Response of established human breast tumors to vaccination with mammaglobin-A cDNA

Understanding the relationship between silicone implants, tumor antigens, and breast cancer risk: An immunological study in rats

This study aimed to investigate the effects of silicone implants on the incidence of breast cancer in rats, as well as their impact on immune surveillance mechanisms. Female SD rats were divided into three groups: a Placebo Surgery Group (PSG), a Thoracic Implant Group (TIG), and a Back Implant Group (BIG). Following the corresponding surgical procedures, we measured Secretoglobin Family 2A, Member 2(SCGB2A2) and Mucin-1 (MUC1) antigen levels using ELISA, and statistical analyses were conducted to evaluate immune responses. The N-Methyl-N-Nitrosourea(MNU)-induced breast cancer model and pathological analyses indicated that the incidence of breast cancer in the thoracic implant group was lower, suggesting that silicone implants may reduce the risk of breast cancer. Additionally, laser speckle blood flow imaging and immunohistochemical analysis revealed blood perfusion in the implant capsule area and an active response of immune cells, indicating that immune surveillance may exert local effects. These findings provide the first evidence of a relationship between tumor antigens, silicone implants, and breast cancer incidence, offering a new immunological perspective on the safety of silicone implants.

ROS-Responsive Nanoprobes for Bimodal Imaging-Guided Cancer Targeted Combinatorial Therapy

Purpose

Chemotherapy mediated by Reactive oxygen species (ROS)-responsive drug delivery systems can potentially mitigate the toxic side effects of chemotherapeutic drugs and significantly enhance their therapeutic efficacy. However, achieving precise targeted drug delivery and real-time control of ROS-responsive drug release at tumor sites remains a formidable challenge. Therefore, this study aimed to describe a ROS-responsive drug delivery system with specific tumor targeting capabilities for mitigating chemotherapy-induced toxicity while enhancing therapeutic efficacy under guidance of Fluorescence (FL) and Magnetic resonance (MR) bimodal imaging.

Methods

Indocyanine green (ICG), Doxorubicin (DOX) prodrug pB-DOX and Superparamagnetic iron oxide (SPIO, Fe3O4) were encapsulated in poly(lactic-co-glycolic acid) (PLGA) by double emulsification method to prepare ICG/ pB-DOX/ Fe3O4/ PLGA nanoparticles (IBFP NPs). The surface of IBFP NPs was functionalized with mammaglobin antibodies (mAbs) by carbodiimide method to construct the breast cancer-targeting mAbs/ IBFP NPs (MIBFP NPs). Thereafter, FL and MR bimodal imaging ability of MIBFP NPs was evaluated in vitro and in vivo. Finally, the combined photodynamic therapy (PDT) and chemotherapy efficacy evaluation based on MIBFP NPs was studied.

Results

The multifunctional MIBFP NPs exhibited significant targeting efficacy for breast cancer. FL and MR bimodal imaging clearly displayed the distribution of the targeting MIBFP NPs in vivo. Upon near-infrared laser irradiation, the MIBFP NPs loaded with ICG effectively generated ROS for PDT, enabling precise tumor ablation. Simultaneously, it triggered activation of the pB-DOX by cleaving its sensitive moiety, thereby restoring DOX activity and achieving ROS-responsive targeted chemotherapy. Furthermore, the MIBFP NPs combined PDT and chemotherapy to enhance the efficiency of tumor ablation under guidance of bimodal imaging.

Conclusion

MIBFP NPs constitute a novel dual-modality imaging-guided drug delivery system for targeted breast cancer therapy and offer precise and controlled combined treatment options.

Systemic and Local Strategies for Primary Prevention of Breast Cancer

One in eight women will develop breast cancer in the US. For women with moderate (15-20%) to average (12.5%) risk of breast cancer, there are few options available for risk reduction. For high-risk (>20%) women, such as BRCA mutation carriers, primary prevention strategies are limited to evidence-based surgical removal of breasts and/or ovaries and anti-estrogen treatment. Despite their effectiveness in risk reduction, not many high-risk individuals opt for surgical or hormonal interventions due to severe side effects and potentially life-changing outcomes as key deterrents. Thus, better communication about the benefits of existing strategies and the development of new strategies with minimal side effects are needed to offer women adequate risk-reducing interventions. We extensively review and discuss innovative investigational strategies for primary prevention. Most of these investigational strategies are at the pre-clinical stage, but some are already being evaluated in clinical trials and others are expected to lead to first-in-human clinical trials within 5 years. Likely, these strategies would be initially tested in high-risk individuals but may be applicable to lower-risk women, if shown to decrease risk at a similar rate to existing strategies, but with minimal side effects.

Immunotherapy: Constructive Approach for Breast Cancer Treatment

A novel and rapid therapeutic approach is the treatment of human breast cancer by enhancing the host's immune system. In initial findings, program death one (PD-1) and program cell death ligand one (PD-L1) showed positive results towards solid tumors, but tumor relapse and drug resistance are the major concerns. Breast cancer therapy has been transformed by the advent of immune checkpoint blockades (ICBs). Triple-negative breast cancers (TNBCs) have exhibited enduring responses to clinical usage of immune checkpoint inhibitors (ICBs) like atezolizumab and pembrolizumab. Nonetheless, a notable proportion of individuals with TNBC do not experience advantages from these treatments, and there is limited comprehension of the resistance mechanisms. Another approach to overcome resistance is cancer stem cells (CSCs), as these cells are crucial for the initiation and growth of tumors in the body. Various cancer vaccines are created using stem cells (dendritic, whole cell, bacterial) and focus primarily on targeting tumor-related antigens. The ultimate objective of cancer vaccines is to immunize the patients by active artificial immunity against cancer, though. In this review, we primarily focused on existing immunotherapeutic options, immune checkpoint blockers, the latest progress in understanding the molecular mechanisms underlying resistance to immune checkpoint inhibitors (ICBs), advanced strategies to overcome resistance to ICBs, cancer stem cell antigens and molecular markers, ongoing clinical trials for BCs and cancer vaccines for breast cancer.

