Reversing platinum resistance in ovarian cancer multicellular spheroids by targeting Bcl-2

ACSM3 Suppresses Ovarian Cancer Progression by Inactivating the IFN-γ/JAK/STAT3 Signaling Pathway

This study aimed to investigate the role of Acyl-CoA medium-chain synthetase 3 (ACSM3) in ovarian cancer (OC) progression. ACSM3 expression in OC tissues and cells is detected by real-time quantitative polymerase chain reaction, immunohistochemistry, or western blot. The influences of ACSM3 on OC progression are assessed in vitro and in vivo experiments. Gene set enrichment analysis is performed to find significantly enriched pathways related to ACSM3. In this study, ACSM3 expression in OC tissues and cells is downregulated. ACSM3 inhibited tumor growth in vivo. Knockdown of ACSM3 promoted cell proliferation, migration, and invasion, inhibited cell apoptosis, and activated JAK/STAT3 signaling pathway in SKOV3 cells, while overexpression of ACSM3 in A2780 cells led to the opposite results. Moreover, treatment with interferon-gamma (IFN-γ) in A2780 cells reversed the effects of ACSM3 on cell proliferation, migration, invasion, and apoptosis, but IFN-γ further enhanced the effects of ACSM3 knockdown on SKOV3 cell proliferation, migration, invasion, and apoptosis. In conclusion, ACSM3 inhibited OC cell proliferation, migration, and invasion, and promoted cell apoptosis by suppressing the IFN-γ/JAK/STAT3 signaling pathway, which might provide a promising therapeutic target for OC treatment.

Omics Investigations of Prostate Cancer Cells Exposed to Simulated Microgravity Conditions

Prostate cancer (PC) is the most diagnosed cancer in males across the globe. Following the formation of metastasis, PC is linked to a notable decline in both prognosis and survival rates. Three-dimensional multicellular spheroids (MCSs) of a prostate adenocarcinoma cell line were generated in a three-day simulated microgravity environment (s-µg) to serve as a model for metastasis and to derive transcriptional and epigenetic PC candidates from molecular biological changes. With an FDR of 10-3, we detected the most differentially expressed genes in the two comparisons' adherent cells (AD) to MCSs (N = 751 genes) and 1g control cells to MCSs (N = 662 genes). In these two comparisons, genes related to cell cycle, angiogenesis, cell adhesion, and extracellular space were consistently found to be significantly enriched in GO annotations. Furthermore, at a 5% FDR significance level, we were able to identify 11,090 genome-wide differentially methylated positions (DMPs) and one differentially methylated region in the SRMS gene in the 1g vs. AD comparison, as well as an additional 10,797 DMPs in the 1g vs. MCSs comparison. Finally, we identified five s-µg-related positive enrichments of transcription factor binding sites for AR, IRF1, IRF2, STAT1, STAT2, and FOXJ3 close to the DMPs.

Drug resistance biomarkers in ovarian cancer: a bibliometric study from 2017 to 2022

Background

Late diagnosis and patient relapse, mainly due to chemoresistance, are the key reasons for the high mortality rate of ovarian cancer patients. Hence, the search for biomarkers of high predictive value within the phenomenon of chemoresistance is vital. This study performs a bibliometric analysis of the scientific literature concerning biomarkers of drug resistance in ovarian cancer, considering the period from 2017 to 2022.

Methods

The terms "drug resistance biomarker" and "ovarian cancer" were linked by the Boolean operator "AND". The search was done in PubMed, selecting documents published over the last 5 years (2017-2022), which were analyzed with the open-source tool Bibliometrix developed in the R package. The language of the publications was restricted to English. Several types of papers such as case reports, clinical trials, comparative studies, and original articles were considered.

