Cyclical Treatment of Colorectal Tumor Spheroids Induces Resistance to MEK Inhibitors
Adaptive drug resistance is a major obstacle to successful treatment of colorectal cancers. Physiologic tumor models of drug resistance are crucial to understand mechanisms of treatment failure and improve therapy by developing new therapeutics and treatment strategies. Using our aqueous two-phase s...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2019-03-01
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| Series: | Translational Oncology |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1936523318305862 |
| _version_ | 1818544499768426496 |
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| author | Pradip Shahi Thakuri Gary D. Luker Hossein Tavana |
| author_facet | Pradip Shahi Thakuri Gary D. Luker Hossein Tavana |
| author_sort | Pradip Shahi Thakuri |
| collection | DOAJ |
| description | Adaptive drug resistance is a major obstacle to successful treatment of colorectal cancers. Physiologic tumor models of drug resistance are crucial to understand mechanisms of treatment failure and improve therapy by developing new therapeutics and treatment strategies. Using our aqueous two-phase system microtechnology, we developed colorectal tumor spheroids and periodically treated them with sub-lethal concentrations of three Mitogen Activated Kinase inhibitors (MEKi) used in clinical trials. We used long-term, periodic treatment and recovery of spheroids to mimic cycles of clinical chemotherapy and implemented a growth rate metric to quantitatively assess efficacy of the MEKi during treatment. Our results showed that efficacy of the MEKi significantly reduced with increased treatment cycles. Using a comprehensive molecular analysis, we established that resistance of colorectal tumor spheroids to the MEKi developed through activation of the PI3K/AKT/mTOR pathway. We also showed that other potential feedback mechanisms, such as STAT3 activation or amplified B-RAF, did not account for resistance to the MEKi. We combined each of the three MEKi with a PI3K/mTOR inhibitor and showed that the combination treatments synergistically blocked resistance to the MEKi. Importantly, and unlike the individual inhibitors, we demonstrated that synergistic concentrations of combinations of MEK and PI3K/mTOR inhibitors effectively inhibited growth of colorectal tumor spheroids in long-term treatments. This proof-of-concept study to model treatment-induced drug resistance of cancer cells using 3D cultures offers a unique approach to identify underlying molecular mechanisms and develop effective treatments. |
| first_indexed | 2024-12-11T22:49:17Z |
| format | Article |
| id | doaj.art-8e6e1ceb35a54a25ad6843712549be9b |
| institution | Directory Open Access Journal |
| issn | 1936-5233 |
| language | English |
| last_indexed | 2024-12-11T22:49:17Z |
| publishDate | 2019-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Translational Oncology |
| spelling | doaj.art-8e6e1ceb35a54a25ad6843712549be9b2022-12-22T00:47:30ZengElsevierTranslational Oncology1936-52332019-03-01123404416Cyclical Treatment of Colorectal Tumor Spheroids Induces Resistance to MEK InhibitorsPradip Shahi Thakuri0Gary D. Luker1Hossein Tavana2Department of Biomedical Engineering, The University of Akron, Akron, OH 44325, USADepartment of Radiology, University of Michigan, Ann Arbor, MI 48105, USA; Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48105, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48105, USADepartment of Biomedical Engineering, The University of Akron, Akron, OH 44325, USA; Address all correspondence to: Hossein Tavana, Ph.D., P. Eng., 260 S. Forge St., Akron, OH 44325.Adaptive drug resistance is a major obstacle to successful treatment of colorectal cancers. Physiologic tumor models of drug resistance are crucial to understand mechanisms of treatment failure and improve therapy by developing new therapeutics and treatment strategies. Using our aqueous two-phase system microtechnology, we developed colorectal tumor spheroids and periodically treated them with sub-lethal concentrations of three Mitogen Activated Kinase inhibitors (MEKi) used in clinical trials. We used long-term, periodic treatment and recovery of spheroids to mimic cycles of clinical chemotherapy and implemented a growth rate metric to quantitatively assess efficacy of the MEKi during treatment. Our results showed that efficacy of the MEKi significantly reduced with increased treatment cycles. Using a comprehensive molecular analysis, we established that resistance of colorectal tumor spheroids to the MEKi developed through activation of the PI3K/AKT/mTOR pathway. We also showed that other potential feedback mechanisms, such as STAT3 activation or amplified B-RAF, did not account for resistance to the MEKi. We combined each of the three MEKi with a PI3K/mTOR inhibitor and showed that the combination treatments synergistically blocked resistance to the MEKi. Importantly, and unlike the individual inhibitors, we demonstrated that synergistic concentrations of combinations of MEK and PI3K/mTOR inhibitors effectively inhibited growth of colorectal tumor spheroids in long-term treatments. This proof-of-concept study to model treatment-induced drug resistance of cancer cells using 3D cultures offers a unique approach to identify underlying molecular mechanisms and develop effective treatments.http://www.sciencedirect.com/science/article/pii/S1936523318305862 |
| spellingShingle | Pradip Shahi Thakuri Gary D. Luker Hossein Tavana Cyclical Treatment of Colorectal Tumor Spheroids Induces Resistance to MEK Inhibitors Translational Oncology |
| title | Cyclical Treatment of Colorectal Tumor Spheroids Induces Resistance to MEK Inhibitors |
| title_full | Cyclical Treatment of Colorectal Tumor Spheroids Induces Resistance to MEK Inhibitors |
| title_fullStr | Cyclical Treatment of Colorectal Tumor Spheroids Induces Resistance to MEK Inhibitors |
| title_full_unstemmed | Cyclical Treatment of Colorectal Tumor Spheroids Induces Resistance to MEK Inhibitors |
| title_short | Cyclical Treatment of Colorectal Tumor Spheroids Induces Resistance to MEK Inhibitors |
| title_sort | cyclical treatment of colorectal tumor spheroids induces resistance to mek inhibitors |
| url | http://www.sciencedirect.com/science/article/pii/S1936523318305862 |
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