Nicolas Mach

CCR9 is a homing receptor for plasmacytoid dendritic cells to the small intestine

Small intestine plasmacytoid dendritic cells (pDC) are poorly characterized. Here, we demonstrate that intestinal pDC show the characteristic plasma cell-like morphology, and are recognized by antibodies against B220, Ly6c, 120G8, and PDCA-1, markers that are typically expressed by pDC. Furthermore, intestinal pDC carry high levels of CCR9 and are largely absent in the intestine, but not in lung, liver, or secondary lymphoid organs of CCR9-deficient animals. Competitive adoptive transfers reveal that CCR9-deficient pDC are impaired in homing to the small intestine after i.v. transfer. In a model of cholera toxin-induced gut inflammation, pDC are recruited to the intestine in WT but not CCR9-deficient animals. Furthermore, after oral application of a Toll-like receptor (TLR) 7/8 ligand, myeloid DC of the lamina propria are rapidly mobilized in WT but not in CCR9-deficient animals. Mobilization of myeloid DC can be completely rescued by adoptively transferred WT pDC to CCR9-deficient mice before oral challenge. Together, our data reveal an essential role for CCR9 in the homing of pDC to the intestine under homeostatic and inflammatory conditions and demonstrate an important role for intestinal pDC for the rapid mobilization of lamina propria DC.

CD1d-restricted T cells regulate dendritic cell function and antitumor immunity in a granulocyte–macrophage colony-stimulating factor-dependent fashion

CD1d-restricted T cells contribute to tumor protection, but their precise roles remain unclear. Here we show that tumor cells engineered to secrete granulocyte–macrophage colony-stimulating factor induce the expansion of CD1d-restricted T cells through a mechanism that involves CD1d and macrophage inflammatory protein 2 expression by CD8α–, CD11c+ dendritic cells (DCs). The antitumor immunity stimulated by vaccination with irradiated, granulocyte-macrophage colony-stimulating factor-secreting tumor cells was abrogated in CD1d- and Jα281-deficient mice, revealing a critical role for CD1d-restricted T cells in this response. The loss of antitumor immunity was associated with impaired tumorinduced T helper 2 cytokine production, although IFN-γ secretion and cytotoxicity were preserved. DCs from immunized CD1d-deficient mice showed compromised maturation and function. Together, these results delineate a role for CD1d-restricted T cell–DC cross talk in the shaping of antitumor immunity.

Quality of life in patients with oropharynx carcinomas: assessment after accelerated radiotherapy with or without chemotherapy versus radical surgery and postoperative radiotherapy

In oropharyngeal carcinomas, it is assumed that the effectiveness of the different treatment approaches is roughly equivalent, whereas the functional outcome after radical radiotherapy (RT) is superior to that associated with primary surgery. The aim of this study is to assess quality of life (QoL) outcomes of patients after two treatment strategies: radical surgery with postoperative RT and accelerated concomitant boost RT with or without chemotherapy.

Phase I study of sorafenib combined with radiation therapy and temozolomide as first-line treatment of high-grade glioma

Background:Sorafenib (Sb) is a multiple kinase inhibitor targeting both tumour cell proliferation and angiogenesis that may further act as a potent radiosensitizer by arresting cells in the most radiosensitive cell cycle phase. This phase I open-label, noncontrolled dose escalation study was performed to determine the safety and maximum tolerated dose (MTD) of Sb in combination with radiation therapy (RT) and temozolomide (TMZ) in 17 patients with newly diagnosed high-grade glioma.Methods:Patients were treated with RT (60 Gy in 2 Gy fractions) combined with TMZ 75 mg m−2 daily, and Sb administered at three dose levels (200 mg daily, 200 mg BID, and 400 mg BID) starting on day 8 of RT. Thirty days after the end of RT, patients received monthly TMZ (150–200 mg m−2 D1–5/28) and Sb (400 mg BID). Pharmacokinetic (PK) analyses were performed on day 8 (TMZ) and on day 21 (TMZ&Sb) (Clinicaltrials ID: NCT00884416).Results:The MTD of Sb was established at 200 mg BID. Dose-limiting toxicities included thrombocytopenia (two patients), diarrhoea (one patient) and hypercholesterolaemia (one patient). Sb administration did not affect the mean area under the curve(0–24) and mean Cmax of TMZ and its metabolite 5-amino-imidazole-4-carboxamide (AIC). Tmax of both TMZ and AIC was delayed from 0.75 (TMZ alone) to 1.5 h (combined TMZ/Sb). The median progression-free survival was 7.9 months (95% confidence interval (CI): 5.4–14.55), and the median overall survival was 17.8 months (95% CI: 14.7–25.6).Conclusions:Although Sb can be combined with RT and TMZ, significant side effects and moderate outcome results do not support further clinical development in malignant gliomas. The robust PK data of the TMZ/Sb combination could be useful in other cancer settings.

