Jon Ladd

Increased plasma levels of the APC-interacting protein MAPRE1, LRG1, and IGFBP2 preceding a diagnosis of colorectal cancer in women.

Longitudinal blood collections from cohort studies provide the means to search for proteins associated with disease before clinical diagnosis. We investigated plasma samples from the Womens Health Initiative (WHI) cohort to determine quantitative differences in plasma proteins between subjects subsequently diagnosed with colorectal cancer (CRC) and matched controls that remained cancer-free during the period of follow-up. Proteomic analysis of WHI samples collected before diagnosis of CRC resulted in the identification of six proteins with significantly (P < 0.05) elevated concentrations in cases compared with controls. Proteomic analysis of two CRC cell lines showed that five of the six proteins were produced by cancer cells. Microtubule-associated protein RP/EB family member 1 (MAPRE1), insulin-like growth factor–binding protein 2 (IGFBP2), leucine-rich alpha-2-glycoprotein (LRG1), and carcinoembryonic antigen (CEA) were individually assayed by enzyme linked immunosorbent assay (ELISA) in 58 pairs of newly diagnosed CRC samples and controls and yielded significant elevations (P < 0.05) among cases relative to controls. A combination of these four markers resulted in a receiver operating characteristics curve with an area under the curve value of 0.841 and 57% sensitivity at 95% specificity. This combination rule was tested in an independent set of WHI samples collected within 7 months before diagnosis from cases and matched controls resulting in 41% sensitivity at 95% specificity. A panel consisting of CEA, MAPRE1, IGFBP2, and LRG1 has predictive value in prediagnostic CRC plasmas. Cancer Prev Res; 5(4); 655–64. ©2012 AACR.

Evaluation of Known Oncoantibodies, HER2, p53, and Cyclin B1, in Prediagnostic Breast Cancer Sera

Serum autoantibodies, directed against oncogenic proteins, have been frequently detected in the sera of patients with breast cancer. It is unknown whether serum antibodies that are identified in patients with established disease could also be detected in patients with newly diagnosed disease or even predate the diagnosis of breast cancer. Using sera collected at the time of treatment, at the time of diagnosis, or before the time of diagnosis, the current study aimed to address the temporal relationship between breast cancer development and serum antibody response. Starting from serum antibodies to eight known breast cancer antigens, we first identified four serum antibodies, HER2/neu, p53, carcinoembryonic antigen (CEA), and cyclin B1, which are significantly increased in the sera collected from patients with breast cancer at the time of treatment. These antibodies were also elevated in breast cancer sera collected at the time of diagnosis. Finally, comparison of antibody responses in prediagnostic samples from women before the development of breast cancer and in controls showed that antibodies to the HER2/neu and p53 can be detected in sera that were collected on average more than 150 days before a breast cancer diagnosis. These results showed that serum autoantibodies commonly reported in sera from patients with established disease can also be detected in prediagnostic sera and may be useful for the early detection of breast cancer. Cancer Prev Res; 5(8); 1036–43. ©2012 AACR.

Autoantibody Signatures Involving Glycolysis and Splicesome Proteins Precede a Diagnosis of Breast Cancer among Postmenopausal Women

We assessed the autoantibody repertoire of a mouse model engineered to develop breast cancer and the repertoire of autoantibodies in human plasmas collected at a preclinical time point and at the time of clinical diagnosis of breast cancer. In seeking to identify common pathways, networks, and protein families associated with the humoral response, we elucidated the dynamic nature of tumor antigens and autoantibody interactions. Lysate proteins from an immortalized cell line from a MMTV-neu mouse model and from MCF7 human breast cancers were spotted onto nitrocellulose microarrays and hybridized with mouse and human plasma samples, respectively. Immunoglobulin-based plasma immunoreactivity against glycolysis and spliceosome proteins was a predominant feature observed both in tumor-bearing mice and in prediagnostic human samples. Interestingly, autoantibody reactivity was more pronounced further away than closer to diagnosis. We provide evidence for dynamic changes in autoantibody reactivity with tumor development and progression that may depend, in part, on the extent of antigen-antibody interactions.

