erbB-2 is a potent oncogene when overexpressed in NIH/3T3 cells

Can neoadjuvant systemic therapy provide additional benefits for T1 HER2+ breast cancer patients: a subgroup analysis based on different high-risk signatures

INTRODUCTION

Neoadjuvant systemic therapy (NAST) is vital in the management of HER2-positive (HER2+) breast cancer. Nevertheless, the indications for NAST in tumors <2 cm remain controversial.

METHOD

A total of 7961 patients were screened from the Surveillance, Epidemiology, and End Result database. Independent prognostic factors were identified using multivariate Cox analysis. Subgroup analyses and Kaplan-Meier analyses were used to simulate whether NAST would provide a survival benefit with different high-risk characteristics. Nomograms were constructed, and an internal validation cohort was employed.

RESULTS

Of the 7961 included patients, 1137 (14.3%) underwent NAST. In the total population, NAST was associated with poorer overall survival (OS) and breast cancer-specific survival (BCSS) (OS: P = 0.00093; BCSS: P  <  0.0001). Multivariate Cox analysis confirmed that NAST markedly affected the prognosis of enrolled patients. Besides, a direct association between T, N, age, subtype, and prognosis was observed. Subgroup analyses yielded in these three subgroups, T1c, hormone receptor-negative, and 61-69 years of age, NAST and AST had comparable OS, while NAST possessed worse BCSS. Notably, even in the N3, we still did not observe any additional benefit of NAST. The calculated C-index of 0.72 and 0.73 confirmed the predictability of the nomograms. The AUCs exhibit consistency in the training and validation cohorts.

CONCLUSION

Our findings suggest that NAST does not provide additional benefit to patients with T1 HER2+ breast cancer, even in the presence of lymph node metastasis, T1c, or hormone receptor negativity. This study facilitates the implementation of individualized management strategies.

New clinical trial design in precision medicine: discovery, development and direction

In the era of precision medicine, it has been increasingly recognized that individuals with a certain disease are complex and different from each other. Due to the underestimation of the significant heterogeneity across participants in traditional "one-size-fits-all" trials, patient-centered trials that could provide optimal therapy customization to individuals with specific biomarkers were developed including the basket, umbrella, and platform trial designs under the master protocol framework. In recent years, the successive FDA approval of indications based on biomarker-guided master protocol designs has demonstrated that these new clinical trials are ushering in tremendous opportunities. Despite the rapid increase in the number of basket, umbrella, and platform trials, the current clinical and research understanding of these new trial designs, as compared with traditional trial designs, remains limited. The majority of the research focuses on methodologies, and there is a lack of in-depth insight concerning the underlying biological logic of these new clinical trial designs. Therefore, we provide this comprehensive review of the discovery and development of basket, umbrella, and platform trials and their underlying logic from the perspective of precision medicine. Meanwhile, we discuss future directions on the potential development of these new clinical design in view of the "Precision Pro", "Dynamic Precision", and "Intelligent Precision". This review would assist trial-related researchers to enhance the innovation and feasibility of clinical trial designs by expounding the underlying logic, which be essential to accelerate the progression of precision medicine.

Management of patients with advanced-stage HER2-positive breast cancer: current evidence and future perspectives

Amplification and/or overexpression of ERBB2, the gene encoding HER2, can be found in 15-20% of invasive breast cancers and is associated with an aggressive phenotype and poor clinical outcomes. Relentless research efforts in molecular biology and drug development have led to the implementation of several HER2-targeted therapies, including monoclonal antibodies, tyrosine-kinase inhibitors and antibody-drug conjugates, constituting one of the best examples of bench-to-bedside translation in oncology. Each individual drug class has improved patient outcomes and, importantly, the combinatorial and sequential use of different HER2-targeted therapies has increased cure rates in the early stage disease setting and substantially prolonged survival for patients with advanced-stage disease. In this Review, we describe key steps in the development of the modern paradigm for the treatment of HER2-positive advanced-stage breast cancer, including selecting and sequencing new-generation HER2-targeted therapies, and summarize efficacy and safety outcomes from pivotal studies. We then outline the factors that are currently known to be related to resistance to HER2-targeted therapies, such as HER2 intratumoural heterogeneity, activation of alternative signalling pathways and immune escape mechanisms, as well as potential strategies that might be used in the future to overcome this resistance and further improve patient outcomes.

Clinicopathological features and prognosis of patients with HER2-low breast cancer

BACKGROUND

Low human epidermal growth factor receptor 2 (HER2) expression is an emerging concept in breast cancer that is defined as immunohistochemistry (IHC) 1 + or IHC 2 + and negative in situ hybridization (ISH) but has been poorly investigated. The aim of our study was to determine the frequency of low HER2 expression among HER2-negative breast cancers and compare the clinicopathological features and prognosis of HER2-low patients with those of HER2-zero patients.

METHODS

We collected the data of 684 patients with primary HER2-negative breast cancer who underwent surgery between January 2012 and September 2021 from our self-built database. Clinicopathological features, recurrence-free interval (RFI) and breast cancer-specific survival (BCSS) were compared between HER2-low and HER2-zero (IHC 0) patients.

RESULTS

Among the 684 patients, 512 (74.9%) patients had low HER2 expression, and 172 (25.1%) patients had zero HER2 expression. The average age was 57.7 ± 12.6 years, 472 (69.0%) patients were aged < 65 years, and 212 (31.0%) patients were aged ≥ 65 years. Compared to HER2-zero tumors, HER2-low tumors had a higher proportion of hormone receptor (HR)-positive cases (89.6% vs. 75.6%, P < 0.001) and a lower rate of histological grade III cases (29.4% vs. 38.8%, P < 0.001). Kaplan-Meier analysis showed that low HER2 expression was associated with prolonged RFI in breast cancer patients, especially in HR + breast cancer patients (P = 0.028) and < 65-year-old breast cancer patients (P = 0.000). Multivariate Cox regression analysis showed that low HER2 expression was a low-risk factor for RFI (HR: 0.531, 95% CI: 0.292-0.967, P = 0.038) but had no influence on BCSS (P = 0.272).

CONCLUSIONS

HER2-low tumors had a higher proportion of HR positivity and a lower rate of histological grade III than HER2-zero tumors. Low HER2 expression seemed to be a protective factor for RFI, especially in patients with HR + and those younger than 65 years.

Peptides Targeting HER2-Positive Breast Cancer Cells and Applications in Tumor Imaging and Delivery of Chemotherapeutics

Breast cancer represents the most common cancer type and one of the major leading causes of death in the female worldwide population. Overexpression of HER2, a transmembrane glycoprotein related to the epidermal growth factor receptor, results in a biologically and clinically aggressive breast cancer subtype. It is also the primary driver for tumor detection and progression and, in addition to being an important prognostic factor in women diagnosed with breast cancer, HER2 is a widely known therapeutic target for drug development. The aim of this review is to provide an updated overview of the main approaches for the diagnosis and treatment of HER2-positive breast cancer proposed in the literature over the past decade. We focused on the different targeting strategies involving antibodies and peptides that have been explored with their relative outcomes and current limitations that need to be improved. The review also encompasses a discussion on targeted peptides acting as probes for molecular imaging. By using different types of HER2-targeting strategies, nanotechnology promises to overcome some of the current clinical challenges by developing novel HER2-guided nanosystems suitable as powerful tools in breast cancer imaging, targeting, and therapy.

Co-crystallisation and humanisation of an anti-HER2 single-domain antibody as a theranostic tool

Human epidermal growth factor receptor-2 (HER2) is a well-recognised biomarker associated with 25% of breast cancers. In most cases, early detection and/or treatment correlates with an increased chance of survival. This study, has identified and characterised a highly specific anti-HER2 single-domain antibody (sdAb), NM-02, as a potential theranostic tool. Complete structural description by X-ray crystallography has revealed a non-overlapping epitope with current anti-HER2 antibodies. To reduce the immunogenicity risk, NM-02 underwent a humanisation process and retained wild type-like binding properties. To further de-risk the progression towards chemistry, manufacturing and control (CMC) we performed full developability profiling revealing favourable thermal and physical biochemical 'drug-like' properties. Finally, the application of the lead humanised NM-02 candidate (variant K) for HER2-specific imaging purposes was demonstrated using breast cancer HER2+/BT474 xenograft mice.

