Beyond HER2: Targeting the ErbB receptor family in breast cancer

PCSK9 Promotes the Malignancy of Triple-negative Breast Cancer Cells by Reducing Cholesterol Levels at the Plasma Membrane to Activate EGFR and HER3

Triple-negative breast cancer (TNBC) is a highly heterogeneous and clinically aggressive disease with the highest mortality rate among all subtypes of breast cancer. To discover new driver genes for metastatic TNBC, this work compares the transcription profiles of MDA-MB-231-GFP cells and 231-GFP-derived lung metastatic cells (4-11). Results reveal that proprotein convertase subtilisin/kexin type 9 (PCSK9) is highly upregulated in 4-11 cells. Knockdown of PCSK9 greatly decreases the tumorigenic and metastatic potential of 4-11 cells, whereas overexpression of PCSK9 significantly enhances tumor maliganancy. Mechanistically, the binding of PCSK9 to the low-density lipoprotein receptor (LDLR) results in decreased LDLR at the plasma membrane, which further decreases cholesterol and lipid raft in the plasma membrane and activates human epidermal growth factor receptor 1 and 3 (EGFR and HER3). Subsequently, phosphorylated EGFR and HER3 activate the Src/ERK/c-Jun to increase the levels of cyclin D3 and vimentin and thereby enhance cell growth and metastasis. Metadata analyses also reveal that TNBC patients with high PCSK9 expression exhibited worse clinical outcomes. Taken together, these findings not only reveal a novel mechanism by which PCSK9 promotes the malignant potential of TNBC but also indicate that PCSK9 is a potential therapeutic target for treating TNBC patients.

PAK5 promotes the trastuzumab resistance by increasing HER2 nuclear accumulation in HER2-positive breast cancer

Nuclear HER2 (N-HER2) predicts resistance to HER2-targeted therapy and poor prognosis of breast cancer patients, and the underlying mechanisms remain unclear. Here, we show that high expression of p21-activated kinase 5 (PAK5) is associated with HER2-targeted therapy resistance and poor outcomes of breast cancer patients. Excitingly, we find an increase in N-HER2 protein expression in patients with high PAK5 expression, who demonstrate resistance to trastuzumab treatment. PAK5 phosphorylates methyltransferase METTL14 on serine 399 to enhance m6A modification of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), leading to increased MALAT1 stability. The stabilized MALAT1 inhibits ubiquitin-proteasomal degradation of the N-HER2 by affecting the interaction of deubiquitinase USP8 and N-HER2, thereby promoting N-HER2 accumulation. Moreover, HER2 upregulates the expression of PAK5 and MALAT1, activating the HER2-MALAT1 positive feedback loop. Importantly, PAK5 promotes the therapeutic resistance of HER2-positive breast cancer cells by increasing N-HER2 protein both in vitro and vivo. These findings highlight PAK5 as a therapeutic target for combating trastuzumab resistance in HER2-positive breast cancer.

HER2-positive gastric cancer: from targeted therapy to CAR-T cell therapy

Gastric cancer (GC) ranks as the fifth most prevalent cancer on a global scale, with HER2-positive GC representing a distinct subtype that exhibits more intricate biological characteristics. Conventional chemotherapy typically exhibits restricted efficacy in the management of HER2-positive GC. In light of the incessant advancement in molecular targeted therapies, targeting HER2 has emerged as a promising therapeutic approach for this subtype. The advent of antibody-drug conjugates (ADCs) and chimeric antigen receptor T-cell therapy (CAR-T) has furnished novel treatment alternatives for HER2-positive GC. Nevertheless, owing to the pronounced heterogeneity of GC and the complex tumor microenvironment, drug resistance frequently emerges, thereby substantially influencing the effectiveness of HER2-targeted therapy. This article comprehensively summarizes and deliberates upon the strategies of HER2-targeted therapy as well as the underlying resistance mechanisms.

ERBB3-related gene PBX1 is associated with prognosis in patients with HER2-positive breast cancer

BACKGROUND

HER2-positive breast cancer (BC) is a subtype of breast cancer. Increased ERBB3 expression has been implicated as a potential cause of resistance to other HER-targeted therapies. Our study aimed to screen and validate prognostic markers associated with ERBB3 expression by bioinformatics and affecting the prognosis of HER2 staging.

METHODS

Analyzing differences in ERBB3-related groups. ERBB3 expression-related differentially expressed genes (DEGs) were identified and intersected with survival status-related DEGs to obtain intersected genes. Three algorithms, LASSO, RandomForest and XGBoost were combined to identify the signature genes. we construct risk models and generate ROC curves for prediction. Furthermore, we delve into the immunological traits, correlations, and expression patterns of signature genes by conducting a comprehensive analysis that encompasses immune infiltration analysis, correlation analysis, and differential expression analysis.

