Anti-human HB-EGF monoclonal antibodies inhibiting ectodomain shedding of HB-EGF and diphtheria toxin binding

The Multiple Functions of HB-EGF in Female Reproduction and Related Cancer: Molecular Mechanisms and Targeting Strategies

Heparin-binding growth factor (HB-EGF) is a member of the epidermal growth factor (EGF) ligand family which has a crucial role in women's health. However, there is a lack of comprehensive review to summarize the significance of HB-EGF. Therefore, this work first described the expression patterns of HB-EGF in the endometrium and ovary of different species and gestational time. Then, the focus was on exploring how it promotes the successful implantation and regulates the process of decidualization and the function of ovarian granulosa cells as an intermediate molecule. Otherwise, we also focused on the clinical and prognostic significance of HB-EGF in female-related cancers (including ovarian cancer, cervical cancer, and endometrial cancer) and breast cancer. Lastly, the article also summarizes the current drugs targeting HB-EGF in the treatment of ovarian cancer and breast cancer. Overall, these studies found that the expression of HB-EGF in the endometrium is spatiotemporal and species-specific. And it mediates the dialogue between the blastocyst and endometrium, promoting synchronous development of the blastocyst and endometrium as an intermediate molecule. HB-EGF may serve as a potentially valuable prognostic clinical indicator in tumors. And the specific inhibitor of HB-EGF (CRM197) has a certain anti-tumor ability, which can exert synergistic anti-tumor effects with conventional chemotherapy drugs. However, it also suggests that more research is needed in the future to elucidate its specific mechanisms and to accommodate clinical studies with a larger sample size to clarify its clinical value.

Systemic Administration of siRNA with Anti-HB-EGF Antibody-Modified Lipid Nanoparticles for the Treatment of Triple-Negative Breast Cancer

Triple-negative breast cancer is one of the intractable cancers that are not sensitive to treatment with existing molecular-targeted drugs. Recently, there has been much interest in RNA interference-mediated treatment of triple-negative breast cancer. In the present study, we have developed lipid nanoparticles encapsulating siRNA (LNP-siRNA) decorated with an Fab' antibody against heparin-binding EGF-like growth factor (αHB-EGF LNP-siRNA). αHB-EGF LNP-siRNA targeting polo-like kinase 1 (PLK1) was prepared and evaluated for its anticancer effect using MDA-MB-231 human triple-negative breast cancer cells overexpressing HB-EGF on their cell surface. Biodistribution data of radioisotope-labeled LNP and fluorescence-labeled siRNA indicated that αHB-EGF LNP effectively delivered siRNA to tumor tissue in MDA-MB-231 carcinoma-bearing mice. Expression of PLK1 protein in the tumors was clearly suppressed after intravenous injection of αHB-EGF LNP-siPLK1. In addition, tumor growth was significantly inhibited by treatment with this formulation of siRNA and an antibody-modified carrier. These findings indicate that αHB-EGF LNP is a promising carrier for the treatment of HB-EGF-expressing cancers, including triple-negative breast cancer.

BK-UM in patients with recurrent ovarian cancer or peritoneal cancer: a first-in-human phase-I study

Background

BK-UM (CRM197) is a mutant form of diphtheria toxin and a specific inhibitor of heparin-binding epidermal growth factor-like growth factor (HB-EGF). We assessed the safety, pharmacokinetics, recommended dose, and efficacy of BK-UM in patients with recurrent ovarian cancer (OC) or peritoneal cancer (PC), and measured HB-EGF levels in serum and abdominal fluid after BK-UM administration.

Methods

Eleven patients with advanced or recurrent OC or PC were enrolled and treated with BK-UM via the intraperitoneal route. The dose was escalated (1.0, 2.0, 3.3, and 5.0 mg/m²) using a 3 + 3 design.

