Immunotherapy In Breast Cancer Patients Research Articles

Oxidative stress-related genes score predicts prognosis and immune cell infiltration landscape characterization in breast cancer

BackgroundThe tumor microenvironment (TME) typically experiences oxidative stress (OS), marked by a high level of reactive oxygen species (ROS) that can impact tumor advancement and prognosis by modulating the behavior of tumor cells and various immune cells. Oxidative stress-related genes (OSRG) encompass a range of genes involved in ROS pathways, and their specific roles in breast cancer (BC) necessitate further investigation. MethodsUnivariate Cox analysis was performed on genes linked to the OS pathway in the Gene Set Enrichment Analysis (GSEA) database, leading to the identification of 29 significant OSRG in BC. OSRG was divided into three distinct clusters according to the expression and the OSRG score based on the differentially expressed genes (DEGs) was further calculated by principal component analysis (PCA). The correlation between OSRG score and BC clinical features, mutation characteristics, immune checkpoints and immune cell infiltration was analyzed. Establish a multiariable Cox regression model to predict OSRG score effects on clinical characteristics. ResultsSignificant differences were observed in survival analysis, enriched pathways, and immune infiltration among the three OSRG clusters based on 29 genes. Gene clusters were identified through the final selected 395 DEGs, revealing three distinct OSRG expression patterns. An OSRG score model was constructed using DEGs, demonstrating a significant association between high OSRG score and poor prognosis. Significantly, immune checkpoint-related genes exhibited a notable upregulation in the high OSRG score cohort. Additionally, a positive correlation was observed between the OSRG score and tumor mutation burden (TMB) in BC. The OSRG score holds potential implications for clinical immunotherapy in BC patients, and a nomogram was constructed with robust predictive capability for evaluating patient prognosis. ConclusionsThis study elucidated the features of OSRG within BC TME and their possible prognostic significance, offering valuable insights for the development of more targeted immunotherapy approaches for individuals with BC.

MGP+ and IDO1+ tumor-associated macrophages facilitate immunoresistance in breast cancer revealed by single-cell RNA sequencing

Immunotherapy is widely applied for the treatment of breast cancer, but to which some patients respond poorly or develop resistance. Therefore, the mechanism needs to be further studied. Transcriptomic data of 31 breast cancer patients treated with anti-programmed death receptor 1 (PD-1) was downloaded from the VIB-KULeuven Center for Cancer Biology to analyze the changes in myeloid cells in tumor tissues before and after immunotherapy. And 24 cell populations that may be immune-related were further identified. Representative cell populations were also screened and validated through cellular and animal experiments to evaluate the relevant molecular expression and pathways of tumor-associated macrophages (TAMs) in the tumor microenvironment.The results demonstrated that MGP+ TAMs and IDO1+ TAMs influenced the efficacy of immunotherapy in breast cancer patients. After anti-PD-1 treatment, Increased numbers of MGP+ TAMs and IDO1+ TAMs in breast cancer patients upregulated pro-tumorigenic factors associated with resistance to immunosuppressive therapy. This study provides new biomarkers for immunotherapy to predict therapeutic responses and overcome potential resistance to immunotherapy. It is an important complement to the immunosuppression caused by TAMs after immunotherapy for breast cancer.

Acyl-CoA Thioesterase 8 (ACOT8) is a Poor Prognostic Biomarker in Breast Cancer.

