The emergence of immunomodulation: combinatorial immunochemotherapy opportunities for the next decade

Bioengineering strategies to enhance the interleukin-18 bioactivity in the modern toolbox of cancer immunotherapy

Cytokines are the first modern immunotherapeutic agents used for activation immunotherapy. Interleukin-18 (IL-18) has emerged as a potent anticancer immunostimulatory cytokine over the past three decades. IL-18, structurally is a stable protein with very low toxicity at biological doses. IL-18 promotes the process of antigen presentation and also enhances innate and acquired immune responses. It can induce the production of proinflammatory cytokines and increase tumor infiltration of effector immune cells to revert the immunosuppressive milieu of tumors. Furthermore, IL-18 can reduce tumorigenesis, suppress tumor angiogenesis, and induce tumor cell apoptosis. These characteristics present IL-18 as a promising option for cancer immunotherapy. Although several preclinical studies have reported the immunotherapeutic potential of IL-18, clinical trials using it as a monotherapy agent have reported disappointing results. These results may be due to some biological characteristics of IL-18. Several bioengineering approaches have been successfully used to correct its defects as a bioadjuvant. Currently, the challenge with this anticancer immunotherapeutic agent is mainly how to use its capabilities in a rational combinatorial therapy for clinical applications. The present study discussed the strengths and weaknesses of IL-18 as an immunotherapeutic agent, followed by comprehensive review of various promising bioengineering approaches that have been used to overcome its disadvantages. Finally, this study highlights the promising application of IL-18 in modern combinatorial therapies, such as chemotherapy, immune checkpoint blockade therapy, cell-based immunotherapy and cancer vaccines to guide future studies, circumventing the barriers to administration of IL-18 for clinical applications, and bring it to fruition as a potent immunotherapy agent in cancer treatment.

ROS Cocktails as an Adjuvant for Personalized Antitumor Vaccination?

Cancer is the second leading cause of death worldwide. Today, the critical role of the immune system in tumor control is undisputed. Checkpoint antibody immunotherapy augments existing antitumor T cell activity with durable clinical responses in many tumor entities. Despite the presence of tumor-associated antigens and neoantigens, many patients have an insufficient repertoires of antitumor T cells. Autologous tumor vaccinations aim at alleviating this defect, but clinical success is modest. Loading tumor material into autologous dendritic cells followed by their laboratory expansion and therapeutic vaccination is promising, both conceptually and clinically. However, this process is laborious, time-consuming, costly, and hence less likely to solve the global cancer crisis. Therefore, it is proposed to re-focus on personalized anticancer vaccinations to enhance the immunogenicity of autologous therapeutic tumor vaccines. Recent work re-established the idea of using the alarming agents of the immune system, oxidative modifications, as an intrinsic adjuvant to broaden the antitumor T cell receptor repertoire in cancer patients. The key novelty is the use of gas plasma, a multi-reactive oxygen and nitrogen species-generating technology, for diversifying oxidative protein modifications in a, so far, unparalleled manner. This significant innovation has been successfully used in proof-of-concept studies and awaits broader recognition and implementation to explore its chances and limitations of providing affordable personalized anticancer vaccines in the future. Such multidisciplinary advance is timely, as the current COVID-19 crisis is inexorably reflecting the utmost importance of innovative and effective vaccinations in modern times.

Immunostimulatory biomaterials to boost tumor immunogenicity

Cancer immunotherapy is exhibiting great promise as a new therapeutic modality for cancer treatment. However, immunotherapies are limited by the inability of some tumors to provoke an immune response. These tumors with a 'cold' immunological phenotype are characterized by low numbers of tumor-infiltrating lymphocytes, high numbers of immunosuppressive leukocytes (e.g. regulatory T cells, tumor-associated macrophages), and high production of immune-dampening signals (e.g. IL-10, TGF-β, IDO-1). Strategies to boost the aptitude of tumors to initiate an immune response (i.e. boost tumor immunogenicity) will turn 'cold' tumors 'hot' and augment the anti-tumor efficacy of current immunotherapies. Approaches to boost tumor immunogenicity already show promise; however, multifaceted delivery and immunobiology challenges exist. For instance, systemic delivery of many immune-stimulating agents causes off-target toxicity and/or the development of autoimmunity, limiting the administrable dose below the threshold needed to achieve efficacy. Moreover, once administered in vivo, molecules such as the nucleic acid-based agonists for many pattern recognition receptors are either rapidly cleared or degraded, and don't efficiently traffic to the intracellular compartments where the receptors are located. Thus, these nucleic acid-based drugs are ineffective without a delivery system. Biomaterials-based approaches aim to enhance current strategies to boost tumor immunogenicity, enable novel strategies, and spare dose-limiting toxicities. Here, we review recent progress to improve cancer immunotherapies by boosting immunogenicity within tumors using immunostimulatory biomaterials.