Role of GM-CSF signaling in cell-based tumor immunization

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a potent adjuvant in cancer vaccination; however, the specific role of endogenous GM-CSF remains unknown. We performed cell-based vaccination in 2 tumor models. First, we vaccinated C57BL/6 mice lacking either GM-CSF, IL-5, or beta-common chain (betac), a receptor subunit essential for GM-CSF and IL-5 signaling, with melanoma cells engineered to produce GM-CSF. Tumor vaccination was effective in both GM-CSF(-/-) and IL-5(-/-) mice, showing that protective immunization is independent of both endogenous cytokines. However, all betac(-/-) animals developed tumor. Loss of tumor immunity in betac(-/-) mice does not reflect global impairment in cell-mediated immunity, as contact hypersensitivity reaction to haptens is unaltered. The importance of tumor cell-derived GM-CSF was highlighted by recruitment of dendritic cells at the vaccination site in wild-type, GM-CSF(-/-), and IL-5(-/-) but not in betac(-/-) mice. In the second model, vaccination with unmodified RENCA cells showed similar results with efficient immunization in BALB/c wild-type and GM-CSF(-/-), whereas all betac(-/-) animals died. Altogether, our results strongly suggest that although endogenous GM-CSF and IL-5 are not required to induce tumor immunity, signaling through betac receptor is critically needed for efficient cancer vaccination in both genetically modified GM-CSF-secreting tumor cells and a spontaneously immunogenic models.

Intestinal Colonization of IL-2 Deficient Mice with Non-Colitogenic B. vulgatus Prevents DC Maturation and T-Cell Polarization

Background IL-2 deficient (IL-2−/−) mice mono-colonized with E. coli mpk develop colitis whereas IL-2−/−-mice mono-colonized with B. vulgatus mpk do not and are even protected from E. coli mpk induced colitis. Methodology/Principal Findings We investigated if mono-colonization with E. coli mpk or B. vulgatus mpk differentially modulates distribution, activation and maturation of intestinal lamina propria (LP) dendritic cells (DC). LP DC in mice mono-colonized with protective B. vulgatus mpk or co-colonized with E. coli mpk/B. vulgatus mpk featured a semi-mature LP DC phenotype (CD40loCD80loMHC-IIhi) whereas mono-colonization with colitogenic E. coli mpk induced LP DC activation and maturation prior to onset of colitis. Accordingly, chemokine receptor (CCR) 7 surface expression was more strikingly enhanced in mesenteric lymph node DC from E. coli mpk than B. vulgatus mpk mono- or co-colonized mice. Mature but not semi-mature LP DC promoted Th1 polarization. As B. vulgatus mpk promotes differentiation of semi-mature DC presumably by IL-6, mRNA and protein expression of IL-6 was investigated in LP DC. The data demonstrated that IL-6 mRNA and protein was increased in LP DC of B. vulgatus mpk as compared to E. coli mpk mono-colonized IL-2−/−-mice. The B. vulgatus mpk mediated suppression of CCR7 expression and DC migration was abolished in IL-6−/−-DC in vitro. Conclusions/Significance From this data we conclude that the B. vulgatus triggered IL-6 secretion by LP DC in absence of proinflammatory cytokines such as IL-12 or TNF-α induces a semi-mature LP DC phenotype, which might prevent T-cell activation and thereby the induction of colitis in IL-2−/−-mice. The data provide new evidence that IL-6 might act as an immune regulatory cytokine in the mucosa by targeting intestinal DC.

Short Peptide Vaccine Induces CD4+ T Helper Cells in Patients with Different Solid Cancers

The possibility that short peptide vaccines induce antitumor CD4+ T-cell responses has been widely ignored. Peripheral blood from vaccinated patients revealed that short peptides often activate specific T helper cells, facilitating a strong combined CD4+ and CD8+ T-cell response. Previous cancer vaccination trials often aimed to activate CD8+ cytotoxic T-cell (CTL) responses with short (8–10mer) peptides and targeted CD4+ helper T cells (TH) with HLA class II–binding longer peptides (12–16 mer) that were derived from tumor antigens. Accordingly, a study of immunomonitoring focused on the detection of CTL responses to the short, and TH responses to the long, peptides. The possible induction of concurrent TH responses to short peptides was widely neglected. In a recent phase I vaccination trial, 53 patients with different solid cancers were vaccinated with EMD640744, a cocktail of five survivin-derived short (9- or 10-mer) peptides in Montanide ISA 51VG. We monitored 49 patients and found strong CD8+ T-cell responses in 63% of the patients. In addition, we unexpectedly found CD4+ TH cell responses against at least two of the five short peptides in 61% (23/38) of the patients analyzed. The two peptides were recognized by HLA-DP4– and HLA-DR–restricted TH1 cells. Some short peptide–reactive (sp)CD4 T cells showed high functional avidity. Here, we show that a short peptide vaccine is able to activate a specific CD4+ T-cell repertoire in many patients, facilitating a strong combined CD4+/CD8+ T-cell response. Cancer Immunol Res; 4(1); 18–25. ©2015 AACR.

