TiSe2-mediated sonodynamic and checkpoint blockade combined immunotherapy in hypoxic pancreatic cancer

Abstract Background Pancreatic cancer remains among the most prevalent and aggressive forms of cancer. While immunotherapeutic treatment strategies have shown some promise in affected patients, the benefits of these interventions have been limited by insufficient tumor infiltration by activated T cells. Results Here, Titanium diselenide (TiSe2) nanosheets were synthesized with good stability. When exposed to ultrasound (US), the TiSe2 nanosheets served as a reliable nano-sensitizer capable of inducing large amounts of reactive oxygen species (ROS) mediating sonodynamic therapy (SDT) under hypoxic and normoxic conditions. The tumor-released TAAs induced by TiSe2 nanosheet-mediated SDT promoted immunogenic cell death (ICD) conducive to the maturation of dendritic cells (DCs), and cytokine secretion and the subsequent activation and infiltration of T cells into the tumor. Combining TiSe2-mediated SDT with anti-PD-1 immune checkpoint blockade treatment led to the efficient suppression of the growth of both primary tumor and distant tumor, while simultaneously preventing lung metastasis. These improved immunotherapeutic and anti-metastatic outcomes were associated with activated systematic antitumor immune responses, including the higher levels of DC maturation and cytokine secretion, the increased levels of CD8+ T cells and the decreased levels of Treg cells infiltrated in tumors. Conclusion TiSe2 can be used as a sonosensitizer with good efficacy and high safety to mediate efficient SDT. The combination treatment strategy comprised of TiSe2-mediated SDT and PD-1 blockade activate anti-tumor immune responses effectively thorough inducing ICD, resulting in the inhibition the growth and metastasis of tumor. The combination therapy holds promise as a novel immunotherapy-based intervention strategy for pancreatic cancer patients.