Sridevi Hegde

Publications of Sridevi Hegde

• Novel glioblastoma markers with diagnostic and prognostic value identified through transcriptome analysis.

  Authors: Sreekanth P Reddy, Ramona Britto, Katyayni Vinnakota, Hebbar Aparna, Hari Kishore Sreepathi, Balaram Thota, Arpana Kumari, B M Shilpa, M Vrinda, Srikantha Umesh [......] Ashwani Tandon, Paritosh Pandey, Sridevi Hegde, A S Hegde, Anandh Balasubramaniam, B A Chandramouli, Vani Santosh, Paturu Kondaiah, Kumaravel Somasundaram, M R Satyanarayana Rao

  Clinical cancer research : an official journal of the American Association for Cancer Research. 06/2008; 14(10):2978-87.

  PURPOSE: Current methods of classification of astrocytoma based on histopathologic methods are often subjective and less accurate. Although patients with glioblastoma have grave prognosis,PURPOSE: Current methods of classification of astrocytoma based on histopathologic methods are often subjective and less accurate. Although patients with glioblastoma have grave prognosis, significant variability in patient outcome is observed. Therefore, the aim of this study was to identify glioblastoma diagnostic and prognostic markers through microarray analysis. EXPERIMENTAL DESIGN: We carried out transcriptome analysis of 25 diffusely infiltrating astrocytoma samples [WHO grade II--diffuse astrocytoma, grade III--anaplastic astrocytoma, and grade IV--glioblastoma (GBM)] using cDNA microarrays containing 18,981 genes. Several of the markers identified were also validated by real-time reverse transcription quantitative PCR and immunohistochemical analysis on an independent set of tumor samples (n = 100). Survival analysis was carried out for two markers on another independent set of retrospective cases (n = 51). RESULTS: We identified several differentially regulated grade-specific genes. Independent validation by real-time reverse transcription quantitative PCR analysis found growth arrest and DNA-damage-inducible alpha (GADD45alpha) and follistatin-like 1 (FSTL1) to be up-regulated in most GBMs (both primary and secondary), whereas superoxide dismutase 2 and adipocyte enhancer binding protein 1 were up-regulated in the majority of primary GBM. Further, identification of the grade-specific expression of GADD45alpha and FSTL1 by immunohistochemical staining reinforced our findings. Analysis of retrospective GBM cases with known survival data revealed that cytoplasmic overexpression of GADD45alpha conferred better survival while the coexpression of FSTL1 with p53 was associated with poor survival. CONCLUSIONS: Our study reveals that GADD45alpha and FSTLI are GBM-specific whereas superoxide dismutase 2 and adipocyte enhancer binding protein 1 are primary GBM-specific diagnostic markers. Whereas GADD45alpha overexpression confers a favorable prognosis, FSTL1 overexpression is a hallmark of poor prognosis in GBM patients.

• Shift in AP-2alpha localization characterizes astrocytoma progression.

  Authors: Ramona Britto, S Umesh, A S Hegde, Sridevi Hegde, Vani Santosh, B A Chandramouli, Kumaravel Somasundaram

  Cancer biology & therapy. 04/2007; 6(3):413-8.

  Activator protein 2alpha (AP-2alpha) has been shown to be lost in the advanced stages of many cancers, including gliomas. In this study, we wanted to analyze the expression of AP-2alpha inActivator protein 2alpha (AP-2alpha) has been shown to be lost in the advanced stages of many cancers, including gliomas. In this study, we wanted to analyze the expression of AP-2alpha in astrocytoma samples of different grades both at the RNA level, by real-time qPCR and at the protein level, by immunohistochemistry, and to examine its correlation, if any, with patient outcome. Five Grade I, 14 Grade II, 18 Grade III, 72 Grade IV samples and 13 normal brain controls were included. We did not find any clear pattern of regulation at the RNA level with tumor grade. The RNA expression levels however, correlated to a large extent with the nuclear AP-2alpha staining in these samples (72.09%; 31/43). Further, we did not find a complete loss of nuclear AP-2alpha expression in the higher grades, in contrast to previous reports. Interestingly, we found cytoplasmic AP-2alpha expression in a majority of higher grade astrocytomas (Grade IV-85%; 33/39 and Grade III-74%; 14/19) in comparison to lower grades (Grade I-0%; 0/5 and Grade II-37.5%; 3/8) suggesting that the translocation of this protein from the nucleus to the cytoplasm may be responsible for the increased malignancy. The nuclear expression in these grades was found to be concomitantly reduced. Within GBMs, we found that decreased nuclear expression was indicative of a better prognosis. The striking observation was the shift in localization of this protein from the nucleus to the cytoplasm with increasing tumor grade, pointing to a crucial role for this transcription factor in the progression of astrocytomas.

