Trastuzumab deruxtecan for treating HER2-positive unresectable or metastatic breast cancer after 1 or more anti-HER2 treatments

Evidence-based recommendations on trastuzumab deruxtecan (Enhertu) for treating HER2-positive unresectable or metastatic breast cancer after 1 or more anti-HER2 treatments in adults. Commercial arrangement There is a managed access agreement, which includes a patient access scheme, for trastuzumab deruxtecan. NHS organisations can get details on the Commercial Access and Pricing (CAP) Portal. Non-NHS organisations can contact commercialaccess@daiichi-sankyo.co.uk for details.

Subcellular distribution and mechanism of action of AL906, a novel and potent EGFR inhibitor rationally designed to be green fluorescent.

To enhance the potency of EGFR inhibitors, we developed a novel strategy that seeks to conjugate EGFR to a bioactive moiety leading to a molecule termed "combi-molecule". In order to mimic the penetration of this type of molecules, based upon previously reported structure activity relationship studies, we designed a new molecule containing a quinazoline moiety tethered to a p-nitrobenzoxadiazole (NBD) moiety [molecular weight (MW) 700]. Despite its size, AL906 growth inhibitory activity was superior to that of the clinical drug gefitinib. Furthermore, AL906 retained significant EGFR inhibitory activity and good cellular penetration with abundant distribution in the perinuclear region of the cells. In an isogenic NIH3T3 transfected cell panel, it selectively inhibited the growth  of the NIH3T3-EGFR and HER2 transfectants. Confocal microscopy analysis revealed that it was capable of penetrating multilayer aggregates although to a lesser extent than FD105, a small inhibitor of EGFR inhibitor of the same class (MW 300). Its ability to inhibit EGFR auto-phosphorylation in monolayer culture was stronger than in the aggregates. The results suggest that our strategy did not negatively affect EGFR inhibitory potency, EGFR selectivity and growth inhibition. However, its molecular size may account for its decreased aggregate penetration when compared with a smaller EGFR inhibitor of the quinazoline class.

Herceptin: A First Assault on Oncogenes that Launched a Revolution.

This year's Lasker Clinical Research Award honors H. Michael Shepard, Dennis J. Slamon, and Axel Ullrich for their invention of Herceptin, the first monoclonal antibody that blocks a cancer-causing protein, and for its development as a life-saving therapy for women with breast cancer.

Rapid screening of drug candidates against EGFR/HER2 signaling pathway using fluorescence assay.

Over the recent decade, the calcium-based assays have gained much popularity in order to discover new drugs. Since breast cancer is the second cause of death in the female population, rapid and effective methods are needed to screen drug compounds with fewer side effects. Human epidermal growth factor receptor 2 (HER2) increases intracellular free Ca2+ on its signaling pathways. In the present study, BT474 cell line, which overexpresses HER2 receptor, was selected and using fura-2-AM, intracellular Ca2+ release was investigated. The changes in the concentration of intracellular Ca2+ were evaluated by variation in the amount of fluorescence intensity. In the presence of epidermal growth factor (EGF), an increase in fluorescence intensity was observed so that after 20 min it raised to the maximum level. After treatment of BT474 cells by lapatinib, as a tyrosine kinase inhibitor (TKI), the signaling pathway of EGFR/HER2 heterodimer was significantly inhibited, which resulted in a decrease in Ca2+ entry into the cytoplasm and fluorescence emission decreased. The IC50 value for the effect of lapatinib on BT474 cells was 113.2 nmol/L. Our results suggest this method is a simple, efficient and specific approach and can potentially be useful for screening new drug candidates against EGFR/HER2 heterodimer signaling pathways. Graphical abstract ᅟ.

Microenvironment-Mediated Mechanisms of Resistance to HER2 Inhibitors Differ between HER2+ Breast Cancer Subtypes.

