Cellular immunotherapy for ovarian cancer

A novel method for efficient generation of antigen-specific effector T-cells using dendritic cells transduced with recombinant adeno-associated virus and p38 kinase blockade

Background

The inefficacy of standard therapeutic strategies for ovarian cancer is reflected by the enduring poor prognosis of this malignancy. Due to the potential for exquisite specificity, sensitivity and long-term memory, immunotherapy offers an alternative modality for durable control of the disease, provided appropriate antigens can be identified and presented in the right context.

Methods

We tested a novel dendritic cell vaccine formulation to reprogram autologous antigen-specific T-cells in vitro, in vivo in a murine model of ovarian cancer, and ex vivo using human cells from patients.

Results

We show that dendritic cells (DCs) treated with a p38 MAPK inhibitor and transduced with a recombinant adenovirus associated vector (AAV) expressing Sperm protein (Sp) 17 are highly effective in generating antigen-specific T-cell cytotoxic response against ovarian cancer cells. Additionally, these DCs enhanced the differentiation of effector T-cells while reducing the frequency of Foxp3⁺ T-reg cells in vitro.

Conclusions

This work provides a rationale for translation of pharmacologically reprogrammed DCs into clinical trials for prevention of tumor recurrence and progression in high-risk ovarian cancer patients.

[Immunological aspects of ovarian cancer: Therapeutic perspectives]

Ovarian cancer is recognized by the immunological system of its host. Initially, it is effective to destroy and eliminate the cancer. But gradually, resistant tumor cells more aggressive and those able to protect themselves by inducing immune tolerance will be selected. Immunotherapy to be effective should consider both components of immune response with an action on cytotoxic immune effectors and action on tolerance mechanisms. The manipulations of the immune system should be cautious, because the immune effects are not isolated. A theoretically efficient handling may simultaneously cause an adverse effect which was not envisaged and could neutralize the benefits of treatment. Knowledge of tolerance mechanisms set up by the tumor is for the clinician a prerequisite before they prescribe these treatments. For each cancer, the knowledge of its immunological status is a prerequisite to propose adapted immunological therapies.

Tumor infiltrating lymphocytes in ovarian cancer

The accumulation of tumor infiltrating lymphocytes (TILs) in ovarian cancer is prognostic for increased survival while increases in immunosuppressive regulatory T-cells (Tregs) are associated with poor outcomes. Approaches that bolster tumor-reactive TILs may limit tumor progression. However, identifying tumor-reactive TILs in ovarian cancer has been challenging, though adoptive TIL therapy in patients has been encouraging. Other forms of TIL immunomodulation remain under investigation including Treg depletion, antibody-based checkpoint modification, activation and amplification using dendritic cells, antigen presenting cells or IL-2 cytokine culture, adjuvant cytokine injections, and gene-engineered T-cells. Many approaches to TIL manipulation inhibit ovarian cancer progression in preclinical or clinical studies as monotherapy. Here, we review the impact of TILs in ovarian cancer and attempts to mobilize TILs to halt tumor progression. We conclude that effective TIL therapy for ovarian cancer is at the brink of translation and optimal TIL activity may require combined methodologies to deliver clinically-relevant treatment.

Tumor infiltrating lymphocytes in ovarian cancer

The accumulation of tumor infiltrating lymphocytes (TILs) in ovarian cancer is prognostic for increased survival while increases in immunosuppressive regulatory T-cells (Tregs) are associated with poor outcomes. Approaches that bolster tumor-reactive TILs may limit tumor progression. However, identifying tumor-reactive TILs in ovarian cancer has been challenging, though adoptive TIL therapy in patients has been encouraging. Other forms of TIL immunomodulation remain under investigation including Treg depletion, antibody-based checkpoint modification, activation and amplification using dendritic cells, antigen presenting cells or IL-2 cytokine culture, adjuvant cytokine injections, and gene-engineered T-cells. Many approaches to TIL manipulation inhibit ovarian cancer progression in preclinical or clinical studies as monotherapy. Here, we review the impact of TILs in ovarian cancer and attempts to mobilize TILs to halt tumor progression. We conclude that effective TIL therapy for ovarian cancer is at the brink of translation and optimal TIL activity may require combined methodologies to deliver clinically-relevant treatment.

