Cellular apoptosis: An alternative mechanism of action for caspofungin against Candida glabrata

Abstract

Background and Purpose: Although the mechanism of action for echinocandins is known, the physiological mechanisms by which these antifungal agents cause cell death via the classical apoptotic pathways are not well-defined yet. Regarding this, the present study aimed to evaluate the mechanisms of caspofungin-induced Candida glabrata cell death. Materials and Methods: For the purpose of the study, the minimum inhibitory concentration (MIC) of caspofungin against C. glabrata (ATCC 90030) was determined using the broth microdilution reference method (CLSI M27-A2 and M27-S4). The annexin V and propidium iodide staining was performed to determine the way through which caspofungin acts against C. glabrata (i.e., through the induction of apoptosis and/or necrosis). Additionally, the possible effect of caspofungin on inducing the expression of two apoptotic genes, namely MCA1 and NUC, was studied using the real-time polymerase chain reaction assay. Results: According to the obtained MIC value (0.5 μg/mL), C. glabrata, exposed to 0.25, 0.5, and 1 μg/mL of caspofungin, exhibited the features of late apoptosis/necrosis after 18 h of incubation. Furthermore, the use of 0.25, 0.5, and 1 μg/ml caspofungin induced apoptosis (early/late) in 14.67%, 17.04%, and 15.89% of the cells, respectively. The results showed a significant difference between the percentages of early-apoptotic cells at the three concentrations (p Conclusion: As the findings of the present study indicated, caspofungin promoted both necrosis and apoptosis of C. glabrata cells at concentrations higher than or equal to the MIC value.

Keywords

• candida glabrata
• caspofungin
• flow cytometry
• mca1
• nuc1