Govind Ragupathi

Memorial Sloan-Kettering Cancer Center, New York, New York, United States

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Publications (69)377.93 Total impact

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    ABSTRACT: Immunoadjuvants are used to potentiate the activity of modern subunit vaccines that are based on molecular antigens. An emerging approach involves the combination of multiple adjuvants in a single formulation to achieve optimal vaccine efficacy. Herein, to investigate such potential synergies, we synthesized novel adjuvant conjugates based on the saponin natural product QS-21 and the aldehyde tucaresol via chemoselective acylation of an amine at the terminus of the acyl chain domain in QS saponin variants. In a preclinical mouse vaccination model, these QS saponin-tucaresol conjugates induced antibody responses similar to or slightly higher than those generated with related QS saponin variants lacking the tucaresol motif. The conjugates retained potent adjuvant activity, low toxicity, and improved activity-toxicity profiles relative to QS-21 itself and induced IgG subclass profiles similar to those of QS-21, indicative of both Th1 cellular and Th2 humoral immune responses. This study opens the door to installation of other substituents at the terminus of the acyl chain domain to develop additional QS saponin conjugates with desirable immunologic properties.
    Bioorganic & Medicinal Chemistry 09/2014; 22(21). DOI:10.1016/j.bmc.2014.09.016 · 2.95 Impact Factor
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    ABSTRACT: Adjuvants are materials added to vaccines to enhance the immunological response to an antigen. QS-21 is a natural product adjuvant under investigation in numerous vaccine clinical trials, but its use is constrained by scarcity, toxicity, instability and an enigmatic molecular mechanism of action. Herein we describe the development of a minimal QS-21 analogue that decouples adjuvant activity from toxicity and provides a powerful platform for mechanistic investigations. We found that the entire branched trisaccharide domain of QS-21 is dispensable for adjuvant activity and that the C4-aldehyde substituent, previously proposed to bind covalently to an unknown cellular target, is also not required. Biodistribution studies revealed that active adjuvants were retained preferentially at the injection site and the nearest draining lymph nodes compared with the attenuated variants. Overall, these studies have yielded critical insights into saponin structure-function relationships, provided practical synthetic access to non-toxic adjuvants, and established a platform for detailed mechanistic studies.
    Nature Chemistry 07/2014; 6(7):635-43. DOI:10.1038/nchem.1963 · 23.30 Impact Factor
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    ABSTRACT: To report on a phase I trial designed to find the maximally tolerated dose in children of the immunologic adjuvant OPT-821 in a vaccine containing neuroblastoma-associated antigens (GD2 and GD3; NCT00911560). Secondary objectives were to obtain preliminary data on immune response and activity against minimal residual disease (MRD). Treatment also included the immunostimulant β-glucan.EXPERIMENTAL DESIGN: Patients with neuroblastoma in ≥2nd complete/very good partial remission received vaccine subcutaneously (weeks 1-2-3-8-20-32-52). Vaccine contained 30 μg each of GD2 and GD3 stabilized as lactones and conjugated to the immunologic carrier protein keyhole limpet hemocyanin; and OPT-821, which was dose escalated as 50, 75, 100, and 150 μg/m(2) per injection. Oral β-glucan (40 mg/kg/day, 14 days on/14 days off) started week 6.RESULTS: The study was completed with 15 patients because there was no dose-limiting toxicity at 150 μg/m(2) of OPT-821 (the dosing used in adults). Thirteen of fifteen patients received the entire protocol treatment, including 12 who remain relapse-free at 24+ to 39+ (median 32+) months and 1 who relapsed (single node) at 21 months. Relapse-free survival was 80% ± 10% at 24 months. Vaccine and β-glucan were well tolerated. Twelve of fifteen patients had antibody responses against GD2 and/or GD3. Disappearance of MRD was documented in 6 of 10 patients assessable for response.CONCLUSIONS: This immunotherapy program lacks major toxicity and is transportable to any outpatient clinic. Patient outcome is encouraging but the efficacy is uncertain because of the complexity and heterogeneity of prior therapies. A larger phase II trial is underway. Clin Cancer Res; 1-8. ©2014 AACR.
