Carlo Sorrentino

CD25 + Regulatory T Cell Depletion Augments Immunotherapy of Micrometastases by an IL-21-Secreting Cellular Vaccine

IL-21 is an IL-2-like cytokine, signaling through a specific IL-21R and the IL-2R γ-chain. Because the TS/A mammary adenocarcinoma cells genetically modified to secrete IL-21 (TS/A-IL-21) are strongly immunogenic in syngeneic mice, we analyzed their application as vaccine. In mice bearing TS/A-parental cell (pc) micrometastases, vaccination with irradiated TS/A-IL-21 cells significantly increased the animal life span, but cured only 17% of mice. Spleen cells from cured mice developed CTL activity and produced IFN-γ in response to stimulation by the AH1 epitope of the gp70env Ag of TS/A-pc. We tested whether the low therapeutic outcome might be due to CD4+CD25+ regulatory T cells (Treg) present in TS/A-pc tumors and draining lymph nodes and whether IL-21 had any effect on these cells. Indeed, CD4+CD25+ cells suppressed IFN-γ production by splenocytes from immune mice in response to stimulation by the AH1 peptide. Low concentrations of IL-21 (10 ng/ml) failed to reverse the inhibitory activity of CD4+CD25+ cells in an allogeneic MLR, whereas 60 ng/ml rIL-21 partially restored responder T cell proliferation. IL-21R expression on CD25− lymphocytes suggested that IL-21 could be more effective in mice depleted of CD25+ cells. Depletion of Treg cells by a single dose of anti-CD25 mAb combined with TS/A-IL-21 cell vaccine cured >70% of mice bearing micrometastases, whereas anti-CD25 mAb treatment alone had no effect. Successful combined immunotherapy required NK cells, CD8+ T cells, and IFN-γ. In conclusion, immunotherapy of micrometastases by an IL-21-based cellular vaccine is strongly potentiated by CD25+ cell depletion.

Crucial pathophysiological role of CXCR2 in experimental ulcerative colitis in mice.

Polymorphonuclear leukocyte infiltration and activation into colonic mucosa are believed to play a pivotal role in mediating tissue damage in human ulcerative colitis (UC). Ligands of human CXC chemokine receptor 1 and 2 (CXCR1/R2) are chemoattractants of PMN, and high levels were found in the mucosa of UC patients. To investigate the pathophysiological role played by CXCR2 in experimental UC, we induced chronic experimental colitis in WT and CXCR2−/− mice by two consecutive cycles of 4% dextran sulfate sodium administration in drinking water. In wild‐type (WT) mice, the chronic relapsing of DSS‐induced colitis was characterized by clinical signs and histopathological findings that closely resemble human disease. CXCR2−/− mice failed to show PMN infiltration into the mucosa and, consistently with a key role of PMN in mediating tissue damage in UC, showed limited signs of mucosal damage and reduced clinical symptoms. Our data demonstrate that CXCR2 plays a key pathophysiological role in experimental UC, suggesting that CXCR2 activation may represent a relevant pharmacological target for the design of novel pharmacological treatments in human UC.

Expression of IL-32 in Human Lung Cancer Is Related to the Histotype and Metastatic Phenotype

