6A RNA methylation regulators (METTL3, ELF3, IGF2BP2, FTO, and METTL14) were differentially expressed in EOC, among which METTL3 had the highest expression level. Silencing METTL3 reduced the clonal expansion and viability of EOC cells, and caused the cells to arrest in the G0/G1 phase. This also promoted apoptosis in the EOC cells and activated the FAS/FADD and mitochondrial apoptosis pathways. In contrast, overexpressing METTL3 had the opposite effect. Sul, in a dose-dependent manner, reduced the viability of EOC cells but promoted their apoptosis. Sul also increased the levels of IGF2BP2 and FAS, while decreasing the levels of KRT8 and METTL3. Furthermore, Sul was able to reverse the effects of METTL3 overexpression on EOC cells.

Conclusions

Sul could suppress cell proliferation and promote apoptosis of EOC cells by inhibiting the METTL3 to activate the FAS/FADD and apoptosis-associated pathways.

A platinum(II) complex HY1-Pt overcomes cisplatin-induced resistance and attenuates metastasis of epithelial ovarian cancer by cancer cell stemness inhibition

Tumor recurrence, acquired resistance and metastasis have severely limited the effect of clinical treatments for epithelial ovarian cancer. Recent researches reveal that cancer stem cells play important roles in the process of cisplatin-induced resistance and cancer cell metastasis. A platinum(II) complex (HY1-Pt) owning casein kinase 2 specificity reported in our recent research was herein applied to treat cisplatin-sensitive and cisplatin-resistant epithelial ovarian cancers, respectively, anticipating to achieve high anti-tumor efficacy. HY1-Pt showed highly efficient anti-tumor effect with low toxicity for either cisplatin-sensitive or cisplatin-resistant epithelial ovarian cancer both in vitro and in vivo. Biological studies indicated that HY1-Pt as a casein kinase 2 inhibitor could effectively overcome cisplatin resistance through the signaling pathway of Wnt/β-catenin by inhibiting expression of the signature genes of cancer stemness cells in A2780/CDDP cells. Moreover, HY1-Pt could suppress tumor migration and invasion in vitro and in vivo, further proving that HY1-Pt can be a potent novel platinum(II) agent for cisplatin-resistant epithelial ovarian cancer treatment.

Human macrophage-engineered vesicles for utilization in ovarian cancer treatment

Background

Ovarian cancer is a deadly female malignancy with a high rate of recurrent and chemotherapy-resistant disease. Tumor-associated macrophages (TAMs) are a significant component of the tumor microenvironment and include high levels of M2-protumor macrophages that promote chemoresistance and metastatic spread. M2 macrophages can be converted to M1 anti-tumor macrophages, representing a novel therapeutic approach. Vesicles engineered from M1 macrophages (MEVs) are a novel method for converting M2 macrophages to M1 phenotype-like macrophages.

Methods

Macrophages were isolated and cultured from human peripheral blood mononuclear cells. Macrophages were stimulated to M1 or M2 phenotypes utilizing LPS/IFN-γ and IL-4/IL-13, respectively. M1 MEVs were generated with nitrogen cavitation and ultracentrifugation. Co-culture of ovarian cancer cells with macrophages and M1 MEVs was followed by cytokine, PCR, and cell viability analysis. Murine macrophage cell line, RAW264.7 cells were cultured and used to generate M1 MEVs for use in ovarian cancer xenograft models.

Results

M1 MEVs can effectively convert M2 macrophages to an M1-like state both in isolation and when co-cultured with ovarian cancer cells in vitro, resulting in a reduced ovarian cancer cell viability. Additionally, RAW264.7 M1 MEVs can localize to ovarian cancer tumor xenografts in mice.

Conclusion

Human M1 MEVs can repolarize M2 macrophages to a M1 state and have anti-cancer activity against ovarian cancer cell lines. RAW264.7 M1 MEVs localize to tumor xenografts in vivo murine models.

Anlotinib Exerts Inhibitory Effects against Cisplatin-Resistant Ovarian Cancer In Vitro and In Vivo

Background: Anlotinib is a highly potent multi-target tyrosine kinase inhibitor. Accumulating evidence suggests that anlotinib exhibits effective anti-tumor activity against various cancer subtypes. However, the effects of anlotinib against cisplatin-resistant (CIS) ovarian cancer (OC) are yet to be elucidated. The objective of this study was to investigate the inhibitory effect of anlotinib on the pathogenesis of cisplatin-resistant OC. Materials and Methods: Human OC cell lines (A2780 and A2780 CIS) were cultured and treated with or without anlotinib. The effects of anlotinib on cell proliferation were determined using cell-counting kit-8 and colony-formation assays. To evaluate the invasion and metastasis of OC cells, we performed wound-healing and transwell assays. The cell cycle was analyzed via flow cytometry. A xenograft mouse model was used to conduct in vivo studies to verify the effects of anlotinib. The expression of Ki-67 in the tumor tissue was detected via immunohistochemistry. Quantitative real-time polymerase chain reaction and Western blotting were used to measure the mRNA and protein levels. Results: Our study revealed that anlotinib significantly inhibited the proliferation, migration, and invasion of A2780 and A2780 CIS in a dose-dependent way in vitro (p < 0.05). Through R software ‘limma’ package analysis of GSE15372, it was found that, in comparison with A2780, PLK2 was expressed in significantly low levels in the corresponding cisplatin-resistant strains. The ERK1/2/Plk2 signaling axis mediates the inhibitory effect of anlotinib on the proliferation and migration of ovarian cancer cell lines. Moreover, our research found that anlotinib effectively inhibited the growth of tumor cells in an OC xenograft mouse model. Conclusions: In this study, anlotinib showed excellent inhibitory effects against cisplatin-resistant OC both in vitro and in vivo. These results add to the growing body of evidence supporting anlotinib as a potential anticancer agent against OC.

