Predictors of the CD24/CD11b Biomarker among Healthy Subjects

CD24 in Head and Neck Malignancies-An Uprising Biomarker?

INTRODUCTION

CD24 is often overexpressed in human tumors as a regulator of cell migration, invasion and proliferation. It has been associated with poor prognosis and chemoresistance in laryngeal cancer. In oral cavity tumors, it was correlated with better overall survival. In this study, we aimed to evaluate the role of CD24 in peripheral blood leukocytes (PBLs) as a potential marker for head and neck malignancies.

MATERIALS AND METHODS

CD24/CD11b expression in peripheral blood leukocytes (PBLs) of head and neck cancer patients and matched healthy controls was analyzed via flow cytometry. Tumors and healthy tissues were immune-stained for CD24 expression and the intensity of stain was ranked. Clinical data including tumor site, size, locoregional or metastatic spread, histopathological characteristics and recurrence events were analyzed.

RESULTS

CD24 expression in PBLs was significantly higher in a cohort of 101 head and neck cancer patients compared with 101 matched healthy controls (26.9 ± 12.9 vs. 22.4 ± 13.8; p = 0.02). No significant differences in CD24 levels in PBLs were found between different head and neck subsites involved with malignancy. Higher CD24 levels did not correlate with any adverse feature, i.e., perineural invasion or lymphovascular invasion, advanced T stage or regional spread. Immunohistochemistry analysis demonstrated that CD24 was highly expressed in tumor tissue in comparison to healthy surrounding tissue.

CONCLUSIONS

CD24 is a possible uprising marker for tumor identification, overexpressed in PBLs and is intensely stained in tumor tissue and pre-malignant lesions. Tumor-PBLs should be further studied.

CD24 blockade as a novel strategy for cancer treatment

The CD24 protein is a heat-stable protein with a small core that undergoes extensive glycosylation. It is expressed on the surface of various normal cells, including lymphocytes, epithelial cells, and inflammatory cells. CD24 exerts its function by binding to different ligands. Numerous studies have demonstrated the close association of CD24 with tumor occurrence and progression. CD24 not only facilitates tumor cell proliferation, metastasis, and immune evasion but also plays a role in tumor initiation, thus, serving as a marker on the surface of cancer stem cells (CSCs). Additionally, CD24 induces drug resistance in various tumor cells following chemotherapy. To counteract the tumor-promoting effects of CD24, several treatment strategies targeting CD24 have been explored, such as the use of CD24 monoclonal antibodies (mAb) alone, the combination of CD24 and chemotoxic drugs, or the combination of these drugs with other targeted immunotherapeutic techniques. Regardless of the approach, targeting CD24 has demonstrated significant anti-tumor effects. Therefore, the present study focuses on anti-tumor therapy and provides a comprehensive review of the structure and fundamental physiological function of CD24 and its impact on tumor development, and suggests that targeting CD24 may represent an effective strategy for treating malignant tumors.

CD24-Siglec axis is an innate immune checkpoint against metaflammation and metabolic disorder

The molecular interactions that regulate chronic inflammation underlying metabolic disease remain largely unknown. Since the CD24-Siglec interaction regulates inflammatory response to danger-associated molecular patterns (DAMPs), we have generated multiple mouse strains with single or combined mutations of Cd24 or Siglec genes to explore the role of the CD24-Siglec interaction in metaflammation and metabolic disorder. Here, we report that the CD24-Siglec-E axis, but not other Siglecs, is a key suppressor of obesity-related metabolic dysfunction. Inactivation of the CD24-Siglec-E pathway exacerbates, while CD24Fc treatment alleviates, diet-induced metabolic disorders, including obesity, dyslipidemia, insulin resistance, and nonalcoholic steatohepatitis (NASH). Mechanistically, sialylation-dependent recognition of CD24 by Siglec-E induces SHP-1 recruitment and represses metaflammation to protect against metabolic syndrome. A first-in-human study of CD24Fc (NCT02650895) supports the significance of this pathway in human lipid metabolism and inflammation. These findings identify the CD24-Siglec-E axis as an innate immune checkpoint against metaflammation and metabolic disorder and suggest a promising therapeutic target for metabolic disease.