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，也称为CXCL 14。我们以前报道过BRAK在头颈部鳞状细胞癌细胞（HNSCC）中具有有效的抗肿瘤活性，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通过直接结合这些细胞因子来抑制血管生成细胞因子如IL-8的作用。在第一年，我们构建了FLAG-BRAK和FLAG-MOCK载体，并将这些载体转染到HSC-2细胞中，获得了稳定表达这些载体的HSC-2/FRAG-BRAK和HSC-2/FRAG-MOCK细胞。接下来，为了研究BRAKE与这些细胞因子的结合能力，我们将重组蛋白IL-8或VEGF添加到HSC-2/FRAG-BRAKE细胞或HSC-2/FRAG-MOCK细胞的培养基中，并收集培养基。在培养基的免疫纯化之后，我们研究了BRAK与这些细胞因子的结合，并且发现分泌到培养基中的BRAK与IL-8结合。我们的研究结果提高了利用BRAKE衍生的IL-8结合肽开发血管生成抑制肽的可能性。

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.