Results

A total of 335 scientific articles were analyzed. The United States and China were the leading contributors and established the largest number of scientific collaborations. The Huazhong University of Science and Technology and the University of Texas MD Anderson Cancer Center were the most influential institutions. The Journal of Ovarian Research, International Journal of Molecular Science, and Scientific Reports are among the most relevant journals. The study identified high-profile, relevant thematic niches and important descriptors that indicate topics of interest, including studies on women, cell lines, solid tumors, and gene expression regulation. As well as studies involving middle-aged and adult participants, and those focusing on prognosis evaluation. Descriptors such as "drug resistance," "neoplasm," "genetics," "biomarker," "gene expression profile," and "drug therapy" would indicate new research trends. In addition, we propose that BCL-2, CHRF, SNAIL, miR-363, iASPP, ALDH1, Fzd7, and EZH2 are potential biomarkers of drug resistance.

Conclusions

This paper contributes to the global analysis of the scientific investigation related to drug resistance biomarkers in ovarian cancer to facilitate further studies and collaborative networks, which may lead to future improvements in therapy for this lethal disease.

Overview of BH3 mimetics in ovarian cancer

Ovarian carcinoma is the leading cause of gynecological cancer-related death, still with a dismal five-year prognosis, mainly due to late diagnosis and the emergence of resistance to cytotoxic and targeted agents. Bcl-2 family proteins have a key role in apoptosis and are associated with tumor development/progression and response to therapy in different cancer types, including ovarian carcinoma. In tumors, evasion of apoptosis is a possible mechanism of resistance to therapy. BH3 mimetics are small molecules that occupy the hydrophobic pocket on pro-survival proteins, allowing the induction of apoptosis, and are currently under study as single agents and/or in combination with cytotoxic and targeted agents in solid tumors. Here, we discuss recent advances in targeting anti-apoptotic proteins of the Bcl-2 family for the treatment of ovarian cancer, focusing on BH3 mimetics, and how these approaches could potentially offer an alternative/complementary way to treat patients and overcome or delay resistance to current treatments.

Enhancing precision medicine: a nomogram for predicting platinum resistance in epithelial ovarian cancer

BACKGROUND

This study aimed to develop a novel nomogram that can accurately estimate platinum resistance to enhance precision medicine in epithelial ovarian cancer(EOC).

METHODS

EOC patients who received primary therapy at the General Hospital of Ningxia Medical University between January 31, 2019, and June 30, 2021 were included. The LASSO analysis was utilized to screen the variables which contained clinical features and platinum-resistance gene immunohistochemistry scores. A nomogram was created after the logistic regression analysis to develop the prediction model. The consistency index (C-index), calibration curve, receiver operating characteristic (ROC) curve, and decision curve analysis (DCA) were used to assess the nomogram's performance.

RESULTS

The logistic regression analysis created a prediction model based on 11 factors filtered down by LASSO regression. As predictors, the immunohistochemical scores of CXLC1, CXCL2, IL6, ABCC1, LRP, BCL2, vascular tumor thrombus, ascites cancer cells, maximum tumor diameter, neoadjuvant chemotherapy, and HE4 were employed. The C-index of the nomogram was found to be 0.975. The nomogram's specificity is 95.35% and its sensitivity, with a cut-off value of 165.6, is 92.59%, as seen by the ROC curve. After the nomogram was externally validated in the test cohort, the coincidence rate was determined to be 84%, and the ROC curve indicated that the nomogram's AUC was 0.949.

CONCLUSION

A nomogram containing clinical characteristics and platinum gene IHC scores was developed and validated to predict the risk of EOC platinum resistance.

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.

Toxicity and autophagy effects of fluorinated cycloplatinated(II) complex bearing dppm ligand on cancer cells in in-vitro culture and in-silico prediction

Toxicity and autophagy effects of a new complex of platinum II (CPC) were evaluated on HeLa cells cultured on a PCL/gelatin electrospinning scaffold. HeLa cells were treated with CPC on the first, third, and fifth days and the concentration of IC₅₀ was determined. The autophagic and apoptotic effects of CPC were examined by MTT assay, Acridine Orange, Giemsa, DAPI, MDC, real-time PCR, Western blot testing, and molecular docking. The cell viability was obtained on days 1, 3, and 5 as much as 50, 7.28, and 19%, respectively with a concentration of IC₅₀ (100μM) of CPC. The staining results indicated that the treatment of HeLa cells with CPC had antitumor and autophagic effects. Results of RT-PCR showed that the expression of BAX, BAD, P53, and LC3 genes was significantly increased in the sample treated with IC₅₀ concentration compared to the control sample whereas the expression of BCL2, mTOR, and ACT genes in cells was significantly decreased compared to the control group. Also, these results were confirmed by Western blotting. The data indicated the induction of apoptotic death and autophagy in the studied cells. The new compound of CPC has antitumor effects.