Concordant Release of Glycolysis Proteins into the Plasma Preceding a Diagnosis of ER+ Breast Cancer

Although the identification of peripheral blood biomarkers would enhance early detection strategies for breast cancer, the discovery of protein markers has been challenging. In this study, we sought to identify coordinated changes in plasma proteins associated with breast cancer based on large-scale quantitative mass spectrometry. We analyzed plasma samples collected up to 74 weeks before diagnosis from 420 estrogen receptor (ER)(+) cases and matched controls enrolled in the Womens Health Initiative cohort. A gene set enrichment analysis was applied to 467 quantified proteins, linking their corresponding genes to particular biologic pathways. On the basis of differences in the concentration of individual proteins, glycolysis pathway proteins exhibited a statistically significant difference between cases and controls. In particular, the enrichment was observed among cases in which blood was drawn closer to diagnosis (effect size for the 0-38 weeks prediagnostic group, 1.91; P, 8.3E-05). Analysis of plasmas collected at the time of diagnosis from an independent set of cases and controls confirmed upregulated levels of glycolysis proteins among cases relative to controls. Together, our findings indicate that the concomitant release of glycolysis proteins into the plasma is a pathophysiologic event that precedes a diagnosis of ER(+) breast cancer.

An Autoimmune Response Signature Associated with the Development of Triple-Negative Breast Cancer Reflects Disease Pathogenesis

The repertoire of antigens associated with the development of an autoimmune response in breast cancer has relevance to detection and treatment strategies. We have investigated the occurrence of autoantibodies associated with the development of triple-negative breast cancer (TNBC) in the before diagnosis setting and in samples collected at the time of diagnosis of TNBC. Lysate arrays containing protein fractions from the TNBC MDA-MB-231 cell line were hybridized with TNBC plasmas from the Womens Health Initiative cohort, collected before clinical diagnosis and with plasmas from matched controls. An immune response directed against spliceosome and glycolysis proteins was observed with case plasmas as previously reported in estrogen receptor(+) breast cancer. Importantly, autoantibodies directed against networks involving BRCA1, TP53, and cytokeratin proteins associated with a mesenchymal/basal phenotype were distinct to TNBC before diagnosis samples. Concordant autoantibody findings were observed with mouse plasma samples collected before occurrence of palpable tumors from a C3(1)-T triple negative mouse model. Plasma samples collected at the time of diagnosis of stage II TNBC and from matched healthy controls were subjected to proteomic analysis by mass spectrometry to identify Ig-bound proteins yielding a predominance of cytokeratins, including several associated with a mesenchymal/basal phenotype among cases compared with controls. Our data provide evidence indicative of a dynamic repertoire of antigens associated with a humoral immune response reflecting disease pathogenesis in TNBC.

Protein and glycomic plasma markers for early detection of adenoma and colon cancer

Objective To discover and confirm blood-based colon cancer early-detection markers. Design We created a high-density antibody microarray to detect differences in protein levels in plasma from individuals diagnosed with colon cancer <3 years after blood was drawn (ie, prediagnostic) and cancer-free, matched controls. Potential markers were tested on plasma samples from people diagnosed with adenoma or cancer, compared with controls. Components of an optimal 5-marker panel were tested via immunoblotting using a third sample set, Luminex assay in a large fourth sample set and immunohistochemistry (IHC) on tissue microarrays. Results In the prediagnostic samples, we found 78 significantly (t-test) increased proteins, 32 of which were confirmed in the diagnostic samples. From these 32, optimal 4-marker panels of BAG family molecular chaperone regulator 4 (BAG4), interleukin-6 receptor subunit beta (IL6ST), von Willebrand factor (VWF) and CD44 or epidermal growth factor receptor (EGFR) were established. Each panel member and the panels also showed increases in the diagnostic adenoma and cancer samples in independent third and fourth sample sets via immunoblot and Luminex, respectively. IHC results showed increased levels of BAG4, IL6ST and CD44 in adenoma and cancer tissues. Inclusion of EGFR and CD44 sialyl Lewis-A and Lewis-X content increased the panel performance. The protein/glycoprotein panel was statistically significantly higher in colon cancer samples, characterised by a range of area under the curves from 0.90 (95% CI 0.82 to 0.98) to 0.86 (95% CI 0.83 to 0.88), for the larger second and fourth sets, respectively. Conclusions A panel including BAG4, IL6ST, VWF, EGFR and CD44 protein/glycomics performed well for detection of early stages of colon cancer and should be further examined in larger studies.

