Effect of polypeptide bCAT combined with caspofungin on hypha and mature biofilm in Candida albicans

Abstract

Objective To investigate the effect and mechanism of chromogranin (CGA)-derived polypeptide bCAT combined with caspofungin (CAS) on hypha and mature biofilm in Candida albicans (C. albicans). Methods Standard strain ATCC 10231 of C. albicans was employed as the study objective. The changes of biofilm metabolic activity after bCAT and CAS treatment alone or combined together (RPMI1640 as control group) were detected by XTT assay, and the results were calculated for the minimal biofilm inhibitory concentration (MBIC50). The expression of agglutinin-like sequence 3 (ALS3) was detected by RT-PCR, and the production of reactive oxygen content (ROS) was observed by DCFH-DA. SYTO9/PI staining was used to detect the fungal membrane permeability. Results The MBIC50 after bCAT and CAS treatment was 3 105 and 128 μg/mL, respectively. And the MBIC50 of bCAT combined with CAS was decreased to 776 μg/mL and 4 μg/mL, respectively. The expression of ALS3 in the bCAT+CAS group was (1.71±0.65)%, which had statistical differences from that of the control, bCAT (776 μg/mL) and CAS (4 μg/mL) groups (P < 0.05). The ROS content was (428.96±47.67)%, with significant difference compared with the control, bCAT (776 μg/mL) and CAS (4 μg/mL) groups (P < 0.05). There were more dead C. albicans in mature biofilm in the bCAT+CAS group, and the fungal hypha were decreased significantly. Conclusion CGA-derived polypeptide bCAT combined with CAS has the synergistic anti-mature biofilm effect, and the mechanism may be associated with decreased expression of ALS3 and inhibition of hypha formation, and oxidative damage caused by increased ROS content.

Keywords

• chromogranin a
• candida albicans
• biofilm
• caspofungin
• synergistic effect