Dendritic Cell Vaccination Enhances Immune Responses and Induces Regression of HER2pos DCIS Independent of Route: Results of Randomized Selection Design Trial

Anti-Tumor Immunity to Patient-Derived Breast Cancer Cells by Vaccination with Interferon-Alpha-Conditioned Dendritic Cells (IFN-DC)

BACKGROUND

Breast cancer represents one of the leading causes of death among women. Surgery can be effective, but once breast cancer has metastasized, it becomes extremely difficult to treat. Conventional therapies are associated with substantial toxicity and poor efficacy due to tumor heterogeneity, treatment resistance and disease relapse. Moreover, immune checkpoint blockade appears to offer limited benefit in breast cancer. The poor tumor immunogenicity and the immunosuppressive tumor microenvironment result in scarce T-cell infiltration, leading to a low response rate. Thus, there is considerable interest in the development of improved active immunotherapies capable of sensitizing a patient's immune system against tumor cells.

METHODS

We evaluated the in vitro anti-tumor activity of a personalized vaccine based on dendritic cells generated in the presence of interferon (IFN)-α and granulocyte-macrophage colony-stimulating factor (IFN-DC) and loaded with an oxidized lysate from autologous tumor cells expanded as 3D organoid culture maintaining faithful tumor antigenic profiles.

RESULTS

Our findings demonstrate that stimulation of breast cancer patients' lymphocytes with autologous IFN-DC led to efficient Th1-biased response and the generation in vitro of potent cytotoxic activity toward the patients' own tumor cells.

CONCLUSIONS

This approach can be potentially applied in association with checkpoint blockade and chemotherapy in the design of new combinatorial therapies for breast cancer.

Deciphering CD4+ T cell-mediated responses against cancer

It's been long thought that CD8+ cytotoxic T cells play a major role in T cell-mediated antitumor responses, whereas CD4+ T cells merely provide some assistance to CD8+ T cells as the "helpers." In recent years, numerous studies support the notion that CD4+ T cells play an indispensable role in antitumor responses. Here, we summarize and discuss the current knowledge regarding the roles of CD4+ T cells in antitumor responses and immunotherapy, with a focus on the molecular and cellular mechanisms behind these observations. These new insights on CD4+ T cells may pave the way to further optimize cancer immunotherapy.

Update on Management of Ductal Carcinoma in Situ

Ductal carcinoma in situ (DCIS) represents 18% to 25% of all diagnosed breast cancers, and is a noninvasive, nonobligate precursor lesion to invasive cancer. The diagnosis of DCIS represents a wide range of disease, including lesions with both low and high risk of progression to invasive cancer and recurrence. Over the past decade, research on the topic of DCIS has focused on the possibility of tailoring treatment for patients according to their risk for progression and recurrence, which is based on clinicopathologic, biomolecular and genetic factors. These efforts are ongoing, with recently completed and continuing clinical trials spanning the continuum of cancer care. We conducted a review to identify recent advances on the topic of diagnosis, risk stratification and management of DCIS. While novel imaging techniques have increased the rate of DCIS diagnosis, questions persist regarding the optimal management of lesions that would not be identified with conventional methods. Additionally, among trials investigating the potential for omission of surgery and use of active surveillance, 2 trials have completed accrual and 2 clinical trials are continuing to enroll patients. Identification of novel genetic patterns is expanding our potential for risk stratification and aiding our ability to de-escalate radiation and systemic therapies for DCIS. These advances provide hope for tailoring of DCIS treatment in the near future.

Intratumoral delivery of immunotherapy to treat breast cancer: current development in clinical and preclinical studies

Breast cancer poses one of the largest threats to women's health. Treatment continues to improve for all the subtypes of breast cancer, but some subtypes, such as triple negative breast cancer, still present a significant treatment challenge. Additionally, metastasis and local recurrence are two prevalent problems in breast cancer treatment. A newer type of therapy, immunotherapy, may offer alternatives to traditional treatments for difficult-to-treat subtypes. Immunotherapy engages the host's immune system to eradicate disease, with the potential to induce long-lasting, durable responses. However, systemic immunotherapy is only approved in a limited number of indications, and it benefits only a minority of patients. Furthermore, immune related toxicities following systemic administration of potent immunomodulators limit dosing and, consequently, efficacy. To address these safety considerations and improve treatment efficacy, interest in local delivery at the site of the tumor has increased. Numerous intratumorally delivered immunotherapeutics have been and are being explored clinically and preclinically, including monoclonal antibodies, cellular therapies, viruses, nucleic acids, cytokines, innate immune agonists, and bacteria. This review summarizes the current and past intratumoral immunotherapy clinical landscape in breast cancer as well as current progress that has been made in preclinical studies, with a focus on delivery parameters and considerations.

Modulation of the tumor microenvironment and mechanism of immunotherapy-based drug resistance in breast cancer

Breast cancer, the most frequent female malignancy, is often curable when detected at an early stage. The treatment of metastatic breast cancer is more challenging and may be unresponsive to conventional therapy. Immunotherapy is crucial for treating metastatic breast cancer, but its resistance is a major limitation. The tumor microenvironment (TME) is vital in modulating the immunotherapy response. Various tumor microenvironmental components, such as cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), and myeloid-derived suppressor cells (MDSCs), are involved in TME modulation to cause immunotherapy resistance. This review highlights the role of stromal cells in modulating the breast tumor microenvironment, including the involvement of CAF-TAM interaction, alteration of tumor metabolism leading to immunotherapy failure, and other latest strategies, including high throughput genomic screening, single-cell and spatial omics techniques for identifying tumor immune genes regulating immunotherapy response. This review emphasizes the therapeutic approach to overcome breast cancer immune resistance through CAF reprogramming, modulation of TAM polarization, tumor metabolism, and genomic alterations.

Progression from ductal carcinoma in situ to invasive breast cancer: molecular features and clinical significance

Ductal carcinoma in situ (DCIS) represents pre-invasive breast carcinoma. In untreated cases, 25-60% DCIS progress to invasive ductal carcinoma (IDC). The challenge lies in distinguishing between non-progressive and progressive DCIS, often resulting in over- or under-treatment in many cases. With increasing screen-detected DCIS in these years, the nature of DCIS has aroused worldwide attention. A deeper understanding of the biological nature of DCIS and the molecular journey of the DCIS-IDC transition is crucial for more effective clinical management. Here, we reviewed the key signaling pathways in breast cancer that may contribute to DCIS initiation and progression. We also explored the molecular features of DCIS and IDC, shedding light on the progression of DCIS through both inherent changes within tumor cells and alterations in the tumor microenvironment. In addition, valuable research tools utilized in studying DCIS including preclinical models and newer advanced technologies such as single-cell sequencing, spatial transcriptomics and artificial intelligence, have been systematically summarized. Further, we thoroughly discussed the clinical advancements in DCIS and IDC, including prognostic biomarkers and clinical managements, with the aim of facilitating more personalized treatment strategies in the future. Research on DCIS has already yielded significant insights into breast carcinogenesis and will continue to pave the way for practical clinical applications.

Dendritic Cells in Cancer Immunology and Immunotherapy

Cancer immunotherapy modulates the immune system, overcomes immune escape and stimulates immune defenses against tumors. Dendritic cells (DCs) are professional promoters of immune responses against tumor antigens with the outstanding ability to coordinate the innate and adaptive immune systems. Evidence suggests that there is a decrease in both the number and function of DCs in cancer patients. Therefore, they represent a strong scaffold for therapeutic interventions. DC vaccination (DCV) is safe, and the antitumoral responses induced are well established in solid tumors. Although the addition of checkpoint inhibitors (CPIs) to chemotherapy has provided new options in the treatment of cancer, they have shown no clinical benefit in immune desert tumors or in those tumors with dysfunctional or exhausted T-cells. In this way, DC-based therapy has demonstrated the ability to modify the tumor microenvironment for immune enriched tumors and to potentiate systemic host immune responses as an active approach to treating cancer patients. Application of DCV in cancer seeks to obtain long-term antitumor responses through an improved T-cell priming by enhancing previous or generating de novo immune responses. To date, DCV has induced immune responses in the peripheral blood of patients without a significant clinical impact on outcome. Thus, improvements in vaccines formulations, selection of patients based on biomarkers and combinations with other antitumoral therapies are needed to enhance patient survival. In this work, we review the role of DCV in different solid tumors with their strengths and weaknesses, and we finally mention new trends to improve the efficacy of this immune strategy.

