A research team led byProfessor Wang ZhongliangfromtheLabofMolecularImaging andTranslationalMedicine,the School of Life Science and Technology atXidianUniversity,has been focusingon the improvement of cancer photodynamic therapy andmadesignificantprogress.

In order to assess the risk of tumor metastasis after photodynamic therapy, the team used an orthotopic breast cancer model for evaluation. The results showed that photodynamic therapy would dramatically increase the risk of lung metastasis of breast cancer, and revealed that the increase of tumor hypoxia after photodynamic therapy was the key to tumor metastasis. Based on these findings, the teaminnovativelyproposed a post photodynamic oxygen supply (POS) strategytoremarkably reduce tumor metastasis caused by photodynamic therapy.Furthermore, the team explored the mechanism of POS strategy to reduce the risk of tumor metastasis.It was found thatPOS strategy reduces tumor metastasis by regulating HIF-1 α Snail-1, TGF-β, MMP-9, VEGFA, CCL-2, EPO, CAIX and GLUT-1. In addition, the team simulatedthe clinical experiment of photodynamic therapyinsmall animalmodels byusingthe clinically-approved photodynamic therapy drug (hypericin) and oxygen supplysystem(mask oxygen inhalation method) to evaluate the clinical transformation prospect of POS strategy. The results showed that POS strategyindeedeffectively blockedtumor metastasis.

This strategyis expected to reduce the risk of metastasis in other oxygen consuming therapies such as radiotherapy and sonodynamic therapy, thus havingbroad prospects in clinical application. This research progress was recently published in the top journal Nano Letters(https://pubs.acs.org/doi/10.1021/acs.nanolett.2c02983).