Growth Of Epithelial Ovarian Cancer Research Articles

Germ cell-specific gene 2 accelerates cell cycle in epithelial ovarian cancer by inhibiting GSK3α-p27 cascade

Epithelial ovarian cancer (EOC) is one of the most common malignant gynecological tumors with rapid growth potential and poor prognosis, however, the molecular mechanism underlying its outgrowth remained elusive. Germ cell-specific gene 2 (GSG2) was previously reported to be highly expressed in ovarian cancer and was essential for the growth of EOC. In this study, GSG2-knockdown cells and GSG2-overexpress cells were established through lentivirus-mediated transfection with Human ovarian cancer cells HO8910 and SKOV3. Knockdown of GSG2 inhibited cell proliferation and induced G2/M phase arrest in EOC. Interestingly, the expression of p27, a well-known regulator of the cell cycle showed a most significant increase after GSG2 knockdown. Further phosphorylation-protein array demonstrated the phosphorylation of GSK3αSer21 decreased in GSG2-knockdown cells to the most extent. Notably, inhibiting GSK3α activity effectively rescued GSG2 knockdown’s suppression on cell cycle as well as p27 expression in EOC. Our study substantiates that GSG2 is able to phosphorylate GSK3α at Ser21 and then leads to the reduction of p27 expression, resulting in cell cycle acceleration and cell proliferation promotion. Thus, GSG2 may have the potential to become a promising target in EOC.

Abstract 4423: Cholesterol and arachidonic acid promote the tumor growth of epithelial ovarian cancer via MAPK signaling pathway

Abstract Introduction: Previously, we reported that VLDL promoted cell proliferation of epithelial ovarian cancer (EOC) cells in vitro. In vivo, we also confirmed that High-Fat Diet (HFD) strongly promoted the tumor growth of EOC. These results suggest that lipid molecules in HFD might contribute to cell proliferation of EOC cell. In this study, we performed metabolome analysis and analyzed the metabolomic profile of lipid molecules of HFD fed mouse serum. Finally, we demonstrated that some lipid molecules promoted the cell proliferation of EOC cells in vitro and vivo. Methods: We obtained the serum of HFD and normal diet (ND) fed mouse (non-tumor bearing) and performed metabolome analysis to identify the lipid molecules which associate with cell proliferation. In addition, we demonstrated that the lipid molecules promoted cell proliferation and activated signaling pathway of EOC cells in vitro. Moreover, we evaluated that the lipid molecules-rich diet promoted the tumor growth of EOC in vivo. Results: The tumor growth of EOC (EOC cell line; KURAMOCHI and RMG-I) was significantly promoted by HFD compared to ND in vivo (p < 0.05, respectively). Metabolome analysis using the serum of HFD and ND fed mouse (non-tumor bearing) detected 210 metabolites, and principal component analysis showed obvious different metabolic profiles of HFD fed mouse serum compared to ND. Partial least squares-discriminant analysis revealed cholesterol and arachidonic acid (AA) as the lipid molecules with high VIP score in the serum of HFD fed mouse. In vitro, cholesterol and AA significantly promoted cell proliferation, respectively (p < 0.05) through the activation of MAPK signaling pathway. In vivo, we also confirmed that cholesterol and AA-rich feed promoted the tumor growth of EOC, respectively (p < 0.05). Conclusions: Cholesterol and AA significantly promoted the tumor growth of epithelial ovarian cancer through the activation of MAPK signaling pathway. Citation Format: Hitomi Sakaguchi-Mukaida, Kosuke Hiramatsu, Mamoru Kakuda, Satoshi Nakagawa, Toshihiro Kimura, Yutaka Ueda, Tadashi Kimura. Cholesterol and arachidonic acid promote the tumor growth of epithelial ovarian cancer via MAPK signaling pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4423.

Abstract B090: Gut microbial suppression of epithelial ovarian cancer and attenuation of chemoresistance: opportunity for probiotics in patient care to improve survival

