BRAF V600E maintains proliferation, transformation, and tumorigenicity of BRAF-mutant papillary thyroid cancer cells
BRAF V600E maintains proliferation, transformation, and tumorigenicity of BRAF-mutant papillary thyroid cancer cells
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DOI：
10.1210/jc.2006-1613
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发表时间：
2007-06-01
影响因子：
5.8
通讯作者：
Xing, Mingzhao
中科院分区：
文献类型：
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作者：
Liu, Dingxie;Liu, Zhi;Xing, Mingzhao
背景：虽然BRAF V600E突变体可以启动甲状腺乳头状癌（PTC）的形成，但目前尚不清楚是否需要它来维持BRAF突变携带的PTC的细胞增殖、转化和肿瘤生长。目的：研究BRAF V600E是否为BRAF突变的PTC细胞增殖、转化和致瘤性所必需。设计：我们使用BRAF小干扰RNA （siRNA）稳定转染几种BRAF突变的PTC细胞系，分离出稳定抑制BRAF的克隆，并评估它们在裸鼠体内增殖、转化和生长异种移植肿瘤的能力。结果：PTC细胞的增殖和转化在特定的BRAF siRNA克隆中受到抑制，而在对照的打乱siRNA克隆中没有受到抑制。具体来说，利用稳定的BRAF敲除，我们能够在长期培养后持续抑制PTC细胞的增殖和转化，或在软琼脂中不依赖锚定的集落形成。此外，我们还证明，与对照克隆相比，来自特定BRAF siRNA细胞克隆的裸鼠体内致瘤性和肿瘤生长受到抑制。结论：BRAF V600E不仅如前所述是PTC的启动物，而且是携带BRAF突变的PTC细胞增殖、转化和致瘤性的维持者，并且这些细胞衍生的肿瘤的生长继续依赖BRAF V600E。这些结果进一步支持了针对BRAF的潜在有效治疗BRAF突变的PTC。
Context: Although the BRAF V600E mutant can initiate the formation of papillary thyroid cancer (PTC), it is unclear whether it is required to maintain cell proliferation, transformation, and tumor growth of BRAF mutation-harboring PTC.Objective: The aim of the study was to investigate whether BRAF V600E is required for the proliferation, transformation, and tumorigenicity of BRAF mutation-harboring PTC cells.Design: We addressed this issue using BRAF small interference RNA (siRNA) to transfect stably several BRAF mutation-harboring PTC cell lines, isolated clones with stable suppression of BRAF, and assessed their ability to proliferate, transform, and grow xenograft tumors in nude mice.Results: PTC cell proliferation and transformation were suppressed in specific BRAF siRNA clones, but not in control scrambled siRNA clones. Specifically, taking the advantage of stable BRAF knockdown, we were able to show continued suppression of PTC cell proliferation and transformation, or anchorage-independent colony formation in soft agar, after long-term culture. Moreover, we also demonstrated that in vivo tumorigenicity and growth of tumors from the specific BRAF siRNA cell clones in nude mice were suppressed compared with control clones.Conclusions: BRAF V600E is not only an initiator of PTC as demonstrated previously but is also a maintainer of proliferation, transformation, and tumorigenicity of PTC cells harboring BRAF mutation, and growth of tumors derived from such cells continues to depend on BRAF V600E. These results provide further support for potentially effective therapy targeted at BRAF for BRAF mutation-harboring PTC.