Brachyury, a vaccine target, is overexpressed in triple-negative breast cancer

Therapeutic vulnerabilities in triple negative breast cancer: Stem-like traits explored within molecular classification

Triple Negative Breast Cancer (TNBC) is the most aggressive type of breast cancer (BC). Despite advances in the clinical management of TNBC, recurrence-related mortality remains a challenge. The stem-like phenotype of TNBC plays a significant role in the persistence of minimal disease residue after therapy. Individuals exhibiting stem-like characteristics are particularly prone to inducing malignant relapse accompanied by strong resistance. Therefore, stem-like traits have been broadly proposed as therapeutic vulnerabilities to treat TNBC and reduce recurrence. However, heterogeneity within TNBC often generally restricts the stability of the therapeutic efficacy. To understand the heterogeneity and manage TNBC more precisely, multiple TNBC subtyping categories have been reported, providing the basis for profile-according therapeutic regimens. To provide more insight into targeting stem-like traits to ablate TNBC and reduce recurrence in the context of heterogeneity, this paper reviewed the molecular subtyping of TNBC, identified the consensus subtypes with distinct stem-like phenotypes, characterized the stemness hierarchy of TNBC, outlined the biological models for stem-like TNBC subtypes, summarized the therapeutic vulnerabilities in stem-like traits of the subtypes, and proposed potential therapeutic regimens targeting stem-like characteristics to improve TNBC prognosis.

Unveiling the Immune Microenvironment's Role in Breast Cancer: A Glimpse into Promising Frontiers

Breast cancer (BC), one of the most widespread and devastating diseases affecting women worldwide, presents a significant public health challenge. This review explores the emerging frontiers of research focused on deciphering the intricate interplay between BC cells and the immune microenvironment. Understanding the role of the immune system in BC is critical as it holds promise for novel therapeutic approaches and precision medicine strategies. This review delves into the current literature regarding the immune microenvironment's contribution to BC initiation, progression, and metastasis. It examines the complex mechanisms by which BC cells interact with various immune cell populations, including tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs). Furthermore, this review highlights the impact of immune-related factors, such as cytokines and immune checkpoint molecules. Additionally, this comprehensive analysis sheds light on the potential biomarkers associated with the immune response in BC, enabling early diagnosis and prognostic assessment. The therapeutic implications of targeting the immune microenvironment are also explored, encompassing immunotherapeutic strategies and combination therapies to enhance treatment efficacy. The significance of this review lies in its potential to pave the way for novel therapeutic interventions, providing clinicians and researchers with essential knowledge to design targeted and personalized treatment regimens for BC patients.

Cancer Vaccines for Triple-Negative Breast Cancer: A Systematic Review

Triple-negative breast cancer (TNBC) is the subtype of breast cancer with the poorest outcomes, and is associated with a high risk of relapse and metastasis. The treatment choices for this malignancy have been confined to conventional chemotherapeutic agents, due to a lack of expression of the canonical molecular targets. Immunotherapy has been recently changing the treatment paradigm for many types of tumors, and the approach of evoking active immune responses in the milieu of breast tumors through cancer vaccines has been introduced as one of the most novel immunotherapeutic approaches. Accordingly, a number of vaccines for the treatment or prevention of recurrence have been developed and are currently being studied in TNBC patients, while none have yet received any approvals. To elucidate the efficacy and safety of these vaccines, we performed a systematic review of the available literature on the topic. After searching the PubMed, Scopus, Web of Science, Embase, Cochrane CENTRAL, and Google Scholar databases, a total of 5701 results were obtained, from which 42 clinical studies were eventually included based on the predefined criteria. The overall quality of the included studies was acceptable. However, due to a lack of reporting outcomes of survival or progression in some studies (which were presented as conference abstracts) as well as the heterogeneity of the reported outcomes and study designs, we were not able to carry out a meta-analysis. A total of 32 different vaccines have so far been evaluated in TNBC patients, with the majority belonging to the peptide-based vaccine type. The other vaccines were in the cell or nucleic acid (RNA/DNA)-based categories. Most vaccines proved to be safe with low-grade, local adverse events and could efficiently evoke cellular immune responses; however, most trials were not able to demonstrate significant improvements in clinical indices of efficacy. This is in part due to the limited number of randomized studies, as well as the limited TNBC population of each trial. However, due to the encouraging results of the currently published trials, we anticipate that this strategy could show its potential through larger, phase III randomized studies in the near future.

