BODIPY-Based Analogue of the TREM2-Binding Molecular Adjuvant Sulfavant A, a Chemical Tool for Imaging and Tracking Biological Systems.

Recently, we described synthetic sulfolipids named Sulfavants as a novel class of molecular adjuvants based on the sulfoquinovosyl-diacylglycerol skeleton. The members of this family, Sulfavant A (1), Sulfavant R (2), and Sulfavant S (3), showed important effects on triggering receptor expressed on myeloid cells 2 (TREM2)-induced differentiation and maturation of human dendritic cells (hDC), through a novel cell mechanism underlying the regulation of the immune response. As these molecules are involved in biological TREM2-mediated processes crucial for cell survival, here, we report the synthesis and application of a fluorescent analogue of Sulfavant A bearing the 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene moiety (Me4-BODIPY). The fluorescent derivative, named PB-SULF A (4), preserving the biological activity of Sulfavants, opens the way to chemical biology and cell biology experiments to better understand the interactions with cellular and in vivo organ targets and to improve our comprehension of complex molecular mechanisms underlying the not fully understood ligand-induced TREM2 activity.

Regorafenib in combination with silybin as a novel potential strategy for the treatment of metastatic colorectal cancer.

PURPOSE: Regorafenib, an oral multikinase inhibitor, has demonstrated survival benefit in metastatic colorectal cancer (mCRC) patients that have progressed after all standard therapies. However, novel strategies to improve tolerability and enhance anti-cancer efficacy are needed. EXPERIMENTAL DESIGN: We have evaluated in vitro the effects of regorafenib in combination with silybin, a biologically active component extracted from the seeds of Silybum marianum, in a panel of human colon cancer cells. Furthermore, we have prospectively treated a cohort of 22 refractory mCRC patients with regorafenib plus silybin. RESULTS: Treatment with regorafenib determined a dose-dependent growth inhibition whereas treatment with silybin had no anti-proliferative effects among all cancer cells tested. The combined treatment with regorafenib and silybin induced synergistic anti-proliferative and apoptotic effects by blocking PI3K/AKT/mTOR intracellular pathway. Moreover, combined treatment with regorafenib and silybin increased the production of reactive oxygen species levels within cells. In an exploratory proof of concept clinical study in a cohort of 22 mCRC patients after failure of all standard therapies, the clinical activity of regorafenib in combination with silybin was assessed. A median progression-free survival of 10.0 months and a median overall survival of 17.6 months were observed in these patients. These results suggest that the combined treatment potentially increases the clinical efficacy of regorafenib. Moreover, due to its anti-oxidative properties, silybin could protect patients from drug-induced liver damages, allowing to continue an effective anti-cancer therapy. CONCLUSIONS: The present study suggests that silybin in combination with regorafenib is a promising strategy for treatment of metastatic colorectal patients.