Assessing the impact of Fasciola hepatica excretory-secretory antigens on A549 cells: viability, apoptosis, ROS, and...

Lung cancer is one of the most fatal malignancies. The connection between parasitic infections and cancer development has become an interesting subject. This study evaluates the impact of Fasciola hepatica (F. hepatica) excretory-secretory (ES) antigens on various cellular processes, including cell viability, apoptosis, cell cycle progression, reactive oxygen species (ROS) production, and the expression of markers such as SOX-9, β-catenin, CD44, and CD133 in A549 lung cancer cells.

F. hepatica was collected from sheep livers, washed, and cultured in RPMI medium for ES antigens preparation. A549 lung cancer cells were cultured and treated with varying concentrations of ES antigens. The cytotoxic effects of ES antigens on A549 cells were assessed with the MTT test. Apoptosis, necrosis, cell cycle, and ROS levels were quantified using flow cytometry. Real-time PCR was used to analyse the expression levels of SOX-9, β-catenin, CD44, and CD133 genes.

The protein concentration of the antigens was between 60 and 270 µg/ml after 24 and 48 h. The MTT cytotoxicity assay revealed a complex dose-dependent relationship between F. hepatica ES antigens and cancer cell viability. Lower concentrations (45 to 150 µg/mL) of these antigens were associated with decreased cancer cell viability, whereas higher concentrations (165 to 240 µg/mL) unexpectedly enhanced cell survival. Treatment with 60, 90, and 255 µg/mL of ES antigen enhanced apoptosis, whereas 135 and 195 µg/mL reduced apoptosis rates compared with the control group. There was a significant reduction in the population of cells at the S phase of the cell cycle at 135 and 195 µg/mL of ES antigen. In comparison, an increase in the population of cells in the S phase was observed at 255 µg/mL, suggesting that antigen concentration affects cell cycle progression and apoptosis. Some concentrations (195 and 255 µg/mL) of ES antigen were associated with increased expression of stem cell markers, including CD133, SOX9, and β-catenin. Notably, increased production of reactive oxygen species (ROS) was observed across all concentrations.

F.hepatica ES antigens may play a dual role in lung cancer cells. These antigens may possess properties that might potentially protect cancer cells from apoptosis. Conversely, in different doses, the antigens may induce cytotoxic effects, increasing cell death. This controversial data highlights the complexity of F. hepatica antigen interactions with cancer cells, which may be related to time and dose-dependency of their antigen treatment.