Showing papers on "Cancer research published in 2013"

Mast Cells Are Dispensable for Normal and Activin-Promoted Wound Healing and Skin Carcinogenesis

Abstract: The growth and differentiation factor activin A is a key regulator of tissue repair, inflammation, fibrosis, and tumorigenesis. However, the cellular targets, which mediate the different activin functions, are still largely unknown. In this study, we show that activin increases the number of mature mast cells in mouse skin in vivo. To determine the relevance of this finding for wound healing and skin carcinogenesis, we mated activin transgenic mice with CreMaster mice, which are characterized by Cre recombinase-mediated mast cell eradication. Using single- and double-mutant mice, we show that loss of mast cells neither affected the stimulatory effect of overexpressed activin on granulation tissue formation and reepithelialization of skin wounds nor its protumorigenic activity in a model of chemically induced skin carcinogenesis. Furthermore, mast cell deficiency did not alter wounding-induced inflammation and new tissue formation or chemically induced angiogenesis and tumorigenesis in mice with normal activin levels. These findings reveal that mast cells are not major targets of activin during wound healing and skin cancer development and also argue against nonredundant functions of mast cells in wound healing and skin carcinogenesis in general.

Phosphotyrosine Profiling of NSCLC Cells in Response to EGF and HGF Reveals Network Specific Mediators of Invasion

Abstract: Growth factor signaling is deregulated in cancer and often leads to invasion, yet receptor tyrosine kinase signaling pathways driving invasion under different growth factor conditions are not well understood. To identify specific signaling molecules regulating invasion of A549 non-small cell lung carcinoma (NSCLC) cells downstream of the epidermal growth factor receptor (EGFR) and Met, quantitative site specific mass spectrometric analysis of tyrosine phosphorylation was performed following epidermal growth factor (EGF) or hepatocyte growth factor (HGF) stimulation, at three different growth factor concentrations and at two time points. Through this analysis the temporal and concentration dependent phosphorylation profiles were obtained for 131 sites and 139 sites downstream of EGF and HGF stimulation, respectively. To characterize the effect of these signaling network alterations, we quantified 3D cell migration/invasion through Matrigel. Partial least squares regression (PLSR) analysis was performed to identify the tyrosine phosphorylation sites most strongly correlated with EGF and/or HGF mediated invasion. Potential common and specific signaling events required for driving invasion downstream of EGFR and Met were identified using either a combined or two independent PLSR models, based on the quantitative EGF or HGF data. Our data highlight the integration and compartmentalization of signaling required for invasion in cancer.

I-labeled vascular endothelial growth factor receptor2 (VEGFR2)-resistant chimeric Fab and use thereof

Abstract: The invention discloses a I-labeled vascular endothelial growth factor receptor2 (VEGFR2)-resistant chimeric Fab and a use thereof The I-labeled VEGFR2-resistant chimeric Fab is prepared by a chloramines-T oxidation technology The preparation method of the I-labeled VEGFR2-resistant chimeric Fab comprises of labeling VEGFR2-resistant chimeric Fab by I, carrying out separation purification of I-FA8H1, and determining radiochemical purity and specific activity The I-labeled VEGFR2-resistant chimeric Fab is suitable for radionuclide image-based liver cancer diagnosis The I-FA8H1 is used for targeted treatment on liver cancer, can effectively inhibit cancer growth, has effects obviously superior to effects of single FA8H1 or I, can promote large-area necrosis of cancer tissue, can induce liver cell apoptosis, and does not inhibit peripheral blood wbc for a long time thereby preventing the side effect of reducing immunity Therefore, the I-labeled VEGFR2-resistant chimeric Fab can be used for preparation of a drug for treating liver cancer

Analyse zur Rolle von pflanzlichen Wirkstoffen und Histondeacetylase-Inhibitoren auf Wachstumsfaktoren und deren Signalwege in Prostatakarzinomzellen

