In vitro microtumors provide a physiologically predictive tool for breast cancer therapeutic screening
Gabriel Benton1, Gerald DeGray1, Hynda K Kleinman1
1Trevigen Inc., Gaithersburg, MD, United States of America.
Abstract:
Many anti-cancer drugs fail in human trials despite showing efficacy in preclinical models. It is clear that the in vitro assays involving 2D monoculture do not reflect the complex extracellular matrix, chemical, and cellular microenvironment of the tumor tissue, and this may explain the failure of 2D models to predict clinical efficacy. We first optimized an in vitro microtumor model using a tumor-aligned ECM, a tumor-aligned medium, MCF-7 and MDA-MB-231 breast cancer spheroids, human umbilical vein endothelial cells, and human stromal cells to recapitulate the tissue architecture, chemical environment, and cellular organization of a growing and invading tumor. We assayed the microtumor for cell proliferation and invasion in a tumor-aligned extracellular matrix, exhibiting collagen deposition, acidity, glucose deprivation, and hypoxia. We found maximal proliferation and invasion when the multicellular spheroids were cultured in a tumor-aligned medium, having low pH and low glucose, with 10% fetal bovine serum under hypoxic conditions. In a 7-day assay, varying doses of fluorouracil or paclitaxel had differential effects on proliferation for MCF-7 and MDA-MB-231 tumor spheroids in microtumor compared to 2D and 3D monoculture. The microtumors exhibited a tumor morphology and drug response similar to published xenograft data, thus demonstrating a more physiologically predictive in vitro model.
Insights
This study developed a microtumor model that better mimics human tumors. This advanced in vitro model shows improved prediction of anti-cancer drug efficacy compared to traditional 2D cultures.
Area of Science:
- Biomedical Engineering
- Cancer Research
- Drug Discovery
Background:
- Traditional 2D cell cultures fail to predict anti-cancer drug efficacy in human trials.
- Tumor microenvironments are complex, involving extracellular matrix, chemical gradients, and cellular interactions, which 2D models do not replicate.
Purpose of the Study:
- To develop and optimize an in vitro microtumor model that recapitulates key features of the human tumor microenvironment.
- To assess the physiological relevance and predictive power of this microtumor model for anti-cancer drug response.
Main Methods:
- Optimized an in vitro microtumor model using tumor-aligned extracellular matrix (ECM) and medium.
- Incorporated breast cancer cell lines (MCF-7, MDA-MB-231), endothelial cells, and stromal cells.
- Assayed cell proliferation and invasion under conditions mimicking tumor hypoxia, acidity, and nutrient deprivation.
Main Results:
- The microtumor model successfully recapitulated tumor tissue architecture, chemical environment, and cellular organization.
- Maximal proliferation and invasion were observed in a tumor-aligned medium under hypoxic, acidic, and low-glucose conditions.
- The microtumor model demonstrated differential drug responses to fluorouracil and paclitaxel, similar to published xenograft data.
Conclusions:
- The optimized microtumor model provides a more physiologically predictive in vitro system for evaluating anti-cancer drugs.
- This model addresses limitations of 2D and 3D monocultures in predicting clinical drug efficacy.
- The microtumor model shows promise for improving the success rate of anti-cancer drugs in human trials.
