PEG修饰有效提高热休克蛋白gp96抑制性多肽抗乳腺癌的功能

PEGylation effectively improves anti-breast cancer efficiency of heat shock protein gp96 inhibitory polypeptide

摘要:

乳腺癌是女性恶性肿瘤中发病率最高的肿瘤，严重威胁女性生命健康。其中三阴性乳腺癌因其特殊的生理学特点，成为乳腺癌中预后最差的亚型，因此急需寻找新的靶点进行治疗来提高患者预后及生存率。多项研究表明，热休克蛋白gp96在多种癌细胞的膜表面过表达，且胞膜gp96与乳腺癌的恶性程度与不良预后密切相关，因此其可能是乳腺癌治疗的新靶点。前期研究根据gp96的结构，开发一种靶向胞膜gp96 ATP结合区的α螺旋肽p37。虽然p37多肽作用位点专一，但其在体内容易被降解，因此本研究将多肽的N端或C端分别偶联PEG₂₀₀₀或PEG₅₀₀₀，得到4个具有抑瘤功能的PEG多肽：mPEG₂₀₀₀CY、mPEG₅₀₀₀CY、mPEG₂₀₀₀LC和mPEG₅₀₀₀LC。它们可以抑制乳腺癌细胞SK-BR-3的增殖和侵袭，其中抑制效果最明显的是mPEG₂₀₀₀CY。经测定，mPEG₂₀₀₀CY在体内的半衰期较多肽p37明显延长，且有效抑制三阴性乳腺癌MDA-MB-231小鼠移植瘤的生长。这为研发新型抗乳腺癌尤其是三阴性乳腺癌的靶向药物提供了依据。

关键词:肿瘤;三阴性乳腺癌;胞膜gp96;抑制性多肽;PEG修饰多肽

Abstract:

Breast cancer is the most common tumor in female, which seriously threatens the health of women. Triple-negative breast cancer is a subtype with the worst prognosis because of its special physiological characteristics and lack of targeted drugs. Therefore, it is urgent to develop new targeted treatments to improve the prognosis and survival rate of the patients. Previous studies have shown that heat shock protein gp96 is expressed on the membrane of a variety of cancer cells but not on the normal cells. Cell membrane gp96 levels are closely related to the poor prognosis of breast cancer, which may serve as a new target for breast cancer treatment. Based on the structure of gp96, we designed an α-helical peptide p37 that specifically targeting the ATP binding region of gp96. To improve the stability and decrease the degradation of the peptide, the N-terminus or C-terminus of p37 was coupled to PEG₂₀₀₀ or PEG₅₀₀₀ respectively, and four PEGylated polypeptides were obtained:mPEG₂₀₀₀CY, mPEG₅₀₀₀CY, mPEG₂₀₀₀LC, and mPEG₅₀₀₀LC. The PEGylated polypeptides inhibited the proliferation and invasion of breast cancer cell SK-BR-3, among which mPEG₂₀₀₀CY showed the most significant inhibitory effect. The half-life of mPEG₂₀₀₀CY in vivo was significantly longer than p37, and it effectively inhibited the growth of xenografted tumors of triple-negative breast cancer MDA-MB-231. The results provide a basis for the development of new targeted drugs against breast cancer, especially the triple-negative breast cancer.

Key words:cancer;triple-negative breast cancer;cell membrane gp96;inhibitory peptide;PEGylation of peptide