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The Bag-1 inhibitor, Thio-2, reverses an atypical 3D morphology driven by Bag-1L overexpression in a MCF-10A model of ductal carcinoma in situ

The Bag-1 inhibitor, Thio-2, reverses an atypical 3D morphology driven by Bag-1L overexpression in a MCF-10A model of ductal carcinoma in situ
The Bag-1 inhibitor, Thio-2, reverses an atypical 3D morphology driven by Bag-1L overexpression in a MCF-10A model of ductal carcinoma in situ
Mammary MCF-10A cells seeded on reconstituted basement membrane form spherical structures with a hollow central lumen termed acini which are a physiologically-relevant model of mammary morphogenesis. Bcl-2 associated athanogene 1 (Bag-1) is a multifunctional protein overexpressed in breast cancer and ductal carcinoma in situ (DCIS). When present in the nucleus Bag-1 is predictive of clinical outcome in breast cancer. Bag-1 exists as three main isoforms, which are produced by alternative translation initiation from a single mRNA. The long isoform of Bag-1, Bag-1L, contains a nuclear localisation sequence not present in the other isoforms. When present in the nucleus Bag-1L, but not the other Bag-1 isoforms, can interact with and modulate the activities of oestrogen, androgen, and vitamin D receptors, Overexpression of Bag-1 mRNA in MCF-10A, is known to produce acini with luminal filling reminiscent of DCIS. As this mRNA predominantly overexpresses the short isoform of Bag-1, Bag-1S, we set out to examine whether the nuclear Bag-1 isoform is sufficient to drive premalignant change by developing a Bag-1L overexpressing MCF-10A model. Two clones differentially overexpressing Bag-1L were grown in 2D and 3D cultures and compared to an established model of HER2-driven transformation. In 2D cultures, Bag-1L overexpression reduced proliferation but did not affect insulin responsiveness or clonogenicity. Acini formed by Bag-1L-overexpressing cells exhibited reduced luminal clearing when compared to controls. An abnormal branching morphology was also observed which correlated with the level of Bag-1L overexpression suggesting further malignant change. Treatment with Thio-2, a small-molecule inhibitor of Bag-1 reduced the level of branching. In summary, 3D cultures of MCF-10A mammary epithelial cells overexpressing Bag-1L demonstrate a premalignant phenotype with features of DCIS. Using this model to test the small molecule Bag-1 inhibitor, Thio-2, reveals its potential to reverse the atypical branched morphology of acini which characterises this premalignant change.
1-8
Papadakis, E.S.
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Barker, C.R.
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Syed, H.
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Reeves, T.
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Schwaiger, S.
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Stuppner, H.
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Troppmair, J.
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Blaydes, J.P.
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Cutress, R.
68ae4f86-e8cf-411f-a335-cdba51797406
Papadakis, E.S.
ac2d55b0-7788-4157-a6c6-d8c87bcfdbe0
Barker, C.R.
67738d0c-3e20-4d23-b5f6-f25e368eaf3e
Syed, H.
917e246d-2e60-472f-8d30-94b01ef28958
Reeves, T.
47be25a6-47bf-4e7c-8c39-ff9a3a2f6924
Schwaiger, S.
c80a64c2-def9-4955-99a0-c5e039ffe7af
Stuppner, H.
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Troppmair, J.
8cc89b0f-efd0-480f-8034-235fcc4dc475
Blaydes, J.P.
e957f999-fd91-4f77-ad62-5b4ef069b15b
Cutress, R.
68ae4f86-e8cf-411f-a335-cdba51797406

Papadakis, E.S., Barker, C.R., Syed, H., Reeves, T., Schwaiger, S., Stuppner, H., Troppmair, J., Blaydes, J.P. and Cutress, R. (2016) The Bag-1 inhibitor, Thio-2, reverses an atypical 3D morphology driven by Bag-1L overexpression in a MCF-10A model of ductal carcinoma in situ. Oncogenesis, 5, 1-8, [e215]. (doi:10.1038/oncsis.2016.10).

Record type: Article

Abstract

Mammary MCF-10A cells seeded on reconstituted basement membrane form spherical structures with a hollow central lumen termed acini which are a physiologically-relevant model of mammary morphogenesis. Bcl-2 associated athanogene 1 (Bag-1) is a multifunctional protein overexpressed in breast cancer and ductal carcinoma in situ (DCIS). When present in the nucleus Bag-1 is predictive of clinical outcome in breast cancer. Bag-1 exists as three main isoforms, which are produced by alternative translation initiation from a single mRNA. The long isoform of Bag-1, Bag-1L, contains a nuclear localisation sequence not present in the other isoforms. When present in the nucleus Bag-1L, but not the other Bag-1 isoforms, can interact with and modulate the activities of oestrogen, androgen, and vitamin D receptors, Overexpression of Bag-1 mRNA in MCF-10A, is known to produce acini with luminal filling reminiscent of DCIS. As this mRNA predominantly overexpresses the short isoform of Bag-1, Bag-1S, we set out to examine whether the nuclear Bag-1 isoform is sufficient to drive premalignant change by developing a Bag-1L overexpressing MCF-10A model. Two clones differentially overexpressing Bag-1L were grown in 2D and 3D cultures and compared to an established model of HER2-driven transformation. In 2D cultures, Bag-1L overexpression reduced proliferation but did not affect insulin responsiveness or clonogenicity. Acini formed by Bag-1L-overexpressing cells exhibited reduced luminal clearing when compared to controls. An abnormal branching morphology was also observed which correlated with the level of Bag-1L overexpression suggesting further malignant change. Treatment with Thio-2, a small-molecule inhibitor of Bag-1 reduced the level of branching. In summary, 3D cultures of MCF-10A mammary epithelial cells overexpressing Bag-1L demonstrate a premalignant phenotype with features of DCIS. Using this model to test the small molecule Bag-1 inhibitor, Thio-2, reveals its potential to reverse the atypical branched morphology of acini which characterises this premalignant change.

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Accepted/In Press date: 16 December 2015
e-pub ahead of print date: 4 April 2016
Published date: April 2016
Organisations: Cancer Sciences

Identifiers

Local EPrints ID: 389854
URI: http://eprints.soton.ac.uk/id/eprint/389854
PURE UUID: f15ff024-2bb5-4234-8924-ea55f0606101
ORCID for C.R. Barker: ORCID iD orcid.org/0000-0001-8263-4151
ORCID for J.P. Blaydes: ORCID iD orcid.org/0000-0001-8525-0209

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Date deposited: 17 Mar 2016 10:19
Last modified: 15 Mar 2024 03:07

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Contributors

Author: E.S. Papadakis
Author: C.R. Barker ORCID iD
Author: H. Syed
Author: T. Reeves
Author: S. Schwaiger
Author: H. Stuppner
Author: J. Troppmair
Author: J.P. Blaydes ORCID iD
Author: R. Cutress

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