Acid‐Degradable Hydrogen‐Generating Metal‐Organic Framework for Overcoming Cancer Resistance/Metastasis and Off‐Target Side Effects

The development of stimuli‐responsively degradable porous carriers for both controlled drug release and high biosafety is vitally important to their clinical translation, but still challenging at present. A new type of porphyrin–iron metal organic framework (Fe‐MOF) nanocrystals is engineered here as acid‐degradable drug carrier and hydrogen donor by the coordination between porphyrin and zero‐valence Fe atom. Fe‐MOF nanocrystals exhibit excellent acid‐responsive degradation for H(2) generation and simultaneous release of the loaded drug for combined hydrogen‐chemotherapy of cancer multidrug resistance (MDR) and metastasis and for local hydrogen eradication of the off‐target induced toxic side effects of the drug to normal cells/tissues. Mechanistically, released H(2) assists chemotherapeutic drug to efficiently inhibit cancer metastasis by immunoactivating intratumoral M1‐phenotype macrophages and consequently downregulating the expression of metastasis‐related matrix metalloproteinase‐2 (MMP‐2) and can also downregulate the expressions of both P‐glycoprotein (P‐gp) protein and adenosine triphosphate (ATP) in MDR cancer cells to sensitize chemotherapeutic drug for enhanced damage to mitochondria and DNA. High anti‐MDR/antimetastasis efficacies and high biocompatibility endow Fe‐MOF nanocrystals and the Fe‐MOF‐based nanomedicine with high potential for clinical translation.