The Enigma of Mammaglobin: Redefining the Biomarker Paradigm in Breast Carcinoma

The continuous evolution of cancer biology has led to the discovery of mammaglobin, a potential novel biomarker for breast carcinoma. This review aims to unravel the enigmatic aspects of mammaglobin and elucidate its potential role in redefining the paradigm of breast carcinoma biomarkers. We will thoroughly examine its expression in tumoral and peritumoral tissues and its circulating levels in the blood, thereby providing insights into its possible function in cancer progression and metastasis. Furthermore, the potential application of mammaglobin as a non-invasive diagnostic tool and a target for personalized treatment strategies will be discussed. Given the increasing incidence of breast carcinoma worldwide, the exploration of novel biomarkers such as mammaglobin is crucial in advancing our diagnostic capabilities and treatment modalities, ultimately contributing to improved patient outcomes.

Peptide-Based Vaccines in Clinical Phases and New Potential Therapeutic Targets as a New Approach for Breast Cancer: A Review

Breast cancer is the leading cause of death in women from 20 to 59 years old. The conventional treatment includes surgery, chemotherapy, hormonal therapy, and immunotherapy. This immunotherapy is based on administering monoclonal therapeutic antibodies (passive) or vaccines (active) with therapeutic purposes. Several types of vaccines could be used as potential treatments for cancer, including whole-cell, DNA, RNA, and peptide-based vaccines. Peptides used to develop vaccines are derived from tumor-associated antigens or tumor-specific antigens, such as HER-2, MUC1, ErbB2, CEA, FRα, MAGE A1, A3, and A10, NY-ESO-1, among others. Peptide-based vaccines provide some advantages, such as low cost, purity of the antigen, and the induction of humoral and cellular immune response. In this review, we explore the different types of vaccines against breast cancer with a specific focus on the description of peptide-based vaccines, their composition, immune response induction, and the description of new potential therapeutic targets.

Can Breast Implants Induce Breast Cancer Immunosurveillance? An Analysis of Antibody Response to Breast Cancer Antigen following Implant Placement

BACKGROUND

Women with cosmetic breast implants have significantly lower rates of subsequent breast cancer than the general population (relative risk, 0.63; 95 percent CI, 0.56 to 0.71). The authors hypothesize that breast implant-induced local inflammation stimulates immunosurveillance recognition of breast tumor antigen.

METHODS

Sera were collected from two cohorts of healthy women: women with long-term breast implants (i.e., breast implants for >6 months) and breast implant-naive women. Antibody responses to breast tumor antigens were tested by enzyme-linked immunosorbent assay and compared between cohorts by unpaired t test. Of the implant-naive cohort, nine women underwent breast augmentation, and antibody responses before and after implant placement were compared by paired t test.

RESULTS

Sera were collected from 104 women: 36 (34.6 percent) long-term breast implants and 68 (65.4 percent) implant-naive women. Women with long-term breast implants had higher antibody responses than implant-naive women to mammaglobin-A (optical density at 450 nm, 0.33 versus 0.22; p = 0.003) and mucin-1 (optical density at 450 nm, 0.42 versus 0.34; p = 0.02). There was no difference in antibody responses to breast cancer susceptibility gene 2, carcinoembryonic antigen, human epidermal growth factor receptor-2, or tetanus. Nine women with longitudinal samples preoperatively and 1 month postoperatively demonstrated significantly elevated antibody responses following implant placement to mammaglobin-A (mean difference, 0.13; p = 0.0002) and mucin-1 (mean difference 0.08; p = 0.02). There was no difference in postimplant responses to other breast tumor antigens, or tetanus.

CONCLUSIONS

Women with long-term breast implants have higher antibody recognition of mammaglobin-A and mucin-1. This study provides the first evidence of implant-related immune responses to breast cancer antigens.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Breast cancer vaccines delivered by dendritic cell-targeted lentivectors induce potent antitumor immune responses and protect mice from mammary tumor growth

Breast cancer immunotherapy is a potent treatment option, with antibody therapies such as trastuzumab increasing 2-year survival rates by 50%. However, active immunotherapy through vaccination has generally been clinically ineffective. One potential means of improving vaccine therapy is by delivering breast cancer antigens to dendritic cells (DCs) for enhanced antigen presentation. To accomplish this in vivo, we pseudotyped lentiviral vector (LV) vaccines with a modified Sindbis Virus glycoprotein so that they could deliver genes encoding the breast cancer antigen alpha-lactalbumin (Lalba) or erb-b2 receptor tyrosine kinase 2 (ERBB2 or HER2) directly to resident DCs. We hypothesized that utilizing these DC-targeting lentiviral vectors asa breast cancer vaccine could lead to an improved immune response against self-antigens found in breast cancer tumors. Indeed, single injections of the vaccine vectors were able to amplify antigen-specific CD8T cells 4-6-fold over naïve mice, similar to the best published vaccine regimens. Immunization of these mice completely inhibited tumor growth in a foreign antigen environment (LV-ERBB2 in wildtype mice), and it reduced the rate of tumor growth in a self-antigen environment (LV-Lalba in wildtype or LV-ERBB2 in MMTV-huHER2 transgenic). These results show that a single injection with targeted lentiviral vectors can be an effective immunotherapy for breast cancer. Furthermore, they could be combined with other immunotherapeutic regimens to improve outcomes for patients with breast cancer.

The Five Immune Forces Impacting DNA-Based Cancer Immunotherapeutic Strategy

DNA-based vaccine strategy is increasingly realized as a viable cancer treatment approach. Strategies to enhance immunogenicity utilizing tumor associated antigens have been investigated in several pre-clinical and clinical studies. The promising outcomes of these studies have suggested that DNA-based vaccines induce potent T-cell effector responses and at the same time cause only minimal side-effects to cancer patients. However, the immune evasive tumor microenvironment is still an important hindrance to a long-term vaccine success. Several options are currently under various stages of study to overcome immune inhibitory effect in tumor microenvironment. Some of these approaches include, but are not limited to, identification of neoantigens, mutanome studies, designing fusion plasmids, vaccine adjuvant modifications, and co-treatment with immune-checkpoint inhibitors. In this review, we follow a Porter’s analysis analogy, otherwise commonly used in business models, to analyze various immune-forces that determine the potential success and sustainable positive outcomes following DNA vaccination using non-viral tumor associated antigens in treatment against cancer.

Safety and preliminary evidence of biologic efficacy of a mammaglobin-a DNA vaccine in patients with stable metastatic breast cancer

PURPOSE

Mammaglobin-A (MAM-A) is overexpressed in 40% to 80% of primary breast cancers. We initiated a phase I clinical trial of a MAM-A DNA vaccine to evaluate its safety and biologic efficacy.