RESULTS

Significant variability in ERBB3 expression and prognosis in high and low ERBB3 expression groups. Twenty-five candidate DEGs were identified by intersecting ERBB3-related DEGs with survival-related DEGs. Utilizing three distinct machine learning algorithms, we identified three signature genes-PBX1, IGHM, and CXCL13-that exhibited significant diagnostic value within the diagnostic model. In addition, the risk model had better prognostic and predictive effects, and the immune infiltration analysis showed that IGHM, CXCL13 might affect the proliferation of BC cells through immune cells. Functional studies demonstrated that interference with PBX1 inhibited the proliferation, migration, and epithelial-mesenchymal transition process of HER2-positive BC cells.

CONCLUSION

PBX1, IGHM and CXCL13 are associated with the expression level of the ERBB3 and are prognostic markers for HER2-positive in BC, which may play an important role in the development and progression of BC.

Dysregulated Signaling Pathways in Canine Mammary Tumor and Human Triple Negative Breast Cancer: Advances and Potential Therapeutic Targets

In 2022, human breast cancer (HBC) and canine mammary tumors (CMTs) remained the most prevalent malignant tumors worldwide, with high recurrence and lethality rates, posing a significant threat to human and dog health. The development of breast cancer involves multiple signaling pathways, highlighting the need for effective inhibitory drugs that target key proteins in these pathways. This article reviews the dysregulation of the EGFR, PI3K/AKT/mTOR, Hippo, pyroptosis, and PD-1/PD-L1 signaling pathways in HBC and CMT, as well as the corresponding drugs used to inhibit tumor growth, with the aim of providing theoretical support for the development of more efficient drugs.

Performance of a HER2 testing algorithm tailored for urothelial bladder cancer: A Bi-centre study

Aims

This study aimed to develop an AI algorithm for automated HER2 scoring in urothelial bladder cancer (UBCa) and assess the interobserver agreement using both manual and AI-assisted methods based on breast cancer criteria.

Methods and Results

We utilized 330 slides from two institutions for initial AI development and selected 200 slides for the ring study, involving six pathologists (3 senior, 3 junior). Our AI algorithm achieved high accuracy in two independent tests, with accuracies of 0.94 and 0.92. In the ring study, the AI-assisted method improved both accuracy (0.66 vs 0.94) and consistency (kappa=0.48; 95 % CI, 0.443-0.526 vs kappa=0.87; 95 % CI, 0.852-0.885) compared to manual scoring, especially in HER2-low cases (F1-scores: 0.63 vs 0.92). Additionally, in 62.3 % of heterogeneous HER2-positive cases, the interpretation accuracy significantly improved (0.49 vs 0.93). Pathologists, particularly junior ones, experienced enhanced accuracy and consistency with AI assistance.

Conclusions

This is the first study to provide a quantification algorithm for HER2 scoring in UBCa to assist pathologists in diagnosis. The ring study demonstrated that HER2 scoring based on breast cancer criteria can be effectively applied to UBCa. Furthermore, AI assistance significantly improves the accuracy and consistency of interpretations among pathologists with varying levels of experience, even in heterogeneous cases.

GPR37 promotes colorectal cancer against ferroptosis by reprogramming lipid metabolism via p38-SCD1 axis

Colorectal cancer (CRC) is a prevalent malignant tumor worldwide, leading to significant morbidity and disease burden. Diagnostic indicators and treatment objectives for CRC are urgently needed. This study demonstrates that GPR37, a GPCR receptor, is highly expressed in CRC. Depletion of GPR37 significantly reduced CRC tumor cell growth both in vitro and in vivo. Further tests showed that GPR37 protects cancer cells from ferroptosis by upregulating SCD1 expression, thereby modulating lipid metabolism, suppressing the level of reactive oxygen species, and mitigating ferroptosis. Mechanistic studies have shown that GPR37 modulates lipid metabolism in tumor cells by promoting SCD1 transcription via the MAPK-p38 signaling pathway. Our results reveal the pro-carcinogenic effect of GPR37 in primary CRC and suggest that targeting GPR37 could be a potential therapeutic target for CRC.

SON is an essential RNA splicing factor promoting ErbB2 and ErbB3 expression in breast cancer

BACKGROUND

In breast cancer, ErbB receptors play a critical role, and overcoming drug resistance remains a major challenge in the clinic. However, intricate regulatory mechanisms of ErbB family genes are poorly understood. Here, we demonstrate SON as an ErbB-regulatory splicing factor and a novel therapeutic target for ErbB-positive breast cancer.

METHODS

SON and ErbB expression analyses using public database, patient tissue microarray, and cell lines were performed. SON knockdown assessed its impact on cell proliferation, apoptosis, kinase phosphorylation, RNA splicing, and in vivo tumour growth. RNA immunoprecipitation was performed to measure SON binding.

RESULTS

SON is highly expressed in ErbB2-positive breast cancer patient samples, inversely correlating with patient survival. SON knockdown induced intron retention in selective splice sites within ErbB2 and ErbB3 transcripts, impairing effective RNA splicing and reducing protein expression. SON disruption suppressed downstream kinase signalling of ErbB2/3, including the Akt, p38, and JNK pathways, with increased vulnerability in ErbB2-positive breast cancer cells compared to ErbB2-negative cells. SON silencing in ErbB2-positive breast cancer xenografts led to tumour regression in vivo.

