Aromatase inhibitors (AI) are currently the first line therapy for estrogen receptor (ER)-positive postmenopausal women. De novo AI resistance is when a patient intrinsically does not respond to an AI therapy as well as other targeted endocrine therapy. To characterize this type of resistance and to examine potential therapies for treatment, we have generated two cell models for de novo resistance. These models derive from MCF-7 cells that stably overexpress aromatase and Akt (AKT-aro) or HER2 (HER2-aro). Evaluation of these cell lines revealed that the activities of aromatase and ER were inhibited by AI and ICI 187280 (ICI) treatment, respectively; however, cell growth was resistant to therapy. Proliferation in the presence of the pure anti-estrogen ICI, indicates that these cells do not require ER for cell growth and distinguishes these cells from the acquired AI resistant cells. We further determined that the HSP90 inhibitor 17-DMAG suppressed the growth of the AI-resistant cell lines studied. Our analysis revealed 17-DMAG-mediated decreased expression of growth promoting signaling proteins. It was found that de novo AI resistant AKT-aro and HER2-aro cells could not be resensitized to letrozole or ICI by treatment with 17-DMAG. In summary, we have generated two cell lines which display the characteristics of de novo AI resistance. Together, these data indicate the possibility that HSP90 inhibitors may be a viable therapy for endocrine therapy resistance although additional clinical evaluation is needed.
HSP90 inhibitors; Breast cancer; De novo aromatase inhibitor resistance
Only 3% of women with breast cancer participate in cancer clinical trials nationwide. The lack of awareness about clinical trials is a significant barrier towards clinical trials participation. A study was conducted at a large urban Comprehensive Cancer Center to test (1) the effectiveness of an 18-min educational video on improving attitudes toward clinical trials and trials enrollment among new breast cancer patients seen at the Karmanos Cancer Institute, and (2) to assess racial differences in attitudes regarding clinical trials. Participants were randomized to either the educational intervention prior to their first oncology clinic appointment or to standard care. A baseline and 2-week post-intervention survey to assess attitudes toward clinical trials participation was completed by participants. Of 218 subjects recruited, 196 (55% white vs. 45% African American (AA)) eligible patients were included in the analysis. A small increase in therapeutic clinical trial enrollment was observed in the intervention arm but was not statistically significant (10.4% vs. 6.1%; P = 0.277). The intervention also did not result in a clear improvement in patients’ attitudes toward clinical trials at posttest. However, a lower enrollment rate for the AA women was noted after adjusting for stage (OR = 0.282, P = 0.049). Significantly more negative scores were noted in 3 out of the 5 baseline attitudinal scales for AA women. The educational video did not significantly increase enrollment in breast cancer clinical trials. The findings that AA women had significantly more negative attitudes toward clinical trials than white women may partially explain the racial disparity in enrollment. An educational video remains a simple and cost-effective way to educate patients. Future studies should focus on designing a new educational video to specifically target cultural and attitudinal barriers in the AA population to more effectively change attitudes and increase trial enrollment.
Clinical trials enrollment; Breast cancer; Educational video; Attitudes regarding clinical trials; Racial disparity
Inflammatory Breast Carcinoma (IBC), the most aggressive type of breast tumor with unique clinicopathological presentation, is hypothesized to have distinct etiology with a socioeconomic status (SES) component. Using the Surveillance, Epidemiology and End Results (SEER) Program data for 2004–2007, we compare incidence rates of IBC to non-inflammatory locally advanced breast cancer (LABC) among racial/ethnic groups with different SES. The analysis includes women 20–84 years of age. To examine evidence for the distinct etiology of IBC, we analyzed age-distribution patterns of IBC and non-inflammatory LABC, using a mathematical carcinogenesis model. Based on the Collaborative Staging Extension codes, 2,942 incident IBC cases (codes 71 and 73) and 5,721 non-inflammatory LABC cases (codes 40–62) were identified during the four-year study period. Age-adjusted rates of IBC among non-Hispanic White and Hispanic women were similar (2.5/100,000 in both groups). Similar rates were also found in non-inflammatory LABC in these two groups (4.8/100,000 and 4.2/100,000, respectively). In African-American women, the IBC (3.91/100,000) and non-inflammatory LABC (8.47/100,000) rates were greater compared with other ethnic/racial sub-groups. However, the ratio of rates of IBC/non-inflammatory LABC was similar among all the racial/ethnic groups, suggesting that African-American women are susceptible to aggressive breast tumors in general but not specifically to IBC. The mathematical model successfully predicted the observed age-specific rates of both examined breast tumors and revealed distinct patterns. IBC rates increased until age 65 and then slightly decreased, whereas non-inflammatory LABC rates steadily increased throughout the entire age interval. The number of critical transition carcinogenesis stages (m-stages) predicted by the model were 6.3 and 8.5 for IBC and non-inflammatory LABC, respectively, supporting different etiologies of these breast tumors.
