Department of Cancer Biology and Comprehensive Cancer Center, Wake Forest University Health Sciences, Winston-Salem, NC, USA.
Internal Medicine-Sections in Pulmonary and Critical Care Medicine and Geriatrics and the Critical Illness Injury and Recovery Research Center, Wake Forest University Health Sciences, Winston-Salem, NC, USA.
J Cachexia Sarcopenia Muscle. 2021 Aug;12(4):1079-1097. doi: 10.1002/jcsm.12714. Epub 2021 May 18.
Eighty per cent of United States advanced cancer patients faces a worsened prognosis due to cancer-associated cachexia. Inflammation is one driver of muscle atrophy in cachexia, and skeletal muscle-resident immune cells could be a source of inflammation. This study explores the efficacy of cancer activated skeletal muscle-resident mast cells as a biomarker and mediator of cachexia.
Individual gene markers for immune cells were assessed in a publicly available colon carcinoma cohort of normal (n = 3), moderate cachexia (n = 3), and severe cachexia (n = 4) mice. Lewis lung carcinoma (LL/2) cells induced cachexia in C57BL/6 mice, and a combination of toluidine blue staining, immunofluorescence, quantitative polymerase chain reaction, and western blots measured innate immune cell expression in hind limb muscles. In vitro measurements included C2C12 myotube diameter before and after treatment with media from primary murine mast cells activated with LL/2 conditioned media. To assess translational potential in human samples, innate immune cell signatures were assessed for correlation with skeletal muscle atrophy and apoptosis, dietary excess, and cachexia signatures in normal skeletal muscle tissue. Gene set enrichment analysis was performed with innate immune cell signatures in publicly available cohorts for upper gastrointestinal (GI) cancer and pancreatic ductal adenocarcinoma (PDAC) patients (accession: GSE34111 and GSE130563, respectively).
Individual innate immunity genes (TPSAB1 and CD68) showed significant increases in severe cachexia (weight loss > 15%) mice in a C26 cohort (GSE24112). Induction of cachexia in C57BL/6 mice with LL/2 subcutaneous injection significantly increased the number of activated skeletal muscle-resident degranulating mast cells. Murine mast cells activated with LL/2 conditioned media decreased C2C12 myotube diameter (P ≤ 0.05). Normal human skeletal muscle showed significant positive correlations between innate immune cell signatures and muscle apoptosis and atrophy, dietary excess, and cachexia signatures. The mast cell signature was up-regulated (positive normalized enrichment score and false discovery rate ≤ 0.1) in upper GI cachectic patients (n = 12) compared with control (n = 6), as well as in cachectic PDAC patients (n = 17) compared with control patients (n = 16).
Activated skeletal muscle-resident mast cells are enriched in cachectic muscles, suggesting skeletal-muscle resident mast cells may serve as a biomarker and mediator for cachexia development to improve patient diagnosis and prognosis.
80%的美国晚期癌症患者由于癌症相关性恶病质而预后恶化。炎症是恶病质中肌肉萎缩的一个驱动因素，而骨骼肌驻留免疫细胞可能是炎症的来源。本研究探讨了癌症激活的骨骼肌驻留肥大细胞作为恶病质的生物标志物和介质的功效。
在公开的结肠癌正常（n=3）、中度恶病质（n=3）和重度恶病质（n=4）小鼠队列中评估了免疫细胞的单个基因标志物。Lewis 肺癌（LL/2）细胞在 C57BL/6 小鼠中诱导恶病质，并用甲苯胺蓝染色、免疫荧光、定量聚合酶链反应和 Western blot 测量后肢肌肉中固有免疫细胞的表达。体外测量包括用用 LL/2 条件培养基激活的原代鼠肥大细胞培养基处理前后 C2C12 肌管的直径。为了评估在人类样本中的转化潜力，评估了固有免疫细胞特征与骨骼肌萎缩和凋亡、饮食过量以及正常骨骼肌组织中的恶病质特征之间的相关性。使用公开队列中用于上消化道（GI）癌症和胰腺导管腺癌（PDAC）患者的固有免疫细胞特征进行基因集富集分析（访问号：GSE34111 和 GSE130563）。
在 C26 队列（GSE24112）中，单个固有免疫基因（TPSAB1 和 CD68）在体重减轻>15%的重度恶病质（n=3）小鼠中显著增加。用 LL/2 皮下注射诱导 C57BL/6 小鼠恶病质显着增加了激活的骨骼肌驻留脱颗粒肥大细胞的数量。用 LL/2 条件培养基激活的鼠肥大细胞可降低 C2C12 肌管的直径（P≤0.05）。正常人类骨骼肌中固有免疫细胞特征与肌肉凋亡和萎缩、饮食过量和恶病质特征之间存在显著正相关。与对照组（n=6）相比，上消化道恶病质患者（n=12）和与对照组患者（n=16）相比，恶病质 PDAC 患者（n=17）的肥大细胞特征上调（正标准化富集评分和错误发现率≤0.1）。
激活的骨骼肌驻留肥大细胞在恶病质肌肉中富集，这表明骨骼肌驻留肥大细胞可能作为恶病质发展的生物标志物和介质，以改善患者的诊断和预后。
