Anti-HER agents in gastric cancer: from bench to bedside

DNA Tetrahedron Mass-Tagged Probe Set for the Programmed Detection of Protein Trimers by Point-to-Point Recognition and Induced Self-Assembly in Living Cells

Multimeric proteins normally perform different biological functions from their monomer components. Thus, precise recognition and quantitative detection of multimeric proteins can benefit a better understanding of complex biological processes and their roles in disease diagnosis and treatment. The challenge herein is to distinguish the multimeric proteins containing identical monomer components and recognize all the monomers in a multimeric protein on spatial scales. This situation is likely to become more significant for homomultimeric proteins. In this study, a DNA polyhedron mass-tagged probe set strategy was developed for the programmed detection of multimeric proteins in living cells. The probe set comprised recognition and displacement probes, a DNA polyhedron probe, and a mass-tagged probe. After point-to-point recognition of each monomer in the target protein complex by recognition and displacement probes, the DNA polyhedron probe could integrate the information on all the protein monomers by carrying out induced self-assembly via a cascaded toehold-mediated strand-displacement (TMSD) reaction. Afterward, the mass-tagged probe collected the integrated information, and the mass tag in the probe was released by ultraviolet (UV) irradiation and detected by mass spectrometry (MS). Using the tmTNF-α homotrimer as an example, its expression levels in different breast cancer cell lines were ultimately determined using this probe set containing a DNA tetrahedron probe. This study is among the first to quantitatively detect multimeric proteins in living cells. Using a similar strategy, more DNA polyhedron mass-tagged probe sets can be developed for the detection of higher-order multimeric proteins.

Ultrasound-triggered topical oxygen delivery enhances synergistic sonodynamic and antibody therapies against hypoxic gastric cancer

Hypoxia is a common feature of malignant tumors, which can accelerate tumor growth and reduce the sensitivity of chemotherapy and sonodynamic therapy by activating the hypoxia-inducible factor (HIF) signaling pathway. In HER2-positive gastric cancer, HER2 overexpression enhances HIF-1α synthesis, exacerbating hypoxia and impairing sonodynamic therapy. It also reduces trastuzumab-mediated antibody-dependent cytotoxicity, significantly compromising therapeutic outcomes. Herein, pyropheophorbide-conjugated lipid (pyropheophorbide-lipid, PL) and trastuzumab were fabricated into targeted nanoparticles (TP NPs) for loading perfluorobromooctane (PFOB) carrying oxygen (TPPO NPs), thus enabling oxygen self-supplied sonodynamic and antibody therapies. In vitro experiments showed that antibody targeting significantly increased the cellular uptake of sonosensitizers, and the controlled release of oxygen was dependent on ultrasound parameters, greatly enhancing the killing effects of SDT and antibody therapy. In vivo animal experiments showed that TPPO NPs-mediated enhanced permeation and retention (EPR) effects, along with antibody targeting, improved the enrichment of sonosensitizers in tumors. Notably, ultrasound-triggered topical delivery of oxygen significantly alleviated tumor hypoxia and further improved the efficacy of SDT and antibody therapy. Given the good biosafety profile of TPPO NPs, this system holds great promise for future clinical applications in gastric cancer.

Targeting LINC00665/miR-199b-5p/SERPINE1 axis to inhibit trastuzumab resistance and tumorigenesis of gastric cancer via PI3K/AKt pathway

Long noncoding RNAs (lncRNAs) serve as critical mediators of tumor progression and drug resistance in cancer. Herein, we identified a lncRNA, LINC00665, associated with trastuzumab resistance and development in gastric cancer (GC). LINC00665 was highly expressed in GC tissues and high expression of LINC00665 was correlated with poor prognosis. LINC00665 knockdown was verified to suppress migration, invasion, and resistance to trastuzumab in GC. Furthermore, we found that LINC00665 participates in the infiltration of naive B cells, mast cells, and T follicular helper (Tfh) cells. Mechanistically, LINC00665 was confirmed to regulate tumorigenesis and trastuzumab resistance by activating PI3K/AKt pathway. LINC00665 sponged miR-199b-5p to interact with SERPINE1 expression, resulting in the increase of phosphorylation of AKt, thus participating in the PI3K/AKt pathway. To summarize, LINC00665 facilitated the tumorigenesis and trastuzumab resistance of GC by sponging miR-199b-5p and promoting SERPINE1 expression, which further activated PI3K/AKt signaling; this finding reveals a new mechanism by which LINC00665 modulates tumor development and drug resistance in GC.

Comprehensive review of signaling pathways and therapeutic targets in gastrointestinal cancers

Targeted therapy, the milestone in the development of human medicine, originated in 2004 when the FDA approved the first targeted agent bevacizumab for colorectal cancer treatment. This new development has resulted from drug developers moving beyond traditional chemotherapy, and several trials have popped up in the last two decades with an unprecedented speed. Specifically, EGF/EGFR, VEGF/VEGFR, HGF/c-MET, and Claudin 18.2 therapeutic targets have been developed in recent years. Some targets previously thought to be undruggable are now being newly explored, such as the RAS site. However, the efficacy of targeted therapy is extremely variable, especially with the emergence of new drugs and the innovative use of traditional targets for other tumors in recent years. Accordingly, this review provides an overview of the major signaling pathway mechanisms and recent advances in targeted therapy for gastrointestinal cancers, as well as future perspectives.

Pembrolizumab in combination with trastuzumab for treatment of HER2-positive advanced gastric or gastro-esophageal junction cancer

Introduction

Gastric cancer remains a challenging malignancy with a high global mortality rate. Recent advances in targeted therapy and immunotherapy have shown promise in improving patient outcomes. This paper reviews the impact of incorporating targeted agents such as trastuzumab and immunotherapeutic agents like pembrolizumab into standard chemotherapy regimens for gastric cancer treatment.

Methods

A comprehensive analysis was conducted on pivotal clinical trials, including KEYNOTE-590, KEYNOTE-811, and ToGA, focusing on their methodologies, patient populations, treatment regimens, and outcome measures. The review also explored emerging research avenues in precision medicine, particularly genomic sequencing and biomarker identification.

Aim

To assess the efficacy and survival benefits of adding trastuzumab and pembrolizumab to standard chemotherapy in the treatment of gastric cancer and to outline future directions in gastric cancer research.

Results

Including trastuzumab and pembrolizumab in treatment regimens for human epidermal growth factor receptor 2 (HER2)-positive and PD-L1-expressing gastric cancers significantly improved progression-free and overall survival rates compared to chemotherapy alone. These findings highlight the potential of personalized therapy in enhancing treatment outcomes. Furthermore, ongoing research into the gastric cancer microenvironment and the role of the microbiome suggests novel targets for future therapeutic interventions.

Conclusion

The integration of targeted and immunotherapeutic agents with traditional chemotherapy represents a pivotal shift in gastric cancer treatment, moving towards more personalized and effective regimens.

Clinical significance of CD166 and HER-2 in different types of gastric cancer

INTRODUCTION

Cluster of differentiation 166 (CD166), a cancer stem cell (CSC) marker, and human epidermal growth factor receptor 2 (HER-2) are expressed in a diversity of malignancies and is associated with tumor progression. Although studies regarding the importance of CSC markers and HER-2 in gastric cancer (GC) have rapidly developed, their clinicopathological, prognosis, and diagnosis value still remain unsatisfying in GC. Therefore, the present study aims to investigate the clinical, prognostic, and diagnostic significance of CD166 and HER-2 in different histological types of GC.

MATERIALS AND METHODS

Bioinformatic analysis was applied to determine the clinical importance of CD166 and HER-2 expression based on their tissue localization in primary GC tumors and the normal adjacent samples. The expression patterns, clinical significance, prognosis, and diagnosis value of CD166 and HER-2 proteins in tissue microarrays (TMAs) of 206 GC samples, including Signet Ring Cell (SRC) and intestinal types and also 28 adjacent normal tissues were evaluated using immunohistochemistry (IHC).

