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  • 1
    Publication Date: 2012-01-28
    Description: Inhibition of the BRAF(V600E) oncoprotein by the small-molecule drug PLX4032 (vemurafenib) is highly effective in the treatment of melanoma. However, colon cancer patients harbouring the same BRAF(V600E) oncogenic lesion have poor prognosis and show only a very limited response to this drug. To investigate the cause of the limited therapeutic effect of PLX4032 in BRAF(V600E) mutant colon tumours, here we performed an RNA-interference-based genetic screen in human cells to search for kinases whose knockdown synergizes with BRAF(V600E) inhibition. We report that blockade of the epidermal growth factor receptor (EGFR) shows strong synergy with BRAF(V600E) inhibition. We find in multiple BRAF(V600E) mutant colon cancers that inhibition of EGFR by the antibody drug cetuximab or the small-molecule drugs gefitinib or erlotinib is strongly synergistic with BRAF(V600E) inhibition, both in vitro and in vivo. Mechanistically, we find that BRAF(V600E) inhibition causes a rapid feedback activation of EGFR, which supports continued proliferation in the presence of BRAF(V600E) inhibition. Melanoma cells express low levels of EGFR and are therefore not subject to this feedback activation. Consistent with this, we find that ectopic expression of EGFR in melanoma cells is sufficient to cause resistance to PLX4032. Our data suggest that BRAF(V600E) mutant colon cancers (approximately 8-10% of all colon cancers), for which there are currently no targeted treatment options available, might benefit from combination therapy consisting of BRAF and EGFR inhibitors.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Prahallad, Anirudh -- Sun, Chong -- Huang, Sidong -- Di Nicolantonio, Federica -- Salazar, Ramon -- Zecchin, Davide -- Beijersbergen, Roderick L -- Bardelli, Alberto -- Bernards, Rene -- England -- Nature. 2012 Jan 26;483(7387):100-3. doi: 10.1038/nature10868.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Molecular Carcinogenesis, Center for Biomedical Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22281684" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies, Monoclonal/pharmacology ; Antibodies, Monoclonal, Humanized ; Antineoplastic Agents/pharmacology/therapeutic use ; Apoptosis/drug effects ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Cetuximab ; Colorectal Neoplasms/*drug therapy/*enzymology/genetics/pathology ; Drug Resistance, Neoplasm/*drug effects ; Drug Synergism ; Enzyme Activation/drug effects ; Erlotinib Hydrochloride ; Feedback, Physiological/*drug effects ; Female ; HEK293 Cells ; Humans ; Indoles/pharmacology/therapeutic use ; Melanoma/drug therapy/metabolism ; Mice ; Protein Kinase Inhibitors/pharmacology/therapeutic use ; Proto-Oncogene Proteins B-raf/*antagonists & ; inhibitors/chemistry/*genetics/metabolism ; Quinazolines/pharmacology/therapeutic use ; RNA Interference ; Receptor, Epidermal Growth Factor/*agonists/antagonists & inhibitors/metabolism ; Sulfonamides/pharmacology/therapeutic use ; Xenograft Model Antitumor Assays
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2012-06-23
    Description: A main limitation of therapies that selectively target kinase signalling pathways is the emergence of secondary drug resistance. Cetuximab, a monoclonal antibody that binds the extracellular domain of epidermal growth factor receptor (EGFR), is effective in a subset of KRAS wild-type metastatic colorectal cancers. After an initial response, secondary resistance invariably ensues, thereby limiting the clinical benefit of this drug. The molecular bases of secondary resistance to cetuximab in colorectal cancer are poorly understood. Here we show that molecular alterations (in most instances point mutations) of KRAS are causally associated with the onset of acquired resistance to anti-EGFR treatment in colorectal cancers. Expression of mutant KRAS under the control of its endogenous gene promoter was sufficient to confer cetuximab resistance, but resistant cells remained sensitive to combinatorial inhibition of EGFR and mitogen-activated protein-kinase kinase (MEK). Analysis of metastases from patients who developed resistance to cetuximab or panitumumab showed the emergence of KRAS amplification in one sample and acquisition of secondary KRAS mutations in 60% (6 out of 10) of the cases. KRAS mutant alleles were detectable in the blood of cetuximab-treated patients as early as 10 months before radiographic documentation of disease progression. In summary, the results identify KRAS mutations as frequent drivers of acquired resistance to cetuximab in colorectal cancers, indicate that the emergence of KRAS mutant clones can be detected non-invasively months before radiographic progression and suggest early initiation of a MEK inhibitor as a rational strategy for delaying or reversing drug resistance.