一种溶酶体靶向的原位自组装短肽设计及抗肿瘤活性研究

肿瘤已成为威胁人类生命的一大杀手,目前主要采用手术和放、化疗等手段进行治疗,但由于放、化疗的细胞选择性差、毒副作用明显且易引起肿瘤细胞产生耐受(/药)性,不利于肿瘤的持续治疗,因此亟待研发具有定向定位优势、毒副作用低的新型靶向药物.原位自组装多肽能识别肿瘤部位的特异性高表达物质,在肿瘤部位靶向性聚集形成稳定的纳米结构,实现精准和高效治疗,有望成为一种新型的抗肿瘤药物.本研究基于多肽原位自组装的设计理念,利用溶酶体内组织蛋白酶L的催化活性,设计了靶向溶酶体且能够原位自组装的多肽分子Fmoc-FFRIKFERQ-OH,研究了该分子的自组装特性及抗肿瘤活性.结果显示,在体外酸性条件下,组织蛋白酶L能精准切割Fmoc-FFRIKFERQ-OH分子,其酶切产物FmocFFR-OH自组装形成长纳米纤维结构,对肿瘤细胞A375和SH-SY5Y均具有较好的杀伤作用.该分子通过靶向溶酶体杀伤肿瘤细胞且对正常细胞的毒性较低,有望成为一种新型的抗肿瘤药物.

Design of a Lysosome Targeting in situ Self-assembly Peptide and Its Antitumor Activity

Tumor has greatly threatened to human life. Now the main means of tumor treatment are surgery and(/or) chemoradiotherapy. However, the chemoradiotherapy is usually not suitable to sustained treatment of tumors due to its poor cell selectivity, side effects and inducing tumor cells resistance. Therefore, it is urgent to develop new drugs with low toxicity and high activity at the tumor sites. In situ self-assembly peptides which can target the tumors and self-assemble into specific nanostructures induced by the specific and highly expressed substances at the tumor tissues are expected to be a new kind of anti-tumor drugs. In this study, we designed a peptide denoted as Fmoc-FFRIKFERQ-OH based on the concept of in situ self-assembly of peptides. This peptide can target lysosomes and self-assemble in situ after being degraded by cathepsin L in lysosomes. The self-assembly properties of Fmoc-FFRIKFERQ-OH and its enzymolysis products degraded by cathepsin L were oberved by AFM and MALDI-TOF-MS. The anti-tumor activity of this peptide was measured by using the MTT and flow cytometry assay. The results demonstrated that cathepsin L could precisely hydrolyze the Fmoc-FFRIKFERQ-OH molecule under acidic conditions in vitro, and its enzymolysis product Fmoc-FFR-OH self-assembled into long nanofibers, which had high antitumor activity against both A375 and SH-SY5Y cells. The relative survival rate was only 36.08% and 25.56% for A375 and SH-SY5Y, respectively. Comparatively, Fmoc-FFRIKFERQ-OH had lower toxic and side effects on normal cells L929. The self-assembled long fibers formed by Fmoc-FFR-OH can disrupt the membrane of lysosome, which can induce cell apoptosis and(/or) death. Thus, the designed Fmoc-FFRIKFERQ-OH is expected to be a new anti-tumor drug due to its high antitumor activity and low toxicity against to normal cells.