Endometrial cancer evolution: new molecular-biologic types and hormonal-metabolic shifts

The question hidden in the title of this manuscript (whether the topic develops or remains constant) is important for all areas of science. It is also a serious problem for endometrial cancer (EC) study. In recent times the incidence of EC gradually increases in parallel with obesity epidemics. The main point of this review was evaluation of changes in EC area in last few decades, which are not only seen in tumor incidence, but also in its biology, hormonal-metabolic characteristics of patients and in the ratio of risk and anti-risk factors. One can hope that data accumulated recently and summarized here under the notion of EC evolution will find its use for advancement of EC prevention and treatment.

The era of bioengineering: how will this affect the next generation of cancer immunotherapy?

Background

Immunotherapy consists of activating the patient’s immune system to fight cancer and has the great potential of preventing future relapses thanks to immunological memory. A great variety of strategies have emerged to harness the immune system against tumors, from the administration of immunomodulatory agents that activate immune cells, to therapeutic vaccines or infusion of previously activated cancer-specific T cells. However, despite great recent progress many difficulties still remain, which prevent the widespread use of immunotherapy. Some of these limitations include: systemic toxicity, weak immune cellular responses or persistence over time and most ultimately costly and time-consuming procedures.

Main body

Synthetic and natural biomaterials hold great potential to address these hurdles providing biocompatible systems capable of targeted local delivery, co-delivery, and controlled and/or sustained release. In this review we discuss some of the bioengineered solutions and approaches developed so far and how biomaterials can be further implemented to help and shape the future of cancer immunotherapy.

Conclusion

The bioengineering strategies here presented constitute a powerful toolkit to develop safe and successful novel cancer immunotherapies.

Safety and immunogenicity of neoadjuvant treatment using WT1-immunotherapeutic in combination with standard therapy in patients with WT1-positive Stage II/III breast cancer: a randomized Phase I study

Purpose

This Phase I, multicenter, randomized study (ClinicalTrials.gov NCT01220128) evaluated the safety and immunogenicity of recombinant Wilms’ tumor 1 (WT1) protein combined with the immunostimulant AS15 (WT1-immunotherapeutic) as neoadjuvant therapy administered concurrently with standard treatments in WT1-positive breast cancer patients.

Methods

Patients were treated in 4 cohorts according to neoadjuvant treatment (A: post-menopausal, hormone receptor [HR]-positive patients receiving aromatase inhibitors; B: patients receiving chemotherapy; C: HER2-overexpressing patients on trastuzumab–chemotherapy combination; D: HR-positive/HER2-negative patients on chemotherapy). Patients (cohorts A–C) were randomized (2:1) to receive 6 or 8 doses of WT1-immunotherapeutic or placebo together with standard neoadjuvant treatment in a double-blind manner; cohort D patients received WT1-immunotherapeutic in an open manner. Safety was assessed throughout the study. WT1-specific antibodies were assessed pre- and post-vaccination.

Results

Sixty-two patients were randomized; 60 received ≥ one dose of WT1-immunotherapeutic. Two severe toxicities were reported: diarrhea (cohort C; also reported as a grade 3 serious adverse event) and decreased left ventricular ejection fraction (cohort B; also reported as a grade 2 adverse event). Post-dose 4 of WT1-immunotherapeutic, 10/10 patients from cohort A, 0/8 patients from cohort B, 6/11 patients from cohort C, and 2/3 patients from cohort D were humoral responders. The sponsor elected to close the trial prematurely.

