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A novel peptide (GX1) homing to gastric cancer vasculature inhibits angiogenesis and cooperates with TNF alpha in anti-tumor therapy.

Chen B, Cao S, Zhang Y, Wang X, Liu J, Hui X, Wan Y, Du W, Wang L, Wu K, Fan D - BMC Cell Biol. (2009)

Bottom Line: In a tumor formation test, GX1-rmhTNFalpha more effectively inhibited tumor growth than rmhTNFalpha (tumor volume: 271 mm3 vs. 134 mm3, p < 0.05), with less systemic toxicity as measured by body weight (20.57 g vs. 19.30 g, p < 0.05).GX1 had both homing activity and the ability to inhibit vascular endothelial cell proliferation in vitro and neovascularization in vivo.Furthermore, when GX1 was conjugated to rmhTNFalpha, the fusion protein was selectively delivered to targeted tumor sites, significantly improving the anti-tumor activity of rmhTNFalpha and decreasing systemic toxicity.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases, the Fourth Military Medical University, Xi'an, Shaanxi, PR China. bzcheese@hotmail.com

ABSTRACT

Background: The discovery of the importance of angiogenesis in tumor growth has emphasized the need to find specific vascular targets for tumor-targeted therapies. Previously, using phage display technology, we identified the peptide GX1 as having the ability to target the gastric cancer vasculature. The present study investigated the bioactivities of GX1, as well as its potential ability to cooperate with recombinant mutant human tumor necrosis factor alpha (rmhTNFalpha), in gastric cancer therapy.

Results: Tetrazolium salt (MTT) assay showed that GX1 could inhibit cell proliferation of both human umbilical vein endothelial cells (HUVEC) (44%) and HUVEC with tumor endothelium characteristics, generated by culturing in tumor-conditioned medium (co-HUVEC) (62%). Flow-cytometry (FCM) and western blot assays showed that GX1 increased the rate of apoptosis from 11% to 31% (p < 0.01) by up-regulating caspase 3 expression level. A chorioallantoic membrane assay indicated that GX1 could suppress neovascularization in vivo, with the microvessel count decreasing from 21 to 11 (p < 0.05). When GX1 was fused to rmhTNFalpha, GX1-rmhTNFalpha selectively concentrated in the gastric cancer vasculature, as shown by enzyme-linked immunosorbent assay, immunofluorescence and emission-computed tomography. In vitro MTT and FCM assays showed that, compared to rmhTNFalpha alone, GX1-rmhTNFalpha was more effective at suppressing co-HUVEC proliferation (45% vs. 61%, p < 0.05) and inducing apoptosis (11% vs. 23%, p < 0.05). In a tumor formation test, GX1-rmhTNFalpha more effectively inhibited tumor growth than rmhTNFalpha (tumor volume: 271 mm3 vs. 134 mm3, p < 0.05), with less systemic toxicity as measured by body weight (20.57 g vs. 19.30 g, p < 0.05). These therapeutic effects may be mediated by selectively enhanced tumor vascular permeability, as indicated by Evan's blue assay.

Conclusion: GX1 had both homing activity and the ability to inhibit vascular endothelial cell proliferation in vitro and neovascularization in vivo. Furthermore, when GX1 was conjugated to rmhTNFalpha, the fusion protein was selectively delivered to targeted tumor sites, significantly improving the anti-tumor activity of rmhTNFalpha and decreasing systemic toxicity. These results demonstrate the potential of GX1 as a homing peptide in vascular targeted therapy for gastric cancer.

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GX1-rmhTNFα inhibits tumor growth with decreased systemic toxicity by enhancing tumor vascular permeability. (A) GX1-rmhTNFα significantly delayed tumor growth. (B) GX1-rmhTNFα led to less weight loss than rmhTNFα. (C) GX1-rmhTNFα induced a greater leakage of the dye in the tumor parenchyma than rmhTNFα. Bars, SD. * p < 0.05, **p < 0.01.
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Figure 6: GX1-rmhTNFα inhibits tumor growth with decreased systemic toxicity by enhancing tumor vascular permeability. (A) GX1-rmhTNFα significantly delayed tumor growth. (B) GX1-rmhTNFα led to less weight loss than rmhTNFα. (C) GX1-rmhTNFα induced a greater leakage of the dye in the tumor parenchyma than rmhTNFα. Bars, SD. * p < 0.05, **p < 0.01.

Mentions: Subsequently, using an in vivo tumor formation test, GX1-rmhTNFα was assayed for its effects on tumor growth. Nude mice bearing human gastric adenocarcinoma xenografts were injected intravenously on alternate days with GX1-rmhTNFα (0.5 mg/kg), rmhTNFα (0.5 mg/kg), GX1 (0.25 mg/kg to account for its lower molecular weight) or normal saline (NS). Mouse body weight, which is used as a major indicator of TNF toxicity [11,15], and tumor mass volumes were assessed over time. Tumor growth was significantly delayed by GX1-rmhTNFα treatment, and the average tumor volume of the GX1-rmhTNFα group was much smaller than that of the rmhTNFα group (134.33 mm3 vs. 271.50 mm3, p < 0.05) (Figure 6A). In addition, at the end of the test, mice treated with GX1-rmhTNFα had a higher average body weight than those treated with rmhTNFα (20.57 g vs. 19.30 g, p < 0.05) (Figure 6B), suggesting that the fusion protein had less systemic toxicity than rmhTNFα alone.


