Ovarian cancer biology and immunotherapy

Tumor microenvironment and cellular senescence: Understanding therapeutic resistance and harnessing strategies

The tumor microenvironment (TME) is a major contributor to cancer malignancy including development of therapeutic resistance, a process mediated in part through intercellular crosstalk. Besides diverse soluble factors responsible for pro-survival pathway activation, immune evasion and extracellular matrix (ECM) remodeling further promote cancer resistance. Importantly, therapy-induced senescence (TIS) of cells in the TME is frequently observed in anticancer regimens, an off-target effect that can generate profound impacts on disease progression. By conferring the resistance and fueling the repopulation of remaining cancerous cells, TIS is responsible for tumor relapse and distant metastasis in posttreatment stage. This pathological trajectory can be substantially driven by the pro-inflammatory feature of senescent cells, termed as the senescence-associated secretory phenotype (SASP). Targeting strategies to selectively and efficiently remove senescent cells before they exert non-autonomous but largely deleterious effects, are emerging as an effective solution to prevent drug resistance acquired from a treatment-remodeled TME. In this review, we summarize the TME composition and key activities that affect tissue homeostasis and support treatment resistance. Promising opportunities that allow TME-manipulation and senescent cell-targeting (senotherapy) are discussed, with translational pipelines to overcome therapeutic barriers in clinical oncology projected.

Long non-coding RNA SNHG12 promotes immune escape of ovarian cancer cells through their crosstalk with M2 macrophages

Accumulating evidence shows that the tumor microenvironment contributes to this phenomenon and that long non-coding RNAs (lncRNAs) are also involved in this process. In this study, we identified a new lncRNA small nucleolar RNA host gene 12 (SNHG12) and investigated its role in tumor immune escape. We analyzed the expression levels of interlukin (IL)-6R and programmed death-ligand 1 (PD-L1) in 51 ovarian cancer and 20 normal specimens by immunohistochemistry. The correlation between SNHG12 and IL-6R in clinical ovarian cancer samples was identified by RT-qPCR. We then performed SNHG12 gain- and loss-function experiments in order to investigate its role in the regulation of immune escape and the crosstalk between miR-21 and IL-6. T cell proliferation was assessed by flow cytometry. In vivo pro-immune escape activity of SNHG12 was assessed by tumor-xenograft mouse model. IL-6R and PD-L1 were found to be overexpressed in clinical ovarian cancer specimens. Meanwhile, SNHG12 and IL-6R expressions were positively correlated in clinical ovarian cancer samples. SNHG12 facilitated ovarian immune escape by promoting IL-6/miR-21 crosstalk between ovarian cancer cells and M2 macrophages. Notably, SNHG12 promoted IL-6R transcription by recruiting NF-κB1 to the IL-6R promoter. Our study reveals that SNHG12 facilitates ovarian cancer immune escape by upregulating IL-6R.

Immune mediator expression signatures are associated with improved outcome in ovarian carcinoma

Immune and inflammatory cascades may play multiple roles in ovarian cancer. We aimed to identify relationships between expression of immune and inflammatory mediators and patient outcomes. We interrogated differential gene expression of 44 markers and marker combinations (n = 1,978) in 1,656 ovarian carcinoma patient tumors, alongside matched 5-year overall survival (OS) data in silico. Using machine learning methods, we investigated whether genomic expression of these 44 mediators can discriminate between malignant and non-malignant tissues in 839 ovarian cancer and 115 non-malignant ovary samples. We furthermore assessed inflammation markers in 289 ovarian cancer patients’ sera in the Swedish Apolipoprotein MOrtality-related RISk (AMORIS) cohort. Expression of the 44 mediators could discriminate between malignant and non-malignant tissues with at least 96% accuracy. Higher expression of classical Th1, Th2, Th17, anti-parasitic/infection and M1 macrophage mediator signatures were associated with better OS. Contrastingly, inflammatory and angiogenic mediators, CXCL-12, C-reactive protein (CRP) and platelet-derived growth factor subunit A (PDGFA) were negatively associated with OS. Of the serum inflammatory markers in the AMORIS cohort, women with ovarian cancer who had elevated levels of haptoglobin (≥1.4 g/L) had a higher risk of dying from ovarian cancer compared to those with haptoglobin levels <1.4 g/L (HR = 2.09, 95% CI:1.38–3.16). Our findings indicate that elevated “classical” immune mediators, associated with response to pathogen antigen challenge, may confer immunological advantage in ovarian cancer, while inflammatory markers appear to have negative prognostic value. These highlight associations between immune protection, inflammation and clinical outcomes, and offer opportunities for patient stratification based on secretome markers.

