RESUMO
Cutaneous melanoma (CM) poses a therapeutic challenge due to its aggressive nature and often limited response to conventional treatments. Exploring novel therapeutic targets is essential, and natural compounds have emerged as potential candidates. This study aimed to elucidate the impact of curcumin, a natural compound known for its anti-inflammatory, antioxidant, and anti-tumor properties, on metastatic melanoma cells, focusing on the purinergic system and immune responses. Human melanoma cell line SK-Mel-28 were exposed to different curcumin concentrations for either 6 or 24 h, after which we assessed components related to the purinergic system and the inflammatory cascade. Using RT-qPCR, we assessed the gene expression of CD39 and CD73 ectonucleotidases, as well as adenosine deaminase (ADA). Curcumin effectively downregulated CD39, CD73, and ADA gene expression. Flow cytometry analysis revealed that curcumin significantly reduced CD39 and CD73 protein expression at specific concentrations. Moreover, the A2A receptor's protein expression decreased across all concentrations. Enzymatic activity assays demonstrated that curcumin modulated CD39, CD73, and ADA activities, with effects dependent on concentration and duration of treatment. Extracellular ATP levels increased after 24 h of curcumin treatment, emphasizing its role in modulating hydrolytic activity. Curcumin also displayed anti-inflammatory properties by reducing NLRP3 gene expression and impacting the levels of key inflammatory cytokines. In conclusion, this study unveils the potential of curcumin as a promising adjuvant in CM treatment. Curcumin modulates the expression and activity of crucial components of the purinergic system and exhibits anti-inflammatory effects, indicating its potential therapeutic role in combating CM. These findings underscore curcumin's promise and warrant further investigation in preclinical and clinical settings for melanoma management.
RESUMO
Epidemiological studies indicate a role of genetic and environmental factors in Parkinson's disease involving alterations of the neuronal α-synuclein (α-syn) protein. In particular, a relationship between Parkinson's disease and occupational exposure to pesticides has been repeatedly suggested. Our objective was to precisely assess changes in α-syn levels in human neuroblastoma (SH-SY5Y) and melanoma (SK-MEL-2) cell lines following acute exposure to pesticides (rotenone, paraquat, maneb, and glyphosate) using Western blot and flow cytometry. These human cell lines express α-syn endogenously, and overexpression of α-syn (wild type or mutated A53T) can be obtained following recombinant adenoviral transduction. We found that endogenous α-syn levels in the SH-SY5Y neuroblastoma cell line were markedly increased by paraquat, and to a lesser extent by rotenone and maneb, but not by glyphosate. Rotenone also clearly increased endogenous α-syn levels in the SK-MEL-2 melanoma cell line. In the SH-SY5Y cell line, similar differences were observed in the α-syn adenovirus-transduced cells, with a higher increase of the A53T mutated protein. Paraquat markedly increased α-syn in the SK-MEL-2 adenovirus-transduced cell line, similarly for the wild-type or A53T proteins. The observed differences in the propensities of pesticides to increase α-syn levels are in agreement with numerous reports that indicate a potential role of exposure to certain pesticides in the development of Parkinson's disease. Our data support the hypothesis that pesticides can trigger some molecular events involved in this disease and also in malignant melanoma that consistently shows a significant but still unexplained association with Parkinson's disease.