Divergent Metabolic Effects of Metformin Merge to Enhance Eicosapentaenoic Acid Metabolism and Inhibit Ovarian Cancer In Vivo

NMR Metabolomics of Primary Ovarian Cancer Cells in Comparison to Established Cisplatin-Resistant and -Sensitive Cell Lines

Cancer cell lines are frequently used in metabolomics, such as in vitro tumor models. In particular, A2780 cells are commonly used as a model for ovarian cancer to evaluate the effects of drug treatment. Here, we compare the NMR metabolomics profiles of A2780 and cisplatin-resistant A2780 cells with those of cells derived from 10 patients with high-grade serous ovarian carcinoma (collected during primary cytoreduction before any chemotherapeutic treatment). Our analysis reveals a substantial similarity among all primary cells but significant differences between them and both A2780 and cisplatin-resistant A2780 cells. Notably, the patient-derived cells are closer to the resistant A2780 cells when considering the exo-metabolome, whereas they are essentially equidistant from A2780 and A2780-resistant cells in terms of the endo-metabolome. This behavior results from dissimilarities in the levels of several metabolites attributable to the differential modulation of underlying biochemical pathways. The patient-derived cells are those with the most pronounced glycolytic phenotype, whereas A2780-resistant cells mainly diverge from the others due to alterations in a few specific metabolites already known as markers of resistance.

Intermittent fasting induced ketogenesis inhibits mouse epithelial ovarian cancer by promoting antitumor T cell response

In various cancer models, dietary interventions have been shown to inhibit tumor growth, improve anticancer drug efficacy, and enhance immunity, but no such evidence exists for epithelial ovarian cancer (EOC), the most lethal gynecologic cancer. The anticancer immune responses induced by 16-h intermittent fasting (IF) were studied in mice with EOC. IF consistently reduced metabolic growth factors and cytokines that stimulate tumor growth, creating a tumor-hostile environment. Immune profiling showed that IF dramatically alters anti-cancer immunity by increasing CD4+ and CD8+ cells, Th1 and cytotoxic responses, and metabolic fitness. β-hydroxy butyrate (BHB), a bioactive metabolite produced by IF, partially imitates its anticancer effects by inducing CD8+ effector function. In a direct comparison, IF outperformed exogenous BHB treatment in survival and anti-tumor immune response, probably due to increased ketogenesis. Thus, IF and one of its metabolic mediators BHB suppress EOC growth and sustain a potent anti-tumor T cell response.

Molecular targets of metformin against ovarian cancer based on network pharmacology

The objective of this study was to analyze potential targets of metformin against ovarian cancer (OC) through network pharmacology. Pharmacodynamic targets of metformin were predicted using the Bioinformatics Analysis Tool for the molecular mechanism of traditional Chinese medicine (BATMAN), Drugbank, PharmMapper, SwissTargetPrediction, and TargetNet databases. R was utilized to analyze the gene expression of OC tissues, normal/adjacent noncancerous tissues, and screen differentially expressed genes (DEGs) in the Gene Expression Omnibus (GEO) and the Cancer Genome Atlas (TCGA) + Genotype-Tissue Expression (GTEx) datasets. STRING 11.0 was utilized to explore the protein-protein interaction (PPI) of metformin target genes differentially expressed in OC. Cytoscape 3.8.0 was used to construct the network and screen the core targets. Additionally, gene ontology (GO) annotation and enrichment and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed for the common targets of metformin and OC through the DAVID 6.8 database. A total of 95 potential common targets of metformin and OC were identified from the intersection of 255 potential pharmacodynamic targets of metformin and 10,463 genes associated with OC. Furthermore, 10 core targets were screened from the PPI network [e.g., interleukin (IL) 1B, KCNC1, ESR1, HTR2C, MAOB, GRIN2A, F2, GRIA2, APOE, PTPRC]. In addition, it was shown in GO enrichment analysis that the common targets were mainly associated with biological processes (i.e., response to stimuli or chemical, cellular processes, and transmembrane transport), cellular components (i.e., plasma membrane, cell junction, and cell projection), and molecular functions (i.e., binding, channel activities, transmembrane transporter activity, and signaling receptor activities). Furthermore, it was indicated by KEGG pathway analysis that the common targets were enriched in metabolic pathways. The critical molecular targets and molecular pathways of metformin against OC were preliminarily determined by bioinformatics-based network pharmacology analysis, providing a basis, and reference for further experimental studies.

