Leili Mirsadraei

Persistent Diffusion-Restricted Lesions in Bevacizumab-Treated Malignant Gliomas Are Associated with Improved Survival Compared with Matched Controls

BACKGROUND AND PURPOSE: A subset of patients with malignant glioma develops conspicuous lesions characterized by persistent restricted diffusion during treatment with bevacizumab. The purpose of the current study was to characterize the evolution of these lesions and to determine their relationship to patient outcome. MATERIALS AND METHODS: Twenty patients with malignant glioma with persistent restricted-diffusion lesions undergoing treatment with bevacizumab were included in the current study. Mean ADC and the volume of restricted diffusion were computed for each patient during serial follow-up. Differences in TTP, TTS, and OS were compared between patients with restricted diffusion and matched controls by using Kaplan-Meier analysis with the logrank test and Cox hazard models. RESULTS: Mean ADC values were generally stable with time (mean, 5.2 ± 12.6% change from baseline). The volume of restricted diffusion increased a median of 23% from baseline by 6 months. Patients with restricted-diffusion lesions had significantly greater TTP (logrank, P = .013), TTS (logrank, P = .008), and OS (logrank, P = .010) than matched controls. When available, advanced physiologic imaging of restricted-diffusion lesions showed hypovascularity on perfusion MR imaging and decreased amino acid uptake on 18F-FDOPA PET scans. Atypical gelatinous necrotic tissue was confirmed in the area of restricted diffusion in 1 patient. CONCLUSIONS: Restricted-diffusion lesions in malignant gliomas treated with bevacizumab are generally stable with time and are associated with improved outcomes. These results combined with physiologic imaging and histopathologic data suggest that these lesions are not consistent with aggressive tumor.

Differential Gene Expression in Glioblastoma Defined by ADC Histogram Analysis: Relationship to Extracellular Matrix Molecules and Survival

BACKGROUND AND PURPOSE: ADC histogram analysis can stratify outcomes in patients with GBM treated with bevacizumab. Therefore, we compared gene expression between high-versus-low ADC tumors to identify gene expression modules that could underlie this difference and impact patient prognosis. MATERIALS AND METHODS: Up-front bevacizumab-treated patients (N = 38) with newly diagnosed glioblastoma were analyzed by using an ADC histogram approach based on enhancing tumor. Using microarrays, we compared gene expression in high-versus-low ADC tumors in patients subsequently treated with bevacizumab. Tissue sections from a subset of tumors were stained for collagen and collagen-binding proteins. Progression-free and overall survival was determined by using Cox proportional hazard ratios and the Kaplan-Meier method with the log rank test. RESULTS: A total of 13 genes were expressed at 2-fold or greater levels in high- compared with low-ADC tumors at the P < .05 level. Of these, 6 encode for collagen or collagen-binding proteins. High gene expression for the collagen-binding protein decorin was associated with shorter survival (HR, 2.5; P = .03). The pattern and degree of collagen staining were highly variable in both high- and low-ADC tumors. CONCLUSIONS: High-ADC GBMs show greater levels of ECM protein gene expression compared with low-ADC GBMs. It is unclear whether this translates to the accumulation of higher levels of the encoded proteins. However, because ECM molecules could contribute to a proinvasive phenotype, this relationship merits further investigation.

A review of room temperature storage of biospecimen tissue and nucleic acids for anatomic pathology laboratories and biorepositories.

UNLABELLED Frozen biospecimens are crucial for translational research and contain well-preserved nucleic acids and protein. However, the risks of freezer failure as well as space, cost, and environmental concerns of frozen biospecimens are substantial. OBJECTIVE The purpose of the study was to review the current status of room temperature biospecimen storage. METHODS We searched Pubmed and vendor websites to identify relevant information. RESULTS Formalin-fixed paraffin embedded (FFPE) tissues have great value but their use is limited by cross-linking and fragmentation of nucleic acids, as well as loss of enzymatic activity. Stabilization solutions can now robustly preserve fresh tissue for up to 7days at room temperature. For longer term storage, commercial vendors of chemical matrices claim real time stability of nucleic acids of over 2 years and their accelerated aging studies to date suggest stability for 12years for RNA and 60years for DNA. However, anatomic pathology biorepositories store mostly frozen tissue rather than nucleic acids. Small quantities of tissue can be directly placed on some chemical matrices to stabilize DNA, however RNA and proteins are not preserved. Current lyophilization approaches can preserve histomorphology, DNA, RNA, and proteins though RNA shows moderate degradation after 1-2years. Formalin-free fixatives show improved but varying abilities to preserve nucleic acids and face validation as well as cost barriers in replacing FFPE specimens. The paraffin embedding process can degrade RNA. CONCLUSION Development of robust long-term room temperature biospecimen tissue storage technology can potentially reduce costs for the biomedical community in the face of growing targeted therapy needs and decreasing budgets.