Knockdown of Brachyury Suppresses Breast Cancer Cell Proliferation and Migration via Targeting E2F3

Breast cancer is one of the most frequently diagnosed cancer in women and is the major cause of most cancer-related deaths. We previously reported that Brachyury, as a sensitive and specific marker, has been verified to involve in the process of carcinogenesis and progression of breast cancer, but the mechanism by which Brachyury promotes breast cancer cells proliferation and migration still remains less clear. In this study, we identified that Brachyury was markedly increased in breast cancer compared with the adjacent tissues. We have also shown that Brachyury knockdown could decrease the proliferation and migration capability in breast cancer cells both in vitro and in vivo. Finally, we found an important transcriptional factor, E2F3, which is a direct downstream target gene of Brachyury by chromatin immunoprecipitation (ChIP) analysis. Knockdown of E2F3 also decreased breast cancer cell proliferation and migration. Taken together, we reported that Brachyury may act as an oncogenic role in the progression of breast cancer by positively-regulating E2F3 expression.

Emerging target discovery and drug repurposing opportunities in chordoma

The development of effective and personalized treatment options for patients with rare cancers like chordoma is hampered by numerous challenges. Biomarker-guided repurposing of therapies approved in other indications remains the fastest path to redefining the treatment paradigm, but chordoma's low mutation burden limits the impact of genomics in target discovery and precision oncology efforts. As our knowledge of oncogenic mechanisms across various malignancies has matured, it's become increasingly clear that numerous properties of tumors transcend their genomes - leading to new and uncharted frontiers of therapeutic opportunity. In this review, we discuss how the implementation of cutting-edge tools and approaches is opening new windows into chordoma's vulnerabilities. We also note how a convergence of emerging observations in chordoma and other cancers is leading to the identification and evaluation of new therapeutic hypotheses for this rare cancer.

Breast Cancer Stem Cells: Signaling Pathways, Cellular Interactions, and Therapeutic Implications

Breast cancer stem cells (BCSCs) constitute a small population of cells within breast cancer and are characterized by their ability to self-renew, differentiate, and recapitulate the heterogeneity of the tumor. Clinically, BCSCs have been correlated with cancer progression, metastasis, relapse, and drug resistance. The tumorigenic roles of BCSCs have been extensively reviewed and will not be the major focus of the current review. Here, we aim to highlight how the crucial intrinsic signaling pathways regulate the fate of BCSCs, including the Wnt, Notch, Hedgehog, and NF-κB signaling pathways, as well as how different cell populations crosstalk with BCSCs within the TME, including adipocytes, endothelial cells, fibroblasts, and immune cells. Based on the molecular and cellular activities of BCSCs, we will also summarize the targeting strategies for BCSCs and related clinical trials. This review will highlight that BCSC development in breast cancer is impacted by both BCSC endogenous signaling and external factors in the TME, which provides an insight into how to establish a comprehensively therapeutic strategy to target BCSCs for breast cancer treatments.

Role of T-box genes in cancer, epithelial-mesenchymal transition, and cancer stem cells

Sharing a common DNA binding motif called T-box, transcription factor T-box gene family controls embryonic development and is also involved in cancer progression and metastasis. Cancer metastasis shows therapy resistance and involves complex processes. Among them, epithelial-mesenchymal transition (EMT) triggers cancer cell invasiveness and the acquisition of stemness of cancer cells, called cancer stem cells (CSCs). CSCs are a small fraction of tumor bulk and are capable of self-renewal and tumorsphere formation. Recent progress has highlighted the critical roles of T-box genes in cancer progression, EMT, and CSC function, and such regulatory functions of T-box genes have emerged as potential therapeutic candidates for cancer. Herein we summarize the current understanding of the regulatory mechanisms of T-box genes in cancer, EMT, and CSCs, and discuss the implications of targeting T-box genes as anticancer therapeutics.