Reviewing the significance of dendritic cell vaccines in interrupting breast cancer development

Breast cancer is a heterogeneous disease and is the most prevalent cancer in women. According to the U.S breast cancer statistics, about 1 in every 8 women develop an invasive form of breast cancer during their lifetime. Immunotherapy has been a significant advancement in the treatment of cancer with multiple studies reporting favourable patient outcomes by modulating the immune response to cancer cells. Here, we review the significance of dendritic cell vaccines in treating breast cancer patients. We discuss the involvement of dendritic cells and oncodrivers in breast tumorigenesis, highlighting the rationale for targeting oncodrivers and neoantigens using dendritic cell vaccine therapy. We review different dendritic cell subsets and maturation states previously used to develop vaccines and suggest the use of DC vaccines for breast cancer prevention. Further, we highlight that the intratumoral delivery of type 1 dendritic cell vaccines in breast cancer patients activates tumor antigen-specific CD4+ T helper cell type 1 (Th1) cells, promoting an anti-tumorigenic immune response while concurrently blocking pro-tumorigenic responses. In summary, this review provides an overview of the current state of dendritic cell vaccines in breast cancer highlighting the challenges and considerations necessary for an efficient dendritic cell vaccine design in interrupting breast cancer development.

Deciphering tumor-infiltrating dendritic cells in the single-cell era

Dendritic cells (DCs) serve as a pivotal link connecting innate and adaptive immunity by processing tumor-derived antigens and activating T cells. The advent of single-cell sequencing has revolutionized the categorization of DCs, enabling a high-resolution characterization of the previously unrecognized diversity of DC populations infiltrating the intricate tumor microenvironment (TME). The application of single-cell sequencing technologies has effectively elucidated the heterogeneity of DCs present in the tumor milieu, yielding invaluable insights into their subpopulation structures and functional diversity. This review provides a comprehensive summary of the current state of knowledge regarding DC subtypes in the TME, drawing from single-cell studies conducted across various human tumors. We focused on the categorization, functions, and interactions of distinct DC subsets, emphasizing their crucial roles in orchestrating tumor-related immune responses. Additionally, we delve into the potential implications of these findings for the identification of predictive biomarkers and therapeutic targets. Enhanced insight into the intricate interplay between DCs and the TME promises to advance our comprehension of tumor immunity and, in turn, pave the way for the development of more efficacious cancer immunotherapies.

Recent advances in exosome-based immunotherapy applied to cancer

Cancer stands as a prominent contributor to global mortality rates, necessitating immediate attention toward the exploration of its treatment options. Extracellular vesicles have been investigated as a potential cancer therapy in recent years. Among them, exosomes, as cell-derived nanovesicles with functions such as immunogenicity and molecular transfer, offer new possibilities for immunotherapy of cancer. However, multiple studies have shown that exosomes of different cellular origins have different therapeutic effects. The immunomodulatory effects of exosomes include but are not limited to inhibiting or promoting the onset of immune responses, regulating the function of molecular signaling pathways, and serving as carriers of antitumor drugs. Therefore, this mini-review attempts to summarize and evaluate the development of strategies for using exosomes to package exogenous cargos to promote immunotherapy in cancer.

The role of CD4+ T cells in tumor and chronic viral immune responses

Immunotherapies are mainly aimed to promote a CD8+ T cell response rather than a CD4+ T cell response as cytotoxic T lymphocytes (CTLs) can directly kill target cells. Recently, CD4+ T cells have received more attention due to their diverse roles in tumors and chronic viral infections. In antitumor and antichronic viral responses, CD4+ T cells relay help signals through dendritic cells to indirectly regulate CD8+ T cell response, interact with B cells or macrophages to indirectly modulate humoral immunity or macrophage polarization, and inhibit tumor blood vessel formation. Additionally, CD4+ T cells can also exhibit direct cytotoxicity toward target cells. However, regulatory T cells exhibit immunosuppression and CD4+ T cells become exhausted, which promote tumor progression and chronic viral persistence. Finally, we also outline immunotherapies based on CD4+ T cells, including adoptive cell transfer, vaccines, and immune checkpoint blockade. Overall, this review summarizes diverse roles of CD4+ T cells in the antitumor or protumor and chronic viral responses, and also highlights the immunotherapies based on CD4+ T cells, giving a better understanding of their roles in tumors and chronic viral infections.

Breast Cancer Risk Reduction: Current Status and Emerging Trends to Increase Efficacy and Reduce Toxicity of Preventive Medication

The primary prevention of breast cancer is a worthwhile goal for which the efficacy of antiestrogens is well established. However, implementation has been problematic related to low prioritization by providers and the reluctance of high-risk women to experience medication side effects. Emerging solutions include improved risk estimation through the use of polygenic risk scores and the application of radiomics to screening mammograms; and optimization of medication dose to limit toxicity. The identification of agents to prevent estrogen receptor negative or HER2-positive tumors is being pursued, but personalization of medical risk reduction requires the prediction of tumor subtypes.

Worth a Pound of Cure? Emerging Strategies and Challenges in Cancer Immunoprevention

Cancer immunoprevention applies immunologic approaches such as vaccines to prevent, rather than to treat or cure, cancer. Despite limited success in the treatment of advanced disease, the development of cancer vaccines to intercept premalignant states is a promising area of current research. These efforts are supported by the rationale that vaccination in the premalignant setting is less susceptible to mechanisms of immune evasion compared with established cancer. Prophylactic vaccines have already been developed for a minority of cancers mediated by oncogenic viruses (e.g., hepatitis B and human papillomavirus). Extending the use of preventive vaccines to non-virally driven malignancies remains an unmet need to address the rising global burden of cancer. This review provides a broad overview of clinical trials in cancer immunoprevention with an emphasis on emerging vaccine targets and delivery platforms, translational challenges, and future directions.

Glioblastoma Multiforme: The Latest Diagnostics and Treatment Techniques

BACKGROUND

Glioblastoma multiforme (GBM) is a WHO grade 4 glioma and the most common malignant primary brain tumour. Recently, there has been outstanding progress in the treatment of GBM. In addition to the newest form of GBM removal using fluorescence, three-dimensional (3D) imaging, tomoradiotherapy, moderate electro-hyperthermia, and adjuvant temozolomide (post-operative chemotherapy), new developments have been made in the fields of immunology, molecular biology, and virotherapy. An unusual and modern treatment has been created, especially for stage 4 GBM, using the latest therapeutic techniques, including immunotherapy and virotherapy. Modern oncological medicine is producing extraordinary and progressive therapeutic methods. Oncological therapy includes individual analysis of the properties of a tumour and targeted therapy using small-molecule inhibitors. Individualised medicine covers the entire patient (tumour and host) in the context of immunotherapy. An example is individualised multimodal immunotherapy (IMI), which relies on individual immunological tumour-host interactions. In addition, IMI is based on the concept of oncolytic virus-induced immunogenic tumour cell death.

SUMMARY

In this review, we outline current knowledge of the various available treatment options used in the therapy of GBM including both traditional therapeutic strategy and modern therapies, such as tomotherapy, electro-hyperthermia, and oncolytic virotherapy, which are promising treatment strategies with the potential to improve prognosis in patients with GBM.

KEY MESSAGES

This newest therapy, immunotherapy combined with virotherapy (oncolytic viruses and cancer vaccines), is displaying encouraging signs for combating GBM. Additionally, the latest 3D imaging is compared to conventional two-dimensional imaging.