Intermittent Fasting induced ketogenesis inhibits mouse epithelial ovarian tumors by promoting anti-tumor T cell response

Epithelial Ovarian Cancer (EOC) is the most lethal gynecologic cancer with limited genetic alterations identified that can be therapeutically targeted. In tumor bearing mice, short-term fasting, fasting mimicking diet and calorie restriction enhance the activity of antineoplastic treatment by modulating systemic metabolism and boosting anti-tumor immunity. We tested the outcome of sixteen-hour intermittent fasting (IF) on mouse EOC progression with focus on fasting driven antitumor immune responses. IF resulted in consistent decrease of tumor promoting metabolic growth factors and cytokines, recapitulating changes that creates a tumor antagonizing environment. Immune profiling revealed that IF profoundly reshapes anti-cancer immunity by inducing increase in CD4+ and CD8+ cells, paralleled by enhanced antitumor Th1 and cytotoxic responses, by enhancing their metabolic fitness. Metabolic studies revealed that IF generated bioactive metabolite BHB which can be a potential substitute for simulating the antitumor benefits of IF. However, in a direct comparison, IF surpassed exogenous BHB therapy in improving survival and activating anti-tumor immune response. Thus, our data provides strong evidence for IF and its metabolic mediator BHB for ameliorating EOC progression and as a viable approach in maintaining and sustaining an effective anti-tumor T cell response.

Nutraceutical-Based Nanoformulations for Breast and Ovarian Cancer Treatment

Different strategies have been investigated for a more satisfactory treatment of advanced breast cancer, including the adjuvant use of omega-3 polyunsaturated fatty acids (PUFAs). These nutritional compounds have been shown to possess potent anti-inflammatory and antiangiogenic activities, the capacity to affect transduction pathways/receptors involved in cell growth and to reprogram tumor microenvironment. Omega-3 PUFA-containing nanoformulations designed for drug delivery in breast cancer were shown to potentiate the effects of enclosed drugs, enhance drug delivery to target sites, and minimize drug-induced side effects. We have critically analyzed here the results of the most recent studies investigating the effects of omega-3 PUFA-containing nanoformulations in breast cancer. The anti-neoplastic efficacy of omega-3 PUFAs has also been convincingly demonstrated by using preclinical in vivo models of ovarian cancer. The results obtained are critically analyzed here and seem to provide a sufficient rationale to move to still lacking interventional clinical trials, as well as to evaluate possible advantages of enclosing omega-3 PUFAs to drug-delivery nanosystems for ovarian cancer. Future perspectives in this area are also provided.

Divergent Metabolic Effects of Metformin Merge to Enhance Eicosapentaenoic Acid Metabolism and Inhibit Ovarian Cancer In Vivo

Metformin is being actively repurposed for the treatment of gynecologic malignancies including ovarian cancer. We investigated if metformin induces analogous metabolic changes across ovarian cancer cells. Functional metabolic analysis showed metformin caused an immediate and sustained decrease in oxygen consumption while increasing glycolysis across A2780, C200, and SKOV3ip cell lines. Untargeted metabolomics showed metformin to have differential effects on glycolysis and TCA cycle metabolites, while consistent increased fatty acid oxidation intermediates were observed across the three cell lines. Metabolite set enrichment analysis showed alpha-linolenic/linoleic acid metabolism as being most upregulated. Downstream mediators of the alpha-linolenic/linoleic acid metabolism, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were abundant in all three cell lines. EPA was more effective in inhibiting SKOV3 and CaOV3 xenografts, which correlated with inhibition of inflammatory markers and indicated a role for EPA-derived specialized pro-resolving mediators such as Resolvin E1. Thus, modulation of the metabolism of omega-3 fatty acids and their anti-inflammatory signaling molecules appears to be one of the common mechanisms of metformin's antitumor activity. The distinct metabolic signature of the tumors may indicate metformin response and aid the preclinical and clinical interpretation of metformin therapy in ovarian and other cancers.