Breast cancer immunotherapy: Current and novel approaches

The crucial role of the immune system in the progression/regression of breast cancer (BC) should always be taken into account. Various immunotherapy approaches have been investigated for BC, including tumor-targeting antibodies (bispecific antibodies), adoptive T cell therapy, vaccines, and immune checkpoint blockade such as anti-PD-1. In addition, a combination of conventional chemotherapy and immunotherapy approaches contributes to improving patients' overall survival rates. Although encouraging outcomes have been reported in most clinical trials of immunotherapy, some obstacles should still be resolved in this regard. Recently, personalized immunotherapy has been proposed as a potential complementary medicine with immunotherapy and chemotherapy for overcoming BC. Accordingly, this review discusses the brief association of these methods and future directions in BC immunotherapy.

Targeted Therapy for Chordoma: Key Molecular Signaling Pathways and the Role of Multimodal Therapy

BACKGROUND

Chordoma is a rare but devastating tumor that arises in the cranial skull base or spine. There are currently no US Food and Drug Administration-approved targeted therapies for chordoma, and little understanding of whether using more than one therapy has benefit over monotherapy.

OBJECTIVE

The objective of this study was to systematically review the current status of clinical trials completed for patients with chordoma to determine if multimodal therapy offers a benefit in progression-free survival over monomodal therapy.

METHODS

We performed a systematic review of the literature according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines to review the available clinical trials of targeted therapy for chordoma. We compiled the clinical data to determine if there is a benefit of multimodal therapy over monotherapy.

RESULTS

Our search resulted in 11 clinical trials including 270 patients with advanced chordoma who were treated with targeted therapies. The most commonly employed targeted therapies acted within the following pathways: platelet-derived growth factor receptor (187 patients), vascular endothelial growth factor (66 patients), and mammalian target of rapamycin (43 patients). Reported progression-free survival for included studies ranged from 2.5 to 58 months, with the longest progression-free survival in a trial that included a platelet-derived growth factor receptor inhibitor, nilotinib, and concurrent radiotherapy (58.2 months). There was a higher range of progression-free survival for trials treating patients with multimodal therapy (10.2-14 months vs 2.5-9.2 months, except for a monotherapy trial published in 2020 with a progression-free survival of 18 months), and those published in 2018 or later (14-58.2 months vs 2.5-10.2 months). Only 23% of patients with chordoma in published clinical trials have been treated with multimodal therapy.

CONCLUSIONS

Progression-free survival may be enhanced by the use of targeted therapy with concurrent radiotherapy, use of multimodal therapy, and use of newer targeted therapy. Future clinical trials should consider use of concurrent radiotherapy and multimodal therapy for patients with advanced chordoma.

Machine learning based tissue analysis reveals Brachyury has a diagnosis value in breast cancer

Background: The aim of the present study was to confirm the role of Brachyury in breast cancer and to verify whether four types of machine learning models can use Brachyury expression to predict the survival of patients.

Methods: We conducted a retrospective review of the medical records to obtain patient information, and made the patient’s paraffin tissue into tissue chips for staining analysis. We selected 303 patients for research and implemented four machine learning algorithms, including multivariate logistic regression model, decision tree, artificial neural network and random forest, and compared the results of these models with each other. Area under the receiver operating characteristic (ROC) curve (AUC) was used to compare the results.

Results: The chi-square test results of relevant data suggested that the expression of Brachyury protein in cancer tissues was significantly higher than that in paracancerous tissues (P=0.0335); patients with breast cancer with high Brachyury expression had a worse overall survival (OS) compared with patients with low Brachyury expression. We also found that Brachyury expression was associated with ER expression (P=0.0489). Subsequently, we used four machine learning models to verify the relationship between Brachyury expression and the survival of patients with breast cancer. The results showed that the decision tree model had the best performance (AUC = 0.781).

Conclusions: Brachyury is highly expressed in breast cancer and indicates that patients had a poor prognosis. Compared with conventional statistical methods, decision tree model shows superior performance in predicting the survival status of patients with breast cancer.

