ABSTRACT
BACKGROUND: Glypican-3 (GPC3) is a heparan sulfate proteoglycan. When it is disrupted, it causes the X-linked gigantism-overgrowth Simpson-Golabi-Behmel syndrome. Its involvement in growth control is consistent with recent reports that it can bind to growth factors, possibly including insulin-like growth factor 2. Further, it has been hypothesized that it may function as a tumor suppressor gene in breast and ovarian carcinomas and mesotheliomas. PATIENTS AND METHODS: RNA and protein were extracted from Wilms tumor and hepatoblastoma tissue samples and GPC3 levels were measured in these extracts by Northern blotting, reverse transcription polymerase chain reaction, and immunoblotting. RESULTS: In contrast to published results with carcinomas, high levels of GPC3 expression were found in Wilms tumor and hepatoblastoma. Low or undetectable expressions of this gene were found in normal tissue surrounding the tumor. CONCLUSIONS: Increased expression of GPC3 in Wilms tumor and hepatoblastoma suggests a growth-promoting or neutral activity for this gene product rather than a growth-suppressive effect.
Subject(s)
Heparan Sulfate Proteoglycans/genetics , Hepatoblastoma/genetics , Kidney Neoplasms/genetics , Liver Neoplasms/genetics , Wilms Tumor/genetics , Adolescent , Blotting, Western , Child , Child, Preschool , DNA Primers/chemistry , Female , Glypicans , Heparan Sulfate Proteoglycans/metabolism , Hepatoblastoma/metabolism , Humans , Infant , Kidney Neoplasms/metabolism , Liver Neoplasms/metabolism , Male , Neoplasm Proteins/metabolism , Neoplasm Staging , RNA, Messenger/analysis , RNA, Neoplasm/analysis , Reverse Transcriptase Polymerase Chain Reaction , Wilms Tumor/metabolismABSTRACT
Global human immunodeficiency virus type 1 (HIV-1) diversity may require engineering vaccines to express antigens representing strains prevalent in the target population of vaccine testing. The majority (90%) of incident infections in Thailand are genetic subtype E, with a small percentage of subtype B infections in the intravenous drug user populations. We have evaluated and compared the binding and HIV-1 neutralizing properties of serum antibodies induced in baboons by CHO cell-expressed monomeric gp120 derived from a CCR5-using (R5) subtype E primary HIV-1CM235 or a CXCR4-using (X4) subtype B T-cell line-adapted (TCLA) HIV-1SF2 isolate. In contrast to the subtype-specific HIV-1 neutralizing antibodies induced with recombinant HIV-1SF2 gp120 (rgp120SF2), rgp120CM235 immunization induced antibodies capable of neutralizing both subtype E and subtype B TCLA HIV-1 isolates. However, neither immunogen induced antibodies capable of neutralizing primary HIV-1 isolates. Antibody induced by rgp120CM235 preferentially bound natively folded gp120 and retained strong cross-reactivity against multiple gp120 strains within subtype E as well as subtype B. In contrast, antibody responses to rgp120SF2 were directed predominantly to linear epitopes poorly exposed on native gp120 and had more limited cross-recognition of divergent gp120. Fine epitope mapping revealed differences in antibody specificities. While both rgp120CM235 and rgp120SF2 induced antibodies to regions within C1, V1/V2, V3, and C5, unique responses were induced by rgp120CM235 to multiple epitopes within C2 and by rgp120SF2 to multiple epitopes within C3, V4, and C4. These data demonstrate that strain and/or phenotypic differences of HIV-1 subunit gp120 immunogens can substantially alter antibody binding specificities and subsequent HIV-1 neutralizing capacity.
