Isocitrate Research Articles

A Rare Case of Systemic Mastocytosis With Associated Clonal Hematological Non-Mast Cell Lineage Disease That Transformed to Acute Leukemia With IDH2 Mutation

An elderly 72-year-old man presented with anemia, thrombocytopenia, monocytosis, splenomegaly and lymphadenopathy. Bone marrow biopsy was consistent with mast cell neoplasm with positive CD117, CD25, CD34 myeloblasts and polymerase chain reaction (PCR) revealed mutation of D816V. He developed bilateral femoral neck fractures and biopsy confirmed that he has systemic mastocytosis (SM). He received cladribine and midostaurin with stable disease for 21 months. His SM with associated clonal hematological non-mast cell lineage disease (SM-AHNMD) transformed to acute myelogenous leukemia with isocitrate dehydrogenase 2 ( IDH2 ) mutation. A trial of enasidenib was given for 5 months but without any response. Patient decided to go with home hospice and died afterwards. J Med Cases. 2020;11(10):317-319 doi: https://doi.org/10.14740/jmc3552

Pathological characteristics of recurrent glioma and its prognosis analysis

Objective To explore the pathological characteristics of recurrent glioma and its relationship with the patient′s prognosis. Methods A retrospective analysis was conducted on the clinical data of 54 patients with recurrent glioma treated at Neurosurgery Department, Sun Yat-sen University Cancer Center from August 2002 to December 2016. All patients underwent a second operation of tumor resection and postoperative pathological examinations including the World Health Organization (WHO) classification of the tumor, Ki-67 index, O6-methylguanine-DNA-methyltransferase (MGMT) status and isocitrate dehydrogenase 1 (IDH1) status. The histopathological features of recurrent samples were classified according to presence of necrosis and tumor cells as well as activity of tumor cells. The overall survival (OS) of patients was analyzed using the Kaplan-Meier method. The univariate and multivariate Cox regression analysis was further conducted to determine the clinical factors affecting OS in patients with recurrent glioma. Results Pathological test results in 54 patients were as follows: (1) In terms of WHO grade, there were 6 cases of grade Ⅱ(11.1%), 14 cases of grade Ⅲ(25.9%), 30 cases of grade Ⅳ(55.6%), and 4 cases (7.4%) without tumor cells. Compared with the first operation, there was no change in the WHO grade in 32 patients (59.2%), 7 (13.0%) had lower WHO tumor grades and 15 (27.8%) had higher grades; (2) In terms of Ki-67 index, out of 32 cases undergoing two times of testing, 15 cases had decreased Ki-67 index, 14 had increased Ki-67 index, and 3 cases had unchanged index; (3) In terms of IDH1 status, out of 29 cases undergoing two times of relevant tests, 9 cases were mutant and 20 were wild type; (4) In terms of MGMT status: out of 8 cases undergoing two times of relevant tests, 6 cases consisting of 3 cases with positive expression and 3 cases with negative expression had no change, and the remaining 2 changed from positive expression in the first test to negative expression in the second test; (5) In terms of pathological classification, 4 cases were necrosis type, 20 were mixed type, and 30 were active type. The follow-up time of 54 patients was 16.1±3.2 months (1.3-160.3 months). The Kaplan-Meier analysis showed a median OS of 14.4 months in 54 patients. The result of multivariate Cox regression analysis showed that high WHO grade of recurrence tumor (HR=2.80, 95% CI: 1.42-5.53, P<0.01) and absence of postoperative radiotherapy (HR=4.05, 95% CI: 1.41-11.64, P=0.01) were independent risk factors affecting OS in patients with recurrent glioma. Conclusions This preliminary study has suggested that recurrent gliomas might have changed pathological results revealed post re-surgery, and low WHO tumor grade and postoperative radiotherapy seem to be predictive factors of better prognosis. Key words: Glioma; Recurrence; Pathology; Prognosis

