Induction of tumour-specific CD8(+) cytotoxic T lymphocytes by tumour lysate-pulsed autologous dendritic cells in patients with uterine serous papillary 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.

Therapeutic vaccines and immune checkpoints inhibition options for gynecological cancers

Treatments for gynecological cancer include surgery, chemotherapy, and radiation. However, overall survival is not improved, and novel approaches are needed. Immunotherapy has been proven efficacious in various types of cancers and multiple approaches have been recently developed. Since numerous gynecological cancers are associated to human papilloma virus (HPV) infections, therapeutic vaccines, targeting HPV epitopes, have been developed. The advancing understanding of the immune system, regulatory pathways and tumor microenvironment have produced a major interest in immune checkpoint blockade, Indeed, immune checkpoint molecules are important clinical targets in a wide variety of tumors, including gynecological. In this review, we will describe the immunotherapeutic targets and modalities available and review the most recent immunotherapeutic clinical trials in the context of gynecological cancers. The synergic results obtained from the combination of HPV therapeutic vaccines with radiotherapy, chemotherapy, or immune checkpoint inhibitors, may underlie the potential for a novel therapeutic scenario for these tumors.

In Vitro Assessment of the Expression and T Cell Immunogenicity of the Tumor-Associated Antigens BORIS, MUC1, hTERT, MAGE-A3 and Sp17 in Uterine Cancer

Background: While immunotherapy moved to the forefront of treatment of various cancers, it remains underexplored for uterine cancer. This might be due to the small patient population with advanced endometrial carcinoma and uterine sarcoma. Data about immunotherapeutic targets are scarce in endometrial carcinoma and lacking in uterine sarcoma. Methods: Expression of five tumor-associated antigens (TAA) (BORIS, MUC1, hTERT, MAGE-A3 and Sp17) was validated in uterine tumor samples by immunohistochemistry (IHC) and/or quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). TAA immunogenicity was analyzed by determining spontaneous T cell responses towards overlapping peptide pools covering the whole TAA in patient blood. Results: At mRNA level, MAGE-A3 and Sp17 were overexpressed in a minority of patients and BORIS was moderately overexpressed (26% in endometrial carcinoma and 62% in uterine sarcoma). hTERT was overexpressed in the vast majority of tumors. On protein level, MUC1 was upregulated in primary, recurrent and metastatic EMCAR and in metastatic US tumors. hTERT protein was highly expressed in both normal and malignant tissue. Spontaneous TAA-specific T cell responses were detected in a minority of patients, except for hTERT to which T cell responses occurred more frequently. Conclusions: These data point to MUC1 and hTERT as most suitable targets based on expression levels and T cell immunogenicity for use in immunotherapeutic regimens.

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.

Immunotherapy: New Strategies for the Treatment of Gynecologic Malignancies

Over the past decade, the ability of cancer cells to evade immune destruction has become recognized as one of the hallmarks of cancer. This understanding has paved the way for the development of novel therapeutic agents that can enhance activation of antitumor immune responses or reverse immunosuppressive mechanisms through which tumors escape immune-mediated rejection. The treatment of gynecologic cancers remains a therapeutic challenge, as these malignancies are often diagnosed in advanced stages, and many patients relapse despite appropriate management. Clinical trials have shown efficacy for various immunotherapeutic strategies, especially the use of tumor-targeting antibodies; enhancement of tumor antigen presentation, such as with vaccines and toll-like receptor agonists; and the targeting of immunosuppressive mechanisms, such as via checkpoint blockade. Emerging data on new and combination approaches currently under investigation provide a strong rationale for these approaches.

Immunotherapy in endometrial cancer - an evolving therapeutic paradigm

Endometrial cancer is the only gynecologic malignancy with a rising incidence and mortality. While cure is routinely achieved with surgery alone or in combination with adjuvant pelvic radiotherapy when disease is confined to the uterus, patients with metastatic or recurrent disease exhibit limited response rates to cytotoxic chemotherapy, targeted agents, or hormonal therapy. Given the unmet clinical need in this patient population, exploration of novel therapeutic approaches is warranted, and attention is turning to immunomodulation of the tumor microenvironment. Existing evidence suggests that endometrial cancer is sufficiently immunogenic to be a reasonable candidate for active and/or passive immunotherapy. In this review, we critically examine what is known about the microenvironment in endometrial cancer and what has been learned from preliminary immunotherapy trials that enrolled endometrial cancer patients, encouraging further attempts at immunomodulation in the treatment of aggressive forms of this disease.