Mechanisms of Drug Resistance in Ovarian Cancer and Associated Gene Targets

In the United States, over 100,000 women are diagnosed with a gynecologic malignancy every year, with ovarian cancer being the most lethal. One of the hallmark characteristics of ovarian cancer is the development of resistance to chemotherapeutics. While the exact mechanisms of chemoresistance are poorly understood, it is known that changes at the cellular and molecular level make chemoresistance challenging to treat. Improved therapeutic options are needed to target these changes at the molecular level. Using a precision medicine approach, such as gene therapy, genes can be specifically exploited to resensitize tumors to therapeutics. This review highlights traditional and novel gene targets that can be used to develop new and improved targeted therapies, from drug efflux proteins to ovarian cancer stem cells. The review also addresses the clinical relevance and landscape of the discussed gene targets.

Metastatic Voyage of Ovarian Cancer Cells in Ascites with the Assistance of Various Cellular Components

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy and has a unique metastatic route using ascites, known as the transcoelomic root. However, studies on ascites and contained cellular components have not yet been sufficiently clarified. In this review, we focus on the significance of accumulating ascites, contained EOC cells in the form of spheroids, and interaction with non-malignant host cells. To become resistant against anoikis, EOC cells form spheroids in ascites, where epithelial-to-mesenchymal transition stimulated by transforming growth factor-β can be a key pathway. As spheroids form, EOC cells are also gaining the ability to attach and invade the peritoneum to induce intraperitoneal metastasis, as well as resistance to conventional chemotherapy. Recently, accumulating evidence suggests that EOC spheroids in ascites are composed of not only cancer cells, but also non-malignant cells existing with higher abundance than EOC cells in ascites, including macrophages, mesothelial cells, and lymphocytes. Moreover, hetero-cellular spheroids are demonstrated to form more aggregated spheroids and have higher adhesion ability for the mesothelial layer. To improve the poor prognosis, we need to elucidate the mechanisms of spheroid formation and interactions with non-malignant cells in ascites that are a unique tumor microenvironment for EOC.

Patient-Derived Ovarian Cancer Spheroids Rely on PI3K-AKT Signaling Addiction for Cancer Stemness and Chemoresistance

Simple Summary

Epithelial ovarian cancer (EOC) is the most fatal gynecological cancer with poor survival rates and high mortality. EOC patients respond to standard platinum-based chemotherapy in the beginning, but relapse often due to chemoresistance. Ovarian cancer cells disseminate from the ovarian tumors and spread within the abdomen, where ascites fluid supports the growth and transition. Malignant ascites is present in a third of patients at diagnosis and is considered as a major source of chemoresistance, recurrence, poor survival, and mortality. Malignant ascites is a complex fluid that contains a pro-tumorigenic environment with disseminated cancer cells in 3D spheroids form. In this study, we established an ovarian cancer cell line and identified that 3D spheroids develop from the 2D monolayer, and the platinum-resistant phenotype develops due to the aberrant PI3K-AKT signaling in tumor cells. Furthermore, when we used a combinatorial approach of cisplatin with LY-294002 (a PI3K-AKT dual kinase inhibitor) to treat the cisplatin version of both MCW-OV-SL-3 and A-2780 cell lines, it prevented the 3D spheroid formation ability and also sensitized the cells for cisplatin. In brief, our results provided evidence to advance therapeutic approaches to treat cisplatin resistance in ovarian cancer patients.

