Identification and Characterization of Tumorigenic Liver Cancer Stem/Progenitor Cells

doi:10.1053/j.gastro.2007.04.025

Gastroenterology

Volume 132, Issue 7, June 2007, Pages 2542-2556

https://doi.org/10.1053/j.gastro.2007.04.025 Get rights and content

Background & Aims: Recent efforts in stem cell biology suggest that tumors are organized in a hierarchy of heterogeneous cell populations and that the capability to maintain tumor formation/growth specifically resides in a small population of cells called cancer stem cells (CSCs). The aim of this study is to identify, isolate, and characterize the CSC population that drives and maintains hepatocellular carcinoma (HCC) growth and metastasis. Methods: Normal stem cells involved in liver regeneration were identified using a severe partial hepatectomy model. Purified HCC cells, with or without expression of the identified normal stem cell phenotype, were evaluated, based on their tumorigenic potential and exhibition of defined stem/progenitor cell-like properties, to determine whether liver CSCs can be or partly be identified by this surface marker. Results: We report the identification and isolation of a population of CSCs expressing a CD133 surface phenotype from human liver cell lines. CD133⁺ cells possess a greater colony-forming efficiency, higher proliferative output, and greater ability to form tumor in vivo. These cells are endowed with characteristics similar to those of progenitor cells including the expression of “stemness” genes, the ability to self-renew, and the ability to differentiate into nonhepatocyte-like lineages. Furthermore, CD133 is found to represent only a minority of the tumor cell population in human HCC specimens. Conclusions: We report the identification of a CSC population in HCC characterized by their CD133 phenotype. The identification of tumorigenic liver CSCs could provide new insight into the HCC tumorigenic process and possibly bear great therapeutic implications.

Section snippets

Animals

The study protocol was approved by and performed in accordance with the Committee of the Use of Live Animals in Teaching and Research at the University of Hong Kong. Nude or SCID mice aged between 4 and 8 weeks were used for partial hepatectomy (PH) experiments and to test the tumorigenicity potential of sorted cells from liver cell lines.

Mouse PH

For liver regeneration studies, nude mice were anesthetized and subjected to PH operations with a 70% liver resection. Animals were killed at days 0, 3, and 7

CD133⁺ Cells Are Increased in Regenerated Liver

To determine what normal stem cell markers are involved in liver regeneration, severe PH was performed on mice, and liver was harvested at time point day 0 (control), day 3 (early liver regeneration), and day 7 (late liver regeneration) followed by messenger RNA (mRNA) expression profile comparison using a cDNA microarray containing 34,000 genes (data not shown, unpublished data). Prominin-1, the mouse structural homologue of human CD133, was found to be up-regulated 93-fold in day 3 compared

Discussion

Stem cells are believed to sit at the top of the developmental hierarchy, possessing the unique ability to self-renew and to generate mature cells of all lineages through differentiation. They have the highest potential for proliferation and possess a longer life span compared with their progeny.¹⁹ It has been suggested that stem cells have 2 unique properties that make them likely to be involved in cancer development. First, they are often the only long-lived cells in a tissue that have the

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: Supported by Research Fund for the Control of Infectious Diseases (02040162), Research Grant Council (HKU 7393/04M), and Research Grant Council Central Allocation (HKU 1/06C).

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Basic–liver, pancreas, and biliary tractIdentification and Characterization of Tumorigenic Liver Cancer Stem/Progenitor Cells

Section snippets

Animals

Mouse PH

CD133+ Cells Are Increased in Regenerated Liver

Discussion

Lancet

Cell

Cancer Genet Cytogenet

Cell

J Hepatol

Differentiation

Arch Biochem Biophys

Molecular pathogenesis of human hepatocellular carcinoma

Nat Genet

Creation of human tumor cells with defined genetic elements

Nature

Rules for making human tumor cells

New Engl J Med

A cell initiating human acute myeloid leukaemia after transplantation into SCID mice

Nature

Human acute myeloid leukemia is organized as a hierarchy that originates from a primitive hematopoietic cell

Nat Med

Isolation and in vitro propagation of tumorigenic breast cancer cells with stem/progenitor cell properties

Cancer Res

Prospective identification of tumorigenic breast cancer cells

Proc Natl Acad Sci U S A

Identification of a cancer stem cell in human brain tumors

Cancer Res

Identification of human brain tumor initiating cells

Nature

Cancerous stem cells can arise from pediatric brain tumors

Proc Natl Acad Sci U S A

Highly purified CD44+ prostate cancer cells from xenograft human tumors are enriched in tumorigenic and metastatic progenitor cells

Oncogene

Prospective identification of tumorigenic prostate cancer stem cells

Cancer Res

CD133, a novel marker for human prostatic epithelial stem cells

J Cell Sci

Gastric cancer originating from bone marrow-derived cells

Science

A human colon cancer cell capable of initiating tumor growth in immunodeficient mice

Nature

Basic–liver, pancreas, and biliary tract
Identification and Characterization of Tumorigenic Liver Cancer Stem/Progenitor Cells

CD133⁺ Cells Are Increased in Regenerated Liver

Highly purified CD44⁺ prostate cancer cells from xenograft human tumors are enriched in tumorigenic and metastatic progenitor cells