TY  - JOUR
A1  - Kumar, Praveen
A1  - Naumann, Ulrike
A1  - Aigner, Ludwig
A1  - Wischhusen, Joerg
A1  - Beier, Christoph P
A1  - Beier, Dagmar
T1  - Impaired TGF-β induced growth inhibition contributes to the increased proliferation rate of neural stem cells harboring mutant p53
JF  - American Journal of Cancer Research
N2  - Gliomas have been classified according to their histological properties. However, their respective cells of origin are still unknown. Neural progenitor cells (NPC) from the subventricular zone (SVZ) can initiate tumors in murine models of glioma and are likely cells of origin in the human disease. In both, p53 signaling is often functionally impaired which may contribute to tumor formation. Also, TGF-beta, which under physiological conditions exerts a strong control on the proliferation of NPCs in the SVZ, is a potent mitogen on glioma cells. Here, we approach on the crosstalk between p53 and TGF-beta by loss of function experiments using NPCs derived from p53 mutant mice, as well as pharmacological inhibition of TGF-beta signaling using TGF-beta receptor inhibitors. NPC derived from p53 mutant mice showed increased clonogenicity and more rapid proliferation than their wildtype counterparts. Further, NPC derived from p53\(^{mut/mut}\) mice were insensitive to TGF-beta induced growth arrest. Still, the canonical TGF-beta signaling pathway remained functional in the absence of p53 signaling and expression of key proteins as well as phosphorylation and nuclear translocation of SMAD2 were unaltered. TGF-beta-induced p21 expression could, in contrast, only be detected in p53\(^{wt/wt}\) but not in p53\(^{mut/mut}\) NPC. Conversely, inhibition of TGF-beta signaling using SB431542 increased proliferation of p53\(^{wt/wt}\) but not of p53\(^{mut/mut}\) NPC. In conclusion, our data suggest that the TGF-beta induced growth arrest in NPC depends on functional p53. Mutational inactivation of p53 hence contributes to increased proliferation of NPC and likely to the formation of hyperplasia of the SVZ observed in p53 deficient mice in vivo.
KW  - mouse brain
KW  - tumors
KW  - cancer
KW  - TGF-beta
KW  - glioblastoma stem cell
KW  - pathways
KW  - expression
KW  - astrocytoma
KW  - glioblastoma
KW  - transforming growth factor-beta-1
KW  - neurogenesis
KW  - gliomas
KW  - neural stem cell
KW  - p53
KW  - subventricular zone
KW  - premalignant lesion
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-144262
VL  - 5
IS  - 11
ER  - 
TY  - JOUR
A1  - Klement, Rainer
A1  - Kämmerer, Ulrike
T1  - Is there a role for carbohydrate restriction in the treatment and prevention of cancer?
N2  - Over the last years, evidence has accumulated suggesting that by systematically reducing the amount of dietary carbohydrates (CHOs) one could suppress, or at least delay, the emergence of cancer, and that proliferation of already existing tumor cells could be slowed down. This hypothesis is supported by the association between modern chronic diseases like the metabolic syndrome and the risk of developing or dying from cancer. CHOs or glucose, to which more complex carbohydrates are ultimately digested, can have direct and indirect effects on tumor cell proliferation: first, contrary to normal cells, most malignant cells depend on steady glucose availability in the blood for their energy and biomass generating demands and are not able to metabolize significant amounts of fatty acids or ketone bodies due to mitochondrial dysfunction. Second, high insulin and insulin-like growth factor (IGF)-1 levels resulting from chronic ingestion of CHO-rich Western diet meals, can directly promote tumor cell proliferation via the insulin/IGF1 signaling pathway. Third, ketone bodies that are elevated when insulin and blood glucose levels are low, have been found to negatively affect proliferation of different malignant cells in vitro or not to be usable by tumor cells for metabolic demands, and a multitude of mouse models have shown antitumorigenic properties of very low CHO ketogenic diets. In addition, many cancer patients exhibit an altered glucose metabolism characterized by insulin resistance and may profit from an increased protein and fat intake. In this review, we address the possible beneficial effects of low CHO diets on cancer prevention and treatment. Emphasis will be placed on the role of insulin and IGF1 signaling in tumorigenesis as well as altered dietary needs of cancer patients.
KW  - Medizin
KW  - Ketogenic diet
KW  - cancer
KW  - review
KW  - low carbohydrate diet
KW  - cachexia
KW  - insulin
KW  - insulin-like growth factor 1 (IGF1)
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69178
ER  -