Dendritic cell immunotherapy in uterine cancer

Uterine cancer is the most common pelvic gynecological malignancy. Uterine sarcomas and relapsed uterine carcinomas have limited treatment options. The search for new therapies is urgent. Dendritic cell (DC) immunotherapy holds much promise, though has been poorly explored in uterine cancer. This commentary gives an insight in existing DC immunotherapy studies in uterine cancer and summarizes the possibilities and the importance of the loading of tumor antigens onto DC and their subsequent maturation. However, the sole application of DC immunotherapy to target uterine cancer will be insufficient because of tumor-induced immunosuppression, which will hamper the establishment of an effective anti-tumor immune response. The authors give an overview on the limited existing immunosuppressive data and propose a novel approach on DC immunotherapy in uterine cancer.

Polymerase ε (POLE) ultra-mutated tumors induce robust tumor-specific CD4+ T cell responses in endometrial cancer patients

OBJECTIVE

Around 7-10% of endometrial carcinomas are characterized by polymerase-ε-(POLE) exonuclease-domain-mutations, an ultra-mutated-phenotype and a favorable prognosis. It is currently unknown whether POLE ultra-mutated-tumors are more immunogenic when compared to the other groups of endometrial cancers.

METHODS

We used autologous-dendritic-cells (DC) pulsed with whole-tumor-extracts to assess the level of CD8+ and CD4+ T-cell-activation induced by POLE-ultramutated (+) and POLE wild-type (-) endometrial cancer cells in vitro. T-lymphocyte-proliferations were evaluated using CFSE and/or ([3H])thymidine-incorporation-assays while the ability to specifically kill autologous-tumor-cells by cytotoxic-T-lymphocyte (CTL) was tested in standard 4-h-(51)Cr-cytotoxicity-assays. In order to correlate cytotoxic activity and proliferation by CD4+ and CD8+ T-lymphocytes, respectively, with a particular lymphoid subset, two-color-flow-cytometric analysis of intracellular-cytokine-expression (IFN-γ vs IL-4) at the single cell level was also performed.

RESULTS

DC-pulsed with tumor extracts were able to induce CTL-responses against autologous-tumor-cells in both POLE (+) and POLE (-) cancer patients (P=0.305). These CD8+ T-cell-populations were cytotoxic against tumor-cells but they did not lyse PHA-stimulated-autologous-lymphocytes or autologous-EBV-transformed-lymphoblastoid-control-cell-lines. In contrast, only POLE (+) tumor-lysate-pulsed-DC were able to induce significant proliferation and high IFN-γ expression (i.e., Th1-cytokine-bias) in autologous in vitro DC-stimulated CD4+ T-cells as well as naïve CD4+ and CD8+ T-cells from patients-peripheral-blood (P<0.05).

CONCLUSIONS

POLE ultra-mutated-tumors are significantly more immunogenic when compared to POLE (-) tumors, in particular to the helper arm of the immune system. These data lend support to the hypothesis that the better prognosis of patients with POLE (+) tumors may at least in part be linked to their enhanced immunogenicity.

Characterization of blood monocyte phenotype in patients with endometrial cancer

BACKGROUND

Endometrial tumors induce various tumor escape mechanisms that result in immunosuppression in patients and, ultimately, tumor progression. Blood monocytes are able to exhibit potent cytotoxic action against tumor cells where novel immunotherapeutics targeting antigen-presenting cells including dendritic cells, and blood monocytes are being used as a means of delivering immunogens to stimulate an antitumor and, ultimately, therapeutic response. This study shows that peripheral blood monocytes from patients with endometrial cancer show functional deficiencies, and these deficiencies can be characterized by phenotypic changes as well as altered cytokine secretion.

METHODS

This study assessed the phenotypic changes of peripheral blood monocytes by flow cytometry as well as the functional status via cytokine production measured by enzyme-linked immunosorbent assay in patients with endometrial cancer versus controls.

RESULTS

Altered blood monocyte phenotype incorporating a decrease in costimulatory and adhesion factor expression and increased expression of vascular endothelial growth factor receptor 1 in patients with endometrial cancer versus controls. Increased interleukin 12 and decreased interleukin 10 secretion by blood monocytes in patients with endometrial cancer were also observed.