Tumor infiltrating lymphocytes in ovarian cancer

The accumulation of tumor infiltrating lymphocytes (TILs) in ovarian cancer is prognostic for increased survival while increases in immunosuppressive regulatory T-cells (Tregs) are associated with poor outcomes. Approaches that bolster tumor-reactive TILs may limit tumor progression. However, identifying tumor-reactive TILs in ovarian cancer has been challenging, though adoptive TIL therapy in patients has been encouraging. Other forms of TIL immunomodulation remain under investigation including Treg depletion, antibody-based checkpoint modification, activation and amplification using dendritic cells, antigen presenting cells or IL-2 cytokine culture, adjuvant cytokine injections, and gene-engineered T-cells. Many approaches to TIL manipulation inhibit ovarian cancer progression in preclinical or clinical studies as monotherapy. Here, we review the impact of TILs in ovarian cancer and attempts to mobilize TILs to halt tumor progression. We conclude that effective TIL therapy for ovarian cancer is at the brink of translation and optimal TIL activity may require combined methodologies to deliver clinically-relevant treatment.

A review of dendritic cell therapy for cancer: progress and challenges

Dendritic cells are the professional antigen-presenting cells of the innate immune system with the potential to generate robust antigen-specific T cell immune responses. Immunotherapeutic strategies have attempted to monopolize on this ability of dendritic cells to deliver antigens as a means of therapeutic vaccination in individuals with advanced malignancies. Since the publication of the first clinical trial in melanoma patients in 1995, therapeutic dendritic cell cancer vaccines have been extensively studied in numerous phase I and II trials. While advances have been encountered (especially with prostate cancer), there are still considerable challenges that need to be addressed in future clinical trials. In this review, we describe the current methodology and highlight trials which have contributed to the development of dendritic cell vaccines. We then review strategies to optimize dendritic cell vaccines in order to improve antitumor responses in cancer patients.

Tumor antigen-/cytokine-pulsed dendritic cells in therapy against lymphoma

Adoptive cell therapy using dendritic cells (DCs) is a strategy to deliver tumor antigens in cancer immunotherapy. Co-delivery of antigens to DC with essential components like genes encoding cytokines, chemokines, and other molecules or stimulation with recombinant cytokines is a potential method for designing an effective tumor vaccine protocol. Here, we describe the stimulation of purified splenic- or bone marrow-derived DC with recombinant interleukin-15 (IL-15) in the presence of intact soluble antigen from metastatic lymphoma tumor cells in an experimental animal model.

Dendritic cell immunotherapy in ovarian cancer

Ovarian cancer is one of the most frequent gynecological malignancies. However, as there is no effective screening method to detect early disease, it is usually only diagnosed when already widespread in the abdomen. The majority of patients diagnosed with advanced-stage disease will relapse and require additional therapy. In the search for additional effective treatments for the management of recurrent disease, researchers have focused on the potential usefulness of immunotherapeutic modulation by administering autologous immune cells, such as dendritic cells (DCs), to stimulate antitumor host responses. With the ultimate goal of improved survival, this review addresses mechanisms in ovarian cancer that may limit the expansion of antitumor immunity, discusses the parameters to be considered for optimal DC immunotherapy, outlines evaluation methodology used to monitor the success of treatment regimens and reviews reported DC immunotherapy trials in ovarian cancer.

Multifaceted therapeutic targeting of ovarian peritoneal carcinomatosis through virus-induced immunomodulation

Immunosuppression associated with ovarian cancer (OC) and resultant peritoneal carcinomatosis (PC) hampers the efficacy of many promising treatment options, including immunotherapies. It is hypothesized that oncolytic virus-based therapies can simultaneously kill OC and mitigate immunosuppression. Currently, reovirus-based anticancer therapy is undergoing phase I/II clinical trials for the treatment of OC. Hence, this study was focused on characterizing the effects of reovirus therapy on OC and associated immune microenvironment. Our data shows that reovirus efficiently killed OC cells and induced higher expression of the molecules involved in antigen presentation including major histocompatibility complex (MHC) class I, β2-microglobulin (β2M), TAP-1, and TAP-2. In addition, in the presence of reovirus, dendritic cells (DCs) overcame the OC-mediated phenotypic suppression and successfully stimulated tumor-specific CD8+ T cells. In animal studies, reovirus targeted local and distal OC, alleviated the severity of PC and significantly prolonged survival. These therapeutic effects were accompanied by decreased frequency of suppressive cells, e.g., Gr1.1+, CD11b+ myeloid derived suppressor cells (MDSCs), and CD4+, CD25+, FOXP3+ Tregs, tumor-infiltration of CD3+ cells and higher expression of Th1 cytokines. Finally, reovirus therapy during early stages of OC also resulted in the postponement of PC development. This report elucidates timely information on a therapeutic approach that can target OC through clinically desired multifaceted mechanisms to better the outcomes.

