Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The androgen receptor (AR) is the most widely expressed steroid hormone receptor in human breast cancers and androgens including 5alpha-dihydrotestosterone are potent inhibitors of breast cancer cell proliferation. The extracellular signal-regulated mitogen activated protein kinase (ERK/MAPK) pathway is hyperactivated in a proportion of breast tumors and can interact with steroid hormone receptor signaling by altering receptor phosphorylation, turnover, ligand, and cofactor interactions. To examine the effects of ERK/ MAPK hyperactivity on AR levels, MCF-7 cells were stably transfected with a plasmid encoding a constitutively active MEK1 protein to create MCF-7-DeltaMEK1 cells. Treatment of MCF-7-DeltaMEK1 with androgens caused a transient increase in AR protein levels, similar to that observed in untransfected MCF-7 cells treated with androgens. Androgens also inhibited the proliferation of MCF-7-DeltaMEK1 cells by 50-60% following 8 days of treatment in association with increased accumulation of cells in the G1 phase of the cell cycle. These results indicate that although ERK/MAPK hyperactivation in breast cancer cells is associated with reduced estrogen receptor (ERalpha) levels and antiestrogen resistance, AR levels are maintained and breast cancer cells remain susceptible to the growth inhibitory effects of androgens.
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PMID:ERK/MAPK regulation of the androgen responsiveness of breast cancer cells. 1849 66

Many hormone receptor-positive tumors show primary or acquired resistance, possibly because of a crosstalk with other growth factor-related transduction pathways (mainly epidermal growth factor receptor family related). The LETLOB study is a European multicenter, placebo-controlled, randomized phase II trial in postmenopausal patients with hormone-sensitive, HER2-negative, stage II-IIIA (T > 2 cm, N0-1, M0) breast cancer, in which letrozole or the combination of letrozole plus lapatinib will be administered for 6 months before surgery. Clinical endpoints (primary [ultrasonographic objective response], secondary [rate of pathologic complete response and of conservative surgery, safety, and time to treatment failure], and biologic [inhibition of intermediate and final biomarkers of the proliferative and apoptosis pathways and gene profile correlation with response]) will be evaluated.
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PMID:Letrozole versus letrozole plus Lapatinib (GW572016) in hormone-sensitive, HER2-negative operable breast cancer: a double-blind, randomized, phase II study with biomarker evaluation (EGF109077-LAP107692/LETLOB). 1850 Oct 66

The aim of this study was to assess the characteristics of breast cancer patients with central nervous system (CNS) metastases and factors associated with survival after development of CNS metastasis. One-hundred-forty-four patients with brain metastases were retrospectively analyzed. Median age at the time of brain metastasis diagnosis was 48.9. Median time between initial diagnosis and development of brain metastasis was 36 months. Fourteen cases had leptomeningeal involvement. Twenty-two patients (15.3%) had single metastasis. Ten percent of the patients had surgery, 94% had radiotherapy and 63% had chemotherapy. Median survival after development of brain metastasis was 7.4 months. Survival of patients with single metastasis was significantly longer than those with multiple metastases (33.5 vs. 6.5 months, p = 0.0006). Survival of patients who received chemotherapy was significantly longer than those who received radiotherapy alone (9.9 vs. 2 months, p < 0.0001). In multivariate Cox regression analyses, presence of single metastasis and application of chemotherapy were the only significant factors associated with better survival (p = 0.047 and p < 0.0001, respectively). Age at initial diagnosis or at the time of brain metastasis, time from initial diagnosis to development of brain metastasis, menopausal status, tumor stage, grade, hormone receptor or HER2 status individually were not associated with survival. In this study, survival after the diagnosis of CNS metastases appeared to be affected by patient characteristics rather than biologic characteristics of the tumor. This is probably secondary to the lack of effective treatment options in these patients and overall poor prognosis.
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PMID:Characteristics of breast cancer patients with central nervous system metastases: a single-center experience. 1850 4

Breast cancer is the second leading cause of cancer-related death in women in the United States, and for nearly all with metastatic disease at presentation or relapse it will be incurable. The goals of therapy are to optimize quality of life and, if possible, prolong time to progression of disease and death. For a select group of patients an aggressive surgical approach may be considered. Initial palliation with endocrine therapy should be the primary consideration for patients with metastatic hormone receptor-positive tumors. Cytotoxic chemotherapy is appropriate for those with hormone-refractory disease, rapidly progressive visceral disease, or early relapse after adjuvant therapy. If a tumor overexpresses HER2, targeted treatment with trastuzumab (Herceptin) or lapatinib (Tykerb) is possible. Consequently, accurate determination of the status of these predictive markers in tissue (possibly from a recurrence site) is key. Other novel agents are adding to the wide choices of standard chemotherapies already available. This review offers an approach to the selection of individualized and rational therapies for patients with metastatic breast cancer.
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PMID:Therapeutic options in the management of metastatic breast cancer. 1856 51