This study aimed to investigate the expression of Acyl-CoA thioesterase 8 (ACOT8) in breast cancer (BC) and its association with clinicopathological characteristics, patient survival, and immune infiltration. We conducted a comprehensive analysis of ACOT8 mRNA differential expression across various cancer types, followed by survival analysis. We focused on BC, where ACOT8 expression was evaluated at both the mRNA and protein levels using online databases, qRT-PCR, and immunohistochemistry. Associations between ACOT8 expression and clinicopathological parameters were assessed using different databases. Additionally, we investigated the prognostic significance of ACOT8 in BC patients by analyzing various cohorts and databases. Furthermore, we predicted a potential signaling pathway and identified miR-1-3p as a possible upstream regulator of ACOT8. Finally, the relationship between ACOT8 and immune system infiltration, as well as immune checkpoint molecules, was examined. Our findings demonstrated upregulated ACOT8 mRNA and protein levels in BC. Elevated ACOT8 expression correlated positively with various clinicopathological characteristics, indicating an unfavorable prognosis for patients. Functional enrichment analysis suggested ACOT8 involvement in lipid metabolism, mitochondrial components, and ribosomal functions. Moreover, we identified connections between ACOT8 and immune system markers, immune cell infiltration, and immune checkpoints. This study provides compelling evidence for ACOT8 upregulation in BC and its association with clinicopathological features and patient outcomes. Additionally, our findings suggest that targeting ACOT8 and immune checkpoints might enhance the effectiveness of immunotherapy in BC patients.

Construction of stemness gene score by bulk and single-cell transcriptome to characterize the prognosis of breast cancer.

Breast cancer (BC) is a heterogeneous disease characterized by significant differences in prognosis and therapy response. Numerous prognostic tools have been developed for breast cancer. Usually these tools are based on bulk RNA-sequencing (RNA-Seq) and ignore tumor heterogeneity. Consequently, the goal of this study was to construct a single-cell level tool for predicting the prognosis of BC patients. In this study, we constructed a stemness-risk gene score (SGS) model based on single-sample gene set enrichment analysis (ssGSEA). Patients were divided into two groups based on the median SGS. Patients with a high SGS scores had a significantly worse prognosis than those with a low SGS, and these groups exhibited differences in several tumor characteristics, such as immune infiltration, gene mutations, and copy number variants. Our results indicate that the SGS is a reliable tool for predicting prognosis and response to immunotherapy in BC patients.

A novel immune score model predicting the prognosis and immunotherapy response of breast cancer

Breast cancer (BC) is one of the most common malignancies. However, the existing pathological grading system cannot accurately and effectively predict the survival rate and immune checkpoint treatment response of BC patients. In this study, based on The Cancer Genome Atlas (TCGA) database, a total of 7 immune-related genes (IRGs) were screened out to construct a prognostic model. Subsequently, the clinical prognosis, pathological characteristics, cancer-immunity cycle, tumour immune dysfunction and exclusion (TIDE) score, and immune checkpoint inhibitor (ICI) response were compared between the high- and low-risk groups. In addition, we determined the potential regulatory effect of NPR3 on BC cell proliferation, migration, and apoptosis. The model consisting of 7 IRGs was an independent prognostic factor. Patients with lower risk scores exhibited longer survival times. Moreover, the expression of NPR3 was increased but the expression of PD-1, PD-L1, and CTLA-4 was decreased in the high-risk group compared to the low-risk group. In addition, compared with si-NC, si-NPR3 suppressed proliferation and migration but promoted apoptosis in both MDA-MB-231 and MCF-7 cells. This study presents a model for predicting survival outcomes and provides a strategy to guide effective personalized immunotherapy in BC patients.

Neutrophil extracellular traps (NETs)-related lncRNAs signature for predicting prognosis and the immune microenvironment in breast cancer.