Harnessing Liposome Interactions With the Immune System for the Next Breakthrough in Cancer Drug Delivery

Liposomal nanoparticles are a heterogeneous group of engineered drug carriers that have tremendous therapeutic potential in the treatment of cancer. They increase tumor drug delivery, significantly attenuate drug toxicity, and protect the drug from degradation. However, two decades after approval of the first nanoparticle-mediated anticancer drug, pegylated liposomal doxorubicin (Doxil), there has yet to be a major shift in cancer treatment paradigms. Only two anticancer nanoparticles are used in the first-line treatment of cancer patients, with all others relegated to the refractory or salvage setting. Herein, we discuss new insights into the mechanisms underlying in vivo interactions between liposomes and the tumor immunologic milieu, and the knowledge gaps that need to be addressed in order to realize the full clinical potential of cancer nanomedicines. We also discuss immunopharmacology insights from a parallel field, Cancer Immunotherapy, which have the potential to generate breakthroughs in Cancer Nanomedicine.

Inhibition of Ca2+ -activated chloride channel ANO1 suppresses ovarian cancer through inactivating PI3K/Akt signaling

Most common ovarian cancers are epithelial carcinoma in which the etiology for carcinogenesis remains elusive. ANO1/TMEM16A, a member of Ca²⁺ -activated Cl^- channels (CaCCs), has been demonstrated to promote epithelium-originated cancers and whether it plays a role in the pathogenesis of ovarian cancer is unknown. In our study we found that ANO1 proteins were overexpressed in human epithelial ovarian cancer cells and tissue samples. ANO1 protein upregulation was correlated with the clinical FIGO (International Federation of Gynecology and Obstetrics) staging and poor grade in ovarian cancer tissues. Interestingly, the upregulation of ANO1 gene expression was also detected in the peripheral blood mononuclear cells (PBMCs) from preoperative patients with ovarian tumors, and the down-regulation of ANO1 in the PBMCs from postoperative patients. Silencing of ANO1 inhibited proliferation and invasion of ovarian cancer cells. Mechanistically, ANO1 knockdown attenuated phosphorylation of PI3K/Akt, and inhibition of PI3K/Akt signaling by specific inhibitor LY294002 resulted in suppression of ovarian cancer cells growth promoted by ANO1 expression. Furthermore, intratumoral injection of ANO1 siRNA suppressed subcutaneous xenograft tumor growth in nude mice implanted with ovarian cancer SKOV3 cells. Taken together, our findings demonstrate that ANO1 overexpression is involved in the pathogenesis of human epithelial ovarian cancer. Inhibition of ANO1 upregulation or inactivating PI3K/Akt signaling may have therapeutic potential for epithelial ovarian cancer, and the detection of ANO1 expression level in PBMCs from patients may also serve as a biomarker for diagnosis and prognosis of epithelial ovarian cancers.

Methylseleninic Acid Sensitizes Ovarian Cancer Cells to T-Cell Mediated Killing by Decreasing PDL1 and VEGF Levels

Redox active selenium (Se) compounds at sub toxic doses act as pro-oxidants with cytotoxic effects on tumor cells and are promising future chemotherapeutic agents. However, little is known about how Se compounds affect immune cells in the tumor microenvironment. We demonstrate that the inorganic Se compound selenite and the organic methylseleninic acid (MSA) do not, despite their pro-oxidant function, influence the viability of immune cells, at doses that gives cytotoxic effects in ovarian cancer cell lines. Treatment of the ovarian cancer cell line A2780 with selenite and MSA increases NK cell mediated lysis, and enhances the cytolytic activity of T cells. Increased T cell function was observed after incubation of T cells in preconditioned media from tumor cells treated with MSA, an effect that was coupled to decreased levels of PDL1, HIF-1α, and VEGF. In conclusion, redox active selenium compounds do not kill or inactivate immune cells at doses required for anti-cancer treatment, and we demonstrate that MSA enhances T cell-mediated tumor cell killing via PDL1 and VEGF inhibition.

