Polymers of 2,5-Dihydroxybenzoic Acid Induce Formation of Spheroids in Mammalian Cells

Abstract

Cells attached to a substrate and grown in two dimensions (2D) or suspended culture cannot accurately replicate intercellular interactions in tissues and organs. Spheroids, being three-dimensional (3D) formations, are more accurately reproduce the structure of organs or neoplasms. Spheroids compared to 2D cultures demonstrate an increased survival, corresponding morphology, and a hypoxic core, which is observed in native tumors in vivo. Tumor cell spheroids also represent models of the metastatic process. Therefore, spheroids are currently widely used for testing new anticancer drugs. However, obtaining and using 3D cultures can be associated with a number of difficulties, such as the need for expensive reagents and equipment, the low rate of formation of spheroids of the required size, and the occurrence of long-term changes in cell metabolism, which depend on the methods used to create spheroids. We have found that incubation of tumor and normal cells in the presence of polymers of 2,5-dihydroxybenzoic acid (2,5-DHBA) that are nontoxic to cells can induce the formation of 3D structures. Based on this, a new method for the rapid production of 3D cultures is developed and this approach does not require the use of additional equipment, expensive reagents, and does not have a long-term effect on cell homeostasis. The spheroids obtained by this method represent models of three-dimensional structures and can be used for biological studies of intercellular interactions and detection of pharmaceutical products.