Conclusions

Concurrent administration of WT1-immunotherapeutic and standard neoadjuvant therapy was well tolerated and induced WT1-specific antibodies in patients receiving neoadjuvant aromatase inhibitors. In patients on neoadjuvant chemotherapy or trastuzumab–chemotherapy combination, the humoral response was impaired or blunted, likely due to either co-administration of corticosteroids and/or the chemotherapies themselves.

Electronic supplementary material

The online version of this article (doi:10.1007/s10549-017-4130-y) contains supplementary material, which is available to authorized users.

Imiquimod Induces Apoptosis in Human Endometrial Cancer Cells In vitro and Prevents Tumor Progression In vivo

PURPOSE

The increasing incidence of endometrial cancer (EC), in younger age at diagnosis, calls for new tissue-sparing treatment options. This work aims to evaluate the potential of imiquimod (IQ) in the treatment of low-grade EC.

METHODS

Effects of IQ on the viabilities of Ishikawa and HEC-1A cells were evaluated using MTT assay. The ability of IQ to induce apoptosis was evaluated by testing changes in caspase 3/7 levels and expression of cleaved caspase-3, using luminescence assay and western blot. Apoptosis was confirmed by flow cytometry and the expression of cleaved PARP. Western blot was used to evaluate the effect of IQ on expression levels of Bcl-2, Bcl-xL, and BAX. Finally, the in vivo efficacy of IQ was tested in an EC mouse model.

RESULTS

There was a decrease in EC cell viability following IQ treatment as well as increased caspase 3/7 activities, cleaved caspase-3 expression, and Annexin-V/ 7AAD positive cell population. Western blot results showed the ability of IQ in cleaving PARP, decreasing Bcl-2 and Bcl-xL expressions, but not affecting BAX expression. In vivo study demonstrated IQ's ability to inhibit EC tumor growth and progression without significant toxicity.

CONCLUSIONS

IQ induces apoptosis in low-grade EC cells in vitro, probably through its direct effect on Bcl-2 family protein expression. In, vivo, IQ attenuates EC tumor growth and progression, without an obvious toxicity. Our study provides the first building block for the potential role of IQ in the non-surgical management of low-grades EC and encouraging further investigations.

Association of Immunosuppression with DR6 Expression during the Development and Progression of Spontaneous Ovarian Cancer in Laying Hen Model

Ovarian cancer (OVCA) mainly disseminates in the peritoneal cavity. Immune functions are important to prevent OVCA progression and recurrence. The mechanism of immunosuppression, a hallmark of tumor progression, is not well understood. The goal of this study was to determine the immune system's responses and its suppression during OVCA development and progression in hens. Frequencies of CD8+ T cells and IgY-containing cells and expression of immunosuppressors including IRG1 and DR6 in OVCA at early and late stages in hens were examined. Frequencies of stromal but not the intratumoral CD+8 T cells and IgY-containing cells increased significantly (P < 0.01) during OVCA development and progression. Tumor progression was associated with increased expression of IRG1 and DR6 and decreased infiltration of immune cells into the tumor. Frequency of stromal but not intratumoral immune cells increases during OVCA development and progression. Tumor-induced IRG1 and DR6 may prevent immune cells from invading the tumor.

IFN-γ from lymphocytes induces PD-L1 expression and promotes progression of ovarian cancer

BACKGROUND

PD-L1 (programmed cell death 1 ligand 1) on tumour cells suppresses host immunity through binding to its receptor PD-1 on lymphocytes, and promotes peritoneal dissemination in mouse models of ovarian cancer. However, how PD-L1 expression is regulated in ovarian cancer microenvironment remains unclear.

METHODS

The number of CD8-positive lymphocytes and PD-L1 expression in tumour cells was assessed in ovarian cancer clinical samples. PD-L1 expression and tumour progression in mouse models under conditions of altering IFN-γ signals was assessed.