Extrinsic signals are implicated in breast cancer resistance to HER2-targeted tyrosine kinase inhibitors (TKIs). To examine how microenvironmental signals influence resistance, we monitored TKI-treated breast cancer cell lines grown on microenvironment microarrays composed of printed extracellular matrix proteins supplemented with soluble proteins. We tested ∼2,500 combinations of 56 soluble and 46 matrix microenvironmental proteins on basal-like HER2+ (HER2E) or luminal-like HER2+ (L-HER2+) cells treated with the TKIs lapatinib or neratinib. In HER2E cells, hepatocyte growth factor, a ligand for MET, induced resistance that could be reversed with crizotinib, an inhibitor of MET. In L-HER2+ cells, neuregulin1-ß1 (NRG1ß), a ligand for HER3, induced resistance that could be reversed with pertuzumab, an inhibitor of HER2-HER3 heterodimerization. The subtype-specific responses were also observed in 3D cultures and murine xenografts. These results, along with bioinformatic pathway analysis and siRNA knockdown experiments, suggest different mechanisms of resistance specific to each HER2+ subtype: MET signaling for HER2E and HER2-HER3 heterodimerization for L-HER2+ cells.

A Nanobody Activation Immunotherapeutic that Selectively Destroys HER2-Positive Breast Cancer Cells.

We report a rationally designed nanobody activation immunotherapeutic that selectively redirects anti-dinitrophenyl (anti-DNP) antibodies to the surface of HER2-positive breast cancer cells, resulting in their targeted destruction by antibody-dependent cellular cytotoxicity. As nanobodies are relatively easy to express, stable, can be humanized, and can be evolved to potently and selectively bind virtually any disease-relevant cell surface receptor, we anticipate broad utility of this therapeutic strategy.

Breast cancer therapy and cardiovascular risk: focus on trastuzumab.

Breast cancer is the most common cancer in the UK. Advances in the methods of early diagnosis as well as newer and more effective treatments have led to improvements of disease-free and overall survival over the last decade. Almost one-third of breast cancers present with an aggressive form characterized by increased expression of human epidermal growth receptor 2 (HER2) proteins. A targeted treatment using monoclonal antibodies against HER2 expression such as trastuzumab has been shown to improve survival. Unfortunately, there is a degree of cardiotoxicity associated with these agents, as inhibition of HER2 pathways can also impair cardioprotective pathways. In the present review, we discuss the mechanisms by which trastuzumab might affect vascular homeostasis leading to endothelial dysfunction. We also provide suggestions for future research examining the effects of trastuzumab on the vasculature in breast cancer.

New formulated "DOX-MTX-loaded nanoparticles" down- regulate HER2 gene expression and improve the clinical outcome in OSCCs model in rat: the effect of IV and oral modalities.

BACKGROUND: Oral squamous cell carcinoma (OSCC) remains as one of the most difficult malignancies to control because of its high propensity for local invasion and cervical lymph node dissemination. In this study, we evaluate the efficacy of our novel pH and temperature sensitive doxorubicin-methotrexate-loaded nanoparticles (DOX-MTX NP) in affecting HER2 expression profile in OSCC model in rat. RESULTS: DOX-MTX- nanoparticle complexes caused significant decrease in mRNA level of HER2 compared to untreated cancers (p<0.05) and this finding was more pronounced with the IV mode (p<0.000). Surprisingly, HER2 mRNA was not affected in DOX treated as compared to the control group (p>0.05). On the other hand, in the DOX-MTX NP treated group, fewer tumors characterized with advanced stage and decreased HER2 paralleled improved clinical outcome (P<0.05). Moreover, the effectiveness of the oral route in the group treated with nanodrug accounted for the enhanced bioavailability of nanoparticulated DOX-MTX compared to free DOX. Furthermore, there was no significant difference in mRNA level of HER2 (p>0.05). CONCLUSIONS: Influence of HER2 gene expression is a new feature and mechanism of action observed only in dual action DOX-MTX-NPs treated groups. Down-regulation of HER2 mRNA as a promising marker and prognosticator of OSCC adds to the cytotoxic benefits of DOX in its new formulation. Both oral and IV application of this nanodrug could be used, with no preferences in term of their safety or toxicity. As HER2 is expressed abundantly by a wide spectrum of tumors, i DOX-MTX NPs may be useful for a wide-spectrum of lesions. However, molecular mechanisms underlying HER2 down regulation induced by DOX-MTX NPs remain to be addressed.