CONCLUSIONS

These findings showed that peripheral blood monocytes from patients with endometrial cancer show an altered phenotype and cytokine secretion when compared with controls. Limitations to this study include the small sample size, the need to investigate the effect of phenotype and cytokine changes in functional assays, as well as future studies investigating the effect on tumor-associated macrophages from endometrial tissue from cancer versus control patients. Nevertheless, these findings suggest that peripheral blood monocyte induced immunosuppression in endometrial cancer and implications in the design of future immunotargeting therapies remain to be elucidated.

Immunomodulation in endometrial cancer

Endometrial cancer is the most frequent gynecological cancer and the fourth most common cancer in women in the developed world. Over the last decade, immunotherapy has been the focus of intense investigation as a form of cancer treatment whereby the treatment initiates a host immune response ultimately eradicating the tumor. It has been suggested that in endometrial cancer and many other forms of cancer, immunosuppression poses a significant obstacle at inducing antitumor immunity by immunotherapy. This review will look at the different studies that have identified immunomodulation of T cells, cytokines and macrophages, and regulation of apoptotic and angiogenic factors in endometrial cancer patients that may contribute to the inefficiency of immunotherapy.

Development and characterization of a human single-chain antibody fragment against claudin-3: a novel therapeutic target in ovarian and uterine carcinomas

OBJECTIVE

The purpose of this study was to develop and characterize a human antibody in a single-chain antibody fragment format (scFv) that is directed specifically against claudin-3 (CLDN3).

STUDY DESIGN

The synthetic ETH-2 Gold human antibody phage display library was used to select scFv specific against CLDN3. scFv binding properties were analyzed by surface plasmon resonance; specificity was confirmed with enzyme-linked immunosorbent assay, immunofluorescence, and flow cytometry on a panel of ovarian and uterine serous carcinoma cell lines.

RESULTS

Surface plasmon resonance studies indicated scFv H6 to be the clone with the highest affinity against CLDN3 (K(D) of 23.60 nmol/L). scFv H6 efficiently stained CLDN3-expressing cells and recognized its epitope in enzyme-linked immunosorbent assay that was performed with uterine serous papillary carcinoma native protein extract, which suggested that a conformational epitope is recognized by this antibody. Cell surface immunofluorescence with laser scanning confocal microscopy confirmed the specific binding to the native membrane CLDN3.

CONCLUSION

scFv H6 may represent a novel antitumor agent against chemotherapy-resistant ovarian and serous papillary carcinomas and other human malignancies that overexpress CLDN3.

Presence of tumor-infiltrating lymphocytes is an independent prognostic factor in type I and II endometrial cancer

OBJECTIVE

Presence of tumor-infiltrating lymphocytes (TIL) is of prognostic importance in a variety of malignancies. This study aims to determine the prognostic value of CD8(+) cytotoxic T-lymphocytes (CTL), FoxP3(+) regulatory T-lymphocytes (Treg) and CD45R0(+) memory T-lymphocytes in endometrial cancer.

METHODS

The number of tumor-infiltrating CD8(+), FoxP3(+), and CD45R0(+) T-lymphocytes was determined by immunohistochemistry on tissue microarrays containing tumor material from 368 FIGO stage I-IV endometrial cancer patients. Results from immunohistochemistry were correlated with clinicopathological parameters and survival.

RESULTS

High numbers of intra-tumoral CD8(+) T-lymphocytes, a high CD8(+)/FoxP3(+) ratio and the presence of CD45R0(+) T-lymphocytes were strongly associated with well-known favorable prognostic factors in endometrial cancer. Furthermore, high numbers of CD8(+) T-lymphocytes and a high CD8(+)/FoxP3(+) ratio were associated with a better disease free survival (DFS). High numbers of CD8(+) T-lymphocytes and the presence of CD45R0(+) T-lymphocytes were associated with a prolonged overall survival (OS). In multivariate analysis, high numbers of CD8(+) T-lymphocytes had an independent prognostic impact for overall survival in the entire cohort (HR 0.48, 95% C.I. 0.26-0.89, p=0.019) and in type II endometrial cancer (HR 0.17, 95% C.I. 0.08-0.36, p<0.001). A high CD8(+)/FoxP3(+) ratio was independently associated with improved survival in type I endometrial cancer (HR 0.44, 95% C.I. 0.23-0.84, p=0.013). CD45R0(+) lymphocytes were an independent factor for improved OS (HR 0.42, 95% C.I. 0.19-0.93, p=0.033).