CONCLUSION

We identified SON as a novel RNA splicing factor that plays a critical role in regulating ErbB2/3 expression, suggesting SON is an ideal therapeutic target in ErbB2-positive breast cancers.

Survival prediction and analysis of drug-resistance genes in HER2-positive breast cancer

Despite the approval of several therapeutic agents for HER2-positive breast cancer, drug resistance remains a significant challenge, hindering the patient's prognosis. Thus, our study aimed to establish a risk model to predict the prognosis of patients and identify key genes regulating drug resistance in HER2-positive breast cancer. Utilizing data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), a predictive model was constructed based on 5 drug resistance-related genes, which demonstrated a notable capacity to indicate the survival rates of patients. Besides, through eccDNA and transcriptome sequencing of drug-sensitive and resistant cancer cells, 3 significant DEGs were identified: MED1, MED24, and NMD3. Among them, MED1 showed the most significant elevation in drug-resistance cells, highlighting its crucial role in mediating drug resistance. MED1 may serve as a valuable target for alleviating drug resistance in HER2-positive breast cancer.

Biochemical Pathways Delivering Distinct Glycosphingolipid Patterns in MDA-MB-231 and MCF-7 Breast Cancer Cells

The complex structure of glycosphingolipids (GSLs) supports their important role in cell function as modulators of growth factor receptors and glutamine transporters in plasma membranes. The aberrant composition of clustered GSLs within signaling platforms, so-called lipid rafts, inevitably leads to tumorigenesis due to disturbed growth factor signal transduction and excessive uptake of glutamine and other molecules needed for increased energy and structural molecule cell supply. GSLs are also involved in plasma membrane processes such as cell adhesion, and their transition converts cells from epithelial to mesenchymal with features required for cell migration and metastasis. Glutamine activates the mechanistic target of rapamycin complex 1 (mTORC1), resulting in nucleotide synthesis and proliferation. In addition, glutamine contributes to the cancer stem cell GD2 ganglioside-positive phenotype in the triple-negative breast cancer cell line MDA-MB-231. Thieno[2,3-b]pyridine derivative possesses higher cytotoxicity against MDA-MB-231 than against MCF-7 cells and induces a shift to aerobic metabolism and a decrease in S(6)nLc4Cer GSL-positive cancer stem cells in the MDA-MB-231 cell line. In this review, we discuss findings in MDA-MB-231, MCF-7, and other breast cancer cell lines concerning their differences in growth factor receptors and recent knowledge of the main biochemical pathways delivering distinct glycosphingolipid patterns during tumorigenesis and therapy.

Causal role of blood metabolites in HER-positive and HER-negative breast cancer: a Mendelian randomization (MR) study

BACKGROUND

Previous studies provide evidence that in vivo metabolites are associated with breast cancer (BC). However, the causal relationship between blood metabolites and BC remains unclear.

METHOD

Comprehensive two-sample Mendelian randomization analysis was conducted to determine the causal association between 1400 publicly available genetic data on metabolic factors and human epidermal growth factor receptor positive (HER+) BC or HER- BC in this study.

RESULT

Epiandrosterone sulfate levels (OR = 1.07, 95% CI = 1.02 ~ 1.10, p = 0.0013), 5alpha-androstan-3beta,17beta-diol monosulfate (2) levels (OR = 1.07, 95% CI = 1.03 ~ 1.12, p = 0.0012), glycohyocholate levels (OR = 0.85, 95% CI = 0.77 ~ 0.93, p = 0.0007) and etiocholanolone glucuronide levels (OR = 1.12, 95% CI = 1.05 ~ 1.20, p = 0.0013) were causally correlated with HER+ BC. 5 metabolites were causally correlated with HER- BC: Vanillic acid glycine levels (OR = 1.14, 95% CI = 1.06 ~ 1.22, p = 0.0003), Thyroxine levels (OR = 1.26, 95% CI = 1.11 ~ 1.44, p = 0.0004), 1-palmitoyl-2-linoleoyl-GPI (16:0/18:2) levels (OR = 0.86, 95% CI = 0.79 ~ 0.94, p = 0.0010), N-acetylphenylalanine levels (OR = 1.12, 95% CI = 1.05 ~ 1.19, p = 0.0007) and Glucose-to-mannose ratio (OR = 1.15, 95% CI = 1.06 ~ 1.24, p = 0.0008). Two common causally related metabolites were identified: Gamma-glutamyl glutamate and X-12849 levels.

CONCLUSIONS

Our study has respectively demonstrated the connection between blood metabolites and HER+ or HER- BC by genetic means, thereby offering opportunities for therapeutic targets.

