Anil Sehgal

CXCR-4, a chemokine receptor, is overexpressed in and required for proliferation of glioblastoma tumor cells

Using the technique of differential hybridization of AtlasTM Human cDNA expression arrays, we previously reported the isolation of a G protein coupled receptor, CXCR‐4, which is overexpressed in glioblastoma multiforme tumor tissue (GMTT) compared to normal brain tissue (NBT).

Reduced Connexin43 expression in high-grade human brain glioma cells

Connexin43 (cx43), a gap junction protein, is implicated in the suppression of tumor cell growth. Numerous cancer cells show a reduction or loss of cx43 expression compared to their normal counterparts. Our previous studies suggest that cx43 expression is decreased in a variety of human brain tumor cell lines. To further investigate the role of cx43 in the development of human gliomas, we performed the present study on human glioma grades I–IV.

Molecular characterization of CXCR-4: a potential brain tumor-associated gene.

We have previously reported the isolation of a G protein‐coupled receptor, CXCR–4, that is overexpressed in glioblastoma multiforme tumor tissue (GMTT), as compared to normal brain tissue (NBT).

Application of the differential hybridization of Atlas Human expression arrays technique in the identification of differentially expressed genes in human glioblastoma multiforme tumor tissue.

Background and Objectives: Several molecular biology techniques are utilized to study changes in gene expression during the genesis of human tumors. Our objective was to identify genes that showed altered expression between normal brain tissue (NBT) and glioblastoma multiforme tumor tissue (GMTT).

Cell adhesion molecule Nr-CAM is over-expressed in human brain tumors

Using the technique of differential display‐polymerase chain reaction (DD‐PCR), we isolated a cDNA fragment that is over‐expressed in glioblastoma multiforme tissue as compared to normal brain tissue. Sequence analysis indicated that this sequence is identical to the previously isolated human neuron‐glia‐related cell adhesion molecule hNr‐CAM. Gene‐specific RT‐PCR analysis indicated that hNr‐CAM is over‐expressed in high‐grade astrocytomas, gliomas and glioblastoma tumor tissues as compared to normal brain tissue. High levels of hNr‐CAM expression also were observed in cell lines derived from astrocytomas, gliomas and glioblastoma multiforme tumors. Low levels of hNr‐CAM expression were observed in neuroblastoma, meningiomas, melanoma, normal breast and prostate tumor tissues. Northern blot analysis showed an alternatively spliced mRNA of 1.4 kb in several tumors as compared to the 7.5 kb transcript found in normal brain tissue. Genomic Southern blot analysis of DNA from 3 brain tumor cell lines showed that over‐expression of hNr‐CAM in brain tumors was not due to gene amplification. In situ hybridization analysis indicated that 11 of the 20 human brain tumor samples studied showed hNr‐CAM over‐expression. Our results suggest that hNr‐CAM is over‐expressed in malignant brain tumors and can serve as a novel marker for brain tumor detection and perhaps therapy. Int. J. Cancer 76:451–458, 1998.© 1998 Wiley‐Liss, Inc.

Isolation and characterization of a novel gene from human glioblastoma multiforme tumor tissue.

Using the technique of DD‐PCR (differential display‐polymerase chain reaction) we isolated a novel gene (D2‐2) that is overexpressed in glioblastoma multiforme tissue (GMT) as compared to normal brain tissue (NBT). D2‐2 is also highly expressed in recurrent glioma, colon tumor metastatic to brain, breast tumors, prostate tumors and a prostate tumor cell line (LNCaP). Northern blot analysis showed that D2‐2 is highly expressed in several tumor cell lines (MOLT lymphoblastic leukemia, SW480 colorectal adrenocarcinoma, A549 lung carcinoma, HL‐60 promyelocytic leukemia, 53 HeLa cells, K‐562 chronic myelogeneous leukemia and G361 melanoma) as compared to NBT. Additionally, D2‐2 is very highly expressed in cell lines derived from glioblastomas, grade IV astrocytomas, normal human fetal astrocytes (NHFA) and glioma. D2‐2 is moderately expressed in neuroblastoma, neuroectodermal and medulloblastoma tumor cell lines. D2‐2 expression is localized to the frontal lobe, occipital lobe and the cerebellum in the normal brain. Normal tissues such as thyroid, stomach, adrenal cortex, small intestine and pancreas show high expression of D2‐2. We also show that D2‐2 is expressed 28‐fold higher in fetal brain (20 weeks) than in adult brain. Sequence analysis of a 2.0‐kb fragment for D2‐2 shows no homology to known sequences in the data base. Int. J. Cancer 71:565‐572, 1997.

Characterization of C4-2 as a tumor-suppressor gene in human brain tumors

Brain tumors claimed the lives of 13,300 people in 1995. Our objective was to isolate and characterize unique tumor‐suppressor genes from human brain tumors derived from patients in the United States.

Expression and purification of prostate-specific membrane antigen in the baculovirus expression system and recognition by prostate-specific membrane antigen-specific T cells

Antigen-specific immunotherapy of cancer depends on a consistent source of well-defined protein antigen. Production of recombinant protein offers the obvious solution to this problem but few comparisons of recombinant and native proteins in cellular immune assays have been reported. We report expression of a putative immunotherapy antigen, prostate-specific membrane antigen (PSMA), in insect cells using a baculovirus vector. T cells stimulated with recombinant PSMA or native PSMA derived from the LNCaP cell line recognized both native PSMA and recombinant, baculoviral PSMA. These data indicate that PSMA produced in Sf9 cells is immunologically cross-reactive with native PSMA and therefore suitable for immunotherapy as it is recognized by both cellular and humoral immune responses.

Cloning, sequence, and developmental expression analysis of C4-2, a potential brain tumor-suppressor gene

Previously, we reported the isolation of C4‐2 as a potential tumor suppressor gene in human brain tumors. To understand the function of this gene, we investigated its molecular characterization and expression during development.