Department of Oncology, University of Torino, via Santena 5/bis, 10126, Torino Italy.
Department of Drug Science and Technology, University of Torino, via Pietro Giuria 9, 10125, Torino, Italy.
Molecules. 2018 Jun 9;23(6):1401. doi: 10.3390/molecules23061401.
P-glycoprotein (Pgp) determines resistance to a broad spectrum of drugs used against glioblastoma multiforme (GB). Indeed, Pgp is highly expressed in GB stem cells and in the brain-blood barrier (BBB), the peculiar endothelium surrounding the brain. Inhibiting Pgp activity in the BBB and GB is still an open challenge. Here, we tested the efficacy of a small library of tetrahydroisoquinoline derivatives with an EC for Pgp ≤ 50 nM, in primary human BBB cells and in patient-derived GB samples, from which we isolated differentiated/adherent cells (AC, i.e., Pgp-negative/doxorubicin-sensitive cells) and stem cells (neurospheres, NS, i.e., Pgp-positive/doxorubicin-resistant cells). Three compounds used at 1 nM increased the delivery of doxorubicin, a typical substrate of Pgp, across BBB monolayer, without altering the expression and activity of other transporters. The compounds increased the drug accumulation within NS, restoring doxorubicin-induced necrosis and apoptosis, and reducing cell viability. In co-culture systems, the compounds added to the luminal face of BBB increased the delivery of doxorubicin to NS growing under BBB and rescued the drug’s cytotoxicity. Our work identified new ligands of Pgp active at low nanomolar concentrations. These compounds reduce Pgp activity in BBB and GB and improve in vitro chemotherapy efficacy in this tumor.
P-糖蛋白（Pgp）决定了多形性胶质母细胞瘤（GB）的广谱药物的耐药性。事实上，Pgp 在 GB 干细胞和血脑屏障（BBB）中高度表达，BBB 是环绕大脑的特殊内皮。抑制 BBB 和 GB 中的 Pgp 活性仍然是一个悬而未决的挑战。在这里，我们测试了一组 EC50 对 Pgp≤50 nM 的四氢异喹啉衍生物的功效，这些衍生物在原代人 BBB 细胞和患者来源的 GB 样本中进行了测试，我们从这些样本中分离出分化/贴壁细胞（AC，即 Pgp 阴性/阿霉素敏感细胞）和干细胞（神经球，NS，即 Pgp 阳性/阿霉素耐药细胞）。三种在 1 nM 下使用的化合物增加了阿霉素（Pgp 的典型底物）穿过 BBB 单层的递送，而不改变其他转运体的表达和活性。这些化合物增加了 NS 内的药物积累，恢复了阿霉素诱导的坏死和凋亡，并降低了细胞活力。在共培养系统中，添加到 BBB 管腔面的化合物增加了在 BBB 下生长的 NS 中阿霉素的递送，并挽救了药物的细胞毒性。我们的工作确定了新的 Pgp 低纳摩尔浓度的活性配体。这些化合物降低了 BBB 和 GB 中的 Pgp 活性，并提高了这种肿瘤的体外化疗疗效。