    Clinical Cancer Research 02/2014; 20(5). DOI:10.1158/1078-0432.CCR-13-1012 · 8.19 Impact Factor
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    ABSTRACT: Despite their considerable advantages, many circulating biomarkers have well-documented limitations. One prominent shortcoming in oncology is a high frequency of false-positive indications for malignant disease in upfront diagnosis. Because one common cause of false positivism is biomarker production from benign disorders in unrelated host tissues, we hypothesized that probing the sites of biomarker secretion with an imaging tool could be a broadly useful strategy to deconvolute the meaning of foreboding but inconclusive circulating biomarker levels. In preparation to address this hypothesis clinically, we developed (89)Zr-5B1, a fully human, antibody-based radiotracer targeting tumor-associated CA19.9 in the preclinical setting. (89)Zr-5B1 localized to multiple tumor models representing diseases with undetectable and supraphysiologic serum CA19.9 levels. Among these, (89)Zr-5B1 detected orthotopic models of pancreatic ductal adenocarcinoma, an elusive cancer for which the serum assay is measured in humans but with limited specificity in part because of the frequency of CA19.9 secretion from benign hepatic pathologies. In this report, a general strategy to supplement some of the shortcomings of otherwise highly useful circulating biomarkers with immunoPET is described. To expedite the clinical validation of this model, a human monoclonal antibody to CA19.9 (a highly visible but partially flawed serum biomarker for several cancers) was radiolabeled and evaluated, and the compelling preclinical evidence suggests that the radiotracer may enhance the fidelity of diagnosis and staging of pancreatic ductal adenocarcinoma, a notoriously occult cancer.
    Journal of Nuclear Medicine 09/2013; 54(11). DOI:10.2967/jnumed.113.119867 · 5.56 Impact Factor
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    ABSTRACT: We addressed the possibility that low levels of tumor cell bound antibodies targeting gangliosides might accelerate tumor-growth. To test this hypothesis, we treated mice with a range of mAb doses against GM2,GD2,GD3 and CD20 after challenge with tumors expressing these antigens and tested the activity of the same mAbs in-vitro and the mechanisms behind the complement-mediated tumor growth acceleration that we observed and an approach to overcome it. Serologically detectable levels of IgM-mAb against GM2 are able to delay or prevent tumor growth of high GM2-expressing-cell-lines both in-vitro and in a SCID mouse model, while very low levels of this mAb resulted in slight but consistent acceleration of tumor growth in both settings. Surprisingly, this is not restricted to IgM-antibodies targeting GM2 but consistent against IgG-mAb targeting GD3 as well. These findings were mirrored by in-vitro studies with antibodies against these antigens as well as GD2 and CD20 (Rituxan), and shown to be complement-dependent in all cases. Complement-mediated-accelerated-growth of cultured tumor cell-lines initiated by low mAb levels was associated with activation of the PI3K/AKT survival pathway and significantly elevated levels of both p-AKT and p-PRAS40. This complement-mediated PI3K-activation and accelerated tumor growth in-vitro and in-vivo are eliminated by PI3K-inhibitors NVP-BEZ235 and Wortmannin which also significantly increased efficacy of high doses of these 4 mAbs. Our findings suggest that manipulation of the PI3K/AKT pathway and its signaling network can significantly increase the potency of passively administered mAbs and vaccine-induced-antibodies targeting a variety of tumor-cell-surface-antigens.
    Clinical Cancer Research 07/2013; 19(17). DOI:10.1158/1078-0432.CCR-13-0088 · 8.19 Impact Factor
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    ABSTRACT: QS-21 is a potent immunostimulatory saponin that is currently under clinical investigation as an adjuvant in various vaccines to treat infectious diseases, cancers, and cognitive disorders. Herein, we report the design, synthesis, and preclinical evaluation of simplified QS-21 congeners to define key structural features that are critical for adjuvant activity. Truncation of the linear tetrasaccharide domain revealed that a trisaccharide variant is equipotent to QS-21, while the corresponding disaccharide and monosaccharide congeners are more toxic and less potent, respectively. Modification of the acyl chain domain in the trisaccharide series revealed that a terminal carboxylic acid is well-tolerated while a terminal amine results in reduced adjuvant activity. Acylation of the terminal amine can, in some cases, restore adjuvant activity and enables the synthesis of fluorescently labeled QS-21 variants. Cellular studies with these probes revealed that, contrary to conventional wisdom, the most highly adjuvant active of these fluorescently labeled saponins does not simply associate with the plasma membrane, but rather is internalized by dendritic cells.