Complex molecular profile of DNA repair genes in epithelial ovarian carcinoma patients with different sensitivity to platinum-based therapy

Epithelial ovarian carcinoma (EOC) is known for high mortality due to diagnosis at advanced stages and frequent therapy resistance. Previous findings suggested that the DNA repair system is involved in the therapeutic response of cancer patients and DNA repair genes are promising targets for novel therapies. This study aimed to address complex inter-relations among gene expression levels, methylation profiles, and somatic mutations in DNA repair genes and EOC prognosis and therapy resistance status. We found significant associations of DUT expression with the presence of peritoneal metastases in EOC patients. The high-grade serous EOC subtype was enriched with TP53 mutations compared to other subtypes. Furthermore, somatic mutations in XPC and PRKDC were significantly associated with worse overall survival of EOC patients, and higher FAAP20 expression in platinum-resistant than platinum-sensitive patients was observed. We found higher methylation of RAD50 in platinum-resistant than in platinum-sensitive patients. Somatic mutations in BRCA1 and RAD9A were significantly associated with higher RBBP8 methylation in platinum-sensitive compared to platinum-resistant EOC patients. In conclusion, we discovered associations of several candidate genes from the DNA repair pathway with the prognosis and platinum resistance status of EOC patients, which deserve further validation as potential predictive biomarkers.

Therapy for Recurrent High-Grade Epithelial Ovarian Cancer—The Current Status and Future Trends

Ovarian malignancy is the seventh most frequently diagnosed cancer among women. The most common type is epithelial ovarian cancer. Several subtypes with distinct biological and molecular properties exist, and there is inconsistency in availability of and access to different modalities of treatment. The standard first-line management is combining surgery and platinum-based chemotherapy. Most of them are diagnosed at an advanced stage due to which they have poor outcomes. The existing screening tests have a low predictive value. Even with the best available upfront treatment, high rates of recurrences are observed. As a result, there have been major advances in the treatment of recurrences with the development of anti-angiogenic agents and PARP inhibitors. It has led to the improvement in survival and quality of life among the relapsed epithelial ovarian cancers. This review is focused on the management of recurrent epithelial ovarian cancers and future directions based on current evidence. The application of a personalized and structured approach will meaningfully bring changes in the paradigm of care in these groups of patients.

Case Report and Review of Literature: Camrelizumab Combined with Fuzuloparib and Apatinib for Platinum-Resistant Recurrent Ovarian Cancer

Background

The mortality rate of ovarian cancer (OC) ranks first among female genital tract malignant tumors, which seriously threatens women's life and health. Because of its insidious onset and poor prognosis, it has become a thorny problem in the clinic, especially for patients with platinum-resistant recurrent ovarian cancer (PROC). In recent years, the medical treatment of OC has made gratifying results, bringing hope to the patients.

Case Description

A 54-year-old OC patient who has failed previous neoadjuvant chemotherapy, cytoreductive surgery, and postoperative chemotherapy was diagnosed with PROC. Then she received combination treatment of fuzuloparib (100mg PO BID), apatinib (250mg PO QD), and camrelizumab (200mg IV Q3W) for every 3-week cycle in a Phase II study for PROC patients. In the phase II study, her condition stabilized, responded well to treatment with a sharp decrease by 91.14% of target lesions and disappearances of non-target lesions, and continued to receive regular treatment with progression-free survival exceeding 15 months and no serious adverse events.

Conclusion

The present case proves PROC patients might have a sustained response to triplet combination with camrelizumab, combined with fuzuloparib and apatinib.

Role of 18F FDG PET/CT in evaluation of post-operative ovarian carcinoma

Background

We evaluated the sensitivity, specificity and accuracy of fluorine-18-fluorodeoxyglucose with positron emission tomography/computed tomography (18F-FDG-PET/CT) in a group of patients with suspicion of ovarian cancer recurrence. It is considered a diagnostic dilemma, particularly in the 2 years following first-line therapy. CA125 serum levels computed tomography (CT) and other modalities are used during routine follow-up. These traditional modalities could provide a significant number of false-negative or equivocal results even in the presence of elevated CA125 levels. So the performance of 18F-FDG-PET/CT is essential for the optimal diagnosis of recurrence and treatment planning.