Plasma and ovarian tissue sphingolipids profiling in patients with advanced ovarian cancer

PURPOSE

The role of lipids in carcinogenesis through induction of abnormal cell lines in the human body is currently undisputable. Based on the literature, bioactive sphingolipids play an essential role in the development and progression of cancer and are involved in the metastatic process. The aim of this study was to determine the concentration of selected sphingolipids in patients with advanced ovarian cancer (AOC, FIGO III/IV, high grade ovarian cancer).

METHODS

Seventy-four patients with ovarian cancer were enrolled. Plasma concentrations of C16-Cer, C18:1-Cer and C18-Cer were assessed by LC/MS/MS. The content of tissue sphingolipids was measured using a UHPLC/MS/MS.

RESULTS

Plasma concentration of 3 ceramides: C16-Cer, C18:1-Cer and C18-Cer was significantly elevated in women with advanced ovarian cancer compared to control group (P=0.031; 0.022; 0.020; respectively). There were increases in concentration of 5 ceramides: C16-Cer, C18:1-Cer, C18-Cer, C24:1-Cer, C24-Cer (P=0.025; 0.049; 0.032; 0.005; 0.013, respectively) and S1P (P=0.004) in ovarian tissue of women with advanced ovarian cancer compared to healthy individuals. Importantly, significantly higher risk of ovarian cancer when the plasma concentration of C16-Cer>311.88ng/100μl (AUC: 0.76, P=0.0261); C18:1-Cer>4.75ng/100μl (AUC: 0.77, P=0.0160) and C18-Cer>100.76ng/100μl (AUC:0.77, P=0.0136) was noticed.

CONCLUSIONS

Bioactive sphingolipids play an essential role in the development and progression of cancer and they also take part in the process of metastasizing. This study suggests that some sphingolipids can be used as potential biomarkers of advanced ovarian cancer and that they can play an important role in the pathogenesis of this disease.

Influence of ovarian cancer type I and type II microenvironment on the phenotype and function of monocyte-derived dendritic cells

PURPOSE

The aim of this study was to evaluate the influence of ovarian cancer cell lysates isolated from type I or type II ovarian cancer (OC) on the phenotype of monocyte-derived dendritic cells (Mo-DCs) and the cytokine profile. We also determined whether the Mo-DCs and tumor microenvironment, reflected by peritoneal fluid (PF) from type I or II ovarian cancer, could promote regulatory T cell (Tregs) differentiation from naive CD4⁺ lymphocytes in vitro.

RESULTS

Our results show a significant role of the ovarian cancer microenvironment reflected by PF from type I or II OC in the inhibition of the DC differentiation process. Interestingly, the percentage of cells co-expressing CD45 and CD14 antigens in the cultures stimulated with PF from both type I and type II OC was higher than in the control. Furthermore, the percentage of cells expressing CD1a, i.e., a marker of immature DCs, was significantly reduced in the cultures stimulated with PF from type I and type II OC. The results obtained show that ovarian cancer type II lysates induce differentiation of monocytes into macrophage-like cells with a CD1a⁺/HLA-DR⁺/CD83⁻ phenotype and significantly higher CD86/HLA-DR expression. We show that ovarian cancer type II Mo-DCs are able to prevent an immune response by release of IL-10, whereas OC type I Mo-DCs can promote the generation of Tregs.