    Journal of the American Chemical Society 08/2012; 134(32):13448-57. DOI:10.1021/ja305121q · 11.44 Impact Factor
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    ABSTRACT: Mucin glycoproteins present a complex structural landscape arising from the multiplicity of glycosylation patterns afforded by their numerous serine and threonine glycosylation sites, often in clusters, and with variations in respective glycans. To explore the structural complexities in such glycoconjugates, we used NMR to systematically analyze the conformational effects of glycosylation density within a cluster of sites. This allows correlation with molecular recognition through analysis of interactions between these and other glycopeptides, with antibodies, lectins, and sera, using a glycopeptide microarray. Selective antibody interactions with discrete conformational elements, reflecting aspects of the peptide and disposition of GalNAc residues, are observed. Our results help bridge the gap between conformational properties and molecular recognition of these molecules, with implications for their physiological roles. Features of the native mucin motifs impact their relative immunogenicity and are accurately encoded in the antibody binding site, with the conformational integrity being preserved in isolated glycopeptides, as reflected in the antibody binding profile to array components.
    ACS Chemical Biology 03/2012; 7(6):1031-9. DOI:10.1021/cb300076s · 5.44 Impact Factor
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    ABSTRACT: Polysialic acid (polySA) is a polymer side chain bound to the neural cell adhesion molecule that is extensively expressed on the surface of small cell lung cancer (SCLC) cells. In our previous study, a robust antibody response was noted in patients with SCLC after vaccination with 30 μg of keyhole limpet hemocyanin (KLH)-conjugated N-propionylated (NP-) polySA, but peripheral neuropathy and ataxia were detected in several vaccinated patients. The objectives of the current trial were to establish the lowest optimal dose and to confirm the safety of the induction of antibodies against polySA with the NP-polySA vaccine. Patients with SCLC who completed initial treatment and had no evidence of disease progression were injected with either 10 or 3 μg of NP-polySA conjugated to KLH and mixed with 100 μg of immunologic adjuvant (QS-21) at weeks 1, 2, 3, 4, 8, and 16. Nine patients were enrolled at each of the two dose levels. Prior to vaccination, one patient in each group had low-titer antibodies against polysialic acid. All patients at the 10 μg vaccine dose level responded to vaccination with IgM antibody titers against polysialic acid (median titer 1/1,280 by ELISA), and all but one patient made IgM and IgG antibodies against the artificial vaccine immunogen, NP-polysialic acid (median titer 1/10,240). The antibody responses at the 3 μg vaccine dose level were lower; six of nine patients developed antibodies against polysialic acid (median titer 1/160). Post-vaccination sera from 6/9 and 3/9 patients in the 10 and 3 μg groups reacted strongly with human SCLC cells by fluorescent-activated cell sorting (FACS). Sera from all patients in the 10 μg dose group also had bactericidal activity against group B meningococci with rabbit complement. Self-limited grade 3 ataxia of unclear etiology was seen in 1 of 18 patients. Vaccination with NP-polySA-KLH resulted in consistent high-titer antibody responses, with the 10 μg dose significantly more immunogenic than the 3 μg dose. This study establishes the lowest optimally immunogenic dose of NP-polysialic acid in this NP-polysialic acid-KLH conjugate vaccine to be at least 10 μg, and it establishes the vaccine's safety. We plan to incorporate NP-polySA into a polyvalent vaccine against SCLC with four glycolipid antigens also widely expressed in SCLC-GD2, GD3, fucosylated GM1, and globo H.
    Cancer Immunology and Immunotherapy 08/2011; 61(1):9-18. DOI:10.1007/s00262-011-1083-6 · 3.64 Impact Factor
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    ABSTRACT: Evidence indicates that Bax functions as a "lipidic" pore to regulate mitochondrial outer membrane permeabilization (MOMP), the apoptosis commitment step, through unknown membrane elements. Here we show mitochondrial ceramide elevation facilitates MOMP-mediated cytochrome c release in HeLa cells by generating a previously-unrecognized mitochondrial ceramide-rich macrodomain (MCRM), which we visualize and isolate, into which Bax integrates. MCRMs, virtually non-existent in resting cells, form upon irradiation coupled to ceramide synthase-mediated ceramide elevation, optimizing Bax insertion/oligomerization and MOMP. MCRMs are detected by confocal microscopy in intact HeLa cells and isolated biophysically as a light membrane fraction from HeLa cell lysates. Inhibiting ceramide generation using a well-defined natural ceramide synthase inhibitor, Fumonisin B1, prevented radiation-induced Bax insertion, oligomerization and MOMP. MCRM deconstruction using purified mouse hepatic mitochondria revealed ceramide alone is non-apoptogenic. Rather Bax integrates into MCRMs, oligomerizing therein, conferring 1-2 log enhanced cytochrome c release. Consistent with this mechanism, MCRM Bax isolates as high molecular weight "pore-forming" oligomers, while non-MCRM membrane contains exclusively MOMP-incompatible monomeric Bax. Our recent studies in the C. elegans germline indicate that mitochondrial ceramide generation is obligate for radiation-induced apoptosis, although a mechanism for ceramide action was not delineated. Here we demonstrate that ceramide, generated in the mitochondrial outer membrane of mammalian cells upon irradiation, forms a platform into which Bax inserts, oligomerizes and functionalizes as a pore. We posit conceptualization of ceramide as a membrane-based stress calibrator, driving membrane macrodomain organization, which in mitochondria regulates intensity of Bax-induced MOMP, and is pharmacologically tractable in vitro and in vivo.