Abstract Up to 80% of ovarian cancer patient tumors will recur, become platinum resistant, and require additional treatment. Platinum resistance is correlated with poor overall survival and reduced therapeutic options for epithelial ovarian cancer (EOC) patients, a leading cause of gynecologic cancer death. Our findings identify a microbial tumor suppressive activity that is disrupted by antibiotics including vancomycin, metronidazole, neomycin, and ampicillin. Starting with a retrospective clinical analysis of OC patients, we found antibiotic use during chemotherapy treatment is associated with poor overall survival. In pre-clinical studies, we found that broad spectrum antibiotics (ABX) therapy, including metronidazole, ampicillin, vancomycin, and neomycin, augments tumor growth of EOC and leads to resistance to cisplatin. In follow up studies we determined vancomycin and metronidazole are sufficient to accelerate ovarian cancer growth and response to cisplatin therapy. Mechanistically, we determined that tumors from ABX treated mice exhibited increased proliferation, reduced apoptosis, decreased DNA damage in cisplatin treated specimens, and increased angiogenesis compared to control treated mice. As these are functional indicators of increased cancer stem cells (CSCs), we analyzed the tumors by RNAseq and single cell spheroid analysis for stem cell frequency. Tumors from ABX treated immune competent mice contained a higher frequency of cisplatin-induced CSCs than tumors from control treated mice. Tumors from untreated mice did not show increased CSCs. We determined that ABX treatment unmasked a microbiome dependent immune suppressor of cancer stem cells as tumors from immune deficient mice exhibited cisplatin induced CSCs in presence or absence of ABX. Finally, we determined that repletion of the microbiome via cecal transplants derived from ABX or control treated mice to recolonize the microbiome of ABX treated mice is sufficient to ameliorate the chemoresistance and survival of ABX treated mice indicative of a gut-derived tumor suppressor. We identified microbial metabolites suppressed in ovarian cancer patients and reduced by ABX in mice as candidate compounds that underlie the tumor suppressive activity. Collectively, the findings indicate the gut microbiome delivers a tumor suppressive signal that is unmasked by ABX treatment. We propose a probiotic strategy as a complement to standard of care may yield improved outcomes in ovarian cancer treatment. Citation Format: Ofer Reizes, Laura Chambers, Chad M. Michener, Mark Brown, Justin D. Lathia, Mohammed Dwidar, Naseer Sangwan, Roberto Vargas, Zeneng Wang, Adeline Hajjar. Gut microbial suppression of epithelial ovarian cancer and attenuation of chemoresistance: opportunity for probiotics in patient care to improve survival [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr B090.

Triptolide inhibits epithelial ovarian tumor growth by blocking the hedgehog/Gli pathway.

Epithelial ovarian cancer (EOC), the most predominant subtype of ovarian cancer (OC), involves poor prognosis and exhibits high aggression. Triptolide (TPL), like other Chinese herbs, has historically played a significant role in modern medicine. The screening system based on Gli-dependent luciferase reporter activity assessed the effects of over 800 natural medicinal materials on hedgehog (Hh) signaling pathway activity and discovered that TPL had an excellent inhibitory effect on Hh signaling pathway activity. However, the significance and mechanism of TPL involvement in regulating the Hh pathway have not been well explored. Thus, this work aimed to understand better how TPL affects the Hh pathway activity, which, in turn, influences the biological behavior of EOC. Our findings observed that Smo agonist SAG-induced EOC cell proliferation, migration, and invasion were drastically reversed by TPL in a concentration-dependent pattern. Further evidence suggested that TPL promotes the degradation of Gli1 and Gli2 to inhibit the activity of the Hh signaling pathway by relying on Gli1 and Gli2 ubiquitination. Our in vivo studies also confirmed that TPL could significantly inhibit the tumor growth of EOC. Taken together, our results revealed that one of the antitumor mechanisms of TPL was the targeted inhibition of the Hh/Gli pathway.

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 Tcell response.

CHAF1A promotes the proliferation and growth of epithelial ovarian cancer cells by affecting the phosphorylation of JAK2/STAT3 signaling pathway

The molecular mechanism of chromatin assembly factor 1 unit A (CHAF1A) promoting the proliferation and growth of epithelial ovarian cancer (EOC) cells hasn’t been reported at present. In this study, recombinant CHAF1A siRNA/overexpression plasmid (si-RNA1/pcDNA3.1-CHAF1A) was designed and constructed, and stable cell lines with knockdown or overexpression of CHAF1A were constructed. The changes of JAK2/STAT3 pathway were detected by Western blot. JAK2/STAT3 pathway was inhibited by Peficitinib, and then cell proliferation and growth ability were detected. Bioinformatics analysis suggested that CHAF1A was up-regulated in epithelial ovarian cancer. JAK2/STAT3 pathway phosphorylation was inhibited in si-RNA1 group, while it was increased in pcDNA3.1-CHAF1A group. After inhibiting JAK2/STAT3 pathway, the promoting effect of CHAF1A on epithelial ovarian cancer cell proliferation disappeared, meanwhile the inhibitory effect of CHAF1A on apoptosis enhanced. In conclusion, CHAF1A promotes the proliferation and growth of epithelial ovarian cancer cells by affecting the phosphorylation of JAK2/STAT3 signaling pathway.