Targeted therapy in uterine serous carcinoma: an aggressive variant of endometrial cancer.

Uterine serous carcinoma (USC) is a highly aggressive variant of endometrial cancer. Although it only represents less than 10% of all cases, it accounts for a disproportionate number of deaths from endometrial cancer. Comprehensive surgical staging followed by carboplatin and paclitaxel chemotherapy represents the mainstay of USC therapy. Vaginal cuff brachytherapy is also of potential benefit in USC. Recent whole-exome sequencing studies have demonstrated gain of function of the HER2/NEU gene, as well as driver mutations in the PIK3CA/AKT/mTOR and cyclin E/FBXW7 oncogenic pathways in a large number of USCs. These results emphasize the relevance of these novel therapeutic targets for biologic therapy of chemotherapy-resistant recurrent USC.

Novel cancer therapies: treatments driven by tumour biology.

The traditional view is that treatments within oncology largely consist of chemotherapy, which aims to maximise damage to the rapidly dividing cancer cells but often at the expense of normal cells and overall quality of life for the patient. The development of anticancer drugs has changed from the serendipitous discoveries of the past, to today's purposeful targeting of cancer cells which takes advantage of novel technological developments and a greater understanding of tumour biology. The aim of these new treatments is to affect the essential function of the cancer cell while sparing normal cells, and limiting side effects. The phenotypic characteristics of tumours, such as unregulated growth signalling, development of new vascular systems and the evasion of immune destruction are used to identify potential drug targets. Here we review the clinical evidence and molecular mechanisms for novel therapies that are currently in use and those that are in development.

Cardiotoxicity of novel HER2-targeted therapies.

BACKGROUND: Trastuzumab, an anti-HER2 humanized monoclonal antibody, is the standard treatment for both early and metastatic HER2-positive breast cancer. In addition to other chemotherapeutic agents, trastuzumab significantly improves response rate and survival in HER2-positive early and metastatic breast cancer. Although it is well known that trastuzumab therapy is closely associated with both symptomatic and asymptomatic cardiotoxicity, less is known about novel HER2-targeted therapies. The aim of this review is to discuss the cardiac safety data from recent studies of novel anti-HER2 drugs other than trastuzumab. SCOPE: Novel HER2-targeted therapies showed favorable results in HER2 positive metastatic breast cancer patients. Pubmed database, ASCO and San Antonio Breast Cancer Symposium Meeting abstracts were searched until January 2013 using the following search keywords; 'trastuzumab, trastuzumab cardiotoxicity, HER-2 targeted therapies, lapatinib, pertuzumab, trastuzumab emtansine, afatinib and neratinib'; papers which were considered relevant for the aim of this review were selected by the authors. Lapatinib, pertuzumab, T-DM1, neratinib and afatinib molecules are evaluated in the study. FINDINGS: In a comprehensive analysis, 3689 lapatinib treated patients enrolled in 49 trials; asymptomatic cardiac events were reported in 53 patients (1.4%) and symptomatic grade III and IV systolic dysfunction was observed only in 7 patients (0.2%) treated with lapatinib. In phase I-III trials of pertuzumab, cardiac dysfunction was seen in 4.5-14.5% of patients with pertuzumab treatment and cardiac dysfunction was usually grade I and II. Cardiotoxicity of pertuzumab was usually reported with the trastuzumab combination and no additive cardiotoxicity was reported with addition of pertuzumab to trastuzumab. T-DM1 had a better safety profile compared to trastuzumab, no significant cardiotoxicity was observed with T-DM1 in heavily pre-treated patients. In the EMILIA study, only in 1.7% of patients in the T-DM1 group experienced reduction of left ventricular ejection fraction (LVEF) and grade III LVEF reduction developed only in one patient (0.2%) in the T-DM1 group compared to the lapatinib plus capacitabine group. In phase I-II trials with neratinib no cardiotoxicity was reported whereas cardiotoxicity was seen between 0-5.3% with afatinib treatment. CONCLUSION: Although cardiac toxicity has been reported as an adverse event for novel HER2-targeted therapies, cardiac dysfunction rate of the novel HER2-targeted therapies is significantly lower than the trastuzumab and combination of these agents with trastuzumab did not significantly increase the cardiac adverse events.