Epidemiology; Inflammatory breast cancer; Etiology
Body composition changes cannot be precisely captured using body weight or body mass index measures. Therefore, the primary purpose of this review was to characterize the patterns of body composition change in females treated for breast cancer including only studies that utilize imaging technologies to quantify adipose tissue and lean body mass (LBM). We reviewed PubMed for studies published between 1971–2012 involving females diagnosed with breast cancer where computed axial tomography (CAT), dual energy x-ray absorptiometry (DXA) or magnetic resonance imaging (MRI) were employed for body composition assessment. Of the initial 440 studies, 106 papers were evaluated and 36 papers met all eligibility criteria (15 observational and 21 intervention trials). Results of these studies revealed that body weight did not consistently increase. Importantly, studies also showed that body weight did not accurately depict changes in lean or adipose tissues. Further findings included that sarcopenic obesity as a consequence of breast cancer treatment was not definitive, as menopausal status may be a substantial moderator of body composition. Overall, the behavioral interventions did not exhibit consistent or profound effects on body composition outcomes; approximately half showed favorable influence on adiposity while the effects on LBM were not apparent. The use of tamoxifen had a clear negative impact on body composition. The majority of studies were conducted in predominantly white survivors, highlighting the need for trials in minority populations. Collectively, these studies were limited by age, race and/or menopause status matched control groups, overall size and statistical power. Very few studies simultaneously collected diet and exercise data- two potential factors that impact body composition. Future breast cancer trials should prioritize precise body composition methodologies to elucidate how these changes impact recurrence, prognosis and mortality, and to provide clinicians with appropriate advice regarding lifestyle recommendations in this growing sector of the population.
breast cancer; body composition; adiposity; lean body mass; breast cancer treatment; imaging
The purpose of this study was to evaluate the preliminary efficacy and satisfaction/acceptability of training in memory or speed of processing versus wait-list control for improving cognitive function in breast cancer survivors. 82 breast cancer survivors completed a three-group randomized, controlled trial. Primary outcomes were objective neuropsychological tests of memory and speed of processing. Secondary outcomes were perceived cognitive functioning, symptom distress (mood disturbance, anxiety, and fatigue), quality of life, and intervention satisfaction/acceptability. Data were collected at baseline, post-intervention, and 2-month follow-up. Using repeated-measures mixed-linear ANCOVA models, each intervention was compared to wait-list control while adjusting for age, education, and baseline measures. The effect sizes for differences in means and the reliable improvement percentage were reported. The results show that domain-specific effects were seen for both interventions: memory training improved memory performance at 2-month follow-up (p = 0.036, d = 0.59); speed of processing training improved processing speed post-intervention (p = 0.040, d = 0.55) and 2-month follow-up (p = 0.016; d = 0.67). Transfer effects to non-trained domains were seen for speed of processing training with improved memory post-intervention (p = 0.007, d = 0.75) and 2-month follow-up (p = 0.004, d = 0.82). Both interventions were associated with improvements in perceived cognitive functioning, symptom distress, and quality of life. Ratings of satisfaction/acceptability were high for both interventions. It was concluded that while both interventions appeared promising, speed of processing training resulted in immediate and durable improvements in objective measures of processing speed and verbal memory. Speed of processing training may have broader benefits in this clinical population.