Evidence for orphan nuclear receptor TR4 in the etiology of Cushing disease

Cushing disease (CD) is a life-threatening disorder attributed to excess pituitary tumor-derived adrenocorticotrophic hormone (ACTH) and adrenal steroid secretion caused by pituitary tumors. Whereas CD was first described in 1932, the underlying genetic basis driving tumor growth and ACTH secretion remains unsolved. Here, we show that testicular orphan nuclear receptor 4 (TR4, nuclear receptor subfamily 2, group C, member 2) is overexpressed in human corticotroph tumors as well as in human and mouse corticotroph tumor cell lines. Forced overexpression of TR4 in both human and murine tumor cells increased proopiomelanocortin transcription, ACTH secretion, cellular proliferation, and tumor invasion rates in vitro. Conversely, knockdown of TR4 expression reversed all phenotypes. Mechanistically, we show that TR4 transcriptionally activates proopiomelanocortin through binding of a direct repeat 1 response element in the promoter, and that this is enhanced by MAPK-mediated TR4 phosphorylation. In vivo, TR4 overexpression promotes murine corticotroph tumor growth as well as enhances ACTH and corticosterone production, whereas TR4 knockdown decreases circulating ACTH and corticosterone levels in mice harboring ACTH-secreting tumors. Our findings directly link TR4 to the etiology of corticotroph tumors, hormone secretion, and cell growth as well as identify it as a potential target in the treatment of CD.

Detection of 2-hydroxyglutaric acid in vivo by proton magnetic resonance spectroscopy in U87 glioma cells overexpressing isocitrate dehydrogenase-1 mutation

The arginine 132 (R132) mutation of isocitrate dehydrogenase -1 (IDH1(R132)) results in production of 2-hydroxyglutarate (2-HG) and is associated with a better prognosis compared with wild-type (WT) in glioma patients. The majority of lower-grade gliomas express IDH1(R132), whereas this mutation is rare in grade IV gliomas. The aim of this study was to noninvasively investigate metabolic and physiologic changes associated with the IDH1 mutation in a mouse glioma model. Using a 7T magnet, we compared MRI and proton magnetic resonance spectroscopy (MRS) in U87 glioma cells overexpressing either the mutated IDH1(R132) or IDH1 wild-type (IDH1(WT)) gene in a mouse flank xenograft model. Flank tumors overexpressing IDH1(R132) showed a resonance at 2.25 ppm corresponding to the 2-HG peak described for human IDH1(R132) gliomas. WT tumors lacked this peak in all cases. IDH1 mutant tumors demonstrated significantly reduced glutamate by in vivo MRS. There were no significant differences in T(2), apparent diffusion coefficient (ADC), or perfusion values between the mutant and IDH1(WT) tumors. The IDH1(R132) mutation results in 2-HG resonance at 2.25 ppm and a reduction of glutamate levels as determined by MRS. Our results establish a model system where 2-HG can be monitored noninvasively, which should be helpful in validating 2-HG levels as a prognostic and/or predictive biomarker in glioma.

Primary central nervous system histiocytic sarcoma presenting as a postradiation sarcoma: case report and literature review.

Histiocytic sarcoma (HS) is a rare neoplasm that occurs most commonly in the intestinal tract, skin, soft tissue, and lymph node. The incidence of primary central nervous system (CNS) HS is even rarer, with a total of 6 cases reported in the literature. An etiologic link has not been identified for CNS HS, and the current case of primary CNS HS is unique in that an etiologic link to prior radiation therapy is identified, associated with complex cytogenetic abnormalities in the tumor. Although radiation-associated sarcomas can present as any number of different pathologic entities, this is the first reported case of a radiation-associated CNS HS. The pathologic and immunophenotypic characteristics of this case, with a nearly obscuring heavy inflammatory infiltrate and expression of monocytic/histiocytic markers (CD163, CD68, CD4, fascin), are characteristic of CNS HS. A discussion of the differential diagnosis and review of relevant literature are presented.

Bilateral adrenalectomy: lifesaving procedure in severe Cushing syndrome.

