T cell infiltration and MHC I and II expression in the presence of tumor antigens: An immunohistochemical study in patients with serous epithelial ovarian cancer

Advances of exosome in the development of ovarian cancer and its diagnostic and therapeutic prospect

Ovarian cancer is the leading cause of female gynecological cancer mortality. Most patients with ovarian cancer are diagnosed with advanced stage because of lack of early symptoms, physical signs, and sensitive tumor biomarkers. The standard treatment includes cytoreductive surgery and platinum-based chemotherapy (usually platinum combined with paclitaxel). Despite that postoperative adjuvant chemotherapy prolongs survival time, most patients go through relapse within 6–12 months after the treatment. Thus, elucidating the molecular mechanism in cancer development is essential to promote early diagnosis and novel treatments. The role of exosome has been highlighted in multiple research fields in recent years. Exosome has been described as nano-sized vesicle secreted by multiple mammalian cell types, carrying cargos like proteins, miRNAs, mRNAs, and lipids. It participates in the formation of tumor microenvironment and the development of tumorigenesis and drug resistance in ovarian cancer. Meanwhile, it may also play a pivotal role in diagnosis, efficacy evaluation, and prognosis. Besides, studies show that exosome and its processed products have promising value in ovarian cancer treatment. The aim of the current review is to describe the characteristics of exosome in ovarian cancer, especially focusing on its role in immune modulation and drug resistance, hoping to provide new information on its implications in cancer diagnosis and treatment.

NLRC5 expression in tumors and its role as a negative prognostic indicator in stage III non-small-cell lung cancer patients

Major histocompatibility complex (MHC) class I molecules have a crucial role in tumor immune evasion; however, the association of MHC class I molecules with outcomes in cancer patients remains controversial. Nucleotide-binding oligomerization-like receptor family caspase recruitment domain-containing 5 (NLRC5) has been reported to be a MHC class I transactivator. However, the expression and function of NLRC5 in cancer remains to be elucidated. The present study aimed to retrospectively examine NLRC5 expression in human tumor tissues and its association with clinical outcomes of non-small-cell lung cancer (NSCLC) stage III patients. The expression of MHC class I and NLRC5 in NSCLC were detected using immunohistochemistry (IHC). The association between their expression levels was assessed using the Pearson's χ² test and their association with survival was assessed using Kaplan-Meier analysis and the log-rank test. In addition, the expression of NLRC5 and MHC class I were examined in 323 cases of seven other types of tumors and their correlations were studied. The results revealed that the expression of NLRC5 was correlated with that of MHC class I in NSCLC patients (P=0.008). MHC class I-positive and nuclear NLRC5-positive NSCLC patients were found to have shorter overall survival (OS) rates (log-rank, P=0.032 and P=0.039, respectively). In addition, in the seven different tumor types, there was a significant correlation between MHC class I and NLRC5 nuclear expression (P<0.001) as well as MHC class I and NLRC5 cytoplasmic expression (P=0.003). In conclusion, NLRC5 was demonstrated to be widely expressed in eight tumor tissues and its expression was correlated with that of MHC class I. Of note, nuclear NLRC5-negative and MHC class I-negative stage III NSCLC patients had improved OS rates compared to those with positive expression. Therefore, NLRC5 and MHC class I may be negative prognostic indicators in NSCLC stage III patients.

Cytotoxic reaction mediators: granzymes A and B in women with ovarian cancer

The purpose of this work was the assessment of cytotoxic reaction mediators - granzymes A and B in the serum of women with ovarian tumors. The study included 120 women with proven ovarian tumors. The control group consisted of 60 healthy women in whom no pathological changes within the reproductive system were detected. Concentrations of granzymes A and B were measured by enzyme-linked immunosorbent (ELISA) assay. The highest concentrations of the studied parameters were observed in serum of women with ovarian cancer. Moreover, the concentrations of granzymes A and B in patients with ovarian cancer were substantially increased in comparison to concentrations in patients with ovarian cystadenomas (P < 0.0001) or ovarian teratomas (P < 0.0001).

