Chemotherapy and zoledronate sensitize solid tumour cells to Vγ9Vδ2 T cell cytotoxicity

Combinations of cellular immune-based therapies with chemotherapy and other antitumour agents may be of significant clinical benefit in the treatment of many forms of cancer. Gamma delta (γδ) T cells are of particular interest for use in such combined therapies due to their potent antitumour cytotoxicity and relative ease of generation in vitro. Here, we demonstrate high levels of cytotoxicity against solid tumour-derived cell lines with combination treatment utilizing Vγ9Vδ2 T cells, chemotherapeutic agents and the bisphosphonate, zoledronate. Pre-treatment with low concentrations of chemotherapeutic agents or zoledronate sensitized tumour cells to rapid killing by Vγ9Vδ2 T cells with levels of cytotoxicity approaching 90%. In addition, zoledronate enhanced the chemotherapy-induced sensitization of tumour cells to Vγ9Vδ2 T cell cytotoxicity resulting in almost 100% lysis of tumour targets in some cases. Vγ9Vδ2 T cell cytotoxicity was mediated by perforin following TCR-dependent and isoprenoid-mediated recognition of tumour cells. Production of IFN-γ by Vγ9Vδ2 T cells was also induced after exposure to sensitized targets. We conclude that administration of Vγ9Vδ2 T cells at suitable intervals after chemotherapy and zoledronate may substantially increase antitumour activities in a range of malignancies.

Diverse populations of T cells with NK cell receptors accumulate in the human intestine in health and in colorectal cancer

T cells expressing NK cell receptors (NKR) display rapid MHC-unrestricted cytotoxicity and potent cytokine secretion and are thought to play roles in immunity against tumors. We have quantified and characterized NKR+ T cells freshly isolated from epithelial and lamina propria layers of duodenum and colon from 16 individuals with no evidence of gastrointestinal disease and from tumor and uninvolved tissue from 19 patients with colorectal cancer. NKR+ T cell subpopulations were differentially distributed in different intestinal compartments, and CD161+ T cells accounted for over one half of T cells at all locations tested. Most intestinal CD161+ T cells expressed alpha beta TCR and either CD4 or CD8. Significant proportions expressed HLA-DR,CD69 and Fas ligand. Upon stimulation in vitro, CD161+ T cells produced IFN-gamma and TNF-alpha but not IL-4. NKT cells expressing the Valpha24Vbeta11 TCR, which recognizes CD1d,were virtually absent from the intestine, but colonic cells produced IFN-gamma in response to the NKT cell agonist ligand alpha-galactosylceramide. NKR+ T cells were not expanded in colonic tumors compared to adjacent uninvolved tissue. The predominance, heterogeneity and differential distribution of NKR+ T cells at different intestinal locations suggests that they are central to intestinal immunity.

Expression of glucose transporter isoforms and the insulin receptor during hamster preimplantation embryo development

During preimplantation development, embryos of many species are known to express up to five isoforms of the facilitative glucose transporter proteins (GLUT). Development of hamster blastocysts is inhibited by glucose. We therefore investigated GLUT isoform and insulin receptor (IR) expression in hamster preimplantation embryos cultured in glucose-free medium from the 8-cell stage onwards. We show that GLUT1, 3 and 8 mRNA are constitutively expressed from the 8-cell to the blastocyst stage. The IR is expressed from the morula stage onwards. Messenger RNA of the insulin-responsive GLUT4 was not detected at any stage. GLUT1 and 3 were localised by immunocytochemistry. GLUT1 was expressed in both embryoblast and trophoblast, in the latter, mainly in basal and lateral membranes directed towards the blastocoel. and embryoblast. GLUT3 was exclusively localised in the apical. membrane of trophoblast cells. We show that hamster preimplantation embryos express several GLUT isoforms thus closely resembling embryos of other mammalian species. Despite endogenous IR expression, the insulin-sensitive isoform GLUT4 was not expressed, indicating that the insulin-mediated glucose uptake known from classical insulin target cells may not be relevant for hamster blastocysts.