ERBB2 Targeting Reveals a Significant Suppression of Tumorigenesis in Murine Endometrial Cancer with Pten Mutation

Endometrial cancer is the most common gynecologic malignancy. PTEN is a negative regulator of PI3K signaling and is deficient in > 50% of primary human endometrial cancer. Amplification of ERBB2 promotes tumorigenesis and pathogenesis of several human cancers. However, the effect of ERBB2 targeting has not been studied in endometrial cancer with PTEN mutations. The murine model Pgrcre/+Erbb2f/fPtenf/f (Erbb2d/d Ptend/d) was developed to evaluate the effect of ERBB2 targeted therapy in endometrial cancer with PTEN deficiency. Histopathological and molecular analysis was performed for Ptend/d and Erbb2d/dPtend/d mice. Histopathological analysis revealed that Erbb2d/dPtend/d mice significantly reduced development and progression of endometrial cancer compared to Ptend/d mice. Furthermore, percentage of proliferative cells in Erbb2d/dPtend/d mice revealed anti-tumorigenic effect of Erbb2 ablation compared to Ptend/d mice. Our results demonstrate that Erbb2 ablation reveals a significant suppression of tumorigenesis on endometrial cancer of Ptend/d mice. Our results suggest that Erbb2 functions as an oncogene in endometrial cancer of Ptend/d mice implying that Erbb2 targeting can be used as an effective therapeutic approach for treatment of endometrial cancer with PTEN deficiency to hinder cancer development.

Patritumab deruxtecan in HER2-negative breast cancer: part B results of the window-of-opportunity SOLTI-1805 TOT-HER3 trial and biological determinants of early response

Patritumab deruxtecan (HER3-DXd) exhibits promising efficacy in breast cancer, with its activity not directly correlated to baseline ERBB3/HER3 levels. This research investigates the genetic factors affecting HER3-DXd's response in women with early-stage hormone receptor-positive and HER2-negative (HR+/HER2-) breast cancer. In the SOLTI-1805 TOT-HER3 trial, a single HER3-DXd dose was administered to 98 patients across two parts: 78 patients received 6.4 mg/kg (Part A), and 44 received a lower 5.6 mg/kg dose (Part B). The CelTIL score, measuring tumor cellularity and infiltrating lymphocytes from baseline to day 21, was used to assess drug activity. Part A demonstrated increased CelTIL score after one dose of HER3-DXd. Here we report CelTIL score and safety for Part B. In addition, the exploratory analyses of part A involve a comprehensive study of gene expression, somatic mutations, copy-number segments, and DNA-based subtypes, while Part B focuses on validating gene expression. RNA analyses show significant correlations between CelTIL responses, high proliferation genes (e.g., CCNE1, MKI67), and low expression of luminal genes (e.g., NAT1, SLC39A6). DNA findings indicate that CelTIL response is significantly associated with TP53 mutations, proliferation, non-luminal signatures, and a distinct DNA-based subtype (DNADX cluster-3). Critically, low HER2DX ERBB2 mRNA, correlates with increased HER3-DXd activity, which is validated through in vivo patient-derived xenograft  models. This study proposes chemosensitivity determinants, DNA-based subtype classification, and low ERBB2 expression as potential markers for HER3-DXd activity in HER2-negative breast cancer.

A Preliminary Evaluation of the Prognostic Role of HER-2 and HER-3 Immunohistochemical Expression in Canine Melanomas

Canine melanoma is a malignant and aggressive neoplasm showing clinical, histological, and molecular features similar to the human counterpart. In human medicine, epidermal growth factor receptors (EGFRs) have already been suggested as prognostic markers and potential therapeutic targets in cutaneous melanoma. The aim of this study was to evaluate the expression of HER-2 and HER-3 in canine melanomas by immunohistochemistry and correlate their expression to the clinicopathological parameters of the examined tumors. Thirty-seven canine melanoma samples were recruited. Data regarding signalment and clinical parameters were also collected. The population was composed of 18 cutaneous, 16 oral/mucosal, and three digital/foot pad melanomas. Histopathological investigations were carried out to analyze histological type, ulceration, and mitotic count. On each sample, immunohistochemistry was performed using an anti-Melan-A or anti-Melanoma antigen, i.e., anti-HER-2 and anti-HER-3 antibodies. HER-2 and HER-3 positivity were classified using already established scoring criteria and a statistical analysis was carried out. The results highlighted that HER-2 expression was observed in 48.6% of the samples and HER-3 expression in 18.9%. The highest HER 2 score (3+) was recorded in 16.2% of the samples, while the coexpression of the two receptors was detected in 13.5% of the samples. A statistically significant association (p < 0.05) was observed between the expression of HER-2 and HER-3 and the presence of ulceration in oromucosal tumors. This work confirms the expression of HER-2 and HER-3 in canine melanomas and suggests a putative association with negative prognostic parameters. Further studies are necessary to strengthen these data by increasing the samples size and combining pathological examinations with molecular biology in the investigation of EGFR family receptors.

