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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

Effects of Ras on HGF/SF-induced changes in tumor blood volumeMice bearing DA3 mammary adenocarcinoma tumors were treated either with vehicle alone (CMC 5%) or with FTS. Tumor blood volume was measured by CM ultrasound (As described in materials and methods) and the effect Ras inhibition on HGF/SF-induced blood flow increase was calculated. (A), an example of the effect of FTS on HGF/SF-induced hemodynamic changes. Tumor outlines were marked (top) and the changes in blood volume in the tumors were calculated. Maps depicting the change in tumor blood flow after HGF/SF administration compared to the baseline blood flow were generated (bottom). Yellow pixels depict increased blood volume after HGF/SF injection: black, no change; blue; decrease. (A1), vehicle-treated tumors showed an increase in blood volume after HGF/SF administration. Tumors treated (A2) with 10 mg/kg FTS or (A3) with 40 mg/kg FTS did not show this characteristic increase in blood volume. Quantitative analysis of basal tumor blood volume shows that it was not affected by either (B) long-term (5 times a week for 3 weeks, as described in materials and methods) or (C) short-term (single administration FTS) treatment with FTS (n = 33). In contrast, when the effect of FTS on HGF/SF-induced tumor blood volume was examined we demonstrate that vehicle treated mice displayed a 2 fold increase in tumor blood volume both in long and short term (D) treatments while long-term (E) treatment with either 10 mg/kg FTS (n = 18) or 40 mg/kg FTS (n = 21); P = 0.036 or P = 0.0002, respectively) (D), as well as by short-term FTS treatment, which was manifested as early as 8 hours after treatment was started (by 42%, n = 28, P = 0.035) (E) that was apparent also in mice treated with FTS 24 hours prior to imaging(47%, n=26, P = 0.028) (E).
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Figure 5: Effects of Ras on HGF/SF-induced changes in tumor blood volumeMice bearing DA3 mammary adenocarcinoma tumors were treated either with vehicle alone (CMC 5%) or with FTS. Tumor blood volume was measured by CM ultrasound (As described in materials and methods) and the effect Ras inhibition on HGF/SF-induced blood flow increase was calculated. (A), an example of the effect of FTS on HGF/SF-induced hemodynamic changes. Tumor outlines were marked (top) and the changes in blood volume in the tumors were calculated. Maps depicting the change in tumor blood flow after HGF/SF administration compared to the baseline blood flow were generated (bottom). Yellow pixels depict increased blood volume after HGF/SF injection: black, no change; blue; decrease. (A1), vehicle-treated tumors showed an increase in blood volume after HGF/SF administration. Tumors treated (A2) with 10 mg/kg FTS or (A3) with 40 mg/kg FTS did not show this characteristic increase in blood volume. Quantitative analysis of basal tumor blood volume shows that it was not affected by either (B) long-term (5 times a week for 3 weeks, as described in materials and methods) or (C) short-term (single administration FTS) treatment with FTS (n = 33). In contrast, when the effect of FTS on HGF/SF-induced tumor blood volume was examined we demonstrate that vehicle treated mice displayed a 2 fold increase in tumor blood volume both in long and short term (D) treatments while long-term (E) treatment with either 10 mg/kg FTS (n = 18) or 40 mg/kg FTS (n = 21); P = 0.036 or P = 0.0002, respectively) (D), as well as by short-term FTS treatment, which was manifested as early as 8 hours after treatment was started (by 42%, n = 28, P = 0.035) (E) that was apparent also in mice treated with FTS 24 hours prior to imaging(47%, n=26, P = 0.028) (E).

Mentions: We next examined the hemodynamic effects of Ras inhibition. Mice bearing DA3 mammary xenograft tumors (average volume, 10 mm3) were treated 5 times a week for 3 weeks with 40 mg/kg (high dose) or 10 mg/kg (low dose) of FTS dissolved in 0.5% CMC. Tumor blood volume was measured by US-CMI as described in Materials and Methods. In a previous study we showed that HGF/SF treatment in vivo leads to an increase of 200% to 300% in tumor blood volume [13]. In the present study we examined whether this phenomenon is abolished by the Ras inhibitor FTS. Treatment with FTS alone induced a slight, nonsignificant change in basal tumor blood flow (Fig. 5A). In mice treated with either low-dose (n = 18) or high-dose (n = 21) FTS, the HGF/SF-induced increase in tumor blood volume was significantly inhibited (P = 0.036;,P = 0.0002, respectively) (Fig. 5C). These results, by demonstrating that FTS inhibits the effect induced by HGF/SF on tumor blood volume, show that this induction is mediated through the Ras signaling cascade. Moreover, the higher dose of FTS used in this study led to the inhibition of blood volume in the tumor following HGF/SF administration, demonstrating the potency of the inhibitor.