CONCLUSIONS

We demonstrate that each type of ovarian cancer can induce a unique phenotype of DCs and differentiation of Tregs, both associated with immune-suppressive function, which may be an obstacle while developing effective anticancer dendritic cell vaccination.

miR-762 can negatively regulate menin in ovarian cancer

Ovarian cancer accounts for the major part of the mortality attributable to female reproductive system malignant tumors worldwide. Recently, the incidence of ovarian cancer has been increasing annually, and there remains a lack of suitable treatment methods that can significantly improve the 5-year survival rates of patients. Therefore, it is necessary to identify more effective treatments for ovarian cancer. It is established that microRNAs (miRNAs) have important roles in the diagnosis and treatment of ovarian cancer and a specific miRNA, miR-762, can promote the development of a variety of tumors. Menin is encoded by MEN1, a tumor suppressor gene, that is usually downregulated in ovarian cancer. In this study, we evaluated the expression levels of miR-762 and menin in ovarian cancer tissues and demonstrated that they were correlated. In addition, we found that miR-762 can downregulate the expression of menin through a binding site in its 3′-UTR and consequently upregulate the Wnt cell signaling pathway to promote the development of ovarian cancer. These results indicate that miR-762 is a promising potential target for the treatment of ovarian cancer.

Comparative assessment of lipid based nano-carrier systems for dendritic cell based targeting of tumor re-initiating cells in gynecological cancers

We aimed to identify an optimum nano-carrier system to deliver tumor antigen to dendritic cells (DCs) for efficient targeting of tumor reinitiating cells (TRICs) in gynecological malignancies. Different lipid based nano-carrier systems i.e. liposomes, ethosomes and solid lipid nanoparticles (SLNPs) were examined for their ability to activate DCs in allogeneic settings. Out of these three, the most optimized formulation was subjected for cationic and mannosylated surface modification and pulsed with DCs for specific targeting of tumor cells. In both allogeneic and autologous trials, SLNPs showed a strong ability to activate DCs and orchestrate specific immune responses for targeting TRICs in gynecological malignancies. Our findings suggest that the mannosylated form of SLNPs is a suitable molecular vector for DC based therapeutics. DCs pulsed with mannosylated SLNPs may be utilized as adjuvant therapy for specific removal of TRICs to benefit patients from tumor recurrence.

Gene expression profiling of CD8+ T cells induced by ovarian cancer cells suggests a possible mechanism for CD8+ Treg cell production

OBJECTIVES

The aim of this study was to investigate a possible mechanism of CD8⁺ regulatory T-cell (Treg) production in an ovarian cancer (OC) microenvironment.

MATERIALS AND METHODS

Agilent microarray was used to detect changes in gene expression between CD8⁺ T cells cultured with and without the SKOV3 ovarian adenocarcinoma cell line. QRT-PCR was performed to determine glycolysis gene expression in CD8⁺ T cells from a transwell culturing system and OC patients. We also detected protein levels of glycolysis-related genes using Western blot analysis.

RESULTS

Comparing gene expression profiles revealed significant differences in expression levels of 1420 genes, of which 246 were up-regulated and 1174 were down-regulated. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis indicated that biological processes altered in CD8⁺ Treg are particularly associated with energy metabolism. CD8⁺ Treg cells induced by co-culture with SKOV3 had lower glycolysis gene expression compared to CD8⁺ T cells cultured alone. Glycolysis gene expression was also decreased in the CD8⁺ T cells of OC patients.

CONCLUSIONS

These findings provide a comprehensive bioinformatics analysis of DEGs in CD8⁺ T cells cultured with and without SKOV3 and suggests that metabolic processes may be a possible mechanism for CD8⁺ Treg induction.

Atractylenolide I modulates ovarian cancer cell-mediated immunosuppression by blocking MD-2/TLR4 complex-mediated MyD88/NF-κB signaling in vitro

BACKGROUND

TLR4/MD-2 complex-mediated MyD88-dependent activation of NF-κB and Akt promotes tumor-associated immunosuppression in epithelial ovarian cancer (EOC) via induction of immunesuppressive cytokines and indoleamine 2,3-dioxygenase (IDO). Atractylenolide I (AO-1) is a naturally occurring sesquiterpene lactone known to change the conformational ensemble of human MD-2 on EOC cells. This study examined the modulation by AO-1 of TLR4/MD-2 complex-mediated MyD88/NF-κB signaling.

