TAG-72 Research Articles

Comparing two TAG-72 binding peptides previously identified by phage display as potential imaging agents

To evaluate the targeting property in vitro and in vivo of two tumor-associated glycoprotein 72 (TAG-72) binding peptides, previously identified in this laboratory by phage selection using different elution conditions. The peptides GGVSCMQTSPVCENNL (A2-6) and NPGTCKDKWEICLLNGG (A3-10) were radiolabeled with technetium-99m ((99m)Tc) using N-hydroxysuccinimidyl-S-acetyl-mercaptoacetyltriglycine (NHS-MAG(3)) as a chelator or were biotinylated. The specificity of the two peptides for the TAG-72 positive LS-174T cancer cells was demonstrated in vitro both by flow cytometry analysis using the biotinylated peptides and by competitive binding using the (99m)Tc-labeled peptides. The in-vivo biodistributions of the peptides were evaluated in TAG-72 positive LS-174T tumor-bearing mice by small-animal single photon emission computed tomography/computed tomography imaging. As evidence of specific binding, both peptides showed a significant increase in percentage binding with increasing peptide concentration by flow cytometry analysis to LS-174T cells, but not to TAG-72 negative HT-29 cells. The (99m)Tc-labeled A2-6 peptide bound LS-174T cells with an inhibition constant at 50% of 46.5 nmol/l compared with 420 nmol/l for the A3-10 peptide. In mice, accumulation of both peptides was highest in kidneys and gallbladder. Tumors were clearly visible by single photon emission computed tomography imaging for both (99m)Tc-labeled peptides through 60 min, although the tumor accumulation was higher for the A3-10 peptide. The A3-10 peptide, with lower, yet reasonable binding affinity compared with the A2-6 peptide, showed sufficiently favorable specific binding and tumor accumulation to be considered further as a potential imaging agent for TAG-72 positive cancers.

A preliminary study on the expression of tumor-associated glycoprotein-72 in human gliomas

Tumor-associated glycoprotein-72 (TAG-72) is a high molecular weight tumor-associated glycoprotein, which is known to be overexpressed in various human tumors, but its expression in glioma tissues is unknown. Therefore, the aim of this study was to investigate whether TAG-72 is present in glioma and to evaluate the correlation between TAG-72 expression and the severity of the malignancy of this tumor. Immunohistochemistry and Western blot were used to investigate the expression of TAG-72 protein, respectively, in 152 patients with gliomas. There were 90 men and 62 women (mean age 50.6 ± 11.8 years). Astrocytoma was found in 130 patients and glioblastoma in 22. No TAG-72 expression was found in the non-cancerous brain tissues. TAG-72 protein expression was identified in 80 patients with glioma (52.6%). The expression level of TAG-72 protein was increased from gliomas with low grades to those with high grades. The highest mean value of TAG-72 protein was found in patients with glioblastoma (P < 0.01), whereas the lowest mean values were found in those with grade I astrocytoma (P < 0.01). Our results provide convincing evidence for the first time that the expression of TAG-72 is up-regulated in human gliomas. The expression levels of TAG-72 in gliomas were associated with the severity of the tumor. Whether positive TAG-72 protein expression can be used as a predictor for prognosis of the patients or as a therapeutic target for glioma requires further investigation.

Antigen-Directed Cancer Surgery for Primary Colorectal Cancer: 15-Year Survival Analysis

Tumor-associated glycoprotein-72 (TAG-72) is a mucin-like high-molecular-weight glycosylated protein complex overexpressed by many adenocarcinomas. Antigen-directed cancer surgery using radiolabeled anti-TAG-72 murine monoclonal antibodies (muMAbs) has been previously investigated for colorectal cancer. Survival analysis of primary colorectal cancer patients with a minimum of 15-year follow-up after antigen-directed cancer surgery was performed to assess the impact of complete surgical resection of all detectable radiolabeled anti-TAG-72 muMAb. Survival analysis was performed on 92 patients (study group) with primary colorectal cancer (July 1990 to August 1995) treated with antigen-directed cancer surgery using (125)I-labeled anti-TAG-72 muMAb. The study group was subdivided into those with no detectable TAG-72 antigen-bearing tissues (TAG-72 negative, N=33) and those with persistent detectable TAG-72 antigen-bearing tissues (TAG-72 positive, N=59) at completion of surgery. Comparisons were made with a control group (546 patients) from the same time period. Study group and control group were demographically similar, as were TAG-72-negative subgroup and TAG-72-positive subgroup. TAG-72-negative subgroup had significantly improved median survival (8.8 versus 2.5 years; P=0.005) and time-dependent survival (45.4% versus 22.0% at 10 years; P=0.002 and 39.4% versus 20.3% at 15 years; P=0.003) compared with TAG-72-positive subgroup. TAG-72 positivity was as an independent predictor of long-term mortality risk, when controlled for pathologic stage of disease. Absence of detectable TAG-72 antigen within the surgical field at completion of antigen-directed cancer surgery for primary colorectal cancer is of significant prognostic value, conferring a long-term survival advantage to those in whom complete surgical removal of all tissues with detectable radiolabeled anti-TAG-72 muMAb was accomplished.

