Immunologic approaches to ovarian cancer treatment

IGF1R Axis Inhibition Restores Dendritic Cell Antitumor Response in Ovarian Cancer

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy. The insulin-like growth factor (IGF) system plays a key role in regulating growth and invasiveness in several malignancies, including ovarian cancer. IGF1R targeting showed antiproliferative activity of EOC cells. However, clinical studies failed to show significant benefit. EOC cells suppress antitumor immune responses by inducing dendritic cell (DC) dysfunction. The IGF1 axis can regulate DC maturation. The current study evaluated involvement of the IGF1 axis in DC differentiation in EOC. Studies were conducted on EOC and on a human monocyte cell line. Tissue microarray analysis (TMA) was performed on 36 paraffin blocks from EOC patients. Expression of IGF1R, p53, Ki67, BRCA1, and DC markers was evaluated using immunohistochemistry. Co-culture of EOC cells with DC pretreated with IGF1R inhibitor blocked cancer cell migration. TMA demonstrated higher rate of IGF1R protein expression in patients with advanced (76.9%) as compared to early (40%) EOC. A negative correlation between IGF1R protein expression and the CD1c marker was found. These findings provide evidence that IGF1R axis inhibition could be a therapeutic strategy for ovarian cancer by restoring DC-mediated antitumor immunity.

Safety, immunogenicity, and clinical efficacy of durvalumab in combination with folate receptor alpha vaccine TPIV200 in patients with advanced ovarian cancer: a phase II trial

BACKGROUND

Immune checkpoint inhibitors (ICIs) to date have demonstrated limited activity in advanced ovarian cancer (OC). Folate receptor alpha (FRα) is overexpressed in the majority of OCs and presents an attractive target for a combination immunotherapy to potentially overcome resistance to ICI in OCs. The current study sought to examine clinical and immunologic responses to TPIV200, a multiepitope FRα vaccine administered with programmed death ligand 1 (PD-L1) inhibitor durvalumab in patients with advanced platinum-resistant OC.

METHODS

Following Simon two-stage phase II trial design, 27 patients were enrolled. Treatment was administered in 28-day cycles (intradermal TPIV200 and granulocyte-macrophage colony-stimulating factor (GM-CSF) for 6 cycles and intravenous durvalumab for 12 cycles). Primary endpoints included overall response rate and progression-free survival at 24 weeks. Translational parameters focused on tumor microenvironment, PD-L1 and FRα expression, and peripheral vaccine-specific immune responses.

RESULTS

Treatment was well tolerated, with related grade 3 toxicity rate of 18.5%. Increased T cell responses to the majority of peptides were observed in all patients at 6 weeks (p<0.0001). There was one unconfirmed partial response (3.7%) and nine patients had stable disease (33.3%). Clinical benefit was not associated with baseline FRα or PD-L1 expression. One patient with prolonged clinical benefit demonstrated loss of FRα expression and upregulation of PD-L1 in a progressing lesion. Despite the low overall response rate, the median overall survival was 21 months (13.5-∞), with evidence of benefit from postimmunotherapy regimens.

CONCLUSIONS

Combination of TPIV200 and durvalumab was safe and elicited robust FRα-specific T cell responses in all patients. Unexpectedly durable survival in this heavily pretreated population highlights the need to investigate the impact of FRα vaccination on the OC biology post-treatment.

IL-12 Expressing oncolytic herpes simplex virus promotes anti-tumor activity and immunologic control of metastatic ovarian cancer in mice

Background

Despite advances in surgical aggressiveness and conventional chemotherapy, ovarian cancer remains the most lethal cause of gynecologic cancer mortality; consequently there is a need for new therapeutic agents and innovative treatment paradigms for the treatment of ovarian cancer. Several studies have demonstrated that ovarian cancer is an immunogenic disease and immunotherapy represents a promising and novel approach that has not been completely evaluated in ovarian cancer. Our objective was to evaluate the anti-tumor activity of an oncolytic herpes simplex virus “armed” with murine interleukin-12 and its ability to elicit tumor-specific immune responses. We evaluated the ability of interleukin−12-expressing and control oncolytic herpes simplex virus to kill murine and human ovarian cancer cell lines in vitro. We also administered interleukin−12-expressing oncolytic herpes simplex virus to the peritoneal cavity of mice that had developed spontaneous, metastatic ovarian cancer and determined overall survival and tumor burden at 95 days. We used flow cytometry to quantify the tumor antigen-specific CD8⁺ T cell response in the omentum and peritoneal cavity.

