Glioblastomas (GB) are brain tumours with poor prognosis even after aggressive therapy. Improvements in both therapeutic and follow-up strategies are urgently needed. In previous work we described an oscillatory pattern of response to Temozolomide (TMZ) using a standard administration protocol, detected through MRSI-based machine learning approaches. In the present work, we have introduced the Immune-Enhancing Metronomic Schedule (IMS) with an every 6-d TMZ administration at 60 mg/kg and investigated the consistence of such oscillatory behaviour. A total of n = 17 GL261 GB tumour-bearing C57BL/6j mice were studied with MRI/MRSI every 2 d, and the oscillatory behaviour (6.2 ± 1.5 d period from the TMZ administration day) was confirmed during response. Furthermore, IMS-TMZ produced significant improvement in mice survival (22.5 ± 3.0 d for controls vs 135.8 ± 78.2 for TMZ-treated), outperforming standard TMZ treatment. Histopathological correlation was investigated in selected tumour samples (n = 6) analyzing control and responding fields. Significant differences were found for CD3+ cells (lymphocytes, 3.3 ± 2.5 vs 4.8 ± 2.9, respectively) and Iba-1 immunostained area (microglia/macrophages, 16.8% ± 9.7% and 21.9% ± 11.4%, respectively). Unexpectedly, during IMS-TMZ treatment, tumours from some mice (n = 6) fully regressed and remained undetectable without further treatment for 1 mo. These animals were considered "cured" and a GL261 re-challenge experiment performed, with no tumour reappearance in five out of six cases. Heterogeneous therapy response outcomes were detected in tumour-bearing mice, and a selected group was investigated (n = 3 non-responders, n = 6 relapsing tumours, n = 3 controls). PD-L1 content was found ca. 3-fold increased in the relapsing group when comparing with control and non-responding groups, suggesting that increased lymphocyte inhibition could be associated to IMS-TMZ failure. Overall, data suggest that host immune response has a relevant role in therapy response/escape in GL261 tumours under IMS-TMZ therapy. This is associated to changes in the metabolomics pattern, oscillating every 6 d, in agreement with immune cycle length, which is being sampled by MRSI-derived nosological images.

中文翻译：

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通过基于MRSI的疾病影像学监测的替莫唑胺增强免疫节律计划产生的GL261胶质母细胞瘤中的抗肿瘤免疫反应。

胶质母细胞瘤（GB）是即使经过积极治疗也预后较差的脑肿瘤。迫切需要改善治疗和随访策略。在以前的工作中，我们描述了使用基于MRSI的机器学习方法检测到的使用标准给药方案对替莫唑胺（TMZ）的响应的振荡模式。在目前的工作中，我们以60 mg / kg的剂量每6 d TMZ引入了一种免疫增强节拍方案（IMS），并研究了这种振荡行为的一致性。每隔2 d用MRI / MRSI研究n = 17只GL261 GB荷瘤的C57BL / 6j小鼠，并在应答期间确认其振荡行为（从TMZ给药日起6.2±1.5 d）。此外，IMS-TMZ显着提高了小鼠的存活率（22.5±3）。对照组为0 d，TMZ处理为135.8±78.2），优于标准TMZ处理。在选定的肿瘤样本（n = 6）中研究组织病理学相关性，分析对照和反应场。发现CD3 +细胞（淋巴细胞分别为3.3±2.5 vs 4.8±2.9）和Iba-1免疫染色区域（小胶质细胞/巨噬细胞分别为16.8％±9.7％和21.9％±11.4％）存在显着差异。出乎意料的是，在IMS-TMZ治疗期间，某些小鼠（n = 6）的肿瘤完全消退，并且未经进一步治疗1个月仍无法检测到。这些动物被认为是“治愈的”，并且进行了GL261再挑战实验，在六分之五的病例中没有肿瘤再出现。检测了荷瘤小鼠的异质治疗反应结果，并调查了一个选定的组（n = 3个无反应者，n = 6个复发性肿瘤，n = 3个对照）。大约发现PD-L1含量。与对照组和非应答组相比，复发组增加了3倍，表明淋巴细胞抑制作用增加可能与IMS-TMZ失败有关。总体而言，数据表明宿主免疫应答在IMS-TMZ治疗下对GL261肿瘤的治疗应答/逃逸中具有相关作用。这与代谢组学模式的变化有关，该变化每6 d振荡一次，与免疫周期的长度一致，该免疫周期的长度已由MRSI衍生的疾病影像进行采样。数据表明，在IMS-TMZ治疗下，宿主免疫应答在GL261肿瘤的治疗应答/逃逸中具有重要作用。这与代谢组学模式的变化有关，该变化每6 d振荡一次，与免疫周期的长度一致，该免疫周期的长度已由MRSI衍生的疾病影像进行采样。数据表明，在IMS-TMZ治疗下，宿主免疫应答在GL261肿瘤的治疗应答/逃逸中具有重要作用。这与代谢组学模式的变化有关，该变化每6 d振荡一次，与免疫周期的长度一致，该免疫周期的长度已由MRSI衍生的疾病影像进行采样。