Lactate dehydrogenase-B is silenced by promoter hypermethylation in human prostate cancer

• Published in: Oncogene Vol. 25; no. 20; pp. 2953 - 2960
• Main Authors: Leiblich, A, Cross, S S, Catto, J W F, Phillips, J T, Leung, H Y, Hamdy, F C, Rehman, I
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11.05.2006; Nature Publishing; Nature Publishing Group
• Subjects: Amino Acid Sequence; Apoptosis; Azacitidine - analogs & derivatives; Azacitidine - pharmacology; Azacytidine; Base Sequence; Biological and medical sciences; Bone cancer; Bone Neoplasms - genetics; Bone Neoplasms - secondary; Cell Biology; Cell physiology; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; Decitabine; Dehydrogenases; DNA Methylation; DNA Modification Methylases - antagonists & inhibitors; DNA sequencing; DNA, Neoplasm - genetics; Electrophoresis, Gel, Two-Dimensional; Enzymatic activity; Enzyme Inhibitors - pharmacology; Enzyme kinetics; Fundamental and applied biological sciences. Psychology; Gel electrophoresis; Gene expression; Gene Expression Regulation, Neoplastic; Gene Silencing; Human Genetics; Human subjects; Humans; Immunohistochemistry; Internal Medicine; Isoenzymes - deficiency; Isoenzymes - genetics; L-Lactate dehydrogenase; L-Lactate Dehydrogenase - deficiency; L-Lactate Dehydrogenase - genetics; Lactic acid; Male; Mass spectroscopy; Medical sciences; Medicine; Medicine & Public Health; Metastases; Metastasis; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Molecular weight; Nephrology. Urinary tract diseases; oncogenomics; Oncology; Promoter Regions, Genetic - genetics; Prostate cancer; Prostatic Neoplasms - genetics; Prostatic Neoplasms - pathology; Proteomics; Transcription. Transcription factor. Splicing. Rna processing; Tumor Cells, Cultured - drug effects; Tumor Cells, Cultured - metabolism; Tumors of the urinary system; Urinary tract. Prostate gland; proteomic; prostate cancer; metastatic; benign prostatic hyperplasia; hypermethylation; Human; Urinary system disease; Prostate disease; Enzyme; Transcription promoter; Malignant tumor; Metastasis; Carcinogenesis; L-Lactate dehydrogenase; Benign prostatic hyperplasia; Oxidoreductases; Benign neoplasm; Methylation; Male genital diseases; Prostate cancer
• ISSN: 0950-9232; 1476-5594
• DOI: 10.1038/sj.onc.1209262

In order to identify novel candidates associated with prostate cancer metastasis, we compared the proteomic profile of the poorly metastatic human prostate cancer cell line LNCaP, with its highly metastatic variant LNCaP-LN3, by two-dimensional gel electrophoresis. A major protein spot (pI of 5.9 and molecular weight of 37 kDa) was seen in LNCaP cells, but not in LNCaP-LN3 cells and was identified as lactate dehydrogenase-B (LDHB), by tandem mass spectrometry. Furthermore, enzyme kinetic assays and zymography showed a higher LDH enzyme activity in LNCaP cells compared with LNCaP-LN3. Bisulphite-modified DNA sequencing showed promoter hypermethylation in LNCaP-LN3 cells but not in LNCaP, Du145, PC3, CWR22 or BPH45 cells. Treatment of LNCaP-LN3 cells with 5′-azacytidine caused re-expression of LDHB transcripts. In tissues, LDHB promoter hypermethylation occurred at a higher frequency in prostate cancer, 14/ 31 (45%), compared to adjacent nonmalignant or benign tissue, 2/19 (11%) ( P <0.025). Immunohistochemistry showed a higher frequency of LDHB expression in benign or non-malignant tissues, 59/ 73 (81%), compared to cancer cases, 3/53 (6%) ( P <0.001). Absent LDHB expression was also seen in 7/7 (100%) cases of metastatic cancer in bone. Our data are the first to show loss of LDHB expression in prostate cancer, the mechanism of which appears to involve promoter hypermethylation.