Ultrafast prediction of somatic structural variations by filtering out reads matched to pan-genome k-mer sets

Variant callers typically produce massive numbers of false positives for structural variations, such as cancer-relevant copy-number alterations and fusion genes resulting from genome rearrangements. Here we describe an ultrafast and accurate detector of somatic structural variations that reduces read-mapping costs by filtering out reads matched to pan-genome k-mer sets. The detector, which we named ETCHING (for efficient detection of chromosomal rearrangements and fusion genes), reduces the number of false positives by leveraging machine-learning classifiers trained with six breakend-related features (clipped-read count, split-reads count, supporting paired-end read count, average mapping quality, depth difference and total length of clipped bases). When benchmarked against six callers on reference cell-free DNA, validated biomarkers of structural variants, matched tumour and normal whole genomes, and tumour-only targeted sequencing datasets, ETCHING was 11-fold faster than the second-fastest structural-variant caller at comparable performance and memory use. The speed and accuracy of ETCHING may aid large-scale genome projects and facilitate practical implementations in precision medicine.

Dual kinase inhibitor for EGFR mutants and ErbB2 limit breast cancer

Mutations in the epidermal growth factor receptor (EGFR) have been found in more than 10% of non-small cell lung cancer (NSCLC) patients in North America. The vast majority of these differences are L858R point mutations in Exon 21. Currently, monoclonal antibodies directed against the extracellular domain of EGFR or small molecule/tyrosine kinase inhibitors (TKI) are the stalwarts of NSCLC therapy. Resistance, however, gradually develops because of the T790 mutation towards first and second generation TKIs. The third generation TKI AZD9291 (Osimertinib) has a high affinity for both activating and the acquired resistant mutation (T790 M) in EGFR, with a low affinity towards wild-type EGFR. Recent research, however, suggests that the EGFR (C797S) mutation in the tyrosine kinase domain is a likely cause of resistance to AZD9291. Another significant transformation mechanism associated with this resistance is erbB2 amplification. Our laboratory has developed a small kinase inhibitor, ER121 (MW: ∼500), that inhibits the erbB2/HER2 tyrosine kinases in addition to the EGFR C797S mutations. We have identified a TKI, ER121 targeting the mutant EGFR(T790 M). Using in vitro and in vivo models, examined the efficacy of ER121 on mutant EGFR cell lines. This has enabled us to establish that ER121 is well tolerated when administered orally and produces significant inhibitory activity against human cancers generated by mutant EGFR and amplified ErbB2.

Clinical management of drug-induced cardiotoxicity in patients with HER-2+ breast cancer: current recommendations and future outlook

INTRODUCTION

Human epidermal growth factor receptor two (HER2) target therapies have drastically revolutionised the treatment of HER2-positive breast cancer. Starting with trastuzumab, early phase III trials have already highlighted its significant cardiotoxicity, which is also present, albeit to a lesser extent, in the new generation drugs. Also given the growing population of patients with cardiovascular diseases, it is vital to set up proper long-term follow-up to prevent morbidity related to the development of cardiotoxicity.

AREAS COVERED

This review discusses the mechanisms of action underlying the cardiotoxicity of HER2 targeted therapies and the main clinical evidence on the toxicity of these drugs. In addition, the patterns of patient assessment prior to the initiation of therapy with HER2 targeted therapies are discussed, as well as the main evidence concerning the follow-up and management of cardiotoxicity.

EXPERT OPINION

the mechanisms of cardiotoxicity of new HER2 drugs need further study and, likewise, methods to prevent, monitor and identify HER-2-induced cardiotoxicity need to be implemented. Although some studies highlight the validity of cardiac biomarkers as predictive factors for cardiotoxicity, their actual usefulness and timing is still debated. Further studies are needed to assess the effectiveness of possible pharmacological primary prevention.

Breastfeeding reduces the risk of breast cancer: A call for action in high-income countries with low rates of breastfeeding

Women in the UK have a 15% lifetime risk of developing breast cancer. Like other high-income countries, women in the UK are having children later in life which increases their risk. The risk of breast cancer is reduced by 4.3% for every 12 months of breastfeeding, this is in addition to the 7.0% decrease in risk observed for each birth. Breastfeeding reduces the risk of Triple-Negative Breast Cancer (20%) and in carriers of BRCA1 mutations (22-55%). The mechanisms of reduced risk as a result of pregnancy are related to changes in RNA processing and cellular differentiation. The UK has a low rate of breastfeeding (81%) and this is contrasted to countries with higher (Sweden, Australia) and lower rates (Ireland). The low UK rate is in part due to a lack of experience in the population, todays grandmothers have less experience with breastfeeding (62%) than their daughters. An estimated 4.7% of breast cancer cases in the UK are caused by not breastfeeding. The UK only has 43% of maternity services with full Baby-Friendly accreditation which promotes compliance with the WHO 'Ten Steps to Successful Breast Feeding'. Legislation in the UK and Europe is far short of the WHO Guidance on restricting the advertising of formula milk. Expansion of the Baby-Friendly Hospital Initiative, stricter laws on the advertising of formula milk and legislation to support nursing mothers in the workplace have the potential to increase breastfeeding in the UK. Women with a family history of breast cancer should particularly be supported to breastfeed as a way of reducing their risk.

An anti-EGFR antibody-drug conjugate overcomes resistance to HER2-targeted drugs

Trastuzumab-emtansine (T-DM1) is an antibody-drug conjugate (ADC) that was approved in 2013 to treat HER2+ breast cancer. Despite its efficacy in the clinic, some patients exhibit intrinsic or acquired resistance to such ADC. To characterize mechanisms of resistance to T-DM1, we isolated several HER2+ resistant clones derived from the HCC1954 HER2+ cell line. The isolated clones were different as per their transcriptomic profiles. However, all the T-DM1-resistant clones showed decreased HER2 levels. Yet, the clones were still oncogenically dependent on HER2, as indicated by knock down experiments. The decrease in HER2 expression caused acquired resistance to T-DM1 and to other anti-HER2 therapies. Antibody array analyses showed that the epidermal growth factor receptor (EGFR) was expressed in these T-DM1-resistant HCC1954 clones. Indeed, therapies targeting EGFR, particularly cetuximab-DM1, demonstrated a strong anti-proliferative action on cells with acquired resistance to T-DM1 and HER2 loss. The expression of EGFR in cells resistant to T-DM1 offers the possibility of using therapies directed to this receptor to combat resistance to anti-HER2 drugs and loss of HER2 overexpression.

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.

HER3 in cancer: from the bench to the bedside

The HER3 protein, that belongs to the ErbB/HER receptor tyrosine kinase (RTK) family, is expressed in several types of tumors. That fact, together with the role of HER3 in promoting cell proliferation, implicate that targeting HER3 may have therapeutic relevance. Furthermore, expression and activation of HER3 has been linked to resistance to drugs that target other HER receptors such as agents that act on EGFR or HER2. In addition, HER3 has been associated to resistance to some chemotherapeutic drugs. Because of those circumstances, efforts to develop and test agents targeting HER3 have been carried out. Two types of agents targeting HER3 have been developed. The most abundant are antibodies or engineered antibody derivatives that specifically recognize the extracellular region of HER3. In addition, the use of aptamers specifically interacting with HER3, vaccines or HER3-targeting siRNAs have also been developed. Here we discuss the state of the art of the preclinical and clinical development of drugs aimed at targeting HER3 with therapeutic purposes.

ERCC1 is a potential biomarker for predicting prognosis, immunotherapy, chemotherapy efficacy, and expression validation in HER2 over-expressing breast cancer

Objective

To investigate the relationship between Excision repair cross-complementation 1 (ERCC1) expression, clinicopathological features, and breast cancer prognosis in patients treated with trastuzumab. Further, we aim to explore the immune status of ERCC1 in breast cancer.