EXPERIMENTAL DESIGN

Patients with breast cancer with stable metastatic disease were eligible for enrollment. Safety was monitored with clinical and laboratory assessments. The CD8 T-cell response was measured by ELISPOT, flow cytometry, and cytotoxicity assays. Progression-free survival (PFS) was described using the Kaplan-Meier product limit estimator.

RESULTS

Fourteen subjects have been treated with the MAM-A DNA vaccine and no significant adverse events have been observed. Eight of 14 subjects were HLA-A2(+), and the CD8 T-cell response to vaccination was studied in detail. Flow cytometry demonstrated a significant increase in the frequency of MAM-A-specific CD8 T cells after vaccination (0.9% ± 0.5% vs. 3.8% ± 1.2%; P < 0.001), and ELISPOT analysis demonstrated an increase in the number of MAM-A-specific IFNγ-secreting T cells (41 ± 32 vs. 215 ± 67 spm; P < 0.001). Although this study was not powered to evaluate progression-free survival (PFS), preliminary evidence suggests that subjects treated with the MAM-A DNA vaccine had improved PFS compared with subjects who met all eligibility criteria, were enrolled in the trial, but were not vaccinated because of HLA phenotype.

CONCLUSION

The MAM-A DNA vaccine is safe, capable of eliciting MAM-A-specific CD8 T-cell responses, and preliminary evidence suggests improved PFS. Additional studies are required to define the potential of the MAM-A DNA vaccine for breast cancer prevention and/or therapy.

Current status of gene therapy for breast cancer: progress and challenges

Breast cancer is characterized by a series of genetic mutations and is therefore ideally placed for gene therapy intervention. The aim of gene therapy is to deliver a nucleic acid-based drug to either correct or destroy the cells harboring the genetic aberration. More recently, cancer gene therapy has evolved to also encompass delivery of RNA interference technologies, as well as cancer DNA vaccines. However, the bottleneck in creating such nucleic acid pharmaceuticals lies in the delivery. Deliverability of DNA is limited as it is prone to circulating nucleases; therefore, numerous strategies have been employed to aid with biological transport. This review will discuss some of the viral and nonviral approaches to breast cancer gene therapy, and present the findings of clinical trials of these therapies in breast cancer patients. Also detailed are some of the most recent developments in nonviral approaches to targeting in breast cancer gene therapy, including transcriptional control, and the development of recombinant, multifunctional bio-inspired systems. Lastly, DNA vaccines for breast cancer are documented, with comment on requirements for successful pharmaceutical product development.

Identification and translational validation of novel mammaglobin-A CD8 T cell epitopes

Mammaglobin-A (MAM-A) is a secretory protein that is overexpressed in 80 % of human breast cancers. Its near-universal expression in breast cancer as well as its exquisite tissue specificity makes it an attractive target for a breast cancer prevention vaccine, and we recently initiated a phase 1 clinical trial of a MAM-A DNA vaccine. Previously, we have identified multiple MAM-A CD8 T cell epitopes using a reverse immunology candidate epitope approach based on predicted binding, but to date no attempt has been made to identify epitopes using an unbiased approach. In this study, we used human T cells primed in vitro with autologous dendritic cells expressing MAM-A to systematically identify MAM-A CD8 T cell epitopes. Using this unbiased approach, we identified three novel HLA-A2-restricted MAM-A epitopes. CD8 T cells specific for these epitopes are able to recognize and lyse human breast cancer cells in a MAM-A-specific, HLA-A2-dependent fashion. HLA-A2(+)/MAM-A(+) breast cancer patients have an increased prevalence of CD8 T cells specific for these novel MAM-A epitopes, and vaccination with a MAM-A DNA vaccine significantly increases the number of these CD8 T cells. The identification and translational validation of novel MAM-A epitopes has important implications for the ongoing clinical development of vaccine strategies targeting MAM-A. The novel MAM-A epitopes represent attractive targets for epitope-based vaccination strategies, and can also be used to monitor immune responses. Taken together these studies provide additional support for MAM-A as an important therapeutic target for the prevention and treatment of breast cancer.

Mammaglobin B (SCGB2A1) is a novel tumour antigen highly differentially expressed in all major histological types of ovarian cancer: implications for ovarian cancer immunotherapy

Background:

We studied the genetic fingerprints of ovarian cancer and validated the potential of Mammaglobin b (SCGB2A1), one of the top differentially expressed genes found in our analysis, as a novel ovarian tumour rejection antigen.

Methods:

We profiled 70 ovarian carcinomas including 24 serous (OSPC), 15 clear-cell (CC), 24 endometrioid (EAC) and 7 poorly differentiated tumours, and 14 normal human ovarian surface epithelial (HOSE) control cell lines using the Human HG-U133 Plus 2.0 chip (Affymetrix). Quantitative real-time PCR and immunohistochemistry staining techniques were used to validate microarray data at RNA and protein levels for SCGB2A1. Full-length human-recombinant SCGB2A1 was used to pulse monocyte-derived dendritic cells (DCs) to stimulate autologous SCGB2A1-specific cytotoxic T-lymphocyte (CTL) responses against chemo-naive and chemo-resistant autologous ovarian tumours.

Results:

Gene expression profiling identified SCGB2A1 as a top differentially expressed gene in all histological ovarian cancer types tested. The CD8+ CTL populations generated against SCGB2A1 were able to consistently induce lysis of autologous primary (chemo-naive) and metastatic/recurrent (chemo-resistant) target tumour cells expressing SCGB2A1, whereas autologous HLA-identical noncancerous cells were not lysed. Cytotoxicity against autologous tumour cells was significantly inhibited by anti-HLA-class I (W6/32) monoclonal antibody. Intracellular cytokine expression measured by flow cytometry showed a striking type 1 cytokine profile (i.e., high IFN-γ secretion) in SCGB2A1-specific CTLs.

Conclusion:

SCGB2A1 is a top differentially expressed gene in all major histological types of ovarian cancers and may represent a novel and attractive target for the immunotherapy of patients harbouring recurrent disease resistant to chemotherapy.

