Active immunotherapy in HER2 overexpressing breast cancer: current status and future perspectives

Direct competitive assay for HER2 detection in human plasma using Bloch surface wave-based biosensors

The overexpression and/or amplification of the HER2/neu oncogene has been proposed as a prognostic marker in breast cancer. The detection of the related peptide HER2 remains a grand challenge in cancer diagnosis and for therapeutic decision-making. Here, we used a biosensing device based on Bloch Surface Waves excited on a one-dimensional photonic crystal (1DPC) as valid alternative to standard techniques. The 1DPC was optimized to operate in the visible spectrum and the biosensor optics has been designed to combine label-free and fluorescence operation modes. This feature enables a real-time monitoring of a direct competitive assay using detection mAbs conjugated with quantum dots for an accurate discrimination in fluorescence mode between HER2-positive/negative human plasma samples. Such a competitive assay was implemented using patterned alternating areas where HER2-Fc chimera and reference molecules were bio-conjugated and monitored in a multiplexed way. By combining Label-Free and fluorescence detection analysis, we were able to tune the parameters of the assay and provide an HER2 detection in human plasma in less than 20 min, allowing for a cost-effective assay and rapid turnaround time. The proposed approach offers a promising technique capable of performing combined label-free and fluorescence detection for both diagnosis and therapeutic monitoring of diseases.

Breast cancer vaccination: Latest advances with an analytical focus on clinical trials

Breast cancer (BC) is one of the main causes of cancer-related death worldwide. The heterogenicity of breast tumors and the presence of tumor resistance, metastasis, and disease recurrence make BC a challenging malignancy. A new age in cancer treatment is being ushered in by the enormous success of cancer immunotherapy, and therapeutic cancer vaccination is one such area of research. Nevertheless, it has been shown that the application of cancer vaccines in BC as monotherapy could not induce satisfying anti-tumor immunity. Indeed, the application of various vaccine platforms as well as combination therapies like immunotherapy could influence the clinical benefits of BC treatment. We analyzed the clinical trials of BC vaccination and revealed that the majority of trials were in phase I and II meaning that the BC vaccine studies lack favorable outcomes or they need more development. Furthermore, peptide- and cell-based vaccines are the major platforms utilized in clinical trials according to our analysis. Besides, some studies showed satisfying outcomes regarding carbohydrate-based vaccines in BC treatment. Recent advancements in therapeutic vaccines for breast cancer were promising strategies that could be accessible in the near future.

Immunotherapy for HER-2 positive breast cancer

Immunotherapy is a developing treatment for advanced breast cancer. Immunotherapy has clinical significance for the treatment of triple-negative breast cancers and human epidermal growth factor receptor-2 positive (HER2+) breast cancers. As a proved effective passive immunotherapy, clinical application of the monoclonal antibodies trastuzumab, pertuzumab and T-DM1 (ado-trastuzumab emtansine) has significantly improved the survival of patients with HER2+ breast cancers. Immune checkpoint inhibitors that block programmed death receptor-1 and its ligand (PD-1/PD-L1) have also shown benefits for breast cancer in various clinical trials. Adoptive T-cell immunotherapies and tumor vaccines are emerging as novel approaches to treating breast cancer, but require further study. This article reviews recent advances in immunotherapy for HER2+ breast cancers.

Chimeric immune checkpoint protein vaccines inhibit the tumorigenesis and growth of rat cholangiocarcinoma

Cholangiocarcinoma (CCA) is the second most common primary liver malignancy and carries a dismal prognosis due to difficulties in achieving an optimal resection, and poor response to current standard-of-care systemic therapies. We previously devised a CTLA4-PD-L1 DNA cancer vaccine (DNA vaccine) and demonstrated its therapeutic effects on reducing tumor growth in a thioacetamide (TAA)-induced rat intrahepatic CCA (iCCA) model. Here, we developed a CTLA4-PD-L1 chimeric protein vaccine (Protein vaccine), and examined its effects in the rat iCCA model. In a therapeutic setting, iCCA-bearing rats received either DNA plus Protein vaccines or Protein vaccine alone, resulting in increased PD-L1 and CTLA-4 antibody titers, and reduced iCCA tumor burden as verified by animal positron emission tomography (PET) scans. Treating iCCA-bearing rats with Protein vaccine alone led to the increase of CTAL4 antibody titers that correlated with the decrease of tumor SUV ratio, indicating regressed tumor burden, along with increased CD8 and granzyme A (GZMA) expression, and decreased PD-L1 expression on tumor cells. In a preventive setting, DNA or Protein vaccines were injected in rats before the induction of iCCA by TAA. Protein vaccines induced a more sustained PD-L1 and CTLA-4 antibody titers compared with DNA vaccines, and was more potent in preventing iCCA tumorigenesis. Correspondingly, Protein vaccines, but not DNA vaccines, downregulated PD-L1 gene expression and hindered the carcinogenesis of iCCA. Taken together, the CTLA4-PD-L1 chimeric protein vaccine may function both as a therapeutic cancer vaccine and as a preventive cancer vaccine in the TAA-induced iCCA rat model.

Prevention and Therapy of Metastatic HER-2+ Mammary Carcinoma with a Human Candidate HER-2 Virus-like Particle Vaccine

Vaccines are a promising therapeutic alternative to monoclonal antibodies against HER-2+ breast cancer. We present the preclinical activity of an ES2B-C001, a VLP-based vaccine being developed for human breast cancer therapy. FVB mice challenged with HER-2+ mammary carcinoma cells QD developed progressive tumors, whereas all mice vaccinated with ES2B-C001+Montanide ISA 51, and 70% of mice vaccinated without adjuvant, remained tumor-free. ES2B-C001 completely inhibited lung metastases in mice challenged intravenously. HER-2 transgenic Delta16 mice developed mammary carcinomas by 4−8 months of age; two administrations of ES2B-C001+Montanide prevented tumor onset for >1 year. Young Delta16 mice challenged intravenously with QD cells developed a mean of 68 lung nodules in 13 weeks, whereas all mice vaccinated with ES2B-C001+Montanide, and 73% of mice vaccinated without adjuvant, remained metastasis-free. ES2B-C001 in adjuvant elicited strong anti-HER-2 antibody responses comprising all Ig isotypes; titers ranging from 1−10 mg/mL persisted for many months. Antibodies inhibited the 3D growth of human HER-2+ trastuzumab-sensitive and -resistant breast cancer cells. Vaccination did not induce cytokine storms; however, it increased the ELISpot frequency of IFN-γ secreting HER-2-specific splenocytes. ES2B-C001 is a promising candidate vaccine for the therapy of tumors expressing HER-2. Preclinical results warrant further development towards human clinical studies.