RESULTS

The results indicated that the expression of CD166 (membranous and cytoplasmic) and HER-2 were significantly up-regulated in tumor cells compared to adjacent normal tissues (P = 0.010, P < 0.001, and P = 0.011, respectively). A statistically significant association was detected between a high level of membranous expression of CD166 and lymphovascular invasion (P = 0.006); We also observed a statistically significant association between high cytoplasmic expression of CD166 protein and more invasion of the subserosa (P = 0.040) in the SRC type. In contrast, there was no correlation between the expression of HER-2 and clinicopathologic characteristics. Both CD166 and HER-2 showed reasonable accuracy and high specificity as diagnostic markers.

CONCLUSION

Our results confirmed that increased membranous and cytoplasmic expression of CD166 showed clinical significance in the SRC type and is associated with the progression of the disease and more aggressive tumor behaviors. These findings can be used to assist in designating subgroups of patients that require different follow-up strategies, and also, they might be utilized as the prognostic or diagnostic biomarkers in these types of GC for prospective clinical application.

Signaling pathways and therapeutic interventions in gastric cancer

Gastric cancer (GC) ranks fifth in global cancer diagnosis and fourth in cancer-related death. Despite tremendous progress in diagnosis and therapeutic strategies and significant improvements in patient survival, the low malignancy stage is relatively asymptomatic and many GC cases are diagnosed at advanced stages, which leads to unsatisfactory prognosis and high recurrence rates. With the recent advances in genome analysis, biomarkers have been identified that have clinical importance for GC diagnosis, treatment, and prognosis. Modern molecular classifications have uncovered the vital roles that signaling pathways, including EGFR/HER2, p53, PI3K, immune checkpoint pathways, and cell adhesion signaling molecules, play in GC tumorigenesis, progression, metastasis, and therapeutic responsiveness. These biomarkers and molecular classifications open the way for more precise diagnoses and treatments for GC patients. Nevertheless, the relative significance, temporal activation, interaction with GC risk factors, and crosstalk between these signaling pathways in GC are not well understood. Here, we review the regulatory roles of signaling pathways in GC potential biomarkers, and therapeutic targets with an emphasis on recent discoveries. Current therapies, including signaling-based and immunotherapies exploited in the past decade, and the development of treatment for GC, particularly the challenges in developing precision medications, are discussed. These advances provide a direction for the integration of clinical, molecular, and genomic profiles to improve GC diagnosis and treatments.

Proteomic characterization of gastric cancer response to chemotherapy and targeted therapy reveals new therapeutic strategies

Chemotherapy and targeted therapy are the major treatments for gastric cancer (GC), but drug resistance limits its effectiveness. Here, we profile the proteome of 206 tumor tissues from patients with GC undergoing either chemotherapy or anti-HER2-based therapy. Proteome-based classification reveals four subtypes (G-I-G-IV) related to different clinical and molecular features. MSI-sig high GC patients benefit from docetaxel combination treatment, accompanied by anticancer immune response. Further study reveals patients with high T cell receptor signaling respond to anti-HER2-based therapy; while activation of extracellular matrix/PI3K-AKT pathway impair anti-tumor effect of trastuzumab. We observe CTSE functions as a cell intrinsic enhancer of chemosensitivity of docetaxel, whereas TKTL1 functions as an attenuator. Finally, we develop prognostic models with high accuracy to predict therapeutic response, further validated in an independent validation cohort. This study provides a rich resource for investigating the mechanisms and indicators of chemotherapy and targeted therapy in GC.

Gasdermin B over-expression modulates HER2-targeted therapy resistance by inducing protective autophagy through Rab7 activation

Background

Gasdermin B (GSDMB) over-expression promotes poor prognosis and aggressive behavior in HER2 breast cancer by increasing resistance to therapy. Decoding the molecular mechanism of GSDMB-mediated drug resistance is crucial to identify novel effective targeted treatments for HER2/GSDMB aggressive tumors.

Methods

Different in vitro approaches (immunoblot, qRT-PCR, flow cytometry, proteomic analysis, immunoprecipitation, and confocal/electron microscopy) were performed in HER2 breast and gastroesophageal carcinoma cell models. Results were then validated using in vivo preclinical animal models and analyzing human breast and gastric cancer samples.

Results

GSDMB up-regulation renders HER2 cancer cells more resistant to anti-HER2 agents by promoting protective autophagy. Accordingly, the combination of lapatinib with the autophagy inhibitor chloroquine increases the therapeutic response of GSDMB-positive cancers in vitro and in zebrafish and mice tumor xenograft in vivo models. Mechanistically, GSDMB N-terminal domain interacts with the key components of the autophagy machinery LC3B and Rab7, facilitating the Rab7 activation during pro-survival autophagy in response to anti-HER2 therapies. Finally, we validated these results in clinical samples where GSDMB/Rab7/LC3B co-expression associates significantly with relapse in HER2 breast and gastric cancers.

Conclusion

Our findings uncover for the first time a functional link between GSDMB over-expression and protective autophagy in response to HER2-targeted therapies. GSDMB behaves like an autophagy adaptor and plays a pivotal role in modulating autophagosome maturation through Rab7 activation. Finally, our results provide a new and accessible therapeutic approach for HER2/GSDMB + cancers with adverse clinical outcome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02497-w.

Construction of a Mass-Tagged Oligo Probe Set for Revealing Protein Ratiometric Relationship Associated with EGFR-HER2 Heterodimerization in Living Cells

Protein dimerization, as the most common form of protein-protein interaction, can manifest more significant roles in cellular signaling than individual monomers. For example, excessive formation of EGFR-HER2 dimer has been implicated in cancer development and therapeutic resistance in addition to the overexpression of EGFR and HER2 proteins. Thus, quantitative evaluation of these heterodimers in living cells and revelation of their ratiometric relationship with protein monomers in dimerization may provide insights into clinical cancer management. To achieve this goal, the prerequisite is protein heterodimer quantification. Given the current lack of quantitative methods, we constructed a mass-tagged oligo nanoprobe set for quantification of EGFR-HER2 dimer in living cells. The mass-tagged oligo nanoprobe set contained two targeting probes (nucleic acid aptamers), a connector probe, a hairpin probe, and a photocleavable mass-tagged probe. Two distinct aptamers can recognize target protein monomers and initiate the subsequent hybridization cascade involving binding to the connector probe, formation of an initiator strand, opening of a hairpin probe, and ensuing hybridization with a photocleavable mass-tagged probe. Ultimately, the mass tag was released under ultraviolet light and then subjected to mass spectrometric analysis. In this way, the information regarding the interaction between two protein monomers was successfully converted to the quantitative signal of the mass tag. Using the assay, the expression level of EGFR-HER2 dimer and its relationship with individual protein monomers were determined in four breast cancer cell lines. We are among the first to obtain the absolute level of protein heterodimer, and this quantitative information may be vital in understanding the molecular basis of cancer.

Gastric Cancer: Mechanisms, Biomarkers, and Therapeutic Approaches

Gastric cancer (GC) remains one of the most common deadly malignancies worldwide. Recently, several targeted therapeutics for treating unresectable or metastatic GC have been developed. Comprehensive characterization of the molecular profile and of the tumor immune microenvironment of GC has allowed researchers to explore promising biomarkers for GC treatment and has enabled a new paradigm in precision-targeted immunotherapy. In this article, we review established and promising new biomarkers relevant in GC, with a focus on their clinical implications, diagnostic methods, and the efficacy of targeted agents.

Immunotoxin IHP25-BT with low immunogenicity and off-target toxicity inhibits the growth and metastasis of trastuzumab-resistant tumor cells

Human epidermal growth factor receptor 2 (HER2) is overexpressed in some breast and gastric cancer patients. As the first HER2-targeteed therpeutic antibody, trastuzumab could significantly improve the prognosis of HER2-positive cancer patients. However, even responding patients inevitably get worse due to acquired resistance to trastuzumab after a period of treatment. Many HER2-targeted antibody drugs used wild-type tumor cells to conduct their corresponding preclinical experiments in vitro and in vivo. However, it is impossible to determine whether these newly developed drugs have antitumor effective to trastuzumab-resistant tumor cells. In the study, two trastuzumab-resistant HER2-positive tumor cell populations NCI-N87-TR and BT474-TR were generated. Then, we examined the anti-tumor effects of newly constructed immunotoxins with low immunogenicity and off-target toxicity based on the trastuzumab-resistant tumor cells both in vitro and in vivo. Results demonstrated that the immunotoxin IHP25-BT could not only effectively inhibit tumor growth but also inhibit liver metastasis of tumor cells in a mouse xenograft model. Furthermore, tumor tissue transcriptome sequencing was performed to clarify the potential mechanisms of inhibiting tumor cell distant metastasis by immunotoxin. In conclusion, this work describes a series of attractive therapeutic immunotoxins, the low immunogenicity and off-target toxicity making them promising for trastuzumab-resistant cancer therapy.

