The effects of As4O6 were studied as adjuvant on photodynamic therapy. As4O6 is considered to have anticancer activity
via several biological actions such as free radical producing and inhibition of VEGF expression. In vitro experiments,
cell proliferation and morphology were determined by MTT assay. Also, quantitative PCR array was performed to study
the synergetic mechanism. Additionally, this study was supported by the finding that combination of photodynamic
therapy and As4O6 shows an inhibition effect of tumor growth in C57BL/6 mice with TC-1 cells xenographs in vivo.
Radachlorin and As4O6 significantly inhibited TC-1 cell proliferation in a dose-dependent manner (P < 0.05). Antiproliferative
effect of combination treatment was significantly higher than those of TC-1 cells treated with either
photodynamic therapy or As4O6 (62.4 and 52.5% decrease, respectively, compared to photodynamic therapy or As4O6
alone, P < 0.05). In addition, cell proliferation in combination of photodynamic therapy and As4O6 treatment
significantly decreased by 77.4% compared to vehicle-only treated TC-1 cells (P < 0.05). Cell survival pathway (Naip1,
Tert and Aip1) and p53-dependent pathway (Bax, p21Cip1, Fas, Gadd45, IGFBP-3 and Mdm-2) were markedly increased
by combination treatment of photodynamic therapy and As4O6. Besides, the immunology response NEAT pathway (Ly-
12, CD178 and IL-2) also modulated after combination treatment of photodynamic therapy and As4O6. This combination
effect apparently shows a same pattern in vivo model. These findings suggest the benefit of the combination treatment of
photodynamic therapy and As4O6 for the inhibition of cervical cancer growth.