An update on TroVax&amp;reg; for the treatment of progressive castration-resistant prostate cancer

Prostate cancer is a common human malignancy with few effective therapeutic options for treating advanced castration-resistant disease. The potential therapeutic effectiveness of immunotherapy and vaccines, in particular, has gained popularity based on the identification of prostate-associated antigens, potent expression vectors for vaccination, and data from recent clinical trials. A modified vaccinia Ankara (MVA) virus expressing 5T4, a tumor-associated glycoprotein, has shown promise in preclinical studies and clinical trials in patients with colorectal and renal cell carcinoma. This review will discuss the rationale for immunotherapy in prostate cancer and describe preclinical and limited clinical data in prostate cancer for the MVA-5T4 (TroVax®) vaccine.

Towards a Fully Synthetic MUC1‐Based Anticancer Vaccine: Efficient Conjugation of Glycopeptides with Mono‐, Di‐, and Tetravalent Lipopeptides Using Click Chemistry

The membrane-bound tumor-associated glycoprotein MUC1 is aberrantly glycosylated in cancer cells compared with normal cells, and is therefore considered an attractive target for cancer immunotherapy. However, tumor-associated glycopeptides from MUC1 do not elicit a sufficiently robust immune response. Therefore, antitumor vaccines were developed, which consist of MUC1 glycopeptides as the B epitopes and immune-stimulating toll-like receptor 2 (TLR 2) lipopeptide ligands. These fully synthetic vaccine candidates were prepared by solid-phase synthesis of the MUC1 glycopeptides. The Pam(3) Cys lipopeptide, also synthesized on solid-phase, was C-terminally coupled to oligovalent lysine cores, which N-terminally incorporate O-propargyl oligoethylene glycol acyl side chains. The MUC1 glycopeptides and lipopeptide lysine constructs were then conjugated by click chemistry to give oligovalent synthetic vaccines. Oligovalent glycopeptide-lipopeptide conjugates are considered more immunogenic than their monovalent analogues.

A Novel Tumor-Associated Pancreatic Glycoprotein Is Internalized by Human Dendritic Cells and Induces Their Maturation

Aberrant glycosylation or overexpression of cell-surface glycosylated tumor-associated Ags (TAA) distinguish neoplastic from normal cells. Interactions of TAA MUC1 and HER2/neu with dendritic cells (DC) preclude efficient processing, which impairs immune responses. It is thus important to define the mechanisms of interactions between DC and glycosylated TAA and their trafficking and processing for further T cell activation. In this work, we study interactions between DC and the oncofetal fucose-rich glycovariants of bile salt-dependent lipase (BSDL), expressed in pancreatic cancer tissues and referred to as pathological BSDL carrying the fucosylated J28 glycotope (pBSDL-J28) because it is characterized by the mAb J28. The expression of pBSDL-J28 was assessed by immunohistochemistry and quantified by confocal microscopy. Nontumoral pancreatic tissues and cells do not express pBSDL-J28. Using multidisciplinary approaches and functional studies, we provide the first evidence, to our knowledge, that this tumoral glycoprotein is rapidly internalized by human DC through macropinocytosis and endocytosis via mannose receptors and then transported to late endosomes for processing. Interestingly, pBSDL-J28 per se induced DC maturation with increased expression of costimulatory and CD83 molecules associated with cytokine secretion (IL-8 and IL-6). Surprisingly, DC retained their full ability to internalize Ags, making this maturation atypical. Finally, the allogeneic pBSDL-J28-treated DC stimulated lymphocyte proliferation. Besides, pulsing DC with pBSDL-J28 C-terminal glycopolypeptide and maturation with CD40L triggered CD4(+) and CD8(+) T cell proliferation. Therefore, interactions of pBSDL-J28, expressed on tumoral pancreatic tissue, with DC may lead to adequate Ag trafficking and processing and result in T cell activation.