Background: Neutrophil extracellular traps (NETs) are closely associated to tumorigenesis and development. However, the relationship between NETs-related long non-coding RNAs (lncRNAs) and the characteristics of breast tumor remains an enigma. This study aimed to explore the clinical prognostic value of NETs-related lncRNAs, their correlation with the tumor microenvironment (TME) and their predictive ability of drug sensitivity in patients with breast cancer (BC). Methods: The expression profiles of RNA-sequencing and relevant clinical data of BC patients were extracted from TCGA database. The co-expression network analysis, univariable, least absolute shrinkage and selection operator (LASSO) and multivariable Cox algorithms were employed to construct the NETs-related lncRNAs signature. A nomogram was established and validated to explore the clinical application. Furthermore, the immune microenvironment and drug sensitivity for BC with different prognostic risks were explored. Finally, the expression pattern of lncRNAs was validated using qRT-PCR in BC tissues and their adjacent non-cancerous tissues. Results: Based on NETs-related lncRNAs, a prognostic risk model consisted of 10 lncRNAs (SFTA1P, ACTA2-AS1, AC004816.2, AC000067.1, LINC01235, LINC01010, AL133467.1, AC092919.1, AL591468.1, and MIR200CHG) was established. The Kaplan-Meier analysis showed that the overall survival (OS) was significantly better in low-risk BC patients than in high-risk BC patients (P training cohort < 0.001, P validation cohort = 0.009). The nomogram also showed good predictive accuracy for OS of BC individuals in both training and validation cohorts. The function enrichment analysis revealed that high-risk group was mainly enriched in immune-related functions and pathways, and the tumor mutation burden in this group was markedly higher than that in the low-risk group (p = 0.022). Moreover, significant differences were observed in immune cells, immune functions and immune checkpoint genes among BC patients at different risks (p < 0.05). The response to chemotherapeutic agents and immunotherapy were also closely related with the expression of NETs-related lncRNAs (p < 0.001). The expression of lncRNAs from experimental validation were generally consistent with the bioinformatics analysis results. Conclusion: Our study provided a novel prognostic model for BC and yielded strong scientific rationale for individualized treatment strategies, elucidating immunotherapy in BC patients.

Comprehensive analysis of the relationship between the ferroptosis and tumor-infiltrating immune cells, mutation, and immunotherapy in breast cancer.

BackgroundFerroptosis is a kind of programmed cell death that is characterized by iron dependence. It differs from apoptosis, necrosis, autophagy, pyroptosis, and other types of cell death. Some studies have found that most of the genes involved in the regulation of ferroptosis or act as markers of ferroptosis are related to the poor prognosis of cancer patients.MethodsThis study evaluated the expression, mutation, and copy number variation (CNV) of 60 previously reported ferroptosis genes in breast cancer samples from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Unsupervised clustering of breast cancer samples with ferroptosis genes was performed, followed by enrichment analysis with Gene Set Variation Analysis (GSVA), mutation display, and correlation analysis of clinical characteristics. Based on the analysis of differences among groups, the ferroptosis-related genes were identified, and the consistent clustering of breast cancer samples was performed. The characteristic genes were screened by stochastic forest algorithm and COX analysis, and a ferroptosis score (ferr.score) model was constructed to evaluate the prognosis of breast cancer patients.ResultsCopy number amplification and deletion of ferroptosis genes are common in breast cancer. Breast cancer patients grouped by ferroptosis gene clusters showed significant differences in survival, immune cell infiltration, and enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways. The ferroptosis-related differential genes were identified by comparison among clustering groups of ferroptosis gene. Characteristic genes were screened from these ferroptosis-related differential genes to construct the ferr.score model. The scoring model could accurately distinguish and predict the survival prognosis and immunotherapy efficacy in breast cancer patients.ConclusionsFerroptosis plays an important role in the occurrence and development of tumors. According to the ferr.score model, the breast cancer samples can be divided into two groups with significantly different prognoses. These results provide novel insights and ideas for immunotherapy in breast cancer patients.

Immunotherapy in Breast Cancer Patients: A Focus on the Use of the Currently Available Biomarkers in Oncology

Immune Checkpoint Inhibitors (ICIs) have remarkably modified the way solid tumors are managed, including breast cancer. Unfortunately, only a relatively small number of breast cancer patients significantly respond to these treatments. To maximize the immunotherapy benefit in breast cancer, several efforts are currently being put forward for the identification of i) the best therapeutic strategy (i.e. ICI monotherapy or in association with chemotherapy, radiotherapy, or other drugs); ii) optimal timing for administration (e.g. early/advanced stage of disease; adjuvant/ neoadjuvant setting); iii) most effective and reliable predictive biomarkers of response (e.g. tumor-infiltrating lymphocytes, programmed death-ligand 1, microsatellite instability associated with mismatch repair deficiency, and tumor mutational burden). In this article, we review the impacts and gaps in the characterization of immune-related biomarkers raised by clinical and translational research studies with immunotherapy treatments. Particular emphasis has been put on the documented evidence of significant clinical benefits of ICI in different randomized clinical trials, along with preanalytical and analytical issues in predictive biomarkers pathological assessment.