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3927413/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3927413/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Misale, Sandra -- Yaeger, Rona -- Hobor, Sebastijan -- Scala, Elisa -- Janakiraman, Manickam -- Liska, David -- Valtorta, Emanuele -- Schiavo, Roberta -- Buscarino, Michela -- Siravegna, Giulia -- Bencardino, Katia -- Cercek, Andrea -- Chen, Chin-Tung -- Veronese, Silvio -- Zanon, Carlo -- Sartore-Bianchi, Andrea -- Gambacorta, Marcello -- Gallicchio, Margherita -- Vakiani, Efsevia -- Boscaro, Valentina -- Medico, Enzo -- Weiser, Martin -- Siena, Salvatore -- Di Nicolantonio, Federica -- Solit, David -- Bardelli, Alberto -- P30 CA008748/CA/NCI NIH HHS/ -- R01 CA127240/CA/NCI NIH HHS/ -- T32 CA009207/CA/NCI NIH HHS/ -- England -- Nature. 2012 Jun 28;486(7404):532-6. doi: 10.1038/nature11156.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Genetics, Institute for Cancer Research and Treatment, 10060 Candiolo (Torino), Italy.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22722830" target="_blank"〉PubMed〈/a〉
    Keywords: Alleles ; Antibodies, Monoclonal/*pharmacology/therapeutic use ; Antibodies, Monoclonal, Humanized ; Cell Line, Tumor ; Cetuximab ; Colorectal Neoplasms/*drug therapy/*genetics/pathology ; Disease Progression ; Drug Resistance, Neoplasm/*drug effects/genetics ; Genes, ras/genetics ; Humans ; Mitogen-Activated Protein Kinase Kinases/antagonists & inhibitors ; Mutation/*genetics ; Promoter Regions, Genetic/genetics ; Proto-Oncogene Proteins/*genetics ; Receptor, Epidermal Growth Factor/*antagonists & inhibitors ; ras Proteins/*genetics
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2014-03-29
    Description: Treatment of BRAF(V600E) mutant melanoma by small molecule drugs that target the BRAF or MEK kinases can be effective, but resistance develops invariably. In contrast, colon cancers that harbour the same BRAF(V600E) mutation are intrinsically resistant to BRAF inhibitors, due to feedback activation of the epidermal growth factor receptor (EGFR). Here we show that 6 out of 16 melanoma tumours analysed acquired EGFR expression after the development of resistance to BRAF or MEK inhibitors. Using a chromatin-regulator-focused short hairpin RNA (shRNA) library, we find that suppression of sex determining region Y-box 10 (SOX10) in melanoma causes activation of TGF-beta signalling, thus leading to upregulation of EGFR and platelet-derived growth factor receptor-beta (PDGFRB), which confer resistance to BRAF and MEK inhibitors. Expression of EGFR in melanoma or treatment with TGF-beta results in a slow-growth phenotype with cells displaying hallmarks of oncogene-induced senescence. However, EGFR expression or exposure to TGF-beta becomes beneficial for proliferation in the presence of BRAF or MEK inhibitors. In a heterogeneous population of melanoma cells having varying levels of SOX10 suppression, cells with low SOX10 and consequently high EGFR expression are rapidly enriched in the presence of drug, but this is reversed when the drug treatment is discontinued. We find evidence for SOX10 loss and/or activation of TGF-beta signalling in 4 of the 6 EGFR-positive drug-resistant melanoma patient samples. Our findings provide a rationale for why some BRAF or MEK inhibitor-resistant melanoma patients may regain sensitivity to these drugs after a 'drug holiday' and identify patients with EGFR-positive melanoma as a group that may benefit from re-treatment after a drug holiday.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sun, Chong -- Wang, Liqin -- Huang, Sidong -- Heynen, Guus J J E -- Prahallad, Anirudh -- Robert, Caroline -- Haanen, John -- Blank, Christian -- Wesseling, Jelle -- Willems, Stefan M -- Zecchin, Davide -- Hobor, Sebastijan -- Bajpe, Prashanth K -- Lieftink, Cor -- Mateus, Christina -- Vagner, Stephan -- Grernrum, Wipawadee -- Hofland, Ingrid -- Schlicker, Andreas -- Wessels, Lodewyk F A -- Beijersbergen, Roderick L -- Bardelli, Alberto -- Di Nicolantonio, Federica -- Eggermont, Alexander M M -- Bernards, Rene -- MOP-130540/Canadian Institutes of Health Research/Canada -- England -- Nature. 