Current Molecular Combination Therapies Used for the Treatment of Breast Cancer

Breast cancer is the second leading cause of death for women worldwide. While monotherapy (single agent) treatments have been used for many years, they are not always effective, and many patients relapse after initial treatment. Moreover, in some patients the response to therapy becomes weaker, or resistance to monotherapy develops over time. This is especially problematic for metastatic breast cancer or triple-negative breast cancer. Recently, combination therapies (in which two or more drugs are used to target two or more pathways) have emerged as promising new treatment options. Combination therapies are often more effective than monotherapies and demonstrate lower levels of toxicity during long-term treatment. In this review, we provide a comprehensive overview of current combination therapies, including molecular-targeted therapy, hormone therapy, immunotherapy, and chemotherapy. We also describe the molecular basis of breast cancer and the various treatment options for different breast cancer subtypes. While combination therapies are promising, we also discuss some of the challenges. Despite these challenges, the use of innovative combination therapy holds great promise compared with traditional monotherapies. In addition, the use of multidisciplinary technologies (such as nanotechnology and computer technology) has the potential to optimize combination therapies even further.

Breast cancer vaccines: New insights into immunomodulatory and nano-therapeutic approaches

Breast cancer (BC) is known to be a highly heterogeneous disease that is clinically subdivided into four primary molecular subtypes, each having distinct morphology and clinical implications. These subtypes are principally defined by hormone receptors and other proteins involved (or not involved) in BC development. BC therapeutic vaccines [including peptide-based vaccines, protein-based vaccines, nucleic acid-based vaccines (DNA/RNA vaccines), bacterial/viral-based vaccines, and different immune cell-based vaccines] have emerged as an appealing class of cancer immunotherapeutics when used alone or combined with other immunotherapies. Employing the immune system to eliminate BC cells is a novel therapeutic modality. The benefit of active immunotherapies is that they develop protection against neoplastic tissue and readjust the immune system to an anti-tumor monitoring state. Such immunovaccines have not yet shown effectiveness for BC treatment in clinical trials. In recent years, nanomedicines have opened new windows to increase the effectiveness of vaccinations to treat BC. In this context, some nanoplatforms have been designed to efficiently deliver molecular, cellular, or subcellular vaccines to BC cells, increasing the efficacy and persistence of anti-tumor immunity while minimizing undesirable side effects. Immunostimulatory nano-adjuvants, liposomal-based vaccines, polymeric vaccines, virus-like particles, lipid/calcium/phosphate nanoparticles, chitosan-derived nanostructures, porous silicon microparticles, and selenium nanoparticles are among the newly designed nanostructures that have been used to facilitate antigen internalization and presentation by antigen-presenting cells, increase antigen stability, enhance vaccine antigenicity and remedial effectivity, promote antigen escape from the endosome, improve cytotoxic T lymphocyte responses, and produce humoral immune responses in BC cells. Here, we summarized the existing subtypes of BC and shed light on immunomodulatory and nano-therapeutic strategies for BC vaccination. Finally, we reviewed ongoing clinical trials on BC vaccination and highlighted near-term opportunities for moving forward.

Gene Gun Her2/neu DNA Vaccination: Evaluation of Vaccine Efficacy in a Syngeneic Her2/neu Mouse Tumor Model

Genetic vaccination using naked plasmid DNA is an immunization strategy both against infectious diseases and cancer.In order to improve efficacy of DNA vaccines, particularly in large animals and humans, different strategies have been pursued. These vaccination strategies are based on different application routes, schedules and coexpression of immunomodulatory molecules as adjuvants. Our mouse tumor model offers the possibility to investigate Her2/neu DNA vaccines in different settings, that is, intramuscular or intradermal application with or without coexpression of adjuvants. The immunogenicity of predicted peptides for Her2/neu specific memory T cells were screened and confirmed after intramuscular and intradermal application. Protection from tumor growth in tumor challenge experiments and both T cell and humoral immune responses against Her2/neu peptides are used as surrogate parameters for vaccine efficacy.

Potent anti-tumor immune response and tumor growth inhibition induced by HER2 subdomain fusion protein in a mouse tumor model

PURPOSE

Several approaches have so far been employed to establish anti-tumor immunity by targeting HER2 protein. Active immunization with recombinant HER2 subdomains has previously been demonstrated to induce potent immune response and tumor growth inhibition. In the present study, we investigated the immunogenicity and tumor inhibitory effect of a fusion protein consisting of human HER2 extracellular subdomain (ECD-DI + II) together with T-helper cell epitopes of Tetanus toxin (p2 and p30).

METHODS

BALB/c mice were immunized with two recombinant proteins (DI + II and p2p30-DI + II) emulsified in 4 different adjuvants. Anti-DI + II antibody response, cytokine profile, frequency of splenic CD25⁺FOXP3⁺ regulatory T cells (Tregs) and CD8⁺CD107a⁺ cytotoxic T lymphocytes (CTLs) were assessed in the immunized mice. To assess the anti-tumor effect, the immunized mice were subcutaneously challenged with HER2-overexpressing tumor cells and the tumor growth was determined.

RESULTS

Both recombinant proteins were able to induce comparable levels of ECD-DI + II-specific antibodies. Immunization with p2p30-DI + II resulted in a significant increase in the level of Interferon-gamma (IFN-γ) secretion compared to DI + II protein and significantly higher frequency of CTLs and lower frequency of Tregs. The number of mice that remained tumor-free until day 120 was significantly higher in p2p30-DI + II vaccinated groups.

CONCLUSIONS

Our data suggest that the p2p30-DI + II fusion protein together with CpG adjuvant induces more potent anti-tumor immune responses in a mouse tumor model. Accordingly, this formulation might be considered as a potential immunotherapeutic approach in HER2⁺ cancers.

Breast Cancer Vaccines: Disappointing or Promising?

Breast cancer has become the most commonly diagnosed cancer globally. The relapse and metastasis of breast cancer remain a great challenge despite advances in chemotherapy, endocrine therapy, and HER2 targeted therapy in the past decades. Innovative therapeutic strategies are still critically in need. Cancer vaccine is an attractive option as it aims to induce a durable immunologic response to eradicate tumor cells. Different types of breast cancer vaccines have been evaluated in clinical trials, but none has led to significant benefits. Despite the disappointing results at present, new promise from the latest study indicates the possibility of applying vaccines in combination with anti-HER2 monoclonal antibodies or immune checkpoint blockade. This review summarizes the principles and mechanisms underlying breast cancer vaccines, recapitulates the type and administration routes of vaccine, reviews the current results of relevant clinical trials, and addresses the potential reasons for the setbacks and future directions to explore.

The management of HER2-positive early breast cancer: Current and future therapies

Advances in human epidermal growth factor receptor 2 (HER2)-directed therapies have revolutionised the care of patients with HER2-positive breast cancer. While adjuvant trastuzumab in combination with chemotherapy has dramatically improved the prognosis for patients with early-stage disease, up to a quarter of patients will develop recurrent disease. The standard-of-care treatment paradigm has evolved with the introduction of newer HER2-directed therapies and increasing use of neoadjuvant systemic therapy, the latter providing us with important functional data to HER2-directed therapies and impacting subsequent adjuvant therapy decisions. However, these new strategies come at a cost of increased toxicity and economic burden, and only a subset of patients benefit from such approaches. Thus, ongoing work is required to identify predictive biomarkers of response, to de-escalate treatment in patients who may do just as well with less therapy, and new therapeutic approaches for patients who do not respond to currently used therapies. In this review, we will examine the current therapeutic landscape, summarise the latest evidence, and list the current treatment algorithms for early stage HER2-positive breast cancer.