Memory; Speed of processing; Breast cancer survivors; Symptom distress; Quality of life
Travel time has been shown to influence some aspects of cancer characteristics at diagnosis and care for women with breast cancer, but important gaps remain in our understanding of its impact. We examined the influence of travel time to the nearest radiology facility on breast cancer characteristics, treatment, and surveillance for women with early-stage invasive breast cancer. We included 1,012 women with invasive breast cancer (stages I and II) who had access to care within an integrated health care delivery system in western Washington State. The travel times to the nearest radiology facility were calculated for all the U.S. Census blocks within the study area and assigned to women based on residence at diagnosis. We collected cancer characteristics, primary and adjuvant therapies, and surveillance mammography for at least 2.5 years post diagnosis and used multivariable analyses to test the associations of travel time. The majority of women (68.6%) lived within 20 min of the nearest radiology facility, had stage I disease (72.7%), received breast conserving therapy (68.7%), and had annual surveillance mammography the first 2 years after treatment (73.7%). The travel time was not significantly associated with the stage or surveillance mammography after adjusting for covariates. Primary therapy was significantly related to travel time, with greater travel time (>30 min vs. ≤ 10 min) associated with a higher likelihood of mastectomy compared to breast conserving surgery (RR = 1.53; 95% CI, 1.16–2.01). The travel time was not associated with the stage at diagnosis or surveillance mammography receipt. The travel time does seem to influence the type of primary therapy among women with breast cancer, suggesting that women may prefer low frequency services, such as mastectomy, if geographic access to a radiology facility is limited.
Mammography; Travel time; Integrated delivery system; Breast carcinoma; Breast cancer therapy
Feasibility and reproducibility of microarray biomarkers in clinical settings are doubted because of reliance on fresh frozen tissue. We sought to develop and test a paradigm of frozen tissue collection from early breast tumors to enable use of microarray in oncology practice.
Frozen core needle biopsies (CNBx) were collected from 150 clinical stage I patients during image-guided diagnostic biopsy and/or surgery. Histology and tumor content from frozen cores were compared to diagnostic specimens. Twenty eight patients had microarray analysis to examine accuracy and reproducibility of predictive gene signatures developed for estrogen receptor (ER) and HER2.
One hundred twenty seven (85%) of 150 patients had at least one frozen core containing cancer suitable for microarray analysis. Larger tumor size, ex vivo biopsy, and use of a new specimen device increased the likelihood of obtaining representative specimens. Sufficient quality RNA was obtained from 90% of tumor cores. Microarray signatures predictive ER and HER2 expression were developed in a training sets of up to 356 surgical samples and were applied to microarray data obtained from core samples collected in clinical settings. In these samples, a sensitivity / specificity of 94% / 100% and 82% / 72% for predicting ER and HER2, respectively was achieved. Predictions were reproducible in 83–100% of paired diagnostic and surgical samples.
Frozen CNBx can be readily obtained from most breast cancers without interfering with pathologic evaluation. Collection of tumor tissue at diagnostic biopsy and/or at surgery from lumpectomy specimens using image guidance resulted in sufficient samples for array analysis from over 90% of patients. Sampling of breast cancer for microarray data is reproducible and feasible in clinical settings and can yield signatures predictive of multiple breast cancer phenotypes.
