HER2 therapy: molecular mechanisms of trastuzumab resistance

Trastuzumab, a monoclonal anti-HER2 antibody modulates cytotoxicity against cholangiocarcinoma via multiple mechanisms

Cholangiocarcinoma (CCA) is an aggressive and fatal cancer. The prognosis is very poor and no optimal chemotherapy has been established. Human epidermal growth factor receptor 2 (HER2, neu, and erbB2) is highly-expressed in breast cancer and is expressed in many other tumors but poorly expressed in CCA. The anti-HER2 antibody, trastuzumab, has been used for the treatment of HER2-positive breast and gastric cancer. In this study, we examined the surface expression of HER2 on seven Thai liver-fluke-associated CCA cell lines by flow cytometry, and found all of these CCA cells were weakly positive for HER2. MTT assay revealed that trastuzumab directly suppressed the growth of CCA. By using FcR-bearing recombinant Jurkat T-cell-expressing firefly luciferase gene under the control of NFAT response elements, we defined the activities of antibody-dependent cytotoxicity (ADCC) and antibody-dependent cell phagocytosis (ADCP). ADCC was confirmed by using expanded NK cells. ADCP was confirmed by using mouse peritoneal macrophages and human monocyte-derived macrophages as effector cells. Rabbit serum was administered to test the complement-dependent cytotoxicity (CDC) activity of trastuzumab. Finally, we evaluated the efficacy of trastuzumab in in vivo patient-derived cell xenograft and patient-derived xenograft (PDX) models. Our results showed that a distinct population of CCA (liver-fluke-associated CCA) expressed HER2. Trastuzumab demonstrated a potent inhibitory effect on even HER2 weakly positive CCA both in vitro and in vivo via multiple mechanisms. Thus, HER2 is a promising target in anti-CCA therapy, and trastuzumab can be considered a promising antibody immunotherapy agent for the treatment of CCA.

Unveiling Alterations of Epigenetic Modifications and Chromatin Architecture Leading to Lipid Metabolic Reprogramming during the Evolutionary Trastuzumab Adaptation of HER2-Positive Breast Cancer

Secondary trastuzumab resistance represents an evolutionary adaptation of HER2-positive breast cancer during anti-HER2 treatment. Most current studies have tended to prioritize HER2 and its associated signaling pathways, often overlooking broader but seemingly less relevant cellular processes, along with their associated genetic and epigenetic mechanisms. Here, transcriptome data is not only characterized but also examined epigenomic and 3D genome architecture information in both trastuzumab-sensitive and secondary-resistant breast cancer cells. The findings reveal that the global metabolic reprogramming associated with trastuzumab resistance may stem from genome-wide alterations in both histone modifications and chromatin structure. Specifically, the transcriptional activities of key genes involved in lipid metabolism appear to be regulated by variant promoter H3K27me3 and H3K4me3 modifications, as well as promoter-enhancer interactions. These discoveries offer valuable insights into how cancer cells adapt to anti-tumor drugs and have the potential to impact future diagnostic and treatment strategies.

Development and evaluation of a human CD47/HER2 bispecific antibody for Trastuzumab-resistant breast cancer immunotherapy

The treatment for trastuzumab-resistant breast cancer (BC) remains a challenge in clinical settings. It was known that CD47 is preferentially upregulated in HER2+ BC cells, which is correlated with drug resistance to trastuzumab. Here, we developed a novel anti-CD47/HER2 bispecific antibody (BsAb) against trastuzumab-resistant BC, named IMM2902. IMM2902 demonstrated high binding affinity, blocking activity, antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and internalization degradation effects against both trastuzumab-sensitive and trastuzumab-resistant BC cells in vitro. The in vivo experimental data indicated that IMM2902 was more effective than their respective controls in inhibiting tumor growth in a trastuzumab-sensitive BT474 mouse model, a trastuzumab-resistant HCC1954 mouse model, two trastuzumab-resistant patient-derived xenograft (PDX) mouse models and a cord blood (CB)-humanized HCC1954 mouse model. Through spatial transcriptome assays, multiplex immunofluorescence (mIFC) and in vitro assays, our findings provided evidence that IMM2902 effectively stimulates macrophages to generate C-X-C motif chemokine ligand (CXCL) 9 and CXCL10, thereby facilitating the recruitment of T cells and NK cells to the tumor site. Moreover, IMM2902 demonstrated a high safety profile regarding anemia and non-specific cytokines release. Collectively, our results highlighted a novel therapeutic approach for the treatment of HER2+ BCs and this approach exhibits significant anti-tumor efficacy without causing off-target toxicity in trastuzumab-resistant BC cells.

Conformational diversity and protein-protein interfaces in drug repurposing in Ras signaling pathway

We focus on drug repurposing in the Ras signaling pathway, considering structural similarities of protein-protein interfaces. The interfaces formed by physically interacting proteins are found from PDB if available and via PRISM (PRotein Interaction by Structural Matching) otherwise. The structural coverage of these interactions has been increased from 21 to 92% using PRISM. Multiple conformations of each protein are used to include protein dynamics and diversity. Next, we find FDA-approved drugs bound to structurally similar protein-protein interfaces. The results suggest that HIV protease inhibitors tipranavir, indinavir, and saquinavir may bind to EGFR and ERBB3/HER3 interface. Tipranavir and indinavir may also bind to EGFR and ERBB2/HER2 interface. Additionally, a drug used in Alzheimer's disease can bind to RAF1 and BRAF interface. Hence, we propose a methodology to find drugs to be potentially used for cancer using a dataset of structurally similar protein-protein interface clusters rather than pockets in a systematic way.

Enhanced therapeutic action of Trastuzumab loaded ZnxMn1-xFe2O4 nanoparticles using a pre-treatment step for hyperthermia treatment of HER2+ breast cancer

In this study, Ferrites (Fe3O4, MnFe2O4, ZnFe2O4) and different stoichiometric ratios of ZnxMn1-xFe2O4 (x = 0.2, 0.4, 0.6, and 0.8) nanoparticles (<15 nm) were synthesized by microwave-assisted method and optimised for hyperthermia studies. The selection of the optimised variant of ferrite i.e. Zn0.4Mn0.6Fe2O4 was found to be the best variant based on VSM (38.14 emu g-1) hyperthermia-based temperature rise (maximum ΔT of 38 °C), SAR and ILP values. Trastuzumab, which is known to bind with HER2 receptors of breast cancer was chemically tethered onto Zn0.4Mn0.6Fe2O4 nanoparticles through EDC/NHS coupling with a loading efficiency of 80%. The attached Trastuzumab aided during the pre-treatment step by aiding in the internalisation of Zn0.4Mn0.6Fe2O4 nanoparticles, with cellular uptake of 11% in SK-BR-3 (cancerous HER2+) cells compared to ∼5% for MDA-MB-231 (cancerous HER2-) and RPE-1 (non-cancerous) cells. In the presence of a hyperthermia trigger for 15 mins, ZnxMn1-xFe2O4 -Trastuzumab formulation had a maximum therapeutic effect by reducing the SK-BR-3 cell viability to 14% without adversely affecting the RPE-1 cells. The mechanism of ZnxMn1-xFe2O4-Trastuzumab combination was examined using an internalisation study, MTT-based viability, proliferation study, and ROS generation assay. By utilizing both Trastuzumab and hyperthermia, we achieve their synergistic anticancer properties while minimizing the drug requirement and reducing any effect on non-cancerous cells.

Molecular imprinting of miR-559 on a peptide-immobilized poly L-DOPA/silica core-shell and in vitro investigating its effects on HER2-positive breast cancer cells

In a significant percentage of breast cancers, increased expression of the HER2 receptor is seen and is associated with the spread and worsening of the disease. This research aims to investigate the effect of miR-559 (which targets HER2 mRNA) on SKBR3 breast cancer cells and the possibility of their effective delivery with polymeric nanoparticles and tumor-targeting peptides. L-DOPA monomers were polymerized on the surface of silica nanoparticles in the presence of miR-559 (as a molecular template for molecular imprinting) then an anti-HER2 peptide coupled to the surface of these polymeric nanocomposites (miR-NC-NL2), and the effects of this construct against a HER2-positive breast cancer cells (SKBR3 cells) investigated in vitro conditions. The results showed that miR-NC-NL2 is selective for HER2-positive cells and delivers the miR-559 to them in a targeted manner. miR-NC-NL2 decreased the proliferation of SKBR3 cells and reduced the expression and production of HER2 protein in these cells. Effective and targeted delivery of miR-559 to HER2-positive cancer cells by the miR-NC-NL2 promises the therapeutic potential of this nascent structure based on its inhibitory effect on cancer growth and progression. Of course, animal experiments require a better understanding of this structure's anti-tumor effects.