Prognostic Biomarker-Based Identification of Drugs for Managing the Treatment of Endometrial Cancer

INTRODUCTION

Uterine corpus endometrial carcinoma (UCEC) causes thousands of deaths per year. To improve the overall survival of patients with UCEC, there is a need to identify prognostic biomarkers and potential drugs.

OBJECTIVES

The aim of this study was twofold: the identification of prognostic gene signatures from expression profiles of pattern recognition receptor (PRR) genes and identification of the most effective existing drugs using the prognostic gene signature.

METHODS

This study was based on the expression profile of PRR genes of 541 patients with UCEC obtained from The Cancer Genome Atlas. Key prognostic signatures were identified using various approaches, including survival analysis, network, and clustering. Hub genes were identified by constructing a co-expression network. Representative genes were identified using k-means and k-medoids-based clustering. Univariate Cox proportional hazard (PH) analysis was used to identify survival-associated genes. 'cmap2' was used to identify potential drugs that can suppress/enhance the expression of prognostic genes.

RESULTS

Models were developed using hub genes and achieved a maximum hazard ratio (HR) of 1.37 (p = 0.294). Then, a clustering-based model was developed using seven genes (HR 9.14; p = 1.49 × 10^-12). Finally, a nine gene-based risk stratification model was developed (CLEC1B, CLEC3A, IRF7, CTSB, FCN1, RIPK2, NLRP10, NLRP9, and SARM1) and achieved HR 10.70; p = 1.1 × 10^-12. The performance of this model improved significantly in combination with the clinical stage and achieved HR 15.23; p = 2.21 × 10^-7. We also developed a model for predicting high-risk patients (survival ≤ 4.3 years) and achieved an area under the receiver operating characteristic curve (AUROC) of 0.86.

CONCLUSION

We identified potential immunotherapeutic agents based on prognostic gene signature: hexamethonium bromide and isoflupredone. Several novel candidate drugs were suggested, including human interferon-α-2b, paclitaxel, imiquimod, MESO-DAP1, and mifamurtide. These biomolecules and repurposed drugs may be utilised for prognosis and treatment for better survival.

Anti-HER2/Neu passive-aggressive immunotherapy

Preclinical studies have established that CD8⁺ T cells are necessary for efficient immunotherapeutic regimens targeting v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2 (ERBB2, best known as HER2/Neu). Recently, we extended upon these findings by demonstrating that anti-HER2/Neu therapy also requires CD4⁺ T cells and CD40/CD40L signaling within the tumor microenvironment. Our results add to mounting evidence demonstrating that adaptive immunity is crucial to the efficacy of conventional and targeted anticancer chemotherapeutics.

Cancer Vaccines, Treatment of the Future: With Emphasis on HER2-Positive Breast Cancer

Breast cancer is one of the leading causes of death in women. With improvements in early-stage diagnosis and targeted therapies, there has been an improvement in the overall survival rate in breast cancer over the past decade. Despite the development of targeted therapies, tyrosine kinase inhibitors, as well as monoclonal antibodies and their toxin conjugates, all metastatic tumors develop resistance, and nearly one-third of HER2+ breast cancer patients develop resistance to all these therapies. Although antibody therapy has shown promising results in breast cancer patients, passive immunotherapy approaches have limitations and need continuous administration over a long period. Vaccine therapy introduces antigens that act on cancer cells causing prolonged activation of the immune system. In particular, cancer relapse could be avoided due to the presence of a longer period of immunological memory with an effective vaccine that can protect against various tumor antigens. Cancer vaccines are broadly classified as preventive and therapeutic. Preventive vaccines are used to ward off any future infections and therapeutic vaccines are used to treat a person with active disease. In this article, we provided details about the tumor environment, different types of vaccines, their advantages and disadvantages, and the current status of various vaccine candidates with a focus on vaccines for breast cancer. Current data indicate that therapeutic vaccines themselves have limitations in terms of efficacy and are used in combination with other chemotherapeutic or targeting agents. The majority of breast cancer vaccines are undergoing clinical trials and the next decade will see the fruitfulness of breast cancer vaccine therapy.

Preparation of nanoliposomes containing HER2/neu (P5+435) peptide and evaluation of their immune responses and anti-tumoral effects as a prophylactic vaccine against breast cancer

HER2/neu is an immunogenic protein inducing both humoral and cell-mediated immune responses. The antigen-specific cytotoxic T lymphocytes (CTLs) are the main effector immune cells in the anti-tumor immunity. To induce an effective CTL specific response against P5+435 single peptide derived from rat HER2/neu oncogene, we used a liposome delivery vehicle. In vivo enhancement of liposome stability and intracytoplasmic delivery of peptides are the main strategies which elevate the liposome-mediated drug delivery. Liposomes containing high transition temperature phospholipids, such as DSPC, are stable with prolonged in vivo circulation and more accessibility to the immune system. Incorporation of DOPE phospholipid results in the effective delivery of peptide into the cytoplasm via the endocytotic pathway. To this end, the P5+435 peptide was linked to Maleimide-PEG2000-DSPE and coupled on the surface of nanoliposomes containing DSPC: DSPG: Cholesterol with/without DOPE. We observed that mice vaccinated with Lip-DOPE-P5+435 formulation had the highest number of IFN-γ- producing CTLs with the highest cytotoxic activity that consequently led to significantly smallest tumor size and prolonged survival rate in the TUBO mice model. In conclusion, our study indicated that the liposomal form of P5+435 peptide containing DOPE can be regarded as a promising prophylactic anti-cancer vaccine to generate potent antigen-specific immunity.

Towards Breast Cancer Vaccines, Progress and Challenges

Breast cancer is the second leading cause of cancer death among women. National cancer institute of the US estimates that one in eight women will be diagnosed with breast cancer during their lifetime. Considering the devastating effects of the disease and the alarming numbers many scientists and research groups have devoted their research to fight breast cancer. Several recommendations are to be considered as preventing measures which include living a healthy lifestyle, regular physical activity, weight control and smoking cessation. Early detection of the disease by annual and regular mammography after the age of 40 is recommended by many healthcare institutions. This would help the diagnosis of the disease at an earlier stage and the start of the treatment before it is spread to other parts of the body. Current therapy for breast cancer includes surgical ablation, radiotherapy and chemotherapy which is often associated with adverse effects and even may lead to a relapse of the disease at a later stage. In order to achieve a long-lasting anticancer response with minimal adverse effects, development of breast cancer vaccines is under investigation by many laboratories. The immune system can be stimulated by a vaccine against breast cancer. This approach has attracted a great enthusiasm in recent years. No breast cancer vaccines have been approved for clinical use today. One breast cancer vaccine (NeuVax) has now completed clinical trial phase III and a few preventive and therapeutic breast cancer vaccines are at different steps of development. We think that with the recent advancements in immunotherapy, a breast cancer vaccine is not far from reach.