Cell encapsulation technology as a novel strategy for human anti-tumor immunotherapy

Granulocyte-macrophage colony-stimulating factor (GM-CSF) as an adjuvant in autologous cell-based anti-tumor immunotherapy has recently been approved for clinical application. To avoid the need for individualized processing of autologous cells, we developed a novel strategy based on the encapsulation of GM-CSF-secreting human allogeneic cells. GM-CSF-producing K562 cells showed high, stable and reproducible cytokine secretion when enclosed into macrocapsules. For clinical development, the cryopreservation of these devices is critical. Thawing of capsules frozen at different time points displayed differences in GM-CSF release shortly after thawing. However, similar secretion values to those of non-frozen control capsules were obtained 8 days after thawing at a rate of >1000 ng GM-CSF per capsule every 24 h. For future human application, longer and reinforced capsules were designed. After irradiation and cryopreservation, these capsules produced >300 ng GM-CSF per capsule every 24 h 1 week after thawing. The in vivo implantation of encapsulated K562 cells was evaluated in mice and showed preserved cell survival. Finally, as a proof of principle of biological activity, capsules containing B16-GM-CSF allogeneic cells implanted in mice induced a prompt inflammatory reaction. The ability to reliably achieve high adjuvant release using a standardized procedure may lead to a new clinical application of GM-CSF in cell-based cancer immunization.

Phase I trial of concomitant hyperfractionated radiotherapy with docetaxel and cisplatin for locally advanced head and neck cancer

BACKGROUNDThis study was conducted to determine the maximum tolerated dose of docetaxel when administered concomitantly with radical hyperfractionated radiotherapy and cisplatin in patients with locally advanced head and neck cancer. PATIENTS AND METHODSPatients with stage III-IV tumors received radical radiotherapy of 74.4 Gy given in two daily fractions of 1.2 Gy for 6 weeks. Cisplatin was given once weekly on day 1 at a constant dose of 15 mg/m2. The starting dose of docetaxel was 10 mg/m2 once weekly on day 3, with planned escalation steps of 5 mg/m2. Main endpoints of the study were the maximum tolerated dose of docetaxel, acute toxicities, and the preliminary efficacy results. RESULTSTwenty-five patients were enrolled. Median follow-up was 15 months (range: 4–40 months). Two of three patients presented with dose-limiting toxicities at the 15-mg/m2 dose of docetaxel (one patient presented with multiple grade 3–4 toxicities requiring hospitalization for management and another presented with multiple toxicities including life-threatening bronchoaspiration). Thus, the weekly docetaxel dose of 10 mg/m2 was considered the maximum tolerated dose. Nineteen patients were then treated with the maximum tolerated dose and no dose-limiting toxicities were observed. Radiotherapy was completed in all patients except one (median dose: 74.4; range: 73.2–74.4), and at least 80% of the scheduled cisplatin and docetaxel doses were given in 92% of the patients. Acute toxicities were dominated by grade 3 mucositis (92%) and grade 3–4 dysphagia (68%). The 2.5-year actuarial local control rate was 87.5%, and the disease-free survival rate was 75%. At the time of last follow-up, 23 patients were alive and two had died from cancer. No distant metastases were observed. DISCUSSIONIn patients with locally advanced head and neck cancer, this study determined the maximum tolerated dose of docetaxel to be 10 mg/m2 administered once weekly when given concurrently with 74.4 Gy hyperfractionated radiotherapy and a weekly 15-mg/m2 dose of cisplatin. The toxicity profile and the encouraging results suggest that this new combination merits further investigation in a multi-institutional phase II trial.

Cytopathological Diagnosis of Non Small Cell Lung Cancer: RecentAdvances Including Rapid On-Site Evaluation, Novel EndoscopicTechniques and Molecular Tests

Important advances in non small cell lung cancer (NSCLC) diagnosis, staging and treatment have been made over the last decade. Minimally-invasive endoscopic techniques including endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) and navigational bronchoscopy have emerged as valid alternatives to transthoracic and/or surgical approaches, providing aspiration cytology material instead of histological material for diagnosis and staging of mediastinal and lung lesions. Several drugs designed to target molecular pathways involved in cancer-cell growth and survival have been shown to be effective in a selected fraction of NSCLC patients, mostly with adenocarcinoma (targeted therapy). Somatic activating mutations in several genes involved in those pathways (EGFR/KRAS) can predict patients’ responses to targeted therapies (individualized therapy). Those mutations are commonly detected in histopathological samples (core-needle biopsy/surgical resection). However, when histological tissues are not available, molecular testing can be performed on cytological specimens. This scenario is increasing in frequency, due to the use of less invasive procedure for diagnosis and staging such EBUS-TBNA and/or patients in advanced stage of disease who are not candidates for surgery. Several strategies exist and may be combined to ensure that the less abundant material that results from minimally invasive techniques can be used efficiently for molecular analyses. These include Rapid On-Site Evaluation (ROSE) of EBUS-TBNA cytological material, to ensure optimal sampling and triage of the material (e.g. cell-block preparation), and microdissection techniques, to select an adequate population of tumor cells. Major issues raised by cytological diagnosis of NSCLC and molecular testing on cytological specimen are discussed in this article.