The tumour-associated glycoprotein podoplanin is expressed in fibroblast-like synoviocytes of the hyperplastic synovial lining layer in rheumatoid arthritis

IntroductionActivated fibroblast-like synoviocytes (FLSs) in rheumatoid arthritis (RA) share many characteristics with tumour cells and are key mediators of synovial tissue transformation and joint destruction. The glycoprotein podoplanin is upregulated in the invasive front of several human cancers and has been associated with epithelial-mesenchymal transition, increased cell migration and tissue invasion. The aim of this study was to investigate whether podoplanin is expressed in areas of synovial transformation in RA and especially in promigratory RA-FLS.MethodsPodoplanin expression in human synovial tissue from 18 RA patients and nine osteoarthritis (OA) patients was assessed by immunohistochemistry and confirmed by Western blot analysis. The expression was related to markers of synoviocytes and myofibroblasts detected by using confocal immunofluoresence microscopy. Expression of podoplanin, with or without the addition of proinflammatory cytokines and growth factors, in primary human FLS was evaluated by using flow cytometry.ResultsPodoplanin was highly expressed in cadherin-11-positive cells throughout the synovial lining layer in RA. The expression was most pronounced in areas with lining layer hyperplasia and high matrix metalloproteinase 9 expression, where it coincided with upregulation of α-smooth muscle actin (α-sma). The synovium in OA was predominantly podoplanin-negative. Podoplanin was expressed in 50% of cultured primary FLSs, and the expression was increased by interleukin 1β, tumour necrosis factor α and transforming growth factor β receptor 1.ConclusionsHere we show that podoplanin is highly expressed in FLSs of the invading synovial tissue in RA. The concomitant upregulation of α-sma and podoplanin in a subpopulation of FLSs indicates a myofibroblast phenotype. Proinflammatory mediators increased the podoplanin expression in cultured RA-FLS. We conclude that podoplanin might be involved in the synovial tissue transformation and increased migratory potential of activated FLSs in RA.

Biodistribution and Dosimetry of In-111/Y-90-HuCC49ΔCh2 (IDEC-159) in Patients with Metastatic Colorectal Adenocarcinoma

CC49, an antibody (mAb) reactive to tumor-associated glycoprotein (TAG-72), has been extensively studied for radioimmunotherapy for colon cancer. Myelotoxicity has been dose-limiting because of prolonged circulation time in the plasma, and human anti-mouse antibody responses were observed in the majority of patients. A CH2 domain deleted and humanized CC49 (HuCC49ΔCh2) was developed to ameliorate these problems. This study reports biodistribution and dosimetry of (111)In/(90)Y-HuCC49ΔCh2 (IDEC-159). Five (5) patients with colon cancer were enrolled. Each patient received intravenous administration of 185 MBq (111)In-HuCC49ΔCh2, followed by sequential gamma camera imaging, and blood counting. Uptakes and clearance half-lives for organs and tumors were quantified from images. Absorbed doses for (90)Y-HuCC49ΔCh2 were derived from (111)In-HuCC49ΔCh2 kinetic data. Compared to reported (111)In/(90)Y-CC49 data in the literature, median blood circulation T(1/2β) was less at 38 (31-43) hours for (90)Y-HuCC49ΔCh2, than 50 hours for (90)Y-CC49. Median tumor-to-marrow absorbed dose ratio was 18 for (90)Y-HuCC49ΔCh2, and 9.53 for (90)Y-CC49. Median tumor-to-liver absorbed dose ratio was 3.14 for (90)Y-HuCC49ΔCh2, and 1.0 for (90)Y-CC49. Median tumor-to-spleen absorbed dose was 3.19 for (90)Y-HuCC49ΔCh2, and 1.07 for (90)Y-CC49. A humanized and CH2 domain-deleted CC49 antibody radiolabeled with (111)In/(90)Y showed improved tumor-to-normal dose ratios over those reported from studies with intact CC49.