A novel peptide (GX1) homing to gastric cancer vasculature inhibits angiogenesis and cooperates with TNF alpha in anti-tumor therapy.

Chen B, Cao S, Zhang Y, Wang X, Liu J, Hui X, Wan Y, Du W, Wang L, Wu K, Fan D - BMC Cell Biol. (2009)

GX1-rmhTNFα inhibits tumor growth with decreased systemic toxicity by enhancing tumor vascular permeability. (A) GX1-rmhTNFα significantly delayed tumor growth. (B) GX1-rmhTNFα led to less weight loss than rmhTNFα. (C) GX1-rmhTNFα induced a greater leakage of the dye in the tumor parenchyma than rmhTNFα. Bars, SD. * p < 0.05, **p < 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2746182&req=5

Figure 6: GX1-rmhTNFα inhibits tumor growth with decreased systemic toxicity by enhancing tumor vascular permeability. (A) GX1-rmhTNFα significantly delayed tumor growth. (B) GX1-rmhTNFα led to less weight loss than rmhTNFα. (C) GX1-rmhTNFα induced a greater leakage of the dye in the tumor parenchyma than rmhTNFα. Bars, SD. * p < 0.05, **p < 0.01.
Mentions: Subsequently, using an in vivo tumor formation test, GX1-rmhTNFα was assayed for its effects on tumor growth. Nude mice bearing human gastric adenocarcinoma xenografts were injected intravenously on alternate days with GX1-rmhTNFα (0.5 mg/kg), rmhTNFα (0.5 mg/kg), GX1 (0.25 mg/kg to account for its lower molecular weight) or normal saline (NS). Mouse body weight, which is used as a major indicator of TNF toxicity [11,15], and tumor mass volumes were assessed over time. Tumor growth was significantly delayed by GX1-rmhTNFα treatment, and the average tumor volume of the GX1-rmhTNFα group was much smaller than that of the rmhTNFα group (134.33 mm3 vs. 271.50 mm3, p < 0.05) (Figure 6A). In addition, at the end of the test, mice treated with GX1-rmhTNFα had a higher average body weight than those treated with rmhTNFα (20.57 g vs. 19.30 g, p < 0.05) (Figure 6B), suggesting that the fusion protein had less systemic toxicity than rmhTNFα alone.

Bottom Line: In a tumor formation test, GX1-rmhTNFalpha more effectively inhibited tumor growth than rmhTNFalpha (tumor volume: 271 mm3 vs. 134 mm3, p < 0.05), with less systemic toxicity as measured by body weight (20.57 g vs. 19.30 g, p < 0.05).GX1 had both homing activity and the ability to inhibit vascular endothelial cell proliferation in vitro and neovascularization in vivo.Furthermore, when GX1 was conjugated to rmhTNFalpha, the fusion protein was selectively delivered to targeted tumor sites, significantly improving the anti-tumor activity of rmhTNFalpha and decreasing systemic toxicity.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases, the Fourth Military Medical University, Xi'an, Shaanxi, PR China. bzcheese@hotmail.com

ABSTRACT

Background: The discovery of the importance of angiogenesis in tumor growth has emphasized the need to find specific vascular targets for tumor-targeted therapies. Previously, using phage display technology, we identified the peptide GX1 as having the ability to target the gastric cancer vasculature. The present study investigated the bioactivities of GX1, as well as its potential ability to cooperate with recombinant mutant human tumor necrosis factor alpha (rmhTNFalpha), in gastric cancer therapy.

Results: Tetrazolium salt (MTT) assay showed that GX1 could inhibit cell proliferation of both human umbilical vein endothelial cells (HUVEC) (44%) and HUVEC with tumor endothelium characteristics, generated by culturing in tumor-conditioned medium (co-HUVEC) (62%). Flow-cytometry (FCM) and western blot assays showed that GX1 increased the rate of apoptosis from 11% to 31% (p < 0.01) by up-regulating caspase 3 expression level. A chorioallantoic membrane assay indicated that GX1 could suppress neovascularization in vivo, with the microvessel count decreasing from 21 to 11 (p < 0.05). When GX1 was fused to rmhTNFalpha, GX1-rmhTNFalpha selectively concentrated in the gastric cancer vasculature, as shown by enzyme-linked immunosorbent assay, immunofluorescence and emission-computed tomography. In vitro MTT and FCM assays showed that, compared to rmhTNFalpha alone, GX1-rmhTNFalpha was more effective at suppressing co-HUVEC proliferation (45% vs. 61%, p < 0.05) and inducing apoptosis (11% vs. 23%, p < 0.05). In a tumor formation test, GX1-rmhTNFalpha more effectively inhibited tumor growth than rmhTNFalpha (tumor volume: 271 mm3 vs. 134 mm3, p < 0.05), with less systemic toxicity as measured by body weight (20.57 g vs. 19.30 g, p < 0.05). These therapeutic effects may be mediated by selectively enhanced tumor vascular permeability, as indicated by Evan's blue assay.

Conclusion: GX1 had both homing activity and the ability to inhibit vascular endothelial cell proliferation in vitro and neovascularization in vivo. Furthermore, when GX1 was conjugated to rmhTNFalpha, the fusion protein was selectively delivered to targeted tumor sites, significantly improving the anti-tumor activity of rmhTNFalpha and decreasing systemic toxicity. These results demonstrate the potential of GX1 as a homing peptide in vascular targeted therapy for gastric cancer.

Show MeSH
Related in: MedlinePlus