Improving the Odds in Advanced Breast Cancer With Combination Immunotherapy: Stepwise Addition of Vaccine, Immune Checkpoint Inhibitor, Chemotherapy, and HDAC Inhibitor in Advanced Stage Breast Cancer

Breast tumors commonly harbor low mutational burden, low PD-L1 expression, defective antigen processing/presentation, and an immunosuppressive tumor microenvironment (TME). In a malignancy mostly refractory to checkpoint blockade, there is an unmet clinical need for novel combination approaches that increase tumor immune infiltration and tumor control. Preclinical data have guided the development of this clinical trial combining 1) BN-Brachyury (a poxvirus vaccine platform encoding the tumor associated antigen brachyury), 2) bintrafusp alfa (a bifunctional protein composed of the extracellular domain of the TGF-βRII receptor (TGFβ "trap") fused to a human IgG1 anti-PD-L1), 3), entinostat (a class I histone deacetylase inhibitor), and 4) T-DM1 (ado-trastuzumab emtansine, a standard of care antibody-drug conjugate targeting HER2). We hypothesize that this tetratherapy will induce a robust immune response against HER2+ breast cancer with improved response rates through 1) expanding tumor antigen-specific effector T cells, natural killer cells, and immunostimulatory dendritic cells, 2) improving antigen presentation, and 3) decreasing inhibitory cytokines, regulatory T cells, and myeloid-derived suppressor cells. In an orthotopic HER2+ murine breast cancer model, tetratherapy induced high levels of antigen-specific T cell responses, tumor CD8+ T cell/Treg ratio, and augmented the presence of IFNγ- or TNFα-producing CD8+ T cells and IFNγ/TNFα bifunctional CD8+ T cells with increased cytokine production. Similar effects were observed in tumor CD4+ effector T cells. Based on this data, a phase 1b clinical trial evaluating the stepwise addition of BN-Brachyury, bintrafusp alfa, T-DM1 and entinostat in advanced breast cancer was designed. Arm 1 (TNBC) receives BN-Brachyury + bintrafusp alfa. Arm 2 (HER2+) receives T-DM1 + BN-Brachyury + bintrafusp alfa. After safety is established in Arm 2, Arm 3 (HER2+) will receive T-DM1 + BN-Brachyury + bintrafusp alfa + entinostat. Reimaging will occur every 2 cycles (1 cycle = 21 days). Arms 2 and 3 undergo research biopsies at baseline and after 2 cycles to evaluate changes within the TME. Peripheral immune responses will be evaluated. Co-primary objectives are response rate and safety. All arms employ a safety assessment in the initial six patients and a 2-stage Simon design for clinical efficacy (Arm 1 if ≥ three responses of eight then expand to 13 patients; Arms 2 and 3 if ≥ four responses of 14 then expand to 19 patients per arm). Secondary objectives include progression-free survival and changes in tumor infiltrating lymphocytes. Exploratory analyses include changes in peripheral immune cells and cytokines. To our knowledge, the combination of a vaccine, an anti-PD-L1 antibody, entinostat, and T-DM1 has not been previously evaluated in the preclinical or clinical setting. This trial (NCT04296942) is open at the National Cancer Institute (Bethesda, MD).

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.

The Roles of Embryonic Transcription Factor BRACHYURY in Tumorigenesis and Progression

Transcription factor brachyury, with a DNA-binding T-domain, regulates posterior mesoderm formation and notochord development through binding with highly conserved palindromic consensus sequence in a variety of organisms. The absence of brachyury expression in majority of adult normal tissues and exclusive tumor-specific expression provides the potential to be developed into a novel and promising diagnostic and therapeutic target in cancer. As a sensitive and specific marker in the diagnosis of chordoma, brachyury protein has been verified to involve in the process of carcinogenesis and progression of chordoma and several epithelial carcinomas in various studies, but the mechanism by which brachyury promotes tumor cells migrate, invade and metastasis still remains less clear. To this end, we attempt to summarize the literature on the upstream regulatory pathway of brachyury transcription and downstream controlling network by brachyury activation, all of which involve in both the embryonic development and tumor progression. We present the respective correlation of brachyury expression with tumor progression, distant metastasis, survival rate and prognosis in several types of tumor samples (including chordoma, lung cancer, breast carcinoma, and prostate cancer), and various brachyury gain-of-function and loss-of-function experiments are summarized to explore its specific role in respective tumor cell line in vitro. In addition, we also discuss another two programs relating to brachyury function: epithelial-to-mesenchymal transition (EMT) and cell cycle control, both of which implicate in the regulation of brachyury on biological behavior of tumor cells. This review will provide an overview of the function of master transcriptional factor brachyury, compare the similarities and differences of its role between embryonic development and carcinogenesis, and list the evidence on which brachyury-target therapies have the potential to help control advanced cancer populations.