Expression and clinical significance of calumenin in brain gliomas

Objective To detect the expression of calumenin (CALU) in human brain glioma samples, to explore its effect on the patient′s outcome, and to analyze the related biological functions of the genes co-expressed with CALU. Methods A retrospective analysis was conducted on CALU sequencing expression and clinical data of 288 glioma patients with positive CALU expression in the mRNAseq_325 database of Chinese Glioma Genome Atlas (CGGA). We analyzed the effects of CALU expression levels on survival in different types of glioma patients. The multivariate Cox regression method was used to determine the relevant factors affecting the survival of glioma patients. Pearson correlation analysis was employed to screen the related genes co-expressed with CALU and their biological functions were explored using the online bioinformatic analysis tools. Results Among the 288 patients, the expression of CALU was 4.74±0.68, 5.49±1.12 and 6.17±0.94 in World Health Organization (WHO) grade Ⅱ, Ⅲ, and Ⅳ patients respectively, and 6.13±1.17 and 5.08±0.76 in isocitrate dehydrogenase l (IDH1) wild-type and IDH1 mutant gliomas respectively, and 5.79±0.07 and 4.71±0.07 in gliomas with 1p/19q non-codeletion and 1p/19q co-deletion. The comparative differences in the above indicators were statistically significant (all P 0.05). The median survival of CALU patients with high and low expression levels (144 cases in each) was 13.0(1-132)months and 82.5(2-149)months, respectively, which had statistically significant difference (P<0.01). In patients with WHO grade Ⅱ-Ⅳ gliomas, the high expression of CALU mainly reduced the survival time of grade Ⅲ and Ⅳ patients (both P<0.01). The multivariate Cox regression analysis showed that CALU expression was an independent factor influencing the survival of glioma patients (RR=2.193, 95%CI: 1.507-3.192, P<0.01). In the CGGA database, there were 325 genes that were positively correlated with CALU expression. The biological functions of those genes were mainly signal transduction, cell adhesion and cellular metabolism, and were mainly involved in endoplasmic reticulum protein processing, adhesion and cancer pathways. Conclusion CALU is significantly related to the malignancy of brain glioma and may serve as an independent prognostic factor in high grade glioma patients, which thus provides a potential therapeutic target in the future research. Key words: Glioma; Gene expression; Prognosis; Calumenin

Clinical characteristics and prognostic factors of insular glioblastomas

Objective To explore the clinical characteristics and prognostic factors of insular glioblastomas. Methods Clinical data of 44 patients with insular glioblastomas in Chinese Glioma Genome Atlas(CGGA) databases from July 2006 to June 2013 were evaluated. All patients underwent tumor resection. Among them, 27 underwent adjuvant radiochemotherapy and 17 underwent no postoperative adjuvant therapy. Progression-free survival (PFS) and overall survival (OS) of all patients were analyzed by Kaplan-Meier method. Furthermore, multivariate Cox regression analysis was used to investigate the prognostic clinical factors. Results In a total of 44 patients, 33 (75.0%) had a history of epileptic seizure, 11 (25.0%) had isocitrate dehydrogenase 1 (IDH1) mutation, 19 (43.2%) had O6-methy-lguanine-DNA-methyltransferase (MGMT) methylation, and 42 (95.5%) had tumor enhancement.Based on Yasargil′s classification, there were type 3A in 2 cases, type 3B in 27 cases and type 5A/B in 15 cases. Based on Saito′s classification, there were 2 cases confined to the insular cortex, 9 cases with invasion to the frontal lobe via the anterior circumferential sulcus, 16 cases with invasion to the temporal lobe via the lower circumferential sulcus, and 17 cases with invasion to multiple directions via more than 2 circumferential sulci. Based on Moshe′s classification, there were 35 cases with envelopment or invasion of the lenticulostriate artery, while no invasion was reported in the remaining 9 cases. Based on the putamen classification, there were 38 cases with various degrees of putamen invasion, and the remaining 6 cases had no involvement of the putamen. Kaplan-Meier curve showed that the median PFS of all patients was 278 d and the median OS was 435 d. Multivariate Cox regression analysis showed that tumor volume < median (HR = 0.390, 95% CI: 0.189-0.802, P=0.011), IDH1 mutation (HR=0.391, 95% CI: 0.175-0.876, P=0.023) and postoperative radiochemotherapy (HR=0.346, 95% CI: 0.162-0.738, P=0.006) were independent protective factors for PFS. However, MGMT methylation (HR=0.371, 95% CI: 0.181-0.758, P=0.007), tumor resection degree ≥90% (HR=0.412, 95% CI: 0.194-0.875, P=0.021) and postoperative radiochemotherapy (HR=0.347, 95% CI: 0.170-0.708, P=0.004) were independent protective factors for OS. Conclusions Clinical characteristics of insula glioblastomas include relatively lower incidence, stronger invasiveness, lower total resection ratio and poorer prognosis. Maximum resection and standard postoperative radiochemotherapy may lead to a better outcome. Key words: Glioblastoma; Insula; Prognosis; Multivariate analysis