Structure and function of GDNF receptor alpha splice variants

The growth factors of the glial cell line-derived neurotrophic factor (GDNF) family consisting of GDNF, neurturin (NRTN), artemin (ARTN) and persephin (PSPN), are involved in the development, differentiation and maintenance of many types of neurons. They also have important functions outside the nervous system in the development of kidney, testis and thyroid gland. Each of these GFLs preferentially binds to one of the glycosylphosphatidylinositol (GPI)-anchored GDNF family receptors α (GFRα). GDNF binds to GFRα1, NRTN to GFRα2, ARTN to GFRα3 and PSPN to GFRα4. The GFLs in the complex with their cognate GFRα receptors all bind to and signal through the receptor tyrosine kinase RET. Alternative splicing of the mouse GFRα4 gene yields three splice isoforms. These had been described as putative GPI-anchored, transmembrane and soluble forms. My goal was to characterise the function of the different forms of mouse GFRα4. I firstly found that the putative GPI-anchored GFRα4 (GFRα4-GPI) is glycosylated, membrane-bound, GPI-anchored and interacts with PSPN and RET. We also showed that mouse GFRα4-GPI mediates PSPN-induced phosphorylation of RET, promotes PSPN-dependent neuronal differentiation of the rat pheochromocytoma cell line PC6-3 and PSPN-dependent survival of cerebellar granule neurons (CGN). However, although this receptor can mediate PSPN-signalling and activate RET, GFRα4-GPI does not recruit RET into lipid rafts. The recruitment of RET into lipid rafts has previously been thought to be a crucial event for GDNF- and GFL-mediated signalling via RET. I secondly demonstrated that the putative transmembrane GFRα4 (GFRα4-TM) is indeed a real transmembrane GFRα4 protein. Although it has a weak binding capacity for PSPN, it can not mediate PSPN-dependent phosphorylation of RET, neuronal differentiation or survival. These data show that GFRα4-TM is inactive as a receptor for PSPN. Surprisingly, GFRα4-TM can negatively regulate PSPN-mediated signalling via GFRα4-GPI. GFRα4-TM interacts with GFRα4-GPI and blocks PSPN-induced phosphorylation of RET, neuronal differentiation as well as survival. Taken together, our data show that GFRα4-TM may act as a dominant negative inhibitor of PSPN-mediated signaling. The most exciting part of my work was the finding that the putative soluble GFRα4 (GFRα4-sol) can form homodimers and function as an agonist of the RET receptor. In the absence of PSPN, GFRα4-sol can promote the phosphorylation of RET, trigger the activation of the PI-3K/AKT pathway, induce neuronal differentiation and support the survival of CGN. Our findings are in line with a recent publication showing the GFRα4-sol might contribute to the inherited cancer syndrome multiple endocrine neoplasia type 2. Our data provide an explanation to how GFRα4-sol may cause or modify the disease. Mammalian GFRα4 receptors all lack the first Cys-rich domain which is present in other GFRα receptors. In the final part of my work I have studied the function of this particular domain. I created a truncated GFRα1 construct lacking the first Cys-rich domain. Using binding assays in both cellular and cell-free systems, phosphorylation assays with RET, as well as neurite outgrowth assays, we found that the first Cys-rich domain contributes to an optimal function of GFRα1, by stabilizing the interaction between GDNF and GFRα1.

