Novel therapeutics: response and resistance in ovarian cancer

In ovarian cancer maraviroc potentiates the antitumoral activity and further inhibits the formation of a tumor-promoting microenvironment by trabectedin

Ovarian cancer (OC) is the fifth most frequent cause of cancer-related death in women. Chemotherapy agent trabectedin, affecting cancer cells and tumor microenvironment, has been approved for the treatment of relapsed platinum-sensitive OC patients. CCR5-antagonist maraviroc inhibits tumor growth, metastasis, and enhances the antitumoral activity of DNA-damaging drugs. Here, we found that OC cells expressed CCR5 receptor but did not secret CCR5-ligands. Maraviroc treatment did not affect OC cell viability, but strongly potentiated the antiproliferative activity, apoptosis induction, cell cycle blockage, DNA damage, and ROS formation by trabectedin. In A2780cis cisplatin-resistant cells, the cross-resistance to trabectedin was overcame by the combination with maraviroc. Maraviroc enhanced trabectedin cytotoxicity in OC 3Dimensional spheroids and THP-1-monocytes. Both maraviroc and trabectedin interact with drug efflux pump MDR1/P-gp, overexpressed in recurrent OC patients. Maraviroc increased trabectedin intracellular accumulation and the MDR1-inhibitor verapamil, like maraviroc, increased trabectedin cytotoxicity. In OC tumor xenografts the combination with maraviroc further reduced tumor growth, angiogenesis, and monocyte infiltration by trabectedin. In conclusion, this study offers a preclinical rationale for the use of maraviroc as new option to improve trabectedin activity in relapsed chemoresistant OC patients.

Novel players in the development of chemoresistance in ovarian cancer: ovarian cancer stem cells, non-coding RNA and nuclear receptors

Ovarian cancer (OC) ranks as the fifth leading factor for female mortality globally, with a substantial burden of new cases and mortality recorded annually. Survival rates vary significantly based on the stage of diagnosis, with advanced stages posing significant challenges to treatment. OC is primarily categorized as epithelial, constituting approximately 90% of cases, and correct staging is essential for tailored treatment. The debulking followed by chemotherapy is the prevailing treatment, involving platinum-based drugs in combination with taxanes. However, the efficacy of chemotherapy is hindered by the development of chemoresistance, both acquired during treatment (acquired chemoresistance) and intrinsic to the patient (intrinsic chemoresistance). The emergence of chemoresistance leads to increased mortality rates, with many advanced patients experiencing disease relapse shortly after initial treatment. This review delves into the multifactorial nature of chemoresistance in OC, addressing mechanisms involving transport systems, apoptosis, DNA repair, and ovarian cancer stem cells (OCSCs). While previous research has identified genes associated with these mechanisms, the regulatory roles of non-coding RNA (ncRNA) and nuclear receptors in modulating gene expression to confer chemoresistance have remained poorly understood and underexplored. This comprehensive review aims to shed light on the genes linked to different chemoresistance mechanisms in OC and their intricate regulation by ncRNA and nuclear receptors. Specifically, we examine how these molecular players influence the chemoresistance mechanism. By exploring the interplay between these factors and gene expression regulation, this review seeks to provide a comprehensive mechanism driving chemoresistance in OC.

Therapeutic strategies targeting folate receptor α for ovarian cancer

Epithelial ovarian cancer (EOC) is the deadliest gynecological cancer, and presents a major clinical challenge due to limited treatment options. Folate receptor alpha (FRα), encoded by the FOLR1 gene, is an attractive therapeutically target due to its prevalent and high expression in EOC cells. Recent basic and translational studies have explored several modalities, such as antibody-drug conjugate (ADC), monoclonal antibodies, small molecules, and folate-drug conjugate, to exploit FRα for EOC treatment. In this review, we summarize the function of FRα, and clinical efficacies of various FRα-based therapeutics. We highlight mirvetuximab soravtansine (MIRV), or Elahere (ImmunoGen), the first FRα-targeting ADC approved by the FDA to treat platinum-resistant ovarian cancer. We discuss potential mechanisms and management of ocular adverse events associated with MIRV administration.

