Screening candidate metastasis-associated genes in three-dimensional HCC spheroids with different metastasis potential.

purposePreviously, we have established a tissue-like HCC spheroid which better mirrors the biological features of tumorigenesis and metastasis. This study was to find out metastasis-associated genes between two 3D HCC spheroids with different metastasis potential using comparative PCR arrays. MATERIALS AND

methodsTwo HCC spheroids derived from high-metastatic MHCC97H cells and low-metastatic Hep3B cells were formed respectively in a rotating wall vessel bioreactor after 3D culture for 15 days. The candidate metastasis-associated genes related to cell adhesion, matrix secretion and invasion in HCC spheroids were screened by RT² profiler PCR arrays. The expression patterns of several differentially-expressed genes were further confirmed by real-time RT-PCR.

resultsTotal of 123 differential expression genes (fold-change>2) were found between two HCC spheroids, including 70 up-regulated genes (VCAM-1, IL-1β, CD44, tenascin C, SPP1, fibronectin, MMP-2, MMP-7, etc) and 53 down-regulated genes (E-cadherin, CTNND2, etc) in the high-metastatic spheroid. Function classification showed that the number of up-regulated genes related to adhesion molecules mediating cell-matrix interactions and matrix secretion was significantly higher in high-metastatic spheroid than that in low-metastatic spheroid. In contrast, the expressions of adhesion molecules maintaining homotypic tumor cell adhesion were decreased in metastatic spheroid as compared with that in low-metastatic spheroid. In addition, the expression pattern of seven selected genes associated with tumor metastasis measured by real-time RT-PCR were consistent with results of PCR arrays.

conclusionsObvious differences between two HCC spheroids in gene expression patterns of adhesion molecules, matrix secretion, invasion and other molecules may determine the different metastatic characteristics and malignant phenotype of HCC spheroid.