HER2-specific T lymphocytes kill both trastuzumab-resistant and trastuzumab-sensitive breast cell lines in vitro

Immunotherapy for HER2-Positive Breast Cancer: Clinical Evidence and Future Perspectives

Breast cancer is the most common malignancy among women worldwide, and HER2-positive breast cancer accounts for approximately 15% of all breast cancer diagnoses. The advent of HER2-targeting therapies has dramatically improved the survival of these patients, significantly reducing their risk of recurrence and death. However, as a significant proportion of patients ultimately develop resistance to these therapies, it is extremely important to identify new treatments to further improve their clinical outcomes. Immunotherapy has revolutionized the treatment and history of several cancer types, and it has already been approved as a standard of care for patients with triple-negative breast cancer. Based on a strong preclinical rationale, immunotherapy in HER2-positive breast cancer represents an intriguing field that is currently under clinical investigation. There is a close interplay between HER2-targeting therapies (both approved and under investigation) and the immune system, and several new immunotherapeutic strategies, including immune checkpoint inhibitors, CAR-T cells and therapeutic vaccines, are being studied in this disease. In this narrative review, we discuss the clinical evidence and the future perspectives of immunotherapy for patients with HER2-positive breast cancer.

Preparation of Diphtheria and Pseudomonas Exotoxin A Immunotoxins and Evaluation of Their Cytotoxicity Effect on SK-BR-3, BT-474, and MDA-MB-231 Breast Cancer Cell Lines

Immunotoxin targeted therapy is a promising way of cancer therapy that is made from a toxin attached to an antibody which target a specific protein presented on cancer cells. In this study, we introduce immunotoxins comprising of truncated pseudomonas exotoxin A (PEA) and diphtheria toxin (DT) conjugated to trastuzumab. The effectiveness of 20 and 30 μg/ml immunotoxins and trastuzumab were studied on SK-BR-3 and BT-474 HER2/neu positive breast cancer cell lines by a cell death assay test. The produced immunotoxins have the potential to reduce the therapeutic dose of the trastuzumab and in the same time achieve higher efficiency.

Extensive exploration of T cell heterogeneity in cancers by single cell sequencing

Human T cells are a highly heterogeneous population and can recognize a wide variety of antigens by their T cell receptors (TCRs). Tumor cells display a large repertoire of antigens that serve as potential targets for recognition, thus making T cells in the tumor micro-environment more complicated. Making a connection between TCRs and the transcriptional information of individual T cells will be interesting for investigating clonal expansion within T cell populations under pathologic conditions. Advances in single cell RNA-sequencing (scRNA-seq) have allowed for comprehensive analysis of T cells. In this review, we briefly describe the research progress on tumor micro-environment T cells using single cell RNA sequencing, and then discuss how scRNA-seq can be used to resolve immune system heterogeneity in health and disease. Finally, we point out future directions in this field and potential for immunotherapy.

Promising clinical application of ctDNA in evaluating immunotherapy efficacy

An increasing number of promising immunotherapies and related clinical trials have led to several major breakthroughs in multiple cancers, but a reliable and precise biomarker for evaluating efficacy and prognosis has not yet been established. As a typical representation of a liquid biopsy, circulating cell-free DNA (ctDNA) possesses the functions and advantages of tissue biopsy but its distinct advantages of convenience, real-time nature, non-invasiveness and homogeneity make it superior to tissue biopsy. Indeed, compared with routine imaging and tumor markers, ctDNA offers an earlier indication and provides more precise information. ctDNA is reportedly able to identify immunotherapy responders, evaluate efficacy and survival time, screen immune checkpoint inhibitor resistance and pseudo-progress and predict tumor recurrence and metastasis. Thus, ctDNA can act as an "Eagle Eye" by comprehensively monitoring both macro- and micro-changes in the immunotherapy process. Although ctDNA has become a research topic of interest, its limitations cannot be ignored, and improvements in its sensitivity and standardization are urgently needed. This review reveals the advantages and limitations of ctDNA as a precise biomarker and supports the feasibility of using ctDNA detection for common monitoring during immunotherapy.

Regulation of dual specificity phosphatases in breast cancer during initial treatment with Herceptin: a Boolean model analysis

Background

25% of breast cancer patients suffer from aggressive HER2-positive tumours that are characterised by overexpression of the HER2 protein or by its increased tyrosine kinase activity. Herceptin is a major drug used to treat HER2 positive breast cancer. Understanding the molecular events that occur when breast cancer cells are exposed to Herceptin is therefore of significant importance. Dual specificity phosphatases (DUSPs) are central regulators of cell signalling that function downstream of HER2, but their role in the cellular response to Herceptin is mostly unknown. This study aims to model the initial effects of Herceptin exposure on DUSPs in HER2-positive breast cancer cells using Boolean modelling.

Results

We experimentally measured expression time courses of 21 different DUSPs between 0 and 24 h following Herceptin treatment of human MDA-MB-453 HER2-positive breast cancer cells. We clustered these time courses into patterns of similar dynamics over time. In parallel, we built a series of Boolean models representing the known regulatory mechanisms of DUSPs and then demonstrated that the dynamics predicted by the models is in agreement with the experimental data. Furthermore, we used the models to predict regulatory mechanisms of DUSPs, where these mechanisms were partially known.

