Receptor Tyrosine Kinases as Candidate Prognostic Biomarkers and Therapeutic Targets in Meningioma.

Meningioma (MGM) is the most common type of intracranial tumor in adults. The validation of novel prognostic biomarkers to better inform tumor stratification and clinical prognosis is urgently needed. Many molecular and cellular alterations have been described in MGM tumors over the past few years, providing a rational basis for the identification of biomarkers and therapeutic targets. The role of receptor tyrosine kinases (RTKs) as oncogenes, including those of the ErbB family of receptors, has been well established in several cancer types. Here, we review histological, molecular, and clinical evidence suggesting that RTKs, including the epidermal growth factor receptor (EGFR, ErbB1), as well as other members of the ErbB family, may be useful as biomarkers and therapeutic targets in MGM.

Quantitative assessment of HER2 gene amplification of breast cancer using droplet digital PCR.

We previously reported the usefulness of droplet digital polymerase chain reaction (ddPCR) for the assessment of Human epithelial growth factor receptor 2 (HER2) gene amplification in breast cancer using formalin-fixed and paraffin-embedded sections. In our previous study, we combined HER2/CEP17 ratio (HER2 gene signals to chromosome 17 signals) with ddPCR and tumor content ratio (TCR) of each sample and determined the HER2 status by adopting a two-dimensional chart. This "ddPCR-TCR method" showed a high concordance with conventional HER2 status. In this study, we updated our method to assess the HER2 status of breast cancer in a more quantitative manner. We combined obtained data of the ddPCR ratio [Rx ] and TCR [x]; we calculated "(Rx - 1)/x + 1" for 41 samples with primary breast cancer and named the value led by this formula as "eHER2 (estimated HER2/CEP17 ratio of a tumor cell)". eHER2 was equivalent to conventional in situ hybridization (ISH) HER2/CEP17 ratio in most cases. eHER2 and ISH ratio showed a strong correlation (Spearman rank correlation ρ = 0.70, p < 0.0001). The obtained results indicated that eHER2 is a potential tool for HER2 status diagnosis in breast cancer.

Genomic and transcriptomic analysis of pituitary adenomas reveals the impacts of copy number variations on gene expression and clinical prognosis among prolactin-secreting subtype.

Pituitary adenomas (PAs) are slow growing and benign primary intracranial tumors that often cause occupying effects or endocrine symptoms. PAs can be classified into various subtypes according to hormone secretion. Although widespread transcriptional alterations that cause aberrant hormone secretion have been characterized, the impact of genomic variations on transcriptional alterations is unclear due to the rare occurrence of single-nucleotide variations in PA. In this study, we performed whole-genome sequencing (WGS) on 76 PA samples across three clinical subtypes (PRL-PAs; GH-PAs, and NFPAs); transcriptome sequencing (RNA-seq) of 54 samples across these subtypes was also conducted. Nine normal pituitary tissues were used as controls. Common and subtype-specific transcriptional alterations in PAs were identified. Strikingly, widespread genomic copy number amplifications were discovered for PRL-PAs, which are causally involved in transcriptomic changes in this subtype. Moreover, we found that the high copy number variations (CNVs) in PRL-PA cause increased prolactin production, drug resistance and proliferative capacity, potentially through key genes with copy number amplification and transcriptional activation, such as BCAT1. This study provides insight into how genomic CNVs affect the transcriptome and clinical outcomes of PRL-PA and sheds light on the development of potential therapeutics for aberrantly activated targets.

Clozapine-dependent inhibition of EGF/neuregulin receptor (ErbB) kinases.

