Determining Optimal Inhibitory Tumor Treating Field Frequency for Cancer Cells: A Non-invasive In Vitro Method to Assess the Effect of TTFields on Cancer Cell Viability

Abstract

Source: Porat, Y. et al. Determining the Optimal Inhibitory Frequency for Cancerous Cells Using Tumor Treating Fields (TTFields). J. Vis. Exp. (2017)

This video demonstrates the effect of TTField application on the growth of ovarian cancer cell lines in vitro. This assay can help determine the optimal frequency of the electric field that can lead to a maximum reduction in the number of cancer cells.

Protocol

1. TTFields In Vitro Application System - Base Plate and Dish Maintenance

1. Rinse dishes and dish covers under running tap water. Then, rinse with deionized water and air-dry face down.
2. If a chemotherapeutic agent/drug has been added to dishes in a prior experiment, fill each dish with a 5% light detergent solution and leave overnight.
   1. Rinse the dishes thoroughly under running tap water to avoid any traces of detergent inside the dish. Rinse the dishes and dish covers with deionized water and air-dry face down.
3. Insert the clean and dry dishes with their covers into sterilization bag....

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Invitro system and software	Novocure	ITG1000 and IBP1000	Each unit contains 1 TTFields generator, 1 base plate, 8 TTFields dishes with covers and 1 flat cable.
Sterilization bags	Westfield medica	24882
Plastic cover slides	Thermo Scientific (NUNC)	174977	Pre treated and sterilized
Glass cover slides	Thermo Scientific (Menzel-Gläser)	CB00220RA1	Sterilize if necessary
Dulbecco’s modified Eagle’s medium	Biological Industries (Israel)	01-055-1A	Warm in 37 °C water bath before use
RPMI 1640	Gibco	21875-034	Warm in 37 °C water bath before use
Fetal Bovine Serum (FBS)	Biological Industries (Israel)	04-007-1A	Warm in 37 °C water bath before use
L-Glutamine 200 mM (100x)	Gibco	25030-029
Pen/Strep (10,000 U/mL Penicillin, 10,000 µg/mL Streptomycin)	Gibco	15140-122
Sodium Pyruvate solution 100 mM	Biological Industries (Israel)	03-042-1B
Hepes buffer 1 M	Biological Industries (Israel)	03-025-1B
Insulin solution from bovine pancreas	Sigma-Aldrich	10516-5ML
0.25% Trypsin/EDTA	Biological Industries (Israel)	03-050-1B	Warm in 37 °C water bath before use
Methanol	Merck	1.06009.2511	Cool to -20 °C in the freezer before use
PBS	Biological Industries (Israel)	02-023-1A	Without calcium and magnesium
A2780	ECACC	93112519	Grow in RPMI 1640 supplemented with FBS (10%), pen/strep (100 U/ mL / 100 µg/mL), sodium pyruvate (1 mM) and Hepes buffer (12 mM).
F98	ATCC	CRL-2397	Grow in Dulbecco’s modified Eagle’s medium supplemented with FBS (10%), pen/strep (100 U/mL / 100 µg/mL), sodium pyruvate (1 mM) and glutamine (2 mM).
Ovcar-3	ATCC	HTB-161	Grow in RPMI 1640 supplemented with FBS (20%), pen/strep (100 U/ mL / 100 µg/mL), sodium pyruvate (1 mM), Hepes buffer (12 mM) and insulin (10 µg/mL).
U-87 MG	ATCC	HTB-14	Grow in Dulbecco’s modified Eagle’s medium supplemented with FBS (10%), pen/strep (100 U/mL / 100 µg/mL), sodium pyruvate (1 mM) and glutamine (2 mM).
Refrigerated CO2 incubator	CARON	7404-10-3
Laminar flow cabinet	ADS Laminair	Bio12 and VSM12