Nuclear Import Mechanisms of STAT and NF-kB Transcription Factors

The eukaryotic cell nucleoplasm is separated from the cytoplasm by the nuclear envelope. This compartmentation of eukaryotic cells requires that all nuclear proteins must be transported from the cytoplasm into the nucleus. Transport of macromolecules between the nucleus and the cytoplasm occurs through nuclear pore complexes (NPCs). Proteins to be targeted into the nucleus by the classical nuclear import system contain nuclear localization signals (NLSs), which are recognized by importin alpha, the NLS receptor. Importin alpha binds to importin beta, which docks the importin-cargo complex on the cytoplasmic side of the NPC and mediates the movement of the complex into the nucleus. Presently six human importin alpha isoforms have been identified. Transcription factors are among the most important regulators of gene expression in eukaryotic organisms. Transcription factors bind to specific DNA sequences on target genes and modulate the activity of the target gene. Many transcription factors, including signal transducers and activators of transcription (STAT) and nuclear factor kB (NF-kB), reside in the cytoplasm in an inactive form, and upon activation they are rapidly transported into the nucleus. In the nucleus STATs and NF-kB regulate the activity of genes whose products are critical in controlling numerous cellular and organismal processes, such as inflammatory and immune responses, cell growth, differentiation and survival. The aim of this study was to investigate the nuclear import mechanisms of STAT and NF-kB transcription factors. This work shows that STAT1 homodimers and STAT1/STAT2 heterodimers bind specifically and directly to importin alpha5 molecule via unconventional dimer-specific NLSs. Importin alpha molecules have two regions, which have been shown to directly interact with the amino acids in the NLS of the cargo molecule. The Arm repeats 2-4 comprise the N-terminal NLS binding site and Arm repeats 7-8 the C-terminal NLS binding site. In this work it is shown that the binding site for STAT1 homodimers and STAT1/STAT2 heterodimers is composed of Arm repeats 8 and 9 of importin alpha5 molecule. This work demonstrates that all NF-kB proteins are transported into the nucleus by importin alpha molecules. In addition, NLS was identified in RelB protein. The interactions between NF-kB proteins and importin alpha molecules were found to be directly mediated by the NLSs of NF-kB proteins. Moreover, we found that p50 binds to the N-terminal and p65 to the C-terminal NLS binding site of importin alpha3. The results from this thesis work identify previously uncharacterized mechanisms in nuclear import of STAT and NF-kB. These findings provide new insights into the molecular mechanisms regulating the signalling cascades of these important transcription factors from the cytoplasm into the nucleus to the target genes.

Impeding the adaptive response of prostate cancer to androgen targeted therapies with relaxin receptor antagonist

Androgen deprivation and androgen targeted therapies (ATT) are established treatments for prostate cancer (PCa). Although initially effective, ATT induces an adaptive response that leads to treatment resistance. Increased expression of relaxin-2 (RLN2) is an important alteration in the adaptive response. RLN2 has a well described role in PCa cell proliferation, adhesion and tumour growth. The objectives of this study were to develop cell models for studies of RLN2 signalling and to implement in vitro assays for evaluating the therapeutic properties of the unique RLN2 receptor (RXFP1) antagonist

YB-1, a key regulator of androgen receptor signalling

Reactivation of androgen receptor signalling is one of the hallmarks of prostate cancer progression to the terminal castrate resistant stage. A better understanding of mechanisms driving this adaptive response is essential for the development of innovative intervention strategies that effectively delay or halt prostate cancer progression. The Y-box binding protein 1 (YB-1) has been found to be closely associated with prostate cancer progression. By characterising its role in the adaptive process leading to castrate resistance, we aim to promote YB-1 as a novel therapeutic target in advanced prostate cancer.

Growth factor induction in intervertebral disc tissue: Observations in basic mechanisms of disc degeneration and rearrangement