RESULTS

The number of CD8-positive cells in cancer stroma was very high in peritoneally disseminated tumours, and was strongly correlated to PD-L1 expression on the tumour cells (P<0.001). In mouse models, depleting IFNGR1 (interferon-γ receptor 1) resulted in lower level of PD-L1 expression in tumour cells, increased the number of tumour-infiltrating CD8-positive lymphocytes, inhibition of peritoneal disseminated tumour growth and longer survival (P=0.02). The injection of IFN-γ into subcutaneous tumours induced PD-L1 expression and promoted tumour growth, and PD-L1 depletion completely abrogated tumour growth caused by IFN-γ injection (P=0.01).

CONCLUSIONS

Interferon-γ secreted by CD8-positive lymphocytes upregulates PD-L1 on ovarian cancer cells and promotes tumour growth. The lymphocyte infiltration and the IFN-γ status may be the key to effective anti-PD-1 or anti-PD-L1 therapy in ovarian cancer.

IFN-γ from lymphocytes induces PD-L1 expression and promotes progression of ovarian cancer

BACKGROUND

PD-L1 (programmed cell death 1 ligand 1) on tumour cells suppresses host immunity through binding to its receptor PD-1 on lymphocytes, and promotes peritoneal dissemination in mouse models of ovarian cancer. However, how PD-L1 expression is regulated in ovarian cancer microenvironment remains unclear.

METHODS

The number of CD8-positive lymphocytes and PD-L1 expression in tumour cells was assessed in ovarian cancer clinical samples. PD-L1 expression and tumour progression in mouse models under conditions of altering IFN-γ signals was assessed.

RESULTS

The number of CD8-positive cells in cancer stroma was very high in peritoneally disseminated tumours, and was strongly correlated to PD-L1 expression on the tumour cells (P<0.001). In mouse models, depleting IFNGR1 (interferon-γ receptor 1) resulted in lower level of PD-L1 expression in tumour cells, increased the number of tumour-infiltrating CD8-positive lymphocytes, inhibition of peritoneal disseminated tumour growth and longer survival (P=0.02). The injection of IFN-γ into subcutaneous tumours induced PD-L1 expression and promoted tumour growth, and PD-L1 depletion completely abrogated tumour growth caused by IFN-γ injection (P=0.01).

CONCLUSIONS

Interferon-γ secreted by CD8-positive lymphocytes upregulates PD-L1 on ovarian cancer cells and promotes tumour growth. The lymphocyte infiltration and the IFN-γ status may be the key to effective anti-PD-1 or anti-PD-L1 therapy in ovarian cancer.

Metronomic cyclophosphamide eradicates large implanted GL261 gliomas by activating antitumor Cd8+ T-cell responses and immune memory

Cancer chemotherapy using cytotoxic drugs can induce immunogenic tumor cell death; however, dosing regimens and schedules that enable single-agent chemotherapy to induce adaptive immune-dependent ablation of large, established tumors with activation of long-term immune memory have not been identified. Here, we investigate this issue in a syngeneic, implanted GL261 glioma model in immune-competent mice given cyclophosphamide on a 6-day repeating metronomic schedule. Two cycles of metronomic cyclophosphamide treatment induced sustained upregulation of tumor-associated CD8⁺ cytotoxic T lymphocyte (CTL) cells, natural killer (NK) cells, macrophages, and other immune cells. Expression of CTL- and NK–cell-shared effectors peaked on Day 6, and then declined by Day 9 after the second cyclophosphamide injection and correlated inversely with the expression of the regulatory T cell (Treg) marker Foxp3. Sustained tumor regression leading to tumor ablation was achieved after several cyclophosphamide treatment cycles. Tumor ablation required CD8⁺ T cells, as shown by immunodepletion studies, and was associated with immunity to re-challenge with GL261 glioma cells, but not B16-F10 melanoma or Lewis lung carcinoma cells. Rejection of GL261 tumor re-challenge was associated with elevated CTLs in blood and increased CTL infiltration in tumors, consistent with the induction of long-term, specific CD8⁺ T-cell anti-GL261 tumor memory. Co-depletion of CD8⁺ T cells and NK cells did not inhibit tumor regression beyond CD8⁺ T-cell depletion alone, suggesting that the metronomic cyclophosphamide-activated NK cells function via CD8a⁺ T cells. Taken together, these findings provide proof-of-concept that single-agent chemotherapy delivered on an optimized metronomic schedule can eradicate large, established tumors and induce long-term immune memory.