Immunoregulatory effects of AFP domains on monocyte-derived dendritic cell function

BackgroundAlpha-fetoprotein (AFP) is a tumor-associated glycoprotein that functions in regulation of both ontogenic and oncogenic growth. Recent study showed that AFP can induce apoptosis or impair monocyte-derived dendritic cell (MDDC) function. However, it is still unclear which AFP domain (D-AFP) plays major role in this function.ResultsAs expected monocytes cultured in the presence of Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF) and Interleukin-4 (IL-4) developed into MDDC. Up-regulation of HLA-DR and CD11c as well as loss of CD14 molecules could be observed. Full length AFP (FL-AFP), domain 2 AFP (D2-AFP) and D3-AFP, but not D1-AFP, significantly inhibited the expression of HLA-DRhigh/CD11chigh and CD80+/CD86high molecules. In contrast, CD83 expression was substantially down-regulated in all samples. Expression of CD40 was significantly suppressed by FL-AFP but not by any D-AFPs. Finally, both FL-AFP and D-AFP impaired the MDDC ability to secrete IL-12 (p70).ConclusionsD2- and D3- but not D1-AFP extensively suppresses the MDDC function. All the recombinant AFP proteins impaired the ability of MDDC to secrete IL-12.

Phase I Trial of TGF-β2 Antisense GM-CSF Gene-Modified Autologous Tumor Cell (TAG) Vaccine

On the basis of the hypothesis that the combined expression of immunostimulatory granulocyte macrophage colony stimulating factor (GM-CSF) and antitumor suppressor TGF-β2 antisense (AS) transgenes can break tolerance and stimulate immune responses to cancer-associated antigens, we constructed an expression plasmid [the tumor-associated glycoprotein (TAG) plasmid] that coexpresses GM-CSF and TGF-β2 AS nucleotide sequences and which was incorporated into an autologous whole-cell vaccine. Patients undergoing resection were enrolled. Freshly harvested autologous tumor cells were mechanically and enzymatically disaggregated, then electroporated with the TAG vector. The resulting vaccine was irradiated, then aliquoted and cryopreserved until the time of injection. Patients received a minimum of 5 to a maximum of 12 monthly intradermal injections. Immune function was monitored at baseline and at months 3 and 6. Vaccine manufacturing efficiency was 84% (32/38). Twenty-three patients received at least 1 vaccination. There were no grade 3 or 4 toxicities, and grade 1 and 2 events were local in nature. Seventeen of 21 patients had stable disease (SD) at month 2 or later as their best response, and 1 patient with stage IVa malignant melanoma achieved a complete response (CR) following 11 vaccinations and remains without evidence of disease 2 years following initiation of therapy. Six of 13 patients displayed a positive enzyme-linked immunospot (ELISPOT) response to autologous TAG vaccine at week 12 including 3 patients with prolonged SD or CR. The 3 other patients survived through week 24, as compared with none of the 7 ELISPOT-negative patients. On the basis of safety and clinical and immunologic results, further evaluation of bifunctional vaccines is warranted.

Identification of a high affinity TAG-72 binding peptide by phage display selection

Purpose: Phage display was used to select novel peptides that specifically bind the TAG-72 antigen and with properties suitable for imaging TAG-72 positive cancers. Results: After three rounds of selection against TAG-72 and using two different elution conditions including a long elution, the consensus sequences FRERCDKHPQKCTKFL and DPRHCQKRVLPCPAWL were expressed on phages G3-15 and T3-15 respectively. ELISA, fluorescence-activated cell sorting analysis and fluorescence microscopy provided evidence that both phages specifically bound TAG-72 in vitro. Both peptides are stable in 37oC serum. By a cell binding competition assay, the IC50 for T3-15 was measured as 0.29 nM and therefore 36-fold higher affinity than G3-15 at 10.32 nM. The biodistribution in mice carrying LS-174T tumors in one thigh were similar for both 99mTc-peptides at 30 min, but at 90 min the 99mTc-T3-15 peptide accumulated almost three times higher in the tumor. The SPECT/CT images were consistent with the biodistribution results. Procedures: The f88-4/Cys6 phage library and two different elution conditions were used to identify two new higher affinity binding peptides for the TAG-72 antigen. One, was a single brief elution with pH 2.2 glycine buffer, and the second began with the glycine elution but was followed with a longer elution with Tris buffered saline (TBS) at pH 7.4. The phages that bound TAG-72 were evaluated by fluorescence-activated cell sorting analysis using TAG-72 positive LS-174T cells and confirmed by immunofluorescence imaging. The consensus peptides displayed on the selected phages were synthesized and conjugated with NHS-MAG3 for radiolabeling with 99mTc. The IC50 for TAG-72 binding was evaluated by cell binding competition in vitro while binding affinity was evaluated in vivo by necropsy and SPECT/CT imaging in a tumor mouse model. Conclusion: We have identified a peptide with a sub nanomolar inhibition constant for the TAG-72 antigen that may have application in cancer imaging.