Methods

The data were retrieved from publicly available databases like the Cancer Genome Atlas, Therapeutically Applicable Research to Generate Effective Treatments, and the Genotype-Tissue Expression. The data was used to perform differential expression analyses between tumor and normal tissues in pan-cancers, immune-related analysis, homologous recombination deficiency (HRD), tumor mutation burden, and microsatellite instability. A total of 210 patients with HER2 over-expressing breast cancer from the Fourth Hospital of Hebei Medical University between January 2013 to December 2015 were enrolled in the study. Ten adjacent normal tissues were used to study the expression pattern of ERCC1 in normal tissues. Immunohistochemistry was performed to study ERCC1 expression and immune cell infiltration in different status of ERCC1 expression. Further, the correlation between ERCC1 expression, immune cell infiltration clinicopathological features, and the prognosis of patients with breast cancer was analyzed.

Results

The immune analysis revealed a significant correlation between CD8+ T cell, CD4+ T cell, T helper cell, macrophages, mast cells, and ERCC1 expression. Spearman analysis show that ERCC1 expression is related to macrophages and T cells. A close correlation was observed between increased ERCC1 expression and high tumor immune dysfunction and exclusion (TIDE) score as well as HRD. The results revealed a significant correlation among ERCC1, chemotherapy and estrogen receptor (ER; P < 0.05) expression. Univariate survival analysis revealed a significant correlation (P < 0.05) between that ERCC1 and ER expression, blood vessel invasion, and disease-free survival (DFS). ERCC1 and ER expression, tumor size, blood vessel invasion, pathological type, and lymph node metastases significantly correlated (P < 0.05) with overall survival in patients. Multivariate regression analysis revealed that ERCC1 expression and chemotherapy were independent factors that influence DFS. ERCC1 expression and vascular tumor thrombus were independent influencing factors that influence OS.

Conclusion

A correlation was observed between high ERCC1 expression and poor patient prognosis. High ERCC1 expression also influences the efficacy of immunotherapy and chemotherapy.

Detection of DNA copy number alterations by matrix-assisted laser desorption/ionization time-of-flight mass spectrometric analysis of single nucleotide polymorphisms

OBJECTIVES

Copy number alterations (CNAs) are frequently found in malignant tissues. Different approaches have been used for CNA detection. However, it is not easy to detect a large panel of CNA targets in heterogenous tumors.

METHODS

We have developed a CNAs detection approach through quantitatively analyzed allelic imbalance by allelotyping single nucleotide polymorphisms (SNPs) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Furthermore, the copy number changes were quantified by real-competitive PCR (rcPCR) to distinguish loss of heterozygosity (LOH) and genomic amplification. The approach was used to validate the CNA regions detected by next generation sequencing (NGS) in early-stage lung carcinoma.

RESULTS

CNAs were detected in heterogeneous DNA samples where tumor DNA is present at only 10% through the SNP based allelotyping. In addition, two different types of CNAs (loss of heterozygosity and chromosome amplification) were able to be distinguished quantitatively by rcPCR. Validation on a total of 41 SNPs from the selected CNA regions showed that copy number changes did occur, and the tissues from early-stage lung carcinoma were distinguished from normal.

CONCLUSIONS

CNA detection by MALDI-TOF MS can be used for validating potentially interesting genomic regions identified from next generation sequencing, and for detecting CNAs in tumor tissues consisting of a mixture of neoplastic and normal cells.

Trastuzumab Deruxtecan, Antibody-Drug Conjugate Targeting HER2, Is Effective in Pediatric Malignancies: A Report by the Pediatric Preclinical Testing Consortium

HER2 is expressed in many pediatric solid tumors and is a target for innovative immune therapies including CAR-T cells and antibody-drug conjugates (ADC). We evaluated the preclinical efficacy of trastuzumab deruxtecan (T-DXd, DS-8201a), a humanized monoclonal HER2-targeting antibody conjugated to a topoisomerase 1 inhibitor, DXd, in patient- and cell line-derived xenograft (PDX/CDX) models. HER2 mRNA expression was determined using RNA-seq and protein expression via IHC across multiple pediatric tumor PDX models. Osteosarcoma (OS), malignant rhabdoid tumor (MRT), and Wilms tumor (WT) models with varying HER2 expression were tested using 10 mice per group. Additional histologies such as Ewing sarcoma (EWS), rhabdomyosarcoma (RMS), neuroblastoma (NB), and brain tumors were evaluated using single mouse testing (SMT) experiments. T-DXd or vehicle control was administered intravenously to mice harboring established flank tumors at a dose of 5 mg/kg on day 1. Event-free survival (EFS) and objective response were compared between treatment and control groups. HER2 mRNA expression was observed across histologies, with the highest expression in WT (median = 22 FPKM), followed by MRT, OS, and EWS. The relationship between HER2 protein and mRNA expression was inconsistent. T-DXd significantly prolonged EFS in 6/7 OS, 2/2 MRT, and 3/3 WT PDX models. Complete response (CR) or maintained CR (MCR) were observed for 4/5 WT and MRT models, whereas stable disease was the best response among OS models. SMT experiments also demonstrated activity across multiple solid tumors. Clinical trials assessing the efficacy of a HER2-directed ADC in pediatric patients with HER2-expressing tumors should be considered.

The efficacy of tucatinib-based therapeutic approaches for HER2-positive breast cancer

Overexpression of human epidermal growth factor receptor 2 (HER2) occurs in approximately 15-20% of breast cancer cases. HER2 is a member of the epidermal growth factor receptor (EGFR) family with tyrosinase kinase activity, and its overexpression is linked to poor prognosis and shorter progression-free survival (PFS) and overall survival (OS). Among various treatment options, HER2-targeting monoclonal antibodies and tyrosine kinase inhibitors (TKIs) have mostly been applied in recent decades to treat HER2-positive (HER2+) breast cancer patients. Although positive clinical outcomes were documented in both advanced disease and neoadjuvant settings, the development of resistance mechanisms to such approaches has been one of the major challenges with the continuous usage of these drugs. In addition, patients who experience disease progression after treatment with multiple HER2-targeted therapies often have limited treatment options. The Food and Drug Administration (FDA) has recently approved a new TKI (i.e., tucatinib) for use in combination with immunotherapy and/or chemotherapeutic agents for the treatment of advanced-stage/metastatic HER2+ breast cancer. This review highlights recent updates on the efficacy of tucatinib-based therapeutic approaches in experimental models as well as in the clinical settings of HER2+ breast cancer.

Neoadjuvant Trastuzumab and Pyrotinib for Locally Advanced HER2-Positive Breast Cancer (NeoATP): Primary Analysis of a Phase II Study

PURPOSE

Despite accumulating evidence on dual blockade of human epidermal growth factor receptor 2 (HER2) for locally advanced HER2-positive breast cancer, no robust evidence supports the addition of pyrotinib to trastuzumab in the neoadjuvant setting. The NeoATP trial aimed to evaluate the efficacy and safety of pyrotinib with neoadjuvant trastuzumab and chemotherapy.

METHODS

The phase II NeoATP trial included female patients with histologically confirmed stage IIA-IIIC and HER2-positive primary invasive breast cancer. Eligible patients received pyrotinib and trastuzumab with weekly paclitaxel-cisplatin neoadjuvant chemotherapy for four cycles. The primary endpoint was pathological complete response (pCR; ypT0 ypN0) rate. Key secondary endpoints included locoregional pCR (ypT0/is ypN0) rate, biomarker analysis and safety.

RESULTS

Among 53 enrolled patients (median age, 47 years; 73.58% stage III), 52 completed the study treatment and surgery. Overall, 37 patients (69.81%) achieved pCR. For women with hormone receptor negative and positive tumors, the pCR rates were 85.71% and 59.38% (P = 0.041), while the corresponding rates were 69.23% and 70.00% respectively for those with and without PIK3CA mutation (P = 0.958). The most frequently reported grade 3 to 4 adverse events were diarrhea (45.28%), leukopenia (39.62%) and neutropenia (32.08%). No deaths occurred, and no left ventricular ejection fraction <50% or >10 points drop from baseline to before surgery was reported.

CONCLUSIONS

The addition of pyrotinib to trastuzumab plus chemotherapy is an efficacious and safe regimen for patients with HER2-positive locally advanced breast cancer in the neoadjuvant setting. The randomized controlled clinical trial is warranted to validate our results.

