Hypoxia-stimulated tumor therapy associated with the inhibition of cancer cell stemness.

Cancer stem cells (CSCs) possess self-renewal and clonal tumor initiation capacities, which lead to drug resistance and tumor recurrence. In this work, a hypoxia-stimulated strategy based on a smart triblock vector was developed to enhance therapeutic efficacy through the inhibition of cancer stemness. The triblock precursor was designed with a fluorescence chromophore for monitoring hypoxia, a methoxy nitro-unit for biorecognition, and a poly(ethylene glycol)-folate for cancer cell targeting. As the degree of hypoxia increases, the vectors were progressively dissociated as indicated by the enhanced fluorescence intensity in hypoxic cells and compacted three-dimensional spheres. Furthermore, the expression of stem cell markers such as CD133 and SOX2 was significantly inhibited, and the serial passaging of CSCs was notably impaired after treating CSCs with the vectors. The inhibition of cancer cell stemness significantly improved the anticancer efficiency in vivo. Moreover, tumor initiation was reduced and the median survival time of xenograft tumor models was prolonged by regulating cell stemness under hypoxia. Overall, this work provides a promising approach to inhibit tumor resistance and recurrence for efficient tumor therapy.