Ashish Chugh

Oncostatin-M Differentially Regulates Mesenchymal and Proneural Signature Genes in Gliomas via STAT3 Signaling

Glioblastoma (GBM), the most malignant of the brain tumors is classified on the basis of molecular signature genes using TCGA data into four subtypes- classical, mesenchymal, proneural and neural. The mesenchymal phenotype is associated with greater aggressiveness and low survival in contrast to GBMs enriched with proneural genes. The proinflammatory cytokines secreted in the microenvironment of gliomas play a key role in tumor progression. The study focused on the role of Oncostatin-M (OSM), an IL-6 family cytokine in inducing mesenchymal properties in GBM. Analysis of TCGA and REMBRANDT data revealed that expression of OSMR but not IL-6R or LIFR is upregulated in GBM and has negative correlation with survival. Amongst the GBM subtypes, OSMR level was in the order of mesenchymal > classical > neural > proneural. TCGA data and RT-PCR analysis in primary cultures of low and high grade gliomas showed a positive correlation between OSMR and mesenchymal signature genes-YKL40/CHI3L1, fibronectin and vimentin and a negative correlation with proneural signature genes-DLL3, Olig2 and BCAN. OSM enhanced transcript and protein level of fibronectin and YKL-40 and reduced the expression of Olig2 and DLL3 in GBM cells. OSM-regulated mesenchymal phenotype was associated with enhanced MMP-9 activity, increased cell migration and invasion. Importantly, OSM induced mesenchymal markers and reduced proneural genes even in primary cultures of grade-III glioma cells. We conclude that OSM-mediated signaling contributes to aggressive nature associated with mesenchymal features via STAT3 signaling in glioma cells. The data suggest that OSMR can be explored as potential target for therapeutic intervention.

Suppression of the invasive potential of Glioblastoma cells by mTOR inhibitors involves modulation of NFκB and PKC-α signaling

Glioblastoma (GBM) is the most aggressive type of brain tumors in adults with survival period <1.5 years of patients. The role of mTOR pathway is documented in invasion and migration, the features associated with aggressive phenotype in human GBM. However, most of the preclinical and clinical studies with mTOR inhibitors are focused on antiproliferative and cytotoxic activity in GBM. In this study, we demonstrate that mTOR inhibitors-rapamycin (RAP), temisirolimus (TEM), torin-1 (TOR) and PP242 suppress invasion and migration induced by Tumor Necrosis Factor-α (TNFα) and tumor promoter, Phorbol 12-myristate 13-acetate (PMA) and also reduce the expression of the TNFα and IL1β suggesting their potential to regulate factors in microenvironment that support tumor progression. The mTOR inhibitors significantly decreased MMP-2 and MMP-9 mRNA, protein and activity that was enhanced by TNFα and PMA. The effect was mediated through reduction of Protein kinase C alpha (PKC-α) activity and downregulation of NFκB. TNFα- induced transcripts of NFκB targets -VEGF, pentraxin-3, cathepsin-B and paxillin, crucial in invasion were restored to basal level by these inhibitors. With limited therapeutic interventions currently available for GBM, our findings are significant and suggest that mTOR inhibitors may be explored as anti-invasive drugs for GBM treatment.

Secretory prostate apoptosis response (Par)‐4 sensitizes multicellular spheroids (MCS) of glioblastoma multiforme cells to tamoxifen‐induced cell death

