Role of HER2/neu in tumor progression and therapy

Progress of PD-1/PD-L1 inhibitor combination therapy in immune treatment for HER2-positive tumors

BACKGROUND

Patients with HER2-positive cancers often face a poor prognosis, and treatment regimens containing anti-HER2 have become the first-line treatment options for breast and gastric cancers. However, these approaches are faced with significant challenges in terms of drug resistance. Hence, it is crucial to explore precise treatment strategies aimed at improving survival outcomes.

ADVANCEMENTS IN TREATMENT

Over the past few years, there has been rapid advancement in the realm of tumor therapy, particularly with the swift progress of immune checkpoint inhibitors, including PD-1/PD-L1 inhibitors. They exert anti-tumor effects by disrupting immune-suppressive factors within the tumor microenvironment. However, monotherapy with PD-1/PD-L1 inhibitors has several limitations. Consequently, numerous studies have explored combinatorial immunotherapeutic strategies and demonstrated highly promising avenues of development.

OBJECTIVE

This article aims to review the clinical trials investigating PD-1/PD-L1 inhibitor combination therapy for HER2-positive tumors. Additionally, it provides a summary of ongoing trials evaluating the efficacy and safety of these combined treatments, with the intention of furnishing valuable insights for the clinical management of HER2-positive cancer.

CONCLUSION

Combinatorial immunotherapeutic strategies involving PD-1/PD-L1 inhibitors hold considerable promise in the treatment of HER2-positive tumors. Continued research efforts and clinical trials are warranted to elucidate optimal treatment regimens that maximize therapeutic benefits while minimizing adverse effects.

HER2-targeted therapies in cancer: a systematic review

Abnormal alterations in human epidermal growth factor receptor 2 (HER2, neu, and erbB2) are associated with the development of many tumors. It is currently a crucial treatment for multiple cancers. Advanced in molecular biology and further exploration of the HER2-mediated pathway have promoted the development of medicine design and combination drug regimens. An increasing number of HER2-targeted drugs including specific monoclonal antibodies, tyrosine kinase inhibitors (TKIs), and antibody-drug conjugates (ADCs) have been approved by the U.S. Food and Drug Administration. The emergence of ADCs, has significantly transformed the treatment landscape for various tumors, such as breast, gastric, and bladder cancer. Classic monoclonal antibodies and novel TKIs have not only demonstrated remarkable efficacy, but also expanded their indications, with ADCs in particular exhibiting profound clinical applications. Moreover the concept of low HER2 expression signifies a breakthrough in HER2-targeted therapy, indicating that an increasing number of tumors and patients will benefit from this approach. This article, provides a comprehensive review of the underlying mechanism of action, representative drugs, corresponding clinical trials, recent advancements, and future research directions pertaining to HER2-targeted therapy.

HER2/neu-based vaccination with li-Key hybrid, GM-CSF immunoadjuvant and trastuzumab as a potent triple-negative breast cancer treatment

PURPOSE

Constituting 15 to 20% of breast cancer cases, the triple-negative subtype lacks effective treatments as being less responsive to hormone-associated therapies. Alternatively, a more powerful immunotherapeutic vaccination can trigger immune recognition and destruction against breast cancer by incorporating oncological antigens such as human epidermal growth factor receptor 2 (HER2/neu). Currently, HER2/neu-based vaccines have finished three phases with breast cancer patients, in conjunction with granulocyte-macrophage colony-stimulating factor (GM-CSF) that was proven to be a promising vaccine adjuvant in other cancer trials previously.

METHODS

Completed HER2/neu-based vaccine trials with GM-CSF immunoadjuvants for breast cancer were summarised, and additionally, the article discussed prominent findings of vaccine effectiveness in triple-negative breast cancer, regarding li-Key hybrid in vaccine design and co-administration of anti-HER2/neu trastuzumab.

RESULTS

Nine clinical trials of three HER2/neu epitopes, one with li-Key hybrid, were analysed with or without the presence of trastuzumab. Immunological responses and minimal toxicities were observed in these epitopes, and disease-free survival was especially improved in the triple-negative population.

CONCLUSION

HER2/neu-based peptide vaccine is a safe and effective approach against breast cancer, and its benefits can be potentially furthered by combining the li-Key hybrid vaccine with targeted drugs and adjuvants selected to enhance cross-presentation for exogenous vaccine antigens. Graphical abstract was created with Biorender.com (license number: HA24UHRBV4 and FP24UHRGDD).

Circular RNAs with protein-coding ability in oncogenesis

As ubiquitously expressed transcripts in eukaryotes, circular RNAs (circRNAs) are covalently closed and lack a 5'-cap and 3'-polyadenylation (poly (A)) tail. Initially, circRNAs were considered non-coding RNA (ncRNA), and their roles as sponging molecules to adsorb microRNAs have been extensively reported. However, in recent years, accumulating evidence has demonstrated that circRNAs could encode functional polypeptides through the initiation of translation mediated by internal ribosomal entry sites (IRESs) or N6-methyladenosine (m6A). In this review, we collectively discuss the biogenesis, cognate mRNA products, regulatory mechanisms, aberrant expression and biological phenotypes or clinical relevance of all currently reported, cancer-relevant protein-coding circRNAs. Overall, we provide a comprehensive overview of circRNA-encoded proteins and their physiological and pathological functions.

Evaluation of the anti-tumor effects of an anti-Human Epidermal growth factor receptor 2 (HER2) monoclonal antibody in combination with CD11b+/Gr-1+ myeloid cells depletion using a recombinant peptibody in 4 T1-HER2 tumor model

INTRODUCTION

Clinical efficacy of Human Epidermal growth factor Receptor 2 (HER2) targeted strategies is limited due to impaired anti-tumor responses negatively regulated by immunosuppressive cells. We thus, investigated the inhibitory effects of an anti-HER2 monoclonal antibody (1 T0 mAb) in combination with CD11b⁺/Gr-1⁺ myeloid cells depletion in 4 T1-HER2 tumor model.

METHODS

BALB/c mice were challenged with human HER2-expressing 4 T1 murine breast cancer cell line. A week post tumor challenge, each mouse received 50 µg of a myeloid cells specific peptibody every other day, or 10 mg/kg of 1 T0 mAb two times a week, and their combination for two weeks. The treatments effect on tumor growth was measured by calculating tumor size. Also, the frequencies of CD11b⁺/Gr-1⁺ cells and T lymphocytes were measured by flow cytometry.

RESULTS

Peptibody treated mice indicated tumor regression and 40 % of the mice eradicated their primary tumors. The peptibody was capable to deplete notably splenic CD11b⁺/Gr-1⁺ cells as well as intratumoral CD11b⁺/Gr-1⁺ cells (P < 0.0001) and led to an increased number of tumor infiltrating CD8⁺ T cells (3.3 folds) and also that of resident tumor draining lymph nodes (TDLNs) (3 folds). Combination of peptibody and 1 T0 mAb resulted in enhanced expansion of tumor infiltrating CD4 + and CD8⁺ T cells which was associated with tumor eradication in 60 % of the mice.

CONCLUSIONS

Peptibody is able to deplete CD11b⁺/Gr-1⁺ cells and increase anti-tumoral effects of the 1 T0 mAb in tumor eradication. Thus, this myeloid population have critical roles in development of tumors and their depletion is associated with induction of anti-tumoral responses.

Scoring Systems for Immunohistochemistry in Urothelial Carcinoma

Immunohistochemistry is widely used in diagnostic and scientific analysis of urothelial carcinoma. Objective interpretation of staining results is mandatory for accuracy and comparability in diagnostic and therapeutic patient care as well as research.Herein we summarize and explain standardized microscopic evaluation and scoring approaches for immunohistochemical stainings. We focus on commonly used and generally feasible approaches for different cellular compartments and comment on their utility in diagnostics and research practice.