Plasma microRNA-195, -34c, and - 1246 as novel biomarkers for the diagnosis of trastuzumab-resistant HER2-positive breast cancer patients

Recently, miRNAs have been regarded as potential candidates for mediating therapeutic functions by targeting genes related to drug response. In this study, we suggested that plasma miRNAs may be correlated with response to trastuzumab in HER2-positive breast cancer patients. To determine whether miR-195, miR-23b-3p, miR-1246, and miR-34c-3p are involved in trastuzumab resistance, we screened their expressions in the BT-474 cell line, which was followed by plasma analysis from 20 trastuzumab-resistant HER2-positive breast cancer patients and 20 nonresistance subjects. Then, TargetScan, Pictar, and miRDB were applied to find the possible targets of the selected miRNAs. In addition, the expression status of admitted targets was evaluated. Our results showed that in resistant BT-474 cells, miR-1246, and miR-23b-3p were significantly upregulated, and miR-195-5p and miR-34c-3p were downregulated. In plasma analysis, we found miR-195-5p, miR-34c-3p, and miR-1246 meaningfully diminished in the resistant group, while the expression of miR-23b-3p was not statistically different. The expression levels of confirmed targets by qRT-PCR showed that the expression of RAF1, AKT3, c-MET, CCND1, PHLPP2, MYB, MAP2K1, and PTEN was significantly upregulated, while the expression of CCNG2 was significantly downregulated. The networks of miRNAs with their confirmed targets improved comprehension of miRNA-mediated therapeutic responses to trastuzumab and might be proposed for more characterization of miRNA functions. Moreover, these data indicated that miR-195-5p, miR-34c-3p, and miR-1246 could be possible biomarkers for prognosis and early detection of the trastuzumab-resistant group from the sensitive group of HER2-positive breast cancer patients.

Combination of Chemotherapy and Mild Hyperthermia Using Targeted Nanoparticles: A Potential Treatment Modality for Breast Cancer

Despite the clinical benefits that chemotherapeutics has had on the treatment of breast cancer, drug resistance remains one of the main obstacles to curative cancer therapy. Nanomedicines allow therapeutics to be more targeted and effective, resulting in enhanced treatment success, reduced side effects, and the possibility of minimising drug resistance by the co-delivery of therapeutic agents. Porous silicon nanoparticles (pSiNPs) have been established as efficient vectors for drug delivery. Their high surface area makes them an ideal carrier for the administration of multiple therapeutics, providing the means to apply multiple attacks to the tumour. Moreover, immobilising targeting ligands on the pSiNP surface helps direct them selectively to cancer cells, thereby reducing harm to normal tissues. Here, we engineered breast cancer-targeted pSiNPs co-loaded with an anticancer drug and gold nanoclusters (AuNCs). AuNCs have the capacity to induce hyperthermia when exposed to a radiofrequency field. Using monolayer and 3D cell cultures, we demonstrate that the cell-killing efficacy of combined hyperthermia and chemotherapy via targeted pSiNPs is 1.5-fold higher than applying monotherapy and 3.5-fold higher compared to using a nontargeted system with combined therapeutics. The results not only demonstrate targeted pSiNPs as a successful nanocarrier for combination therapy but also confirm it as a versatile platform with the potential to be used for personalised medicine.

A cell-based subtractive panning strategy for selection of conformation-specific single-chain variable-fragment (scFv) against dimerization domain of EGFR

BACKGROUND AND OBJECTIVE

Overexpression of EGFR, a member of the ErbB receptor family, has been observed in several cancers and causes resistance to therapeutic antibodies, such as Herceptin. In this study, we produced a recombinant single-chain variable fragment (scFv) antibody against the EGFR dimerization domain.

METHODS

The recombinant scFv was generated using a cell-based subtractive panning strategy. Subtractive panning was performed on a genetically engineered, VERO/EGFR, cells as well as a triple-negative breast cancer, MDA-MB-468, cells. Phage cell-ELISA was used to monitor the binding of the selected scFvs to the dimerization domain of EGFR. Inhibition of EGFR and HER2 dimerization by the produced scFvs were finally evaluated using the dimerization inhibition test and the expression of apoptosis-related genes were measured using the quantitative RT-PCR.

RESULTS

PCR fingerprinting results showed a uniform digestion pattern following the third round of panning that confirmed the success of subtractive panning. Moreover, cell-ELISA validated the reactivity of the produced scFvs to EGFR following stimulation with EGF. Dimerization inhibition test showed the capacity of the scFvs to inhibit EGFR and HER2 dimerization. Investigation of apoptosis-related genes showed that treatment with the scFv antibody caused increased Bax and decreased Bcl2 expression.

CONCLUSIONS

Directed HER2 targeting was shown to be effective enough to block the functional domain of the cell receptor and its intracellular signaling pathway. The subtractive panning strategy used in this study could control the process of directed selection of specific antibodies against the dimerization domain of EGFR. Selected antibodies might then be functionally tested for antitumor effects in both in vitro and in vivo studies.

Coupling substrate-trapping with proximity-labeling to identify protein tyrosine phosphatase PTP1B signaling networks

The ability to define functional interactions between enzymes and their substrates is crucial for understanding biological control mechanisms; however, such methods face challenges in the transient nature and low stoichiometry of enzyme-substrate interactions. Now, we have developed an optimized strategy that couples substrate-trapping mutagenesis to proximity-labeling mass spectrometry for quantitative analysis of protein complexes involving the protein tyrosine phosphatase PTP1B. This methodology represents a significant shift from classical schemes; it is capable of being performed at near-endogenous expression levels and increasing stoichiometry of target enrichment without a requirement for stimulation of supraphysiological tyrosine phosphorylation levels or maintenance of substrate complexes during lysis and enrichment procedures. Advantages of this new approach are illustrated through application to PTP1B interaction networks in models of HER2-positive and Herceptin-resistant breast cancer. We have demonstrated that inhibitors of PTP1B significantly reduced proliferation and viability in cell-based models of acquired and de novo Herceptin resistance in HER2-positive breast cancer. Using differential analysis, comparing substrate-trapping to wild-type PTP1B, we have identified multiple unreported protein targets of PTP1B with established links to HER2-induced signaling and provided internal validation of method specificity through overlap with previously identified substrate candidates. Overall, this versatile approach can be readily integrated with evolving proximity-labeling platforms (TurboID, BioID2, etc.), and is broadly applicable across all PTP family members for the identification of conditional substrate specificities and signaling nodes in models of human disease.

Biotransformation of Trastuzumab and Pertuzumab in Breast Cancer Patients Assessed by Affinity Enrichment and Ion-Exchange Chromatography

Therapeutic proteins (TPs) are known to be heterogeneous due to modifications that occur during the production process and storage. Modifications may also occur in TPs after their administration to patients due to in vivo biotransformation. Ligand binding assays, which are widely used in the bioanalysis of TPs in body fluids, are typically unable to distinguish such modifications. Liquid chromatography coupled to mass spectrometry is being increasingly used to study modifications in TPs, but its use to study in vivo biotransformation has been limited until now. We present a novel approach that combines affinity enrichment using Affimer reagents with ion-exchange chromatography (IEX) to analyze charge variants of the TPs trastuzumab and pertuzumab in plasma of patients undergoing therapy for HER2-positive breast cancer. Affimer reagents were immobilized via engineered Cys tags to maleimide beads, and the TPs were eluted under acidic conditions followed by rapid neutralization. The enriched TPs were analyzed by cation-exchange chromatography (IEX) using pH-gradient elution, resulting in the separation of about 20 charge variants for trastuzumab and about five charge variants for pertuzumab. A comparison between in vitro stressed TPs spiked into plasma, and TPs enriched from patient plasma showed that the observed profiles were highly similar. This indicates that in vitro stress testing in plasma can mimic the situation in patient plasma, as far as the generation of charge variants is concerned. SIGNIFICANCE STATEMENT: This research attempts to elucidate the modifications that occur in therapeutic proteins (TPs) after they have been administered to patients. This is important because there is little knowledge about the fate of TPs in this regard, and certain modifications could affect their efficiency. Our results show that the modifications discovered are most likely due to a chemical process and are not patient specific.

Gold nanoparticles-based photothermal therapy for breast cancer

AuNPs-mediated photothermal therapy (PTT) is gaining popularity in both laboratory research and medical applications. It has proven clear advantages in breast cancer therapy over conventional thermal ablation because of its easily-tuned features of irradiation light with inside hyperthermia ability. Notwithstanding this significant progress, the therapeutic potential of AuNPs-mediated PTT in cancer treatments is still impeded by several challenges, including inherent non-specificity, low photothermal conversion effectiveness, and the limitation of excitation light tissue penetration. Given the rapid progress of AuNPs-mediated PTT, we present a comprehensive overview of significant breakthroughs in the recent advancements of AuNPs for PTT, focusing on breast cancer cells. With the improvement of chemical synthesis technology, AuNPs of various sizes and shapes with desired properties can be synthesized, allowing breast cancer targeting and treatment. In this study, we summarized the different sizes and features of four major types of AuNPs in this review: Au nanospheres, Au nanocages, Au nanoshells, and Au nanorods, and explored their benefits and drawbacks in PTT. We also discussed the diagnostic, bioconjugation, targeting, and cellular uptake of AuNPs, which could improve the performance of AuNP-based PTT. Besides that, potential challenges and future developments of AuNP-mediated PTT for clinical applications are discussed. AuNP-mediated PTT is expected to become a highly promising avenue in cancer treatment in the near future.