METHODS

The expression and activation of NF-κB, Akt and IDO1 by MyD88(+) EOC SKOV3 cells was determined using western blot; the TLR4/MD-2 complex on SKOV3 cells and the phenotype of T lymphocytes were determined using flow cytometry; IDO activity was evaluated by measuring L-kynurenine; Immunesuppressive cytokines were detected using ELISA; T-cell proliferation to mitogen stimulation was assessed by MTT assay; the cytotoxicity of lymphocytes and NK cells was measured using LDH-cytotoxicity assay.

RESULTS

AO-1 could down-regulate expression of TLR4/MD-2 complex, resulting in downregulation of MyD88/NF-κB signaling and activation of NF-κB, Akt and IDO1 and secretion of IL-6, TGF-β1, VEGF and IL-17A by EOC SKOV3 cells, and further reduce increased levels of regulatory T cells (Treg cells) and improve decreased proliferative response and antitumor cytotoxicity of T lymphocytes exposed to EOC SKOV3 cell supernatant.

CONCLUSION

AO-1 may reverse EOC cell-mediated immunosuppression through blocking TLR4/MD-2 complex-mediated MyD88/NF-κB signaling.

Targeting the hallmarks of ovarian cancer: The big picture

OBJECTIVE

As a result of relevant achievements in the field of translational research, several active drugs and multiple biological targets are available in ovarian cancer (OC). In this complex scenario, there is an urgent need to effectively summarize the available data in order to update conclusions, and outline perspectives.

METHODS

The results in terms of target identification and drug development have been summarized using the well-known hallmarks of cancer firstly described, and recently modified by Hanahan and Weinberg [1-2]. Published data from clinical trials have been retrieved from PubMed, Embase, CINAHL and Cochrane database. Ongoing clinical trials were searched using clinicaltrials.gov web platform, and identified using NCT number.

RESULTS

Genomic instability and angiogenesis are the most actively investigated hallmarks in high-grade serous OC, and the inhibition of tumor immune evasion appears as the emerging strategy for molecularly-driven therapy. Targeting sustained proliferative signaling through MEK and mTOR inhibitors seems the most promising approach in clear cell, and low-grade serous OC.

CONCLUSIONS

This substantial amount of data suggests that targeted therapies are already part of the clinical and therapeutic management of OC patients. The expectations of getting from translational research a better knowledge of tumor biology and therefore personalized drugs are high and worthy of maximum effort from referral centers.

IL17a and IL21 combined with surgical status predict the outcome of ovarian cancer patients

Aside from tumor cells, ovarian cancer-related ascites contains the immune components. The aim of this study was to evaluate whether a combination of clinical and immunological parameters can predict survival in patients with ovarian cancer. Ascites specimens and medical records from 144 ovarian cancer patients at our hospital were used as the derivation group to select target clinical and immunological factors to generate a risk-scoring system to predict patient survival. Eighty-two cases from another hospital were used as the validation group to evaluate this system. The surgical status and expression levels of interleukin 17a (IL17a) and IL21 in ascites were selected for the risk-scoring system in the derivation group. The areas under the receiver operating characteristic (AUROC) curves of the overall score for disease-free survival (DFS) of the ovarian cancer patients were 0.84 in the derivation group, 0.85 in the validation group, and 0.84 for all the patients. The AUROC curves of the overall score for overall survival (OS) of cases were 0.78 in the derivation group, 0.76 in the validation group, and 0.76 for all the studied patients. Good correlations between overall risk score and survival of the ovarian cancer patients were demonstrated by sub-grouping all participants into four groups (P for trend <0.001 for DFS and OS). Therefore, acombination of clinical and immunological parameters can provide a practical scoring system to predict the survival of patients with ovarian carcinoma. IL17a and IL21 can potentially be used as prognostic and therapeutic biomarkers.