Targeted lapatinib anti-HER2/ErbB2 therapy resistance in breast cancer: opportunities to overcome a difficult problem

Approximately 20% of invasive breast cancers have upregulation/gene amplification of the oncogene human epidermal growth factor receptor-2 (HER2/ErbB2). Of these, some also express steroid receptors (the so-called Luminal B subtype), whereas others do not (the HER2 subtype). HER2 abnormal breast cancers are associated with a worse prognosis, chemotherapy resistance, and sensitivity to selected anti-HER2 targeted therapeutics. Transcriptional data from over 3000 invasive breast cancers suggest that this approach is overly simplistic; rather, the upregulation of HER2 expression resulting from gene amplification is a driver event that causes major transcriptional changes involving numerous genes and pathways in breast cancer cells. Most notably, this includes a shift from estrogenic dependence to regulatory controls driven by other nuclear receptors, particularly the androgen receptor. We discuss members of the HER receptor tyrosine kinase family, heterodimer formation, and downstream signaling, with a focus on HER2 associated pathology in breast carcinogenesis. The development and application of anti-HER2 drugs, including selected clinical trials, are discussed. In light of the many excellent reviews in the clinical literature, our emphasis is on recently developed and successful strategies to overcome targeted therapy resistance. These include combining anti-HER2 agents with programmed cell death-1 ligand or cyclin-dependent kinase 4/6 inhibitors, targeting crosstalk between HER2 and other nuclear receptors, lipid/cholesterol synthesis to inhibit receptor tyrosine kinase activation, and metformin, a broadly inhibitory drug. We seek to facilitate a better understanding of new approaches to overcome anti-HER2 drug resistance and encourage exploration of two other therapeutic interventions that may be clinically useful for HER+ invasive breast cancer patients.

Immunotherapy in HER2-positive breast cancer: state of the art and future perspectives

Breast cancer (BC) is a complex disease with primary or acquired incurability characteristics in a significant part of patients. Immunotherapeutical agents represent an emerging option for breast cancer treatment, including the human epidermal growth factor 2 positive (HER2+) subtype. The immune system holds the ability to spontaneously implement a defensive response against HER2+ BC cells through complex mechanisms which can be exploited to modulate this response for obtaining a clinical benefit. Initial immune system modulating strategies consisted mostly in vaccine therapies, which are still being investigated and improved. However, the entrance of trastuzumab into the scenery of HER2+ BC treatment was the real game changing event, which embodied a dominant immune-mediated mechanism. More recently, the advent of the immune checkpoint inhibitors has caused a new paradigm shift for immuno-oncology, with promising initial results also for HER2+ BC. Breast cancer has been traditionally considered poorly immunogenic, being characterized by relatively low tumor mutation burden (TMB). Nevertheless, recent evidence has revealed high tumor infiltrating lymphocytes (TILs) and programmed cell death-ligand 1 (PD-L1) expression in a considerable proportion of HER2+ BC patients. This may translate into a higher potential to elicit anti-cancer response and, therefore, wider possibilities for the use and implementation of immunotherapy in this subset of BC patients. We are herein presenting and critically discussing the most representative evidence concerning immunotherapy in HER2+ BC cancer, both singularly and in combination with therapeutic agents acting throughout HER2-block, immune checkpoint inhibition and anti-cancer vaccines. The reader will be also provided with hints concerning potential future projection of the most promising immutherapeutic agents and approaches for the disease of interest.

Circulating Plasmacytoid and Myeloid Dendritic Cells in Breast Cancer Patients: A Pilot Study

Purpose

Dendritic cells (DC) are a class of bone marrow-derived cells found in the blood, epithelia, and lymphoid tissues, and are the most efficient antigen presenting cells. The number and function of DC can change dramatically in cancer patients. The aim of this study is to correlate the levels of circulating DC subsets with clinical characteristics in breast cancer patients.

Methods

Peripheral blood samples were collected from 53 untreated breast cancer patients before surgery between January 2013 and November 2013. Forty-one healthy, age-matched volunteers served as the control group. The phenotypes of circulating plasmacytoid DCs (pDCs) and myeloid DCs (mDCs) were determined using fluorescence activated cell sorting assays. Correlations between DCs immunophenotypes and clinicopathologic characteristics of these breast cancer patients were then determined.

Results

Patients with breast cancer had higher levels of pDCs (p = 0.046). No relationships were observed with tumor stage and intrinsic subtype. Estrogen receptor (ER) positive patients had higher levels of mDCs than ER negative patients (p = 0.025) and human epidermal growth factor receptor 2 (HER-2) positive patients had higher levels of pDCs than HER-2 (p = 0.040). No relationships were observed with T stage, N stage, Ki67 index, histologic grade, nuclear grade, and lymphovascular invasion. In multiple regression analysis, patients with HER-2 positive breast cancer had higher levels of pDCs than HER-2 negative patients (p = 0.026).

Conclusion

An increase of pDCs in the peripheral blood of breast cancer patients was observed and patients with HER-2 positive breast cancer had higher levels of circulating pDCs than did HER-2 negative patients. Our results suggest that expression of DCs can differ according to breast cancer subtype and indicate that, with further investigation, DC expression has the possibility of being presented as a prognostic factor.

Bayesian sample size determination for phase IIA clinical trials using historical data and semi-parametric prior's elicitation

The Simon's two-stage design is the most commonly applied among multi-stage designs in phase IIA clinical trials. It combines the sample sizes at the two stages in order to minimize either the expected or the maximum sample size. When the uncertainty about pre-trial beliefs on the expected or desired response rate is high, a Bayesian alternative should be considered since it allows to deal with the entire distribution of the parameter of interest in a more natural way. In this setting, a crucial issue is how to construct a distribution from the available summaries to use as a clinical prior in a Bayesian design. In this work, we explore the Bayesian counterparts of the Simon's two-stage design based on the predictive version of the single threshold design. This design requires specifying two prior distributions: the analysis prior, which is used to compute the posterior probabilities, and the design prior, which is employed to obtain the prior predictive distribution. While the usual approach is to build beta priors for carrying out a conjugate analysis, we derived both the analysis and the design distributions through linear combinations of B-splines. The motivating example is the planning of the phase IIA two-stage trial on anti-HER2 DNA vaccine in breast cancer, where initial beliefs formed from elicited experts' opinions and historical data showed a high level of uncertainty. In a sample size determination problem, the impact of different priors is evaluated.