Caloric restriction induces macrophage reprogramming and improved epithelial ovarian cancer survival

Abstract Calorie restriction (CR) without malnutrition is a dietary intervention where energy intake is reduced by 15 – 40%. The benefits of CR in improving various diseases and extending lifespan has led its investigation in cancer. We have reported 30% CR to limit epithelial ovarian cancer (EOC) progression. Here, we highlight the ability of CR to induce immuno-metabolic reprogramming of tumor associated macrophages and improve EOC survival. Female C57/B6 mice were injected intraperitoneally with 8 × 10 6mouse EOC ID8 (p53 +/+, p53 −/−, or ID8 p53 −/−,BRCA1−/−) cells and fed ad libitum (RD) or subjected to 30% CR. Immune profiling was done by flow cytometry. Metabolic phenotype was determined by XF seahorse analyzer. Macrophage marker were measured by qPCR and western blot. Mice on 30% CR exhibited reduced tumor progression and increased overall survival compared to RD mice in all ID8 models as indicated by median survival; ID8 p53+/+(65 vs 95 days), ID8 p53−/−(50.5 vs 76.5 days), and ID8 p53−/−,BRCA1−/−(44 vs 53 days). Immune profiling showed increase in antitumor associated pro-inflammatory macrophages (F4/80+CD38+) and decrease in protumor anti-inflammatory (F4/80+CD206+) macrophages, increasing the pro / anti-inflammatory ratio. Pro-inflammatory macrophages showed increased intracellular iNOS. The phenotype change in CR mice was accompanied with reprogrammed energy metabolism indicated by increased glycolysis, reflective of pro-inflammatory macrophages. Decrease in anti-inflammatory macrophages resulted in robust anti-tumor T cell response. A 30% CR reprograms macrophage metabolism and promotes their pro-inflammatory anti-tumor phenotype, restores antitumor immunity resulting in reduced EOC growth and improved survival R01 B11209 to RR Henry Ford Cancer institute Post Doctorate Fellowship to HS

Exosomes from Human Omental Adipose-Derived Mesenchymal Stem Cells Secreted into Ascites Promote Peritoneal Metastasis of Epithelial Ovarian Cancer.

Epithelial ovarian cancer (EOC) patients frequently develop peritoneal metastasis, especially in the human omentum. However, the mechanism underlying this propensity remains unknown. A previous study found that human omental adipose-derived mesenchymal stem cells are potentially involved in ovarian cancer growth and metastasis, but the results were inconsistent and even contradictory. In addition, the underlying mechanisms of visceral adipose metastasis remain poorly understood. Here, our goal is to clarify the role and mechanism of human omental adipose-derived mesenchymal stem cells (HO-ADSCs) in EOC cancer growth and metastasis. We first found that human omental tissue conditioned medium (HO-CM) enhances EOC cell function. Subsequent coculture studies indicated that HO-ADSCs increase the growth, migratory and invasive capabilities of ovarian cancer cells. Then, we demonstrated that exosomes secreted by HO-ADSCs (HO-ADSC exosomes) enhanced ovarian cancer cell function, and further mechanistic studies showed that the FOXM1, Cyclin F, KIF20A, and MAPK signaling pathways were involved in this process. In addition, subcutaneous tumorigenesis and peritoneal metastatic xenograft experiments provided evidence that HO-ADSC exosomes promote ovarian cancer growth and metastasis in vivo. Finally, our clinical studies provided evidence that ascites from ovarian cancer patients enhance EOC cell line proliferation, migration, and invasion in vitro. The present study indicated that HO-ADSC exosomes are secreted into ascites and exert a tumor-promoting effect on EOC growth and metastasis, providing a new perspective and method to develop future novel therapeutic strategies for the treatment of ovarian cancer.

Extracellular vesicle-packaged miR-181c-5p from epithelial ovarian cancer cells promotes M2 polarization of tumor-associated macrophages via the KAT2B/HOXA10 axis.