Proteomic profiling of the autoimmune response to breast cancer antigens uncovers a suppressive effect of hormone therapy

Proteomics technologies are well suited for harnessing the immune response to tumor antigens for diagnostic applications as in the case of breast cancer. We previously reported a substantial impact of hormone therapy (HT) on the proteome. Here, we investigated the effect of HT on the immune response toward breast tumor antigens.

Abstract 2491: Dynamics changes in antigen-autoantibody profiles involving glycolysis and spliceosome proteins precede a diagnosis of ER+ and triple negative breast cancer among post-menopausal women.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC We assessed the circulating autoantibody repertoire in breast cancer using genetically engineered mouse models and human plasmas collected at a pre-clinical time point and at the time of clinical diagnosis of breast cancer. We aimed to identify common pathways, networks and protein families associated with the humoral response to tumors and to elucidate the dynamic nature of tumor antigens and autoantibody interactions in ER+ and triple negative breast cancer. Lysate proteins from immortalized mouse cell lines from MMTV-neu and C3(1)-T mouse models and from the MCF7 and MDA-MB-231 human breast cancer cell lines were spotted onto nitrocellulose microarrays and hybridized with mouse and human plasma samples, respectively. Ig-based plasma immunoreactivity against glycolysis and spliceosome proteins was a predominant feature observed both in MMTV-neu tumor bearing mice and in pre-diagnostic ER+ human samples. A cytoskeletal signature was uniquely observed in C3(1)-T mice and in human patients with triple negative breast cancer. We provide evidence for dynamic changes in autoantibody reactivity and in antigen-antibody interactions with tumor development and progression. Citation Format: Jon Ladd, Melissa Johnson, Timothy Chao, Alice Chin, Sharon Pitteri, Jianning Mao, Lynn M. Amon, Martin McIntosh, Paul Lampe, Christopher Li, Ross Prentice, Nora Disis, Samir Hanash. Dynamics changes in antigen-autoantibody profiles involving glycolysis and spliceosome proteins precede a diagnosis of ER+ and triple negative breast cancer among post-menopausal women. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2491. doi:10.1158/1538-7445.AM2013-2491

Abstract P5-01-09: Early tumor antigens discovered in TgMMTV-neu mice may provide targets for early breast cancer diagnosis and prevention