Tumor-infiltrating memory T-lymphocytes for prognostic prediction in cancer patients: a meta-analysis

PURPOSE

Pathological evidence has continually supported the prognostic value of tumour-infiltrating T lymphocytes for several solid tumours across diverse patient cohorts. To investigate the clinical relevance of tumour-infiltrating memory T lymphocytes, we investigated relevant publications to identify the significance of memory tumour-infiltrating T lymphocytes (TILs) in predicting survival in cancer patients and analysed the influence of variations in the tumour stage and the infiltrated location thereon.

METHODS

Relevant publications that assessed the clinical relevance of memory TILs to the patient's overall survival (OS) were investigated. Disease-free survival (DFS) was also evaluated where possible. Hazard ratios (HR) and 95% confidence intervals (CI) were assessed using a random-effects model. Heterogeneity was investigated with stratified analysis and I(2) statistics.

RESULTS

In total, 16 relevant publications, including 4248 cancer patients, were analysed. In the pooled analysis, intra-tumour accumulation of memory TILs correlated positively with favourable clinical outcomes for both OS (pooled HR, 2.06; 95% CI, 1.76-2.40) and DFS (pooled HR, 2.31; 95% CI, 1.67-3.19). Various effects of the tumour stage and the anatomical region where the cells infiltrated were identified in survival prediction, using memory TILs.

CONCLUSIONS

Overall, infiltration of memory TILs can serve as a biomarker for survival prediction in cancer. Additional heterogeneous effects of the associated factors should be considered when categorizing high-risk patients.

Dendritic cell vaccination, immune regulation, and clinical outcomes in ovarian cancer

Clinical optimism for dendritic cell vaccination against ovarian cancer has been tempered by the knowledge that tumors avail themselves of multiple mechanisms of immune evasion, thus blunting the efficacy of therapeutic vaccination. Mechanisms of immune suppression include infiltration by regulatory T cells (Treg) and myeloid suppressor cell populations, expression of co-inhibitory receptors, and expression of indoleamine 2,3-dioxygenase (IDO). Expression of both B7-H1 and IDO are associated with differentiation and recruitment of Treg, and clinical studies have shown that each of these mechanisms correlates independently with increased morbidity and mortality in ovarian cancer patients. In sharp contrast, recent studies have indicated that Th17 cell infiltration in ovarian cancer correlates with improved patient outcomes and prolonged overall survival. Given that IDO plays a pivotal role in the balance between Treg and Th17 immunity, elucidation of the mechanisms that regulate IDO activity and immune suppression may lead to novel adjuvants to boost the clinical efficacy of dendritic cell vaccination against ovarian cancer and other malignancies.

Chemoimmunotherapy using pegylated liposomal Doxorubicin and interleukin-18 in recurrent ovarian cancer: a phase I dose-escalation study

Recombinant interleukin (IL)-18 (SB-485232) is an immunostimulatory cytokine, with shown antitumor activity in combination with pegylated liposomal doxorubicin (PLD) in preclinical models. This phase I study evaluated the safety, tolerability, and biologic activity of SB-485232 administered in combination with PLD in subjects with recurrent ovarian cancer. The protocol comprised four cycles of PLD (40 mg/m(2)) on day 1 every 28 days, in combination with SB-485232 at increasing doses (1, 3, 10, 30, and 100 μg/kg) on days 2 and 9 of each cycle, to be administered over five subject cohorts, followed by discretionary PLD monotherapy. Sixteen subjects were enrolled. One subject withdrew due to PLD hypersensitivity. Most subjects (82%) were platinum-resistant or refractory, and had received a median of three or more prior chemotherapy regimens. SB-485232 up to 100 μg/kg with PLD had an acceptable safety profile. Common drug-related adverse events were grade 1 or 2 (no grade 4 or 5 adverse events). Concomitant PLD administration did not attenuate the biologic activity of IL-18, with maximal SB-485232 biologic activity already observed at 3 μg/kg. Ten of 16 enrolled subjects (63%) completed treatment, whereas five (31%) subjects progressed on treatment. A 6% partial objective response rate and a 38% stable disease rate were observed. We provide pilot data suggesting that SB-485232 at the 3 μg/kg dose level in combination with PLD is safe and biologically active. This combination warrants further study in a phase II trial.