RATIONALE A strong link has been recently demonstrated between inflammation and lung cancer. Thus, we investigated whether the proinflammatory cytokine IL-32 may be involved in lung carcinogenesis and hence provide a novel therapeutic target. OBJECTIVES Lung cancer subtypes display different clinical outcomes. We have set out to clarify the role of IL-32 in the physiopathology of the main histotypes. METHODS IL-32 expression, as visualized by immunohistochemistry on 23 premalignant and 148 malignant lesions, was correlated with clinicopathological and survival data. Confocal microscopy, microdissection, and real-time reverse transcription-polymerase chain reaction were used to identify cell sources and expression levels of IL-32. MEASUREMENTS AND MAIN RESULTS IL-32 expression was lacking in the majority of squamous-cell carcinomas (SCC) (76%) and their precursor lesions, but strongly up-regulated in most adenocarcinomas (AC) (73%) and their precursors, 64% of large-cell carcinomas, and 77% of small-cell lung cancers. Lymph node metastases frequently developed from IL-32-expressing lung cancers, and especially (82%) from those endowed with an IL-32-expressing leukocyte infiltrate (TIL) mainly composed of CD68(+) macrophages, CD4(+) T lymphocytes, and DC-SIGN(+) dendritic cells. Expression levels of IL-32 by both TIL and tumor cells (TC), particularly in AC and SCC, were paralleled by those of IL-6, IL-8, and vascular endothelial growth factor in the same cell population and correlated with high intratumor microvessel density and poor clinical outcome. CONCLUSIONS IL-32 is probably implicated in the pathogenesis of most lung cancer histotypes but unlikely in that of SCC. Its TIL and TC expression are both associated with acquisition of an invasive and metastatic phenotype and may be a useful prognostic indicator.

Interleukin-27 Acts as Multifunctional Antitumor Agent in Multiple Myeloma

Purpose: Multiple myeloma (MM) derives from plasmablast/plasma cells that accumulate in the bone marrow. Different microenvironmental factors may promote metastatic dissemination especially to the skeleton, causing bone destruction. The balance between osteoclast and osteoblast activity represents a critical issue in bone remodeling. Thus, we investigated whether interluekin-27 (IL-27) may function as an antitumor agent by acting directly on MM cells and/or on osteoclasts/osteoblasts. Experimental Design: The IL-27 direct antitumor activity on MM cells was investigated in terms of angiogenesis, proliferation, apoptosis, and chemotaxis. The IL-27 activity on osteoclast/osteoblast differentiation and function was also tested. In vivo studies were done using severe combined immunodeficient/nonobese diabetic mice injected with MM cell lines. Tumors from IL-27– and PBS-treated mice were analyzed by immunohistochemistry and PCR array. Results: We showed that IL-27 (a) strongly inhibited tumor growth of primary MM cells and MM cell lines through inhibition of angiogenesis, (b) inhibited osteoclast differentiation and activity and induced osteoblast proliferation, and (c) damped in vivo tumorigenicity of human MM cell lines through inhibition of angiogenesis. Conclusions: These findings show that IL-27 may represent a novel therapeutic agent capable of inhibiting directly MM cell growth as well as osteoclast differentiation and activity. Clin Cancer Res; 16(16); 4188–97. ©2010 AACR.

The IL-12Rβ2 gene functions as a tumor suppressor in human B cell malignancies

The IL-12Rβ2 gene is expressed in human mature B cell subsets but not in transformed B cell lines. Silencing of this gene may be advantageous to neoplastic B cells. Our objective was to investigate the mechanism(s) and the functional consequence(s) of IL-12Rβ2 gene silencing in primary B cell tumors and transformed B cell lines. Purified tumor cells from 41 patients with different chronic B cell lymphoproliferative disorders, representing the counterparts of the major mature human B cell subsets, tested negative for IL-12Rβ2 gene expression. Hypermethylation of a CpG island in the noncoding exon 1 was associated with silencing of this gene in malignant B cells. Treatment with the DNA methyltransferase inhibitor 5-Aza-2′-deoxycytidine restored IL-12Rβ2 mRNA expression in primary neoplastic B cells that underwent apoptosis following exposure to human recombinant IL-12 (hrIL-12). hrIL-12 inhibited proliferation and increased the apoptotic rate of IL-12Rβ2–transfected B cell lines in vitro. Finally, hrIL-12 strongly reduced the tumorigenicity of IL-12Rβ2–transfected Burkitt lymphoma RAJI cells in SCID-NOD mice through antiproliferative and proapoptotic effects, coupled with neoangiogenesis inhibition related to human IFN-γ–independent induction of hMig/CXCL9. The IL-12Rβ2 gene acts as tumor suppressor in chronic B cell malignancies, and IL-12 exerts direct antitumor effects on IL-12Rβ2–expressing neoplastic B cells.

