Calorimetric and spectroscopic investigation of the interaction of chemotherapeutic agent carboplatin with sphingomyelin lipids

Carboplatin (CAR) is a chemo-therapeutic agent which interacts with DNA to interfer its repair, and thereby to induce apoptosis. Since CAR acts inside cell, its inevitable interaction with membrane lipids directly affects its efficacy. In the current work, we investigated the interaction profile of CAR with sphingomyelin (SM) lipids, which plays key role in different cellular functions, particularly important in cancer. By utilizing Differential Scanning Calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy, the effects of different concentrations of CAR (1-5-10-20-30 mol%) on phase transition temperature (Tm), enthalpy (Delta H), cooperativity (CU), lipid order, lipid fluidity and the strength of hydrogen bonding of SM lipids were monitored. The results revealed that CAR caused a decrease in Tm, Delta H, CU, lipid order, but an increase in hydrogen state of hydrophilic region of SM lipids. On the other hand, a slight decrement in fluidity solely at 30 mol% was monitored. The findings revealed that CAR incorporates into SM bilayers by binding to acyl chains and hydrophilic parts of lipids. In sum, the results may represent valuable information about the effect of CAR on biophysical properties of SM lipids, which may reflect its behavior and action in real biological systems.

Automated summary

The study revealed that carboplatin decreased phase transition temperature, enthalpy, cooperativity, and lipid order of sphingomyelin lipids, but increased the hydrogen state of the hydrophilic region. It only caused a slight decrease in lipid fluidity at a higher concentration. Carboplatin incorporates into sphingomyelin bilayers by binding to acyl chains and hydrophilic parts of lipids.