Metabolic Status during Germination of Nano Silica Primed Zea mays Seeds under Salinity Stress

Priming is a safe, easy, and effective way to increase plant tolerance against stress. This research aims to study the metabolic status of the nano-silica-primed germinated maize seeds under salinity stress. We prepare the nano-silica solution (10 mg/ml) from rice straw. We primed group maize seeds with nano-silica solution and the other group remained dry. The two seeds group germinated under different concentrations of NaCl (0, 50, 150 mM). Nano-silica primed seeds showed a higher germination rate and seedling vigor index. Priming helps the maize seeds to germinate under salinity stress through increasing the antioxidant enzymes activity which in turn suppresses the increase in the reactive oxygen species and so decreases the lipid peroxidation. Also, priming increases the gibberellin content and therefore activates the amylase and lipase activities which ensured the availability of the simple compounds needed for energy releasing through respiration. Besides that, priming enhances the activity of the respiration enzymes such as aldolase and iso citrate lyase. Finally, nano-silica priming enhanced the metabolic status of maize seeds under salinity stress.

Withaferin A suppresses skin tumor promotion by inhibiting proteasome-dependent isocitrate dehydrogenase 1 degradation

Background: The metabolic enzyme isocitrate dehydrogenase 1 (IDH1) belonging to β-decarboxylase dehydrogenase family has been identified as a tumor suppressor. Withaferin A (WA), a bioactive compound derived from Withania somnifera , has the anti-tumor activity. Based on the data set that WA inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced IDH1 inactivation and mitochondrial dysfunction, we focused on how WA suppressed the skin carcinogenesis mediated by IDH1. Methods: The mRNA levels of IDH1 were measured after treated with TPA and/or WA. The expression of IDH1, lactate dehydrogenase (LDH) involved in glycolysis, hypoxia inducible factor-1α (HIF-1α) and its target gene glucose transporter-1 (Glut1) were detected. The activities of proteasome and the mitochondrial complex I related to mitochondrial functions were determined. The enzymatic activities of LDH, proline hydroxylase (PHD) and vascular endothelial growth factor (VEGF) were analyzed. Results: The qPCR data have shown the mRNA levels of IDH1 were no difference with TPA and/or WA treatment. Next, data demonstrated that WA could stabilize IDH1 by inhibiting the ubiquitin-proteasome pathway (UPP). Followed by illuminating the mechanism of IDH1 inhibiting tumorigenesis, the results mirrored that upregulated IDH1 suppressed LDH activity whereas increased mitochondrial complex I activity. Furthermore, via its product α-KG, upregulated IDH1 activated PHD, and inhibited HIF-1α and its downstream signaling pathway. Conclusions: Our results indicate that WA inhibits tumor promotion partially via stabilizing IDH1, leading to inactivating the HIF-1α signaling.

Prognostic values of preoperative albumin to globulin ratio for predicting clinical outcome in patients with high-grade gliomas

Background: Gliomas was the most common primary central nervous system tumors which have an increased morbidity in recent years. And the clinical prognosis of high-grade gliomas (HGG, WHO grade III to IV) was most with an average survival rate of only dozens of months. Many researchers concluded that the level of preoperative albumin-to-globulin ratio (AGR) could predict the clinical outcome of patients with solid malignant tumors. Methods: Two hundred and thirty-two cases of patients who were diagnosed HGG by pathology were enrolled in the study. The relevant data of the cohort included sex, age, preoperative Karnofsky performance score (KPS), extent of resection, albumin count and globulin count, isocitrate dehydrogenase (IDH) and survival time were collected. The survival rate was obtained by using the Kaplan-Meier method. The cut-off value of AGR was determined by X-tile software. Univariate survival analysis was performed by the log-rank method. Proportional hazards model (Cox model) was performed for multivariate analysis. Results: The optimal cut-off value of AGR was 1.32. Results showed that the preoperative AGR was correlated with clinical prognosis of patients with HGG, and the survival time of the patients with high AGR (AGR >1.32) was significantly longer. Moreover, the prognosis of patients with high AGR was better in IDH wild-type HGG. Conclusions: Preoperative AGR might predict the clinical prognosis of patients with HGG.