The Role of Tumor-Associated Antigen HER2/neu in Tumor Development and the Different Approaches for Using It in Treatment: Many Choices and Future Directions

The treatment of HER2-positive cancers has changed significantly over the past ten years thanks to a significant number of promising new approaches that have been added to our arsenal in the fight against cancer, including monoclonal antibodies, inhibitors of tyrosine kinase, antibody-drug conjugates, vaccination, and particularly, adoptive-T-cell therapy after its great success in hematological malignancies. Equally important is the new methodology for determining patients eligible for targeted HER2 therapy, which has doubled the number of patients who can benefit from these treatments. However, despite the initial enthusiasm, there are still several problems in this field represented by drug resistance and tumor recurrence that require the further development of new more efficient drugs. In this review, we discuss various approaches for targeting the HER2 molecule in cancer treatment, highlighting their benefits and drawbacks, along with the different mechanisms responsible for resistance to HER2-targeted therapies and how to overcome them.

Associations Between Serum Reproductive Hormone Concentrations and Hormonal Receptor Status Among Postmenopausal Chinese Women With Breast Cancer: An Observational Study

Background and Objectives

Reproductive hormones and receptors play crucial roles in breast cancer development and progression. The association between preoperative serum reproductive hormone levels and receptor status in postmenopausal women with breast cancer remains unclear. Therefore, this study investigated the relationship between serum reproductive hormone concentrations and patient characteristics and hormone receptor status among postmenopausal Chinese women with breast cancer.

Materials and Methods

The medical records of 352 postmenopausal breast cancer patients who underwent an operation between October 2007 and October 2010 at the Department of Breast Tumor Surgery of Zhejiang Cancer Hospital were retrospectively evaluated. Serum levels of reproductive hormones were measured before surgery by liquid-chromatography tandem mass spectrometry. Hormone receptor levels were measured by an immunohistochemical assay using a mouse monoclonal antibody. The associations between serum hormone concentrations and hormone receptors were investigated by analysis of covariance.

Results

In this patient cohort, the serum level of luteinizing hormone (LH) declined with PMP duration. The median LH concentration was significantly higher in patients within 5 years of PMP than that in patients with PMP duration exceeding 5 years (23 vs. 18.32 mIU/ml, P <.0001). Significantly more patients with strong estrogen receptor (ER) or progesterone receptor (PR) expression had postmenopausal durations of less than 5 years compared to those with postmenopausal durations greater than 5 years (103 vs. 61 cases, P = .019; 93 vs. 46 cases, P = .0005). While most patients either lacked (97.1%) or co-expressed (84.3%) ER and PR, some patients expressed either ER or PR alone. ER and PR expression were negatively associated with receptor-tyrosine kinase erbB-2 (HER2) expression in postmenopausal patients with breast cancer. Meanwhile, increased ER and PR expression were associated with decreased serum levels of LH or follicle-stimulating hormone (FSH).

Conclusion

Decreased serum LH and FSH levels were associated with increased ER and PR expressions and decreased HER2 expression in postmenopausal patients with breast cancer.

Bispecific antibody simultaneously targeting PD1 and HER2 inhibits tumor growth via direct tumor cell killing in combination with PD1/PDL1 blockade and HER2 inhibition

Immune checkpoint blockade has shown significant clinical benefit in multiple cancer indications, but many patients are either refractory or become resistant to the treatment over time. HER2/neu oncogene overexpressed in invasive breast cancer patients associates with more aggressive diseases and poor prognosis. Anti-HER2 mAbs, such as trastuzumab, are currently the standard of care for HER2-overexpressing cancers, but the response rates are below 30% and patients generally suffer relapse within a year. In this study we developed a bispecific antibody (BsAb) simultaneously targeting both PD1 and HER2 in an attempt to combine HER2-targeted therapy with immune checkpoint blockade for treating HER2-positive solid tumors. The BsAb was constructed by fusing scFvs (anti-PD1) with the effector-functional Fc of an IgG (trastuzumab) via a flexible peptide linker. We showed that the BsAb bound to human HER2 and PD1 with high affinities (EC₅₀ values were 0.2 and 0.14 nM, respectively), and exhibited potent antitumor activities in vitro and in vivo. Furthermore, we demonstrated that the BsAb exhibited both HER2 and PD1 blockade activities and was effective in killing HER2-positive tumor cells via antibody-dependent cellular cytotoxicity. In addition, the BsAb could crosslink HER2-positive tumor cells with T cells to form PD1 immunological synapses that directed tumor cell killing without the need of antigen presentation. Thus, the BsAb is a new promising approach for treating late-stage metastatic HER2-positive cancers.

Heregulin Activity Assays for Residual Testing of Cell Therapy Products

Background

Heregulin is a ligand for the protooncogene product ErbB/HER that acts as  a key mitogenic factor for human Schwann cells (hSCs). Heregulin is required for sustained hSC growth in vitro but must be thoroughly removed before cell collection for transplantation due to potential safety concerns. The goal of this study was to develop simple cell-based assays to assess the effectiveness of heregulin addition to and removal from aliquots of hSC culture medium. These bioassays were based on the capacity of a β1-heregulin peptide to elicit ErbB/HER receptor signaling in adherent ErbB2+/ErbB3+ cells.

Results

Western blotting was used to measure the activity of three different β1-heregulin/ErbB-activated kinases (ErbB3/HER3, ERK/MAPK and Akt/PKB) using phospho-specific antibodies against key activating residues. The duration, dose-dependency and specificity of β1-heregulin-initiated kinase phosphorylation were investigated, and controls were implemented for assay optimization and reproducibility to detect β1-heregulin activity in the nanomolar range. Results from these assays showed that the culture medium from transplantable hSCs elicited no detectable activation of the aforementioned kinases in independent rounds of testing, indicating that the implemented measures can ensure that the final hSC product is devoid of bioactive β1-heregulin molecules prior to transplantation.

Conclusions

These assays may be valuable to detect impurities such as undefined soluble factors or factors for which other biochemical or biological assays are not yet available. Our workflow can be modified as necessary to determine the presence of ErbB/HER, ERK, and Akt activators other than β1-heregulin using native samples, such as fresh isolates from cell- or tissue extracts in addition to culture medium.

Nucleic Acid Tests for Clinical Translation

Nucleic acids, including deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), are natural biopolymers composed of nucleotides that store, transmit, and express genetic information. Overexpressed or underexpressed as well as mutated nucleic acids have been implicated in many diseases. Therefore, nucleic acid tests (NATs) are extremely important. Inspired by intracellular DNA replication and RNA transcription, in vitro NATs have been extensively developed to improve the detection specificity, sensitivity, and simplicity. The principles of NATs can be in general classified into three categories: nucleic acid hybridization, thermal-cycle or isothermal amplification, and signal amplification. Driven by pressing needs in clinical diagnosis and prevention of infectious diseases, NATs have evolved to be a rapidly advancing field. During the past ten years, an explosive increase of research interest in both basic research and clinical translation has been witnessed. In this review, we aim to provide comprehensive coverage of the progress to analyze nucleic acids, use nucleic acids as recognition probes, construct detection devices based on nucleic acids, and utilize nucleic acids in clinical diagnosis and other important fields. We also discuss the new frontiers in the field and the challenges to be addressed.

Introduction of hsa-miR-512-3p as a new regulator of HER2 signaling pathway in breast cancer

PURPOSE

Dysregulation of HER2 signaling pathway in breast cancer is well documented. Our bioinformatics analysis predicted hsa-miR-512-3p (miR-512-3p) as a bona fide regulator of HER2 as well as HER3, PIK3R2, and AKT1 genes. Then, we intended to examine the effect of miR-512-3p on the predicted target genes that are involved in HER2 signaling pathway.

METHODS AND RESULTS

RT-qPCR results indicated lower expression of miR-512-3p in breast cancer specimens, compared to their normal pairs. Overexpression of miR-512-3p resulted in HER2, HER3, PIK3R2, and AKT1 gene downregulation, detected by RT-qPCR and the result was confirmed by western analysis and ELIZA test against p-AKT, BAX, FADD, and HER2 proteins in SKBR3 cells, respectively. Then, dual-luciferase assay supported the direct interaction of miR-512-3p with 3'UTR sequences of HER2, HER3, PIK3R2, and AKT1 target genes. When miR-512-3p was overexpressed, BAX/BCL2 expression ratio and proportion of sub-G1 cell population were increased in transfected SKBR3 cells, detected by RT-qPCR and flow cytometry, respectively. These results were consistent with the decreased viability of transfected cells, documented by MTT assay. In addition, results were consistent with the upregulation of BAX, BAK, BOK, PTEN, P53, and P21 genes and downregulation of CCND1 gene in SKBR3 cells. Although the overexpression of miR-512 resulted in cell cycle arrest at Sub-G1 stage in MDA-MB-231 cells, this effect seemed independent of targeting HER2, HER3, PIK3R2, and AKT1 target genes.