Clozapine is an antipsychotic agent prescribed to psychotic patients exhibiting tolerance and/or resistance to the conventional antipsychotic medications that mainly drive monoamine antagonism. As the pharmacological fundamentals of its unique antipsychotic profile have been unrevealed, here, we attempted to obtain hints at this question. Here, we found that clozapine directly acts on ErbB kinases to downregulate epidermal growth factor (EGF)/neuregulin signaling. In cultured cell lines and cortical neurons, EGF-triggered ErbB1 phosphorylation was diminished by 30 µM clozapine, but not haloperidol, risperidone, or olanzapine. The neuregulin-1-triggered ErbB4 phosphorylation was attenuated by 10 µM clozapine and 30 µM haloperidol. We assumed that clozapine may directly interact with the ErbB tyrosine kinases and affect their enzyme activity. To test this assumption, we performed in vitro kinase assays using recombinant truncated ErbB kinases. Clozapine (3-30 µM) significantly decreased the enzyme activity of the truncated ErbB1, B2, and B4 kinases. Acute in vivo administration of clozapine (20 mg/kg) to adult rats significantly suppressed the basal phosphorylation levels of ErbB4 in the brain, although we failed to detect effects on basal ErbB1 phosphorylation. Altogether with the previous findings that quinazoline inhibitors for ErbB kinases harbor antipsychotic potential in animal models for schizophrenia, our present observations suggest the possibility that the micromolar concentrations of clozapine can attenuate the activity of ErbB receptor kinases, which might illustrate a part of its unique antipsychotic psychopharmacology.

Neuregulin-1-ErbB signaling promotes microglia activation contributing to mechanical allodynia of cyclophosphamide-induced cystitis.

AIMS: Central sensitization playsimportant roles in cyclophosphamide (CYP)-induced cystitis. In addition, as a visceral pain, CYP-induced chronic pain shares common pathophysiological mechanisms with neuropathic pain. Previous studies demonstrated that neuregulin-1 (Nrg1)-ErbB signaling contributes to neuropathic pain, but whether and how this signaling influences mechanical allodynia in CYP-induced cystitis is unclear. This study aimed to determine whether and how Nrg1-ErbB signaling modulates mechanical allodynia in a CYP-induced cystitis rat model. METHODS: Systemic injection with CYP was used to establish a rat model of bladder pain syndrome/interstitial cystitis (BPS/IC). An irreversible ErbB family receptor inhibitor, PD168393, and exogenous Nrg1 were intrathecally injected to modulate Nrg1-ErbB signaling. Mechanical allodynia in the lower abdomen was assessed with von-Frey filaments using the up-down method. Western blot analysis and immunofluorescence staining were used to measure the expression of Nrg1-ErbB signaling, Iba-1, p-p38, and IL-1ß in the L6-S1 spinal dorsal horn (SDH). RESULTS: We observed upregulation of Nrg1-ErbB signaling as well as overexpression of the microglia activation markers Iba-1 and p-p38 and the proinflammatory factor, interleukin-1ß (IL-1ß), in the SDH of the cystitis group. Further, treatment with PD168393 attenuated mechanical allodynia in CYP-induced cystitis and inhibited microglia activation, leading to decreased production of IL-1ß. The inhibitor PD168393 reversed the algesic effect of exogenous Nrg1 on the cystitis model. CONCLUSIONS: Nrg1-ErbB signaling may promote microglia activation, contributing to mechanical allodynia of CYP-induced cystitis. Our study showed that modulation of Nrg1-ErbB signaling may have therapeutic value for treating pain symptoms in BPS/IC.

A fungicide miconazole ameliorates tri-o-cresyl phosphate-induced demyelination through inhibition of ErbB/Akt pathway.

