DNAX accessory molecule-1 (CD226) promotes human hepatocellular carcinoma cell lysis by Vgamma9Vdelta2 T cells.

Human Vgamma9Vdelta2 T lymphocytes can be activated by nonpeptidic antigens such as the mevalonate pathway-derived isopentenyl pyrophosphate or synthetic phosphoantigen such as bromohydrin pyrophosphate. They display a strong cytotoxic activity against several tumor types, including hepatocellular carcinoma (HCC). Little is known about the mechanisms underlying Vgamma9Vdelta2 T-cell recognition of tumor cells, but there is strong evidence that activating NK receptors play a role in gammadelta T-cell cytotoxicity. In this study, we showed that the two NK receptors DNAX accessory molecule-1 (DNAM-1) and CD96 were expressed by Vgamma9Vdelta2 T cells. The ligands Nectin-like-5 specific of both DNAM-1 and CD96, and also Nectin-2, an additional ligand of DNAM-1, were present on all HCC cell lines analyzed. Furthermore, we demonstrated by mAb-mediated masking experiments that cytotoxicity against HCC cells as well as IFN-gamma production in gammadelta T cells were dependent on DNAM-1. Our experiments indicated that Nectin-like-5 but not Nectin-2 was involved in DNAM-1-dependent gammadelta T-cell functions. We did not reveal a role for CD96 in the killing of HCC cells. Finally, we showed by combined mAb-mediated blockade that DNAM-1 and NKG2D could cooperate in the cell lysis of HCC.

The prognostic value of erythrocyte polyamine in the post-nephrectomy stratification of renal cell carcinoma specific mortality.

PURPOSE: The polyamines spermine and spermidine are ubiquitous polycationic structures which are essential for cell proliferation and differentiation. Circulating polyamines, spermine and spermidine, represent valuable prognostic markers in prostate cancer, acute leukemia and supratentorial malignant glioma. We tested whether spermine and spermidine could improve the prognostic ability of several established predictors of cancer specific mortality after partial or radical nephrectomy for renal cell carcinoma. MATERIALS AND METHODS: Testing was performed on 399 patients with stages T(1-4), N(0-2), M(0-1) renal cell carcinoma who were treated with radical or partial nephrectomy at a single institution between 1990 and 2007. Univariable and multivariable Cox regression models tested the prognostic ability of spermine and spermidine levels in cancer specific mortality predictions. Covariates consisted of TNM stage, Fuhrman grade, tumor size and symptom classification. Harrell's concordance index (c-index) quantified accuracy and 200 bootstrap resamples were used to correct for overfit bias. RESULTS: The 5-year cancer specific mortality-free survival of patients with spermine levels 3 or less, 3.1 to 8, 8.1 to 13 and greater than 13 nmol/8x10(9) erythrocytes was 88.8%, 75.8%, 40.2% and 21.8%, respectively. Similarly the 5-year cancer specific mortality-free survival of patients with spermidine levels 12 or less, 12.1 to 15, 15.1 to 21 and greater than 21 nmol/8x10(9) erythrocytes was 79.0%, 56.6%, 53.2% and 27.4%, respectively. On multivariable analyses addressing cancer specific mortality after surgery spermine (p = 0.007) and spermidine (p = 0.04) achieved independent predictor status. Consideration of spermine and spermidine also improved the accuracy of established cancer specific mortality predictors by 2.2% (p <0.001). CONCLUSIONS: Spermine and spermidine may significantly improve the prognostic value of established cancer specific mortality predictors after partial or radical nephrectomy for all stages of renal cell carcinoma. Independent external validation of our findings is required.

[Tgammadelta lymphocytes in oncology: unconventional killer lymphocytes]. / Lymphocytes Tgd en cancérologie: des lymphocytes tueurs non conventionnels.