Tumor-associated glycoprotein (TAG-72) is a natural ligand for the C-type lectin-like domain that induces anti-inflammatory orientation of early pregnancy decidual CD1a+ dendritic cells

Tumor-associated glycoprotein-72 (TAG-72) is physiologically present in secretory phase endometrium, but its presence and possible immunological role in early normal human pregnancy decidua has not received attention. The double labeling of paraffin-embedded early pregnancy decidua sections using B-72.4 anti-TAG-72 mAb and MNF 116 anti-cytokeratin mAb revealed the absence of TAG-72 in uterine decidua of normal and pathological pregnancies (non-embryonic pregnancy and missed abortion) at the implantation sites, although it was present in epithelial cells at and away from the tubal implantation site of an ectopic pregnancy. TAG-72 binds and internalizes by reacting with the mannose receptor (MR-CD206) or with DC-specific ICAM reacting non-integrin (DC-SIGN-CD209) on decidual CD1a+ cells. Decidual CD1a+ cells stimulated with TAG-72 decreased CD83 expression and diminished IL-15 and IFN-γ intracellular production. TAG-72-treated CD1a+ cells decreased IFN-γ production in syngenic decidual and allogenic cord blood T cells even in the presence of lipopolysaccharide. TAG-72- and lipopolysaccharide-pre-treated CD1a+ cells significantly increased IL-4 expression in allogenic cord blood T cells. TAG-72 increased allogenic cord blood T cell proliferation, mediated by decidual CD1a+ cells, compared with its effect on the proliferation of syngenic decidual T cells. All these data emphasize the anti-inflammatory properties of TAG-72-treated decidual CD1a+ cells in terms of their interaction with T cells. Thus, the absence of TAG-72 at the maternal-fetal interface during early pregnancy could lead to a mild pro-inflammatory response that may be beneficial for pregnancy success and trophoblast growth control.

Polyelectrolyte nanogels decorated with monoclonal antibody for targeted drug delivery

Novel surface-functionalized cross-linked nanogels were developed as a platform to allow conjugation of monoclonal antibodies (mAb) for targeted drug delivery. Well-defined diblock copolymers of poly(ethylene glycol)- b-poly(methacrylic acid) (PEG- b-PMA) with PEG terminal aldehyde functionality were synthesized by atom transfer radical polymerization (ATRP) and characterized by GPC and 1H NMR. These copolymers were used to prepare nanogels via condensation of PEG- b-PMA with Ca 2+ ions into micelle-like aggregates, cross-linking of the PMA/Ca 2+ cores and removal of Ca 2+ ions. The resulting nanogels represent highly swollen spherical polyelectrolyte particles with free terminal aldehyde functionalities at the nonionic PEG chains. A reductive amination reaction between aldehyde groups and amino groups of mAb resulted in effective conjugation to the nanogels of mAb CC49 against tumor-associated glycoprotein 72 (TAG-72). The mAb retained the binding affinity to bovine submaxillary mucin after conjugation as shown by surface plasmon resonance (SPR). Therefore, aldehyde-functionalized nanogels can be linked to mAb using a simple, one-step approach. They may have potential for targeted delivery of diagnostic and therapeutic agents to tumors.

Biodistribution and Clearance of In-111/Y-90-IDEC-159 in Patients with Metastatic Colorectal Adenocarcinoma

CC49, an antibody(mAb) reactive to tumor-associated glycoprotein (TAG-72), has been extensively studied in targeted radionuclide therapy trials for colon cancers. Myelotoxicity has been the dose-limiting factor because of prolonged circulation time in plasma, and HAMA responses were observed in the majority patients. These two problems can be reduced by using a CH2 domain deleted and humanized mAb. This study evaluated biodistribution and pharmacokinetic of IDEC-159, a humanized and CH2 domain-deleted CC49 (HuCC49ΔCh2).