• Upregulation of ASCL1 and inhibition of Notch signaling pathway characterize progressive astrocytoma.

  Authors: Kumaravel Somasundaram, Sreekanth P Reddy, Katyayni Vinnakota, Ramona Britto, Madhavan Subbarayan, Sandeep Nambiar, Aparna Hebbar, Cini Samuel, Mitesh Shetty, Hari Kishore Sreepathi, Vani Santosh, Alangar Sathyaranjandas Hegde, Sridevi Hegde, Paturu Kondaiah, M R S Rao

  Oncogene. 11/2005; 24(47):7073-83.

  Astrocytoma is the most common type of brain cancer constituting more than half of all brain tumors. With an aim to identify markers describing astrocytoma progression, we have carried out microarrayAstrocytoma is the most common type of brain cancer constituting more than half of all brain tumors. With an aim to identify markers describing astrocytoma progression, we have carried out microarray analysis of astrocytoma samples of different grades using cDNA microarray containing 1152 cancer-specific genes. Data analysis identified several differentially regulated genes between normal brain tissue and astrocytoma as well as between grades II/III astrocytoma and glioblastoma multiforme (GBM; grade IV). We found several genes known to be involved in malignancy including Achaete-scute complex-like 1 (Drosophila) (ASCL1; Hash 1). As ASCL has been implicated in neuroendocrine, medullary thyroid and small-cell lung cancers, we chose to examine the role of ASCL1 in the astrocytoma development. Our data revealed that ASCL1 is overexpressed in progressive astrocytoma as evidenced by increased levels of ASCL1 transcripts in 85.71% (6/7) of grade II diffuse astrocytoma (DA), 90% (9/10) of grade III anaplastic astrocytoma (AA) and 87.5% (7/8) of secondary GBMs, while the majority of primary de novo GBMs expressed similar to or less than normal brain levels (66.67%; 8/12). ASCL1 upregulation in progressive astrocytoma is accompanied by inhibition of Notch signaling as seen by uninduced levels of HES1, a transcriptional target of Notch1, increased levels of HES6, a dominant-negative inhibitor of HES1-mediated repression of ASCL1, and increased levels of Notch ligand Delta1, which is capable of inhibiting Notch signaling by forming intracellular Notch ligand autonomous complexes. Our results imply that inhibition of Notch signaling may be an important early event in the development of grade II DA and subsequent progression to grade III AA and secondary GBM. Furthermore, ASCL1 appears to be a putative marker to distinguish primary GBM from secondary GBM.

• Differential protein expression in human gliomas and molecular insights.

  Authors: Vaibhav C Chumbalkar, Chanumolu Subhashini, Vishnu M Dhople, Curam S Sundaram, Medicharla V Jagannadham, Kafnam N Kumar, Pasumarti N B S Srinivas, Ravinutala Mythili, Mulla K Rao, Mahesh J Kulkarni, Sridevi Hegde, Alangar S Hegde, Cini Samual, Vani Santosh, Lalji Singh, Ravi Sirdeshmukh

  Proteomics. 04/2005; 5(4):1167-77.

  Gliomas are the most common of the primary intracranial tumors with astrocytomas constituting about 40%. Using clinically and histologically assessed astrocytomas, we have studied their proteinGliomas are the most common of the primary intracranial tumors with astrocytomas constituting about 40%. Using clinically and histologically assessed astrocytomas, we have studied their protein profiles using a two-dimensional gel electrophoresis-mass spectrometry approach and identified differentially expressed proteins which may be useful molecular indicators to understand these tumors. Examination of the protein profiles of 27 astrocytoma samples of different grades revealed 72 distinct, differentially expressed proteins belonging to various functional groups such as cytoskeleton and intermediate filament proteins, heat shock proteins (HSPs), enzymes and regulatory proteins. Based on the consistency of their differential expression, 29 distinct proteins could be short-listed and may have a role in the pathology of astrocytomas. Some were found to be differentially expressed in both Grade III and IV astrocytomas while others were associated with a particular grade. A notable observation was underexpression of Prohibitin, a potential tumor suppressor protein, Rho-GDP dissociation inhibitor, Rho-GDI, a regulator of Rho GTPases and HSPs as well as destabilization of glial fibrillary acidic protein, GFAP, major protein of the glial filaments, in Grade III malignant tumors. We attempt to explain glioma malignancy and progression in terms of their combined role.