CONCLUSION

This study shows that the presence of TIL is an independent prognostic factor in endometrial cancer and indicates an important role for the immune system in endometrial cancer.

Adoptive transfer of pTRP2-specific CTLs expanding by bead-based artificial antigen-presenting cells mediates anti-melanoma response

Cytotoxic CD8(+) T cells are key effectors in the immunotherapy of malignant and viral diseases. However, the lack of efficient methods for their in vitro priming and expansion has become a bottleneck to the development of vaccines and adoptive transfer strategies. Synthetic artificial antigen-presenting cells (aAPCs) are now emerging as an attractive tool for eliciting and expanding CTL responses. This study reported a novel approach for targeting malignant melanoma with pTRP2-specific cytotoxic T lymphocytes (CTLs) expanded from the C57BL/6 splenocytes by multiple stimulations with aAPCs made by coating H-2K(b)-Ig/pTRP2 dimeric complexes, anti-CD28 antibody, 4-1BBL molecules and CD83 molecules to cell-sized latex beads. The induced CTLs exhibited specific lysis against RMA-S cells pulsed with the peptide pTRP2 and H-2K(b+) melanoma cells expressing TRP2, while a murine Lewis lung carcinoma cell line 3LL could not be recognized by the CTLs. The peptide-specific activity was inhibited by anti-H-2K(b) monoclonal antibody Y3. Adoptive Transfer of CTLs specific for malignant melanoma expanding by the aAPCs can mediate effective anti-melanoma response. These results suggested the bead-based aAPCs coated with an MHC-Ig/peptide complex, anti-CD28 antibody, 4-1BBL and CD83 could provide a useful tool for the reproducible expansion of specific CTLs for adoptive immunotherapy.

Combinational adenovirus-mediated gene therapy and dendritic cell vaccine in combating well-established tumors

Recent developments in tumor immunology and biotechnology have made cancer gene therapy and immunotherapy feasible. The current efforts for cancer gene therapy mainly focus on using immunogenes, chemogenes and tumor suppressor genes. Central to all these therapies is the development of efficient vectors for gene therapy. By far, adenovirus (AdV)-mediated gene therapy is one of the most promising approaches, as has confirmed by studies relating to animal tumor models and clinical trials. Dendritic cells (DCs) are highly efficient, specialized antigen-presenting cells, and DC-based tumor vaccines are regarded as having much potential in cancer immunotherapy. Vaccination with DCs pulsed with tumor peptides, lysates, or RNA, or loaded with apoptotic/necrotic tumor cells, or engineered to express certain cytokines or chemokines could induce significant antitumor cytotoxic T lymphocyte (CTL) responses and antitumor immunity. Although both AdV-mediated gene therapy and DC vaccine can both stimulate antitumor immune responses, their therapeutic efficiency has been limited to generation of prophylactic antitumor immunity against re-challenge with the parental tumor cells or to growth inhibition of small tumors. However, this approach has been unsuccessful in combating well-established tumors in animal models. Therefore, a major strategic goal of current cancer immunotherapy has become the development of novel therapeutic strategies that can combat well-established tumors, thus resembling real clinical practice since a good proportion of cancer patients generally present with significant disease. In this paper, we review the recent progress in AdV-mediated cancer gene therapy and DC-based cancer vaccines, and discuss combined immunotherapy including gene therapy and DC vaccines. We underscore the fact that combined therapy may have some advantages in combating well-established tumors vis-a-vis either modality administered as a monotherapy.

Combination therapy with tumor-lysate pulsed dendritic cells and antiangiogenic drug TNP-470 for mouse pancreatic cancer