    PLoS ONE 06/2011; 6(6):e19783. DOI:10.1371/journal.pone.0019783 · 3.53 Impact Factor
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    ABSTRACT: Four randomized phase III trials conducted recently in melanoma patients in the adjuvant setting have been based in part on the correlation between antibody responses in immunized patients and improved survival. Each of these randomized trials demonstrated no clinical benefit, although again there was a significant correlation between antibody response after vaccination and disease free and overall survival. To better understand this paradox, we established a surgical adjuvant model targeting GD2 ganglioside on EL4 lymphoma cells injected into the foot pad followed by amputation at variable intervals. Our findings are (1) comparable strong therapeutic benefit resulted from treatment of mice after amputation with a GD2-KLH conjugate vaccine or with anti-GD2 monoclonal antibody 3F8. (2) The strongest correlation was between antibody induction in response to vaccination and prolonged survival. (3) Antibody titers in response to vaccination in tumor challenged mice as compared to unchallenged mice were far lower despite the absence of detectable recurrences at the time. (4) The half life of administered 3F8 monoclonal antibody (but not control antibody) in challenged mice administered was significantly shorter than the half life of 3F8 antibody in unchallenged controls. The correlation between vaccine-induced antibody titers and prolonged survival may reflect, at least in part, increased tumor burden in antibody-negative mice. Absorption of vaccine-induced antibodies by increased, although not detected tumor burden may also explain the correlation between vaccine-induced antibody titers and survival in the adjuvant clinical trials described above.
    Cancer Immunology and Immunotherapy 05/2011; 60(5):621-7. DOI:10.1007/s00262-011-0975-9 · 3.64 Impact Factor
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    ABSTRACT: One of the most widely used and potent immunological adjuvants is a mixture of soluble triterpene glycosides purified from the soap bark tree (Quillaja saponaria). Despite challenges in production, quality control, stability and toxicity, the QS-21 fraction from this extract has exhibited exceptional adjuvant properties for a range of antigens. It possesses an ability to augment clinically significant antibody and T-cell responses to vaccine antigens against a variety of infectious diseases, degenerative disorders and cancers. The recent synthesis of active molecules of QS-21 has provided a robust method to produce this leading vaccine adjuvant in high purity as well as to produce novel synthetic QS-21 congeners designed to induce increased immune responsiveness and decreased toxicity.
    Expert Review of Vaccines 04/2011; 10(4):463-70. DOI:10.1586/erv.11.18 · 4.22 Impact Factor
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    ABSTRACT: The carbohydrate antigen sialyl-Lewis(a) (sLe(a)), also known as CA19.9, is widely expressed on epithelial tumors of the gastrointestinal tract and breast and on small-cell lung cancers. Since overexpression of sLe(a) appears to be a key event in invasion and metastasis of many tumors and results in susceptibility to antibody-mediated lysis, sLe(a) is an attractive molecular target for tumor therapy. We generated and characterized fully human monoclonal antibodies (mAb) from blood lymphocytes from individuals immunized with a sLe(a)-KLH vaccine. Several mAbs were selected based on ELISA and FACS including two mAbs with high affinity for sLe(a) (5B1 and 7E3, binding affinities 0.14 and 0.04 nmol/L, respectively) and further characterized. Both antibodies were specific for Neu5Acα2-3Galβ1-3(Fucα1-4)GlcNAcβ as determined by glycan array analysis. Complement-dependent cytotoxicity against DMS-79 cells was higher (EC(50) 0.1 μg/mL vs. 1.7 μg/mL) for r7E3 (IgM) than for r5B1 (IgG1). In addition, r5B1 antibodies showed high level of antibody-dependent cell-mediated cytotoxicity activity on DMS-79 cells with human NK cells or peripheral blood mononuclear cells. To evaluate in vivo efficacy, the antibodies were tested in a xenograft model with Colo205 tumor cells engrafted into SCID (severe combined immunodeficient mice) mice. Treatment during the first 21 days with four doses of r5B1 (100 μg per dose) doubled the median survival time to 207 days, and three of five animals survived with six doses. On the basis of the potential of sLe(a) as a target for immune attack and their affinity, specificity, and effector functions, 5B1and 7E3 may have clinical utility.