Breast cancer metastasis to bone: From epithelial to mesenchymal transition to breast osteoblast-like cells

In this review we highlighted the newest aspects concerning the physiopathology of breast cancer metastatization into the bone including: a) in situ biomarkers of breast cancer metastatic diseases, b) biological processes related to the origin of metastatic cells (epithelial to mesenchymal transition), c) the nature and the possible role of Breast Osteoblast-Like Cells in the formation of bone lesions and d) the prognostic value of breast microcalcifications for the bone metastatic disease. In addition, the more recent data about the biology of breast cancer metastatic process and the origin and function of Breast Osteoblast-Like Cells have been analyzed to propose the use of molecular imaging investigations able to identify early neoplastic lesions with high propensity to form bone metastasis in vivo.

If we build it they will come: targeting the immune response to breast cancer

Historically, breast cancer tumors have been considered immunologically quiescent, with the majority of tumors demonstrating low lymphocyte infiltration, low mutational burden, and modest objective response rates to anti-PD-1/PD-L1 monotherapy. Tumor and immunologic profiling has shed light on potential mechanisms of immune evasion in breast cancer, as well as unique aspects of the tumor microenvironment (TME). These include elements associated with antigen processing and presentation as well as immunosuppressive elements, which may be targeted therapeutically. Examples of such therapeutic strategies include efforts to (1) expand effector T-cells, natural killer (NK) cells and immunostimulatory dendritic cells (DCs), (2) improve antigen presentation, and (3) decrease inhibitory cytokines, tumor-associated M2 macrophages, regulatory T- and B-cells and myeloid derived suppressor cells (MDSCs). The goal of these approaches is to alter the TME, thereby making breast tumors more responsive to immunotherapy. In this review, we summarize key developments in our understanding of antitumor immunity in breast cancer, as well as emerging therapeutic modalities that may leverage that understanding to overcome immunologic resistance.

Single peptides and combination modalities for triple negative breast cancer

Unlike other types of breast cancers (BCs), no specific therapeutic targets have been established for triple negative breast cancer (TNBC). Therefore, chemotherapy and radiotherapy are the only available adjuvant therapeutic choices for TNBC. New emerging reports show that TNBC is associated with higher numbers of intratumoral tumor infiltrating lymphocytes. This is indicative of host anti-TNBC immune surveillance and suggesting that immunotherapy can be considered as a therapeutic approach for TNBC management. Recent progress in molecular mechanisms of tumor-immune system interaction and cancer vaccine development studies, fast discoveries and FDA approvals of immune checkpoint inhibitors, chimeric antigen receptor T-cells, and oncolytic virotherapy have significantly attracted attention and research directions toward the immunotherapeutic approach to TNBC. Here in this review different aspects of TNBC immunotherapies including the host immune system-tumor interactions, the tumor microenvironment, the relevant molecular targets for immunotherapy, and clinical trials in the field are discussed.

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.

Immunotherapeutic interventions of Triple Negative Breast Cancer

Triple Negative Breast Cancer (TNBC) is a highly heterogeneous subtype of breast cancer that lacks the expression of oestrogen receptors, progesterone receptors and human epidermal growth factor receptor 2. Although TNBC is sensitive to chemotherapy, the overall outcomes of TNBC are worse than for other breast cancers, and TNBC is still one of the most fatal diseases for women. With the discovery of antigens specifically expressed in TNBC cells and the developing technology of monoclonal antibodies, chimeric antigen receptors and cancer vaccines, immunotherapy is emerging as a novel promising option for TNBC. This review is mainly focused on the tumour microenvironment and host immunity, Triple Negative Breast Cancer and the clinical treatment of TNBC, novel therapies for cancer and immunotherapy for TNBC, and the future outlook for the treatment for TNBC and the interplay between the therapies, including immune checkpoint inhibitors, combination of immune checkpoint inhibitors with targeted treatments in TNBC, adoptive cell therapy, cancer vaccines. The review also highlights recent reports on the synergistic effects of immunotherapy and chemotherapy, antibody-drug conjugates, and exosomes, as potential multifunctional therapeutic agents in TNBC.