Most cases of pancreatic cancer are inoperable when diagnosed. Since immunotherapy and antiangiogenic therapy have been reported to be promising for pancreatic cancer, we examined whether the combination of immunotherapy with dendritic cells (DCs) and the antiangiogenic drug TNP-470 induces tumor regression. Syngeneic mouse pancreatic adenocarcinoma cells were orthotopically inoculated into C57/BL6 mice. DCs with or without tumor lysate (TL) were administered i.p. at 4 and 5 weeks. TNP-470 was injected s.c. into tumor-bearing mice every other day from 4 weeks to 6 weeks. We compared anticancer effects in 6 groups: NT (no treatment), DC/TL- (DCs without TL), DC/TL+ (DCs pulsed with TL), TNP (TNP-470 alone), DC/TL-TNP (DC/TL- plus TNP-470) and DC/TL+TNP (DC/TL+ plus TNP-470). We measured tumor volume, mean vascular density (MVD) and vessel diameter by FITC-dextran using an intravital microscope; degrees of proliferation and apoptosis of cancer cells by PCNA and TUNEL; infiltrating lymphocytes and expression levels of VEGF and MMP-9 by immunohistochemistry and immunoblotting. Tumor volume and MVD were significantly suppressed in the treatment groups with prolonged survival rate, especially in the DC/TL+TNP group. There were no significant differences in apoptosis among the 6 groups except DC/TL+. The number of infiltrating CD4+ cells in the DC/TL+ group was higher than that in the NT group. VEGF expression was significantly suppressed in the treatment groups containing TNP-470, and MMP-9 was also suppressed in the groups containing DC/TL+. Our data suggested that TL-pulsed DCs combined with TNP-470 induced regression of mouse pancreatic cancer, possibly through induction of immune responses and suppression of angiogenesis.

Human kallikrein 6: a new potential serum biomarker for uterine serous papillary cancer

PURPOSE

The discovery of novel biomarkers might greatly contribute to improve clinical management and outcomes in uterine serous papillary carcinoma (USPC), a highly aggressive variant of endometrial cancer.

EXPERIMENTAL DESIGN

Human kallikrein 6 (hK6) gene expression levels were evaluated in 29 snap-frozen endometrial biopsies, including 13 USPC, 13 endometrioid carcinomas, and 3 normal endometrial cells by real-time PCR. Secretion of hK6 protein by 14 tumor cultures, including 3 USPC, 3 endometrioid carcinoma, 5 ovarian serous papillary carcinoma, and 3 cervical cancers, was measured using a sensitive ELISA. Finally, hK6 concentration in 79 serum and plasma samples from 22 healthy women, 20 women with benign diseases, 20 women with endometrioid carcinoma, and 17 USPC patients was studied.

RESULTS

hK6 gene expression levels were significantly higher in USPC when compared with endometrioid carcinoma (mean copy number by real-time PCR, 1,927 versus 239, USPC versus endometrioid carcinoma; P < 0.01). In vitro hK6 secretion was detected in all primary USPC cell lines tested (mean, 11.5 microg/L) and the secretion levels were similar to those found in primary ovarian serous papillary carcinoma cultures (mean, 9.6 microg/L). In contrast, no hK6 secretion was detectable in primary endometrioid carcinoma and cervical cancer cultures. hK6 serum and plasma concentrations (mean +/- SE) among normal healthy females (2.7 +/- 0.2 microg/L), patients with benign diseases (2.4 +/- 0.2 microg/L), and patients with endometrioid carcinoma (2.6 +/- 0.2 microg/L) were not significantly different. In contrast, serum and plasma hK6 values in USPC patients (6.1 +/- 1.1) were significantly higher than those in the noncancer group (P = 0.006), benign group (P = 0.003), and endometrioid carcinoma patients (P = 0.005).

CONCLUSIONS

hK6 is highly expressed in USPC and is released in the plasma and serum of USPC patients. hK6 may represent a novel biomarker for USPC for monitoring early disease recurrence and response to therapy.

High serum levels of interleukin-6 in endometrial carcinoma are associated with uterine serous papillary histology, a highly aggressive and chemotherapy-resistant variant of endometrial cancer

PURPOSE

To evaluate and compare autocrine expression and production of interleukin-6 (IL-6), a pleiotropic cytokine involved in the resistance to cytotoxic agents and inhibition of anti-tumor immune function in endometrial carcinoma in vitro as well as in vivo.

PATIENTS AND METHODS

IL-6 gene expression levels were evaluated in twenty-four primary endometrial tumors including 14 endometrioid carcinomas (EC) and 10 uterine serous papillary carcinoma (USPC) as well as in normal control endometrial cells (NEC) by real-time PCR. Secretion of IL-6 protein by 6 primary endometrial tumor cultures including USPC and EC was measured using a sensitive enzyme-linked immunosorbent assay (ELISA) in vitro. Finally, IL-6 concentration in 71 serum samples including 20 apparently healthy women, 19 women with benign abdominal diseases, 19 women with primary EC, and 13 USPC patients was studied.