The molecular mechanistic actions of tumor-derived extracellular vesicles (EVs) in modulating macrophage polarization in the tumor microenvironment of epithelial ovarian cancer (EOC) is largely unknown. The study was performed to clarify the effect and downstream mechanism of microRNA-181c-5p (miR-181c-5p)-containing EVs from EOC cells in the M2 polarization of tumor-associated macrophages (TAMs). EVs were isolated from normoxic and hypoxic human EOC cells SKOV3. Human mononuclear cell THP-1 was induced by phorbol-12-myristate-13-acetate to differentiate into TAMs. The targeting relationship between miR-181c-5p and KAT2B was verified by dual luciferase reporter gene assay. The interaction between KAT2B and HOXA10 was detected by immunofluorescence, Co-IP and ChIP assays. EdU staining, the scratch test and Transwell assay were used to assess the resultant cell proliferation, migration and invasion. The mouse xenograft model and the pulmonary metastasis model were developed through intraperitoneal injection of SKOV3 cells and tail vein injection of THP-1 cells, respectively. Hypoxic SKOV3 cell-derived EVs could be internalized by TAMs. SKOV3 cell-derived EVs induced by hypoxia (H-EVs) promoted M2 polarization of TAMs and facilitated the proliferation, migration and invasion of SKOV3 cells. miR-181c-5p was highly expressed in H-EVs and promoted the M2 polarization of TAMs. Further, miR-181c-5p targeted KAT2B, upregulated HOXA10 and activated the JAK1/STAT3 pathway, thereby promoting the M2 polarization of TAMs. In both mouse models, H-EV-derived miR-181c-5p promoted growth and metastasis of EOC cells. The miR-181c-5p-containing EVs from hypoxic EOC cells may upregulate HOXA10 by targeting KAT2B and activate the JAK1/STAT3 pathway to promote the M2 polarization of TAMs, ultimately promoting growth and metastasis of EOC cells in vitro and in vivo.

The impact of ketogenic diet on the gut microbiome and tumor growth in an in vivo epithelial ovarian cancer model (105)

<b>Objectives:</b> The ketogenic diet (KD) is hypothesized to protect against cancer progression due to metabolic reprogramming. Sustained dietary modifications alter the composition of the gut microbiome, which may influence tumor growth. Here, we present the impact of KD on the gut microbiome in relation to epithelial ovarian cancer (EOC) progression. <b>Methods:</b> C57Bl/6J ID8 (luciferase-tagged) tumor-bearing mice were fed a KD (10% protein, 0% carbohydrates, 90% fat), high fat diet (HFD) (10% protein, 15% carbohydrates, 75% fat), and control diet (CD) (10% protein, 77% carbohydrates, and 13% fat) (<i>n</i>=10 mice per group). Blood ketone and glucose levels were serially measured. EOC tumor growth was monitored with <i>in Vivo</i> Imaging System (IVIS) via intraperitoneal D-luciferin. Total tumor burden was measured in total flux (photons/second). Stool was collected at baseline, midpoint (four weeks after tumor cell injection), and endpoint (tumor mass of >150 mm³, ascites development, or weight loss >20%); 16S rDNA was isolated, and sequence reads were assigned to genus-level amplicon sequence variants (ASV) in DADA2 as well as analyzed for alpha and beta microbial diversity using Phyloseq. Statistical tests included analysis of variance (ANOVA), permutational multivariate analysis (PERMANOVA), linear regression, and Wilcoxon test. A p-value of <0.05 was considered statistically significant. <b>Results:</b> KD-fed mice exhibited an increase in ketone blood levels (2.22 mmol/L) compared to both HFD- (0.7 mmol/L, p<0.0001) and CD-fed mice (0.61 mmol/L, p<0.0001) at the endpoint. There was no significant difference in overall glucose levels or body mass composition between the groups. By day 42, there was a 9.1-fold increase in tumor growth from baseline in the KD-fed group compared to HFD-and CD-fed groups (9.1 vs 2.0 vs 3.1-fold, respectively, p<0.001 and p<0.001). By study endpoint, KD-fed mice exhibited a statistically significant increase in gut microbial alpha diversity in comparison to HFD and CD (p<0.01 at the midpoint and p<0.05 at the endpoint). Brays-Curtis dissimilarity based on microbial beta diversity demonstrated that the relative abundance of gut microbial species between the three groups was similar at baseline. However, KD-fed mice had significantly altered gut microbial composition than HFD-and CD-fed mice at both midpoint and endpoint (p = 0.001); 16S data analysis demonstrated a relative decrease in <i>Lactobacillus</i> and <i>Coriobacteriaceae</i> species and a relative increase in <i>Romboutsia</i> and <i>Akkermansia</i> species in the KD-fed mice. <b>Conclusions:</b> In our EOC murine model, KD was associated with increased EOC growth and distinct gut microbial alterations in comparison to HFD and CD. KD-fed mice exhibited increased gut microbial diversity over time, a relative depletion of bacterial species <i>Lactobacillus</i> and <i>Coriobacteriaceae</i>, and a relative enrichment of bacterial species <i>Romboutsia</i> and <i>Akkermansia</i>. Further studies are needed to understand the mechanisms underlying the relationship between KD, the gut microbiome, and EOC progression.Fig. 1

