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Dichloroacetate, a selective mitochondria-targeting drug for oral squamous cell carcinoma: a metabolic perspective of treatment.

Ruggieri V, Agriesti F, Scrima R, Laurenzana I, Perrone D, Tataranni T, Mazzoccoli C, Lo Muzio L, Capitanio N, Piccoli C - Oncotarget (2015)

Bottom Line: In this study we tested comparatively the effects of DCA on three different OSCC-derived cell lines, HSC-2, HSC-3, PE15.DCA treatment of the three OSCC cell lines, at pharmacological concentrations, resulted in stimulation of the respiratory activity and caused a remarkably distinctive pro-apoptotic/cytostatic effect on HSC-2 and HSC-3.This was accompanied with a large remodeling of the mitochondrial network, never documented before, leading to organelle fragmentation and with enhanced production of reactive oxygen species.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Pre-Clinical and Translational Research, IRCCS, CROB, Rionero in Vulture, Potenza, Italy.

ABSTRACT
Reprogramming of metabolism is a well-established property of cancer cells that is receiving growing attention as potential therapeutic target. Oral squamous cell carcinomas (OSCC) are aggressive and drugs-resistant human tumours displaying wide metabolic heterogeneity depending on their malignant genotype and stage of development. Dichloroacetate (DCA) is a specific inhibitor of the PDH-regulator PDK proved to foster mitochondrial oxidation of pyruvate. In this study we tested comparatively the effects of DCA on three different OSCC-derived cell lines, HSC-2, HSC-3, PE15. Characterization of the three cell lines unveiled for HSC-2 and HSC-3 a glycolysis-reliant metabolism whereas PE15 accomplished an efficient mitochondrial oxidative phosphorylation. DCA treatment of the three OSCC cell lines, at pharmacological concentrations, resulted in stimulation of the respiratory activity and caused a remarkably distinctive pro-apoptotic/cytostatic effect on HSC-2 and HSC-3. This was accompanied with a large remodeling of the mitochondrial network, never documented before, leading to organelle fragmentation and with enhanced production of reactive oxygen species. The data here presented indicate that the therapeutic efficacy of DCA may depend on the specific metabolic profile adopted by the cancer cells with those exhibiting a deficient mitochondrial oxidative phosphorylation resulting more sensitive to the drug treatment.

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Effect of DCA treatment on the metabolic profile of OSCC cells(A) Endogenous respiratory activities; light and dark blue bars show the OCRLEAK and the OCRATP respectively measured following exposure of OSCC cells to 4 mM DCA for 24 h. The values reported are fold-change calculated as the ratio of the OCR values in DCA-treated versus untreated cells and are the mean (± SEM) of three independent experiments. (**) P < 0.005, (***) P < 0.001 (#) P < 0.05 vs untreated. (B) Fold-changes of lactate release after 24 h-treatment with DCA; means (±SEM) of three independent experiments. (C) Fold-changes of the OxPhos/Glycolysis metabolic flux ratio (see Fig. 1E for explanation) in DCA-treated OSCC cells; means (±SEM) of three independent preparations assayed in parallel for OCRATP and lactate. (*) P < 0.05, (**) P < 0.01, (***) P < 0.005; (#) P <0.05, (##) P <0.01 vs untreated. (D) Fold-changes of the CIV activity in OSCC cells following DCA-treatment. The data reported are the mean (±SEM) of three independent experiments.
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Figure 3: Effect of DCA treatment on the metabolic profile of OSCC cells(A) Endogenous respiratory activities; light and dark blue bars show the OCRLEAK and the OCRATP respectively measured following exposure of OSCC cells to 4 mM DCA for 24 h. The values reported are fold-change calculated as the ratio of the OCR values in DCA-treated versus untreated cells and are the mean (± SEM) of three independent experiments. (**) P < 0.005, (***) P < 0.001 (#) P < 0.05 vs untreated. (B) Fold-changes of lactate release after 24 h-treatment with DCA; means (±SEM) of three independent experiments. (C) Fold-changes of the OxPhos/Glycolysis metabolic flux ratio (see Fig. 1E for explanation) in DCA-treated OSCC cells; means (±SEM) of three independent preparations assayed in parallel for OCRATP and lactate. (*) P < 0.05, (**) P < 0.01, (***) P < 0.005; (#) P <0.05, (##) P <0.01 vs untreated. (D) Fold-changes of the CIV activity in OSCC cells following DCA-treatment. The data reported are the mean (±SEM) of three independent experiments.

Mentions: Activation of PDH is expected to enhance the metabolic flux through the tricarboxylic cycle fueling the mitochondrial respiration [23]. Figure 3A shows that 4 mM DCA - a mildly cytotoxic concentration - caused, indeed, an increase of the resting endogenous OCR in all the three OSCC cell lines. This was partly contributed by enhanced OCRLEAK (light colored bars) and partly by enhanced OCRATP (dark colored bars). However, the relative largest effect of DCA was observed for the OCRATP in HSC-2 while that on PE15 resulted of modest entity. The impact of DCA treatment on lactate production did not cause significant changes in any of the three OSCC cell lines (Fig. 3B). Consequently, the OxPhos/Glycolysis flux ratio increased largely in HSC-2 and scantly in PE15 with an intermediate value for HSC-3 (Fig. 3C). Importantly, the activity of CIV was not significantly affected by the DCA treatment in any of the three OSCC cell lines (Fig. 3D), as well as the CIV protein content assessed by immunoblotting (not shown).