Organophosphorus compound (OP)-induced delayed neuropathy (OPIDN) is characterized by distal axonal degeneration and demyelination of the central and peripheral axons, which leads to progressive muscle weakness, ataxia and paralysis in several days after OP intoxication. This study aimed to investigate the possible use of an imidazole fungicide miconazole as a novel therapy for OPIDN. Adult hens, the most commonly used animal models in OPIDN studies, were orally given tri-o-cresyl phosphate (TOCP). We showed that miconazole, which was administered daily to hens beginning on the 7th day after TOCP exposure, drastically ameliorated the neurotoxic symptoms and histopathological damages in spinal cord and sciatic nerves. Mechanistically, miconazole inhibited the TOCP-induced activation of ErbB/Akt signaling, and enhanced the myelin basic protein (MBP) expression. In a glial cell model sNF96.2 cells, miconazole restored the TOCP-inhibited MBP expression, and promoted cell differentiation as well as cell migration by inhibiting the activation of ErbB/Akt signaling pathway. In sum, miconazole, a synthetic imidazole fungicide, could ameliorate the symptoms and histopathological changes of OPIDN, probably by promoting glial cell differentiation and migration to enhance myelination via inhibiting the activation of ErbB/Akt. Thus, miconazole is a promising candidate therapy for the clinical treatment of OPIDN.

Astraglaus polysaccharide protects diabetic cardiomyopathy by activating NRG1/ErbB pathway.

Diabetic cardiomyopathy (DCM) is one of the main cardiac complications among diabetic patients. According to previous studies, the pathogenesis of DCM is associated with oxidative stress, apoptosis and proliferation of local cardiac cells. It showed, NRG1 can improve the function of mitochondria, and thereby, increasing proliferation and decreasing apoptosis of cardiac muscle cell via ErbB/AKT signaling, also, exert antioxidative function. Besides, NRG1/ErbB pathway was impaired in the DCM model which suggested this signaling played key role in DCM. Astraglaus polysaccharide (APS), one of the active components of Astragalus mongholicus, showed striking antioxidative effect. Here, in this study, our data showed that APS can promote proliferation and decrease apoptosis in AGE-induced DCM cell model, besides, APS can decrease intracellular ROS level, increase activity of SOD, GSH-Px and lower level of MDA and NO in DCM cell model, indicating APS exerted antioxidative function in DCM model cells. Besides, western blot results revealed APS induced NRG1 expressing and the phosphorylation level of ErbB2/4. In addition, the elevated NRG1 promoted AKT and PI3k phosphorylation which indicated APS may exert its function by NRG1/ErbB and the downstream AKT/PI3K signaling. Canertinib is ErbB inhibitor. The effect of APS on proliferation, apoptosis, antioxidation and NRG1/ErbB pathway was partly abolished after the cells were co-treated with APS and canertinib. Taken together, these results suggested APS may display its protective function in DCM cells by activating NGR1/ErbB signaling pathway. And our study increased potential for prevention and therapy to DCM.

Differential recruitment of CD44 isoforms by ErbB ligands reveals an involvement of CD44 in breast cancer.

Members of the CD44 family of transmembrane glycoproteins control cell signaling pathways from numerous cell surface receptors, including receptor tyrosine kinases (RTKs). The decisive factor (ligand, RTKs or both) that controls the recruitment of specific CD44 isoforms is still unknown. We investigated this question by using the EGFR signaling pathway, in which one receptor can be activated by a broad range of ligands. By means of siRNA-mediated downregulation of CD44 expression and blocking experiments, we identified CD44v6 as a co-receptor for EGF- and ER-induced ErbB1 activation and for NRG1-induced ErbB3 and ErbB4 activation. In contrast, TGFα is independent of all CD44 isoforms, even though it addresses the same receptor pairs as EGF. Moreover, the heparin-sulfated CD44v3 isoform is required for HB-EGF-induced EGFR signaling. These data suggest that specific CD44 isoforms are recruited in a ligand-dependent manner as co-receptors in the EGFR signaling pathways and that the specificity is determined by the ligand and not by the receptors themselves. The in vivo relevance of this interplay between CD44 isoforms and EGFR ligands is underlined by the decreased metastatic spreading of mammary carcinomas in mice treated with a CD44v6-specific peptide. Most importantly, we found a clear correlation between the presence of CD44v6/ErbB1 complexes in breast cancer patients and lymph node metastases.

Genome-Wide Analysis of DNA Methylation in Hyperoxia-Exposed Newborn Rat Lung.