Targeting ovarian cancer stem cells: a new way out

Ovarian cancer (OC) is the most lethal gynecological malignancy due to tumor heterogeneity, the lack of reliable early diagnosis methods and the high incidence of chemoresistant recurrent disease. Although there are developments in chemotherapies and surgical techniques to improve the overall survival of OC patients, the 5-year survival of advanced OC patients is still low. To improve the prognosis of OC patients, it is important to search for novel therapeutic approaches. Cancer stem cells (CSCs) are a subpopulation of tumor cells that participate in tumor growth, metastasis and chemoresistance. It is important to study the role of CSCs in a highly heterogeneous disease such as OC, which may be significant to a better understanding of the oncogenetic and metastatic pathways of the disease and to develop novel strategies against its progression and platinum resistance. Here, we summarized the current findings about targeting methods against ovarian cancer stem cells, including related signaling pathways, markers and drugs, to better manage OC patients using CSC-based therapeutic strategies.

A Subset of Secreted Proteins in Ascites Can Predict Platinum-Free Interval in Ovarian Cancer

The time between the last cycle of chemotherapy and recurrence, the platinum-free interval (PFI), predicts overall survival in high-grade serous ovarian cancer (HGSOC). To identify secreted proteins associated with a shorter PFI, we utilized machine learning to predict the PFI from ascites composition. Ascites from stage III/IV HGSOC patients treated with neoadjuvant chemotherapy (NACT) or primary debulking surgery (PDS) were screened for secreted proteins and Lasso regression models were built to predict the PFI. Through regularization techniques, the number of analytes used in each model was reduced; to minimize overfitting, we utilized an analysis of model robustness. This resulted in models with 26 analytes and a root-mean-square error (RMSE) of 19 days for the NACT cohort and 16 analytes and an RMSE of 7 days for the PDS cohort. High concentrations of MMP-2 and EMMPRIN correlated with a shorter PFI in the NACT patients, whereas high concentrations of uPA Urokinase and MMP-3 correlated with a shorter PFI in PDS patients. Our results suggest that the analysis of ascites may be useful for outcome prediction and identified factors in the tumor microenvironment that may lead to worse outcomes. Our approach to tuning for model stability, rather than only model accuracy, may be applicable to other biomarker discovery tasks.

Molecular subtypes, clinical significance, and tumor immune landscape of angiogenesis-related genes in ovarian cancer

Angiogenesis is a physiological process, where new blood vessels are formed from pre-existing vessels through the mechanism called sprouting. It plays a significant role in supporting tumor growth and is expected to provide novel therapeutic ideas for treating tumors that are resistant to conventional therapies. We investigated the expression pattern of angiogenesis-related genes (ARGs) in ovarian cancer (OV) from public databases, in which the patients could be classified into two differential ARG clusters. It was observed that patients in ARGcluster B would have a better prognosis but lower immune cell infiltration levels in the tumor microenvironment. Then ARG score was computed based on differentially expressed genes via cox analysis, which exhibited a strong correlation to copy number variation, immunophenoscore, tumor mutation load, and chemosensitivity. In addition, according to the median risk score, patients were separated into two risk subgroups, of which the low-risk group had a better prognosis, increased immunogenicity, and stronger immunotherapy efficacy. Furthermore, we constructed a prognostic nomogram and demonstrated its predictive value. These findings help us better understand the role of ARGs in OV and offer new perspectives for clinical prognosis and personalized treatment.

Knockdown of ENTPD5 inhibits tumor metastasis and growth via regulating the GRP78/p-eIF-2α/CHOP pathway in serous ovarian cancer

Background

Dysregulation of Ectonucleoside Triphospahate Diphosphohydrolase 5 (ENTPD5) in tumors might be associated with tumor progression, while the role of ENTPD5 in the growth and metastasis of serous ovarian cancer (SOC) is still unclear.

