血管周细胞在表达PDGF-B的实体瘤中诱发造血

背景与目的肿瘤组织持续生长需要红细胞充分供氧。在各类病理生理情况下,成年哺乳动物可在主要造血器官骨髓之外发生髓外造血。然而,肿瘤组织能否造血是完全未知的。大量证据表明,在肿瘤微环境中,血管周细胞保留了祖细胞特性,可分化成其他细胞类型。在此,我们探究了肿瘤组织内周细胞是否能调节造血及其作用机制。方法使用鼠源周细胞进行全基因组表达谱分析以测试周细胞是否可向红细胞分化。使用NG2-CreERT2:R26R-tdTomato小鼠对血管周细胞进行在体遗传示踪。使用流式细胞术、单细胞测序和集落形成实验对分选细胞进行鉴定。使用定量聚合酶链反应(quantitative polymerase chain reactionq,PCR)、酶联免疫吸附实验(enzyme-linked immunosorbent assay,ELISA)、细胞磁珠分选和免疫染色检查红细胞生成素(erythropoietin,EPO)的表达。构建骨髓移植小鼠模型以研究骨髓对肿瘤红细胞生成的影响。结果表达谱显示,在PDGF-B处理后,NG2+周细胞表现出造血干祖样特征,并向红系谱系分化。同时,PDGF-B可靶向癌症相关成纤维细胞以产生促红细胞生成的关键激素EPO。通过遗传示踪及流式分析,我们定义了NG2+细胞衍生的造血亚群。进一步的单细胞测序和集落形成实验结果显示,在PDGF-B刺激下,肿瘤中的NG2+细胞形成了与典型的骨髓造血干细胞不同的红系祖细胞。结论本研究提出了肿瘤组织内造血的新概念,并阐明肿瘤周细胞分化为红细胞的分子机制。靶向肿瘤造血作为一种新的治疗理念,可能对肿瘤治疗产生深远影响。

Perivascular localized cells commit erythropoiesis in PDGF-B-expressing solid tumors

Background:Tumors possess incessant growth features,and expansion of their masses demands sufficient oxygen supply by red blood cells(RBCs).In adult mammals,the bone marrow(BM)is the main organ regulating hematopoiesis with dedicated manners.Other than BM,extramedullary hematopoiesis is discovered in various pathophysiological settings.However,whether tumors can contribute to hematopoiesis is completely unknown.Accumulating evidence shows that,in the tumor microenvironment(TME),perivascular localized cells retain progenitor cell properties and can differentiate into other cells.Here,we sought to better understand whether and how perivascular localized pericytes in tumors manipulate hematopoiesis.Methods:To test if vascular cells can differentiate into RBCs,genome-wide expression profiling was performed using mouse-derived pericytes.Genetic tracing of perivascular localized cells employing NG2-CreERT2:R26R-tdTomato mouse strain was used to validate the findings in vivo.Fluorescence-activated cell sorting(FACS),single-cell sequencing,and colony formation assays were applied for biological studies.The production of erythroid differentiationspecific cytokine,erythropoietin(EPO),in TME was checked using quantitative polymerase chain reaction(qPCR),enzyme-linked immunosorbent assay(ELISA,magnetic-activated cell sorting and immunohistochemistry.To investigate BM function in tumor erythropoiesis,BM transplantation mouse models were employed.Results:Genome-wide expression profiling showed that in response to plateletderived growth factor subunit B(PDGF-B),neural/glial antigen 2(NG2)+perivascular localized cells exhibited hematopoietic stem and progenitor-like features and underwent differentiation towards the erythroid lineage.PDGF-B simultaneously targeted cancer-associated fibroblasts to produce high levels of EPO,a crucial hormone that necessitates erythropoiesis.FACS analysis using genetic tracing of NG2+cells in tumors defined the perivascular localized cell-derived subpopulation of hematopoietic cells.Single-cell sequencing and colony formation assays validated the fact that,upon PDGF-B stimulation,NG2+cells isolated from tumors acted as erythroblast progenitor cells,which were distinctive from the canonical BM hematopoietic stem cells.Conclusions:Our data provide a new concept of hematopoiesis within tumor tissues and novel mechanistic insights into perivascular localized cell-derived erythroid cells within TME.Targeting tumor hematopoiesis is a novel therapeutic concept for treating various cancers that may have profound impacts on cancer therapy.