The regulatory mechanisms and inhibitors of isocitrate dehydrogenase 1 in cancer

Reprogramming of energy metabolism is one of the basic characteristics of cancer and has been proved to be an important cancer treatment strategy. Isocitrate dehydrogenases (IDHs) are a class of key proteins in energy metabolism, including IDH1, IDH2, and IDH3, which are involved in the oxidative decarboxylation of isocitrate to yield α-ketoglutarate (α-KG). Mutants of IDH1 or IDH2 can produce d-2-hydroxyglutarate (D-2HG) with α-KG as the substrate, and then mediate the occurrence and development of cancer. At present, no IDH3 mutation has been reported. The results of pan-cancer research showed that IDH1 has a higher mutation frequency and involves more cancer types than IDH2, implying IDH1 as a promising anti-cancer target. Therefore, in this review, we summarized the regulatory mechanisms of IDH1 on cancer from four aspects: metabolic reprogramming, epigenetics, immune microenvironment, and phenotypic changes, which will provide guidance for the understanding of IDH1 and exploring leading-edge targeted treatment strategies. In addition, we also reviewed available IDH1 inhibitors so far. The detailed clinical trial results and diverse structures of preclinical candidates illustrated here will provide a deep insight into the research for the treatment of IDH1-related cancers.

Preclinical efficacy against acute myeloid leukaemia of SH1573, a novel mutant IDH2 inhibitor approved for clinical trials in China

Acute myeloid leukaemia (AML) is the most common form of acute leukaemia in adults, with increasing incidence with age and a generally poor prognosis. Almost 20% of AML patients express mutant isocitrate dehydrogenase 2 (mIDH2), which leads to the accumulation of the carcinogenic metabolite 2-hydroxyglutarate (2-HG), resulting in poor prognosis. Thus, global institutions have been working to develop mIDH2 inhibitors. SH1573 is a novel mIDH2 inhibitor that we independently designed and synthesised. We have conducted a comprehensive study on its pharmacodynamics, pharmacokinetics and safety. First, SH1573 exhibited a strong selective inhibition of mIDH2 R140Q protein, which could effectively reduce the production of 2-HG in cell lines, serum and tumors of an animal model. It could also promote the differentiation of mutant AML cell lines and granulocytes in PDX models. Then, it was confirmed that SH1573 possessed characteristics of high bioavailability, good metabolic stability and wide tissue distribution. Finally, toxicological data showed that SH1573 had no effects on the respiratory system, cardiovascular system and nervous system, and was genetically safe. This research successfully promoted the approval of SH1573 for clinical trials (CTR20200247). All experiments demonstrated that, as a potential drug against mIDH2 R140Q acute myeloid leukaemia, SH1573 was effective and safe.

Oncometabolite 2-HG in glioma evolution and recent progress of detection method / 中国药理学通报

IDH mutation is prevalent in lower-grade glioma and secondary glioblastoma. Patients bearing IDH mutation are char-acterized by overproduction of 2-HG. 2-HG plays a role in regu-lation of DNA and histone hypermethylation in glioma, thus re-sulting in impaired cell differentiation and tumor formation. As a surrogate marker of mutant IDH, there is increasing interest in development of detection methods for 2-HG. LC-MS is widely used in detecting 2-HG in vitro, and reliable measurement of 2-HG by the non-invasive MRS has been tested in vivo and ex vivo previously. However, whether 2-HG could represent an inde-pendent predictor of patient survival or other clinical features for glioma still needs further study. In this review, we summarize the mechanism adopted by 2-HG in glioma initiation and pro-gression, as well as the detection method tested in clinic. We try to provide guidance to the future combination therapy using mu-tant IDH inhibitors.

Effect of IDH gene mutation on acute myeloid leukemia / 上海交通大学学报（医学版）

Isocitrate dehydrogenase (IDH) is an important metabolic enzyme involved in the tricarboxylic acid cycle. In recent years, IDH has become the most frequent tumor metabolic mutation gene in acute myeloid leukemia (AML). Unlike other mutations, it gains new functions which can catalyze α-ketoglutarate (α-KG) to produce the tumor metabolite D-2-hydroxyglutarate (D-2-HG). The increased D-2-HG in the cells can affect bone marrow cell differentiation and proliferation and induce myeloid tumors by the genetic controls, cell signaling, bone marrow microenvironment changes and other ways. Currently, the new IDH2 inhibitors AG-221 and IDH1 inhibitors become the first-line drugs targeted therapy in patients with IDH mutations in AML. This paper focused on the mutation of IDH and its mutation characteristics, the formation mechanism of AML by the metabolites produced by mutation, the metabolic pathway of tumor metabolites and the research progress of IDH inhibitors.

Isocitrate dehydrogenase gene mutations in intrahepatic cholangiocarcinoma / 中华肝胆外科杂志

Mutations in isocitrate dehydrogenase are among the most common genetic alterations in intrahepatic cholangiocarcinoma (ICC).Mutant IDH proteins in ICC and other malignancies acquire an abnormal enzymatic activity, allowing the conversion of alpha-ketoglutarate (alphaKG) to 2-hydroxyglutarate (2HG), which inhibits the activity of multiple alphaKG-dependent dioxygenases, and results in alterations in cell differentiation and tumorigenesis.This review will focus on recent advances, which may help understand the function of IDH mutation in intrahepatic cholangiocarcinoma.