Quilty effect has the features of lymphoid neogenesis and shares CXCL13-CXCR5 pathway with recurrent acute cardiac rejections

Quilty effect (QE) is a frequent, yet enigmatic feature of cardiac allograft, since it is apparently devoid of clinical significance, though its association with acute (A) rejection (R) is strongly suspected.

Androgen Deprivation Boosts Prostatic Infiltration of Cytotoxic and Regulatory T Lymphocytes and Has No Effect on Disease-Free Survival in Prostate Cancer Patients

Purpose: The value of neoadjuvant hormone therapy (NHT) prior to radical prostatectomy as a means of restraining prostate cancer (PCa) and strengthening its immunotherapy is still uncertain. This article asks whether it subverts immunoregulatory pathways governing tumor microenvironments, and has an impact on patient outcome. Experimental Design: We microdissected epithelium and stroma from cancerous and normal prostate specimens from 126 prostatectomized patients, of whom 76 had received NHT, to detect cytokine/chemokine gene expression levels by real-time reverse transcriptase PCR. Confocal microscopy was used to identify cytokine/chemokine cell sources, and immunostainings to characterize lymphocyte subsets whose prognostic effects were assessed by Kaplan–Meier analyses. Results: NHT boosted the expression of IL-7 in the stroma and that of IFNγ-inducible protein-10/CXCL10 in the glandular epithelium of normal prostate tissue, and restored the CD8+ lymphocyte depletion occurring in PCa, whereas it significantly increased the CD4+ lymphocyte infiltrate. Lymphocytes, mostly with CD8+ phenotype, expressed the T-cell intracellular antigen-1, granzyme-B, and perforin, typical of cytotoxic-effector T cells. NHT also induced thymus and activation-regulated chemokine/CCL17 production by monocytes/macrophages in the prostate and draining lymph nodes, and increased the number of their Forkhead box P3 (Foxp3)+CD25+CD127− T regulatory (Treg) cells. The χ2 test disclosed the lack of association (P = 0.27) between NHT and the high intratumoral CD8+/Treg ratio indicative of a good prognosis. Conclusions: Androgen withdrawal regulates cytokine/chemokine gene expression in normal prostate and lymphoid tissues, and this probably favors both CD8+ and Treg infiltrates, leaves their intratumoral balance unchanged, and thus has no impact on disease-free survival. Clin Cancer Res; 17(6); 1571–81. ©2010 AACR.

Direct inhibition of human acute myeloid leukemia cell growth by IL-12

Acute myeloid leukemia is a haematopoietic malignancy originating from the transformation of myeloid progenitors that proliferate and accumulate in the bone marrow. In AML patients the survival rate at 5 years is 40-50% highlighting the need for novel therapies. In this study we have asked whether IL-12, an immuno-modulatory cytokine with anti-tumor activity, may inhibit directly AML cell growth. We show that the human AML cell lines U937, K562 and THP-1 expressed both chains of the IL-12 receptor (R), i.e. IL-12Rβ1 and IL-12Rβ2. IL-12 inhibited the angiogenic potential of AML cells in vitro, but did not affect their survival or proliferation. In vivo experiments were performed using SCID-NOD mice injected intraperitoneally (i.p.) with the human U937 AML cell line and subsequently treated with human recombinant IL-12 or PBS i.p. Histological, immunohistochemical and flow cytometric analyses on explanted tumors revealed that IL-12 reduced new vessel formation, induced apoptosis and inhibited tumor cell proliferation. Studies on a panel of angiogenesis related genes in explanted tumors using PCR arrays showed significantly down-regulated expression of numerous pro-angiogenic genes including VEGF-C, IL-6, IL-8, CXCL1, CXCL6 and alanyl aminopeptidase in IL-12 vs PBS treated mice. This study shows for the first time that IL-12 targets directly AML cell growth and paves the way to further investigation of IL-12 as potential drug for AML treatment.