A novel ensemble feature selection method for pixel-level segmentation of HER2 overexpression

Classifying histopathology images on a pixel-level requires sets of features able to capture the complex characteristics of the images, like the irregular cell morphology and the color heterogeneity on the tissue aspect. In this context, feature selection becomes a crucial step in the classification process such that it reduces model complexity and computational costs, avoids overfitting, and thereby it improves the model performance. In this study, we propose a new ensemble feature selection method by combining a set of base selectors, classifiers, and rank aggregation methods, aiming to determine from any initial set of handcrafted features, a smaller set of relevant color and texture pixel-level features, subsequently used for segmenting HER2 overexpression on a pixel-level, in breast cancer tissue images. We have been able to significantly reduce the set of initial features, using the proposed ensemble feature selection method. The best results are obtained using $$\chi ^2$$ χ 2 , Random Forest, and Runoff as the based selector, classifier, and aggregation method, respectively. The classification performance of the best model trained on the selected features set results in 0.939 recall, 0.866 specificity, 0.903 accuracy, 0.875 precision, and 0.906 F1-score.

The HER family as therapeutic targets in colorectal cancer

The human epidermal growth factor receptor (HER, ErbB) family has four members, epidermal growth factor receptor (EGFR), HER2, HER3, and HER4. Although distinct in ligands and functions, all of the HER family members are receptor tyrosine kinases playing important roles in the pathogenesis of cancers. In the era of precision medicine, the HER family is one of the most important and successful cancer therapeutic targets, hallmarked by the approval of anti-EGFR therapies for the treatment of colorectal cancer and non-small cell lung cancer, and anti-HER2 therapies for the treatment of breast cancer and gastric cancer. This review briefly discusses how HER family members were discovered, their functions and roles in cancer, and most importantly, the developmental history and recent updates of therapies targeting HER family members, with colorectal cancer as a focus. We also discussed the patient selection and drug resistance to anti-EGFR therapies in the treatment of colorectal cancer.

A Novel HER2-Selective Kinase Inhibitor Is Effective in HER2 Mutant and Amplified Non-Small Cell Lung Cancer

In-frame insertions in exon 20 of HER2 are the most common HER2 mutations in patients with non-small cell lung cancer (NSCLC), a disease in which approved EGFR/HER2 tyrosine kinase inhibitors (TKI) display poor efficiency and undesirable side effects due to their strong inhibition of wild-type (WT) EGFR. Here, we report a HER2-selective covalent TKI, JBJ-08-178-01, that targets multiple HER2 activating mutations, including exon 20 insertions as well as amplification. JBJ-08-178-01 displayed strong selectivity toward HER2 mutants over WT EGFR compared with other EGFR/HER2 TKIs. Determination of the crystal structure of HER2 in complex with JBJ-08-178-01 suggests that an interaction between the inhibitor and Ser783 may be responsible for HER2 selectivity. The compound showed strong antitumoral activity in HER2-mutant or amplified cancers in vitro and in vivo. Treatment with JBJ-08-178-01 also led to a reduction in total HER2 by promoting proteasomal degradation of the receptor. Taken together, the dual activity of JBJ-08-178-01 as a selective inhibitor and destabilizer of HER2 represents a combination that may lead to better efficacy and tolerance in patients with NSCLC harboring HER2 genetic alterations or amplification.

SIGNIFICANCE

This study describes unique mechanisms of action of a new mutant-selective HER2 kinase inhibitor that reduces both kinase activity and protein levels of HER2 in lung cancer.

Inhibiting ERK5 overcomes breast cancer resistance to anti-HER2 therapy by targeting the G1/S cell cycle transition

Targeting the human epidermal growth factor receptor 2 (HER2) became a landmark in the treatment of HER2-driven breast cancer. Nonetheless, the clinical efficacy of anti-HER2 therapies can be short-lived and a significant proportion of patients ultimately develop metastatic disease and die. One striking consequence of oncogenic activation of HER2 in breast cancer cells is the constitutive activation of the extracellular-regulated protein kinase 5 (ERK5) through its hyperphosphorylation. In this study, we sought to decipher the significance of this unique molecular signature in promoting therapeutic resistance to anti-HER2 agents. We found that a small-molecule inhibitor of ERK5 suppressed the phosphorylation of the retinoblastoma protein (RB) in HER2 positive breast cancer cells. As a result, ERK5 inhibition enhanced the anti-proliferative activity of single-agent anti-HER2 therapy in resistant breast cancer cell lines by causing a G1 cell cycle arrest. Moreover, ERK5 knockdown restored the anti-tumor activity of the anti-HER2 agent lapatinib in human breast cancer xenografts. Taken together, these findings support the therapeutic potential of ERK5 inhibitors to improve the clinical benefit that patients receive from targeted HER2 therapies.

Trastuzumab/Pertuzumab combination therapy stimulates anti-tumor responses through complement-dependent cytotoxicity and phagocytosis

Standard-of-care treatment for advanced HER2+ breast cancers (BC) is comprised of two HER2-specific monoclonal antibodies (mAb), Trastuzumab (T) and Pertuzumab (P) with chemotherapy. While this combination (T+P) is highly effective, its synergistic mechanism of action (MOA) is not completely known. Initial studies had demonstrated that Pertuzumab suppressed HER2 hetero-dimerization as the potential therapeutic MOA, thus the improved outcome associated with the T+P combination MOA compared to Trastuzumab alone has been widely reported as being due to Pertuzumab-mediated suppression of HER2 signaling in combination with Trastuzumab-mediated induction of anti-tumor immunity. Unraveling this MOA may be critical to extend this combination strategy to other antigens or other cancers, as well as improving this current treatment modality. Using novel murine and human versions of Pertuzumab, we found it induced both Antibody-Dependent-Cellular-Phagocytosis (ADCP) by tumor-associated macrophages and suppression of HER2 oncogenic signaling. Most significantly, we identified that only T+P combination therapy, but not when either antibody used in isolation, allows for the activation of the classical complement pathway, resulting in both direct complement-dependent cytotoxicity (CDC) as well as complement-dependent cellular phagocytosis (CDCP) of HER2+ BC cells. Notably, we show that tumor expression of C1q was positively associated with survival outcome in HER2+ BC patients, whereas expression of complement regulators CD55 and CD59 were inversely correlated, suggesting the importance of complement activity in clinical outcomes. Accordingly, inhibition of C1 activity in mice abolished the synergistic therapeutic activity of T+P therapy, whereas knockdown of CD55 and CD59 expression enhanced T+P efficacy. In summary, our study identifies classical complement activation as a significant anti-tumor MOA for T+P therapy that may be functionally enhanced to augment therapeutic efficacy in the clinic.

Afatinib alone and in combination with vinorelbine or paclitaxel, in patients with HER2-positive breast cancer who failed or progressed on prior trastuzumab and/or lapatinib (LUX-Breast 2): an open-label, multicenter, phase II trial

Purpose

Resistance to HER2 (ErbB2)-targeted therapy may be mediated by other members of the ErbB family. We investigated the efficacy and safety of the irreversible ErbB family blocker, afatinib, alone as first-line therapy in the advanced setting and in combination with vinorelbine or paclitaxel for those who progressed on afatinib monotherapy, in female patients with metastatic breast cancer who had failed or progressed on prior HER2-targeted therapy in the early disease setting.

Methods

In this phase II, single-arm, two-part study (ClinicalTrials.gov: NCT01271725), patients in part A received afatinib 40 mg/day in 21-day cycles until disease progression or intolerable adverse events (AEs). Patients with progressive disease could then receive afatinib plus weekly vinorelbine 25 mg/m² or paclitaxel 80 mg/m² until disease progression or intolerable AEs (part B). The primary endpoint was confirmed objective response rate (RECIST v1.1).