Conclusions

Boolean modelling is a powerful technique to investigate and understand signalling pathways. We obtained an understanding of different regulatory pathways in breast cancer and new insights on how these signalling pathways are activated. This method can be generalized to other drugs and longer time courses to better understand how resistance to drugs develops in cancer cells over time.

Electronic supplementary material

The online version of this article (10.1186/s12918-018-0534-5) contains supplementary material, which is available to authorized users.

ErbB2 signaling epigenetically suppresses microRNA-205 transcription via Ras/Raf/MEK/ERK pathway in breast cancer

We previously reported that microRNA-205 (miR-205) is downregulated by overexpression of the receptor tyrosine kinase ErbB2 and that ectopic transfection of miR-205 precursor decreases ErbB2 tumorigenicity in soft agar. In this study, we further analyzed the regulatory mechanisms linking ErbB2 overexpression and miR-205 downregulation. In ErbB2-overexpressing breast epithelial cells, miR-205 expression was significantly increased by treatment with MEK inhibitor U0126 or PD98059, Raf-1 inhibitor ZM-336372, and ERK inhibitor SCH772984, but PI3K inhibitor LY294002 and p38 MAPK inhibitor SB203580 had no effect. We established breast epithelial cells overexpressing RafCAAX, a constitutively active form of Raf-1, and showed that overexpression of RafCAAX dramatically reduced miR-205 expression. In RafCAAX-overexpressing cells, miR-205 expression was also significantly increased by SCH772984. Moreover, miR-205 expression was significantly increased by treatment with DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine and expression of several DNMT family members was increased in both ErbB2- and RafCAAX-overexpressing cells. DNA methylation analysis by bisulfite sequencing revealed that the putative miR-205 promoters were predominantly hypermethylated in both ErbB2- and RafCAAX-overexpressing cells. Reporter activity of the putative miR-205 promoters was reduced in both ErbB2-overexpressing and RafCAAX-overexpressing cells. Together, these findings indicate that ErbB2 signaling epigenetically suppresses miR-205 transcription via the Ras/Raf/MEK/ERK pathway.

A novel multi-epitope vaccine from MMSA-1 and DKK1 for multiple myeloma immunotherapy

The identification of novel tumour-associated antigens is urgently needed to improve the efficacy of immunotherapy for multiple myeloma (MM). In this study, we identified a membrane protein MMSA-1 (multiple myeloma special antigen-1) that was specifically expressed in MM and exhibited significantly positive correlation with MM. We then identified HLA-A*0201-restricted MMSA-1 epitopes and tested their cytotoxic T lymphocyte (CTL) response. The MMSA-1 epitope SLSLLTIYV vaccine was shown to induce an obvious CTL response in vitro. To improve the immunotherapy, we constructed a multi-epitope peptide vaccine by combining epitopes derived from MMSA-1 and Dickkopf-1 (DKK1). The effector T cells induced by multi-epitope peptide vaccine-loaded dendritic cells lysed U266 cells more effectively than MMSA-1/DKK1 single-epitope vaccine. In myeloma-bearing severe combined immunodeficient mice, the multi-epitope vaccine improved the survival rate significantly compared with single-epitope vaccine. Consistently, multi-epitope vaccine decreased the tumour volume greatly and alleviated bone destruction. The frequencies of CD4⁺ and CD8⁺ T cells was significantly increased in mouse blood induced by the multi-epitope vaccine, indicating that it inhibits myeloma growth by changing T cell subsets and alleviating immune paralysis. This study identified a novel peptide from MMSA-1 and the multi-epitope vaccine will be used to establish appropriate individualized therapy for MM.

Differential peripheral blood gene expression profile based on Her2 expression on primary tumors of breast cancer patients

Breast cancer prognosis and treatment is highly dependent on the molecular features of the primary tumors. These tumors release specific molecules into the environment that trigger characteristic responses into the circulatory cells. In this study we investigated the expression pattern of 84 genes known to be involved in breast cancer signaling in the peripheral blood of breast cancer patients with ER-, PR- primary tumors. The patients were grouped according to Her2 expression on the primary tumors in Her2+ and Her2- cohorts. Transcriptional analysis revealed 15 genes to be differentially expressed between the two groups highlighting that Her2 signaling in primary tumors could be associated with specific blood gene expression. We found CCNA1 to be up-regulated, while ERBB2, RASSF1, CDH1, MKI67, GATA3, GLI1, SFN, PTGS2, JUN, NOTCH1, CTNNB1, KRT8, SRC, and HIC1 genes were down-regulated in the blood of triple negative breast cancer patients compared to Her2+ cohort. IPA network analysis predicts that the identified genes are interconnected and regulate each other. These genes code for cell cycle regulators, cell adhesion molecules, transcription factors or signal transducers that modulate immune signaling, several genes being also associated with cancer progression and treatment response. These results indicate an altered immune signaling in the peripheral blood of triple negative breast cancer patients. The involvement of the immune system is necessary in favorable treatment response, therefore these results could explain the low response rates observed for triple negative breast cancer patients.