PURPOSE: Oxygen therapy is often required to treat newborn infants with respiratory disorders. Prolonged exposure of neonatal rats to hyperoxia reduced alveolar septation, increased terminal air space size, and increased lung fibrosis; these conditions are very similar to those of human bronchopulmonary dysplasia. Epigenetic regulation of gene expression plays a crucial role in bronchopulmonary dysplasia development. METHOD: We reared Sprague-Dawley rat pups in either room air (RA, n = 24) or an atmosphere containing 85% O2 (n = 26) from Postnatal Days 1 to 14. Methylated DNA immunoprecipitation (MeDIP) was used to analyze genome-wide DNA methylation in lung tissues of neonatal rats. Hyperoxia-exposed rats exhibited larger air spaces and thinner septa than RA-exposed rats did on Postnatal Day 14. The rats exposed to hyperoxia exhibited significantly higher mean linear intercepts than did the rats exposed to RA. We applied MeDIP next-generation sequencing for profiling changes in DNA methylation in the rat lungs exposed to hyperoxia and RA. We performed bioinformatics and pathway analyses on the raw sequencing data to identify differentially methylated candidate genes. RESULTS: Our in vivo model revealed that neonatal hyperoxia exposure arrested alveolarization on Postnatal Day 14. We found that the ErbB, actin cytoskeleton, and focal adhesion signaling pathways are epigenetically modulated by exposure to hyperoxia. We demonstrated that hyperoxia exposure contribute in delaying lung development through an epigenetic mechanism by disrupting the expression of genes in lungs that might be involved in alveolarization. CONCLUSIONS: These data indicate that aberrant DNA methylation and deregulation of the actin cytoskeleton and focal adhesion pathways of lung tissues may be involved in the pathophysiology of hyperoxia-induced arrested alveolarization.

High early growth response 1 (EGR1) expression correlates with resistance to anti-EGFR treatment in vitro and with poorer outcome in metastatic colorectal cancer patients treated with cetuximab

Purpose. Biomarkers, such as mutant RAS, predict resistance to anti-EGFR therapy in only a proportion of patients, and hence, other predictive biomarkers are needed. The aims were to identify candidate genes upregulated in colorectal cancer cell lines resistant to anti-EGFR monoclonal antibody treatment, to knockdown (KD) these genes in the resistant cell lines to determine if sensitivity to anti-EGFR antibody was restored, and finally to perform a pilot correlative study of EGR1 expression and outcomes in a cohort of metastatic colorectal cancer (mCRC) patients given cetuximab therapy. Methods. Comparative expression array analysis of resistant cell lines (SW48, COLO-320DM, and SNU-C1) vs sensitive cell lines (LIM1215, CaCo2, and SW948) was performed. The highest up-regulated gene in each resistant cell line was knocked down (KD) using RNA interference, and effect on proliferation was assessed with and without anti-EGFR treatment. Expression of the candidate genes in patients’ tumours treated with cetuximab was assessed by immunohistochemistry; survival analyses were performed comparing high vs low expression. Results. Genes significantly upregulated in resistant cell lines were EGR1 (early growth response protein 1), HBEGF (heparin-binding epidermal growth factor-like growth factor), and AKT3 (AKT serine/threonine kinase 3). KD of each gene resulted in the respective cells being more sensitive to anti-EGFR treatment, suggesting that the resistant phenotype was reversed. In the pilot study of mCRC patients treated with cetuximab, both median PFS (1.38 months vs 6.79 months; HR 2.77 95% CI 1.2-19.4) and median OS (2.59 months vs 9.82 months; HR 3.0 95% CI 1.3-23.2) were significantly worse for those patients with high EGR1 expression. Conclusion. High EGR1 expression may be a candidate biomarker of resistance to anti-EGFR therapy (AU)

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Urinary circulating DNA detection for dynamic tracking of EGFR mutations for NSCLC patients treated with EGFR-TKIs