Bispecific antibody drug conjugates: Making 1+1>2

Bispecific antibody‒drug conjugates (BsADCs) represent an innovative therapeutic category amalgamating the merits of antibody‒drug conjugates (ADCs) and bispecific antibodies (BsAbs). Positioned as the next-generation ADC approach, BsADCs hold promise for ameliorating extant clinical challenges associated with ADCs, particularly pertaining to issues such as poor internalization, off-target toxicity, and drug resistance. Presently, ten BsADCs are undergoing clinical trials, and initial findings underscore the imperative for ongoing refinement. This review initially delves into specific design considerations for BsADCs, encompassing target selection, antibody formats, and the linker-payload complex. Subsequent sections delineate the extant progress and challenges encountered by BsADCs, illustrated through pertinent case studies. The amalgamation of BsAbs with ADCs offers a prospective solution to prevailing clinical limitations of ADCs. Nevertheless, the symbiotic interplay among BsAb, linker, and payload necessitates further optimizations and coordination beyond a simplistic "1 + 1" to effectively surmount the extant challenges facing the BsADC domain.

HER3-targeted therapy: the mechanism of drug resistance and the development of anticancer drugs

Human epidermal growth factor receptor 3 (HER3), which is part of the HER family, is aberrantly expressed in various human cancers. Since HER3 only has weak tyrosine kinase activity, when HER3 ligand neuregulin 1 (NRG1) or neuregulin 2 (NRG2) appears, activated HER3 contributes to cancer development and drug resistance by forming heterodimers with other receptors, mainly including epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2). Inhibition of HER3 and its downstream signaling, including PI3K/AKT, MEK/MAPK, JAK/STAT, and Src kinase, is believed to be necessary to conquer drug resistance and improve treatment efficiency. Until now, despite multiple anti-HER3 antibodies undergoing preclinical and clinical studies, none of the HER3-targeted therapies are licensed for utilization in clinical cancer treatment because of their safety and efficacy. Therefore, the development of HER3-targeted drugs possessing safety, tolerability, and sensitivity is crucial for clinical cancer treatment. This review summarizes the progress of the mechanism of HER3 in drug resistance, the HER3-targeted therapies that are conducted in preclinical and clinical trials, and some emerging molecules that could be used as future designed drugs for HER3, aiming to provide insights for future research and development of anticancer drugs targeting HER3.

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

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

SIBP-03, a novel anti-HER3 antibody, exerts antitumor effects and synergizes with EGFR- and HER2-targeted drugs

HER3 (human epidermal growth factor receptor 3) acts through heterodimerization with EGFR (epidermal growth factor receptor) or HER2 to play an essential role in activating phosphoinositide 3-kinase (PI3K) and AKT signaling-a crucial pathway that promotes tumor cell survival. HER3 is a promising target for cancer therapy, and several HER3-directed antibodies have already entered into clinical trials. In this study we characterized a novel anti-HER3 monoclonal antibody, SIBP-03. SIBP-03 (0.01-10 μg/mL) specifically and concentration-dependently blocked both neuregulin (NRG)-dependent and -independent HER3 activation, attenuated HER3-mediated downstream signaling and inhibited cell proliferation. This antitumor activity was dependent, at least in part, on SIBP-03-induced, cell-mediated cytotoxicity and cellular phagocytosis. Importantly, SIBP-03 enhanced the antitumor activity of EGFR- or HER2-targeted drugs (cetuximab or trastuzumab) in vitro and in vivo. The mechanisms underlying this synergy involve increased inhibition of HER3-mediated downstream signaling. Collectively, these results demonstrated that SIBP-03, which is currently undergoing a Phase I clinical trial in China, may offer a new treatment option for patients with cancers harboring activated HER3, particularly as part of a combinational therapeutic strategy.

Synthesis of novel pyrimido[4,5-b]quinoline derivatives as dual EGFR/HER2 inhibitors as anticancer agents

A series of novel N-aryl-5-aryl-6,7,8,9-tetrahydropyrimido[4,5-b]quinolin-4-amines 4a-4l was synthesized as potential anticancer agents through Dimroth rearrangement reaction of intermediates 3a-3c. Pyrimido[4,5-b]quinolines 4a-4l showed promising activity against the Michigan Cancer Foundation-7 (MCF-7) cell line, compared with lapatinib as the reference drug. Compounds 4d, 4h, 4i, and 4l demonstrated higher cytotoxic activity than lapatinib, with IC50 values of 2.67, 6.82, 4.31, and 1.62 µM, respectively. Compounds 4d, 4i, and 4l showed promising epidermal growth factor receptor (EGFR) inhibition with IC50 values of 0.065, 0.116, and 0.052 µM, respectively. These compounds were subjected to human epidermal growth factor receptor 2 (HER2) inhibition and showed IC50 values of 0.09, 0.164, and 0.055 µM, respectively. Compounds 4d, 4i, and 4l are good candidates as dual EGFR/HER2 inhibitors. The most active compound, 4l, was subjected to cell-cycle analysis and induced cell-cycle arrest at the S phase. Compound 4l induced apoptosis 60-fold compared with control untreated MCF-7 cells. 4l can inhibit cancer metastasis. It reduced MCF-7 cell infiltration and metastasis by 45% compared with control untreated cells.

