@article{MoenchGrimmigKannenetal.2016, author = {Moench, Romana and Grimmig, Tanja and Kannen, Vinicius and Tripathi, Sudipta and Faber, Marc and Moll, Eva-Maria and Chandraker, Anil and Lissner, Reinhard and Germer, Christoph-Thomas and Waaga-Gasser, Ana Maria and Gasser, Martin}, title = {Exclusive inhibition of PI3K/Akt/mTOR signaling is not sufficient to prevent PDGF-mediated effects on glycolysis and proliferation in colorectal cancer}, series = {Oncotarget}, volume = {7}, journal = {Oncotarget}, number = {42}, doi = {10.18632/oncotarget.11899}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176910}, pages = {68749-68767}, year = {2016}, abstract = {Platelet-derived growth factor (PDGF) and signaling via its receptors plays a crucial role in tumor cell proliferation and thus may represent an attractive target besides VEGF/EGFR-based antibody therapies. In this study we analyzed the influence of PDGF in colorectal cancer. PDGF was expressed intensively in early and even more intensively in late stage primary CRCs. Like VEGF, PDGF enhanced human colon cancer proliferation, and increased oxidative glycolytic activity, and activated HIF1α and c-Myc in vitro. PDGF activated the PI3K/Akt/mTOR pathway while leaving MAPK signaling untouched. Further dissection showed that inhibition of Akt strongly impeded cancer cell growth while inhibition of PI3K did not. MAPK analysis suggested an inhibitory crosstalk between both pathways, thus explaining the different effects of the Akt and PI3K inhibitors on cancer cell proliferation. PDGF stimulates colon cancer cell proliferation, and prevents inhibitor induced apoptosis, resulting in tumor growth. Therefore inhibition of PDGF signaling seems to be a promising target in colorectal cancer therapy. However, due to the multifaceted nature of the intracellular PDGF signaling, careful intervention strategies are needed when looking into specific signaling pathways like PI3K/Akt/mTOR and MAPK.}, language = {en} } @article{KannenHintzscheZanetteetal.2012, author = {Kannen, Vinicius and Hintzsche, Henning and Zanette, Dalila L. and Silva Jr., Wilson A. and Garcia, Sergio B. and Waaga-Gasser, Anna Maria and Stopper, Helga}, title = {Antiproliferative Effects of Fluoxetine on Colon Cancer Cells and in a Colonic Carcinogen Mouse Model}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-75879}, year = {2012}, abstract = {The antidepressant fluoxetine has been under discussion because of its potential influence on cancer risk. It was found to inhibit the development of carcinogen-induced preneoplastic lesions in colon tissue, but the mechanisms of action are not well understood. Therefore, we investigated anti-proliferative effects, and used HT29 colon tumor cells in vitro, as well as C57BL/6 mice exposed to intra-rectal treatment with the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) as models. Fluoxetine increased the percentage of HT29 cells in the G0/G1 phase of cell-cycle, and the expression of p27 protein. This was not related to an induction of apoptosis, reactive oxygen species or DNA damage. In vivo, fluoxetine reduced the development of MNNG-induced dysplasia and vascularization-related dysplasia in colon tissue, which was analyzed by histopathological techniques. An anti-proliferative potential of fluoxetine was observed in epithelial and stromal areas. It was accompanied by a reduction of VEGF expression and of the number of cells with angiogenic potential, such as CD133, CD34, and CD31-positive cell clusters. Taken together, our findings suggest that fluoxetine treatment targets steps of early colon carcinogenesis. This confirms its protective potential, explaining at least partially the lower colon cancer risk under antidepressant therapy.}, subject = {Medizin}, language = {en} }