State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China ; Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong SAR, China.
PLoS One. 2013 Oct 15;8(10):e77516. doi: 10.1371/journal.pone.0077516. eCollection 2013.
Insulin-like growth factor binding protein-3 (IGFBP-3) is a multifunctional molecule which is closely related to cell growth, apoptosis, angiogenesis, metabolism and senescence. It combines with insulin-like growth factor-I (IGF-I) to form a complex (IGF-I/IGFBP-3) that can treat growth hormone insensitivity syndrome (GHIS) and reduce insulin requirement in patients with diabetes. IGFBP-3 alone has been shown to have anti-proliferation effect on numerous cancer cells.
METHODOLOGY/PRINCIPAL FINDINGS: We reported here an expression method to produce functional recombinant human IGFBP-3 (rhIGFBP-3) in transgenic rice grains. Protein sorting sequences, signal peptide and endoplasmic reticulum retention tetrapeptide (KDEL) were included in constructs for enhancing rhIGFBP-3 expression. Western blot analysis showed that only the constructs with signal peptide were successfully expressed in transgenic rice grains. Both rhIGFBP-3 proteins, with or without KDEL sorting sequence inhibited the growth of MCF-7 human breast cancer cells (65.76 ± 1.72% vs 45.00 ± 0.86%, p < 0.05; 50.84 ± 1.97% vs 45.00 ± 0.86%, p < 0.01 respectively) and HT-29 colon cancer cells (65.14 ± 3.84% vs 18.01 ± 13.81%, p < 0.05 and 54.7 ± 9.44% vs 18.01 ± 13.81%, p < 0.05 respectively) when compared with wild type rice.
CONCLUSION/SIGNIFICANCE: These findings demonstrated the feasibility of producing biological active rhIGFBP-3 in rice using a transgenic approach, which will definitely encourage more research on the therapeutic use of hIGFBP-3 in future.
胰岛素样生长因子结合蛋白-3（IGFBP-3）是一种多功能分子，与细胞生长、凋亡、血管生成、代谢和衰老密切相关。它与胰岛素样生长因子-I（IGF-I）结合形成复合物（IGF-I/IGFBP-3），可治疗生长激素不敏感综合征（GHIS）并降低糖尿病患者的胰岛素需求。IGFBP-3 本身已被证明对许多癌细胞具有抗增殖作用。
方法/主要发现：我们在这里报告了一种在转基因水稻粒中产生功能性重组人 IGFBP-3（rhIGFBP-3）的表达方法。包含蛋白分选序列、信号肽和内质网保留四肽（KDEL）的构建体用于增强 rhIGFBP-3 的表达。Western blot 分析表明，只有带有信号肽的构建体才能在转基因水稻粒中成功表达。带有或不带有 KDEL 分选序列的 rhIGFBP-3 蛋白均能抑制 MCF-7 人乳腺癌细胞（65.76 ± 1.72%比 45.00 ± 0.86%，p < 0.05；50.84 ± 1.97%比 45.00 ± 0.86%，p < 0.01）和 HT-29 结肠癌细胞（65.14 ± 3.84%比 18.01 ± 13.81%，p < 0.05 和 54.7 ± 9.44%比 18.01 ± 13.81%，p < 0.05）的生长。
结论/意义：这些发现证明了使用转基因方法在水稻中生产生物活性 rhIGFBP-3 的可行性，这必将鼓励未来更多地研究 hIGFBP-3 的治疗用途。
