Laboratoire d'Oncologie Moléculaire, Centre de Recherche CERMO-FC, Département de Chimie, Université du Québec à Montréal, Montréal, QC H3C 3P8, Canada.
Int J Mol Sci. 2022 Nov 17;23(22):14214. doi: 10.3390/ijms232214214.
Modulations in cell surface receptor ectodomain proteolytic shedding impact on receptor function and cancer biomarker expression. As such, heavily pursued therapeutic avenues have exploited LDL receptor-related protein-1 (LRP-1)-mediated capacity in internalizing Angiopep-2 (An2), a brain-penetrating peptide that allows An2-drug conjugates to cross the blood-brain tumor barrier (BBTB). Given that LRP-1 is proteolytically shed from the cell surface through matrix metalloproteinase (MMP) activity, the balance between MMP expression/function and LRP-1-mediated An2 internalization is unknown. In this study, we found that membrane type-1 (MT1)-MMP expression increased from grade 1 to 4 brain tumors, while that of LRP-1 decreased inversely. MMP pharmacological inhibitors such as Ilomastat, Doxycycline and Actinonin increased in vitro An2 internalization by up to 2.5 fold within a human grade IV-derived U87 glioblastoma cell model. Transient siRNA-mediated MT1-MMP gene silencing resulted in increased basal An2 cell surface binding and intracellular uptake, while recombinant MT1-MMP overexpression reduced both cell surface LRP-1 expression as well as An2 internalization. The addition of Ilomastat to cells overexpressing recombinant MT1-MMP restored LRP-1 expression at the cell surface and An2 uptake to levels comparable to those observed in control cells. Collectively, our data suggest that MT1-MMP expression status dictates An2-mediated internalization processes in part by regulating cell surface LRP-1 functions. Such evidence prompts preclinical evaluations of combined MMP inhibitors/An2-drug conjugate administration to potentially increase the treatment of high-MT1-MMP-expressing brain tumors.
细胞表面受体胞外结构域蛋白水解脱落的调节会影响受体功能和癌症生物标志物的表达。因此，人们大力探索治疗途径，利用 LDL 受体相关蛋白-1（LRP-1）介导的内吞作用来内化血管生成肽-2（An2），这是一种穿透血脑屏障（BBTB）的肽，使 An2-药物偶联物能够穿越血脑肿瘤屏障。鉴于 LRP-1 通过基质金属蛋白酶（MMP）活性从细胞表面进行蛋白水解脱落，因此 MMP 表达/功能与 LRP-1 介导的 An2 内化之间的平衡尚不清楚。在这项研究中，我们发现膜型-1（MT1）-MMP 的表达从 1 级到 4 级脑肿瘤增加，而 LRP-1 的表达则相反。MMP 药理学抑制剂，如伊洛马司他、强力霉素和放线菌素，在人 4 级衍生的 U87 神经胶质瘤细胞模型中，可将体外 An2 内化增加高达 2.5 倍。瞬时 siRNA 介导的 MT1-MMP 基因沉默导致基础 An2 细胞表面结合和细胞内摄取增加，而重组 MT1-MMP 过表达则降低细胞表面 LRP-1 表达和 An2 内化。在过表达重组 MT1-MMP 的细胞中加入伊洛马司他，可恢复细胞表面 LRP-1 表达，并将 An2 摄取恢复到与对照细胞相当的水平。总之，我们的数据表明，MT1-MMP 的表达状态决定了 An2 介导的内化过程，部分原因是调节细胞表面 LRP-1 的功能。这种证据提示进行 MMP 抑制剂/An2-药物偶联物联合给药的临床前评估，以潜在地增加对高 MT1-MMP 表达脑肿瘤的治疗效果。