Recombinant mammaglobin A adenovirus-infected dendritic cells induce mammaglobin A-specific CD8+ cytotoxic T lymphocytes against breast cancer cells in vitro

Mammaglobin A (MGBA) is a novel breast cancer-associated antigen almost exclusively over-expressed in primary and metastatic human breast cancers, making it a potential therapeutic target for breast cancer. The development of dendritic cell (DC)-induced tumor antigen specific CD8⁺ cytotoxic T lymphocytes (CTLs) may hold promise in cancer immunotherapy. In this study we constructed recombinant replication-defective adenoviral (Ad) vectors encoding MGBA and evaluated their ability to trigger anti-tumor immunity in vitro. DCs were isolated from the human peripheral blood monocyte cells (PBMCs) of two HLA-A33⁺ healthy female volunteers, and infected with adenovirus carrying MGBA cDNA (Ad-MGBA). After that, the Ad-MGBA-infected DCs were used to stimulate CD8⁺ CTLs in vitro and the latter was used for co-culture with breast cancer cell lines. The data revealed that infection with Ad-MGBA improved DC maturation and up-regulated the expression of co-stimulatory molecules and the secretion of interleukin-12 (IL-12), but down-regulated interleukin-10 (IL-10) secretion from DCs. Ad-MGBA-infected DC-stimulated CD8⁺CTLs displayed the highest cytotoxicity towards HLA-A33⁺/MGBA⁺ breast cancer MDA-MB-415 cells compared with other CD8⁺CTL populations, and compared with the cytotoxicity towards HLA-A33⁻/MGBA⁺ breast cancer HBL-100 cells and HLA-A33⁻/MGBA⁻ breast cancer MDA-MB 231 cells. In addition, Ad-MGBA-infected DC-stimulated CD8⁺ CTLs showed a high level of IFNγ secretion when stimulated with HLA-A33⁺/MGBA⁺ breast cancer MDA-MB-415 cells, but not when stimulated with HLA-A33⁻/MGBA⁺ HBL-100 and HLA-A33⁻/MGBA⁻MDA-MB-231 cells. In addition, killing of CD8⁺CTLs against breast cancer was in a major histocompability complex (MHC)-limited pattern. Finally, the data also determined the importance of TNF-α in activating DCs and T cells. These data together suggest that MGBA recombinant adenovirus-infected DCs could induce specific anti-tumor immunity against MGBA⁺ breast cancers, which could provide a novel strategy in the immunotherapy of breast cancer.

Adoptive transfer of Mammaglobin-A epitope specific CD8 T cells combined with a single low dose of total body irradiation eradicates breast tumors

Adoptive T cell therapy has proven to be beneficial in a number of tumor systems by targeting the relevant tumor antigen. The tumor antigen targeted in our model is Mammaglobin-A, expressed by approximately 80% of human breast tumors. Here we evaluated the use of adoptively transferred Mammaglobin-A specific CD8 T cells in combination with low dose irradiation to induce breast tumor rejection and prevent relapse. We show Mammaglobin-A specific CD8 T cells generated by DNA vaccination with all epitopes (Mammaglobin-A2.1, A2.2, A2.4 and A2.6) and full-length DNA in vivo resulted in heterogeneous T cell populations consisting of both effector and central memory CD8 T cell subsets. Adoptive transfer of spleen cells from all Mammaglobin-A2 immunized mice into tumor-bearing SCID/beige mice induced tumor regression but this anti-tumor response was not sustained long-term. Additionally, we demonstrate that only the adoptive transfer of Mammaglobin-A2 specific CD8 T cells in combination with a single low dose of irradiation prevents tumors from recurring. More importantly we show that this single dose of irradiation results in the down regulation of the macrophage scavenger receptor 1 on dendritic cells within the tumor and reduces lipid uptake by tumor resident dendritic cells potentially enabling the dendritic cells to present tumor antigen more efficiently and aid in tumor clearance. These data reveal the potential for adoptive transfer combined with a single low dose of total body irradiation as a suitable therapy for the treatment of established breast tumors and the prevention of tumor recurrence.

Mammaglobin-A cDNA vaccination of breast cancer patients induces antigen-specific cytotoxic CD4+ICOShi T cells

Mammaglobin-A (Mam-A) is a 10 kDa secretory protein that is overexpressed in 80 % of primary and metastatic human breast cancers. Previous studies from our laboratory demonstrated that Mam-A cDNA vaccine can induce Mam-A-specific CD8 T cell responses and mediate regression of human breast cancer xenografts in NOD/SCID mice. In this article, we present our results on a phase I clinical trial of a Mam-A cDNA vaccination in breast cancer patients with stage-IV metastatic disease, including the impact of vaccination on the expression of the inducible co-stimulator molecule (ICOS) on CD4 T cells. Specimens from seven patients with stage-IV metastatic cancer were available for these analyses. Patients were vaccinated with a Mam-A cDNA vaccine on days 0, 28, and 56, and immune responses were assessed at serial time points following vaccination. At 6 months following the first vaccination, flow cytometric analysis demonstrated a significant increase in the frequency of CD4+ICOS(hi) T cells from 5 ± 2 % pre-vaccination to 23 ± 4 % (p < 0.001), with a concomitant decrease in the frequency of CD4+FoxP3+ T cells (regulatory T cells [Treg]) from 19 ± 6 to 10 ± 5 % (p < 0.05). ELISpot analysis of CD4+ICOS(hi) sorted T cells demonstrated that following vaccination the cytokines produced by Mam-A-specific T cells switched from IL-10 (78 ± 21 spm pre-vaccination to 32 ± 14 spm 5 months post-vaccine p < 0.001) to IFN-γ (12 ± 6 spm pre-vaccination to 124 ± 31 spm 5 months post-vaccine p < 0.001). The ratio of CD4+ICOS(hi) T cells to CD4+FoxP3+ T cells increased from 0.37 ± 0.12 before vaccination to 2.3 ± 0.72 (p = 0.021) following vaccination. Further, these activated CD4+ICOS(hi) T cells induced preferential lysis of human breast cancer cells expressing Mam-A protein. We conclude that Mam-A cDNA vaccination is associated with specific expansion and activation of CD4+ICOS(hi) T cells, with a concomitant decrease in Treg frequency. These encouraging results strongly suggest that Mam-A cDNA vaccination can induce antitumor immunity in breast cancer patients.