HER1-based vaccine: Simultaneous activation of humoral and cellular immune response

The human epidermal growth factor receptor 1 (HER1) is a tumor-associated antigen that has been validated as a clinical target for several passive, non-immune therapies currently approved for the treatment of epithelial tumors. HER1 is an oncogene that not only promotes tumor progression and survival, but also immune escape. Its overexpression in some epithelial malignancies has been correlated with a poor prognosis. We developed an approach to target HER1 by specific active immunotherapy, recognizing the extracellular domain of the receptor, using a combination of VSSP and Montanide ISA 51 as adjuvants. We summarize the results obtained with this vaccine in both the preclinical and clinical settings, emphasizing the importance of the induction of both humoral and cellular responses for the success of cancer vaccines as safe therapeutic alternatives for the treatment of cancer.

The viral approach to breast cancer immunotherapy

Despite years of intensive research, breast cancer remains the leading cause of death in women worldwide. New technologies including oncolytic virus therapies, virus, and phage display are among the most powerful and advanced methods that have emerged in recent years with potential applications in cancer prevention and treatment. Oncolytic virus therapy is an interesting strategy for cancer treatment. Presently, a number of viruses from different virus families are under laboratory and clinical investigation as oncolytic therapeutics. Oncolytic viruses (OVs) have been shown to be able to induce and initiate a systemic antitumor immune response. The possibility of application of a multimodal therapy using a combination of the OV therapy with immune checkpoint inhibitors and cancer antigen vaccination holds a great promise in the future of cancer immunotherapy. Display of immunologic peptides on bacterial viruses (bacteriophages) is also increasingly being considered as a new and strong cancer vaccine delivery strategy. In phage display immunotherapy, a peptide or protein antigen is presented by genetic fusions to the phage coat proteins, and the phage construct formulation acts as a protective or preventive vaccine against cancer. In our laboratory, we have recently tested a few peptides (E75, AE37, and GP2) derived from HER2/neu proto-oncogene as vaccine delivery modalities for the treatment of TUBO breast cancer xenograft tumors of BALB/c mice. Here, in this paper, we discuss the latest advancements in the applications of OVs and bacterial viruses display systems as new and advanced modalities in cancer immune therapeutics.

HER2-Based Immunotherapy for Breast Cancer

Resistance to therapies and disease recurrences after surgery or treatment are common challenges in breast cancer management in clinic. Active immunotherapy using human epidermal growth factor receptor 2 (HER2)-targeted vaccines represents an attractive option in combating breast cancer. Different HER2-derived vaccines have been developed over the years. Many clinical trials have been carried out in evaluating HER2-based vaccines. The authors reviewed current literature on HER2-based vaccines in clinical trials. The trials covered in this mini-review represent some of the major trials published in the past 20 years regarding the clinical use and test of HER2 vaccines. Their focus is on trials using HER2 peptide vaccines as the majority of clinical trials initiated or published used HER2 peptide-based vaccines. Findings from combination therapy trials of HER2 peptide vaccines with other treatment modalities are also presented.

Mechanisms of immune evasion in breast cancer

Tumors develop multiple mechanisms of immune evasion as they progress, with some cancer types being inherently better at ‘hiding’ than others. With an increased understanding of tumor immune surveillance, immunotherapy has emerged as a promising treatment strategy for breast cancer, despite historically being thought of as an immunologically silent neoplasm. Some types of cancer, such as melanoma, bladder, and renal cell carcinoma, have demonstrated a durable response to immunotherapeutic intervention, however, breast neoplasms have not shown the same efficacy. The causes of breast cancer’s immune silence derive from mechanisms that diminish immune recognition and others that promote strong immunosuppression. It is the mechanisms of immune evasion in breast cancers that are poorly defined. Thus, further characterization is critical for the development of better therapies. This brief review will seek to provide insight into the possible causes of weak immunogenicity and immune suppression mediated by breast cancers and highlight current immunotherapies being used to restore immune responses to breast cancer.

Developing anti-HER2 vaccines: Breast cancer experience

Breast cancer accounts for more than one million new cases annually and is the leading cause of death in women globally. HER2 overexpression induces cellular and humoral immune responses against the HER2 protein and is associated with higher tumor proliferation rates. Trastuzumab-based therapies are effectively and widely used as standard of care in HER2-amplified/overexpressed breast cancer patients; one cited mechanism of action is the induction of passive immunity and antibody-dependent cellular cytotoxicity against malignant breast cancer cells. These findings drove the efforts to generate antigen-specific immunotherapy to trigger the patient's immune system to target HER2-overexpressing tumor cells, which led to the development of various vaccines against the HER2 antigen. This article discusses the various anti-HER2 vaccine formulations and strategies and their potential role in the metastatic and adjuvant settings.

-Catenin peptide vaccines repress hepatocellular carcinoma growth via CD8+ T cell activation

As classical therapy method of advanced hepatocellular carcinoma (HCC) is not effective enough, HCC immunotherapy is a hot spot for research in recent years. Although in recent years, immune checkpoint inhibitors are focused in cancer therapy, vaccines and adoptive cell therapy (ACT), as traditional immunotherapy methods for HCC are still promising. We found that δ-Catenin might be a new tumor-associated antigen for HCC, for it could be upregulated as a stress associated protein under hypoxia and irradiation treatment. δ-Catenin peptide vaccines could inhibit the growth of subcutaneous hepatocellular tumors in vivo. According to our work, δ-Catenin peptide vaccines could stimulate the activation of cytotoxic T lymphocytes (CTLs) and enhance the infiltration of CD8+ T cells into tumors. Moreover, δ-Catenin peptide vaccines could enhance the secretion of IFN-γ and the killing of tumor cells by T cells. Mechanistically, δ-Catenin peptide vaccines, presented by antigen-presenting cells to T cells, could enhance the activation of T cells via MAPK/ERK signaling and the transcriptional factors Eomes and T-bet. Our research results indicate new potential peptide vaccines, which can be applied in clinical HCC therapy.

Chemotherapeutic agents for the treatment of metastatic breast cancer: An update

Breast cancer is the second greatest cause of death among women worldwide; it comprises a group of heterogeneous diseases that evolves due to uncontrolled cellular growth and differentiation and the loss of normal programmed cell death. There are different molecular sub-types of breast cancer; therefore, various options are selected for treatment of different forms of metastatic breast cancer. However, the use of chemotherapeutic drugs is usually accompanied by deleterious side effects and the development of drug resistance when applied for a longer period. This review offers a classification of these chemotherapeutic agents according to their modes of action and therefore improves the understanding of molecular targets that are affected during treatment. Overall, it will allow the clinician to identify more specific targets to increase the effectiveness of a drug and to reduce general toxicity, resistance and other side effects.

Immunization with HER2 extracellular subdomain proteins induces cellular response and tumor growth inhibition in mice

AIM

We investigated cellular and protective immune responses in mice vaccinated with recombinant HER2 extracellular subdomains.

MATERIALS & METHODS

Balb/C mice were immunized with recombinant full HER2 extracellular domain and subdomain proteins. Humoral and cellular immune response and antitumor effect was evaluated using a syngeneic mice tumor model.

RESULTS

All recombinant proteins induced secretion of IL-4 and particularly IFN-γ and IL-17 cytokines. Challenging of immunized mice with stable 4T1-HER2 transfected cells resulted in partial but significant tumor growth inhibition in all groups of mice particularly those immunized with fHER2-ECD together with CPG.