The aim of this study was determine the effectiveness of a mindfulness-based stress-reduction (MBSR) program on quality of life (QOL) and psychosocial outcomes in women with early-stage breast cancer, using a three-arm randomized controlled clinical trial (RCT). This RCT consisting of 172 women, aged 20–65 with stage I or II breast cancer consisted of the 8-week MBSR, which was compared to a nutrition education program (NEP) and usual supportive care (UC). Follow-up was performed at three post-intervention points: 4 months, 1, and 2 years. Standardized, validated self-administered questionnaires were adopted to assess psychosocial variables. Statistical analysis included descriptive and regression analyses incorporating both intention-to-treat and post hoc multivariable approaches of the 163 women with complete data at baseline, those who were randomized to MBSR experienced a significant improvement in the primary measures of QOL and coping outcomes compared to the NEP, UC, or both, including the spirituality subscale of the FACT-B as well as dealing with illness scale increases in active behavioral coping and active cognitive coping. Secondary outcome improvements resulting in significant between-group contrasts favoring the MBSR group at 4 months included meaningfulness, depression, paranoid ideation, hostility, anxiety, unhappiness, and emotional control. Results tended to decline at 12 months and even more at 24 months, though at all times, they were as robust in women with lower expectation of effect as in those with higher expectation. The MBSR intervention appears to benefit psychosocial adjustment in cancer patients, over and above the effects of usual care or a credible control condition. The universality of effects across levels of expectation indicates a potential to utilize this stress reduction approach as complementary therapy in oncologic practice.
Mindfulness-based stress reduction program; Quality of life; Psychosocial factors; Expectancy; Breast cancer psychosocial intervention
The genetic component of breast cancer predisposition remains largely unexplained. Candidate-gene case-control resequencing has identified predisposition genes characterised by rare, protein truncating mutations that confer moderate risks of disease. In theory, exome sequencing should yield additional genes of this class. Here, we explore the feasibility and design considerations of this approach.
We performed exome sequencing in 50 individuals with familial breast cancer, applying frequency and protein function filters to identify variants most likely to be pathogenic. We identified 867,378 variants that passed the call quality filters of which 1,296 variants passed the frequency and protein truncation filters. The median number of validated, rare, protein truncating variants (PTVs) was 10 in individuals with, and without, mutations in known genes. The functional candidacy of mutated genes was similar in both groups. Without prior knowledge, the known genes would not have been recognisable as breast cancer predisposition genes. Everyone carries multiple rare mutations that are plausibly related to disease. Exome sequencing in common conditions will therefore require intelligent sample and variant prioritisation strategies in large case-control studies to deliver robust genetic evidence of disease association.
breast cancer predisposition; exome sequencing; common disease genetics; missing heritability
Previous studies suggest that melatonin may act on cancer growth through a variety of mechanisms, most notably by direct anti-proliferative effects on breast cancer cells and via interactions with the estrogen pathway. Three genes are largely responsible for mediating the downstream effects of melatonin: melatonin receptors 1a and 1b (MTNR1a and MTNR1b), and Arylalkylamine N-acetyltransferase (AANAT). It is hypothesized that genetic variation in these genes may lead to altered protein production or function. To address this question, we conducted a comprehensive evaluation of the association between common single nucleotide polymorphisms (SNPs) in the MTNR1a, MTNR1b, and AANAT genes and breast cancer risk among 2,073 cases and 2,083 controls, using a two-staged analysis of genome-wide association (GWAS) data among women of the Shanghai Breast Cancer Study. Results demonstrate two SNPS were consistently associated with breast cancer risk across both study stages. Compared with MTNR1b rs10765576 major allele carriers (GG or GA), a decreased risk of breast cancer was associated with the AA genotype (OR=0.78, 95% CI=0.62–0.97, p=0.0281). Although no overall association was seen in the combined analysis, the effect of MTNR1a rs7665392 was found to vary by menopausal status (p-value for interaction=0.001). Premenopausal women with the GG genotype were at increased risk for breast cancer as compared to major allele carriers (TT or TG) (OR=1.57, 95% CI=1.07–2.31, p=0.020), while post-menopausal women were at decreased risk (OR=0.58, 95% 0.36–0.95, p=0.030). No significant breast cancer associations were found for variants in AANAT. These results suggest that common genetic variation in the MTNR1a and 1b genes may contribute to breast cancer susceptibility, and that associations may vary by menopausal status. Given that multiple variants in high linkage disequibrium with MTNR1b rs76653292 have been associated with altered function or expression of insulin and glucose family members, further research may focus on clarifying this relationship.
