Cathepsin D Protects Human Neuroblastoma Cells from Doxorubicin-Induced Cell Death.

@article{citeulike:2915518, abstract = {High incidence of chemotherapy resistance is the primary cause of treatment failure in a subset of neuroblastomas with amplified MYCN. We have previously reported that ectopic MYCN expression promotes proliferation of neuroblastoma Tet21N cells, and simultaneously sensitizes them to the drug-induced apoptosis. In search for genes that are involved in MYCN-dependent regulation of drug resistance, we used a function-based gene cloning approach, and identified CTSD, encoding for a lysosomal aspartyl protease cathepsin D. Downregulation of cathepsin D expression by RNA-interference or inhibition of its enzymatic activity increased sensitivity of MYCN-expressing Tet21N cells to doxorubicin. Overexpression of cathepsin D in Tet21N cells attenuated doxorubicin-induced apoptosis. It was accompanied by activation of Akt and persistent anti-apoptotic activity of Bcl-2. In primary neuroblastomas, high CTSD mRNA levels were associated with amplified MYCN, a strong predictive marker of adverse outcome. Chromatin immunoprecipitation (ChIP) and luciferase promoter assays revealed that MYCN protein binds to the CTSD promoter and activates its transcription, suggesting a direct link between deregulated MYCN and CTSD mRNA expression. We further show that neuroblastoma cells can secrete mitogenic procathepsin D, and that MYCN expression and especially doxorubicin treatment promote procathepsin D secretion. Extracellular exogenous cathepsin D induces Akt-1 phosphorylation and doxorubicin resistance in sensitive cells. These results demonstrate an important role of cathepsin D in antiapoptotic signaling in neuroblastoma cells and suggest a novel mechanism for the development of chemotherapy resistance in neuroblastoma.}, address = {Department of Tumor Genetics B030, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.}, author = {Sagulenko, Vitalia and Muth, Daniel and Sagulenko, Evgeny and Paffhausen, Tobias and Schwab, Manfred and Westermann, Frank }, citeulike-article-id = {2915518}, issn = {1460-2180}, journal = {Carcinogenesis}, keywords = {chip, ctsd, doxorubicin, mycn, neuroblastoma}, month = {June}, posted-at = {2008-06-22 21:30:32}, priority = {2}, title = {Cathepsin D Protects Human Neuroblastoma Cells from Doxorubicin-Induced Cell Death.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/18566016}, year = {2008} }

TY - JOUR ID - citeulike:2915518 L3 - citeulike-article-id:2915518 N2 - High incidence of chemotherapy resistance is the primary cause of treatment failure in a subset of neuroblastomas with amplified MYCN. We have previously reported that ectopic MYCN expression promotes proliferation of neuroblastoma Tet21N cells, and simultaneously sensitizes them to the drug-induced apoptosis. In search for genes that are involved in MYCN-dependent regulation of drug resistance, we used a function-based gene cloning approach, and identified CTSD, encoding for a lysosomal aspartyl protease cathepsin D. Downregulation of cathepsin D expression by RNA-interference or inhibition of its enzymatic activity increased sensitivity of MYCN-expressing Tet21N cells to doxorubicin. Overexpression of cathepsin D in Tet21N cells attenuated doxorubicin-induced apoptosis. It was accompanied by activation of Akt and persistent anti-apoptotic activity of Bcl-2. In primary neuroblastomas, high CTSD mRNA levels were associated with amplified MYCN, a strong predictive marker of adverse outcome. Chromatin immunoprecipitation (ChIP) and luciferase promoter assays revealed that MYCN protein binds to the CTSD promoter and activates its transcription, suggesting a direct link between deregulated MYCN and CTSD mRNA expression. We further show that neuroblastoma cells can secrete mitogenic procathepsin D, and that MYCN expression and especially doxorubicin treatment promote procathepsin D secretion. Extracellular exogenous cathepsin D induces Akt-1 phosphorylation and doxorubicin resistance in sensitive cells. These results demonstrate an important role of cathepsin D in antiapoptotic signaling in neuroblastoma cells and suggest a novel mechanism for the development of chemotherapy resistance in neuroblastoma. JF - Carcinogenesis SN - 1460-2180 AD - Department of Tumor Genetics B030, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany. TI - Cathepsin D Protects Human Neuroblastoma Cells from Doxorubicin-Induced Cell Death. KW - chip KW - ctsd KW - doxorubicin KW - mycn KW - neuroblastoma AU - Sagulenko, Vitalia AU - Muth, Daniel AU - Sagulenko, Evgeny AU - Paffhausen, Tobias AU - Schwab, Manfred AU - Westermann, Frank PY - 2008/06/19/ UR - http://view.ncbi.nlm.nih.gov/pubmed/18566016 ER -