Abstract

Ovarian cancer is the most lethal gynecological malignancy among women worldwide and is characterized by aggressiveness, cancer stemness, and frequent relapse due to resistance to platinum-based therapy. Ovarian cancer cells metastasize through ascites fluid as 3D spheroids which are more resistant to apoptosis and chemotherapeutic agents. However, the precise mechanism as an oncogenic addiction that makes 3D spheroids resistant to apoptosis and chemotherapeutic agents is not understood. To study the signaling addiction mechanism that occurs during cancer progression in patients, we developed an endometrioid subtype ovarian cancer cell line named ‘MCW-OV-SL-3’ from the ovary of a 70-year-old patient with stage 1A endometrioid adenocarcinoma of the ovary. We found that the cell line MCW-OV-SL-3 exhibits interstitial duplication of 1q (q21–q42), where this duplication resulted in high expression of the PIK3C2B gene and aberrant activation of PI3K-AKT-ERK signaling. Using short tandem repeat (STR) analysis, we demonstrated that the cell line exhibits a unique genetic identity compared to existing ovarian cancer cell lines. Notably, the MCW-OV-SL-3 cell line was able to form 3D spheroids spontaneously, which is an inherent property of tumor cells when plated on cell culture dishes. Importantly, the tumor spheroids derived from the MCW-OV-SL-3 cell line expressed high levels of c-Kit, PROM1, ZEB1, SNAI, VIM, and Twist1 compared to 2D monolayer cells. We also observed that the hyperactivation of ERK and PI3K/AKT signaling in these cancer cells resulted in resistance to cisplatin. In summary, the MCW-OV-SL3 endometrioid cell line is an excellent model to study the mechanism of cancer stemness and chemoresistance in endometrioid ovarian cancer.

Transcending toward Advanced 3D-Cell Culture Modalities: A Review about an Emerging Paradigm in Translational Oncology

Cancer is a disorder characterized by an uncontrollable overgrowth and a fast-moving spread of cells from a localized tissue to multiple organs of the body, reaching a metastatic state. Throughout years, complexity of cancer progression and invasion, high prevalence and incidence, as well as the high rise in treatment failure cases leading to a poor patient prognosis accounted for continuous experimental investigations on animals and cellular models, mainly with 2D- and 3D-cell culture. Nowadays, these research models are considered a main asset to reflect the physiological events in many cancer types in terms of cellular characteristics and features, replication and metastatic mechanisms, metabolic pathways, biomarkers expression, and chemotherapeutic agent resistance. In practice, based on research perspective and hypothesis, scientists aim to choose the best model to approach their understanding and to prove their hypothesis. Recently, 3D-cell models are seen to be highly incorporated as a crucial tool for reflecting the true cancer cell microenvironment in pharmacokinetic and pharmacodynamics studies, in addition to the intensity of anticancer drug response in pharmacogenomics trials. Hence, in this review, we shed light on the unique characteristics of 3D cells favoring its promising usage through a comparative approach with other research models, specifically 2D-cell culture. Plus, we will discuss the importance of 3D models as a direct reflector of the intrinsic cancer cell environment with the newest multiple methods and types available for 3D-cells implementation.

Amplification and expression of c-MET correlate with poor prognosis of patients with gastric cancer and upregulate the expression of PDL1

The prognostic significance of c-MET in gastric cancer (GC) remains uncertain. In the present study, we examined the amplification, expression, and the prognostic value of c-MET, human epidermal growth factor receptor 2 (HER2), and programmed cell death 1 ligand 1 (PDL1), together with the correlations among them in a large cohort of Chinese samples. A total of 444 patients were included. The immunohistochemistry (IHC) and the dual-color silver in situ hybridization (SISH) were performed to examine their expression and amplification. Univariate and multivariate analyses were performed by the Cox proportional hazard regression model, and survival curves were estimated by the Kaplan-Meier method. The positivity determined by IHC of c-MET was 24.8%, and the MET amplification rate was 2.3%. The positivity rates of HER2 and PDL1 were 8% and 34.7%, respectively. PDL1 expression had a significantly positive association with c-MET expression. c-MET positivity played a significant prognostic role in disease-free survival (DFS) (P = 0.032). Patients with mesenchymal-epithelial transition (MET) amplification had significantly poorer prognosis on both DFS and overall survival (OS). Subgroup analysis showed that in HER2-negative patients, but not in HER2-positive patients, MET-positive patients had significantly worse DFS (P = 0.000) and OS (P = 0.006). c-MET regulated the expression of PDL1 through an AKT-dependent pathway. c-MET inhibitor enhanced the T-cell killing ability and increased the efficacy of PD1 antibody. c-MET was found to be an independent prognostic factor for DFS of GC patients. A combination of c-MET inhibitors and PD1 antibodies could enhance the killing capacity of T cells, providing a preliminary basis for the clinical research on the same combination in GC treatment.

