Tong Tong

PURPOSE: Aurora-A/STK15/BTAK, a centrosome-associated oncogenic protein, is implicated in the control of mitosis. Overexpression of Aurora-A has been shown to result in chromosomal aberration and genomic instability. Multiple lines of evidence indicate that Aurora-A induces cell malignant transformation. In the current study, we are interested in investigating the expression of Aurora-A in human esophageal squamous cell carcinoma (ESCC) and characterizing the association of Aurora-A with ESCCmalignant progression. EXPERIMENTAL DESIGN: Aurora-A protein expression was examined in 84 ESCC tissues and 81 paired normal adjacent tissues by either immunohistochemistry or Western blot analysis. In addition, a gene-knockdown small interfering RNA technique was used in ESCC cells to investigate whether Aurora-A contributes to the ability of a tumor to grow invasively. RESULTS: The amount of Aurora-A protein in ESCC was considerably higher than that in normal adjacent tissues. Overexpression of Aurora-A was observed in 57 of 84 (67.5%) ESCC samples. In contrast, <2% of normal adjacent tissue displayed high expression of Aurora-A. Interestingly, overexpression of Aurora-A seemed to correlate with the invasive malignancy of ESCC. Disruption of endogenous Aurora-A using small interfering RNA technique substantially suppressed cell migrating ability. CONCLUSION: The findings presented in this report show that Aurora-A expression is elevated in human esophageal squamous cell carcinoma and is possibly associated with tumor invasion, indicating that overexpression of Aurora-A may contribute to ESCC occurrence and progression.

BACKGROUND: The development of esophageal squamous cell carcinoma (ESCC) progresses a multistage process, collectively known as precursor lesions, also called dysplasia (DYS) and carcinoma in situ (CIS), subsequent invasive lesions and final metastasis. In this study, we are interested in investigating the expression of a variety of functional classes of proteins in ESCC and its precursor lesions and characterizing the correlation of these proteins with ESCC malignant progression. METHODS: Fas, FADD, caspase 8, CDC25B, fascin, CK14, CK4, annexin I, laminin-5gamma2 and SPARC were analyzed using immunohistochemistry on tissue microarray containing 205 ESCC and 173 adjacent precursor lesions as well as corresponding normal mucosa. To confirm the immunohistochemical results, three proteins, fascin, CK14 and laminin-5gamma2, which were overexpressed in ESCC on tissue microarray, were detected in 12 ESCC cell lines by Western blot assay. RESULTS: In ESCC and its precursor lesions, FADD, CDC25B, fascin, CK14, laminin-5gamma2 and SPARC were overexpressed, while Fas, caspase 8, CK4 and annexin I were underexpressed. The abnormalities of these proteins could be classified into different groups in relation to the stages of ESCC development. They were "early" corresponding to mild and moderate DYS with overexpression of fascin, FADD and CDC25B and underexpression of Fas, caspase 8, CK4 and annexin I, "intermediate" to severe DYS and CIS with overexpression of FADD and CK14, and "late" to invasive lesions (ESCC) and to advanced pTNM stage ESCC lesions with overexpression of CK14, laminin-5gamma2 and SPARC. CONCLUSION: Analyzing the protein expression patterns of Fas, FADD, caspase 8, CDC25B, fascin, CK14, CK4, annexin I, laminin-5gamma2 and SPARC would be valuable to develop rational strategies for early detection of lesions at risk in advance as well as for prevention and treatment of ESCC.

S100 proteins have been implicated in tumorigenesis and metastasis. As a member of S100 proteins, the role of S100A14 in carcinogenesis has not been fully understood. Here, we showed that ectopic overexpression of S100A14 promotes motility and invasiveness of esophageal squamous cell carcinoma cells. We investigated the underlying mechanisms and found that the expression of matrix metalloproteinase (MMP)-2 is obviously increased after S100A14 gene overexpression. Inhibition of MMP2 by a specific MMP2 inhibitor at least partly reversed the invasive phenotype of cells overexpressing S100A14. By serendipity, we found that S100A14 could affect p53 transactivity and stability. Thus, we further investigated whether the effect of MMP2 by S100A14 is dependent on p53. A series of biochemical assays showed that S100A14 requires functional p53 to affect MMP2 transcription, and p53 potently transrepresses the expression of MMP2. Finally, RT-quantitative PCR analysis of human breast cancer specimens showed a significant correlation between S100A14 mRNA expression and MMP2 mRNA expression in cases with wild-type p53 but not in cases with mutant p53. Collectively, our data strongly suggest that S100A14 promotes cell motility and invasiveness by regulating the expression and function of MMP2 in a p53-dependent manner. S100 proteins have been implicated in tumorigenesis and metastasis. As a member of S100 proteins, the role of S100A14 in carcinogenesis has not been fully understood. Here, we showed that ectopic overexpression of S100A14 promotes motility and invasiveness of esophageal squamous cell carcinoma cells. We investigated the underlying mechanisms and found that the expression of matrix metalloproteinase (MMP)-2 is obviously increased after S100A14 gene overexpression. Inhibition of MMP2 by a specific MMP2 inhibitor at least partly reversed the invasive phenotype of cells overexpressing S100A14. By serendipity, we found that S100A14 could affect p53 transactivity and stability. Thus, we further investigated whether the effect of MMP2 by S100A14 is dependent on p53. A series of biochemical assays showed that S100A14 requires functional p53 to affect MMP2 transcription, and p53 potently transrepresses the expression of MMP2. Finally, RT-quantitative PCR analysis of human breast cancer specimens showed a significant correlation between S100A14 mRNA expression and MMP2 mRNA expression in cases with wild-type p53 but not in cases with mutant p53. Collectively, our data strongly suggest that S100A14 promotes cell motility and invasiveness by regulating the expression and function of MMP2 in a p53-dependent manner.