Combined inhibition of BADSer99 phosphorylation and PARP ablates models of recurrent ovarian carcinoma

BackgroundPoly (ADP-ribose) polymerase inhibitors (PARPis) have been approved for the treatment of recurrent epithelial ovarian cancer (EOC), regardless of BRCA status or homologous recombination repair deficiency. However, the low response of platinum-resistant EOC, the emergence of resistance in BRCA-deficient cancer, and therapy-associated toxicities in patients limit the clinical utility of PARPis in recurrent EOC.MethodsThe association of phosphorylated (p) BADS99 with clinicopathological parameters and survival outcomes in an EOC cohort was assessed by immunohistochemistry. The therapeutic synergy, and mechanisms thereof, between a pBADS99 inhibitor and PARPis in EOC was determined in vitro and in vivo using cell line and patient-derived models.ResultsA positive correlation between pBADS99 in EOC with higher disease stage and poorer survival is observed. Increased pBADS99 in EOC cells is significantly associated with BRCA-deficiency and decreased Cisplatin or Olaparib sensitivity. Pharmacological inhibition of pBADS99 synergizes with PARPis to enhance PARPi IC50 and decreases survival, foci formation, and growth in ex vivo culture of EOC cells and patient-derived organoids (PDOs). Combined inhibition of pBADS99 and PARP in EOC cells or PDOs enhances DNA damage but impairs PARPi stimulated DNA repair with a consequent increase in apoptosis. Inhibition of BADS99 phosphorylation synergizes with Olaparib to suppress the xenograft growth of platinum-sensitive and resistant EOC. Combined pBADS99-PARP inhibition produces a complete response in a PDX derived from a patient with metastatic and chemoresistant EOC.ConclusionsA rational and efficacious combination strategy involving combined inhibition of pBADS99 and PARP for the treatment of recurrent EOC is presented.

Suppression of the ABCA1 Cholesterol Transporter Impairs the Growth and Migration of Epithelial Ovarian Cancer.

Simple SummaryEpithelial ovarian cancer (EOC) is the most lethal gynaecological cancer. Over 80% of cases have already spread at diagnosis, and these patients face a five-year survival rate of 35%. EOC cells often spread to the greater omentum, an abdominal fat pad. Here, EOC cells take-up cholesterols. Excessive amounts of cholesterol are lethal; thus, we proposed that the ABCA1 cholesterol transporter exports cholesterol from serous EOC cells to maintain cholesterol balance. Indeed, we found that reducing the level of ABCA1 could suppress serous EOC growth in two-dimensional as well as three-dimensional cell culture and also hindered their migration, a key process required for cancer spread. We also identified drugs that impair EOC cell growth by inhibiting cholesterol export. Our data demonstrate that disrupting the cholesterol balance by targeting ABCA1 may be an effective treatment strategy for EOC patients.Background: Epithelial ovarian cancer (EOC) is the most lethal gynaecological malignancy with over 80% of cases already disseminated at diagnosis and facing a dismal five-year survival rate of 35%. EOC cells often spread to the greater omentum where they take-up cholesterol. Excessive amounts of cholesterol can be cytocidal, suggesting that cholesterol efflux through transporters may be important to maintain homeostasis, and this may explain the observation that high expression of the ATP-binding cassette A1 (ABCA1) cholesterol transporter has been associated with poor outcome in EOC patients. Methods: ABCA1 expression was silenced in EOC cells to investigate the effect of inhibiting cholesterol efflux on EOC biology through growth and migration assays, three-dimensional spheroid culture and cholesterol quantification. Results: ABCA1 suppression significantly reduced the growth, motility and colony formation of EOC cell lines as well as the size of EOC spheroids, whilst stimulating expression of ABCA1 reversed these effects. In serous EOC cells, ABCA1 suppression induced accumulation of cholesterol. Lowering cholesterol levels using methyl-B-cyclodextrin rescued the effect of ABCA1 suppression, restoring EOC growth. Furthermore, we identified FDA-approved agents that induced cholesterol accumulation and elicited cytocidal effects in EOC cells. Conclusions: Our data demonstrate the importance of ABCA1 in maintaining cholesterol balance and malignant properties in EOC cells, highlighting its potential as a therapeutic target for this disease.

