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G M Bernardo,
G Bebek,
C L Ginther,
S T Sizemore,
K L Lozada,
J D Miedler,
L A Anderson,
A K Godwin,
F W Abdul-Karim, D J Slamon,
R A Keri
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ABSTRACT: Breast cancer is a heterogeneous disease that comprises multiple subtypes. Luminal subtype tumors confer a more favorable patient prognosis, which is, in part, attributed to estrogen receptor (ER)-α positivity and antihormone responsiveness. Expression of the forkhead box transcription factor, FOXA1, similarly correlates with the luminal subtype and patient survival, but is also present in a subset of ER-negative tumors. FOXA1 is also consistently expressed in luminal breast cancer cell lines even in the absence of ER. In contrast, breast cancer cell lines representing the basal subtype do not express FOXA1. To delineate an ER-independent role for FOXA1 in maintaining the luminal phenotype, and hence a more favorable prognosis, we performed expression microarray analyses on FOXA1-positive and ER-positive (MCF7, T47D), or FOXA1-positive and ER-negative (MDA-MB-453, SKBR3) luminal cell lines in the presence or absence of transient FOXA1 silencing. This resulted in three FOXA1 transcriptomes: (1) a luminal signature (consistent across cell lines), (2) an ER-positive signature (restricted to MCF7 and T47D) and (3) an ER-negative signature (restricted to MDA-MB-453 and SKBR3). Gene set enrichment analyses revealed FOXA1 silencing causes a partial transcriptome shift from luminal to basal gene expression signatures. FOXA1 binds to a subset of both luminal and basal genes within luminal breast cancer cells, and loss of FOXA1 increases enhancer RNA transcription for a representative basal gene (CD58). These data suggest FOXA1 directly represses a subset of basal signature genes. Functionally, FOXA1 silencing increases migration and invasion of luminal cancer cells, both of which are characteristics of basal subtype cells. We conclude FOXA1 controls plasticity between basal and luminal breast cancer cells, not only by inducing luminal genes but also by repressing the basal phenotype, and thus aggressiveness. Although it has been proposed that FOXA1-targeting agents may be useful for treating luminal tumors, these data suggest that this approach may promote transitions toward more aggressive cancers.Oncogene advance online publication, 5 March 2012; doi:10.1038/onc.2012.62.
Oncogene 03/2012; · 6.37 Impact Factor
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G E Konecny,
R Glas,
J Dering,
K Manivong,
J Qi,
R S Finn,
G R Yang,
K-L Hong,
C Ginther,
B Winterhoff,
G Gao,
J Brugge, D J Slamon
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ABSTRACT: Here, we explore the therapeutic potential of dasatinib, a small-molecule inhibitor that targets multiple cytosolic and membrane-bound tyrosine kinases, including members of the Src kinase family, EphA2, and focal adhesion kinase for the treatment of ovarian cancer.
We examined the effects of dasatinib on proliferation, invasion, apoptosis, cell-cycle arrest, and kinase activity using a panel of 34 established human ovarian cancer cell lines. Molecular markers for response prediction were studied using gene expression profiling. Multiple drug effect/combination index (CI) isobologram analysis was used to study the interactions with chemotherapeutic drugs.
Concentration-dependent anti-proliferative effects of dasatinib were seen in all ovarian cancer cell lines tested, but varied significantly between individual cell lines with up to a 3 log-fold difference in the IC(50) values (IC(50) range: 0.001-11.3 micromol l(-1)). Dasatinib significantly inhibited invasion, and induced cell apoptosis, but less cell-cycle arrest. At a wide range of clinically achievable drug concentrations, additive and synergistic interactions were observed for dasatinib plus carboplatin (mean CI values, range: 0.73-1.11) or paclitaxel (mean CI values, range: 0.76-1.05). In this study, 24 out of 34 (71%) representative ovarian cancer cell lines were highly sensitive to dasatinib, compared with only 8 out of 39 (21%) representative breast cancer cell lines previously reported. Cell lines with high expression of Yes, Lyn, Eph2A, caveolin-1 and 2, moesin, annexin-1, and uPA were particularly sensitive to dasatinib.
