Institute of Chemical Biology and Fundamental Medicine SB RAS, Lavrentiev Ave., 8, 630090, Novosibirsk, Russia.
Protein J. 2010 Apr;29(3):174-80. doi: 10.1007/s10930-010-9237-5.
We recently isolated and characterized a human milk peptide, lactaptin, which induced apoptosis of cultured human MCF-7 cells. Lactaptin was identified as a proteolytic fragment of human kappa-casein. Here, we generated two recombinant analogs of the peptide, RL1 and RL2, containing truncated and complete amino acid sequences of lactaptin, respectively. Analogs were produced in E.coli, purified and assayed for biological activity on cultured human MCF-7 cells. RL1 was shown to induce only a small decrease in cell viability, whereas RL2 lowered the viability of MCF-7 cells by 60%. This reduction in MCF-7 cell viability was associated with apoptosis, which was indicated by phosphatidilserine externalization and caspase-7 activation. The viability of A549 and Hep-2 cells was also reduced by RL2, albeit to a lesser degree than seen with MCF-7 cells; this reduced viability was not accompanied by apoptosis. Non-malignant human mesenchymal stem cells (MSC) were completely resistant to RL2 action.
我们最近分离并鉴定了一种人乳肽，乳凝集素，它能诱导培养的人 MCF-7 细胞凋亡。乳凝集素被鉴定为人 κ-酪蛋白的酶解片段。在这里，我们生成了该肽的两个重组类似物 RL1 和 RL2，分别包含乳凝集素的截断和完整氨基酸序列。类似物在大肠杆菌中产生、纯化，并在培养的人 MCF-7 细胞上检测其生物活性。结果表明 RL1 仅能轻微降低细胞活力，而 RL2 则使 MCF-7 细胞活力降低 60%。MCF-7 细胞活力的降低与凋亡有关，这表现为磷脂酰丝氨酸外翻和半胱天冬酶-7 的激活。A549 和 Hep-2 细胞的活力也被 RL2 降低，尽管程度低于 MCF-7 细胞；这种降低的活力不伴有凋亡。非恶性人间充质干细胞（MSC）对 RL2 完全耐受。