Anticancer immune reactivity and long-term survival after treatment of metastatic ovarian cancer with dendritic cells

Hematopoietic stem cells collected by leukapheresis of a patient with metastatic ovarian carcinoma (OVCA) were induced into dendritic cell (DC) differentiation and fused with liposomal constructs of autologous and allogeneic ovarian carcinoma antigens (DC-OVCA). The proliferation of autologous T cells induced by DCs was determined by [(3)H]-thymidine uptake. Maximal T-cell proliferation was observed in co-cultures of DCs fused with liposomal OVCA constructs compared with intact autologous OVCA cells. The combination of autologous and allogeneic liposomal OVCA constructs induced greater T-cell proliferation than either alone. The cytotoxicity of DC-activated T cells against various target cells were analyzed by a (51)Cr-release assay. The combination of autologous and allogeneic liposomal OVCA constructs showed the highest stimulation of T cell-mediated cytotoxicity against OVCA cells, but had minimal cytotoxicity against normal fibroblasts or leukemia cells. The liposomal preparations of DC-OVCA were injected monthly into a patient with metastatic ovarian carcinoma whose tumors progressed following multiple courses of chemotherapy. DCs analyzed from the patient post-immunization showed 2- to 3-fold greater OVCA cytotoxicity compared to pre-immunization DCs. Immunoblots using the patient's serum showed reactivity with a number of proteins from ovarian cancer extracts, but not in normal fibroblasts and breast cancer. Following the DC-OVCA treatment, the metastatic lesions progressively decreased in size to the point of being undetectable by serial CAT scans. Seven years following the initial diagnosis, the patient continues to be free of cancer. This report described the anticancer immune reactivity and anti-tumor response induced by DCs sensitized with liposomal constructs of OVCA antigens. Immune cell therapy may therefore be a useful adjunct to surgery and chemotherapy for the treatment of ovarian cancer.

Induction of cytotoxic T lymphocytes against ovarian cancer-initiating cells

The majority of patients with stage III/IV ovarian carcinoma that respond initially to standard therapies ultimately undergo relapse due to the survival of small populations of cells with tumor-initiating potential. These ovarian cancer (OVCA)-initiating cells (OCIC) are sometimes called cancer stem cells (CSC) because they express stem cell markers, and can survive conventional therapies such as chemotherapy, which usually target rapidly replicating tumor cells, and give rise to recurrent tumors that are more chemo-resistant and more aggressive. Thus, it would be desirable to develop a therapy that could selectively target OCIC and be used to complement the conventional therapies. In this study, we isolated a subset of OVCA cells with a CD44(+) phenotype in samples from patients with OVCA that possess CSC properties including the formation of spheroids in culture, self-renewal and the ability to be engrafted in immune-compromised mice. We next explored the use of immunotherapy using fusions of dendritic cells and OCIC to specifically target the OCIC subpopulations. Fusion cells (FCs) prepared in this way activated T cells to express elevated levels of IFN-γ with enhanced killing of CD44(+) OVCA cells. We envision a combined approach where conventional therapies such as chemotherapy kill the bulk of tumor cells, whereas OCIC-reactive cytotoxic T lymphocytes target the resistant OCIC fraction. A combined therapy such as this may represent a promising approach for the treatment of OVCA.

MHC class I-presented tumor antigens identified in ovarian cancer by immunoproteomic analysis are targets for T-cell responses against breast and ovarian cancer

PURPOSE

The purpose of this study is to test whether peptide epitopes chosen from among those naturally processed and overpresented within MHC molecules by malignant, but not normal cells, when formulated into cancer vaccines, could activate antitumor T-cell responses in humans.

EXPERIMENTAL DESIGN

Mixtures of human leukocyte antigen A2 (HLA-A2)-binding ovarian cancer-associated peptides were used to activate naive T cells to generate antigen-specific T cells that could recognize ovarian and breast cancers in vitro. Combinations of these peptides (0.3 mg of each peptide or 1 mg of each peptide) were formulated into vaccines in conjunction with Montanide ISA-51 and granulocyte monocyte colony stimulating factor which were used to vaccinate patients with ovarian and breast cancer without evidence of clinical disease in parallel pilot clinical trials.

RESULTS

T cells specific for individual peptides could be generated in vitro by using mixtures of peptides, and these T cells recognized ovarian and breast cancers but not nonmalignant cells. Patient vaccinations were well tolerated with the exception of local erythema and induration at the injection site. Nine of the 14 vaccinated patients responded immunologically to their vaccine by inducing peptide-specific T-cell responses that were capable of recognizing HLA-matched breast and ovarian cancer cells.

CONCLUSION

Mixtures of specific peptides identified as naturally presented on cancer cells and capable of activating tumor-specific T cells in vitro also initiate or augment immune responses toward solid tumors in cancer patients.