Signaling pathways involved in the biological functions of dendritic cells and their implications for disease treatment

The ability of dendritic cells (DCs) to initiate and regulate adaptive immune responses is fundamental for maintaining immune homeostasis upon exposure to self or foreign antigens. The immune regulatory function of DCs is strictly controlled by their distribution as well as by cytokines, chemokines, and transcriptional programming. These factors work in conjunction to determine whether DCs exert an immunosuppressive or immune-activating function. Therefore, understanding the molecular signals involved in DC-dependent immunoregulation is crucial in providing insight into the generation of organismal immunity and revealing potential clinical applications of DCs. Considering the many breakthroughs in DC research in recent years, in this review we focused on three basic lines of research directly related to the biological functions of DCs and summarized new immunotherapeutic strategies involving DCs. First, we reviewed recent findings on DC subsets and identified lineage-restricted transcription factors that guide the development of different DC subsets. Second, we discussed the recognition and processing of antigens by DCs through pattern recognition receptors, endogenous/exogenous pathways, and the presentation of antigens through peptide/major histocompatibility complexes. Third, we reviewed how interactions between DCs and T cells coordinate immune homeostasis in vivo via multiple pathways. Finally, we summarized the application of DC-based immunotherapy for autoimmune diseases and tumors and highlighted potential research prospects for immunotherapy that targets DCs. This review provides a useful resource to better understand the immunomodulatory signals involved in different subsets of DCs and the manipulation of these immune signals can facilitate DC-based immunotherapy.

Dendritic cell vaccines in breast cancer: Immune modulation and immunotherapy

Breast cancer (BC) is the most common cancer in women worldwide. Although substantial progress has been made in the diagnosis and treatment of breast cancer, the efficacy and side effects of traditional treatment methods are still unsatisfactory. In recent years, immunotherapy including tumor vaccine has achieved great success in the treatment of BC. Dendritic cells (DCs) are multifunctional antigen-presenting cells that play an important role in the initiation and regulation of innate and adaptive immune responses. Numerous studies have shown that DC-based treatments might have a potential effect on BC. Among them, the clinical study of DC vaccine in BC has demonstrated considerable anti-tumor effect, and some DC vaccines have entered the stage of clinical trials. In this review, we summarize the immunomodulatory effects and related mechanisms of DC vaccine in breast cancer as well as the progress of clinical trials to propose possible challenges of DC vaccines and new development directions.

Inflammation, Infiltration, and Evasion-Tumor Promotion in the Aging Breast

Breast cancer is a significant cause of morbidity and mortality in women, with over two million new cases reported worldwide each year, the majority of which occur in post-menopausal women. Despite advances in early detection and treatment, approximately one-third of patients diagnosed with breast cancer will develop metastatic disease. The pathogenesis and progression of breast cancer are influenced by a variety of biological and social risk factors, including age, ethnicity, pregnancy status, diet, and genomic alterations. Recent advancements in breast cancer research have focused on harnessing the power of the patient's adaptive and innate immune systems for diagnostic and therapeutic purposes. The breast immune microenvironment plays a critical role in regulating tissue homeostasis and resistance to tumorigenesis. In this review, we explore the dynamic changes in the breast immune microenvironment that occur with age, how these changes impact breast cancer development and progression, and how targeted therapeutic interventions that leverage the immune system can be used to improve patient outcomes. Our review emphasizes the importance of understanding the complex interplay between aging, the immune system, and breast cancer, and highlights the potential of immune-based therapies in the fight against this devastating disease.

CD4+ T cells in cancer

Cancer immunology and immunotherapy are driving forces of research and development in oncology, mostly focusing on CD8⁺ T cells and the tumor microenvironment. Recent progress highlights the importance of CD4⁺ T cells, corresponding to the long-known fact that CD4⁺ T cells are central players and coordinators of innate and antigen-specific immune responses. Moreover, they have now been recognized as anti-tumor effector cells in their own right. Here we review the current status of CD4⁺ T cells in cancer, which hold great promise for improving knowledge and therapies in cancer.

Immunotherapies against HER2-Positive Breast Cancer

Breast cancer is the leading cause of cancer-related deaths among women worldwide. HER2-positive breast cancer, which represents 15-20% of all cases, is characterized by the overexpression of the HER2 receptor. Despite the variety of treatments available for HER2-positive breast cancer, both targeted and untargeted, many patients do not respond to therapy and relapse and eventually metastasize, with a poor prognosis. Immunotherapeutic approaches aim to enhance the antitumor immune response to prevent tumor relapse and metastasis. Several immunotherapies have been approved for solid tumors, but their utility for HER2-positive breast cancer has yet to be confirmed. In this review, we examine the different immunotherapeutic strategies being tested in HER2-positive breast cancer, from long-studied cancer vaccines to immune checkpoint blockade, which targets immune checkpoints in both T cells and tumor cells, as well as the promising adoptive cell therapy in various forms. We discuss how some of these new approaches may contribute to the prevention of tumor progression and be used after standard-of-care therapies for resistant HER2-positive breast tumors, highlighting the benefits and drawbacks of each. We conclude that immunotherapy holds great promise for the treatment of HER2-positive tumors, with the potential to completely eradicate tumor cells and prevent the progression of the disease.

Targeting HER2-positive breast cancer: advances and future directions

The long-sought discovery of HER2 as an actionable and highly sensitive therapeutic target was a major breakthrough for the treatment of highly aggressive HER2-positive breast cancer, leading to approval of the first HER2-targeted drug - the monoclonal antibody trastuzumab - almost 25 years ago. Since then, progress has been swift and the impressive clinical activity across multiple trials with monoclonal antibodies, tyrosine kinase inhibitors and antibody-drug conjugates that target HER2 has spawned extensive efforts to develop newer platforms and more targeted therapies. This Review discusses the current standards of care for HER2-positive breast cancer, mechanisms of resistance to HER2-targeted therapy and new therapeutic approaches and agents, including strategies to harness the immune system.

Innovative Therapeutic Approaches for Patients with HER2-Positive Breast Cancer

Overexpression of human epidermal growth factor receptor 2 (HER2), a transmembrane tyrosine kinase receptor, has been described in about 15-20% of breast cancer (BC) and is associated with poor outcomes. Trastuzumab is the first anti-HER2 monoclonal antibody (mAB) that blocks receptor activity but it also activates immune response against cancer cells, thus, revolutionizing the prognosis of patients with HER2-positive BC. Over the years, new therapies have been developed, including other mAbs and tyrosine kinase inhibitors (TKIs) that required multimodal approaches with chemotherapy to optimize their anticancer activity. This chapter gives a comprehensive overview of the last advancements including new approaches and future combinations, which seem to be very promising in overcoming resistance to the traditional anti-HER2 treatments. A modern therapeutic algorithm should include treatment options based on tumour patterns and a patient-centred approach. A proper patient's selection is crucial to derive maximal benefits from a treatment strategy and emerging biomarkers should be integrated along with the HER2 status, which is currently the only validated biomarker in the context of HER2-positive disease. These biomarkers might include molecular features with reported prognostic/predictive significance, such as phosphatidylinositol 3' -kinase (PI3K) or mitogen-activated protein kinase (MAPK) pathways, programmed cell death protein ligand 1 (PD-L1), and tumour-infiltrating lymphocytes (TILs), which all affect prognosis and response to treatments.

A Winning New Combination? Toward Clinical Application in Oncology

Immunotherapy has substantial attention in oncology due to the success of CTLA-4 and PD-1 inhibitors in the treatment of melanoma, lung cancer, head and neck cancer, renal cell carcinoma, and Hodgkin's lymphoma. A deeper understanding of interaction of tumor with its environment and the immune system provides best guide for oncology research. Recent studies in oncology have explained how a tumor alters antigen presentation, avoids detection, and activation of the host immune system to live and develop. Understanding the connections between the tumor and the immune system has resulted in several innovative therapy options. The extensive field of gene therapy has provided a number of cutting-edge medicines that are expected to play an important role in lowering cancer-related mortality. This article explains the history, important breakthroughs, and future prospects for three separate gene therapy treatment modalities: immunotherapy, oncolytic virotherapy, and gene transfer. Immunotherapies have completely changed how cancer is treated, especially for individuals whose condition was previously thought to be incurable. Examples include ACT (adoptive cell therapy) and ICB (immune checkpoint blockade). This review article will discuss the relationship between the immune response to cancer and the mechanisms of immunotherapy resistance. It will cover combination drugs authorized by the US Food and Drug Administration and provide a thorough overview of how these drugs are doing clinically right now. Cytokines, vaccines, and other soluble immunoregulatory agents, innate immune modifiers, ACT, virotherapy, and other treatment modalities will all be covered in detail.

