Limits...
Interplay Between HGF/SF-Met-Ras Signaling, Tumor Metabolism and Blood Flow as a Potential Target for Breast Cancer Therapy.

Natan S, Tsarfaty G, Horev J, Haklai R, Kloog Y, Tsarfaty I - Oncoscience (2013)

Bottom Line: In vitro, HGF/SF-activated Met increased Ras activity, Erk phosphorylation, cell motility and glucose uptake, but did not affect ATP.FTS inhibited basal and HGF/SF-induced signaling and cell motility, while further increasing glucose uptake and inhibiting ATP production.FTS did not affect basal blood-flow but abolished the HGF/SF effect.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University ; This work was done in partial fulfillment of the requirements for the Ph.D. degree of S.N.

ABSTRACT
High glucose uptake and increase blood flow is a characteristic of most metastatic tumors. Activation of Ras signaling increases glycolytic flux into lactate, de novo nucleic acid synthesis and uncoupling of ATP synthase from the proton gradient. Met tyrosine kinase receptor signaling upon activation by its ligand, hepatocyte growth factor/scatter factor (HGF/SF), increases glycolysis, oxidative phosporylation, oxygen consumption, and tumor blood volume. Ras is a key factor in Met signaling. Using the Ras inhibitor S-trans,trans-farnesylthiosalicylic acid (FTS), we investigated interplay between HGF/SF-Met-Ras signaling, metabolism, and tumor blood-flow regulation. In vitro, HGF/SF-activated Met increased Ras activity, Erk phosphorylation, cell motility and glucose uptake, but did not affect ATP. FTS inhibited basal and HGF/SF-induced signaling and cell motility, while further increasing glucose uptake and inhibiting ATP production. In vivo, HGF/SF rapidly increased tumor blood volume. FTS did not affect basal blood-flow but abolished the HGF/SF effect. Our results further demonstrate the complex interplay between growth-factor-receptor signaling and cellular and tumor metabolism, as reflected in blood flow. Inhibition of Ras signaling does not affect glucose consumption or basal tumor blood flow but dramatically decreases ATP synthesis and the HGF/SF induced increase in tumor blood volume. These findings demonstrate that the HGF/SF-Met-Ras pathway critically influences tumor-cell metabolism and tumor blood-flow regulation. This pathway could potentially be used to individualize tumor therapy based on functional molecular imaging, and for combined signaling/anti-metabolic targeted therapy.

No MeSH data available.


Related in: MedlinePlus

Effect of Ras inhibition on HGF/SF-induced glucose uptake and on ATP synthesis in tumor cells in vitroDA3 cells treated with vehicle (DMSO 0.1% control) or with HGF/SF (80ng/mL), 5 μM FTS, 5 μM FTS +HGF/SF.HGF/SF. (A), the cells were then incubated with the fluorescent glucose analog 2NDBG. Fluorescence was measured by confocal laser scanning microscopy (CLSM) and quantified by ImageJ. HGF/SF and FTS significantly increased the uptake of glucose separately and also in combination (*,P < 0.0001). (B), representative confocal images of DA3 cells treated with: 1. vehicle alone, 2. HGF/SF, 3. FTS, 4.HGF/SF and FTS. (C), despite the increase in glucose uptake, HGF/SF did not increase ATP production relative to baseline in control (vehicle-untreated) cells, yet FTS decreased ATP levels significantly (*, P<0.0001) and HGF/SF negated this effect (as seen in cells treated with both HGF/SF and FTS) (**, P < 0.0001).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4295761&req=5

Figure 2: Effect of Ras inhibition on HGF/SF-induced glucose uptake and on ATP synthesis in tumor cells in vitroDA3 cells treated with vehicle (DMSO 0.1% control) or with HGF/SF (80ng/mL), 5 μM FTS, 5 μM FTS +HGF/SF.HGF/SF. (A), the cells were then incubated with the fluorescent glucose analog 2NDBG. Fluorescence was measured by confocal laser scanning microscopy (CLSM) and quantified by ImageJ. HGF/SF and FTS significantly increased the uptake of glucose separately and also in combination (*,P < 0.0001). (B), representative confocal images of DA3 cells treated with: 1. vehicle alone, 2. HGF/SF, 3. FTS, 4.HGF/SF and FTS. (C), despite the increase in glucose uptake, HGF/SF did not increase ATP production relative to baseline in control (vehicle-untreated) cells, yet FTS decreased ATP levels significantly (*, P<0.0001) and HGF/SF negated this effect (as seen in cells treated with both HGF/SF and FTS) (**, P < 0.0001).

Mentions: To gain further knowledge of the effects of HGF/SF and Ras inhibition by FTS on tumor cell metabolism, we measured glucose uptake and ATP synthesis in cultured DA3 cells. The cells (starved of serum) were treated with HGF/SF (80 ng/mL for 24 hours) and/or FTS (5 μM for 4 hours) (Fig. 2A). Glucose uptake was increased by all 3 treatments compared to the control: the increase was 69% with HGF/SF alone, 85% with FTS alone (P < 0.0001), and 126% with combined treatment with HGF/SF and FTS (P = 0.03). In contrast to glucose uptake ATP levels were not affected by treatment with HGF/SF, either alone or in combination with FTS, while treatment with FTS alone decreased ATP levels by 24% (P < 0.0001) (Fig. 2B). These results demonstrated the uncoupling in these tumor cells between the effects FTS on glucose uptake and on ATP.