Loss of the Cyclin-Dependent Kinase Inhibitor 1 in the Context of Brachyury-Mediated Phenotypic Plasticity Drives Tumor Resistance to Immune Attack

The acquisition of mesenchymal features by carcinoma cells is now recognized as a driver of metastasis and tumor resistance to a range of anticancer therapeutics, including chemotherapy, radiation, and certain small-molecule targeted therapies. With the recent successful implementation of immunotherapies for the treatment of various types of cancer, there is growing interest in understanding whether an immunological approach could be effective at eradicating carcinoma cells bearing mesenchymal features. Recent studies, however, demonstrated that carcinoma cells that have acquired mesenchymal features may also exhibit decreased susceptibility to lysis mediated by immune effector cells, including antigen-specific CD8⁺ T cells, innate natural killer (NK), and lymphokine-activated killer (LAK) cells. Here, we investigated the mechanism involved in the immune resistance of carcinoma cells that express very high levels of the transcription factor brachyury, a molecule previously shown to drive the acquisition of mesenchymal features by carcinoma cells. Our results demonstrate that very high levels of brachyury expression drive the loss of the cyclin-dependent kinase inhibitor 1 (p21CIP1, p21), an event that results in decreased tumor susceptibility to immune-mediated lysis. We show here that reconstitution of p21 expression markedly increases the lysis of brachyury-high tumor cells mediated by antigen-specific CD8⁺ T cells, NK, and LAK cells, TNF-related apoptosis-inducing ligand, and chemotherapy. Several reports have now demonstrated a role for p21 loss in cancer as an inducer of the epithelial–mesenchymal transition. The results from the present study situate p21 as a central player in many of the aspects of the phenomenon of brachyury-mediated mesenchymalization of carcinomas, including resistance to chemotherapy and immune-mediated cytotoxicity. We also demonstrate here that the defects in tumor cell death described in association with very high levels of brachyury could be alleviated via the use of a WEE1 inhibitor. Several vaccine platforms targeting brachyury have been developed and are undergoing clinical evaluation. These studies provide further rationale for the use of WEE1 inhibition in combination with brachyury-based immunotherapeutic approaches.

Prognostic significance of expression of epithelial-mesenchymal transition driver brachyury in breast cancer and its association with subtype and characteristics

Brachyury is a T-box transcription factor characterized as a driver of the epithelial-to-mesenchymal process, which is associated with poor prognosis of patients with breast cancer. The present study investigated expression of brachyury in breast cancer including primary tumor, metastatic and recurred tumor tissues, and the clinical significance and value of brachyury as a prognostic biomarker. This retrospective study included a series of 102 consecutive patients surgically resected between January 2005 and December 2011. Brachyury expression in tumor cell was evaluated using immunohistochemistry and scored as the immunoactivity. Of 102 patients, 62 primary tumors were positive for brachyury expression and 40 were negative. Multivariate analysis of disease-free survival (DFS) revealed brachyury expression, HER2 and lymphovascular invasion as independent prognostic factors [brachyury negative vs. positive hazard ratio (HR), 3.0; P=0.024; HER2 negative vs. positive HR, 4.9; P=0.003; lymphovascular invasion absent vs. present HR, 3.5; P=0.020]. These results were particularly observed in triple-negative breast cancer (TNBC), no recurrence or mortality occurred in brachyury negative group during the follow-up period, and therefore a significantly improved prognosis was demonstrated in these patients compared with the brachyury positive group [overall survival (OS), P=0.022; DFS, P=0.002]. Brachyury expression in metastatic lymph node/recurred tumors was not significantly associated with prognosis (OS, P=0.745; DFS, P=0.189). Therefore, Brachyury expression in primary tumor independently is a potential predictor of poor prognosis, particularly in TNBC, where it appears to serve a crucial function in recurrence and mortality. Brachyury vaccines under clinical trials are likely to be useful in patients with breast cancer.

