Targeting Jak/Stat pathway as a therapeutic strategy against SP/CD44+ tumorigenic cells in Akt/β-catenin-driven hepatocellular carcinoma

• Published in: Journal of hepatology 2020-01, Vol.72 (1), p.104-118
• Main Authors: Toh, Tan Boon, Lim, Jhin Jieh, Hooi, Lissa, Rashid, Masturah Bte Mohd Abdul, Chow, Edward Kai-Hua
• Format: Article
• Language: English
• Subjects: Akt; AKT protein; AKT1 protein; Allografts; CD44; CD44 antigen; Cell culture; Cell self-renewal; Drug resistance; Flow cytometry; Hepatocellular carcinoma; Jak/Stat; Liver cancer; Liver transplantation; Medical prognosis; Metastases; Patients; Radiation therapy; Side population; Stem cells; Surface markers; Therapeutic applications; TOR protein; Transfection; Tumors; Wnt protein; β-Catenin
• ISSN: 0168-8278; 1600-0641
• DOI: 10.1016/j.jhep.2019.08.035

[Display omitted] •Co-activation of both Akt/mTOR and Wnt/ β-catenin signaling pathways was found in 14.4% of patients with HCC.•Co-activation of these pathways confers worse survival compared to Akt/mTOR or Wnt/β-catenin activation alone.•Akt/β-catenin tumors contained a subpopulation of cells with stem/progenitor-like characteristics.•MDR1 was the main driver of SP phenotype in the Akt/β-catenin-driven HCC.•Activated Stat3 regulates the self-renewing and tumorigenic population of SP/CD44+ cells in Akt/β-catenin tumors. 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. The HCC tumor model was generated by hydrodynamic transfection of AKT1 and β-catenin (CTNNB1) 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. Co-activation of both Wnt/β-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/β-catenin or Akt/mTOR pathway activation alone, demonstrating the clinical relevance of our study. In addition, we observed that Akt/β-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/β-catenin-driven HCC. In conclusion, we have shown that Akt/β-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 eff