Gene expression studies have identified a basal phenotype of breast cancer; these are hormone receptor and HER2-negative cancers with poor prognosis. High levels of cyclin E and Skp2, and low levels of p27 have previously been individually associated with both basal-like breast cancer and a poor outcome after diagnosis. The goal of this study was to first confirm the prognostic value of these biomolecular markers using a breast cancer tissue microarray. Second, we also test the hypothesis that the combined phenotype of high cyclin E, low p27, and high Skp2 would be a strong predictor of outcome and would be closely associated with the basal phenotype of breast cancer. Our cohort consisted of 438 cases of breast cancer and the median follow-up was 15.4 years. The tissue microarray was constructed from archival tumor blocks and we used commercially available antibodies for biomarker immunostaining. Cyclin E was positive in 46% of cases, p27 was negative in 62%, and Skp2 was positive in 35%. We found cyclin E and Skp2 to be prognostic for breast cancer-specific survival in univariate analyses, but p27 was not prognostic. The strongest predictor of outcome was the combination of cyclin E positive and Skp2 positive (difference in survival of 19% at 10 years, P = .0009). This combination was present in 78 (27%) of 288 cases for which data on both biomarkers were available. This combination was also highly associated with young age at diagnosis, grade 3 tumors, ER-negative status, HER2-negative status, and the basal biomarkers epidermal growth factor receptor and cytokeratin 5/6. However, in a multivariate model including standard clinicopathologic variables, this combination was not found to have independent prognostic significance. In conclusion, the combination of high cyclin E and Skp2 expression predicts for poor prognosis in breast cancer in univariate analysis only, it is associated with high risk features, and it is associated with the basal phenotype.
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PMID:The combination of high cyclin E and Skp2 expression in breast cancer is associated with a poor prognosis and the basal phenotype. 1862 Jul 30

Thyroid hormone receptor alpha1 (TRalpha1) is predominantly expressed in the myocardium but its biological function under physiological or pathological conditions remains largely unknown. The present study investigated possible interactions between alpha1 adrenergic and thyroid hormone signaling at the level of TRalpha1, potential underlying mechanisms and physiological consequences, as well as the role of TRalpha1 in cell differentiation. This may be of physiological relevance since both thyroid hormone and adrenergic signalling are implicated in the pathophysiology of cardiac remodelling. Neonatal cardiomyocytes obtained from newborn rats (2-3 days) were exposed to phenylephrine (PE, an alpha1 adrenergic agonist) for 5 days, in the absence or excess of T3 in the culture medium. PE, in the absence of T3, resulted in 5.0 fold increase in TRalpha1 expression in nucleus and 2.0 fold decrease in TRalpha1 expression in cytosol, P<0.05. As a result, a fetal pattern of myosin isoform expression with marked expression of beta-MHC was observed in PE treated vs the untreated cells, P<0.05. PD98059 (an ERK signalling inhibitor) abrogated this response. In the presence of T3 in the culture medium, TRalpha1 expression was increased 1.6 fold in nucleus and 2.0 fold in cytosol in PE-T3 vs PE treated cells, P<0.05, and the fetal pattern of myosin isoform expression was prevented. Parallel studies with H9c2 myoblasts showed that reduction of T3 binding to TRalpha1 receptor delayed cardiac myoblasts differentiation without affecting proliferation. In conclusion, in neonatal cardiomyocytes, nuclear TRalpha1 is overexpressed after prolonged activation of the alpha1- adrenergic signalling by PE. This response seems to be an ERK kinase dependent process. Over-expression of TRalpha1 may lead to fetal cardiac phenotype in the absence of thyroid hormone availability. Furthermore, TRalpha1 seems to be critical in cardiac myoblast differentiation.
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PMID:Thyroid hormone receptor alpha 1: a switch to cardiac cell "metamorphosis"? 1862 44

A 53-year-old woman with locally advanced breast cancer exhibiting skin edema and axial lymph-node swelling was treated by pre-operative systemic therapy. A core needle biopsy revealed the tumor to be a solid-tubular carcinoma which was hormone receptor-negative and HER2-positive. Six courses of an anthracycline-based regimen (5-fluorouracil, epirubicin, cyclophosphamide; FEC) and 6 weekly courses of paclitaxel concomitant with trastuzumab were sequentially administered. After those treatments, the tumor presented as clinically CR. An incisional biopsy of the left breast showed that the tumor was completely eliminated, with ductal carcinoma absent upon pathological examination.
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PMID:[A case of locally advanced breast cancer successfully treated by pre-operative systemic therapy using paclitaxel and trastuzumab]. 1863 28

