Circadian regulation of clock gene expression and phospholipid biosynthesis in glioblastoma cells

SOSA ALDERETE LUCAS G; WAGNER, PAULA; GORNÉ, LUCAS D.; GUIDO MARIO E.

Congreso; LI Reunión Anual de la Sociedad Argentina de investigaciones en Bioquímica y Biología Molecular; 2015

Circadian clocks present even in immortalized cell lines, temporarily synchronized diverse physiological processes, among them the cell proliferation and apoptosis. Thus, disruption of circadian rhythms can alter cell cycle and cell growth to potentiate tumorigenesis. Here we analyzed whether the immortalized human glioblastoma T98G cells subject to proliferation (P) in the presence of serum, or maintained quiescent (Q) keep a functional clock, after synchronization, regulating gene expression and phospholipid (PL) metabolism under a circadian base. We examined the expression of clock genes (Bmal1, Per1, Rev-Erbα) and PL synthesizing enzyme genes (choline kinase α: Chokα and CTP:phosphoethanolamine cytidylyltransferase 2:Pcyt-2), and the metabolic labeling of PLs. For this, cells grown in 10% FBS-DMEM for 2-3 days were synchronized with a shock of 20 min dexamethasone (Dex, 100 nM) (time 0). Then, cells maintained with (P) or without FBS-DMEM (Q) for 48 h were collected at different times for further assays. Results showed that Bmal1, Per1, Rev-Erbα, Chokα and Pcyt-2 exhibited different temporal expression profiles, phases and amplitudes depending on the growth condition tested. Cell cultures also displayed a circadian oscillation in the labeling of 32P-PLs mainly when kept arrested. Overall, the temporal control of gene expression and metabolism persists in quiescent tumor cells and became more disorganized as proliferation progresses.