New gene expressed in prostate: a potential target for T cell-mediated prostate cancer immunotherapy.

New gene expressed in prostate (NGEP) is a prostate-specific gene encoding either a small cytoplasmic protein (NGEP-S) or a larger polytopic membrane protein (NGEP-L). NGEP-L expression is detectable only in prostate cancer, benign prostatic hyperplasia and normal prostate. We have identified an HLA-A2 binding NGEP epitope (designated P703) which was used to generate T cell lines from several patients with localized and metastatic prostate cancer. These T cell lines were able to specifically lyse HLA-A2 and NGEP-expressing human tumor cells. NGEP-P703 tetramer binding assays demonstrated that metastatic prostate cancer patients had a higher frequency of NGEP-specific T cells when compared with healthy donors. Moreover, an increased frequency of NGEP-specific T cells was detected in the peripheral blood mononuclear cells of prostate cancer patients post-vaccination with a PSA-based vaccine, further indicating the immunogenicity of NGEP. These studies thus identify NGEP as a potential target for T cell-mediated immunotherapy of prostate cancer.

Enhanced functionality of CD4+CD25(high)FoxP3+ regulatory T cells in the peripheral blood of patients with prostate cancer.

PURPOSE: CD4+CD25(high)FoxP3+ regulatory T cells (Treg) have been shown to inhibit the activation and function of T cells that participate in antigen-specific immune responses. Higher levels of Tregs have been reported in the peripheral blood of patients with several types of tumors. In this study, we investigated the number and functionality of CD4+CD25(high)FoxP3+ Tregs in patients with prostate cancer (PCa), and their potential role in inhibiting antitumor immune responses. EXPERIMENTAL DESIGN: Levels of Tregs in the peripheral blood of healthy donors and patients with biochemically progressive, localized, and metastatic PCa were each measured by flow cytometry. The functional activity of Tregs was determined by their ability to suppress the proliferation of CD4+CD25- T cells. Data were analyzed using Wilcoxon rank sum test and unpaired Student's t test. RESULTS: Although levels of Tregs in the peripheral blood of patients with PCa were not significantly higher than those in healthy donors, Tregs in patients with PCa had significantly greater suppressive functionality than Tregs from healthy donors (P < 0.05). Additionally, there was a direct correlation between the serum levels of prostaglandin E(2) and Treg functionality in patients with localized PCa, using Pearson's product-moment correlation coefficient (R). CONCLUSIONS: These findings further show the potential importance of Tregs in modifying immune responses in patients with PCa. Although longer studies are necessary to confirm these findings, these studies also show for the first time the differences in Treg populations in patients with various stages of PCa, and thus, provide a basis for determining which PCa patient populations are best suited for immunotherapy trials involving the inhibition of Tregs.

Immunity feedback and clinical outcome in colon cancer patients undergoing chemoimmunotherapy with gemcitabine + FOLFOX followed by subcutaneous granulocyte macrophage colony-stimulating factor and aldesleukin (GOLFIG-1 Trial).

PURPOSE: GOLFIG chemoimmunotherapy regimen proved to be a safe and very active chemoimmunotherapy regimen in advanced colon cancer patients. We have thus investigated the immunobiological feedback to the treatment and its possible correlation with the clinical outcome of these patients. EXPERIMENTAL DESIGN: This clinical and immunologic study involved 46 patients, 27 males and 19 females, enrolled in the GOLFIG-1 phase II trial who received gemcitabine (1,000 mg/m(2) on days 1 and 15), oxaliplatin (85 mg/m(2) on days 2 and 16), levofolinic acid (100 mg/m(2) on days 1, 2, 15, and 16), and 5-fluorouracil (400 mg/m(2) as a bolus, and 800 mg/m(2) as a 24-hour infusion on days 1, 2, 15, and 16) followed by s.c. granulocyte macrophage colony-stimulating factor (100 mug, on days 3-7) and interleukin 2 (0.5 x 10(6) IU twice a day on days 8-14 and 17-29). RESULTS: The regimen was confirmed to be safe and very active in pretreated patients with metastatic colorectal cancer. A subgroup analysis of these patients revealed a prolonged time to progression and survival in six patients who developed late signs of autoimmunity. A multivariate analysis validated the occurrence of autoimmunity signs as an independent predictor of favorable outcome. A parallel immunologic study detected in the peripheral blood mononuclear cells of these patients a progressive increase in lymphocyte and eosinophil counts, amplification in central memory, a marked depletion of immunosuppressive regulatory T cells, and activation of colon cancer-specific cytotoxic T cells. CONCLUSIONS: Our results suggest that immunity feedback to GOLFIG regimen and its antitumor activity are tightly correlated.