Therapeutic vaccines for ovarian cancer

While therapeutic vaccines for ovarian cancer represent only a small fraction of active clinical trials, growing interest in this area and the accumulated data supporting the use of vaccines in cancer treatment portend further expansion of trials incorporating these strategies. This review explores the rationale for the use of vaccines for the treatment of ovarian cancer. It examines vaccine platforms that have been investigated and reviews the data from these studies. We also highlight recently reported phase 2 and 3 clinical trials with clinical outcomes as endpoints. Finally, we consider directions for the next generation of vaccines in light of these findings and our emerging understanding of agents that may augment vaccine responses by targeting the immunosuppressive impact of the tumor microenvironment.

Emerging therapeutic biomarkers in endometrial cancer

Although clinical trials of molecular therapies targeting critical biomarkers (mTOR, epidermal growth factor receptor/epidermal growth factor receptor 2, and vascular endothelial growth factor) in endometrial cancer show modest effects, there are still challenges that might remain regarding primary/acquired drug resistance and unexpected side effects on normal tissues. New studies that aim to target both genetic and epigenetic alterations (noncoding microRNA) underlying malignant properties of tumor cells and to specifically attack tumor cells using cell surface markers overexpressed in tumor tissue are emerging. More importantly, strategies that disrupt the cancer stem cell/epithelial-mesenchymal transition-dependent signals and reactivate antitumor immune responses would bring new hope for complete elimination of all cell compartments in endometrial cancer. We briefly review the current status of molecular therapies tested in clinical trials and mainly discuss the potential therapeutic candidates that are possibly used to develop more effective and specific therapies against endometrial cancer progression and metastasis.

[Immunological analogies between ovarian cancer and pregnancy]

During pregnancy an environment allowing installation of tolerance toward the fetus is set up locally at the materno-fetal interface. Numerous effectors of immunity are involved in this tolerance (NK cell, T cell, Macrophages, dendritic cell). Specific mechanisms during pregnancy attract locally these immunological cells. In the decidua, they are educated toward tolerance. These mechanisms evolve during the pregnancy because at the end of the pregnancy, tolerance is broken to prepare and activate the labor. Ovarian tumors, after having surmounted the immunosurveillance, like trophoblast, chair the installation of a tolerance of their host facilitating the development of the disease. The blocking of these mechanisms of tolerance coupled with activation of mechanisms of defenses offer new perspectives in the treatment of the ovarian cancer. The authors suggest showing the analogies of the tolerance observed during ovarian cancer and pregnancy. The knowledge of the orchestration of the physiological mechanisms observed during pregnancy will offer new therapeutic targets.

Expression of death receptor 6 by ovarian tumors in laying hens, a preclinical model of spontaneous ovarian cancer

Tumor-associated neoangiogenesis and suppression of antitumor immunity are hallmarks of tumor development and progression. Death receptor 6 (DR6) has been reported to be associated with suppression of antitumor immunity and tumor progression in several malignancies. However, expression of DR6 by malignant ovarian epithelial tumors at an early stage is unknown. The goals of this study were to determine whether DR6 is expressed by malignant ovarian epithelial tumors at an early stage and to examine whether DR6 expression is associated with ovarian cancer (OVCA) progression in a laying hen model of spontaneous OVCA. Expression of DR6 was examined in normal and malignant ovaries, normal ovarian surface epithelial (OSE) cells, or malignant epithelial cells and in serum of 3-year-old hens. The population of microvessels expressing DR6 was significantly higher in hens with early-stage OVCA than hens with normal ovaries (P < .01) and increased further in late-stage OVCA. The results of this study showed that, in addition to microvessels, tumor cells in the ovary also express DR6 with a significantly higher intensity than normal OSE cells. Similar patterns of DR6 expression were also observed by immunoblot analysis and gene expression studies. Furthermore, DR6 was also detected in the serum of hens. In conclusion, DR6 expression is associated with OVCA development and progression in laying hens. This study may be helpful to examine the feasibility of DR6 as a useful surrogate marker of OVCA, a target for antitumor immunotherapy and molecular imaging and thus provide a foundation for clinical studies.

