FR58P1a; a new uncoupler of OXPHOS that inhibits migration in triple-negative breast cancer cells via Sirt1/AMPK/β1-integrin pathway

Abstract

Highly malignant triple-negative breast cancer (TNBC) cells rely mostly on glycolysis to maintain cellular homeostasis; however, mitochondria are still required for migration and metastasis. Taking advantage of the metabolic flexibility of TNBC MDA-MB-231 cells to generate subpopulations with glycolytic or oxidative phenotypes, we screened phenolic compounds containing an ortho-carbonyl group with mitochondrial activity and identified a bromoalkyl-ester of hydroquinone named FR58P1a, as a mitochondrial metabolism-affecting compound that uncouples OXPHOS through a protonophoric mechanism. In contrast to well-known protonophore uncoupler FCCP, FR58P1a does not depolarize the plasma membrane and its effect on the mitochondrial membrane potential and bioenergetics is moderate suggesting a mild uncoupling of OXPHOS. FR58P1a activates AMPK in a Sirt1-dependent fashion. Although the activation of Sirt1/AMPK axis by FR58P1a has a cyto-protective role, selectively inhibits fibronectin-dependent adhesion and migration in TNBC cells but not in non-tumoral MCF10A cells by decreasing β1-integrin at the cell surface. Prolonged exposure to FR58P1a triggers a metabolic reprograming in TNBC cells characterized by down-regulation of OXPHOS-related genes that promote cell survival but comprise their ability to migrate. Taken together, our results show that TNBC cell migration is susceptible to mitochondrial alterations induced by small molecules as FR58P1a, which may have therapeutic implications.

SIRT1 inhibits chemoresistance and cancer stemness of gastric cancer by initiating an AMPK/FOXO3 positive feedback loop

“…As metabolic sensors, SIRT1/AMPK signaling was shown to play important role in metabolism 33 . Recently, AMPK activated by SIRT1 is proven to act as a tumor suppressor in multiple solid tumors by inducing cell death, inhibiting cell migration, and attenuating hypoxia-induced chemoresistance 21,25,[34][35][36] . Our data demonstrated that silencing AMPKα partially reverses inhibitory role of SIRT1 in GC cells.…”

Complex Mitochondrial Dysfunction Induced by TPP+-Gentisic Acid and Mitochondrial Translation Inhibition by Doxycycline Evokes Synergistic Lethality in Breast Cancer Cells

“…To determine whether the inhibition of Complex I and αKGDHC by GA-TPP + C 10 has implications in the anticancer effect exhibited in BC cells, we added the exogenous metabolic substrate Pyr and the cell-penetrating intermediates mAsp and dm-KG, and the viability in the presence of GA-TPP + C 10 was evaluated at 48 h of exposure. Pyr addition was shown to rescue the antiproliferative effect only of ETC inhibitors [40][41][42] by lactate dehydrogenase-dependent NADH regeneration, and mAsp and dm-αKG addition rescued the carbon source for nucleotide biosynthesis and αKGDHC activity-dependent glutaminolysis [29,43,44]. As shown in Figure 4D,G, consistent with the αKGDHC activity assay, both dm-αKG and mAsp, but not Pyr, partially rescued the cytotoxic effect of GA-TPP + C 10 in the MCF7 and MDA-MB-231 cancer cells, suggesting that inhibition of αKGDHC activity is a relevant step for the promotion of mitochondrial dysfunction.…”

“…Next, GA-TPP + C 10 (10 µM) was added to the cells, and the cells were incubated for 5, 15, 30, and 60 min. Then, the cells were incubated with the fluorescent probes for 15 min protected from light, and the changes in fluorescence were measured by flow cytometry as previously described [29].…”

“…For analysis of glycolysis, the culture medium was replaced with assay medium (unbuffered DMEM without phenol red and with 4 mM glutamine, pH 7.4) 1 h before the assay. Glycolysis was evaluated by adding 10 mM glucose, 1 µM oligomycin, and 100 mM 2-deoxy-d-glucose (2-DG), as previously reported [29]. The oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) measurements were made with the specific excitation and emission wavelengths of the fluorescent probes for oxygen (532/650 nm) and protons (470/530 nm).…”

“…As shown in Figure 2A,B, a similar cytotoxic effect was observed in the presence of 5 and 25 mM glucose, but a discrete and significant increase in cell death was produced by glutamine deprivation. By completely substituting glucose for galactose, we generated BC cell subpopulations that exhibited high dependence on respiration and decreased involvement of glycolysis to meet the energy demand [29]. Under this condition, GA-TPP + C 10 produced extensive cell death.…”