Results

Studying PET/CT behaviour in the detection of ovarian cancer recurrence, 18F-FDG-PET/CT had an accuracy of 98% with sensitivity and specificity of 98% and 100%, respectively. 18F-FDG-PET/CT had a PPV of 100% and NPV of 83%. While studying the CA125 level (> 35 U/ml) to detect the ovarian cancer recurrence during patient follow-up, the CA125 level had an accuracy of 50% with a sensitivity ratio and specificity ratio of 47% and 80%, respectively. CA-125 level had a PPV of 95% and NPV of 14%. In comparison between conventional CT and PET/CT studies, the PET/CT diagnosed local tumor recurrence in 16 patients (32%), while CT scan diagnosed local tumor recurrence in only 3 patients (6%), and PET/CT detected peritoneal recurrence in 34 patients (68%). CT scan found peritoneal deposits in 11 patients (22%), also the PET/CT showed suspicious abdominal LNS in 22 patients (44%) while, CT scan showed suspicious abdominal LNS in 4 patients (8%), and PET/CT showed suspicious pelvic LNS in 16 patients (32%). CT scan showed suspicious pelvic LNS in 7 patients (14%). PET/CT detected distant organ metastases in 18 patients (36%). CT scan detected distant organ metastasis in only 8 patients (16%). Comparison between CT and PET/CT in 32 follow-up cases for the detection of local tumor recurrence, peritoneal deposits, suspicious abdominal/pelvic LNs and distant organ metastasis. There was a statistically significant difference between CT and PET/CT the end results (p < 0.0001, p = 0.0047, p = 0.001, p = 0.03).

Conclusions

18F-FDG-PET/CT is more sensitive in detection and localization of ovarian cancer recurrence and more superior than the other imaging modalities.

Assessment of the diagnostic and prognostic relevance of ACAT1 and CE levels in plasma, peritoneal fluid and tumor tissue of epithelial ovarian cancer patients - a pilot study

Background

Abnormal accumulation of acyl-CoA cholesterol acyltransferase-1 (ACAT1) and ACAT1-mediated cholesterol esterified with fatty acids (CE) contribute to cancer progression in various cancers. Our findings of increased CE and ACAT1 levels in epithelial ovarian cancer (EOC) cell lines prompted us to investigate whether such an increase occurs in primary clinical samples obtained from human subjects diagnosed with EOC. We evaluated the diagnostic/prognostic potential of ACAT1 and CE in EOC by: 1) assessing ACAT1 and CE levels in plasma, peritoneal fluid, and ovarian/tumor tissues; 2) assessing diagnostic performance by Receiver Operating Characteristic (ROC) analysis; and 3) comparing expression of ACAT1 and CE with that of tumor proliferation marker, Ki67.

Methods

ACAT1 protein levels in plasma, peritoneal fluid and tissue were measured via enzyme-linked immunosorbent assay. Tissue expression of ACAT1 and Ki67 proteins were confirmed by immunohistochemistry and mRNA transcript levels were evaluated using quantitative real-time polymerase chain reaction (qRT-PCR). CE levels were assessed in plasma, peritoneal fluid (colorimetric assay) and in tissue (thin layer chromatography).

Results

Preoperative levels of ACAT1 and CE on the day of surgery were significantly higher in tissue and peritoneal fluid from EOC patients vs. the non-malignant group, which included subjects with benign tumors and normal ovaries; however, no significant differences were observed in plasma. In tissue and peritoneal fluid, positive correlations were observed between CE and ACAT1 levels, as well as between ACAT1/CE and Ki67.

Conclusions

ACAT1 and CE accumulation may be linked to the aggressive potential of EOC; therefore, these mediators may be useful biomarkers for EOC prognosis and target-specific treatments.

Involvement of Cancer Stem Cells in Chemoresistant Relapse of Epithelial Ovarian Cancer Identified by Transcriptome Analysis

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy. Despite the initial resection and chemotherapeutic treatment, relapse is common, which leads to poor survival rates in patients. A primary cause of recurrence is the persistence of ovarian cancer stem cells (OCSCs) with high tumorigenicity and chemoresistance. To achieve a better therapeutic response in EOC relapse, the mechanisms underlying acquired chemoresistance associated with relapse-initiating OCSCs need to be studied. Transcriptomes of both chemosensitive primary and chemoresistant relapse EOC samples were obtained from ICGC OV-AU dataset for differential expression analysis. The upregulated genes were further studied using KEGG and GO analysis. Significantly increased expression of eighteen CSC-related genes was found in chemoresistant relapse EOC groups. Upregulation of the expression in four hub genes including WNT3A, SMAD3, KLF4, and PAX6 was verified in chemoresistant relapse samples via immunohistochemistry staining, which confirmed the existence and enrichment of OCSCs in chemoresistant relapse EOC. KEGG and GO enrichment analysis in microarray expression datasets of isolated OCSCs indicated that quiescent state, increased ability of drug efflux, and enhanced response to DNA damage may have caused the chemoresistance in relapse EOC patients. These findings demonstrated a correlation between OCSCs and acquired chemoresistance and illustrated potential underlying mechanisms of OCSC-initiated relapse in EOC patients. Meanwhile, the differentially expressed genes in OCSCs may serve as novel preventive or therapeutic targets against EOC recurrence in the future.

Treatment Experience and Predictive Factors Associated with Response in Platinum-Resistant Recurrent Ovarian Cancer: A Retrospective Single-Institution Study

Ovarian cancer (OC) represents the most common and lethal gynecologic malignancy, due to its increased incidence and mortality rate. It is usually diagnosed in advanced stages and, even though surgery and platinum-based treatments are initially efficient, recurrences emerge in over 70% of cases. Although there are multiple options of chemotherapy drugs from which to choose, little is known regarding the best strategy for prolonged survival. Thus, this study aimed to assess the effect that most frequently used chemotherapeutic regimens have upon time-to-treatment-failure (TTF) from the first line and beyond, considering clinical and biological factors which influence the treatment outcome of platinum-resistant recurrent OC. We retrospectively analyzed data from 78 patients diagnosed with platinum-resistant OC, who underwent chemotherapy-based treatment with or without anti-angiogenic therapy at OncoHelp Oncology Center, Romania (January 2016–February 2021). Our study identified positive predictive factors for TTF related to histology (serous carcinoma subtype), anthropometry (age over 60 for patients treated with topotecan with or without bevacizumab), renal function (creatinine levels between 0.65 and 1 mg/dL for patients treated with regimens containing bevacizumab and pegylated liposomal doxorubicin) and treatment choice (bevacizumab in combination with pegylated liposomal doxorubicin or topotecan used from the first line and beyond).

