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Identification and Functional Validation of Thymosin Beta4 as a New Tumor Progression Biomarker for Oral Cancer by Tissue MALDI‐Imaging Mass Spectrometry
Author(s) -
Lai Tsungching,
Jan YiHua,
Chang JengShou,
Chiu Tony,
Hsiao Michael
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.354.4
Subject(s) - thymosin , cancer , immunohistochemistry , biomarker , gene knockdown , cancer research , metastasis , medicine , pathology , biology , biochemistry , gene
Oral cancer is the sixth lethal cancer in Taiwan. It mainly occurs in Central and Southeast Asia. Here we used MALDI‐imaging MS and LC MS/MS for the identification of new oral cancer biomarkers. Protein lysates of normal keratinocyte and oral cancer cell lines were subjected to 1D SDS‐PAGE‐based LC‐MS/MS analysis. All proteins were estimated by comparison with software, Scaffold. We also used MALDI‐imaging MS to analyze different clinical stage patient samples. Candidate proteins, recognized by FlexImage software, were compared with the databases from LC MS/MS. Furthermore, we validated candidate proteins by quantitative PCR and immunohistochemistry. Our results of MALDI imaging analysis showed the expression of Thymosin β4 correlated with malignant progression of the oral cancers. The protein expression of Thymosin β4 in oral clinical N/T paired tissue array was determined by immunohistochemistry analysis and showed that Thymosin β4 overexpression was found mainly in malignant stage of oral cancer samples and significantly associated with poor clinical outcome. In addition, mRNA level of Thymosin β4 showed similar trends in different stages of N/T paired oral cancer samples by real‐time semi‐quantitative PCR. Knockdown of Thymosin β4 expression by shRNA inhibited the invasive ability in oral cancer cell lines. In conclusions, we have identified a 5 kDa protein, Thymosin beta4, by MALDI‐Imaging MS analysis. Overexpression of Thymosin beta4 was found to be associated with oral cancer progression. The possible mechanisms were explored.