CONCLUSION

Our results suggest that the recombinant HER2-ECD subdomains induce mainly Th1 and Th17 responses, which seem to contribute to tumor growth inhibition in syngeneic mice.

Present status and future perspective of peptide-based vaccine therapy for urological cancer

Use of peptide‐based vaccines as therapeutics aims to elicit immune responses through antigenic epitopes derived from tumor antigens. Peptide‐based vaccines are easily synthesized and lack significant side‐effects when given in vivo. Peptide‐based vaccine therapy against several cancers including urological cancers has made progress for several decades, but there is no worldwide approved peptide vaccine. Peptide vaccines were also shown to induce a high frequency of immune response in patients accompanied by clinical efficacy. These data are discussed in light of the recent progression of immunotherapy caused by the addition of immune checkpoint inhibitors thus providing a general picture of the potential therapeutic efficacy of peptide‐based vaccines and their combination with other biological agents. In this review, we discuss the mechanism of the antitumor effect of peptide‐based vaccine therapy, development of our peptide vaccine, recent clinical trials using peptide vaccines for urological cancers, and perspectives of peptide‐based vaccine therapy.

Cancer testis antigen Sperm Protein 17 as a new target for triple negative breast cancer immunotherapy

Breast carcinoma is a major health issue for millions of women. Current therapies have serious side effects, and are only partially effective in patients with metastatic tumors. Thus, the need for novel and less toxic therapies is urgent. Moreover, hormonal and antibody therapies effective in other subtypes are not effective in Triple Negative Breast Cancer (TNBC). Immunotherapeutic strategies directed against specific tumor-associated antigens (TAAs) and mediated by specific cytotoxic T lymphocytes (CTL) have been largely underexplored in this disease. Cancer-testis antigens (CTA) are a group of TAAs displaying the ideal characteristics of promising vaccine targets, i.e. strong immunogenicity and cancer specificity. The CTA, Sperm Protein 17 (SP17), has been found to be aberrantly expressed in different neoplasms, including ovarian and esophageal cancers, nervous system tumors and multiple myeloma, and has been suggested as a candidate target for immunotherapy.

Here, we evaluated SP17 expression levels in breast cancer cell lines, invasive ductal breast carcinoma, including patients with TNBC, and adjacent non-neoplastic breast tissue, and determined whether SP17 was capable of generating SP17-specific cytotoxic T lymphocytes in vitro.

We showed that SP17 is expressed in breast cancer cell lines and primary breast tumors and importantly in TNBC subtype, but not in adjacent non-tumoral breast tissue or unaffected tissues, except in male germinal cells. Furthermore, we detected specific anti-SP17 antibodies in patients’ sera and we generated SP17-specific, HLA class I-restricted, cytotoxic T lymphocytes capable of efficiently killing breast cancer cells.

Treating breast cancer with cell-based approaches: an overview

INTRODUCTION

Breast cancer is the most common malignancy in women. Despite there being considerable progress in the treatment of this disease, metastatic dissemination is still considered an incurable condition at the present time, causing 500,000 deaths worldwide every year. Although most of the research efforts have been focused on pharmacological approaches, over the last three decades, the use of bone marrow and peripheral blood-derived cell therapy approaches have been attempted and developed. Areas covered: This review will briefly address cell therapy for breast cancer, including autologous stem cell transplantations for overcoming the myelosuppressive effects of high-dose chemotherapy, allogeneic stem cell transplants and adoptive immunotherapy using bone-marrow derived T-cells. Expert opinion: The treatment of breast cancer using bone marrow or peripheral-blood derived cells has evolved from a supportive care approach to allow dose escalation of conventional chemotherapy to a therapeutic strategy aimed at eliciting immune cell mediated anticancer immunity. This latter principle has led to the development of adoptive immunotherapies, either with 'natural' or genetically engineered effectors, which are being intensively investigated for their great potential against several solid tumors, including breast cancer.

Specific immunotherapy in ovarian cancer: a systematic review

Epithelial ovarian cancer (EOC) is the most lethal gynecological cancer. Several approaches of active and passive immunotherapy for EOC have been studied. The aim of this systematic review was to assess the clinical efficacy of specific immunotherapy in patients with EOC. We found 4524 references in seven databases and we included ten controlled clinical trials with 2285 patients with EOC reporting five active immunotherapeutic agents and three passive immunotherapies. Meta-analysis of six studies showed that overall there was not any significant difference in overall survival and recurrence-free survival between patients undergoing specific immunotherapy and those in control group. Most of the studies we evaluated reported a positive outcome from treatment with specific immunotherapy, although this was not significant.

Receptor tyrosine kinase-like orphan receptor 1 (ROR-1): An emerging target for diagnosis and therapy of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is characterized by reposition of malignant B cells in the blood, bone marrow, spleen and lymph nodes. It remains the most common leukemia in the Western world. Within the recent years, major breakthroughs have been made to prolong the survival and improve the health of patients. Despite these advances, CLL is still recognized as a disease without definitive cure. New treatment approaches, based on unique targets and novel drugs, are highly desired for CLL therapy. The Identification and subsequent targeting of molecules that are overexpressed uniquely in malignant cells not normal ones play critical roles in the success of anticancer therapeutic strategies. In this regard, ROR family proteins are known as a subgroup of protein kinases which have gained huge popularity in the scientific community for the diagnosis and treatment of different cancer types. ROR1 as an antigen exclusively expressed on the surface of tumor cells can be a target for immunotherapy. ROR-1 targeting using different approaches such as siRNA, tyrosine kinase inhibitors, cell therapy and antibody induces tumor growth suppression in cancer cells. In the current review, we aim to present an overview of the efforts and scientific achievements in targeting ROR family, particularly ROR-1, for the diagnosis and treatment of chronic lymphocytic leukemia (CLL).

Prognostic value of tumor infiltrating lymphocyte subsets in breast cancer depends on hormone receptor status

PURPOSE

Interaction between immune-regulatory proteins and tumor infiltrating lymphocytes (TILs) is complex, and their associations may have significant clinical implications. This study was designed to evaluate the relationships between immunomodulatory proteins and TIL subsets and their impact on prognosis in breast cancer.

METHODS

377 invasive breast cancer cases were selected, and immunohistochemistry was performed for HLA-A, HLA-ABC, and indoleamine 2,3-dioxygenase (IDO); CD4+, CD8+, and FOXP3+ T cells were counted in intratumoral and stromal areas for both absolute numbers as well as their ratios.

