Department of Medical Oncology, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, The Netherlands.
Br J Cancer. 2011 Mar 29;104(7):1185-92. doi: 10.1038/bjc.2011.74. Epub 2011 Mar 8.
Thymidine phosphorylase (TP) is often overexpressed in tumours and has a role in tumour aggressiveness and angiogenesis. Here, we determined whether TP increased tumour invasion and whether TP-expressing cancer cells stimulated angiogenesis.
Angiogenesis was studied by exposing endothelial cells (HUVECs) to conditioned medium (CM) derived from cancer cells with high (Colo320TP1=CT-CM, RT112/TP=RT-CM) and no TP expression after which migration (wound-healing-assay) and invasion (transwell-assay) were determined. The involvement of several angiogenic factors were examined by RT-PCR, ELISA and blocking antibodies.
Tumour invasion was not dependent on intrinsic TP expression. The CT-CM and RT-CM stimulated HUVEC-migration and invasion by about 15 and 40%, respectively. Inhibition by 10 μM TPI and 100 μM L-dR, blocked migration and reduced the invasion by 50-70%. Thymidine phosphorylase activity in HUVECs was increased by CT-CM. Reverse transcription-polymerase chain reaction revealed a higher mRNA expression of bFGF (Colo320TP1), IL-8 (RT112/TP) and TNF-α, but not VEGF. Blocking antibodies targeting these factors decreased the migration and invasion that was induced by the CT-CM and RT-CM, except for IL-8 in CT-CM and bFGF in RT-CM.
In our cell line panels, TP did not increase the tumour invasion, but stimulated the migration and invasion of HUVECs by two different mechanisms. Hence, TP targeting seems to provide a potential additional strategy in the field of anti-angiogenic therapy.
胸苷磷酸化酶（TP）在肿瘤中常过度表达，在肿瘤侵袭性和血管生成中起作用。在这里，我们确定 TP 是否会增加肿瘤侵袭性，以及表达 TP 的癌细胞是否会刺激血管生成。
通过将内皮细胞（HUVEC）暴露于高表达 TP（Colo320TP1=CT-CM，RT112/TP=RT-CM）和无 TP 表达的癌细胞来源的条件培养基（CM）中，研究血管生成，然后测定迁移（划痕愈合试验）和侵袭（Transwell 试验）。通过 RT-PCR、ELISA 和阻断抗体检测几种血管生成因子的参与情况。
肿瘤侵袭性不依赖于内在的 TP 表达。CT-CM 和 RT-CM 分别刺激 HUVEC 迁移和侵袭约 15%和 40%。用 10μM TPI 和 100μM L-dR 抑制，可阻断迁移并将侵袭减少 50-70%。CT-CM 可增加 HUVEC 中的胸苷磷酸化酶活性。逆转录聚合酶链反应显示 bFGF（Colo320TP1）、IL-8（RT112/TP）和 TNF-α的 mRNA 表达较高，但 VEGF 除外。针对这些因子的阻断抗体可降低 CT-CM 和 RT-CM 诱导的迁移和侵袭，但 CT-CM 中的 IL-8 和 RT-CM 中的 bFGF 除外。
在我们的细胞系面板中，TP 并未增加肿瘤侵袭性，但通过两种不同的机制刺激 HUVEC 的迁移和侵袭。因此，TP 靶向似乎为抗血管生成治疗领域提供了一种潜在的额外策略。
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