Dichloroacetate, a selective mitochondria-targeting drug for oral squamous cell carcinoma: a metabolic perspective of treatment.

Ruggieri V, Agriesti F, Scrima R, Laurenzana I, Perrone D, Tataranni T, Mazzoccoli C, Lo Muzio L, Capitanio N, Piccoli C - Oncotarget (2015)

Effect of DCA treatment on the metabolic profile of OSCC cells(A) Endogenous respiratory activities; light and dark blue bars show the OCRLEAK and the OCRATP respectively measured following exposure of OSCC cells to 4 mM DCA for 24 h. The values reported are fold-change calculated as the ratio of the OCR values in DCA-treated versus untreated cells and are the mean (± SEM) of three independent experiments. (**) P < 0.005, (***) P < 0.001 (#) P < 0.05 vs untreated. (B) Fold-changes of lactate release after 24 h-treatment with DCA; means (±SEM) of three independent experiments. (C) Fold-changes of the OxPhos/Glycolysis metabolic flux ratio (see Fig. 1E for explanation) in DCA-treated OSCC cells; means (±SEM) of three independent preparations assayed in parallel for OCRATP and lactate. (*) P < 0.05, (**) P < 0.01, (***) P < 0.005; (#) P <0.05, (##) P <0.01 vs untreated. (D) Fold-changes of the CIV activity in OSCC cells following DCA-treatment. The data reported are the mean (±SEM) of three independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 3: Effect of DCA treatment on the metabolic profile of OSCC cells(A) Endogenous respiratory activities; light and dark blue bars show the OCRLEAK and the OCRATP respectively measured following exposure of OSCC cells to 4 mM DCA for 24 h. The values reported are fold-change calculated as the ratio of the OCR values in DCA-treated versus untreated cells and are the mean (± SEM) of three independent experiments. (**) P < 0.005, (***) P < 0.001 (#) P < 0.05 vs untreated. (B) Fold-changes of lactate release after 24 h-treatment with DCA; means (±SEM) of three independent experiments. (C) Fold-changes of the OxPhos/Glycolysis metabolic flux ratio (see Fig. 1E for explanation) in DCA-treated OSCC cells; means (±SEM) of three independent preparations assayed in parallel for OCRATP and lactate. (*) P < 0.05, (**) P < 0.01, (***) P < 0.005; (#) P <0.05, (##) P <0.01 vs untreated. (D) Fold-changes of the CIV activity in OSCC cells following DCA-treatment. The data reported are the mean (±SEM) of three independent experiments.
Mentions: Activation of PDH is expected to enhance the metabolic flux through the tricarboxylic cycle fueling the mitochondrial respiration [23]. Figure 3A shows that 4 mM DCA - a mildly cytotoxic concentration - caused, indeed, an increase of the resting endogenous OCR in all the three OSCC cell lines. This was partly contributed by enhanced OCRLEAK (light colored bars) and partly by enhanced OCRATP (dark colored bars). However, the relative largest effect of DCA was observed for the OCRATP in HSC-2 while that on PE15 resulted of modest entity. The impact of DCA treatment on lactate production did not cause significant changes in any of the three OSCC cell lines (Fig. 3B). Consequently, the OxPhos/Glycolysis flux ratio increased largely in HSC-2 and scantly in PE15 with an intermediate value for HSC-3 (Fig. 3C). Importantly, the activity of CIV was not significantly affected by the DCA treatment in any of the three OSCC cell lines (Fig. 3D), as well as the CIV protein content assessed by immunoblotting (not shown).

Bottom Line: In this study we tested comparatively the effects of DCA on three different OSCC-derived cell lines, HSC-2, HSC-3, PE15.DCA treatment of the three OSCC cell lines, at pharmacological concentrations, resulted in stimulation of the respiratory activity and caused a remarkably distinctive pro-apoptotic/cytostatic effect on HSC-2 and HSC-3.This was accompanied with a large remodeling of the mitochondrial network, never documented before, leading to organelle fragmentation and with enhanced production of reactive oxygen species.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Pre-Clinical and Translational Research, IRCCS, CROB, Rionero in Vulture, Potenza, Italy.

ABSTRACT
Reprogramming of metabolism is a well-established property of cancer cells that is receiving growing attention as potential therapeutic target. Oral squamous cell carcinomas (OSCC) are aggressive and drugs-resistant human tumours displaying wide metabolic heterogeneity depending on their malignant genotype and stage of development. Dichloroacetate (DCA) is a specific inhibitor of the PDH-regulator PDK proved to foster mitochondrial oxidation of pyruvate. In this study we tested comparatively the effects of DCA on three different OSCC-derived cell lines, HSC-2, HSC-3, PE15. Characterization of the three cell lines unveiled for HSC-2 and HSC-3 a glycolysis-reliant metabolism whereas PE15 accomplished an efficient mitochondrial oxidative phosphorylation. DCA treatment of the three OSCC cell lines, at pharmacological concentrations, resulted in stimulation of the respiratory activity and caused a remarkably distinctive pro-apoptotic/cytostatic effect on HSC-2 and HSC-3. This was accompanied with a large remodeling of the mitochondrial network, never documented before, leading to organelle fragmentation and with enhanced production of reactive oxygen species. The data here presented indicate that the therapeutic efficacy of DCA may depend on the specific metabolic profile adopted by the cancer cells with those exhibiting a deficient mitochondrial oxidative phosphorylation resulting more sensitive to the drug treatment.

Show MeSH
Related in: MedlinePlus