RESULTS

IL-6 gene expression levels were significantly higher in USPC when compared to EC (mean copy number by RT-PCR = 313 +/- 55 vs. 53 +/- 11, USPC vs. EC, respectively: P < 0.01). IL-6 serum concentrations between normal healthy females (range 0.01-21.23 pg/ml; mean 3.1 pg/ml) and benign disease patients (range 0.01-95.77 pg/ml; mean 13.07 pg/ml) were not statistically different. In contrast, significantly higher levels of IL-6 were detected in both patients with EC (range 2.86-82.13 pg/ml; mean 20.43 pg/ml) and patients with UPSC (range 16.3-500.1 pg/ml; mean 125.7 pg/ml) when compared to the healthy females (P < 0.01), with a mean serum IL-6 level in USPC patients 6.1-fold higher when compared to EC patients (P < 0.03). Accordingly, higher levels of IL-6 secretion were noted in primary USPC cell lines (mean 3121 pg/ml, range between 1099 and 5017 pg/ml/10(5) cells/48 h) when compared to primary EC (mean 88, range between 19 and 112 pg/ml/10(5) cells/48 h) (P < 0.01) in vitro.

CONCLUSIONS

IL-6 is highly expressed in USPC, and it is released in high concentration in the serum of USPC patients. IL-6 may be a novel biomarker for USPC. Drugs used to inhibit the expression of IL-6 or the IL-6 signal transduction pathway may potentially be highly beneficial in USPC.

Definition of an Immunogenic Region Within the Ovarian Tumor Antigen Stratum Corneum Chymotryptic Enzyme

PURPOSE

The serine protease stratum corneum chymotryptic enzyme (SCCE) is overexpressed by ovarian tumor cells, but is not expressed by normal tissues, suggesting that SCCE may be an attractive target for immunotherapy. In this study, we tested the hypothesis that dendritic cells loaded with SCCE peptides will induce ovarian tumor antigen-specific CD8+ CTL responses and antigen-specific CD4+ helper T cell responses.

EXPERIMENTAL DESIGN

Computer algorithms were used to identify candidate HLA-A2.1-restricted CD8+ CTL epitopes and HLA-DR-binding CD4+ helper T cell epitopes within SCCE. CD8+ CTL stimulated with peptide-loaded dendritic cells were tested against targets expressing endogenous SCCE, including HLA-A2.1-matched ovarian tumor cells. Dendritic cells were also loaded with an extended SCCE peptide, SCCE 110-139, which encompassed a defined CD8+ CTL epitope and multiple candidate CD4+ T helper cell epitopes.

RESULTS

CD8+ CTL specific for SCCE 123-131 lysed autologous macrophages infected with an SCCE-expressing recombinant adenovirus, and also lysed HLA-A2.1-matched, SCCE-expressing ovarian tumor cells. Dendritic cells loaded with SCCE 5-13 peptide stimulated an HLA-A2.1-restricted CD8+ CTL response, but with a reduced level of lysis against ovarian tumor cells. Dendritic cells loaded with SCCE 110-139 induced antigen-specific CD4+ T cell and CD8+ T cell responses. Although SCCE 110-139-loaded dendritic cells processed and presented the 123-131 epitope, the dominant CD8+ CTL response was directed against alternative epitopes within SCCE 110-139.

CONCLUSIONS

The 110-139 region of SCCE incorporates multiple CD8+ CTL and CD4+ helper T cell epitopes, and represents an attractive target antigen for immunotherapy of ovarian cancer.

Dendritic cells induce immunity and long-lasting protection against blood-stage malaria despite an in vitro parasite-induced maturation defect

Dendritic cells (DC) suffer a maturation defect following interaction with erythrocytes infected with malaria parasites and become unable to induce protective malaria liver-stage immunity. Here we show that, by contrast, maturation-arrested DC in vitro are capable of the successful induction of antigen-specific gamma interferon (IFN-gamma) and interleukin 4 (IL-4) T-cell responses, antibody responses, and potent protection against lethal blood-stage malaria challenge in vivo. Similar results were found with DC pulsed with intact parasitized Plasmodium yoelii or Plasmodium chabaudi erythrocytes. Cross-strain protection was also induced. High levels of protection (80 to 100%) against lethal challenge were evident from 10 days after a single immunization and maintained up to 120 days. Interestingly, correlation studies versus blood-stage protection at different time points suggest that the immune effector mechanisms associated with protection could change over time. Antibody-independent, T-cell- and IL-12-associated protection was observed early after immunization, followed by antibody and IL-4-associated, IFN-gamma-independent protection in long-term studies. These results indicate that DC, even when clearly susceptible to parasite-induced maturation defect effects in vitro, can be central to the induction of protection against blood-stage malaria in vivo.

