Photodynamic therapy induces autophagy-mediated cell death in human colorectal cancer cells via activation of the ROS/JNK signaling pathway

• Published in: Cell death & disease 2020-10, Vol.11 (10), p.938-938, Article 938
• Main Authors: Song, Changfeng, Xu, Wen, Wu, Hongkun, Wang, Xiaotong, Gong, Qianyi, Liu, Chang, Liu, Jianwen, Zhou, Lin
• Format: Article
• Language: English
• Subjects: 13/1; 13/109; 13/2; 13/31; 13/51; 13/89; 13/95; 14/19; 14/28; 14/35; 631/67/1059; 631/80/82/39; Animals; Antibodies; Antioxidants; Apoptosis; Autophagy; Biochemistry; Biomedical and Life Sciences; Cancer; Cell activation; Cell Biology; Cell Culture; Cell Death; Cell Line, Tumor; Colorectal cancer; Colorectal carcinoma; Colorectal Neoplasms - genetics; Humans; Image processing; Immunoblotting; Immunology; Life Sciences; Male; MAP Kinase Kinase 4 - metabolism; Mice; Phagocytosis; Photochemotherapy - methods; Photodynamic therapy; Phototoxicity; Reactive Oxygen Species; Signal Transduction; Transmission electron microscopy; Tumor suppressor genes; Tumorigenesis; Xenografts
• ISSN: 2041-4889; 2041-4889
• DOI: 10.1038/s41419-020-03136-y

Evidence has shown that m-THPC and verteporfin (VP) are promising sensitizers in photodynamic therapy (PDT). In addition, autophagy can act as a tumor suppressor or a tumor promoter depending on the photosensitizer (PS) and the cancer cell type. However, the role of autophagy in m-THPC- and VP-mediated PDT in in vitro and in vivo models of human colorectal cancer (CRC) has not been reported. In this study, m-THPC-PDT or VP-PDT exhibited significant phototoxicity, inhibited proliferation, and induced the generation of large amounts of reactive oxygen species (ROS) in CRC cells. From immunoblotting, fluorescence image analysis, and transmission electron microscopy, we found extensive autophagic activation induced by ROS in cells. In addition, m-THPC-PDT or VP-PDT treatment significantly induced apoptosis in CRC cells. Interestingly, the inhibition of m-THPC-PDT-induced autophagy by knockdown of ATG5 or ATG7 substantially inhibited the apoptosis of CRC cells. Moreover, m-THPC-PDT treatment inhibited tumorigenesis of subcutaneous HCT116 xenografts. Meanwhile, antioxidant treatment markedly inhibited autophagy and apoptosis induced by PDT in CRC cells by inactivating JNK signaling. In conclusion, inhibition of autophagy can remarkably alleviate PDT-mediated anticancer efficiency in CRC cells via inactivation of the ROS/JNK signaling pathway. Our study provides evidence for the therapeutic application of m-THPC and VP in CRC.