The intervertebral disc is composed of concentrically arranged components: annulus fibrosus, the transition zone, and central nucleus pulposus. The major disc cell type differs in various parts of the intervertebral disc. In annulus fibrosus a spindle shaped fibroblast-like cell mainly dominates, whereas in central nucleus pulposus the more rounded chondrocyte-like disc cell is the major cell type. At birth the intervertebral disc is well vascularized, but during childhood and adolescence blood vessels become smaller and less numerous. The adult intervertebral disc is avascular and is nourished via the cartilage endplates. On the other hand, degenerated and prolapsed intervertebral discs are again vascularized, and show many changes compared to normal discs, including: nerve ingrowth, change in collagen turnover, and change in water content. Furthermore, the prolapsed intervertebral disc tissue has a tendency to decrease in size over time. Growth factors are polypeptides which regulate cell growth, extracellular matrix protease activity, and vascularization. Oncoproteins c-Fos and c-Jun heterodimerize, forming the AP-1 transcription factor which is expressed in activated cells. In this thesis the differences of growth factor expression in normal intervertebral disc, the degenerated intervertebral disc and herniated intervertebral disc were analyzed. Growth factors of particular interest were basic fibroblast growth factor (bFGF or FGF-2), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and transforming growth factor beta (TGFβ). Cell activation was visualized by the expression of the AP-1 transcription promoters c-Fos and c-Jun. The expression was shown with either mono- or polyclonal antibodies by indirect avidin-biotin-peroxidase immunohistochemical staining method. The normal control material was collected from a tissue bank of five organ donors. The degenerated disc material was from twelve patients operated on for painful degenerative disc disease, and herniated disc tissue material was obtained from 115 patients operated on for sciatica. Normal control discs showed only TGFβ immunopositivity. All other factors studied were immunonegative in the control material. Prolapsed disc material was immunopositive for all factors studied, and this positivity was located either in the disc cells or in blood vessels. Furthermore, neovascularization was noted. Disc cell immunoreaction was shown in chondrocyte-like disc cells or in fibroblast-like disc cells, the former being expressed especially in conglomerates (clusters of disc cells). TGFβ receptor induction was prominent in prolapsed intervertebral disc tissue. In degenerated disc material, the expression of growth factors was analyzed in greater detail in various parts of the disc: nucleus pulposus, anterior annulus fibrosus and posterior annulus fibrosus. PDGF did not show any immunoreactivity, whereas all other studied growth factors were localized either in chondrocyte-like disc cells, often forming clusters, in fibroblast-like disc cells, or in small capillaries. Many of the studied degenerated discs showed tears in the posterior region of annulus fibrosus, but expression of immunopositive growth factors was detected throughout the entire disc. Furthermore, there was a difference in immunopositive cell types for different growth factors. The main conclusion of the thesis, supported by all substudies, is the occurrence of growth factors in disc cells. They may be actively participating in a network regulating disc cell growth, proliferation, extracellular matrix turnover, and neovascularization. Chondrocyte-like disc cells, in particular, expressed growth factors and oncoproteins, highlighting the importance of this cell type in the basic pathophysiologic events involved in disc degeneration and disc rearrangement. The thesis proposes a hypothesis for cellular remodelling in intervertebral disc tissue. In summary, the model presents an activation pattern of different growth factors at different intervertebral disc stages, mechanisms leading to neovascularization of the intervertebral disc in pathological conditions, and alteration of disc cell shape, especially in annulus fibrosus. Chondrocyte-like disc cells become more numerous, and these cells are capable of forming clusters, which appear to be regionally active within the disc. The alteration of the phenotype of disc cells expressing growth factors from fibroblast-like disc cells to chondrocyte-like cells in annulus fibrosus, and the numerous expression of growth factor expressing disc cells in nucleus pulposus, may be a key element both during pathological degeneration of the intervertebral disc, and during the healing process after trauma.

Biology and Molecular Markers of Malignant Gonadal Germ Cell Tumors

Germ cell tumors occur both in the gonads of both sexes and in extra-gonadal sites during adoles-cence and early adulthood. Malignant ovarian germ cell tumors are rare neoplasms accounting for less than 5% of all cases of ovarian malignancy. In contrast, testicular cancer is the most common malignancy among young males. Most of patients survive the disease. Prognostic factors of gonadal germ cell tumors include histology, clinical stage, size of the primary tumor and residua, and levels of tumor markers. Germ cell tumors include heterogeneous histological subgroups. The most common subgroup includes germinomas (ovarian dysgerminoma and testicular seminoma); other subgroups are yolk sac tumors, embryonal carcinomas, immature teratomas and mixed tumors. The origin of germ cell tumors is most likely primordial germ cells. Factors behind germ cell tumor development and differentiation are still poorly known. The purpose of this study was to define novel diagnostic and prognostic factors for malignant gonadal germ cell tumors. In addition, the aim was to shed further light into the molecular mechanisms regulating gonadal germ cell tumorigenesis and differentiation by studying the roles of GATA transcription factors, pluripotent factors Oct-3/4 and AP-2γ, and estrogen receptors. This study revealed the prognostic value of CA-125 in malignant ovarian germ cell tumors. In addition advanced age and residual tumor had more adverse outcome. Several novel markers for histological diagnosis were defined. In the fetal development transcription factor GATA-4 was expressed in early fetal gonocytes and in testicular carcinoma precursor cells. In addition, GATA-4 was expressed in both gonadal germinomas, thus it may play a role in the development and differentiation of the germinoma tumor subtype. Pluripotent factors Oct-3/4 and AP-2γ were expressed in dysgerminomas, thus they could be used in the differential diagnosis of the germ cell tumors. Malignant ovarian germ cell tumors expressed estrogen receptors and their co-regulator SNURF. In addition, estrogen receptor expression was up-regulated by estradiol stimulation. Thus, gonadal steroid hormone burst in puberty may play a role in germ cell tumor development in the ovary. This study shed further light in to the molecular pathology of malignant gonadal germ cell tumors. In addition, some novel diagnostic and prognostic factors were defined. This data may be used in the differential diagnosis of germ cell tumor patients.