Results

All ovarian cancer cell lines demonstrated susceptibility to oncolytic herpes simplex virus in vitro. Compared to controls, mice treated with interleukin−12-expressing oncolytic herpes simplex virus demonstrated a more robust tumor antigen-specific CD8⁺ T-cell immune response in the omentum (471.6 cells vs 33.1 cells; p = 0.02) and peritoneal cavity (962.3 cells vs 179.5 cells; p = 0.05). Compared to controls, mice treated with interleukin−12-expressing oncolytic herpes simplex virus were more likely to control ovarian cancer metastases (81.2 % vs 18.2 %; p = 0.008) and had a significantly longer overall survival (p = 0.02). Finally, five of 6 mice treated with interleukin−12-expressing oHSV had no evidence of metastatic tumor when euthanized at 6 months, compared to two of 4 mice treated with sterile phosphate buffer solution.

Conclusion

Our pilot study demonstrates that an interleukin−12-expressing oncolytic herpes simplex virus effectively kills both murine and human ovarian cancer cell lines and promotes tumor antigen-specific CD8⁺ T-cell responses in the peritoneal cavity and omentum, leading to reduced peritoneal metastasis and improved survival in a mouse model.

Adoptive immunotherapy against ovarian cancer

The standard front-line therapy for epithelial ovarian cancer (EOC) is combination of debulking surgery and platinum-based chemotherapy. Nevertheless, the majority of patients experience disease recurrence. Although extensive efforts to find new therapeutic options, cancer cells invariably develop drug resistance and disease progression. New therapeutic strategies are needed to improve prognosis of patients with advanced EOC.

Recently, several preclinical and clinical studies investigated feasibility and activity of adoptive immunotherapy in EOC. Our aim is to highlight prospective of adoptive immunotherapy in EOC, focusing on HLA-restricted Tumor Infiltrating Lymphocytes (TILs), and MHC-independent immune effectors such as natural killer (NK), and cytokine-induced killer (CIK). Adoptive cell therapy (ACT) has shown activity in several pre-clinical models. Available preclinical and clinical data suggest that adoptive cell therapy may provide the best benefit in settings of low tumor burden, minimal residual disease, or maintenance therapy. Further studies are needed to better define the optimal clinical setting.

Leveraging immunotherapy for the treatment of gynecologic cancers in the era of precision medicine

During the past decade significant progress in the understanding of stimulatory and inhibitory signaling pathways in immune cells has reinvigorated the field of immuno-oncology. In this review we outline the current immunotherapy based approaches for the treatment of gynecological cancers, and focus on the emerging clinical data on immune checkpoint inhibitors, adoptive cell therapies, and vaccines. It is anticipated that in the coming years biomarker-guided clinical trials, will provide for a better understanding of the mechanisms of response and resistance to immunotherapy, and guide combination treatment strategies that will extend the benefit from immunotherapy to patients with gynecologic cancers.

Targeting myeloid cells in the tumor microenvironment enhances vaccine efficacy in murine epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is typically diagnosed at advanced stages, and is associated with a high relapse rate. Patients in remission are ideal candidates for immunotherapy aimed at cure or prolonging disease-free periods. However, immunosuppressive pathways in the tumor microenvironment are obstacles to durable anti-tumor immunity. In a metastatic syngeneic mouse model of EOC, immunosuppressive macrophages and myeloid-derived suppressor cells (MDSCs) accumulate in the local tumor environment. In addition, resident peritoneal macrophages from non-tumor-bearing mice were highly immunosuppressive, abrogating stimulated T cell proliferation in a cell contact-dependent manner. Immunization with microparticles containing TLR9 and NOD-2 ligands (MIS416) significantly prolonged survival in tumor-bearing mice. The strategy of MIS416 immunization followed by anti-CD11b administration further delayed tumor progression, thereby establishing the proof of principle that myeloid depletion can enhance vaccine efficacy. In patients with advanced EOC, ascites analysis showed substantial heterogeneity in the relative proportions of myeloid subsets and their immunosuppressive properties. Together, these findings point to immunosuppressive myeloid cells in the EOC microenvironment as targets to enhance vaccination. Further studies of myeloid cell accumulation and functional phenotypes in the EOC microenvironment may identify patients who are likely to benefit from vaccination combined with approaches that deplete tumor-associated myeloid cells.