Results

Eighty-seven patients were enrolled and 74 were treated in part A (median age: 51 years [range 27–76]; 31 [42%] estrogen receptor-positive, 26 [35%] progesterone receptor-positive). Of these, 39 (53%) patients went on to receive afatinib plus vinorelbine (13 patients) or paclitaxel (26 patients) in part B. Thirteen (18%) and 12 (31%) patients achieved an objective response in parts A and B, respectively. The most common treatment-related AEs with afatinib monotherapy (any/grade ≥ 3) were diarrhea (68%/8%) and rash (49%/4%). Combination therapy was generally well tolerated, with no additive toxicity observed.

Conclusion

Afatinib treatment, alone or in combination with vinorelbine or paclitaxel, was associated with objective responses in ≥ 18% of patients with metastatic breast cancer for whom prior HER2-targeted therapy has failed. Treatment-related AEs were generally manageable, with few grade ≥ 3 AEs reported.

Trial registration

ClinicalTrials.gov, NCT01271725, registered 1 July 2011.

Allosteric Inhibition of HER2 by Moesin-Mimicking Compounds Targets HER2-Positive Cancers and Brain Metastases

Therapies targeting the tyrosine kinase receptor HER2 have significantly improved survival of patients with HER2⁺ cancer. However, both de novo and acquired resistance remain a challenge, particularly in the brain metastatic setting. Here we report that, unlike other HER tyrosine kinase receptors, HER2 possesses a binding motif in its cytosolic juxtamembrane region that allows interaction with members of the Ezrin/Radixin/Moesin (ERM) family. Under physiologic conditions, this interaction controls the localization of HER2 in ERM-enriched domains and stabilizes HER2 in a catalytically repressed state. In HER2⁺ breast cancers, low expression of Moesin correlated with increased HER2 expression. Restoring expression of ERM proteins in HER2⁺ breast cancer cells was sufficient to revert HER2 activation and inhibit HER2-dependent proliferation. A high-throughput assay recapitulating the HER2-ERM interaction allowed for screening of about 1,500 approved drugs. From this screen, we found Zuclopenthixol, an antipsychotic drug that behaved as a Moesin-mimicking compound, because it directly binds the juxtamembrane region of HER2 and specifically inhibits HER2 activation in HER2⁺ cancers, as well as activation of oncogenic mutated and truncated forms of HER2. Zuclopenthixol efficiently inhibited HER2⁺ breast tumor progression in vitro and in vivo and, more importantly, showed significant activity on HER2⁺ brain tumor progression. Collectively, these data reveal a novel class of allosteric HER2 inhibitors, increasing the number of approaches to consider for intervention on HER2⁺ breast cancers and brain metastases. SIGNIFICANCE: This study demonstrates the functional role of Moesin in maintaining HER2 in a catalytically repressed state and provides novel therapeutic approaches targeting HER2⁺ breast cancers and brain metastasis using Moesin-mimicking compounds.

Neu Perspectives, Therapies, and Challenges for Metastatic HER2-Positive Breast Cancer

Even though gene amplification or protein overexpression occurs in approximately one-fifth of all breast cancers, the discovery of HER2 has, nevertheless, had profound implications for the disease. Indeed, the characterization of the receptor resulted in a number of significant advances. Structurally, unique features provided avenues for the development of numerous compounds with target-specificity; molecularly, biological constructs revealed a highly complex, internal signal transduction pathway with regulatory effects on tumor proliferation, survival, and perhaps, even resistance; and clinically, disease outcomes manifested its predictive and prognostic value. Yet despite the receptor’s utility, the beneficial effects are diminished by tumor recurrence after neo- or adjuvant therapy as well as losses resulting from the inability to cure patients with metastatic disease. What these observations suggest is that while tumor response may be partially linked to uncoupling cell surface message reception and nuclear gene expression, as well as recruitment of the innate immune system, disease progression and/or resistance may involve a reprogrammable signaling mainframe that elicits alternative growth and survival signals. This review attempts to meld current perceptions related to HER2-positive metastatic breast cancer with particular attention to current biological insights and therapeutic challenges.

HER2-directed antibodies, affibodies and nanobodies as drug-delivery vehicles in breast cancer with a specific focus on radioimmunotherapy and radioimmunoimaging

PURPOSE

The aim of the present paper is to review the role of HER2 antibodies, affibodies and nanobodies as vehicles for imaging and therapy approaches in breast cancer, including a detailed look at recent clinical data from antibody drug conjugates and nanobodies as well as affibodies that are currently under development.

RESULTS

Clinical and preclinical studies have shown that the use of monoclonal antibodies in molecular imaging is impaired by slow blood clearance, associated with slow and low tumor uptake and with limited tumor penetration potential. Antibody fragments, such as nanobodies, on the other hand, can be radiolabelled with short-lived radioisotopes and provide high-contrast images within a few hours after injection, allowing early diagnosis and reduced radiation exposure of patients. Even in therapy, the small radioactively labeled nanobodies prove to be superior to radioactively labeled monoclonal antibodies due to their higher specificity and their ability to penetrate the tumor.

CONCLUSION

While monoclonal antibodies are well established drug delivery vehicles, the current literature on molecular imaging supports the notion that antibody fragments, such as affibodies or nanobodies, might be superior in this approach.

The anti-B7-H4 checkpoint synergizes trastuzumab treatment to promote phagocytosis and eradicate breast cancer

Trastuzumab is a humanized mAb used to treat HER2-overexpressing breast cancer; however its mechanisms remain to be fully elucidated. Previous studies suggest a role for immunity in mediating trastuzumab-specific antitumor effects. This study evaluated the role(s) of trastuzumab and other antibodies on macrophage activation and Ab-dependent cell-mediated phagocytosis (ADCP) of HER2⁺ breast cancer cells in vitro and in vivo. We employed orthotopic implantation of HER2⁺ murine breast cancer (BC) cells in immunocompetent mouse models, a human HER2⁺ BC xenograft in an immune humanized mouse model, and human PDXs involving adoptive transfer of autologous macrophages to simulate an endogenous mammary tumor-immune microenvironment. Our study demonstrated that trastuzumab greatly and consistently increased macrophage frequency and tumor-cell phagocytosis, and that concurrent knockdown of B7-H4 by a neutralizing antibody increased immune cell infiltration and promoted an antitumor phenotype. Furthermore, neoadjuvant trastuzumab therapy significantly upregulated B7-H4 in the cancer-infiltrating macrophages of HER2⁺ BC patients, which predicted poor trastuzumab response. We suggest that strategies to specifically enhance ADCP activity might be critical to overcoming resistance to HER2 mAb therapies by inhibiting tumor growth and potentially enhance antigen presentation. Furthermore, these results advance the understanding of macrophage plasticity by uncovering a dual role for ADCP in macrophages involving elimination of tumors by engulfing cancer cells while causing a concomitant undesired effect by upregulating immunosuppressive checkpoints.

From the Broad Phase II Trial to Precision Oncology: A Perspective on the Origins of Basket and Umbrella Clinical Trial Designs in Cancer Drug Development

Oncologic phase II trials that evaluate the activity of new therapeutic agents have evolved dramatically over the past 50 years. The standard approach beginning in the late 1960s focused on individual studies that evaluated new anticancer agents against a wide range of both solid and hematopoietic malignancies often in a single "broad phase II trial" that included hundreds of patients; such studies efficiently established the landscape for subsequent development of a specific drug with respect to likely disease focus, toxicity, dose, and schedule. In the 1980s and 1990s, emphasis on histological context drove an explosion in the number of individual phase II trials conducted; despite this increase in trial activity, investigations based on histology per se failed to improve the success rate of new agents brought to the clinic. Over the past 20 years, evolution toward a molecular drug development paradigm has demonstrably improved our ability to select patients more likely to benefit from systemic treatment; simultaneously, technological advances have permitted initial attempts at the rapid assignment of therapy based on predefined molecular characteristics of tumor or germline in broad-based master protocols that are inclusive of many diseases and molecularly characterized disease subsets, akin to but much more sophisticated scientifically than the broad phase II platforms of the past.

