Division of Pathology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy.
EBioMedicine. 2019 Mar;41:225-235. doi: 10.1016/j.ebiom.2019.01.051. Epub 2019 Feb 6.
The V-ATPase proton pump controls acidification of intra and extra-cellular milieu in both physiological and pathological conditions. We previously showed that some V-ATPase subunits are enriched in glioma stem cells and in patients with poor survival. In this study, we investigated how expression of a GBM-like V-ATPase pump influences the non-neoplastic brain microenvironment.
Large oncosome (LO) vesicles were isolated from primary glioblastoma (GBM) neurospheres, or from patient sera, and co-cultured with primary neoplastic or non-neoplastic brain cells. LO transcript and protein contents were analyzed by qPCR, immunoblotting and immunogold staining. Activation of pathways in recipient cells was determined at gene and protein expression levels. V-ATPase activity was impaired by Bafilomycin A1 or gene silencing.
GBM neurospheres influence their non-neoplastic microenvironment by delivering the V-ATPase subunit V1G1 and the homeobox genes HOXA7, HOXA10, and POU3F2 to recipient cells via LO. LOs reprogram recipient cells to proliferate, grow as spheres and to migrate. Moreover, LOs are particularly abundant in the circulation of GBM patients with short survival time. Finally, impairment of V-ATPase reduces LOs activity.
We identified a novel mechanism adopted by glioma stem cells to promote disease progression via LO-mediated reprogramming of their microenvironment. Our data provide preliminary evidence for future development of LO-based liquid biopsies and suggest a novel potential strategy to contrast glioma progression. FUND: This work was supported by Fondazione Cariplo (2014-1148 to VV) and by the Italian Minister of Health-Ricerca Corrente program 2017 (to SF).
V-ATPase 质子泵在生理和病理条件下控制细胞内外环境的酸化。我们之前的研究表明，一些 V-ATPase 亚基在神经胶质瘤干细胞和生存预后较差的患者中富集。在这项研究中，我们研究了 GBM 样 V-ATPase 泵的表达如何影响非肿瘤性脑微环境。
从原发性神经胶质瘤（GBM）神经球或患者血清中分离出大 Oncosome（LO）囊泡，并与原代肿瘤或非肿瘤脑细胞共培养。通过 qPCR、免疫印迹和免疫金染色分析 LO 的转录物和蛋白质含量。通过 Bafilomycin A1 或基因沉默来测定受体细胞中途径的激活。
GBM 神经球通过 LO 将 V-ATPase 亚基 V1G1 和同源盒基因 HOXA7、HOXA10 和 POU3F2 递送至受体细胞，从而影响其非肿瘤微环境。LO 使受体细胞重新编程为增殖、生长为球体和迁移。此外，LO 在生存时间短的 GBM 患者的循环中特别丰富。最后，V-ATPase 的损伤降低了 LO 的活性。
我们发现了一种新的机制，即神经胶质瘤干细胞通过 LO 介导的微环境重编程来促进疾病进展。我们的数据为未来基于 LO 的液体活检的发展提供了初步证据，并提出了一种新的潜在策略来对抗神经胶质瘤的进展。
这项工作得到了 Cariplo 基金会（2014-1148 给 VV）和意大利卫生部“研究现行项目”（2017 给 SF）的支持。
