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ENGINEERED IN VITRO BREAST CANCER MODELS SHOW PHENOTYPIC DIFFERENTIATION CHARACTERISTICS OF EARLY VS. LATE-STAGE DISEASE

Venkata Krishnan, Harini (2016) ENGINEERED IN VITRO BREAST CANCER MODELS SHOW PHENOTYPIC DIFFERENTIATION CHARACTERISTICS OF EARLY VS. LATE-STAGE DISEASE. Master's Thesis, University of Pittsburgh. (Unpublished)

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Abstract

Cancer drug discovery and development is challenged by poor prediction of drug responses in in vitro disease models. Results from clinical trials suggest that just 5% of drugs tested are successful in patients. Currently used disease models such as two-dimensional (2D) cell monolayers and in vivo animal models fail to recapitulate the human tumor microenvironment. Further, disease progression from the non-invasive to metastatic stage needs models that can recapitulate each stage. Hence, there is an unmet need to develop three-dimensional (3D) models that capture natural tumor progression for better understanding of disease biology as well as screening of drug regimens acting on different disease stages.
In this work, we have characterized 3D breast microtumors ranging from 150 to 600 μm diameters using non-invasive T47D cells with precise control over physicochemical microenvironmental factors. In this study, we test the hypothesis that the size-controlled microtumors will exhibit differential biochemical features and drug response arising from unique molecular signatures created by variable tumor microenvironments. To test this hypothesis, we studied the physicochemical features such as hypoxia, reactive oxygen species, metabolic activity, and cell cycle status. Additionally, the expression of key regulators of growth/proliferation pathways in breast cancer progression such as estrogen receptor alpha (ER-α) and growth factor receptor/s was studied and efficacy of clinically used inhibitors such as 4-hydroxytamoxifen (4-OHT) was evaluated.
The results indicated that large T47D microtumors (600 μm) exhibited traits of clinically advanced tumors such as collective cell migration, mesenchymal marker upregulation, loss of ER-α and endocrine resistance in contrast to the small microtumors (150 μm). Thus, the engineered in vitro models could successfully recapitulate phenotypic differentiation characteristics of early vs. late disease stage in the same non-invasive T47D cells just by precisely controlling the microtumor size, which further regulated the tumor microenvironmental factors. The large microtumors (600 μm) were found to resemble features of advanced stage breast cancer whereas the small microtumors (150 μm) recapitulated features of early stage breast cancer. Hence, such disease stage-specific microtumor models could help in the evaluation of crucial mechanisms in breast tumor progression correlated to tumor size and in the screening of therapeutic candidate/s.


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Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Venkata Krishnan, Harinihav13@pitt.eduHAV13
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Thesis AdvisorSant, Shilpashs149@pitt.eduSHS149
Committee MemberJohnston, Paulpaj18@pitt.eduPAJ18
Committee MemberGibbs, Robertgibbssr@pitt.eduGIBBSSR
Date: 9 August 2016
Date Type: Publication
Defense Date: 27 July 2016
Approval Date: 9 August 2016
Submission Date: 9 August 2016
Access Restriction: 2 year -- Restrict access to University of Pittsburgh for a period of 2 years.
Number of Pages: 60
Institution: University of Pittsburgh
Schools and Programs: School of Pharmacy > Pharmaceutical Sciences
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: 3D cell culture, stage specific model, breast cancer progression
Date Deposited: 09 Aug 2016 17:10
Last Modified: 09 Aug 2018 05:15
URI: http://d-scholarship.pitt.edu/id/eprint/29199

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