Covalent inhibition of epidermal growth factor receptor using a long-lived iridium(III)-afatinib probe

The overexpression and overactivation of epidermal growth factor receptor (EGFR) are frequently observed in human cancers, including squamous cell carcinoma and adenocarcinoma. In this study, a covalent EGFR probe was developed by conjugating afatinib to an iridium(III) scaffold. Complex 1 showed enhanced luminescence in living epidermoid squamous carcinoma A431 cells compared to other cell lines, via engaging EGFR as confirmed via CETSA and knockdown experiments. Moreover, complex 1 inhibited downstream targets of EGFR in cellulo with repression persisting after removal of the complex, indicating an irreversible mode of inhibition. Finally, complex 1 showed potent antiproliferative activity against A431 cells with comparable potency to afatinib alone. To our knowledge, complex 1 is the first EGFR covalent inhibitor based on an iridium scaffold reported in the literature, with the potential to be further explored as a theranostic agent in the future.

Unveiling promising breast cancer biomarkers: an integrative approach combining bioinformatics analysis and experimental verification

BACKGROUND

Breast cancer remains a significant health challenge worldwide, necessitating the identification of reliable biomarkers for early detection, accurate prognosis, and targeted therapy.

MATERIALS AND METHODS

Breast cancer RNA expression data from the TCGA database were analyzed to identify differentially expressed genes (DEGs). The top 500 up-regulated DEGs were selected for further investigation using random forest analysis to identify important genes. These genes were evaluated based on their potential as diagnostic biomarkers, their overexpression in breast cancer tissues, and their low median expression in normal female tissues. Various validation methods, including online tools and quantitative Real-Time PCR (qRT-PCR), were used to confirm the potential of the identified genes as breast cancer biomarkers.

RESULTS

The study identified four overexpressed genes (CACNG4, PKMYT1, EPYC, and CHRNA6) among 100 genes with higher importance scores. qRT-PCR analysis confirmed the significant upregulation of these genes in breast cancer patients compared to normal samples.

CONCLUSIONS

These findings suggest that CACNG4, PKMYT1, EPYC, and CHRNA6 may serve as valuable biomarkers for breast cancer diagnosis, and PKMYT1 may also have prognostic significance. Furthermore, CACNG4, CHRNA6, and PKMYT1 show promise as potential therapeutic targets. These findings have the potential to advance diagnostic methods and therapeutic approaches for breast cancer.

HER2GAN: Overcome the Scarcity of HER2 Breast Cancer Dataset Based on Transfer Learning and GAN Model

INTRODUCTION

Immunohistochemistry (IHC) is crucial for breast cancer diagnosis, classification, and individualized treatment. IHC is used to measure the levels of expression of hormone receptors (estrogen and progesterone receptors), human epidermal growth factor receptor 2 (HER2), and other biomarkers, which are used to make treatment decisions and predict how well a patient will do. The evaluation of the breast cancer score on IHC slides, taking into account structural and morphological features as well as a scarcity of relevant data, is one of the most important issues in the IHC debate. Several recent studies have utilized machine learning and deep learning techniques to resolve these issues.

MATERIALS AND METHODS

This paper introduces a new approach for addressing the issue based on supervised deep learning. A GAN-based model is proposed for generating high-quality HER2 images and identifying and classifying HER2 levels. Using transfer learning methodologies, the original and generated images were evaluated.

RESULTS AND CONCLUSION

All of the models have been trained and evaluated using publicly accessible and private data sets, respectively. The InceptionV3 and InceptionResNetV2 models achieved a high accuracy of 93% with the combined generated and original images used for training and testing, demonstrating the exceptional quality of the details in the synthesized images.

Advances in HER2-Targeted Treatment for Advanced/Metastatic Urothelial Carcinoma

Urothelial carcinoma (UC) represents a common malignancy of the urinary system that can involve the kidneys, ureter, bladder, and urethra. Advanced/metastatic UC (mUC) tends to have a poor prognosis. UC ranks third in terms of human epidermal growth factor receptor 2 (HER2) overexpression among all tumors. However, multiple studies found that, unlike breast cancer, variable degrees of HER2 positivity and poor consistency between HER2 protein overexpression and gene amplification have been found. Trials involving trastuzumab, pertuzumab, lapatinib, afatinib, and neratinib have failed to prove their beneficial effect in patients with HER2-positive mUC, and a clinical trial on T-DM1 (trastuzumab emtansine) was terminated prematurely because of the adverse reactions. However, a phase II trial showed that RC48-ADC was effective. In this review, we provided an in-depth overview of the advances in the research regarding HER2-targeted therapy and the role of HER2 in mUC. Furthermore, we also discussed the prospects of potential strategies aimed at overcoming anti-HER2 resistance, and summarize the novel anti-HER2 approaches for the management of mUC used in recent clinical trials.

