Immunological profiling of a panel of human ovarian cancer cell lines

The complex role of IL-10 in malignant ascites: a review

The emergence of malignant ascites (MA) indicates poor prognoses in patients with ovarian, gastrointestinal, breast, and pancreatic cancer. Interleukin-10 (IL-10) is a pleiotropic cytokine with immunoregulatory effects in tumor microenvironment. The level of IL-10 in MA varied across cancer types and patients, influencing cancer progression and outcomes. Originating from various immune and cancer cells, IL-10 contributes to complex signaling pathways in MA. Systemic IL-10 administration, although the evidence of its efficacy on MA is limited, still emerges as a promising therapeutic strategy because it can increase CD8+ T cells cytotoxicity and invigorate exhausted CD8+ tumor infiltration lymphocytes (TILs) directly. IL-10 signaling blockade also demonstrates great potential when combined with other immunotherapies in MA treatment. We reviewed the levels, origins, and functions of IL-10 in malignant ascites and overviewed the current IL-10 signaling targeting therapies, aiming to provide insights for MA treatment.

IL-10 Signaling in the Tumor Microenvironment of Ovarian Cancer

Unlike other malignancies, ovarian cancer (OC) creates a complex tumor microenvironment with distinctive peritoneal ascites consisting of a mixture of several immunosuppressive cells which impair the ability of the patient's immune system to fight the disease. The poor survival rates observed in advanced stage OC patients and the lack of effective conventional therapeutic options have been attributed in large part to the immature dendritic cells (DCs), IL-10 secreting regulatory T cells, tumor-associated macrophages, myeloid-derived suppressor cells, and cancer stem cells that secrete inhibitory cytokines. This review highlights the critical role played by the intraperitoneal presence of IL-10 in the generation of an immunosuppressive tumor microenvironment. Further, the effect of antibody neutralization of IL-10 on the efficacy of DC and chimeric antigen receptor T-cell vaccines will be discussed. Moreover, we will review the influence of IL-10 in the promotion of cancer stemness in concert with the NF-κB signaling pathway with regard to OC progression. Finally, understanding the role of IL-10 and its crosstalk with various cells in the ascitic fluid may contribute to the development of novel immunotherapeutic approaches with the potential to kill drug-resistant OC cells while minimizing toxic side effects.

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.

Human epithelial-type ovarian tumour marker beta-2-microglobulin is regulated by the TGF-β signaling pathway

Background

Beta-2-microglobulin (B2M), a light chain subunit of the major histocompatibility complex (MHC) class I complex, has been implicated in tumorigenesis. However, whether it is expressed in different epithelial-type ovarian tumours remains unknown. This study was performed to examine the expression of B2M in different histopathological types of ovarian tumours, to explore the function of B2M in ovarian cancer (OC) cells and to investigate the mechanisms underlying the regulation of B2M by the TGF-β signaling pathway.

Methods

B2M expression in normal ovarian tissues and epithelia-type ovarian tumours was detected by immunohistochemistry and Western blot, followed by the analysis of association with clinical features. OC cells were transfected with B2M-siRNA and cell proliferation, migration and invasion were determined by WST-1 assay, wound healing assay and Transwell invasion assay, respectively. The regulation of B2M by the TGF-β signaling pathway in OC cells was examined by Western blot, ELISA and qRT-PCR.

Results

We found that B2M was overexpressed in ovarian borderline and malignant tumours compared with benign tumours and normal controls, but was not associated with age, tumour size, lymph node metastasis and clinical stage. Knocking down of B2M led to a decrease in OC cell proliferation, migration and invasion. The expression of B2M was downregulated by TGF-β1 in OC cells, which was abolished in the presence of the inhibitor of TGF-β type I receptor.

Conclusion

Our findings suggest that B2M is a potential tissue biomarker and therapeutic target of borderline and malignant ovarian tumours and the dysregulation of B2M in these tumours may be mediated by the TGF-β signaling pathway.

Efficient lysis of epithelial ovarian cancer cells by MAGE-A3-induced cytotoxic T lymphocytes using rAAV-6 capsid mutant vector

MAGE-A3 is highly expressed in epithelial ovarian cancer (EOC), making it a promising candidate for immunotherapy. We investigated whether dendritic cells (DCs) transduced with a rAAV-6 capsid mutant vector Y445F could elicit effective MAGE-A3-specific anti-tumor cytotoxic T lymphocyte (CTL) responses in vitro. MAGE-A3 was cloned and rAAV-6-MAGE-A3 purified, followed by proviral genome detection using real-time PCR. Immunofluorescence detection of rAAV-6-Y445F-MAGE-A3-transduced DCs demonstrated 60% transduction efficiency. Fluorescent in situ hybridization analysis confirmed chromosomal integration of rAAV vectors. Flow cytometric analysis of transduced DCs showed unaltered expression of critical monocyte-derived surface molecules with retention of allo-stimulatory activity. Co-culture of autologous T lymphocytes with MAGE-A3-expressing DCs produced CTLs that secreted IFN-γ, and efficiently killed MAGE-A3+ EOC cells. This form of rAAV-based DC immunotherapy, either alone or more likely in combination with other immune-enhancing protocols, may prove useful in the clinical setting for management of EOC.