Results

Eight of 11 patients completed treatment. No dose-limiting toxicity (DLT) was experienced at dose levels 1 (1.0 mg/m²) and 2 (2.0 mg/m²). Grade 3 transient hypotension as an adverse event (defined as a DLT in the present study) was observed in two of four patients at dose level 3 (3.3 mg/m²). Treatment with BK-UM was associated with decreases in HB-EGF levels in serum and abdominal fluid in seven of 11 patients and five of eight patients, respectively. Clinical outcomes included a partial response in one patient, stable disease in five patients, and progressive disease in five patients.

Conclusions

BK-UM was well tolerated at doses of 1.0 and 2.0 mg/m², with evidence for clinical efficacy in patients with recurrent OC or PC. A dose of 2.0 mg/m² BK-UM is recommended for subsequent clinical trials.

Trial registration

This trial was prospectively performed as an investigator-initiated clinical trial. The trial numbers are UMIN000001002 and UMIN000001001, with registration dates of 1/30/2008 and 2/4/2008, respectively. UMIN000001001 was registered as a trial for the continuous administration of BK-UM after UMIN000001002.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3071-5) contains supplementary material, which is available to authorized users.

Heparin-binding epidermal growth factor-like growth factor and hepatocyte growth factor inhibit cholestatic liver injury in mice through different mechanisms

In contrast to hepatocyte growth factor (HGF), the therapeutic potential and pathophysiologic roles of heparin-binding epidermal growth factor-like growth factor (HB-EGF) in liver diseases remain relatively unknown. To address the lack of effective pharmacologic treatments for cholestatic liver injuries, as well as to clarify the biologic features of these growth factors, we explored the effects of HB-EGF and HGF in mice with cholestatic liver injury induced by bile duct ligation (BDL). The mice were assessed 3, 5 and/or 14 days after BDL (acute, subacute and/or chronic phases, respectively) and intravenous injection of adenoviral vector expressing LacZ (control), HB-EGF, HGF, or HB-EGF and HGF. HB-EGF, HGF, or a combination of the growth factors exerted potent antioncotic (antinecrotic), antiapoptotic, anticholestatic, and regenerative effects on hepatocytes in vivo, whereas no robust antiapoptotic or regenerative effects were detected in interlobular bile ducts. Based on serum transaminase levels, the acute protective effects of HB-EGF on hepatocytes were greater than those of HGF. On the other hand, liver fibrosis and cholestasis during the chronic phase were more potently inhibited by HGF compared with HB-EGF. Compared with either growth factor alone, combining HB-EGF and HGF produced greater anticholestatic and regenerative effects during the chronic phase. Taken together, these findings suggest that HB-EGF and HGF inhibited BDL-induced cholestatic liver injury, predominantly by exerting acute cytoprotective and chronic antifibrotic effects, respectively; combining the growth factors enhanced the anticholestatic effects and liver regeneration during the chronic phase. Our results contribute to a better understanding of the pathophysiologic roles of HB-EGF and HGF, as well as to the development of novel effective therapies for cholestatic liver injuries.

Characterization of a Novel Anti-Human HB-EGF Monoclonal Antibody Applicable for Paraffin-Embedded Tissues and Diagnosis of HB-EGF-Related Cancers

Heparin-binding EGF-like growth factor (HB-EGF) is a member of the EGF family of growth factors that bind to and activate the EGF receptor (EGFR/ErbB1) and ErbB4. HB-EGF plays pivotal roles in pathophysiological processes, including cancer. Thus, monoclonal antibodies (mAbs) for HB-EGF detection could be an important tool in the therapeutic diagnosis of HB-EGF-related cancers and other diseases. However, few mAbs, especially those applicable for immunohistochemistry (IHC), have been established to date. In this study, we generated a clone of hybridoma-derived mAb 2-108 by immunizing mice with recombinant human HB-EGF protein expressed by human cells. The mAb 2-108 specifically bound to human HB-EGF but not to mouse HB-EGF and was successful in immunoblotting, even under reducing conditions, immunoprecipitation, and immunofluorescence for unfixed as well as paraformaldehyde-fixed cells. Notably, this mAb was effective in IHC of paraffin-embedded tumor specimens. Epitope mapping analysis showed that mAb 2-108 recognized the N-terminal prodomain in HB-EGF. These results indicate that this new anti-HB-EGF mAb 2-108 would be useful in the diagnosis of HB-EGF-related cancers and would be a strong tool in both basic and clinical research on HB-EGF.