Prognostic impact of human leukocyte antigen class I expression and association of platinum resistance with immunologic profiles in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is one of the most deadly carcinomas in females. Immune systems can recognize EOCs; however, a defect of human leukocyte antigen (HLA) class I expression is known to be a major mechanism for escape from immune systems, resulting in poor prognosis. The purpose of this study is to identify novel correlations between immunologic responses and other clinical factors. We investigated the expression of immunologic components in 122 cases of EOCs for which surgical operations were performed between 2001 and 2011. We immunohistochemically stained EOC specimens using an anti-pan HLA class I monoclonal antibody (EMR8-5) and anti-CD3, -CD4, and -CD8 antibodies, and we analyzed correlations between immunologic parameters and clinical factors. In multivariate analysis that used the Cox proportional hazards model, independent prognostic factors for overall survival in advanced EOCs included low expression level of HLA class I [risk ratio (RR), 1.97; 95% confidence interval (CI), 1.01-3.83; P = 0.046] and loss of intraepithelial cytotoxic T lymphocyte (CTL) infiltration (RR, 2.11; 95% CI, 1.06-4.20; P = 0.033). Interestingly, almost all platinum-resistant cases showed a significantly low rate of intraepithelial CTL infiltration in the χ(2) test (positive vs. negative: 9.0% vs. 97.7%; P < 0.001). Results from a logistic regression model revealed that low CTL infiltration rate was an independent factor of platinum resistance in multivariate analysis (OR, 3.77; 95% CI, 1.08-13.12; P = 0.037). Platinum-resistant EOCs show poor immunologic responses. The immune escape system of EOCs may be one of the mechanisms of platinum resistance.

Interferon regulatory factor 1 is an independent predictor of platinum resistance and survival in high-grade serous ovarian carcinoma

OBJECTIVE

High-grade serous ovarian cancer (HGSOC) that is resistant to platinum-based chemotherapy has a particularly poor prognosis. Response to platinum has both prognostic survival value and dictates secondary treatment strategies. Using transcriptome analysis, we sought to identify differentially expressed genes/pathways based on a tumor's platinum response for discovering novel predictive biomarkers.

METHODS

Seven primary HGSOC tumor samples, representing two extremes of platinum sensitivity/timing of disease recurrence, were analyzed by RNA-Seq, Ingenuity Pathways Analysis (IPA) and Upstream Regulator Analysis (URA), and used to explore differentially expressed genes and prevalent molecular and cellular processes. Progression-free and overall survival (PFS, OS) was estimated using the Kaplan-Meier method in two different sample sets including GEO and TCGA data sets.

RESULTS

IPA and URA highlighted an IRF1-driven transcriptional program (P=0.0017; z-score of 3.091) in the platinum sensitive improved PFS group. QRT-PCR analysis of 31 HGSOC samples demonstrated a significant difference in PFS between low and high IRF1 expression groups (P=0.048) and between groups that were platinum sensitive versus not (P=0.016). In a larger validation data set, increased levels of IRF1 were associated with both increased PFS (P=0.043) and OS (P=0.019) and the effect on OS was independent of debulking status (optimal debulking, P=0.025; suboptimal, P=0.041).

CONCLUSION

Transcriptome analysis identifies IRF1, a transcription factor that functions both in immune regulation and as a tumor suppressor, as being associated with platinum sensitivity and an independent predictor of both PFS and OS in HGSOC.