Cancer genome sequencing and its implications for personalized cancer vaccines

New DNA sequencing platforms have revolutionized human genome sequencing. The dramatic advances in genome sequencing technologies predict that the $1,000 genome will become a reality within the next few years. Applied to cancer, the availability of cancer genome sequences permits real-time decision-making with the potential to affect diagnosis, prognosis, and treatment, and has opened the door towards personalized medicine. A promising strategy is the identification of mutated tumor antigens, and the design of personalized cancer vaccines. Supporting this notion are preliminary analyses of the epitope landscape in breast cancer suggesting that individual tumors express significant numbers of novel antigens to the immune system that can be specifically targeted through cancer vaccines.

Identification of HLA-A24-restricted CD8(+) cytotoxic T-cell epitopes derived from mammaglobin-A, a human breast cancer-associated antigen

Human breast cancer-associated antigen, mammaglobin-A (Mam-A), potentially offers a novel therapeutic target as a breast cancer vaccine. In this study, we define the CD8(+) cytotoxic T lymphocyte (CTL) response to Mam-A-derived candidate epitopes presented in the context of HLA-A24 (A*2402). HLA-A24 has a frequency of 72% in Japanese, 27% in Asian Indian, and 18% in Caucasian populations. Using a human leukocyte antigen (HLA)-binding prediction algorithm we identified 7 HLA-A24-restricted Mam-A-derived candidate epitopes (MAA24.1-7). Membrane stabilization studies with TAP-deficient T2 cells transfected with HLA-A2402 (T2.A24) indicated that MAA24.2 (CYAGSGCPL) and MAA24.4 (ETLSNVEVF) have the highest HLA-A24 binding affinity. Further, 2 CD8(+) CTL cell lines generated in vitro against T2.A24 cells individually loaded with Mam-A-derived candidate epitopes demonstrated significant cytotoxic activity against MAA24.2 and MAA24.4. In addition, the same CD8(+) CTL lines lysed the HLA-A24(+)/Mam-A(+) stable transfected human breast cancer cell lines AU565 and MDA-MB-361. However, these CTLs had no cytotoxicity against HLA-A24(-)/Mam-A(+) and HLA-A24(+)/Mam-A(-) breast cancer cell lines. In summary, our results define HLA-A24-restricted, Mam-A-derived, CD8(+) CTL epitopes that can potentially be employed for Mam-A-based breast cancer vaccine therapy to breast cancer patients with HLA-A24 phenotype.

Identification of immunodominant HLA-B7-restricted CD8+ cytotoxic T cell epitopes derived from mammaglobin-A expressed on human breast cancers

Mammaglobin-A (MGBA), a 10-kD protein, is over expressed in 80% of primary and metastatic human breast cancers. Breast cancer patients demonstrate high frequencies of CD8(+) cytotoxic T lymphocytes (CTL) specific to MGBA. Defining CD8(+) CTL responses to HLA class I-restricted MGBA-derived epitopes assumes significance in the context of our ongoing efforts to clinically translate vaccine strategies targeting MGBA for prevention and/or treatment of human breast cancers. In this study, we define the CD8(+) CTL response to MGBA-derived candidate epitopes presented in the context of HLA-B7, which has a frequency of 17.7% in Caucasian and 15.5% in African American populations. We identified seven MGBA-derived candidate epitopes with high predicted binding scores for HLA-B7 using a computer algorithm. Membrane stabilization studies with TAP-deficient T2 cells transfected with HLA-B7 indicated that MGBA B7.3 (VSKTEYKEL), B7.6 (KLLMVLMLA), B7.7 (NPQVSKTEY), and B7.1 (YAGSGCPLL) have the highest HLA-B7 binding affinities. Further, two CD8(+) CTL cell lines generated in vitro against T2.B7 cells individually loaded with MGBA-derived candidate epitopes showed significant cytotoxic activity against MGBA B7.1, B7.3, B7.6, and B7.7. In addition, the same CD8(+) CTL lines lysed the HLA-B7(+)/MGBA(+) human breast cancer cell line DU-4475 but had no significant cytotoxicity against HLA-B7(-) or MGBA(-) breast cancer cell lines. Cold-target inhibition studies strongly suggest that MGBA B7.3 is an immunodominant epitope. In summary, our results define HLA-B7-restriced, MGBA-derived, CD8(+) CTL epitopes with all of the necessary features for developing novel vaccine strategies against HLA-B7 expressing breast cancer patients.

Engineering superior DNA vaccines: MHC class I single chain trimers bypass antigen processing and enhance the immune response to low affinity antigens

It is commonly believed that delivery of antigen into the class I antigen presentation pathway is a limiting factor in the clinical translation of DNA vaccines. This is of particular concern in the context of cancer vaccine development as many immunodominant peptides derived from self tumor antigens are not processed and presented efficiently. To address this limitation, we have engineered completely assembled peptide/MHC class I complexes whereby all three components (class I heavy chain, beta(2)m, and peptide) are attached by flexible linkers and expressed as a single polypeptide (single chain trimers or SCT). In this study, we tested the efficacy of progressive generations of SCT DNA vaccines engineered to (1) enhance peptide binding, (2) enhance interaction with the CD8 coreceptor, and/or (3) activate CD4(+) helper T cells. Disulfide trap SCT (dtSCT) have been engineered to improve peptide binding, with mutations designed to create a disulfide bond between the class I heavy chain and the peptide linker. dtSCT DNA vaccines dramatically enhance the immune response to model low affinity antigens as measured by ELISPOT analysis and tumor challenge. SCT engineered to enhance interaction with the CD8 coreceptor have a higher affinity for the TCR/CD8 complex, and are associated with more robust CD8(+) T cell responses following vaccination. Finally, SCT constructs that coexpress a universal helper epitope PADRE, dramatically enhance CD8(+) T cell responses. Taken together, our data demonstrate that dtSCT DNA vaccines coexpressing a universal CD4 epitope are highly effective in generating immune responses to poorly processed and presented cancer antigens.