Priming and activation of human ovarian and breast cancer-specific CD8+ T cells by polyvalent Listeria monocytogenes-based vaccines

Immunotherapeutic vaccine is potentially an effective strategy to combat cancer. Essential components of an effective vaccine must include antigens that are processed by the major histocompatibility complex class I pathway, presented by the tumor major histocompatibility complex molecules, and an effective antigen delivery platform that is capable of breaking self-tolerance. In this study, we characterized a set of ovarian cancer-specific T-cell epitopes delivered by live-attenuated recombinant Listeria monocytogenes (Lm DeltaactADeltainlB) as a vaccine vector. We present data that peptide-specific T cells recognize the human monocytic cell line THP-1 infected with recombinant Lm DeltaactADeltainlB encoding the epitopes. Furthermore, we demonstrate that recombinant L. monocytogenes (Lm)-infected antigen-presenting cells can prime and expand epitope-specific CD8 T cells in vitro and such CD8 T cells recognize not only peptide-loaded targets but also ovarian and breast tumor cells presenting endogenous epitopes. Finally, peptide-specific T cells generated using peripheral blood mononuclear cell from ovarian cancer patients recognize target cells infected with recombinant Lm DeltaactADeltainlB encoding the epitopes. Our results demonstrate that live-attenuated recombinant Lm can be used effectively as a vehicle to deliver cancer peptide antigens singly or as a multiepitope construct. Thus, the use of recombinant live-attenuated Lm strains encoding endogenously processed and presented tumor epitopes/antigens represents an attractive strategy for active cancer immunotherapy in a clinical setting.

The impact of T-cell immunity on ovarian cancer outcomes

Ovarian cancer remains a challenging disease for which improved treatments are urgently needed. Most patients present with advanced disease that is highly responsive to surgery combined with platinum- and taxane-based chemotherapy, with a state of minimal residual disease being achieved in many cases. However, chemotherapy-resistant recurrent tumors typically appear within 1-5 years and are ultimately fatal. Recently, several groups have shown that ovarian tumors are often infiltrated by activated T cells at the time of diagnosis, and patients with dense infiltrates of CD3+CD8+ T cells experience unexpectedly favorable progression-free and overall survival. Other cell types in the immune infiltrate oppose anti-tumor immunity, including CD4+CD25+FoxP3+ regulatory T cells, CD8+ regulatory T cells, macrophages, and dendritic cells. The composition of immune infiltrates is shaped by the expression of cytokines, chemokines, antigens, major histocompatibility complex molecules, and costimulatory molecules. The relationship between these various immunological factors is reviewed here with a strong emphasis on outcomes data so as to create a knowledge base that is well grounded in clinical reality. With improved understanding of the functional properties of natural CD8+ T-cell responses to ovarian cancer, there is great potential to improve clinical outcomes by amplifying host immunity.

Tumor-infiltrating T cells correlate with NY-ESO-1-specific autoantibodies in ovarian cancer

Background

Tumor-infiltrating CD8+ T cells are correlated with prolonged progression-free and overall survival in epithelial ovarian cancer (EOC). A significant fraction of EOC patients mount autoantibody responses to various tumor antigens, however the relationship between autoantibodies and tumor-infiltrating T cells has not been investigated in EOC or any other human cancer. We hypothesized that autoantibody and T cell responses may be correlated in EOC and directed toward the same antigens.

Methodology and Principal Findings

We obtained matched serum and tumor tissue from 35 patients with high-grade serous ovarian cancer. Serum samples were assessed by ELISA for autoantibodies to the common tumor antigen NY-ESO-1. Tumor tissue was examined by immunohistochemistry for expression of NY-ESO-1, various T cell markers (CD3, CD4, CD8, CD25, FoxP3, TIA-1 and Granzyme B) and other immunological markers (CD20, MHC class I and MHC class II). Lymphocytic infiltrates varied widely among tumors and included cells positive for CD3, CD8, TIA-1, CD25, FoxP3 and CD4. Twenty-six percent (9/35) of patients demonstrated serum IgG autoantibodies to NY-ESO-1, which were positively correlated with expression of NY-ESO-1 antigen by tumor cells (r = 0.57, p = 0.0004). Autoantibodies to NY-ESO-1 were associated with increased tumor-infiltrating CD8+, CD4+ and FoxP3+ cells. In an individual HLA-A2+ patient with autoantibodies to NY-ESO-1, CD8+ T cells isolated from solid tumor and ascites were reactive to NY-ESO-1 by IFN-γ ELISPOT and MHC class I pentamer staining.

Conclusion and Significance

We demonstrate that tumor-specific autoantibodies and tumor-infiltrating T cells are correlated in human cancer and can be directed against the same target antigen. This implies that autoantibodies may collaborate with tumor-infiltrating T cells to influence clinical outcomes in EOC. Furthermore, serological screening methods may prove useful for identifying clinically relevant T cell antigens for immunotherapy.