Theasaponin E1 Inhibits Platinum-Resistant Ovarian Cancer Cells through Activating Apoptosis and Suppressing Angiogenesis

Novel therapeutic strategies for ovarian cancer treatment are in critical need due to the chemoresistance and adverse side effects of platinum-based chemotherapy. Theasaponin E₁ (TSE1) is an oleanane-type saponin from Camellia sinensis seeds. Its apoptosis-inducing, cell cycle arresting and antiangiogenesis activities against platinum-resistant ovarian cancer cells were elucidated in vitro and using the chicken chorioallantoic membrane (CAM) assay. The results showed that TSE1 had more potent cell growth inhibitory effects on ovarian cancer OVCAR-3 and A2780/CP70 cells than cisplatin and was lower in cytotoxicity to normal ovarian IOSE-364 cells. TSE1 significantly induced OVCAR-3 cell apoptosis via the intrinsic and extrinsic apoptotic pathways, slightly arresting cell cycle at the G2/M phase, and obviously inhibited OVCAR-3 cell migration and angiogenesis with reducing the protein secretion and expression of vascular endothelial growth factor (VEGF). Western bolt assay showed that Serine/threonine Kinase (Akt) signaling related proteins including Ataxia telangiectasia mutated kinase (ATM), Phosphatase and tensin homolog (PTEN), Akt, Mammalian target of rapamycin (mTOR), Ribosome S6 protein kinase (p70S6K) and e IF4E-binding protein 1(4E-BP1) were regulated, and Hypoxia inducible factor-1α (HIF-1α) protein expression was decreased by TSE1 in OVCAR-3 cells. Moreover, TSE1 treatment potently downregulated protein expression of the Notch ligands including Delta-like protein 4 (Dll4) and Jagged1, and reduced the protein level of the intracellular domain (NICD) of Notch1. Combination treatment of TSE1 with the Notch1 signaling inhibitor tert-butyl (2S)-2-[[(2S)-2-[[2-(3,5-difluorophenyl)acetyl]amino]propanoyl]amino]-2-phenylacetate (DAPT), or the Akt signaling inhibitor wortmannin, showed a stronger inhibition toward HIF-1α activation compared with single compound treatment. Taken together, TSE1 might be a potential candidate compound for improving platinum-resistant ovarian cancer treatment via Dll4/Jagged1-Notch1-Akt-HIF-1α axis.

Targeting the tumour microenvironment in platinum-resistant ovarian cancer

Ovarian cancer typically presents at an advanced stage, and although the majority of cases initially respond well to platinum-based therapies, chemoresistance almost always occurs leading to a poor long-term prognosis. While various cellular autonomous mechanisms contribute to intrinsic or acquired platinum resistance, the tumour microenvironment (TME) plays a central role in resistance to therapy and disease progression by providing cancer stem cell niches, promoting tumour cell metabolic reprogramming, reducing chemotherapy drug perfusion and promoting an immunosuppressive environment. As such, the TME is an attractive therapeutic target which has been the focus of intense research in recent years. This review provides an overview of the unique ovarian cancer TME and its role in disease progression and therapy resistance, highlighting some of the latest preclinical and clinical data on TME-targeted therapies. In particular, it focuses on strategies targeting cancer-associated fibroblasts, tumour-associated macrophages, cancer stem cells and cancer cell metabolic vulnerabilities.