RESULTS

While HLA-ABC and HLA-A expressions showed a positive correlation with CD8+ and FOXP3+ TIL infiltration, IDO expression showed a negative correlation with FOXP3+/CD4+ and FOXP3+/CD8+ T cell ratios. Expressions of HLA-ABC, HLA-A, and IDO shared an association with negative estrogen receptor status. Infiltration of CD4+, CD8+, and FOXP3+ TILs was significantly higher in tumors with high histologic grade, negative hormone receptor status, HER2 amplification, high Ki-67 index, and p53 overexpression. In survival analyses, increased CD4+ TIL infiltration was associated with better prognosis of the patients while other TIL subset infiltration and expression of immunomodulatory proteins had no prognostic significance. In subgroup analyses, high CD4+ TIL infiltration was revealed as an independent good prognostic factor in hormone receptor-negative subgroup while high FOXP3+/CD8+ T cell ratio was found to be an independent adverse prognostic factor in hormone receptor-positive subgroup, especially in luminal A subtype.

CONCLUSION

CD4+ TIL subset and FOXP3+/CD8+ T cell ratio have different prognostic significance in breast cancer according to hormone receptor status.

Receptor tyrosine kinases in carcinogenesis

Receptor tyrosine kinases (RTKs) are cell surface glycoproteins with enzymatic activity involved in the regulation of various important functions. In all-important physiological functions including differentiation, cell-cell interactions, survival, proliferation, metabolism, migration and signaling these receptors are the key players of regulation. Additionally, mutations of RTKs or their overexpression have been described in many human cancers and are being explored as a novel avenue for a new therapeutic approach. Some of the deregulated RTKs observed to be significantly affected in cancers included vascular endothelial growth factor receptor, epidermal growth factor receptor, fibroblast growth factor receptor, RTK-like orphan receptor 1 (ROR1) and the platelet-derived growth factor receptor. These deregulated RTKs offer attractive possibilities for the new anticancer therapeutic approach involving specific targeting by monoclonal antibodies as well as kinase. The present review aimed to highlight recent perspectives of RTK ROR1 in cancer.

Why man's best friend, the dog, could also benefit from an anti-HER-2 vaccine

Human epidermal growth factor receptor-2 (HER-2) is a well-established target for anticancer anticancerprecision medicine in humans. A HER-2 homologue with 92% amino acid identity has been described in canine mammary tumors, which whichis termed here as ‘dog epidermal growth factor receptor-2 (DER-2)’, with similar biological implications as those in human breast cancer. Both antigens can principally be immunologically targeted by anti-HER-2 antibodies, such as trastuzumab; however, the in vivo application applicationof humanized antibodies to other species would lead to specific hypersensitivity reactions. Therefore, HER-2 mimotope vaccines that actively induce autologous trastuzumab-like immunoglobulins represent a novel and economic treatment option to overcome species-specific limitations. Thus, the present review proposes the implementation of clinical trials with HER-2 vaccines in canine cancer model modelpatients with spontaneous DER-2 positive mammary gland carcinomas in order to assess their safety and efficacy. This approach would not only pave the way into the veterinary oncology market, but would also similarly generate robust data for human trials and facilitate the testing of novel combinatorial treatments.

Immunotherapy of cancer: from monoclonal to oligoclonal cocktails of anti-cancer antibodies: IUPHAR Review 18

Antibody-based therapy of cancer employs monoclonal antibodies (mAbs) specific to soluble ligands, membrane antigens of T-lymphocytes or proteins located at the surface of cancer cells. The latter mAbs are often combined with cytotoxic regimens, because they block survival of residual fractions of tumours that evade therapy-induced cell death. Antibodies, along with kinase inhibitors, have become in the last decade the mainstay of oncological pharmacology. However, partial and transient responses, as well as emergence of tumour resistance, currently limit clinical application of mAbs. To overcome these hurdles, oligoclonal antibody mixtures are being tested in animal models and in clinical trials. The first homo-combination of two mAbs, each engaging a distinct site of HER2, an oncogenic receptor tyrosine kinase (RTK), has been approved for treatment of breast cancer. Likewise, a hetero-combination of antibodies to two distinct T-cell antigens, PD1 and CTLA4, has been approved for treatment of melanoma. In a similar vein, additive or synergistic anti-tumour effects observed in animal models have prompted clinical testing of hetero-combinations of antibodies simultaneously engaging distinct RTKs. We discuss the promise of antibody cocktails reminiscent of currently used mixtures of chemotherapeutics and highlight mechanisms potentially underlying their enhanced clinical efficacy.

Design of Polyepitope DNA Vaccine against Breast Carcinoma Cells and Analysis of Its Expression in Dendritic Cells

Polyepitope DNA vaccine inducing T-cell-mediated immune response against cancer-specific antigens is a promising tool for selective elimination of tumor cells. Breast cancer-specific polyepitope DNA vaccine was designed using TEpredict and PolyCTLDesigner software on the basis of immunogenic peptides of HER2 and Mammaglobin-1 (Mam) tumor antigens. LPS-free preparations of plasmid DNA encoding polyepitope T-cell antigen and full-length copies of HER2 and Mam antigens were obtained. TaqMan-PCR systems for evaluation of the expression of immunogens in cells were created. The protocol of vaccine DNA delivery into dendritic cells was optimized. Expression of the target immunogens in dendritic cells derived from human peripheral blood mononuclear fraction after transfection with plasmid DNA preparations is demonstrated.

Design and characterization of the tumor vaccine MGN1601, allogeneic fourfold gene-modified vaccine cells combined with a TLR-9 agonist

The tumor vaccine MGN1601 was designed and developed for treatment of metastatic renal cell carcinoma (mRCC). MGN1601 consists of a combination of fourfold gene-modified cells with the toll-like receptor 9 agonist dSLIM, a powerful connector of innate and adaptive immunity. Vaccine cells originate from a renal cell carcinoma cell line (grown from renal cell carcinoma tissue), express a variety of known tumor-associated antigens (TAA), and are gene modified to transiently express two co-stimulatory molecules, CD80 and CD154, and two cytokines, GM-CSF and IL-7, aimed to support immune response. Proof of concept of the designed vaccine was shown in mice: The murine homologue of the vaccine efficiently (100%) prevented tumor growth when used as prophylactic vaccine in a syngeneic setting. Use of the vaccine in a therapeutic setting showed complete response in 92% of mice as well as synergistic action and necessity of the components. In addition, specific cellular and humoral immune responses in mice were found when used in an allogeneic setting. Immune response to the vaccine was also shown in mRCC patients treated with MGN1601: Peptide array analysis revealed humoral CD4-based immune response to TAA expressed on vaccine cells, including survivin, cyclin D1, and stromelysin.

