Pt-Au Nanoparticles in Combination with Near-Infrared-Based Hyperthermia Increase the Temperature and Impact on the Viability and Immune Phenotype of Human Hepatocellular Carcinoma Cells

Near-infrared light (NIR)-responsive metal-based nanoparticles (NPs) could be used for tumour therapy. We examined how platinum (Pt), gold (Au), and core-shell Pt-Au NPs affect the viability of human hepatocellular carcinoma (HCC) cell lines (Hep3B, HepG2, and Huh7D-12) alone and in combination with NIR exposure. In addition, the expression of immune checkpoint molecules (ICMs) on the tumour cells was analysed. We revealed that the cytotoxicity and programmed cell death induction of Au and Pt-Au NPs toward HCC cells could be enhanced by NIR with 960 nm in a different way. Pt-Au NPs were the only particles that resulted in an additional temperature increase of up to 2 °C after NIR. Regarding the tumour cell immune phenotype, not all of the cells experienced changes in immune phenotype. NIR itself was the trigger of the alterations, while the NPs did not significantly affect the expression of most of the examined ICMs, such as PD-L1, PD-L1, HVEM, CD70, ICOS-L, Ox40-L, and TNFRSF9. The combination of Pt-Au NPs with NIR resulted in the most prominent increase of ICMs in HepG2 cells. We conclude that the thermotherapeutic effect of Pt-Au NP application and NIR could be beneficial in multimodal therapy settings in liver cancer for selected patients.