Gunter Rappl

Increased Serum Concentration of Angiogenic Factors in Malignant Melanoma Patients Correlates With Tumor Progression and Survival

PURPOSE To determine the predictive value of the angiogenic serum factors angiogenin, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and interleukin-8 (IL-8) for the prognosis of patients with malignant melanoma. PATIENTS AND METHODS Angiogenin, VEGF, bFGF, and IL-8 were measured in sera of 125 melanoma patients with different stages of disease and with or without current therapy including interferon alfa and different cytostatics in comparison with 30 healthy controls using enzyme-linked immunosorbent assay. RESULTS Serum levels of angiogenin, VEGF, bFGF, and IL-8 were significantly increased in melanoma patients compared with healthy controls. Elevated serum concentrations of VEGF, bFGF, and IL-8 were associated with advanced disease stages and tumor burden. Cytostatic therapy of patients was accompanied by increased serum levels of angiogenin, bFGF, and IL-8. As shown by univariate analysis, elevated serum levels of VEGF (P = .0001 and .0036), bFGF (P < .00005 and < .00005), and IL-8 (P < .00005 and < .00005) were strongly correlated with a poor overall and progression-free survival, respectively. Multivariate analysis revealed stage of disease (P = .0238), tumor burden (P = .0347), VEGF (P = .0036), bFGF (P = .0252), and IL-8 (P = .0447) as independent predictive factors of overall survival. Tumor burden (P = .0081), VEGF (P = .0245), and IL-8 (P = .0089) were found as independent predictive factors of progression-free survival. CONCLUSION Our data suggest that the angiogenic serum factors VEGF, bFGF, and IL-8 are useful predictive markers for overall and progression-free survival in melanoma patients.

Mitofusin 2 is required to maintain mitochondrial coenzyme Q levels

Mitofusin 2 plays an unexpected role in maintaining the terpenoid biosynthesis pathway and is necessary for mitochondrial coenzyme Q biosynthesis.

TCF/Lef1 activity controls establishment of diverse stem and progenitor cell compartments in mouse epidermis

Mammalian epidermis consists of the interfollicular epidermis, hair follicles (HFs) and associated sebaceous glands (SGs). It is constantly renewed by stem and progenitor cell populations that have been identified and each compartment features a distinct mechanism of cellular turnover during renewal. The functional relationship between the diverse stem cell (SC) pools is not known and molecular signals regulating the establishment and maintenance of SC compartments are not well understood. Here, we performed lineage tracing experiments to demonstrate that progeny of HF bulge SCs transit through other SC compartments, suggesting a hierarchy of competent multipotent keratinocytes contributing to tissue renewal. The bulge was identified as a bipotent SC compartment that drives both cyclic regeneration of HFs and continuous renewal of SGs. Our data demonstrate that aberrant signalling by TCF/Lef1, transcription factors crucial for bulge SC activation and hair differentiation, results in development of ectopic SGs originating from bulge cells. This process of de novo SG formation is accompanied by the establishment of new progenitor niches. Detailed molecular analysis suggests the recapitulation of steps of tissue morphogenesis.

T Cells That Target Carcinoembryonic Antigen Eradicate Orthotopic Pancreatic Carcinomas Without Inducing Autoimmune Colitis in Mice

BACKGROUND & AIMS New treatment approaches are needed for patients with pancreatic adenocarcinoma. Carcinoembryonic antigen (CEA) is highly expressed on the surface of pancreatic adenocarcinoma cells; we investigated the effects of cytolytic T cells that recognize CEA in a mouse model of pancreatic carcinoma. METHODS Immune-competent mice that expressed the CEA transgene (CEAtg) in the intestinal and pulmonary tracts were given intrapancreatic injections of Panc02 CEA(+) cells (express CEA and click beetle luciferase) and tumors were grown for 10 days. Mice were then given single intravenous injections of T cells engineered to express a chimeric antigen receptor (CAR) with high specificity, but moderate affinity, for CEA and a luminescence marker. RESULTS Injection of the anti-CEA CAR T cells reduced the size of pancreatic tumors to below the limit of detection in all mice and produced long-term tumor eradication in 67% of mice. T cells also eradicated CEA(+) fibrosarcoma cells injected 45 days later. Bioluminescence imaging revealed the accumulation and persistence of the T cells at the tumor site. The efficacy of the T cells did not require lymphodepletion and was not reduced by soluble CEA. Mice developed some noninflammatory infiltrations of CAR(+) T cells in intestine and lung, but there was no evidence of destruction of CEA(+) healthy tissues. CONCLUSIONS Injection of T cells that target CEA can eradicate tumors grown from CEA(+) pancreatic carcinoma cells in the pancreas of CEAtg mice without autoimmune effects.