Cilengitide combined with cetuximab and platinum-based chemotherapy as first-line treatment in advanced non-small-cell lung cancer (NSCLC) patients: Results of an open-label, randomized, controlled phase II study (CERTO)

Background: This multicentre, open-label, randomized, controlled phase II study evaluated cilengitide in combination with cetuximab and platinum-based chemotherapy, compared with cetuximab and chemotherapy alone, as first-line treatment of patients with advanced non-small-cell lung cancer (NSCLC). Patients and methods: Patients were randomized 1:1:1 to receive cetuximab plus platinum-based chemotherapy alone (control), or combined with cilengitide 2000 mg 1×/week i.v. (CIL-once) or 2×/week i.v. (CIL-twice). A protocol amendment limited enrolment to patients with epidermal growth factor receptor (EGFR) histoscore ≥200 and closed the CIL-twice arm for practical feasibility issues. Primary end point was progression-free survival (PFS; independent read); secondary end points included overall survival (OS), safety, and biomarker analyses. A comparison between the CIL-once and control arms is reported, both for the total cohorts, as well as for patients with EGFR histoscore ≥200. Results: There were 85 patients in the CIL-once group and 84 in the control group. The PFS (independent read) was 6.2 versus 5.0 months for CIL-once versus control [hazard ratio (HR) 0.72; P = 0.085]; for patients with EGFR histoscore ≥200, PFS was 6.8 versus 5.6 months, respectively (HR 0.57; P = 0.0446). Median OS was 13.6 for CIL-once versus 9.7 months for control (HR 0.81; P = 0.265). In patients with EGFR ≥200, OS was 13.2 versus 11.8 months, respectively (HR 0.95; P = 0.855). No major differences in adverse events between CIL-once and control were reported; nausea (59% versus 56%, respectively) and neutropenia (54% versus 46%, respectively) were the most frequent. There was no increased incidence of thromboembolic events or haemorrhage in cilengitide-treated patients. αvβ3 and αvβ5 expression was neither a predictive nor a prognostic indicator. Conclusions: The addition of cilengitide to cetuximab/chemotherapy indicated potential clinical activity, with a trend for PFS difference in the independent-read analysis. However, the observed inconsistencies across end points suggest additional investigations are required to substantiate a potential role of other integrin inhibitors in NSCLC treatment.

Targeting the fibroblast growth factor receptor family in cancer

Fibroblast growth factors (FGFs) regulate a plethora of biological functions, in both the embryonic and adult stages of development, binding their cognate receptors and thus activating a variety of downstream signalling pathways. Deregulation of the FGF/FGFR signalling axis, observed in multifarious tumor types including squamous non-small cell lung cancer, occurs through genomic FGFR alterations that drive ligand-independent receptor signalling or alterations that support ligand-dependent activation. Mutations are not restricted to the tyrosine kinase domain and aberrations appear to be tumor type dependent. As well as its complementarity and synergy with VEGF of particular interest is the interplay between FGFR and EGFR and the ability of these pathways to offer a compensatory signalling escape mechanism when either is inhibited. Hence there exists a rationale for a combinatorial approach to inhibition of these dysregulated pathways to reverse drug resistance. To date, several multi-target tyrosine kinase inhibitors as well as FGFR specific tyrosine kinase inhibitors (TKIs), monoclonal antibodies and FGF ligand traps have been developed. Promising preclinical data has resulted in several drugs entering clinical trials. This review explores aberrant FGFR and its potential as a therapeutic target in solid tumors.