Phase I Study of a Poxviral TRICOM-Based Vaccine Directed Against the Transcription Factor Brachyury

Purpose: The transcription factor brachyury has been shown in preclinical studies to be a driver of the epithelial-to-mesenchymal transition (EMT) and resistance to therapy of human tumor cells. This study describes the characterization of a Modified Vaccinia Ankara (MVA) vector-based vaccine expressing the transgenes for brachyury and three human costimulatory molecules (B7.1, ICAM-1, and LFA-3, designated TRICOM) and a phase I study with this vaccine.Experimental Design: Human dendritic cells (DC) were infected with MVA-brachyury-TRICOM to define their ability to activate brachyury-specific T cells. A dose-escalation phase I study (NCT02179515) was conducted in advanced cancer patients (n = 38) to define safety and to identify brachyury-specific T-cell responses.Results: MVA-brachyury-TRICOM-infected human DCs activated CD8⁺ and CD4⁺ T cells specific against the self-antigen brachyury in vitro No dose-limiting toxicities were observed due to vaccine in cancer patients at any of the three dose levels. One transient grade 3 adverse event (AE) possibly related to vaccine (diarrhea) resolved without intervention and did not recur with subsequent vaccine. All other AEs related to vaccine were transient and ≤grade 2. Brachyury-specific T-cell responses were observed at all dose levels and in most patients.Conclusions: The MVA-brachyury-TRICOM vaccine directed against a transcription factor known to mediate EMT can be administered safely in patients with advanced cancer and can activate brachyury-specific T cells in vitro and in patients. Further studies of this vaccine in combination therapies are warranted and planned. Clin Cancer Res; 23(22); 6833-45. ©2017 AACR.

Combination therapy with an OX40L fusion protein and a vaccine targeting the transcription factor twist inhibits metastasis in a murine model of breast cancer

OX40 is a costimulatory receptor that potentiates proliferation, survival, memory formation, and effector function of CD4⁺ and CD8⁺ T-cells, while overcoming the suppressive activity of regulatory T-cells (Tregs). Here, we explored the combination of an OX40L fusion protein (OX40L-FP) with a poxvirus-based cancer vaccine (MVA-Twist-TRICOM) to inhibit tumor metastasis in the 4T1 murine breast cancer model. Contrary to the single agent treatments, the combination therapy significantly decreased the number of metastatic colonies per lung and prolonged survival. Depletion studies demonstrated that these effects were mediated by both CD4⁺ and CD8⁺ T-cells. The combination therapy a) increased the total number of T-cells in the CD4⁺Foxp3^- population and the CD4⁺ central and effector memory subsets within the lung, spleen, and draining lymph node, b) enhanced infiltration of CD4⁺ T-cells into metastatic areas of the lung, and (c) increased the number of functional CD8⁺ T-cells that produced IFNγ and TNFα. The combination therapy also promoted the development of KLRG1^-CD127⁺ memory precursor CD8⁺ T-cells, while reducing those with a KLRG1⁺ terminally differentiated phenotype. Moreover, the combination of OX40L-FP and vaccine induced greater CD4⁺ and CD8⁺ Twist-specific responses. In addition, Tregs isolated from mice receiving the combination were also less immunosuppressive in ex-vivo proliferation assays than those from the OX40L-FP and MVA-Twist-TRICOM monotherapy groups. Such results provide the rationale to combine co-stimulatory agonists with cancer vaccines for the treatment of tumor metastasis.

