Phytic acid-modified CeO2 as Ca2+ inhibitor for a security reversal of tumor drug resistance.

Ca2+ plays critical roles in the development of diseases, whereas existing various Ca regulation methods have been greatly restricted in their clinical applications due to their high toxicity and inefficiency. To solve this issue, with the help of Ca overexpressed tumor drug resistance model, the phytic acid (PA)-modified CeO2 nano-inhibitors have been rationally designed as an unprecedentedly safe and efficient Ca2+ inhibitor to successfully reverse tumor drug resistance through Ca2+ negative regulation strategy. Using doxorubicin (Dox) as a model chemotherapeutic drug, the Ca2+ nano-inhibitors efficiently deprived intracellular excessive free Ca2+, suppressed P-glycoprotein (P-gp) expression and significantly enhanced intracellular drug accumulation in Dox-resistant tumor cells. This Ca2+ negative regulation strategy improved the intratumoral Dox concentration by a factor of 12.4 and nearly eradicated tumors without obvious adverse effects. Besides, nanocerias as pH-regulated nanozyme greatly alleviated the adverse effects of chemotherapeutic drug on normal cells/organs and substantially improved survivals of mice. We anticipate that this safe and effective Ca2+ negative regulation strategy has potentials to conquer the pitfalls of traditional Ca inhibitors, improve therapeutic efficacy of common chemotherapeutic drugs and serves as a facile and effective treatment platform of other Ca2+ associated diseases. Electronic Supplementary Material: Supplementary material (further details of the XRD pattern of CeO2, TEM images, XPS spectra, cellular uptake study, cytotoxicity data, apoptosis study, biodistribution, and biosecurity of nanocerias in vivo, etc.) is available in the online version of this article at 10.1007/s12274-022-4069-0. © Tsinghua University Press 2022.

Phytic acid-modified CeO2 as Ca2+ inhibitor for a security reversal of tumor drug resistance