Interplay Between HGF/SF-Met-Ras Signaling, Tumor Metabolism and Blood Flow as a Potential Target for Breast Cancer Therapy.

Natan S, Tsarfaty G, Horev J, Haklai R, Kloog Y, Tsarfaty I - Oncoscience (2013)

Effect of Ras inhibition on HGF/SF-induced glucose uptake and on ATP synthesis in tumor cells in vitroDA3 cells treated with vehicle (DMSO 0.1% control) or with HGF/SF (80ng/mL), 5 μM FTS, 5 μM FTS +HGF/SF.HGF/SF. (A), the cells were then incubated with the fluorescent glucose analog 2NDBG. Fluorescence was measured by confocal laser scanning microscopy (CLSM) and quantified by ImageJ. HGF/SF and FTS significantly increased the uptake of glucose separately and also in combination (*,P < 0.0001). (B), representative confocal images of DA3 cells treated with: 1. vehicle alone, 2. HGF/SF, 3. FTS, 4.HGF/SF and FTS. (C), despite the increase in glucose uptake, HGF/SF did not increase ATP production relative to baseline in control (vehicle-untreated) cells, yet FTS decreased ATP levels significantly (*, P<0.0001) and HGF/SF negated this effect (as seen in cells treated with both HGF/SF and FTS) (**, P < 0.0001).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4295761&req=5

Figure 2: Effect of Ras inhibition on HGF/SF-induced glucose uptake and on ATP synthesis in tumor cells in vitroDA3 cells treated with vehicle (DMSO 0.1% control) or with HGF/SF (80ng/mL), 5 μM FTS, 5 μM FTS +HGF/SF.HGF/SF. (A), the cells were then incubated with the fluorescent glucose analog 2NDBG. Fluorescence was measured by confocal laser scanning microscopy (CLSM) and quantified by ImageJ. HGF/SF and FTS significantly increased the uptake of glucose separately and also in combination (*,P < 0.0001). (B), representative confocal images of DA3 cells treated with: 1. vehicle alone, 2. HGF/SF, 3. FTS, 4.HGF/SF and FTS. (C), despite the increase in glucose uptake, HGF/SF did not increase ATP production relative to baseline in control (vehicle-untreated) cells, yet FTS decreased ATP levels significantly (*, P<0.0001) and HGF/SF negated this effect (as seen in cells treated with both HGF/SF and FTS) (**, P < 0.0001).
Mentions: To gain further knowledge of the effects of HGF/SF and Ras inhibition by FTS on tumor cell metabolism, we measured glucose uptake and ATP synthesis in cultured DA3 cells. The cells (starved of serum) were treated with HGF/SF (80 ng/mL for 24 hours) and/or FTS (5 μM for 4 hours) (Fig. 2A). Glucose uptake was increased by all 3 treatments compared to the control: the increase was 69% with HGF/SF alone, 85% with FTS alone (P < 0.0001), and 126% with combined treatment with HGF/SF and FTS (P = 0.03). In contrast to glucose uptake ATP levels were not affected by treatment with HGF/SF, either alone or in combination with FTS, while treatment with FTS alone decreased ATP levels by 24% (P < 0.0001) (Fig. 2B). These results demonstrated the uncoupling in these tumor cells between the effects FTS on glucose uptake and on ATP.

Bottom Line: In vitro, HGF/SF-activated Met increased Ras activity, Erk phosphorylation, cell motility and glucose uptake, but did not affect ATP.FTS inhibited basal and HGF/SF-induced signaling and cell motility, while further increasing glucose uptake and inhibiting ATP production.FTS did not affect basal blood-flow but abolished the HGF/SF effect.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University ; This work was done in partial fulfillment of the requirements for the Ph.D. degree of S.N.

ABSTRACT
High glucose uptake and increase blood flow is a characteristic of most metastatic tumors. Activation of Ras signaling increases glycolytic flux into lactate, de novo nucleic acid synthesis and uncoupling of ATP synthase from the proton gradient. Met tyrosine kinase receptor signaling upon activation by its ligand, hepatocyte growth factor/scatter factor (HGF/SF), increases glycolysis, oxidative phosporylation, oxygen consumption, and tumor blood volume. Ras is a key factor in Met signaling. Using the Ras inhibitor S-trans,trans-farnesylthiosalicylic acid (FTS), we investigated interplay between HGF/SF-Met-Ras signaling, metabolism, and tumor blood-flow regulation. In vitro, HGF/SF-activated Met increased Ras activity, Erk phosphorylation, cell motility and glucose uptake, but did not affect ATP. FTS inhibited basal and HGF/SF-induced signaling and cell motility, while further increasing glucose uptake and inhibiting ATP production. In vivo, HGF/SF rapidly increased tumor blood volume. FTS did not affect basal blood-flow but abolished the HGF/SF effect. Our results further demonstrate the complex interplay between growth-factor-receptor signaling and cellular and tumor metabolism, as reflected in blood flow. Inhibition of Ras signaling does not affect glucose consumption or basal tumor blood flow but dramatically decreases ATP synthesis and the HGF/SF induced increase in tumor blood volume. These findings demonstrate that the HGF/SF-Met-Ras pathway critically influences tumor-cell metabolism and tumor blood-flow regulation. This pathway could potentially be used to individualize tumor therapy based on functional molecular imaging, and for combined signaling/anti-metabolic targeted therapy.

No MeSH data available.


Related in: MedlinePlus