Beyond RAS and BRAF: HER2, a New Actionable Oncotarget in Advanced Colorectal Cancer

The human epidermal growth factor receptor 2 (HER2) is a well-established oncogenic driver and a successful therapeutic target in several malignancies, such as breast and gastric cancers. HER2 alterations, including amplification and somatic mutations, have also been detected in a small but not negligible subset of patients affected by advanced colorectal cancer (aCRC). However, to date, there are no available oncotargets in this malignancy beyond RAS and BRAF that are available. Here we present an overview on the present predictive and prognostic role of HER2 expression in aCRC, as well as on its consequent potential therapeutic implications from preclinical investigations towards ongoing trials testing anti-HER2 agents in aCRC. While HER2's role as a molecular predictive biomarker for anti-EGFR therapies in CRC is recognized, HER2 prognostic value remains controversial. Moreover, thanks to the impressive and growing body of clinical evidence, HER2 is strongly emerging as a new potential actionable oncotarget in aCRC. In conclusion, in the foreseeable future, HER2-targeted therapeutic strategies may integrate the algorithm of aCRC treatment towards an increasingly tailored therapeutic approach to this disease.

Hyperactivation of HER2-SHCBP1-PLK1 axis promotes tumor cell mitosis and impairs trastuzumab sensitivity to gastric cancer

Trastuzumab is the backbone of HER2-directed gastric cancer therapy, but poor patient response due to insufficient cell sensitivity and drug resistance remains a clinical challenge. Here, we report that HER2 is involved in cell mitotic promotion for tumorigenesis by hyperactivating a crucial HER2-SHCBP1-PLK1 axis that drives trastuzumab sensitivity and is targeted therapeutically. SHCBP1 is an Shc1-binding protein but is detached from scaffold protein Shc1 following HER2 activation. Released SHCBP1 responds to HER2 cascade by translocating into the nucleus following Ser273 phosphorylation, and then contributing to cell mitosis regulation through binding with PLK1 to promote the phosphorylation of the mitotic interactor MISP. Meanwhile, Shc1 is recruited to HER2 for MAPK or PI3K pathways activation. Also, clinical evidence shows that increased SHCBP1 prognosticates a poor response of patients to trastuzumab therapy. Theaflavine-3, 3'-digallate (TFBG) is identified as an inhibitor of the SHCBP1-PLK1 interaction, which is a potential trastuzumab sensitizing agent and, in combination with trastuzumab, is highly efficacious in suppressing HER2-positive gastric cancer growth. These findings suggest an aberrant mitotic HER2-SHCBP1-PLK1 axis underlies trastuzumab sensitivity and offer a new strategy to combat gastric cancer.

HER2-targeted therapies in gastric cancer

Molecular targeted therapy of cancer has always been the focus of clinicians. Among those therapeutic targets, the human epidermal growth factor receptor-2 (HER-2) signaling pathway is one of the most popular targets for translational research in cancer. However, unlike prospect in breast cancer, HER-2 inhibitor trastuzumab is the only molecular targeted drug approved by US Food and Drug Administration (FDA) for the first-line treatment of HER-2 positive advanced gastric cancer. On this basis, a variety of novel HER2- targeted drugs for gastric cancer are under development, and related clinical researches are in full swing, including small molecular kinase inhibitors (e.g., afatinib, neratinib, pyrotinib), antibody-drug conjugates (e.g., DS-8201a, RC48-ADC) and other novel therapies (e.g., ZW25, CAR-T, BVAC-B). In this study, we will summarize the recent advances in anti-HER-2 agents, potential mechanisms of resistance to HER2-targeted therapy in HER2-positive gastric cancer. We will also discuss the future prospects of potential strategies to overcome anti-HER-2 resistance and development of novel anti-HER-2 approaches for the treatment of HER2-positive gastric cancer patients.

Impact of HER2 status in resected gastric or gastroesophageal junction adenocarcinoma in a Western population

BACKGROUND

HER2 status is a predictive biomarker of response to trastuzumab in advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma. However, there is relatively little known about the role of HER2 in resected gastric or GEJ adenocarcinoma in the Western population.

METHODS

Retrospective, observational, single centre study of patients with gastric or GEJ adenocarcinoma undergoing surgery with curative intent between January 2007 and June 2014 in the University Hospital Complex of Santiago de Compostela. The expression of HER2 was determined by immunohistochemistry (IHC) using DAKO-HercepTest™ and gene amplification with DuoCISH using a DAKO-DuoCISH kit. The study of HER2 expression and amplification was carried out in all the patients and it was correlated with classic clinicopathological parameters, survival and recurrence pattern.

RESULTS

106 patients were included. HER2 expression was as follows: 71.7% HER2 negative, 21.7% HER2 equivocal and 6.6% HER2 positive, or with HER2 overexpression. 13.2% of patients (14/106) had HER2 amplification by DuoCISH. A significant association was seen between overexpression and amplification of HER2 (p < 0.001).HER2 positivity was associated with the intestinal subtype (p = 0.010) and a low grade of differentiation (p = 0.018). Likewise, HER2 was significantly associated with a worse prognosis: overall survival (OS) 32.3 months HER2 positive versus 93.9 months HER2 negative (HR 0.42; confidence interval 95% 0.18-0.93; p = 0.028); and the presence of distant metastasis without accompanying locoregional recurrence (p = 0.048).

CONCLUSION

HER2 status defines a subgroup with differentiated clinicopathological characteristics, worse prognosis and distant dissemination, without accompanying locoregional recurrence, in patients with resected gastric or GEJ adenocarcinoma operated on in a Western population.

Comparative analysis of HER2 copy number between plasma and tissue samples in gastric cancer using droplet digital PCR

In this study, we measured the human epidermal growth factor receptor 2 (HER2) copy number in both tissue and plasma samples of gastric cancer patients by using droplet digital polymerase chain reaction (ddPCR) method. Eighty gastric cancer patients were enrolled and both formalin-fixed and paraffin-embedded tissue and preoperative plasma samples were collected. HER2 status was determined by HER2 immunohistochemistry (IHC)/silver in situ hybridization (SISH) in tissue samples and ddPCR of the target gene HER2 and the reference gene eukaryotic translation initiation factor 2C, 1 in both tissue and plasma. The concordance rate of tissue HER2 status determined by IHC/SISH and HER2 ddPCR was 90.0% (72/80), and the sensitivity and specificity of tissue ddPCR were 85.0% and 95.0%, respectively. The concordance rate of plasma ddPCR and IHC/SISH was 63.8% (51/80). The sensitivity, specificity, positive predictive value, and negative predictive value of plasma HER2 ddPCR were 37.5%, 90.0%, 79.0%, and 59.0%, respectively. As HER2 measurement by tissue ddPCR showed a high concordance rate with HER2 status by IHC/SISH, it could replace tissue IHC/SISH testing in gastric cancer. These findings may contribute to the development of tissue and plasma HER2 testing that would be useful in daily practice.

Evaluation of the expression of the oncogen C-ERBB-2/HER2 in advanced gastric cancer cases from Costa Rica

Justification

The prevalence of gastric cancer (GC) with increased expression of the HER2 oncoprotein shows important variations worldwide. Incidence and mortality rates of GC in Costa Rica are among the highest in Latin America and the world; however, the prevalence of HER2-positive cases in this country is unknown. Evaluation of this parameter is important to decide the therapeutic approach for GC patients. The aim of this study was to provide an estimation of the prevalence of GC patients overexpressing the HER2 oncogene in Costa Rica.