Prognostic significance of tumor-infiltrating T cells in ovarian cancer: a meta-analysis

OBJECTIVE

The presence of T cells within the epithelial component of tumors, as histologic evidence of anti-tumor immunity, has been associated with a survival advantage in multiple studies across diverse patient cohorts. We performed a meta-analysis of studies evaluating the prognostic value of tumor-infiltrating lymphocytes (TIL) on survival among women with ovarian cancer and to investigate factors associated with variations in this effect, including patient characteristics, surgical outcomes, tumor histology, and study protocols.

METHOD

Published studies that evaluated the association between TIL and patient survival were identified. Descriptive statistics, outcome data, and study quality were extracted from studies that met inclusion criteria. Hazard ratios and 95% confidence intervals were pooled across studies using the random-effects model. Publication bias was investigated using a funnel plot and heterogeneity was assessed with subgroup analysis and I(2) statistics.

RESULTS

Ten suitable studies comprising 1815 patients with ovarian cancer were analyzed. Our results demonstrate that a lack of intraepithelial TILs is significantly associated with a worse survival among patients (pooled HR: 2.24, 95% CI; 1.71-2.91). Variations in the prognostic value of TIL status based on debulking status, scoring method, and geographic regions were identified.

CONCLUSIONS

Intraepithelial TILs are a robust predictor of outcome in ovarian cancer and define a specific class of patients, whose distinct tumor biology should be taken into account in devising appropriate therapeutic strategies.

Time-dependent cytotoxic drugs selectively cooperate with IL-18 for cancer chemo-immunotherapy

Background

Time-dependent chemotherapeutic agents can selectively target tumor cells in susceptible phases of the cell cycle however a fraction of tumor cells in non-vulnerable cell cycle phases remain drug-resistant. Immunotherapy represents a promising approach to overcome the limitation of phase-specific drugs and improve their clinical efficacy. Here, we investigated the potential use of anticancer chemotherapeutic drugs in combination with IL-18, a cytokine with strong immunostimulatory properties.

Methods

Four chemotherapeutic drugs commonly used in ovarian cancer were first tested for the ability to increase the immunogenicity and killing of the murine ovarian cancer cell line ID8 in vitro. Chemotherapeutric agents with measured time-dependent immune-enhancing effects were then tested for antitumor effectiveness in vivo in combination with IL-18 immunotherapy using the ID8-Vegf ovarian cancer model.

Results

Paclitaxel or topotecan exposure alone mediated incomplete, time-dependent killing against the murine ovarian cancer cell line ID8 in vitro, whereas carboplatin or gemcitabine mediated comprehensive, dose-dependent killing. In the plateau phase of the time-dependent killing by topotecan or paclitaxel, drug-resistant ID8 cells were more immunogenic with elevated expression of MHC-I and Fas, and increased sensitivity to CTL and Fas agonistic antibody in vitro. Moreover, the antitumor effectiveness of time-dependent agents in vivo was significantly improved with the addition of IL-18 through a T cell-dependent mechanism, while the effectiveness of drugs without significant phase specificity were not.

Conclusions

Tumor immunotherapy with IL-18 can significantly augment the killing fraction of phase-specific chemotherapeutic drugs and provide survival benefit. The safety profile of IL-18 and its positive interactions with select anticancer chemotherapeutic agents strongly supports the clinical investigation of this combinatorial approach.

Dendritic cell vaccination against ovarian cancer--tipping the Treg/TH17 balance to therapeutic advantage?