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)

Effects of Ras on HGF/SF-induced changes in tumor blood volumeMice bearing DA3 mammary adenocarcinoma tumors were treated either with vehicle alone (CMC 5%) or with FTS. Tumor blood volume was measured by CM ultrasound (As described in materials and methods) and the effect Ras inhibition on HGF/SF-induced blood flow increase was calculated. (A), an example of the effect of FTS on HGF/SF-induced hemodynamic changes. Tumor outlines were marked (top) and the changes in blood volume in the tumors were calculated. Maps depicting the change in tumor blood flow after HGF/SF administration compared to the baseline blood flow were generated (bottom). Yellow pixels depict increased blood volume after HGF/SF injection: black, no change; blue; decrease. (A1), vehicle-treated tumors showed an increase in blood volume after HGF/SF administration. Tumors treated (A2) with 10 mg/kg FTS or (A3) with 40 mg/kg FTS did not show this characteristic increase in blood volume. Quantitative analysis of basal tumor blood volume shows that it was not affected by either (B) long-term (5 times a week for 3 weeks, as described in materials and methods) or (C) short-term (single administration FTS) treatment with FTS (n = 33). In contrast, when the effect of FTS on HGF/SF-induced tumor blood volume was examined we demonstrate that vehicle treated mice displayed a 2 fold increase in tumor blood volume both in long and short term (D) treatments while long-term (E) treatment with either 10 mg/kg FTS (n = 18) or 40 mg/kg FTS (n = 21); P = 0.036 or P = 0.0002, respectively) (D), as well as by short-term FTS treatment, which was manifested as early as 8 hours after treatment was started (by 42%, n = 28, P = 0.035) (E) that was apparent also in mice treated with FTS 24 hours prior to imaging(47%, n=26, P = 0.028) (E).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: Effects of Ras on HGF/SF-induced changes in tumor blood volumeMice bearing DA3 mammary adenocarcinoma tumors were treated either with vehicle alone (CMC 5%) or with FTS. Tumor blood volume was measured by CM ultrasound (As described in materials and methods) and the effect Ras inhibition on HGF/SF-induced blood flow increase was calculated. (A), an example of the effect of FTS on HGF/SF-induced hemodynamic changes. Tumor outlines were marked (top) and the changes in blood volume in the tumors were calculated. Maps depicting the change in tumor blood flow after HGF/SF administration compared to the baseline blood flow were generated (bottom). Yellow pixels depict increased blood volume after HGF/SF injection: black, no change; blue; decrease. (A1), vehicle-treated tumors showed an increase in blood volume after HGF/SF administration. Tumors treated (A2) with 10 mg/kg FTS or (A3) with 40 mg/kg FTS did not show this characteristic increase in blood volume. Quantitative analysis of basal tumor blood volume shows that it was not affected by either (B) long-term (5 times a week for 3 weeks, as described in materials and methods) or (C) short-term (single administration FTS) treatment with FTS (n = 33). In contrast, when the effect of FTS on HGF/SF-induced tumor blood volume was examined we demonstrate that vehicle treated mice displayed a 2 fold increase in tumor blood volume both in long and short term (D) treatments while long-term (E) treatment with either 10 mg/kg FTS (n = 18) or 40 mg/kg FTS (n = 21); P = 0.036 or P = 0.0002, respectively) (D), as well as by short-term FTS treatment, which was manifested as early as 8 hours after treatment was started (by 42%, n = 28, P = 0.035) (E) that was apparent also in mice treated with FTS 24 hours prior to imaging(47%, n=26, P = 0.028) (E).
Mentions: We next examined the hemodynamic effects of Ras inhibition. Mice bearing DA3 mammary xenograft tumors (average volume, 10 mm3) were treated 5 times a week for 3 weeks with 40 mg/kg (high dose) or 10 mg/kg (low dose) of FTS dissolved in 0.5% CMC. Tumor blood volume was measured by US-CMI as described in Materials and Methods. In a previous study we showed that HGF/SF treatment in vivo leads to an increase of 200% to 300% in tumor blood volume [13]. In the present study we examined whether this phenomenon is abolished by the Ras inhibitor FTS. Treatment with FTS alone induced a slight, nonsignificant change in basal tumor blood flow (Fig. 5A). In mice treated with either low-dose (n = 18) or high-dose (n = 21) FTS, the HGF/SF-induced increase in tumor blood volume was significantly inhibited (P = 0.036;,P = 0.0002, respectively) (Fig. 5C). These results, by demonstrating that FTS inhibits the effect induced by HGF/SF on tumor blood volume, show that this induction is mediated through the Ras signaling cascade. Moreover, the higher dose of FTS used in this study led to the inhibition of blood volume in the tumor following HGF/SF administration, demonstrating the potency of the inhibitor.

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