Methods

ENTPD5 expression patterns in ovarian cancer tissues were analyzed by qRT-PCR and immunohistochemistry assay (IHC). Two SOC cell lines, SKOV3 and OVCAR8, were stably transfected with lentivirus to build knockdown and overexpression cell lines. Clone formation assay, collagen gel droplet culture technology, wound healing assay and flow cytometry were used to assess the migration and growth traits of SOC cells. Expression levels of ENTPD5, glucose regulated protein 78 (GRP78), eukaryotic translation initiation factor 2 alpha (eIF-2α), phosphorylated -eIF-2α and, C/EBP homologous protein (CHOP) in SOC cells were detected by Western blot.

Results

Compared to fallopian tube tissues, the expression of ENTPD5 was significantly higher in tumor tissues obtained from SOC patients, and positively correlated with clinical stage and metastasis. ENTPD5 knockdown robustly inhibited cell proliferation, migration, whereas ENTPD5 overexpression elicited the opposite effect on SOC cells. ENTPD5 knockdown arrested cell cycle in G0/G1 phase and increased apoptosis. Importantly, ENTPD5 knockdown was associated with significantly decreased protein levels for GRP78, CHOP, and p-eIF-2α, suggesting possible involvement of ENTPD5 in endoplasmic reticulum stress (ERS).

Conclusions

Our study demonstrates that ENTPD5 knockdown inhibited SOC cell proliferation, migration and restrained the activation of the GRP78/p-eIF-2α/CHOP pathway, which provides a potentially effective therapeutic target for the treatment of SOC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-022-00996-0.

Comprehensive Analysis of the Tumor Microenvironment and Ferroptosis-Related Genes Predict Prognosis with Ovarian Cancer

The early diagnosis of ovarian cancer (OC) is critical to improve the prognosis and prevent recurrence of patients. Nevertheless, there is still a lack of factors which can accurately predict it. In this study, we focused on the interaction of immune infiltration and ferroptosis and selected the ESTIMATE algorithm and 15 ferroptosis-related genes (FRGs) to construct a novel E-FRG scoring model for predicting overall survival of OC patients. The gene expression and corresponding clinical characteristics were obtained from the TCGA dataset (n = 375), GSE18520 (n = 53), and GSE32062 (n = 260). A total of 15 FRGs derived from FerrDb with the immune score and stromal score were identified in the prognostic model by using least absolute shrinkage and selection operator (LASSO)–penalized COX regression analysis. The Kaplan–Meier survival analysis and time-dependent ROC curves performed a powerful prognostic ability of the E-FRG model via multi-validation. Gene Set Enrichment Analysis and Gene Set Variation Analysis elucidate multiple potential pathways between the high and low E-FRG score group. Finally, the proteins of different genes in the model were verified in drug-resistant and non–drug-resistant tumor tissues. The results of this research provide new prospects in the role of immune infiltration and ferroptosis as a helpful tool to predict the outcome of OC patients.

MicroRNA miR-30a inhibits cisplatin resistance in ovarian cancer cells through autophagy

We study whether microRNA miR-30a inhibits the autophagy through transforming growth factor (TGF)-β/Smad4 to generate cisplatin (DDP) resistance in ovarian cancer cells. The expression of miR-30a, Smad4, and TGF-β was detected in the serum of ovarian cancer patients and DDP-resistant cell lines (A2780) by quantitative real-time polymerase chain reaction (qRT-PCR). Computational search and western blotting were used to demonstrate the downstream target of miR-30a in ovarian cancer cells. Cell viability was measured with CCK8 assay. Apoptosis and autophagy of ovarian cancer cells were analyzed by flow cytometry and transmission electron microscopy, and the expressions of Beclin1 and LC3II protein were detected by western blotting. Expression of miR-30a was significantly decreased, while expressions of TGF-β and Smad4 mRNA were increased in serum of ovarian cancer patients after DDP chemotherapy as well as in DDP-resistant cells. Activation of autophagy contributed to DDP-resistance cells. Moreover, Bioinformatics software predicted Smad4 to be a target of miR-30a. Overexpression of miR-30a decreased the expression of Smad4 and TGF-β. Additionally, miR-30a-overexpressing inhibited DDP-induce autophagy and promoted DDP-resistant cell apoptosis. In conclusion, miR-30a mediates DDP resistance in ovarian cancer by inhibiting autophagy via the TGF-β/Smad4 pathway.