Small Molecule Targeting of Oxysterol-Binding Protein (OSBP)-Related Protein 4 and OSBP Inhibits Ovarian Cancer Cell Proliferation in Monolayer and Spheroid Cell Models

The development of precision drugs for the selective treatment of ovarian cancer will require targeting proliferative factors selectively expressed in ovarian tumors or targeting unique physiological microenvironments specific for ovarian tumors. Here, we report that oxysterol-binding protein (OSBP)-related protein 4 (ORP4) is a potential druggable precision target in ovarian cancer cells. ORP4 has limited expression in normal tissues and was recently recognized to be a cancer-specific driver of cellular proliferation, including in patient-isolated leukemias. We demonstrate that ORP4 is strongly expressed in a panel of ovarian cancer cell lines. The antiproliferative natural product compound OSW-1 targets ORP4 and OSBP. Our results demonstrate that the OSW-1 compound has high antiproliferative potency in both monolayer and three-dimensional ovarian cancer spheroid models, especially compared to the standard-of-care agents cisplatin and paclitaxel. OSW-1 compound treatment induces a loss of ORP4 expression after 48 h, which is coincident with the cytotoxic effects of OSW-1. The absence of extracellular lipids markedly potentiated the cytotoxicity of OSW-1, which was reversed by addition of extracellular free cholesterol. OSBP, but not ORP4, is reported to transport cholesterol and other lipids between organelles. Our results indicate that the targeting of ORP4 is responsible for the antiproliferative activity of the OSW-1 compound, but that in the absence of exogenously supplied cholesterol, which might be similar to the in vivo ovarian cancer microenvironment, possible OSW-1 targeting of OSBP further potentiates the anticancer activity of the compound. Overall, ORP4 and potentially OSBP are revealed as potential druggable targets for the development of novel treatments for ovarian cancer.

Exploring the Potential of Drug Response Assays for Precision Medicine in Ovarian Cancer

One of the major challenges in the treatment of cancer are differential responses of patients to existing standard of care anti-cancer drugs. These differential responses may, in part, be due to a diverse range of genomic, epigenomic, proteomic, and metabolic alterations among individuals suffering from the same type of cancer. Precision medicine is an emerging approach in cancer therapeutics that takes into account specific molecular alterations, environmental factors as well as lifestyle of individual patients. This approach allows clinicians and researchers to select or predict treatments that would most likely benefit the patient based on their individual tumor characteristics. One class of precision medicine tools are predictive, in vitro drug-response assays designed to test the sensitivity of patient tumor cells to existing or novel therapies. These assays have the potential to rapidly identify the most effective treatments for cancer patients and thus hold great promise in the field of precision medicine. In this review, we have highlighted several drug-response assays developed in ovarian cancer and discussed the current challenges and future prospects of these assays in the clinical management of this disease.

Adaptation of metabolism to multicellular aggregation, hypoxia and obese stromal cell incorporation as potential measure of survival of ovarian metastases

Ovarian metastases exfoliate from the primary tumor and it is thought that aggregation supports their survival in the peritoneal cavity during dissemination but the underlying mechanisms are not clearly identified. We have previously shown that ovarian cancer cells acquire an increasingly glycolytic and metabolic flexible phenotype during progression. In the present study, we investigated how hypoxia, aggregation, and the incorporation of the obese stromal vascular fraction (SVF) affect cellular metabolism and the response to common anti-cancer and anti-diabetic drugs. Our results show a reduction of glucose uptake, lactate secretion, cellular respiration and ATP synthesis in response to hypoxia and aggregation, suggesting that the observed reduced proliferation of cells aggregated into spheroids is the result of a down-regulation of respiration. Recruitment of SVF to spheroids increased the spheroids invasive capacity but reduced respiration only in the most aggressive cells. Further, aggregation and hypoxia reduced the response to the metabolic drugs AICAR and metformin, and the chemotherapeutic agents cisplatin and paclitaxel. Our results suggest that the adaptation of cellular metabolism may contribute to enhanced survival under non-permissive conditions, and that these metabolic alterations may provide targets for future interventions that aim to enhance the survival of women with metastatic ovarian cancer.