Regulation of NK-cell function by mucins via antigen-presenting cells

Decidual antigen-presenting cells including dendritic cells (DCs) and CD14(+) macrophages, as mediators of the first encounter with fetal antigens, appear to be critically involved in the initiation of primary immune response by regulating innate- and adaptive immunity. Interleukin-15, produced by them, permits the proliferation and differentiation of CD3(-)CD16(-)CD94(+)NKG2A(+)CD56(+bright) decidual NK cells that identify trophoblast cells. These cells are able to kill them after Th1 cytokine overstimulation and by increasing the release of preformed cytotoxic mediators. Thus, the local microenvironment is a potent modulator of antigen-presenting cell functions. Tumor associated glycoprotein-72 (TAG-72) and mucine 1 (MUC-1) are glycoproteins secreted by uterine epithelial cells. Our hypothesis is that TAG-72 and MUC-1 are the natural ligands for carbohydrate recognition domains (CRDs) of endocytic mannose receptor (MR or CD206) and DC-specific ICAM non-integrin (DC-SIGN or CD209) expressed on decidual CD14(+) macrophages and CD1a(+) DCs. They might be able to condition antigen-presenting cells to produce distinct profiles of cyto/chemokines with consequential reduction in NK-cell numbers and cytotoxic potential leading to insufficient control over trophoblast growth. This hypothesis could explain the disappearance of MUC-1 beneath the attached embryo during the process of successful implantation when tight regulation of trophoblast invasion is needed. As IL-15 is the earliest and the most important factor in NK-cell proliferation, differentiation, and maturation, we expected primarily an increase of IL-15 expression in antigen-presenting cells concomitant with the disappearance of mucins and the enhancement in NK cells numbers and of cytotoxic potential after their close contact with early pregnancy decidual antigen-presenting cells. If our hypothesis is correct, it would contribute to the understanding of the role of mucins in the redirection of immune response via antigen-presenting cells and could help explain the mechanism of IL-15 regulation at the maternal-fetal interface of normal, ectopic-, and pathological pregnancies with effects on NK-cell proliferation, cytolytic mediator expression, and regulation of trophoblast growth control.

124I-HuCC49deltaCH2 for TAG-72 antigen-directed positron emission tomography (PET) imaging of LS174T colon adenocarcinoma tumor implants in xenograft mice: preliminary results

Background18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) is widely used in diagnostic cancer imaging. However, the use of 18F-FDG in PET-based imaging is limited by its specificity and sensitivity. In contrast, anti-TAG (tumor associated glycoprotein)-72 monoclonal antibodies are highly specific for binding to a variety of adenocarcinomas, including colorectal cancer. The aim of this preliminary study was to evaluate a complimentary determining region (CDR)-grafted humanized CH2-domain-deleted anti-TAG-72 monoclonal antibody (HuCC49deltaCH2), radiolabeled with iodine-124 (124I), as an antigen-directed and cancer-specific targeting agent for PET-based imaging.MethodsHuCC49deltaCH2 was radiolabeled with 124I. Subcutaneous tumor implants of LS174T colon adenocarcinoma cells, which express TAG-72 antigen, were grown on athymic Nu/Nu nude mice as the xenograft model. Intravascular (i.v.) and intraperitoneal (i.p.) administration of 124I-HuCC49deltaCH2 was then evaluated in this xenograft mouse model at various time points from approximately 1 hour to 24 hours after injection using microPET imaging. This was compared to i.v. injection of 18F-FDG in the same xenograft mouse model using microPET imaging at 50 minutes after injection.ResultsAt approximately 1 hour after i.v. injection, 124I-HuCC49deltaCH2 was distributed within the systemic circulation, while at approximately 1 hour after i.p. injection, 124I-HuCC49deltaCH2 was distributed within the peritoneal cavity. At time points from 18 hours to 24 hours after i.v. and i.p. injection, 124I-HuCC49deltaCH2 demonstrated a significantly increased level of specific localization to LS174T tumor implants (p = 0.001) when compared to the 1 hour images. In contrast, approximately 50 minutes after i.v. injection, 18F-FDG failed to demonstrate any increased level of specific localization to a LS174T tumor implant, but showed the propensity toward more nonspecific uptake within the heart, Harderian glands of the bony orbits of the eyes, brown fat of the posterior neck, kidneys, and bladder.ConclusionsOn microPET imaging, 124I-HuCC49deltaCH2 demonstrates an increased level of specific localization to tumor implants of LS174T colon adenocarcinoma cells in the xenograft mouse model on delayed imaging, while 18F-FDG failed to demonstrate this. The antigen-directed and cancer-specific 124I-radiolabled anti-TAG-72 monoclonal antibody conjugate, 124I-HuCC49deltaCH2, holds future potential for use in human clinical trials for preoperative, intraoperative, and postoperative PET-based imaging strategies, including fused-modality PET-based imaging platforms.

