In vitro effects of photodynamic therapy induced by chloroaluminum phthalocyanine nanoemulsion.
BACKGROUND
The photodynamic therapy (PDT) has been used to treat cancer mainly by inducing oxidative stress. Our aim was to evaluate the effect of PDT and its combination with methoxyamine (MX), a blocker of base excision repair (BER), in cells expressing high levels of the APE1 protein, which is involved in cell oxidative damage response.


METHODS
The HeLa and A549 cells were treated for 3h with chloroaluminum phthalocyanine incorporated into a well-designed nanoemulsion (ClAlPc/NE); and then irradiated by visible light (@670nm) with doses of 0.1, 0.5 and 1.0J/cm2. A simultaneous combination of MX+ClAlPc/NE was performed and then irradiated with the selected dose of 0.5J/cm2. The treatments were evaluated in terms of viability, clonogenicity, DNA fragmentation, and cell death mechanism by apoptosis and/or necrosis.


RESULTS
The APE1 protein expression observed was higher in HeLa than in A549. Both cell lines exhibited substantial differences in cell cytotoxicity. The PDT decreased the clonogenicity of HeLa by inducing apoptosis (sub-G1 and annexin detection). Additionaly, the MX potentiates the PDT-effects in HeLa. Otherwise, low cytotoxicity was observed in A549 cells.


CONCLUSIONS
The PDT induced apoptosis in high APE1 expressive HeLa cells, and the blockage of BER by MX increased its effects.
Department of Chemistry, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil.
Leonardo Pereira
LP
Franchi
Department of Chemistry, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil.
Camila F
CF
Amantino
Department of Chemistry, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil.
Maryanne T
MT
Melo
Department of Biology, Faculty of Philosophy, Sciences and Letters of RibeirãoPreto, USP, Ribeirão Preto, SP, Brazil.
Ana Paula
AP
de Lima Montaldi
Department of Bioprocess and Biotechnology, School of Pharmaceutical Sciences of Araraquara, UNESP, Araraquara, SP, Brazil.
Fernando L
FL
Primo
Department of Chemistry, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil. Electronic address: atedesco@usp.br.
Antonio Claudio
AC
Tedesco
D000072283:A549 Cells; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects; D004655:Emulsions; D006367:HeLa Cells; D006801:Humans; D007211:Indoles / Q000008:administration & dosage* / Q000737:chemistry*; D053769:Nanocapsules / Q000008:administration & dosage / Q000737:chemistry* / Q000648:ultrastructure; D009374:Neoplasms, Experimental / Q000188:drug therapy* / Q000473:pathology; D009942:Organometallic Compounds / Q000008:administration & dosage* / Q000737:chemistry*; D010316:Particle Size; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000737:chemistry; D016896:Treatment Outcome
D004655:Emulsions; D007211:Indoles; D053769:Nanocapsules; D009942:Organometallic Compounds; D017319:Photosensitizing Agents; C044797:chloroaluminum phthalocyanine
Cancer cell lines; Chloroaluminum phthalocyanine; Cytotoxicity; DNA repair; Flow cytometry