Immunotherapy in Breast Cancer Patients: A Focus on the Use of the Currently Available Biomarkers in Oncology

Immunotherapy in Breast Cancer Patients: A Focus on the Use of the Currently Available Biomarkers in Oncology

Determining Factors in the Therapeutic Success of Checkpoint Immunotherapies against PD-L1 in Breast Cancer: A Focus on Epithelial-Mesenchymal Transition Activation.

Breast cancer is the most common neoplasm diagnosed in women around the world. Checkpoint inhibitors, targeting the programmed death receptor-1 or ligand-1 (PD-1/PD-L1) axis, have dramatically changed the outcome of cancer treatment. These therapies have been recently considered as alternatives for treatment of breast cancers, in particular those with the triple-negative phenotype (TNBC). A further understanding of the regulatory mechanisms of PD-L1 expression is required to increase the benefit of PD-L1/PD-1 checkpoint immunotherapy in breast cancer patients. In this review, we will compile the most recent studies evaluating PD-1/PD-L1 checkpoint inhibitors in breast cancer. We review factors that determine the therapeutic success of PD-1/PD-L1 immunotherapies in this pathology. In particular, we focus on pathways that interconnect the epithelial-mesenchymal transition (EMT) with regulation of PD-L1 expression. We also discuss the relationship between cellular metabolic pathways and PD-L1 expression that are involved in the promotion of resistance in TNBC.

Immunotherapy in Breast Cancer Patients: A Focus on the Use of the CurrentlyAvailable Biomarkers in Oncology

Immune checkpoint inhibitors (ICIs) have remarkably modified the way solid tumors are managed, including breast cancer. Unfortunately, only a relatively small number of breast cancer patients significantly respond to these treatments. To maximize the immunotherapy benefit in breast cancer, several efforts are currently being put forward for the identification of i) the best therapeutic strategy (i.e. ICI monotherapy or in association with chemotherapy, radiotherapy, or other drugs); ii) the optimal timing for administration (e.g. early/advanced stage of disease; adjuvant/neoadjuvant setting); iii) the most effective and reliable predictive biomarkers of response (e.g. tumor-infiltrating lymphocytes, programmed death-ligand 1, microsatellite instability associated with mismatch repair deficiency, and tumor mutational burden). In this article, we review the impacts and gaps in the characterization of immune-related biomarkers raised by clinical and translational research studies with immunotherapy treatments. Particular emphasis has been put on the documented evidence of significant clinical benefits of ICI in different randomized clinical trials, along with preanalytical and analytical issues in predictive biomarkers pathological assessment.

Abstract IA31: What limits the response of breast cancer to immunotherapy?

Abstract Checkpoint blockade has been evaluated successfully in the classically immunogenic solid tumor types such as melanoma and renal cell carcinoma, as well as in hematologic malignancies. While a large degree of T-cell infiltrate has been observed in primary breast cancers, particularly triple-negative and Her2-positive subtypes, efficacy with checkpoint blockade as monotherapy has been modest so far in studies in advanced disease. Given that higher levels of T-cell infiltrate have been associated with improved prognoses and response to cytotoxic chemotherapy, my lab has hypothesized that these T cells would have functional characteristics that would be important in immunosurveillance of breast cancer. We have characterized these T cells using methods such as multiplex immunohistochemistry, bulk gene expression, and flow cytometry, as well as single-cell transcriptomic sequencing in order to better characterize these T cells. We have also observed lower levels of immune infiltrate in samples from metastatic breast cancer lesions, suggesting that the primary disease setting may be the most amenable to checkpoint inhibitor approaches. Data currently support that line of therapy in the advanced breast cancer setting; tumor burden and T-cell infiltrate predict for higher response rates to PD-1 blockade as monotherapy. Finally, given that most patients with advanced breast cancer have a “noninflamed” tumor microenvironment, my lab has been evaluating how therapeutics can modulate the immune microenvironment. Certain agents such as MEK inhibitors as well as combination targeted therapies can potentially increase tumor immunogenicity as well as synergize well with immunotherapies. These combinatorial approaches may serve to increase the response rate of immunotherapy in breast cancer patients as well as prolong duration of response in patients treated with new therapeutic agents. Citation Format: Sherene Loi. What limits the response of breast cancer to immunotherapy? [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr IA31.