Immune response evaluation through determination of type 1, type 2, and type 17 patterns in patients with epithelial ovarian cancer

Innate and adaptive immune cells secrete different cytokines, which participate through distinct mechanisms in cell-mediated immunity and humoral immune responses. The aim of this study was to evaluate the immune response through analysis of type 1 (Th1), Th2, and Th17 cells in patients with epithelial ovarian cancer (EOC). Our study included 44 patients with EOC (study group) and 32 gynecological patients with no ovarian disease (control group). Fragments of ovarian tissue and blood samples were collected in both groups and aliquots of intracystic fluid and peritoneal fluid were recovered from the EOC patient group. Interleukin (IL)-2/IL-4/IL-6/IL-10/IL-17/tumor necrosis factor (TNF)-α/interferon (IFN)-γ levels were measured by cytometric bead array. Statistical analysis included chi-squared, Student t, Mann-Whitney, Kruskal-Wallis tests, and Cox regression model. Patients with EOC were associated with higher levels of TNF-α/IL-4/IL-6/IL-10 compared to the control group. Both IL-10 and TNF-α concentrations were higher in patients with stage III/IV EOC and also associated with higher levels of cancer antigen 125. Higher Th1-mediated immune response was observed when the cytoreduction was considered optimal. However, patients with EOC with unsatisfactory cytoreductive surgery and undifferentiated tumors were associated with higher concentrations of Th2 cytokines in the 4 sites studied. Higher IL-6/IL-10 and lower IFN-γ concentrations were also associated with a lower overall survival rate in patients with EOC. The EOC group presented a predominantly Th2 response and an immunosuppressant standard and had association between IL-6/IL-10/IFN-γ and prognosis.

IL-10 immunomodulation of myeloid cells regulates a murine model of ovarian cancer

Elevated levels of IL-10 in the microenvironment of human ovarian cancer and murine models of ovarian cancer are well established and correlate with poor clinical prognosis. However, amongst a myriad of immunosuppressive factors, the actual contribution of IL-10 to the ovarian tumor microenvironment, the mechanisms by which it acts, and its possible functional redundancy are unknown. We previously demonstrated that elimination of the myeloid-derived suppressor cell (MDSC) compartment within the ovarian tumor ascites inhibited tumor progression and, intriguingly, significantly decreased local IL-10 levels. Here we identify a novel pathway in which the tumor-infiltrating MDSC are the predominant producers of IL-10 and, importantly, require it to develop their immunosuppressive function in vivo. Importantly, we demonstrate that the role of IL-10 is critical, and not redundant with other immunosuppressive molecules, to in vivo tumor progression: blockade of the IL-10 signaling network results in alleviation of MDSC-mediated immunosuppression, altered T cell phenotype and activity, and improved survival. These studies define IL-10 as a fundamental modulator of both MDSC and T cells within the ovarian tumor microenvironment. Importantly, IL-10 signaling is shown to be necessary to the development and maintenance of a permissive tumor microenvironment and represents a viable target for anti-tumor strategies.

Chemotherapeutic effects of bioassay-guided extracts of the American cockroach, Periplaneta americana

The organic extract of Periplaneta americana L. (Dictyoptera; Blattidae) has been traditionally used in southwestern China as an alternative medicine against disorders such as hepatitis, trauma, gastric ulcers, burns, and heart disease. The present study describes bioassay-guided purification and chemotherapeutic evaluation of the 60% ethanolic fraction of P americana organic extracts (PAE60). The most effective cytotoxic fraction was determined by way of repeated in vitro screenings against 12 distinct cultured human carcinoma cell lines: Eca 109, BGC823, HO8910, LS174T, CNE, HeLa, K562, PC-3, A549, BEL 7404, HL-60, and KB, followed by in vivo antitumor assays of the lead fraction (PAE60). The complexity of enriched active fraction was qualitatively evaluated using thin layer chromatography. Reconstituted PAE60 was effective at inhibiting HL-60, KB, CNE, and BGC823 cell growth with IC(50) values <20 µg mL-(1). PAE60 reduced tumor growth in S180-bearing immunocompetent mice by 72.62% after 10 days following oral doses of 500 mg kg d-(1) compared with 78.75% inhibition following 40 mg kg d-(1) of cyclophosphamide (CTX). Thymus and spleen indices of S180-bearing mice treated with PAE60 were significantly greater (P < .05) than CTX treatment groups, suggesting potential immunomodulation of antitumor host defenses by PAE60. Antiviral activity was also investigated and PAE60 inhibited herpes simplex type-2 replication (IC(50) = 4.11 ± 0.64 µg mL-(1)) with a selectivity index (CC(50) to IC(50) ratio) of 64.84 in Vero cells but was less effective on type-1 virus (IC(50) of 25.6 ± 3.16 µg mL-(1)). These results support future clinical trials on P. americana as an alternative or complementary medicinal agent.

