Background: Despite recent advances in therapies, resistance to chemotherapy remains a critical problem in the clinical management of colorectal cancer (CRC). Cancer stem cells (CSCs) play a central role in therapy resistance. Thus, elimination of CSCs is crucial for effective CRC therapy; however, such strategies are limited. Autophagy promotes resistance to cancer therapy; however, whether autophagy protects CSCs to promote resistance to CRC-therapy is not well understood. Moreover, specific and potent autophagy inhibitors are warranted as clinical trials with hydroxychloroquine have not been successful. Methods: Colon cancer cells and tumoroids were used. Fluorescent reporter-based analysis of autophagy flux, spheroid and side population (SP) culture, and qPCR were done. We synthesized 36-077, a potent inhibitor of PIK3C3/VPS34 kinase, to inhibit autophagy. Combination treatments were done using 5-fluorouracil (5-FU) and 36-077. Results: The 5-FU treatment induced autophagy only in a subset of the treated colon cancer. These autophagy-enriched cells also showed increased expression of CSC markers. Co-treatment with 36-077 significantly improved efficacy of the 5-FU treatment. Mechanistic studies revealed that combination therapy inhibited GSK-3β/Wnt/β-catenin signaling to inhibit CSC population. Conclusion: Autophagy promotes resistance to CRC-therapy by specifically promoting GSK-3β/Wnt/β-catenin signaling to promote CSC survival, and 36-077, a PIK3C3/VPS34 inhibitor, helps promote efficacy of CRC therapy.

During the past decade, researchers have designed and synthesised a variety of artificial molecular pumps capable of the active transport of macrocycles (rings) from free solution into mechanically interlocked states. In their ability to drive non-equilibrium transport, these artificial molecular pumps imitate natural transmembrane transporters, which are widespread in living organisms. Despite this resemblance, ring-threading molecular pumps have not previously been operated in aqueous supramolecular assemblies in imitation of their natural counterparts. Here, we demonstrate the active transport of charged macrocycles from aqueous solution into micellar assemblies of polymer chains, which remain stable after pumping has occurred. While micelles are used routinely to encapsulate and solubilise hydrophobic small molecules in aqueous solution, this report, by contrast, shows that artificial molecular pumps can harness external energy to drive hydrophilic molecules into micelles where they are stored at concentrations far from equilibrium.