Optimizing adjuvant and post-neoadjuvant therapy in HER2-positive early breast cancer

INTRODUCTION

Treatment advances have improved outcomes in human epidermal growth factor receptor 2 (HER2)-positive early-stage breast cancer (eBC) but certain patients remain at high risk of recurrence. Neoadjuvant therapy (NAT) has comparable outcomes to adjuvant therapy with the advantage of surgical down-staging, response assessment, informing prognosis, and tailoring adjuvant treatment. Thus, the standard of care for the majority of HER2-positive eBC has become a combination of chemotherapy and HER2-targeted agents given in the neoadjuvant setting.

AREAS COVERED

Mounting evidence suggests that pathologic complete response after NAT translates to a favorable long-term prognosis. The efficacy and tolerability of post-NAT are key, particularly for patients with residual disease. This is demonstrated, for example, by the use of trastuzumab emtansine in the appropriate clinical setting and various new drugs under investigation. This review summarizes the current clinical management and exciting future directions to optimize outcomes in HER2-positive eBC.

EXPERT OPINION

Targeted therapies such as trastuzumab deruxtecan, tucatinib, and immunotherapy have demonstrated impressive responses in metastatic breast cancer, including CNS disease. Incorporating these agents in the post-neoadjuvant space may improve the prognosis of HER2-positive eBC. Future research should prioritize the identification of biomarkers that personalize treatments to achieve maximum benefit and less toxicity.

Tumor-Infiltrating Dendritic Cells: Decisive Roles in Cancer Immunosurveillance, Immunoediting, and Tumor T Cell Tolerance

The tumor microenvironment plays a key role in progression of tumorigenesis, tumor progression, and metastasis. Accumulating data reveal that dendritic cells (DCs) appear to play a key role in the development and progression of metastatic neoplasia by driving immune system dysfunction and establishing immunosuppression, which is vital for tumor evasion of host immune response. Consequently, in this review, we will discuss the function of tumor-infiltrating DCs in immune cell signaling pathways that lead to treatment resistance, tumor recurrence, and immunosuppression. We will also review DC metabolism, differentiation, and plasticity, which are essential for metastasis and the development of lung tumors. Furthermore, we will take into account the interaction between myeloid cells and DCs in tumor-related immunosuppression. We will specifically look into the molecular immune-related mechanisms in the tumor microenvironment that result in reduced drug sensitivity and tumor relapse, as well as methods for combating drug resistance and focusing on immunosuppressive tumor networks. DCs play a crucial role in modulating the immune response. Especially, as cancer progresses, DCs may switch from playing an immunostimulatory to an inhibitory role. This article’s main emphasis is on tumor-infiltrating DCs. We address how they affect tumor growth and expansion, and we highlight innovative approaches for therapeutic modulation of these immunosuppressive DCs which is necessary for future personalized therapeutic approaches.

The modulatory role of dendritic cell-T cell cross-talk in breast cancer: Challenges and prospects

Antigen recognition and presentation are highlighted as the first steps in developing specialized antigen responses. Dendritic cells (DCs) are outstanding professional antigen-presenting cells (APCs) responsible for priming cellular immunity in pathological states, including cancer. However, the diminished or repressed function of DCs is thought to be a substantial mechanism through which tumors escape from the immune system. In this regard, DCs obtained from breast cancer (BC) patients represent a notably weakened potency to encourage specific T-cell responses. Additionally, impaired DC-T-cell cross-talk in BC facilitates the immune evade of cancer cells and is connected with tumor advancement, immune tolerance, and adverse prognosis for patients. In this review we aim to highlight the available knowledge on DC-T-cell interactions in BC aggressiveness and show its therapeutic potential in BC treatment.

Phase I/II clinical trial of a helper peptide vaccine plus PD-1 blockade in PD-1 antibody-naïve and PD-1 antibody-experienced patients with melanoma (MEL64)

BACKGROUND

A vaccine containing 6 melanoma-associated peptides to stimulate helper T cells (6MHP) is safe, immunogenic, and clinically active. A phase I/II trial was designed to evaluate safety and immunogenicity of 6MHP vaccines plus programmed death 1 (PD-1) blockade.

PARTICIPANTS AND METHODS

Participants with advanced melanoma received 6MHP vaccines in an incomplete Freund's adjuvant (6 vaccines over 12 weeks). Pembrolizumab was administered intravenously every 3 weeks. Tumor biopsies at baseline and day 22 were analyzed by multiplex immunohistochemistry. Primary end points were safety (Common Terminology Criteria for Adverse Events V.4.03) and immunogenicity (ex vivo interferon-γ ELISpot assay). Additional end points included changes in the tumor microenvironment (TME) and clinical outcomes.

RESULTS

Twenty-two eligible participants were treated: 6 naïve to PD-1 antibody (Ab) and 16 PD-1 Ab-experienced. Median follow-up was 24.4 months. Most common treatment-related adverse events (any grade) included injection site reactions, fatigue, anemia, lymphopenia, fever, elevated aspartate aminotransferase, pruritus, and rash. Treatment-related dose-limiting toxicities were observed in 3 (14%) participants, which did not cross the study safety bound. A high durable T cell response (Rsp) to 6MHP was detected in only one participant, but twofold T cell Rsps to 6MHP were detected in 7/22 (32%; 90% CI (16% to 52%)) by week 13. Objective clinical responses were observed in 23% (1 complete response, 4 partial responses), including 4/6 PD-1 Ab-naïve (67%) and 1/16 PD-1 Ab-experienced (6%). Overall survival (OS) was longer for PD-1 Ab-naïve than Ab-experienced participants (HR 6.3 (90% CI (2.1 to 28.7)). In landmark analyses at 13 weeks, OS was also longer for those with T cell Rsps (HR 6.5 (90% CI (2.1 to 29.2)) and for those with objective clinical responses. TME evaluation revealed increased densities of CD8+ T cells, CD20+ B cells, and Tbet+ cells by day 22.

CONCLUSIONS

Treatment with the 6MHP vaccine plus pembrolizumab was safe, increased intratumoral lymphocytes, and induced T cell Rsps associated with prolonged OS. The low T cell Rsp rate in PD-1 Ab-experienced participants corroborates prior murine studies that caution against delaying cancer vaccines until after PD-1 blockade. The promising objective response rate and OS in PD-1 Ab-naïve participants support consideration of a larger study in that setting.

Antigen transfer and its effect on vaccine-induced immune amplification and tolerance

Antigen transfer refers to the process of intercellular information exchange, where antigenic components including nucleic acids, antigen proteins/peptides and peptide-major histocompatibility complexes (p-MHCs) are transmitted from donor cells to recipient cells at the thymus, secondary lymphoid organs (SLOs), intestine, allergic sites, allografts, pathological lesions and vaccine injection sites via trogocytosis, gap junctions, tunnel nanotubes (TNTs), or extracellular vesicles (EVs). In the context of vaccine inoculation, antigen transfer is manipulated by the vaccine type and administration route, which consequently influences, even alters the immunological outcome, i.e., immune amplification and tolerance. Mainly focused on dendritic cells (DCs)-based antigen receptors, this review systematically introduces the biological process, molecular basis and clinical manifestation of antigen transfer.

Current State of Cell Therapies for Breast Cancer

Metastatic breast cancer (BC) is an aggressive form of cancer and is an absolute challenge to treat. This review discusses the standard treatments available for metastatic BC. It further highlights the rationale for targeting oncodrivers, tumor-associated antigens, and neoantigens in BC. Explaining the significance of immune response in successful immunotherapeutic studies, it draws attention towards how adoptive cell therapy can be a useful immunotherapeutic tool. We focus on adoptive cell therapy in BC covering tumor-infiltrating lymphocyte therapy, engineered T cell receptor therapy, chimeric antigen receptor therapy, dendritic cell therapy and natural killer cell therapy. In this work, we aim to provide an overview of clinical data regarding the use of cellular immunotherapies in BC. Eventually, we conclude by proposing future adoptive cell therapy approaches, which can be used to cure BC.