HER family in cancer progression: From discovery to 2020 and beyond

The human epidermal growth factor receptor (HER) family of receptor tyrosine kinases (RTKs) are among the first layer of molecules that receive, interpret, and transduce signals leading to distinct cancer cell phenotypes. Since the discovery of the tooth-lid factor-later characterized as the epidermal growth factor (EGF)-and its high-affinity binding EGF receptor, HER kinases have emerged as one of the commonly upregulated or hyperactivated or mutated kinases in epithelial tumors, thus allowing HER1-3 family members to regulate several hallmarks of cancer development and progression. Each member of the HER family exhibits shared and unique structural features to engage multiple receptor activation modes, leading to a range of overlapping and distinct phenotypes. EGFR, the founding HER family member, provided the roadmap for the development of the cell surface RTK-directed targeted cancer therapy by serving as a prototype/precursor for the currently used HER-directed cancer drugs. We herein provide a brief account of the discoveries, defining moments, and historical context of the HER family and guidepost advances in basic, translational, and clinical research that solidified a prominent position of the HER family in cancer research and treatment. We also discuss the significance of HER3 pseudokinase in cancer biology; its unique structural features that drive transregulation among HER1-3, leading to a superior proximal signaling response; and potential role of HER3 as a shared effector of acquired therapeutic resistance against diverse oncology drugs. Finally, we also narrate some of the current drawbacks of HER-directed therapies and provide insights into postulated advances in HER biology with extensive implications of these therapies in cancer research and treatment.

Role of microRNAs in epidermal growth factor receptor signaling pathway in cervical cancer

Cervical cancer is one of the most common disorders in females all around the world. Similar to other types of cancer, several signaling pathways are demonstrated to be involved in the progression of this cancer including ERK/MAPK, PI3K/AKT, apoptotic signaling pathways, Wnt, and epidermal growth factor receptor (EGFR). Various microRNAs (miRNAs) and their target genes involved in cervical cancer have been extracted from the kinds of literature of Scopus, Pubmed and Google scholar databases. Regarding the targets, some of them were found to belong in EGFR signaling pathways. The regulation patterns of these miRNA are different in cervical cancer; however, their main aim is to trigger EGFR signaling to proceed with cancer. Moreover, several predicted miRNAs were found to have some interactions with the differentially expressed genes of cervical cancer which are the members of the EGFR signaling pathway by using miRWalk 3.0 (https://mirwalk.umm.uni-heidelberg.de/) and TargetScan 7.1 (https://www.targetscan.org/vert_71/). Also, the microarray data were obtained from the NCBI-Gene Expression Omnibus (GEO) datasets of cervical cancer. In the present review, we highlight the miRNAs involved in cervical cancer and the role of their targets in the EGFR signaling pathway. Furthermore, some predicted miRNAs were the candidate to target EGFR signaling pathway members differentially expressed in cervical cancer samples compared to normal samples.

HER3 targeting with an antibody-drug conjugate bypasses resistance to anti-HER2 therapies

Despite impressive clinical benefit obtained with anti‐HER2‐targeted therapies, in advances stages, especially in the metastatic setting, HER2‐positive tumors remain incurable. Therefore, it is important to develop novel strategies to fight these tumors, especially when they become resistant to available therapies. We show here that the anti‐HER3 antibody–drug conjugate EV20/MMAF exerted potent anti‐tumoral properties against several models of primary resistance and secondary resistance to common anti‐HER2 available therapies, including trastuzumab, lapatinib, neratinib, and trastuzumab‐emtansine. HER3 was expressed in these HER2⁺ breast cancer cells and knockdown experiments demonstrated that HER3 expression was required for the action of EV20/MMAF. In mice injected with trastuzumab‐resistant HER2⁺ cells, a single dose of EV20/MMAF caused complete and long‐lasting tumor regression. Mechanistically, EV20/MMAF bound to cell surface HER3 and became internalized to the lysosomes. Treatment with EV20/MMAF caused cell cycle arrest in mitosis and promoted cell death through mitotic catastrophe. These findings encourage the clinical testing of EV20/MMAF for several indications in the HER2⁺ cancer clinic, including situations in which HER2⁺ tumors become refractory to approved anti‐HER2 therapies.

Prognostic and therapeutic molecular markers in the clinical management of esophageal cancer

Introduction: Esophageal cancer is a deadly disease with high mortality. Treatment with chemotherapy, radiation, and surgery continues to leave many patients with disease progression and recurrence. Novel treatments are needed for this patient population. The development of molecular markers are important for identifying therapeutic targets, as well as prognosis.Areas covered: This review evaluates three molecular markers in esophageal cancer: HER2, PD-L1, and MSI. The fundamentals of these markers, diagnosis, and rates of occurrence in esophageal cancer are explored. The prognostic potential of these markers is based on existing literature as well as application in clinical trials. Key trial findings pertaining to the therapeutic targets for HER2 and PD-1 as well as the role of MSI are discussed.Expert commentary: Molecular markers are changing the practice for esophageal cancer. Therapeutic targeting for HER2 and PD-L1 have shown positive results in recent clinical trials. Trials evaluating immunotherapy as first-line agents are currently underway.

New HER2-negative breast cancer subtype responsive to anti-HER2 therapy identified

Purpose

HER2 signaling functional activity may be important to measure in addition to HER2 protein quantification when identifying patients eligible for HER2 therapies. A HER2 Signaling Function (CELx HSF) Test for HER2-negative patients uses patient’s live tumor cells on a biosensor to identify patients with abnormally high HER2-related signaling (HSFs+) likely to respond to anti-HER2 therapies.

Methods

The CELx HSF test was employed to: (1) characterize the sensitivity and specificity of the test to detect abnormal levels of HER2 signaling; (2) evaluate the inhibitory effectiveness of five different anti-HER2 therapies; (3) assess the correlation between CELx HSF test detection of abnormal HER2 signaling and response to HER2 therapy using xenograft models; and (4) confirm the prevalence of abnormal HER2 signaling amongst HER2-negative breast cancer patients (HER2−/HSFs+).

Results

HER2−/HSFs+ breast cancer patient samples were identified and showed sensitivity to five approved anti-HER2 therapies. Xenograft studies using both HER2+ and HER2− cell lines confirmed that CELx HER2 signaling status better predicts HER2 inhibitor efficacy than HER2 receptor status. In a study of 114 HER2-negative breast tumor patient samples, 27 (23.7%; 95% CI = 17–32%) had abnormal HER2 signaling (HSFs+). A ROC curve constructed with this dataset projects the CELx HSF Test would have greater than 90% sensitivity and specificity to detect the HER2−/HSFs+ patient population.

Conclusions

The CELx HSF test is a well-characterized functional biomarker assay capable of identifying dynamic HER2-driven signaling dysfunction in tumor cells from HER2-negative breast cancer patients. This test has demonstrated efficacy of various HER2 targeted therapies in live tumor cells from the HSFs+ population and correlated the test result to HER2 drug response in mouse xenograft studies. The proportion of HER2-negative breast cancer patients found to have abnormal HER2 signaling in a 114 patient sample study, 20–25%, is significant. A clinical trial to evaluate the efficacy of anti-HER2 therapies in this patient population is warranted.

Electronic supplementary material

The online version of this article (10.1007/s00432-020-03144-7) contains supplementary material, which is available to authorized users.

Preliminary evaluation of HER-2/neu oncogene and epidermal growth factor receptor expression in normal and neoplastic human ovaries

The HER-2/neu oncogene (a member of the Erb-like oncogene family) is distinct from but closely related to the c-erb B gene which encodes the epidermal growth factor receptor (EGFr). HER-2/neu gene amplification was found in a large number of mammary carcinomas and there was a strong correlation between this phenomenon and poor prognosis. In our study HER-2/neu oncogene expression was determined in 16 malignant ovarian tumors, 2 ovarian lymphomas and 5 normal ovaries. The HER-2/neu gene was found both in normal ovaries and malignant tumors, without any apparent difference among the various histological types. In all the specimens examined, HER-2/neu expression did not seem to be related to EGF binding capacity.

Genomics and the History of Precision Oncology

Progress toward the implementation of a molecular characterization paradigm in cancer drug development over the past 20 years has markedly enhanced our capability to select patients who are more likely to benefit from cancer therapy. Improvements in genomic and related diagnostic testing platforms have permitted evaluation of the efficacy of treatment assignment based on predefined biologic features of a patient's tumor or germline using master protocols that may include many malignancies and their molecularly characterized subsets. With this approach, a wide range of new targeted and immunologic treatment approaches have been defined for patients who, heretofore, lacked effective therapeutic options.