Optimizing combination therapy in a murine model of HER2+ breast cancer

Human epidermal growth factor receptor 2 positive (HER2+) breast cancer is frequently treated with drugs that target the HER2 receptor, such as trastuzumab, in combination with chemotherapy, such as doxorubicin. However, an open problem in treatment design is to determine the therapeutic regimen that optimally combines these two treatments to yield optimal tumor control. Working with data quantifying temporal changes in tumor volume due to different trastuzumab and doxorubicin treatment protocols in a murine model of human HER2+ breast cancer, we propose a complete framework for model development, calibration, selection, and treatment optimization to find the optimal treatment protocol. Through different assumptions for the drug-tumor interactions, we propose ten different models to characterize the dynamic relationship between tumor volume and drug availability, as well as the drug-drug interaction. Using a Bayesian framework, each of these models are calibrated to the dataset and the model with the highest Bayesian information criterion weight is selected to represent the biological system. The selected model captures the inhibition of trastuzumab due to pre-treatment with doxorubicin, as well as the increase in doxorubicin efficacy due to pre-treatment with trastuzumab. We then apply optimal control theory (OCT) to this model to identify two optimal treatment protocols. In the first optimized protocol, we fix the maximum dosage for doxorubicin and trastuzumab to be the same as the maximum dose delivered experimentally, while trying to minimize tumor burden. Within this constraint, optimal control theory indicates the optimal regimen is to first deliver two doses of trastuzumab on days 35 and 36, followed by two doses of doxorubicin on days 37 and 38. This protocol predicts an additional 45% reduction in tumor burden compared to that achieved with the experimentally delivered regimen. In the second optimized protocol we fix the tumor control to be the same as that obtained experimentally, and attempt to reduce the doxorubicin dose. Within this constraint, the optimal regimen is the same as the first optimized protocol but uses only 43% of the doxorubicin dose used experimentally. This protocol predicts tumor control equivalent to that achieved experimentally. These results strongly suggest the utility of mathematical modeling and optimal control theory for identifying therapeutic regimens maximizing efficacy and minimizing toxicity.

Antibody-Drug Conjugates for the Treatment of HER2-Positive Breast Cancer

Human epidermal growth factor receptor 2 (HER2) receptor tyrosine kinase is overexpressed in 20-30% of breast cancers and is associated with poor prognosis and worse overall patient survival. Most women with HER2-positive breast cancer receive neoadjuvant chemotherapy plus HER2-targeted therapies. The development of HER2-directed therapeutics is an important advancement in targeting invasive breast cancer. Despite the efficacy of anti-HER2 monoclonal antibodies, they are still being combined with adjuvant chemotherapy to improve overall patient outcomes. Recently, significant progress has been made towards the development of a class of therapeutics known as antibody-drug conjugates (ADCs), which leverage the high specificity of HER2-targeted monoclonal antibodies with the potent cytotoxic effects of various small molecules, such as tubulin inhibitors and topoisomerase inhibitors. To date, two HER2-targeting ADCs have been approved by the FDA for the treatment of HER2-positive breast cancer: Ado-trastuzumab emtansine (T-DM1; Kadcyla®) and fam-trastuzumab deruxtecan-nxki (T-Dxd; Enhertu®). Kadcyla and Enhertu are approved for use as a second-line treatment after trastuzumab-taxane-based therapy in patients with HER2-positive breast cancer. The success of ADCs in the treatment of HER2-positive breast cancer provides novel therapeutic advancements in the management of the disease. In this review, we discuss the basic biology of HER2, its downstream signaling pathways, currently available anti-HER2 therapeutic modalities and their mechanisms of action, and the latest clinical and safety characteristics of ADCs used for the treatment of HER2-positive breast cancer.

Sabizabulin, a Potent Orally Bioavailable Colchicine Binding Site Agent, Suppresses HER2+ Breast Cancer and Metastasis

HER2+ breast cancer accounts for 15% of all breast cancer cases. Current frontline therapy for HER2+ metastatic breast cancer relies on targeted antibodies, trastuzumab and pertuzumab, combined with microtubule inhibitors in the taxane class (paclitaxel or docetaxel). It is well known that the clinical efficacy of taxanes is limited by the development of chemoresistance and hematological and neurotoxicities. The colchicine-binding site inhibitors (CBSIs) are a class of promising alternative agents to taxane therapy. Sabizabulin (formerly known as VERU-111) is a potent CBSI that overcomes P-gp-mediated taxane resistance, is orally bioavailable, and inhibits tumor growth and distant metastasis in triple negative breast cancer (TNBC). Herein, we demonstrate the efficacy of sabizabulin in HER2⁺ breast cancer. In vitro, sabizabulin inhibits the proliferation of HER2+ breast cancer cell lines with low nanomolar IC₅₀ values, inhibits clonogenicity, and induces apoptosis in a concentration-dependent manner. In vivo, sabizabulin inhibits breast tumor growth in the BT474 (ER+/PR+/HER2+) xenograft model and a HER2+ (ER-/PR-) metastatic patient-derived xenograft (PDX) model, HCI-12. We demonstrate that sabizabulin is a promising alternative agent to target tubulin in HER2+ breast cancer with similar anti-metastatic efficacy to paclitaxel, but with the advantage of oral bioavailability and lower toxicity than taxanes.

β-Escin overcomes trastuzumab resistance in HER2-positive breast cancer by targeting cancer stem-like features

Background

The emergence of de novo or intrinsic trastuzumab resistance is exceedingly high in breast cancer that is HER2 positive and correlates with an abundant cancer stem cell (CSC)-like population. We sought to examine the capacity of β-escin, an anti-inflammatory drug, to address trastuzumab resistance in HER2-positive breast cancer cells.

Methods

The effect of β-escin on trastuzumab-resistant and -sensitive cell lines in vitro was evaluated for apoptosis, expression of HER2 family members, and impact on CSC-like properties. An in vivo model of trastuzumab-resistant JIMT-1 was used to examine the efficacy and toxicity of β-escin.

Results

β-escin induced mitochondrial-mediated apoptosis accompanied by reactive oxygen species (ROS) production and increased active p18Bax fragmentation, leading to caspase-3/-7 activation. Attenuation of CSC-related features by β-escin challenge was accompanied by marked reductions in CD44^high/CD24^low stem-like cells and aldehyde dehydrogenase 1 (ALDH1) activity as well as hindrance of mammosphere formation. β-escin administration also significantly retarded tumor growth and angiogenesis in a trastuzumab-resistant JIMT-1 xenograft model via downregulation of CSC-associated markers and intracellular domain HER2. Importantly, β-escin selectively inhibited malignant cells and was less toxic to normal mammary cells, and no toxic effects were found in liver and kidney function in animals.

Conclusions

Taken together, our findings highlight β-escin as a promising candidate for the treatment of trastuzumab-resistant HER2-positive breast cancers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02713-9.

Quantifying the Effects of Combination Trastuzumab and Radiation Therapy in Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer

Background: Trastuzumab induces cell cycle arrest in HER2-overexpressing cells and demonstrates potential in radiosensitizing cancer cells. The purpose of this study is to quantify combination trastuzumab and radiotherapy to determine their synergy. Methods: In vitro, HER2+ cancer cells were treated with trastuzumab, radiation, or their combination, and imaged to evaluate treatment kinetics. In vivo, HER2+ tumor-bearing mice were treated with trastuzumab and radiation, and assessed longitudinally. An additional cohort was treated and sacrificed to quantify CD45, CD31, α-SMA, and hypoxia. Results: The interaction index revealed the additive effects of trastuzumab and radiation in vitro in HER2+ cell lines. Furthermore, the results revealed significant differences in tumor response when treated with radiation (p < 0.001); however, no difference was seen in the combination groups when trastuzumab was added to radiotherapy (p = 0.56). Histology revealed increases in CD45 staining in tumors receiving trastuzumab (p < 0.05), indicating potential increases in immune infiltration. Conclusions: The in vitro results showed the additive effect of combination trastuzumab and radiotherapy. The in vivo results showed the potential to achieve similar efficacy of radiotherapy with a reduced dose when combined with trastuzumab. If trastuzumab and low-dose radiotherapy induce greater tumor kill than a higher dose of radiotherapy, combination therapy can achieve a similar reduction in tumor burden.