Identification of BCL-XL as highly active survival factor and promising therapeutic target in colorectal cancer

Since metastatic colorectal cancer (CRC) is a leading cause of cancer-related death, therapeutic approaches overcoming primary and acquired therapy resistance are an urgent medical need. In this study, the efficacy and toxicity of high-affinity inhibitors targeting antiapoptotic BCL-2 proteins (BCL-2, BCL-XL, and MCL-1) were evaluated. By RNA sequencing analysis of a pan-cancer cohort comprising >1500 patients and subsequent prediction of protein activity, BCL-XL was identified as the only antiapoptotic BCL-2 protein that is overactivated in CRC. Consistently, pharmacologic and genetic inhibition of BCL-XL induced apoptosis in human CRC cell lines. In a combined treatment approach, targeting BCL-XL augmented the efficacy of chemotherapy in vitro, in a murine CRC model, and in human ex vivo derived CRC tissue cultures. Collectively, these data show that targeting of BCL-XL is efficient and safe in preclinical CRC models, observations that pave the way for clinical translation.

Bcl‑2 family: Novel insight into individualized therapy for ovarian cancer (Review)

Chemoresistance to platinum‑based chemotherapy for ovarian cancer in the advanced stage remains a formidable concern clinically. Increasing evidence has revealed that apoptosis represents the terminal events of the anti‑tumor mechanisms of a number of chemical drugs and has a close association with chemoresistance in ovarian cancer. The B‑cell lymphoma‑2 (Bcl‑2) family plays a crucial role in apoptosis and has a close association with chemoresistance in ovarian cancer. Some drugs that target Bcl‑2 family members have shown efficacy in overcoming the chemoresistance of ovarian cancer. A BH3 profiling assay was found to be able to predict how primed a cell is when treated with antitumor drugs. The present review summarizes the role of the Bcl‑2 family in mediating cell death in response to antitumor drugs and novel drugs that target Bcl‑2 family members. The application of the new functional assay, BH3 profiling, is also discussed herein. Furthermore, the present review presents the hypothesis that targeting Bcl‑2 family members may prove to be helpful for the individualized therapy of ovarian cancer in clinical practice and in laboratory research.

Organoid models in gynaecological oncology research

Cell culture and animal models represent experimental cornerstones for the investigation of tissue, organ and body physiology in the context of gynaecological research. However, their ability to accurately reflect human mechanisms in vivo is limited. The development of organoid technologies has begun to address this limitation by providing platforms ex vivo that resemble the phenotype and genotype of the multi-cellular tissue from which they were derived more accurately. In this review, we discuss advances in organoid derivation from endometrial, ovarian, fallopian tube and cervical tissue, both benign and malignant, the manipulation of organoid microenvironment to preserve stem cell populations and achieve long-term expansion and we explore the morphological and molecular kinship of organoids to parent tissue. Apart from providing new insight into mechanisms of carcinogenesis, gynaecological cancer-derived organoids can be utilised as tools for drug screening of chemotherapeutic and hormonal compounds where they exhibit interpatient variability consistent with states in vivo and xenografted tumours allowing for patient-tailored treatment strategies. Bridging organoid with bioengineering accomplishments is clearly the way forward to the generation of organoid-on-a-chip technologies enhancing the robustness of the model and its translational potential. Undeniably, organoids are expected to stand their ground in the years to come and revolutionize development and disease modelling studies.

The importance of spheroids in analyzing nanomedicine efficacy

The use of nanomedicines for cancer treatment holds a great potential due to their improved efficacy and safety. During the nanomedicine preclinical in vitro evaluation stage, these are mainly tested on cell culture monolayers. However, these 2D models are an unrealistic representation of the in vivo tumors, leading to an inaccurate screening of the candidate formulations. To address this problem, spheroids are emerging as an additional tool to validate the efficacy of new therapeutics due to the ability of these 3D in vitro cancer models to mimic the key features displayed by in vivo solid tumors. In this review, the application of spheroids for the evaluation of nanomedicines' physicochemical properties and therapeutic efficacy is discussed.

Understanding and Targeting Apoptotic Pathways in Ovarian Cancer

Ovarian cancer cells evade the immune system as well as chemotherapeutic and/or biologic treatments through inherent or acquired mechanisms of survival and drug resistance. Depending on the cell type and the stimuli, this threshold can range from external forces such as blunt trauma to programmed processes such as apoptosis, autophagy, or necroptosis. This review focuses on apoptosis, which is one form of programmed cell death. It highlights the multiple signaling pathways that promote or inhibit apoptosis and reviews current clinical therapies that target apoptotic pathways in ovarian cancer.