Abstract: Prostate cancer (PCa) is the most frequently new diagnosed cancer entity and the third leading cause of cancer-related deaths of men in Germany. The options for therapy of PCa are restricted and most of them have strong side-effects. Therefore, new strategies for the therapy of PCa have been followed up in this thesis: the phytoestrogen tectorigenin as well as the histone deacetylase inhibitor valproic acid (VPA) have been investigated for their efficiency against PCa. The phytoestrogen tectorigenin is isolated from the full extract of the rhizome of Belamcanda chinensis. At first, this full extract has been tested in vitro. Both in the human PCa cell line LNCaP and the murine PCa cell line 2E, which was derived from the prostate tumour of a TRAMP-(transgenic adenocarcinoma of mouse prostate) mouse, cell proliferation was diminished and the expression of PCa-related genes was changed after the treatment. Subsequently, a microarray analysis was performed after the treatment of the human LNCaP cells with tectorigenin and several genes were detected as differentially expressed. Besides from a couple of androgen-inducible genes, the differential expression of the IGF-IR (insulin-like growth factor I receptor) and PSA (prostate specific antigen) were detected. In vivo studies in TRAMP-mice revealed a decelerated progression of the PCa after the treatment with tectorigenin. In in vivo studies on subcutaneously injected LNCaP-tumours in nude mice, a diminished tumour volume as well as a reduced tumour weight was monitored after the treatment with tectorigenin. In the second part of this thesis, the effect of VPA on PCa cells was investigated. Functionally, a higher acetylation of histone 3 at lysine 9 as well as diminished cell proliferation, invasion and migration was shown in the primary PCa cells 2E after the treatment with VPA. On the molecular level, several differentially expressed genes were detected after VPA treatment of 2E cells, e.g. a decreased androgen receptor expression, an increase in expression of the proapototic protein Bim as well as a diminished expression of Foxo1 and Gsk3β. Additionally, a deregulation of important factors for cell cycle progression and angiogenesis was shown, for example for Cdkn1a, Cdk4, Vegfa und Hif1α. Furthermore, candidate genes of a former microarray analysis were included in the examinations. For all seven candidate genes the differential expression was confirmed in a time and dose-dependent manner using quantitative real time PCR after the treatment of 2E-PCa cells with VPA. For the genes with an increased expression, a connection to increased acetylation in the promoter region after the treatment of 2E cells with VPA could be confirmed. The candidate gene cyclin D2 was chosen for further analyses. Cyclin D2 was the only member of the D-type cyclins that showed an increased expression after the treatment with VPA. This re-expression was also induced by histone deacetylase inhibitors of different classes. The analysis of other PCa cell lines (PC-3, DU145 and LNCaP) also showed, comparable to the effects in PCa cells 2E, an increase in cyclin D2 expression and an inhibition of proliferation after the treatment with VPA. Non-malignant cell lines, which already express cyclin D2 at high levels, did not change their cyclin D2 expression after the treatment with VPA and the effect on proliferation was only moderate. The decrease of cyclin D2 expression via siRNA caused an increase in proliferation. The fact that cyclin D2 is a tumour suppressor in PCa was also confirmed by immunohistochemical analysis of human PCa tissue, i.e. it was shown that cyclin D2 is not expressed in PCa tissue, whereas in healthy tissue of the prostate cyclin D2 was expressed in proliferating cells. In contrast, cyclin D1 showed a stronger expression in PCa tissue compared to healthy tissue of the prostate. Finally, in vivo studies in TRAMP-mice were performed by feeding VPA through the drinking water. Three different groups were investigated: a) In the survival group, where the mice were fed with VPA from six weeks of age, an increased survival was observed. Additionally, fewer mice with a prostate tumour and a lower tumour weight were detected. b) The preventive administration of VPA from six weeks to the age of 30 weeks did not show any differences as compared to the control group. c) In the therapeutical survival group, where the mice were fed with VPA from the age of 16 weeks on, a higher age of survival and fewer mice with a prostate tumour were detected, the tumour weight was comparable to control-treated mice.

Die Rolle der IGF-Achse in Kombination mit anderen Wachstumsfaktor-Signalwegen bei der Resistenz oder dem Ansprechen von kolorektalen Karzinomen auf eine Radiochemotherapie

Abstract: In the Western world cancer represents one of the major health problems. Colorectal cancer (CRC) is the third most common tumor incidence. In advanced disease, in most cases a combined radiochemotherapy (RCT) is performed, where cytostatics such as 5-fluorouracil or oxaliplatin are administered in addition to irradiation. Because the cytotoxic drugs used act not only against tumor cells, the use of these drugs often cause severe side effects such as stomach and intestinal problems, myelosuppression and alopecia. Therefore, new therapeutic approaches try to find new treatment goals that are more cancer cell-specific, such as the inhibition of different receptor tyrosine kinases. In the tumor and surrounding tissues many receptor tyrosine kinases and their ligands are often deregulated and play an important role in the regulation of tumor growth, tumor angiogenesis and metastasis. In this work it was demonstrated in vitro for the three colorectal carcinoma cell lines DLD-1, SW837 and Caco2 that the concomitant inhibition of the Insulin-like Growth Factor-I Receptor (IGF-IR) and the Epidermal Growth Factor Receptor (EGFR) with the tyrosine kinase inhibitors AEW-541 (IGF-IR inhibitor) and erlotinib (EGFR inhibitor) leads to a significantly enhanced therapeutic effect of the 5-fluorouracil based RCT. This effect could also be confirmed in vivo by using xenograft tumors of the cell line SW837. In the CRC cell lines SW480 and DLD-1 we were able to detecthybrid receptors between the IGF-IR and the EGFR by using both co-immunoprecipitation and proximity ligation assays. In addition, it was shown that a stimulation of the receptors by their ligands leads to increased EGFR/IGF-IR hybrid receptor formations. Further analysis showed that both receptor ligands are necessary for the induced heterodimerization and both receptors have to be functional. By using the proximity ligation assay EGFR/IGF-IR hybrid receptors were also detected in situ in human rectal tumor specimens. In the last part of the present work, the significance of the Platelet-derived Growth Factor Receptor β (PDGFR-β) was studied in CRC cells. In SW480 and DLD-1 cells, inhibition of PDGFR-β using specific siRNAs moderately reduced the proliferation rate via a decreased activity of the PI3K signaling pathway. The treatment of these CRC cell lines with the PDGFR-β inhibitor Ki11502 led to a strong decrease in the proliferation rate and to changes in the cell cycle which was caused by a decreased expression of Cyclin-B1. Further analyses showed that the inhibitor Ki11502, in addition to the blockade of the PDGFR-β, inhibited the ckit receptor (v -kit Hardy - Zuckerman 4 feline sarcoma viral oncogene homolog) and the cell membrane associated cytoplasmic tyrosine kinase SRC (V -src sarcoma (Schmidt -Ruppin A-2) viral oncogene homolog) in CRC cells.