Melatonin; gene; polymorphism; breast cancer; risk
The authors evaluated the prognostic effects of obesity and weight change after breast cancer diagnosis. A total of 5042 breast cancer patients aged 20–75 were identified through the population-based Shanghai Cancer Registry approximately 6 months after cancer diagnosis and recruited into the study between 2002 and 2006. Participants were followed by in-person interviews supplemented by record linkage with the Shanghai Vital Statistics Registry database. Anthropometric measurements were taken and information on sociodemographic, clinical, and lifestyle factors was collected through in-person interviews. During the median follow-up of 46 months, 442 deaths and 534 relapses/breast cancer-specific deaths were documented. Women with body mass index (BMI) ≥30 at diagnosis had higher mortality than women with 18.5≤BMI<25; the multivariate adjusted hazard ratios (HRs) were 1.55 (95% confidence interval (95% CI): 1.10–2.17) for total mortality and 1.44 (95% CI: 1.02–2.03) for relapse/disease-specific mortality. Similar results were found for pre- and post-diagnostic obesity. Women who gained ≥5kg or lost >1kg had higher mortality than those who maintained their weight. No association was observed between waist-to-hip ratio and mortality. Our study suggests that obesity and weight change after diagnosis are inversely associated with breast cancer prognosis. Weight control is important among women with breast cancer.
Body mass index; central obesity; weight change; breast cancer; survival
Previous studies of the association of meat intake and meat-derived mutagen exposure with breast cancer risk have produced inconsistent results. We evaluated this association in a population-based case-control study of incident breast cancer conducted in Nashville, United States, including 2,386 breast cancer cases and 1,703 healthy women controls. Telephone interviews were conducted to obtain information related to meat intake including amount, cooking methods, and doneness levels, as well as other known or hypothesized risk factors for breast cancer. Unconditional logistic regression was used to derive odds ratios (ORs) after adjusting for potential confounders. High intake of red meat was associated with a significantly elevated risk of breast cancer (P-trend <0.001). The association was particularly strong for high intake of well-done red meat (P-trend <0.001), with an adjusted OR of 1.5 (95% CI = 1.3–1.9) for the highest versus the lowest quartile. Associations between red meat and breast cancer risk were slightly stronger for postmenopausal women than for premenopausal women. Meat-derived mutagens such as 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline, were significantly associated with increased breast cancer risk among postmenopausal women only (P-trend = 0.002 and 0.003, respectively). The results from this study provide strong support for the hypotheses that high red meat intake and meat-derived mutagen exposure may be associated with an increase in breast cancer risk.
Dietary factors; nutrition epidemiology; meat-derived mutagens; heterocyclic amines breast cancer
Matrix metalloproteinase-1 (MMP-1) is critical for mediating breast cancer metastasis to bone. We investigated the role of MMP-1 in breast cancer invasion of soft tissues and bone using human MDA MB-231 breast cancer cells stably transfected with shRNAs against MMP-1 and a novel murine model of bone invasion. MMP-1 produced by breast cancer cells with control shRNA facilitated invasion of tumors into soft tissue in vivo, which correlated with enhanced blood vessel formation at the invasive edge, compared to tumors with silenced MMP-1 expression. Tumors expressing MMP-1 were also associated with osteolysis in vivo, whereas tumors with inhibited MMP-1 levels were not. Additionally, tumor-secreted MMP-1 activated bone-resorbing osteoclasts in vitro. Together, these data suggest a mechanism for MMP-1 in the activation of osteoclasts in vivo. We conclude that breast cancer-derived MMP-1 mediates invasion through soft tissues and bone via mechanisms involving matrix degradation, angiogenesis, and osteoclast activation.