Methods

The investigation was carried out in two phases. The first one consisted of a retrospective review of 331 clinical records of patients diagnosed with advanced or metastatic GC from January 2010 to January 2012 in four hospitals in Costa Rica. In the second phase, immunohistochemistry (IHC) and fluorescent in situ hybridisation (FISH) analyses were performed in formalin-fixed and paraffin-embedded (FFPE) surgical samples from 50 patients diagnosed with GC between 2012 and 2015.

Results

Of the 331 clinical files reviewed, the assessment of HER2 status was carried out in 62 patients (18.7%), of which only five (8%) were HER2-positive. In the 50 surgical specimens in which IHC and FISH analyses were performed, two of them (4%) presented overexpression and amplification of the HER2 oncogene.

Conclusion

This study suggests that the prevalence of GC cases overexpressing the HER2 oncogene in Costa Rica is less than 8%. This is the first attempt ever undertaken to estimate the prevalence of HER2-positivity in GC in Costa Rica.

Photothermal and gene therapy combined with immunotherapy to gastric cancer by the gold nanoshell-based system

BACKGROUND

The gastric cancer is the second most malignant tumor in the world. HER-2 is one of the key targets for the gastric cancer therapy. Anti-HER-2 antibodies like trastuzumab, exhibits the satisfactory therapeutic effect in clinical. However, the drug resistance problem limits its application.

METHOD

In this study, we develop a gold nanoshell (Gold Nanoshell) drug carrier for delivery and selective photo-thermal release of genes which target HER-2 and immunologic adjuvant CPG sequence in gastric tumor cells. The drug delivery system generated a multidimensional treatment strategy which includes gene-, immune- and photothermal-therapy.

RESULTS

The whole gold nanoshell drug delivery system exhibits the well gene transduction ability and combined treatment effect. Both in vitro and in vivo results demonstrate the multiple therapeutic effects of the drug delivery system is better than the monotherapy.

CONCLUSIONS

This study indicates the multiple combined therapy based on the gold nanoshell system would be a promising translational treatment for gastric cancer.

γ-Tocotrienol-Inhibited Cell Proliferation of Human Gastric Cancer by Regulation of Nuclear Factor-κB Activity

γ-Tocotrienol (γ-T3) exhibits the activity of anticancer via regulating cell signaling pathways. Nuclear factor-κB (NF-κB), one of the crucial pro-inflammatory factors, is involved in the regulation of cell proliferation, apoptosis, invasion, and migration of tumor. In the present study, NF-κB activity inhibited by γ-T3 was investigated in gastric cancer cells. Cell proliferation, NF-κB activity, active protein phosphatase type 2A (PP2A), and ataxia-telangiectasia mutated (ATM) protein were explored using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT), methylene blue, enzyme-linked immunosorbent assay (ELISA), malachite green, luciferase, and Western blotting assays. The effects of γ-T3 on tumor growth and the expression of NF-κB and PP2A proteins were also further examined by implanting human gastric cancer cells in a BALB/c nude mouse model. The results showed that γ-T3 significantly inhibited the cell proliferation and attenuated the NF-κB activity in vitro and in vivo. γ-T3 dramatically increased PP2A activity and protein expression, which suppressed ATM phosphorylation and its translocation to the cytoplasm in gastric cancer cells. Thus, our findings may provide mechanistic insight into effects of γ-T3 on the regulation of NF-κB activity by a PP2A-dependent mechanism and suggest that PP2A may serve as a molecular target for a potential chemopreventive agent.

Polyethylene glycol-conjugated HER2-targeted peptides as a nuclear imaging probe for HER2-overexpressed gastric cancer detection in vivo

BACKGROUND

The human epidermal growth factor receptor 2 (HER2) involved proliferation, angiogenesis, and reduced apoptosis in gastric cancer (GC), which is a common target for tumor therapy. HER2 is usually overexpressed in more than 15% GC patients, developing a reliable diagnostic tool for tumor HER2 detection is important. In this study, we attend to use polyethylene glycol (PEG) linked anti-HER2/neu peptide (AHNP-PEG) as a nuclear imaging agent probe for HER2 detection in GC xenograft animal model.

METHODS

The HER2 expression of human sera and tissues were detected in GC patients and normal subjects. GC cell lines NCI-N87 (high HER2 levels) and MKN45 (low HER2 levels) were treated with AHNP-PEG to assess the cell viability and HER2 binding ability. The NCI-N87 was treated with AHNP-PEG to observe the level and phosphorylation of HER2. The MKN45 and NCI-N87-induced xenograft mice were intravenous injection with fluorescence labeled AHNP-PEG for detecting in vivo fluorescence imaging properties and biodistribution. The AHNP-PEG was conjugated with diethylenetriaminopentaacetic acid (DTPA) for indium-111 labeling (¹¹¹In-DTPA-AHNP-PEG). The stability of was assessed in vitro. The imaging properties and biodistribution of ¹¹¹In-DTPA-AHNP-PEG were observed in NCI-N87-induced xenograft mice.

RESULTS

The serum HER2 (sHER2) levels in GC patients were significantly higher than the normal subjects. The sHER2 levels were correlated with the tumor HER2 levels in different stages of GC patients. The AHNP-PEG inhibited the cell growth and down-regulated HER2 phosphorylation in HER2-overexpressed human GC cells (NCI-N87) via specific HER2 interaction of cell surface. In addition, the GC tumor tissues from HER2-postive xenograft mice presented higher HER2 fluorescence imaging as compared to HER2-negative group. The HER2 levels in the tumor tissues were also higher than other organs in NCI-N87-induced xenograft mice. Finally, we further observed that the ¹¹¹In-DTPA-AHNP-PEG was significantly enhanced in tumor tissues of NCI-N87-induced xenograft mice compared to control.

CONCLUSIONS

These findings suggest that the sHER2 measurement may be as a potential tool for detecting HER2 expressions in GC patients. The radioisotope-labeled AHNP-PEG may be useful to apply in GC patients for HER2 nuclear medicine imaging.

Target-specific delivery of oxaliplatin to HER2-positive gastric cancer cells in vivo using oxaliplatin-au-fe3o4-herceptin nanoparticles

Gastric cancer is the fourth most common malignancy globally. In order to decrease the dosage and side effects of conventional chemotherapy, and achieve improved benefits from molecular targeted therapy, novel drug delivery systems were developed in the present study. Oxaliplatin-Au-Fe₃O₄-Herceptin^® acts as a dual-functional nanoparticles (NPs) conjugate and possesses the capability of human epithelial growth factor receptor 2 (HER2) targeting and oxaliplatin delivery. The 8-20 nm Au-Fe₃O₄ were synthesized by decomposing iron pentacarbonyl on the surfaces of Au NPs in the presence of oleic acid and oleylamine. Following being coated with polyethylene glycol, the NPs possessed a ζ-potential of 13.8±1.6 mV and were demonstrated to exhibit no cytotoxicity when Fe concentration is <100 µg/ml via an MTS assay. Mass spectrometry analysis detected a peak at m/z 148,000, and Nuclear Magnetic Resonance indicated peaks at δ 3.51 (8.00H, s, 3-H), 2.97-3.02 (3.80H, t, 2-H) and 2.72-2.76 (3.72H, t, 1-H) following successful loading with Herceptin and oxaliplatin probes. A drug release assay via dialysis cassettes demonstrated that 25% of the oxaliplatin was released at pH 8.0, however >58% was released at pH 6.0 following 4 h incubation, indicating its pH-dependent release characteristic. The active targeting feature of oxaliplatin-Au-Fe₃O₄-Herceptin was verified in a subcutaneous xenograft mouse model containing SGC-7901 cells via detecting aggregated low intensity in T₂-weighted magnetic resonance imaging, which was further confirmed by immunohistochemistry. Therefore, oxaliplatin-Au-Fe₃O₄-Herceptin is a promising multifunctional platform for simultaneous magnetic traceable and HER2 targeted chemotherapy for gastric cancer.

