Limits...
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

Histological and immunohistochemical analysis of tumors.A, E: HE-stained cross sections of CT26 tumors (borders marked by dotted line) at day 14 after transplantation of tumor spheroids onto the striated muscle tissue (arrows) within the dorsal skinfold chamber of a vehicle-treated control mouse (A) and a geraniol-treated animal (E). Scale bars: 300μm. B, C, D, F, G, H: Immunohistochemical detection of CD31 (B, F, red), Ki67 (C, G, red) and Casp-3 (D, H, red) in CT26 tumors at day 14 after transplantation of tumor spheroids into the dorsal skinfold chamber of a vehicle-treated control mouse (B, C, D) and a geraniol-treated animal (F, G, H). Sections were stained with Hoechst 33342 to identify cell nuclei (blue). Scale bars: 40μm. I-K: Microvessel density (mm-2) (I), Ki67-positive cells (%) (J) and Casp-3-positive cells (%) (K) in CT26 tumors in dorsal skinfold chambers of vehicle-treated (white bars; n = 8) and geraniol-treated BALB/c mice (black bars; n = 8), as assessed by quantitative immunohistochemical analysis. Means ± SEM. *P<0.05 vs. control.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4496091&req=5

pone.0131946.g008: Histological and immunohistochemical analysis of tumors.A, E: HE-stained cross sections of CT26 tumors (borders marked by dotted line) at day 14 after transplantation of tumor spheroids onto the striated muscle tissue (arrows) within the dorsal skinfold chamber of a vehicle-treated control mouse (A) and a geraniol-treated animal (E). Scale bars: 300μm. B, C, D, F, G, H: Immunohistochemical detection of CD31 (B, F, red), Ki67 (C, G, red) and Casp-3 (D, H, red) in CT26 tumors at day 14 after transplantation of tumor spheroids into the dorsal skinfold chamber of a vehicle-treated control mouse (B, C, D) and a geraniol-treated animal (F, G, H). Sections were stained with Hoechst 33342 to identify cell nuclei (blue). Scale bars: 40μm. I-K: Microvessel density (mm-2) (I), Ki67-positive cells (%) (J) and Casp-3-positive cells (%) (K) in CT26 tumors in dorsal skinfold chambers of vehicle-treated (white bars; n = 8) and geraniol-treated BALB/c mice (black bars; n = 8), as assessed by quantitative immunohistochemical analysis. Means ± SEM. *P<0.05 vs. control.

Mentions: At day 14 after spheroid transplantation further histological and immunohistochemical analyses of tissue samples from the dorsal skinfold chamber preparations were performed. It was found that geraniol-treated tumor spheroids exhibited a markedly reduced size on HE-stained cross sections when compared to controls (Fig 8A and 8E). Moreover, the density of CD31-positive microvessels (Fig 8B, 8F and 8I) and the number of Ki67-positive proliferating cells (Fig 8C, 8G and 8J) was significantly lower in geraniol-treated spheroids. In both groups, we detected a very low fraction of Casp-3-positive apoptotic cells, which, however, did not differ between geraniol-treated and vehicle-treated control spheroids (Fig 8D, 8H and 8K). More detailed analyses of the tumor microvasculature revealed that geraniol-treated CD31-positive endothelial cells exhibited a reduced expression of VEGFR-2 when compared to vehicle-treated controls (Fig 9A–9F).


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)

Histological and immunohistochemical analysis of tumors.A, E: HE-stained cross sections of CT26 tumors (borders marked by dotted line) at day 14 after transplantation of tumor spheroids onto the striated muscle tissue (arrows) within the dorsal skinfold chamber of a vehicle-treated control mouse (A) and a geraniol-treated animal (E). Scale bars: 300μm. B, C, D, F, G, H: Immunohistochemical detection of CD31 (B, F, red), Ki67 (C, G, red) and Casp-3 (D, H, red) in CT26 tumors at day 14 after transplantation of tumor spheroids into the dorsal skinfold chamber of a vehicle-treated control mouse (B, C, D) and a geraniol-treated animal (F, G, H). Sections were stained with Hoechst 33342 to identify cell nuclei (blue). Scale bars: 40μm. I-K: Microvessel density (mm-2) (I), Ki67-positive cells (%) (J) and Casp-3-positive cells (%) (K) in CT26 tumors in dorsal skinfold chambers of vehicle-treated (white bars; n = 8) and geraniol-treated BALB/c mice (black bars; n = 8), as assessed by quantitative immunohistochemical analysis. Means ± SEM. *P<0.05 vs. control.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0131946.g008: Histological and immunohistochemical analysis of tumors.A, E: HE-stained cross sections of CT26 tumors (borders marked by dotted line) at day 14 after transplantation of tumor spheroids onto the striated muscle tissue (arrows) within the dorsal skinfold chamber of a vehicle-treated control mouse (A) and a geraniol-treated animal (E). Scale bars: 300μm. B, C, D, F, G, H: Immunohistochemical detection of CD31 (B, F, red), Ki67 (C, G, red) and Casp-3 (D, H, red) in CT26 tumors at day 14 after transplantation of tumor spheroids into the dorsal skinfold chamber of a vehicle-treated control mouse (B, C, D) and a geraniol-treated animal (F, G, H). Sections were stained with Hoechst 33342 to identify cell nuclei (blue). Scale bars: 40μm. I-K: Microvessel density (mm-2) (I), Ki67-positive cells (%) (J) and Casp-3-positive cells (%) (K) in CT26 tumors in dorsal skinfold chambers of vehicle-treated (white bars; n = 8) and geraniol-treated BALB/c mice (black bars; n = 8), as assessed by quantitative immunohistochemical analysis. Means ± SEM. *P<0.05 vs. control.
Mentions: At day 14 after spheroid transplantation further histological and immunohistochemical analyses of tissue samples from the dorsal skinfold chamber preparations were performed. It was found that geraniol-treated tumor spheroids exhibited a markedly reduced size on HE-stained cross sections when compared to controls (Fig 8A and 8E). Moreover, the density of CD31-positive microvessels (Fig 8B, 8F and 8I) and the number of Ki67-positive proliferating cells (Fig 8C, 8G and 8J) was significantly lower in geraniol-treated spheroids. In both groups, we detected a very low fraction of Casp-3-positive apoptotic cells, which, however, did not differ between geraniol-treated and vehicle-treated control spheroids (Fig 8D, 8H and 8K). More detailed analyses of the tumor microvasculature revealed that geraniol-treated CD31-positive endothelial cells exhibited a reduced expression of VEGFR-2 when compared to vehicle-treated controls (Fig 9A–9F).

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