Breast cancer; Bone; Invasion; Metastasis; MMP; Murine model
TaqMan Gene Expression assays were used to profile the mRNA expression of estrogen receptor (ERα and ERβ) and estrogen metabolism enzymes including cytosolic sulfotransferases (SULT1E1, SULT1A1, SULT2A1, and SULT2B1), steroid sulfatase (STS), aromatase (CYP19), 17β-hydroxysteroid dehydrogenases (17βHSD1 and 2), CYP1B1, and catechol-O-methyltransferase (COMT) in an MCF10A-derived lineage cell culture model for basal-like human breast cancer progression and in ERα-positive luminal MCF7 breast cancer cells. Low levels of ERα and ERβ mRNA were present in MCF10A-derived cell lines. SULT1E1 mRNA was more abundant in confluent relative to subconfluent MCF10A cells, a non-tumorigenic proliferative breast disease cell line. SULT1E1 was also expressed in preneoplastic MCF10AT1 and MCF10AT1K.cl2 cells, but was markedly repressed in neoplastic MCF10A-derived cell lines as well as in MCF7 cells. Steroid-metabolizing enzymes SULT1A1 and SULT2B1 were only expressed in MCF7 cells. STS and COMT were widely detected across cell lines. Pro-estrogenic 17βHSD1 mRNA was most abundant in neoplastic MCF10CA1a and MCF10DCIS.com cells, while 17βHSD2 mRNA was more prominent in parental MCF10A cells. CYP1B1 mRNA was most abundant in MCF7 cells. Treatment with the histone deacetylase inhibitor trichostatin A (TSA) induced SULT1E1 and CYP19 mRNA but suppressed CYP1B1, STS, COMT, 17βHSD1, and 17βHSD2 mRNA in MCF10A lineage cell lines. In MCF7 cells, TSA treatment suppressed ERα, CYP1B1, STS, COMT, SULT1A1, and SULT2B1 but induced ERβ, CYP19 and SULT2A1 mRNA expression. The results indicate that relative to the MCF7 breast cancer cell line, key determinants of breast estrogen metabolism are differentially regulated in the MCF10A-derived lineage model for breast cancer progression.
Estrogen metabolism; Gene expression; MCF10A lineage; Breast cancer progression; Histone deacetylase inhibition
The malignant biological behavior of breast cancer remains obscure on diagnostic images, although understanding the grade of such malignancy is important for selecting appropriate treatment. Therefore, malignancy grades in operable breast cancer were evaluated using positron emission tomography/computed tomography (PET/CT) in a multicenter setting. We prospectively examined the features and prognosis of 344 patients (mean age ± SD: 58.0 ± 12.5 years) with clinical stages I–III breast cancer, who underwent surgical intervention without induction therapy between January 2006 and December 2011. Maximum standardized uptake values (maxSUV) obtained from whole-body fluorodeoxyglucose-PET/CT immediately before surgery were assessed to predict the malignant aggressiveness of tumors including the recurrence-free survival of the patients. Variations in maxSUV among institutions, which are limitations of PET assessments in multicenter studies, were adjusted using a phantom study. The median follow up period was 52 months. The patients were divided into groups according to cut-off maxSUV (≤3.0 vs. >3.0) values established from receiver operating characteristic analysis of recurrence (area under the curve = 0.713). A higher maxSUV was significantly associated with a higher T-factor (p < 0.0001), N-factor (p = 0.0049), nuclear grade (p < 0.0001), negative for estrogen (p = 0.0309), and progesterone receptors (p = 0.0063), positive for human epidermal growth factor receptor 2 (p = 0.0012), lymph node metastasis (p = 0.0128), and vascular invasion (p = 0.0110). Multivariate analysis using Cox proportional hazard regression model revealed high maxSUV and negative estrogen receptor status as significantly prognostic factors (p = 0.033 and p = 0.004, respectively). This study demonstrated that maxSUV on PET/CT as well as estrogen receptor status is useful to predict malignancy grades and the prognosis of patients with breast cancer.
Breast cancer; PET/CT; maxSUV; Prognosis; Estrogen receptor; Recurrence
Two selective estrogen receptor modulators (SERMs), tamoxifen and raloxifene, have been shown in randomized clinical trials to reduce the risk of developing primary invasive breast cancer (IBC) in high-risk women. In 1998, the U.S. Food and Drug Administration (FDA) used these studies as a basis for approving tamoxifen for primary breast chemoprevention in both premenopausal and postmenopausal women at high risk. In 2007, the FDA approved raloxifene for primary breast cancer chemoprevention for postmenopausal women.
