Background: Head and neck squamous cell carcinoma (HNSCC) is one of the most common malignancies, with high rates of mortality and morbidity worldwide. Owing to the special anatomical location of this tumor, an effective, minimally invasive treatment with low systemic toxicity is highly desirable. Hydrogels have shown great potential for tumor-targeting therapy, with excellent performance. However, there have been few reports on co-loading photosensitizers and chemotherapeutic drugs into hydrogels. In this study, we synthesized a nano doxorubicin-indocyanine green matrix metalloproteinase (MMP)-responsive hydrogel (denoted as NDIMH), combining chemotherapy and phototherapy, to achieve superior antitumor efficacy.
Methods: First, NDIMH was synthesized and characterized by scanning electron microscopy and drug-release assays. Second, the photosensitivity properties and antitumor efficiency of this drug delivery system were studied in vivo and in vitro. Last, the imaging and biodistribution of NDIMH were monitored using the Maestro EX in vivo imaging system.
Results: The nanodrugs loaded into the smart hydrogel exhibited uniform size distribution, excellent size stability, and a sustained release in the presence of MMP-2. NDIMH showed ideal photosensitivity characteristics under light. NDIMH with 808 nm near-infrared (NIR) irradiation effectively inhibited the viability, invasion, and metastasis of SCC-15 in vitro. After intratumoral injection of NDIMH with 808 nm NIR illumination, the hydrogels exhibited favorable synergistic antitumor efficacy and acceptable biosafety. Additionally, fluorescence imaging showed that NDIMH could significantly improve the retention of nanodrugs at the tumor site.
Conclusion: The intratumoral injection of NDIMH with 808 nm NIR irradiation could be a promising chemophototherapy alternative for HNSCC.
Keywords: MMP-responsive; chemophototherapy; doxorubicin; hydrogel; indocyanine green.