These data provide a clear biological rationale to test dasatinib as a single agent or in combination with chemotherapy in patients with ovarian cancer.
British Journal of Cancer 11/2009; 101(10):1699-708. · 5.04 Impact Factor
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G E Konecny,
N Venkatesan,
G Yang,
J Dering,
C Ginther,
R Finn,
M Rahmeh,
M Schoenberg Fejzo,
D Toft,
S-W Jiang, D J Slamon,
K C Podratz
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ABSTRACT: In this study, we explore the therapeutic potential of lapatinib a selective inhibitor of both the EGFR and HER2 tyrosine kinases for the treatment of endometrial cancer. The effect of lapatinib on tumour cell growth and receptor activation was studied in a panel of human endometrial cancer cell lines. Candidate molecular markers predicting sensitivity were assessed by baseline gene expression profiling, ELISA, and western blot analyses. Multiple drug effect/combination index (CI) isobologram analysis was used to study the interactions between chemotherapeutic drugs and lapatinib. Concentration-dependent anti-proliferative effects of lapatinib were seen in all endometrial cancer cell lines tested, but varied significantly between individual cell lines (IC(50) range: 0.052-10.9 micromol). HER2 overexpression or increased expression of EGFR was significantly associated with in vitro sensitivity (P=0.024 or 0.011, respectively). Lapatinib exerts growth inhibition in a PTEN-independent manner. Sensitive cell lines also exhibited increased expression of EGFR ligands or HER3. In contrast, lapatinib-resistant cell lines exhibited high androgen receptor (AR) levels or epithelial-to-mesenchymal transition (post-EMT) features. In endometrial cancer cells, at a wide range of clinically achievable drug concentrations, additive and synergistic interactions were observed for lapatinib plus carboplatin, paclitaxel, docetaxel, and doxorubicin. These observations provide a clear biologic rational to test lapatinib as a single agent or in combination with chemotherapy in endometrial cancer with HER2 overexpression. Expression of EGFR, its ligands, HER3, AR, and post-EMT markers warrant further evaluation to help define patients with HER2-nonoverexpressing endometrial cancer most likely to benefit from lapatinib.
British Journal of Cancer 04/2008; 98(6):1076-84. · 5.04 Impact Factor
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B M Ryan,
G E Konecny,
S Kahlert,
H-J Wang,
M Untch,
G Meng,
M D Pegram,
K C Podratz,
J Crown, D J Slamon,
M J Duffy
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ABSTRACT: Survivin, a novel inhibitor of apoptosis, is one of the most cancer-specific proteins identified to date. In this study we (a) evaluated the association between survivin and HER2, vascular endothelial growth factor (VEGF) and uPA/PAI-1 expression and (b) defined its effect on clinical outcome in a large breast cancer patient cohort.
Survivin expression was measured by ELISA in primary breast cancer tissue extracts from 420 patients with long-term clinical follow-up.
Survivin was detected in 378 (90%) of the 420 primary breast cancer cases. Increased survivin levels were significantly associated with high nuclear grade (P < 0.0001), negative hormone receptor status (P = 0.0028), HER2 overexpression (P = 0.0094), VEGF expression (P < 0.0001), high uPA (P = 0.0002) and PAI-1 levels (P = 0.0002). Using the 25th percentile (1.4 ng/mg) as a cut-off point, patients expressing elevated survivin had a significantly worse disease-free survival (DFS: P = 0.0007, RR 1.97) and overall survival (OS: P = 0.0009, RR 2.11) compared with patients expressing lower levels of survivin. In multivariate analysis, this prognostic value of survivin was independent of both traditional and novel clinicopathologic factors for both DFS (P = 0.0076, RR 1.72) and OS (P = 0.0155, RR 1.76).
The independent prognostic relevance of survivin, when combined with previous data from model systems implicating survivin in the inhibition of apoptosis, suggests that survivin may be a suitable target for future therapeutic strategies.