Updated Clinical Perspectives and Challenges of Chimeric Antigen Receptor-T Cell Therapy in Colorectal Cancer and Invasive Breast Cancer

In recent years, the incidence of colorectal cancer (CRC) and breast cancer (BC) has increased worldwide and caused a higher mortality rate due to the lack of selective anti-tumor therapies. Current chemotherapies and surgical interventions are significantly preferred modalities to treat CRC or BC in advanced stages but the prognosis for patients with advanced CRC and BC remains dismal. The immunotherapy technique of chimeric antigen receptor (CAR)-T cells has resulted in significant clinical outcomes when treating hematologic malignancies. The novel CAR-T therapy target antigens include GUCY2C, CLEC14A, CD26, TEM8/ANTXR1, PDPN, PTK7, PODXL, CD44, CD19, CD20, CD22, BCMA, GD2, Mesothelin, TAG-72, CEA, EGFR, B7H3, HER2, IL13Ra2, MUC1, EpCAM, PSMA, PSCA, NKG2D. The significant aim of this review is to explore the recently updated information pertinent to several novel targets of CAR-T for CRC, and BC. We vividly described the challenges of CAR-T therapies when treating CRC or BC. The immunosuppressive microenvironment of solid tumors, the shortage of tumor-specific antigens, and post-treatment side effects are the major hindrances to promoting the development of CAR-T cells. Several clinical trials related to CAR-T immunotherapy against CRC or BC have already been in progress. This review benefits academicians, clinicians, and clinical oncologists to explore more about the novel CAR-T targets and overcome the challenges during this therapy.

Management of patients with HER2-positive metastatic breast cancer after trastuzumab deruxtecan failure

The current treatment of patients with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer (ABC) has been greatly impacted in the past decade by the introduction of antibody-drug conjugates (ADCs), which represent a relatively novel therapeutic class with the peculiar ability to deliver otherwise overtly toxic chemotherapeutics to tumor sites by exploiting the specificities of monoclonal antibodies. Indeed, drug engineering refinements in ADC design, such as through the introduction of cleavable linkers and hydrophobic payloads, resulted in improved patient outcomes in recent years. Two different ADCs, namely trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd), have already entered clinical practice for the treatment of HER2-positive ABC. In this scenario, T-DXd has shown to portend better survival outcomes compared to T-DM1, while leaving a large unsought area of unmet medical need upon T-DXd failure. Treatment decision and benefit of cancer drugs following T-DXd still represent an area of clinical controversy, where a preclinical investigation and clinical development should be prioritized. As the pace of innovation is currently accelerating, and with novel ADC formulations advancing in early-phase clinical trials, the whole BC field is changing at an unprecedented rate, with potential broadenings of therapeutic indications. In this review, we present the clinical landscape of HER2-positive advanced BC and discuss our vision on how to tackle T-DXd resistance, providing a perspective on the priority areas of the cancer research in this setting.

A phase I trial of the pan-ERBB inhibitor neratinib combined with the MEK inhibitor trametinib in patients with advanced cancer with EGFR mutation/amplification, HER2 mutation/amplification, HER3/4 mutation or KRAS mutation

PURPOSE

Aberrant alterations of ERBB receptor tyrosine kinases lead to tumorigenesis. Single agent therapy targeting EGFR or HER2 has shown clinical successes, but drug resistance often develops due to aberrant or compensatory mechanisms. Herein, we sought to determine the feasibility and safety of neratinib and trametinib in patients with EGFR mutation/amplification, HER2 mutation/amplification, HER3/4 mutation and KRAS mutation.

METHODS

Patients with actionable somatic mutations or amplifications in ERBB genes or actionable KRAS mutations were enrolled to receive neratinib and trametinib in this phase I dose escalation trial. The primary endpoint was determination of the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT). Secondary endpoints included pharmacokinetic analysis and preliminary anti-tumor efficacy.

RESULTS

Twenty patients were enrolled with a median age of 50.5 years and a median of 3 lines of prior therapy. Grade 3 treatment-related toxicities included: diarrhea (25%), vomiting (10%), nausea (5%), fatigue (5%) and malaise (5%). The MTD was dose level (DL) minus 1 (neratinib 160 mg daily with trametinib 1 mg, 5 days on and 2 days off) given 2 DLTs of grade 3 diarrhea in DL1 (neratinib 160 mg daily with trametinib 1 mg daily). The treatment-related toxicities of DL1 included: diarrhea (100%), nausea (55.6%) and rash (55.6%). Pharmacokinetic data showed trametinib clearance was significantly reduced leading to high drug exposures of trametinib. Two patients achieved stable disease (SD) ≥ 4 months.

CONCLUSION

Neratinib and trametinib combination was toxic and had limited clinical efficacy. This may be due to suboptimal drug dosing given drug-drug interactions.

TRIAL REGISTRATION ID

NCT03065387.

Comparison of breast cancer HER-2 receptor testing with immunohistochemistry and in situ hybridization

PURPOSE

Human epidermal growth factor receptor-2 (HER2) status can be tested with immunohistochemistry (IHC) and in situ hybridization (ISH). The 2018 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) HER2 testing guidelines suggest initial HER2 testing using IHC and further testing IHC equivocal cases with ISH. However, many institutions perform both IHC and ISH on the same specimen. This study aims to analyze the concordance between HER2 IHC and ISH in order to evaluate the benefit of repeating HER2 testing on the same breast cancer specimens.