Gamma delta T cells are a distinct subset of CD3+ T cells featuring both T cells receptors that are encoded by Vgamma- and Vdelta- gene segments and characteristics of innate immunity. In human blood, 80% of those express Vgamma9Vdelta2-TCRs that are specific for conserved non peptidic compound, phosphoantigens (PAgs). Vgamma9Vdelta2 T cells recognize in vitro a wide array of transformed cells and are activated in vivo in various tumor. Owing to their ability to directly kill tumor cells and produce inflammatory cytokines (such as IFN-gamma) boosting antitumor properties of other immune effector cells, gamma delta T cells contribute to protective immunity against cancers. These observations, and the recent availability of synthetic clinical grade PAg or pharmacological inducers of PAg (e.g. aminobisphosphonates) able to trigger Vgamma9Vdelta2 T cell, have fostered development of new gammadelta T cell-based therapeutic strategies, which are depicted in this review.

Activation of tumor-specific T cells by dendritic cells expressing the NY-ESO-1 antigen after transfection with the cationic lipophosphoramide KLN5.

BACKGROUND: Genetic modification of human monocyte-derived dendritic cells (DC) with cDNA sequences encoding tumor-associated antigens (TAA) is a promising strategy for cancer immunotherapy. The present study aimed to develop a nonviral gene transfer method based on the use of the cationic lipophosphoramide reagent, KLN-5, as an alternative to the commonly used viral vectors. METHODS: First, the efficiency of KLN5 for gene transfection into DC was investigated using the green fluorescent protein (GFP) reporter gene. The highest transfection efficiency/cell viability ratio was determined by flow cytometry. Next, DC were transfected with a plasmid encoding NY-ESO-1, a TAA expressed in numerous cancers, according to the transfection protocol previously established with the GFP reporter. Transfected DC were then co-cultured with a CD8+ NY-ESO-1 specific HLA-A*02.01 T cell clone to control their ability to correctly process and present the corresponding epitope in the HLA-A*02.01 context. Finally, T cell activation was assessed via flow cytometry-based detection of interferon-gamma production. RESULTS: An optimal KLN5/plasmid DNA ratio allowing both significant transgene expression and high viability of DC could be determined. Under the established experimental conditions, antigen processing and presentation of the immunodominant (SLLMWITQC(157-165)) epitope in the HLA-A*0201 context was demonstrated by activation of the NY-ESO-1-specific CD8+ T cell clone. CONCLUSIONS: KLN5-based gene transfection into DC allows the efficient induction of TAA presentation and may thus represent a novel attractive nonviral approach for cancer vaccination.

Constitutive expression of TGF-bêta1, interleukin-6 and interleukin-8 by tumor cells as a major component of immune escape in human ovarian carcinoma.

Tumors could use several mechanisms to coexist with the host's immune system or to protect themselves from an immune response. Thus, insufficient expression of cell surface molecules on tumor cells, which are important for T cell recognition or activation, could lead to induction of a state of tolerance. Tumor cells could also produce cytokines that would inhibit the immune response and allow tumor progression. Here, we studied, in vitro, the cell surface expression of immunologically important molecules in seven ovarian carcinoma (OVCA) cell lines and the constitutive expression of cytokines. All OVCA cell lines expressed MHC class I molecules, ICAM-1 and LFA-3 adhesion molecules, necessary to induce a specific cytotoxic T-cell response, as well as the CD40 costimulatory molecules. Conversely, the lack of the dominant costimulatory molecules, CD80 (B7.1) and CD86 (B7.2) could be a possible explanation of poor immunogenicity of OVCA tumors. Immunosuppressive TGF-beta1 was detected at the mRNA level in all cell lines but was weakly secreted in supernatants. By contrast, IL-10 was never found. Most of them constitutively produced IL-8 and IL-6, two cytokines known as tumor promoting factors whereas the proinflammatory cytokines TNF-alpha, IL-1beta and GM-CSF were rarely produced. Data from this study could be useful for designing new strategies of immunotherapy to improve immunogenicity and/or limit protumor cytokine production.

[Antitumor immunity and cellular cancer therapies]. / Immunité anti-tumorale et thérapies cellulaires du cancer.