CONCLUSION

Overall, results indicated that miR-512-3p acts as a cell-type-specific tumor suppressor, through targeting HER2, HER3, PIK3R2, and AKT1 transcripts. These results suggest miR-512-3p as a potential candidate marker for breast cancer diagnosis.

UCNP-based Photoluminescent Nanomedicines for Targeted Imaging and Theranostics of Cancer

Theranostic approach is currently among the fastest growing trends in cancer treatment. It implies the creation of multifunctional agents for simultaneous precise diagnosis and targeted impact on tumor cells. A new type of theranostic complexes was created based on NaYF₄: Yb,Tm upconversion nanoparticles coated with polyethylene glycol and functionalized with the HER2-specific recombinant targeted toxin DARPin-LoPE. The obtained agents bind to HER2-overexpressing human breast adenocarcinoma cells and demonstrate selective cytotoxicity against this type of cancer cells. Using fluorescent human breast adenocarcinoma xenograft models, the possibility of intravital visualization of the UCNP-based complexes biodistribution and accumulation in tumor was demonstrated.

Multifunctional Complexes Based on Photoluminescent Upconversion Nanoparticles for Theranostics of the HER2-Positive Tumors

Combining diagnostic and therapeutic functions in one agent is a promising strategy in the development of personalized approaches to the treatment of cancer. The opportunity to combine diagnostics and therapy appeared with the development of nanobiotechnologies and was realized in the concept of theranostics. To date, a number of promising agents based on nanomaterials capable of diagnosing, targeted therapeutic effects, and monitoring the response of tumor cells were obtained within the approach of theranostics. In this work, a new type of theranostic complexes based on upconversion nanoparticles coated with polyethylene glycol and functionalized with the DARPin-LoPE recombinant targeted toxin was developed. Selective binding of complexes to human breast adenocarcinoma cells overexpressing the HER2 receptor and specific toxicity to them were shown.

Oncogenic Potential of Bisphenol A and Common Environmental Contaminants in Human Mammary Epithelial Cells

There is an ample epidemiological evidence to support the role of environmental contaminants such as bisphenol A (BPA) in breast cancer development but the molecular mechanisms of their action are still not fully understood. Therefore, we sought to analyze the effects of three common contaminants (BPA; 4-tert-octylphenol, OP; hexabromocyclododecane, HBCD) on mammary epithelial cell (HME1) and MCF7 breast cancer cell line. We also supplied some data on methoxychlor, MXC; 4-nonylphenol, NP; and 2-amino-1-methyl-6-phenylimidazo [4–b] pyridine, PhIP. We focused on testing the prolonged (two months) exposure to low nano-molar concentrations (0.0015–0.0048 nM) presumed to be oncogenic and found that they induced DNA damage (evidenced by upregulation of pH2A.X, pCHK1, pCHK2, p-P53) and disrupted the cell cycle. Some agents induced epigenetic (methylation) changes of tumor suppressor genes TIMP3, CHFR, ESR1, IGSF4, CDH13, and GSTP1. Obviously, the accumulation of these molecular alterations is an essential base for cancer development. Consistent with this, we observed that these agents increased cellular invasiveness through collagen. Cellular abilities to form colonies in soft agar were increased for MCF7. Toxic agents induced phosphorylation of protein kinase such as EGFR, CREB, STAT6, c-Jun, STAT3, HSP6, HSP27, AMPKα1, FAK, p53, GSK-3α/β, and P70S6 in HME1. Most of these proteins are involved in potential oncogenic pathways. Overall, these data clarify the molecular alterations that can be induced by some common environmental contaminants in mammary epithelial cells which could be a foundation to understand environmental carcinogenesis.

Comparative anti-proliferative effects of potential HER2 inhibitors on a panel of breast cancer cell lines

BACKGROUND

Breast cancer is one of the most lethal types of cancer in women worldwide. The human epidermal growth factor receptor 2 (HER2) is considered as a validated target in breast cancer therapy. Previously, we have used quantitative structure activity relationship QSAR equations and their associated pharmacophore models to screen for new promising HER2 structurally diverse inhibitory leads which were tested against HER2-overexpressing SKOV3 ovarian cancer cell line.

OBJECTIVE

In this study, we sought to explore the effect of most active ligands against different normal and breast cancer cell lines that represent different breast cancer subtypes with distinguished expression levels in HER2 and HER1.

METHODS

We have tested the promising compounds against SKBR3, MDA-MB-231, MCF7, human fibroblast, and MCF10 cell lines. To understand the inhibitory effects of the active ligands against HER2 over expressed breast cancer cell lines, all inhibitors and the control compound, lapatinib, were docked into the active site of HER2 enzyme performed using Ligand Fit docking engine and PMF scoring function.

RESULTS

Five ligands exhibited promising results with relatively low IC₅₀ values on cells that amplify HER2 and high IC₅₀ on those that do not express such a receptor. The most potent compound (compound 13) showed an IC₅₀ of 0.046 µM. To test their toxicity against normal cells, the active compounds were tested against both normal fibroblast and normal breast cancer cell MCF-10 and relatively high IC₅₀ values were scored. The IC₅₀ values on HER2 over-expressed breast cancer and normal fibroblast cells provided a promising safety index. Docking results showed the highest similarity in the binding site between the most active ligand and the lapatinib.

CONCLUSION

Our pharmacophore model resulted in a high potent ligand that shows high potency against HER2 positive breast cancer and relatively low toxicity towards the normal human cells.

Analysis of HER-2/neu Receptor Expression and the Level of Neuronal Apoptosis in HER-2/neu Transgenic Mice during Aging

We studied neuronal death in the sensorimotor cortex, hippocampus, and supraoptic and paraventricular nuclei of the hypothalamus and dynamics of HER-2/neu expression in late ontogenesis in young and old transgenic HER-2/neu mice. Wild-type FVB/N mice served as the control. The intensity of apoptosis (TUNEL) and HER-2/neu expression (Western blotting) in the same brain regions were measured. HER-2/neu was detected in the cortex, hippocampus, and hypothalamus of transgenic and wild-type mice, and its expression increased with age. The effect of HER-2/neu on the intensity of cell death in various brain regions depended on the stage of ontogenesis and animal genotype. Enhanced expression of HER-2/neu determines low rate of cell death in the studied brain regions during pathological ageing.

Recognition of HER2 expression in hepatocellular carcinoma and its significance in postoperative tumor recurrence

Background

The ERBB2 oncogene hypothesis is challenged in hepatocellular carcinoma (HCC) with the conflicting evidences of human epidermal growth factor receptor 2 (HER2) overexpression. HER2 could be a new target as a treatment option for HCC as well as tumor recurrence after surgery. HER2 in HCC biology needs further explorations.

Methods

Clinical and mRNA data of HCC patients were obtained from TCGA HCC cohort, GSE89377 and GSE115018. Western Blotting and immunohistochemistry were employed to test expression of HER2, E‐cadherin, and Vimentin. In HepG2, JM1, HER2‐transfected McA cells, and TGF‐β cocultured JM1 cells, HCC biology, including cell survival, proliferation, and epithelial‐to‐mesenchymal transition (EMT) phenotypes were evaluated.

Results

ERBB2 mRNA amplification was found in HCC datasets, and its expression was downregulated in high grade HCC with a worse overall survival. HER2 overexpression was identified in H4IIE, HepG2, JM1 cells, and 82% (14/17) HCC samples, and tumor stage was correlated with expression of HER2, E‐cadherin, and Vimentin (P < 0.05). Trastuzumab with the high concentrations suppressed proliferation of HER2‐positive hepatoma cells (P < 0.05); in the coculture model to induce EMT of JM1 cells, HER2 expression increased with downregulated E‐cadherin and upregulated Vimentin. Trastuzumab intravenous injection inhibited in vivo tumor size and metastases (P < 0.05). Signal analysis revealed that HER2 functioned through upregulation of β‐catenin and inhibition of SMAD3.

