Comparison of NMR lipid profiles in mitotic arrest and apoptosis as indicators of paclitaxel resistance in cervical cell lines

Abstract

This study aimed to characterize changes in lipid saturation using magnetic resonance spectroscopy of sensitive (HeLa) and resistant (C33A; Me180) cervical cancer cell lines following exposure to paclitaxel to explore lipid profiles as biomarkers of drug resistance. Spectra were acquired at 11.74 T. Flow cytometry, electron, and confocal microscopy assessed cellular morphology. Western blots assessed cytoplasmic phospholipase A 2 , fatty acid synthase, and acyl-CoA synthetase1 expression. After 24 h of paclitaxel exposure, >60% of cells showed mitotic arrest. At 48 h, HeLa cells showed apoptosis while C33A/Me180 cells showed normal morphology indicating resistance. MRvisible lipids increased significantly in all lines at 24 h with further increases at 48 h; resistant lines showed smaller increases than HeLa. Cytoplasmic phospholipase A 2 and fatty acid synthase levels were unchanged at 24 h and dropped at 48 h in HeLa; acyl-CoA synthetase1 was higher in Me180/C33A than in HeLa controls but did not increase significantly. The percentage of cells displaying lipid droplets increased significantly at 24 and 48 h in all lines; droplet size increased only in HeLa cells. Droplet number was >3-43 greater in apoptotic compared with mitotic-arrested cells. Apoptotic cells accumulate unsaturated fatty acids in large (relative to control) droplets; resistant lines accumulated smaller droplets with less triglycerides. Magn Reson Med 68:369-377,

Increased unsaturation of lipids in cytoplasmic lipid droplets in DAOY cancer cells in response to cisplatin treatment

“…Extracts of LDs show an increase in unsaturated fatty acids which reflect those seen in HR-MAS of whole DAOY cells undergoing apoptosis consistent with the 1 H NMR signal arising from the lipids pool present in LDs. The latter observation is in agreement with previous cell (Quintero et al 2007; Zietkowski et al 2012) and brain tumour (Griffin et al 2003; Hakumaki et al 1999) studies. These changes in lipid composition are not detected in lipid extracts from whole cells showing that the lipids from non-LD sources (such as membranes) dilute observations from a specific pool of 1 H NMR visible species.…”

“…Two mechanisms have been proposed to contribute to the increased unsaturated 1 H NMR detectable lipids in apoptotic cells: (a) repartitioning from the cellular membrane degradation (Griffin et al 2003) and (b) de novo synthesis of lipids. (Boren and Brindle 2012; Zietkowski et al 2012). …”

Metabolic Markers of MG-63 Osteosarcoma Cell Line Response to Doxorubicin and Methotrexate Treatment: Comparison to Cisplatin

“…Increased average chain length and unsaturation degree, as clearly confirmed here for MG-63 cells exposed to cDDP, have also been suggested as apoptosis signs. 13,45 The PUFA structures, detected here for the first time in cDDP-treated OS cells through the  CHCH 2 CH resonance (60% increased upon cDDP treatment for 48 h), have been specifically suggested as preapoptotic functional lipid mediators in the cell death pathway. 17 Remarkably, MG-63 cells exposed to DOX or MTX failed to exhibit an increase in neutral lipids main resonances, CH 3 and (CH 2 ) n (faint decreases being even suggested, Figure 5), but showed increases in the PUFA resonance (particularly in the case of DOX).…”

Recent Advances in the Molecular Imaging of Programmed Cell Death: Part II—Non–Probe-Based MRI, Ultrasound, and Optical Clinical Imaging Techniques

“…The droplets are also associated with an accumulation of triacylglycerides generated by apoptosis-induced phospholipase-A 2 activity and ceramide released by the hydrolysis of sphingomyelin by the membrane enzyme, sphingomyelinase. Because lipid droplets can be seen in both apoptosis and necrosis, the specificity of the signals observed at 2.8 and 5.4 ppm is a potential problem (4).…”