In vitro culture of tumor infiltrating lymphocytes for adoptive immunotherapy in breast cancer patients

In vitro culture of tumor infiltrating lymphocytes for adoptive immunotherapy in breast cancer patients

Elevated T cell activation score is associated with improved survival of breast cancer

Immune checkpoints cytotoxic T lymphocyte antigen 4 (CTLA4) and programmed cell death 1 receptor (PD-1) negatively regulate CD8+ T cell functions, impeding the capacity of effector T cells to kill tumors. Here, we study the prognostic significance of CTLA4, PD-1 and T cell activation status in breast cancer. Using a publicly accessed RNA-seq dataset including 1087 breast cancer patients, we performed Kaplan-Meier survival curves and multivariate Cox regression models to evaluate the associations of CTLA4, PD-1, and weighted T cell activation score with patients' overall survival. Survival analyses showed that high CTLA4 but low PD-1 expression was associated with a poor overall survival, and that high T cell activation score was associated with an improved survival. The median survival was 216.6months (95% CI 114.1-244.9) for the T activation group, 127.0months (95% CI 112.3-212.1) for the intermediate, and 120.5months (95% CI 93.8 to ∞) for the exhaustion (Log-rank p=0.084). This association was verified in multivariate Cox regression analysis. The hazard ratios were 0.81 (95% CI 0.56-1.19) for the intermediate group, and 0.48 (95% CI 0.26-0.86) for the activation group, respectively, in comparison to the exhaustion group (p value for trend=0.016). T cell activation score has significantly positive relationship with patients' overall survival, and may serve as a marker of personalized immunotherapy in breast cancer patients. Cocktail rather than single immune checkpoint blockade may yield more benefit for breast cancer patients.

Abstract B70: Canine Parvovirus-based immunotherapy in breast cancer patients, as coadjuvant treatment to surgery management: 9 years survival following

Abstract Introduction: The Cancer Reserch Laboratory (LIC) during the last twenty years generated a product of research to develop a new option therapeutic for the cancer, based in immunotherapy, that decreases them effects side in comparison with them treatments conventional. Previous studies in experimental models in vitro and in vivo with Rathus wistar murinidae showed that it stimulates cell proliferation and reviving the immune system, without evidence of pathophysiological changes or cytotoxicity in the subject of study. Therefore developed the research protocol entitled “The biological CIMT-54 cancer vaccine clinical-therapeutic Protocol”, based on the number of US patent US9.056.070B12 immunotherapy, associated with the use of canine Parvovirus, which involved nine patients diagnosed with breast cancer. The objective of the present study was to evaluate the clinical behavior of patients during nine years of follow-up. Methodology: A study of retrospective cases that included nine cases of breast cancer who were treated with mastectomy or quadrantectomy which rejected conventional consolidation (chemotherapy and radiation therapy) treatment, and we entered the Protocol for handling with immunotherapy using biological vaccine CIMT-54, the Cancer Research Laboratory in 2007, prior informed consent. The follow-up of each of the cases included the anamnesis of the patient, physical examination, ultrasound, mammography, chest x-rays and lab tests. The collection of the information is obtained from the stories clinical evaluated. Results: During the year 2007, admitted to the study “Protocol clinical-therapeutic of the vaccine biological ITTA-54 against the cancer”, nine patients with diagnosis of cancer of breast treated previously with mastectomy and in some cases quadrantectomy; all patients received treatment with the biological vaccine CIMT-54 with six doses in the following way: the first three doses of weekly and monthly dose for three months, none presented recurrence locoregional or metastasis during the evaluated period of nine years. Discussion and Conclusions: Sequentially, the study describes the evolution of the nine patients who were treated with biological vaccine CIMT-54 after surgery, none presented recurrence locoregional or metastasis, during nine years of follow-up, unlike other studies in which post mastectomy initiated processes of radiotherapy or chemotherapy where 6.3% of recurrences have shown In addition to the side effects that can generate this type of conventional treatments. We are still in the process of making molecular analyses more detailed, but is could be considered as an alternative adjuvant to conventional management, without side effects, and proven in the long run. Citation Format: Hugo Ramiro Segura-Puello, Juan Sebastian Segura-Charry, Ingrid Tatiana Gomez-Martinez, Sandra Viviana Guitarrero-Bustos, Diana Lorena Nieto-Mosquera. Canine Parvovirus-based immunotherapy in breast cancer patients, as coadjuvant treatment to surgery management: 9 years survival following. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr B70.

