3417

IDH1

isocitrate dehydrogenase 1 (NADP+), soluble;IDH1;isocitrate dehydrogenase 1 (NADP+), soluble

NADP(+)-specific ICDH|NADP-dependent isocitrate dehydrogenase, cytosolic|NADP-dependent isocitrate dehydrogenase, peroxisomal|epididymis luminal protein 216|epididymis secretory protein Li 26|isocitrate dehydrogenase [NADP] cytoplasmic|oxalosuccinate deca

2q33.3

protein-coding

Comparative proteome analysis was performed between RT4 (grade-1) and T24 (grade-3) bladder cancer cell lines, in an attempt to identify differentially expressed proteins during bladder cancer progression. Among those relatively abundant proteins, seven spots changed more than two-fold reproducibly and identified by peptide mass fingerprinting using mass spectrometry and database search. We found most extensive and reproducible down-regulation of NADP dependent isocitrate dehydrogenase cytoplasmic (IDPc) and peroxiredoxin-II (Prx-II), in poorly differentiated T24 compared to well-differentiated RT4 bladder cancer cell line. Subsequent Western blotting analysis of human biopsy samples from bladder cancer patient revealed significant loss of IDPc and Prx-II in more advance tumor samples, in agreement with data on cell lines. These results suggest that loss of IDPc and Prx-II during tumor development may involve in tumor progression and metastasis. However, additional investigations are needed on large number of human samples to further verify these findings.

Melanoma is the most deadly tumor of the skin, and systemic therapies for the advanced stage are still limited. Recent genetic analyses have revealed the molecular diversity of melanoma and potential therapeutic targets. By screening a cohort of 142 primary nonepithelial tumors, we discovered that about 10% of melanoma cases (4/39) harbored an IDH1 or IDH2 mutation. These mutations were found to coexist with BRAF or KIT mutation, and all IDH1 mutations were detected in metastatic lesions. BRAF-mutated melanoma cells, additionally expressing the cancer-related IDH1 mutant, acquired increased colony-forming and in vivo growth activities and showed enhanced activation of the MAPK and STAT3 pathways. Genome-wide gene expression profiling demonstrated that mutant IDH1 affected the expression of a set of genes. Especially, it caused the induction of growth-related transcriptional regulators (Jun, N-myc, Atf3) and the reduction of Rassf1 and two dehydrogenase genes (Dhrs1 and Adh5), which may be involved in the carcinogenesis of IDH1-mutated tumors. Our analyses demonstrate that IDH1 mutation works with other oncogenic mutations and could contribute to the metastasis in melanoma.

Very few studies have been reported the function of wild type IDH1 in tumor progress. Previously, we reported that IDH1 correlated with pathological grade and metastatic potential inversely in human osteosarcoma. Here, IDH1 was found lower expressed in osteosarcoma tissues than that of adjacent normal bone tissues. In addition, we observed in vitro anti-proliferation and pro-apoptosis effects of up-regulated IDH1 on osteosarcoma cell lines. The migration and invasion activity was also markedly reduced by IDH1 up-regulation. Unexpectedly, IDH1 up-regulation also suppressed tumor growth and metastasis in vivo. Therefore, IDH1 may represent a potential novel treatment and preventive strategy for osteosarcoma.