Identification of diphtheria toxin R domain mutants with enhanced inhibitory activity against HB-EGF

Heparin-binding epidermal growth factor-like growth factor (HB-EGF), a ligand of EGF receptor, is involved in the growth and malignant progression of cancers. Cross-reacting material 197, CRM197, a non-toxic mutant of diphtheria toxin (DT), specifically binds to the EGF-like domain of HB-EGF and inhibits its mitogenic activity, thus CRM197 is currently under evaluation in clinical trials for cancer therapy. To develop more potent DT mutants than CRM197, we screened various mutant proteins of R domain of DT, the binding site for HB-EGF. A variety of R-domain mutant proteins fused with maltose-binding protein were produced and their inhibitory activity was evaluated in vitro. We found four R domain mutants that showed much higher inhibitory activity against HB-EGF than wild-type (WT) R domain. These R domain mutants suppressed HB-EGF-dependent cell proliferation more effectively than WT R domain. Surface plasmon resonance revealed their higher affinity to HB-EGF than WT R domain. CRM197(R460H) carrying the newly identified mutation showed increased cell proliferation inhibitory activity and affinity to HB-EGF. These results suggest that CRM197(R460H) or other recombinant proteins carrying newly identified mutation(s) in the R domain are potential therapeutics targeting HB-EGF.

Role of epidermal growth factor receptor signaling in the interaction of Neisseria meningitidis with endothelial cells

Neisseria meningitidis, the causative agent of meningitis and septicemia, attaches to and invades various cell types. Both steps induce and/or require tyrosine phosphorylation of host cell proteins. Here, we used a phospho array platform to identify active receptor tyrosine kinases (RTKs) and key signaling nodes in N. meningitidis-infected brain endothelial cells to decipher RTK-dependent signaling pathways necessary for bacterial uptake. We detected several activated RTKs, including the ErbB family receptors epidermal growth factor receptor (EGFR), ErbB2, and ErbB4. We found that pharmacological inhibition and genetic ablation of ErbB receptor tyrosine phosphorylation and expression resulted in decreased bacterial uptake and heterologous expression of EGFR, ErbB2, or ErbB4 in Chinese ovary hamster (CHO-K1) cells, which do not express of EGFR and ErbB4; the decrease caused a significant increase in meningococcal invasion. Activation of EGFR and ErbB4 was mediated by transactivation via the common ligand HB-EGF (heparin-binding EGF-like ligand), which was significantly elevated in infected cell culture supernatants. We furthermore determined that N. meningitidis induced phosphorylation of EGFR at Tyr845 independent of ligand binding, which required c-Src activation and was involved in mediating uptake of N. meningitidis into eukaryotic cells. Increased uptake was repressed by expression of EGFR Y845F, which harbored a point mutation in the kinase domain. In addition, activation of ErbB4 at its autophosphorylation site, Tyr1284, and phosphorylation of ErbB2 Thr686 were observed. Altogether, our results provide evidence that EGFR, ErbB2, and ErbB4 are activated in response to N. meningitidis infection and shed new light on the role of ErbB signaling in meningococcal infection biology.

Molecular hierarchy of heparin-binding EGF-like growth factor-regulated angiogenesis in triple-negative breast cancer