Immunotherapy of cancer in 2012

The immunotherapy of cancer has made significant strides in the past few years due to improved understanding of the underlying principles of tumor biology and immunology. These principles have been critical in the development of immunotherapy in the laboratory and in the implementation of immunotherapy in the clinic. This improved understanding of immunotherapy, enhanced by increased insights into the mechanism of tumor immune response and its evasion by tumors, now permits manipulation of this interaction and elucidates the therapeutic role of immunity in cancer. Also important, this improved understanding of immunotherapy and the mechanisms underlying immunity in cancer has fueled an expanding array of new therapeutic agents for a variety of cancers. Pegylated interferon-α2b as an adjuvant therapy and ipilimumab as therapy for advanced disease, both of which were approved by the United States Food and Drug Administration for melanoma in March 2011, are 2 prime examples of how an increased understanding of the principles of tumor biology and immunology have been translated successfully from the laboratory to the clinical setting. Principles that guide the development and application of immunotherapy include antibodies, cytokines, vaccines, and cellular therapies. The identification and further elucidation of the role of immunotherapy in different tumor types, and the development of strategies for combining immunotherapy with cytotoxic and molecularly targeted agents for future multimodal therapy for cancer will enable even greater progress and ultimately lead to improved outcomes for patients receiving cancer immunotherapy.

Immunotherapy in ovarian cancer

Ovarian cancer is the most deadly gynecologic malignancy, with more than 15,000 deaths anticipated in 2012. While approximately 80% of patients will respond to frontline chemotherapy, more than 60% of patients will experience disease recurrence and only 44% will be alive at 5 y. Host anti-tumor immune responses are associated with a significant improvement in overall survival for women with ovarian cancer. By bolstering these responses, it may therefore be possible to significantly influence the prognosis of women with this lethal disease. In this review, we will focus on innovative immune-based strategies which are currently being investigated in the treatment of ovarian cancer.

Vaccine-based clinical trials in ovarian cancer

Ovarian cancer vaccines are one of the new treatment strategies under investigation in epithelial ovarian cancer. This article discusses the results of different immunization strategies, points out potential pitfalls in study designs and provides possible solutions for augmentation of clinical efficacy. Most ovarian cancer vaccines have not yet evolved beyond Phase I/II studies, which do not primarily evaluate clinical efficacy. Although different approaches of antigen-specific immunization generally result in antigen-specific immune responses, clinical benefit is not consistently observed. Based on the currently available results, we emphasize the necessity of multimodal treatment of ovarian cancer, combining classical cytoreductive surgery, (neo)adjuvant chemotherapy, immunotherapy and/or targeted therapy.

Antigen-presenting cell (APC) subsets in ovarian cancer

The major human antigen-presenting cells (APCs) include monocytes/macrophages, myeloid dendritic cells (mDC), plasmacytoid dendritic cells (pDC), and B cells. These APC subsets have been observed in ovarian tumor environments. Their phenotypes and functionalities are subjected to alteration by multiple factors in the tumor environment. In this review, we summarize the nature, cellular interactions, and prognostic significance of the main APC populations in ovarian cancer, and discuss the relevance of manipulating APC subsets for patient treatment.

Establishment, characterization, and successful adaptive therapy against human tumors of NKG cell, a new human NK cell line

Natural killer (NK) cells play important roles in adoptive cellular immunotherapy against certain human cancers. This study aims to establish a new human NK cell line and to study its role for adoptive cancer immunotherapy. Peripheral blood samples were collected from 54 patients to establish the NK cell line. A new human NK cell line, termed as NKG, was established from a Chinese male patient with rapidly progressive non-Hodgkin's lymphoma. NKG cells showed LGL morphology and were phenotypically identified as CD56(bright) NK cell with CD16(-), CD27(-), CD3(-), αβTCR(-), γδTCR(-), CD4(-), CD8(-), CD19(-), CD161(-), CD45(+), CXCR4(+), CCR7(+), CXCR1(-), and CX3CR1(-). NKG cells showed high expression of adhesive molecules (CD2, CD58, CD11a, CD54, CD11b, CD11c), an array of activating receptors (NKp30, NKp44, NKp46, NKG2D, NKG2C), and cytolysis-related receptors and molecules (TRAIL, FasL, granzyme B, perforin, IFN-γ). The cytotoxicity of NKG cells against tumor cells was higher than that of the established NK cell lines NK-92, NKL, and YT. NKG cell cytotoxicity depended on the presence of NKG2D and NKp30. When irradiated with 8 Gy, NKG cells were still with high cytotoxicity and activity in vitro and with safety in vivo, but without proliferation. Further, the irradiated NKG cells exhibited strong cytotoxicity against human primary ovarian cancer cells in vitro, and against human ovarian cancer in a mouse xenograft model. The adoptive transfer of NKG cells significantly inhibited the ovarian tumor growth, decreased the mortality rate and prolonged the survival, even in cases of advanced diseases. A number of NKG cells were detected in the ovarian tumor tissues during cell therapy. In use of the new human NK cell line, NKG would a promising cellular candidate for adoptive immunotherapy of human cancer.