Pertuzumab and trastuzumab: the rationale way to synergy

It has now been 15 years since the HER2-targeted monoclonal antibody trastuzumab was introduced in clinical and revolutionized the treatment of HER2-positive breast cancer patients. Despite this achievement, most patients with HER2-positive metastatic breast cancer still show progression of their disease, highlighting the need for new therapies. The continuous interest in novel targeted agents led to the development of pertuzumab, the first in a new class of agents, the HER dimerization inhibitors. Pertuzumab is a novel recombinant humanized antibody directed against extracellular domain II of HER2 protein that is required for the heterodimerization of HER2 with other HER receptors, leading to the activation of downstream signalling pathways. Pertuzumab combined with trastuzumab plus docetaxel was approved for the first-line treatment of patients with HER2-positive metastatic breast cancer and is currently used as a standard of care in this indication. In the neoadjuvant setting, the drug was granted FDA-accelerated approval in 2013. Pertuzumab is also being evaluated in the adjuvant setting. The potential of pertuzumab relies in the dual complete blockade of the HER2/3 axis when administered with trastuzumab. This paper synthetises preclinical and clinical data on pertuzumab and highlights the mechanisms underlying the synergistic activity of the combination pertuzumab-trastuzumab which are essentially due to their complementary mode of action.

Integrative analysis of genome-wide gene copy number changes and gene expression in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) represents a genomically unstable cancer type with extensive copy number aberrations. The relationship of gene copy number alterations and subsequent mRNA levels has only fragmentarily been described. The aim of this study was to conduct a genome-wide analysis of gene copy number gains and corresponding gene expression levels in a clinically well annotated NSCLC patient cohort (n = 190) and their association with survival. While more than half of all analyzed gene copy number-gene expression pairs showed statistically significant correlations (10,296 of 18,756 genes), high correlations, with a correlation coefficient >0.7, were obtained only in a subset of 301 genes (1.6%), including KRAS, EGFR and MDM2. Higher correlation coefficients were associated with higher copy number and expression levels. Strong correlations were frequently based on few tumors with high copy number gains and correspondingly increased mRNA expression. Among the highly correlating genes, GO groups associated with posttranslational protein modifications were particularly frequent, including ubiquitination and neddylation. In a meta-analysis including 1,779 patients we found that survival associated genes were overrepresented among highly correlating genes (61 of the 301 highly correlating genes, FDR adjusted p<0.05). Among them are the chaperone CCT2, the core complex protein NUP107 and the ubiquitination and neddylation associated protein CAND1. In conclusion, in a comprehensive analysis we described a distinct set of highly correlating genes. These genes were found to be overrepresented among survival-associated genes based on gene expression in a large collection of publicly available datasets.

Detection and Significance of Human Epidermal Growth Factor Receptor 2 Expression in Gastric Adenocarcinoma

Background:

Human epidermal growth factor receptor 2 (HER2) is involved in the pathogenesis of several types of cancer, including gastric cancer. Overexpression of HER2 is noted in 10%–22.8% of gastric adenocarcinoma and its identification is of immense importance for management by targeted drugs. Detection of HER2 expression in gastric malignancies has not been undertaken previously in the local population.

Objective:

To ascertain HER2 immunohistochemical expression in gastric adenocarcinoma and its relationship with the anatomic location and histomorphology.

Materials and Methods:

A total of 47 cases of gastric adenocarcinoma diagnosed over 2 years constituted the study group. Clinical history, type of operation, gross morphology, and hematoxylin and eosin (H and E) stained sections were reviewed. Two paraffin blocks were selected, immunostain was performed using rabbit monoclonal HER2 antibody and Hoffmann scoring system was applied.

Results:

Most of gastric carcinomas occurred in male (42 cases), having a mean age of 53.6 years. A total of eight cases (17.1%) had expressed a score of 3+ HER2 positivity. All positivity was noted in intestinal type according to Lauren classification (25%) and none in diffuse type. All HER2 score of 3+ was noted in histological grade of well and moderately differentiated adenocarcinoma. Score 2+ was noted in seven cases, among them, only two were poorly differentiated gastric adenocarcinoma.

Conclusion:

HER2 overexpression was noticeably associated with an intestinal subtype, and well and moderately differentiated adenocarcinomas. Such cases of gastric adenocarcinoma are considered for targeted therapy with trastuzumab in the local population.

Gene Signal Distribution and HER2 Amplification in Gastroesophageal Cancer

Background: HER2 serves as an important therapeutic target in gastroesophageal cancer. Differences in HER2 gene signal distribution patterns can be observed at the tissue level, but how it influences the HER2 amplification status has not been studied so far. Here, we investigated the link between HER2 amplification and the different types of gene signal distribution.

Methods: Tumor samples from 140 patients with gastroesophageal adenocarcinoma where analyzed using the HER2 IQFISH pharmDx™ assay. Specimens covered non-amplified and amplified cases with a preselected high proportion of HER2 amplified cases. Based on the HER2/CEN-17 ratio, specimens were categorized into amplified or non-amplified. The signal distribution patterns were divided into homogeneous, heterogeneous focal or heterogeneous mosaic. The study was conducted based on anonymized specimens with limited access to clinicopathological data.

Results: Among the 140 analyzed specimens 83 had a heterogeneous HER2 signal distribution, with 62 being focal and 21 of the mosaic type. The remaining 57 specimens had a homogeneous signal distribution. HER2 amplification was observed in 63 of the 140 specimens, and nearly all (93.7%) were found among specimens with a heterogeneous focal signal distribution (p<0.0001). The mean HER2/CEN-17 ratio for the focal heterogeneous group was 8.75 (CI95%: 6.87 - 10.63), compared to 1.53 (CI95%: 1.45 - 1.61) and 1.70 (CI95%: 1.22 - 2.18) for the heterogeneous mosaic and homogeneous groups, respectively, (p<0.0001).

Conclusions: A clear relationship between HER2 amplification and the focal heterogeneous signal distribution was demonstrated in tumor specimens from patients with gastroesophageal cancer. Furthermore, we raise the hypothesis that the signal distribution patterns observed with FISH might be related to different subpopulations of HER2 positive tumor cells.

Development of a highly specific HER2 monoclonal antibody for immunohistochemistry using protein microarray chips

HER2 is an orphan receptor tyrosine kinase of the EGFR families and is considered to be a key tumor driver gene [1]. Breast cancer and gastric cancer with HER2 amplification can be effectively treated by its neutralizing antibody, Herceptin. In clinic, Immunohistochemistry (IHC) was used as the primary screening method to diagnose HER2 amplification [2]. However, recent evidence suggested that the frequently used rabbit HER2 antibody 4B5 cross reacted with another family member HER4 [3]. IHC staining with 4B5 also indicated that there was strong non-specific cytoplasmic and nuclear signals in normal gastric mucosal cells and some gastric cancer samples. Using a protein lysate array which covers 85% of the human proteome, we have confirmed that the 4B5 bound to HER4 and a nuclear protein ZSCAN18 besides HER2. The non-specific binding accounts for the unexpected cytoplasmic and nuclear staining of 4B5 of normal gastric epithelium. Finally, we have developed a novel mouse HER2 monoclonal antibody UMAB36 with similar sensitivity to 4B5 but only reacted to HER2 across the 17,000 proteins on the protein chip. In 129 breast cancer and 158 gastric cancer samples, UMAB36 showed 100% sensitivity and specificity comparing to the HER2 FISH reference results with no unspecific staining in the gastric mucosa layer. Therefore, UMAB36 could provide as an alternative highly specific IHC reagent for testing HER2 amplification in gastric cancer populations.

The application of nanoparticles in diagnosis and theranostics of gastric cancer

Gastric cancer is the fourth most common cancer and the second leading cause of cancer related death worldwide. For the diagnosis of gastric cancer, apart from regular systemic imaging, the locoregional imaging is also of great importance. Moreover, there are still other ways for the detecting of gastric cancer, including the early detection of gastric cancer by endoscopy, the detection of gastric-cancer related biomarkers and the detection of circulating tumor cells (CTCs) of gastric cancer. However, conventional diagnostic methods are usually lack of specificity and sensitivity. Nanoparticles provide many benefits in the diagnosis of gastric cancer. Besides, nanoparticles are capable of integrating the functions of diagnosis and treatment together (theranostics). In this paper, we reviewed the applications of nanoparticles in diagnosis and theranostics of gastric cancer in the above mentioned aspects.

