Epigallocatechin gallate with photodynamic therapy enhances anti-tumor effects in vivo and in vitro

Abstract

Objectives: To evaluate anti-tumor effects of combined photodynamic therapy and epigallocatechin-3-gallate (EGCG).

Materials and methods: TC-1 cells were injected into C57BL/6 mice. Mice were grouped by 7 into 4 groups as PDT, EGCG, combined PDT with EGCG, and control group. The photosensitizer Radachlorin was used. The light source was a diode laser with 662 nm wavelength. In vitro TC-1 cells were treated with Radachlorin and irradiated. In vivo, when tumors were 8-10mm, Radachlorin was injected into mice and irradiated. For in vitro, different doses of EGCG were added to culture dishes. For combination, EGCG was added to the cells. 2.5 or 5 μg/ml of Radachlorin was added to the cells. Cells were incubated with EGCG and/or Radachlorin and laser irradiated. In vivo, EGCG were given for 20 days, alone or after PDT treatment. Cell growth inhibition was determined using MTT assay. Tumor growth inhibition assays were done in each group. Tumor growth was measured using caliper. Western blottings were performed with primary antibodies as COX-2, p21, p53, PARP, Bax, P-p38, VEGF, HIF-1α, MMP9 and actin.

Results: The cell growth and the tumor volume in PDT combined with EGCG treatment group was significantly suppressed, compared with control and PDT or EGCG alone treated groups. We have shown that PDT combined with EGCG in vivo increase levels of both p21 and p53. Both Bax and activated PARP genes were significantly expressed.

Conclusions: It is suggested that high anti-cancer activity of combined photodynamic therapy with EGCG may be useful for effective cancer therapy.

Keywords: Anti-tumor effect; EGCG; Photodynamic therapy.