Annals of Oncology 04/2006; 17(4):597-604. · 6.43 Impact Factor
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ABSTRACT: A variety of eucaryotic polypeptide growth factors are synthesized as transmembrane precursors. Many of these precursors are released from plasma membranes by proteolytic cleavage and converted into soluble mature proteins. A number of studies, however, indicate that bound growth factor precursors can be biologically active, suggesting a role for these membrane-associated ligands in cell-cell communication. Secreted heregulin is a 45-kDa growth factor with homology to epidermal growth factor. This growth factor binds directly to HER-3 and HER-4 and activates heterodimeric receptor complexes composed of the type I receptor tyrosine kinases, i.e. HER-1, HER-2, HER-3, and HER-4. Heregulin was originally detected in the conditioned medium of the human breast cancer cell line MDA-MB-231 and purified based on its ability to stimulate phosphorylation of p185(HER-2/neu). In the current study, the biologic activity of plasma membrane-anchored heregulin was evaluated in human breast cells. Transmembrane heregulin binds to cells expressing p180(HER-3), induces p185(HER-2/neu) phosphorylation, and increases DNA synthesis in cells overexpressing the HER-2/neu gene product. In addition, when cells containing heregulin receptors are co-cultured with heregulin-producing cells, specific in vivo associations are observed. This study demonstrates that transmembrane heregulin is functionally active and suggest it is capable of playing a role in cell-cell communication and subsequent signal transduction in vivo.
Journal of Biological Chemistry 12/2001; 276(47):44099-107. · 4.77 Impact Factor
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ABSTRACT: Tissue microarray technology is a new method used to analyze several hundred tumor samples on a single slide allowing high throughput analysis of genes and proteins on a large cohort. The original methodology involves coring tissues from paraffin-embedded tissue donor blocks and placing them into a single paraffin block. One difficulty with paraffin-embedded tissue relates to antigenic changes in proteins and mRNA degradation induced by the fixation and embedding process. We have modified this technology by using frozen tissues embedded in OCT compound as donor samples and arraying the specimens into a recipient OCT block. Tumor tissue is not fixed before embedding, and sections from the array are evaluated without fixation or postfixed according to the appropriate methodology used to analyze a specific gene at the DNA, RNA, and/or protein levels. While paraffin tissue arrays can be problematic for immunohistochemistry and for RNA in situ hybridization analyses, this method allows optimal evaluation by each technique and uniform fixation across the array panel. We show OCT arrays work well for DNA, RNA, and protein analyses, and may have significant advantages over the original technology for the assessment of some genes and proteins by improving both qualitative and quantitative results.
American Journal Of Pathology 12/2001; 159(5):1645-50. · 4.89 Impact Factor
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D J Slamon,
B Leyland-Jones,
S Shak,
H Fuchs,
V Paton,
A Bajamonde,
T Fleming,
W Eiermann,
J Wolter,
M Pegram,
J Baselga,
L Norton
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ABSTRACT: The HER2 gene, which encodes the growth factor receptor HER2, is amplified and HER2 is overexpressed in 25 to 30 percent of breast cancers, increasing the aggressiveness of the tumor.
We evaluated the efficacy and safety of trastuzumab, a recombinant monoclonal antibody against HER2, in women with metastatic breast cancer that overexpressed HER2. We randomly assigned 234 patients to receive standard chemotherapy alone and 235 patients to receive standard chemotherapy plus trastuzumab. Patients who had not previously received adjuvant (postoperative) therapy with an anthracycline were treated with doxorubicin (or epirubicin in the case of 36 women) and cyclophosphamide alone (138 women) or with trastuzumab (143 women). Patients who had previously received adjuvant anthracycline were treated with paclitaxel alone (96 women) or paclitaxel with trastuzumab (92 women).
The addition of trastuzumab to chemotherapy was associated with a longer time to disease progression (median, 7.4 vs. 4.6 months; P<0.001), a higher rate of objective response (50 percent vs. 32 percent, P<0.001), a longer duration of response (median, 9.1 vs. 6.1 months; P<0.001), a lower rate of death at 1 year (22 percent vs. 33 percent, P=0.008), longer survival (median survival, 25.1 vs. 20.3 months; P=0.01), and a 20 percent reduction in the risk of death. The most important adverse event was cardiac dysfunction of New York Heart Association class III or IV, which occurred in 27 percent of the group given an anthracycline, cyclophosphamide, and trastuzumab; 8 percent of the group given an anthracycline and cyclophosphamide alone; 13 percent of the group given paclitaxel and trastuzumab; and 1 percent of the group given paclitaxel alone. Although the cardiotoxicity was potentially severe and, in some cases, life-threatening, the symptoms generally improved with standard medical management.