Emerging Therapeutic Options for HER2-Positive Breast Cancer

The natural history of HER2-positive breast cancer has progressively improved since the introduction of the first anti-HER2 directed therapy (trastuzumab). Trastuzumab has significantly increased survival of patients with HER2-positive metastatic breast cancer and, after the standardization of the use of this drug in the adjuvant setting in 2005, has also avoided many disease recurrences and, consequently, saved many lives. Later on, the introduction of lapatinib offered new choices for patients with advanced HER2-positive breast cancer, although the drug has failed to show a clear efficacy in the adjuvant setting. New promising drugs have been approved to broaden the horizon of HER2-positive breast cancer such as pertuzumab or T-DM1, but we need new options to further improve the management of these diseases. In this review, we cover new strategies that are currently under evaluation for the treatment of patients with HER2-positive breast cancer, including new tyrosine kinase inhibitors (neratinib, ONT-380), new antibody-drug conjugates targeting HER2 (MM-302), and new indications of already approved drugs (T-DM1), as well as the potential dual combinations of anti-HER2 therapy with phosphoinositide 3-kinase/mTOR or cell cycle inhibitors (palbociclib, abemaciclib). Last but not least, we briefly review a new paradigm of emerging approaches that involve the host immune response, HER2 breast cancer vaccines, and other immune strategies, including immune checkpoint inhibition.

Meeting report VLPNPV: Session 5: Plant based technology

The VLPNPV 2014 Conference that was convened at the Salk institute was the second conference of its kind to focus on advances in production, purification, and delivery of virus-like particles (VLPs) and nanoparticles. Many exciting developments were reported and discussed in this interdisciplinary arena, but here we report specifically on the contributions of plant-based platforms to VLP vaccine technology as reported in the section of the conference devoted to the topic as well in additional presentations throughout the meeting. The increasing popularity of plant production platforms is due to their lower cost, scalability, and lack of contaminating animal pathogens seen with other systems. Reports include production of complex VLPs consisting of 4 proteins expressed at finely-tuned expression levels, a prime-boost strategy for HIV vaccination using plant-made VLPs and a live viral vector, and the characterization and development of plant viral nanoparticles for use in cancer vaccines, drug delivery, and bioimaging.

Antibody response to HER2 extracellular domain and subdomains in mouse following DNA immunization

Human epidermal growth factor receptor 2 (HER2) is overexpressed in 15-20 % of breast cancer patients and is an appropriate target for immunotherapy in these patients. Monoclonal antibodies (mAbs) specific to HER2 are currently applied to treat breast cancer patients with HER2 overexpression. Active immunization with HER2 DNA or protein has been considered as a suitable alternative. The aim of this study is to evaluate anti-HER2 antibody response in serum of mice immunized with DNA constructs containing full extracellular domain (fECD) or subdomains of human HER2. Four extracellular subdomains and also fECD of HER2 were cloned into pCMV6-Neo vector. Different groups of Balb/C mice were immunized with HER2 DNA constructs and boosted with HER2 recombinant protein. The anti-HER2 antibody was subsequently determined by ELISA, flow cytometry, and immunohistochemistry. Anti-HER2 antibody was detected only in serum of mice immunized with fECD DNA. None of HER2 extracellular subdomains induced appreciable levels of anti-HER2 antibody. However, boosting with fECD or extracellular subdomain III (DIII) recombinant protein resulted in enhanced anti-HER2 fECD as well as anti-HER2 subdomain antibody responses. In this regard, almost all (99 %) of HER2-overexpressing BT474 cells could be detected by serum antibody from mice immunized with HER2 subdomain DNA and boosted with recombinant HER2 protein by flow cytometry. Similarly, serum of mice immunized with DIII DNA construct and boosted with recombinant DIII protein could also recognize these cells, but to a lesser extent (50 %). Our findings suggest that combination of HER2 DNA and protein immunization could effectively induce anti-HER2 antibody response in Balb/C mice.

Combining immunotherapy and anticancer agents: the right path to achieve cancer cure?

Recent clinical trials revealed the impressive efficacy of immunological checkpoint blockade in different types of metastatic cancers. Such data underscore that immunotherapy is one of the most promising strategies for cancer treatment. In addition, preclinical studies provide evidence that some cytotoxic drugs have the ability to stimulate the immune system, resulting in anti-tumor immune responses that contribute to clinical efficacy of these agents. These observations raise the hypothesis that the next step for cancer treatment is the combination of cytotoxic agents and immunotherapies. The present review aims to summarize the immune-mediated effects of chemotherapeutic agents and their clinical relevance, the biological and clinical features of immune checkpoint blockers and finally, the preclinical and clinical rationale for novel therapeutic strategies combining anticancer agents and immune checkpoint blockers.

A retrospective analysis of the activity and safety of oral Etoposide in heavily pretreated metastatic breast cancer patients

Metastatic breast cancer (MBC) patients derive benefit from chemotherapy, but options become limited after several prior chemotherapeutic regimens. Oral etoposide (VP-16) has previously been found to be clinically active in MBC patients in phase II trials. However, with increasing availability of other drugs, etoposide use has declined in spite of its unfavorable toxicity profile probably being overestimated. We therefore evaluated the clinical benefit and safety of oral etoposide in a population of MBC patients who had failed multiple regimens of currently used therapies. Sixty-six patients with MBC previously treated with a median of eight (range 2-13) regimens of therapy were eligible for the study. Patients received 50 mg/day oral etoposide in 20-day cycles with 1-week of rest. All patients were evaluated for clinical benefit (clinical benefit rate [CBR], complete response, partial response, and disease stabilization >24 weeks), progression-free survival (PFS), overall survival (OS), and toxicities. Median PFS was 4 months, CBR was 18% (overall response rate 4%), and median OS from the start of treatment was 11 months. Little clinically significant or high-grade toxicity were observed. No patients withdrew from treatment due to etoposide-induced toxicity. The favorable clinical response, low toxicity, and low cost of the drug suggest that etoposide is a viable option for patients with heavily pretreated MBC.

The adjuvant effects of high-molecule-weight polysaccharides purified from Antrodia cinnamomea on dendritic cell function and DNA vaccines

The biological activity of the edible basidiomycete Antrodia cinnamomea (AC) has been studied extensively. Many effects, such as anti-cancer, anti-inflammatory, and antioxidant activities, have been reported from either crude extracts or compounds isolated from AC. However, research addressing the function of AC in enhancing immunity is rare. The aim of the present study is to investigate the active components and the mechanism involved in the immunostimulatory effect of AC. We found that polysaccharides (PS) in the water extract of AC played a major role in dendritic cell (DC) activation, which is a critical leukocyte in initiating immune responses. We further size purified and identified that the high-molecular weight PS fraction (greater than 100 kDa) exhibited the activating effect. The AC high-molecular weight PSs (AC hmwPSs) promoted pro-inflammatory cytokine production by DCs and the maturation of DCs. In addition, DC-induced antigen-specific T cell activation and Th1 differentiation were increased by AC hmwPSs. In studying the molecular mechanism, we confirmed the activation of the MAPK and NF-κB pathways in DCs after AC hmwPSs treatment. Furthermore, we demonstrated that TLR2 and TLR4 are required for the stimulatory activity of AC hmwPSs on DCs. In a mouse tumor model, we demonstrated that AC hmwPSs enhanced the anti-tumor efficacy of the HER-2/neu DNA vaccine by facilitating specific Th1 responses. Thus, we conclude that hmwPSs are the major components of AC that stimulate DCs via the TLR2/TLR4 and NF-κB/MAPK signaling pathways. The AC hmwPSs have potential to be applied as adjuvants.