Pretreatment with LCK inhibitors chemosensitizes cisplatin-resistant endometrioid ovarian tumors

Background

Ovarian cancer is the most fatal gynecologic malignancy in the United States. While chemotherapy is effective in the vast majority of ovarian cancer patients, recurrence and resistance to standard systemic therapy is nearly inevitable. We discovered that activation of the non-receptor tyrosine kinase Lymphocyte Cell-Specific Protein-Tyrosine Kinase (LCK) promoted cisplatin resistance. Here, we hypothesized that treating high grade, platinum resistant endometrioid cancer cells with an LCK inhibitor (LCKi) followed by co-treatment with cisplatin would lead to increased cisplatin efficacy. Our objective was to assess clinical outcomes associated with increased LCK expression, test our hypothesis of utilizing LCKi as pre-treatment followed by co-treatment with cisplatin in platinum resistant ovarian cancer in vitro, and evaluate our findings in vivo to assess LCKi applicability as a therapeutic agent.

Results

Kaplan-Meier (KM) plotter data indicated LCK expression is associated with significantly worse median progression-free survival (HR 3.19, p = 0.02), and a trend toward decreased overall survival in endometrioid ovarian tumors with elevated LCK expression (HR 2.45, p = 0.41). In vitro, cisplatin resistant ovarian endometrioid cells treated first with LCKi followed by combination LCKi-cisplatin treatment showed decreased cell viability and increased apoptosis. Immunoblot studies revealed LCKi led to increased expression of phosphorylated H2A histone family X (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma$$\end{document}γ-H2AX), a marker for DNA damage. In vivo results demonstrate treatment with LCKi followed by LCKi-cisplatin led to significantly slowed tumor growth.

Conclusions

We identified a strategy to therapeutically target cisplatin resistant endometrioid ovarian cancer leading to chemosensitization to platinum chemotherapy via treatment with LCKi followed by co-treatment with LCKi-cisplatin.

A Retrospective Observational Study of Anlotinib in Patients with Platinum-Resistant or Platinum-Refractory Epithelial Ovarian Cancer

Objective

Anlotinib, an oral small-molecular tyrosine kinase inhibitor (TKI) on tumor angiogenesis and growth, has a wide spectrum of inhibitory effects on targets such as vascular endothelial growth factor receptors 2/3 (VEGFR2/3), etc. The efficacy and safety of anlotinib in the treatment of platinum-resistant or platinum-refractory ovarian cancer were evaluated.

Patients and Methods

Patients with platinum-resistant or platinum-refractory ovarian cancer that treated with anlotinib in the Affiliated Cancer Hospital of Zhengzhou University from May 2018 to March 2020 were included. Medical records were reviewed in terms of objective response, survival outcomes, and safety.

Results

A total of 38 patients were analyzed. The median progression-free survival and the median overall survival were 7.7 months (95% CI: 6.7–8.7) and 16.5 months (95% CI: 13.3–19.7), respectively. About 17 patients received anlotinib monotherapy, and the median progression-free survival was 7.7 months (95% CI: 6.3–9.1). A total of 19 cases received anlotinib plus chemotherapy with a median progression-free survival of 8.0 months (95% CI: 4.8–11.2). A total of 2 cases received anlotinib plus anti-PD-1 antibody pembrolizumab, and 1 case had partial response, the other progressive disease. The objective response rate was 42.1% while the disease control rate was 86.8%. A total of 5 patients experienced dose reduction from 12 mg to 10 mg because of adverse effects. The most common adverse effects were hypertension (31.6%), fatigue (28.9%), anorexia (26.3%) and hand-foot syndrome (23.7%). No treatment-related deaths were recorded.

Conclusion

Anlotinib produced moderate improvements in progression-free survival and overall survival in patients with platinum-resistant or platinum-refractory ovarian cancer. It indicates that anlotinib maybe a new treatment option for patients with platinum-resistant or platinum-refractory ovarian cancer.

Revisiting chemoresistance in ovarian cancer: Mechanism, biomarkers, and precision medicine

Among the gynecological cancers, ovarian cancer is the most lethal. Its therapeutic options include a combination of chemotherapy with platinum-based compounds and cytoreductive surgery. Most ovarian cancer patients exhibit an initial response to platinum-based therapy, however, platinum resistance has led to up to 80% of this responsive cohort becoming refractory. Ovarian cancer recurrence and drug resistance to current chemotherapeutic options is a global challenge. Chemo-resistance is a complex phenomenon that involves multiple genes and signal transduction pathways. Therefore, it is important to elucidate on the underlying molecular mechanisms involved in chemo-resistance. This inform decisions regarding therapeutic management and help in the identification of novel and effective drug targets. Studies have documented the individual biomarkers of platinum-resistance in ovarian cancer that are potential therapeutic targets. This review summarizes the molecular mechanisms of platinum resistance in ovarian cancer, novel drug targets, and clinical outcomes.