Trastuzumab increases the clinical benefit of first-line chemotherapy in metastatic breast cancer that overexpresses HER2.
New England Journal of Medicine 04/2001; 344(11):783-92. · 53.30 Impact Factor
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C Vogel,
M A Cobleigh,
D Tripathy,
J C Gutheil,
L N Harris,
L Fehrenbacher, D J Slamon,
M Murphy,
W F Novotny,
M Burchmore,
S Shak,
S J Stewart
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ABSTRACT: Following confirmation of the appropriate dosage, safety and potential efficacy of Herceptin(trastuzumab) in small-scale phase I and II trials involving patients with refractory disease, a large trial was conducted in 222 patients with breast cancer who had relapsed after one or two chemotherapy regimens for their metastatic disease. The results showed a positive and durable overall response rate (15% according to a response evaluation committee (REC) assessment) using trastuzumab monotherapy (initial dose 4 mg/kg intravenously (i.v.) followed by 2 mg/kg i.v. weekly). In another recently completed phase II trial, 113 patients were randomised to two dose levels (initial dose of 4 mg/kg i.v. dose followed by 2 mg/kg i.v. weekly, or initial dose of 8 mg/kg followed by 4 mg/kg i.v. weekly) of single-agent trastuzumab as first-line therapy for metastatic disease. The preliminary overall response rate was 23% based on investigator assessment, and tolerability was excellent as in previous trials; efficacy was similar in both dose groups, but the side-effects tended to be more frequent in the higher dose group. The preferred dosage is therefore the same as that currently recommended, i.e. an initial dose of 4 mg/kg i.v. followed by 2 mg/kg weekly i.v. until disease progression.
European Journal of Cancer 02/2001; 37 Suppl 1:S25-9. · 5.54 Impact Factor
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ABSTRACT: Previous studies have shown a synergistic interaction between trastuzumab (Herceptin; Genentech, Inc, South San Francisco, CA) and the cytotoxic drug cisplatin in human breast cancer cells. To define the nature of the interaction between trastuzumab and other classes of cytotoxic drugs, we applied multiple drug effect/combination index isobologram analysis to a variety of chemotherapeutic drug/trastuzumab combinations in vitro. Synergistic interactions at clinically relevant drug concentrations were observed for trastuzumab in combination with cisplatin, docetaxel, thiotepa, 4-OH cyclophosphamide, vinorelbine, and etoposide. Additive cytotoxic effects were observed with trastuzumab plus doxorubicin, paclitaxel, methotrexate, and vinblastine. One drug, 5-fluorouracil was found to be antagonistic with trastuzumab in vitro. In vivo drug/trastuzumab studies were conducted with HER-2/neu-transfected MCF7 human breast cancer xenografts in athymic mice. Combinations of trastuzumab plus cisplatin, docetaxel, cyclophosphamide, doxorubicin, paclitaxel, methotrexate, etoposide, and vinblastine in vivo resulted in a significant reduction in xenograft volume compared to chemotherapy-alone controls (P < .05). The synergistic interaction of trastuzumab with specific chemotherapeutic agents suggests rational combinations for testing in human clinical trials.
Seminars in Oncology 01/2001; 27(6 Suppl 11):21-5; discussion 92-100. · 3.50 Impact Factor
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ABSTRACT: Delineation of downstream signal transduction pathways is important for determining which intracellular signals contribute to the malignant phenotype of cancer cells. In this review, we discuss current methodologies used to study cell signaling. A number of factors that may influence the specificity of signaling will also be taken into consideration. Furthermore, because the HER-2 receptor is amplified and overexpressed in ovarian cancers, we refer to this receptor and its downstream signaling pathways as model systems throughout this review.
Methods in molecular medicine 01/2001; 39:555-65.