Heparin-binding EGF-like growth factor (HB-EGF) is one of several proangiogenic factors and represents a possible therapeutic target for patients with triple-negative breast cancer (TNBC). However, the role of HB-EGF in promoting tumor aggressiveness in TNBC remains unclear. To investigate specific genes and pathways involved in TNBC tumorigenesis, we profiled gene expression changes in two TNBC cell lines under two-dimensional culture (2DC) and three-dimensional culture (3DC) and in a tumor xenograft model. We identified simultaneous upregulation of HB-EGF, VEGFA, and angiopoietin-like 4 (ANGPTL4) in 3DC and tumor xenografts, compared with 2DC. We show that HB-EGF regulates the expression of VEGFA or ANGPTL4 via transcriptional regulation of hypoxia-inducible factor-1α and NF-κB. Furthermore, suppression of VEGFA or ANGPTL4 expression enhanced HB-EGF expression, highlighting a unique regulatory loop underlying this angiogenesis network. Targeted knockdown of HB-EGF significantly suppressed tumor formation in a TNBC xenograft model, compared with individual knockdown of either VEGFA or ANGPTL4, by reducing the expression of both VEGFA and ANGPTL4. In patients with TNBC, VEGFA or ANGPTL4 expression was also significantly correlated with HB-EGF expression. Low concentrations of exogenously added HB-EGF strongly activated the proliferation of endothelial cells, tube formation, and vascular permeability in blood vessels, in a similar fashion to high doses of VEGFA and ANGPTL4. Taken together, these results suggest that HB-EGF plays a pivotal role in the acquisition of tumor aggressiveness in TNBC by orchestrating a molecular hierarchy regulating tumor angiogenesis.

A potent anti-HB-EGF monoclonal antibody inhibits cancer cell proliferation and multiple angiogenic activities of HB-EGF

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the epidermal growth factor family and has a variety of physiological and pathological functions. Modulation of HB-EGF activity might have a therapeutic potential in the oncology area. We explored the therapeutic possibilities by characterizing the in vitro biological activity of anti-HB-EGF monoclonal antibody Y-142. EGF receptor (EGFR) ligand and species specificities of Y-142 were tested. Neutralizing activities of Y-142 against HB-EGF were evaluated in EGFR and ERBB4 signaling. Biological activities of Y-142 were assessed in cancer cell proliferation and angiogenesis assays and compared with the anti-EGFR antibody cetuximab, the HB-EGF inhibitor CRM197, and the anti-vascular endothelial growth factor (VEGF) antibody bevacizumab. The binding epitope was determined with alanine scanning. Y-142 recognized HB-EGF as well as the EGFR ligand amphiregulin, and bound specifically to human HB-EGF, but not to rodent HB-EGF. In addition, Y-142 neutralized HB-EGF-induced phosphorylation of EGFR and ERBB4, and blocked their downstream ERK1/2 and AKT signaling. We also found that Y-142 inhibited HB-EGF-induced cancer cell proliferation, endothelial cell proliferation, tube formation, and VEGF production more effectively than cetuximab and CRM197 and that Y-142 was superior to bevacizumab in the inhibition of HB-EGF-induced tube formation. Six amino acids in the EGF-like domain were identified as the Y-142 binding epitope. Among the six amino acids, the combination of F115 and Y123 determined the amphiregulin cross-reactivity and that F115 accounted for the species selectivity. Furthermore, it was suggested that the potent neutralizing activity of Y-142 was derived from its recognition of R142 and Y123 and its high affinity to HB-EGF. Y-142 has a potent HB-EGF neutralizing activity that modulates multiple biological activities of HB-EGF including cancer cell proliferation and angiogenic activities. Y-142 may have a potential to be developed into a therapeutic agent for the treatment of HB-EGF-dependent cancers.

Characterization of a variety of neutralizing anti-heparin-binding epidermal growth factor-like growth factor monoclonal antibodies by different immunization methods