Sex, Race, and Age Disparities in the Improvement of Survival for Gastrointestinal Cancer over Time

There have been notable improvements in survival over the past 2 decades for gastrointestinal (GI) cancer. However, the degree of improvement by age, race, and sex remains unclear. We analyzed data from 9 population-based cancer registries included in the SEER program of the National Cancer Institute (SEER 9) in 1990 to 2009 (n = 288,337). The degree of survival improvement over time by age, race, and sex was longitudinally measured. From 1990 to 2009, improvements in survival were greater for younger age groups. For patients aged 20 to 49 years and diagnosed from 2005 to 2009, adjusted HRs (95% CIs) were 0.74 (95% CI, 0.66-0.83), 0.49 (95% CI, 0.37-0.64), 0.69 (95% CI, 0.65-0.76), 0.62 (95% CI, 0.54-0.69), and 0.56 (95% CI, 0.42-0.76), for cancer of the stomach, small intestine, colon, rectum and anus, respectively, compared with the same age groups of patients diagnosed during 1990 to 1994. Compared with African Americans, whites experienced greater improvement in small intestinal and anal cancer survival. Female anal cancer and regional anal cancer patients experienced no improvement. Our data suggest that different improvement in survival in age, sex and race exists.

Design and Synthesis of Near-Infrared Peptide for in Vivo Molecular Imaging of HER2

We report the development, characterization, and validation of a peptide specific for the extracellular domain of HER2. This probe chemistry was developed for molecular imaging by using a structural model to select an optimal combination of amino acids that maximize the likelihood for unique hydrophobic and hydrophilic interactions with HER2 domain 3. The sequence KSPNPRF was identified and conjugated with either FITC or Cy5.5 via a GGGSK linker using Fmoc-mediated solid-phase synthesis to demonstrate flexibility for this chemical structure to be labeled with different fluorophores. A scrambled sequence was developed for control by altering the conformationally rigid spacer and moving both hydrophobic and hydrophilic amino acids on the C-terminus. We validated peptide specificity for HER2 in knockdown and competition experiments using human colorectal cancer cells in vitro, and measured a binding affinity of kd = 21 nM and time constant of k = 0.14 min(-1) (7.14 min). We used this peptide with either topical or intravenous administration in a preclinical model of colorectal cancer to demonstrate specific uptake in spontaneous adenomas and to show feasibility for real time in vivo imaging with near-infrared fluorescence. We used this peptide in immunofluorescence studies of human proximal colon specimens to evaluate specificity for sessile serrated and sporadic adenomas. Improved visualization can be used endoscopically to guide tissue biopsy and detect premalignant lesions that would otherwise be missed. Our peptide design for specificity to HER2 is promising for clinical translation in molecular imaging methods for early cancer detection.

Serum HER2 Is a Potential Surrogate for Tissue HER2 Status in Gastric Cancer: A Systematic Review and Meta-Analysis

Determining the expression level of human epidermal growth factor receptor 2 (HER2) in tumor tissue is of great importance for personalized therapy in gastric cancer. Although several studies have investigated whether serum HER2 can serve as a surrogate for tissue HER2 status, results have been inconsistent. We therefore performed a meta-analysis of published clinical studies in an attempt to address this problem. PubMed, Embase, Web of Science, the Cochrane Library and Science Direct were queried for eligible studies that could provide sufficient data to construct 2 × 2 contingency tables. The quality of the studies included in the meta-analysis was assessed in accordance with the revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) criteria. The pooled sensitivity, specificity and diagnostic odds ratio (DOR) were calculated for the eligible studies. The summary receiver operating characteristic (SROC) curve was constructed and the area under the SROC (AUSROC) was used to evaluate overall diagnostic performance. Eight studies comprising a total of 1170 participants were included in our meta-analysis. The pooled sensitivity, specificity and DOR were 0.39 (95% CI: 0.21–0.61), 0.98 (95% CI: 0.87–1.00), and 27 (95% CI: 9–81), respectively. The AUSROC was 0.77 (95% CI: 0.73–0.80) and Deeks funnel plot suggested the absence of publication bias (p = 0.91). Meta-regression analysis indicated that threshold effect was the main source of heterogeneity. Assays for evaluating serum HER2 levels are highly specific and demonstrate moderate diagnostic performance for HER2 tissue status in gastric cancer.

c-Met targeting in advanced gastric cancer: An open challenge

Despite significant improvements in systemic chemotherapy over the last two decades, the prognosis of patients with advanced gastric and gastroesophageal junction adenocarcinoma (GC) remains poor. Because of molecular heterogeneity, it is essential to classify tumors based on the underlying oncogenic pathways and to develop targeted therapies acting on individual tumors. High-quality research and advances in technology have contributed to the elucidation of molecular pathways underlying disease progression and have stimulated many clinical studies testing target therapies in an advanced disease setting. In particular, strong preclinical evidence for the aberrant activation of the HGF/c-Met signaling pathways in GC cancers exists. This review will cover the c-Met pathway, the mechanisms of c-Met activation and the different strategies of its inhibition. Next, we will focus on the current state of the art in the clinical evaluation of c-Met-targeted therapies and the description of ongoing randomized trials with the idea that in this disease, high quality translational research to identify and validate biomarkers is a priority task.

Emerging kinase inhibitors of the treatment of gastric cancer

INTRODUCTION

Gastric cancer (GC) is the fifth most common malignancy in the world. In the last years, for the first time in literature, the addition of a targeted therapy to standard chemotherapy has proved to prolong median overall survival. In this scenario, kinase inhibitors (KIs), smaller intracellular agents, could be an interesting and novel type of targeted treatment of metastatic GC both in first and further lines of therapy.

AREAS COVERED

Several KI have been evaluated in the preclinical setting. This review will underline the most relevant targeted pathways involved in GC tumorigenesis and disease progression including EGFR, VEGFR, c-MET, mTOR, fibroblast growth factor receptor, Src and Aurora kinases.

EXPERT OPINION

Despite the good results of TOGA, RAINBOW and REGARD trials about the addition of monoclonal antibodies to standard of care in GC, the addition of KI seems not to achieve comparable interesting results in management of GC. However, an improved patient selection before and during treatment according to molecular characteristics, as well as combination studies evaluating the synergistic effect of combination schedules of different KIs and standard chemotherapy, or KI plus KI or KI plus antibodies-based therapy may reveal interesting results and lead to understand mechanisms of multi-drug resistance.

Human epidermal growth factor receptor 2 testing in gastric and gastroesophageal junction adenocarcinomas: role of the gastroenterologist

Endoscopic biopsy sampling of a gastric or GEJ mass is no longer just for histologic diagnosis. The biopsy material may be used for ancillary IHC and/or DNA testing. When possible, multiple biopsy specimens for sampling different areas of the tumor should be obtained to provide the best opportunity to identify overexpression of HER2 and abnormalities in other genes/proteins that may be expressed in different areas of the tumor. Thorough sampling at the time of initial diagnosis may prevent the need for future endoscopic procedures for the sole purpose of obtaining additional tissue for biomarker studies. Communication and coordination with oncologists and pathologists is essential to ensure an appropriate HER2 evaluation is performed. In the coming age of targeted therapeutics, endoscopy may not only be used to obtain tissue for histology and biomarker evaluation but may also be used for the direct in vivo evaluation of biomarkers that guide therapy.

Recent advances in the HER2 targeted therapy of gastric cancer

Recent advances in molecular targeted therapies, including targeting human epidermal growth factor receptor 2 (HER2), had a major forward step in the therapy for gastric cancer patients. Application of HER2-targeted therapies, in particular trastuzumab in combination with chemotherapy in metastatic HER2-positive gastric cancers, resulted in improvements in response rates, time to progression and overall survival. Nevertheless, as with breast cancer, many patients with gastric cancer develop resistance to trastuzumab. Several promising therapies are currently being developed in combination with chemotherapy to increase the efficacy and overcome the cancer-resistance. Here we review the current overview of clinical application of agents targeting HER2 in gastric cancer. We also discuss the ongoing trials supporting the use of HER2-targeted agents combined with cytotoxic agents or other monoclonal antibodies.

