Advances in Cellular Therapy for the Treatment of Thyroid Cancer

Up to now, there are no curative therapies available for the subset of metastasized undifferentiated/anaplastic thyroid carcinomas. This review describes the possible use of immunocompetent cells which may help to restore the antitumor immune recognition for treating an existing tumor or preventing its recurrence. The most prominent experimental strategy is the use of dendritic cells (DCs) which are highly potent in presenting tumor antigens. Activated DCs subsequently migrate to draining lymph nodes where they present antigens to naïve lymphocytes and induce cytotoxic T cells (CTL). Alternatively to DC therapy, adoptive cell transfer may be performed by either using natural killer cells or ex vivo maturated CTLs. Within this review article we will focus on recent advances in the understanding of anti-tumor immune responses, for example, in thyroid carcinomas including the advances which have been made for the identification of potential tumor antigens in thyroid malignancies

Bedeutung von DNA-Reparaturprozessen für die Zytostatika-Resistenz menschlicher Leukämie-Zellen

In dieser Arbeit wurde untersucht, welche Bedeutung DNA-Reparaturprozesse für die Empfindlichkeit humaner Tumorzellen gegenüber DNA-reaktiven Chemotherapeutika haben. Dazu wurden zunächst zwei Analyseverfahren etabliert, die eine quantitative Bestimmung der DNA-Reparaturkapazität auf der Ebene einzelner Zellen erlaubten: die immunzytochemische Analyse (ICA) zur Messung spezifischer DNA-Alkylierungsprodukte und die Einzelzell-Gelelektrophorese (?Comet Assay?) zur Bestimmung Reparatur-induzierter DNA-Strangbrüche. Funktionelle Messungen an humanen Normal-Lymphozyten, die ex vivo mit einem Standard-Alkylanz (EtNU) behandelt wurden, wiesen auf eine nur geringe inter-zelluläre aber eine große inter-individuelle Varianz der DNA-Reparaturkapazität hin. Der Beitrag spezifischer Mechanismen bei der Prozessierung von EtNU-induzierten DNA-Läsionen wurde durch die funktionelle Blockierung einzelner Reparaturwege ermittelt. Als Untersuchungsmodell einer malignen Erkrankung, bei der die Resistenzentwicklung gegen Alkylantien ein großes klinisches Problem darstellt, wurde die chronisch lymphatische Leukämie (CLL) gewählt. Homogene Populationen monoklonaler primärer Tumorzellen sind aus dem peripheren Blut von Patienten als CLL-Lymphozyten verfügbar. Auch hier fand sich, ähnlich wie bei normalen Lymphozyten, eine große Bandbreite individueller Reparaturkapazitäten, sowohl für initiale DNA-Alkylierungsschäden als auch für die Prozessierung von sekundären Strangbrüchen. Extreme individuelle Unterschiede im relativen Beitrag einzelner Reparaturwege weisen aber auf einen Verlust von stringenter Regulation in diesem komplexen Netzwerk bei Tumorzellen hin. Die Analyse dieser Daten mit parallel durchgeführten Zytotoxizitätsbestimmungen zeigte, daß die Reparatur-Halbwertszeiten für DNA-Läsionen bei CLL-Lymphozyten signifikant korrelieren mit deren in vitro-Chemosensitivität gegenüber einer Reihe von Alkylantien, die unterschiedliche Muster von DNA-Schäden induzieren. Dieser Befund legt einen kausalen Zusammenhang zwischen zellulärer Reparaturkapazität und dem Chemoresistenzprofil von Tumorzellen nahe

Monocyte derived dendritic cells generated by IFN-α acquire mature dendritic and natural killer cell properties as shown by gene expression analysis

<p>Abstract</p> <p>Background</p> <p>Dendritic cell (DC) vaccines can induce antitumor immune responses in patients with malignant diseases, while the most suitable DC culture conditions have not been established yet. In this study we compared monocyte derived human DC from conventional cultures containing GM-CSF and IL-4/TNF-α (IL-4/TNF-DC) with DC generated by the novel protocol using GM-CSF and IFN-α (IFN-DC).</p> <p>Methods</p> <p>To characterise the molecular differences of both DC preparations, gene expression profiling was performed using Affymetrix microarrays. The data were conformed on a protein level by immunophenotyping, and functional tests for T cell stimulation, migration and cytolytic activity were performed.</p> <p>Results</p> <p>Both methods resulted in CD11c+ CD86+ HLA-DR+ cells with a typical DC morphology that could efficiently stimulate T cells. But gene expression profiling revealed two distinct DC populations.</p> <p>Whereas IL-4/TNF-DC showed a higher expression of genes envolved in phagocytosis IFN-DC had higher RNA levels for markers of DC maturity and migration to the lymph nodes like DCLAMP, CCR7 and CD49d. This different orientation of both DC populations was confined by a 2.3 fold greater migration in transwell experiments (p = 0.01).</p> <p>Most interestingly, IFN-DC also showed higher RNA levels for markers of NK cells such as TRAIL, granzymes, KLRs and other NK cell receptors. On a protein level, intracytoplasmatic TRAIL and granzyme B were observed in 90% of IFN-DC. This translated into a cytolytic activity against K562 cells with a median specific lysis of 26% at high effector cell numbers as determined by propidium iodide uptake, whereas IL-4/TNF-DC did not induce any tumor cell lysis (p = 0.006). Thus, IFN-DC combined characteristics of mature DC and natural killer cells.</p> <p>Conclusion</p> <p>Our results suggest that IFN-DC not only stimulate adaptive but also mediate innate antitumor immune responses. Therefore, IFN-DC should be evaluated in clinical vaccination trials. In particular, this could be relevant for patients with diseases responsive to a treatment with IFN-α such as Non-Hodgkin lymphoma or chronic myeloid leukemia.</p

IFN-DC have novel molecular, phenotypical and functional characteristics in comparison to IL-4/TNF-DC

<p><b>Copyright information:</b></p><p>Taken from "Monocyte derived dendritic cells generated by IFN-α acquire mature dendritic and natural killer cell properties as shown by gene expression analysis"</p><p>http://www.translational-medicine.com/content/5/1/46</p><p>Journal of Translational Medicine 2007;5():46-46.</p><p>Published online 25 Sep 2007</p><p>PMCID:PMC2064912.</p><p></p> (a) Hierarchical cluster analysis of 52 genes related to NK cell function (rows) for IFN-DC and IL-4/TNF-DC preparations (columns) with expression levels obtained by Affymetrix microarray analysis. The colour scale indicates upregulation (green) and downregulation (red) of gene expression in relation to the mean expression levels of all preparations. (b) Corroboration of the microarray data by quantitative real-time PCR. The ΔCt values of 10 genes with β2-microglobulin as a reference gene were measured. Differences of the relative expression (mean ΔΔCt) of each gene were compared to the log2 of the fold change determined by microarray technology. (c) Expression of cytolytic effector molecules by DC. The intracellular expression of TRAIL and granzyme B by IFN-DC and IL-4/TNF-DC was analyzed by flow cytometry after permeabilization of cell membranes. The results are shown as mean ± SD of % positive cells. (d) Cytolytic activity of DC. Specific lysis of tumor cells by DC was measured by flow cytometric detection of propidium iodide uptake after coculture of 1 × 10CFDA-SE labeled K562 cells with different numbers of IFN-DC and IL-4/TNF-DC as indicated by the effector : target ratios. IL-2 activated NK-cells were used as a positive, and B cells as negative control. Significant differences between IFN-DC and IL-4/TNF-DC at different effector : target ratios are indicated by an asterisk (p < 0.05)