Discrimination between uterine serous papillary carcinomas and ovarian serous papillary tumours by gene expression profiling

High-grade ovarian serous papillary cancer (OSPC) and uterine serous papillary carcinoma (USPC) represent two histologically similar malignancies characterised by markedly different biological behavior and response to chemotherapy. Understanding the molecular basis of these differences may significantly refine differential diagnosis and management, and may lead to the development of novel, more specific and more effective treatment modalities for OSPC and USPC. We used an oligonucleotide microarray with probe sets complementary to >10 000 human genes to determine whether patterns of gene expression may differentiate OSPC from USPC. Hierarchical cluster analysis of gene expression in OSPC and USPC identified 116 genes that exhibited >two-fold differences (P<0.05) and that readily distinguished OSPC from USPC. Plasminogen activator inhibitor (PAI-2) was the most highly overexpressed gene in OSPC when compared to USPC, while c-erbB2 was the most strikingly overexpressed gene in USPC when compared to OSPC. Overexpression of the c-erbB2 gene and its expression product (i.e., HER-2/neu receptor) was validated by quantitative RT-PCR as well as by flow cytometry on primary USPC and OSPC, respectively. Immunohistochemical staining of serous tumour samples from which primary OSPC and USPC cultures were derived as well as from an independent set of 20 clinical tissue samples (i.e., 10 OSPC and 10 USPC) further confirmed HER-2/neu as a novel molecular diagnostic and therapeutic marker for USPC. Gene expression fingerprints have the potential to predict the anatomical site of tumour origin and readily identify the biologically more aggressive USPC from OSPC. A therapeutic strategy targeting HER-2/neu may be beneficial in patients harbouring chemotherapy-resistant USPC.

Increased levels of gangliosides in the plasma and ascitic fluid of patients with advanced ovarian cancer

OBJECTIVES

To assess the expression of total gangliosides in primary ovarian cancer cell lines, ascitic fluid and plasma of advanced ovarian cancer patients.

DESIGN

A prospective study.

SETTING

The Department of Obstetrics and Gynecology at the University of Arkansas for Medical Sciences and the Laboratory of Glycolipid Immunotherapy, John Wayne Cancer Institute.

POPULATION

Twenty-two women diagnosed with advanced ovarian cancer and seven normal female controls.

METHODS

Total gangliosides shedding from primary ovarian cancer cell lines were measured by estimating lipid-associated sialic acids (LASAs test) and compared with the ganglioside levels shed by primary cervical and uterine cancer cell lines. In addition, plasma and ascitic samples from advanced ovarian cancer patients were collected at the time of surgery and analysed for the presence of total gangliosides.

MAIN OUTCOME MEASURES

Levels of total ganglioside in plasma and ascites fluid samples drawn from ovarian cancer patients, relative to total gangliosides levels in plasma from normal female controls.

RESULTS

All primary ovarian tumours secreted high levels of total gangliosides (mean 4 mg/mL, range between 2.7 and 4.8 mg/mL/10(5) cells/24 h) when compared with primary cervical cancers (mean 1.4 mg/mL, range between 0.7 and 2.2 mg/mL/10(5) cells/24 h) (P < 0.008) and uterine carcinoma cell lines (mean 1.4 mg/mL, range between 1.3 and 1.6 mg/mL/10(5) cells/24 h) (P <.004). Elevated levels of total gangliosides were detected in the plasma [mean (SD) 31 (12) mg/mL, range between 18 and 57 mg/mL] (P <.001), and in the peritoneal fluid [mean (SD) 27 (9) mg/mL, range between 14 and 40 mg/mL] (P <.003) of ovarian cancer patients when compared with the levels detectable in the plasma samples of normal female controls tested [mean (SD) 15 (2) mg/mL, range between 12 and 18 mg/mL].

CONCLUSIONS

Increased serum levels of total gangliosides may reflect shedding or release of gangliosides from the surface of ovarian tumour cells. Secretion of gangliosides may play an important role in the inhibition of anti-tumour immune function commonly observed in advanced ovarian cancer.