Disabling partners in crime: Gold nanoparticles disrupt multicellular communications within the tumor microenvironment to inhibit ovarian tumor aggressiveness

The tumor microenvironment (TME) plays a key role in the poor prognosis of many cancers. However, there is a knowledge gap concerning how multicellular communication among the critical players within the TME contributes to such poor outcomes. Using epithelial ovarian cancer (EOC) as a model, we show how crosstalk among cancer cells (CC), cancer associated fibroblasts (CAF), and endothelial cells (EC) promotes EOC growth. We demonstrate here that co-culturing CC with CAF and EC promotes CC proliferation, migration, and invasion in vitro and that co-implantation of the three cell types facilitates tumor growthin vivo. We further demonstrate that disruption of this multicellular crosstalk using gold nanoparticles (GNP) inhibits these pro-tumorigenic phenotypesin vitroas well as tumor growthin vivo. Mechanistically, GNP treatment reduces expression of several tumor-promoting cytokines and growth factors, resulting in inhibition of MAPK and PI3K-AKT activation and epithelial-mesenchymal transition - three key oncogenic signaling pathways responsible for the aggressiveness of EOC.The current work highlights the importance of multicellular crosstalk within the TME and its role for the aggressive nature of EOC, and demonstrates the disruption of these multicellular communications by self-therapeutic GNP, thus providing new avenues to interrogate the crosstalk and identify key perpetrators responsible for poor prognosis of this intractable malignancy.

Development of a Novel 3D Model to Investigate the Role of Heterogeneity in Ovarian Cancer Chemoresistance

More than 70% of all patients diagnosed with epithelial ovarian cancer (EOC) succumb to their disease making EOC the most lethal gynecological cancer. The astonishingly high mortality rate of EOC can be explained largely by the fact that 75% of all cases are diagnosed at advanced or metastatic stages thus highlighting the urgency to better understand what cues in the primary tumor microenvironment (TME) promote metastasis. Up to 80% of these patients experience disease reoccurrence demonstrating that in addition to early events in EOC progression, how EOC populations acquire resistance to our current gold standard of treatment is poorly understood. While two-dimensional (2D) in vitro studies of ovarian cancer have provided fundamental insight, three-dimensional (3D) culture systems that more accurately mimic the in vivoTME in terms of biomechanical and biochemical stimuli, are critical research tools in studying ovarian cancer progression. To address this problem, we have developed a 3D culture model that allows for spatial and temporal control of cancer cell interactions with their TME. Our model has the capability to support 3D EOC growth in a mechanically relevant environment over at least a 4-week period while a physically separated fibroblast-rich matrix evolves under the influence of EOC secreted factors. This model maintains the spatial heterogeneity present in both the EOC growth, as well as the developing microenvironment. Using this model, we chose to address two critical gaps in knowledge in the progression of EOC, namely how heterogenous EOC populations acquire resistance and how EOC progression alters surrounding stromal cell populations to promote invasion and metastasis. Our work reveals that altering the dose and administration schedule of paclitaxel can produce heterogenous EOC populations that differ in the acquisition of single or multidrug resistance. By comparing these populations, we found that paclitaxel treatment induced nonuniform metabolic reprogramming across EOC populations which was crucial for the establishment of single and multidrug resistance. Our results provide insight into how current gold standard chemotherapies contribute to the development of chemoresistant EOC subpopulations and describe potential vulnerabilities in these cells that can be exploited for more effective treatment.

Epithelial Ovarian Cancer microenvironment regulates Myeloid cell metabolism to confer immunosuppression via glutamine metabolism.

Abstract Myeloid Cells are a major constituent of epithelial ovarian cancer (EOC) microenvironment that confer immunosuppression and promote tumor growth. Using the syngeneic ID8 EOC model we show that its microenvironment is enriched in myeloid cell recruiting factors like GM-CSF, G-CSF, VEGF, TNF-a, IL-1b and IL-6. Tumor microenvironment (TME) exposed myeloid cells are highly immunosuppressive as seen by increased expression of CSF-R, S100a9, STAT-3, VEGF, TNF-a, iNOS, STAT-3 and T-cell suppression activity. TME exposed myeloid cells exhibited an activated metabolic phenotype that was fueled by glutamine dependent oxidative phosphorylation as assessed by XFe seahorse analyzer and targeted metabolomics. Deprivation of glutamine or use of a glutaminase inhibitor, BPTES reduced oxidative phosphorylation, decreased immunosuppressive markers and protected from T-cell suppression. Targeted energy metabolism gene expression arrays revealed that the mitochondrial enzyme, dihydrolipoamide succinyl transferase (DLST), a component of alpha-ketoglutarate dehydrogenase (a-KG) complex in TCA cycle, was elevated in TME exposed myeloid cells. Glutamine deprivation reduced DLST expression, suggesting that DLST expression is dependent on availability of glutamine. A novel small molecule inhibitor of a-KG complex, 3-methyl 2-oxalo valeric acid, regressed EOC growth, reversed myeloid cell energy phenotype and alleviated T-cell suppression. We propose that EOC induced expression of DLST metabolically regulates the immunosuppressive function of myeloid cells and targeting DLST may represent a new strategy to reduce immunosuppressive environment plaguing ovarian cancer.