Endomyocardial infiltration by B and NK cells foreshadows the recurrence of cardiac allograft rejection.

Heart allograft outcome is unpredictable and acute rejection episodes still occur despite the improvement of immunosuppressive regimens. We therefore investigated whether the immunopathological profile of endomyocardial biopsies might underlie the variations in the clinical course of a graft. Biopsies from transplanted patients were analysed by histology, immunohistochemistry (associated with digital image analysis), confocal and electron microscopy to determine the type and the functional state of leukocytes infiltrating the myocardium, together with their ultrastructural features and those of the graft itself. In comparison with biopsies with grade 0R or grade 1R rejection, those from patients with grade 2R rejection displayed significant infiltration of macrophages, T lymphocytes, and CD83+ and DC‐SIGN+ dendritic cells. Fifty‐seven per cent were invaded by CD20+B lymphocytes, most of which expressed CD69 activation marker and cooperated in interleukin‐12 production, and by CD69+CD94+NK cells expressing interferon‐γ. Ultrastructural signs of myocyte degeneration and microvessel rupture by NK cells were frequent. These patients developed recurrent episodes of acute allograft rejection. Endomyocardial B and NK infiltrates are involved in the dynamics of allograft rejection and are associated with a high risk of its recurrence. Immunopathological assessment of endomyocardial biopsies may thus serve to forecast the probable outcome of a heart allograft. Copyright

IL-12 Can Target Human Lung Adenocarcinoma Cells and Normal Bronchial Epithelial Cells Surrounding Tumor Lesions

Background Non small cell lung cancer (NSCLC) is a leading cause of cancer death. We have shown previously that IL-12rb2 KO mice develop spontaneously lung adenocarcinomas or bronchioalveolar carcinomas. Aim of the study was to investigate i) IL-12Rβ2 expression in human primary lung adenocarcinomas and in their counterparts, i.e. normal bronchial epithelial cells (NBEC), ii) the direct anti-tumor activity of IL-12 on lung adenocarcinoma cells in vitro and vivo, and the mechanisms involved, and iii) IL-12 activity on NBEC. Methodology/Principal Findings Stage I lung adenocarcinomas showed significantly (P = 0.012) higher frequency of IL-12Rβ2 expressing samples than stage II/III tumors. IL-12 treatment of IL-12R+ neoplastic cells isolated from primary adenocarcinoma (n = 6) inhibited angiogenesis in vitro through down-regulation of different pro-angiogenic genes (e.g. IL-6, VEGF-C, VEGF-D, and laminin-5), as assessed by chorioallantoic membrane (CAM) assay and PCR array. In order to perform in vivo studies, the Calu6 NSCLC cell line was transfected with the IL-12RB2 containing plasmid (Calu6/β2). Similar to that observed in primary tumors, IL-12 treatment of Calu6/β2+ cells inhibited angiogenesis in vitro. Tumors formed by Calu6/β2 cells in SCID/NOD mice, inoculated subcutaneously or orthotopically, were significantly smaller following IL-12 vs PBS treatment due to inhibition of angiogenesis, and of IL-6 and VEGF-C production. Explanted tumors were studied by histology, immuno-histochemistry and PCR array. NBEC cells were isolated and cultured from lung specimens of non neoplastic origin. NBEC expressed IL-12R and released constitutively tumor promoting cytokines (e.g. IL-6 and CCL2). Treatment of NBEC with IL-12 down-regulated production of these cytokines. Conclusions This study demonstrates that IL-12 inhibits directly the growth of human lung adenocarcinoma and targets the adjacent NBEC. These novel anti-tumor activities of IL-12 add to the well known immune-modulatory properties of the cytokine and may provide a rational basis for the development of a clinical trial.