Date on Master's Thesis/Doctoral Dissertation

8-2015

Document Type

Master's Thesis

Degree Name

M.S.

Department

Pharmacology and Toxicology

Degree Program

Pharmacology and Toxicology, MS

Committee Chair

Martin II, Robert

Committee Co-Chair (if applicable)

Hein, David

Committee Member

Hein, David

Committee Member

Bhatnagar, Aruni

Committee Member

Bodduluri, Haribabu

Committee Member

Li, Yong

Subject

Liver--Cancer; Stem cells

Abstract

Hepatocellular Carcinoma (HCC) is a challenging condition to treat in the clinic due to its distinct tumor phenotype, aggressive growth, and chemotherapy resistance. Cancer Stem Cells (CSCs) are a poorly differentiated subpopulation of cells within the tumor microenvironment, and role of CSCs in tumor initiation and chemotherapy resistance is not well understood in HCC. In this study, we have successfully identified HCC cells with CSC-like properties that showed resistance to Doxorubicin. Using the established serum free culture techniques, we have enriched CSC-like cells among hepatocellular cancer cells. These enriched cells exhibit all CSC-like properties i.e. self-renewal capability, anchorage independent growth with retained proliferation property and resistance to Doxorubicin. We confirmed expression of CSC surface markers (EpCAM, CD90, CD44, CD133) and functional markers (ALDH activity and dye exclusion properties) in enriched HCC-CSCs. Preliminary in vivo data in our mouse models supports that spheroid forming CSCs show higher rate of tumor proliferation compared to untreated (non-spheroid forming) HCC cells. Wnt/β- catenin pathway components were also found to be overexpressed in CSCs when compared to non spheroids. Analysis of 24 paired human specimens from HCC tissues by IHC showed higher EpCAM expression, and Western Blot analysis suggested concomitant changes in β-catenin and EpCAM levels. In conclusion: (1) we have successfully induced and identified HCC cells with CSClike properties; (2) Aberrant β-catenin up-regulation mediated Wnt/β-catenin signaling activation was observed in enriched hepatoma spheroids.

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