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C L Vogel,
M A Cobleigh,
D Tripathy,
J C Gutheil,
L N Harris,
L Fehrenbacher, D J Slamon,
M Murphy,
W F Novotny,
M Burchmore,
S Shak,
S J Stewart
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ABSTRACT: The pivotal phase II and III Herceptin trials proved the efficacy and safety of second- or third-line single-agent Herceptin and first-line Herceptin in combination with chemotherapy, respectively. In the current trial, 114 patients were randomized to one of two dose groups of first-line Herceptin monotherapy: standard dose of 4 mg/ kg initial dose followed by 2 mg/kg intravenous (i.v.) weekly; or high dose of 8 mg/kg initial dose followed by 4 mg/kg i.v. weekly. The regimen was generally well tolerated. A similar incidence of adverse events was demonstrated in the two dose groups with the possible exception of acute infusion-related events such as fever and chills as well as rash and dyspnea, which appear to be more prevalent in the higher dose group. The overall response rate was 26% and response rates were similar between the two dose groups (24% for the standard Herceptin dose group and 28% for the high Herceptin dose group). Subgroup analysis determined a higher response rate in IHC 3+ patients (35%) and FISH-positive patients (41%). When women with stable disease for > or =6 months were included with responders, the clinical benefit rate in IHC 3+ patients was 47%. Median survival was 24.4 months, which is comparable with the survival rate seen in the pivotal phase III combination trial (25 months). Therefore, single-agent Herceptin is an important new option for the first-line treatment of HER2-positive metastatic breast cancer patients.
Oncology 01/2001; 61 Suppl 2:37-42. · 2.27 Impact Factor
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ABSTRACT: To compare the efficacy of fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) in detecting the HER-2/neu alteration in human breast cancer.
Unselected stage I, II, and III breast cancer patients (N = 900) were tested for HER-2/neu gene amplification by FISH in paraffin-embedded, formalin-fixed archival material. Of these samples, 856 were tested for HER-2/neu overexpression by non-antigen-retrieval IHC with the polyclonal antibody R60, the sensitivity and specificity of which was preliminarily compared with the United States Food and Drug Administration-approved HercepTest (Dako Corp, Carpinteria, CA). Patient survival was analyzed in relation to the presence of the HER-2/neu alteration as determined by these two methodologies.
A total of 189 (21%) of 900 patients were positive by FISH and 147 (17.2%) of 856 were positive by IHC. This discrepancy is consistent with expected loss of IHC sensitivity associated with tissue fixation/embedding. The HercepTest did not improve sensitivity and introduced false positives. Comparison of R60-based IHC with FISH demonstrates that patient survival is associated progressively to gene amplification level as determined by FISH, whereas for IHC an association is found only in the highest (3+) immunostaining group. Among FISH-negative tumors, 45 (6.6%) of 678 were IHC-positive, with a survival probability similar to that of FISH-negative/IHC-negative cases; FISH-positive/IHC-negative patients have a survival probability similar to that of FISH-positive/IHC-positive cases.
IHC does not consistently discriminate patients likely to have a poor prognosis, whereas FISH provides superior prognostic information in segregating high-risk from lower-risk beast cancers. HER-2/neu protein overexpression in the absence of gene amplification occurs infrequently in breast cancer, in which case, patient outcome is similar to that of patients without the alteration.
Journal of Clinical Oncology 12/2000; 18(21):3651-64. · 18.37 Impact Factor
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ABSTRACT: The safety and efficacy of administering ex vivo expanded peripheral blood progenitor cells (PBPC) to patients with breast cancer who undergo high-dose chemotherapy and PBPC transplantation was investigated. Unselected PBPC were cultured in gas-permeable bags containing 1-L serum-free media, granulocyte colony-stimulating factor, stem cell factor, and pegylated megakaryocyte growth and development factor for 9 days. Cell dose cohorts were assigned to have between 2 and 24 x 10(9) PBPC cultured at 1, 2, or 3 x 10(6) cells/mL. Twenty-four patients received high-dose chemotherapy followed by infusion of the cultured PBPC and at least 5 x 10(6) CD34(+) uncultured cryopreserved PBPC per kilogram. No toxicities resulted from infusions of the ex vivo expanded PBPC. The study patients had shorter times to neutrophil (P =.0001) and platelet (P =.01) recovery and fewer red cell transfusions (P =.02) than 48 historical controls who received the same conditioning regimen and posttransplantation care and at least 5 x 10(6) CD34(+) PBPC per kilogram. Improvements in all these endpoints were significantly correlated with the expanded cell dose. Nine of 24 (38%) patients recovered neutrophil counts above 500/microL by day 5 or 6 after transplantation, whereas none of the controls had neutrophil recovery before the eighth day. Seven (29%) patients had neutropenia for 3 or fewer days, and 9 (38%) patients did not experience neutropenic fevers or require broad-spectrum antibiotics. Therefore, ex vivo expanded PBPC are capable of ameliorating posttransplantation neutropenia, thrombocytopenia, and anemia in patients receiving high-dose chemotherapy.
