Pizzocri Marco, Re Francesca, Stanzani Elisabetta, Formicola Beatrice, Tamborini Matteo, Lauranzano Eliana, Ungaro Federica, Rodighiero Simona, Francolini Maura, Gregori Maria, Perin Alessandro, DiMeco Francesco, Masserini Massimo, Matteoli Michela, Passoni Lorena
IRCCS Humanitas Research Hospital, Laboratory of Pharmacology and Brain Pathology, via Manzoni 56, 20089 Rozzano, Milano, Italy.
BioNanoMedicine Center NANOMIB, School of Medicine and Surgery, University of Milano-Bicocca, via Raoul Follereau 3, 20854 Vedano al Lambro, Italy.
Neurooncol Adv. 2021 Jun 18;3(1):vdab076. doi: 10.1093/noajnl/vdab076. eCollection 2021 Jan-Dec.
The radio- and chemo-resistance of glioblastoma stem-like cells (GSCs), together with their innate tumor-initiating aptitude, make this cell population a crucial target for effective therapies. However, targeting GSCs is hardly difficult and complex, due to the presence of the blood-brain barrier (BBB) and the infiltrative nature of GSCs arousing their dispersion within the brain parenchyma.
Liposomes (LIPs), surface-decorated with an Apolipoprotein E-modified peptide (mApoE) to enable BBB crossing, were loaded with doxorubicin (DOXO), as paradigm of cytotoxic drug triggering immunogenic cell death (ICD). Patient-derived xenografts (PDXs) obtained by GSC intracranial injection were treated with mApoE-DOXO-LIPs alone or concomitantly with radiation.
Our results indicated that mApoE, through the engagement of the low-density lipoprotein receptor (LDLR), promotes mApoE-DOXO-LIPs transcytosis across the BBB and confers target specificity towards GSCs. Irradiation enhanced LDLR expression on both BBB and GSCs, thus further promoting LIP diffusion and specificity. When administered in combination with radiations, mApoE-DOXO-LIPs caused a significant reduction of in vivo tumor growth due to GSC apoptosis. GSC apoptosis prompted microglia/macrophage phagocytic activity, together with the activation of the antigen-presenting machinery crucially required for anti-tumor adaptive immune response.
Our results advocate for radiotherapy and adjuvant administration of drug-loaded, mApoE-targeted nanovectors as an effective strategy to deliver cytotoxic molecules to GSCs at the surgical tumor margins, the forefront of glioblastoma (GBM) recurrence, circumventing BBB hurdles. DOXO encapsulation proved in situ immune response activation within GBM microenvironment.
胶质母细胞瘤干细胞（GSCs）具有放射和化学抗性，以及固有的肿瘤起始能力，这使得该细胞群体成为有效治疗的关键靶点。然而，由于血脑屏障（BBB）的存在以及GSCs的浸润性导致它们在脑实质内分散，靶向GSCs极具难度且复杂。
用载脂蛋白E修饰肽（mApoE）进行表面修饰以实现血脑屏障穿越的脂质体（LIPs），装载了阿霉素（DOXO），DOXO是引发免疫原性细胞死亡（ICD）的细胞毒性药物范例。通过颅内注射GSCs获得的患者来源异种移植瘤（PDXs），单独用mApoE-DOXO-LIPs治疗或与放疗联合治疗。
我们的结果表明，mApoE通过低密度脂蛋白受体（LDLR）的结合，促进mApoE-DOXO-LIPs跨血脑屏障的转胞吞作用，并赋予对GSCs的靶向特异性。辐射增强了血脑屏障和GSCs上LDLR的表达，从而进一步促进脂质体的扩散和特异性。当与放疗联合使用时，mApoE-DOXO-LIPs由于GSC凋亡导致体内肿瘤生长显著减少。GSC凋亡促使小胶质细胞/巨噬细胞的吞噬活性，以及抗肿瘤适应性免疫反应所需的抗原呈递机制的激活。
我们的结果支持放疗以及辅助给予载药的、靶向mApoE的纳米载体，作为一种有效的策略，将细胞毒性分子递送至胶质母细胞瘤（GBM）复发前沿的手术肿瘤边缘的GSCs，绕过血脑屏障障碍。阿霉素包封证明在GBM微环境内激活原位免疫反应。
