Bioprinting as a tool to evaluate interactions of cancerous and noncancerous cells

摘要

Introduction: Cancer is becoming one the leading causes of death worldwide and, in particular, breast cancer, which is the second highest cause of cancer death for women. Despite declining rates in breast cancer death, cancer progression is not well understood. One promising technique for breast cancer research is inkjet printing, which is an inexpensive way to print precise patterns of cell and biomaterials with little reduction in cellular viability. The objective of this study was to characterize the interactions of cancerous and noncancerous breast cells after cells were printed into lines of varying distances apart using a modified inkjet printer, i.e. a bioprinter. Materials and Methods: Noncancerous MCF-10a and cancerous MCF-7 cells were printed into two opposing lines of varying distances apart onto collagen type Ⅰ coated slides. Baseline slides of printed MCF-10a cell lines were used to compare to the experimental slides. To assess the effect of the distance on printed lines, several testing methods were proposed, and samples were taken at time points Day 1 and Day 5 after printing. The testing methods included Hoechst stain, alamarBlue® assay, and flow cytometry. Results and Discussion: The Hoechst stain was used a visual examination of Die printed cellular lines (Figure 1), and the results imply cell communication decreases with increase in distance between lines. The alamarBlue® assay is used to establish the health of the cell, with higher reduction suggesting more cell growth. The experimental slides had a higher percent reduction than the baseline slides (Figure 2), possibly due to the MCF-7 cells growing much faster than the MCF-10a cells. The increase in distance between the lines showed an increase percent reduction of alamarBlue® (Figure 2) suggesting the distance has an effect on the cells. The expression of E-cadherin in both the MCF-7 and MCF-10a cells was used for flow cytometry with E-caherin expression measured through green fluorescence. The percentage of Day 1 green baseline and experimental cells increased with increase in distance between lines, but decreased at Day 5 (Figure 3). This result could suggest that E-cadherin expression is affected by the interactions of MCF-7 and MCF-10a cells, and the distance between the cells causes a change in expression. Conclusion: The results from the collected data lead to several general, key findings. First, the cancerous cells modified the cellular behavior of the noncancerous cells. Second, time played a key role in the performance of the cells, particularly with respect to metabolic activity. Last, the overall results point toward a change in cellular behavior with a change in distance between lines. The study laid the foundation for potential research to use a bioprinter for in vitro cancer models. Future studies should focus on improvements or alterations to the bioprinter and experimental analyses to enhance findings.