    Clinical Cancer Research 02/2011; 17(5):1024-32. DOI:10.1158/1078-0432.CCR-10-2640 · 8.19 Impact Factor
  • Cancer Research 01/2011; 70(8 Supplement):2417-2417. DOI:10.1158/1538-7445.AM10-2417 · 9.28 Impact Factor
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    ABSTRACT: The 95 % ethanol extract of Astragalus has been demonstrated to have potent activity as an immunological adjuvant when administered with vaccines of various types. We endeavor here to identify the components of this extract that are responsible for this adjuvant activity. Mice were immunized with KLH conjugated to cancer carbohydrate antigens globo H and GD3 and cancer peptide antigen MUC1 combined with different Astragalus fractions or with commercially available Astragalus saponins and flavonoids. The antibody responses against cancer antigens and KLH were quantitated in ELISA assays, and toxicity was calculated by weight loss. Astragalosides II and IV were the most active components, but the toxicity of these two differed dramatically. Astragaloside II was the most toxic Astragalus component with 5-10 % weight loss at a dose of 500 µg while astragaloside IV showed no weight loss at all at this dose, suggesting that astragaloside IV might be utilized as an immunological adjuvant in future studies. Several flavonoids also had significant adjuvant activity. However, when the activities of these known immunologically active components of Astragalus (and of endotoxin) are calculated based on the extent of their presence in the 95 % ethanol extract, they provide only a small proportion of the immunological activity. This raises the possibility that additional uniquely active components of Astragalus may contribute to adjuvant activity, or that the adjuvant activity of Astragalus is greater than the activity of the sum of its parts.
    Planta Medica 12/2010; 77(8):817-24. DOI:10.1055/s-0030-1250574 · 2.35 Impact Factor
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 06/2010; 29(24). DOI:10.1002/chin.199824174
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    ABSTRACT: The saponin fraction QS-21 from Quillaja saponaria has been demonstrated to be a potent immunological adjuvant when mixed with keyhole limpet hemocyanin conjugate vaccines, as well as with other classes of subunit antigen vaccines. QS-21 adjuvant is composed of two isomers that include the apiose and xylose forms in a ratio of 65:35, respectively. The chemical syntheses of these two isomers in pure form have recently been disclosed. Herein we describe detailed in vivo immunological evaluations of these synthetic QS-21 isomeric constituents, employing the GD3-KLH melanoma antigen. With this vaccine construct, high antibody titers against GD3 ganglioside and KLH were elicited when GD3-KLH was co-administered with adjuvant, either as the individual separate synthetic QS-21 isomers (SQS-21-Api or SQS-21-Xyl), or as its reconstituted 65:35 isomeric mixture (SQS-21). These antibody titer levels were comparable to that elicited by vaccinations employing naturally derived QS-21 (PQS-21). Moreover, toxicities of the synthetic saponin adjuvants were also found to be comparable to that of naturally derived PQS-21. These findings demonstrate unequivocally that the adjuvant activity of QS-21 resides in these two principal isomeric forms, and not in trace contaminants within the natural extracts. This lays the foundation for future exploration of structure-function correlations to enable the discovery of novel saponins with increased potency, enhanced stability, and attenuated toxicity.
    Vaccine 06/2010; 28(26):4260-7. DOI:10.1016/j.vaccine.2010.04.034 · 3.49 Impact Factor
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    ABSTRACT: The success of antitumor and antiviral vaccines often requires the use of an adjuvant, a substance that significantly enhances the immune response to a coadministered antigen. Only a handful of adjuvants have both sufficient potency and acceptable toxicity for clinical investigation. One promising adjuvant is QS-21, a saponin natural product that is the immunopotentiator of choice in many cancer and infectious disease vaccine clinical trials. However, the therapeutic promise of QS-21 adjuvant is curtailed by several factors, including its scarcity, difficulty in purification to homogeneity, dose-limiting toxicity, and chemical instability. Here, we report the design, synthesis, and evaluation of chemically stable synthetic saponins. These novel, amide-modified, non-natural substances exhibit immunopotentiating effects in vivo that rival or exceed that of QS-21 in evaluations with the GD3-KLH melanoma conjugate vaccine. The highly convergent synthetic preparation of these novel saponins establishes new avenues for discovering improved molecular adjuvants for specifically tailored vaccine therapies.