Genetic alterations of HLA-class II in ovarian cancer

The immune system controls tumor formation through identification and elimination of cellular alterations. Consequently, cancer development in immune competent hosts depends on strategies to evade the immune system. Modulation of tumor antigen-specific immune responses by aberrant expression of HLA-class I and II molecules is well documented in a variety of carcinomas including ovarian cancer. To date, little data are available about molecular mechanisms responsible for altered HLA-class II phenotypes in tumors. In our sample of 10 Caucasian patients with ovarian carcinoma, a semiquantitative analysis was performed for HLA-class II loci DRB1 and DQB1 in malignant and normal ovarian tissue. Gene amplifications were identified in 62.5% of analyzed alleles and deletions in 17.5%, demonstrating that genomic aberrations of 6p21.3 are common and that copy number gain is more frequent than loss. Moreover, amplifications are most pronounced in advanced-stage tumors. To evaluate genotype-phenotype relation, immunohistochemical analyses were performed and revealed de novo expression of HLA-class II in 30% of tumors with an inverse association between antigen level and HLA copy number. It remains to be elucidated whether the profound changes of the latter quantities are the result of the host's immunological self-defense, indicate the presence of an oncogene located within the MHC-complex or merely reflect the increasing loss of differentiation of the tumor tissue.

Shared immunoproteome for ovarian cancer diagnostics and immunotherapy: potential theranostic approach to cancer

Elimination of cancer through early detection and treatment is the ultimate goal of cancer research and is especially critical for ovarian and other forms of cancer typically diagnosed at very late stages that have very poor response rates. Proteomics has opened new avenues for the discovery of diagnostic and therapeutic targets. Immunoproteomics, which defines the subset of proteins involved in the immune response, holds considerable promise for providing a better understanding of the early-stage immune response to cancer as well as important insights into antigens that may be suitable for immunotherapy. Early administration of immunotherapeutic vaccines can potentially have profound effects on prevention of metastasis and may potentially cure through efficient and complete tumor elimination. We developed a mass-spectrometry-based method to identify novel autoantibody-based serum biomarkers for the early diagnosis of ovarian cancer that uses native tumor-associated proteins immunoprecipitated by autoantibodies from sera obtained from cancer patients and from cancer-free controls to identify autoantibody signatures that occur at high frequency only in cancer patient sera. Interestingly, we identified a subset of more than 50 autoantigens that were also processed and presented by MHC class I molecules on the surfaces of ovarian cancer cells and thus were common to the two immunological processes of humoral and cell-mediated immunity. These shared autoantigens were highly representative of families of proteins with roles in key processes in carcinogenesis and metastasis, such as cell cycle regulation, cell proliferation, apoptosis, tumor suppression, and cell adhesion. Autoantibodies appearing at the early stages of cancer suggest that this detectable immune response to the developing tumor can be exploited as early-stage biomarkers for the development of ovarian cancer diagnostics. Correspondingly, because the T-cell immune response depends on MHC class I processing and presentation of peptides, proteins that go through this pathway are potential candidates for the development of immunotherapeutics designed to activate a T-cell immune response to cancer. To the best of our knowledge, this is the first comprehensive study that identifies and categorizes proteins that are involved in both humoral and cell-mediated immunity against ovarian cancer, and it may have broad implications for the discovery and selection of theranostic molecular targets for cancer therapeutics and diagnostics in general.

Preparation of human ovarian cancer ascites-derived exosomes for a clinical trial

Despite initial response to chemotherapy, at least 50% of ovarian cancer patients will relapse within 18 months. Progression-free survival is related to tumour infiltration with cytotoxic T lymphocytes (CTL). We recently demonstrated that CD8+ T cell responses to recall antigens improve following tumour response to chemotherapy. Vaccination designed to expand CTL, specific for tumour-associated antigens, may be a means of improving outcome. We are planning a clinical trial in advanced ovarian cancer patients undergoing chemotherapy using a combination of a Toll-like receptor 3 (TLR3) agonist and tumour-associated ascites-derived exosomes. Tumour-derived exosomes are a potential source of tumour antigens able to induce CD8+ T cell responses when loaded on mature dendritic cells (DC). DC maturation can be achieved with Toll-like receptor (TLR) agonists, such as the GMP-grade synthetic double stranded RNA, poly[I]:poly[C12U] (Ampligen) which is a TLR-3 agonist. Here, we describe the development of a method suitable for the preparation of GMP-grade exosomes from the ascites fluid of ovarian cancer patients, and the methods used for the molecular and immunological characterisation of these exosomes preceding their use in a clinical trial.