Developmentally restricted differentiation antigens are targets for immunotherapy in epithelial ovarian carcinoma

Developmentally restricted differentiation antigens or cancer-placental antigens, tastin and bystin, are components of an adhesion molecule that plays a critical role in the implantation of the embryo to the uterus. Cell adhesion molecules have been implicated in the metastasis of carcinomas and could be critical targets for immunotherapy in epithelial ovarian carcinomas (EOCs). Our objectives were to define the expression of tastin and bystin proteins in EOCs. Expression of tastin and bystin mRNA in a panel of human tissues and 70 EOC specimens was investigated using qualitative polymerase chain reaction. Amplification products were confirmed by sequencing. Validation of results was performed using immunohistochemical analysis of tastin and bystin applied on a tissue microarray of 202 EOC tissues. The distribution of tastin and bystin expression and clinicopathologic variables were analyzed. Survival probabilities were estimated using the Kaplan-Meier method and statistical significance was determined by performing the logrank test. Expression of tastin and bystin was restricted to placental and testis tissue by qualitative polymerase chain reaction. Of the 70 EOC specimens tested with polymerase chain reaction, 89% and 94% expressed tastin and bystin, respectively. Immunoexpressions of tastin and bystin protein were observed in 69% and 80 % of the ovarian tumors, respectively. Tastin and bystin expression in Stage I/II disease were 66% and 67% compared with 69% and 81% in Stage III/IV disease, respectively. The tissue-restricted expression of tastin and bystin and their abundant expression in EOCs and advanced-stage disease make these developmentally restricted antigens attractive targets for antigen-specific immunotherapy in EOCs.

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.

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.

Phase I/II randomized trial of dendritic cell vaccination with or without cyclophosphamide for consolidation therapy of advanced ovarian cancer in first or second remission

PURPOSE

In spite of increased rates of complete response to initial chemotherapy, most patients with advanced ovarian cancer relapse and succumb to progressive disease. Immunotherapy may have potential for consolidation therapy.

EXPERIMENTAL DESIGN

This randomized open-label phase I/II trial evaluated responses of patients with advanced ovarian cancer in remission for vaccination with monocyte-derived dendritic cells (DC) loaded with Her2/neu, hTERT, and PADRE peptides, with or without low-dose intravenous cyclophosphamide. All patients also received pneumococcal vaccine and were randomized to cyclophosphamide 2 days prior to first vaccination. Blood samples were analyzed by ELISPOT and flow cytometry.

RESULTS

Of 11 patients, 2 recurred during vaccination. Nine received all 4 doses: 3 patients recurred at 6, 17, and 26 months, respectively, and 6 have no evidence of disease at 36 months. No grade 3/4 vaccine-related toxicities were noted. The 3-year overall survival was 90%. Patients receiving cyclophosphamide showed a non-significant improvement in survival over controls. Patients receiving cyclophosphamide had a transient reduction in neutrophils, but no change in total lymphocytes or regulatory T cells. Modest T-cell responses to Her2/neu and hTERT were seen post-vaccine by IFN-γ ELISPOT. Patients demonstrated below normal responses to the diphtheria conjugate protein CRM197, a component of the pneumococcal vaccine.

CONCLUSIONS

In this setting, peptide-loaded DC vaccination elicits modest immune responses, but survival is promising. Pneumococcal vaccination revealed substantial immune suppression, even in patients in remission. Rational design of consolidative strategies for ovarian cancer will need to overcome tolerance and immunosuppression.

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.

Indoleamine 2,3-dioxygenase and immune tolerance in ovarian cancer

PURPOSE OF REVIEW

Ovarian cancer is the leading cause of cancer death among gynecologic malignancies despite significant advances in cytoreductive surgery and chemotherapy, and novel therapeutic approaches are urgently needed. Immunotherapy is one of these strategies; however, its clinical applications have shown limited efficacy. This may be attributed to tumor-induced immune tolerance, and much attention has been paid to overcoming these immune resistance mechanisms. This review focuses on the immunoregulatory enzyme indoleamine 2,3-dioxygenase (IDO) and shows the role of IDO and its clinical potential in ovarian cancer.

RECENT FINDINGS

IDO suppresses the proliferation of effector T cells or natural killer cells and their killer functions. In ovarian cancer, high IDO expression in tumor cells was correlated with a reduced number of tumor-infiltrating lymphocytes. The IDO expression was also correlated with advanced surgical stage and impaired survival. Preclinical studies in mice demonstrated that oral administration of IDO inhibitors suppressed peritoneal dissemination and potentiated the antitumor efficacy of chemotherapeutic agents.

