Cytosolic Ca2+ dynamics in normal and pathological human cells

VIGIL, MAXIMILIANO; ONTIVEROS, M; RINALDI, D.E; ESPELT, VICTORIA; MANGIALAVORI, I. .; REY, O; ROSSI, J.P.; FERREIRA GOMES, M

La Plata

Congreso; XLVII Reunión Anual de la Sociedad Argentina de Biofísica; 2018

Calcium homeostasis is highly regulated in cells. Free cytosolic Ca2+ ([Ca2+]c), which acts as a second messenger, is crucial for a wide range of biological functions. All cells must maintain a low concentration of [Ca2+]c (~100 nM) to maintain viability, while using their increase as a versatile signaling pathway. Prolonged intracellular elevation of Ca2 + can trigger cell death. Evidence shows that the calcium homeostasis is altered in cancer cells and the alteration is involved in tumor onset, angiogenesis, progression and metastasis. In this work, we characterized the dynamics of [Ca2+]c for different neoplastic cell lines SW480, CaCo and HepG2, and compare them with the normal dynamics of HEK293T cells.The dynamics of [Ca2+]c were examined by the Ca2+ release from endoplasmic reticulum (ER) in the different cell lines. The cells were loaded with fluo4 or fura2 to measure [Ca2+]c and followed the fluorescence in real time before and after the addition of thapsigargin, an inhibitor of the sarcoplasmic reticulum calcium pump. The dynamics of [Ca2+]c in HEK293T cells showed a maximum peak followed by an exponential decrease to the basal level. On the other hand, in the colon carcinoma cells, SW480 and CaCo, the peaks returned to a higher steady-state. In HepG2 cells, no peaks were observed but an exponential increase to a maximal steady-state.Then, we studied the effect of quercetin on the dynamics of [Ca2+]c. Quercetin is a flavonoid with antitumoral properties, which inhibits calcium channels and pumps, altering the intracellular calcium homeostasis. We observed that quercetin altered the dynamics of [Ca2+]c in SW480, CaCo, and HepG2 cells, whereas in HEK293T cells did not change. Ours results suggest that quercetin could affect the calcium homeostasis in pathogenic cells by inhibition of Ca2+ transport systems.This work reveals that the study of dynamics of [Ca2+]c could be used for characterizing differences in calcium homeostasis in pathogenic cells.Acknowledgments. This work was supported with grants of ANPCYT, CONICET and UBACYT.