The role of Myeloid cells in pediatric-high grade gliomas

摘要：MPI R 01- Hambardzumyan和Becher 儿童高级别胶质瘤（pHGG）占儿童癌症相关死亡的比例最高， 存活12-15个月。一个有希望的研究途径是开发针对 肿瘤内的非肿瘤细胞类型的性质，例如骨髓细胞，包括肿瘤相关的 巨噬细胞（TAM）和嗜中性粒细胞。我们对成人高级别胶质瘤中的TAM了解很多。可是 对pHGG中的TAM和嗜中性粒细胞知之甚少。pHGG更常见于幕下部位 就像脑干一样，在成年人的大脑半球之外。pHGG还含有不同的组蛋白 在成年人中没有发现的突变。这就提出了一个问题，即pHGG是否拥有一个独特的选区， TAM由于其独特的遗传景观和位置。 使用人类pHGG组织样本和NanoString RNA测序，我们证明了脑干/中线 pHGG（DMG）和鼠弥漫性内在脑桥胶质瘤（DIPG）具有较高的炎症评分， 与半球pHGG相比，增加的中性粒细胞评分与较短的患者生存期相关。 当仅检查人类半球pHGG时，我们的结果显示了两个患者亚组， 炎症评分。炎症评分高的患者的生存时间明显短于 炎症评分低的人。我们还表明，人pHGG具有较高的IBA 1+浸润， TAM是pHGG肿瘤微环境（TME）中最丰富的非肿瘤成分。 我们的初步数据利用小鼠模型来概括新生免疫活性小鼠中的pHGG， 在生物学相关位置的各种组蛋白突变表明小鼠肿瘤惊人地相似 在炎症免疫特征和骨髓细胞浸润方面与人类对应物相比。使用 PDGFB和PDGFA作为驱动突变在小鼠中产生半球pHGG，我们能够概括 具有高和低炎症评分的人pHGG。我们发现，与PDGFA驱动的肿瘤相比， PDGFB肿瘤具有更高的炎症评分，增加的单核细胞从血液中浸润，以及更短的时间。 荷瘤小鼠的存活时间。我们确定CCL 3是CCR 1/CCR 5阳性细胞的潜在关键趋化因子。 单核细胞和CXCL 1用于pHGG中CXCR 2阳性中性粒细胞募集。总之，这些结果提供了 强有力的理由来扩展我们的研究，以了解特定的组蛋白突变和肿瘤位置如何影响 骨髓细胞浸润以及这些细胞如何促进pHGG生长。这些研究的结果将：（一）揭示 pHGG的髓样区室的分子和功能多样性;（ii）确定髓样区室的不同 亚群和骨髓特异性基因影响肿瘤生长和TME;（iii）提供骨髓 亚群影响驱动突变、儿科特异性组蛋白突变和肿瘤位置， （半球与脑干）。这项研究还将确定是否靶向单核细胞和中性粒细胞， 渗透将是在pHGG中开发的可行的治疗途径。

Abstract: MPI R01- Hambardzumyan and Becher Pediatric high-grade gliomas (pHGG) account for the most cancer-related deaths in children and have a median survival of 12-15 months. One promising avenue of research is developing novel therapies targeting the properties of non-neoplastic cell types within the tumor, such as myeloid cells, including tumor-associated macrophages (TAMs) and neutrophils. Much is known about TAMs in adult high-grade gliomas. However, very little is known about TAMs and neutrophils in pHGGs. pHGGs more commonly arise in infratentorial locations like the brainstem, beyond the cerebral hemispheres as seen in adults. pHGGs also harbor distinct histone mutations not found in adults. This raises the question of whether pHGGs possess a distinct constituency of TAMs due to their unique genetic landscapes and locations. Using human pHGG tissue samples and NanoString RNA sequencing, we demonstrate brainstem/midline pHGGs (DMG) and murine diffuse intrinsic pontine glioma (DIPG) possess higher inflammatory scores and increased neutrophil scores compared to hemispheric pHGGs, which are associated with shorter patient survival. When examining only human hemispheric pHGGs, our results revealed two patient subsets with high and low inflammatory scores. Patients with a high inflammatory score had significantly shorter survival times compared to those with low inflammatory scores. We also show that human pHGGs possess high infiltration of IBA1+ TAMs, which are the most abundant non-neoplastic component of the pHGG tumor microenvironment (TME). Our preliminary data utilizing mouse models to recapitulate pHGG in newborn immunocompetent mice combined with various histone mutations in biologically relevant locations demonstrate murine tumors are strikingly similar to their human counterparts with regard to their inflammatory immune profile and myeloid cell infiltration. Using PDGFB and PDGFA as driver mutations to generate hemispheric pHGG in mice, we were able to recapitulate human pHGGs with high and low inflammatory scores. We showed that in comparison to PDGFA-driven tumors, PDGFB tumors have a higher inflammatory score, increased infiltration of monocytes from the blood, and shorter survival time of tumor-bearing mice. We identify CCL3 as a potential key chemokine for CCR1/CCR5-positive monocytes and CXCL1 for CXCR2-positive neutrophil recruitment in pHGG. Together, these results provide strong rationale to extend our studies to understand how specific histone mutations and tumor locations influence myeloid cell infiltration and how these cells promote pHGG growth. The outcome of these studies will: (i) reveal the molecular and functional diversity of the myeloid compartment of pHGG; (ii) determine how distinct myeloid subsets and myeloid-specific genes influence tumor growth and the TME; (iii) provide insight into how myeloid subsets influence, and are affected by driver mutations, pediatric-specific histone mutations, and tumor location (hemisphere versus brainstem). This study will also determine whether targeting monocyte and neutrophil infiltration will be a viable therapeutic avenue for exploitation in pHGG.