SCRATCH ASSAY TO TRACK CELL MIGRATION
A scratch assay measures the migration of cells across a scratch-induced gap in vitro. It may be used to assess cell proliferation and migration, often in cancer or wound healing studies. Tracking cell migration and proliferation provides a powerful tool to quantify metastatic potential and has proven particularly useful in understanding potential treatments to reduce metastasis in breast cancer.
The scratch assay is an easy and low-cost method to track cell migration in vitro. Real-time measurement across multiple wells can be done label-free with the Maestro Z. The rate of migration may differ by cell type or treatment and, depending on your cells and protocol, this assay may take several hours or a few days to complete. Continuous, label-free monitoring provides a true kinetic analysis and eliminates the guesswork associated with endpoint-only data.
Figure 1. (A) Scratch through confluent cells on plate.
(B) Cells migrating across scratch.
Scratch Assay Overview
Step 1: Cell Seeding and Growth
Cells are plated in the well and allowed to grow to confluence. Growth can be measured by the Maestro Z as a change in impedance over time. (Figure 1.A)
Step 2: Scratch Wound Production
The plate is removed from the Maestro Z and a scratch is created through the monolayer of cells. The change in confluence will be detected as a drop in impedance. (Figure 1.B left and Figure 2.B & 2.C below)
Step 3: Monitoring the Cell Migration/Wound healing
As the cells cover the scratch, impedance returns to pre-scratch levels. The differences in final impedance values and the rate of growth after scratch induction can be compared between cell types and treatments. (Figure 1.B left and Figure 2.D below)
Triple-negative breast cancer (TNBC) is an aggressive type of cancer with a poorer prognosis. It has limited therapeutic options and a high risk of metastatic re-occurrence. In vitro scratch assays can be used to assess cancer cell migration, a key factor in metastatic potential, and the effect of potential therapeutics. Below is example data (measured in impedance) comparing two breast cancer cell lines monitored continuously. This data was recorded on the Maestro Z
Figure 2. MCF-7, a hormone-receptor positive breast cancer line, and HCC1806, a triple-negative breast cancer line, were seeded into the CytoView-Z plate. Impedance was continuously monitored on the Maestro Z for 72 hours (step 1). Cells were switched to low-serum media for 24 hours prior to scratch induction and treatment with MCP, and then monitored over the next 72 hours (step 2). Each cell type exhibited a unique impedance profile during proliferation (A), and showed a sharp decrease in impedance resulting from the scratch (B and C). MCF-7 cells migrated very little over the next 72 hours (step 3) and normalized impedance remained consistently low (B). HCC1806 cells migrated to almost fully cover the gap and impedance nearly recovered to unscratched levels (C). The addition of modified citrus pectin (MCP) or PectaSol-C slowed migration shown here by a reduced recovery of impedance relative to the untreated condition (D).
Discover how other researchers are assessing cancer therapies
Glioblastoma is a particularly aggressive form of brain cancer, and has no effective treatments. Consequently, new therapeutic approaches, such as immunotherapies, are urgently needed to improve patient outcomes. One such therapy is chimeric antigen receptor (CAR) T cell therapy, a form of targeted immunotherapy that involves the modification of a patient’s own T cells to target specific antigens expressed on the tumor cell surface. In this webinar, Dr. Lohitash Karumbaiah and Megan Logan (University of Georgia), use label-free impedance measurements to assess in real-time, the targeting potency of activated human T cells on glioma cell monolayers and demonstrate the value of using an in vitro impedance-based assay to access therapeutic CAR T-cell potency against glioblastoma.
Download the app note to discover:
- How impedance measured the growth profile of two breast cancer cell lines.
- The effect of treatment on cell migration
WHY USE A KINETIC ASSAY?
Cell-based assays enable rapid evaluation of human biology in vitro, with substantial advantages in throughput and cost over tissue or animal models. However, many cell-based assays are endpoint assays, limited to a single snapshot in time. Axion BioSystems' Maestro Z platform now offers impedance-based cell analysis for real-time, continuous, label-free monitoring of your cells. Continuous data reveals the kinetics of cell-cell interactions and cell-drug responses for better mechanistic understanding without the time- and cost-intensive process of repeating multiple endpoint assays.