Secretory Phospholipase A2 (sPLA2) Isozymes as Potential Targets in Tobacco Condensate-induced Colon Damage

Aims To find out the role of secretory phospholipase A2 (sPLA(2)) isozymes as potential targets in tobacco condensate-induced colon damage. Background The effects of cigarette smoke condensate (CSC) and the molecular mechanisms involved in the regulation of phospholipase A2 (PLA(2)) and its isozymes in colon cells, which are still unclear and emerging, are studied. Objectives The study aimed to check the effect of CSC on cell viability and reactive oxygen species (ROS) and superoxide. Also, the effect of CSC on gene expression of different secretory phospholipase A2 (sPLA(2)) was evaluated. Moreover, the impact of inhibition of sPLA(2) on various cell properties i.e. cell viability, cell proliferation, membrane damage and free radicals' generation is also studied. Methods CSC-induced changes were evaluated in cell viability by MTT assay, followed by the evaluation of membrane modulation by flow cytometry, free radical generation by fluorescent dyes, PLA(2) isoforms gene expression patterns and their suppression by small interfering RNA (siRNA) studied in HCT-15 male and HT-29 female colon cells. Results Our results demonstrate that HCT-15 and HT-29 cells treated with CSC significantly reduced the cell viability by 50% within 48 h and significantly enhanced the total reactive oxygen species (ROS) by 2 to 10-fold, and mitochondrial ROS (mtROS) and superoxide radicals (SOR) by 2-fold each. Treatment with CSC significantly unregulated secretory phospholipase A2 (sPLA(2)) IID group and down-regulated IB and cytosolic phospholipase (cPLA(2)) IVA groups in HCT-15 cells without affecting them in HT-29 cells. Silencing the sPLA(2) IID group results in an increase in cell viability and a decrease in ROS. Silencing the PLA(2) IVA gene in the HCT-15 cells showed a reduced expression which had no impact on the CSC-induced cell proliferation, membrane damage and free radicals (ROS, mtROS, and SOR) generation. Conclusion Therefore, identifying cell-specific sPLA(2) isozymes seems to play a key role in controlling the ROS-induced damage by CSC and helps develop specific therapeutic strategies.

Automated summary

The study aims to investigate the potential role of secretory phospholipase A2 (sPLA(2)) isozymes in tobacco condensate-induced colon damage. The effects of cigarette smoke condensate (CSC) on cell viability, reactive oxygen species (ROS), and gene expression of different sPLA(2) were evaluated. The findings suggest that specific sPLA(2) isozymes play a key role in controlling CSC-induced damage and may aid in the development of targeted therapeutic strategies.