Preclinical Assessment of the Potential Prognostic and Therapeutic Values of Hippo Signaling Cascade in Targeting Therapy-Resistant Cancer Stem Cells in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is an aggressive malignancy with approximately half a million cases diagnosed each year and it ranks as one of the most prevalent and lethal cancer types due to its high prevalence of metastasis and resistance to therapeutic interventions. The emerging cancer stem cell (CSC) theory entails that a subpopulation of cancer cells which are endowed with stem cell properties, including self-renewal, drug-resistant and metastatic, may be the underlying reason for treatment failure and disease recurrence. The Hippo-signaling cascade which is essential for the development of liver tissue has been shown to be aberrantly elevated in liver cancer cells. However the correlation between Hippo signaling and the generation of liver CSCs has not been fully appreciated. In this proposal, we intend to investigate the role of Hippo-signaling components such as Yes-associated protein (YAP) and its downstream effectors in the generation/maintenance of liver CSCs. We have established a flowcytometry-based method (side-population, SP) of identifying and isolating HCC cells which exhibit enhanced metastatic potential and resistance against chemotherapeutic agent cisplatin. Additionally, the expression level of YAP is found significantly higher in Mahlavu and SK-Hep1 SP cells. Based on these premises, we hypothesize that YAP and its components could be involved in the generation of CSCs and contributing to HCC malignancy. The following specific aims are proposed to our hypothesis. Aim1: Isolate and characterize HCC CSCs from both human HCC cell lines and patient derived samples. Aim2: Determine the role of Hippo-signaling in the generation/maintenance of HCC CSCs and their contribution to HCC malignancy. Aim3: In vivo validate the role of Hippo-signaling cascade in liver tumorigenesis and establish clinical correlation for prognostic value and therapeutic development. The findings of this study will provide essential preclinical data for treating HCC patients and the development of more effective therapeutic agents.