Continuous, label-free, 96-well-based determination of cell migration using confluence measurement

Is laccase from medicinal mushroom Cerrena unicolor cytotoxic to colon cancer cell line CT-26?

INTRODUCTION AND OBJECTIVE

Colorectal cancer takes an increasing toll every year. Despite the dynamic development of pharmacology, there is still no drug that would be strong enough to cause apoptosis of cancer cells, but at the same time would be free from numerous side effects. Taking traditional Eastern medicine into account, studies were carried out using an extract - laccase (LAC) from a medical mushroom called Cerrena unicolor- on CT-26 colon cancer cells. Preliminary cytotoxicity tests have already confirmed that the examined extract affects cancer cells and at the same time has no significant effect on L929 cells. The Electric Cell-substrate Impedance Sensing system (ECIS) and standard methods were used in this work. ECIS used in this study is an advanced in vitro impedance measuring system.

MATERIALS AND METHODS

The CT-26 and L929 cells were treated by five different concentrations of the LAC preparation ranging from 0.025 to 250 μg/mL. Concentrations selected for the ECIS system assay were: 0.25;2.5 and 250 μg/mL. The default optimal frequencies in the ECIS system for Resistance (R) 4000Hz, Impedance (Z) 16000Hz, Capacitance (C) 64000Hz were used.

RESLUTS

ECIS results demonstrate the potential anti-cancer activity of the laccase preparation against CT-26 cancer cells, and affect theL929 cells in to a lesser extent. Thanks to the use of the ECIS research technique, it was possible to monitor live changes in cell morphology and physiology, which translates into accurate conclusions about the action of the tested preparation.

Introducing Wound Healing Assays in the Undergraduate Biology Laboratory Using Ibidi Plates

The wound healing assay is a simple and inexpensive method that allows researchers to experimentally mimic cell growth and migration leading to wound healing. In this assay, a wound is created on a monolayer of cultured mammalian cells and cell migration is monitored. Micrographs are captured at regular intervals during the duration of the experiment. These microscopy images are analyzed to compare cell migration and wound closure under different conditions. Introduction of different cytotoxic treatments into a wound healing assay can provide information as to whether a particular drug or compound of interest has the ability to affect cell migration. This type of analysis is important when assessing the ability of a particular cancer cell line to display invasive and metastatic behaviors. One of the challenges of this assay is to create the original wound in a way that is consistent across plates or treatments, facilitating comparisons across experimental groups. This is a particular challenge when using the wound healing assay in the context of an undergraduate biology class to expose students to a distinct form of mammalian cell culture and help them apply scientific knowledge and research skills. We found an easy way to overcome this obstacle by using ibidi plates. In this article, we provide a simple protocol to use ibidi plates and HeLa cells to set up wound healing assays. This laboratory exercise allows undergraduate students to utilize different skills developed through cell culture experience, such as growing, treating, and imaging mammalian cells.