CD28 Costimulation Impairs the Efficacy of a Redirected T-cell Antitumor Attack in the Presence of Regulatory T cells Which Can Be Overcome by Preventing Lck Activation

Adoptive T-cell transfer showed promising efficacy in recent trials raising interest in T cells with redirected specificity against tumors. T cells were engineered with a chimeric antigen receptor (CAR) with predefined binding and CD3ζ signaling to initiate T-cell activation. CD28 costimulation provided by a CD28-CD3ζ signaling CAR moreover improved T cell activation and persistence; however, it failed to meet the expectations with respect to mounting attacks against solid tumors infiltrated with regulatory T (Treg) cells. We revealed that a CD28 CAR-redirected T-cell attack is accompanied by higher numbers of Treg cells infiltrating the tumor and is less efficient against cancer cells in presence of Treg cells than a CD3ζ CAR T-cell attack. Deletion of the lck binding moiety in the CD28 CAR endodomain, however, improved redirected anti-tumor activity in presence of Treg cells without impairing interferon-γ (IFN-γ) secretion, proliferation, and cytolysis. CD28 modification abrogated interleukin-2 (IL-2) induction upon CAR engagement which in turn is no longer available to sustain Treg cell persistence. CARs with the modified CD28 endodomain thereby expedite the implementation of adoptive T-cell therapy in patients with a variety of cancer types that are heavily infiltrated by Treg cells.

Effective Proliferation of Human Regulatory T Cells Requires a Strong Costimulatory CD28 Signal That Cannot Be Substituted by IL-2

The strength of immune repression by regulatory T (Treg) cells is thought to depend on the efficiency of Treg cell activation. The stimuli and their individual strength required to activate resting human Treg cells, however, have so far not been elucidated in detail. We reveal here that induction of proliferation of human CD4+C25+ Treg cells requires an extraordinary strong CD28 costimulatory signal in addition to TCR/CD3 engagement. CD28 costimulation, noteworthy, cannot be substituted by IL-2 to induce proliferation of Treg cells, which is in contrast to CD4+CD25− T cells. IL-2, in contrast, prevents spontaneous apoptosis of Treg cells, but does not initiate their amplification. IL-2 and CD28 costimulation clearly exhibit disparate effects on Treg cells which are in contrast to those on CD4+CD25− T cells. Moreover, the prerequisites for Treg cell proliferation differ strikingly from those for effector T cells, implying a balanced orchestration in initiating and limiting a T cell immune response. In addition, data are of relevance for the design of therapeutic strategies involving IL-2 administration and CD28 costimulation.

Human CD4+ T Cells Lyse Target Cells via Granzyme/Perforin upon Circumvention of MHC Class II Restriction by an Antibody-Like Immunoreceptor

Immune elimination of tumor cells requires the close cooperation between CD8+ CTL and CD4+ Th cells. We circumvent MHC class II-restriction of CD4+ T cells by expression of a recombinant immunoreceptor with an Ab-derived binding domain redirecting specificity. Human CD4+ T cells grafted with an immunoreceptor specific for carcinoembryonic Ag (CEA) are activated to proliferate and secrete cytokines upon binding to CEA+ target cells. Notably, redirected CD4+ T cells mediate cytolysis of CEA+ tumor cells with high efficiencies. Lysis by redirected CD4+ T cells is independent of death receptor signaling via TNF-α or Fas, but mediated by perforin and granzyme because cytolysis is inhibited by blocking the release of cytotoxic granules, but not by blocking of Fas ligand or TNF-α. CD4+ T cells redirected by Ab-derived immunoreceptors in a MHC class II-independent fashion substantially extend the power of an adoptive, Ag-triggered immunotherapy not only by CD4+ T cell help, but also by cytolytic effector functions. Because cytolysis is predominantly mediated via granzyme/perforin, target cells that are resistant to death receptor signaling become sensitive to a cytolytic attack by engineered CD4+ T cells.

