To develop fusion protein of a GnRH Fc fragment and the integrin targeting AP25 antitumor peptide for GnRH receptor-expressing cancer therapy. The LMRAP fusion protein was constructed. A transwell invasion assay was performed. The gene mRNA and protein levels of GnRHR-I, α5β1, and αvβ3 in different cancer cell lines were assessed. Cell proliferation was measured using a cell counting kit-8. An antagonist assay was performed on GnRH receptors. Anti-tumor activity was evaluated with a mouse xenograft tumor model. Immunohistochemistry (IHC) was applied to detect CD31 and CD34 expressions. Pharmacokinetic characteristics were determined with an indirect competition ELISA. The developed bifunctional fusion protein LMRAP not only inhibited HUVEC invasion, but also inhibited proliferation of GnRHR-I, α5β1, and αvβ3 high expression cancer cells. The IC50 for LMRAP in the GnRH receptor was 6.235 × 10-4 mol/L. LMRAP significantly inhibited human prostate cancer cell line 22RV1 proliferation in vivo and in vitro. LMRAP significantly inhibited CD31 and CD34 expressions. The elimination half-life of the fusion protein LMRAP was 33 h in rats. The fusion protein made of a GnRH Fc fragment and the integrin targeting AP25 peptide retained the bifunctional biological activity of GnRHR blocking, angiogenesis inhibition, prolonged half-life and good tolerance.

中文翻译：

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优化的双靶LMRAP功能和结构设计，双靶LMRAP是一种具有25个氨基酸的抗肿瘤肽和GnRH Fc片段的双功能融合蛋白。

开发GnRH Fc片段和整合素靶向AP25抗肿瘤肽的融合蛋白，用于表达GnRH受体的癌症治疗。构建了LMRAP融合蛋白。进行transwell侵袭测定。评估了不同癌细胞系中GnRHR-1，α5β1和αvβ3的基因mRNA和蛋白质水平。使用细胞计数试剂盒8测量细胞增殖。在GnRH受体上进行了拮抗剂测定。用小鼠异种移植肿瘤模型评价抗肿瘤活性。免疫组织化学（IHC）被用于检测CD31和CD34的表达。用间接竞争ELISA确定药代动力学特征。研发的双功能融合蛋白LMRAP不仅抑制HUVEC侵袭，而且还抑制GnRHR-1，α5β1和αvβ3高表达癌细胞的增殖。GnRH受体中LMRAP的IC50为6.235×10-4 mol / L。LMRAP在体内和体外显着抑制人前列腺癌细胞系22RV1的增殖。LMRAP显着抑制CD31和CD34的表达。在大鼠中，融合蛋白LMRAP的消除半衰期为33小时。由GnRH Fc片段和整合素靶向AP25肽组成的融合蛋白保留了GnRHR阻断，血管生成抑制，半衰期延长和良好耐受性的双功能生物学活性。