Oleanolic Acid, a plant triterpenoid, significantly improves survival and function of islet allograft

BACKGROUND.: Oleanolic acid (OA) is a ubiquitous triterpenoid, with potent antioxidant and anti-inflammatory properties. Here, we tested whether these combined properties of OA can prevent nonimmunologic primary nonfunctioning and immunologic phenomena ascribed to graft rejection hence prolong islet allograft survival. METHODS.: Islet transplants were performed under kidney capsule of streptozotocin-induced diabetic C57BL/6 mice with BALB/c islets. Recipients were treated with 0.5 mg/day of OA intraperitoneally, and serum samples were collected once in 2 days and used for luminex, ELISA, and donor-specific antibody screening. Transplanted mice were killed at different time intervals to obtain splenocytes and kidney samples for ELISPOT, mixed leukocyte reaction, and immunohistochemical studies. RESULTS.: After transplantation, the decrement of blood glucose was significantly faster in mice receiving OA less than 2+/-1 days compared with untreated (4+/-2 days). OA prolonged survival of transplanted islets up to 23+/-3 days and reversed diabetes even with 250 islets. Treatment group showed increased serum interleukin (IL)-10 (twofold) and decreased inducible protein-10 and IL-4 (threefold) in luminex. Significantly reduced frequency of interferon-gamma (4.5-fold), IL-4 (3.5-fold), IL-2 (2.3-fold), and IL-17 (fourfold) producing T-cell populations were found in ELISPOT. OA-treated grafts had significant reduced and delayed infiltration of CD4+ and CD8+ T cells. OA also delayed donor-specific antibody generation up to 19 days after transplantation. Combined treatment with cyclosporine A, OA further prolonged the islet allograft survival to 34+/-3 days. CONCLUSIONS.: In conclusion, OA is an attractive, dietary nontoxic plant triterpenoid, which suppresses the production of proinflammatory cytokines and delays graft-specific immune responses to prolong islet allograft survival.

Malignant neoplasm in the axilla of a male: suspected primary carcinoma of an accessory mammary gland

A 58-year-old Japanese male patient visited our hospital for evaluation of an elastic hard mass, measuring 80 x 50 mm, in the right axillary area. Incisional biopsy for suspected malignancy was performed, and histopathologic examination by hematoxylin-eosin (H&E) staining yielded a diagnosis of poorly differentiated adenocarcinoma metastatic from an unknown primary. As the tumor was immunohistochemically positive for both ER and PgR, metastatic breast cancer was strongly suspected. Ultrasonography, CT, and MRI revealed no evidence of tumors in the bilateral mammary glands. Detailed examination of the head and neck region, lung, and upper and lower gastrointestinal tract also revealed no evidence of a primary tumor. After chemotherapy, the patient underwent tumor resection with axillary lymph node dissection. On the basis of the histological features of H&E-stained specimens and immunohistochemistry of the resected tumor, this case was diagnosed as breast cancer of unknown origin in a male. The tumor could have been an axillary lymph node metastasis from an occult breast carcinoma, or primary cancer arising in an accessory mammary gland.

Prognostic value of the molecular detection of circulating tumor cells using a multimarker reverse transcription-PCR assay for cytokeratin 19, mammaglobin A, and HER2 in early breast cancer

PURPOSE

To investigate the prognostic value of the molecular detection of circulating tumor cells (CTCs) using three markers [cytokeratin 19 (CK19), mammaglobin A (MGB1), and HER2] in early breast cancer.

EXPERIMENTAL DESIGN

CK19mRNA+, MGB1mRNA+, and HER2mRNA+ cells were detected using real-time (CK19) and nested (MGB1 and HER2) reverse transcription-PCR in the peripheral blood of 175 women with stage I to III breast cancer before the initiation of adjuvant chemotherapy. The detection of CTCs was correlated with clinical outcome. In 10 patients, immunofluorescence staining experiments were done to investigate the coexpression of cytokeratin, MGB1, and HER2 in CTCs.

RESULTS

CK19mRNA+, MGB1mRNA+, and HER2mRNA+ cells were detected in 41.1%, 8%, and 28.6% of the 175 patients, respectively. Patients had one of the following molecular profiles: CK19mRNA+/MGB1mRNA+/HER2mRNA+ (n = 8), CK19mRNA+/MGB1mRNA+/HER2mRNA- (n = 1), CK19mRNA+/MGB1mRNA-/HER2mRNA+ (n = 42), CK19mRNA+/MGB1mRNA-/HER2mRNA- (n = 21), CK19mRNA-/MGB1mRNA+/HER2mRNA- (n = 5), and CK19mRNA-/MGB1mRNA-/HER2mRNA- (n = 98). Double-immunofluorescence experiments confirmed the following CTC phenotypes: CK+/MGB1+, CK+/MGB1-, CK-/MGB1+, CK+/HER2+, CK+/HER2-, MGB1+/HER2-, and MGB1+/HER2+. In univariate analysis, the detection of CK19mRNA+, MGB1mRNA+, and HER2mRNA+ cells was associated with shorter disease-free survival (DFS; P < 0.001, P = 0.001, and P < 0.001, respectively), whereas the detection of CK19mRNA+ and MGB1mRNA+ cells was associated with worse overall survival (P = 0.044 and 0.034, respectively). In multivariate analysis, estrogen receptor-negative tumors and the detection of CK19mRNA+ and MGB1mRNA+ cells were independently associated with worse DFS.

CONCLUSION

The detection of peripheral blood CK19mRNA+ and MGB1mRNA+ cells before adjuvant chemotherapy predicts poor DFS in women with early breast cancer.

Use of a panel of novel genes for differentiating breast cancer from non-breast tissues

Existing serum markers for breast cancer such as CA 15-3, BR 27.29 and CEA lack sensitivity and specificity. The aim of this study was to evaluate the value of new putative breast-specific markers for differentiating breast cancer from non-breast tissues. Expression of mammaglobin A (MGA), B726P, small breast epithelial mucin (SBEM) and MUC1 was measured by RT-PCR. MGA mRNA was detected in 86/162 (60%) breast cancers but in only 1/32 (3%) non-breast tissues; B726P was detected in 44/108 (41%) breast cancers but in none of 20 non-breast tissues, while SBEM was present in 52/103 (51%) breast cancers but in only 1/26 non-breast cancer tissues. In contrast to these novel markers, the established breast cancer marker MUC1 was detected in 72/99 (73%) breast cancers and in 22/32 (59%) of non-breast tissues. Combining MGA with B726P separated breast cancer from non-breast tissue with a sensitivity of 71% and a specificity of 95% while combining MGA with SBEM differentiated breast cancer from non-breast tissues with a sensitivity of 76% and a specificity of 89%. Genes such as MGA, B726P and SBEM that are expressed relatively exclusively in breast tissue are potential new markers for breast cancer.

Breast cancer vaccines: promise for the future or pipe dream?

