Sei-Jun Han

Photodynamic therapy‐generated tumor cell lysates with CpG‐oligodeoxynucleotide enhance immunotherapy efficacy in human papillomavirus 16 (E6/E7) immortalized tumor cells

Immunotherapy with photodynamic therapy (PDT) offers great promise as a new alternative for cancer treatment; however, its use remains experimental. In this study, we examined the immunotherapeutic significance of human papillomavirus (HPV)‐immortalized tumor cell lysates induced by PDT with CpG‐oligodeoxynucleotide (ODN). PDT‐cell lysates were generated by irradiating Radachlorin (5 µg/mL) preloaded TC‐1 cells carrying HPV 16 E7. PDT‐cell lysates plus ODN coinjection for protection against E7‐expressing tumors as well as specific immune responses were evaluated with the following tests: heat shock protein 70 (HSP70) enzyme‐linked immunosorbent assay, in vitro and in vivo tumor growth inhibition, interferon‐γ (IFN‐γ) and tumor necrosis factor‐α (TNF‐α) assay, cytotoxic T‐lymphocyte assay, and fluorescence activated cell sorting (FACS) analysis. PDT‐cell lysates plus ODN coinjection showed a significant suppression of tumor growth at both prophylactic and therapeutic levels, compared to PDT (or F/T)‐cell lysates or ODN alone. In addition, we evaluated the level of the immune response with the coinjection. HSP70, an important regulator of inflammatory and immune response, was observed in abundance in the PDT‐cell lysates. IFN‐γ production and cytotoxic T lymphocytes (CTL) responses were induced by PDT‐cell lysates plus ODN injection. The coinjection resulted in PDT‐cell lysate‐specific antibodies (IgG1, IgG2a, IgG2b, and IgG3) and T‐helper cell responses significantly higher than PDT‐cell lysates alone. Moreover, IFN‐γ production and CTL responses were significantly induced in the PDT‐cell lysate plus ODN immunized groups. These enhanced immune responses appeared to be mediated by CD8+ T cells only. These data suggest that PDT‐cell lysates plus ODN injection may be an effective approach to induce CTL immune responses as a possible immunotherapeutic strategy for cancer therapy. (Cancer Sci 2007; 98: 747–752)

Photodynamic Effects of Radachlorin® on Cervical Cancer Cells

PURPOSE Photodynamic therapy (PDT) is a novel treatment modality, which produces local tissue necrosis with laser light following the prior administration of a photosensitizing agent. Radachlorin has recently been shown to be a promising PDT sensitizer. In order to elucidate the antitumor effects of PDT using Radachlorin on cervical cancer, growth inhibition studies on a HPV-associated tumor cell line, TC-1 cells in vitro and animals with an established TC-1 tumor in vivo were determined. MATERIALS AND METHODS TC-1 tumor cells were exposed to various concentrations of Radachlorin and PDT, with irradiation of 12.5 or 25 J/cm(2) at an irradiance of 20 mW/cm(2) using a Won-PDT D662 laser at 662 nm in vitro. C57BL/6 mice with TC-1 tumor were injected with Radachlorin via different routes and treated with PDT in vivo. A growth suppression study was then used to evaluate the effects at various time points after PDT. RESULTS The results showed that irradiation of TC-1 tumor cells in the presence of Radachlorin induced significant cell growth inhibition. Animals with established TC-1 tumors exhibited significantly smaller tumor sizes over time when treated with Radachlorin and irradiation. CONCLUSION PDT after the application of Radachlorin appears to be effective against TC-1 tumors both in vitro and in vivo.

Photodynamic effects of Radachlorin® on cervical cancer model

Photodynamic therapy (PDT) has been reported to be effective for treating various tumors and induce apoptosis in many tumor cells. In this study, we examined a biological significance of PDT with a chlorin-based photosensitizer, Radachlorin®, in a cervical cancer model, TC-1 cells. When TC-1 cells were exposed to varied doses of Radachlorin® with light irradiation (6.25 J/cm2), PDT induced a dose-dependent growth inhibition of TC-1 cells. All of these cells were significantly damaged after light irradiation and categorized to be early and late apoptosis, as determined by annexin V staining. Radachlorin® localized primarily into the Golgi apparatus of cells in 12 h of the treatment, and weak fluorescence intensity was also detected in mitochondria. On the other hand, in the in vivo experiments, following light irradiation (100 J/cm2), retarded tumor growth was significant in mice treated with Radachlorin®, as compared to the control group. Taken together, we propose that PDT after the application of Radachlorin® may induce the Golgi apparatus-mediated apoptosis of cervical cancer cells in vitro, and also be effective in the mice system.