Glycoprotein 90K, downregulated in advanced colorectal cancer tissues, interacts with CD9/CD82 and suppresses the Wnt/β-catenin signal via ISGylation of β-catenin

Background and aims90K, a tumour-associated glycoprotein, interacts with galectins and has roles in host defence by augmenting the immune response, but the serum 90K level was suggested to indicate poor...

Abstract 1471: Glycoprotein 90K suppresses Wnt signaling via ISGylation-dependent ubiquitination of β-catenin that needs interaction with CD9/CD82

Abstract Backgrounds: Previously, we have observed that a tumor-associated 90K glycoprotein plays a potential tumor suppressor role in colorectal cancer (CRC) cells via antagonizing the canonical Wnt signaling pathway, which is functionally masked via interaction with extracellular galectin. Here, we investigated the signaling pathways of 90K action on CRC cells and its expression in human CRC tissues. Results: We identify a novel pathway comprising a secretory 90K and a CD9/CD82 tetraspanin web; in this pathway, 90K interacts with CD9/CD82, suppresses the Wnt/β-catenin signal via a novel proteasomal-ubiquitination mechanism of β-catenin that is dependent of ISG15 modification (ISGylation). In colon tissues from stage IV human CRC and invading cancer cells of corresponding metastatic liver tissues, in which β-catenin and galectin expression was higher, immunostained 90K and CD9/CD82 were lower than in adjacent hepatic tissues or colon tissues from stage I. Conclusions: 90K itself has antitumor activity in CRC cells via suppression of Wnt signaling with a novel mechanism of ISGylation-dependent ubiquitination of β-catenin when it interacts with CD9/CD82, but is downregulated in advanced CRC tissues. Our data suggest a strategy of strengthening this novel pathway with concomitant knockdown of galectins as a potential therapeutic approach to CRC progression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1471.

Improved efficacy of α‐particle–targeted radiation therapy

Human epidermal growth factor receptor-2 (HER-2) and tumor-associated glycoprotein 72 (TAG-72) have proven to be excellent molecular targets for cancer imaging and therapy. Trastuzumab, which binds to HER-2, is effective in the treatment of disseminated intraperitoneal disease when labeled with (213)Bi or (212)Pb. (213)Bi-humanized CC49 monoclonal antibody (HuCC49DeltaCH2), which binds to TAG-72, inhibits the growth of subcutaneous xenografts. A next logical step to improve therapeutic benefit would be to target tumors with both molecules simultaneously. Athymic mice bearing intraperitoneal human colon carcinoma xenografts were treated with a combination of trastuzumab and HuCC49DeltaCH2 labeled with (213)Bi administered through an intraperitoneal route. The sequence of administration also was examined. Before combining the 2 monoclonal antibodies, the effective doses of (213)Bi-CC49DeltaCH2 and (213)Bi-trastuzumab for the treatment of peritoneal disease were determined to be 500 muCi for each labeled antibody. Treatment with (213)Bi-HuCC49DeltaCH2 resulted in a median survival of 45 days and was comparable to the median survival achieved with (213)Bi-trastuzumab. Each combination provided greater therapeutic efficacy than either of the agents given alone. However, the greatest therapeutic benefit was achieved when (213)Bi-HuCC49DeltaCH2 and (213)Bi-trastuzumab were coinjected, and a median survival of 147 days was obtained. Dual targeting of 2 distinct molecules in tumors such as TAG-72 and HER-2 with alpha-particle radiation resulted in an enhanced, additive, therapeutic benefit. The authors also observed that this radioimmunotherapeutic strategy was well tolerated.

