2.8. Xenograft Assay in Nude Mice

Athymic nude (nu/nu) mice were obtained from Chongqing Medical University. 4-week-old male mice were injected with A375 cells (3 × 10⁶ cells) in the right flanks into the subdermal space. Tumor volumes were estimated every other day by caliper measurements, and tumor volumes were calculated by the formula (volume = tumor length in mm × width² in mm × 0.5236). Once tumors reached a mean volume of 30–50 mm³, mice were randomly allocated into four groups and treated with either DMSO or BR (2 mg/kg) or UVA (75 kJ/m²) and in combination of BR and UVA every other day for seven days. Mice were sacrificed, and tumors were dissected. Formalin-fixed, paraffin-embedded tumor tissue sections were used for IHC, whereas snap-frozen tissues were subjected to Western blot analysis.