Treatment of ovarian cancer cell lines with 5-aza-2'-deoxycytidine upregulates the expression of cancer-testis antigens and class I major histocompatibility complex-encoded molecules

PURPOSE

To test the hypothesis that decrease in DNA methylation will increase the expression of cancer-testis antigens (CTA) and class I major histocompatibility complex (MHC)-encoded molecules by ovarian cancer cells, and thus increase the ability of these cells to be recognized by antigen-reactive CD8(+) T cells.

METHODS

Human ovarian cancer cell lines were cultured in the presence or absence of varying concentrations of the DNA demethylating agent 5-aza-2'-deoxycytidine (DAC) for 3-7 days. The expression levels of 12 CTA genes were measured using the polymerase chain reaction. The protein expression levels of class I MHC molecules and MAGE-A1 were measured by flow cytometry. T cell reactivity was determined using interferon-gamma ELISpot analysis.

RESULTS

DAC treatment of ovarian cancer cell lines increased the expression of 11 of 12 CTA genes tested including MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A6, MAGE-A10, MAGE-A12, NY-ESO-1, TAG-1, TAG-2a, TAG-2b, and TAG-2c. In contrast, DAC treatment decreased the already low expression of the MAGE-A2 gene by ovarian cancer cells, a finding not previously observed in cancers of any histological type. DAC treatment increases the expression of class I MHC molecules by the cells. These effects were time-dependent over a 7-day interval, and were dose-dependent up to 1-3 microM for CTA and up to 10 microM for class I MHC molecules. Each cell line tested had a unique pattern of gene upregulation after exposure to DAC. The enhanced expression levels increased the recognition of 2 of 3 antigens recognized by antigen-reactive CD8(+) T cells.

CONCLUSIONS

These results demonstrate the potential utility of combining DAC therapy with vaccine therapy in an attempt to induce the expression of antigens targeted by the vaccine, but they also demonstrate that care must be taken to target inducible antigens.

Generation and regulation of human CD4+ IL-17-producing T cells in ovarian cancer

Despite the important role of Th17 cells in the pathogenesis of many autoimmune diseases, their prevalence and the mechanisms by which they are generated and regulated in cancer remain unclear. Here, we report the presence of a high percentage of CD4(+) Th17 cells at sites of ovarian cancer, compared with a low percentage of Th17 cells in peripheral blood mononuclear cells from healthy donors and cancer patients. Analysis of cytokine production profiles revealed that ovarian tumor cells, tumor-derived fibroblasts, and antigen-presenting cells (APCs) secreted several key cytokines including IL-1beta, IL-6, TNF-alpha and TGF-beta, which formed a cytokine milieu that regulated and expanded human IL-17-producing T-helper (Th17) cells. We further show that IL-1beta was critically required for the differentiation and expansion of human Th17 cells, whereas IL-6 and IL-23 may also play a role in the expansion of memory Th17 cells, even though IL-23 levels are low or undetectable in ovarian cancer. Further experiments demonstrated that coculture of naïve or memory CD4(+) T cells with tumor cells, APCs, or both could generate high percentages of Th17 cells. Treatment with anti-IL-1 alone or a combination of anti-IL-1 and anti-IL-6 reduced the ability of tumor cells to expand memory Th17 cells. Thus, we have identified a set of key cytokines secreted by ovarian tumor cells and tumor-associated APCs that favor the generation and expansion of human Th17 cells. These findings should accelerate efforts to define the function of this important subset of CD4(+) T cells in the human immune response to cancer.

Genomic and proteomic characterization of YDOV-157, a newly established human epithelial ovarian cancer cell line

The existence of several model systems with which to investigate a particular disease is advantageous for researchers. This is especially true for ovarian cancer, which, due to its complex and heterogeneous nature, inherently requires a large number of model systems. Here, we report a new ovarian serous adenocarcinoma cell line, designated YDOV-157, and characterized via post genomics and post proteomics. In this study, primary culture of tumor cells from ascites was performed and the cells were immortalized up to at least 60 passages in vitro. We studied the morphologies, cell proliferation, BRCA1/2 mutations, tumorigenesis capacity, and chemosensitivity of YDOV-157. Using a cDNA microarray, differentially expressed genes were identified and some of them were validated. Using proteomic analysis, we identified proteins that were differentially expressed in YDOV-157. The newly derived cell line, designated YDOV-157, grew as a monolayer and the doubling time was 102 h. When transplanted into nude mice, it initiated the formation of tumor masses with microscopic findings identical to those of the primary tumor. Chemosensitivity test showed that paclitaxel induced the highest chemosensitivity index. In microarray analysis, 2,520 probes were differently expressed, compared to human ovarian surface epithelial cells (HOSEs). In SYBR Green real-time PCR, the expression of E2F2 (P = 0.040) and CRABP2 genes (P = 0.030) was significantly higher in the ovarian cancer cell lines than in HOSEs. Furthermore, proteomic analysis showed that expression of 28 spots was significantly altered between YDOV-157 and HOSE. In conclusion, the newly derived YDOV-157 cell line may be an important research resource for studying cancer cell biology and should also be very useful for developing new strategies that inhibit cancer cell growth and progression.