Mucinous Eccrine Adenocarcinoma: Report of Six Cases

Mucinous eccrine adenocarcinoma may occur in the periocular region. Since the initial description of this tumor in 19521,2, there have been several individual case reports described. The lesion may be locally invasive and recur after incomplete excision, although it rarely metastasizes. The tumor is often clinically mistaken for other cutaneous lesions due to its variable appearance. After obtaining approval from the Emory University Institutional Review Board, we identified six cases with the pathologic diagnosis of mucinous eccrine carcinoma of the eyelid in the L.F. Montgomery Ophthalmic Pathology Laboratory, Emory University, Atlanta, Georgia. All cases had been diagnosed by an experienced ophthalmic pathologist (HEG). Demographic, clinical surgical, pathologic and follow-up information of the patients were reviewed. Hematoxylin and eosin and periodic acid-Schiff stained sections were examined in all cases. Immunohistochemical stains for cytokeratin 7 (CK7), epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), estrogren receptor (ER) and progesterone receptor (PR) in all cases and electron microscopic examination were performed in one representative case. A summary of the clinical findings is shown in Table 1. The tumor was more common in women then men and the mean age at presentation was 50 years (range 30–78). Thre cases occurred in the upper eyelid, two in the lower eyelid and one in the periocular tissue. The clinical description in most cases was that of a slow-growing lesion that arose over months to years. The lesions measured from 3×2 to 8×5 mm in diameter and most appeared as a solitary elevated nodule. Five patients underwent Mohs micrographic surgical removal of the tumor. Examination of the surgical margins of resection in four of those patients showed no evidence of tumor and all of those patients have remained tumor free with 3 months to 2 years follow-up. One of those patients had positive surgical margins of resection and had two recurrences which were surgically excised. The treatment and follow-up for one patient (case 2) was unavailable. Table 1 Clinical Characteristics of Mucinous Eccrine Carcinoma of the Eyelid The pathologic features of the tumor are illustrated by case 5 (Figs 1–3). In all cases included dermis infiltrated with nests of tumor cells floating in a sea of mucin demonstrated by alcian blue and colloidal iron stains. The tumor cells exhibited mildly pleomorphic, vesiculated nuclei, occasional prominent nucleoli and scanty, eosinophilic cytoplasm. Several tumors formed cysts lined by a proliferation of neoplastic cells exhibiting a papillary configurations or tubules with central lumens. Immunohistochemical stains were positive for CK7, EMA, CEA, ER, and PR in ?cases. Ultrastructural examination of case 5 showed a tumor composed of stratified cells with centrally placed, round to oval nuclei, marginated chromatin andvariable amounts of cytoplasm, forming glandular structures with lumens. These cells exhibited intercellular junctions, scattered mictochondria, glycogen granules and microvillae projecting toward the lumens of the glandular structures. Figure 1 The right lower eyelid of a patient with mucinous eccrine adenocarcinoma shows a slow-growing elevated nodule. Figure 3 A photomicrography shows a section of mucinous eccrine adenocarcinoma of eyelid stained with colloidal iron demonstrates the presence of mucin (original magnification ×25). There is controversy regarding whether mucinous eccrine carcinoma arrises in a sweat gland or apocrine gland.3 This tumor has been described to arise in the eyelid, mostly in individual case reports.4–9 When this tumor arises in the eyelid, it is usually a unilateral lesion, although bilateral cases have been reported.8 The tumor usually appears as a solitary, asymptomatic, slow-growing nodule, cyst or ulcer.6–8 The contour of the lesion may be elevated, pedunculated, or papillomatous and the surface may be smooth, irregular or crusted. The color of the lesion may be tan, grey, blue or brown. The lesion is usually less than 3mm in diameter, although a 20mm diameter tumor has been previously reported.8 Due to the variable clinical appearance, clinical diagnoses have included chalazion, epidermoid cyst, hemangioma, myxoma, lipoma, papilloma, keratoacanthoma, pyogenic granuloma, sebaceous cyst, sebaceous carcinoma, squamous cell carcinoma, basal cell carcinoma, adenoid cystic carcinoma, malignant melanoma and Kaposi sarcoma.9 Immunohichemical stains for mucinous eccrine carcinoma may be positive for cytokeratins (CK7, CAM5.2), carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), mucours-associated peptides of the trefoil factor family (TFF1 and 3), and tumor-associated glycoprotein (TAG-72).10,11 Characteristic electron microscopic features include dark cells at the periphery with mucin production and pale cells with little or no mucin production centrally placed in each nest of cells.12,13 Complete excision of this tumor is recommended, varying from excision with clinically visible margins to wide local excision.6,7 We recommend complete surgical excision with histologic confirmation of negative surgical margins of resection. This may be accomplished by Mohs micrographic surgery.14 There is no evidence that a sentinel lymph node biopsy is indicated for patients with mucinous eccrine carcinoma of the eyelid.