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Geraniol Suppresses Angiogenesis by Downregulating Vascular Endothelial Growth Factor (VEGF)/VEGFR-2 Signaling.

Wittig C, Scheuer C, Parakenings J, Menger MD, Laschke MW - PLoS ONE (2015)

Bottom Line: In vitro, geraniol reduced the migratory activity of endothelial-like eEND2 cells.In addition, geraniol significantly reduced vascular sprout formation in a rat aortic ring assay.Immunohistochemical analyses confirmed a decreased number of Ki67-positive cells and CD31-positive microvessels with reduced VEGFR-2 expression within geraniol-treated tumors.

View Article: PubMed Central - PubMed

Affiliation: Institute for Clinical & Experimental Surgery, University of Saarland, Homburg/Saar, Germany.

ABSTRACT
Geraniol exerts several direct pharmacological effects on tumor cells and, thus, has been suggested as a promising anti-cancer compound. Because vascularization is a major precondition for tumor growth, we analyzed in this study the anti-angiogenic action of geraniol. In vitro, geraniol reduced the migratory activity of endothelial-like eEND2 cells. Western blot analyses further revealed that geraniol downregulates proliferating cell nuclear antigen (PCNA) and upregulates cleaved caspase-3 (Casp-3) expression in eEND2 cells. Moreover, geraniol blocked vascular endothelial growth factor (VEGF)/VEGFR-2 signal transduction, resulting in a suppression of downstream AKT and ERK signaling pathways. In addition, geraniol significantly reduced vascular sprout formation in a rat aortic ring assay. In vivo, geraniol inhibited the vascularization of CT26 tumors in dorsal skinfold chambers of BALB/c mice, which was associated with a smaller tumor size when compared to vehicle-treated controls. Immunohistochemical analyses confirmed a decreased number of Ki67-positive cells and CD31-positive microvessels with reduced VEGFR-2 expression within geraniol-treated tumors. Taken together, these findings indicate that geraniol targets multiple angiogenic mechanisms and, therefore, is an attractive candidate for the anti-angiogenic treatment of tumors.

No MeSH data available.


Related in: MedlinePlus

Geraniol action on viability of eEND2 cells.A, B: Cell viability (% of control) (A) and cytotoxicity (% of control– 100%) (B) of eEND2 cells, which were exposed for 24h to different doses (50–400μM; n = 4) of geraniol, Triton X-100 as cytotoxic control (TX) or vehicle (control; n = 4), as assessed by WST-1 assay (A) and LDH release assay (B). Means ± SEM. *P<0.05 vs. control. C-E: Representative graphs from flow cytometry analyses of PI- and annexin V-stained eEND2 cells, which were exposed for 24h to 200μM (D; n = 4) and 400μM (E; n = 4) geraniol or vehicle (control; C; n = 4). F-H: Viable cells (= PI-negative/annexin V-negative; %) (F), necrotic cells (= PI-positive/annexin V-negative; %) and apoptotic cells (PI-negative/annexin V-positive and PI-positive/annexin V-positive; %), as assessed by flow cytometry. Means ± SEM. *P<0.05 vs. control.
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pone.0131946.g001: Geraniol action on viability of eEND2 cells.A, B: Cell viability (% of control) (A) and cytotoxicity (% of control– 100%) (B) of eEND2 cells, which were exposed for 24h to different doses (50–400μM; n = 4) of geraniol, Triton X-100 as cytotoxic control (TX) or vehicle (control; n = 4), as assessed by WST-1 assay (A) and LDH release assay (B). Means ± SEM. *P<0.05 vs. control. C-E: Representative graphs from flow cytometry analyses of PI- and annexin V-stained eEND2 cells, which were exposed for 24h to 200μM (D; n = 4) and 400μM (E; n = 4) geraniol or vehicle (control; C; n = 4). F-H: Viable cells (= PI-negative/annexin V-negative; %) (F), necrotic cells (= PI-positive/annexin V-negative; %) and apoptotic cells (PI-negative/annexin V-positive and PI-positive/annexin V-positive; %), as assessed by flow cytometry. Means ± SEM. *P<0.05 vs. control.

Mentions: In a first step we examined the effect of different doses of geraniol on the viability of eEND2 cells by means of a WST-1 assay. We found that geraniol doses of 50–400μM do not affect the viability of the cells (Fig 1A). Moreover, treatment of the cells in this dose range only showed a significant LDH release into the culture medium at a geraniol concentration of 400μM (Fig 1B). However, the extent of this LDH release (~10%) was rather low. These findings were confirmed by flow cytometric analyses of PI- and annexin V-stained eEND2 cells, which were exposed to 200 or 400μM geraniol (Fig 1C–1H). Once again, they exhibited a high fraction of viable cells (>90%) (Fig 1F). Besides, we found that geraniol dose-dependently induced necrotic and apoptotic cell death in a small fraction of cells (Fig 1G and 1H).