AB186 Inhibits Migration of Triple-Negative Breast Cancer Cells and Interacts with α-Tubulin

Breast cancer is one of the leading causes of cancer-related death among females worldwide. A major challenge is to develop innovative therapy in order to treat breast cancer subtypes resistant to current treatment. In the present study, we examined the effects of two Troglitazone derivatives Δ2-TGZ and AB186. Previous studies showed that both compounds induce apoptosis, nevertheless AB186 was a more potent agent. The kinetic of cellular events was investigated by real-time cell analysis system (RTCA) in MCF-7 (hormone dependent) and MDA-MB-231 (triple negative) breast cancer (TNBC) cells, followed by cell morphology analysis by immuno-localization. Both compounds induced a rapid modification of both impedance-based signals and cellular morphology. This process was associated with an inhibition of cell migration measured by wound healing and transwell assays in TNBC MDA-MB-231 and Hs578T cells. In order to identify cytoplasmic targets of AB186, we performed surface plasmon resonance (SPR) and pull-down analyses. Subsequently, 6 cytoskeleton components were identified as potential targets. We further validated α-tubulin as one of the direct targets of AB186. In conclusion, our results suggested that AB186 could be promising to develop novel therapeutic strategies to treat aggressive forms of breast cancer such as TNBC.

Antibody-Incorporated Nanomedicines for Cancer Therapy

Antibody-based cancer therapy, one of the most significant therapeutic strategies, has achieved considerable success and progress over the past decades. Nevertheless, obstacles including limited tumor penetration, short circulation half-lives, undesired immunogenicity, and off-target side effects remain to be overcome for the antibody-based cancer treatment. Owing to the rapid development of nanotechnology, antibody-containing nanomedicines that have been extensively explored to overcome these obstacles have already demonstrated enhanced anticancer efficacy and clinical translation potential. This review intends to offer an overview of the advancements of antibody-incorporated nanoparticulate systems in cancer treatment, together with the nontrivial challenges faced by these next-generation nanomedicines. Diverse strategies of antibody immobilization, formats of antibodies, types of cancer-associated antigens, and anticancer mechanisms of antibody-containing nanomedicines are provided and discussed in this review, with an emphasis on the latest applications. The current limitations and future research directions on antibody-containing nanomedicines are also discussed from different perspectives to provide new insights into the construction of anticancer nanomedicines.

HER-2-Targeted Nanoparticles for Breast Cancer Diagnosis and Treatment

Human epidermal growth factor receptor-2 (HER-2) overexpressing breast cancer is a breast cancer subtype characterized by high aggressiveness, high frequency of brain metastases and poor prognosis. HER-2, a glycoprotein belonging to the ErbB receptor family, is overexpressed on the outer membrane of cancer cells and has been an important therapeutic target for the development of targeted drugs, such as the monoclonal antibodies trastuzumab and pertuzumab. These therapies have been available in clinics for more than twenty years. However, despite the initial enthusiasm, a major issue emerged limiting HER-2 targeted therapy efficacy, i.e., the evolution of drug resistance, which could be tackled by nanotechnology. The aim of this review is to provide a first critical update on the different types of HER-2-targeted nanoparticles that have been proposed in the literature in the last decade for therapeutic purposes. We focus on the different targeting strategies that have been explored, their relative outcomes and current limitations that still need to be improved. Then, we review the nanotools developed as diagnostic kits, focusing on the most recent techniques, which allow accurate quantification of HER-2 levels in tissues, with the aim of promoting more personalized medicinal approaches in patients.

ERBB2D16 Expression in HER2 Positive Gastric Cancer Is Associated With Resistance to Trastuzumab

The human epidermal growth factor receptor-2 (ERBB2; formerly HER2)isoform ERBB2ΔEx16 (ERBB2d16) was oncogenic by mediating epithelial-mesenchymal transition (EMT), immune evasion, and resistance cell death to the anti-HER2 (trastuzumab) therapy. However, its physiological implications in gastric cancer were unclear. In this study, we examined a total of 110 patients with either locally advanced or metastatic HER2⁺ gastric cancer for the expression of ERBB2d16 and EMT markers, and the infiltration of CD3⁺ T cells in tumor tissues, and evaluated their relevance with the responses to the standard chemotherapy plus trastuzumab according to the RECIST criteria. We found that the ERBB2d16 isoform was present at a relatively high level in about half of the tumor samples examined (53/110) and an elevated ERBB2d16/ERBB2 ratio was positively associated with the expression of high E-cadherin and low vimentin indicating EMT, and with poor CD3+ T cell infiltration and strong intratumoral expression of programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) as well as reduced diversity of T cell receptor clones. Moreover, the progression-free survival and overall survival of patients treated with trastuzumab were substantially shorter in those with a high ERBB2d16/ERBB2 ratio. In agreement, analysis by Cox proportional hazards models confirmed that high ERBB2d16 expression was a risk factor associated with an adverse prognosis. Thus, our data fit well with an oncogenic role of ERBB2d16 in gastric cancer by promoting EMT and immunosuppression. We also found that ERBB2d16 expression resists gastric cell death in patients treated with trustuzumab, and the ERBB2d16/ERBB2 ratio may serve as a novel prognostic maker for patients with gastric cancer that receive trastuzumab therapy.

Site-Selective Antibody-Drug Conjugation by a Proximity-Driven S to N Acyl Transfer Reaction on a Therapeutic Antibody

Immunoglobulin Gs (IgGs) contain many Lys and Cys residues, which results in an unwanted complex product mixture with conventional drug conjugation methods. We selectively acylated the ε-NH₂ of K248 on trastuzumab using an IgG Fc-binding peptide (FcBP) equipped with a 5-norbornene-2-carboxylic acid thioester (AbClick-1). AbClick-1 locates its thioester close to the ε-NH₂ of K248 while binding to trastuzumab. Consequently, the thioester underwent proximity-driven selective acylation of ε-NH₂ through an S to N acyl transfer reaction. Furthermore, N-tert-butyl maleimide accelerated the cross-linking reaction with an approximately 95% yield of the desired product by scavenging the byproduct (FcBP-SH). Only K248 was modified selectively with the 5-norbornene-2-carbonyl group, which was further modified by click reaction to afford an antibody-drug conjugate (ADC) with two drugs per antibody. The resulting ADCs showed remarkable in vitro and in vivo anticancer activity. Our results demonstrate that a thioester is a promising chemical entity for proximity-driven site-selective conjugation of antibodies.

Tyrosine Phosphatase PTPRO Deficiency in ERBB2-Positive Breast Cancer Contributes to Poor Prognosis and Lapatinib Resistance

Despite the initial benefit from treating ERBB2-positive breast cancer with tyrosine kinase inhibitor lapatinib, resistance develops inevitably. Since the expression of protein tyrosine phosphatase receptor-type O (PTPRO), a member of the R3 subfamily of receptor protein tyrosine phosphatases (PTPs), is inversely correlated with the aggressiveness of multiple malignancies, we decided to explore the correlation between PTPRO and lapatinib resistance in ERBB2-positive breast cancer. Results of immunohistochemical (IHC) staining and the correlation analysis between the expression levels of PTPRO and the clinicopathological parameters indicate that PTPRO is downregulated in cancer tissues as compared with normal tissues and negatively associated with differentiation, tumor size, tumor depth, as well as the expression of ERBB2 and Ki67. Results from Kaplan-Meier analyses indicate that lower expression of PTPRO is correlated with shorter relapse-free survival for patients with ERBB2-positive breast cancer, and multivariable Cox regression analysis found that PTPRO can potentially serve as an independent prognostic indicator for ERBB2-positive breast cancer. Results from both human breast cancer cells with PTPRO knockdown or overexpression and mouse embryonic fibroblasts (MEFs) which derived from Ptpro ^+/+ and Ptpro ^-/- mice with then stably transfected plasmid FUGW-Erbb2 consistently demonstrated the essentiality of PTPRO in the lapatinib-mediated anticancer process. Our findings suggest that PTPRO is not only able to serve as an independent prognostic indicator, but upregulating PTPRO can also reverse the lapatinib resistance of ERBB2-positive breast cancer.

Bispecific Antibodies for IFN-β Delivery to ErbB2+ Tumors

The main aim of our work was to create a full-length bispecific antibody (BsAb) as a vehicle for the targeted delivery of interferon-beta (IFN-β) to ErbB2+ tumor cells in the form of non-covalent complex of BsAb and IFN-β. Such a construct is a CrossMab-type BsAb, consisting of an ErbB2-recognizing trastuzumab moiety, a part of chimeric antibody to IFN-β, and human IgG1 Fc domain carrying knob-into-hole amino acid substitutions necessary for the proper assembly of bispecific molecules. The IFN-β- recognizing arm of BsAb not only forms a complex with the cytokine but neutralizes its activity, thus providing a mechanism to avoid the side effects of the systemic action of IFN-β by blocking IFN-β Interaction with cell receptors in the process of cytokine delivery to tumor sites. Enzyme sandwich immunoassay confirmed the ability of BsAb to bind to human IFN-β comparable to that of the parental chimeric mAb. The BsAb binds to the recombinant ErbB2 receptor, as well as to lysates of ErbB2+ tumor cell lines. The inhibition of the antiproliferative effect of IFN-β by BsAb (IC50 = 49,3 µg/mL) was demonstrated on the HT29 cell line. It can be proposed that the BsAb obtained can serve as a component of the immunocytokine complex for the delivery of IFN-β to ErbB2-associated tumor cells.

