Ebselen oxide and derivatives are new allosteric HER2 inhibitors for HER2-positive cancers

Human epidermal growth factor receptor 2 (ErbB2/HER2) is a tyrosine kinase receptor that is overexpressed in 25% of primary human breast cancers, as well as in multiple other cancers. HER2-targeted therapies improved progression-free and overall survival in patients with HER2+ breast cancers. However, associated resistance mechanisms and toxicity highlight the need for new therapeutic approaches for these cancers. We recently established that, in normal cells, HER2 is stabilized in a catalytically repressed state by direct interaction with members of the ezrin/radixin/moesin (ERM) family. In HER2-overexpressing tumors, the low expression of moesin contributes to the aberrant activation of HER2. Through a screen designed to find moesin-mimicking compounds, we identified ebselen oxide. We show that ebselen oxide, and some derivatives, conferred an efficient allosteric inhibition of overexpressed HER2, as well as mutated and truncated oncogenic forms of HER2, which are resistant to current therapies. Ebselen oxide selectively inhibited anchorage-dependent and -independent proliferation of HER2+ cancer cells and showed a significant benefit in combination with current anti-HER2 therapeutic agents. Finally, ebselen oxide significantly blocked HER2+ breast tumor progression in vivo. Collectively, these data provide evidence that ebselen oxide is a newly identified allosteric inhibitor of HER2 to be considered for therapeutic intervention on HER2+ cancers.

Localized chemotherapy approaches and advanced drug delivery strategies: a step forward in the treatment of peritoneal carcinomatosis from ovarian cancer

Peritoneal carcinomatosis (PC) is a common outcome of epithelial ovarian carcinoma and is the leading cause of death for these patients. Tumor location, extent, peculiarities of the microenvironment, and the development of drug resistance are the main challenges that need to be addressed to improve therapeutic outcome. The development of new procedures such as HIPEC (Hyperthermic Intraperitoneal Chemotherapy) and PIPAC (Pressurized Intraperitoneal Aerosol Chemotherapy) have enabled locoregional delivery of chemotherapeutics, while the increasingly efficient design and development of advanced drug delivery micro and nanosystems are helping to promote tumor targeting and penetration and to reduce the side effects associated with systemic chemotherapy administration. The possibility of combining drug-loaded carriers with delivery via HIPEC and PIPAC represents a powerful tool to improve treatment efficacy, and this possibility has recently begun to be explored. This review will discuss the latest advances in the treatment of PC derived from ovarian cancer, with a focus on the potential of PIPAC and nanoparticles in terms of their application to develop new therapeutic strategies and future prospects.