Blood 11/2000; 96(7):2385-90. · 9.90 Impact Factor
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Cancer treatment and research 02/2000; 103:57-75.
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ABSTRACT: We present an approach for evaluating the efficacy of combination antitumor agent schedules that accounts for order and timing of drug administration. Our model-based approach compares in vivo tumor volume data over a time course and offers a quantitative definition for additivity of drug effects, relative to which synergism and antagonism are interpreted. We begin by fitting data from individual mice receiving at most one drug to a differential equation tumor growth/drug effect model and combine individual parameter estimates to obtain population statistics. Using two null hypotheses: (i) combination therapy is consistent with additivity or (ii) combination therapy is equivalent to treating with the more effective single agent alone, we compute predicted tumor growth trajectories and their distribution for combination treated animals. We illustrate this approach by comparing entire observed and expected tumor volume trajectories for a data set in which HER-2/neu-overexpressing MCF-7 human breast cancer xenografts are treated with a humanized, anti-HER-2 monoclonal antibody (rhuMAb HER-2), doxorubicin, or one of five proposed combination therapy schedules.
Proceedings of the National Academy of Sciences 12/1999; 96(23):13023-8. · 9.68 Impact Factor
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ABSTRACT: The heregulins are a family of ligands with ability to induce phosphorylation of the p185HER-2/neu receptor. Various investigators have reported a variety of responses of mouse and human breast and ovarian cells to this family of ligands including growth stimulation, growth inhibition, apoptosis and induction of differentiation in cells expressing the HER-2/neu receptor. Some of the disparity in the literature has been attributed to variations in the cell lines studied, ligand dose applied, methodologies utilized or model system evaluated (i.e. in vitro or in vivo). To evaluate the effects of heregulin on normal and malignant human breast and ovarian epithelial cells expressing known levels of the HER-2/neu receptor, this report presents the use of several different assays, performed both in vitro and in vivo, in vitro proliferation assays, direct cell counts, clonogenicity under anchorage-dependent and anchorage-independent conditions, as well as the in vivo effects of heregulin on human cells growing in nude mice to address heregulin activity. Using a total of five different biologic assays in nine different cell lines, across two different epithelia and over a one log heregulin dose range, we obtained results that clearly indicate a growth-stimulatory role for this ligand in human breast and ovarian epithelial cells. We find no evidence that heregulin has any growth-inhibitory effects in human epithelial cells. We also quantitated the amount of each member of the type I receptor tyrosine kinase family (RTK I, i.e. HER-1, HER-2, HER-3 and HER-4) in the cell lines employed and correlated this to their respective heregulin responses. These data demonstrate that HER-2/neu overexpression itself affects the expression of other RTK I members and that cells expressing the highest levels of HER-2/neu have the greatest response to HRG.