Oncogenic alterations in ERBB2/HER2 represent potential therapeutic targets across tumors from diverse anatomic sites of origin

BACKGROUND

Targeted ERBB2/HER2 inhibitors are approved by the U.S. Food and Drug Administration for the treatment of breast, gastric, and esophageal cancers that overexpress or amplify HER2/ERBB2, as measured by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), respectively. Activating mutations in ERBB2 have also been reported and are predicted to confer sensitivity to these targeted agents. Testing for these mutations is not performed routinely, and FISH and IHC are not applied outside of these approved indications.

MATERIALS AND METHODS

We explored the spectrum of activating ERBB2 alterations across a collection of ∼ 7,300 solid tumor specimens that underwent comprehensive genomic profiling using next-generation sequencing. Results were analyzed for base substitutions, insertions and deletions, select rearrangements, and copy number changes.

RESULTS

Known oncogenic ERBB2 alterations were identified in tumors derived from 27 tissues, and ERBB2 amplification in breast, gastric, and gastroesophageal cancers accounted for only 30% of these alterations. Activating mutations in ERBB2 were identified in 131 samples (32.5%); amplification was observed in 246 samples (61%). Two samples (0.5%) harbored an ERBB2 rearrangement. Ten samples (2.5%) harbored multiple ERBB2 mutations, yet mutations and amplifications were mutually exclusive in 91% of mutated cases.

CONCLUSION

Standard slide-based tests for overexpression or amplification of ERBB2 would fail to detect the majority of activating mutations that occur overwhelmingly in the absence of copy number changes. Compared with current clinical standards, comprehensive genomic profiling of a more diverse set of tumor types may identify ∼ 3.5 times the number of patients who may benefit from ERBB2-targeted therapy.

Oncogenic alterations in ERBB2/HER2 represent potential therapeutic targets across tumors from diverse anatomic sites of origin

BACKGROUND

Targeted ERBB2/HER2 inhibitors are approved by the U.S. Food and Drug Administration for the treatment of breast, gastric, and esophageal cancers that overexpress or amplify HER2/ERBB2, as measured by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), respectively. Activating mutations in ERBB2 have also been reported and are predicted to confer sensitivity to these targeted agents. Testing for these mutations is not performed routinely, and FISH and IHC are not applied outside of these approved indications.

MATERIALS AND METHODS

We explored the spectrum of activating ERBB2 alterations across a collection of ∼ 7,300 solid tumor specimens that underwent comprehensive genomic profiling using next-generation sequencing. Results were analyzed for base substitutions, insertions and deletions, select rearrangements, and copy number changes.

RESULTS

Known oncogenic ERBB2 alterations were identified in tumors derived from 27 tissues, and ERBB2 amplification in breast, gastric, and gastroesophageal cancers accounted for only 30% of these alterations. Activating mutations in ERBB2 were identified in 131 samples (32.5%); amplification was observed in 246 samples (61%). Two samples (0.5%) harbored an ERBB2 rearrangement. Ten samples (2.5%) harbored multiple ERBB2 mutations, yet mutations and amplifications were mutually exclusive in 91% of mutated cases.

CONCLUSION

Standard slide-based tests for overexpression or amplification of ERBB2 would fail to detect the majority of activating mutations that occur overwhelmingly in the absence of copy number changes. Compared with current clinical standards, comprehensive genomic profiling of a more diverse set of tumor types may identify ∼ 3.5 times the number of patients who may benefit from ERBB2-targeted therapy.

Proteomic and metabolic prediction of response to therapy in gastric cancer

Several new treatment options for gastric cancer have been introduced but the prognosis of patients diagnosed with gastric cancer is still poor. Disease prognosis could be improved for high-risk individuals by implementing earlier screenings. Because many patients are asymptomatic during the early stages of gastric cancer, the diagnosis is often delayed and patients present with unresectable locally advanced or metastatic disease. Cytotoxic treatment has been shown to prolong survival in general, but not all patients are responders. The application of targeted therapies and multimodal treatment has improved prognosis for those with advanced disease. However, these new therapeutic strategies do not uniformly benefit all patients. Predicting whether patients will respond to specific therapies would be of particular value and would allow for stratifying patients for personalized treatment strategies. Metabolic imaging by positron emission tomography was the first technique with the potential to predict the response of esophago-gastric cancer to neoadjuvant therapy. Exploring and validating tissue-based biomarkers are ongoing processes. In this review, we discuss the status of several targeted therapies for gastric cancer, as well as proteomic and metabolic methods for investigating biomarkers for therapy response prediction in gastric cancer.

Human Epidermal Growth Factor Receptor 2 (HER2) in Cancers: Overexpression and Therapeutic Implications

Human epidermal growth factor receptor 2 (HER2) is a member of the epidermal growth factor receptor family having tyrosine kinase activity. Dimerization of the receptor results in the autophosphorylation of tyrosine residues within the cytoplasmic domain of the receptors and initiates a variety of signaling pathways leading to cell proliferation and tumorigenesis. Amplification or overexpression of HER2 occurs in approximately 15-30% of breast cancers and 10-30% of gastric/gastroesophageal cancers and serves as a prognostic and predictive biomarker. HER2 overexpression has also been seen in other cancers like ovary, endometrium, bladder, lung, colon, and head and neck. The introduction of HER2 directed therapies has dramatically influenced the outcome of patients with HER2 positive breast and gastric/gastroesophageal cancers; however, the results have been proved disappointing in other HER2 overexpressing cancers. This review discusses the role of HER2 in various cancers and therapeutic modalities available targeting HER2.

From conventional chemotherapy to targeted therapy: use of monoclonal antibodies (moAbs) in gastrointestinal (GI) tumors

In recent years, significant progress has been made in the diagnosis and treatment of gastrointestinal cancers. Researches and clinicians however are still faced with challenges, not the least is the detection and management of tumors with varied gene mutation status. Clarification of the molecular pathology of gastrointestinal cancers may improve treatment options as well as quality of life and the long-term survival of this patient class. Therefore, molecular-targeted therapies have emerged as clinically useful drugs for gastrointestinal cancers cure, and predictive biomarkers have been heralded as the way to develop the right drug for the right patient. Moving from such appealing molecular background, we wrote an overview of the main targeted therapies, with particular interest to monoclonal antibodies that have already been approved in clinical practice or are being tested in gastrointestinal cancers treatment.

Afatinib and its encapsulated polymeric micelles inhibits HER2-overexpressed colorectal tumor cell growth in vitro and in vivo

Colorectal cancer (CRC) is known as a common malignant neoplasm worldwide. The role of EGFR/HER2 in CRC is unclear. Afatinib is an irreversible EGFR/HER2 inhibitor. There were few studies of afatinib on CRC. Here, we investigated the protein levels/expressions of HER2 in sera and tumors from CRC patients and the therapeutic effect of afatinib on HER2-overexpressed CRC in vitro and in vivo. The increased HER2 levels were detected in the collected sera and tumors of patients with CRC. The serological HER2 levels were correlated with the tumor HER2 expressions in patients. Afatinib also inhibited the HER2-positive tumor cell growth and caused apoptosis in HER2-overexpressed human colorectal cancer HCT-15 cells but not in low HER2 expressed human gastric cancer MKN45 cells. In vivo study showed that afatinib reduced tumor growth in HER2-overexpressed xenografts. Moreover, afatinib-encapsulated micelles displayed higher cytotoxic activity in HCT-15 cells and were more effective for tumor growth suppression in HCT-15-induced tumor xenografts than afatinib performance alone. Taken together, these findings suggest that higher serum HER2 levels reflect the higher HER2 contents in tumors of CRC patients, and the improved afatinib-encapsulated micelles possess high therapeutic efficacy in HER2-overexpressed CRC in vitro and in vivo.

