Abstract 570: The role of CD5L in chronic liver disease

Abstract

Abstract Macrophage migration inhibitory factor (MIF) is a CD5 molecule like glycoprotein synthesized and secreted by macrophages, also termed CD5L. In liver cancer, serum levels of CD5L has been reported to be higher in steatohepatitis and hepatocellular carcinoma (HCC) patients and proposed to be a serum marker for these conditions. In the liver, steatosis and steatohepatitis is a major comorbid factor for HCC development and associated with poor response to therapy, particularly immune-checkpoint therapy. Here, we assessed the levels of CD5L in plasma samples from 50 advanced HCC patients obtained at baseline prior to initiation of systemic immunotherapy and compared them with that of healthy controls. The data demonstrated a 50% higher plasma CD5L levels in HCC patients vs. healthy donors. Furthermore, CD5L concentrations are higher in patients with higher Child Pugh score. In patients treated with immune checkpoint single or combination therapy, serum CD5L was found to correlate with clinical benefit. To address the role of CD5L and CD5L secreting macrophage in HCC development, we performed in-silico analysis of single cell RNA-seq data and identified Cd5l as a unique gene expressed on liver resident macrophages, the Kupffer cells (KCs). This finding was validated with additional datasets and using two steatosis mouse models representing ALD and NAFLD. Furthermore, our immunofluorescent staining and flow cytometry further confirmed the main source of Cd5l is KCs. In HFD fed mice, we showed that the expression and serum levels of CD5L became more significant with the severity of liver injury, particularly steatotic liver injury. We hypothesize that CD5L may be involved in establish the tumor microenvironment established by steatohepatitis, we performed a free fatty acid (FFA) uptake assay and found that CD5L increased the uptake of FFA in hepatic stellate cells. This ability of CD5L may have contributed to therapy resistance observed in the CD5L high patients who showed reduced clinical benefit. Citation Format: Handan Hong, Taojian Tu, Lina He, Meisam Razaviyayn, Sze-Chuan Suan, Liyun Yuan, Bangyan L. Stiles. The role of CD5L in chronic liver disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 570.