Immunological Landscape of HER-2 Positive Breast Cancer

Understanding the biological aspects of immune response in HER2+ breast cancer is crucial to implementing new treatment strategies in these patients. It is well known that anti-HER2 therapy has improved survival in this population, yet a substantial percentage may relapse, creating a need within the scientific community to uncover resistance mechanisms and determine how to overcome them. This systematic review indicates the immunological mechanisms through which trastuzumab and other agents target cancer cells, also outlining the main trials studying immune checkpoint blockade. Finally, we report on anti-HER2 vaccines and include a figure exemplifying their mechanisms of action.

Multidrug Resistance in Cancer: Understanding Molecular Mechanisms, Immunoprevention and Therapeutic Approaches

Cancer is one of the leading causes of death worldwide. Several treatments are available for cancer treatment, but many treatment methods are ineffective against multidrug-resistant cancer. Multidrug resistance (MDR) represents a major obstacle to effective therapeutic interventions against cancer. This review describes the known MDR mechanisms in cancer cells and discusses ongoing laboratory approaches and novel therapeutic strategies that aim to inhibit, circumvent, or reverse MDR development in various cancer types. In this review, we discuss both intrinsic and acquired drug resistance, in addition to highlighting hypoxia- and autophagy-mediated drug resistance mechanisms. Several factors, including individual genetic differences, such as mutations, altered epigenetics, enhanced drug efflux, cell death inhibition, and various other molecular and cellular mechanisms, are responsible for the development of resistance against anticancer agents. Drug resistance can also depend on cellular autophagic and hypoxic status. The expression of drug-resistant genes and the regulatory mechanisms that determine drug resistance are also discussed. Methods to circumvent MDR, including immunoprevention, the use of microparticles and nanomedicine might result in better strategies for fighting cancer.

Intratumoral delivery of dendritic cells plus anti-HER2 therapy triggers both robust systemic antitumor immunity and complete regression in HER2 mammary carcinoma

Background

Human epidermal growth factor receptor 2 (HER2) targeted antibodies in combination with chemotherapy has improved outcomes of HER2 positive (pos) breast cancer (BC) but toxicity of therapy remains a problem. High levels of tumor-infiltrating lymphocytes are associated with increased pathologic complete responses for patients treated with neoadjuvant therapy. Here we sought to investigate whether delivery of intratumoral (i.t.) multiepitope major histocompatibility complex (MHC) class II HER2 peptides-pulsed type I polarized dendritic cells (HER2-DC1) in combination with anti-HER2 antibodies without chemotherapy could enhance tumor regression by increasing anti-HER2 lymphocyte infiltration into the tumor.

Methods

BALB/c mice bearing orthotopic TUBO tumors, BALB/c mice bearing subcutaneous (s.c.) CT26 hHER2 tumors, or BALB-HER2/neu transgenic mice were all treated with i.t. or s.c. HER2-DC1, anti-HER2 antibodies, paclitaxel, T-DM1 or in combination. Immune response, host immune cells and effector function were analyzed using flow cytometry, interferon-γ ELISA and cytokine/chemokine arrays. The contributions of CD4⁺ and CD8⁺ T cells and antibody dependent cellular cytotoxicity (ADCC) were assessed using depleting antibodies and FcγR KO mice. Molecular changes were evaluated by immunohistochemistry and western blot.

Results

HER2-DC1 combined with anti-HER2 antibodies delivered i.t. compared to s.c. induced complete tumor regression in 75–80% of treated mice, with increased tumor infiltrating CD4⁺ and CD8⁺ T, B, natural killer T cells (NKT) and natural killer cells, and strong anti-HER2 responses in all HER2^pos BC models tested. The therapy caused regression of untreated distant tumors. Labeled HER2-DC1 migrated prominently into the distant tumor and induced infiltration of various DC subsets into tumors. HER2-DC1 i.t. combined with anti-HER2 antibodies displayed superior antitumor response compared to standard chemotherapy with anti-HER2 antibodies. Lasting immunity was attained which prevented secondary tumor formation. The presence of CD4⁺ and CD8⁺ T cells and ADCC were required for complete tumor regression. In the HER2^pos BC models, HER2-DC1 i.t. combined with anti-HER2 antibodies effectively diminished activation of HER2-mediated oncogenic signaling pathways.

Conclusions

HER2-DC1 i.t. with anti-HER2 antibodies mediates tumor regression through combined activation of T and B cell compartments and provides evidence that HER2-DC1 i.t. in combination with anti-HER2 antibodies can be tested as an effective alternative therapeutic strategy to current chemotherapy and anti-HER2 antibodies in HER2^pos BC.

Lymph Nodes as Anti-Tumor Immunotherapeutic Tools: Intranodal-Tumor-Specific Antigen-Pulsed Dendritic Cell Vaccine Immunotherapy

Simple Summary

In the field of cancer therapy, lymph nodes are important not only as targets for metastases resection but also as prudent target organs for cancer immunotherapy. Lymph nodes comprise a complete structure for the accumulation of a large number of T cells and their distribution throughout the body after antigen presentation and activation of dendritic cells. This review highlights current topics on the importance of lymph node structure in antitumor immunotherapy and intranodal-antigen-presenting mature dendritic cell vaccine therapy. We also discuss the rationale behind intranodal injection methods and their applications in neoantigen vaccine therapy, a new cancer immunotherapy.

Abstract

Hundreds of lymph nodes (LNs) are scattered throughout the body. Although each LN is small, it represents a complete immune organ that contains almost all types of immunocompetent and stromal cells functioning as scaffolds. In this review, we highlight the importance of LNs in cancer immunotherapy. First, we review recent reports on structural and functional properties of LNs as sites for antitumor immunity and discuss their therapeutic utility in tumor immunotherapy. Second, we discuss the rationale and background of ultrasound (US)-guided intranodal injection methods. In addition, we review intranodal administration therapy of tumor-specific-antigen-pulsed matured dendritic cells (DCs), including neoantigen-pulsed vaccines.

Is conservative management of ductal carcinoma in situ risky?

Nonsurgical management of ductal carcinoma in situ is controversial and little is known about the long-term consequences of this approach. In this study, we aimed to determine the risk of (a) upstaging to invasive carcinoma at excision and (b) ipsilateral breast cancer events in patients who might have been eligible for nonsurgical management of DCIS trials. Data from women aged 20 years or older with a biopsy diagnosis of DCIS between January 1, 2010 to December 31, 2014 were collated. The women underwent biopsy and surgical resection (lumpectomy or mastectomy) and were treated with radiation or endocrine therapy as per treating physicians’ choice. The development of ipsilateral breast cancer events (IBEs) was analyzed in patients with at least 5 years of follow-up after standard of care therapy for DCIS. Subset-analysis was undertaken to identify the incidence of IBEs in patients eligible for nonsurgical management trials. The study population consisted of 378 patients with matched cases of biopsy and surgical excision. The overall upstaging rate to IBC was 14.3 and 12.9% for COMET, 8.8% for LORIS, and 10.7% for LORD trial “eligible” patients. At 5 years of follow-up, ~11.5% of overall and trial eligible patients developed IBEs of which approximately half were invasive IBEs. In conclusion, women with DCIS who would have been eligible for nonsurgical management trials have a significantly high risk of developing ipsilateral breast events within 5 years of diagnosis. Better selection criteria are needed to identify DCIS patients who are at very low risk for the development of IBC.

Epigenetics of Dendritic Cells in Tumor Immunology

Dendritic cells (DCs) are professional antigen-presenting cells with the distinctive property of inducing the priming and differentiation of naïve CD4+ and CD8+ T cells into helper and cytotoxic effector T cells to develop efficient tumor-immune responses. DCs display pathogenic and tumorigenic antigens on their surface through major histocompatibility complexes to directly influence the differentiation of T cells. Cells in the tumor microenvironment (TME), including cancer cells and other immune-infiltrated cells, can lead DCs to acquire an immune-tolerogenic phenotype that facilitates tumor progression. Epigenetic alterations contribute to cancer development, not only by directly affecting cancer cells, but also by their fundamental role in the differentiation of DCs that acquire a tolerogenic phenotype that, in turn, suppresses T cell-mediated responses. In this review, we focus on the epigenetic regulation of DCs that have infiltrated the TME and discuss how knowledge of the epigenetic control of DCs can be used to improve DC-based vaccines for cancer immunotherapy.