The objective of this study was to review issues involved in the search for a breast cancer vaccine. A review of the recent literature (2004-2007) was undertaken, with earlier literature included as appropriate for background, to assess 1) current approaches being used to create a therapeutic breast cancer vaccine, and 2) potential strategies for a preventive vaccine targeting either an infectious agent or tumor-associated antigen. Several approaches to the development of a therapeutic vaccine show promise, including tumor cell/dendritic cell fusion and DNA vaccines based on single purified antigens or DNA fragments from whole cells. Most of these experimental vaccines have either not moved beyond preclinical testing or have not shown a significant clinical response. Strategies involving host factors that mitigate immune response against tumors also show promise. Interest has increased in developing a preventive vaccine that can be administered to immunocompetent patients with minimal or no evidence of disease. Prophylactic vaccines typically target infectious agents, but the evidence for an infectious etiology for breast cancer is largely descriptive and difficult to interpret. A second strategy for a preventive breast cancer vaccine is to target tumor-associated antigens. Ongoing clinical trials are utilizing this approach, with preliminary results that are encouraging.

Characterization of the role of CD8+T cells in breast cancer immunity following mammaglobin-A DNA vaccination using HLA-class-I tetramers

INTRODUCTION

Mammaglobin-A(mam-A) is expressed in over 80% of human breast tumors. We recently reported that mam-A DNA vaccination resulted in breast cancer immunity in a preclinical model. Here we investigated whether mam-A HLA-class-I tetramers could be used to monitor and define the role of CD8(+)cytotoxic T-lymphocytes(CTL) in mediating breast cancer immunity following mam-A DNA vaccination.

STUDY DESIGN

Mam-A DNA vaccination was performed in HLA-A2(+)huCD8(+ )transgenic mice. HLA-A2 tetramers carrying the immunodominant mamA2.1 peptide were used to monitor CD8(+)CTL. Human breast cancer colonies were developed in immunodeficient SCID-beige mice. ELISPOT was used to correlate frequency of mamA2.1 tetramer(+)CD8(+)T cells and IFN-gamma production [spots per million cells (spm)] in human subjects.

RESULTS

Vaccination of HLA-A2(+)huCD8(+) mice with mam-A DNA vaccine, but not empty vector, led to the expansion of mamA2.1 tetramer(+)CD8(+)T-cells in peripheral blood (<0.5% pre-vaccination compared to >2.0% post-vaccination). CD8(+)T cells from vaccinated mice specifically lysed UACC-812(HLA-A2(+)/mam-A(+), 25% lysis) but not MDA-MB-415(HLA-A2(-)/mam-A(+)) or MCF-7(HLA-A2(+)/mam-A(-)) breast cancer cells. Adoptive transfer of purified CD8(+)T cells from vaccinated mice into immunodeficient SCID-beige mice with established human breast cancer colonies led to tetramer(+)CD8(+ )T-cell infiltration with regression of UACC-812 but not MCF-7 tumors. HLA-A2(+) breast cancer patients revealed increased frequency of mamA2.1 tetramer(+)CD8(+ )T-cells compared to normal controls (2.86 +/- 0.8% vs. 0.71 +/- 0.1%, P = 0.01) that correlated with the IFN-gamma response to mamA2.1 peptide (48.1 +/- 20.9 vs. 2.9 +/- 0.8 spm, P = 0.03).

CONCLUSIONS

CD8(+ )T-cells are crucial in mediating breast cancer immunity following mam-A DNA vaccination. Mam-A HLA-class-I tetramers can be effectively used to monitor development of CD8(+ )T-cells following mam-A vaccination.

Generation of mammaglobin-A-specific CD4 T cells and identification of candidate CD4 epitopes for breast cancer vaccine strategies

BACKGROUND

Mammaglobin-A (MGB) is a breast cancer-associated antigen that is an attractive target for immune intervention. MGB has been shown to induce a specific CD8 T cell response in breast cancer patients, but little is known about a possible MGB-specific CD4 T cell response.

METHODS

Peripheral blood-derived CD4(+)CD25(-) T cells were stimulated in vitro with MGB-pulsed antigen-presenting cells (APC). The MGB and human leukocyte antigen (HLA) class II specificity of the CD4 T cell lines was confirmed by cytokine release following restimulation with autologous and allogenic APC pulsed with MGB from different sources. Candidate HLA class II-restricted epitopes were identified by computer algorithm and validated in cytokine release assays.

RESULTS

MGB-specific CD4 T cells were successfully generated in cultures from six of seven donors. Restimulation of MGB-specific CD4 T cells with MGB-pulsed APC induced significantly higher levels of interferon (IFN)-gamma release than APC pulsed with an irrelevant protein (P = 0.0004). Cultures from five of seven donors showed a pure Th1 type response as evidenced by the absence of interleukin (IL)-4. MGB-specific CD4 T cells recognized both recombinant and naturally processed MGB presented by APC. This recognition was HLA class II-restricted, as HLA-DR mismatched APC were not recognized. MGB-specific CD4 T cells from three of four donors recognized MGB-derived, HLA class II-restricted peptides pulsed onto APC.

CONCLUSIONS

We have successfully generated MGB-specific CD4 T cell cultures and identified candidate MGB HLA class II epitopes. These studies should facilitate study of the CD4 T cell response to MGB, and the development and monitoring of vaccine strategies targeting this unique antigen.

Multidisciplinary frontiers in breast cancer management: a surgeon's perspective

The current paradigm of breast cancer management may be altered significantly over the coming years by the adoption of new treatment schema and devices outside of the surgical arena. New advances in breast cancer imaging will improve our ability to detect early-stage disease but also will assist in monitoring treatment outcomes and support the development of nonsurgical ablation techniques. These advances, some already in use, include a 3-dimensional adaptation of digital mammography, color Doppler ultrasonography that can visualize neovascularization in growing tumors, contrast-enhanced magnetic resonance imaging with improved accuracy for the detection of occult cancers, a specialized approach to positron emission tomography designed for use on the breast, and the development of nanoparticle contrast agents that can be visualized with near-infrared light. Systemic therapy, which revolutionized breast cancer management in the last half of the 20th century, is being reconceptualized, with attention turning to adjusting the timing of chemotherapy. Dose-dense regimens are being tested, and there also is interest in so-called metronomic chemotherapy in which very low doses are given on a very frequent schedule, resulting in reduced toxicity and treatment outcomes that reflect an antiangiogenic mode of action. Finally, the possibility of a breast cancer vaccine continues to intrigue and excite physicians and patients alike, with the promise of enlisting the body's own immune system to seek out and destroy cancer cells and/or prevent the development of future disease. It will be important for surgeons to stay aware of all developments that may improve the care of their patients and to be true surgical oncologists rather than merely surgical technicians.

