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Background: T cell receptor gene transfer is a promising strategy to treat patients suffering from HPV induced malignancies. Therefore we isolated the TCRαβ open reading frames of an HPV16E6 specific CTL clone and generated TCR transgenic T cells. In general low level expression of the transgenic TCR in recipient human T cells is observed as well as the formation of mixed TCRs dimers. Here we addressed both issues employing three different expression platforms.Methods: We isolated the HVP16E6 specific TCRα and TCRβ open reading frames and retrovirally transduced human T cells with either wild-type (wt), or codon-modified (cm) chains to achieve enhanced TCR expression levels, or used codon-modification in combination with cysteinization (cmCys) of TCRs to facilitate preferential pairing of the introduced TCRα and TCRβ chains.Results: Careful analysis of recipient T cells carrying the HPV16E6 TCRβ and endogenous TCR chains revealed the transgenic TCRβ chain to behave very promiscuously. Further analysis showed that the percentage of tetramer positive T cells in codon-modified/cysteinized TCR transgenic T cells was four-fold higher compared to wild-type and two-fold higher compared to codon-modification only. Functional activity, as determined by IFN-γ production, was high in cmCysTCR transgenic T cells, where it was low in cm and wt TCR transgenic T cells. Recognition of endogenously processed HPV16E6 antigen by cmCysTCR transgenic T cells was confirmed in a cytotoxicity assay.Conclusions: Promiscuous behavior of the HPV16E6 specific TCRβ chain can in part be forced back into specific action in TCR transgenic T cells by codon modification in combination with the inclusion of an extra cysteine in the TCR chains.

Background: Sentinel Lymph Node (SLN) status is strongly related to clinical outcome in melanoma patients. In this study we investigated the possible association between the presence of activated and/or suppressive Tumour Infiltrating Lymphocytes (TILs) and SLN status in clinically stage I/II melanoma patients.Methods: Diagnostic primary melanoma samples from 20 patients with a sentinel lymph node metastasis were compared to melanoma samples from 20 patients with a negative sentinel lymph node, who were matched for gender, age and Breslow thickness. Presence of activated Granzyme B positive (GrB+) TILs, presence of suppressive (FoxP3+) TILs and MHC class I antigen expression on tumour cells were analysed by immunohistochemistry.Results: FoxP3 and MHC-I expression had no direct bearing on the presence of melanoma metastases in the SLN. Whereas the presence of activated GrB+ TILs in the primary melanoma had no predictive value for SLN status either, their absence was strongly associated with the presence of metastasis in the SLN (p=0.001). While both GrB+ and FoxP3+ TILs could be detected in SLN metastases, a majority did not display MHC-I expression.Conclusions: These data support a role for cytotoxic T cells in the prevention of early metastasis of melanoma to the draining lymph nodes.

Background: Increasing data from clinical trials support EGFR and K-ras mutation status as predictive markers of tumour response to EGFR-targeted therapies. Consequently, rapid and reliable mutation screening assays are demanded to guide rational use of EGFR-targeted therapies.Methods: In this study, we describe the development of high resolution melting (HRM) technology-based assays with direct sequencing confirmation possibility for mutation screening of the EGFR gene (exons 19, 20 and 21) in routine diagnostic specimens, and compared assay findings to those of conventional nested-PCR following cycle-sequencing.Results: In reconstruction experiments, each HRM assay following sequencing demonstrated a sensitivity of ≤5% of mutated DNA in a background of wild-type DNA. The panel of EGFR HRM assays following sequencing applied to a series of genomic DNA samples isolated from 68 FFPE NSCLC specimens correctly identified all EGFR mutations that were previously found by nested-PCR following cycle-sequencing. The HRM approach additionally scored two mutations not detected by the conventional assay.Complementary HRM following sequencing for K-ras revealed three mutations. EGFR and K-ras mutations were mutually exclusive.Conclusions: The panel of designed HRM assays with direct reflex sequencing possibility provides an effective method for mutation screening of EGFR and K-ras genes in routine diagnostic specimens, thereby allowing the selection of the treatment of choice in clinical practice.

