Abstract P5-05-08: CXCL16 as a potential therapeutic target of triple-negative breast cancer

Abstract

Abstract CXCL16, as a chemotactic cytokine, promotes cancer proliferation, migration, and immune cell infiltration in tumor microenvironment. However, CXCL16 has been shown to play a conflicting role in breast cancer. The aim of this study was to investigate the therapeutic potential of CXCL16 in breast cancer. Breast cancer patients (n=1097) from the TCGA dataset were divided into two group according to the CXCL16 expressions, the CXCL16low (n=548) and the CXCLhigh (n=549) groups. Mean diagnostic ages were similar between groups (59 ± 13.5 vs 58 ± 12.9 years, P=0.233). The ratio of triple-negative breast cancer (TNBC) was significantly higher in the CXCLhigh than that of the CXCL16low groups (24.8 vs 6.8%, P<0.001), while the presence of distant metastasis or overall survivals were not different between groups. Interestingly, gene scoring analysis showed that oncogenic molecules including M2-macrophage- (r=0.36, P<0.001), efferocytosis- (r=0.42, P<0.001), and chemokine- (r=0.46, P<0.001) related gene sets showed significantly strong positive relations with the CXCL16 expressions in all patients including both TNBC (n=924) and non-TNBC (n=173). Additionally, the gene set score from PI3K/Akt pathway showed positive relation with the CXCL16 expressions in the non-TNBC (r=022, P<0.001) but not in the TNBC group. Next, a xenograft mouse model of TNBC was established with MDA-MB-231 cells, and anti-mouse CXCL16 antibody (designated as aCXCL16 group) or control IgG (designated as control group) were intravenously injected (25µg/100µl), twice per week. During 3 weeks, tumor growth was significantly delayed in the aCXCL16 than the control group by 37%. In conclusion, CXCL16 is highly expressed in TNBC and positively correlates with M2-macrophage related genes. Neutralizing CXCL16 by anti-CXCL16 shows therapeutic effects on the xenograft model of TNBC, suggesting that CXCL16 can be a potential therapeutic target for breast cancer. Citation Format: Sun Wook Cho, Mi Gyeong Jang, Hyun Jin Sun, Han Sai Lee, Young Shin Song, Seong Keun Kim. CXCL16 as a potential therapeutic target of triple-negative breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-05-08.