CD271 Targeted Near-Infrared Photoimmunotherapy for Local Depletion of Cancer Stem Cells

Cancer stem cells have the ability to self-renew and show resistance to conventional drug therapy and radiation therapy, potentially resulting in cancer recurrence and metastasis. Since inadequate treatment of cancer stem cells can cause local recurrence and metastasis, an important goal of cancer therapy is to target these cancer stem cells. Near-infrared photoimmunotherapy (NIR-PIT) is one of the cell-selective cancer treatments. Cancer stem cell can be locally depleted by NIR-PIT using appropriate antibody-photoabsorber (IR700) conjugates (APCs). In this study, the efficacy of NIR-PIT against CD271, which has been reported as a marker of cancer stem cells in various cancers, including head and neck cancers, was confirmed using two different human head and neck cancer cell lines, HPCM2 and HSC-3. We demonstrated the efficacy of NIR-PIT against CD271 in both in vitro and in vivo experiments. The efficacy of CD271-targeted NIR-PIT was comparable to that of EGFR-targeted NIR-PIT in mouse models, even though the cell-surface expression of CD271 was lower than that of EGFR. This is the first study to demonstrate the efficacy of CD271-targeted NIR-PIT, which we believe will have a significant impact on the future development of cancer stem cell-targeted therapy.