Analysis of risk factors influencing the progression-free survival in WHO II grade gliomas

Objective To investigate the risk factors that influence the progression-free survival (PFS) in WHO Ⅱ-grade gliomas in adults. Methods Clinical data obtained from 72 patients with WHO Ⅱ grade gliomas undergoing surgical resection between January 2008 and December 2015 at Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University were analyzed. Immunohistochemistry staining method was employed to detect mutation of isocitrate dehydrogenase 1(IDH1) R132H, α thalassemia/mental retardation syndrome X-linked(ATRX) and the expression of regulator of telomere elongation helicase 1(RTEL1). Survival analysis was estimated by Kaplan-Meier analysis. Cox regression modelling was used for univariate analysis and multivariate analysis. Results The results of immunohistochemical staining in 72 patients with gliomas revealed 39 (54.2%) cases of IDH1 R132H mutant positive, 33 (45.8%) cases of negative; 56 (77.8%) cases of ATRX missing mutant negative, 16 (22.2%) cases of positive; 29 (40.3%) cases of RTEL1 positive and 43 (59.7%) cases of negative. The results of survival analysis showed that the cumulative PFS rate of IDH1 R132H negative patients was lower than that of IDH1 R132H positive(P 0.05). The cumulative PFS rate of RTEL1 positive patients was lower than that of RTEL1 negative patients (P 40 years (OR=3.618, 95% CI: 1.688-7.753, P=0.001), partial resection (OR=0.204, 95% CI: 0.064-0.656, P=0.008), expression of IDH1 R132H negative (OR=2.867, 95% CI: 1.129-7.282, P=0.027) and RTEL1 positive (OR=0.354, 95% CI: 0.151-0.827, P=0.016) were independent factors influencing PFS of glioma patients, and could be independently used for prognostic judgment of glioma patients. Conclusion Age (>40 years), degree of tumor resection (partial resection), expression of IDH1 R132H (negative) and RTEL1 expression (positive) are independent risk factors affecting the PFS of WHO Ⅱ-grade gliomas. Key words: Glioma; Progression-free survival; Isocitrate dehydrogenase 1; α thalassemia/mental retardation syndrome X-linked; Telomere elongation helicase 1

Prognostic values of isocitrate dehydrogenase and telomerase reverse transcriptase promoter mutations for predicting clinical outcomes in patients with lower-grade gliomas

Objective To investigate the prognostic values of isocitrate dehydrogenase (IDH) and telomerase reverse transcriptase (TERT) promoter mutations in patients with lower-grade gliomas. Methods 260 patients with pathological diagnosis of lower-grade gliomas (WHO Ⅱ and WHOⅢ) were enrolled in the study, and their data were collected. Kaplan-Meier method was used to calculate the survival rates. Cox regression model was used to conduct multivariate analysis. Results The median survival time for IDH mut and IDH wt subgroups were 42.00 and 27.55 months with statistical significane (P=0.001). The median survival time for TERT mut and TERT wt subgroups were 42.00 and 33.50 months, respectively (P=0.660). The survival analysis for IDH/TERT combination demonstrated that the suvival of IDH wt/TERT mut subgroup was the worst (P=0.001), the survival of IDH mut subgroups were favourable (P=0.001). Conclusion IDH mutation has strong prognostic values for the survival of lower-grade gliomas. And TERT promoter mutation could contribute to IDH mutation in predicting the survival of lower-grade gliomas. IDH/TERT mutations could be significant prognostic factors influencing the survival of lower-grade gliomas. Key words: Isocitrate dehydrogenase; Telomerase reverse transcriptase; Lower-grade gliomas; Prognosis

A quantitative detection method for glioma IDH1 R132H mutation based on pyrosequencing