Geraniol Suppresses Angiogenesis by Downregulating Vascular Endothelial Growth Factor (VEGF)/VEGFR-2 Signaling.

Wittig C, Scheuer C, Parakenings J, Menger MD, Laschke MW - PLoS ONE (2015)

Geraniol action on viability of eEND2 cells.A, B: Cell viability (% of control) (A) and cytotoxicity (% of control– 100%) (B) of eEND2 cells, which were exposed for 24h to different doses (50–400μM; n = 4) of geraniol, Triton X-100 as cytotoxic control (TX) or vehicle (control; n = 4), as assessed by WST-1 assay (A) and LDH release assay (B). Means ± SEM. *P<0.05 vs. control. C-E: Representative graphs from flow cytometry analyses of PI- and annexin V-stained eEND2 cells, which were exposed for 24h to 200μM (D; n = 4) and 400μM (E; n = 4) geraniol or vehicle (control; C; n = 4). F-H: Viable cells (= PI-negative/annexin V-negative; %) (F), necrotic cells (= PI-positive/annexin V-negative; %) and apoptotic cells (PI-negative/annexin V-positive and PI-positive/annexin V-positive; %), as assessed by flow cytometry. Means ± SEM. *P<0.05 vs. control.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4496091&req=5

pone.0131946.g001: Geraniol action on viability of eEND2 cells.A, B: Cell viability (% of control) (A) and cytotoxicity (% of control– 100%) (B) of eEND2 cells, which were exposed for 24h to different doses (50–400μM; n = 4) of geraniol, Triton X-100 as cytotoxic control (TX) or vehicle (control; n = 4), as assessed by WST-1 assay (A) and LDH release assay (B). Means ± SEM. *P<0.05 vs. control. C-E: Representative graphs from flow cytometry analyses of PI- and annexin V-stained eEND2 cells, which were exposed for 24h to 200μM (D; n = 4) and 400μM (E; n = 4) geraniol or vehicle (control; C; n = 4). F-H: Viable cells (= PI-negative/annexin V-negative; %) (F), necrotic cells (= PI-positive/annexin V-negative; %) and apoptotic cells (PI-negative/annexin V-positive and PI-positive/annexin V-positive; %), as assessed by flow cytometry. Means ± SEM. *P<0.05 vs. control.
Mentions: In a first step we examined the effect of different doses of geraniol on the viability of eEND2 cells by means of a WST-1 assay. We found that geraniol doses of 50–400μM do not affect the viability of the cells (Fig 1A). Moreover, treatment of the cells in this dose range only showed a significant LDH release into the culture medium at a geraniol concentration of 400μM (Fig 1B). However, the extent of this LDH release (~10%) was rather low. These findings were confirmed by flow cytometric analyses of PI- and annexin V-stained eEND2 cells, which were exposed to 200 or 400μM geraniol (Fig 1C–1H). Once again, they exhibited a high fraction of viable cells (>90%) (Fig 1F). Besides, we found that geraniol dose-dependently induced necrotic and apoptotic cell death in a small fraction of cells (Fig 1G and 1H).

Bottom Line: In vitro, geraniol reduced the migratory activity of endothelial-like eEND2 cells.In addition, geraniol significantly reduced vascular sprout formation in a rat aortic ring assay.Immunohistochemical analyses confirmed a decreased number of Ki67-positive cells and CD31-positive microvessels with reduced VEGFR-2 expression within geraniol-treated tumors.

View Article: PubMed Central - PubMed

Affiliation: Institute for Clinical & Experimental Surgery, University of Saarland, Homburg/Saar, Germany.

ABSTRACT
Geraniol exerts several direct pharmacological effects on tumor cells and, thus, has been suggested as a promising anti-cancer compound. Because vascularization is a major precondition for tumor growth, we analyzed in this study the anti-angiogenic action of geraniol. In vitro, geraniol reduced the migratory activity of endothelial-like eEND2 cells. Western blot analyses further revealed that geraniol downregulates proliferating cell nuclear antigen (PCNA) and upregulates cleaved caspase-3 (Casp-3) expression in eEND2 cells. Moreover, geraniol blocked vascular endothelial growth factor (VEGF)/VEGFR-2 signal transduction, resulting in a suppression of downstream AKT and ERK signaling pathways. In addition, geraniol significantly reduced vascular sprout formation in a rat aortic ring assay. In vivo, geraniol inhibited the vascularization of CT26 tumors in dorsal skinfold chambers of BALB/c mice, which was associated with a smaller tumor size when compared to vehicle-treated controls. Immunohistochemical analyses confirmed a decreased number of Ki67-positive cells and CD31-positive microvessels with reduced VEGFR-2 expression within geraniol-treated tumors. Taken together, these findings indicate that geraniol targets multiple angiogenic mechanisms and, therefore, is an attractive candidate for the anti-angiogenic treatment of tumors.

No MeSH data available.


Related in: MedlinePlus