Image analysis of 3D conjunctival melanoma cell cultures following electrochemotherapy

Abstract

Three-dimensional (3D) cell cultures represent small avascular tumors in vitro and simulate some of the biological characteristics of solid tumors, enhancing the evaluation of anticancer drug efficacy. Automated image analysis can be used for the assessment of tumor growth and documentation of changes in the size parameters of 3D tumor spheroids following anticancer treatments such as electrochemotherapy. The objective of this article is to assess the effect of various electroporation (EP) conditions (500-750 Volts/cm, 8-20 pulses, 100 μs pulse duration, 5 Hz repetition rate) combined with different bleomycin concentrations (1-2.5 ug/mL) on normal epithelial (HCjE-Gi) and conjunctival melanoma (CRMM1, CRMM2) 3D-cell cultures, through an automated image analysis and a comparison with standard histological assays. A reduction in tumor mass with loss of cell definition was observed after ECT (750 Volts/cm with eight pulses and 500 Volts/cm with 20 pulses) with bleomycin (1 μg/mL and 2.5 μg/mL) in the histological and immunohistochemical analyses of 3D CRMM1 and CRMM2 spheroids, whereas an increase in volume and a decrease in sphericity was documented in the automated image analysis and 3D visualization of both melanoma cell lines. For all other treatment conditions and for the HCjE-Gi cell line, no significant changes to their morphological features were observed. Image analysis with integrated software tools provides an accessible and comprehensive platform for the preliminary selection of homogenous spheroids and for the monitoring of drug efficacy, implementing the traditional screening methods.