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http://hdl.handle.net/2445/118067
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DC Field | Value | Language |
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dc.contributor.advisor | Albanell Mestres, Joan | - |
dc.contributor.advisor | Rovira López, Ana Ma. | - |
dc.contributor.author | Sabbaghi Mehrjardi, Mohammad Ali | - |
dc.contributor.other | Universitat de Barcelona. Facultat de Biologia | - |
dc.date.accessioned | 2017-11-23T10:28:17Z | - |
dc.date.available | 2018-03-19T23:01:16Z | - |
dc.date.issued | 2017-09-19 | - |
dc.identifier.uri | http://hdl.handle.net/2445/118067 | - |
dc.description.abstract | [eng] Trastuzumab-emtansine (T-DM1) is an antibody-cytotoxic agent (DM1) conjugated drug. DM1 delivery by trastuzumab inside the HER2 positive cells affects microtubule polymerization, cell cycle arrest and finally cell death. Although T-DM1 is approved for the treatment of HER2 positive metastatic breast cancer patients, primary and acquired resistance towards this drug is still a main challenge. Looking for the mechanisms of resistance is necessary to improve patient selection and to develop novel treatment strategies. Here, we focused on finding mechanisms of acquired resistance to T-DM1 in a panel of HER2 positive breast cancer cell lines (HCC1954, HCC1419 and SKBR3 parental vs. resistant cells) generated by an established protocol of T-DM1 exposure, increasing the concentration of T-DM1[1-4µg/mL], 3days on/3days off, for 54 days overall. We generated acquired resistant cells with different level of resistance to T-DM1 evaluated by 3, 7 and 10 days proliferation assay, using automated cell counting in SKBR3, HCC1419 and HCC1954 parental and the acquired resistant cells. Analysis of T-DM1 effects on cell cycle showed a significant induction of G2/M arrest in the parental cells, while this effect was not observed in the resistant cells. Expression/activity analysis of cyclin B1/CDK1 complex, the main apparatus involve in G2/M cell cycle arrest induction, showed a remarkable decrease in the basal level of cyclin B1 in the resistant cells. Cyclin B1 accumulation induced by T-DM1 in the parental cells was not observed in the resistant cells. CDK1 activity assay was also correlated with cyclin B1 expression, increasing following T-DM1 treatment in the parental cells, but not in the resistant cells. Functional analysis revealed that cyclin B1 knock down in the parental cells induced a significant T-DM1 resistance. Furthermore, the silencing of cdc20, a protein mainly involved in APC complex related cyclin B1 degradation, could sensitize the resistant cells to T-DM1. Finally, cyclin B1 induction by T-DM1 was confirmed in in vivo and ex vivo xenograft animal model and patients’ explants, respectively. By cyclin B1 induction pattern, we could categorize T-DM1 responsive/non-responsive in fresh breast cancer explants from HER2 positive breast cancer patients. Our results showed that T-DM1 induced G2/M cell cycle arrest in a cyclin B1/CDK1 dependent-manner. Lack of these effects appeared in acquired T-DM1 resistant cells. Besides, similar pattern in G2/M and cyclin B1 was verified in vivo and in patients explants. These data strongly suggest that induction of cyclin B1 is necessary for T-DM1 antitumor effects and emerges as a potential pharmacodynamic marker. Our finding also raises the question on what are the mechanisms leading to cyclin B1 dysregulation in resistant cells. | - |
dc.format.extent | 177 p. | - |
dc.format.mimetype | application/pdf | - |
dc.language.iso | eng | - |
dc.publisher | Universitat de Barcelona | - |
dc.rights | (c) Sabbaghi, 2017 | - |
dc.source | Tesis Doctorals - Facultat - Biologia | - |
dc.subject.classification | Càncer de mama | - |
dc.subject.classification | Anticossos monoclonals | - |
dc.subject.other | Breast cancer | - |
dc.subject.other | Monoclonal antibodies | - |
dc.title | Uncivering mechanisms of acquired resistance to trastuzumab-emtansine (T-DM1) in HER2 positive breast cancer | - |
dc.type | info:eu-repo/semantics/doctoralThesis | - |
dc.type | info:eu-repo/semantics/publishedVersion | - |
dc.date.updated | 2017-11-23T10:28:17Z | - |
dc.rights.accessRights | info:eu-repo/semantics/openAccess | - |
dc.identifier.tdx | http://hdl.handle.net/10803/456988 | - |
Appears in Collections: | Tesis Doctorals - Facultat - Biologia |
Files in This Item:
File | Description | Size | Format | |
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MASM_PhD_THESIS.pdf | 6.71 MB | Adobe PDF | View/Open |
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