Dual-Modality PET-SPECT Image-Guided Pretargeting Delivery in HER2(+) Breast Cancer Models

Pretargeted drug delivery has been explored for decades as a promising approach in cancer therapy. An image-guided pretargeting strategy significantly enhances the intrinsic advantages of this approach since imaging the pretargeting step can be used for diagnostic purposes, while imaging of the drug delivery step can be utilized to evaluate drug distribution and assess therapeutic response. A trastuzumab (Tz)-based HER2 pretargeting component (Tz-TCO-[89Zr-DFO]) was developed by conjugating with trans-cyclooctene (TCO) bioorthogonal click chemistry functional groups and deferoxamine (DFO) to enable radiolabeling with a 89Zr PET tracer. The drug delivery component (HSA-DM1-Tt-[99mTc-HyNic]) was developed by conjugating human serum albumin (HSA) with mertansine (DM1), tetrazine (Tt) functional groups, and a HyNic chelator and radiolabeling with 99mTc. For ex vivo biodistribution studies, pretargeting and delivery components (without drug) were administered subsequently to mice bearing human HER2(+) breast cancer xenografts, and a high tumor uptake of Tz-TCO-[89Zr-DFO] (26.4% ID/g) and HSA-Tt-[99mTc-HyNic] (4.6% ID/g) was detected at 24 h postinjection. In vivo treatment studies were performed in the same HER2(+) breast cancer model using PET-SPECT image guidance. The increased tumor uptake of the pretargeting and drug delivery components was detected by PET-CT and SPECT-CT, respectively. The study showed a significant 92% reduction of the relative tumor volume in treated mice (RTV = 0.08 in 26 days), compared to the untreated control mice (RTV = 1.78 in 11 days) and to mice treated with only HSA-DM1-Tt-[99mTc-HyNic] (RTV = 1.88 in 16 days). Multimodality PET-SPECT image-guided and pretargeted drug delivery can be utilized to maximize efficacy, predict therapeutic response, and minimize systemic toxicity.

Recombinant immunotoxins development for HER2-based targeted cancer therapies

Understanding the molecular mechanisms of cancer biology introduces targeted therapy as a complementary method along with other conventional therapies. Recombinant immunotoxins are tumor specific antibodies that their recognizing fragment is utilized for delivering modified toxins into tumor cells. These molecules have been considered as a targeted strategy in the treatment of human cancers. HER2 tumor biomarker is a transmembrane tyrosine kinase receptor that can be used for targeted therapies in the forms of anti-HER2 monoclonal antibodies, antibody-drug conjugates and immunotoxins. There have been many studies on HER2-based immunotoxins in recent years, however, little progress has been made in the clinical field which demanded more improvements. Here, we summarized the HER2 signaling and it's targeting using immunotherapeutic agents in human cancers. Then, we specifically reviewed anti-HER2 immunotoxins, and their strengths and drawbacks to highlight their promising clinical impact.

Design, synthesis, HER2 inhibition and anticancer evaluation of new substituted 1,5-dihydro-4,1-benzoxazepines

A series of 11 new substituted 1,5-dihydro-4,1-benzoxazepine derivatives was synthesised to study the influence of the methyl group in the 1-(benzenesulphonyl) moiety, the replacement of the purine by the benzotriazole bioisosteric analogue, and the introduction of a bulky substituent at position 6 of the purine, on the biological effects. Their inhibition against isolated HER2 was studied and the structure–activity relationships have been confirmed by molecular modelling studies. The most potent compound against isolated HER2 is 9a with an IC₅₀ of 7.31 µM. We have investigated the effects of the target compounds on cell proliferation. The most active compound (7c) against all the tumour cell lines studied (IC₅₀ 0.42–0.86 µM) does not produce any modification in the expression of pro-caspase 3, but increases the caspase 1 expression, and promotes pyroptosis.

UCP-2 inhibitor enhanced the efficacy of trastuzumab against HER2 positive breast cancer cells

Purpose

This study aimed to investigate the possibility of UCP-2 inhibitor in reducing acquired resistance of trastuzumab to improve the outcome of patients receiving trastuzumab therapy by exploring the relationship between UCP-2 expression and HER2 signaling pathway and examining whether UCP-2 expression was modulated by trastuzumab treatment.

Methods

32 women diagnosed with primary HER2-positive breast cancer were recruited in this study. Needle biopsy was obtained from patients before they received at least four cycles neoadjuvant therapy containing trastuzumab in combination with chemotherapy. Surgical tumor biopsy was obtained during surgical procedure after the neoadjuvant therapy. Levels of HER2 phosphorylation and UCP-2 expression were detected by immunohistochemistry (IHC) and compared between tumor needle biopsy tissue and surgical tumor samples of these patients, as well as in BT474 breast cancer cells before and after trastuzumab treatment. HER2-selective phosphorylation/kinase activity inhibitor ONT-380 was used to identify the correlation between HER2 phosphorylation level and UCP-2 expression. UCP-2 inhibitor Genipin was then used to evaluate the apoptosis index in BT474 cells treated with trastuzumab.

Results

UCP-2 expression was significantly elevated in surgical tumor samples from breast cancer patients receiving trastuzumab in a neoadjuvant setting. We further confirmed our findings in HER2-positive BT474 cell line and found that trastuzumab treatment induced phosphorylation of HER2 and the overexpression of UCP-2, and the latter can be reversed by HER2 selective kinase inhibitor ONT-380. Moreover, UCP-2 inhibitor Genipin significantly enhanced the proliferation suppression effects of trastuzumab and markedly promoted apoptosis.

Conclusion

Taken together, our study identified UCP-2 as a novel therapeutic target for HER2 positive breast cancer and UCP-2 inhibitor may have great potential to enhance the response rate and efficacy of trastuzumab therapy.

Diagnostics and Therapeutics in Targeting HER2 Breast Cancer: A Novel Approach

Breast cancer is one of the most commonly occurring cancers in women globally and is the primary cause of cancer mortality in females. BC is highly heterogeneous with various phenotypic expressions. The overexpression of HER2 is responsible for 15-30% of all invasive BC and is strongly associated with malignant behaviours, poor prognosis and decline in overall survival. Molecular imaging offers advantages over conventional imaging modalities, as it provides more sensitive and specific detection of tumours, as these techniques measure the biological and physiological processes at the cellular level to visualise the disease. Early detection and diagnosis of BC is crucial to improving clinical outcomes and prognosis. While HER2-specific antibodies and nanobodies may improve the sensitivity and specificity of molecular imaging, the radioisotope conjugation process may interfere with and may compromise their binding functionalities. Aptamers are single-stranded oligonucleotides capable of targeting biomarkers with remarkable binding specificity and affinity. Aptamers can be functionalised with radioisotopes without compromising target specificity. The attachment of different radioisotopes can determine the aptamer's functionality in the treatment of HER2(+) BC. Several HER2 aptamers and investigations of them have been described and evaluated in this paper. We also provide recommendations for future studies with HER2 aptamers to target HER2(+) BC.

Nature-Inspired Nanoparticles as Paclitaxel Targeted Carrier for the Treatment of HER2-Positive Breast Cancer

Despite the advances made in the fight against HER2-positive breast cancer, the need for less toxic therapies and strategies that avoid the apparition of resistances is indisputable. For this reason, a targeted nanovehicle for paclitaxel and trastuzumab, used in the first-line treatment of this subtype of breast cancer, had already been developed in a previous study. It yielded good results in vitro but, with the aim of further reducing paclitaxel effective dose and its side effects, a novel drug delivery system was prepared in this work. Thus, polydopamine nanoparticles, which are gaining popularity in cancer nanomedicine, were novelty loaded with paclitaxel and trastuzumab. The effectiveness and selectivity of the nanoparticles obtained were validated in vitro with different HER2-overexpressing tumor and stromal cell lines. These nanoparticles showed more remarkable antitumor activity than the nanosystem previously designed and, in addition, to affect stromal cell viability rate less than the parent drug. Moreover, loaded polydopamine nanoparticles, which notably increased the number of apoptotic HER2-positive breast cancer cells after treatment, also maintained an efficient antineoplastic effect when validated in tumor spheroids. Thereby, these bioinspired nanoparticles charged with both trastuzumab and paclitaxel may represent an excellent approach to improve current HER2-positive breast cancer therapies.