Glioblastoma multiforme (GBM) is the most malignant form of brain tumor and is associated with resistance to conventional therapy and poor patient survival. Prostate apoptosis response (Par)‐4, a tumor suppressor, is expressed as both an intracellular and secretory/extracellular protein. Though secretory Par‐4 induces apoptosis in cancer cells, its potential in drug‐resistant tumors remains to be fully explored. Multicellular spheroids (MCS) of cancer cells often acquire multi‐drug resistance and serve as ideal experimental models. We investigated the role of Par‐4 in Tamoxifen (TAM)‐induced cell death in MCS of human cell lines and primary cultures of GBM tumors. TCGA and REMBRANT data analysis revealed that low levels of Par‐4 correlated with low survival period (21.85 ± 19.30 days) in GBM but not in astrocytomas (59.13 ± 47.26 days) and oligodendrogliomas (58.04 ± 59.80 days) suggesting low PAWR expression as a predictive risk factor in GBM. Consistently, MCS of human cell lines and primary cultures displayed low Par‐4 expression, high level of chemo‐resistance genes and were resistant to TAM‐induced cytotoxicity. In monolayer cells, TAM‐induced cytotoxicity was associated with enhanced expression of Par‐4 and was alleviated by silencing of Par‐4 using specific siRNA. TAM effectively induced secretory Par‐4 in conditioned medium (CM) of cells cultured as monolayer but not in MCS. Moreover, MCS were rendered sensitive to TAM‐induced cell death by exposure to conditioned medium (CM)‐containing Par‐4 (derived from TAM‐treated monolayer cells). Also TAM reduced the expression of Akt and PKCζ in GBM cells cultured as monolayer but not in MCS. Importantly, combination of TAM with inhibitors to PI3K inhibitor (LY294002) or PKCζ resulted in secretion of Par‐4 and cell death in MCS. Since membrane GRP78 is overexpressed in most cancer cells but not normal cells, and secretory Par‐4 induces apoptosis by binding to membrane GRP78, secretory Par‐4 is an attractive candidate for potentially overcoming therapy‐resistance not only in malignant glioma but in broad spectrum of cancers.

The role of transforaminal percutaneous endoscopic discectomy in lumbar disc herniations

Objectives: To study 1)the efficacy of transforaminal percutaneous endoscopic lumbar discectomy in lumbar disc herniations.2) limitations and advantages of the surgical procedure. 3)morbidity and complications associated with the procedure. Materials and Methods: This study was carried out on 120 patients who had single level herniated disc Pre-operative assessment of VAS and MSS scoring systems were documented one day prior to surgery. Post operative results were determined by MacNab criteria and by modified Suezawa and Schreiber clinical scoring system (MSS score). Results: Maximum patients were in the age group of 31 to 40 years and 83.43% of the patients were males. 80% patients had lumbar disc herniation at L4-L5 level, The mean operative time of endoscopic discectomy was 52.28 minutes and the mean hospital stay was 2.1days .8 cases of L5-S I were abandoned due to high iliac bone and hence their disc could not be accessed.Out of 112 patients who underwent operation, 2 patients developed discitis and 1 was found to have dysesthesia. Also recurrent prolapsed intervertebral disc was seen in 6 cases The mean preoperative and 6 months follow up VAS score was 8.4 and 1.89 respectively. Mean preoperative and 6 months follow up Modified Suezawa And Schreiber Clinical Scoring System(MSS Score) was 3.47 and 7.92 respectively.MSS score showed excellent and good outcome in 82.12% patients and Modified Macnab Criteria showed excellent and good outcome in 89.3% patients at 6months follow up. Conclusion: TPELD can be a reasonable alternative to conventional microscopic discectomy for the treatment of patients with LDH. We also conclude that TPELD is not an effective procedure for L5 -S 1 disc and an open procedure should be opted for better outcomes.

Mammalian target of rapamycin inhibitors, temsirolimus and torin 1, attenuate stemness-associated properties and expression of mesenchymal markers promoted by phorbol-myristate-acetate and oncostatin-M in glioblastoma cells

The phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin signaling pathway is crucial for tumor survival, proliferation, and progression, making it an attractive target for therapeutic intervention. In glioblastoma, activated mammalian target of rapamycin promotes invasive phenotype and correlates with poor patient survival. A wide range of mammalian target of rapamycin inhibitors are currently being evaluated for cytotoxicity and anti-proliferative activity in various tumor types but are not explored sufficiently for controlling tumor invasion and recurrence. We recently reported that mammalian target of rapamycin inhibitors—rapamycin, temsirolimus, torin 1, and PP242—suppressed invasion and migration promoted by tumor necrosis factor-alpha and phorbol-myristate-acetate in glioblastoma cells. As aggressive invasion and migration of tumors are associated with mesenchymal and stem-like cell properties, this study aimed to examine the effect of mammalian target of rapamycin inhibitors on these features in glioblastoma cells. We demonstrate that temsirolimus and torin 1 effectively reduced the constitutive as well as phorbol-myristate-acetate/oncostatin-M-induced expression of mesenchymal markers (fibronectin, vimentin, and YKL40) and neural stem cell markers (Sox2, Oct4, nestin, and mushashi1). The inhibitors significantly abrogated the neurosphere-forming capacity induced by phorbol-myristate-acetate and oncostatin-M. Furthermore, we demonstrate that the drugs dephosphorylated signal transducer and activator transcription factor 3, a major regulator of mesenchymal and neural stem cell markers implicating the role of signal transducer and activator transcription factor 3 in the inhibitory action of these drugs. The findings demonstrate the potential of mammalian target of rapamycin inhibitors as “stemness-inhibiting drugs” and a promising therapeutic approach to target glioma stem cells.

Primary angiosarcoma of the skull: A rare case report

Background: Angiosarcomas are rare high grade endothelial tumors characterized by rapidly proliferating anaplastic cells derived from blood vessels and lining irregular blood filled spaces. Primary neoplasms of the skull are rare, representing 2.6% of primary neoplasms of bone. Primary malignant neoplasms of the skull are even rarer, accounting for only 0.8% of primary malignant neoplasms of bone. Case Description: We report a 32-year-old female who presented with right parieto-occipital swelling, which gradually increased in size. Radiology was suggestive of a calvarial soft tissue lesion in the right parieto-occipital region with destruction of the adjacent parieto-occipital bone with intracranial extra-axial extension. Complete surgical excision of the calvarial lesion was done under general anesthesia. Postoperative computed tomography (CT) scan of brain (plain and with contrast) showed complete excision of the tumor mass. Histopathological diagnosis was consistent with ‘an angiosarcoma of the skull’. On immunohistochemistry, the atypical endothelial cells were highlighted by CD34, CD31, and factor VIII-related antigen. The patient received adjuvant radiotherapy to the tumor bed. Conclusion: Primary angiosarcoma of the skull is a rare tumor with less than 20 cases reported worldwide till date. The treatment should include complete surgical excision with a wide bony margin followed by adjuvant radiotherapy, which in our case has given a good locoregional control even at the end of 2 years. However, these patients should be followed up with repeated scans yearly to rule out locoregional as well as distant recurrence.

A rare case report of cerebral phaeohyphomycosis mimicking glioma in a patient of rheumatic valvular heart disease

Phaeohyphomycosis is a collective term used for fungal infections caused by moulds and yeasts that have brown pigmented cell walls due to the presence of melanin. These are also known as dematiaceous fungi. We report this patient who presented with headache, right hemiparesis, slurred speech, and altered sensorium. Patient was a known case of rheumatic valvular heart disease (RVHD) and had undergone balloon valvotomy for mitral stenosis 1 year back. Radiological features were suggestive of high grade glioma. Left fronto-parietal decompressive craniectomy with complete excision of mass lesion was performed. Histopathological examination of the surgical specimen revealed multiple granulomas with giant cells. These giant cells contained branched septate pigmented fungal hyphae in their cytoplasm. After the histopathology report, patient was started on intravenous amphotericin and was discharged on oral itraconazole 200 mg twice daily. Unfortunately, the patient was non-compliant and stopped taking oral itraconazole after 1 month. He landed up in fulminant fungal meningo-encephalitis and died 10 weeks after the initial diagnosis. We report a rare case of cerebral phaeohyphomycosis in a patient of RVHD which, to our knowledge, is nowhere mentioned in the literature.