METHOD

Patients diagnosed with invasive breast cancer through BreastScreen NSW Sydney West program between January 2018 and December 2020 were identified and their HER2 IHC and HER2 ISH results on core needle biopsy (CNB) and surgical excisions (SE) were retrospectively collected. Specimens with both IHC and ISH results were then analyzed for agreement and concordance using unweighted kappa values. Equivocal IHC (2+) cases were excluded from concordance analysis.

RESULTS

Overall, there were 240 invasive breast cancer specimens (CNB and SE) with both IHC and ISH recorded. Concordance between HER2 IHC and ISH was 100% (95% CI: 96.2-100%; κ = 1.00 (P < 0.001)). Of the IHC equivocal cases (n = 146), 94.5% were ISH negative.

CONCLUSION

There was perfect positive concordance and agreement between non-equivocal IHC and ISH results. This reinforces that IHC alone can be utilized reliably for testing HER2 status of non-equivocal cases consistent with the 2018 ASCO/CAP guidelines.

Her2low breast cancer. New opportunities and challenges

Background. Breast cancer is an increasingly prevalent cancer pathology. In developed countries, breast cancer hits almost every eighth woman and ranks first in the incidence of patients with malignant tumors. The success of breast cancer therapy is apparently connected with the effectiveness of a strategy of impact on typical breast cancer targets, such as estrogen and progesterone receptors, HER2/neu oncoprotein. Implementation of modern achievements of fundamental science into routine clinical practice will allow the prognosis of patients with breast cancer at both earlier and later stages (in cases of the metastatic lesion) to be improved. Purpose. To review modern literature sources that cover biological and clinical relevance of expanding molecular genetic classification of breast cancer for the purpose of singling out additional clinically significant breast cancer subtypes with special emphasis on HER2-low-positive tumors. Materials and methods. The literature search was performed manually by the keywords (breast cancer, HER2-low-positive breast cancer), and also literature sources from evidential databases PubMed, and Web of Science were reviewed. The data from meta-analyses, randomized trials, systematic reviews, cohort trials, and the data of fundamental works were taken into consideration. 41 literature sources were analyzed in total. We opted for the sources which were published over the last ten years. Results. Breast cancer is a heterogeneous disease. Overexpression of the HER2 receptor is peculiar to 15–20% of breast tumors, usually due to amplification of the ERBB2 gene. Taking into account that the ERBB2 gene is a very powerful proto-oncogene, tumors with such phenotype are characterized by aggressive course and unfavorable prognosis. Starting from the 1990s, the development of target drugs aimed at the blockade of HER2 receptors beginning from monoclonal antibodies – trastuzumab, later – pertuzumab, tyrosine kinase inhibitors (lapatinib, neratinib, tucatinib) and the new class of antitumor drugs – conjugates of a monoclonal antibody with a cytostatic drug (trastuzumab emtansine, trastuzumab deruxtecan, trastuzumab duocarmazine) and their implementation into clinical practice changed the course and the prognosis of the patients with HER2-positive breast cancer. In opposition to earlier clinical trials, the results of the more modern ones demonstrate the clinical effectiveness of new antitumor drugs such as conjugates of HER2 monoclonal antibody with a cytostatic drug (trastuzumab deruxtekan, trastuzumab duokarmazine) not only in patients with HER2-positive breast cancer but also in some patients with metastatic breast cancer with low HER2 expression. In order to determine the patients who may potentially benefit from the new target drugs among the patients with HER2-negative breast cancer, a new concept of HER2/neu-low breast cancer has been suggested, which is used for the selection of patients in modern clinical trials, and in the measurable future it will be used in routine clinical practice. Conclusions. Today’s scientific data confirm biological and clinical relevance of expanding molecular genetic classification of breast cancer for the purpose of singling out additional clinically significant breast cancer subtypes with special emphasis on HER2-low-positive tumors. The development of a new class of antitumor drugs, namely conjugates of HER2 monoclonal antibody with a cytostatic drug (trastuzumab deruxtekan, trastuzumab duokarmazine) gives new therapeutic possibilities for patients with breast cancer, and also for patients with other types of malignant tumors.

Biomarkers and translational research approaches in breast cancer—an update

Diagnosis and decision-making in the treatment of breast cancer patients is vastly dependent on the exploration of biomarkers. Estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 are long-standing biomarkers, which determine the breast cancer subtype. In current practice, gene expression analyses further define the molecular breast cancer subtype and give additional information on disease characteristics. Prognostic biomarkers provide information regarding recurrence risk and survival. Predictive biomarkers, such as programmed cell death ligand 1 expression, are tools for identifying patients who can benefit from specific therapy regimens in order to choose the best treatment option for the patient. While some biomarkers are affordable and readily available, others remain technically complex to access. Translational research builds the bridge from discovering novel biomarkers in preclinical studies to testing their application utility in the clinical setting. Integrating translational studies into clinical trials is therefore essential to find novel and reliable biomarkers for an optimal personalized treatment approach for patients with breast cancer.