SUMMARY

IDO induces immune tolerance and promotes ovarian cancer progression. Tumoral IDO expression is correlated with impaired clinical outcome. IDO inhibition may therefore be a promising strategy to restore host antitumor immunity and to enhance the antitumor potential of current chemotherapy or immunotherapy for advanced ovarian cancer.

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.

Regulation of cancer germline antigen gene expression: implications for cancer immunotherapy

Cancer germline (CG; also known as cancer-testis) antigen genes are normally expressed in germ cells and trophoblast tissues and are aberrantly expressed in a variety of human malignancies. CG antigen genes have high clinical relevance as they encode a class of immunogenic and highly selective tumor antigens. CG antigen-directed immunotherapy is undergoing clinical evaluation for the treatment of a number of solid tumor malignancies and has been demonstrated to be safe, provoke immune responses and be of therapeutic benefit. Achieving an improved understanding of the mechanisms of CG antigen gene regulation will facilitate the continued development of targeted therapeutic approaches against tumors expressing these antigens. Substantial evidence suggests epigenetic mechanisms, particularly DNA methylation, as a primary regulator of CG antigen gene expression in normal and cancer cells as well as in stem cells. The roles of sequence-specific transcription factors and signal transduction pathways in controlling CG antigen gene expression are less clear but are emerging. A combinatorial therapeutic approach involving epigenetic modulatory drugs and CG antigen immunotherapy is suggested based on these data and is being actively pursued. In this article, we review the mechanisms of CG antigen gene regulation and discuss the implications of these mechanisms for the development of cancer immunotherapy approaches targeting CG antigens.

Activated local immunity by CC chemokine ligand 19-transduced embryonic endothelial progenitor cells suppresses metastasis of murine ovarian cancer

Although tumor microenvironments play a key role in successful tumor immunotherapy, effective manipulation of local immunity is difficult because of the lack of an appropriate target system. It is well known that bone marrow-derived endothelial progenitor cells (EPCs) are actively recruited during tumor angiogenesis. Using this feature, we attempted to establish a novel therapeutic modality that targets tumor vessels of multiple metastases using embryonic endothelial progenitor cells (eEPCs) transduced with an immune-activating gene. The eEPCs were retrovirally transduced with the mouse CC chemokine ligand 19 (CCL19) gene, a lymphocyte-migrating chemokine. The mouse ovarian cancer cell line OV2944-HM-1 (HM-1) was inoculated subcutaneously into B6C3F1 mice, along with CCL19-tranduced eEPCs (eEPC-CCL19), resulting in immunologic activity and tumor-inhibitory effects. In this model, eEPC-CCL19 showed tumor repression accompanied by increased tumor-infiltrating CD8+ lymphocytes compared with the control group. In contrast, no tumor repression was observed when the same experiment was done in immunodeficient (SCID) mice, suggesting a crucial role of T-cell function in this system. Next, we established a lung metastasis model by injecting HM-1 cells or B16 melanoma cells via the tail vein. Subsequent intravenous injection of eEPC-CCL19 leads to a decrease in the number of lung metastasis and prolonged survival. Antitumor effects were also observed in a peritoneal dissemination model using HM-1. These results suggest that systemic delivery of an immune-activating signal using EPCs can alter the tumor immune microenvironment and lead to a therapeutic effect, which may provide a novel strategy for targeting multiple metastases of various malignancies.

Consolidation Therapy in Ovarian Cancer: A Clinical Update

Objectives:

To evaluate current strategies under investigation for use as consolidation or maintenance treatment in patients with ovarian cancer.

Patients with epithelial ovarian cancer often enter a complete remission after primary treatment. Many relapse, unfortunately, but some can return to remission after additional treatment. Outcomes can be improved by applying effective consolidation or maintenance approaches to patients in a complete primary or subsequent remission.

Methods:

A selective review of the literature is undertaken to consider strategies that are being or will likely be evaluated in randomized trials while we assess whether consolidation or maintenance will have a place in the treatment of patients with ovarian cancer.