Background: Increasing evidence points to a negative correlation between K-ras mutations and patient’s response to, or survival benefit after, treatment with EGFR-inhibitors. Therefore, rapid and reliable assays for mutational analysis of the K-ras gene are strongly needed.Methods: We designed a high resolution melting (HRM) technology-based approach followed by direct sequencing to determine K-ras exon 1 (codons 12/13) tumour genotype.Results: Reconstruction experiments demonstrated an analytical sensitivity of the K-ras exon 1 HRM assay following sequencing of 1.5–2.5% of mutated DNA in a background of wild-type DNA. Assay reproducibility and accuracy were 100%. Application of the HRM assay following sequencing onto genomic DNA isolated from formalin-fixed paraffin-embedded tumour specimens of non-small cell lung cancer (n=91) and colorectal cancer (n=7) patients revealed nucleotide substitutions at codons 12 or 13, including a homozygous mutation, in 33 (34%) and 5 (5%) cases, respectively. Comparison to conventional nested-PCR following cycle-sequencing showed an overall high agreement in genotype findings (kappa value of 0.96), with more mutations detected by the HRM assay following sequencing.Conclusion: HRM allows rapid, reliable and sensitive pre-screening of routine diagnostic specimens for subsequent genotyping of K-ras mutations, even if present at low abundance or homozygosity, and may considerably facilitate personalized therapy planning.

Background: Previous studies demonstrated a functional involvement of the AP-1 transcription factor in HPV-induced cervical carcinogenesis. Here, we aimed to obtain further insight in expression alterations of AP-1 family members during HPV-mediated transformation and their relationship to potential regulatory (Notch1, Net) and target (CADM1) genes.Methods: mRNA expression levels of c-Jun, JunB, junD, c-Fos, FosB, Fra-1, Fra-2, Notch1, Net and CADM1 were determined by quantitative RT-PCR in primary keratinocytes (n=5), early (n=4) and late (n=4) passages of non-tumorigenic HPV-immortalized keratinocytes and in tumorigenic cervical cancer cell lines (n=7). In a subset of cell lines protein expression and AP-1 complex composition was determined.Results: Starting in immortal stages c-Fos, Fra-2 and JunB expression became up regulated towards tumorigenicity, whereas Fra-1, c-Jun, Notch1, Net and CADM1 became down regulated. The onset of deregulated expression varied amongst the AP-1 members and was not directly related to altered Notch1, Net or CADM1 expression. Nevertheless, a shift in AP-1 complex composition from Fra-1/c-Jun to c-Fos/c-Jun heterodimers was only observed in tumorigenic cells.Conclusion: HPV-mediated transformation is associated with altered AP-1, Notch1, Net and CADM1 transcription. Whereas the onset of deregulated expression of various AP-1 family members became already manifest during the immortal state, a shift in AP-1 complex composition appeared a rather late event associated with tumorigenicity.

Recombinant adenoviruses (RAd) and recombinant vaccinia viruses (RVV) expressing tumour-associated antigens (TAA) are used as anti-tumour vaccines. It is important that these vaccines deliver the TAA to dendritic cells (DC) for the induction of a strong immune response. Infection of myeloid DC (MDC) with RAd alone is relatively inefficient but CD40 retargeting significantly increases transduction efficiency and DC maturation. Infection with RVV is efficient without DC maturation. Plasmacytoid dendritic cells (PDC) play a role in the innate immune response to viral infections through the secretion of IFNα but may also play a role in specific T-cell induction. The aim of our study was to investigate whether PDC are better targets for RAd and RVV based vaccines. RAd alone hardly infected PDC (2%) while CD40 retargeting did not improve transduction efficiency, but it did increase PDC maturation (25% CD83 positive cells). Accordingly, specific CTL activation by RAd infected PDC was limited (the number of IFNγ producing CTL was reduced by 75% compared to stimulation with peptide loaded PDC). RVV infected PDC specifically stimulated CTL but PDC were not activated. These Results indicate that PDC are not ideal targets for RAd and RVV based vaccines. However, PDC induced specific CTL activation after pulsing with recombinant protein, indicating that PDC can also cross-present antigens released from surrounding infected cells.