Canine Parvovirus-based Immunotherapy in Breast Cancer Patients, as Coadjuvant Treatment to Surgery Management: 9 Years Survival Following

Canine Parvovirus-based Immunotherapy in Breast Cancer Patients, as Coadjuvant Treatment to Surgery Management: 9 Years Survival Following

A FISH-based method for assessment of HER-2 amplification status in breast cancer circulating tumor cells following CellSearch isolation.

IntroductionAmplification of the HER-2/neu (HER-2) proto-oncogene occurs in 10%–15% of primary breast cancer, leading to an activated HER-2 receptor, augmenting growth of cancer cells. Tumor classification is determined in primary tumor tissue and metastatic biopsies. However, malignant cells tend to alter their phenotype during disease progression. Circulating tumor cell (CTC) analysis may serve as an alternative to repeated biopsies. The Food and Drug Administration-approved CellSearch system allows determination of the HER-2 protein, but not of the HER-2 gene. The aim of this study was to optimize a fluorescence in situ hybridization (FISH)-based method to quantitatively determine HER-2 amplification in breast cancer CTCs following CellSearch-based isolation and verify the method in patient samples.MethodsUsing healthy donor blood spiked with human epidermal growth factor receptor 2 (HER-2)-positive breast cancer cell lines, SKBr-3 and BT-474, and a corresponding negative control (the HER-2-negative MCF-7 cell line), an in vitro CTC model system was designed. Following isolation in the CellSearch system, CTC samples were further enriched and fixed on microscope slides. Immunocytochemical staining with cytokeratin and 4′,6-diamidino-2′-phenylindole dihydrochloride identified CTCs under a fluorescence microscope. A FISH-based procedure was optimized by applying the HER2 IQFISH pharmDx assay for assessment of HER-2 amplification status in breast cancer CTCs.ResultsA method for defining the presence of HER-2 amplification in single breast cancer CTCs after CellSearch isolation was established using cell lines as positive and negative controls. The method was validated in blood from breast cancer patients showing that one out of six patients acquired CTC HER-2 amplification during treatment against metastatic disease.ConclusionHER-2 amplification status of CTCs can be determined following CellSearch isolation and further enrichment. FISH is superior to protein assessment of HER-2 status in predicting response to HER-2-targeted immunotherapy in breast cancer patients. This assay has the potential of identifying patients with a shift in HER-2 status who may benefit from treatment adjustments.

Phenotype-dependent effects of EpCAM expression on growth and invasion of human breast cancer cell lines