γδ T Cell-Mediated Immune Responses in Disease and Therapy

The role of γδ T cells in immunotherapy has gained specific importance in the recent years because of their prominent function involving directly or indirectly in the rehabilitation of the diseases. γδ T cells represent a minor population of T cells that express a distinct T cell receptor (TCR) composed of γδ chains instead of αβ chains. Unlike αβ T cells, γδ T cells display a restricted TCR repertoire and recognize mostly unknown non-peptide antigens. γδ T cells act as a link between innate and adaptive immunity, because they lack precise major histocompatibility complex (MHC) restriction and seize the ability to recognize ligands that are generated during affliction. Skin epidermal γδ T cells recognize antigen expressed by damaged or stressed keratinocytes and play an indispensable role in tissue homeostasis and repair through secretion of distinct growth factors. γδ T cell based immunotherapy strategies possess great prominence in the treatment because of the property of their MHC-independent cytotoxicity, copious amount of cytokine release, and a immediate response in infections. Understanding the role of γδ T cells in pathogenic infections, wound healing, autoimmune diseases, and cancer might provide knowledge for the successful treatment of these diseases using γδ T cell based immunotherapy. Enhancing the human Vγ9Vδ2 T cells functions by administration of aminobisphosphonates like zoledronate, pamidronate, and bromohydrin pyrophosphate along with cytokines and monoclonal antibodies shows a hopeful approach for treatment of tumors and infections. The current review summarizes the role of γδ T cells in various human diseases and immunotherapeutic approaches using γδ T cells.

Clinically relevant microRNAs in ovarian cancer

microRNAs (miRNAs/miRs) belong to a class of small noncoding RNAs that can negatively regulate messenger RNA (mRNA) expression of target genes. miRNAs are involved in multiple aspects of ovarian cancer cell dysfunction and the phenotype of ovarian cancer cells can be modified by targeting miRNA expression. miRNA profiling has detected a number of candidate miRNAs with the potential to regulate many important biologic functions in ovarian cancer, but their role still needs to be clarified, given the remarkable heterogeneity among ovarian cancers and the context-dependent role of miRNAs. This review summarizes the data collected from The Cancer Genome Atlas (TCGA) and several other genome-wide projects to identify dysregulated miRNAs in ovarian cancers. Copy number variations (CNVs), epigenetic alterations, and oncogenic mutations are also discussed that affect miRNA levels in ovarian disease. Emphasis is given to the role of particular miRNAs in altering expression of genes in human ovarian cancers with the potential to provide diagnostic, prognostic, and therapeutic targets. Particular attention has been given to TP53, BRCA1/2, CA125 (MUC16), HE4 (WFDC2), and imprinted genes such as ARHI (DIRAS3). A better understanding of the abnormalities in miRNA expression and downstream transcriptional and biologic consequences will provide leads for more effective biomarkers and translational approaches in the management of ovarian cancer.

Dynamic analysis of tumor-associated immune cells in DEN-induced rat hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive disease with poor prognosis and limited methods to predict patient survival. Immune cells infiltrating tumors are known to impact tumor progression. Here, we analyzed the phenotype and function of dendritic cells (DCs), and the frequency of IL-10-producing regulatory B cells (Breg) and Foxp3(+) regulatory T cells (Treg) in different stages of N-nitrosodiethylamine (DEN)-induced rat HCC in order to understand their roles in this disease. 4weeks following DEN treatment, no significant differences in CD80 and CD86 expression were found on DCs from HCC rats and normal rats but 12 and 16weeks following DEN treatment, the expression of CD80, CD86 and MHCII on DCs of HCC rats was significantly decreased. We also found that the frequency of IL-10-producing Breg and CD4(+)CD25(+)Foxp3(+) Treg in HCC rats was obviously increased during all of these three stages. In addition, the bone-marrow derived DCs (BMDCs) from HCC rats displayed lower ability in activating T cells and an increase in IL-10 secretion. No differences in IL-12 level and endocytosis ability were found on BMDCs from HCC rats and normal rats. Our results suggest that the dysfunction of DCs and the increase of IL-10-producing Breg and Foxp3(+) Treg might play important roles in HCC progression.