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ABSTRACT: Immunization with whole cells has been used extensively to generate monoclonal antibodies, produce protective immune responses, and discover new disease antigens. While glycans are abundant on cell surfaces, anti-glycan immune responses have not been well-characterized. We used glycan microarrays to profile 49 tumor-binding monoclonal antibodies generated by immunizing mice with whole cancer cells. A substantial proportion (41%) of the tumor binding antibodies bound carbohydrate antigens. The antibodies primarily recognize a group of 5 glycan antigens: Sialyl Lewis A (SLeA), Lewis A (LeA), Lewis X (LeX), blood group A (BG-A), and blood group H on a type 2 chain (BG-H2). The results have important implications for monoclonal antibody production and cancer vaccine development.
Bioorganic & medicinal chemistry letters 09/2012; 22(22):6839-43. · 2.65 Impact Factor
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ABSTRACT: The functions of the precursor H antigen for ABO blood group antigens are still not fully understood, particularly in cancer cells. In this study, we used hybridoma technology and NSY human colon cancer cells as an immunogen to generate a monoclonal antibody designated as MAb L9E10. The binding antigen of MAb L9E10 was identified as blood group (BG) H2 antigen using carbohydrate array and erythrocyte agglutination assays. In immunofluorescence study, we found that BG-H2 was expressed on the surfaces of both colon cancer stem cells and their differentiated progeny. In a functional study, we observed that MAb L9E10 inhibited tumor cell migration and invasion at a concentration of 10 microg/mL in vitro. This result suggests that MAb L9E10 could be used to study cancer biology, particularly cancer stem cell biology. In addition, it is potentially useful for studying gastric diseases caused by Helicobacter pylori bacteria, with attachment to human gastric epithelial cells mediated by blood group antigens Lewis b and H2. Finally, MAb L9E10 is an ideal biological reagent for identifying Bombay blood type in which erythrocytes have no BG-H2 antigen expression.
Hybridoma (2005) 08/2010; 29(4):355-9. · 0.42 Impact Factor
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ABSTRACT: Recently, cancer stem cells (CSC), undifferentiated cancer progenitor cells, have been successfully isolated from colorectal tumors. Targeting both CSCs and differentiated, rapidly proliferating tumor cells with therapeutic drugs provides a focused strategy to treat cancer. In this study, we isolated the monoclonal antibody (mAb) CC188 and characterized the epitope recognized by mAb CC188, which is useful for developing biological reagents that target CSCs.
We used a hybridoma technique to generate mAbs and an immunomagnetic method to isolate colon CSCs. We characterized mAb CC188 binding epitope and examined the epitope distribution in normal and tumor tissues, particularly in CSCs using tissue arrays and immunofluorescence staining method. We also evaluated the effect of mAb CC188 on invasiveness of NSY tumor cells.
mAb CC188 was generated and 98.9% (187 of 189 cases) of colon cancer were positively stained by mAb CC188. "+", "++," and "+++" staining were 25.9%, 28.6%, and 43.4%, respectively. The mAb CC188 binding epitope was identified as a carbohydrate, which was expressed on the surface of colon CSCs (CD133+), differentiated colon cancer cells (CD133-), and cells from various types of epithelial tumors. In contrast, the expression of the carbohydrate epitope was low in normal prostate muscle and pancreatic acinar cells, as well as in some normal epithelial cells of the breast duct, cervix, and skin. A functional study indicated that mAb CC188 suppressed the invasiveness of NSY tumor cells.
mAb CC188 selectively targets a carbohydrate epitope expressed on cancer cells, providing a viable method for specific tumor imaging and targeted therapy.
Clinical Cancer Research 12/2008; 14(22):7461-9. · 7.74 Impact Factor
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Robert J Myerson,
Anurag K Singh,
Heather M Bigott,
Bibiana Cha,
John A Engelbach,
Joonyoung Kim,
Wayne T Lamoreaux,
Eduardo Moros,
Petr Novak,
Terry L Sharp,
William Straube,
Michael J Welch, Mai Xu
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ABSTRACT: Mild hyperthermia can improve tumour oxygenation and enhance radiosensitivity. Imaging the hypoxic fraction of a tumour can guide hyperthermia treatment planning and facilitate treatment optimization. 64Cu-ATSM (Copper-diacetyl-bis(N4-methylthiosemicarbazone)) is a positron emitting compound that has been demonstrated to have rapid uptake and selective retention in hypoxic cells and has been used for imaging human and animal tumours. The purpose of the present report is to establish methodology that will allow one to use Cu-ATSM PET scanning to detect the impact of hyperthermia on tumour physiology in as little time as possible.
EMT6 tumours (mouse mammary carcinoma) were implanted into the subcutaneous tissue of both thighs of 10 BALB/c mice (one heated, one control tumour per animal). The target thermal dose was 41.5 degrees C x 45 min. Without interrupting heating, 64Cu-ATSM (mean activity 1.8 mCi) was then injected and serial PET scans were obtained. In a sub-group of four animals, a low administered activity (approximately 0.3 mCi) 64Cu-ATSM scan was also conducted before heating to permit a direct comparison of the effects of hyperthermia on the same tumours. In another sub-group of five animals, a low activity (approximately 0.3 mCi) 64Cu-PTSM (pyruvaldehyde-bis(N*-methylthiosemicarbazone)) scan was conducted before heating, to confirm a posited correlation between perfusion and early 64Cu-ATSM uptake.
This study corrected for perfusion differences by dividing tumour uptake by the average early (first minute) uptake ('self-normalized uptake'). The 10 heated tumours showed a significantly (p = 0.007) lower self-normalized uptake than control tumours by 2 min. For the four mice with low activity Cu-ATSM scans performed before hyperthermia, the tumours to be heated demonstrated self-normalized uptake consistent with the unheated control tumours and which departed significantly (p < or = 0.02) from their post-hyperthermia scans by 5 min. Comparisons between scans and needle electrode surveys were performed in an additional four animals with eight tumours. For technical reasons electrode surveys were done after the end of hyperthermia-and, therefore, these animals also had comparison scans taken after hyperthermia. Reduced self-normalized uptake on scans was associated with increased pO2 on electrode surveys. These data also suggested a substantial degradation of the effect on tumour hypoxia by approximately 15-45 min after the end of mild hyperthermia.
Short imaging times of approximately 5 min with modest (approximately 4-10) numbers of mice can discriminate the effects of mild hyperthermia on tumour physiology. The long-term objective is to use this tool to identify as short and mild a hyperthermia session as possible.
International Journal of Hyperthermia 03/2006; 22(2):93-115. · 1.92 Impact Factor