Tamoxifen use in recurrent ovarian cancer in a Chinese population: A 15 -year clinical experience in a tertiary referral center

Aim

To review the clinical use and the effectiveness of tamoxifen in patients with advanced or recurrent ovarian cancer.

Methods

A retrospective review of clinical records was conducted in patients who received tamoxifen for the treatment of ovarian cancer between 2002 and 2016. We reviewed the clinical setting that it was given, duration of use, patients' tolerability, clinical benefit and progression‐free survival. We also attempted to identify predictive markers for response.

Results

A total of 92 patients received tamoxifen during this 15‐year period. The patients received a median of 2.5 lines of chemotherapy before switching to tamoxifen, and they remained on tamoxifen for a median of 5.6 months (range 0–85 months), with 24 patients receiving it for more than 12 months. Seventy‐six patients continued on tamoxifen for more than 2 months. In this group, 75 patients had an evaluable response, either by CA 125 or clinically and clinical benefit rate (defined as complete, partial response and static disease) was seen in 42 patients (56%), with majority of patients having static disease. The median progression‐free survival was 5.3 months (95% confidence interval, 2.6–8.1). Tamoxifen was well tolerated. Hormone receptor status was not demonstrated to predict response.

Conclusion

Patients with advanced ovarian cancer who have failed previous lines of chemotherapy may achieve static disease with tamoxifen with minimal side effects. Tamoxifen may still have a role in the era of molecular target therapy.

High Expression of Nuclear Transcription Factor-κB is Associated with Cisplatin Resistance and Prognosis for Ovarian Cancer

Background

Abnormal activation of the nuclear transcription factor-κB (NF-κB) signaling pathway plays a crucial role in the chemoresistance of tumor cells. This study aimed to explore the significance of NF-κB in the chemoresistance of ovarian cancer.

Materials

We performed immunohistochemical staining for evaluating the expression of NF-κB in cancer tissues. The MTT assay was performed for analyzing cell proliferation, Western blotting was performed to quantify NF-κB p65, and flow cytometry was used to determine the apoptosis rate.

Results

Nuclear NF-κB p65 over-expression was closely associated with ovarian cancer with advanced FIGO stage, residual disease ≥1 cm, low histologic grade, platinum resistance and refractory, chemotherapy resistance (P< 0.05). FIGO stage I–II and residual disease <1 cm were associated with complete response (CR) to chemotherapy, while FIGO stage I–II, residual disease <1cm and absence of lymph node (LN) metastasis were associated with platinum sensitivity. In multivariate logistic regression, residual disease ≥1 cm was a risk factor for response to chemotherapy, while the over-expression of nuclear NF-κB p65 was a risk factor for sensitivity to chemotherapy. In the ROC curves, nuclear NF-κB p65 expression had the discriminative ability for sensitivity to chemotherapy (AUC = 0.637, P = 0.021). Furthermore, nuclear NF-κB p65 expression was an independent prognostic factor. Western blotting showed that NF-κB p65 level in cisplatin-resistant cells (C13* and A2780cp) was significantly higher than that in cisplatin-sensitive cells (OV2008 and A2780s) (P < 0.05), and this increased expression could be suppressed by NF-κB inhibitor-PDTC treatment. The proliferation inhibitory rates of cisplatin in C13* and A2780cp cells increased after PDTC treatment in a concentration-dependent manner. PDTC treatment could also enhance cisplatin-induced apoptosis.

Conclusion

NF-κB was associated with the clinicopathological features, chemoresistance, and prognosis of ovarian cancer. The NF-κB inhibitor PDTC can enhance cisplatin sensitivity of platinum-resistant C13* and A2780cp ovarian cancer cells.

Clinical relevance of cancer stem cell chemotherapeutic assay for recurrent ovarian cancer

Introduction

Disease recurrence and progression of ovarian cancer is common with the development of platinum-resistant or refractory disease. This is due in large part to the presence of chemo-resistant cancer stem cells (CSCs) that contribute to tumor propagation, maintenance, and treatment resistance. We developed a CSCs drug cytotoxicity assay (ChemoID) to identify the most effective chemotherapy treatment from a panel of FDA approved chemotherapies.

Methods

Ascites and pleural fluid samples were collected under physician order from 45 consecutive patients affected by 3rd-5th relapsed ovarian cancer. Test results from the assay were used to treat patients with the highest cell kill drugs, taking into consideration their health status and using dose reductions, as needed. A retrospective chart review of CT and PET scans was used to determine patients' outcomes for tumor response, time to recurrence, progression-free survival (PFS), and overall survival (OS).

Results

We observed that recurrent ovarian cancer patients treated with high-cell kill chemotherapy agents guided by the CSCs drug response assay had an improvement in the median PFS corresponding to 5.4 months (3rd relapse), 3.6 months (4th relapse), and 3.9 months (5th relapse) when compared to historical data. Additionally, we observed that ovarian cancer patients identified as non-responders by the CSC drug response assay had 30 times the hazard of death compared to those women that were identified as responders with respective median survivals of 6 months vs. 13 months. We also found that ChemoID treated patients on average had an incremental cost-effectiveness ratio (ICER) between -$18,421 and $7,241 per life-year saved (LYS).

Conclusions

This study demonstrated improved PFS and OS for recurrent ovarian cancer patients treated with assay-guided chemotherapies while decreasing the cost of treatment.

