ADAM17-regulated CX3CL1 expression produced by bone marrow endothelial cells promotes spinal metastasis from hepatocellular carcinoma
INTERNATIONAL JOURNAL OF ONCOLOGY
Authors: Sun, Chi; Hu, Annan; Wang, Shengxing; Tian, Bo; Jiang, Libo; Liang, Yun; Wang, Houlei; Dong, Jian
Abstract
Spinal metastasis occurs in 50-75% of bone metastases caused by hepatocellular carcinoma (HCC), and HCC-derived spinal metastasis can lead to a less favorable prognosis. Recently, several studies have demonstrated that C-X3-C motif chemokine ligand 1 (CX3CL1) is closely associated with cancer metastasis, and its secretion is modulated by a disintegrin and metalloproteinase 17 (ADAM17). Bone marrow endothelial cells (BMECs) are an essential component of bone marrow. However, little is known about the roles in and effects of BMECs on HCC spinal metastasis. The present study demonstrated that CX3CL1 and C-X-C motif chemokine receptor 3 (CXCR3) expression was upregulated in HCC spinal metastases, and that CX3CL1 promoted the migration and invasion of HCC cells to the spine. Western blot analysis revealed that the Src/protein tyrosine kinase 2 (PTK2) axis participated in CX3CL1-induced HCC cell invasion and migration. CX3CL1 also increased the expression of M2 macrophage markers in THP-1 monocytes. BMECs promoted the migration and invasion of Hep3B and MHCC97H cells by secreting soluble CX3CL1, whereas the neutralization of CX3CL1 inhibited this enhancement. CX3CL1 enhanced the activation of the phosphatidylinositol-4,5-bisphos-phate 3-kinase catalytic subunit alpha (PIK3CA)/AKT serine/threonine kinase 1 (AKT1) and Ras homolog family member A (RHOA)/Rho associated coiled-coil containing protein kinase 2 (ROCK2) signaling pathways through the Src/PTK2 signaling pathway. Furthermore, ADAM17 was activated by mitogen-activated protein kinase (MAPK) z14 in BMECs and significantly promoted the secretion of CX3CL1. HCC cells enhanced the recruitment and proliferation of BMECs. The overexpression of CX3CR1 facilitated the spinal metastasis of HCC in a mouse modelin vivo. In addition,in vivoexperiments revealed that BMECs promoted the growth of HCC in the spine. The present study demonstrated that CX3CL1 participates in HCC spinal metastasis, and that BMECs play an important role in the regulation of CX3CL1 in the spinal metastatic environment.
Targeting Jak/Stat pathway as a therapeutic strategy against SP/CD44+tumorigenic cells in Akt/beta-catenin-driven hepatocellular carcinoma
JOURNAL OF HEPATOLOGY
Authors: Toh, Tan Boon; Lim, Jhin Jieh; Hooi, Lissa; Rashid, Masturah Bte Mohd Abdul; Chow, Edward Kai-Hua
Abstract
Background & Aims: Hepatic resection and liver transplantation with adjuvant chemo- and radiotherapy are the mainstay of hepatocellular carcinoma (HCC) treatment, but the 5-year survival rate remains poor because of frequent recurrence and intrahepatic metastasis. Only sorafenib and lenvatinib are currently approved for the first-line treatment of advanced, unresected HCC, but they yield modest survival benefits. Thus, there is a need to identify new therapeutic targets to improve current HCC treatment modalities. Methods: The HCC tumor model was generated by hydrodynamic transfection of AKT1 and beta-catenin (CTNNBI) oncogenes. Cancer cells with stemness properties were characterized following isolation using side population (SP) and CD44 surface markers by flow cytometry. The effect of Jak/Stat inhibitors was analyzed in vitro by using tumorsphere culture and in vivo using an allograft mouse model. Results: Co-activation of both Wnt/beta-catenin and Akt/mTOR pathways was found in 14.4% of our HCC patient cohort. More importantly, these patients showed poorer survival than those with either Wnt/beta-catenin or Akt/mTOR pathway activation alone, demonstrating the clinical relevance of our study. In addition, we observed that Akt/beta-catenin tumors contained a subpopulation of cells with stem/progenitor-like characteristics identified through SP analysis and expression of the cancer stem cell-like marker CD44, which may contribute to tumor self-renewal and drug resistance. Consequently, we identified small molecule inhibitors of the Jak/Stat pathway that demonstrated efficacy in mitigating tumor proliferation and formation in Akt/beta-catenin-driven HCC. Conclusions: In conclusion, we have shown that Akt/beta-catenin tumors contain a subpopulation of tumor-initiating cells with stem/progenitor-like characteristics which can be effectively targeted with inhibitors of the Jak/Stat pathway, demonstrating that inhibition of the Jak/Stat pathway could be an alternative method to overcome drug resistance and effectively treat Akt/beta-catenin-driven HCC tumors. Lay summary: The prognosis for patients with hepatocellular carcinoma is poor, partly because of the lack of effective treatment options for those with more advanced disease. In this study, we identified a subpopulation of cancer cells with stem cell-like properties that were critical for tumor maintenance and growth in a mouse model of hepatocellular carcinoma. Through further experiments, we demonstrated that the Jak/Stat pathway is a promising therapeutic target in hepatocellular carcinoma. (C) 2019 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.