Establishment and characterization of a novel human colorectal cancer cell line (CLY) metastasizing spontaneously to the liver in nude mice

Abstract

Colorectal cancer (CRC) with liver metastasis is a fatal disease with rapid progression and poor patient outcome. However, the molecular mechanism involved in liver metastasis of CRC remains essentially unknown, largely because of the presence of few available CRC cell lines with liver metastasis origin and spontaneous metastatic potentials in nude mice. In this study, we established a novel metastatic CRC cell line, CLY, derived from liver metastasis of a 64-year-old Chinese CRC patient. The cell line was characterized by morphology, growth kinetics, tumorigenicity, spontaneous liver metastatic potential, and cytogenetics. Immunofluorescence analysis of beta-catenin and E-cadherin and methylation-specific PCR (MSP) of the E-cadherin gene (CDH1) promoter were also used to compare CLY with conventional CRC cell lines (HT-29 and Lovo). CLY exhibited compact and polygonal-shaped epithelial cells in vitro and its population doubling time was 29.5 h. Subcutaneous transplantation of CLY into nude mice resulted in subcutaneous tumor formation and spontaneous liver metastasis in all of 10 nude mice. Cytogenetic analysis identified aneuploidy karyotypes with a modal chromosome number of 60. In immunofluorescence analysis, CLY exhibited a low expression but high restricted nuclear localization of beta-catenin and a silenced expression of E-cadherin, which may be induced by hypermethylation of the E-cadherin gene (CDH1) promoter and differed from conventional CRC cell lines. Therefore, CLY is an ideal cell model for further exploring the metastatic mechanisms of CRC and testing new therapeutic reagents for CRC with liver metastasis.