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.

Peripheral Blood Transcriptome in Breast Cancer Patients as a Source of Less Invasive Immune Biomarkers for Personalized Medicine, and Implications for Triple Negative Breast Cancer

Transcriptome studies of peripheral blood cells can advance our understanding of the systemic immune response to the presence of cancer and the mechanisms underlying cancer onset and progression. This enables the identification of novel minimally invasive immune biomarkers for early cancer detection and personalized cancer management and may bring forward new immunotherapy options. Recent blood gene expression analyses in breast cancer (BC) identified distinct patient subtypes that differed in the immune reaction to cancer and were distinct from the clinical BC subtypes, which are categorized based on expression of specific receptors on tumor cells. Introducing new BC subtypes based on peripheral blood gene expression profiles may be appropriate, since it may assist in BC prognosis, the identification of patients likely to benefit from immunotherapy, and treatment efficacy monitoring. Triple-negative breast cancer (TNBC) is an aggressive, heterogeneous, and difficult-to-treat disease, and identification of novel biomarkers for this BC is crucial for clinical decision-making. A few studies have reported TNBC-enriched blood transcriptional signatures, mostly related to strong inflammation and augmentation of altered immune signaling, that can differentiate TNBC from other classical BC subtypes and facilitate diagnosis. Future research is geared toward transitioning from expression signatures in unfractionated blood cells to those in immune cell subpopulations.

Harnessing Antitumor CD4+ T Cells for Cancer Immunotherapy

Simple Summary

Diverse evidence revealed that CD4⁺ T cells play an important role in antitumor immunity by promoting or suppressing cytotoxic T cell responses. This review outlines the role of CD4⁺ T subsets within the tumor microenvironment and summarizes the latest progress regarding their potentials in cancer immunotherapy and methods for improving outcomes in cancer strategies by modulating CD4⁺ T responses.

Abstract

Over the past decades, CD4⁺ T cells have been considered as a supporting actor in the fields of cancer immunotherapy. Until recently, accumulating evidence has demonstrated the critical role of CD4⁺ T cells during antitumor immunity. CD4⁺ T cells can either suppress or promote the antitumor cytotoxic CD8⁺ T cell responses, either in secondary lymphoid organs or in the tumor. In this review, we provide an overview of the multifaceted role of different CD4⁺ T cell subsets in cancer immune response and their contribution during cancer therapies. Specifically, we focus on the latest progress regarding the impact of CD4⁺ T cell modulation on immunotherapies and other cancer therapies and discuss the prospect for harnessing CD4⁺ T cells to control tumor progression and prevent recurrence in patients.

Identification of Immunogenic MHC Class II Human HER3 Peptides that Mediate Anti-HER3 CD4+ Th1 Responses and Potential Use as a Cancer Vaccine

The HER3/ERBB3 receptor is an oncogenic receptor tyrosine kinase that forms heterodimers with EGFR family members and is overexpressed in numerous cancers. HER3 overexpression associates with reduced survival and acquired resistance to targeted therapies, making it a potential therapeutic target in multiple cancer types. Here, we report on immunogenic, promiscuous MHC class II-binding HER3 peptides, which can generate HER3-specific CD4⁺ Th1 antitumor immune responses. Using an overlapping peptide screening methodology, we identified nine MHC class II-binding HER3 epitopes that elicited specific Th1 immune response in both healthy donors and breast cancer patients. Most of these peptides were not identified by current binding algorithms. Homology assessment of amino acid sequence BLAST showed >90% sequence similarity between human and murine HER3/ERBB3 peptide sequences. HER3 peptide-pulsed dendritic cell vaccination resulted in anti-HER3 CD4⁺ Th1 responses that prevented tumor development, significantly delayed tumor growth in prevention models, and caused regression in multiple therapeutic models of HER3-expressing murine tumors, including mammary carcinoma and melanoma. Tumors were robustly infiltrated with CD4⁺ T cells, suggesting their key role in tumor rejection. Our data demonstrate that class II HER3 promiscuous peptides are effective at inducing HER3-specific CD4⁺ Th1 responses and suggest their applicability in immunotherapies for human HER3-overexpressing tumors.

Cancer vaccines as a targeted immunotherapy approach for breast cancer: an update of clinical evidence

INTRODUCTION

Breast cancer (BC) is the first common neoplastic malignancy and the second leading cause of death in women worldwide. Conventional treatments for BC are often associated with severe side effects and may even lead to late recurrence. For this reason, in recent years, cancer immunotherapy (e.g., cancer vaccines), a novel approach based on the specificity and amplification of acquired immune responses, has been considered as a potential candidate in particular to treat metastatic BC.

AREAS COVERED

In this review, we summarize and discuss the recent development of therapeutic vaccines for BC, use of specific BC cellular antigens, antigen selection, and probable causes for their insufficient effectiveness.

EXPERT OPINION

Despite development of several different BC vaccines strategies including protein/peptide, dendritic cell, and genetic vaccines, until now, no BC vaccine has been approved for clinical use. Most of the current BC vaccines themselves fail to bring clinical benefit to BC patients and are applied in combination with radiotherapy, chemotherapy, or targeted therapy. It is hoped that with advances in our knowledge about tumor microenvironment and the development of novel combination strategies, the tumor immunosuppressive mechanisms can be overcome and prolonged immunologic and effective anti-tumor response can be developed in patients.

O-GlcNAcylation of Blimp-1 in lymphocytes inhibits its transcriptional function and is associated with migration and invasion of breast cancer cells

Lymphocyte infiltration is an important feature of cancer. There is a complex network of chemokines that influence the degree and phenotype of lymphocyte infiltration, as well as the growth, survival, migration and angiogenesis of tumor cells. High heterogeneity metastasis is a major obstacle to the treatment of breast cancer. Herein, we showed that O-GlcNAcylation of B lymphocyte-induced maturation protein-1 (Blimp-1) in lymphocytes inhibited the migration and invasion of breast cancer cells. It was found that Blimp-1 O-GlcNAcylation at Ser448 and Ser472 in lymphocytes promoted its nuclear localization, and blocked the bindings to three regions upstream of the ccl3l1 promoter to inhibit its expression. Decreased expression of CCL3L1 in lymphocytes not only decreased CCR5 expression in breast cancer cells, but also inhibited the membrane localization and activation of CCR5, thus blocking the migration and invasion of breast cancer cells in vitro. Therefore, O-GlcNAcylation of Blimp-1 in lymphocytes may serve as a new target for the treatment of metastatic breast cancer. Implications: This study reveals a new mechanism by which the lymphatic system promotes breast cancer cell metastasis.

The Immune Landscape of Breast Cancer: Strategies for Overcoming Immunotherapy Resistance

Simple Summary

Immunotherapy is a rapidly advancing field in breast cancer treatment, however, it encounters many obstacles that leave open gateways for breast cancer cells to resist novel immunotherapies. It is believed that the tumor microenvironment consisting of cancer, stromal, and immune cells as well as a plethora of tumor-promoting soluble factors, is responsible for the failure of therapeutic strategies in cancer, including breast tumors. Therefore, an in-depth understanding of key barriers to effective immunotherapy, focusing the research efforts on harnessing the power of the immune system, and thus, developing new strategies to overcome the resistance may contribute significantly to increase breast cancer patient survival. In this review, we discuss the latest reports regarding the strategies rendering the immunosuppressive tumor microenvironment more sensitive to immunotherapy in breast cancers, HER2-positive and triple-negative types of breast cancer, which are attractive from an immunotherapeutic point of view.