Dacomitinib versus erlotinib in patients with EGFR-mutated advanced nonsmall-cell lung cancer (NSCLC): Pooled subset analyses from two randomized trials

Background: The irreversible epidermal growth factor receptor (EGFR) inhibitors have demonstrated efficacy in NSCLC patients with activating EGFR mutations, but it is unknown if they are superior to the reversible inhibitors. Dacomitinib is an oral, small-molecule irreversible inhibitor of all enzymatically active HER family tyrosine kinases. Methods: The ARCHER 1009 (NCT01360554) and A7471028 (NCT00769067) studies randomized patients with locally advanced/metastatic NSCLC following progression with one or two prior chemotherapy regimens to dacomitinib or erlotinib. EGFR mutation testing was performed centrally on archived tumor samples. We pooled patients with exon 19 deletion and L858R EGFR mutations from both studies to compare the efficacy of dacomitinib to erlotinib. Results: One hundred twenty-one patients with any EGFR mutation were enrolled; 101 had activating mutations in exon 19 or 21. For patients with exon19/21 mutations, the median progression-free survival was 14.6 months [95% confidence interval (CI) 9.0–18.2] with dacomitinib and 9.6 months (95% CI 7.4–12.7) with erlotinib [unstratified hazard ratio (HR) 0.717 (95% CI 0.458–1.124), two-sided log-rank, P = 0.146]. The median survival was 26.6 months (95% CI 21.6–41.5) with dacomitinib versus 23.2 months (95% CI 16.0–31.8) with erlotinib [unstratified HR 0.737 (95% CI 0.431–1.259), two-sided log-rank, P = 0.265]. Dacomitinib was associated with a higher incidence of diarrhea and mucositis in both studies compared with erlotinib. Conclusions: Dacomitinib is an active agent with comparable efficacy to erlotinib in the EGFR mutated patients. The subgroup with exon 19 deletion had favorable outcomes with dacomitinib. An ongoing phase III study will compare dacomitinib to gefitinib in first-line therapy of patients with NSCLC harboring common activating EGFR mutations (ARCHER 1050; NCT01774721). Clinical trials number: ARCHER 1009 (NCT01360554) and A7471028 (NCT00769067).

Transcription of Human Resistin Gene Involves an Interaction of Sp1 with Peroxisome Proliferator-Activating Receptor Gamma (PPAR gamma)

Background: Resistin is a cysteine rich protein, mainly expressed and secreted by circulating human mononuclear cells. While several factors responsible for transcription of mouse resistin gene have been identified, not much is known about the factors responsible for the differential expression of human resistin.Methodology/Principal Finding: We show that the minimal promoter of human resistin lies within similar to 80 bp sequence upstream of the transcriptional start site (-240) whereas binding sites for cRel, CCAAT enhancer binding protein alpha (C/EBP-alpha), activating transcription factor 2 (ATF-2) and activator protein 1 (AP-1) transcription factors, important for induced expression, are present within sequences up to -619. Specificity Protein 1(Sp1) binding site (-276 to -295) is also present and an interaction of Sp1 with peroxisome proliferator activating receptor gamma (PPAR gamma) is necessary for constitutive expression in U937 cells. Indeed co-immunoprecipitation assay demonstrated a direct physical interaction of Sp1 with PPAR gamma in whole cell extracts of U937 cells. Phorbol myristate acetate (PMA) upregulated the expression of resistin mRNA in U937 cells by increasing the recruitment of Sp1, ATF-2 and PPAR gamma on the resistin gene promoter. Furthermore, PMA stimulation of U937 cells resulted in the disruption of Sp1 and PPAR gamma interaction. Chromatin immunoprecipitation (ChIP) assay confirmed the recruitment of transcription factors phospho ATF-2, Sp1, Sp3, PPAR gamma, chromatin modifier histone deacetylase 1 (HDAC1) and the acetylated form of histone H3 but not cRel, C/EBP-alpha and phospho c-Jun during resistingene transcription.Conclusion: Our findings suggest a complex interplay of Sp1 and PPAR gamma along with other transcription factors that drives the expression of resistin in human monocytic U937 cells.