Purpose. Changes in EGFR profiles of non small cell lung cancer (NSCLC) patients correlates to clinical outcome. Extracting quality tumor tissue remains a challenge for molecular profiling. Our study aims to ascertain the clinical relevance of urinary cell free DNA as an alternative tumor material source. Methods. 150 patients with activating EGFR mutation and received EGFR-TKIs were recruited to participate in the serial monitoring study. Matched primary tumor samples were taken together with blood and urine specimens before the initiation of TKIs. The EGFR mutation testing was performed and quantified using ddPCR. For serial time point measurements, urine and blood samples were extracted at 1-month intervals for duration of 9 months. Results. Urinary ctDNA yielded a close agreement of 88 % on EGFR mutation status when compared to primary tissue at baseline. Almost all samples detected via urine specimens were uncovered in plasma samples. Analysis of urinary cell free DNA at different time points showed a strong correlation to treatment efficacy. Interestingly, a secondary EGFR mutation T790M was detected for 53 % of the patients during monitoring. The results were corroborated with the plasma ctDNA analysis. The T790M+ group had a reduced median survival when compared to the wildtype group. Conclusion. Urinary cell free DNA may be a potential alternative to conventional primary tissue based EGFR mutation testing. Our findings showed that the assay sensitivity was comparable to results from blood plasma. Urinary samples being noninvasive and readily available have clinical utility for monitoring of EGFR TKI treatment (AU)

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[MET receptor inhibition: Hope against resistance to targeted therapies?] / Inhibition du récepteur MET : un espoir dans la lutte contre les résistances aux thérapies ciblées ?

Overcoming the drug resistance remains a crucial issue in cancer treatment. For refractory patients, the use of MET receptor tyrosine kinase inhibitors seems to be hopeful. Indeed, important mechanisms underlying drug resistance argue for association of MET inhibitors with targeted therapies, both on first-line to prevent a primary resistance and on the second line to overcoming acquired resistance. Indeed, met gene amplification is the second most common alteration involved in acquired resistance to anti-epidermal growth factor receptor (EGFR) therapies in non-small cells lung cancer (NSCLC). Hypoxia, for its part, can activate MET transcription and amplifies HGF signaling resulting in MET activation, which could be involved in vascular endothelial growth factor (VEGF) inhibitors escape. In HER2 positive breast cancers, MET amplification may also induce tumor cells a hatch escape, resulting in secondary resistance. Finally, some patients with BRAF mutated melanoma exhibit primary resistance to BRAF inhibition by stromal HGF (ligand of MET) secretion resulting in MET receptor activation. Experimental data highlight the role of MET in primary and secondary resistance and encourage combined treatments including MET inhibitors. In this context, several promising clinical trials are in progress in numerous cancers (NSCLC, melanoma, breast cancer, glioblastoma…) using combination of anti-MET and other specific therapies targeting EGFR, BRAF, VEGF or HER2. This review summarizes the potential benefits that MET inhibition should provide to patients with cancer refractory to targeted therapies.

miRNAs: mediators of ErbB family targeted therapy resistance.

The ErbB/HER tyrosine kinase receptors family plays a key regulatory role in different cellular processes by activating several signaling pathways. In different tumor types, mutations or overexpression of the ErbB family members are a common feature, which led to the development of targeted therapies against this receptors. Although with this kind of treatment we are heading to a more personalized medicine, the development of acquired resistance is still an issue, therefore, several studies focused on discovering the mechanisms behind it. More recently, miRNAs have been described as important mediators of acquired resistance, specifically, acquired resistance to ErbB family targeted therapies. Ultimately, miRNA-based therapeutics using exosomes as a drug delivery model can revolutionize today's approach of cancer treatment.

The hibernating South American marsupial, Dromiciops gliroides, displays torpor-sensitive microRNA expression patterns.