Oncogene 11/1999; 18(44):6050-62. · 6.37 Impact Factor
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ABSTRACT: Amplification and resulting overexpression of the HER-2/ neu proto-oncogene is found in approximately 30% of human breast and 20% of human ovarian cancers. To better understand the molecular events associated with overexpression of this gene in human breast cancer cells, differential hybridization was used to identify genes whose expression levels are altered in cells overexpressing this receptor. Of 16 000 clones screened from an overexpression cell cDNA library, a total of 19 non-redundant clones were isolated including seven whose expression decreases (C clones) and 12 which increase (H clones) in association with HER-2/ neu overexpression. Of these, five C clones and 11 H clones have been confirmed to be differentially expressed by northern blot analysis. This group includes nine genes of known function, three previously sequenced genes of relatively uncharacterized function and four novel genes without a match in GenBank. Examination of the previously characterized genes indicates that they represent sequences known to be frequently associated with the malignant phenotype, suggesting that the subtraction cloning strategy used identified appropriate target genes. In addition, differential expression of 12 of 16 (75%) cDNAs identified in the breast cancer cell lines are also seen in HER-2/ neu -overexpressing ovarian cancer cells, indicating that they represent generic associations with HER-2/ neu overexpression. Finally, up-regulation of two of the identified cDNAs, one novel and one identified but as yet uncharacterized gene, was confirmed in human breast cancer specimens in association with HER-2/ neu overexpression. Further characterization of these genes may yield insight into the fundamental biology and pathogenetic effects of HER-2/ neu overexpression in human breast and ovarian cancer cells.
Nucleic Acids Research 11/1999; 27(20):4008-17. · 8.03 Impact Factor
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M A Cobleigh,
C L Vogel,
D Tripathy,
N J Robert,
S Scholl,
L Fehrenbacher,
J M Wolter,
V Paton,
S Shak,
G Lieberman, D J Slamon
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ABSTRACT: Overexpression of the HER2 protein occurs in 25% to 30% of human breast cancers and leads to a particularly aggressive form of the disease. Efficacy and safety of recombinant humanized anti-HER2 monoclonal antibody as a single agent was evaluated in women with HER2-overexpressing metastatic breast cancer that had progressed after chemotherapy for metastatic disease.
Two hundred twenty-two women, with HER2-overexpressing metastatic breast cancer that had progressed after one or two chemotherapy regimens, were enrolled. Patients received a loading dose of 4 mg/kg intravenously, followed by a 2-mg/kg maintenance dose at weekly intervals.
Study patients had advanced metastatic disease and had received extensive prior therapy. A blinded, independent response evaluation committee identified eight complete and 26 partial responses, for an objective response rate of 15% in the intent-to-treat population (95% confidence interval, 11% to 21%). The median duration of response was 9.1 months; the median duration of survival was 13 months. The most common adverse events, which occurred in approximately 40% of patients, were infusion-associated fever and/or chills that usually occurred only during the first infusion, and were of mild to moderate severity. These symptoms were treated successfully with acetaminophen and/or diphenhydramine. The most clinically significant adverse event was cardiac dysfunction, which occurred in 4.7% of patients. Only 1% of patients discontinued the study because of treatment-related adverse events.
Recombinant humanized anti-HER2 monoclonal antibody, administered as a single agent, produces durable objective responses and is well tolerated by women with HER2-overexpressing metastatic breast cancer that has progressed after chemotherapy for metastatic disease. Side effects that are commonly observed with chemotherapy, such as alopecia, mucositis, and neutropenia, are rarely seen.
Journal of Clinical Oncology 10/1999; 17(9):2639-48. · 18.37 Impact Factor
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ABSTRACT: The anti-HER-2/neu antibody trastuzumab (Herceptin; Genentech, San Francisco, CA) interferes with DNA repair induced by cisplatin and, as a result, promotes cytotoxicity in HER-2/neu-overexpressing tumor target cells in a synergistic fashion. This effect of trastuzumab, termed receptor-enhanced chemosensitivity, is specific for HER-2/neu-overexpressing cells, having no effect on cells without overexpression. Based on these findings, we conducted phase I and II clinical trials of trastuzumab plus cisplatin to determine the toxicity, pharmacokinetics, response rate, and response duration of this combination in patients with HER-2/neu-overexpressing metastatic breast cancer who had demonstrated disease progression (chemoresistance) while on active chemotherapy just prior to study entry. In phase I, four of 15 patients had objective clinical responses, including one complete response of several years' duration. Of 37 assessable patients enrolled in phase II, nine (24.3%) had objective clinical responses and an additional nine had minor responses or stable disease. The median time to progression among the responders was 8.4 months. The toxicity profile reflected that expected from cisplatin alone, with no apparent increase in toxicity caused by the addition of trastuzumab. Moreover, the pharmacokinetics of trastuzumab were unaltered by coadministration of cisplatin. We conclude that the combination of trastuzumab and cisplatin results in response rates higher than that reported for either single agent alone. Such receptor-enhanced chemosensitivity offers a new approach to target overexpressed growth factor receptors in a variety of cancers, which will lead to new, biologically based therapeutic strategies for clinical intervention.