Conclusion

HER2 expression pattern is linked with tumor stage and overall survival; the transforming function of HER2 is found more relevant through β‐catenin and SMAD3. HER2‐targeted treatment is recommended to suppress the HER2‐mediated tumor growth during postoperative liver regeneration.

First-in-human phase 0 study of 111In-CHX-A"-DTPA trastuzumab for HER2 tumor imaging

Introduction:

Tumors over-expressing the human epithelial receptor 2 (HER2) or exhibiting amplification or mutation of its proto-oncogene have a poorer prognosis. Using trastuzumab and/or other HER2 targeted therapies can increase overall survival in patients with HER2(+) tumors making it critical to accurately identify patients who may benefit. We report on a Phase 0 study of the imaging agent, ¹¹¹In-CHX-A”-DTPA trastuzumab, in patients with known HER2 status to evaluate its safety and biodistribution and to obtain preliminary data regarding its ability to provide an accurate, whole-body, non-invasive means to determine HER2 status.

Methods:

¹¹¹In-CHX-A”-DTPA trastuzumab was radiolabeled on-site and slowly infused into 11 patients who underwent single (n=5) or multiple (n=6) ɣ-camera (n=6) and/or SPECT (n=8) imaging sessions.

Results:

No safety issues were identified. Visual and semi-quantitative imaging data were concordant with tissue HER2 expression profiling in all but 1 patient. The biodistribution showed intense peak liver activity at the initial imaging timepoint (3.3h) and a single-phase clearance fit of the average time-activity curve (TAC) estimated t_1/2=46.9h (R²=0.97; 95%CI 41.8 to 53h). This was followed by high gastrointestinal (GI) tract activity peaking by 52h. Linear regression predicted GI clearance by 201.2h (R² =0.96; 95%CI 188.5 to 216.9h). Blood pool had lower activity with its maximum on the initial images. Non-linear regression fit projected a t_1/2=34.2h (R² =0.96; 95%CI 25.3 to 46.3h). Assuming linear whole-body clearance, linear regression projected complete elimination (x-intercept) at 256.5hr (R²=0.96; 95%CI 186.1 to 489.2h).

Conclusion:

¹¹¹In-CHX-A”-DTPA trastuzumab can be safely imaged in humans. The biodistribution allowed for visual and semiquantitative analysis with results concordant with tissue expression profiling in 10 of 11 patients. Advances in Knowledge and Implications for Patient Care Using readily available components and on-site radiolabeling ¹¹¹In-CHX-A”-DTPA trastuzumab SPECT imaging may provide an economical, non-invasive means to detect HER2 over-expression.

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.

Lead exposure and plasma mRNA expression in ERBB2 gene

Epidemiologic data for carcinogenicity in those exposed to lead (Pb) suggests relations with cancers although the totality of the evidence is inconsistent. Alterations in the expression of ERBB receptors have been studied during the development and malignant transformation of different kinds of human tumors where they induce proliferation, angiogenesis and metastasis generation. Relevant clinical data demonstrate the role of ERBB2 receptors in the development and malignancy of human cancers. Therefore, the objective of the present investigation is to give more information on the link between plasma mRNA expression in ERBB2 gene and lead blood levels in a healthy population. Blood samples, socio‑demographic, exposure and health data were obtained from 48 healthy men. Real‑time polymerase chain reaction assays were performed to detect ERBB2 gene transcripts, ΔΔCt method was used to quantify gene expression. Pb blood level was assayed using high‑resolution sector field inductively coupled mass spectrometry and is expressed in µg/dl. Plasma mRNA expression in ERBB2 gene was 6.44±3.07 ΔΔCt; Pb blood levels was 16.07±6.74 µg/dl. Regression analysis revealed a significant association (r2=0.5345; p<0.0001) between Pb levels and mRNA expression in ERBB2. So far, it has still not been established if the expression of ERBB2 receptors is influenced by Pb exposure. On the base of the above reported data, we believe an in vitro study might be useful, to understand the molecular mechanisms implicated.

Enhanced and long term immunogenicity of a Her-2/neu multi-epitope vaccine conjugated to the carrier CRM197 in conjunction with the adjuvant Montanide

Background

We previously identified three short single peptides (P4, P6 and P7) representing different B-cell epitopes on the extracellular domain of Her-2/neu for a vaccine that was tested in a phase-I clinical trial. Here we describe the improvement of the multi peptide vaccine by fusing the single peptides to a hybrid peptide P467.

Methods

After coupling to either virosomes or to diphtheria toxoid CRM197 (CRM), the hybrid peptide was tested in different concentrations in combination with either Montanide or Aluminium hydroxide (Alum) in preclinical studies.

Results

Already low amount (10 μg) of P467 conjugated to CRM led to faster onset of high antibody levels compared to the P467-virosome. The formulation P467-CRM-Montanide induced higher serum IgG antibody titers, compared with P467-CRM-Alum, as examined by ELISA using recombinant Her-2/neu or Her-2/neu natively expressed on the tumor cell line SK-BR-3. Compared to P467-CRM-Alum, higher in vitro production of IL-2 and IFNγ in the Montanide-immunized mice was induced after re-stimulation of splenocytes with CRM but also with P467, indicating a clear Th1-biased response. In contrast to the single B cell peptides, the hybrid peptide led to T cell proliferation and cytokine production as CD4 T cell epitopes were generated in the fusion region of the single peptides P4 and P6 or P6 and P7. Additionally, a significantly higher proportion IFNγ-producing CD8+ T cells was found in the P467-CRM-Montanide immunized mice, probably by Montanide-driven bystander activation. Importantly, anti-P467 IgG antibodies exhibited anti-tumor properties and the combination of anti-P467 specific IgG with Herceptin® was found to inhibit the proliferation of Her-2/neu-overexpressing cell line SK-BR-3 in a significantly higher capacity than Herceptin® alone.

Conclusions

Fusion of the B cell peptides has led to additional generation of CD4 T cell epitopes, and this P467-multi epitope vaccine was found to induce polyclonal antibody responses with anti-proliferative capacity against Her-2/neu. The hybrid vaccine together with Montanide induced higher and long-lasting antibody levels, Th1-biased cellular responses being superior to vaccination with the single B cell peptides. This vaccine formulation is now planned to be evaluated in a phase Ib/II study in Her-2/neu overexpressing cancer patients.

SAR and QSAR study on the bioactivities of human epidermal growth factor receptor-2 (HER2) inhibitors

In this paper, structure-activity relationship (SAR, classification) and quantitative structure-activity relationship (QSAR) models have been established to predict the bioactivity of human epidermal growth factor receptor-2 (HER2) inhibitors. For the SAR study, we established six SAR (or classification) models to distinguish highly and weakly active HER2 inhibitors. The dataset contained 868 HER2 inhibitors, which was split into a training set including 580 inhibitors and a test set including 288 inhibitors by a Kohonen's self-organizing map (SOM), or a random method. The SAR models were performed using support vector machine (SVM), random forest (RF) and multilayer perceptron (MLP) methods. Among the six models, SVM models obtained superior results compared with other models. The prediction accuracy of the best model (model 1A) was 90.27% and the Matthews correlation coefficient (MCC) was 0.80 on the test set. For the QSAR study, we chose 286 HER2 inhibitors to establish six quantitative prediction models using MLR, SVM and MLP methods. The correlation coefficient (r) of the best model (model 4B) was 0.92 on the test set. The descriptors analysis showed that HAccN, lone pair electronegativity and π electronegativity were closely related to the bioactivity of HER2 inhibitors.

Prognostic value of HER2 status in bladder transitional cell carcinoma revealed by both IHC and BDISH techniques

BACKGROUND

Her2/neu is an oncogene that plays an important role in the pathogenesis of many cancer types. In bladder carcinoma (BC), the clinical significance of Her2/neu status remains under-investigated and poorly linked to the patients' clinic-pathological features and survival status. Thus, the current study was conducted to assess Her2/neu status in a cohort of patients' in Saudi Arabia, and to explore its prognostic value in BC.

METHODS

A total of 160 consent patients of transitional cell carcinoma (TCC) of bladder were arranged on a tissue microarray (TMA) and stained by immunohistochemistry (IHC) and bright-field dual in situ hybridization (BDISH) methods. The intensity of Her2/neu protein receptor immunostaining was evaluated, correlated to Her2/neu gene amplification status in TCC and assessed for potential clinical value by correlation measures.