The Role of the Hedgehog Receptor Patched in LysM+ Cells in Mice

Abstract: Cancer development is frequently linked to signaling pathways that are required for normal embryonic patterning. One of the pathways important in patterning and growth of the embryo is the Hedgehog (Hh) signaling cascade. Activation or inappropriate maintenance of this pathway in the adult organism is frequently caused by mutations in the Hh receptor Patched (Ptch) or overexpression of Hh and can result in the development of a variety of tumors. Whereas the pathway’s function in tissues such as skin, brain, lung, muscle, bladder, breast and prostate is well studied, the knowledge about its role and tumorigenic potential in cells composing the immune system is very limited. The original goal of this thesis was to elucidate the function of Ptch in macrophages. For this purpose Ptchflox/flox mice were crossed with LysMcre mice. The latter mice express a cre recombinase specifically in lysozyme M (LysM) positive cells that are mainly macrophages, granulocytes and dendritic cells (DC), which are derived from the myeloid lineage. Surprisingly, the Ptch mutation in LysM positive cells resulted in multiple tumors arising from the wall of the stomach or the intestine. In the tumors Hh signaling was activated. Furthermore the histology, localization, responsiveness to imatinib, and molecular analysis were suggestive of Gastrointestinal Stromal Tumors (GIST). Because human GIST are considered to arise from KIT- or PDGFRA-expressing cells of the smooth muscle layer of the GI tract, this observation was inconsistent with the Ptch mutation in the myeloid lineage. To resolve this discrepancy, a lineage tracing experiment was performed. The data showed that the tumors indeed arose from LysM-expressing cells. In addition, these cells were Kit-negative and sometimes expressed Pdgfrα. Similar relationships of Kit and Pdgfrα expression were found in the GIST-like tumors, which were all negative for Kit, but highly expressed Pdgfrα. Since HH- and PDGFRA, but not KIT-signaling pathways cooperated in oncogenic transformation, the data suggest that the GIST-like tumors in Ptch mutant mice developed due to the cooperativity between Hh and Pdgfrα pathways from Kit-negative cells in the intestine. In addition, the function of Ptch-deficient macrophages was analyzed. First, the response to inflammatory stimuli was investigated. For this purpose, bone-marrow derived macrophages (BMDM) were isolated from Ptchflox/floxLysMcre+/- animals and were challenged with lipopolysaccharide (LPS) or bacterial lipoprotein (BLP). The preliminary analyses showed that Ptch was important for IL-6 expression and macrophage proliferation after BLP stimulation. Second, in order to study the role of Ptch-deficient macrophages (and other myeloid cells) in tumor immune surveillance, tumors (other than GIST) were induced in Ptchflox/floxLysMcre+/- mice. In a first approach, syngeneic melanoma cells were injected i.p. or i.v. into Ptchflox/floxLysMcre+/- and respective control mice. The analysis revealed that the Ptch-deficiency had no impact on primary or metastatic tumor growth. Similar observations were made after i.p. injection of the slow-growing ovarian carcinoma cell line ID8-LUC and monitoring of tumor growth by chemoluminescence. Finally, Ptchflox/floxLysMcre+/- and control mice were subjected to the two-stage chemical carcinogenesis DMBA/TPA protocol, which results in the development of papilloma and melanoma-like nevi. Whereas papilloma growth was not affected by the Ptch mutation, the nevi growth was significantly enhanced in Ptchflox/floxLysMcre+/- animals which were associated with a stronger infiltration with skin macrophages. Taken together, these results suggest that Ptch-deficiency in LysM-expressing cells such as macrophages modulates inflammatory responses and may promote growth of melanoma.

R-CHOP-21 Remains the Standard for Diffuse Large B-Cell Lymphoma

Abstract: Increasing the dose intensity of chemotherapy for newly diagnosed diffuse large B-cell lymphoma (DLBCL) has been proposed as a means to improve