Results:

The application of extended standard cytotoxic agents has been generally disappointing, and no strategy applied in the first remission setting has prolonged overall survival.

Conclusions:

As treatment options move beyond classic chemotherapy to novel hormones, immune interventions, and biologic agents, the consolidation strategy is regaining interest. This is particularly attractive in that many of these agents have stable disease as best outcome, and this is most appropriate to evaluate in patients with minimal volume disease. A consideration of toxicity is paramount, and any strategy to be considered in an otherwise asymptomatic patient in remission must be well tolerated. In addition, patients in second or third complete remission are also being considered as an appropriate group in which to evaluate new agents. Numerous other phase 2 trials with novel agents not considered here are underway, and it is to be hoped that some will emerge as contenders for randomized trials. Participation in these trials remains a priority for patients who otherwise must pursue a difficult watch-and-wait strategy.

Intraepithelial CD8-positive T lymphocytes predict survival for patients with serous stage III ovarian carcinomas: relevance of clonal selection of T lymphocytes

Background:

The aim of this study was to investigate the prognostic effect of tumour-infiltrating lymphocytes (TILs) in serous stage III ovarian carcinoma to determine TIL clonality and to correlate this to Her2/neu expression.

Methods:

Formalin-fixed and paraffin-embedded ovarian carcinomas were examined for CD20-, CD3-, CD4- and CD8-positive lymphocytes (n=100), and for Her2/neu-positive tumour cells (n=55/100) by immunohistochemistry. Clonality analysis was carried out by T-cell receptor γ (TCRγ) gene rearrangements (n=93/100). Statistical analyses included experimental and clinico-pathological variables, as well as disease-free (DFS) and overall (OS) survival.

Results:

CD20-positive B lymphocytes were present in 57.7% (stromal)/33.0% (intraepithelial) and CD3-positive T lymphocytes in 99.0% (stromal)/90.2% (intraepithelial) of ovarian carcinomas. Intraepithelial CD3-positive T lymphocytes were correlated with improved DFS in optimally debulked patients (P=0.0402). Intraepithelial CD8-positive T lymphocytes were correlated with improved OS in all optimally debulked patients (P=0.0201) and in those undergoing paclitaxel/carboplatin therapy (P=0.0092). Finally, rarified and clonal TCRγ gene rearrangements were detected in 37 out of 93 (39.8%) and 15 out of 93 (16.1%) cases, respectively. This was marginally associated with improved DFS (P=0.0873). Despite a significant correlation of HER2/neu status and intraepithelial CD8-positive lymphocytes (P=0.0264), this was non-directional (R=−0.257; P=0.0626).

Conclusion:

Improved survival of ovarian cancer patients is related to the infiltration, clonal selection and intraepithelial persistence of T lymphocytes.

Intraepithelial T cells and tumor proliferation: impact on the benefit from surgical cytoreduction in advanced serous ovarian cancer

BACKGROUND

The aim of the study was to determine whether tumor-infiltrating lymphocytes and/or tumor mitotic activity could identify subgroups of patients with advanced serous epithelial ovarian cancer who would maximally benefit from aggressive surgical cytoreduction.

METHODS

Snap-frozen specimens from 134 consecutive patients with stage III or IV serous or poorly differentiated ovarian adenocarcinoma undergoing primary debulking surgery from a single US institution were characterized based on CD3(+), CD8(+), FoxP3(+) tumor-infiltrating lymphocytes, and Ki67 expression. Kaplan-Meier survival curves were estimated and compared using a log-rank statistic. A multivariate Cox model was used to estimate adjusted hazard ratios. Interactions were modeled using recursive partitioning based on maximal prognostic differentiation.

RESULTS

Brisk intraepithelial CD8(+) cells (P = .035) and low Ki67 expression (P = .042) portended prolonged survival. The T-cell infiltration was more likely to occur in tumors with high proliferation index. Patients whose tumors exhibited low Ki67 expression and high intraepithelial CD8(+) frequency had a 5-year survival rate of 73.3%. Patients with aggressive tumor behavior, that is, whose tumors exhibited low frequency of intraepithelial CD8(+) T cells or high Ki67 expression were more likely to draw benefit from aggressive surgical cytoreduction. Survival was similar for patients with brisk CD8(+) T cells who had optimal or suboptimal debulking. Likewise, survival was similar for patients with low Ki67 expression who had optimal or suboptimal debulking.