Data from the year 2010 National Health Interview Survey (NHIS) were analyzed to estimate the prevalence of tamoxifen and raloxifene use for chemoprevention of primary breast cancers among U.S. women.
Prevalence of use of chemopreventive agents for primary tumors was 20,598 (95% CI, 518–114,864) for U.S. women aged 35 to 79 for tamoxifen. Prevalence was 96,890 (95% CI, 41,277–192,391) for U.S. women aged 50 to79 for raloxifene.
Use of tamoxifen and raloxifene for prevention of primary breast cancers continues to be low. In 2010, women reporting medication use for breast cancer chemoprevention were primarily using the more recently FDA-approved drug raloxifene. Multiple possible explanations for the low use exist, including lack of awareness and/or concern about side effects among primary care physicians and patients.
Chemoprevention; tamoxifen; raloxifene; breast cancer; side effect
Herein we report our examination of the anti-breast cancer activity of a novel synthetic compound, 7-(benzylamino)-1, 3, 4, 8-tetrahydropyrrolo [4, 3, 2-de]quinolin-8(1H)-one (BA-TPQ). This agent is an analog of a naturally-occurring marine compound, and was found to be the most active out of more than 40 related compounds. We investigated the in vitro activity of BA-TPQ on the survival, proliferation, and apoptosis of breast cancer cells using the MTT and BrdUrd assays, and Annexin/Annexin-PI staining and flow cytometry. The in vivo anti-cancer effects of BA-TPQ were evaluated in xenograft models of breast cancer. Finally, the mechanisms of action of the compound were also assessed by cDNA microarrays, RT-PCR and Western blotting. In a dose-dependent manner, BA-TPQ inhibited cell growth and induced apoptosis and cell cycle arrest in human MCF-7 and MDA-MB-468 breast cancer cells in vitro, and showed in vivo efficacy in mice bearing MCF-7 or MDA-MB-468 xenograft tumors. We demonstrated that BA-TPQ modifies the expression of numerous molecules involved in cell cycle progression and apoptosis. Similar changes in protein expression were observed in vitro and in vivo, as determined by examination of cells and excised xenograft tumors. Our preclinical data indicate that BA-TPQ is a potential therapeutic agent for breast cancer that has multiple hormone-, Her2- and p53-independent mechanisms of action, providing a basis for further development of the compound as a novel anticancer agent.
Breast cancer; Chemotherapy; Apoptosis; Cell cycle progression
Breast Cancer; Mammography; Body Mass Index; Adipose Tissue; Risk
Breast cancer is a burden for American Indian (AI) women who have younger age at diagnosis and higher stage of disease. Rural areas also have had less access to screening mammography. An Indian Health Service Mobile Women’s Health Unit (MWHU) was implemented to improve mammogram screening of AI women in the Northern Plains. Our purpose was to determine the past adherence to screening mammography at a woman’s first presentation to the MWHU for mammogram screening. Date of the most recent prior non-MWHU mammogram was obtained from mammography records. Adherence to screening guidelines was defined as the prior mammogram occurring 1–2 years before the first MWHU visit among women ≥41 years, and was the main outcome, whereas, age and clinic site were predictors. Adherence was compared with national data of the Breast Cancer Surveillance Consortium (BCSC). Among 1,771 women ≥41 years, adherence to screening mammography guidelines was 48.01 % among ≥65 years, 42.05 % among 50–64 years, 33.43 % among 41–49 years, and varied with clinic site (25.23–65.93 %). Age (p <0.0001) and clinic site (p <0.0001) were associated with adherence. Overall, adherence to screening mammography guidelines was found in 39.86 % (706/1771) of MWHU women versus 74.34 % (747,095/1,004,943) of BCSC women. The majority (60.14 %) of women at first presentation to the MWHU had not had mammograms in the previous 2 years, lower screening adherence than nationally (25.66 %). Adherence was lowest among women ages 41–49, and varied with clinic site. Findings suggest disparities in mammography screening among these women.
