Suppression of Cancer Cell Stemness and Drug Resistance via MYC Destabilization by Deubiquitinase USP45 Inhibition with a Natural Small Molecule

Cancer stem cells (CSCs) play significant roles in cancer development, drug resistance and cancer recurrence. In cancer treatments based on the CSC characteristics and inducing factors, MYC is a promising target for therapeutic molecules. Although it has been regarded as an undrugable target, its stability tightly regulated by the ubiquitin–proteasome system offers a new direction for molecule targeting and cancer treatment. Herein we report our discoveries in this research area, and we have found that deubiquitinase USP45 can directly bind with MYC, resulting in its deubiquitination and stabilization. Further, USP45 overexpressing can upregulate MYC, and this overexpressing can significantly enhance cancer development, cancer cell stemness and drug resistance. Interestingly, without enhancing cancer development, MYC silencing with shRNA can only suppress USP45-induced stemness and drug resistance. Moreover, we have identified that USP45 can be specifically bound and inhibited by a natural small molecule (α-mangostin), in turn significantly suppressing USP45-induced stemness and drug resistance. Since USP45 is significantly expressed in cervical tumors, we have discovered that the combination of α-mangostin and doxorubicin can significantly inhibit USP45-induced cervical tumorigenesis in an animal model. In general, on the basis of our USP45 discoveries on its MYC deubiquitination and α-mangostin inhibition, suppressing USP45 has opened a new window for suppressing cancer development, stemness and drug resistance

Synergy between Polyamine and Anionic Surfactant: A Bioinspired Approach for Ordered Mesoporous Silica

A novel bioinspired approach for ordered mesoporous silica was developed on the basis of the synergic coassembly between polyamine and an anionic surfactant as a template. With the help of cationic polyamine, anionic surfactant micelles could be utilized as a mesostructure template, whereas with the aid of the anionic surfactant micelles the cationic polyamine chains underwent aggregation to exert their ability to induce silica condensation. Mesoporous silicas with well-ordered mesostructure of <i>Fd</i>-3<i>m</i> symmetry and 3D hexagonal close-packed mesostructure (hcp) were fabricated. Because of the abundant types of anionic surfactants and polyamines, the synthesis approach can be regarded as a general method for anionic-surfactant-templated mesoporous silica, and new mesostructures and morphologies are expected