Expression analysis of mammaglobin A (SCGB2A2) and lipophilin B (SCGB1D2) in more than 300 human tumors and matching normal tissues reveals their co-expression in gynecologic malignancies

BACKGROUND

Mammaglobin A (SCGB2A2) and lipophilin B (SCGB1D2), two members of the secretoglobin superfamily, are known to be co-expressed in breast cancer, where their proteins form a covalent complex. Based on the relatively high tissue-specific expression pattern, it has been proposed that the mammaglobin A protein and/or its complex with lipophilin B could be used in breast cancer diagnosis and treatment. In view of these clinical implications, the aim of the present study was to analyze the expression of both genes in a large panel of human solid tumors (n = 309), corresponding normal tissues (n = 309) and cell lines (n = 11), in order to evaluate their tissue specific expression and co-expression pattern.

METHODS

For gene and protein expression analyses, northern blot, dot blot hybridization of matched tumor/normal arrays (cancer profiling arrays), quantitative RT-PCR, non-radioisotopic RNA in situ hybridization and immunohistochemistry were used.

RESULTS

Cancer profiling array data demonstrated that mammaglobin A and lipophilin B expression is not restricted to normal and malignant breast tissue. Both genes were abundantly expressed in tumors of the female genital tract, i.e. endometrial, ovarian and cervical cancer. In these four tissues the expression pattern of mammaglobin A and lipophilin B was highly concordant, with both genes being down-, up- or not regulated in the same tissue samples. In breast tissue, mammaglobin A expression was down-regulated in 49% and up-regulated in 12% of breast tumor specimens compared with matching normal tissues, while lipophilin B was down-regulated in 59% and up-regulated in 3% of cases. In endometrial tissue, expression of mammaglobin A and lipophilin B was clearly up-regulated in tumors (47% and 49% respectively). Both genes exhibited down-regulation in 22% of endometrial tumors. The only exceptions to this concordance of mammaglobin A/lipophilin B expression were normal and malignant tissues of prostate and kidney, where only lipophilin B was abundantly expressed and mammaglobin A was entirely absent. RNA in situ hybridization and immunohistochemistry confirmed expression of mammaglobin A on a cellular level in endometrial and cervical cancer and their corresponding normal tissues.

CONCLUSION

Altogether, these data suggest that expression of mammaglobin A and lipophilin B might be controlled in different tissues by the same regulatory transcriptional mechanisms. Diagnostic assays based on mammaglobin A expression and/or the mammaglobin A/lipophilin B complex appear to be less specific for breast cancer, but with a broader spectrum of potential applications, which includes gynecologic malignancies.

Innate Anti-breast Cancer Immunity of Apoptosis-resistant Human γδ-T cells

We previously identified a CD2-initiated signaling pathway which inhibits activation-induced cell death in mitogen-stimulated human gammadelta-T cells permitting the large-scale expansion of these cells. Here we report the innate anti-tumor activity of expanded human gammadelta-T cells against human breast cancer cells. Apoptosis-resistant human gammadelta-T cells which were expanded in vitro from cultured human peripheral blood mononuclear cells displayed lytic activity against breast cancer cell lines MDA-MB-231, MCF-7 and T-47D, but failed to kill normal human skin fibroblasts and normal human liver cells. Monoclonal antibodies (mAb) directed against the gammadelta-T cell receptor (TCR) or mAb directed against either the Vgamma9 or the Vdelta2 TCR chains were able to block gammadelta-T cell-mediated lysis of MDA-MB-231 cells. In addition, mAb against intercellular adhesion molecules-1 (ICAM-1/CD54) or CD18 (beta subunit of ICAM-1 counter-receptor) also blocked gammadelta-T cell-mediated killing of MDA-MB-231 cells. Ex vivo expanded human gammadelta-T cells are thus able to innately recognize and kill human breast cancer cells in a gammadelta-TCR-dependent manner; ICAM-1 and CD18 also appear to be involved in the interactions between sensitive breast cancer cells and cytolytic gammadelta-T cells. As apoptosis-resistant human gammadelta-T cells can now readily be expanded to large numbers (clinical scale), these findings must be considered in the context of developing adoptive immunotherapy strategies to exploit gammadelta-T cell innate immune responses for the primary or adjuvant treatment of breast cancer.

Tat mammaglobin fusion protein transduced dendritic cells stimulate mammaglobin-specific CD4 and CD8 T cells

Proteins can be efficiently introduced into cells when fused to a protein transduction domain, such as Tat from the human immunodeficiency virus. We recently reported that dendritic cells transduced with a Tat fusion protein containing the extracellular domain of Her2/neu (Tat-Her2/neu) induced CD8 cytotoxic T lymphocytes (CTL) that specifically lysed Her2/neu-expressing breast and ovarian cancer cells. In the current study we further investigated the mechanism of protein transduction, utilizing the breast cancer-associated protein, mammaglobin-A, which is expressed in about 80% of breast cancers. Using a Tat-mammaglobin fusion protein, we tested the ability of Tat-mammaglobin transduced dendritic cells to stimulate antigen-specific CD4 and CD8 T cells. Low levels of serum considerably improved protein transduction as determined by Western blot, and also improved presentation of antigenic peptide as evidenced by functional studies using antigen-specific T cells. Confocal microscope analyses of antigen-presenting cells (APC) incubated with Tat-mammaglobin showed localized distribution in addition to diffuse distribution in the cytosol. In contrast, mammaglobin lacking Tat showed only a localized distribution. Simultaneous incubation with both proteins resulted in overlapping localized distributions, suggesting Tat fusion proteins are processed through both the MHC class I and class II pathways. Indeed, stimulation of T cells with Tat-mammaglobin transduced dendritic cells led to an expansion of mammaglobin-specific CD4 T helper-1 lymphocytes along with CD8 CTL. We conclude that Tat-mammaglobin transduced dendritic cells can induce both CD4 and CD8 mammaglobin-specific T cells. These findings could be further exploited for the development of a mammaglobin-based vaccine for breast cancer.