LAUSR

Cancer cells survive by relying on oxidative stress defense against the accumulation of reactive oxygen species (ROS) during tumor formation. ROS‐sensitive TRPA1 ion channels are overexpressed in breast cancer cells and induce a large influx of Ca2+ which upregulates the anti‐apoptotic pathway to lead breast cancer cells to produce oxidative stress defense and enhance the resistance to ROS related chemotherapy. Targeting and inhibiting the TRPA1 ion channels are critical for breaking down the oxidative stress defense system and overcoming cellular resistance. Here, near‐infrared (NIR) light‐responsive conjugated polymer nanoparticles are designed and prepared to promote apoptosis of breast cancer cells, reduce cell drug resistance and suppress tumor growth through the remote and precise regulation of TRPA1 ion channels. Upon 808 nm laser irradiation, the nanoparticles block the formation of Ca2+/CaM complex and regulate the content of MCL‐1 protein. Especially, the nanoparticles overcome drug resistance of cancer cells, therefore accelerating apoptosis of cancer cells and suppressing tumor growth in mice. Compared with carboplatin, the volume of tumor induced by NPs‐H decreases by 54.1%. This work provides a strategy to disrupt the oxidative stress defense system and downregulate the antiapoptotic signaling pathway in cancer cells.