Date Published: April 17, 2019
Publisher: Public Library of Science
Author(s): Jang Ho Cho, Ju-Sun Kim, Seung Tae Kim, Jung Yong Hong, Joon Oh Park, Young Suk Park, Do-Hyun Nam, Dong Woo Lee, Jeeyun Lee, Aamir Ahmad.
We aimed to establish a fluorescence intensity-based colony area sweeping method by selecting the area of highest viability among patient-derived cancer cells (PDC) which has high tumor heterogeneity. Five gastric cancer cell lines and PDCs were screened with 24 small molecule compounds using a 3D micropillar/microwell chip. 100 tumor cells per well were immobilized in alginate, treated with the compounds, and then stained and scanned for viable cells. Dose response curves and IC50 values were obtained based on total or selected area intensity based on fluorescence. Unlike homogeneous cell lines, PDC comprised of debris and low-viability cells, which resulted in an inaccurate estimation of cell viability using total fluorescence intensity as determined by high IC50 values. However, the IC50 of these cells was lower and accurate when calculated based on the selected-colony-area method that eliminated the intensity offset associated with the heterogeneous nature of PDC. The selected-colony-area method was optimized to accurately predict drug response in micropillar environment using heterogeneous nature of PDCs.
Despite advances in targeted therapy and immunotherapy for solid cancer, one of the most challenging problems in oncology is that development of active drugs is still a slow multi-layered, complicated process. Considering the time consumption, high cost, and low success rate of pre-clinical and clinical development of oncology drugs, more efficient and accurate platforms for oncology drug screening are urgently needed.
Patient-derived cancer cells are more representative of the in vivo tumor microenvironment. In the present study, we examined the potential of using a fluorescence intensity-based colony area sweeping method for high throughput quantitative analysis of 3D-cultured patient-derived cancer cells as a novel approach in predicting drug responses in these cells. By selecting a high viability colony area using an intensity threshold, we could successfully eliminate the intensity offset and solve the problem associated with the heterogeneous nature of patient-derived cancer cells. To the best of our knowledge, this is the first study to address this tumor heterogeneity issue.