RESULTS

IHC data demonstrated that Her2/neu protein is expressed in 60 % (2+ and 3+) of our TCC patient's cohort from Saudi Arabia. Her2/neu gene amplification is detected in 25 % by BDISH. There was a strong association between Her2/neu protein levels and lymph node invasion (p = 0.04), tumor stage (p = 0.002), vascular invasion and borderline significance with distant metastasis (p = 0.07). Amplification of Her2/neu gene was associated with tumor grade (p = 0.03) and poor disease-specific survival (p = 0.02), in that, patients with non-amplified Her2/neu gene live longer. Interestingly, there was a reasonable concordance rate (71 %) between IHC and BDISH data in the analyzed cohort.

CONCLUSION

The study showed that 25 % of our patients' cohort has Her2/neu over-expression. This Her2/neu (over-expression/amplification) status was concordant using either IHC or BDISH and significantly associated with disease aggressiveness and poor outcome. These findings suggested a potential impact of anti-Her2 targeted therapy in the treatment of bladder cancer with amplified/overexpressed HER2 that needs further investigation.

ERK1 and ERK2 Map Kinases: Specific Roles or Functional Redundancy?

The MAP kinase signaling cascade Ras/Raf/MEK/ERK has been involved in a large variety of cellular and physiological processes that are crucial for life. Many pathological situations have been associated to this pathway. More than one isoform has been described at each level of the cascade. In this review we devoted our attention to ERK1 and ERK2, which are the effector kinases of the pathway. Whether ERK1 and ERK2 specify functional differences or are in contrast functionally redundant, constitutes an ongoing debate despite the huge amount of studies performed to date. In this review we compiled data on ERK1 vs. ERK2 gene structures, protein sequences, expression levels, structural and molecular mechanisms of activation and substrate recognition. We have also attempted to perform a rigorous analysis of studies regarding the individual roles of ERK1 and ERK2 by the means of morpholinos, siRNA, and shRNA silencing as well as gene disruption or gene replacement in mice. Finally, we comment on a recent study of gene and protein evolution of ERK isoforms as a distinct approach to address the same question. Our review permits the evaluation of the relevance of published studies in the field especially when measurements of global ERK activation are taken into account. Our analysis favors the hypothesis of ERK1 and ERK2 exhibiting functional redundancy and points to the concept of the global ERK quantity, and not isoform specificity, as being the essential determinant to achieve ERK function.

The role of MAPK signaling pathway in the Her-2-positive meningiomas

Meningiomas are common types of adult nerve system tumors. Although most cases are considered benign, due to its high rate of recurrence and easy malignant progression to anaplastic meningioma they present a puzzle for the current treatment. The HER-2 oncogene has important value for meningioma cells development and progression. So far, little is known about the effect on the exact underlying signal pathway and molecular mechanisms of HER-2-positive meningioma cells. The goal of the present study was to determine the effects of HER-2 gene and possible involvement of MAPK signal pathway in human malignant meningioma. We applied q-PCR analysis, immunofluorescence (IF) staining, western blot analysis, animal model, MAPK inhibition, MTT assay and cell invasion analysis for the investigation. The results demonstrated that the downregulation of the expression of HER-2 significantly inhibited cell motility and proliferation of human meningioma cells in vivo. Accordingly, in the HER-2-overexpression meningioma cells with the inhibition of ERK1/2, ERK5, JNK, in the cells with the ERK1/2, ERK5 inhibition, protein expression was markedly suppressed as well as the cell proliferation resistance. No difference was observed in the HER-2-overexpression meningioma cells with the inhibition of JNK. These findings suggest that HER-2 gene can affect the proliferation ability of human meningioma cells in vivo and MAPK signal pathway may contribute to the carcinogenesis and development of human meningiomas combinating with HER-2.

Type II cGMP-dependent protein kinase directly inhibits HER2 activation of gastric cancer cells

Our previous study demonstrated that type II cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG II) inhibited epidermal growth factor (EGF)-induced phosphorylation/activation of epidermal growth factor receptor (EGFR). Since human epidermal growth factor receptor 2 (HER2) has a similar molecular structure to EGFR, the present study was designed to investigate whether PKG II also inhibits HER2 activation. The human gastric cancer cell line HGC‑27 was infected with an adenoviral construct encoding cDNA of PKG II (Ad‑PKG II) to increase the expression of PKG II and treated with 8‑(4‑chlorophenylthio)guanosine‑3',5'‑cyclic monophosphate (8‑pCPT‑cGMP) to activate the kinase. Western blotting was performed to detect the tyrosine and serine/threonine phosphorylation of HER2. Co‑immunoprecipitation was performed in order to determine the binding between PKG II and HER2. In addition, a QuikChange Lightning Site‑Directed Mutagenesis kit was used to mutate threonine 686 of HER2 to glutamic acid or alanine. The results demonstrated that EGF treatment increased the tyrosine phosphorylation (activation) of HER2. Increasing the PKG II activity of HGC‑27 cells through infection with Ad‑PKG II and stimulation with 8‑pCPT‑cGMP inhibited the EGF‑induced tyrosine phosphorylation/activation of HER2. PKG II bound directly with HER2 and caused phosphorylation of threonine 686. When threonine 686 of HER2 was mutated to alanine, which could not be phosphorylated by PKG II, the inhibitory effect of PKG II on the activation of HER2 was eradicated. When threonine 686 of HER2 was mutated to glutamic acid, which mimicked the phosphorylation of this site, treatment with EGF had no stimulating effect on tyrosine phosphorylation/activation of the mutant HER2. The results suggested that PKG II inhibits EGF‑induced activation of HER2 through binding with and causing threonine 686 phosphorylation of this oncogenic protein.

Targeted Therapy in Biliary Tract Cancers

OPINION STATEMENT

A paradigm shift towards molecular-based, personalized cancer therapeutics has occurred in recent years and a number of targeted drugs have emerged. Various targeted therapies like erlotinib, trastuzumab, and cetuximab have been approved in lung, breast, and colon cancers, respectively. Numerous clinical trials involving targeted drugs in biliary tract cancers are currently in progress, though none have been approved for this disease. Biliary tract cancers are divided into separate entities both anatomically and in terms of pathogenesis but are grouped together in most trials given their rarity. Combination chemotherapy involving cisplatin and gemcitabine is the current standard of care in the metastatic setting. In this review, we will discuss the various molecular pathways implicated in biliary tract cancers and potential therapeutic targets.

Evaluation of P53, E-cadherin, Cox-2, and EGFR protein immunoexpression on prognostic of resected gallbladder carcinoma

Background

Gallbladder carcinoma presents a dismal prognosis. Choice treatment is surgical resection that is associated a high levels of both morbidity and mortality. Best knowledgement of prognostic factors may result a better selection of patients either for surgical or multimodal treatment.

Aim

To evaluate tecidual immunoexpression of P53, E-cadherin, Cox-2, and EGFR proteins and to correlate these findings with resected gallbladder adenocarcinoma survival.

Methods

Clinical, laboratorial, surgical, and anatomopathological reports of a series of gallbladder adenocarcinoma patients were collected by individualized questionary. Total sample was 42 patients. Median of age was 72 years (35-87). There were seven men and 35 women. Lesion distribuition in according TNM state was the following: T1 (n=2), T2 (n=5), T3 (n=31), T4 (n=4). Twenty-three patients underwent radical resection (R0), while 19 palliative surgery (R1-R2). A block of tissue microarray with neoplasic tissue of each patient was confected. It was performed evaluation of P53, E-Caderine, COX-2, and EGFR proteins imunoexpression. These findings were correlated with overall survival.

Results

Five-year survival was 28%. The median of global survival was eight months. Only immunoexpression of EGFR protein was considered independent variable at multivariated analysis.

Conclusion

Final prognosis was influenced by over-expression of EGFR protein in tumoral tissue.

