Therapeutic and immune effects of 5‐aminolevulinic acid photodynamic therapy on UVB‐induced squamous cell carcinomas in hairless mice

Abstract

The therapeutic effects of 5-aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) on cutaneous squamous cell carcinoma (SCC) are not fully understood, and the usefulness of topical PDT in the treatment of SCC is still debatable. The most interesting aspect in SCC PDT is perhaps its potential in inducing antitumor immune responses. In this study, cutaneous SCCs were established by UVB irradiation of hairless mice and treated with multiple ALA PDT. Immunohistochemistry assays showed that ALA PDT could induce quick apoptosis, overexpression of TNFa and marked increases in DCs, CD4+ and CD8 + cells in tumor interstitium and subcutaneous connective tissues. However, a complete response was only achieved for small SCCs. The clinical value of ALA PDT-induced specific antitumor immune responses in long-term control of SCCs deserves further study.

Improvement of DC vaccine with ALA-PDT induced immunogenic apoptotic cells for skin squamous cell carcinoma

“…In our previous studies, immunohistochemistry assays showed the numbers of DCs, CD4+ and CD8+ T cells distributed in the tumor tissues increased gradually after topical PDT. In addition, there was a marked increase in TNF-α expression after PDT [41].…”

“…It has been demonstrated that PDT can generate a depot of tumor-associated antigens (TAAs) and, alone or in combination with other modalities, elicit antitumor immune responses. We have used an SCC mouse model to study therapeutic and immune effects of ALA-PDT and found that topical ALA-PDT could induce quick apoptosis, inhibit SCC growth and shrink tumor volume [41]. In our previous studies, immunohistochemistry assays showed the numbers of DCs, CD4+ and CD8+ T cells distributed in the tumor tissues increased gradually after topical PDT.…”

Treating cutaneous squamous cell carcinoma using 5-aminolevulinic acid polylactic-co-glycolic acid nanoparticle-mediated photodynamic therapy in a mouse model

“…Ten visible tumors of similar size were selected from each group. The volume of each tumor ranged between 61.60 and 96.28 mm 3 . ALA PLGA NP cream (ALA PLGA NP PDT group) and ALA cream (ALA PDT group) were topically applied onto tumor surfaces for appropriate times (according to the fluorescence curve).…”

“…The mice were observed daily, and the tumors were measured every week for 2 months. Mice with a maximum tumor volume 500 mm 3 were killed by cervical dislocation.…”

“…It might be particularly suitable for large and multifocal lesions located on the face and external genital area. 2 Although ALA PDT shows some promise for the treatment of superficial SCC, 3 it is not currently recommended for the treatment of invasive SCC, mainly due to the limited bioavailability of ALA in the skin tissue. 4,5 Nanoparticles (NPs) might be a useful approach for delivering ALA in topical PDT, since NPs might improve ALA stability and cutaneous penetration.…”