Development of CXCL14/BRAK-derived anti-tumour peptide in head and neck squamous cell carcinoma.

Brak是一种非ELR基序的CXC趋化因子，也被称为CXCL14。我们以前报道过Brak在头颈部鳞状细胞癌细胞(HNSCC)中具有很强的抗肿瘤活性，但其作用机制和受体尚不清楚。为了阐明Brak抑制肿瘤的机制，我们假设Brak通过直接与IL-8等血管生成细胞因子结合来抑制这些细胞因子的作用。第一年，我们构建了FLAG-Brak和FLAG-MOCK载体，并将其导入HSC-2细胞，获得了稳定表达这些载体的细胞，命名为HSC-2/FRAG-Brak和HSC-2/FRAG-MOCK细胞。第二年，为了研究Brak与这些细胞因子的结合能力，我们在HSC-2/FRAG-Brak细胞或HSC-2/FRAG-MOCK细胞的培养液中加入重组蛋白IL-8或VEGF，并收集培养液。免疫纯化后，我们研究了Brak与这些细胞因子的结合，发现Brak分泌到与IL-8结合的培养液中。我们的结果为利用Brak来源的IL-8结合多肽开发血管生成抑制多肽提供了可能性。

BRAK, one of a non-ELR motif CXC chemokine, is also known as CXCL14. We previously reported that BRAK has a potent anti-tumor activity in head and neck squamous cell carcinoma cells (HNSCC), but the mechanism of action nor receptor for it is not known. In order to clarify the mechanism of tumor suppression by the BRAK we hypothesized that BRAK inhibits action of angiogenic cytokines such as IL-8 by directly binding to these cytokines. In the first year, we constructed FLAG-BRAK and FLAG-MOCK vectors and transfected these vectors into HSC-2 cells and obtained stably expressing these constructs, and named HSC-2/FRAG-BRAK, and HSC-2/FRAG-MOCK cells. Next year, in order to investigate binding capability of BRAK with these cytokines, we added recombinant proteins IL-8 or VEGF to the culture medium of HSC-2/FRAG-BRAK cells or HSC-2/FRAG-MOCK cells, and collected the culture medium. Following immunopurification of the culture medium, we investigated binding of BRAK with these cytokines and found that BRAK secreted into the culture medium bound with IL-8. Our results raise the possibility to develop angiogenesis inhibitory peptides by use of IL-8-binding peptides derived BRAK.