HER2 and uPAR cooperativity contribute to metastatic phenotype of HER2-positive breast cancer

Human epidermal growth factor receptor type 2 (HER2)-positive breast carcinoma is highly aggressive and mostly metastatic in nature though curable/manageable in part by molecular targeted therapy. Recent evidence suggests a subtype of cells within HER2-positive breast tumors that concomitantly expresses the urokinase plasminogen activator receptor (uPAR) with inherent stem cell/mesenchymal-like properties promoting tumor cell motility and a metastatic phenotype. This HER-positive/uPAR-positive subtype may be partially responsible for the failure of HER2-targeted treatment strategies. Herein we discuss and substantiate the cumulative preclinical and clinical evidence on HER2-uPAR cooperativity in terms of gene co-amplification and/or mRNA/protein co-overexpression. We then propose a regulatory signaling model that we hypothesize to maintain upregulation and cooperativity between HER2 and uPAR in aggressive breast cancer. An improved understanding of the HER2/uPAR interaction in breast cancer will provide critical biomolecular information that may help better predict disease course and response to therapy.

MicroRNA-146b-5p inhibits the growth of gallbladder carcinoma by targeting epidermal growth factor receptor

Gallbladder cancer (GBC) is the most common and aggressive type of biliary tract cancer. The study of potential treatments for GBC has recently focused on microRNAs, a class of small non-coding RNAs, which post-transcriptionally regulate gene expression during various crucial cell processes. The present study aimed to investigate the role of microRNA-146b (miR-146b) in GBC. Human GBC tissue and adjacent normal gallbladder tissue sections were surgically removed and miR-146b-5p expression and the development and pathological characteristics of GBC were investigated. miR-146b-5p expression was reduced in GBC tissue compared with that in adjacent tissue, and a significant correlation was observed between miR-146b-5p expression levels and carcinoma size and development. miR-146b-5p overexpression in the SGC-996 GBC cell line inhibited cell growth through enhanced apoptosis and G1 phase arrest. Furthermore, it was demonstrated that epidermal growth factor receptor (EGFR) was regulated directly by miR-146b-5p and was essential as a mediator of the biological effects of miR-146b-5p in GBC. Enforced expression of EGFR reversed the ability of miR-146b-5p to inhibit proliferation. In conclusion, the present study indicated that the mechanism of action of miR-146b-5p in GBC involves the regulation of EGFR expression.

GATA2 promotes glioma progression through EGFR/ERK/Elk-1 pathway

Among the gliomas, glioblastoma (GBM) is the highest grade and the most malignant glioma tumor. GATA2 is a hematopoietic factor that has been intensely studied in hematopoietic malignancies. Recently, the functions of GATA2 as an oncogene in other types of human cancer have been reported. However, no role for GATA2 in the development and progression of glioma has been reported to date. In the present study, we found that the expression level of GATA2 is upregulated in GBM and is correlated with GBM outcome. Ectopic expression of GATA2 or RNAi-mediated knockdown of GATA2 significantly enhanced or inhibited proliferation, migration and invasion of glioma cells. Moreover, we found that epidermal growth factor receptor and extracellular signal-regulated kinase, as upstream components of the signaling pathway, upregulate GATA2 expression; moreover, GATA2 promotes Elk-1 expression. Therefore, a genetic approach or pharmacological intervention targeting GATA2 could potentially serve as an effective strategy for treating glioma patients.

Target antigen density governs the efficacy of anti-CD20-CD28-CD3 ζ chimeric antigen receptor-modified effector CD8+ T cells

The effectiveness of chimeric Ag receptor (CAR)-transduced T (CAR-T) cells has been attributed to supraphysiological signaling through CARs. Second- and later-generation CARs simultaneously transmit costimulatory signals with CD3ζ signals upon ligation, but may lead to severe adverse effects owing to the recognition of minimal Ag expression outside the target tumor. Currently, the threshold target Ag density for CAR-T cell lysis and further activation, including cytokine production, has not yet been investigated in detail. Therefore, we determined the threshold target Ag density required to induce CAR-T cell responses using novel anti-CD20 CAR-T cells with a CD28 intracellular domain and a CD20-transduced CEM cell model. The newly developed CD20CAR-T cells demonstrated Ag-specific lysis and cytokine secretion, which was a reasonable level as a second-generation CAR. For lytic activity, the threshold Ag density was determined to be ∼200 molecules per target cell, whereas the Ag density required for cytokine production of CAR-T cells was ∼10-fold higher, at a few thousand per target cell. CD20CAR-T cells responded efficiently to CD20-downregulated lymphoma and leukemia targets, including rituximab- or ofatumumab-refractory primary chronic lymphocytic leukemia cells. Despite the potential influence of the structure, localization, and binding affinity of the CAR/Ag, the threshold determined may be used for target Ag selection. An Ag density below the threshold may not result in adverse effects, whereas that above the threshold may be sufficient for practical effectiveness. CD20CAR-T cells also demonstrated significant lytic activity against CD20-downregulated tumor cells and may exhibit effectiveness for CD20-positive lymphoid malignancies.

MicroRNAs in cancer therapeutic response: Friend and foe

Cancer initiation and development engage extremely complicated pathological processes which involve alterations of a large number of cell signaling cascades and functional networks in temporal and spatial orders. During last decades, microRNAs (miRNAs), a class of non-coding RNAs, have emerged as critical players in cancer pathogenesis and progression by modulating many pathological aspects related to tumor development, growth, metastasis, and drug resistance. The major function of miRNAs is to post-transcriptionally regulate gene expression depending on recognition of complementary sequence residing in target mRNAs. Commonly, a particular miRNA recognition sequence could be found in a number of genes, which allows a single miRNA to regulate multiple functionally connected genes simultaneously and/or chronologically. Furthermore, a single gene can be targeted and regulated by multiple miRNAs. However, previous studies have demonstrated that miRNA functions are highly context-dependent, which leads to distinct pathological outcomes in different types of cancer as well as at different stages by alteration of the same miRNA. Here we summarize recent progress in studies on miRNA function in cancer initiation, metastasis and therapeutic response, focusing on breast cancer. The varying functions of miRNAs and potential application of using miRNAs as biomarkers as well as therapeutic approaches are further discussed in the context of different cancers.

Hepatitis B virus X upregulates HuR protein level to stabilize HER2 expression in hepatocellular carcinoma cells

Hepatitis B virus- (HBV-) associated hepatocellular carcinoma (HCC) is the most common type of liver cancer. However, the underlying mechanism of HCC tumorigenesis is very complicated and HBV-encoded X protein (HBx) has been reported to play the most important role in this process. Activation of downstream signal pathways of epidermal growth factor receptor (EGFR) family is known to mediate HBx-dependent HCC tumor progression. Interestingly, HER2 (also known as ErbB2/Neu/EGFR2) is frequently overexpressed in HBx-expressing HCC patients and is associated with their poor prognosis. However, it remains unclear whether and how HBx regulates HER2 expression. In this study, our data showed that HBx expression increased HER2 protein level via enhancing its mRNA stability. The induction of RNA-binding protein HuR expression by HBx mediated the HER2 mRNA stabilization. Finally, the upregulated HER2 expression promoted the migration ability of HBx-expressing HCC cells. These findings deciphered the molecular mechanism of HBx-mediated HER2 upregulation in HBV-associated HCC.

The role of microRNAs in breast cancer migration, invasion and metastasis

MicroRNAs (miRNAs) are a major class of small, noncoding RNA molecules that regulate gene expression by targeting mRNAs to trigger either translational repression or mRNA degradation. They have recently been more widely investigated due to their potential role as targets for cancer therapy. Many miRNAs have been implicated in several human cancers, including breast cancer. miRNAs are known to regulate cell cycle and development, and thus may serve as useful targets for exploration in anticancer therapeutics. The link between altered miRNA signatures and breast cancer development and metastasis can be observed either through the loss of tumor suppressor miRNAs, such as let-7s, miR-30a/31/34a/125s/200s/203/205/206/342 or the overexpression of oncogenic miRNAs, such as miR-10b/21/135a/155/221/222/224/373/520c in breast cancer cells. Some of these miRNAs have also been validated in tumor specimens of breast cancer patients, underscoring their potential roles in diagnostics, as well as targets for novel therapeutics for breast cancer. In this review article, we will provide an overview and update of our current understanding of the mode of action of several of these well characterized miRNAs in breast cancer models. Therefore, better understanding of the gene networks orchestrated by these miRNAs may help exploit the full potential of miRNAs in regards to cancer diagnosis, treatment, and therapeutics.