Change in HER2 (ERBB2) gene status after taxane-based chemotherapy for breast cancer: polyploidization can lead to diagnostic pitfalls with potential impact for clinical management.

The status of the HER2 (ERBB2) gene in breast cancer is not static and may change among the primary tumor, lymph node metastases, and distant metastases. This status change can be a consequence of the natural evolution of the tumor or can be induced by therapy. The HER2 gene status is, in the majority of cases, established at the moment of diagnosis. After chemotherapy, monitoring HER2 status can be a challenge because of ploidy changes induced by drugs. The cytogeneticist or the pathologist can face real difficulties in distinguishing between a true HER2 amplification and HER2 copy number increase by polyploidization. We performed a HER2 genetic examination by fluorescence in situ hybridization (FISH) of invasive breast cancers before and after taxane treatment. The majority of patients (91%) were HER2-negative both at diagnosis and after treatment. Thirty of 344 patients (9%) whose tumors were initially HER2-negative were found by FISH to have supernumerary HER2 gene copies (up to 15 copies) after neoadjuvant chemotherapy. This HER2 copy increase could not be attributed to true gene amplifications and instead reflected polyploidization events, which presumably affected all chromosomes. Indeed, when we used other FISH probes, we found other gene copy numbers to parallel those of HER2. We recommend careful checking of invasive breast carcinomas by supplementary FISH probes if the copy number of the HER2 gene is >6. This procedure allows the discrimination of specific HER2 gene amplifications and global increases in ploidy.

Overcoming resistance to EGFR inhibitor in head and neck cancer: a review of the literature.

Head and neck squamous cell carcinoma (HNSCC) affects over half a million people worldwide. Despite advances in therapy, only half of the patients are alive in 5 years. Epidermal growth factor receptor (EGFR) is overexpressed in approximately 90% of the tumors, and it is correlated with poor response to treatment and worse outcome. Multiple therapies targeting this pathway have been tested. Cetuximab is the only EGFR inhibitor approved in HNSCC, but response rates are low. More recently, significant interest has focus on identifying mechanisms of acquired and de novo EGFR blockage resistance. Here we review some of these mechanisms and describe strategies to overcome that resistance.

Review of hormonal treatment of breast cancer.

This critical review focuses on the role of steroid hormones and their receptors in the development and treatment of breast cancer, with special reference to estrogen receptors, as well as mechanisms of receptor-ligand interactions, response or resistance to hormonal therapy against breast cancer, in conjunction with other modalities like surgery and chemotherapy. Tamoxifen is used in hormonal treatment of breast cancer for up to five years, depending on the presentation. However, there have been recent developments in hormonal therapy of breast cancer in the last ten years, with the introduction of many different alternative therapies for this condition. A critical review of published articles in Pubmed/Medline, Athens, AJOL, NHS Evidence, Science Direct and Google, relating to hormonal treatment of breast cancer, was undertaken, in order to evaluate the mechanisms of estrogen receptor-ligand interactions, their involvement in the etio-pathogenesis of breast cancer, resistance of breast cancer cells to anti-hormonal agents, as well as ways of treating breast cancer using anti-hormone drugs like tamoxifen. Although tamoxifen is the established drug for hormonal treatment of breast cancer, cases of hormone resistance breast cancer have been described recently in the literature. This can happen from the beginning, or during treatment. Therefore, we aim to examine the causes of resistance to hormonal treatment with a view to understand the options of tackling this problem, and suggest other novel alternative hormonal therapies that can be tried, which may overtake tamoxifen in the future. We also seek to emphasize that hormonal therapy has a definite place in the treatment of breast cancer along with surgery, chemotherapy and radiotherapy, as the disease is often considered to be multi-systemic even from the beginning.

c-erbB2 and c-myb induce mouse oocyte maturation involving activation of maturation promoting factor.

