Sulfamoylated Estradiol Analogs Targeting the Actin and Microtubule Cytoskeletons Demonstrate Anti-Cancer Properties In Vitro and In Ovo

Simple Summary The naturally occurring derivative of estrogen, 2-methoxyestradiol (2-ME), has been shown to have good anti-cancer properties. However, it is broken down too quickly within the blood to be clinically useful. We designed 2-ME analogs with modifications which could avoid rapid metabolism, would preferably stay in the tumor, and were more toxic to cancer cells. Here, we looked more closely at how these compounds work within cancer cells, and how they communicate within themselves and with their environment. ESE-15-one and ESE-16 interfere with the functioning of the intracellular cytoskeleton (actin and microtubules), sending messages that stop cell division, intracellular transport of proteins, and cell migration and invasion, eventually inducing cell suicide. They also inhibited the movement of cells that make blood vessels that would support tumor growth. Using eggs with chicken embryos, we could show that the compounds reduced the tumor size and diminished the spread of cancer cells in a living system.Abstract The microtubule-disrupting agent 2-methoxyestradiol (2-ME) displays anti-tumor and anti-angiogenic properties, but its clinical development is halted due to poor pharmacokinetics. We therefore designed two 2-ME analogs in silico-an ESE-15-one and an ESE-16 one-with improved pharmacological properties. We investigated the effects of these compounds on the cytoskeleton in vitro, and their anti-angiogenic and anti-metastatic properties in ovo. Time-lapse fluorescent microscopy revealed that sub-lethal doses of the compounds disrupted microtubule dynamics. Phalloidin fluorescent staining of treated cervical (HeLa), metastatic breast (MDA-MB-231) cancer, and human umbilical vein endothelial cells (HUVECs) displayed thickened, stabilized actin stress fibers after 2 h, which rearranged into a peripheral radial pattern by 24 h. Cofilin phosphorylation and phosphorylated ezrin/radixin/moesin complexes appeared to regulate this actin response. These signaling pathways overlap with anti-angiogenic, extra-cellular communication and adhesion pathways. Sub-lethal concentrations of the compounds retarded both cellular migration and invasion. Anti-angiogenic and extra-cellular matrix signaling was evident with TIMP2 and P-VEGF receptor-2 upregulation. ESE-15-one and ESE-16 exhibited anti-tumor and anti-metastatic properties in vivo, using the chick chorioallantoic membrane assay. In conclusion, the sulfamoylated 2-ME analogs displayed promising anti-tumor, anti-metastatic, and anti-angiogenic properties. Future studies will assess the compounds for myeloproliferative effects, as seen in clinical applications of other drugs in this class.