MMP-9 increases HER2/neu expression and alters apoptosis levels in human mammary epithelial cells (HMEC)

HER2/neu overexpression leads to poorer prognosis and higher risk of disease reoccurrence in breast cancer patients. The causative factors responsible for increasing HER2/neu expression levels on mammary cells are not known. We investigated whether factors associated with inflammation or metastasis could induce HER2/neu expression on human mammary epithelial cells (HMECs). Human mammary epithelial cells and several human breast cancer cell lines used in our studies were treated with several agents, including estrogen and matrix metalloproteinase-9 (MMP-9), either alone or in various combinations. Relative expression of HER2/neu on the surface of target cells was assessed using fluorochrome-tagged antibodies and a fluorescence cytometer. HER2/neu gene expression was also determined by Western blot analysis and PCR. Apoptosis levels were also determined. MMP-9, administered either alone or in combination with interleukin-7 and estrogen, caused a significant rise in HER2/neu expression on the surface of HMECs. The induction in HER2/neu protein expression was suppressed using a MMP-9 inhibitor. Similar results were obtained for breast cancer cells treated with the estrogen in combination with MMP-9. MMP-9 treatment significantly decreased apoptotic levels in HMECs. Our results indicate that MMP-9 is a regulator of HER2/neu expression on human mammary epithelial cells and suggest that upregulation of HER2/neu by MMP-9 may be relevant to altering the characteristics of normal mammary cells toward a transformed phenotype.

MET activation mediates resistance to lapatinib inhibition of HER2-amplified gastric cancer cells

HER2 amplification is found in more than 15% of gastric cancers and is associated with poor clinical outcome. Lapatinib, a dual HER2 and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, has shown promising in vitro results in treating HER2(+) cancer cells. However, several studies have shown that activation of alternative receptor tyrosine kinases can mediate resistance to HER-targeted therapy. Here, we investigated whether activated MET can confer resistance to lapatinib inhibition of gastric cancer cells. A panel of gastric cancer cell lines was treated with lapatinib, and we observed that cell proliferation was reduced by 70% and that the degree of HER2 amplification corresponds to sensitivity to lapatinib. Immunoblotting analysis indicated that phosphorylation of HER2, EGFR, MET, AKT, and extracellular signal-regulated kinase was inhibited by lapatinib and presumably led to cell-cycle arrest as observed with flow cytometry. Hepatocyte growth factor (HGF) activation of MET receptors rescued cells from lapatinib-induced growth inhibition by restimulating the downstream pathways and restoring normal cell-cycle progression. This rescue effect could be abrogated by inhibiting MET with PHA-665752 (a highly specific MET inhibitor) or downregulating MET expression with short interfering RNA. No synergy in growth inhibition was observed when cells were treated with a combination of lapatinib and PHA-665752. Repeat studies using insulin-like growth factor 1 and fibroblast growth factor 3 could not uniformly rescue the lapatinib-treated gastric cancer cells. In conclusion, HGF/MET-mediated resistance to lapatinib is a novel mechanism of resistance to HER2-targeted agents in gastric cancer cells. Development of inhibitors targeting multiple receptors or common downstream signaling proteins merits further investigation.

Association of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 status with total choline concentration and tumor volume in breast cancer patients: an MRI and in vivo proton MRS study

The association of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) status of breast cancer patients with total choline (tCho) concentration and tumor volume was investigated using in vivo proton magnetic resonance spectroscopy and MRI at 1.5 T. Values for tCho concentration were determined in 120 locally advanced breast cancer patients (stages IIB, IIIA, IIIB, and IIIC), 31 early breast cancer patients (stage IIA), 38 patients with benign lesions, and 37 controls. Significantly higher tCho concentration and lower tumor volume were observed in early breast cancer patients compared to locally advanced breast cancer patients (P<0.05). tCho concentration and tumor volume did not correlate with age and menstruation. tCho cutoff values were obtained for the differentiation of malignant from benign breast tissues (2.54 mmol/kg); malignant versus normal (1.45 mmol/kg) and benign versus normal tissues (0.82 mmol/kg). Estrogen receptor negative patients showed significantly larger tumor volumes, indicating higher angiogenesis with aggressive tumor behavior. Nontriple negative and triple positive patients had a significantly higher tCho concentration compared to triple negative patients (P<0.05), indicating complex molecular mechanism of cell proliferation and the molecular heterogeneity of breast lesions. The results indicate the potential use of integration of breast 1H magnetic resonance spectroscopy in diagnostic workup.

ErbB expression, activation, and inhibition with lapatinib and tyrphostin (AG825) in human vestibular schwannomas

BACKGROUND

Pharmacologic agents targeted against the ErbB family, or the intracellular pathways that mediate their effects, could slow clinical progression of vestibular schwannoma (VS) in patients where other modalities carry a high risk-to-benefit ratio.

OBJECTIVE

Determine the identity of the predominant ErbB dimer partners in VS tumors and assess the effects of targeted inhibition of the ErbB molecules on VS growth and proliferation, as well as apoptosis.

SETTING

Academic tertiary referral center.

METHODS

Coimmunoprecipitation and Western blotting of VS tissue, in vitro BrdU assays of proliferation in the presence of lapatinib and tyrphostin (AG825) using primary VS cultures, and annexin V cell death assays and cell cycle assays using propidium iodide staining were performed on HEI193 cell line derived from an neurofibromatosis type 2-associated VS.

RESULTS

Activated ErbB family receptor heterodimers in VS contain predominantly epidermal growth factor receptor (EGFR) and ErbB2. A robust, dose-dependent inhibition of VS growth and proliferation with the dual EGFR/ErbB2 inhibitor, lapatinib, was demonstrated. Lapatinib also inhibited EGF-induced VS proliferation. The selective ErbB2 inhibitor, AG825, inhibited growth to a lesser extent. HEI193 demonstrated apoptosis after lapatinib treatment.

CONCLUSION

Dual EGFR and ErbB2 inhibition with lapatinib or combination therapy may provide therapeutic benefit in VS treatment, but further studies are necessary.

The impact of multi-targeted cyclin-dependent kinase inhibition in breast cancer cells: clinical implications

INTRODUCTION

The progression of the mammalian cell cycle is driven by the transient activation of complexes consisting of cyclins and cyclin-dependent kinases (CDKs). Loss of control over the cell cycle results in accelerated cell division and malignant transformation and can be caused by the upregulation of cyclins, the aberrant activation of CDKs or the inactivation of cellular CDK inhibitors. For these reasons, cell cycle regulators are regarded as very promising therapeutic targets for the treatment of human malignancies.

AREAS COVERED

This review covers the structures and anti-breast cancer activity of selected pharmacological pan-specific CDK inhibitors. Multi-targeted CDK inhibitors affect CDKs involved in the regulation of both cell cycle progression and transcriptional control. The inhibition of CDK7/CDK9 has a serious impact on the activity of RNA polymerase II; when its carboxy-terminal domain is unphosphorylated, it is unable to recruit the cofactors required for transcriptional elongation, resulting in a global transcriptional block. Multi-targeted inhibition of CDKs represses anti-apoptotic proteins and thus promotes the induction of apoptosis. Moreover, the inhibition of CDK7 in estrogen receptor (ER)-positive breast cancer cells prevents activating phosphorylation of ER-α.

EXPERT OPINION

These diverse modes of action make multi-targeted CDK inhibitors promising drugs for the treatment of breast cancers.

Rhein induces apoptosis in human breast cancer cells

Human breast cancers cells overexpressing HER2/neu are more aggressive tumors with poor prognosis, and resistance to chemotherapy. This study investigates antiproliferation effects of anthraquinone derivatives of rhubarb root on human breast cancer cells. Of 7 anthraquinone derivatives, only rhein showed antiproliferative and apoptotic effects on both HER2-overexpressing MCF-7 (MCF-7/HER2) and control vector MCF-7 (MCF-7/VEC) cells. Rhein induced dose- and time-dependent manners increase in caspase-9-mediated apoptosis correlating with activation of ROS-mediated activation of NF-κB- and p53-signaling pathways in both cell types. Therefore, this study highlighted rhein as processing anti-proliferative activity against HER2 overexpression or HER2-basal expression in breast cancer cells and playing important roles in apoptotic induction of human breast cancer cells.

