Microfluidic cell sorting by stiffness to examine heterogenic responses of cancer cells to chemotherapy

Muhymin Islam,Alexander Alexeev,Todd Sulchek,Bushra Tasadduq,Betsy Campbell,Hannah Brink,Edmund K Waller,Brynn Mcfarland,Roman Mezencev,Wilbur Lam

doi:10.1038/s41419-018-0266-x

Abstract

Cancers consist of a heterogeneous populations of cells that may respond differently to treatment through drug-resistant sub-populations. The scarcity of these resistant sub-populations makes it challenging to understand how to counter their resistance. We report a label-free microfluidic approach to separate cancer cells treated with chemotherapy into sub-populations enriched in chemoresistant and chemosensitive cells based on the differences in cellular stiffness. The sorting approach enabled analysis of the molecular distinctions between resistant and sensitive cells. Consequently, the role of multiple mechanisms of drug resistance was identified, including decreased sensitivity to apoptosis, enhanced metabolism, and extrusion of drugs, and, for the first time, the role of estrogen receptor in drug resistance of leukemia cells. To validate these findings, several inhibitors for the identified resistance pathways were tested with chemotherapy to increase cytotoxicity sevenfold. Thus, microfluidic sorting can identify molecular mechanisms of drug resistance to examine heterogeneous responses of cancers to therapies.

Highlights

Chemotherapy is one of the most common modalities of cancer treatment[1,2], but its use is complicated by innate and acquired resistance of cancer cells to commonly used anticancer drugs[3]
A microfluidic device has been used to sort drug-resistant and sensitive leukemia cells by differences in their stiffness that result after treatment with chemotherapy, which was previously identified as an early biophysical response of cells to toxic agents[17,18,19,20]
For K562 cells treated with 2 μM daunorubicin, the ABCB1 expression was detected in 8.95% and 95.45% cells from soft and stiff outlets, respectively (Fig. S4)

Summary

Introduction

Chemotherapy is one of the most common modalities of cancer treatment[1,2], but its use is complicated by innate and acquired resistance of cancer cells to commonly used anticancer drugs[3]. A microfluidic device has been used to sort drug-resistant and sensitive leukemia cells by differences in their stiffness that result after treatment with chemotherapy, which was previously identified as an early biophysical response of cells to toxic agents[17,18,19,20]. For K562 cells treated with 2 μM daunorubicin, the ABCB1 expression was detected in 8.95% and 95.45% cells from soft and stiff outlets, respectively (Fig. S4).

Results

Conclusion