Hormonal Modulation of Ishikawa Cells During Three-Dimensional Growth In Vitro

Objectives: The Ishikawa endometrial cancer cell line is hormonally responsive, expressing estrogen and progesterone receptors (ER, PR) when grown in traditional monolayer culture. The purpose of this paper is to demonstrate a three-dimensional spheroid culture system for cancer cells. We used this system to determine the response of the Ishikawa cell line to estradiol-17β (E), tamoxifen (T), megestrol acetate (MA), and progesterone (P). Methods: Ishikawa cells were incubated in polyurethane culture bags using phenol red-free media containing ethanol (0.1%, controls), E (1 μmol, or 1 nmol), T (1 μmol, or 10 nmol), MA (1 μmol, or 10 nmol), or P (1 μmol). Cellular morphology was assessed by hematoxylin and eosin staining, and expression of estrogen and progesterone receptors was determined immunohistochemically using an immunoperoxidase technique. Results: Cells in control cultures demonstrated minimal organization and lacked hormone receptors. In contrast, cells exposed to either E or T displayed significant glandular formation, with multicellular, microvilli-rich, columnar epithelia exhibiting polarized nuclear arrangements. Within 4 weeks, E- and T-treated cultures showed upregulated nuclear staining for PR, with little ER present. Cells treated with MA or P showed less glandular organization but expressed ER with PR downregulation. Conclusions: These data support the use of this novel three-dimensional culture system to study the modulation of tumor cell biologic activity in response to hormonal agents. Future applications of this model include examining in vitro responsiveness of cancer cells lines to additional biologic agents and chemotherapeutic regimens.