Disruption of FOXO3a-miRNA feedback inhibition of IGF2/IGF-1R/IRS1 signaling confers Herceptin resistance in HER2-positive breast cancer

Resistance to Herceptin represents a significant challenge for successful treatment of HER2-positive breast cancer. Here, we show that in Herceptin-sensitive cells, FOXO3a regulates specific miRNAs to control IGF2 and IRS1 expression, retaining basic IGF2/IGF-1R/IRS1 signaling. The basic activity maintains expression of PPP3CB, a subunit of the serine/threonine-protein phosphatase 2B, to restrict FOXO3a phosphorylation (p-FOXO3a), inducing IGF2- and IRS1-targeting miRNAs. However, in Herceptin-resistant cells, p-FOXO3a levels are elevated due to transcriptional suppression of PPP3CB, disrupting the negative feedback inhibition loop formed by FOXO3a and the miRNAs, thereby upregulating IGF2 and IRS1. Moreover, we detect significantly increased IGF2 in blood and IRS1 in the tumors of breast cancer patients with poor response to Herceptin-containing regimens. Collectively, we demonstrate that the IGF2/IGF-1R/IRS1 signaling is aberrantly activated in Herceptin-resistant breast cancer via disruption of the FOXO3a-miRNA negative feedback inhibition. Such insights provide avenues to identify predictive biomarkers and effective strategies overcoming Herceptin resistance.

Role of the IGF-1 Axis in Overcoming Resistance in Breast Cancer

Over the last two decades, many studies have demonstrated that the insulin-like growth factor-1 (IGF-1) is involved in a number of patho-physiological processes, as well as in the development of different types of solid tumors, including breast cancer (BC). Preclinical and clinical data showed that IGF-1 receptor (R) is overexpressed and hyper-phosphorylated in several subtypes of BCs. The central implications of this pathway in tumor cell proliferation and metastasis make it an important therapeutic target. Moreover, the IGF-1 axis has shown strong interconnection with estrogen regulation and endocrine therapy, suggesting a possible solution to anti-estrogen resistance. IGF-1R might also interfere with other pivotal therapeutic strategies, such as anti HER2 treatments and mTOR inhibitors; several clinical trials are ongoing evaluating the role of IGF-1R inhibition in modulating resistance mechanisms to target therapies. Our aim is to offer an overview of the most recent and significant field of application of IGF-1 inhibitors and relevant therapeutic strategies, weighing their possible future impact on clinical practice.

Synergistic antitumor effect of the anti-ErbB2 antibodies trastuzumab and H2-18 on trastuzumab-resistant gastric cancer cells

Trastuzumab resistance is a severe problem in the treatment of ErbB2-amplified cancer. Although trastuzumab plus pertuzumab is able to partly overcome trastuzumab resistance in ErbB2-overexpressing cancer, its antitumor efficacy remains limited. The present study investigated the antitumor activity of the combination of trastuzumab with H2-18, which is an antibody targetinsg ErbB2 domain I. Cell proliferation and inhibition experiments indicated that H2-18 and trastuzumab synergistically inhibited the proliferation of both the trastuzumab-sensitive gastric cancer cell line, NCI-N87 and the trastuzumab-resistant gastric cancer cell line, NCI-N87-TraRT. Furthermore, H2-18 plus trastuzumab inhibited the growth of NCI-N87-TraRT cells more effectively than trastuzumab plus pertuzumab, both in vitro and in vivo. Compared with trastuzumab plus pertuzumab, H2-18 plus trastuzumab had a potent ability to inhibit NCI-N87-TraRT cells to form colonies. Notably, H2-18 plus trastuzumab was more effective in inducing cell death than trastuzumab plus pertuzumab. The in vivo studies demonstrated that H2-18 plus trastuzumab effectively inhibited the growth of both NCI-N87 and NCI-N87-TraRT xenograft tumors. Further experiments revealed that in NCI-N87-TraRT cells, H2-18 plus trastuzumab was comparable to trastuzumab plus pertuzumab in the inhibition of phosphorylated (p-)HER3, p-AKT and p-ERK. However, compared with trastuzumab plus pertuzumab, H2-18 plus trastuzumab effectively activated ROS production and the phosphorylation of JNK and c-jun in NCI-N87-TraRT cells. Therefore, the superior antitumor efficacy of H2-18 plus trastuzumab over trastuzumab plus pertuzumab may be mainly attributable to the potent cell death-inducing activity. In addition, the in vitro and in vivo antitumor effect of the combination of H2-18, trastuzumab and pertuzumab were further investigated. The results revealed that H2-18 plus trastuzumab plus pertuzumab exhibited a maximal antitumor effect among all the anti-ErbB2 monoclonal antibody combinations tested. In summary, H2-18 plus trastuzumab may have potential as an effective strategy to overcome the resistance to trastuzumab in ErbB2-amplified gastric cancer cell lines.

Bispecific Antibody Molecule Inhibits Tumor Cell Proliferation More Efficiently Than the Two-Molecule Combination

Background

Monoclonal antibodies (mAbs) have proved to be a valuable tool for the treatment of different cancer types. However, clinical use of an increasing number of mAbs, have also highlighted limitations with monotherapy for cancers, in particular for such with more complex mechanisms, requiring action on additional molecules or pathways, or for cancers quickly acquiring resistance following monotherapy. An example for the latter is the mAb trastuzumab, FDA approved for treatment of metastatic gastric carcinoma. To circumvent this, researchers have reported synergistic, anti-proliferative effects by combination targeting of HER2 and EGFR by trastuzumab and the EGFR-targeting mAb Cetuximab overcoming trastuzumab resistance.

Methods

Maintaining the proven functionality of trastuzumab, we have designed bi-specific antibody molecules, called AffiMabs, by fusing an EGFR-targeting Affibody molecule to trastuzumab’s heavy or light chains. Having confirmed binding to EGFR and Her2 and cytotoxicity of our AffiMabs, we analyzed apoptosis rate, receptor surface levels, phosphorylation levels of receptors and associated signaling pathways as well as differentially expressed genes on transcriptome level with the aim to elucidate the mode of action of our AffiMabs.

Results

The AffiMabs are able to simultaneously bind HER2 and EGFR and show increased cytotoxic effect compared to the original trastuzumab therapeutic molecule and, more importantly, even to the combination of trastuzumab and EGFR-targeting Affibody molecule. Analyzing the mode of action, we could show that bi-specific AffiMabs lead to reduced surface receptor levels and a downregulation of cell cycle associated genes on transcriptome level.

Conclusion

Our study shows that transcriptome analysis can be used to validate the choice of receptor targets and guide the design of novel multi-specific molecules. The inherent modularity of the AffiMab format renders it readily applicable to other receptor targets.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40268-021-00339-2.

Confocal Laser Scanning Microscopy and Fluorescence Correlation Methods for the Evaluation of Molecular Interactions

Confocal laser scanning microscopy (CLSM) and related microscopic techniques allow a unique and versatile approach to image and analyze living cells due to their specificity and high sensitivity. Among confocal related techniques, fluorescence correlation methods, such as fluorescence correlation spectroscopy (FCS) and dual-color fluorescence cross-correlation spectroscopy (FCCS), are highly sensitive biophysical methods for analyzing the complex dynamic events of molecular diffusion and interaction change in live cells as well as in solution by exploiting the characteristics of fluorescence signals. Analytical and quantitative information from FCS and FCCS coupled with fluorescence images obtained from CLSM can now be applied in convergence science such as drug delivery and nanomedicine, as well as in basic cell biology. In this chapter, a brief introduction into the physical parameters that can be obtained from FCS and FCCS is first provided. Secondly, experimental examples of the methods for evaluating the parameters is presented. Finally, two potential FCS and FCCS applications for convergence science are introduced in more detail.

Association Between the HER2 Protein Expression Level and the Efficacy of Neoadjuvant Chemotherapy in HER2-Positive Breast Cancer

Objective

This study aimed to assess the relationship between human epidermal growth factor receptor-2 (HER2) protein expression level and clinicopathological features of HER2-positive breast cancer, and to analyze whether the expression level of HER2 protein could predict the response to anti-HER2 therapy.

Methods

The present study included 296 patients with HER2-positive breast cancer receiving neoadjuvant chemotherapy (NAC) containing trastuzumab between January 2014 and November 2019. The univariate comparisons of the differences in clinicopathological parameters between different HER2 protein expression groups, and the association between HER2 protein expression level and efficacy of NAC, were made using a X² test or Mann–Whitney U-test. Multivariate analyses of the differences in clinicopathological parameters between different HER2 protein expression groups, and the association between HER2 protein expression level and efficacy of NAC, were performed using logistic regression analysis.