Breast cancer is immunogenic and breast tumor proteins stimulate both an antibody and a T cell immune response. Identification of cancer related proteins that become immunogenic prior to the clinical development of cancer may allow the use of humoral immunity to identify those “exposed” to the cancer phenotype. Alternatively, these proteins that become aberrant enough to trigger such early immune recognition may be ideal targets for a vaccine aimed at preventing the development of breast cancer. We used the TgMMTV-neu mouse model to discover immunogenic proteins i.e. proteins expressed in pre-invasive breast cancer. The mammary tumors in these mice are genotypically similar to human luminal breast cancer and can be evaluated longitudinally, allowing for collection of pre-diagnostic sera prior to tumor development to use for antigen discovery. We identified 6 antigens that were present in mice prior to the development of mammary cancer (Pdhx, Otud6b, Stk39, Zpf238, Lgals8, and Vps35). These proteins were associated with inflammation, autoimmunity, and cellular homeostasis. In mouse validation cohorts, detecting IgM and IgG antibody responses against a panel of three “pre-diagnostic” tumor antigens discriminated pre-diagnostic sera from non-transgenic control sera with an AUC of 0.924. We next evaluated samples obtained from the Womens Health Initiative Study and demonstrated women with autoantibodies to the human homologues of these proteins. IgM and IgG autoantibodies to the “pre-diagnostic” antigen panel could discriminate the samples of women who eventually developed breast cancer from matched controls. The discriminatory potential of the pre-diagnostic autoantibodies was enhanced if samples were collected more than 5 months prior to diagnosis (AUC 0.68; CI 0.565-0.787). We questioned whether these antigens, which could predict women who would eventually develop breast cancer, could mediate anti-tumor immunity. When TgMMTV-neu mice (n = 5/group) were vaccinated with the individual antigens, vaccination with Pdhx inhibited tumor growth by 62.1%, Otud6B inhibited tumor growth by 23.5%, and Stk39 inhibited tumor growth by 50.3% as compared to empty vector vaccinated control at 27 weeks (p<0.001 for each of the individual antigens as compared to empty vector). Spontaneous tumorigenesis was inhibited in TgMMTV-neu mice (n = 20 mice/group) vaccinated with a panel of three of the “pre-diagnostic” antigens (Pdhx, Otud6b, and Stk39) inhibited tumor growth by 27.3% by 37 weeks as compared to vector vaccinated mice (p<0.05). These data suggest that the same pre-invasive breast tumor proteins are found in mice and women and vaccines against these pre-invasive breast cancer proteins inhibit tumorigenesis in mice, future studies will address if these antigens elicit T-cell responses in patients with high risk breast lesions. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-01-09.

Abstract 2683: Identification of tumor antigens in neu transgenic mice as diagnostic targets for the early detection of human breast cancer

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Tumor antigens, expressed early in disease, which can induce specific antibody response could serve as biomarkers for early detection of human breast cancer. However, the ability to obtain sera from women prior to the development of breast cancer is limited, which makes it difficult to identify early antigens directly from breast cancer patients. Transgenic mouse models have been proved to demonstrate similar antigen repertoire to breast cancer patients. Therefore, we propose to identify early tumor antigens in neu transgenic mice and use them as diagnostic targets for early detection of human breast cancer. We have collected serial sera from neu transgenic mice, sera collected before the animals develop palpable tumor “pre-diagnostic sera”. With serological analysis of recombinant cDNA expression libraries (SEREX) approach, we were able to identify nine tumor antigens from pre-diagnostic sera, Rpl5, TNFaip3/A20, Pdhx, Otud6b, Stk39, Zfp238, Dnajc10, Lgals8 and Vps35. These antigens demonstrated detectable IgG antibody response prior to tumor development in neu transgenic mice. IgM is the first antibody to be produced during a humoral immune response, so we questioned whether including antigen specific IgM with IgG responses could achieve a better diagnostic performance. Firstly, we analyzed receiver-operating-characteristic (ROC) curves of these antigens by IgG and IgM ELISA analysis in neu transgenic mice and 26 FVB control mice. By combining IgG and IgM ELISA, we were able to achieve a higher AUC: Otud6b and Stk39 show an AUC of 0.882, and adding Lgals8 IgG ELISA to this panel can achieve an AUC of 0.924 in discriminating cases from control mice. We documented that these autoantibodies are also detectable in the serum of women with breast cancer and then screened a panel of sera derived from the Womens Health Initiative cohort (samples obtained 6-18 months prior to the development of breast cancer) and case matched controls. We evaluated serum for the presence of IgG and IgM specific autoantibodies to Pdhx, Otud6b, and Stk39. With both IgG and IgM ELISA analysis, a panel combining the three antigens demonstrates an AUC of 0.633 in patients diagnosed within 5 month and an AUC of 0.688 in patients diagnosed within 5-18 month of the blood draw. In summary, we conclude that tumor antigens identified in neu transgenic mouse model can be used for early detection and diagnosis of breast cancer in women. The combination of antigen specific IgG and IgM antibodies may enhance the sensitivity of the assay for early detection. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2683. doi:10.1158/1538-7445.AM2011-2683