Contrast-enhanced Ultrasound in evaluating of angiogenesis and tumor staging of nasopharyngeal carcinoma in nude mice.

Shoujun Liang,Yanhao Chen,Shangyong Zhu,Yaoli Liu,Chengcheng Qiu,Yong Gao,Chryso Kanthou

doi:10.1371/journal.pone.0221638

Abstract

ObjectiveTo explore the use of Contrast-enhanced Ultrasound (CEUS) in evaluating angiogenesis in a xenograft nasopharyngeal carcinoma (NPC) model in nude mice and the evolution of CEUS parameters according to the growth of NPC.MethodsNude mice were divided into three groups according to experiments conducted at various times from tumor implantation (8 mice/group; group A: 4 weeks from implantation; group B:6 weeks from implantation; group C:8 weeks from implantation). CNE-2 cells were transplanted in 24 nude mice and CEUS evaluations of the tumors were performed at 4, 6 or 8 weeks from implantation. CEUS parametric perfusion images and pathological findings were recorded. R version 3.4.4 software was used to analyze the CEUS parameters and pathological findings.ResultsOne-way anova analysis indicated statistically significant differences among the three groups with the parameters of peak intensity (PI) (p<0.001), area wash in (AWI) (p<0.001), area wash out (AWO) (p<0.001) and tumor volumes (p<0.001).Pearson correlation coefficient analysis indicated that microvessel density (MVD) was correlated with tumor volume (r = 0.644, p = 0.001), PI (r = 0.904, p<0.0001), AWI (r = 0.547, p = 0.008) and AWO (r = 0.744, P<0.0001). Tumor volume was correlated with MVD (r = 0.644, p = 0.001), PI (r = 0.625, p = 0.002), AWI (r = 0.528, p = 0.012) and AWO (r = 0.784, p<0.001). The percentage of necrosis in histological sections was correlated with the percentage of CEUS unperfused area (r = 0.446,p = 0.038). Spearman rank correlation coefficient analysis indicated that vascular endothelial growth factor (VEGF) was correlated with PI (r = 0.462, P = 0.032). Welch t test indicated PI, AWI and AWO parameters were significantly lower than that of kidneys (p<0.001, p = 0.009, p = 0.005).ConclusionsThe CEUS parameters PI, AWI and AWO indirectly reflect the MVD and the tumor volume in our model of subcutaneous transplanted NPC in nude mice, providing precious information on angiogenesis and tumor growth. VEGF may play a role in promoting angiogenesis of NPC.

Highlights

Nasopharyngeal carcinoma (NPC) is a common type of cancer in south of China, especially in the Guangxi province[1]
One-way anova analysis indicated statistically significant differences among the three groups with the parameters of peak intensity (PI) (p
Spearman rank correlation coefficient analysis indicated that vascular endothelial growth factor (VEGF) was correlated with PI (r = 0.462, P = 0.032)

Summary

Introduction

Nasopharyngeal carcinoma (NPC) is a common type of cancer in south of China, especially in the Guangxi province[1]. It has an unbalanced geographical distribution, and nearly 80% of new NPC cases in 2008 were in Asia and only 5% were in Europe[2]. The majority of NPC patients are diagnosed only at the advanced stage and the five year survival rate is 50%-60%[3]. RT combined with anti-angiogenic treatment has been used in clinical trials and considered a promising model for NPC treatment[6, 7]

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Conclusion