CONCLUSIONS

For the first time, these novel interactions of T cells, tumor proliferation index, and surgical treatment reveal that biological prognosticators may be useful for surgical decision making in ovarian cancer.

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.

Clinical potential of mucins in diagnosis, prognosis, and therapy of ovarian cancer

Knowledge of mucins and their multiple roles in various normal and pathological processes has improved greatly in the past two decades. Mucins belong to a family of glycoproteins characterised by densely O-glycosylated repetitive domains and expressed by various surface epithelial cells. Altered expression of mucins is present in various diseases, including cancer. Ovarian cancer is the sixth most common cancer worldwide and the seventh leading cause of cancer-related deaths in women. The most common ovarian cancer is epithelial ovarian carcinoma, which is characterised by few early symptoms, widespread peritoneal dissemination, and ascites at advanced stages that result in poor prognosis. After diagnosis, 5 year survival is only 35-45%. Therefore, improved strategies for early diagnosis and treatment are needed. Because of the surface epithelial origin of epithelial ovarian cancer, mucins are obvious biomolecules for investigation as markers for early diagnosis and as therapeutic targets. We discuss the potential role and clinical usefulness of mucins in early diagnosis, prognosis, and treatment of ovarian cancer.

Prognostic implications of type and density of tumour-infiltrating lymphocytes in gastric cancer

The study aims to determine whether type and density of tumour-infiltrating lymphocytes (TILs) can predict the clinical course in gastric cancer. Gastric carcinomas (n=220) were immunostained for CD3, CD8, CD20, and CD45RO and evaluated for clinicopathologic characteristics. Number of TILs that immunostained positively for each marker were counted using NIH ImageJ software. Tumours were grouped into low- and high-density groups for each marker (CD3, CD8, CD45RO). The densities of CD3(+), CD8(+), and CD45RO(+) TILs were found to be independent predictors of lymph node metastasis by multivariate analysis with odds ratios (95% CI) of 0.425 (0.204-0.885), 0.325 (0.150-0.707), and 0.402 (0.190-0.850), respectively. Kaplan-Meier survival analysis revealed that patients in the high-density groups for CD3, CD8, and C45RO had a significantly longer survival time than the patients in the corresponding low-density groups, respectively. In multivariate survival analysis, the densities of CD3(+), CD8(+), and CD45RO(+) TILs remained independent prognostic factors with hazard ratios (95% CI) of 0.549 (0.317-0.951), 0.574 (0.347-0.949), and 0.507 (0.298-0.862), respectively. In conclusion, density of TILs was found to be independently predictive of regional lymph node metastasis and patient survival in gastric cancer.

Imaging immune response in vivo: cytolytic action of genetically altered T cells directed to glioblastoma multiforme

PURPOSE

Clinical trials have commenced to evaluate the feasibility of targeting malignant gliomas with genetically engineered CTLs delivered directly to the tumor bed in the central nervous system. The objective of this study is to determine a suite of magnetic resonance imaging (MRI) measurements using an orthotopic xenograft murine model that can noninvasively monitor immunologically mediated tumor regression and reactive changes in the surrounding brain parenchyma.

EXPERIMENTAL DESIGN

Our preclinical therapeutic platform is based on CTL genetic modification to express a membrane tethered interleukin-13 (IL-13) cytokine chimeric T-cell antigen receptor. This enables selective binding and signal transduction on encountering the glioma-restricted IL-13 alpha2 receptor (IL-13Ralpha2). We used MRI to visualize immune responses following adoptive transfer of IL-13Ralpha2-specific CD8+ CTL clones.