• Alterations in tumour suppressor gene p53 in human gliomas from Indian patients.

  Authors: Poornima Phatak, S Kalai Selvi, T Divya, A S Hegde, Sridevi Hegde, Kumaravel Somasundaram

  Journal of biosciences. 01/2003; 27(7):673-8.

  Alterations in tumour suppressor p53 gene are the most common defects seen in a variety of human cancers. In order to study the significance of the p53 gene in the genesis and development of humanAlterations in tumour suppressor p53 gene are the most common defects seen in a variety of human cancers. In order to study the significance of the p53 gene in the genesis and development of human glioma from Indian patients, we checked 44 untreated primary gliomas for mutations in exons 5-9 of the p53 gene by PCR-SSCP and DNA sequencing. Sequencing analysis revealed six missense mutations. The incidence of p53 mutations was 13.6% (6 of 44). All the six mutations were found to be located in the central core domain of p53, which carries the sequence-specific DNA-binding domain. These results suggest a rather low incidence but a definite involvement of p53 mutations in the gliomas of Indian patients.

• Upregulation of ASCL1 and inhibition of Notch signaling pathway characterize progressive astrocytoma

  Authors: Kumaravel Somasundaram, Sreekanth P Reddy, Katyayni Vinnakota, Ramona Britto, Madhavan Subbarayan, Sandeep Nambiar, Aparna Hebbar, Cini Samuel, Mitesh Shetty, Hari Kishore Sreepathi, Vani Santosh, Alangar Sathyaranjandas Hegde, Sridevi Hegde, Paturu Kondaiah, MRS Rao

  Astrocytoma is the most common type of brain cancer constituting more than half of all brain tumors. With an aim to identify markers describing astrocytoma progression, we have carried out microarrayAstrocytoma is the most common type of brain cancer constituting more than half of all brain tumors. With an aim to identify markers describing astrocytoma progression, we have carried out microarray analysis of astrocytoma samples of different grades using cDNA microarray containing 1152 cancer-specific genes. Data analysis identified several differentially regulated genes between normal brain tissue and astrocytoma as well as between grades II/III astrocytoma and glioblastoma multiforme (GBM; grade IV). We found several genes known to be involved in malignancy including Achaete-scute complex-like1(Drosophila) (ASCL1; Hash 1). As ASCL has been implicated in neuroendocrine, medullary thyroid and small-cell lung cancers, we chose to examine the role of ASCL1 in the astrocytoma development. Our data revealed that ASCL1 is over expressed in progressive astrocytoma as evidenced by increased levels of ASCL1 transcripts in 85.71% (6/7) of grade II diffuse astrocytoma (DA), 90% (9/10) of grade III anaplastic astrocytoma (AA) and 87.5% (7/8) of secondary GBMs, while the majority of primary de novo GBMs expressed similar to or less than normal brain levels (66.67%; 8/12). ASCL1 up regulation in progressive astrocytoma is accompanied by inhibition of Notch signaling as seen by uninduced levels of HES1, a transcriptional target of Notch1, increased levels of HES6, a dominant-negative inhibitor of HES1-mediated repression of ASCL1, and increased levels of Notch ligand Delta1, which is capable of inhibiting Notch signaling by forming intracellular Notch ligand autonomous complexes. Our results imply that inhibition of Notch signaling may be an important early event in the development of grade II DA and subsequent progression to grade III AA and secondary GBM.Furthermore, ASCL1 appears to be a putative marker to distinguish primary GBM from secondary GBM.

• Alterations in tumour suppressor gene p53 in human gliomas from Indian patients

  Authors: Pornima Phatak, Kalai S Selvi, T Divya, AS Hegde, Sridevi Hegde, Kumaravel Somasundaram

  Alterations in the tumour suppressor p53 gene are among the most common defects seen in a variety of human cancers. In order to study the significance of the p53 gene in the genesis and developmentAlterations in the tumour suppressor p53 gene are among the most common defects seen in a variety of human cancers. In order to study the significance of the p53 gene in the genesis and development of human glioma from Indian patients, we checked 44 untreated primary gliomas for mutations in exons 5-9 of the p53 gene by PCR-SSCP and DNA sequencing. Sequencing analysis revealed six missense mutations. The incidence of p53 mutations was 13.6% (6 of 44). All the six mutations were found to be located in the central core domain of p53, which carries the sequence-specific DNA-binding domain. These results suggest a rather low incidence but a definite involvement of p53 mutations in the gliomas of Indian patients.