Results

A total of 110 patients achieved a pathological complete response (pCR) after NAC. The pCR rate was 37.2%. The study showed that patients who were HR-negative, AR-positive, and CK5/6-negative had significantly higher expression level of HER2 protein [odds ratio (OR) = 0.183, P < 0.001; OR = 6.414, P = 0.004; OR = 0.261, P = 0.004, respectively]. Patients with HER2 3+ detected by immunohistochemistry (IHC) had significantly higher pCR rates compared with patients with HER2 2+. The HER2 protein expression level might effectively predict the efficacy of NAC in patients with HER2-positive breast cancer (OR = 3.520, P = 0.003).

Conclusion

The HER2 protein expression level was related to multiple clinical features in patients with HER2-positive breast cancer. For example, hormone receptor, androgen receptor, cytokeratin5/6, and HER2 protein expression level may be used to predict the response to NAC in patients with HER2-positive breast cancer and may serve as a predictive factor for NAC efficacy.

Genotype Driven Therapy for Non-Small Cell Lung Cancer: Resistance, Pan Inhibitors and Immunotherapy

Eighty-five percent of patients with lung cancer present with Non-small Cell Lung Cancer (NSCLC). Targeted therapy approaches are promising treatments for lung cancer. However, despite the development of targeted therapies using Tyrosine Kinase Inhibitors (TKI) as well as monoclonal antibodies, the five-year relative survival rate for lung cancer patients is still only 18%, and patients inevitably become resistant to therapy. Mutations in Kirsten Ras Sarcoma viral homolog (KRAS) and epidermal growth factor receptor (EGFR) are the two most common genetic events in lung adenocarcinoma; they account for 25% and 20% of cases, respectively. Anaplastic Lymphoma Kinase (ALK) is a transmembrane receptor tyrosine kinase, and ALK rearrangements are responsible for 3-7% of NSCLC, predominantly of the adenocarcinoma subtype, and occur in a mutually exclusive manner with KRAS and EGFR mutations. Among drug-resistant NSCLC patients, nearly half exhibit the T790M mutation in exon 20 of EGFR. This review focuses on some basic aspects of molecules involved in NSCLC, the development of resistance to treatments in NSCLC, and advances in lung cancer therapy in the past ten years. Some recent developments such as PD-1-PD-L1 checkpoint-based immunotherapy for NSCLC are also covered.

Rapid, Cost-Effective Peptide/Nucleic Acid-Based Platform for Therapeutic Antibody Monitoring in Clinical Samples

We demonstrate here a homogeneous assay, named NanoHybrid, for monoclonal antibody quantification directly in serum samples in a single-step format. NanoHybrid is composed of both synthetic peptide nucleic acids (PNAs) and nucleic acid strands conjugated to recognition elements and optical labels and is designed to allow fast fluorescence quantification of a therapeutic antibody. More specifically, we have characterized our analytical assay for the detection of trastuzumab (Herceptin), a monoclonal antibody (mAb) drug used for breast cancer treatment and for tumors overexpressing the HER2/neu protein. We show here that NanoHybrid is capable of performing fast drug quantification directly in blood serum. The results obtained with a pool of samples from breast cancer patients under trastuzumab treatment are compared with CE-IVD ELISA (enzyme-linked immunosorbent assay) showing a good agreement (Cohen's K = 0.729). Due to the modular nature of the NanoHybrid platform, this technology can be programmed to potentially detect and quantify any antibody for which a high-affinity recognition element has been characterized. We envision the application of NanoHybrid in a point-of-care (POC) drug monitoring system based on disposable kits for therapeutic drug management.

Cyclin E overexpression confers resistance to trastuzumab through noncanonical phosphorylation of SMAD3 in HER2+ breast cancer

The efficacy of trastuzumab, a treatment for HER2+ breast cancer, can be limited by the development of resistance. Cyclin E (CCNE) overexpression has been implicated in trastuzumab resistance. We sought to uncover a potential mechanism for this trastuzumab resistance and focused on a model of CCNE overexpressing HER2+ breast cancer and noncanonical phosphorylation of the TGF-β signaling protein, SMAD3. Network analysis of transcriptional activity in a HER2+, CCNE overexpressing, trastuzumab-resistant cell line (BT474R2) identified decreased SMAD3 activity was associated with treatment resistance. Immunoblotting showed SMAD3 expression was significantly downregulated in BT474R2 cells (p < .01), and noncanonical phosphorylation of SMAD3 was increased in these CCNE-overexpressing cells. Also, in response to CDK2 inhibition, expression patterns linked to restored canonical SMAD3 signaling, including decreased cMyc and increased cyclin-dependent inhibitor, p15, were identified. The BT474R2 cell line was modified through overexpression of SMAD3 (BT474R2-SMAD3), a mutant construct resistant to CCNE-mediated noncanonical phosphorylation of SMAD3 (BT474R2-5M), and a control (BT474R2-Blank). In vitro studies examining the response to trastuzumab showed increased sensitivity to treatment for BT474R2-5M cells. These findings were then validated in NSG mice inoculated with BT474R2-5M cells or BT474R2 control cells. After treatment with trastuzumab, the NSG mice inoculated with BT474R2-5M cells developed significantly lower tumor volumes (p < .001), when compared to mice inoculated with BT474R2 cells. Taken together, these results indicate that for patients with HER2+ breast cancer, a mechanism of CCNE-mediated trastuzumab resistance, regulated through noncanonical SMAD3 phosphorylation, could be treated with CDK2 inhibition to help enhance the efficacy of trastuzumab therapy.

Trastuzumab: More than a Guide in HER2-Positive Cancer Nanomedicine

HER2 overexpression, which occurs in a fifth of diagnosed breast cancers as well as in other types of solid tumors, has been traditionally linked to greater aggressiveness. Nevertheless, the clinical introduction of trastuzumab has helped to improve HER2-positive patients' outcomes. As a consequence, nanotechnology has taken advantage of the beneficial effects of the administration of this antibody and has employed it to develop HER2-targeting nanomedicines with promising therapeutic activity and limited toxicity. In this review, the molecular pathways that could be responsible for trastuzumab antitumor activity will be briefly summarized. In addition, since the conjugation strategies that are followed to develop targeting nanomedicines are essential to maintaining their efficacy and tolerability, the ones most employed to decorate drug-loaded nanoparticles and liposomes with trastuzumab will be discussed here. Thus, the advantages and disadvantages of performing this trastuzumab conjugation through adsorption or covalent bindings (through carbodiimide, maleimide, and click-chemistry) will be described, and several examples of targeting nanovehicles developed following these strategies will be commented on. Moreover, conjugation methods employed to synthesized trastuzumab-based antibody drug conjugates (ADCs), among which T-DM1 is well known, will be also examined. Finally, although trastuzumab-decorated nanoparticles and liposomes and trastuzumab-based ADCs have proven to have better selectivity and efficacy than loaded drugs, trastuzumab administration is sometimes related to side toxicities and the apparition of resistances. For this reason also, this review focuses at last on the important role that newer antibodies and peptides are acquiring these days in the development of HER2-targeting nanomedicines.

NCAPG confers trastuzumab resistance via activating SRC/STAT3 signaling pathway in HER2-positive breast cancer

HER2+ breast cancer (BC) is characterized by rapid growth, early recurrence, early metastasis, and chemoresistance. Trastuzumab is the most effective treatment for HER2+ BC and effectively reduces the risk of recurrence and death of patients. Resistance to trastuzumab results in cancer recurrence and metastasis, leading to poor prognosis of HER2+ BC. In the present study, we found that non-structural maintenance of chromosome condensin 1 complex subunit G (NCAPG) expression was highly upregulated in trastuzumab-resistant HER2+ BC. Ectopic NCAPG was positively correlated with tumor relapse and shorter survival in HER2+ BC patients. Moreover, overexpression of NCAPG promoted, while silencing of NCAPG reduced, the proliferative and anti-apoptotic capacity of HER2+ BC cells both in vitro and in vivo, indicating NCAPG reduces the sensitivity of HER2+ BC cells to trastuzumab and may confer trastuzumab resistance. Furthermore, our results suggest that NCAPG triggers a series of biological cascades by phosphorylating SRC and enhancing nuclear localization and activation of STAT3. To summarize, our study explores a crucial role for NCAPG in trastuzumab resistance and its underlying mechanisms in HER2+ BC, and suggests that NCAPG could be both a potential prognostic marker as well as a therapeutic target to effectively overcome trastuzumab resistance.