RESULTS

Based on MRI measurements, several phases following IL-13Ralpha2-specific T-cell adoptive transfer could be distinguished, all of which correlated well with glioblastoma regression confirmed on histology. The first detectable changes, 24 hours post-treatment, were significantly increased T2 relaxation times and strongly enhanced signal on T1-weighted postcontrast images. In the next phase, the apparent diffusion coefficient was significantly increased at 2 and 3 days post-treatment. In the last phase, at day 3 after IL-13Ralpha2-specific T-cell injection, the volume of hyperintense signal on T1-weighted postcontrast image was significantly decreased, whereas apparent diffusion coefficient remained elevated.

CONCLUSIONS

The present study indicates the feasibility of MRI to visualize different phases of immune response when IL-13Ralpha2-specific CTLs are administered directly to the glioma tumor bed. This will further the aim of better predicting clinical outcome following immunotherapy.

Evaluation of MHC class I peptide binding prediction servers: applications for vaccine research

Background

Protein antigens and their specific epitopes are formulation targets for epitope-based vaccines. A number of prediction servers are available for identification of peptides that bind major histocompatibility complex class I (MHC-I) molecules. The lack of standardized methodology and large number of human MHC-I molecules make the selection of appropriate prediction servers difficult. This study reports a comparative evaluation of thirty prediction servers for seven human MHC-I molecules.

Results

Of 147 individual predictors 39 have shown excellent, 47 good, 33 marginal, and 28 poor ability to classify binders from non-binders. The classifiers for HLA-A*0201, A*0301, A*1101, B*0702, B*0801, and B*1501 have excellent, and for A*2402 moderate classification accuracy. Sixteen prediction servers predict peptide binding affinity to MHC-I molecules with high accuracy; correlation coefficients ranging from r = 0.55 (B*0801) to r = 0.87 (A*0201).

Conclusion

Non-linear predictors outperform matrix-based predictors. Most predictors can be improved by non-linear transformations of their raw prediction scores. The best predictors of peptide binding are also best in prediction of T-cell epitopes. We propose a new standard for MHC-I binding prediction – a common scale for normalization of prediction scores, applicable to both experimental and predicted data. The results of this study provide assistance to researchers in selection of most adequate prediction tools and selection criteria that suit the needs of their projects.

In-vitro activation of cytotoxic T lymphocytes by fusion of mouse hepatocellular carcinoma cells and lymphotactin gene-modified dendritic cells

AIM

To investigate the in-vitro activation of cytotoxic T lymphocytes (CTLs) by fusion of mouse hepatocellular carcinoma (HCC) cells and lymphotactin gene-modified dendritic cells (DCs).

METHODS

Lymphotactin gene modified DCs (DCLptn) were prepared by lymphotactin recombinant adenovirus transduction of mature DCs which differentiated from mouse bone marrow cells by stimulation with granulocyte/macrophage colony-stimulating factor (GM-CSF), interleukin-4 (IL-4) and tumor necrosis factor alpha (TNF-alpha). DCLptn and H22 fusion was prepared using 50% PEG. Lymphotactin gene and protein expression levels were measured by RT-PCR and ELISA, respectively. Lymphotactin chemotactic responses were examined by in-vitro chemotaxis assay. In-vitro activation of CTLs by DCLptn/H22 fusion was measured by detecting CD25 expression and cytokine production after autologous T cell stimulation. Cytotoxic function of activated T lymphocytes stimulated with DCLptn/H22 cells was determined by LDH cytotoxicity assay.

RESULTS

Lymphotactin gene could be efficiently transduced to DCs by adenovirus vector and showed an effective biological activity. After fusion, the hybrid DCLptn/H22 cells acquired the phenotypes of both DCLptn and H22 cells. In T cell proliferation assay, flow cytometry showed a very high CD25 expression, and cytokine release assay showed a significantly higher concentration of IFN-gamma and IL-2 in DCLptn/H22 group than in DCLptn, DCLptn+H22, DC/H22 or H22 groups. Cytotoxicity assay revealed that T cells derived from DCLptn/H22 group had much higher anti-tumor activity than those derived from DCLptn, H22, DCLptn+H22, DC/H22 groups.

CONCLUSION

Lymphotactin gene-modified dendritoma induces T-cell proliferation and strong CTL reaction against allogenic HCC cells. Immunization-engineered fusion hybrid vaccine is an attractive strategy in prevention and treatment of HCC metastases.