Affiliations: [a] Liaoning Laboratory of Cancer Genetics and Epigenetics, Department of Cell Biology, Dalian Medical University, Dalian, Liaoning, China | [b] Department of Internal Dermatology, Dalian Dermatology Hospital, Dalian, Liaoning, China | [c] School of Life Science and Biotechnology, Faculty of Chemical, Environmental and Biological Science and Technology, Dalian University of Technology, Dalian, Liaoning, China
Correspondence:
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Corresponding author: Jia Liu, Liaoning Laboratory of Cancer Genetics and Epigenetics; Department of Cell Biology, Dalian Medical University, Dalian 116044, Liaoning, China. Tel.: +86 411 86110318; Fax: +86 411 86110278; E-mail: [email protected].
Note: [1]
These two authors contributed equally to this work.
Abstract: Background:S100A4 promotes cancer metastasis but is frequently silenced in human cutaneous squamous cell carcinomas/c-SCCs due to DNA methylation, which may explain the less metastasized property of c-SCCs. Objective:This study aims to check 1) whether the metastatic potential of S100A4-negative human c-SCC cells could be enhanced when S100A4 expression is restored in COLO16 c-SCC cells with S100A4 methylation and 2) the correlation of S100A4 expression and the differentiation grades and invasiveness of human c-SCC tumors. Methods:The motility and invasion of parent and transfected COLO16 cells are examined by the use of 24-well modified Boyden chambers, scratched wound healing assay and nude mouse transplantation tumor model. Meanwhile, the correlation of S100A4 expression with growth patterns and grade of differentiation of c-SCC surgical specimens are analyzed. Results:S100A4 expression is successfully restored in COLO16 cells after plasmid lipofectamine transfection. Transwell and scratched wound healing assays shows that the invasion and migration activities of S100A4-expressing transfectants are higher than that of parent COLO16 cells. Subcutaneous and foot pad c-SCC models are established by injecting 5×106/100l parental and S100A4-expressing COLO16 cells to BALB/c-nu/nude mice, respectively. Histological examination confirms the differences of invasiveness between the parent cells and the transfectants. Regional lymph node metastases are found only in the mice bearing S100A4-expressing tumors. S100A4 expression levels and frequencies are significantly different (P< 0.001) between the well and the poorly differentiated c-SCCs and closely correlated with tumor invasion (P< 0.05). Conclusions:S100A4 confers invasive and metastatic potentials on human c-SCCs. The low incidence of metastasis of c-SCCs, especially the well differentiated ones, might be due to the infrequent S100A4 expression. S100A4 can be regarded as a negative prognostic biomarker or a metastasis-risk factor of human c-SCCs.
Keywords: S100A4, cutaneous squamous cancer cells, invasion, metastasis, gene transfection