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Ovarian cancer progression and recurrence is mostly attributed to the presence of cancer stem cells (CSCs), which are chemo-resistant.

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Eliminating CSCs is a strategy that could improve patients' outcome.

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We developed a CSC drug cytotoxicity assay to identify the most effective chemotherapy treatment from a panel of FDA approved chemotherapies.

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Recurrent ovarian cancer patients treated with high-cell kill chemotherapy agents guided by the CSCs drug response assay had an improvement in the median PFS when compared to historical data.

Altered Organelle Calcium Transport in Ovarian Physiology and Cancer

Calcium levels have a huge impact on the physiology of the female reproductive system, in particular, of the ovaries. Cytosolic calcium levels are influenced by regulatory proteins (i.e., ion channels and pumps) localized in the plasmalemma and/or in the endomembranes of membrane-bound organelles. Imbalances between plasma membrane and organelle-based mechanisms for calcium regulation in different ovarian cell subtypes are contributing to ovarian pathologies, including ovarian cancer. In this review, we focused our attention on altered calcium transport and its role as a contributor to tumor progression in ovarian cancer. The most important proteins described as contributing to ovarian cancer progression are inositol trisphosphate receptors, ryanodine receptors, transient receptor potential channels, calcium ATPases, hormone receptors, G-protein-coupled receptors, and/or mitochondrial calcium uniporters. The involvement of mitochondrial and/or endoplasmic reticulum calcium imbalance in the development of resistance to chemotherapeutic drugs in ovarian cancer is also discussed, since Ca2+ channels and/or pumps are nowadays regarded as potential therapeutic targets and are even correlated with prognosis.

Effect of delayed palliative chemotherapy on survival of patients with recurrent ovarian cancer

For patients with recurrent ovarian cancer, the goals of chemotherapy include palliation of disease-related symptoms with minimum treatment-related side effects. However, there is currently a paucity of data regarding the initiation of palliative chemotherapy. This study aimed to compare the differences in survival rates and toxicities between patients with recurrent ovarian cancer who started palliative chemotherapy immediately versus those who received delayed chemotherapy. Through a retrospective chart review, patients who received more than three lines of chemotherapy were included. Based on the timing of third-line chemotherapy initiation, the patients were divided into two groups: delayed (DTG) and immediate (ITG) treatment groups. The chi-square test or Fisher’s exact tests, and t-test or Mann-Whitney U test were used for comparing variables, as appropriate. The Kaplan-Meier method was used for survival analysis. P-value of <0.05 was considered significant. Although there was no statistically significant difference, the total number of regimens and cycles was lower in the DTG than in the ITG. No differences in toxicities and survival rates were observed between the two groups. Overall, survival and toxicity did not differ significantly between the two groups. In a palliative care setting, our findings suggest that delaying the treatment had no adverse effect on survival. Despite the lack of evidence of a survival benefit with aggressive treatment, patients chose to continue chemotherapy. Because recurrent ovarian cancer is a complex condition, patients require sufficient explanation and time to fully understand the costs and benefits related to aggressive chemotherapy.

Cyclin H predicts the poor prognosis and promotes the proliferation of ovarian cancer

Background

Cell cycle dysregulation plays a key role in the pathogenesis of malignant tumors. As a part of the CDK-activating kinase (CAK) trimeric complex, cyclin H is necessary to regulate the cell cycle and proliferation. This investigation aims to characterize the clinical significance and the biological functions of cyclin H in ovarian cancer.

Methods

Immunohistochemical staining was performed on 60 ovarian cancer cases, and a correlation between cyclin H expression and the clinical characteristics of ovarian cancer was analyzed. The function of cyclin H in ovarian cancer was further explored using HO8910 cells and a subcutaneous xenograft model of nude mice.

Result

Cyclin H was slightly expressed in grade 1 ovarian cancer but highly expressed in grade 2 and grade 3 cancerous tissues. The Spearman's rank correlation analysis showed that the expression of cyclin H is positively correlated with the tumor grade, the FIGO stage, histological grade, and the peritoneal metastasis of ovarian cancer and is also positively correlated with the Ki67 and p-CDK2 in ovarian cancer. Additionally, we found that the five-year survival rate was higher in patients expressing low cyclin H than those expressing high cyclin H. Further, knockdown of cyclin H was achieved using an shRNA in HO8910 ovarian cancer cell line. Silencing cyclin H resulted in a G1/S cell cycle arrest in ovarian cancer cells suppressing its growth. The Ki67 expression was also decreased in cyclin H silenced ovarian cancer.

Conclusion

These results suggest that high expression of cyclin H predicts the poor prognosis and promotes the growth of ovarian cancer by regulating the cell cycle.

Oncogenic and drug-sensitive RET mutations in human epithelial ovarian cancer

Background

Epithelial ovarian cancer (EOC) is a highly lethal malignancy. Improvement in genetic characterization of EOC patients is required to propose new potential targets, since surgical resection coupled to chemotherapy, presents several limits such as cancer recurrence and drug resistance. Targeted therapies have more efficacy and less toxicity than standard treatments. One of the most relevant cancer-specific actionable targets are protein tyrosine kinases (PTKs) whose role in EOC need to be better investigated.

Methods

EOC genomic datasets are retrieved and analyzed. The biological and clinical significance of RET genomic aberrations in ovarian cancer context are investigated by a series of in vitro and in vivo experiments.