OBJECTIVE To discuss the role of bilateral adrenalectomy in Cushing syndrome, as illustrated in a case of severe hypercortisolism that was unresponsive to combination agent medical therapy. METHODS We report the clinical, laboratory, imaging, and pathologic findings in a patient with ectopic Cushing syndrome attributable to an adrenocorticotropic hormone (ACTH)-secreting neuroblastoma. In addition, we provide a literature review regarding olfactory neuroblastoma and discuss current and emerging therapeutic options for Cushing syndrome. RESULTS A 59-year-old man presented with nasal congestion and neck swelling and was noted to have hypokalemia, hypertension, and hyperglycemia. A nasal biopsy demonstrated a poorly differentiated carcinoma with neuroendocrine features. He was subsequently diagnosed as having ACTH-dependent Cushing syndrome, but despite high-dose combination medical therapy, his condition rapidly deteriorated. Urgent bilateral adrenalectomy provided rapid control of the hypercortisolism, and the patient was later able to undergo an uncomplicated total macroscopic resection of his locally metastatic primary tumor. CONCLUSION This report describes the challenges in the diagnosis and management of ACTH-dependent Cushing syndrome and highlights the important role that bilateral adrenalectomy can still have in patients with severe hypercortisolism causing life-threatening complications.

Nitroxoline induces apoptosis and slows glioma growth in vivo

BACKGROUND Nitroxoline is an FDA-approved antibiotic with potential antitumor activity. Here we evaluated whether nitroxoline has antiproliferative properties on glioma cell growth in vitro and in vivo using glioma cell lines and a genetically engineered PTEN/KRAS mouse glioma model. METHODS The effect of nitroxoline treatment on U87 and/or U251 glioma cell proliferation, cell-cycle arrest, invasion, and ability to induce an apoptotic cascade was determined in vitro. Magnetic resonance imaging was used to measure glioma volumes in genetically engineered PTEN/KRAS mice prior to and after nitroxoline therapy. Induction of apoptosis by nitroxoline was evaluated at the end of treatment using terminal deoxyribonucleotidyl transferase (TDT)-mediated dUTP-digoxigenin nick end labeling (TUNEL). RESULTS Nitroxoline inhibited the proliferation and invasion of glioblastoma cells in a time- and dose-dependent manner in vitro. Growth inhibition was associated with cell-cycle arrest in G1/G0 phase and induction of apoptosis via caspase 3 and cleaved poly(ADP-ribose) polymerase. In vivo, nitroxoline-treated mice had no increase in tumor volume after 14 days of treatment, whereas tumor volumes doubled in control mice. Histological examination revealed 15%-20% TUNEL-positive cells in nitroxoline-treated mice, compared with ∼5% in the control group. CONCLUSION Nitroxoline induces apoptosis and inhibits glioma growth in vivo and in vitro. As an already FDA-approved treatment for urinary tract infections with a known safety profile, nitroxoline could move quickly into clinical trials pending confirmatory studies.

C-terminally truncated form of αB-crystallin is associated with IDH1 R132H mutation in anaplastic astrocytoma

Malignant gliomas are the most common human primary brain tumors. Point mutation of amino acid arginine 132 to histidine (R132H) in the IDH1 protein leads to an enzymatic gain-of-function and is thought to promote gliomagenesis. Little is known about the downstream effects of the IDH1 mutation on protein expression and how and whether changes in protein expression are involved in tumor formation or propagation. In the current study, we used 2D DIGE (difference gel electrophoresis) and mass spectrometry to analyze differences in protein expression between IDH1R132H mutant and wild type anaplastic (grade III) astrocytoma from human brain cancer tissues. We show that expression levels of many proteins are altered in IDH1R132H mutant anaplastic astrocytoma. Some of the most over-expressed proteins in the mutants include several forms of αB-crystallin, a small heat-shock and anti-apoptotic protein. αB-crystallin proteins are elevated up to 22-fold in IDH1R132H mutant tumors, and αB-crystallin expression appears to be controlled at the post-translational level. We identified the most abundant form of αB-crystallin as a low molecular weight species that is C-terminally truncated. We also found that overexpression of αB-crystallin can be induced by transfecting U251 human glioblastoma cell lines with the IDH1R132H mutation. In conclusion, the association of a C-terminally truncated form of αB-crystallin protein with the IDH1R132H mutation is a novel finding that could impact apoptosis and stress response in IDH1 mutant glioma.