Bioinformatics analysis and expression study of fumarate hydratase in lung cancer

Background: As its etiology and pathogenesis is obscure, illustrating the molecular mechanism of lung cancer has become a serious and urgent task. Studies have shown that fumarate hydratase (FH) is a tumor suppressor related to tumorigenesis, development, and invasion. Our aim was to analyze the biological information of FH, and detect the messenger ribonucleic acid (mRNA) and protein expression of FH in lung cancer cells to explore its role in tumorigenesis and in the development of lung cancer. Method: We analyzed the biological characteristics of FH, then utilized reverse transcription-polymerase chain reaction (RT-PCR) to study FH mRNA expression in A549 and 16 human bronchial epithelial (HBE) cell lines. The protein expression of FH was detected in 57 cases of human lung cancer tissues and 19 cases of normal lung tissues by immunohistochemistry. Results: 1. Bioinformatic analysis: FH mainly exist in the mitochondria; the common structural elements of FH are mainly α-helix, random coil, β-turn, and extended strand; there are five possible transmembrane domains in the entire polypeptide chain; FH is a hydrophilic and soluble protein. 2. RT-PCR result: FH mRNA expression was downregulated in A549 cells compared with 16HBE cells. 3. Immunohistochemistry: FH protein expression was significantly lower in lung cancer cells than in normal lung tissues (P < 0.05), but was not correlated with the patients' age, gender, tumor size, pathological type, or lymph node, distant, or tumor node metastasis stage. Conclusion: FH was under-expressed in lung cancer, suggesting that it may be an indicator of tumorigenesis and could be a potential target for therapies against lung cancer in the future.