Proto-oncogenes are involved in cell growth, proliferation, and differentiation. In the present study, we investigated the roles and mediating pathways of proto-oncogenes c-erbB(2) and c-myb in mouse oocyte maturation by RT-PCR, real-time quantitative PCR, western blot, and recombinant proto-oncogene protein microinjection. Results showed that both c-erbB(2) and c-myb antisense oligodeoxynucleotides (c-erbB(2) ASODN and c-myb ASODN) inhibited germinal vesicle breakdown and the first polar body extrusion in a dose-dependent manner. However, microinjection of recombinant c-erbB(2) or c-myb protein into germinal vesicle stage oocytes stimulated oocyte meiotic maturation. In addition, the expression of c-erbB(2) and c-myb mRNA was detected in oocytes; and c-erbB(2) ASODN and c-myb ASODN inhibited c-erbB(2) mRNA and c-myb mRNA expression, respectively. Maturation promoting factor (MPF) inhibitor roscovitine did not affect the expression of c-erbB(2) mRNA and c-myb mRNA, but blocked the effects of recombinant c-erbB(2) and c-myb protein-induced oocyte maturation. Further, cyclin B1 protein expression in oocytes was remarkably inhibited by c-erbB(2) ASODN, c-myb ASODN, and roscovitine. Nonsense tat ODN had no effect on the expression of c-erbB(2), c-myb, and cyclin B1. These results suggest that c-erbB(2) and c-myb may induce oocyte maturation through mediating a pathway involving the activation of MPF.

Eficácia e segurança de trastuzumabe no tratamento de câncer de mama / Efficacy and safety of trastuzumab in the treatment of breast cancer / Eficacia y seguridad de trastuzumab en el tratamiento del cáncer de mama

TECNOLOGIA: Trastuzumabe. INDICAÇÃO: Câncer de mama metastático com superexpressão de HER-2. CARACTERIZAÇÃO DA TECNOLOGIA: Trastuzumabe é um anticorpo monoclonal humanizado derivado de DNA recombinante, que se liga ao domínio extracelular do receptor do fator de crescimento epidérmico humano, HER-2. Esse anticorpo bloqueia o ligante natural e infra-regula o receptor. Sua utilização isolada ou em associação com quimioterápicos proporciona desaceleração na progressão do câncer de mama metastático HER-2 positivo. PERGUNTA: O uso do trastuzumabe é eficaz e seguro no tratamento de câncer de mama metastático em mulheres com superexpressão de HER-2? BUSCA E ANÁLISE DE EVIDÊNCIAS CIENTÍFICAS: Foram pesquisadas as bases The Cochrane Library, Centre for Reviews and Dissemination (CRD), Tripdatabase, Medline via Pubmed e LILACS, objetivando-se encontrar revisões sistemáticas (RS) de ensaios clínicos que comparassem trastuzumabe a outras opções terapêuticas para o tratamento de câncer de mama metastático. Foram selecionados somente os estudos publicados em inglês, português ou espanhol. RESUMO DOS RESULTADOS DOS ESTUDOS SELECIONADOS: Foram selecionadas 9 RS. De maneira geral, as quimioterapias combinadas com trastuzumabe apresentam melhores resultados que a quimioterapia isolada, quanto a sobrevida global, sobrevida livre de doença e tempo de progressão da doença. Na RS que avalia a combinação do trastuzumabe com antraciclina verifica-se maior risco de disfunção cardíaca. RECOMENDAÇÕES: O uso de trastuzumabe em combinação com paclitaxel ou docetaxel como terapia de primeira linha para mulheres com câncer de mama metastático com superexpressão de HER-2 é recomendado.(AU)