BackgroundThe epithelial cell adhesion molecule (EpCAM) has been shown to be overexpressed in breast cancer and stem cells and has emerged as an attractive target for immunotherapy of breast cancer patients. This study analyzes the effects of EpCAM on breast cancer cell lines with epithelial or mesenchymal phenotype.MethodsFor this purpose, shRNA-mediated knockdown of EpCAM gene expression was performed in EpCAMhigh breast cancer cell lines with epithelial phenotype (MCF-7, T47D and SkBR3). Moreover, EpCAMlow breast carcinoma cell lines with mesenchymal phenotype (MDA-MB-231, Hs578t) and inducible overexpression of EpCAM were used to study effects on proliferation, migration and in vivo growth.ResultsIn comparison to non-specific silencing controls (n/s-crtl) knockdown of EpCAM (E#2) in EpCAMhigh cell lines resulted in reduced cell proliferation under serum-reduced culture conditions. Moreover, DNA synthesis under 3D culture conditions in collagen was significantly reduced. Xenografts of MCF-7 and T47D cells with knockdown of EpCAM formed smaller tumors that were less invasive. EpCAMlow cell lines with tetracycline-inducible overexpression of EpCAM showed no increased cell proliferation or migration under serum-reduced growth conditions. MDA-MB-231 xenografts with EpCAM overexpression showed reduced invasion into host tissue and more infiltrates of chicken granulocytes.ConclusionsThe role of EpCAM in breast cancer strongly depends on the epithelial or mesenchymal phenotype of tumor cells. Cancer cells with epithelial phenotype need EpCAM as a growth- and invasion-promoting factor, whereas tumor cells with a mesenchymal phenotype are independent of EpCAM in invasion processes and tumor progression. These findings might have clinical implications for EpCAM-based targeting strategies in patients with invasive breast cancer.

Sialyl-Tn vaccine induces antibody-mediated tumour protection in a relevant murine model

Changes in the composition of glycans added to glycoproteins and glycolipids are characteristic of the change to malignancy. Sialyl-Tn (STn) is expressed by 25–30% of breast carcinomas but its expression on normal tissue is highly restricted. Sialyl-Tn is an O-linked disaccharide that can be carried on various glycoproteins. One such glycoprotein MUC1 is expressed by the vast majority of breast carcinomas. Both STn and MUC1 have been considered as targets for immunotherapy of breast cancer patients. Here we used different immunogens to target STn in an MUC1 transgenic mouse model of tumour challenge. We show that synthetic STn coupled to keyhole limpet haemocyanin (Theratope), induced antibodies to STn that recognised the glycan carried on a number of glycoproteins and in these mice a significant delay in tumour growth was observed. The protection was dependant on STn being expressed by the tumour and was antibody mediated. Affinity chromatography of the STn-expressing tumour cell line, followed by mass spectrometry, identified osteopontin as a novel STn-carrying glycoprotein which was highly expressed by the tumours. These results suggest that if antibodies can be induced to a number of targets expressed by the tumour cells, a humoral response can be effective in controlling tumour growth.

Inhibition of tumor cell growth by antibodies induced after vaccination with peptides derived from the extracellular domain of Her-2/neu.

The anti Her-2/neu monoclonal antibody Trastuzumab has strong inhibiting effects on tumor growth in vitro and in vivo and is therefore used for immunotherapy in breast cancer patients. Due to necessity of frequent applications, however, cost intensiveness of Trastuzumab treatment and its limited duration of affectivity, an active immunization inducing a perhaps preventive and long-term immunity to Her-2/neu remains a desirable goal. We attempted to induce anti Her-2/neu antibodies by peptide vaccination and to test their efficacy in inhibiting tumor cell growth in vitro. By computer aided analyses, 7 putative B cell epitopes of Her-2/neu were defined and synthesized. These peptide epitopes were coupled to tetanus toxoid and used for immunization in BALB/c mice. Among these peptides, immunizations with 2 single peptides or a combination of 2 peptides induced anti-peptide antibody levels, primarily of the IgG1 isotype. These antibodies were also directed against the native Her-2/neu antigen, as shown in precipitation assays and ELISA with cell lysates of the Her-2/neu overexpressing breast cancer cell line SK-BR-3. Isolated IgG fractions from immune sera incubated with SK-BR-3 cells led to a moderate inhibition of the tumor cell growth in vitro, as well as to complement dependent cell lyses comparable to that achieved by incubation with Trastuzumab. Moreover, peptide immunization in rabbits generated anti-Her 2-neu IgG that, in contrast to mouse sera, were able to mediate a 31-46% lysis of SK-BR-3 cells in ADCC experiments. We conclude from our data that immunization with Her-2/neu peptides successfully induced humoral immune response with anti-tumor activity in an animal model.