As reflected in its varied clinical behavior, appearances under the light microscope, and differential patterns of gene expression, metastatic breast cancer (MBC) is a heterogeneous disease. Systemic treatment decisions are guided by specific tumor characteristics and individual patient factors. For patients with hormone receptor (HR)-negative MBC and for those whose HR-positive disease has become refractory to hormonal therapies, cytotoxic chemotherapy has been the mainstay of systemic treatment. For hormone-insensitive, HER2-positive MBCs, the addition of trastuzumab to chemotherapy has resulted in improved outcomes. Hormone-insensitive MBC lacking HER2 overexpression includes the subset of patients with estrogen receptor/ progesterone receptor/HER2-negative (so-called triple-negative) disease, which represents a significant minority of all breast cancers. Therapeutic options for such patients are limited by the lack of specific targeted approaches, and this heterogeneous group will be considered collectively as well as separately in this overview of existing and emerging treatment strategies. Conventional cytotoxic chemotherapy, alone or in combination, has been the standard first-line treatment for patients with MBC not amenable to antiestrogen or trastuzumab therapy. The recent evaluation of new targeted therapies in combination with cytotoxic agents has created a new type of combination regimen. Agents targeting angiogenesis, the epidermal growth factor receptor, and various signal transduction pathways have been combined with chemotherapy and possess biologic activity in MBC. As these combinations are being investigated, parallel correlative studies aimed at enriching the population who will benefit most are under way.
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PMID:Beyond cytotoxic chemotherapy for the first-line treatment of HER2-negative, hormone-insensitive metastatic breast cancer: current status and future opportunities. 1865 Jan 51

Although the clinical relevance of molecular subtypes of breast cancer has been documented, little is known about risk factors for different tumor subtypes, especially the HER2-overexpressing and the triple-negative subtypes that have poor prognoses. Obesity may be differentially related to the risk of different subtypes given the various potential mechanisms underlying its association with breast cancer. We pooled two population-based case-control studies of postmenopausal breast cancer for an analysis, including 1,447 controls and 1,008 luminal (hormone receptor positive), 39 HER2-overexpressing (hormone receptor negative, HER2 positive), and 77 triple-negative (hormone receptor and HER2 negative) cases. Associations between anthropometric factors and the risk of different breast cancer subtypes were evaluated using polytomous logistic regression. Among women not currently using menopausal hormone therapy, body mass index (BMI) and weight were associated with the risk of luminal tumors [odds ratio (OR) comparing highest versus lowest quartiles, 1.7; 95% confidence interval (95% CI), 1.2-2.4 and OR, 1.7; 95% CI, 1.2-2.4, respectively] and suggestively associated with risk of triple-negative tumors (OR, 2.7; 95% CI, 1.0-7.5 and OR, 5.1; 95% CI, 1.1-23.0, respectively). Neither BMI nor weight was associated with the risk of any tumor subtype among hormone therapy users. The positive relationship between BMI and luminal tumors among postmenopausal women not using hormone therapy is well characterized in the literature. Although our sample size was limited, body size may also be related to the risk of postmenopausal triple-negative breast cancer among nonusers of hormone therapy. Given the expanding obesity epidemic, the widespread cessation of hormone therapy use, and the poor prognosis of triple-negative tumors, this novel finding merits confirmation.
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PMID:Body size and risk of luminal, HER2-overexpressing, and triple-negative breast cancer in postmenopausal women. 1866 48

Phosphatidylinositol 3-kinase (PI3K)/AKT pathway aberrations are common in cancer. By applying mass spectroscopy-based sequencing and reverse-phase protein arrays to 547 human breast cancers and 41 cell lines, we determined the subtype specificity and signaling effects of PIK3CA, AKT, and PTEN mutations and the effects of PIK3CA mutations on responsiveness to PI3K inhibition in vitro and on outcome after adjuvant tamoxifen. PIK3CA mutations were more common in hormone receptor-positive (34.5%) and HER2-positive (22.7%) than in basal-like tumors (8.3%). AKT1 (1.4%) and PTEN (2.3%) mutations were restricted to hormone receptor-positive cancers. Unlike AKT1 mutations that were absent from cell lines, PIK3CA (39%) and PTEN (20%) mutations were more common in cell lines than tumors, suggesting a selection for these but not AKT1 mutations during adaptation to culture. PIK3CA mutations did not have a significant effect on outcome after adjuvant tamoxifen therapy in 157 hormone receptor-positive breast cancer patients. PIK3CA mutations, in comparison with PTEN loss and AKT1 mutations, were associated with significantly less and inconsistent activation of AKT and of downstream PI3K/AKT signaling in tumors and cell lines. PTEN loss and PIK3CA mutation were frequently concordant, suggesting different contributions to pathophysiology. PTEN loss rendered cells significantly more sensitive to growth inhibition by the PI3K inhibitor LY294002 than did PIK3CA mutations. Thus, PI3K pathway aberrations likely play a distinct role in the pathogenesis of different breast cancer subtypes. The specific aberration present may have implications for the selection of PI3K-targeted therapies in hormone receptor-positive breast cancer.
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PMID:An integrative genomic and proteomic analysis of PIK3CA, PTEN, and AKT mutations in breast cancer. 1867 30


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