G-quadruplex binding properties of a potent PARP-1 inhibitor derived from 7-azaindole-1-carboxamide

Poly ADP-ribose polymerases (PARP) are key proteins involved in DNA repair, maintenance as well as regulation of programmed cell death. For this reason they are important therapeutic targets for cancer treatment. Recent studies have revealed a close interplay between PARP1 recruitment and G-quadruplex stabilization, showing that PARP enzymes are activated upon treatment with a G4 ligand. In this work the DNA binding properties of a PARP-1 inhibitor derived from 7-azaindole-1-carboxamide, (2-[6-(4-pyrrolidin-1-ylmethyl-phenyl)-pyrrolo[2,3-b]pyridin-1-yl]-acetamide, compound 1) with model duplex and quadruplex DNA oligomers were studied by NMR, CD, fluorescence and molecular modelling. We provide evidence that compound 1 is a strong G-quadruplex binder. In addition we provide molecular details of the interaction of compound 1 with two model G-quadruplex structures: the single repeat of human telomeres, d(TTAGGGT)₄, and the c-MYC promoter Pu22 sequence. The formation of defined and strong complexes with G-quadruplex models suggests a dual G4 stabilization/PARP inhibition mechanism of action for compound 1 and provides the molecular bases of its therapeutic potential.

Nanoparticle delivery systems to combat drug resistance in ovarian cancer

Due to the lack of early symptoms and difficulty of accurate diagnosis, ovarian cancer is the most lethal gynecological cancer faced by women. First-line therapy includes a combination of tumor resection surgery and chemotherapy regimen. However, treatment becomes more complex upon recurrence due to development of drug resistance. Drug resistance has been linked to many mechanisms, including efflux transporters, apoptosis dysregulation, autophagy, cancer stem cells, epigenetics, and the epithelial-mesenchymal transition. Thus, developing and choosing effective therapies is exceptionally complex. There is a need for increased specificity and efficacy in therapies for drug-resistant ovarian cancer, and research in targeted nanoparticle delivery systems aims to fulfill this challenge. Although recent research has focused on targeted nanoparticle-based therapies, few of these therapies have been clinically translated. In this review, non-viral nanoparticle delivery systems developed to overcome drug-resistance in ovarian cancer were analyzed, including their structural components, surface modifications, and drug-resistance targeted mechanisms.

Ovarian cancer predisposition beyond BRCA1 and BRCA2 genes

Several genes associated with hereditary ovarian cancer have been discovered as a result of the work done with next generation sequencing. It is estimated that approximately 23% of ovarian carcinomas have a hereditary predisposition. The most common hereditary condition is represented by germline mutations in BRCA1 or BRCA2 genes that account for 20-25% of high grade serous ovarian cancer. A number of other hereditary ovarian cancers are associated with different genes, with a crucial role in the DNA damage response pathway, such as the mismatch repair genes in Lynch syndrome, TP53 in Li-Fraumeni syndrome, STK11 in Peutz-Jeghers syndrome, CHEK2, RAD51, BRIP1, and PALB2. The goal of this manuscript is to summarize the published data regarding the molecular pathways involved in the pathogenesis of non-BRCA related hereditary ovarian cancer and to provide a tool that might be useful in discussing risk assessment, genetic testing, prevention strategies, as well as clinical and therapeutic implications for patients with ovarian cancer.