Pilot study of vaccination with recombinant CEA-MUC-1-TRICOM poxviral-based vaccines in patients with metastatic carcinoma.

PURPOSE: Poxviral vectors have a proven safety record and can be used to incorporate multiple transgenes. Prior clinical trials with poxviral vaccines have shown that immunologic tolerance to self-antigens can be broken. Carcinoembryonic antigen (CEA) and MUC-1 are overexpressed in a substantial proportion of common solid carcinomas. The primary end point of this study was vaccine safety, with immunologic and clinical responses as secondary end points. EXPERIMENTAL DESIGN: We report here a pilot study of 25 patients treated with a poxviral vaccine regimen consisting of the genes for CEA and MUC-1, along with a triad of costimulatory molecules (TRICOM; composed of B7.1, intercellular adhesion molecule 1, and lymphocyte function-associated antigen 3) engineered into vaccinia (PANVAC-V) as a prime vaccination and into fowlpox (PANVAC-F) as a booster vaccination. RESULTS: The vaccine was well tolerated. Apart from injection-site reaction, no grade > or =2 toxicity was seen in more than 2% of the cycles. Immune responses to MUC-1 and/or CEA were seen following vaccination in 9 of 16 patients tested. A patient with clear cell ovarian cancer and symptomatic ascites had a durable (18-month) clinical response radiographically and biochemically, and one breast cancer patient had a confirmed decrease of >20% in the size of large liver metastasis. CONCLUSIONS: This vaccine strategy seems to be safe, is associated with both CD8 and CD4 immune responses, and has shown evidence of clinical activity. Further trials with this agent, either alone or in combination with immunopotentiating and other therapeutic agents, are warranted.

Anti-angiogenetic effects of immune-reconstituted influenza virosomes assembled with parathyroid hormone-related protein derived peptide vaccine.

BACKGROUND: C-IRIV/PTR-4 is a novel anticancer vaccine construct composed of immune-reconstituted influenza virosomes (IRIV) assembled with the PTH-rP derived peptide (PTR)-4, a synthetic CTL epitope with HLA-A(*)02.01 amino acid binding motifs. This peptide is able to generate a human PTH-rP specific CTL response with anti-tumor activity in vitro and in mice. MATERIALS AND METHODS: We have investigated the immunological and preventive anti-tumor activity of C-IRIV/PTR-4 compared with the soluble PTR-4 peptide, in HHD mice inoculated with autologous PTH-rP+ tumor cells. RESULTS: Peptide vaccination with either a soluble and an IRIV formulation showed similar immunological activity and the ability to purge the tumor tissue of tumor cell clones able to produce the target antigen (PTR-rP). The most efficient protection from tumor growth was however observed in animals vaccinated with C-IRIV/PTR-4 in which an additional IRIV related anti-angiogenetic effect was detected in the tumor tissue. CONCLUSIONS: These results confirm the immunological activity of PTR-4 vaccination and suggest a more efficacious therapeutic potential of C-IRIV/PTR-4 against bone metastases and malignancies like breast, prostate and lung which very often over-express PTH-rP.

Dose/dense metronomic chemotherapy with fractioned cisplatin and oral daily etoposide enhances the anti-angiogenic effects of bevacizumab and has strong antitumor activity in advanced non-small-cell-lung cancer patients.