The gut microbiome attenuates epithelial ovarian cancer growth and platinum sensitivity: Novel opportunities for ovarian cancer treatment

The gut microbiome attenuates epithelial ovarian cancer growth and platinum sensitivity: Novel opportunities for ovarian cancer treatment

Follicle-stimulating hormone\xa0promotes the proliferation of\xa0epithelial ovarian cancer\xa0cells by activating sphingosine kinase

Follicle-stimulating hormone (FSH) is closely related to the pathogenesis and progression of epithelial ovarian cancer (EOC). However, until now, knowledge relating to FSH-driven signalling pathways that lead to the growth of EOC remained incomplete. We sought to explore whether sphingosine kinase (SphK) could mediate FSH-induced ovarian cancer cell proliferation and which pathway might be involved in this process. The expression of phospho-SphK1 and phospho-SphK2 was detected in sections of EOC tissues by Immunohistochemical staining, and clinical significances were analyzed by statistical analysis. EOC cells were treated with FSH or/and SKI-II. CCK8 assays and colony formation assays were used to investigate cell proliferation. Western blot was carried out to detect protein expression in EOC cell line after treated with FSH. Here, for the first time, we provide evidence that high expression levels of phospho-SphK1 and phospho-SphK2 were both prognostic indicators of overall survival (OS) in EOC. Additionally, the expression levels of both phospho-SphK1 and phospho-SphK2 were closely correlated with the expression level of follicle-stimulating hormone receptor (FSHR) in ovarian cancer tissues. FSH stimulated the phosphorylation of both SphK1 and SphK2 and was able to regulate the survival and growth of ovarian cancer cells by activating SphK1 and SphK2 through ERK1/2. Both isoenzymes of SphK were equally responsible for FSH-induced cell proliferation of EOC. Both Erk1/2 and Akt activation play important roles in mediating FSH-induced cell proliferation after phosphorylation of SphK. Moreover, our data demonstrated that S1P receptor 1 (S1PR1) and S1PR3, key components of the SphK signalling system, were involved in FSH-mediated proliferation of EOC. Taken together, the results of the current study revealed that SphK is an essential mediator in FSH-induced proliferation of ovarian cancer cells in EOC, which indicates a new signalling pathway that controls FSH-mediated growth in EOC and suggests a new strategy that pharmaceutically targets both isoenzymes of SphK for the management of ovarian cancer.

High neuropilin and tolloid-like 1 expression associated with metastasis and poor survival in epithelial ovarian cancer via regulation of actin cytoskeleton.

Abnormal expression of neuropilin and tolloid‐like 1 (NETO1) has been detected in some human carcinomas. However, the expression of NETO1 and the underlying mechanism in epithelial ovarian cancer (EOC) remain unknown. In this study, we found that a higher NETO1 expression in EOC tissue samples compared to normal ovarian tissue samples was significantly correlated with worse overall survival. Additionally, Cox regression analysis suggested that NETO 1 was independently associated with overall survival. NETO1 overexpression enhanced the EOC cells’ migration and invasion capability in vitro via regulation of actin cytoskeleton. Mechanistically, silencing NETO1 reduced the expression of β‐tubulin, F‐actin and KIF2A. In conclusion, our results demonstrated the critical role of NETO1 in EOC invasion, and therapies aimed at inhibiting its expression or activity might significantly control EOC growth, invasion and metastatic dissemination.