TECHNOLOGY: Trastuzumab. INDICATION: Metastatic breast cancer overexpressing HER-2. CHARACTERIZATION OF THE TECHNOLOGY: Trastuzumab is a humanized monoclonal antibody derived from recombinant DNA, which binds to the receptor extracellular domain of human epidermal growth factor, HER2. This antibody blocks the natural ligand and infra-regulates the receptor. Its use alone or in combination with chemotherapy provides deceleration in the progression of metastatic breast cancer HER-2 positive. QUESTION: The use of trastuzumab is effective and safe in the treatment of metastatic breast cancer in women overexpressing HER-2? SEARCH AND ANALYSIS OF SCIENTIFIC EVIDENCE: Databases were searched The Cochrane Library, Centre for Reviews and Dissemination (CRD), Tripdatabase, Medline (via Pubmed) and LILACS, aiming to find systematic reviews (SR) of clinical trials that compared trastuzumab to other options therapies for the treatment of metastatic breast cancer. We selected only those studies published in English, Portuguese or Spanish. SUMMARY OF RESULTS OF SELECTED STUDIES: 9 SR were selected. In general, the chemotherapy combined with trastuzumab have better outcomes than chemotherapy alone, the overall survival, disease-free survival and time to disease progression. In the SR, which evaluates the combination of trastuzumab with anthracycline there is increased risk of cardiac dysfunction. RECOMMENDATIONS: The use of trastuzumab in combination with paclitaxel or docetaxel as first-line therapy for women with metastatic breast cancer overexpressing HER-2 is recommended.(AU)

TECNOLOGÍA: Trastuzumab. INDICACIÓN: Cáncer de mama metastásico con sobreexpresión de HER-2. CARACTERIZACIÓN DE LA TECNOLOGÍA: Trastuzumab es un anticuerpo monoclonal humanizado derivado de ADN recombinante, que se une al dominio extracelular del receptor del factor de crecimiento epidérmico humano de HER-2. Este anticuerpo bloquea el ligando natural e infra-regula el receptor. Su uso solo o en combinación con agentes quimioterapéuticos proporciona ralentización de la progresión de cáncer metastásico de mama HER-2 positivo. PREGUNTA: ¿El uso de trastuzumab es eficaz y seguro en el tratamiento del cáncer de mama metastásico en mujeres con sobreexpresión de HER-2? BÚSQUEDA Y ANÁLISIS DE LA EVIDENCIA CIENTÍFICA: Se hicieron búsquedas en las bases de datos The Cochrane Library, Centre for Reviews and Dissemination (CRD), Tripdatabase, Medline (via Pubmed) y en LILACS para encontrar revisiones sistemáticas (RS) de ensayos clínicos que compararon trastuzumab a otras opiciones terapéuticas para el tratamiento de cáncer de mama. Fueron seleccionados estudios en inglés, portugués y español. RESUMEN DE LOS RESULTADOS DE LOS ESTUDIOS SELECCIONADOS: Se seleccionaron 9 RS. En general, la combinación de quimioterapia con trastuzumab mostró mejores resultados que la quimioterapia sola, como la supervivencia global, tiempo libre de enfermedad y la tasa de supervivencia de progresión de la enfermedad. En las RS que evaluaron la combinación de trastuzumab con antraciclina hay mayor riesgo de disfunción cardíaca. RECOMENDACIONES: Se recomienda el uso de trastuzumab en combinación con paclitaxel o docetaxel como terapia de primera línea para las mujeres con cáncer de mama metastásico con sobreexpresión de HER-2.(AU)

Determining true HER2 gene status in breast cancers with polysomy by using alternative chromosome 17 reference genes: implications for anti-HER2 targeted therapy.

PURPOSE: The ratio of human epidermal growth factor receptor 2 (HER2) to CEP17 by fluorescent in situ hybridization (FISH) with the centromeric probe CEP17 is used to determine HER2 gene status in breast cancer. Increases in CEP17 copy number have been interpreted as representing polysomy 17. However, pangenomic studies have demonstrated that polysomy 17 is rare. This study tests the hypothesis that the use of alternative chromosome 17 reference genes might more accurately assess true HER2 gene status. PATIENTS AND METHODS: In all, 171 patients with breast cancer who had HER2 FISH that had increased mean CEP17 copy numbers (> 2.6) were selected for additional chromosome 17 studies that used probes for Smith-Magenis syndrome (SMS), retinoic acid receptor alpha (RARA), and tumor protein p53 (TP53) genes. A eusomic copy number exhibited in one or more of these loci was used to calculate a revised HER2-to-chromosome-17 ratio by using the eusomic gene locus as the reference. RESULTS: Of 132 cases classified as nonamplified on the basis of their HER2:CEP17 ratios, 58 (43.9%) were scored as amplified by using alternative chromosome 17 reference gene probes, and 13 (92.9%) of 14 cases scored as equivocal were reclassified as amplified. Among the cases with mean HER2 copy number of 4 to 6, 41 (47.7%) of 86 had their HER2 gene status upgraded from nonamplified to amplified, and four (4.7%) of 86 were upgraded from equivocal to amplified. CONCLUSION: Our results support the findings of recent pangenomic studies that true polysomy 17 is uncommon. Additional FISH studies that use probes to the SMS, RARA, and TP53 genes are an effective way to determine the true HER2 amplification status in patients with polysomy 17 and they have important potential implications for guiding HER2-targeted therapy in breast cancer.