Objective To develop a method based on pyrosequencing that can be used to accurately and quantitatively detect the IDH1 R132H mutation of gliomas and to evaluate the clinical application of that method. Methods Thirty cases of formalin-fixed and parrffin-embedded (FFPE) samples of gliomas and clinical database were retrospectively obtained from the Chinese Glioma Genome Atlas (CGGA). There are 15 IDH1 wild type and 15 IDH1 R132H mutant samples. The pyrosequencing results were compared with the findings of immunohistochemistry. Results The pyrosequencing results indicated that the percentage of CAT in glioma sample ranged from 10% to 52% in all 30 cases. The percentage of CAT in IDH1 R132H mutant glioma was less than 19%, while the percentage of CAT in IDH1 R132H wildtype glioma was more than 27%. Immunohistochemistry results indicated negative staining in 15 samples and positive staining in the other 15 samples including 8 positive staining and 7 strong positive staining. Further statistical analysis showed that the quantitative IDH1 R132H mutant ratios of pyrosequencing were significantly different between immunohistochemistry-negative and immunohistochemistry-positive glioma FFPE samples, and the former was below 20% (10%-18%), while the latter was above 20% (28%-52%). Conclusion The quantitative IDH1 R132H mutant detection method based on pyrosequencing could accurately detect the IDH1 R132H mutant level in FFPE glioma samples, which seems suitable for routine molecular pathological practice. Key words: Glioma; Pathology, molecular; Mutation; Isocitrate dehydrogenase 1; Pyrosequencing

Factors Differentiating the Effectiveness of Polyprotic Acids as Inhibitors of Calcium Oxalate Crystallization in Kidney Stone Disease

Pathological crystallization of calcium oxalate monohydrate (COM) is a critical process in human kidney stone disease. Methods of curtailing COM growth involve the action of natural and synthetic polyprotic acids, which selectively bind to crystal surfaces and inhibit the anisotropic rates of growth. Here we use a combination of bulk crystallization, in situ scanning probe microscopy, density functional theory, and physiologically relevant in vitro assays to elucidate the molecular origins of COM growth inhibition, focusing on citrate (CA) and its molecular analogues hydroxycitrate (HCA) and isocitrate (ICA). These three molecules differ only in the number and/or placement of hydroxyl groups, yet each exhibit unique binding modes to COM crystal surfaces. A major breakthrough in the development of potential therapies came from the recent discovery of HCA being a potent inhibitor possessing an ability to dissolve crystal surfaces in supersaturated media. Using a combination of experiments and computational calculations, we examine the differentiating factors for isostructural analogues of citrate to prompt dissolution and introduce a vectorized displacement parameter that accounts for strain induced on a crystal lattice as a result of inhibitor adsorption. We also compare the inhibitory effects of all three polyprotic acids in a human urine assay that surprisingly revealed HCA to be a far superior inhibitor than laboratory estimates owing to an apparent synergistic cooperative effect with species in the urine milieu. Collectively, these findings identify new inhibitors of calcium oxalate crystallization and demonstrate that HCA and ICA are promising alternatives to citrate, the current therapy.

Advances in targeted treatment of acute myeloid leukemia

Chemotherapy is still the main treatment of acute myeloid leukemia (AML) for the moment. The successful use of imatinib in chronic myeloid leukemia has accelerated the study of targeted therapy. With the development of next generation sequencing, researchers have a complete understanding of AML gene mutation profile. Based on that, scientists have tried to develop small molecular targeted drugs. There is no new drug for AML approved for several decades, until the United States Food and Drug Administration (FDA) approved four drugs for AML in 2017. So 2017 can be considered as the year of AML. These new drugs have been recommended in the National Comprehensive Cancer Network (NCCN) guidelines (2018) and have become the first line treatment of AML. In addition to the four approved new drugs, many drugs are in clinical trials or in preclinical stage. When more new drugs are approved in the future, the treatment of AML will truly enter the era of targeted therapy or precision therapy. This article summarizes the AML targeting drugs that have been approved and might be approved in the future, mainly including Fms-like tyrosine kinase (FLT)3 inhibitors, isocitrate dehydrogenase (IDH) inhibitors, B-cell lymphoma (BCL)2 inhibitors, immunotoxins and so on. Key words: Leukemia, myeloid, acute; Molecular targeted therapy; FLT3 inhibitors; IDH inhibitors; BCL2 inhibitors; GO; SGN-CD33A

