ABSTRACT
Title
Mithocondria defect and cisplatin resistance: relationships on ovarian cancer cells.
Authors
Montopoli M1, Bellanda M2, Ragazzi E1,Catanzaro D1, Froldi G1, Mammi S2, Caparrotta L1.
1Department of Pharmacology and Anaesthesiology, University of Padova, Largo E. Meneghetti 2, 35131 Padova, Italy.
2Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
1Department of Pharmacology and Anaesthesiology, University of Padova, Largo E. Meneghetti 2, 35131 Padova, Italy.
2Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
Abstract
The metabolism of tumors has fascinated cancer biologists since Warburg’s experiments in the 1920s, which showed that ascites tumor cells from the mouse were capable of unexpectedly high rates of glucose consumption and lactate secretion in the presence of oxygen (the Warburg effect).
The underlying biochemical and molecular mechanism of the Warburg’s effect remain unclear, but it is likely a combination of mitochondrial malfunction (Wallace 2005) oncogenic alteration (Dang, Semenza 1999), as well as adaptive responses to the tumour microenvironment (Gateby and Gillies 2004).We questioned the relevance of “metabolic reprogramming” in cisplatin-resistance, by studying mitochondrial function and metabolism in human ovary carcinoma cisplatin-resistant (C13) and -sensitive (2008) cell lines. C13 cells, in comparison 2008 cells, showed lower basal oxygen consumption (4.2±0.2 vs 6.5±0.7 fmol/cell/min, P<0.005) and lower basal transmembrane mitochondrial potential (ΔΨm) (18.7±1.5 vs 32.2±1 MFI P<0.001). Also C13 cells showed lower sensitivity to rotenone and oligomycin mitochondrial inhibitors. To further investigate the impact of mitochondria in the cisplatin- resistance, 2008 and C13 cells were depleted of their mitochondrial DNA (rho0-clones). Notably, the cytotoxicity of cisplatin was lower in 2008-rho0clones than in 2008 cells (IC50 3.56 µM and 0.72 µM) but similar between C13-rho0 and C13 cells (5.49 µM and 6.49 µM ). Next, the time-course of cell viability in glucose free-galactose medium, indicated that C13 cells were more strictly dependent on glucose, than 2008 cells. 1H-NMR spectroscopy evidenced higher basal content of intracellular GSH and mobile lipids (MLs) in C13 cells, as compared to 2008 cells, and Nile red staining confirmed the higher lipid accumulation, mainly within cytoplasmic droplets, in C13 cells. The findings allow to argue a “metabolic remodelling” of ovary carcinoma cells to a lipogenic phenotype, including alteration of mitochondrial function, as an advantageous mechanism to escape cisplatin-induced apoptosis. This hypothesis might be of interest to find new pharmacological targets to improve the clinical impact of platinum drugs.
Dang, Semenza. (1999). Trends Biochem Sci. 24:68-72.
Wallace. (2005) Annu Rev Genet. 39:359-407.
Gatenby, Gillies. (2004) Nat Rev Cancer. 4:891-9.
The underlying biochemical and molecular mechanism of the Warburg’s effect remain unclear, but it is likely a combination of mitochondrial malfunction (Wallace 2005) oncogenic alteration (Dang, Semenza 1999), as well as adaptive responses to the tumour microenvironment (Gateby and Gillies 2004).We questioned the relevance of “metabolic reprogramming” in cisplatin-resistance, by studying mitochondrial function and metabolism in human ovary carcinoma cisplatin-resistant (C13) and -sensitive (2008) cell lines. C13 cells, in comparison 2008 cells, showed lower basal oxygen consumption (4.2±0.2 vs 6.5±0.7 fmol/cell/min, P<0.005) and lower basal transmembrane mitochondrial potential (ΔΨm) (18.7±1.5 vs 32.2±1 MFI P<0.001). Also C13 cells showed lower sensitivity to rotenone and oligomycin mitochondrial inhibitors. To further investigate the impact of mitochondria in the cisplatin- resistance, 2008 and C13 cells were depleted of their mitochondrial DNA (rho0-clones). Notably, the cytotoxicity of cisplatin was lower in 2008-rho0clones than in 2008 cells (IC50 3.56 µM and 0.72 µM) but similar between C13-rho0 and C13 cells (5.49 µM and 6.49 µM ). Next, the time-course of cell viability in glucose free-galactose medium, indicated that C13 cells were more strictly dependent on glucose, than 2008 cells. 1H-NMR spectroscopy evidenced higher basal content of intracellular GSH and mobile lipids (MLs) in C13 cells, as compared to 2008 cells, and Nile red staining confirmed the higher lipid accumulation, mainly within cytoplasmic droplets, in C13 cells. The findings allow to argue a “metabolic remodelling” of ovary carcinoma cells to a lipogenic phenotype, including alteration of mitochondrial function, as an advantageous mechanism to escape cisplatin-induced apoptosis. This hypothesis might be of interest to find new pharmacological targets to improve the clinical impact of platinum drugs.
Dang, Semenza. (1999). Trends Biochem Sci. 24:68-72.
Wallace. (2005) Annu Rev Genet. 39:359-407.
Gatenby, Gillies. (2004) Nat Rev Cancer. 4:891-9.