The identification of tumor specific antigens has provided important advance in tumor immunology. It is now established that specific cytotoxic T lymphocytes (CTL) and natural killer cells infiltrate tumor tissues and are effector cells able to control tumor growth. However, such a natural antitumor immunity has limited effects in cancer patients. Failure of host defenses against tumor is consecutive to several mechanisms which are becoming targets to design new immunotherapeutic approaches. CTL are critical components of the immune response to human tumors and induction of strong CTL responses is the goal of most current vaccine strategies. Effectiveness of cytokine therapy, cancer vaccines and injection of cells improving cellular immunity have been established in tumor grafted murine models. Clinical trials are underway. To day, interest is particularly focused on cell therapy: injected cells are either "ready to use" effector cells (lymphocytes) or antigen presenting cells able to induce a protective immune reaction in vivo (dendritic cells). The challenge ahead lie in the careful optimization of the most promising strategies in clinical situation.

[Local immune tolerance mechanisms in kidney cancer]. / Mécanismes de tolérance immunitaire locale dans les cancers du rein.

Many arguments suggest that renal tumours are immunogenic. However, the immune cells present around or within the tumour are unable to induce tumour rejection and the results of immunotherapy in metastatic renal cancer remain disappointing regardless of the protocols used. The objective of this study was to review the main mechanisms by which a renal tumour can escape immune destruction. These mechanisms can concern: tumour antigens, antigen-presenting molecules on the cell surface or defects of the cell machinery leading to the preparation of these molecules. Defects may also concern intercellular communications, especially adhesion and co-stimulation molecules. The immune cells present may also be defective, presenting qualitative or quantitative deficits, abnormalities of the T receptor, defect of cytokine production and these defects may concern both effector cells and antigen-presenting cells. The capacity of tumour cells to release anergic substances, i.e. substances which paralyze the immune system, also constitutes another very powerful immunosuppressive mechanism. These substances are cytokines, especially TGF-b. This anergy can also be mediated by intercellular contacts between tumour cells and lymphocytes, especially via the Fas system. It is important to study these mechanisms for several reasons: 1/Understanding of anergy mechanisms in order to discover new therapeutic targets or to short-circuit these mechanisms in vitro; 2/Definition of an "immune phenotype" of the tumour which should be evaluated as a prognostic marker both for survival after radical surgery of localized tumours as a prognostic factor for response to immunotherapy in metastatic forms.

The prognostic value of erythrocyte polyamines in the preoperative evaluation of patients with renal cell carcinoma.

INTRODUCTION: Polyamines, spermine and spermidine, are ubiquitous polycationic structures, which are essential for cell proliferation and differentiation. We tested whether spermine and spermidine could improve the prognostic ability of six established preoperative predictors of cancer-specific mortality (CSM) after partial or radical nephrectomy for renal cell carcinoma (RCC). MATERIALS AND METHODS: Overall, 385 patients with clinical stages T(1-3), M(0-1) RCC were treated with radical or partial nephrectomy at a single institution between 1990 and 2007. Kaplan-Meier plots depicted CSM after stratification according to spermine and spermidine levels (dichotomised to above and below the median value). Univariable and multivariable Cox regression models tested the prognostic ability of continuously coded spermine and spermidine levels in preoperative CSM predictions. Covariates consisted of pre-treatment T stage, M stage, age, gender and symptom classification. RESULTS: The 5-year CSM-free survival of patients with spermine levels < or =4.5 and >4.5 nmol/8x10(9) erythrocytes were, respectively, 79.5% and 65.0%. Similarly, the 5-year CSM-free survival of patients with spermidine levels < or =9.0 and >9.0 nmol/8x10(9) erythrocytes were, respectively, 81.1% and 63.7%. In multivariable analyses addressing CSM after surgery, both spermine (p< or =0.002) and spermidine (p< or =0.001) achieved independent predictor status and improved the accuracy of established preoperative CSM predictors by 2.1% (p<0.001). CONCLUSIONS: Circulating polyamine levels may significantly improve the prognostic value of established determinants of CSM in patients with RCC of all stages prior to nephrectomy. External validation of our findings is required prior to implementation in clinical practice.