ImmunoPET and biodistribution with human epidermal growth factor receptor 3 targeting antibody ⁸⁹Zr-RG7116

The humanized monoclonal antibody with high affinity for the human epidermal growth factor receptor (HER) 3, RG7116, is a glycoengineered, IgG1 class antibody. By labeling RG7116 with zirconium-89 ((89)Zr) we aimed to visualize in vivo HER3 expression and study the biodistribution of this antibody in human tumor-bearing mice. Biodistribution of (89)Zr-RG7116 was studied in subcutaneously xenografted FaDu tumor cells (HER3-positive). Dose-dependency of (89)Zr-RG7116 organ distribution and specific tumor uptake was assessed by administering doses ranging from 0.05 to 10 mg/kg RG7116 to SCID/Beige mice. Biodistribution was analyzed at 24 and 144 h after injection. MicroPET imaging was performed at 1, 3, and 6 days after injection of 1.0 mg/kg (89)Zr-RG7116 in the FaDu, H441, QG-56 and Calu-1 xenografts with varying HER3 expression. The excised tumors were analyzed for HER3 expression. Biodistribution analyses showed a dose- and time-dependent (89)Zr-RG7116 tumor uptake in FaDu tumors. The highest tumor uptake of (89)Zr-RG7116 was observed in the 0.05 mg/kg dose group with 27.5%ID/g at 144 h after tracer injection. MicroPET imaging revealed specific tumor uptake of (89)Zr-RG7116 in FaDu and H441 models with an increase in tumor uptake over time. Biodistribution data was consistent with the microPET findings in FaDu, H441, QG56 and Calu-1 xenografts, which correlated with HER3 expression levels. In conclusion, (89)Zr-RG7116 specifically accumulates in HER3 expressing tumors. PET imaging with this tracer provides real-time non-invasive information about RG7116 distribution, tumor targeting and tumor HER3 expression levels.

Role of human epidermal growth factor receptor 2 in gastric cancer: biological and pharmacological aspects

Amplification of the human epidermal growth factor receptor 2 (HER2) gene and overexpression of the HER2 protein is found in 15%-20% of patients with gastric and gastroesophageal junction cancer. The degree of HER2 overexpression and amplification varies with the location of the carcinoma, with higher expression in the gastroesophageal and proximal parts compared to the distal parts of the stomach. Further, HER2 overexpression and amplification also seems to be related to the Lauren histological classification, with higher levels found in the intestinal phenotype compared to the diffuse and mixed types. The prognostic properties of HER2 overexpression and amplification are still under debate, but a large number of studies seem to indicate that HER2 is a negative prognostic factor. The usefulness of HER2 targeted therapy in gastric cancer was demonstrated in the ToGA trial, where HER2-positive patients with advanced gastric and gastroesophageal junction adenocarcinoma were randomized to receive 5-FU/capecitabine and cisplatin, either alone or in combination with trastuzumab. A statically significant gain in overall survival was seen in patients who received the combined treatment of trastuzumab and chemotherapy. Patients with a strong overexpression of the HER2 protein (IHC3+) specifically benefited from the treatment, with a median overall survival of 17.9 mo. As a consequence of the positive results of the ToGA trial, patients with advanced gastric or gastroesophageal junction adenocarcinoma are now routinely tested for HER2. The ToGA trial must be characterized as a landmark in the treatment of gastric cancer and it has paved the way for a number of new HER2 targeted compounds such as pertuzumab, ado-trastuzumab emtansine, lapatinib, afatinib, and dacomitinib, which are currently undergoing phase II and III clinical testing. Overall, this review will discuss the current status of HER2 in gastric and gastroesophageal junction cancer and the future direction in relation to HER2 target therapy.

Ten-year follow-up of a prospective trial for the targeted therapy of gastric cancer with the human monoclonal antibody PAT-SC1

The fully human monoclonal antibody PAT-SC1 is specific for an isoform of CD55 (decay-accelerating factor) designated CD55^PAT-SC1. This antigen is expressed in the majority (80%) of gastric cancers (GCs), and the antibody induces tumour cell-specific apoptosis in vitro as well as in vivo. PAT-SC1, therefore, has been deemed promising as a therapeutic agent. Here, we describe the results of an academic clinical study performed in a neoadjuvant setting with resectable GC patients. Patients undergoing treatment for GC between 1997 and 2001 were tested for CD55^PAT-SC1 expression. Fifty-one resectable patients that tested positively received a single administration of 20 mg PAT-SC1 48 h prior to surgery. They underwent standard surgery with either subtotal or total gastrectomy with bursectomy, omentectomy and a modified D2-lymphadenectomy, aimed at R0 resection. Primary endpoints of the present study were to evaluate side-effects of the PAT-SC1 antibody treatment and to evaluate histopathological effects such as tumour regression and induction of apoptosis. Long-term survival was a secondary endpoint. Administration of PAT-SC1 appeared safe with only reversible side-effects according to WHO grade I and II. Despite the low-dose of the antibody, 81.6% of the patients showed signs of increased apoptosis within the primary tumour and 60% showed signs of tumour cell regression. Comparison of the 10-year survival rates of the R0-resected CD55^PAT-SC1-positive patients treated with the PAT-SC1 antibody with a historical collective of R0-resected CD55^PAT-SC1-positive patients not treated with PAT-SC1 indicated a survival benefit in the treated patients. Furthermore, comparison of the patient survival of CD55^PAT-SC1-positive vs. CD55^PAT-SC1-negative groups suggested that CD55^PAT-SC1 antigen expression is an independent predictor of poor survival in a Cox regression analysis. Antibody PAT-SC1 may be a useful additive therapeutic agent in the treatment of patients with CD55^PAT-SC1-expressing GCs. In combination with radical standard surgery, PAT-SC1 given as an adjuvant or neoadjuvant immunotherapeutic agent induces apoptosis in tumour cells which may improve survival of these patients. Because of the human origin and its specific binding to the CD55^PAT-SC1 antigen, PAT-SC1 was well tolerated in this trial.

New advances in HER2 testing in gastric cancer

Gastric cancer is one of the most common malignancies and represents the second leading cause of cancer death worldwide. The ToGA trial has shown that the humanized anti-HER2 (human epidermal growth factor receptor-2) monoclonal antibody Trastuzumab is effective in prolonging survival in patients with HER2-positive carcinoma of the stomach and the gastroesophageal junction (GEJ). Trastuzumab in combination with chemotherapy can be considered as a new standard option for patients with HER2-positive advanced gastric or gastro-oesophageal junction cancer. Therefore, it is crucial to accurately screen patients with HER2-positive gastric cancer. This article mainly discusses the recent advances in HER2 testing in gastric cancer.

Intratumoral heterogeneous amplification of ERBB2 and subclonal genetic diversity in gastric cancers revealed by multiple ligation-dependent probe amplification and fluorescence in situ hybridization

A humanized monoclonal antibody against ERBB2 is used in neoadjuvant therapy for patients with gastric cancer. A critical factor in determining patient eligibility and predicting outcomes of this therapy is the intratumoral heterogeneity of ERBB2 amplification in gastric adenocarcinomas. The aims of this study are to assess the underlying mechanisms of intratumoral heterogeneity of ERBB2 amplification; to characterize the diversity of coamplified oncogenes such as EGFR, FGFR2, MET, MYC, CCND1, and MDM2; and to examine the usefulness of multiple ligation-dependent probe amplification (MLPA) in the semicomprehensive detection of these gene amplifications. A combined analysis of immunohistochemistry and fluorescence in situ hybridization revealed ERBB2-amplified cancer cells in 51 of 475 formalin-fixed, paraffin-embedded gastric adenocarcinomas. The fraction of amplification-positive cells in each tumor ranged from less than 10% to almost 100%. Intratumoral heterogeneity of ERBB2 amplification, defined as less than 50% of cancer cells positive for ERBB2 amplification, was found in 41% (21/51) of ERBB2-amplified tumors. The combined analysis of MLPA and fluorescence in situ hybridization revealed that ERBB2 was coamplified with EGFR in 7 tumors, FGFR2 in 1 tumor, and FGFR2 and MET in 1 tumor; however, the respective genes were amplified in mutually exclusive cells. Coamplified ERBB2 and MYC coexisted within single nuclei in 4 tumors, and one of these cases had suspected coamplification in the same amplicon of ERBB2 with MYC. In conclusion, the amplification status of ERBB2 and other genes can be obtained semicomprehensively by MLPA and could be useful to plan individualized molecularly targeted therapy against gastric cancers.