2014 Apr 3;508(7494):118-22. doi: 10.1038/nature13121. Epub 2014 Mar 26.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Division of Molecular Carcinogenesis, Cancer Systems Biology Centre and Cancer Genomics Centre Netherlands, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands [2]. ; 1] Division of Molecular Carcinogenesis, Cancer Systems Biology Centre and Cancer Genomics Centre Netherlands, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands [2] Department of Biochemistry, The Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, Quebec H3G 1Y6, Canada [3]. ; Division of Molecular Carcinogenesis, Cancer Systems Biology Centre and Cancer Genomics Centre Netherlands, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands. ; Institut Gustave Roussy, 114 Rue Edouard Vaillant, 94800 Villejuif, France. ; Division of Medical Oncology, Cancer Systems Biology Centre and Cancer Genomics Centre Netherlands, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands. ; Division of Pathology, Cancer Systems Biology Centre and Cancer Genomics Centre Netherlands, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands. ; 1] Division of Molecular Carcinogenesis, Cancer Systems Biology Centre and Cancer Genomics Centre Netherlands, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands [2] Department of Pathology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. ; 1] University of Torino, Department of Oncology, Str prov 142 Km 3.95, 10060 Candiolo, Torino, Italy [2] Candiolo Cancer Institute - FPO, IRCCS, Str prov 142 Km 3.95, 10060 Candiolo, Torino, Italy. ; Candiolo Cancer Institute - FPO, IRCCS, Str prov 142 Km 3.95, 10060 Candiolo, Torino, Italy. ; 1] University of Torino, Department of Oncology, Str prov 142 Km 3.95, 10060 Candiolo, Torino, Italy [2] Candiolo Cancer Institute - FPO, IRCCS, Str prov 142 Km 3.95, 10060 Candiolo, Torino, Italy [3] FIRC Institute of Molecular Oncology (IFOM), 20139 Milano, Italy.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24670642" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antineoplastic Agents/*administration & dosage/*pharmacology ; Cell Aging/drug effects ; Cell Proliferation/drug effects ; Drug Resistance, Neoplasm/drug effects/genetics ; Female ; Flow Cytometry ; Gene Expression Regulation, Neoplastic/drug effects ; Gene Library ; Humans ; Indoles/administration & dosage/pharmacology ; Melanoma/*drug therapy/enzymology/genetics/pathology ; Mice ; Mitogen-Activated Protein Kinase Kinases/antagonists & inhibitors/metabolism ; Protein Kinase Inhibitors/*administration & dosage/*pharmacology ; Proto-Oncogene Proteins B-raf/antagonists & inhibitors/*genetics/metabolism ; RNA, Small Interfering ; Receptor Protein-Tyrosine Kinases/biosynthesis/genetics/metabolism ; Receptor, Epidermal Growth Factor/biosynthesis/genetics/metabolism ; Receptor, Platelet-Derived Growth Factor beta/biosynthesis/genetics/metabolism ; SOXE Transcription Factors/deficiency/genetics ; Signal Transduction/drug effects ; Sulfonamides/administration & dosage/pharmacology ; Transforming Growth Factor beta/metabolism/pharmacology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 4
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  • 6
    Publication Date: 2012-02-08
    Description: Carcinomas are comprised of transformed epithelial cells that are supported in their growth by a dedicated neovasculature. How the genetic milieu of the epithelial compartment influences tumor angiogenesis is largely unexplored. Drugs targeted to mutant cancer genes may act not only on tumor cells but also, directly or indirectly, on the surrounding stroma. We investigated the role of the BRAFV600E oncogene in tumor/vessel crosstalk and analyzed the effect of the BRAF inhibitor PLX4720 on tumor angiogenesis. Knock-in of the BRAFV600E allele into the genome of human epithelial cells triggered their angiogenic response. In cancer cells harboring oncogenic BRAF, the inhibitor PLX4720 switches off the ERK pathway and inhibits the expression of proangiogenic molecules. In tumor xenografts harboring the BRAFV600E, PLX4720 extensively modifies the vascular network causing abrogation of hypoxia. Overall, our results provide a functional link between oncogenic BRAF and angiogenesis. Furthermore, they indicate how the tumor vasculature can be “indirectly” besieged through targeting of a genetic lesion to which the cancer cells are addicted.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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