HER2-Targeted Therapy in Osteosarcoma

In this chapter, we will review studies of HER2 in osteosarcoma and discuss the controversies that have existed in this field. Our present understanding of HER2 in the context of osteosarcoma is that it is expressed on a subset of patient samples, but that expression is not prognostic. We will review the two trials that have been conducted in osteosarcoma which have targeted HER2. Use of an antibody, trastuzumab, did not suggest activity, but a smaller study using HER2-targeted CAR T cells suggested activity may be present. A trial of an antibody-drug conjugate targeting HER2 for recurrent osteosarcoma is under consideration. Trials targeting other surface proteins for the treatment of osteosarcoma have occurred or are in development. Indeed, this leads us to discuss in a broader fashion therapeutic approaches to targeting surface proteins. It is hoped that some of these approaches will lead to new effective therapies for patients with osteosarcoma.

Antiproliferative activity of new pentacyclic triterpene and a saponin from Gladiolus segetum Ker-Gawl corms supported by molecular docking study

A new triterpenoidal saponin identified as 3-O-[β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-β-d-xylopyranosyl]-2β,3β,16α-trihydroxyolean-12-en-23,28-dioic acid-28-O-α-l-rhamnopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 2)-α-l-arabinopyranoside 1 together with a new oleanane triterpene identified as 2β,3β,13α,22α-tetrahydroxy olean-23,28-dioic acid 2 and 6 known compounds (3–8) have been isolated from Gladiolus segetum Ker-Gawl corms. The structural elucidation of the isolated compounds was confirmed using different chemical and spectroscopic methods, including 1D and 2D NMR experiments as well as HR-ESI-MS. Moreover, the in vitro cytotoxic activity of the fractions and that of the isolated compounds 1–8 were investigated against five human cancer cell lines (PC-3, A-549, HePG-2, MCF-7 and HCT-116) using doxorubicin as a reference drug. The results showed that the saponin fraction exhibited potent in vitro cytotoxic activity against the five human cancer cell lines, whereas the maximum activity was exhibited against the PC-3 and A-549 cell lines with the IC₅₀ values of 1.13 and 1.98 μg mL⁻¹, respectively. In addition, compound 1 exhibited potent activity against A-549 and PC-3 with the IC₅₀ values of 2.41 μg mL⁻¹ and 3.45 μg mL⁻¹, respectively. Interestingly, compound 2 showed the maximum activity against PC-3 with an IC₅₀ of 2.01 μg mL⁻¹. These biological results were in harmony with that of the molecular modeling study, which showed that the cytotoxic activity of compound 2 might occur through the inhibition of the HER-2 enzyme.

A new triterpenoidal saponin 1, a new oleanane triterpene 2, and 6 known compounds (3–8) have been isolated from Gladiolus segetum Ker-Gawl corms.

CD47 blockade augmentation of trastuzumab antitumor efficacy dependent on antibody-dependent cellular phagocytosis

The HER2-specific monoclonal antibody (mAb), trastuzumab, has been the mainstay of therapy for HER2+ breast cancer (BC) for approximately 20 years. However, its therapeutic mechanism of action (MOA) remains unclear, with antitumor responses to trastuzumab remaining heterogeneous and metastatic HER2+ BC remaining incurable. Consequently, understanding its MOA could enable rational strategies to enhance its efficacy. Using both murine and human versions of trastuzumab, we found its antitumor activity dependent on Fcγ receptor stimulation of tumor-associated macrophages (TAMs) and antibody-dependent cellular phagocytosis (ADCP), but not cellular cytotoxicity (ADCC). Trastuzumab also stimulated TAM activation and expansion, but did not require adaptive immunity, natural killer cells, and/or neutrophils. Moreover, inhibition of the innate immune ADCP checkpoint, CD47, significantly enhanced trastuzumab-mediated ADCP and TAM expansion and activation, resulting in the emergence of a unique hyperphagocytic macrophage population, improved antitumor responses, and prolonged survival. In addition, we found that tumor-associated CD47 expression was inversely associated with survival in HER2+ BC patients and that human HER2+ BC xenografts treated with trastuzumab plus CD47 inhibition underwent complete tumor regression. Collectively, our study identifies trastuzumab-mediated ADCP as an important antitumor MOA that may be clinically enabled by CD47 blockade to augment therapeutic efficacy.

Visualisation of HER2 homodimers in single cells from HER2 overexpressing primary formalin fixed paraffin embedded tumour tissue

Background

HER2 is considered as one of the most important, predictive biomarkers in oncology. The diagnosis of HER2 positive cancer types such as breast- and gastric cancer is usually based on immunohistochemical HER2 staining of tumour tissue. However, the current immunohistochemical methods do not provide localized information about HER2’s functional state. In order to generate signals leading to cell growth and proliferation, the receptor spontaneously forms homodimers, a process that can differ between individual cancer cells.

Materials and methods

HER2 overexpressing tumour cells were dissociated from formalin-fixed paraffin-embedded (FFPE) patient’s biopsy sections, subjected to a heat-induced antigen retrieval procedure, and immobilized on microchips. HER2 was specifically labelled via a two-step protocol involving the incubation with an Affibody-biotin compound followed by the binding of a streptavidin coated quantum dot (QD) nanoparticle. Cells with membrane bound HER2 were identified using fluorescence microscopy, coated with graphene to preserve their hydrated state, and subsequently examined by scanning transmission electron microscopy (STEM) to obtain the locations at the single molecule level. Label position data was statistically analysed via the pair correlation function, yielding information about the presence of HER2 homodimers.

Results

Tumour cells from two biopsies, scored HER2 3+, and a HER2 negative control sample were examined. The specific labelling protocol was first tested for a sectioned tissue sample of HER2-overexpressing tumour. Subsequently, a protocol was optimized to study HER2 homodimerization in single cells dissociated from the tissue section. Electron microscopy data showed membrane bound HER2 in average densities of 201–689 proteins/μm². An automated, statistical analysis of well over 200,000 of measured protein positions revealed the presence of HER2 homodimers in 33 and 55% of the analysed images for patient 1 and 2, respectively.

Conclusions

We introduced an electron microscopy method capable of measuring the positions of individually labelled HER2 proteins in patient tumour cells from which information about the functional status of the receptor was derived. This method could take HER2 testing a step further by examining HER2 homodimerization directly out of tumour tissue and may become important for adjusting a personalized antibody-based drug therapy.

Electronic supplementary material

The online version of this article (10.1186/s10020-019-0108-z) contains supplementary material, which is available to authorized users.

Emergence of ERBB2 Mutation as a Biomarker and an Actionable Target in Solid Cancers

The oncogenic role ERBB2 amplification is well established in breast and gastric cancers. This has led to the development of a well-known portfolio of monoclonal antibodies and kinase inhibitors targeting the ERBB2 kinase. More recently, activating mutations in the ERBB2 gene have been increasingly reported in multiple solid cancers and were shown to play an oncogenic role similar to that of ERBB2 amplification. Thus, ERBB2 mutations define a distinct molecular subtype of solid tumors and serve as actionable targets. However, efforts to target ERBB2 mutation has met with limited clinical success, possibly because of their low frequency, inadequate understanding of the biological activity of these mutations, and difficulty in separating the drivers from the passenger mutations. Given the current impetus to deliver molecularly targeted treatments for cancer, there is an important need to understand the therapeutic potential of ERBB2 mutations. Here we review the distribution of ERBB2 mutations in different tumor types, their potential as a novel biomarker that defines new subsets in many cancers, and current data on preclinical and clinical efforts to target these mutations. IMPLICATIONS FOR PRACTICE: A current trend in oncology is to identify novel genomic drivers of solid tumors and developing precision treatments that target them. ERBB2 amplification is an established therapeutic target in breast and gastric cancers, but efforts to translate this finding to other solid tumors with ERBB2 amplification have not been effective. Recently the focus has turned to targeting activating ERBB2 mutations. The year 2018 marked an important milestone in establishing ERBB2 mutation as an important actionable target in multiple cancer types. There have been several recent preclinical and clinical studies evaluating ERBB2 mutation as a therapeutic target with varying success. With increasing access to next-generation sequencing technologies in the clinic, oncologists are frequently identifying activating ERBB2 mutations in patients with cancer. There is a significant need both from the clinician and bench scientist perspectives to understand the current state of affairs for ERBB2 mutations.