Acquired resistance to trastuzumab/pertuzumab or to T-DM1 in vivo can be overcome by HER2 kinase inhibition with TAS0728

HER2‐targeting antibodies (trastuzumab, pertuzumab) and a HER2‐directed antibody‐drug conjugate (trastuzumab emtansine: T‐DM1) are used for the treatment of HER2‐overexpressing breast cancer. However, these treatments eventually become ineffective due to acquired resistance and there is an urgent need for alternative therapies. TAS0728 is a small‐molecule, irreversible selective HER2 kinase inhibitor. In the present study, we established new in vivo models of cancer resistance by continuous exposure to a combination of trastuzumab and pertuzumab or to T‐DM1 for evaluating the effect of TAS0728 on HER2 antibody‐resistant populations. Treatment with trastuzumab and pertuzumab or with T‐DM1 initially induced tumor regression in NCI‐N87 xenografts. However, tumor regrowth during treatment indicated loss of drug effectiveness. In tumors with acquired resistance to trastuzumab and pertuzumab or to T‐DM1, HER2‐HER3 phosphorylation was retained. Switching to TAS0728 resulted in a significant anti‐tumor effect associated with HER2‐HER3 signal inhibition. No alternative receptor tyrosine kinase activation was observed in these resistant tumors. Furthermore, in a patient‐derived xenograft model derived from breast cancer refractory to both trastuzumab/pertuzumab and T‐DM1, TAS0728 exerted a potent anti‐tumor effect. These results suggest that tumors with acquired resistance to trastuzumab and pertuzumab and to T‐DM1 are still dependent on oncogenic HER2‐HER3 signaling and are vulnerable to HER2 signal inhibition by TAS0728. These results provide a rationale for TAS0728 therapy for breast cancers that are refractory to established anti‐HER2 therapies.

Anti-HER2 induced myeloid cell alterations correspond with increasing vascular maturation in a murine model of HER2+ breast cancer

BACKGROUND

Therapy targeted to the human epidermal growth factor receptor type 2 (HER2) is used in combination with cytotoxic therapy in treatment of HER2+ breast cancer. Trastuzumab, a monoclonal antibody that targets HER2, has been shown pre-clinically to induce vascular changes that can increase delivery of chemotherapy. To quantify the role of immune modulation in treatment-induced vascular changes, this study identifies temporal changes in myeloid cell infiltration with corresponding vascular alterations in a preclinical model of HER2+ breast cancer following trastuzumab treatment.

METHODS

HER2+ tumor-bearing mice (N = 46) were treated with trastuzumab or saline. After extraction, half of each tumor was analyzed by immunophenotyping using flow cytometry. The other half was quantified by immunohistochemistry to characterize macrophage infiltration (F4/80), vascularity (CD31 and α-SMA), proliferation (Ki67) and cellularity (H&E). Additional mice (N = 10) were used to quantify differences in tumor cytokines between control and treated groups.

RESULTS

Immunophenotyping showed an increase in macrophage infiltration 24 h after trastuzumab treatment (P ≤ 0.05). With continued trastuzumab treatment, the M1 macrophage population increased (P = 0.02). Increases in vessel maturation index (i.e., the ratio of α-SMA to CD31) positively correlated with increases in tumor infiltrating M1 macrophages (R = 0.33, P = 0.04). Decreases in VEGF-A and increases in inflammatory cytokines (TNF-α, IL-1β, CCL21, CCL7, and CXCL10) were observed with continued trastuzumab treatment (P ≤ 0.05).

CONCLUSIONS

Preliminary results from this study in a murine model of HER2+ breast cancer show correlations between immune modulation and vascular changes, and reveals the potential for anti-HER2 therapy to reprogram immunosuppressive components of the tumor microenvironment. The quantification of immune modulation in HER2+ breast cancer, as well as the mechanistic insight of vascular alterations after anti-HER2 treatment, represent novel contributions and warrant further assessment for potential clinical translation.

The trastuzumab era: current and upcoming targeted HER2+ breast cancer therapies

Human Epidermal Growth Factor Receptor 2-positive breast cancer (HER2+ BC) is defined by increased amplification of the ERBB2/neu oncogene and/or overexpression of its associated HER2 transmembrane receptor protein. HER2+ BC represents approximately 15-20% of breast cancer, and it is independently associated with a higher grade, more aggressive phenotype, and worse prognosis. With the advent of trastuzumab, the prognostic landscape for HER2+ BC patients has considerably improved. However, both de novo and acquired resistance to trastuzumab remain a significant obstacle for many patients, requiring novel therapies for further clinical benefit. Over the last two decades, there has been extraordinary progress in the development of HER2+ BC treatment regimens, with extensions into HER2-amplified gastroesophageal junction cancer via the NCI-MATCH precision medicine trial program (NCT02465060). Trastuzumab, pertuzumab, T-DM1, and lapatinib are commonly recommended as a single agent (along with chemotherapy) or in combinations of anti-HER2 agents in neoadjuvant, adjuvant and metastatic settings according to National Comprehensive Cancer Network (NCCN) guidelines. Currently, the combination of trastuzumab, pertuzumab, and taxane chemotherapy are first-line for HER2+/HR- metastatic breast cancer with potential breakthrough therapies such as trastuzumab-deruxtecan (DS-8201a), margetuximab and tucatinib (ONT-380) on the horizon. Furthermore, recent clinical trials have demonstrated the potential utility of hormone receptor status, PAM-50 luminal intrinsic subtype, PD-L1, and TIL as predictive biomarkers for response to HER2+ therapies. We briefly introduce the origin of HER2, the invention of trastuzumab, and the classification of HER2+ BC. Each HER2-targeted therapy is then presented by indication, mechanism of action, and relevant clinical trials with subsequent elaboration and contextualization within clinical settings with an epilogue of potential future biomarkers for clinical use in HER2+ BC. We summarize the most significant and updated research in clinical practice relevant to HER2+ BC management and highlight the clinical status of upcoming anti-HER2 agents as well as immunotherapy drugs in combination with anti-HER2 agents.

Real-World Data of Triplet Combination of Trastuzumab, Lapatinib, and Chemotherapy in HER2-Positive Metastatic Breast Cancer: A Multicenter Retrospective Study

Introduction: Combination of trastuzumab (T) and lapatinib (L) has been showed to significantly improve the prognosis of HER2+ heavily pretreated metastatic breast cancer (MBC). Whether TL combined chemotherapy (TLC) can further improve the efficacy in HER2+ MBC remains to be further studied. The aim of the study was to report the first real-world data of TLC in HER2+ MBC, including the efficacy, safety and treatment patterns.

Methods: Patients with HER2+ MBC treated with TLC in 5 institutions of China from September 2013 to July 2019 were included. Progression free survival (PFS), objective response rate (ORR), overall survival (OS), toxicity profile and treatment pattern were reported.

Results: A total of 285 patients were included. 88.8% were exposed to trastuzumab and 49.2% received 2 or more lines of systematic therapy before TLC previously. The most common chemotherapy regimens combined with TL were capecitabine (40.7%) and vinorelbine (21.4%) and almost 1/3 received maintenance treatment after TLC. Median PFS was 10.9 months while patients received TLC as first line treatment showed longest median PFS of 20.7 months. Patients pretreated with trastuzumab showed a median PFS of 10.2 months. In patients who pretreated with trastuzumab, the continuation of trastuzumab on the basis of standard lapatinib plus capecitabine had a median PFS of 11.3 months. TL combined with capecitabine or vinorelbine showed no significant difference in median PFS, though TL combined with capecitabine had numerically prolongation (11.4 vs. 8.5 months, p = 0.231). Patients had brain metastasis (BM) also showed a median PFS (intracranial and extracranial lesions considered) of 10.6 months. Lines of systematic metastatic treatment was an independent predictive factor of PFS. The median OS was not reached. Two hundred and seventy seven patients were included in ORR analysis. ORR was 42.6%. Toxicities of triplet combinations were tolerable and the most common grade 3 and 4 adverse events were neutropenia (16.8%).

Conclusions: TLC demonstrated promising effects and tolerable safety in HER2+MBC, even in patients with BM, providing a theoretical basis for clinical practice.

Clinical Trial Registration:ClinicalTrials.gov, Identifier: NCT04001634.

A new anti-HER2 antibody that enhances the anti-tumor efficacy of trastuzumab and pertuzumab with a distinct mechanism of action

The majority of patients with metastatic breast cancer who are treated with the anti-HER2 monoclonal antibody, trastuzumab, generally develop resistance to the drug within a year after initiation of the treatment. Here we describe a new anti-HER2 humanized monoclonal antibody, 19H6-Hu, which binds to HER2 extracellular domain (ECD) with high affinity and inhibits proliferation of multiple HER2-overexpressing cancer cell lines as a single agent or in combination with trastuzumab. 19H6-Hu binds to the domain III in proximity to the domain IV of HER2 ECD, which differs from trastuzumab and pertuzumab. 19H6-Hu in combination with trastuzumab was more effective at blocking phosphorylation of ERK1/2, AKT(S473)and HER2 (Y1248) in HER2-positive cancer cells compared to trastuzumab alone or in combination with pertuzumab. Combination of three antibodies, 19H6-Hu, inetetamab (a trastuzumab analog) and pertuzumab exhibited much stronger inhibition of large NCI-N87 tumor xenografts (>400mm³) than the current standard of care, inetetamab (trastuzumab) plus Docetaxel (DTX), as well as the combination of 19H6-Hu, inetetamab and DTX. Our results highlight the functional variability of HER2 domains and provide a new insight into the design of HER2-targeting agents.