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the epidermal growth factor family. The accumulated evidence on the tumor-progressing roles of HB-EGF has suggested that HB-EGF-targeted cancer therapy is expected to be promising. However, the generation of neutralizing anti-HB-EGF monoclonal antibodies (mAbs) has proved difficult. To overcome this difficulty, we performed a hybridoma approach using mice from different genetic backgrounds, as well as different types of HB-EGF immunogens. To increase the number of hybridoma clones to screen, we used an electrofusion system to generate hybridomas and a fluorometric microvolume assay technology to screen anti-HB-EGF mAbs. We succeeded in obtaining neutralizing anti-HB-EGF mAbs, primarily from BALB/c and CD1 mice, and these were classified into 7 epitope bins based on their competitive binding to the soluble form of HB-EGF (sHB-EGF). The mAbs showed several epitope bin-dependent characteristics, including neutralizing and binding activity to human sHB-EGF, cross-reactivity to mouse/rat sHB-EGF and binding activity to the precursor form of HB-EGF. The neutralizing activity was also validated in colony formation assays. Interestingly, we found that the populations of mAb bins and the production rates of the neutralizing mAbs were strikingly different by mouse strain and by immunogen type. We succeeded in generating a variety of neutralizing anti-HB-EGF mAbs, including potent sHB-EGF neutralizers that may have potential as therapeutic agents for treating HB-EGF-dependent cancers. Our results also suggest that immunization approaches using different mouse strains and immunogen types affect the biological activity of individual neutralizing antibodies.

Heparin-binding EGF-like growth factor promotes epithelial-mesenchymal transition in human keratinocytes

We have shown that autocrine proliferation of human keratinocytes (KC) is strongly dependent upon amphiregulin (AREG), whereas blockade of heparin-binding EGF-like growth factor (HB-EGF) inhibits KC migration in scratch wound assays. Here we demonstrate that expression of soluble HB-EGF (sHB-EGF) or full-length transmembrane HB-EGF (proHB-EGF), but not proAREG, results in profound increases in KC migration and invasiveness in monolayer culture. Coincident with these changes, HB-EGF significantly decreases mRNA expression of several epithelial markers including keratins 1, 5, 10, and 14, while increasing expression of markers of cellular motility including SNAI1, ZEB1, COX-2 and MMP1. Immunostaining revealed HB-EGF-induced expression of the mesenchymal protein vimentin and decreased expression of E-cadherin as well as nuclear translocation of β-catenin. Suggestive of a trade-off between KC motility and proliferation, overexpression of HB-EGF also reduced KC growth by more than 90%. We also show that HB-EGF is strongly induced in regenerating epidermis after partial thickness wounding of human skin. Taken together, our data suggest that expression of HB-EGF in human KC triggers a migratory and invasive phenotype with many features of epithelial-mesenchymal transition (EMT), which may be beneficial in the context of cutaneous wound healing.

Species specificity of ADAM10 and ADAM17 proteins in interleukin-6 (IL-6) trans-signaling and novel role of ADAM10 in inducible IL-6 receptor shedding

Hypomorphic ADAM17(ex/ex) mice showed defects in mucosal regeneration due to inefficient enhanced GFR shedding. ADAM17 is the main sheddase of interleukin-6 receptor (IL-6R) to induce IL-6 trans-signaling. However, serum levels of soluble murine IL-6R were not reduced in ADAM17(ex/ex) mice, and murine ADAM17 was not the major sheddase of murine IL-6R. Shedding of murine IL-6R by murine ADAM17 was rescued in chimeric murine IL-6R proteins containing any extracellular domain but not the transmembrane and intracellular domain of human IL-6R. Apoptosis is a physiological stimulus of ADAM17-mediated shedding of human IL-6R. Even though apoptosis induced IL-6R shedding in mice, the responsible protease was identified as ADAM10. ADAM10 also was identified as protease responsible for ionomycin-induced shedding of murine and human IL-6R. However, in ADAM10-deficient murine embryonic fibroblasts, compensatory shedding of human IL-6R was mediated by ADAM17, but loss of ADAM10-mediated shedding of murine IL-6R was compensated by an as-yet-unidentified protease. Finally, we identified physiological purinergic P2X7 receptor stimulation as a novel inducer of murine and human IL-6R shedding solely mediated by ADAM10. In conclusion, we describe an unexpected species specificity of ADAM10 and ADAM17 and identified ADAM10 as novel inducible sheddase of IL-6R in mice and humans, which might have consequences for the interpretation of phenotypes from ADAM17- and ADAM10-deficient mice.