Rapid spheroid assays in a 3-dimensional cell culture chip

Abstract

Objective: The spheroid model provides a physiological platform to study cancer cell biology and drug sensitivity. Usage of bovine collagen I for spheroid assays is costly especially when experiments are conducted in 24-well plates, as high volume of bovine collagen I is needed. The aim of the study was to downsize spheroid assays to a microfluidic 3D cell culture chip and compare the growth, invasion and response to drug/compound of spheroids embedded in the 3D chip to spheroids embedded in 24-well plates.

Results: Spheroids generated from nasopharyngeal carcinoma cell line HK-1 continuously grew and invaded into collagen matrix in a 24-well plate. Similar observations were noticed with spheroids embedded in the 3D chip. Large spheroids in both 24-well plate and the 3D chip disintegrated and invaded into the collagen matrix. Preliminary drug sensitivity assays showed that the growth and invasion of spheroids were inhibited when spheroids were treated with combination of cisplatin and paynantheine at high concentrations, in a 24-well plate. Comparable findings were obtained when spheroids were treated with the same drug combination in the 3D chip. Moving forward, spheroid assays could be performed in the 3D chip in a more high-throughput manner with minimal time and cost.

Keywords: 3D cell culture chip; Bovine collagen I; Cisplatin; Mitragyna alkaloid; Nasopharyngeal carcinoma; Paynantheine; Spheroids.

Fig. 1

The 3D cell culture chip. a The design of the 3D cell culture chip (AIM Biotech). The chip is designed as a standard size microscope specimen slide and it consists of three columns. Each column comprises of a gel channel surrounded by two media channels. Spheroids were passed through the gel channels after resuspending the spheroids with collagen. Media channels were filled with either complete media or complete media plus drugs depending on the objectives of the experiment. b Suspension of collagen matrix with spheroids into the gel channels of the 3D chip. c Hydrating the media channel ports with media only or media + drug. d Replenishment of media or media + drug in the chip

Fig. 2

Growth and invasion of HK-1 spheroids in the 24-well plate and in the 3D chip. a Growth and invasion of an untreated HK-1 spheroid embedded into collagen matrix in the 24-well plate. Spheroid continuously grew and invaded into the collagen matrix. Images were masked using Image J to show clarity of the growth and invasion of the spheroids. Image crop factor: 500 × 500. Images were resized to 120 × 120 pt on Adobe Illustrator. (Size bar: 200 μm). b Graphs show corresponding quantification of spheroid growth in the 24-well plate for the days shown, n = 2 spheroids. Error bars indicate standard errors. c Growth and invasion of an untreated HK-1 spheroid embedded into collagen matrix in the 3D chip. Spheroid continuously grew and invaded into the collagen matrix. Images were masked using Image J to show clarity of the growth and invasion of the spheroids. Image crop factor: 798 × 900. Images were resized to 120 × 140 pt on Adobe Illustrator. (Size bar: 200 μm). d Graphs show corresponding quantification of spheroid growth in the 3D chip for the days shown, n = 2 spheroids. To eliminate the different spheroid sizes on day 0, spheroid growth on day 0 was set at zero (spheroid growth on day 0—spheroid growth on day 0). The relative spheroid growth for each day was determined by subtracting the spheroid growth obtained on a particular day with the spheroid growth obtained at day 0 (for example, spheroid growth on day 2—spheroid growth on day 0). Error bars indicate standard errors

Fig. 3

The effect of combination of cisplatin and paynantheine on the growth and invasion of HK-1 spheroids. Spheroids embedded in the 24-well plate and in the 3D chip were treated with combination of cisplatin and paynantheine at high concentrations. a The drug combination inhibited the growth and invasion of the spheroid in the 24-well plate. Images were masked using Image J to show clarity of the growth and invasion of the spheroids. Image crop factor: 900 × 900. Images were resized to 120 × 102 pt on Adobe Illustrator. (Size bar: 200 μm). b The drug combination inhibited the growth and invasion of the spheroid in the 3D chip. Images were masked using Image J to show clarity of the growth and invasion of the spheroids. Image crop factor: 798 × 900. Images were resized to 120 × 140 pt on Adobe Illustrator. (Size bar: 200 μm)