Abstract B69: Gut microbiome attenuates epithelial ovarian cancer growth and sensitivity to cisplatin: New opportunities for ovarian cancer treatments

Abstract Epithelial ovarian cancer (EOC) is the second most common gynecologic malignancy in the United States, but the leading cause of gynecologic cancer death. Despite many women achieving remission with first-line therapy, which includes cytoreductive surgery and platinum-taxane chemotherapy, up to 80% of patients will recur and require additional treatment. The interval from last platinum chemotherapy to recurrence has important prognostic and therapeutic implications for patients. Patients with platinum-resistant EOC have fewer treatment options, worse prognosis, and their disease is seldom curable. Antibiotic therapy is frequently used during cancer treatments in patients with EOC for both prophylaxis and treatment of infections after surgery or through chemotherapy. While critical for the care of the patient, we now appreciate that the microbiome has many roles in maintenance of human health and is increasingly linked with many disease states including obesity, cardiovascular disease, and cancer. Recent evidence suggests the gut microbiome may modulate responses to cancer treatment, including traditional chemotherapy and immunotherapy. Given that antibiotics may lead to microbiome disruption for care of EOC patients and lack of understanding of the impact of these antibiotics on tumor progression, in preclinical models, we assessed the impact of microbiome disruption on EOC progression and cisplatin sensitivity. We established a necessary role for the microbiome in suppression of tumor growth and cisplatin response in two mouse models of EOC. Following treatment with antibiotics (ampicillin, neomycin, vancomycin, and metronidazole), murine ID8 or ID8-VEGF EOC that were injected intraperitoneally into C57Bl/6J mice exhibited accelerated tumor growth compared to non-antibiotic treated controls. Tumor growth was monitored by ultrasound weekly. ID8 and ID8-VEGF tumors in antibiotic-treated mice exhibited reduced sensitivity to cisplatin compared to non-antibiotic controls. Mice treated with antibiotics had significantly worse survival compared to non-antibiotic controls. We confirmed depletion of the gut microbiome based on dilated cecum and reduced microbial 16S rRNA concentration in stool of antibiotic-treated compared to control mice. The accelerated tumor growth and cisplatin resistance was not dependent on an intact immune system as we replicated the effect in immune-deficient mice. In mechanistic studies we determined that disruption of the microbiome led to increased cancer stem cells that was further augmented by cisplatin treatment. Collectively, these studies indicate an intact microbiome provides a tumor-suppressive microenvironment and enhances sensitivity to cisplatin. Future studies will assess whether individual microbial communities are sufficient to reverse the accelerated tumor growth and resistance to cisplatin observed in antibiotic-treated mice and use of selective antibiotics to target pathogenic bacteria while sparing beneficial microbes. Citation Format: Laura Chambers, Emily Esakov, Chad Braley, Leila Edelman, Roberto Vargas, Justin Lathia, Chad Michener, Ofer Reizes. Gut microbiome attenuates epithelial ovarian cancer growth and sensitivity to cisplatin: New opportunities for ovarian cancer treatments [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B69.

Current insights into the metastasis of epithelial ovarian cancer - hopes and hurdles.

Ovarian cancer is the most lethal gynecologic cancer and the fifth leading cause of cancer-related mortality in women worldwide. Despite various attempts to improve the diagnosis and therapy of ovarian cancer patients, the survival rate for these patients is still dismal, mainly because most of them are diagnosed at a late stage. Up to 90% of ovarian cancers arise from neoplastic transformation of ovarian surface epithelial cells, and are usually referred to as epithelial ovarian cancer (EOC). Unlike most human cancers, which are disseminated through blood-borne metastatic routes, EOC has traditionally been thought to be disseminated through direct migration of ovarian tumor cells to the peritoneal cavity and omentum via peritoneal fluid. It has recently been shown, however, that EOC can also be disseminated through blood-borne metastatic routes, challenging previous thoughts about ovarian cancer metastasis. Here, we review our current understanding of the most updated cellular and molecular mechanisms underlying EOC metastasis and discuss in more detail two main metastatic routes of EOC, i.e., transcoelomic metastasis and hematogenous metastasis. The emerging concept of blood-borne EOC metastasis has led to exploration of the significance of circulating tumor cells (CTCs) as novel and non-invasive prognostic markers in this daunting cancer. We also evaluate the role of tumor stroma, including cancer associated fibroblasts (CAFs), tumor associated macrophages (TAMs), endothelial cells, adipocytes, dendritic cells and extracellular matrix (ECM) components in EOC growth and metastasis. Lastly, we discuss therapeutic approaches for targeting EOC. Unraveling the mechanisms underlying EOC metastasis will open up avenues to the design of new therapeutic options. For instance, understanding the molecular mechanisms involved in the hematogenous metastasis of EOC, the biology of CTCs, and the detailed mechanisms through which EOC cells take advantage of stromal cells may help to find new opportunities for targeting EOC metastasis.