Aminopeptidase N(APN/CD13), a Zn2+-dependent ectopeptidase localized on the cell surface, is widely considered to influence the invasion of tumor cells. We found that boroleucine and dino-leucine borate exhibited a strong inhibitory effect on the enzyme activity of aminopeptidase N. The tested assay indicated that both compounds had an anti-proliferative effect on triple-negative breast cancer cells. Wound healing assay, migration test and matrigel-coated transwell assay showed that both boroleucine and dino-leucine borate inhibited the migration and invasion of breast cancer cells. Immunoblot analysis showed that both compounds down-regulated the expression of matrix metalloproteinase-2/9. In the capillary tube formation assay of human umbilical vein endothelial cells (HUVECs), dino-leucine borate showed better antiangiogenic activity than ubenimex even at a low concentration (10 μM). Moreover, compared with ubenimex, the anti-metastatic activity of dino-leucine borate in vivo was similar to or even better than that of ubenimex in the H22 pulmonary metastasis mouse model. In this paper, we found the novel APN inhibitors to markedly suppress the enzyme activity of APN and inhibit the migration and invasion of tumor cells in vitro and in vivo.

Multidrug resistance (MDR) of hepatocellular carcinoma (HCC) is a serious problem that directly hinders the effect of chemotherapeutics. In this study, we mainly explore the molecular mechanism of ROS-induced CD13 expression using hepatocarcinoma cells as the research object. We show that the drug of fluorouracil (5FU), epirubicin (EPI) and gemcitabine (GEM) can induce ROS generation, activate Ets2 and promote CD13 expression. Meanwhile, CD13 can activate NRF1 and up-regulate ROS scavenging genes transcription, such as SOD1, GPX1, GPX2 and GPX3, leading to down-regulation of intracellular ROS level and reducing the sensitivity of cells to chemotherapy agent. We also detected the anti-tumor effect of the combination therapy, CD13 inhibitor ubenimex and a variety of conventional anti-cancer drugs, such as 5FU, EPI, GEM, pemetrexed (Pem) and paclitaxel (PTX) were employed in combination. Ubenimex enhances the sensitivity of different chemotherapeutic agents and cooperates with chemotherapeutic agents to suppress tumor growth in vitro and in vivo . In general, overexpression of CD13 can lead to chemotherapy resistance, and CD13 inhibitor can reverse this effect. Combination of chemotherapy agent and ubenimex will become a potential treatment strategy for liver cancer resistance.

目的 开发一种能准确、特异地评价目标化合物对人氨肽酶N的抑酶活性检测试剂盒.方法 验证试剂盒准确度、精密度、稳定性等性能指标,同时通过与同类的传统试剂盒进行米氏常数的评价确认该试剂盒的灵敏度.结果 精密度验证,试剂盒的CV=4.29％符合CV<15％的要求;准确度验证中,标准化残差δ*=1.747落在(-2,2)区间以内,在95％置信度内是正常实验点,数据准确可靠;酶源稳定性良好;线性范围宽,96孔板中氨肽酶N在加入量120μL时还能呈现良好的线性关系;该试剂盒米氏常数低于传统试剂盒,说明灵敏度高.结论 所开发的试剂盒主要的性能指标表现良好,能准确测定化合物对人源氨肽酶N的抑酶活性,其检测成本和可靠性优于现有上市产品,具有推广应用及开发价值.

Breast cancer is a common type of cancer in females. Our previous studies indicated that leucine aminopeptidase 3 (LAP3) promotes migration and invasion of breast cancer cells. Vimentin is a mesenchymal marker, and its upregulation represents the promotion of epithelial–mesenchymal transition. In this study, we found that LAP3 and vimentin were highly expressed in breast cancer tissues, and the overexpression of LAP3 in breast cancer cells promoted the expression of vimentin. Western blot analysis indicated that the overexpression of LAP3 upregulated the phosphorylation of Erk1/2. MEK inhibitor PD98059 downregulated the expression of vimentin, matrix metalloproteinase-2/9 (MMP-2/9), and fascin through the inhibition of Erk1/2 activity. We hypothesized that LAP3 promoted tumor migration and invasion by upregulating vimentin. The knockdown of vimentin resulted in the inhibited migration and invasion of MDA-MB-231 and MDA-MB-468 cells. The expression of MMP-2/9 and fascin could also be downregulated. In conclusion, vimentin might play an important role in the promotion of breast cancer metastasis by LAP3.