Regulatory T cells with reduced repressor capacities are extensively amplified in pulmonary sarcoid lesions and sustain granuloma formation

Sarcoidosis can evolve into a chronic disease with persistent granulomas accompanied by progressive fibrosis. While an unlimited inflammatory response suggests an impaired immune control in sarcoid lesions, it stands in contrast to the massive infiltration with CD4(+)CD25(high)FoxP3(+) regulatory T cells. We here revealed that those Treg cells in affected lung lesions were mainly derived from activated natural Treg cells with GARP (LRRC32)-positive phenotype but exhibited reduced repressor capacities despite high IL-10 and TGF-beta 1 levels. The repressive capacity of blood Treg cells, in contrast, was not impaired compared to age-matched healthy donors. Treg derived cells in granuloma lesions have undergone extensive rounds of amplifications indicated by shortened telomeres compared to blood Treg cells of the same patient. Lesional Treg derived cells moreover secreted pro-inflammatory cytokines including IL-4 which sustains granuloma formation through fibroblast amplification and the activation of mast cells, the latter indicated by the expression of membrane-bound oncostatin M.

Depletion of annexin A5, annexin A6, and collagen X causes no gross changes in matrix vesicle–mediated mineralization, but lack of collagen X affects hematopoiesis and the Th1/Th2 response

Numerous biochemical studies have pointed to an essential role of annexin A5 (AnxA5), annexin A6 (AnxA6), and collagen X in matrix vesicle–mediated biomineralization during endochondral ossification and in osteoarthritis. By binding to the extracellular matrix protein collagen X and matrix vesicles, annexins were proposed to anchor matrix vesicles in the extracellular space of hypertrophic chondrocytes to initiate the calcification of cartilage. However, mineralization appears to be normal in mice lacking AnxA5 and AnxA6, whereas collagen X–deficient mice show only subtle alterations in the growth plate organization. We hypothesized that the simultaneous lack of AnxA5, AnxA6, and collagen X in vivo induces more pronounced changes in the growth plate development and the initiation of mineralization. In this study, we generated and analyzed mice deficient for AnxA5, AnxA6, and collagen X. Surprisingly, mice were viable, fertile, and showed no obvious abnormalities. Assessment of growth plate development indicated that the hypertrophic zone was expanded in Col10a1−/− and AnxA5−/−AnxA6−/−Col10a1−/− newborns, whereas endochondral ossification and mineralization were not affected in 13‐day‐ and 1‐month‐old mutants. In peripheral quantitative computed tomography, no changes in the degree of biomineralization were found in femora of 1‐month‐ and 1‐year‐old mutants even though the diaphyseal circumference was reduced in Col10a1−/− and AnxA5−/−AnxA6−/−Col10a1−/− mice. The percentage of naive immature IgM+/IgM+ B cells and peripheral T‐helper cells were increased in Col10a1−/− and AnxA5−/−AnxA6−/−Col10a1−/− mutants, and activated splenic T cells isolated from Col10a1−/− mice secreted elevated levels of IL‐4 and GM‐CSF. Hence, collagen X is needed for hematopoiesis during endochondral ossification and for the immune response, but the interaction of annexin A5, annexin A6, and collagen X is not essential for physiological calcification of growth plate cartilage. Therefore, annexins and collagen X may rather fulfill functions in growth plate cartilage not directly linked to the mineralization process.

Adoptive Immunotherapy with Redirected T Cells Produces CCR7− Cells That Are Trapped in the Periphery and Benefit from Combined CD28-OX40 Costimulation

Adoptive therapy of cancer with genetically redirected T cells showed spectacular efficacy in recent trials. A body of preclinical and clinical data indicate that young effector and central memory T cells perform superior in a primary antitumor response; repetitive antigen engagement, however, drives T-cell maturation to terminally differentiated cells associated with the loss of CCR7, which enables T cells to persist in peripheral tissues. In this work, we explored the antitumor efficacy of CCR7(-) T cells when redirected in an antigen-dependent fashion by a chimeric antigen receptor (CAR) toward tumors in the periphery. CAR-engineered CCR7(-) T cells more efficiently accumulated at the tumor site, secreted more IFN-γ, expressed higher amounts of cytotoxic molecules, and showed superior tumor cell lysis compared to the younger CCR7(+) cells. CCR7(-) T cells, however, were more prone to spontaneous and activation-induced cell death, which could be counteracted by simultaneous CD28 and OX40 (CD134) costimulation. Consequently, the combined CD28-ζ-OX40 signaling CAR rescued CCR7(-) T cells from apoptosis, which then produced more efficient antitumor efficacy than CCR7(+) T cells redirected by the same CAR. Data suggest that T-cell therapy will benefit from combined CD28-ζ-OX40 stimulation in the long-term by rescuing continuously generated CCR7(-) T cells for an antitumor attack.