When faced with adverse environmental conditions, the marsupial Dromiciops gliroides uses either daily or seasonal torpor to support survival and is the only known hibernating mammal in South America. As the sole living representative of the ancient Order Microbiotheria, this species can provide crucial information about the evolutionary origins and biochemical mechanisms of hibernation. Hibernation is a complex energy-saving strategy that involves changes in gene expression that are elicited in part by microRNAs. To better elucidate the role of microRNAs in orchestrating hypometabolism, a modified stem-loop technique and quantitative PCR were used to characterize the relative expression levels of 85 microRNAs in liver and skeletal muscle of control and torpid D. gliroides. Thirty-nine microRNAs were differentially regulated during torpor; of these, 35 were downregulated in liver and 11 were differentially expressed in skeletal muscle. Bioinformatic analysis predicted that the downregulated liver microRNAs were associated with activation of MAPK, PI3K-Akt and mTOR pathways, suggesting their importance in facilitating marsupial torpor. In skeletal muscle, hibernation-responsive microRNAs were predicted to regulate focal adhesion, ErbB, and mTOR pathways, indicating a promotion of muscle maintenance mechanisms. These tissue-specific responses suggest that microRNAs regulate key molecular pathways that facilitate hibernation, thermoregulation, and prevention of muscle disuse atrophy.

Exercise training activates neuregulin 1/ErbB signaling and promotes cardiac repair in a rat myocardial infarction model.

AIMS: Exercise training (ET) has a cardioprotective effect and can alter the molecular response to myocardial infarction (MI). The Neuregulin 1 (NRG1)/ErbB signaling plays a critical role in cardiac repair and regeneration in the failing heart. We sought to investigate whether ET following MI could activate the NRG1/ErbB signaling and promote cardiac repair and regeneration. MAIN METHODS: Male Sprague-Dawley rats were used to establish the MI model. Exercise-trained animals were subjected to four weeks of exercise (16m/min, 50min/d, 5d/wk) following the surgery. AG1478 was used as an inhibitor of ErbB (1mg/kg body weight, administered i.v. every other day during the process of training). NRG1/ErbB signaling activation, cardiomyocyte (CM) proliferation and apoptosis were evaluated. KEY FINDINGS: In the exercise-trained rats, NRG1 expression was up-regulated and ErbB/PI3K/Akt signaling was activated compared with the MI group. In addition, ET preserved heart function accompanied with increased numbers of BrdU(+) CMs, PCNA(+) CMs and c-kit(+) cells, and reduced apoptosis level in the MI rats. In contrast, blocking ErbB signaling by AG1478 attenuated the ET-induced cardiac repair and regeneration. SIGNIFICANCE: ET up-regulates NRG1 expression and activates ErbB2, ErbB4 and PI3K/Akt signal transduction to promote cardiac repair through endogenous regeneration. Activation of ErbB may be an underlying mechanism for the ET-induced cardiac repair and regeneration following MI.

A Spectroscopic Approach to Investigate the Molecular Interactions between the Newly Approved Irreversible ErbB blocker "Afatinib" and Bovine Serum Albumin.

The interaction of afatinib (AFB) with bovine serum albumin (BSA) was examined via fluorescence and UV-Vis spectroscopy. Spectrofluorimetric measurements revealed that AFB can strongly quench the BSA intrinsic fluorescence through producing a non-fluorescent complex. This quenching mechanism was thoroughly investigated with regard to the type of quenching, binding constant, number of binding locations and the fundamental thermodynamic parameters. Subsequently, the association constant of AFB with BSA was computed at three different temperatures and was found to range from 7.34 to 13.19 x10(5) L mol(-1). Thermodynamic parameters calculations demonstrated a positive ΔSƟ value with both negative ΔHÏ´ and ΔGÏ´ values for AFB-BSA complex, which in turn infers that a spontaneous binding is taking place with both electrostatic bonding and hydrophobic interactions participating in the binding of AFB and BSA. Similarly, the UV absorption spectra of AFB-BSA system were studied and confirmed the interaction. Conformational alteration of the protein upon binding to AFB was elaborated with the aid of three dimensional fluorescence measurements as well as synchronous fluorescence spectra.