Results

Epithelial ovarian cancer sequencing projects identify recurrent genomic RET missense mutations in 1.98% of patients, ranking as the top-five hit among the 100 receptor tyrosine kinases-encoding genes. RET mutants R693H and A750T show oncogenic transformation properties in NIH3T3 cells. Introduction of the RET mutants into human EOC cells increases RET signaling, cell viability, anchorage-independent cell growth and tumor xenograft growth in nude mice, demonstrating that they are activating mutations. RET mutants significantly enhance the activation of RET and its downstream MAPK and AKT signaling pathway in ovarian cancer cells. Vandetanib, a clinical approved RET inhibitor, inhibits the cell viability and decreases the activation of RET-MAPK signaling pathways in EOC cells expressing oncogenic RET mutants.

Conclusions

The discovery of RET pathogenic variants in the EOC patients, suggests a previously underestimated role for RET in EOC tumorigenesis. The identification of the gain-of-function RET mutations in EOC highlights the potential use of RET in targeted therapy to treat ovarian cancer patients.

Combination of weekly topotecan and gemcitabine as a salvage treatment in patients with recurrent ovarian cancer: a phase I study

BACKGROUND

Evaluation of safety of the weekly intravenous gemcitabine/topotecan combination as salvage treatment in patients with recurrent epithelial ovarian cancer.

METHODS

Twenty-four women with histologically-proven relapsed ovarian cancer (ROC) were enrolled in the study. Topotecan (1.75 mg/m2 IV) along with escalated doses of gemcitabine (starting dose 700 mg/m2 with increments of 100 mg/m2) were administered on days 1, 8, and 15 every 28 days. The maximum tolerated dose (MTD) and the dose-limiting toxicity of the combination were evaluated at the first cycle.

RESULTS

Twenty-four ROC patients were enrolled in six dose-levels. Most patients had high-grade serous metastatic ovarian cancer (41.7%) and performance status score of 0-1 (95.8%). For 12 patients (50%) treatment was 2nd line and for 12 >2nd line. Eighty-eight cycles were administered with a median of three cycles per patient. The MTD was not reached and grade 3-4 (3.4% and 2.3% of cycles, respectively) neutropenia and grade 4 (3.4% of cycles) thrombocytopenia were the main adverse events. There was no case of febrile neutropenia. Non-hematologic toxicity was mild with grade 2 fatigue being the most frequent complain. The recommended MTD doses of the combination were topotecan 1.75 mg/m2 and gemcitabine 1200 mg/m2 on days 1, 8, and 15 every 28 days. Two complete (8.3%) and three (12.5%) partial responses were achieved (ORR: 20.8%).

CONCLUSIONS

The weekly administration of gemcitabine/topotecan regimen in patients with pretreated metastatic ovarian cancer is an active chemotherapy combination, even in heavily pretreated patients, with a manageable toxicity profile which merits further investigation.

Leptin Regulation of Cancer Stem Cells in Breast and Gynecologic Cancer

It is well established that obesity increases the incidence and worsens the prognosis of women's cancer. For breast cancer, women with obesity exhibit more than a twofold increase in the odds of being diagnosed with cancer, with a greater risk of advanced stage at diagnosis, and ≤40% greater risk of recurrence and death than their normal-weight counterparts. These findings are similar in gynecologic cancers, where women who are obese with a body mass index (BMI) >40 kg/m2 have up to six times greater risk of developing endometrial cancer and a 9.2% increase in mortality with every 10% increase in BMI. Likewise, patients with obesity exhibit a twofold higher risk of premenopausal ovarian cancer, and patients who are obese with advanced stage ovarian cancer have shown a shorter time to recurrence and poorer overall survival. Obesity is accompanied by changes in expression of adipose factors that act on local tissues and systemically. Once obesity was recognized as a factor in cancer incidence and progression, the adipose cytokine (adipokine) leptin became the focus of intense investigation as a putative link, with nearly 3000 publications on the topic. Leptin has been shown to increase cell proliferation, inhibit apoptosis, promote angiogenesis, and increase therapeutic resistance. These characteristics are associated with a subset of cells in both liquid and solid tumors known as cancer stem cells (CSCs), or tumor initiating cells. We will review the literature discussing leptin's role in breast and gynecologic cancer, focusing on its role in CSCs, and consider goals for targeting future therapy in this arena to disrupt tumor initiation and progression in women's cancer.

miR200-regulated CXCL12β promotes fibroblast heterogeneity and immunosuppression in ovarian cancers

High-grade serous ovarian cancers (HGSOC) have been subdivided into molecular subtypes. The mesenchymal HGSOC subgroup, defined by stromal-related gene signatures, is invariably associated with poor patient survival. We demonstrate that stroma exerts a key function in mesenchymal HGSOC. We highlight stromal heterogeneity in HGSOC by identifying four subsets of carcinoma-associated fibroblasts (CAF-S1-4). Mesenchymal HGSOC show high content in CAF-S1 fibroblasts, which exhibit immunosuppressive functions by increasing attraction, survival, and differentiation of CD25⁺FOXP3⁺ T lymphocytes. The beta isoform of the CXCL12 chemokine (CXCL12β) specifically accumulates in the immunosuppressive CAF-S1 subset through a miR-141/200a dependent-mechanism. Moreover, CXCL12β expression in CAF-S1 cells plays a crucial role in CAF-S1 immunosuppressive activity and is a reliable prognosis factor in HGSOC, in contrast to CXCL12α. Thus, our data highlight the differential regulation of the CXCL12α and CXCL12β isoforms in HGSOC, and reveal a CXCL12β-associated stromal heterogeneity and immunosuppressive environment in mesenchymal HGSOC.