Targeted treatment of recurrent platinum-resistant ovarian cancer: current and emerging therapies

With advances in surgical techniques and chemotherapeutic agents, mortality rates from epithelial ovarian cancer (EOC) have slightly decreased over the last 30 years. However, EOC still ranks as the most deadly gynecologic cancer with an overall 5-year survival rate of 45%. Prognosis is especially disappointing for women with platinum-resistant disease, where 80% of patients will fail to respond to available therapies. Emerging treatment strategies have sub-sequently focused on targets which are integral to tumor growth and metastasis. In this review, we will focus on those innovative agents currently under investigation in clinical trials.

Immunotherapy for ovarian cancer: what's next?

In the past decade, we have witnessed important gains in the treatment of ovarian cancer; however, additional advances are required to reduce mortality. With compelling evidence that ovarian cancers are immunogenic tumors, immunotherapy should be further pursued and optimized. The dramatic advances in laboratory and clinical procedures in cellular immunotherapy, along with the development of powerful immunomodulatory antibodies, create new opportunities in ovarian cancer therapeutics. Herein, we review current progress and future prospects in vaccine and adoptive T-cell therapy development as well as immunomodulatory therapy tools available for immediate clinical testing.

Cancer testis antigen vaccination affords long-term protection in a murine model of ovarian cancer

Sperm protein (Sp17) is an attractive target for ovarian cancer (OC) vaccines because of its over-expression in primary as well as in metastatic lesions, at all stages of the disease. Our studies suggest that a Sp17-based vaccine can induce an enduring defense against OC development in C57BL/6 mice with ID8 cells, following prophylactic and therapeutic treatments. This is the first time that a mouse counterpart of a cancer testis antigen (Sp17) was shown to be expressed in an OC mouse model, and that vaccination against this antigen significantly controlled tumor growth. Our study shows that the CpG-adjuvated Sp17 vaccine overcomes the issue of immunologic tolerance, the major barrier to the development of effective immunotherapy for OC. Furthermore, this study provides a better understanding of OC biology by showing that Th-17 cells activation and contemporary immunosuppressive T-reg cells inhibition is required for vaccine efficacy. Taken together, these results indicate that prophylactic and therapeutic vaccinations can induce long-standing protection against OC and delay tumor growth, suggesting that this strategy may provide additional treatments of human OC and the prevention of disease onset in women with a family history of OC.

Whole tumor antigen vaccines

Although cancer vaccines with defined antigens are commonly used, the use of whole tumor cell preparations in tumor immunotherapy is a very promising approach and can obviate some important limitations in vaccine development. Whole tumor cells are a good source of TAAs and can induce simultaneous CTLs and CD4(+) T helper cell activation. We review current approaches to prepare whole tumor cell vaccines, including traditional methods of freeze-thaw lysates, tumor cells treated with ultraviolet irradiation, and RNA electroporation, along with more recent methods to increase tumor cell immunogenicity with HOCl oxidation or infection with replication-incompetent herpes simplex virus.

Blocking ovarian cancer progression by targeting tumor microenvironmental leukocytes

Current therapies for metastatic ovarian carcinoma are based on surgical debulking followed by chemotherapy. After more than three decades implementing treatments that selectively target the tumor cell, the 5-year survival rate for metastatic ovarian cancer patients is still lower than 30%. Novel strategies are therefore urgently needed to complement classical treatments for this malignancy. Recently, leukocytes in the ovarian cancer microenvironment such as regulatory T cells and immature pro-angiogenic/tolerogenic myeloid cells have been demonstrated to play a fundamental role in tumor progression. This review focuses on our recent understanding of the potential of eliminating and/or modulating the phenotype of these leukocytes in vivo and in situ as a novel intervention to complement standard ovarian cancer treatments. The significant effects of targeting these crucial microenvironmental players on cancer vascularization, local tumor growth, distal metastatic spreading and spontaneous anti-tumor immune responses are discussed.