• Shift in $AP-2\alpha$ Localization Characterizes Astrocytoma Progression

  Authors: Ramona Britto, S Umesh, AS Hegde, Sridevi Hegde, Vani Santosh, BA Chandramouli, Kumaravel Somasundaram

  Activator protein $2\alpha$ $(AP‑2\alpha)$ has been shown to be lost in the advanced stages of many cancers, including gliomas. In this study, we wanted to analyze the expression of $(AP‑2\alpha)$ inActivator protein $2\alpha$ $(AP‑2\alpha)$ has been shown to be lost in the advanced stages of many cancers, including gliomas. In this study, we wanted to analyze the expression of $(AP‑2\alpha)$ in astrocytoma samples of different grades both at the RNA level, by real‑time qPCR and at the protein level, by immunohistochemistry, and to examine its correlation, if any, with patient outcome. Five Grade I, 14 Grade II, 18 Grade III, 72 Grade IV samples and 13 normal brain controls were included. We did not find any clear pattern of regulation at the RNA level with tumor grade. The RNA expression levels however, correlated to a large extent with the nuclear $(AP‑2\alpha)$ staining in these samples (72.09%; 31/43). Further, we did not find a complete loss of nuclear $(AP‑2\alpha)$ expression in the higher grades, in contrast to previous reports. Interestingly, we found cytoplasmic $(AP‑2\alpha)$ expression in a majority of higher grade astrocytomas (Grade IV—85%; 33/39 and Grade III—74%; 14/19) in comparison to lower grades (Grade I—0%; 0/5 and Grade II—37.5%; 3/8) suggesting that the translocation of this protein from the nucleus to the cytoplasm may be responsible for the increased malignancy. The nuclear expression in these grades was found to be concomitantly reduced. Within GBMs, we found that decreased nuclear expression was indicative of a better prognosis. The striking observation was the shift in localization of this protein from the nucleus to the cytoplasm with increasing tumor grade, pointing to a crucial role for this transcription factor in the progression of astrocytomas.

• Differential Expression Of Igfbp Isoforms In Astrocytoma: Prognostic Value Of Igfbp-2,-3, And-5 In Glioblastoma Patients

  Authors: Vani Sanrosh, Anandh Balasubramaniam, Paritosh Panday, BA Chandramouli, AS Hegde, Sridevi Hegde, Kumaravel Somasundaram, Pataru Kondaiah, M Satyanarayanarao

  Insulin-like growth factor binding proteins (IGFBP) are known to modulate the actions of insulin-like growth factors (IGF) mainly by controlling the amount of free IGF that can bind to its receptors.Insulin-like growth factor binding proteins (IGFBP) are known to modulate the actions of insulin-like growth factors (IGF) mainly by controlling the amount of free IGF that can bind to its receptors. IGFBP are also known to regulate cell survival in an IGF-independent pathway. However, they can have a complex bidirectional effect on tumorigenesis. Among the various IGFBP, the expression and role of IGFBP2 in gliomas has been extensively studied. In an earlier gene-expression profiling study on the various grades of astrocytoma, we identified the upregulation of IGFBP-2, - 5, and -7 in glioblastoma tumors. In order to establish a role for all the IGFBP isoforms in the progression and prognosis of astrocytoma, we analyzed the gene expressions of IGFBP-1 to –5, -7 to -10, and -L1 by real-time quantitative polymerase chain reaction (RT-PCR) and IGFBP-2, -3, -4, -5, and -7 by immunohistochemistry (IHC) in a cohort of 50 diffusely infiltrating astrocytoma tissues. There were greater than two-fold upregulations in the transcript levels of IGFBP-2, -3, and -4 and in the majority of glioblastomas (GBM) relative to anaplastic astrocytomas (AA). On the other hand, IGFBP-5 and -7 were upregulated in the majority of malignant astrocytomas (AA and GBM). In contrast to these observations, IGFBP-9 transcript levels were found to be downregulated in both AA and GBM tumors. Overexpression of IGFBP -2, -3, -4, –5, and -7 was observed by IHC maximally in the tumor cells of GBM. Notably, we found that in an independent set of GBM patients, expression of IGFBP-2 alone and coexpression of IGFBP-2 and -5 in the tumor were indicative of shorter survival. In addition, when IGFBP-3 coexpressed with epidermal growth factor receptor, it indicated shorter patient survival. Our study suggested associations between IGFBP-2, -3, -4, -5, and -7 and malignant transformation in diffusely infiltrating astrocytomas, with maximal expression in GBM. We also showed that overexpression of IGFBP-2, -3, and -5 isoforms portended poor prognosis in GBM patients.