BACKGROUND: We designed a translational clinical trial to investigate whether a dose/dense chemotherapy regimen is able to enhance in patients with non-small-cell-lung-cancer (NSCLC) the anti-angiogenic effects of bevacizumab, a murine/human monoclonal antibody to the vasculo-endothelial-growth-factor (VEGF). We also evaluated the antitumor activity of this combination. RESULTS: The combined treatment induced a significant decline in the blood-perfusion of primary tumor (NMR-study); in serum levels of VEGF, angiopoietin-1, thrombospondin-1; and in the number of VEGF-transporting cells. In the group of 40 patients who received bevacizumab an objective response and a disease stabilization rate of 77.5% (95% CI, 75.63-93.17) and 15%, respectively, were recorded with a time to progression of 7.6 mo. Grade I-II hematological toxicity was the most common adverse event. Four early deaths within 3 mo, three cases of pneumonia, and six cases of mood depression at higher bevacizumab dosage were observed. The most active biological and maximum tolerated dose were 5 and 7.5 mg/kg, respectively. PATIENTS AND METHODS: Forty-eight patients (42 males and six females) with stage III B/IV NSCLC, a mean age of 68 y, and ECOG

Cytotoxic drugs up-regulate epidermal growth factor receptor (EGFR) expression in colon cancer cells and enhance their susceptibility to EGFR-targeted antibody-dependent cell-mediated-cytotoxicity (ADCC).

Cetuximab is a human-murine chimeric IgG1 monoclonal antibody to epidermal growth factor-receptor (EGFR) which exerts synergistic antitumour interactions with several cytotoxic drugs. Therefore, it is presently recommended in combination with chemotherapy in the treatment of colon, head and neck and non-small cell lung cancer. Cetuximab has been designed to inhibit EGFR signalling; however, preclinical evidence suggests that its anti-cancer effects in vivo are also related to the ability of its human IgG1 backbone to trigger immunological mechanisms. Here we have investigated whether the exposure to different cytotoxic drugs may affect the susceptibility of colon cancer cells in vitro to cetuximab immuno-targeting and related lymphokine-activated killer (LAK)-mediated antibody-dependent cell cytotoxicity (ADCC). Five colon cancer cell lines expressing a different k-ras mutational status were evaluated for: (i) EGFR-expression, (ii) susceptibility to LAK cells and (iii) cetuximab-mediated ADCC, before and after exposure to 5-flurouracil (5-FU), gemcitabine (Gem), irinotecan (Iri) alone or in multiple two/three drug combinations. These drugs were able to up-regulate EGFR expression on the surface of all the colon cancer cell lines with a maximal effect observed few hours after the exposure to GILF regimen (Gem, Iri, Levofolinic acid and 5-FU). Chemotherapy was able to greatly enhance the sensitivity to either LAK cells or cetuximab-mediated ADCC in all the colon cancer cell lines with a mechanism independent from k-ras status. The results of our study suggest that chemotherapy may enhance cetuximab-mediated immuno-targeting and ADCC thus providing the rationale to design novel immuno-biochemotherapy regimens.

Regulatory (FoxP3+) T-cell tumor infiltration is a favorable prognostic factor in advanced colon cancer patients undergoing chemo or chemoimmunotherapy.

Antitumor immune response and chemotherapy-induced immunomodulation in colon cancer patients represented the rationale to design new strategies, like GOLFIG chemoimmunotherapy (gemcitabine, oxaliplatin, 5-fluorouracil/folinic acid, granulocyte macrophage colony-stimulating factor, and aldesleukine), that resulted a safe and very active regimen. Antitumor activity and immunity feedback to GOLFIG were strictly correlated with the best outcome observed in patients with autoimmunity signs, increase of central memory T cells, and decrease of regulatory T cells (Treg) in the peripheral blood. We thus investigated a potential correlation between the Treg tumor infiltration at diagnosis and the clinical outcome in a current randomized phase 3 trial aimed to compare the GOLFIG regimen with the standard FOLFOX chemotherapy (GOLFIG-2). An immunohistochemistry study was carried out to quantify the infiltration of Treg/FoxP3+ T lymphocytes in tumor samples of 57 patients enrolled in the GOLFIG-2 trial. Treg tumor infiltration scores were correlated with overall survival, treatment-relative survival, and progression-free survival (PFS). Higher Treg tumor infiltration scores were associated with a better prognosis in the whole series (Treg high score vs. low score: overall survival=mean 43.2 mo vs. 28.6 mo, P=0.0005) and a better outcome after treatment (Treg high score vs. low score: PFS=mean 15.8 mo vs. 8.8 mo, P=0.0009; treatment-relative survival=mean 23.1 mo vs. 18.2 mo, P=0.004). PFS was significantly longer in GOLFIG high versus all other subgroups (mean 18.1 mo vs. 9.9 mo, P=0.01). Our results suggest that a higher FoxP3+ T-lymphocyte tumor infiltration score is a favorable prognostic factor in colon cancer patients undergoing chemo or chemoimmunotherapy.