Magnolol down-regulates HER2 gene expression, leading to inhibition of HER2-mediated metastatic potential in ovarian cancer cells.

Overexpression of the HER2 oncogene contributes to tumor cell invasion, metastasis and angiogenesis and correlates with poor prognosis. Magnolol has been reported to exhibit anti-tumor activities. However, the molecular mechanism of action of magnolol has not been investigated in HER2-positive cancer cells. Therefore, we examined the anti-cancer effects of magnolol on HER2-overexpressing ovarian cancer cells. Magnolol treatment caused a dose-dependent inhibition of HER2 gene expression at the transcriptional level, potentially in part through suppression of NF-κB activation. Treatment of HER2-overexpressing ovarian cancer cells with magnolol down-regulated the HER2 downstream PI3K/Akt signaling pathway, and suppressed the expression of downstream target genes, vascular endothelial growth factor (VEGF), matrix metalloproteinase 2 (MMP2) and cyclin D1. Consistently, magnolol-mediated inhibition of MMP2 activity could be prevented by co-treatment with epidermal growth factor. Migration assays revealed that magnolol treatment markedly reduced the motility of HER2-overexpressing ovarian cancer cells. Furthermore, magnolol-induced apoptosis in HER2-overexpressing ovarian cancer cells was characterized by the up-regulation of cleaved poly(ADP-ribose) polymerase (PARP) and activated caspase 3. These findings suggest that magnolol may act against HER2 and its downstream PI3K/Akt/mTOR-signaling network, thus resulting in suppression of HER2-mediated transformation and metastatic potential in HER2-overexpressing ovarian cancers. These results provide a novel mechanism to explain the anti-cancer effect of magnolol.

Alteration of topoisomerase II-alpha gene in human breast cancer: association with responsiveness to anthracycline-based chemotherapy.

PURPOSE: Approximately 35% of HER2-amplified breast cancers have coamplification of the topoisomerase II-alpha (TOP2A) gene encoding an enzyme that is a major target of anthracyclines. This study was designed to evaluate whether TOP2A gene alterations may predict incremental responsiveness to anthracyclines in some breast cancers. METHODS: A total of 4,943 breast cancers were analyzed for alterations in TOP2A and HER2. Primary tumor tissues from patients with metastatic breast cancer treated in a trial of chemotherapy plus/minus trastuzumab were studied for amplification/deletion of TOP2A and HER2 as a test set followed by evaluation of malignancies from two separate, large trials for changes in these same genes as a validation set. Association between these alterations and clinical outcomes was determined. RESULTS: Test set cases containing HER2 amplification treated with doxorubicin and cyclophosphamide (AC) plus trastuzumab, demonstrated longer progression-free survival compared to those treated with AC alone (P = .0002). However, patients treated with AC alone whose tumors contain HER2/TOP2A coamplification experienced a similar improvement in survival (P = .004). Conversely, for patients treated with paclitaxel, HER2/TOP2A coamplification was not associated with improved outcomes. These observations were confirmed in a larger validation set, where HER2/TOP2A coamplification was again associated with longer survival when only anthracycline-containing chemotherapy was used for treatment compared with outcome in HER2-positive cancers lacking TOP2A coamplification. CONCLUSION: In a study involving nearly 5,000 breast malignancies, both test set and validation set demonstrate that TOP2A coamplification, not HER2 amplification, is the clinically useful predictive marker of an incremental response to anthracycline-based chemotherapy. Absence of HER2/TOP2A coamplification may indicate a more restricted efficacy advantage for breast cancers than previously thought.