Disease-associated dendritic cells respond to disease-specific antigens through the common heat shock protein receptor

The most abundant intracellular proteins, heat shock proteins (HSPs), serve as molecular chaperones for regulatory and maturation pathways. Diverse families of HSPs have been shown to bind antigenic peptides and to play major roles in innate and adaptive immune responses through the common HSP receptor, CD91. HIV-1+ patients with Kaposi sarcoma (KS) were matched for CD4 count and HIV-1 RNA viral load to HIV-1+ patients without Kaposi sarcoma (and negative for Kaposisarcoma-associated herpesvirus). We then investigated the pathways used by tumor lysates, viral lysates, and viral particles in their activation. In particular, we observed immune responses after HSP depletion using antitumor antibiotics and blockade of the common HSP receptor, CD91. Despite the impaired functional capacity of dendritic cells (DCs) derived from patients with KS, DCs retain the ability to prime the adaptive arm of the immune system through the common HSP receptor, leading to phenotypic activation and stimulation of tetramer-positive CD8+ cytotoxic T cells. We also show that interferon-producing plasmacytoid DCs are selectively depleted in KS-positive compared with matched KS-negative HIV-1-infected patients. Functionally impaired DCs can effectively cross-present immune responses through the common HSP receptor. These results have important implications for the etiopathogenesis of KS and for the development and design of any compounds, including vaccines, derived from cellular lysates.

Dendritic cell-based immunotherapy

Dendritic cell (DC)-based vaccinations represent a promising approach for the immunotherapy of cancer and infectious diseases as DCs play an essential role in initiating cellular immune responses. A number of clinical trials using ex vivo-generated DCs have been performed so far and only minor toxicity has been reported. Both the induction of antigen-specific T cells and clinical responses have been observed in vaccinated cancer patients. Nevertheless, DC-based immunotherapy is still in its infancy and there are many issues to be addressed such as antigen loading procedures, DC source and maturational state, migration properties, route, frequency, and dosage of DC vaccination. The increasing knowledge of DC biology should be used to improve the efficacy of this new therapy.

Advances in dendritic cell-based vaccine of cancer

Dendritic cells (DCs) are potent antigen presenting cells that exist in virtually every tissue, and from which they capture antigens and migrate to secondary lymphoid organs where they activate naïve T cells. Although DCs are normally present in extremely small numbers in the circulation, recent advances in DC biology have allowed the development of methods to generate large numbers of these cells in vitro. Because of their immunoregulatory capacity, vaccination with tumor antigen-presenting DCs has been proposed as a treatment modality for cancer. In animal models, vaccination with DCs pulsed with tumor peptides, lysates, or RNA or loaded with apoptotic/necrotic tumor cells could induce significant antitumor CTL responses and antitumor immunity. However, the results from early clinical trails pointed to a need for additional improvement of DC-based vaccines before they could be considered as practical alternatives to the existing cancer treatment strategies. In this regard, subsequent studies have shown that DCs that express transgenes encoding tumor antigens are more potent primers of antitumor immunity both in vitro and in vivo than DCs simply pulsed with tumor peptides. Furthermore, DCs that have been engineered to express certain cytokines or chemokines can display a substantially improved maturation status, capacity to migrate to secondary lymphoid organs in vivo, and abilities to stimulate tumor-specific T cell responses and induce tumor immunity in vivo. In this review we also discuss a number of factors that are important considerations in designing DC vaccine strategies, including (i) the type and concentrations of tumor peptides used for pulsing DCs; (ii) the timing and intervals for DC vaccination/boostable data on DC vaccination portends bright prospects for this approach to tumor immune therapy, either alone or in conjunction with other therapies.

Leukemic dendritic cells: potential for therapy and insights towards immune escape by leukemic blasts

Dendritic cells (DCs) are a system of potent antigen-presenting cells (APCs) specialized to initiate primary immune responses. DCs are considered important elements in the induction of specific antitumor cytotoxic effectors. At present, because of potential therapeutic implications, the critical role of DCs in cancer patients is under intensive investigation. Interactions between DCs and acute myeloid leukemia cells represent an attractive model for the study of DC physiology. Moreover, DCs can be a valuable therapeutic tool for the adjuvant treatment of leukemic patients. However, DC subsets in vivo may also be affected by leukemogenesis and may contribute to the escape of leukemia from immune control. The aim of this review is to shed further light on this paradoxical picture where the line between immune tolerance and immune defense is narrow.