Human dendritic cell maturation and activation by a heat-killed recombinant yeast (Saccharomyces cerevisiae) vector encoding carcinoembryonic antigen.

Tumor-associated antigens are weakly immunogenic. Human carcinoembryonic antigen (CEA) is overexpressed on a wide range of human carcinomas and represents an attractive target for cancer immunotherapy. This study analyzes the ability of a Saccharomyces cerevisiae vector containing the transgene encoding CEA (yeast-CEA) to activate human dendritic cells (DCs) and stimulate CEA-specific T-cell responses. We demonstrate for the first time that treatment with yeast-CEA can activate human DCs, resulting in increases in surface expression of CD80, CD83, CD54, CD58, and MHC class II, and increased production by DCs of IL-12p70, TNF-alpha, IFN-gamma, IL-8, IL-2, IL-13, IL-10, and IL-1beta. We also show that human DCs treated with yeast-CEA can activate CEA-specific T-cell lines and can act as antigen-presenting cells (APCs) to generate CEA-specific T-cell lines capable of lysing CEA(+) human tumor cells. Gene expression profiles of human DCs treated with yeast-CEA show increased expression of numerous genes involved in the production of chemokines and cytokines and their receptors, and genes related to antigen uptake, antigen presentation, and signal transduction.

Second-line treatment of non small cell lung cancer by biweekly gemcitabine and docetaxel +/- granulocyte-macrophage colony stimulating factor and low dose aldesleukine.

Background. The antitumor activity of a novel biweekly gemcitabine (G) + docetaxel (D) regimen +/- granulocyte-macrophage colony stimulating factor (GM-CSF) and aldesleukine (IL-2) has been evaluated in a phase II trial in advanced pretreated non-small-cell lung cancer (NSCLC). Results. The treatment was well tolerated. The 42.3% response rate exceeded the predefined target activity, while time to progression (TTP) and overall survival (OS) were 7 and 11.2 months, respectively. A greater objective response rate (58.3% vs 28.6%) and an increased number of eosinophils, basophils and activated mononuclear blood cells were observed in those patients who also received cytokine administration. Methods. Twenty-six NSCLC patients received second line G (1000 mg/m2) and D (75 mg/m2) every 15 days. 12/26 patients also received s.c. GM-CSF (100µg, days 2-6) and s.c. IL-2 (0.5MIU/ twice daily, days 7-14 and 16-29) by random selection. Conclusion. The biweekly GD regimen is a safe and active second-line treatment in NSCLC. Addition of immune-adjuvant cytokines' may enhance the activity of this therapeutic combination.

Identification of cytotoxic T-lymphocyte epitope(s) and its agonist epitope(s) of a novel target for vaccine therapy (PAGE4).

PAGE4 is an X chromosome-linked cancer testis antigen and is a potential new tumor-associated antigen that is overexpressed in prostate and uterine cancers. The purpose of this study was to identify a human CTL epitope and a corresponding agonist epitope of PAGE4 to determine if PAGE4 is a potential target for vaccine-mediated immunotherapy against PAGE4-expressing tumors. A class I PAGE4 epitope was identified with a high level of binding to HLA-A2. PAGE4 peptide-pulsed dendritic cells were then used to generate human PAGE4-specific T-cell lines. Further studies demonstrated the generation of an enhancer agonist epitope. Compared with the native peptide, the agonist (i) bound to HLA-A2 molecules at lower peptide concentrations, (ii) demonstrated a higher stability of the peptide HLA-A2 complex, (iii) induced higher levels of production of IFN-gamma, Granzyme B, TNF-alpha, IL-2 and lymphotactin by PAGE4-specific T-cell lines and (iv) T-cell lines generated against the agonist peptide were more efficient to lyse HLA-A2 human tumor cells expressing native PAGE4. The studies reported here are the first to describe a PAGE4 CTL epitope and its agonist epitope, and thus identify PAGE4 as a potentially useful target for vaccine-mediated therapy of prostate cancer.