    Journal of the American Chemical Society 02/2010; 132(6):1939-45. DOI:10.1021/ja9082842 · 11.44 Impact Factor
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    ABSTRACT: Autoantibodies to cancer antigens hold promise as biomarkers for early detection of cancer. Proteins that are aberrantly processed in cancer cells are likely to present autoantibody targets. The extracellular mucin MUC1 is overexpressed and aberrantly glycosylated in many cancers; thus, we evaluated whether autoantibodies generated to aberrant O-glycoforms of MUC1 might serve as sensitive diagnostic biomarkers for cancer. Using an antibody-based glycoprofiling ELISA assay, we documented that aberrant truncated glycoforms were not detected in sera of cancer patients. An O-glycopeptide microarray was developed that detected IgG antibodies to aberrant O-glycopeptide epitopes in patients vaccinated with a keyhole limpet hemocyanin-conjugated truncated MUC1 peptide. We detected cancer-associated IgG autoantibodies in sera from breast, ovarian, and prostate cancer patients against different aberrent O-glycopeptide epitopes derived from MUC1. These autoantibodies represent a previously unaddressed source of sensitive biomarkers for early detection of cancer. The methods we have developed for chemoenzymatic synthesis of O-glycopeptides on microarrays may allow for broader mining of the entire cancer O-glycopeptidome.
    Cancer Research 02/2010; 70(4):1306-13. DOI:10.1158/0008-5472.CAN-09-2893 · 9.28 Impact Factor
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    ABSTRACT: A fully synthetic anticancer vaccine 2 has been prepared via bioconjugation of unimolecular pentavalent construct 1-containing five prostate and breast cancer associated carbohydrate antigens, Globo-H, GM2, STn, TF and Tn-to maleimide-modified carrier protein KLH. An improved conjugation protocol has been developed, which allowed us to obtain a higher epitope ratio of the unimolecular pentavalent glycopeptide antigen to the carrier protein (505/1 versus 228/1 for the previous version). KLH conjugate 2 has been subsequently submitted to preclinical immunogenic evaluation in mice in the presence of QS-21 as an adjuvant. Through standard ELISA assay, this vaccine candidate showed high promise in inducing IgG and IgM antibodies against each of the five individual carbohydrate antigens. In addition, FACS analysis indicated that these antibodies were able to react with MCF-7 breast cancer cell lines expressing these five carbohydrate antigens.
    Journal of the American Chemical Society 07/2009; 131(26):9298-303. DOI:10.1021/ja901415s · 11.44 Impact Factor
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    ABSTRACT: Carbohydrate and peptide-based antitumor vaccine constructs featuring clusters of both tumor associated carbohydrate antigens and mucin-like peptide epitopes have been designed, synthesized, and studied. The mucin-based epitopes are included to act, potentially, as T-cell epitopes in order to provoke a strong immune response. Hopefully the vaccine will simulate cell surface architecture, thereby provoking levels of immunity against cancer cell types displaying such characteristics. With this central idea in mind, we designed a new vaccine type against ovarian cancer. Following advances in glycohistology, our design is based on clusters of Gb(3) antigen and also incorporates a MUC5AC peptide epitope. The vaccine is among the most complex targeted constructs to be assembled by chemical synthesis to date. The strategy for the synthesis employed a Gb(3)-MUC5AC thioester cassette as a key building block. Syntheses of both nonconjugate and KLH-conjugated vaccines constructs have been accomplished.
    Journal of the American Chemical Society 04/2009; 131(11):4151-8. DOI:10.1021/ja810147j · 11.44 Impact Factor

Publication Stats

2k Citations
377.93 Total Impact Points


  • 1994–2014
    • Memorial Sloan-Kettering Cancer Center
      • • Department of Medicine
      • • Melanoma and Sarcoma Service
      • • Department of Pediatrics
      New York, New York, United States
  • 2010
    • Columbia University
      • Department of Chemistry
      New York City, New York, United States
  • 2004
    • Cornell University
      Итак, New York, United States
  • 1998
    • Memorial Hospital, TN
      Chattanooga, Tennessee, United States