Dysregulation of Neuregulin-1/ErbB signaling in the prefrontal cortex and hippocampus of rats exposed to chronic unpredictable mild stress.

Exposure to chronic stress increases the likelihood of developing depression, but the underlying mechanisms remain equivocal. While recent evidence has indicated that Neuregulin-1 (NRG1) and its ErbB receptors play an essential role in neural development and function, and NRG1 has emerged as a novel modulator involved in the response of brain to stress, there is limited evidence concerning the effects of chronic stress exposure on NRG1/ErbB signaling. To fill this critical gap, we examined the protein expression of NRG1 and ErbB receptors in the brain of rats following chronic unpredictable mild stress (CUMS) exposure. After 6weeks of CUMS procedures, the rats were induced to a depression-like state. The stressed rats displayed elevated expression of NRG1 and phosphorylated ErbB4 (pErbB4) in the prefrontal cortex, whereas ErbB2 and pErbB2 were inhibited. In the hippocampus, CUMS also attenuated activation of the both ErbB receptors and suppressed the downstream Akt and ERK phosphorylation. Meanwhile, administration of sertraline enhanced NRG1/ErbB signaling and partly normalized the stress-induced behavioral changes and the disturbances of NRG1/ErbB system in CUMS rats. Combined, our data firstly showed the aberrant changes of NRG1/ErbB system in the brain of the animal model of depression, providing new evidence for the involvement of NRG1/ErbB pathway in the development and treatment of depression.

N-cadherin promotes epithelial-mesenchymal transition and cancer stem cell-like traits via ErbB signaling in prostate cancer cells.

N-cadherin has been reported to be upregulated and associated with metastasis and poor prognosis in prostate cancer patients, however the underlying mechanism still remains puzzling. In the present study, we found that upregulation of N-cadherin enhanced, while downregulation of N-cadherin impaired the invasion, migration, and epithelial to mesenchymal transition (EMT) of prostate cancer (PCa) cells. Overexpression of N-cadherin increased the efficiency of colony and tumor spheroid formation and the stemness factor expression (including c-Myc, Klf4, Sox2 and Oct4), and vice versa. Furthermore, microarray analysis and western blot analysis mechanistically proved that N-cadherin activated ErbB signaling pathway by upregulating the expression of Grb2, pShc and pERK1/2. Importantly, the regulation of N-cadherin on EMT and stemness was counteracted by lapatinib, a specific ErbB signaling pathway inhibitor. Collectively, these findings demonstrate that N-cadherin regulates EMT and stemness of PCa cells via activating ErbB signaling pathway, which indicates the pivotal role of N-cadherin/ErbB axis in the metastasis of prostate cancer.

Afatinib, an irreversible ErbB family blocker, with protracted temozolomide in recurrent glioblastoma: a case report.

There are few effective treatments for recurrent glioblastoma multiforme (GBM). We present a patient with recurrent GBM who achieved a prolonged response to treatment with afatinib, an irreversible ErbB family blocker, plus temozolomide. A 58-year-old female patient was diagnosed with multifocal primary GBM. After surgical resection, first-line therapy comprised radiotherapy and temozolomide. Following disease progression after 3 temozolomide cycles, the patient entered a phase I/II clinical trial of afatinib (20-40 mg daily for 28 days) plus temozolomide (50 mg/m2 every 21/28 days). Next-generation sequencing analysis of the brain tumor specimen was performed. At the last assessment, 63 treatment cycles had been completed and the patient had survived for ~5 years since recurrence. Significant disease regression was observed after 5 cycles and was maintained during long-term follow-up. Adverse events were consistent with the known tolerability profile of afatinib and were managed by treatment interruption/dose reduction. The patient had several epidermal growth factor receptor (EGFR) aberrations, including gene amplification and EGFRvIII positivity. Three somatic mutations were identified, including an unprecedented extracellular-domain substitution (D247Y). The patient has survived ~6-fold longer than normally expected in patients with recurrent GBM. The complex EGFR genotype may underlie sustained response to afatinib plus temozolomide.