血清外泌体赖氨酰氧化酶样蛋白 2 升高是头颈部鳞状细胞癌的一个潜在生物标志物。

Elevated exosomal lysyl oxidase like 2 is a potential biomarker for head and neck squamous cell carcinoma.

机构信息

Department of Otorhinolaryngology-Head and Neck Surgery, Ehime University, Ehime, Japan.

Department of Molecular and Cellular Physiology, Ehime University, Ehime, Japan.

出版信息

Laryngoscope. 2020 May;130(5):E327-E334. doi: 10.1002/lary.28142. Epub 2019 Jun 20.

DOI:10.1002/lary.28142

PMID:31219623

Abstract

OBJECTIVES

The secretory enzyme lysyl oxidase like 2 (LOXL2) is speculated to contribute to tumor progression through its functions in the remodeling of extracellular matrix and epithelial-mesenchymal transition. We previously identified elevated expression of LOXL2 in metastatic human head and neck squamous cell carcinoma (HNSCC) cells in a mouse lymph node metastases model. Here we performed a case series study examining LOXL2 expression levels in human serum from HNSCC patients to evaluate whether LOXL2 is worth evaluation in a large cohort study.

METHODS

LOXL2 protein levels in three serum samples from HNSCC patients were assessed by immunoblotting and LOXL2 tissue expression was examined in one human tongue squamous cell carcinoma (SCC) tissue by immunohistochemistry as a representative of HNSCC tissue. Serum samples were further fractionated in exosomes and supernatants by ultracentrifugation, which were then subjected to immunoblot and in vitro LOX activity analyses. Exosomal LOXL2 levels of 36 serum samples from HNSCC patients and seven healthy volunteers were measured using polymer sedimentation exosome preparation followed by ELISA measurement and subjected to statistical analyses.

RESULTS

Immunoblot analyses revealed that LOXL2 was present in serum exosomal fractions from three HNSCC patients, and we observed approximately threefold higher levels of LOXL2 in HNSCC patients compared with three healthy volunteers. Immunohistochemical LOXL2 staining was detected in HNSCC cells in addition to non-cancerous lipid tissues and some muscles in human tongue HNSCC tissue. Further measurements of exosomal LOXL2 by ELISA showed over ninefold higher mean LOXL2 levels in patients compared with controls. Statistical analysis revealed a correlation between elevated serum exosomal LOXL2 levels and low-grade, but not high-grade, HNSCC.

CONCLUSIONS

Our case series study that elevated serum exosomal LOXL2 levels exhibited a correlation with low-grade HNSCCs. A follow-up large cohort clinical study will be required to determine the potential clinical utility of LOXL2 as a new biomarker and/or therapy target for HNSCCs.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:E327-E334, 2020.

摘要

目的

分泌酶赖氨酰氧化酶样 2（LOXL2）被推测通过其在细胞外基质重塑和上皮-间充质转化中的功能促进肿瘤进展。我们之前在小鼠淋巴结转移模型中发现转移性人头颈部鳞状细胞癌（HNSCC）细胞中 LOXL2 的表达升高。在这里，我们进行了一项病例系列研究，检测 HNSCC 患者血清中的 LOXL2 表达水平，以评估 LOXL2 是否值得在大样本队列研究中进行评估。

方法

通过免疫印迹评估 3 例 HNSCC 患者血清中的 LOXL2 蛋白水平，并通过免疫组织化学检测人舌鳞状细胞癌（SCC）组织中 LOXL2 的组织表达，作为 HNSCC 组织的代表。通过超速离心将血清样本进一步分为外泌体和上清液，然后进行免疫印迹和体外 LOX 活性分析。使用聚合物沉淀外泌体制备法测量 36 例 HNSCC 患者和 7 例健康志愿者的血清样本中的外泌体 LOXL2 水平，并进行 ELISA 测量和统计学分析。

结果

免疫印迹分析显示 LOXL2 存在于 3 例 HNSCC 患者的血清外泌体部分，与 3 例健康志愿者相比，我们观察到 HNSCC 患者的 LOXL2 水平约高 3 倍。免疫组织化学 LOXL2 染色除了非癌性脂质组织和人舌 HNSCC 组织中的一些肌肉外，还在 HNSCC 细胞中检测到。通过 ELISA 进一步测量外泌体 LOXL2 显示患者的 LOXL2 水平比对照组高 9 倍以上。统计学分析显示，血清外泌体 LOXL2 水平升高与低级别而非高级别 HNSCC 相关。