Abstract

Breast cancer (BC) has traditionally been considered to be not inherently immunogenic and insufficiently represented by immune cell infiltrates. Therefore, for a long time, it was thought that the immunotherapies targeting this type of cancer and its microenvironment were not justified and would not bring benefits for breast cancer patients. Nevertheless, to date, a considerable number of reports have indicated tumor-infiltrating lymphocytes (TILs) as a prognostic and clinically relevant biomarker in breast cancer. A high TILs expression has been demonstrated in primary tumors, of both, HER2-positive BC and triple-negative (TNBC), of patients before treatment, as well as after treatment with adjuvant and neoadjuvant chemotherapy. Another milestone was reached in advanced TNBC immunotherapy with the help of the immune checkpoint inhibitors directed against the PD-L1 molecule. Although those findings, together with the recent developments in chimeric antigen receptor T cell therapies, show immense promise for significant advancements in breast cancer treatments, there are still various obstacles to the optimal activity of immunotherapeutics in BC treatment. Of these, the immunosuppressive tumor microenvironment constitutes a key barrier that greatly hinders the success of immunotherapies in the most aggressive types of breast cancer, HER2-positive and TNBC. Therefore, the improvement of the current and the demand for the development of new immunotherapeutic strategies is strongly warranted.

Strategy and clinical application of up-regulating cross presentation by DCs in anti-tumor therapy

The cross presentation of exogenous antigen (Ag) by dendritic cells (DCs) facilitates a diversified mode of T-cell activation, orchestrates specific humoral and cellular immunity, and contributes to an efficient anti-tumor immune response. DCs-mediated cross presentation is subject to both intrinsic and extrinsic factors, including the homing and phenotype of DCs, the spatiotemporal trafficking and degradation kinetics of Ag, and multiple microenvironmental clues, with many details largely unexplored. Here, we systemically review the current mechanistic understanding and regulation strategies of cross presentation by heterogeneous DC populations. We also provide insights into the future exploitation of DCs cross presentation for a better clinical efficacy in anti-tumor therapy.

Dendritic cell therapy with CD137L-DC-EBV-VAX in locally recurrent or metastatic nasopharyngeal carcinoma is safe and confers clinical benefit

INTRODUCTION

Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC), and provides a target for a dendritic cell (DC) vaccine. CD137 ligand (CD137L) expressed on antigen presenting cells, costimulates CD137-expressing T cells, and reverse CD137L signaling differentiates monocytes to CD137L-DC, a type of DC, which is more potent than classical DC in stimulating T cells.

METHODS

In this phase I study, patients with locally recurrent or metastatic NPC were administered CD137L-DC pulsed with EBV antigens (CD137L-DC-EBV-VAX).

RESULTS

Of the 12 patients treated, 9 received full 7 vaccine doses with a mean administered cell count of 23.9 × 10⁶ per dose. Treatment was well tolerated with only 4 cases of grade 1 related adverse events. A partial response was obtained in 1 patient, and 4 patients are still benefitting from a progression free survival (PFS) of currently 2-3 years. The mean pre-treatment neutrophil: lymphocyte ratio was 3.4 and a value of less than 3 was associated with prolonged median PFS. Progressors were characterized by a high frequency of naïve T cells but a low frequency of CD8⁺ effector T cells while patients with a clinical benefit (CB) had a high frequency of memory T cells. Patients with CB had lower plasma EBV DNA levels, and a reduction after vaccination.

CONCLUSION

CD137L-DC-EBV-VAX was well tolerated. The use of CD137L-DC-EBV-VAX is demonstrated to be safe. Consistent results were obtained from all 12 patients, indicating that CD137L-DC-EBV-VAX induces an anti-EBV and anti-NPC immune response, and warranting further studies in patients post effective chemotherapy.

PRECIS

The first clinical testing of CD137L-DC, a new type of monocyte-derived DC, finds that CD137L-DC are safe, and that they can induce an immune response against Epstein-Barr virus-associated nasopharyngeal carcinoma that leads to tumor regression or prevents tumor progression.

Murine Dendritic Cells Grown in Serum-Free Culture Show Potent Therapeutic Activity when Loaded with Novel Th Epitopes in an Orthotopic Model of HER2pos Breast Cancer

Preferred methods for generating mouse dendritic cells (DC) would encompass qualities of consistency, high yield, and potent function. Serum-free culture is also highly desirable, since this is the standard for cell-based therapies used in humans. We report here a serum-free modification of a culture method generating mature, activated DCs from bone marrow precursors. This is achieved through a two-stage culture comprised of 6-day expansion in Flt3 ligand and IL-6 followed by brief differentiation in a medium containing GM-CSF and IL-4, with subsequent activation using TLR ligands ODN1826 and LPS. The serum-free DCs achieve yields and surface phenotype including IL-12p70 secretion similar to standard serum-replete cultures, display a capacity to sensitize in vivo against both MHC class I- and Class II-restricted antigens, and exhibit some aspects of "killer DC" function against tumor cells. We used these DCs to help identify novel CD4^pos Th epitopes on the rat ErbB2/HER-2 protein and demonstrated a subset of these as effective immunogens in a DC-based therapeutic model of HER-2^pos breast cancer in Balb/c mice, where they induced powerful Th1-polarized immune responses. This method represents a useful way to efficiently produce large numbers of murine dendritic cells with excellent in vivo function well-suited for use in experimental vaccine studies.

Autologous Dendritic Cells in Combination With Chemotherapy Restore Responsiveness of T Cells in Breast Cancer Patients: A Single-Arm Phase I/II Trial

Introduction

Animal studies and preclinical studies in cancer patients suggest that the induction of immunogenic cell death (ICD) by neoadjuvant chemotherapy with doxorubicin and cyclophosphamide (NAC-AC) recovers the functional performance of the immune system. This could favor immunotherapy schemes such as the administration of antigen-free autologous dendritic cells (DCs) in combination with NAC-AC to profit as cryptic vaccine immunogenicity of treated tumors.

Objective

To explore the safety and immunogenicity of autologous antigen-free DCs administered to breast cancer patients (BCPs) in combination with NAC-AC.

Materials and Methods

A phase I/II cohort clinical trial was performed with 20 BCPs treated with NAC-AC [nine who received DCs and 11 who did not (control group)]. The occurrence of adverse effects and the functional performance of lymphocytes from BCPs before and after four cycles of NAC-AC receiving DCs or not were assessed using flow cytometry and compared with that from healthy donors (HDs). Flow cytometry analysis using manual and automated algorithms led us to examine functional performance and frequency of different lymphocyte compartments in response to a stimulus in vitro. This study was registered at clinicaltrials.gov (NCT03450044).

Results

No grade II or higher adverse effects were observed associated with the transfer of DCs to patients during NAC-AC. Interestingly, in response to the in vitro stimulation, deficient phosphorylation of Zap70 and AKT proteins observed before chemotherapy in most patients’ CD4 T cells significantly recovered after NAC-AC only in patients who received DCs.

Conclusions

The transfer of autologous DCs in combination with NAC-AC in BCPs is a safe procedure. That, in BCPs, the administration of DCs in combination with NAC-AC favors the recovery of the functional capacity of T cells suggests that this combination may potentiate the adjuvant effect of ICD induced by NAC-AC on T cells and, hence, potentiate the immunogenicity of tumors as cryptic vaccines.

Transcriptomic Properties of HER2+ Ductal Carcinoma In Situ of the Breast Associate with Absence of Immune Cells

The identification of transcriptomic alterations of HER2+ ductal carcinoma in situ (DCIS) that are associated with the density of tumor-infiltrating lymphocytes (TILs) could contribute to optimizing choices regarding the potential benefit of immune therapy. We compared the gene expression profile of TIL-poor HER2+ DCIS to that of TIL-rich HER2+ DCIS. Tumor cells from 11 TIL-rich and 12 TIL-poor DCIS cases were micro-dissected for RNA isolation. The Ion AmpliSeq Transcriptome Human Gene Expression Kit was used for RNA sequencing. After normalization, a Mann-Whitney rank sum test was used to analyze differentially expressed genes between TIL-poor and TIL-rich HER2+ DCIS. Whole tissue sections were immunostained for validation of protein expression. We identified a 29-gene expression profile that differentiated TIL-rich from TIL-poor HER2+ DCIS. These genes included CCND3, DUSP10 and RAP1GAP, which were previously described in breast cancer and cancer immunity and were more highly expressed in TIL-rich DCIS. Using immunohistochemistry, we found lower protein expression in TIL-rich DCIS. This suggests regulation of protein expression at the posttranslational level. We identified a gene expression profile of HER2+ DCIS cells that was associated with the density of TILs. This classifier may guide towards more rationalized choices regarding immune-mediated therapy in HER2+ DCIS, such as targeted vaccine therapy.

