A study on the mechanism of 5-aminolevulinic acid photodynamic therapy in vitro and in vivo in cervical cancer

Abstract

5-Aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) is a new ablation treatment for tumors, while its function mechanism in cervical cancer has not been elucidated. In this study, we investigated the effects of ALA-PDT on the cervical cancer cell line Me180, to search for optimal parameters of PDT. ALA-PDT on proliferation of Me180 was examined by MTT assay to find the optimal function parameters of ALA-PDT. Apoptosis was observed by using AnnexinV-FITC/PI double staining, Hoechst 33342 staining and May-Grünwald-Farbstoff Giemsa staining. Furthermore, we established a tumor model and 6 mice of each group underwent measurement of the tumor size on days 3, 7, 14, and 21 after treatment. The mRNA expression of survivin, bcl-2, p53, bax and bad in Me180 cells were detected by real-time fluorescence reverse transcription-polymerase chain reaction (RT-PCR) in vitro and in vivo. Finally, we compared the effects between topical and intravenous administration. Based on the above studies, we found ALA-PDT induced apoptosis and G0-G1 phase arrest of Me180 cells. The tumor volume of the topical administration and PDT group was the smallest at 7-14 days post-PDT. H&E staining showed remarkable subcutaneous necrosis in the PDT groups. The mRNA expression of survivin and bcl-2 in Me180 cells were suppressed post-PDT. Topical administration of PDT is recommended in treating cervical cancer so as to minimize the side-effects and inconvenience of phototoxic reaction brought by PDT. Our data may contribute to making the mechanism of PDT on cervical cancer clearer and give some useful suggestions for clinical application.