Extracellular ubiquitin promotes hepatoma metastasis by mediating M2 macrophage polarization via the activation of the CXCR4/ERK signaling pathway

Abstract

Background: Stored red blood cell (RBC) transfusion has been shown to enhance the risk of cancer recurrence. However, the underlying mechanism remains unknown. At our lab, we have demonstrated that the extracellular ubiquitin (eUb) released by aged RBCs could promote tumor metastasis in a melanoma mouse model. This study aimed to confirm the pro-tumor effect of eUb on hepatocellular carcinoma (HCC) and explore the related immunoregulatory mechanisms.Methods: Forty HCC tissue specimens and the corresponding adjacent nontumor and normal liver tissues were collected. Two human hepatoma cell lines (MHCC-97H and HepG2.2.15), one murine hepatoma cell line (Hepa1-6), and one human monocyte cell line (THP-1) were adopted in this study. The coculture of hepatoma cells with macrophages was initiated with Transwell inserts. Cell migration in vitro was detected by Transwell and wound-healing assays, while in vivo tumor metastasis was measured by luciferase assay and H&E staining. Macrophage polarization was measured by flow cytometry, immunofluorescence, ELISA, qPCR, and Western blot. Protein expression was detected by Western blot, and immunoprecipitation was used to confirm the interaction between Ub and CXCR4 (CXC chemokine receptor type 4).Results: Ub and CXCR4 were significantly upregulated in HCC tissues, and a positive correlation existed between them. In vitro, the migration of hepatoma cells was not affected by eUb directly, but their metastatic abilities were enhanced after coculture with the macrophages pretreated with eUb. Meanwhile, eUb promoted hepatoma cell metastasis in the lung in vivo and increased the ratio of M2 macrophages in the lung tissues and peripheral blood of tumor-bearing mice. Furthermore, the eUb-induced M2 macrophage polarization was related to the activation of the CXCR4/ERK (extracellular regulated protein kinase) signaling pathway.Conclusions: Extracellular ubiquitin promoted hepatoma metastasis through M2 macrophage polarization via the activation of the CXCR4/ERK signaling pathway, indicating that a personalized transfusion strategy is needed for the treatment of HCC patients. Neutralizing Ub in stored RBC units could lessen the detrimental clinical outcomes induced by the transfusion of stored RBCs.

RETRACTED ARTICLE: Exosomal DLX6-AS1 from hepatocellular carcinoma cells induces M2 macrophage polarization to promote migration and invasion in hepatocellular carcinoma through microRNA-15a-5p/CXCL17 axis

“…M2 macrophages are multifunctional to incur HCC cell migration and metastasis [ 42 ]. Exactly, extracellular ubiquitin-induced M2 macrophage polarization has been known to provoke lung metastasis of HCC cells [ 43 ]. Also, tumor cells-derived Wnt ligands-stimulated M2 macrophage polarization acts as an indirect actor for the migration and metastasis of HCC cells [ 44 ].…”

Resveratrol inhibited the metastatic behaviors of cisplatin‐resistant human oral cancer cells via phosphorylation of ERK/p‐38 and suppression of MMP‐2/9

“…In addition to the suppression of MMP‐2 and MMP‐9, 50 μM of resveratrol was found to inhibit the phosphorylation of ERK and p38 (Figure 5a), thus blocking the activation of these two proteins. The activation of ERK had been reported to promote the metastasis capacity of cancer cells (Cai et al., 2020; Lv et al., 2020; Meng et al., 2020; Song et al., 2020; Sun et al., 2020) and p38 (Hong et al., 2020; Liu et al., 2019; Pan et al., 2020; Ramadoss et al., 2017; Zhang et al., 2020; Zhu et al., 2019). In addition, blocking the phosphorylation of ERK and p38 has been tested as an anti‐metastatic strategy in cancer treatment (Choi et al., 2019; Tang et al., 2018).…”

Mesenchymal stem cells transfected with anti-miRNA-204-3p inhibit acute rejection after heart transplantation by targeting C-X-C motif chemokine receptor 4 (CXCR4) in vitro

“…Additionally, overexpression of CXCR4 by tumor cells has been shown to enhance polarization of macrophages toward the M2 phenotype (tumor associated macrophage TAM), which in turn enhance the proliferation and metastasis of malignant cells (20,39). However, until now, it had remained unclear whether expression of CXCR4 by MSCs induces macrophages toward the M2 phenotype.…”

“…Moreover, overexpression of CXCR4 on the surfaces of MSCs has demonstrated therapeutic potential in cardiovascular diseases (19). Additionally, surface expression of CXCR4 on tumor cells reportedly boosts macrophage polarization to the M2 phenotype within the tumor microenvironment, ultimately aggravating tumor progression (20). However, it has not yet been reported whether surface expression of CXCR4 by MSCs similarly influences macrophage polarization.…”