An imbalance in progenitor cell populations reflects tumour progression in breast cancer primary culture models

Background

Many factors influence breast cancer progression, including the ability of progenitor cells to sustain or increase net tumour cell numbers. Our aim was to define whether alterations in putative progenitor populations could predict clinicopathological factors of prognostic importance for cancer progression.

Methods

Primary cultures were established from human breast tumour and adjacent non-tumour tissue. Putative progenitor cell populations were isolated based on co-expression or concomitant absence of the epithelial and myoepithelial markers EPCAM and CALLA respectively.

Results

Significant reductions in cellular senescence were observed in tumour versus non-tumour cultures, accompanied by a stepwise increase in proliferation:senescence ratios. A novel correlation between tumour aggressiveness and an imbalance of putative progenitor subpopulations was also observed. Specifically, an increased double-negative (DN) to double-positive (DP) ratio distinguished aggressive tumours of high grade, estrogen receptor-negativity or HER2-positivity. The DN:DP ratio was also higher in malignant MDA-MB-231 cells relative to non-tumourogenic MCF-10A cells. Ultrastructural analysis of the DN subpopulation in an invasive tumour culture revealed enrichment in lipofuscin bodies, markers of ageing or senescent cells.

Conclusions

Our results suggest that an imbalance in tumour progenitor subpopulations imbalances the functional relationship between proliferation and senescence, creating a microenvironment favouring tumour progression.

Assessment of free dye in solutions of dual-labeled antibody conjugates for in vivo molecular imaging

PURPOSE

Recent preclinical and clinical studies show that dyes that excite and fluoresce in the near-infrared range may be used for tracking and detecting disease targets in vivo. A method for quantifying free dye molecules in antibody conjugate preparations is required for agent batch release and for translation into the clinic.

PROCEDURES

Herein, we developed and validated a SDS-PAGE method to determine the percentage of free IRDye 800 CW in (DTPA)(n)-trastuzumab-(IRDye 800)(m) conjugate sample preparations in which high-performance liquid chromatography (HPLC) assessment of free dye was not possible.

RESULTS

The SDS-PAGE assay was accurate and valid for free IRDye 800 CW amounts between 38 and 4 mol% of total dye. Gel sample preparation reagent affected the specificity of the assay, and lower and upper limits of quantitation and detection were determined.

CONCLUSION

This method may be applicable to other near-infrared dye-conjugated antibody-based imaging agents in which HPLC assessment of purity is not feasible. This validated method for quality assurance will facilitate the translation of dual-labeled antibody conjugates for nuclear and optical imaging.

Clinicopathological significance of calreticulin in breast invasive ductal carcinoma

Calreticulin is a chaperone protein located in the lumen of the endoplasmic reticulum. The association of calreticulin with pathological conditions such as autoimmune disorders and certain types of cancer have been reported. However, little is known about its role in the pathogenesis of breast cancer. The aim of this study was to determine the expression of calreticulin in vitro and correlate its expression levels in breast cancer tissue samples with clinicopathological parameters. Calreticulin expression was evaluated in MCF-7 and MDA-MB-231 breast cancer cells by real-time RT-PCR, Western blot, immunohistochemistry, and immunofluorescence staining. Patient tissue microarrays were constructed from 228 breast cancer specimens for immunohistochemical analysis. The in vitro study showed a higher calreticulin expression in more aggressive MDA-MB-231 cells as compared with MCF-7 cells at both mRNA and protein levels. In all, 227 out of 228 breast cancer samples exhibited calreticulin staining in at least 5% of the cancer cells. Calreticulin immunostaining was observed to be localized to the cytoplasm of the cancer cells. Regression analysis of calreticulin immunostaining in the tissue microarrays revealed that its expression was positively correlated to logarithm of (log) tumor size (P=0.046) and development of distant metastasis (P=0.017). Multivariate analysis confirmed calreticulin expression as an independent predictor of log tumor size and occurrence of distant metastasis. The data suggest that calreticulin expression is associated with more advanced tumors and is a potential prognostic biomarker.

Musashi1 regulates breast tumor cell proliferation and is a prognostic indicator of poor survival

Background

Musashi1 (Msi1) is a conserved RNA-binding protein that regulates the Notch and Wnt pathways, and serves as a stem cell marker in the breast and other tissues. It is unknown how Msi1 relates to other breast cancer markers, whether it denotes tumor initiating cells (TICs), and how it affects gene expression and tumor cell survival in breast cancer cells.

Results

Msi1 expression was analyzed in 20 breast cancer cell lines and in 140 primary breast tumors by western blotting and immunohistochemistry, respectively. Lentivirus RNA interference was used to reduce Msi1 expression in breast cancer cell lines MCF-7 and T47D grown as spheroid cultures and to assess stem cell gene expression and the growth of these cell lines as xenografts. In normal human breast tissue, Msi1 was expressed in 10.6% of myoepithelum and 1.2% of ductal epithelium in the terminal ductal lobular unit (TDLU), whereas, less than 0.05% of ductal epithelium and myoepithelium in large ducts outside the TDLU expressed Msi1. Msi1 was expressed in 55% of the breast cancer cell lines and correlated with ErbB2 expression in 50% of the cell lines. Msi1 was expressed in 68% of primary tumors and in 100% of lymph node metastases, and correlated with 5 year survival. Msi1 was enriched in CD133⁺ MCF-7 and T47D cells and in spheroid cultures of these cells, and Msi1 'knockdown' (KD) with a lentivirus-expressed shRNA decreased the number and size of spheroid colonies. Msi1 KD reduced Notch1, c-Myc, ErbB2 and pERK1/2 expression, and increased p21^CIP1 expression, which is consistent with known Msi1 target mRNAs. Msi1 KD also reduced the expression of the somatic and embryonic stem cell markers, CD133, Bmi1, Sox2, Nanog and Oct4. Xenografts of MCF-7 and T47D Msi1 KD cells resulted in a marked reduction of tumor growth, reduced Msi1 and Notch1 expression and increased p21^CIP1 expression.

Conclusion

Msi1 is a negative prognostic indicator of breast cancer patient survival, and is indicative of tumor cells with stem cell-like characteristics. Msi1 KD reduces tumor cell survival and tumor xenograft growth, suggesting that it may represent a novel target for drug discovery.

Targeting endothelin A receptor enhances anti-proliferative and anti-invasive effects of the HER2 antibody trastuzumab in HER2-overexpressing breast cancer cells

Human epidermal growth factor receptor 2 (HER2) is frequently overexpressed in human breast cancers. It is known to drive tumor growth and progression and represents a prominent target in breast cancer therapy. The endothelin (ET) system, in particular ET-1 and its receptor ET(A)R, is of major relevance for breast cancer growth and invasion. Having previously demonstrated coexpression of ET(A)R and HER2 in breast tumors, this study was designed to investigate molecular interactions of HER2 (including the epidermal growth factor receptor EGFR as its major coreceptor) and ET signaling, and the potential benefit of a combined anti-HER2/ET(A)R treatment in human breast cancer cells. Dual HER2-ET(A)R targeting utilizing trastuzumab (monoclonal anti-HER2 antibody) and the ET(A)R antagonist atrasentan was superior to each agent alone in inhibiting basal and EGF-induced proliferation and invasion of HER2-overexpressing BT-474 and SK-BR-3 cells. EGF-induced invasion was partially inhibited by atrasentan alone, suggesting the involvement of ET(A)R in EGF receptor mediated invasion of breast cancer cells. Moreover, secretion of the pro-invasive ET-1 was shown to be induced by EGF via EGFR and HER2, including MAPK-dependent signaling. In turn, an ET-1/ET(A)R-dependent regulation of EGFR protein expression and phosphorylation (at Tyr845) was observed, which may contribute to the additional anti-proliferative and anti-invasive effects of atrasentan on trastuzumab treated cells; reconfirming, atrasentan failed to enhance inhibitory effects of EGFR-targeted agents. This study suggests complex interactions between HER2/EGFR and ET pathways in breast cancer and supports the hypothesis that dual HER2-ET(A)R targeting may represent a highly effective approach in breast cancer treatment.