Seminars in Oncology 09/1999; 26(4 Suppl 12):89-95. · 3.50 Impact Factor
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ABSTRACT: The management of human breast cancer frequently includes radiation therapy as an important intervention, and improvement in the clinical efficacy of radiation is desirable. Overexpression of the HER-2 growth factor receptor occurs in 25-30% of human breast cancers and correlates with poor clinical outcome, including earlier local relapse following conservative surgery accompanied by radiation therapy. In breast cancer cells with overexpression of HER-2 receptor, recombinant humanized monoclonal antibodies (rhuMAbs) to HER-2 receptors (rhuMAb HER-2) decrease cell proliferation in vitro and reduce tumor formation in nude mice. Therapy with rhuMAb HER-2 enhances tumor sensitivity to radiation at doses of 1-5 Gy, exceeding remission rates obtained with radiation alone. This benefit is specific to cells with HER-2 overexpression and does not occur in cells without overexpression. Treatment of cells with radiation (2-4 Gy) alone provokes a marked increase in unscheduled DNA synthesis, a measure of DNA repair, but HER-2-overexpressing cells treated with a combination of rhuMAb HER-2 and radiation demonstrate a decrease of unscheduled DNA synthesis to 25-44% of controls. Using an alternate test of DNA repair, i.e., radiation-damaged or undamaged reporter DNA, we introduced a cytomegalovirus-driven beta3-galactosidase into HER-2-overexpressing breast cancer cells that had been treated with rhuMAb HER-2 or control. At 24 h posttransfection, the extent of repair assayed by measuring reporter DNA expression was high after exposure to radiation alone but significantly lower in cells treated with combined radiation and rhuMAb HER-2 therapy. To further characterize effects of rhuMAb HER-2 and the combination of antibody and radiation on cell growth, analyses of cell cycle phase distribution were performed. Antibody reduces the fraction of HER-2-overexpressing breast cancer cells in S phase at 24 and 48 h. Radiation treatment is also known to promote cell cycle arrest, predominantly at G1, with low S-phase fraction at 24 and 48 h. In the presence of rhuMAb HER-2, radiation elicits a similar reduction in S phase at 24 h, but a significant reversal of this arrest appears to begin 48 h postradiation exposure. The level of S-phase fraction at 48 h is significantly greater than that found at 24 h with the combined antibody-radiation therapy, suggesting that early escape from cell cycle arrest in the presence of antireceptor antibody may not allow sufficient time for completion of DNA repair in HER-2-overexpressing cells. Because it is well known that failure of adequate p21WAF1 induction after DNA damage is associated with failure of cell cycle arrest, we also assessed the activity of this critical mediator of the cellular response to DNA damage. The results show induction of p21WAF1 transcripts and protein product at 6, 12, and 24 h after radiation treatment; however, increased levels of p21WAF1 transcript and protein are not sustained in HER-2-overexpressing cells exposed to radiation in the presence of rhuMAb HER-2. Although transcript and protein levels increase at 6-12 h, they are both diminished by 24 h. Levels of p21WAF1 transcript and protein at 24 h are significantly lower than in cells treated by radiation without antibody. A reduction in the basal level of p21WAF1 transcript also occurred after 12-24 h exposure to antibody alone. The effect of HER-2 antibody may be related to tyrosine phosphorylation of p21WAF1 protein. Tyrosine phosphorylation of p21WAF1 is increased after treatment with radiation alone, but phosphorylation is blocked by combined treatment with antireceptor antibody and radiation. This dysregulation of p21WAF1 in HER-2-overexpressing breast cells after treatment with rhuMAb HER-2 and radiation appears to be independent of p53 expression levels but does correlate with reduced levels of mdm2 protein. (ABSTRACT TRUNCATED)
Cancer Research 04/1999; 59(6):1347-55. · 7.86 Impact Factor