Correlation analysis between glioblastoma perfusion imaging and isocitrate dehydrogenase 1 mutation status

Objective To investigate the value of perfusion imaging in predicting the status of isocitrate dehydrogenase 1 (IDH1) in glioblastoma. Methods Retrospectively studied 30 patients with glioblastoma multiforme with wild type IDH1 (IDHw) and 30 patients with mutant IDH1 (IDH1m) in Department of Neurosurgery, Shanxi Provincial People′s Hospital from September 2014 to February 2016. Ktrans and Ve within the enhancing portion of each tumor were measured by using DCE-MRI data. rCBF and rCBV within the enhancing portion of each tumor were measured by using DSC-MRI. Four parameters were represented as ±s, each of the 4 parameters was compared between patients with wild type IDH1 and mutant IDH1 by using the t-test. The performance in discriminating between the two entities was evaluated by using receiver operating characteristic analysis. Results Ktrans, Ve, rCBF and rCBV inside the enhancing lesion were significantly higher in patients with wild type IDH1 than in those with mutant IDH1.There was a statistically significant difference between IDH1w group and IDH1m group of rCBF value (P<0.05). The area under the curve for Ktrans, Ve, rCBF, and rCBV inside the enhancing lesion were 0.850, 0.873, 0.739 and 0.772, respectively. The value of rCBF value of the Ktrans value Ve value of IDH1w was significantly higher than that of IDH1m(P<0.05) in the value of the Ktrans value Ve value of rCBF, the value of the AUC value in rCBV was not significantly different with the combination of the 4 parameters of the diagnostic performance (AUC=0.915). Conclusions Ktrans, Ve, rCBF and rCBV calculated from MRI are useful for predicting the IDH1 mutation status. This method is not only for the classification of brain glioblastoma diagnosis has important value, and in glioblastoma classification is of important value in the preoperative noninvasive evaluation, and it has reference significance for predicting the prognosis of patients. Key words: Glioblastoma; Perfusion imaging; Mutation; Isocitrate dehydrogenase 1

Progress in clinical research of citrate dehydrogenase in glioma

Glioma is the most common malignant tumor of the nervous system. The discovery of IDH (isocitrate, dehydrogenase) gene mutation has pointed out a new direction for the study of glioma. IDH and the pathogenesis of glioma have been studied more and more, and the relationship between IDH and diagnosis, treatment, prognosis of glioma and other clinical problems have attracted more and more scholars’ attention. This article summarizes the relationship between IDH gene mutation and glioma and its application in clinical research of glioma, and provides a new target and research direction for drug therapy of glioma. Key words: Glioma; Isocitrate dehydrogenase; Gene mutation

Novel Insights for Inhibiting Mutant Heterodimer IDH1wt-R132H in Cancer: An In-Silico Approach.

Isocitrate dehydrogenase 1 (IDH1) is a dimeric enzyme responsible for supplying the cell's nicotinamide adenine dinucleotide phosphate (NADPH) reserves via dehydrogenation of isocitrate (ICT) and reduction of NADP+. Mutations in position R132 trigger cancer by enabling IDH1 to produce D-2-hydroxyglutarate (2-HG) and reduce inhibition by ICT. Mutant IDH1 can be found as a homodimer or a heterodimer. We propose a novel strategy to inhibit IDH1 R132 variants as a means not to decrease the concentration of 2-HG but to provoke a cytotoxic effect, as the cell malignancy at this point no longer depends on 2-HG. We aim to inhibit the activity of the mutant heterodimer to block the wild-type subunit. Limiting the NADPH reserves in a cancerous cell will enhance its susceptibility to the oxidative stress provoked by chemotherapy. We performed a virtual screening using all US FDA-approved drugs to replicate the loss of inhibition of mutant IDH1 by ICT. We characterized our results based on molecular interactions and correlated them with the described phenotypes. We replicated the loss of inhibition by ICT in mutant IDH1. We identified 20 drugs with the potential to inhibit the heterodimeric isoform. Six of them are used in cancer treatment. We present 20 FDA-approved drugs with the potential to inhibit IDH1 wild-type activity in mutated cells. We believe this work may provide important insights into current and new approaches to dealing with IDH1 mutations. In addition, it may be used as a basis for additional studies centered on drugs presenting differential sensitivities to different IDH1 isoforms.