Strategies for Delivery of siRNAs to Ovarian Cancer Cells

The unmet need for novel therapeutic options for ovarian cancer (OC) deserves further investigation. Among the different novel drugs, small interfering RNAs (siRNAs) are particularly attractive because of their specificity of action and efficacy, as documented in many experimental setups. However, the fragility of these molecules in the biological environment necessitates the use of delivery materials able to protect them and possibly target them to the cancer cells. Among the different delivery materials, those based on polymers and lipids are considered very interesting because of their biocompatibility and ability to carry/deliver siRNAs. Despite these features, polymers and lipids need to be engineered to optimize their delivery properties for OC. In this review, we concentrated on the description of the therapeutic potential of siRNAs and polymer-/lipid-based delivery systems for OC. After a brief description of OC and siRNA features, we summarized the strategies employed to minimize siRNA delivery problems, the targeting strategies to OC, and the preclinical models available. Finally, we discussed the most interesting works published in the last three years about polymer-/lipid-based materials for siRNA delivery.

Exploiting Mitochondrial Vulnerabilities to Trigger Apoptosis Selectively in Cancer Cells

The transformation of normal cells to the cancerous stage involves multiple genetic changes or mutations leading to hyperproliferation, resistance to apoptosis, and evasion of the host immune system. However, to accomplish hyperproliferation, cancer cells undergo profound metabolic reprogramming including oxidative glycolysis and acidification of the cytoplasm, leading to hyperpolarization of the mitochondrial membrane. The majority of drug development research in the past has focused on targeting DNA replication, repair, and tubulin polymerization to induce apoptosis in cancer cells. Unfortunately, these are not cancer-selective targets. Recently, researchers have started focusing on metabolic, mitochondrial, and oxidative stress vulnerabilities of cancer cells that can be exploited as selective targets for inducing cancer cell death. Indeed, the hyperpolarization of mitochondrial membranes in cancer cells can lead to selective importing of mitocans that can induce apoptotic effects. Herein, we will discuss recent mitochondrial-selective anticancer compounds (mitocans) that have shown selective toxicity against cancer cells. Increased oxidative stress has also been shown to be very effective in selectively inducing cell death in cancer cells. This oxidative stress could lead to mitochondrial dysfunction, which in turn will produce more reactive oxygen species (ROS). This creates a vicious cycle of mitochondrial dysfunction and ROS production, irreversibly leading to cell suicide. We will also explore the possibility of combining these compounds to sensitize cancer cells to the conventional anticancer agents. Mitocans in combination with selective oxidative-stress producing agents could be very effective anticancer treatments with minimal effect on healthy cells.

CDC25A Facilitates Chemo-resistance in Ovarian Cancer Multicellular Spheroids by Promoting E-cadherin Expression and Arresting Cell Cycles

Peritoneal metastasis is the most common pathway for the spread of ovarian cancer and one of the major causes of cancer death. Ovarian cancer cells in ascites prefer to aggregate into the multicellular spheroids (MCS) with an inadequate response to chemotherapy. In this study, gene expression analysis implicated that ovarian cancer MCS had its unique expression pattern and the cell cycle-related pathways were prominently altered in MCS cells compared to the monolayer adherent cells. Flow cytometry and western blots confirmed the cell cycle stagnancy in MCS. Among the cell cycle-related proteins, we found that expression of CDC25A was upregulated in MCS and displayed a time-dependent decrease during the transition from MCS to monolayer adherent cells. Loss-of-function studies showed that CDC25A promoted cisplatin-resistance and paclitaxel-resistance and inhibited the drug-induced apoptosis in ovarian cancer MCS. Mechanically, CDC25A impeded cell cycle progression in MCS cells, enhanced their structure integrity, and maintained upregulation of E-cadherin in MCS cells. Accordingly, addition of NSC95397, a small molecular inhibitor of CDC25A, sensitized the ovarian cancer MCS to chemotherapeutic agents. This provides us a novel strategy for the treatment of ovarian cancer peritoneal metastasis and may help improve the overall survival of ovarian cancer patients.