Immunologic aspect of ovarian cancer and p53 as tumor antigen

Ovarian cancer represents the fifth leading cause of death from all cancers for women. During the last decades overall survival has improved due to the use of new chemotherapy schedules. Still, the majority of patients die of this disease. Research reveals that ovarian cancer patients exhibit significant immune responses against their tumor. In this review the knowledge obtained thus far on the interaction of ovarian cancer tumor cells and the immune system is discussed. Furthermore the role of p53 as tumor antigen and its potential role as target antigen in ovarian cancer is summarized. Based on the increased knowledge on the role of the immune system in ovarian cancer major improvements are to be expected of immunotherapy based treatment of this disease.

Discrimination between serous low malignant potential and invasive epithelial ovarian tumors using molecular profiling

Tumors of low malignant potential (LMP) represent 20% of epithelial ovarian cancers (EOCs) and are associated with a better prognosis than the invasive tumors (TOV). Defining the relationship between LMPs and TOVs remains an important goal towards understanding the molecular pathways that contribute to prognosis, as well as providing molecular markers, for these EOCs. To this end, DNA microarray analyses were performed either in a primary culture or a tumor tissue model system and selected candidate genes showing a distinctive expression profile between LMPs and TOVs were identified using a class prediction approach based on three statistical methods of analysis. Both model systems appear relevant as candidate genes identified by either model allowed the proper reclassification of samples as either LMPs or TOVs. Selected candidate genes (CAS, CCNE1, LGALS8, ITGbeta3, ATP1B1, FLIP, KRT7 and KRT19) were validated by real-time quantitative PCR analysis and show differential expression between LMPs and TOVs. Immunohistochemistry analyses showed that the two tumor classes were distinguishable by their expression of CAS, TNFR1A, FLIP, CKS1 and CCNE1. These results define signature patterns for gene expression of LMPs and TOVs and identify gene candidates that warrant further study to deepen our understanding of the biology of EOC.

Detection of cancer cells in the axillary drainage using RT-PCR after operations for breast cancer

The object of this study was to examine whether MUC-1 can be detected in the axillary lymphatic drainage of patients who have undergone conservative surgery for breast cancer and to assess the correlations between the presence of MUC-1 and prognostic factors in breast cancer. Sixty-eight women with invasive ductal carcinoma of the breast underwent wide local excision and axillary lymph node dissection. Axillary drains were inserted in all these cases, and the presence of MUC-1 and beta-actin was evaluated by RT-PCR in the lymphatic fluid collected after the operation. Prognostic factors included tumour size and grade, vascular and lymphatic invasion, clearance margins of the resected specimens and status of the axillary lymph nodes. RT-PCR assays for MUC-1 in the axillary fluid were positive in 17 patients (25%). The presence of MUC-1 was associated with increased tumour size and showed a positive correlation with axillary lymph node metastases and incomplete resection of the tumour. RT-PCR can disclose cancer cells in the axillary fluid after conservative surgery for breast cancer. The presence of MUC-1 in the axillary drainage may be associated with poor prognostic features, and its detection may have implications for therapy as it suggests that re-excision should be considered.

HER-2/neu-mediated regulation of components of the MHC class I antigen-processing pathway

Because of its amplification and/or overexpression in many human tumors, the HER-2/neu proto-oncogene represents an attractive target for T-cell-mediated vaccination strategies. However, overexpression of oncogenes is often associated with defective expression of components of the MHC class I antigen-processing machinery (APM), thereby resulting in an immune escape phenotype of oncogene-transformed cells. To determine whether HER-2/neu influences the MHC class I antigen-processing pathway, the expression pattern of different APM components was examined in murine in vitro models of constitutive and tetracycline-controlled HER-2/neu expression. In comparison with HER-2/neu(-) control cells, HER-2/neu(+) fibroblasts exhibit reduced levels of MHC class I surface antigens that were associated with impaired expression and/or function of the peptide transporter associated with antigen processing, the proteasome subunits low molecular weight protein 2 and low molecular weight protein 10, the proteasome activators PA28alpha and PA28beta, and tapasin. These APM abnormalities resulted in reduced sensitivity to lysis by CTLs. The HER-2/neu-mediated immune escape phenotype could be corrected by IFN-gamma treatment. The clinical relevance of this finding was supported by an inverse correlation between HER-2/neu and the peptide transporter associated with antigen-processing protein expression as determined by immunhistochemical analysis of a series of HER-2/neu(-) and HER-2/neu(+) breast cancer specimens. Thus, a functional link between deficient APM component expression and HER-2/neu overexpression is proposed that might influence the design of HER-2/neu-targeted T-cell-based immunotherapeutic strategies.