Sellar/suprasellar extraventricular neurocytoma

Objective To explore the clinicopathological features of extraventricular neurocytoma located in the sellar/suprasellar region. Methods The clinical manifestations, neuroimaging, histopathological, immunohistochemical and molecular genetic features were retrospectively analyzed in one case of sellar/suprasellar extraventricular neurocytoma, and the related literatures were reviewed. Results A 27-year-old female presented with intermittent headache, accompanied by blurred vision for 5 months. Head MRI demonstrated a mass with a well-defined margin measuring 3.80 cm × 2.50 cm × 3.40 cm located in the sellar/suprasellar region. The tumor showed isointense to hyperintense signals on T 1 WI and hyper-hypointense mixed signals on T 2 WI, and slightly hyperintense signal on diffusion-weighted imaging (DWI). The pituitary was not shown. A transsphenoidal sellar tumor resection, cerebrospinal fluid (CSF) rhinorrhea repairing and optic decompression were performed. The mass was lightly yellow and tough with abundant blood supply and filled with old hemorrhage. The pituitary tissue was pushed to the left rear. Microscopy examination showed a diffuse invasive growth pattern with neuropil background in some area. The tumor cells were uniform on size and shape with round to oval, exquisite and hyperchromatic nuclei. No mitosis was found. Immunohistochemical staining showed the tumor cells were positive for neuronal nuclei (NeuN) and thyroid transcription factor-1 (TTF-1) in nuclei, calretinin (CR) in nuclei and cytoplasm, synaptophysin (Syn), chromogranin A (CgA), E-cadherin, matrix metalloproteinase-9 (MMP-9) in cytoplasm, and focally positive for S-100 protein (S-100) in nuclei, and neurofilament protein (NF), cytokeratin 8 (CK8) and vimentin (Vim) in cytoplasm. The Ki-67 labeling index was about 3%. The tumor tissue was negative for reticular fiber staining. Molecular genetic analysis showed that isocitrate dehydrogenasel (IDH) gene was not mutated, and 1p/19q was intact in tumor cells. The final pathological diagnosis was extraventricular neurocytoma, WHO grade Ⅱ. Conclusions Extraventricular neurocytoma located in the sellar/suprasellar region is very rare. The histological features are similar to central neurocytoma in ventricle. Tumor cells were in diffusely invasive growth and were uniform in size and shape, with round nuclei. Fibrillary areas mimicking neurophil and branching thin-walled capillaries can be seen. The differential diagnosis includes pituitary adenoma, oligodendroglioma, clear cell ependymoma, and so on. DOI: 10.3969/j.issn.1672-6731.2017.12.009

The overexpression of IDH1 R132H mutant mediated by lentivirus inhibits tumorsphere formation in glioma cells LN229

Objective To explore the effects of the lentivirus-mediated over-expression of the IDH1-R132H mutant gene on the tumorsphere formation of glioma cells LN229. Methods The recombinant lentivirus vector IDH1 R132H mutant was packaged and then infected LN229, U87 and H4 glioma cell lines with lentivirus particles. Stably infected cell lines were established using puromycin resistance selection. The expression of IDH1 R132H mutant was observed using fluorescence microscope and estimated by Western blot. For evaluation of the abilities of LN229 cell to form tumorspheres after the transfection of IDH1 R132H mutant, a sphere growth assay was applied by culturing cells in serum-free medium plus B27 supplement, EGF and bFGF. Results Sanger sequencing revealed that we got an IDH1 R132H mutant lentiviral expression vector successfully and green fluorescence was observed by fluorescence microscopy. Western blot analyses revealed protein expression of IDH1 R132H mutant in cells transfected with IDH1 R132H mutant which was absent in the control groups.Moreover, the sphere growth assay showed that the cells transfected with IDH1 R132H were recombined with lentivirus vectors and, compared with the control group, had lower tumorsphere formation abilities(P<0.05). Conclusions The expression of recombinant IDH1 R132H mutant vector mediated by lentivirus inhibits tumorsphere formation in glioma cells LN229, which suggests a potential role in the stemness of gliomas. Key words: Glioma; Isocitrate dehydrogenase 1; Lentiviral expression vector; Transfection; Tumorsphere formation