Comparison of Radiation With or Without Concurrent Trastuzumab for HER2-Positive Ductal Carcinoma In Situ Resected by Lumpectomy: A Phase III Clinical Trial

PURPOSE

Preclinical studies report that trastuzumab (T) can boost radiotherapy (RT) effectiveness. The primary aim of the B-43 trial was to assess the efficacy of RT alone vs concurrent RT plus T in preventing recurrence of ipsilateral breast cancer (IBTR) in women with ductal carcinoma in situ (DCIS).

PATIENTS AND METHODS

Eligibility: Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1, DCIS resected by lumpectomy, known estrogen receptor (ER) and/or progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2) status by centralized testing. Whole-breast RT was given concurrently with T. Stratification was by menopausal status, adjuvant endocrine therapy plan, and nuclear grade. Definitive intent-to-treat primary analysis was to be conducted when either 163 IBTR events occurred or all accrued patients were on study ≥ 5 years.

RESULTS

There were 2,014 participants who were randomly assigned. Median follow-up time as of December 31, 2019, was 79.2 months. At primary definitive analysis, 114 IBTR events occurred: RT arm, 63 and RT plus T arm, 51 (hazard ratio [HR], 0.81; 95% CI, 0.56 to 1.17; P value = .26). There were 34 who were invasive: RT arm, 18 and RT plus T arm, 20 (HR, 1.11; 95% CI, 0.59 to 2.10; P value = .71). Seventy-six were DCIS: RT arm, 45 and RT plus T arm, 31 (HR, 0.68; 95% CI, 0.43 to 1.08; P value = .11). Annual IBTR event rates were: RT arm, 0.99%/y and RT plus T arm, 0.79%/y. The study did not reach the 163 protocol-specified events, so the definitive analysis was triggered by all patients having been on study for ≥ 5 years.

CONCLUSION

Addition of T to RT did not achieve the objective of 36% reduction in IBTR rate but did achieve a modest but statistically nonsignificant reduction of 19%. Nonetheless, this trial had negative results. Further exploration of RT plus T is needed in HER2-positive DCIS before its routine delivery in patients with DCIS resected by lumpectomy.

Tumour-infiltrating lymphocytes in non-invasive breast cancer: A systematic review and meta-analysis

Background

The role of tumour infiltrating lymphocytes (TILs) as a biomarker in non-invasive breast cancer is unclear. This meta-analysis assessed the prognostic impact of TIL levels in patients with non-invasive breast cancer.

Methods

Systematic literature search was performed to identify studies assessing local recurrence in patients with non-invasive breast cancer according to TIL levels (high vs. low). Subgroup analyses per local recurrence (invasive and non-invasive) were performed. Secondary objectives were the association between TIL levels and non-invasive breast cancer subtypes, age, grade and necrosis. Odds ratios (ORs) and 95% confidence intervals (CI) were extracted from each study and a pooled analysis was conducted with random-effect model.

Results

Seven studies (N = 3437) were included in the present meta-analysis. High-TILs were associated with a higher likelihood of local recurrence (invasive or non-invasive, N = 2941; OR 2.05; 95%CI, 1.03–4.08; p = 0.042), although with a lower likelihood of invasive local recurrence (N = 1722; OR 0.69; 95%CI, 0.49–0.99; p = 0.042). High-TIL levels were associated with triple-negative (OR 3.84; 95%CI, 2.23–6.61; p < 0.001) and HER2-positive (OR 6.27; 95%CI, 4.93–7.97; p < 0.001) subtypes, high grade (OR 5.15; 95%CI, 3.69–7.19; p < 0.001) and necrosis (OR 3.09; 95%CI, 2.33–4.10; p < 0.001).

Conclusions

High-TIL levels were associated with more aggressive tumours, a higher likelihood of local recurrence (invasive or non-invasive) but a lower likelihood of invasive local recurrence in patients with non-invasive breast cancer.

•

The prognostic role of TILs in non-invasive breast cancer is unknown.

•

We observed an association between high-TILs and local recurrence.

•

High-TILs were associated with triple-negative and HER2+ subtypes, high grade and necrosis.

•

Non-invasive lesions with aggressive characteristics may also be more immunogenic.

•

Patients with low-TILs showed a higher likelihood of presenting an invasive recurrence.

Differentiation and Regulation of TH Cells: A Balancing Act for Cancer Immunotherapy

Current success of immunotherapy in cancer has drawn attention to the subsets of T_H cells in the tumor which are critical for activation of anti-tumor response either directly by themselves or by stimulating cytotoxic T cell activity. However, presence of immunosuppressive pro-tumorigenic T_H subsets in the tumor milieu further contributes to the complexity of regulation of T_H cell-mediated immune response. In this review, we present an overview of the multifaceted positive and negative effects of T_H cells, with an emphasis on regulation of different T_H cell subtypes by various immune cells, and how a delicate balance of contradictory signals can influence overall success of cancer immunotherapy. We focus on the regulatory network that encompasses dendritic cell-induced activation of CD4⁺ T_H1 cells and subsequent priming of CD8⁺ cytotoxic T cells, along with intersecting anti-inflammatory and pro-tumorigenic T_H2 cell activity. We further discuss how other tumor infiltrating immune cells such as immunostimulatory T_H9 and T_fh cells, immunosuppressive T_reg cells, and the duality of T_H17 function contribute to tip the balance of anti- vs pro-tumorigenic T_H responses in the tumor. We highlight the developing knowledge of CD4⁺ T_H1 immune response against neoantigens/oncodrivers, impact of current immunotherapy strategies on CD4⁺ T_H1 immunity, and how opposing action of T_H cell subtypes can be explored further to amplify immunotherapy success in patients. Understanding the nuances of CD4⁺ T_H cells regulation and the molecular framework undergirding the balancing act between anti- vs pro-tumorigenic T_H subtypes is critical for rational designing of immunotherapies that can bypass therapeutic escape to maximize the potential of immunotherapy.

Targeting HER2 in breast cancer: new drugs and paradigms on the horizon

About 15-20% of all breast cancers (BCs) are defined human epidermal growth factor receptor 2 (HER2)-positive, based on the overexpression of HER2 protein and/or amplification of ERBB2 gene. Such alterations lead to a more aggressive behavior of the disease, but also predict response to treatments targeting HER2. Indeed, several anti-HER2 compounds have been developed and approved in the last two decades, significantly improving our ability to cure patients in the early setting, and greatly extending their survival in the advanced setting. However, recent evolutions in this field promise to improve outcomes even further, through advancements in established HER2-targeting strategies, as well as the exploration of novel strategies. In particular, the engineering of new antibody-drug conjugates, with higher drug-to-antibody ratios (DARs) and cleavable linkers, has already led to the development of a highly effective drug, namely trastuzumab deruxtecan, recently approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMA) for the treatment of advanced HER2-positive (HER2+) BC, and currently in study in the early setting. Moreover, the novel tyrosine kinase inhibitor tucatinib was recently approved by FDA and EMA, showing to improve survival of HER2+ advanced BC patients, particularly in those with brain metastasis. Immunotherapy is also being investigated in the HER2+ subtype, through immune-checkpoint inhibition, cancer vaccines and adoptive-cell therapies. Overall, the enlarging arsenal of promising anti-HER2 compounds is expected to deliver significant improvements in the prognosis of both early and advanced HER2+ BC in the years to come. Moreover, some of such agents are showing encouraging activity in the much wider population of HER2-low advanced BC patients, challenging current BC classifications. If confirmed, this new paradigm would potentially expand the population deriving benefit from HER2-targeted treatments to up to 70% of all advanced BC patients, leading to a revolution in current treatment algorithms, and possibly to a redefinition of HER2 classification.