Expression of epithelial-mesenchymal transition driver brachyury and status of tumor-infiltrating CD8+ and FOXP3+ lymphocytes in predicting treatment responses to neoadjuvant chemotherapy of breast cancer

Brachyury has been characterized as a driver of epithelial-mesenchymal transition process which is regarded as an important mechanism of cancer cell invasion and metastatic progression. The status of tumor-infiltrating lymphocytes has been proposed to predict response to neoadjuvant chemotherapy in breast cancer. We investigated the clinical significance and value of tumor-infiltrating lymphocytes and brachyury as biomarkers to predict treatment responses to neoadjuvant chemotherapy in breast cancer. We also examined the correlation of the Neo-Bioscore with tumor-infiltrating lymphocytes and brachyury to indirectly predict long-term outcome. This retrospective study included a series of 44 consecutive patients treated between January 2011 and December 2015. All patient samples were obtained using core needle biopsy before neoadjuvant chemotherapy. The relationship of expression of Brachyury and tumor-infiltrating lymphocyte subsets (CD8+, forkhead box protein 3 tumor-infiltrating lymphocytes) with clinicopathological factors was assessed to identify its predictive role with respect to tumor response to neoadjuvant chemotherapy and the outcome. Of 44 patients, 6 showed no response, 31 had partial response, and 7 demonstrated pathological complete response. Forkhead box protein 3 was significantly higher in the response group than in the no response group (no response = 2.6, partial response = 7.0, complete response = 9.7, p = 0.020). Brachyury expression was inversely associated with response to neoadjuvant chemotherapy, but the difference was not statistically significant ( p = 0.62). We also observed a significant association between forkhead box protein 3 ( p = 0.001) and the Neo-Bioscore, while only a marginal difference was observed with CD8+ expression ( p = 0.074). This study demonstrated that forkhead box protein 3 expression has value as the only independent marker that predicts a good response to neoadjuvant chemotherapy and that it is related with a good prognosis according to the Neo-Bioscore. Brachyury was significantly associated with estrogen receptor positive and human epidermal growth factor receptor 2 negative status; further study would be needed to clarify how it affects treatment prognosis.

Breast Cancer Vaccines: New Insights

Breast cancer (BC) is a persistent global challenge for its high frequency in women (although it seldom occurs in men), due to the large diffusion of risk factors and gene mutations, and for its peculiar biology and microenvironment. To date, BC can benefit from different therapeutic strategies involving surgery, ablation, chemotherapy, radiotherapy, and more specific approaches such as hormone therapy and the administration of various substances impairing cancer growth, aggressivity, and recurrence with different modalities. Despite these relatively wide chances, also used in combinatory protocols, relevant mortality and relapse rates, often associated with resistant phenotypes, stress the need for a personalized-medicine based on prompting the patient's immune system (IS) against cancer cells. BC immunogenicity was latterly proven, so the whole immunotherapy field for BC is still at a very early stage. This immunotherapeutic approach exploits both the high specificity of adaptive immune response and the immunological memory. This review is focused on some of the majorly relevant BC vaccines available (NeuVax, AVX901, and INO-1400), providing a description of the more promising clinical trials. The efficacy of cancer vaccines highly depends on the patient's IS, and a wide optimization is needed in terms of targets' selection, drug design and combinations, dose finding, protocol structuring, and patients' recruitment; moreover, new standards are being discussed for the outcome evaluation. However, early-phases excellent results suggest that the manipulation of the IS via specific vaccines is a highly attractive approach for BC.

Pharmacological and immunological targeting of tumor mesenchymalization

Controlling the spread of carcinoma cells to distant organs is the foremost challenge in cancer treatment, as metastatic disease is generally resistant to therapy and is ultimately incurable for the majority of patients. The plasticity of tumor cell phenotype, in which the behaviors and functions of individual tumor cells differ markedly depending upon intrinsic and extrinsic factors, is now known to be a central mechanism in cancer progression. Our expanding knowledge of epithelial and mesenchymal phenotypic states in tumor cells, and the dynamic nature of the transitions between these phenotypes has created new opportunities to intervene to better control the behavior of tumor cells. There are now a variety of innovative pharmacological approaches to preferentially target tumor cells that have acquired mesenchymal features, including cytotoxic agents that directly kill these cells, and inhibitors that block or revert the process of mesenchymalization. Furthermore, novel immunological strategies have been developed to engage the immune system in seeking out and destroying mesenchymalized tumor cells. This review highlights the relevance of phenotypic plasticity in tumor biology, and discusses recently developed pharmacological and immunological means of targeting this phenomenon.