Molecular mechanisms of isocitrate dehydrogenase 1 (IDH1) mutations identified in tumors: The role of size and hydrophobicity at residue 132 on catalytic efficiency

Isocitrate dehydrogenase 1 (IDH1) catalyzes the reversible NADP+-dependent conversion of isocitrate (ICT) to α-ketoglutarate (αKG) in the cytosol and peroxisomes. Mutations in IDH1 have been implicated in >80% of lower grade gliomas and secondary glioblastomas and primarily affect residue 132, which helps coordinate substrate binding. However, other mutations found in the active site have also been identified in tumors. IDH1 mutations typically result in a loss of catalytic activity, but many also can catalyze a new reaction, the NADPH-dependent reduction of αKG to d-2-hydroxyglutarate (D2HG). D2HG is a proposed oncometabolite that can competitively inhibit αKG-dependent enzymes. Some kinetic parameters have been reported for several IDH1 mutations, and there is evidence that mutant IDH1 enzymes vary widely in their ability to produce D2HG. We report that most IDH1 mutations identified in tumors are severely deficient in catalyzing the normal oxidation reaction, but that D2HG production efficiency varies among mutant enzymes up to ∼640-fold. Common IDH1 mutations have moderate catalytic efficiencies for D2HG production, whereas rarer mutations exhibit either very low or very high efficiencies. We then designed a series of experimental IDH1 mutants to understand the features that support D2HG production. We show that this new catalytic activity observed in tumors is supported by mutations at residue 132 that have a smaller van der Waals volume and are more hydrophobic. We report that one mutation can support both the normal and neomorphic reactions. These studies illuminate catalytic features of mutations found in the majority of patients with lower grade gliomas.

Research progress of novel drugs for treatment of acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common subtype of leukemia in adult. Standard combined chemotherapy and hematopoietic stem cell transplantation (HSCT) are the major treatment of AML. In recent years, advances in molecular biology area, such as the completion of the human genome project, and next-generation sequencing, have brought new direction to anti-AML drugs, such as FMS-like tyrosine kinase (FLT) inhibitor, isocitrate dehydrogenase (IDH) 1/2 inhibitor, histone deacetylase (HDAC) inhibitor, epigenetic drugs, novel chemotherapeutic drug CPX-351, as well as CD33 antibody as the representative of antibody immunotherapy and chimeric antigen receptor T cell (CAR-T) immunotherapy. In this brief review, we presents an overview of novel agents currently in clinical trials that have data published or be hopeful to be used in clinic in treatment of AML. Key words: Leukemia, myeloid, acute; Drugs, investigational; Fms-Like tyrosine kinase 3; Isocitrate dehydrogenase; Histone deacetylase inhibitors; Immunotherapy

Molecular mechanism of the allosteric regulation of the \u03b1\u03b3 heterodimer of human NAD-dependent isocitrate dehydrogenase

Human NAD-dependent isocitrate dehydrogenase catalyzes the decarboxylation of isocitrate (ICT) into α-ketoglutarate in the Krebs cycle. It exists as the α2βγ heterotetramer composed of the αβ and αγ heterodimers. Previously, we have demonstrated biochemically that the α2βγ heterotetramer and αγ heterodimer can be allosterically activated by citrate (CIT) and ADP. In this work, we report the crystal structures of the αγ heterodimer with the γ subunit bound without or with different activators. Structural analyses show that CIT, ADP and Mg2+ bind adjacent to each other at the allosteric site. The CIT binding induces conformational changes at the allosteric site, which are transmitted to the active site through the heterodimer interface, leading to stabilization of the ICT binding at the active site and thus activation of the enzyme. The ADP binding induces no further conformational changes but enhances the CIT binding through Mg2+-mediated interactions, yielding a synergistic activation effect. ICT can also bind to the CIT-binding subsite, which induces similar conformational changes but exhibits a weaker activation effect. The functional roles of the key residues are verified by mutagenesis, kinetic and structural studies. Our structural and functional data together reveal the molecular mechanism of the allosteric regulation of the αγ heterodimer.