The pathology of ovarian cancer is characterized by profound immunosuppression in the tumor microenvironment. Mechanisms that contribute to the immunosuppressed state include tumor infiltration by regulatory T cells (Treg), expression of B7-H1 (PDL-1), which can promote T cell anergy and apoptosis through engagement of PD-1 expressed by effector T cells, and expression of indoleamine 2,3-dioxygenase (IDO), which can also contribute to effector T cell anergy. Expression of both B7-H1 and IDO has been associated with differentiation and recruitment of Treg, and clinical studies have shown that each of these mechanisms correlates independently with increased morbidity and mortality in patients with ovarian cancer. In a remarkable counterpoint to these observations, ovarian tumor infiltration with T(H)17 cells correlates with markedly improved clinical outcomes. In this Future Perspectives review, we argue that dendritic cell (DC) vaccination designed to drive tumor-antigen-specific T(H)17 T cell responses, combined with adjuvant treatments that abrogate immunosuppressive mechanisms operative in the tumor microenvironment, offers the potential for clinical benefit in the treatment of ovarian cancer. We also discuss pharmacological approaches to modulation of MAP kinase signaling for manipulation of the functional plasticity of DC, such that they may be directed to promote T(H)17 responses following DC vaccination.

Wilms' Tumour gene 1 (WT1) as an immunotherapeutic target

High grade uterine sarcoma and recurrent endometrial carcinoma are aggressive cancers with limited treatment options, resulting in a poor prognosis. In this research we focused in the first place on the detection of a highly immunogenic tumour-associated antigen Wilms' tumour gene 1 (WT1) in uterine tumours. We were able to reveal its overexpression in the tumour cells of high grade sarcomas and carcinosarcomas . Moreover, patients with WT1 positive tumours had a significantly worse prognosis than patients who were WT1 negative. For carcinomas, WT1 was present in only a minority of tumour cells, but in the majority of intratumoural blood vessels. Small blood vessels in the normal tissue surrounding the carcinoma were also WT1 positive, suggesting a role for WT1 in angiogenesis. WT1 was hardly expressed or absent in the non-tumour or benign tumoural uterus (myoma, polyp). The next step was to develop a targeted treatment against WT1. We opted for dendritic cell (DC) based immunotherapy. Nevertheless a basal expression of WT1 in monocytes and in vitro cultured unloaded DC was observed, the electroporation of in vitro cultured DC with WT1-mRNA resulted in a higher expression of WT1 by the DC. WT1-mRNA loaded DC were used for in vivo stimulations of T cells, resulting in the rise of WT1-specific T cells and a transient molecular response (decrease of CA125) in an end stage endometrial carcinoma patient. No toxic side effects were reported. Future in vivo research, carried out in a phase I clinical trial in our center, will reveal the ability of this new therapy to induce an immunological and possible clinical response in WT1 positive uterine cancer patients.

Ovarian cancer creates a suppressive microenvironment to escape immune elimination

BACKGROUND

Considering the high mortality rate of ovarian cancer due to the absence of curative treatment in advanced stage or at recurrence, new therapeutic strategies are urgently needed. Immunotherapy is one of these strategies that yielded promising results in fundamental and animal research in the past years. However, implementation in clinical practice remains poor. The aim of this review is to gain insight into the mechanisms of interaction between ovarian cancer and the immune system in order to develop better immunotherapeutic strategies.

METHODS

We searched the published literature for studies focusing on interactions between ovarian cancer and the immune system, with emphasis on outcome data in order to create a knowledge base that is well grounded in clinical reality.

RESULTS

The immunological response against cancer is a critical balance between immune-activating and immune-suppressing mechanisms. Besides the immune-activating tumor infiltrating lymphocytes (TILs), immune-suppressive regulatory T-cells (Tregs), tolerance-inducing plasmacytoid dendritic cells (pDCs), B7-H4+ macrophages, immune-suppressive cytokines such as IL10 and TGF-beta are also found in the tumor environment. Myeloid-derived suppressive cells (MDSCs) are recently found to have a significant role in immune suppression in ovarian cancer in murine studies. Furthermore, vascular endothelial growth factor (VEGF) is also known to have an immune-suppressing role besides its angiogenic role. All those concerted mechanisms result in the creation of an environment where the cancer is invincible and can grow unhampered.

CONCLUSION

Further knowledge of the mechanisms involved is needed to develop better strategies and improve the clinical applicability of immunotherapy. Effective immunotherapy must combine immune-activating strategies with elimination of immune-suppressing mechanisms. We believe that tilting the balance from an immune-suppressive to an immune-active environment may have an enormous impact on the disease.