PARP inhibitors as potential therapeutic agents for various cancers: focus on niraparib and its first global approval for maintenance therapy of gynecologic cancers

Poly (ADP-ribose) polymerases (PARPs) are an important family of nucleoproteins highly implicated in DNA damage repair. Among the PARP families, the most studied are PARP1, PARP2 and PARP 3. PARP1 is found to be the most abundant nuclear enzyme under the PARP series. These enzymes are primarily involved in base excision repair as one of the major single strand break (SSB) repair mechanisms. Being double stranded, DNA engages itself in reparation of a sub-lethal SSB with the aid of PARP. Moreover, by having a sister chromatid, DNA can also repair double strand breaks with either error-free homologous recombination or error-prone non-homologous end-joining. For effective homologous recombination repair, DNA requires functional heterozygous breast cancer genes (BRCA) which encode BRCA1/2. Currently, the development of PARP inhibitors has been one of the promising breakthroughs for cancer chemotherapy. In March 2017, the United States Food and Drug Administration (FDA) approved niraparib for maintenance therapy of recurrent gynecologic cancers (epithelial ovarian, primary peritoneal and fallopian tube carcinomas) which are sensitive to previous platinum based chemotherapy irrespective of BRCA mutation and homologous recombination deficiency status. It is the third drug in this class to receive FDA approval, following olaparib and rucaparib and is the first global approval for maintenance therapy of the aforementioned cancers. Niraparib preferentially blocks both PARP1 and PARP2 enzymes. The daily tolerated dose of niraparib is 300 mg, above which dose limiting grade 3 and 4 toxicities were observed. In combination with humanized antibody, pembrolizumab, it is also under investigation for those patients who have triple negative breast cancer. By and large, there are several clinical trials that are underway investigating clinical efficacy and safety, as well as other pharmacokinetic and pharmacodynamic profiles of this drug for various malignancies.

Bringing new medicines to women with epithelial ovarian cancer: what is the unmet medical need?

Background

Therapy for advanced epithelial ovarian cancer (OC) includes first line platinum/taxane-containing chemotherapy and re-treatment with platinum-containing regimens for disease recurrence in patients likely to respond again. Single-agent, non-platinum, cytotoxic agents are commonly used to treat patients resistant to platinum retreatment, but these agents are associated with dose-limiting toxicities and response rates below 20%.

Main body

Recent advances have led to novel targeted treatments for recurrent OC that offer opportunities to improve response rates and prolong progression-free intervals. However, they also add complexity to the process of selecting treatment for individual patients at different stages of the disease process. Advanced and recurrent OC is rarely cured. Multiple lines of platinum combinations, and nonplatinum chemotherapeutics eventually fail to achieve clinical benefit, thus other active and tolerable systemic therapies are needed. Consequently, the US Food and Drug Administration has created a mechanism for “accelerated approval” of new medicines in situations of high unmet medical need.

Conclusion

We review the clinical implications of recent key clinical studies in these settings and outline the path forward for study design and approval of novel therapeutics to treat recurrent OC.

Rucaparib: the past, present, and future of a newly approved PARP inhibitor for ovarian cancer

Rucaparib camsylate (CO-338, AG-014699, PF-01367338) is a potent PARP-1, PARP-2, and PARP-3 inhibitor. Phase I and II studies demonstrated clinical efficacy in both BRCA-mutated (inclusive of germline and somatic) ovarian tumors and ovarian tumors with homologous recombination deficiency (HRD) loss of heterozygosity (LOH). Rucaparib has received the US Food and Drug Administration (FDA) approval for patients with deleterious BRCA mutation (germline and/or somatic)-associated advanced ovarian cancer who have been treated with two or more chemotherapies. There is evidence to suggest that rucaparib has clinical efficacy against ovarian tumors with high HRD-LOH. Rucaparib's companion diagnostic FoundationFocus™ CDx BRCA test is the first FDA-approved next-generation sequencing-based companion diagnostic test designed to identify patients likely to respond to rucaparib. This article reviews the mechanisms of action, safety, approval, and indications for use of the PARP inhibitor rucaparib as well as future trials and use of rucaparib's companion diagnostic test.

PARP inhibition and gynecologic malignancies: A review of current literature and on-going trials

The poly (ADP-ribose) polymerase (PARP) family of enzymes is important in several DNA repair pathways. Drugs that inhibit these enzymes have been investigated in many types of cancer, but their application in the treatment of gynecologic malignancies has rapidly evolved - as manifested by the 2014 FDA approval for olaparib in the treatment of recurrent ovarian cancer associated with a germline BRCA mutation (gBRCA). In efforts to broaden their efficacy, current clinical trials have demonstrated benefit of olaparib, and other PARP inhibitors (PARPi), as single agents and in combination with cytotoxic chemotherapy and biologic agents, in wide ranging populations. Although the majority of data for PARPi in gynecologic malignancies has been specifically regarding ovarian cancer, their role in the treatment of uterine and cervical cancer is currently being investigated. This review will serve as a synopsis of seminal trials to date, summarize the breadth of clinical application in on-going studies, query how these results may change future practice, and reflect on questions yet to be answered.