Anti-recurrence/metastasis and chemosensitization therapy with thioredoxin reductase-interfering drug delivery system

Thioredoxin reductase (TrxR) is an essential mammalian enzyme that possesses a selenocysteine active site. TrxR is overexpressed in many malignant tumors and has a close relationship with apoptosis, drug resistance, recurrence and metastasis of tumors. Recently, TrxR has emerged as a promising target for anticancer therapy. Herein, we developed a TrxR-interfering drug delivery system (DDS) based on RGD-PEG-PUSeSe-PEG-RGD self-assembling micelles for imaging-guided gemcitabine (GEM) chemosensitization and anti-recurrence/metastasis therapy. The diselenide-containing micelles were degraded in response to TrxR stimuli for GEM releasing. In the meantime, the dissociated polymers’ chain segments targeted the active site of TrxR via Se–Se/Se–S dynamic reactions for activity inhibition. This inhibition by the micelles not only provided chemosensitization, but reduced tumor recurrence/metastasis risk via the induction of residual tumor cell apoptosis by triggering ROS production post-chemotherapy. In this work, we took the transformation between Se-containing dynamic covalent bonds developed by our group from in vitro to in vivo , which furthered the knowledge on the biochemistry of selenium and provided aspects to develop new TrxR inhibitors. Overall, the TrxR-interfering DDS combined excellent antitumor effects for primary solid tumors with the inhibition of tumor recurrence/metastasis during post-treatment care, providing new perspectives for efficient cancer therapy.