Emerging Allosteric Mechanism of EGFR Activation in Physiological and Pathological Contexts

Protein kinases are key players in signal transduction pathways where they are crafted into two functional states. In response to growth factor binding stimulus, epidermal growth factor receptor (EGFR), which is physiologically populated in an autoinhibited inactive state, becomes active. Here, we outline a simple allostery scheme to clarify how an extracellular (ligand-dependent) binding event activates the intracellular EGFR kinase domain via (dimer-dependent) asymmetric dimerization, as well as how pathologically overexpressed EGFR or constitutively active mutants, leads to oncogenic pathway activation. Our underlying allosteric activation mechanism derives from a collection of inactive versus active EGFR structural, biochemical (negatively cooperative ligand binding), and biophysical (weak coupling between extracellular and intracellular kinase dimerization) data. The emerging structural insight reveals that ligand-dependent physiological activation is an outside-in allosteric activation with strong structural coupling across the membrane. In contrast, ligand-independent pathological activation is a weak inside-out activation mediated by intracellular kinase dimerization, which is structurally accommodated by additional extracellular dimers.

TRAIL receptor activation overcomes resistance to trastuzumab in HER2 positive breast cancer cells

The appearance of resistance to the anti-HER2 targeted drug trastuzumab constitutes, nowadays, an important challenge in the oncology clinic. To fight such resistance, we searched for potential vulnerabilities in cells resistant to that drug. To that end, we used cell lines primary resistant to trastuzumab, as well as cells made secondarily resistant to the drug upon continuous exposure. Using genomic and proteomic approaches, a deregulation in cell death pathways was identified in trastuzumab-resistant cells. More precisely, an increased response to the death factor TRAIL, caused by an increase in the cellular receptors for this factor, was observed. In parallel, a decrease in inhibitory components of the pathway was detected. This combination produces a more efficient assembly of the functional complex in the trastuzumab-resistant cells that translates in the observed increased response to TRAIL. Analysis of HER2 positive patient samples confirmed deregulation of this pathway in trastuzumab-resistant patients. Taken together our data identify a vulnerability of trastuzumab-resistant cells that could be used to design new targeted therapies in that context.

Conditional knockout of SHP2 in ErbB2 transgenic mice or inhibition in HER2-amplified breast cancer cell lines blocks oncogene expression and tumorigenesis

Overexpression of the human epidermal growth factor receptor 2 (HER2) is the cause of HER2-positive breast cancer (BC). Although HER2-inactivating therapies have benefited BC patients, development of resistance and disease recurrence have been the major clinical problems, pointing to a need for alternative therapeutic strategies. For that to happen, proteins that play critical roles in the biology of HER2-induced tumorigenesis have to be identified and characterized. Here, we show that the Src homology phosphotyrosyl phosphatase 2 (Shp2) encoded by the Ptpn11 gene is a requisite for ErbB2-induced tumorigenesis. We report that conditional knockout of Shp2 alleles in the ErbB2 BC model mice abrogates mammary tumorigenesis by blocking the expression of the ErbB2 transgene. We also show that inhibition of SHP2 encoded by the PTPN11 gene in the HER2-amplified BC cells induces a normal-like cellular phenotype and suppresses tumorigenesis and metastasis by blocking HER2 overexpression. These findings demonstrate that ErbB2-induced tumors in mice or xenograft tumors induced by transplantation of HER2-amplified BC cells are vulnerable to SHP2 inhibition since it abrogates the expression of the very oncogene that causes of the disease. This report paves the way for developing SHP2-targeting therapies for BC treatment in the future.

Mechanisms Underlying the Action and Synergism of Trastuzumab and Pertuzumab in Targeting HER2-Positive Breast Cancer

Human epidermal growth factor receptor (HER) 2 (HER2) is overexpressed in 20⁻30% of breast cancers. HER2 is a preferred target for treating HER2-positive breast cancer. Trastuzumab and pertuzumab are two HER2-targeted monoclonal antibodies approved by the Food and Drug Administration (FDA) to use as adjuvant therapy in combination with docetaxel to treat metastatic HER2-positive breast cancer. Adding the monoclonal antibodies to treatment regimen has changed the paradigm for treatment of HER2-positive breast cancer. Despite improving outcomes, the percentage of the patients who benefit from the treatment is still low. Continued research and development of novel agents and strategies of drug combinations is needed. A thorough understanding of the molecular mechanisms underlying the action and synergism of trastuzumab and pertuzumab is essential for moving forward to achieve high efficacy in treating HER2-positive breast cancer. This review examined and analyzed findings and hypotheses regarding the action and synergism of trastuzumab and pertuzumab and proposed a model of synergism based on available information.

Fatty Acid Synthase (Fas) Predictive Strength in Poorly Differentiated Early Breast Carcinomas

Aims and background

Many normal and human cancer tissues express fatty acid synthase (FAS), the major enzyme required for endogenous fatty acid biosynthesis. Strong expression of FAS seems to be associated with a poor prognosis. This study examines the strength of FAS and other common markers of relapse in poorly differentiated breast carcinoma.

Materials and methods

Fifty-one patients with poorly differentiated ductal infiltrating breast carcinomas were followed up for more than 10 years. Immunohistochemical detection of FAS was associated with morphological features of the tumors, with immunohistochemical expression of c-erbB-2, cathepsin D, estrogen and progesterone receptor status and with DNA ploidy in order to detect a statistical correlation.

Results

The chi-square test revealed a correlation between FAS and peritumoral lymphatic vessel invasion (PLVI) (P = 0.001). Univariate analysis showed that FAS was correlated with disease-free survival (DFS) (P = 0.0001). Other prognosticators associated with DFS were PLVI (P = 0.002), estrogen (P = 0.008) and progesterone receptor status (P = 0.007). Bivariate analysis showed that FAS was a further prognostic discriminant of DFS within the ER, PgR and PLVI subsets.

Discussion

FAS is a reliable prognosticator of recurrence in poorly differentiated early breast carcinomas. Association of FAS with PLVI may be useful to plan a correct follow-up in patients with breast neoplasms.

Nonhistone targets of KAT2A and KAT2B implicated in cancer biology 1

Lysine acetylation is a critical post-translation modification that can impact a protein's localization, stability, and function. Originally thought to only occur on histones, we now know thousands of nonhistone proteins are also acetylated. In conjunction with many other proteins, lysine acetyltransferases (KATs) are incorporated into large protein complexes that carry out these modifications. In this review we focus on the contribution of two KATs, KAT2A and KAT2B, and their potential roles in the development and progression of cancer. Systems biology demands that we take a broad look at protein function rather than focusing on individual pathways or targets. As such, in this review we examine KAT2A/2B-directed nonhistone protein acetylations in cancer in the context of the 10 "Hallmarks of Cancer", as defined by Hanahan and Weinberg. By focusing on specific examples of KAT2A/2B-directed acetylations with well-defined mechanisms or strong links to a cancer phenotype, we aim to reinforce the complex role that these enzymes play in cancer biology.

Preliminary evaluation of HER-2/neu oncogene and epidermal growth factor receptor expression in normal and neoplastic human ovaries

The HER-2/neu oncogene (a member of the Erb-like oncogene family) is distinct from but closely related to the c-erb B gene which encodes the epidermal growth factor receptor (EGFr). HER-2/neu gene amplification was found in a large number of mammary carcinomas and there was a strong correlation between this phenomenon and poor prognosis. In our study HER-2/neu oncogene expression was determined in 16 malignant ovarian tumors, 2 ovarian lymphomas and 5 normal ovaries. The HER-2/neu gene was found both in normal ovaries and malignant tumors, without any apparent difference among the various histological types. In all the specimens examined, HER-2/neu expression did not seem to be related to EGF binding capacity.