Screening mammography; Health mobile; American Indians; Mammography adherence; Health disparities
Modulation of estrogen signaling is one of the most successful modalities for the treatment of estrogen receptor (ER)-positive breast cancer, yet de novo and acquired resistance are frequent. Recent data suggests that the induction of autophagy may play a considerable role in promoting tumor cell survival and resistance to anti-estrogen therapy. Hence, bypassing autophagy may offer a novel strategy to enhance the anti-tumor efficacy of anti-estrogens. Histone deacetylases (HDAC) are involved in the regulation of steroid hormone receptor mediated cell signaling and their inhibition potentiates the anti-tumor effects of anti-estrogens. However, the mechanism underlying this anti-tumor activity is poorly understood. In this report, we show that the addition of an HDAC inhibitor redirects the response of ER-positive breast cancer cells when treated with tamoxifen from growth arrest to apoptotic cell death. This redirection requires functional ER signaling and is mediated by a depletion of Bcl-2 and an induction of Bax and Bak, manifesting in cytochrome C release and PARP cleavage. With combined treatment, a subpopulation of cells are refractory to apoptosis and exhibit a strong induction of autophagy. Inhibition of autophagy in these cells, using siRNA directed against Beclin-1 or treatment with chloroquine, further promotes the induction of apoptosis. Thus, supporting prior reports that autophagy acts as a survival mechanism, our findings demonstrate that HDAC and autophagy inhibition directs autophagy-protected cells into apoptotic cell death, which may impair development of tamoxifen resistance.
breast cancer; histone deacetylase; anti-estrogen therapy; estrogen receptor; autophagy; apoptosis
RNF115, or Breast Cancer-Associated Gene 2 (BCA2), encodes a RING-finger ubiquitin E3 ligase, expression of which was associated with estrogen receptor (ER)-positive status in human breast tumors. Although the BCA2 promoter contains several estrogen response element (ERE) half-sites, the role of ER in the regulation of BCA2 transcription has not been reported. The aim of this study is to investigate the molecular mechanism by which estrogen regulates BCA2 transcription. BCA2 mRNA and protein levels were examined by RT-PCR and Western blot analysis, respectively, and localization was assessed by immunofluorescence. BCA2 promoter activity in response to E2 was tested by a dual luciferase reporter assay and ER binding to the BCA2 promoter was examined by chromatin immunoprecipitation assay. We found that BCA2 mRNA and protein levels are regulated by estrogen in ER-positive MCF7 breast cancer cells and MDA MB 231 cells stably transfected with ER. Estrogen treatment in hormonal depleted MCF7 and MDA MB 231/ER stably transfected cells resulted in increased nuclear ER and cytoplasmic and nuclear BCA2 staining. Cycloheximide is not able to inhibit BCA2 mRNA levels, suggesting potential BCA2 regulation at the transcriptional level. Anti-estrogens like tamoxifen and ICI 182 178 counteracted E2-induced BCA2 protein and knockdown of ER by ER siRNA resulted in a significant decrease in BCA2 protein and a lower nuclear expression pattern. Estrogen treatment lead to a significant increase in BCA2 promoter response, associated with increased binding of ER to the ERE region of the BCA2 promoter. BCA2 is therefore a newly identified transcriptional target of estrogen receptor.
Breast cancer; Estrogen receptor (ER); Breast cancer-associated gene 2 (BCA2); Estrogen (E2); Estrogen response element (ERE); Tamoxifen and ICI 182 178 (ICI)
Triple-negative breast cancer is a particularly aggressive and lethal breast cancer subtype that is more likely to be interval-detected rather than screen-detected. The purpose of this study is to discover and initially validate novel early detection biomarkers for triple-negative breast cancer using preclinical samples. Plasma samples collected up to 17 months prior to diagnosis from 28 triple-negative cases and 28 matched controls from the Women’s Health Initiative Observational Study were equally divided into a training set and a test set and interrogated using a customized antibody array. Data were available on 889 antibodies, and in the training set statistically significant differences in case vs. control signals were observed for 93 (10.5%) antibodies at p<0.05. Of these 93 candidates, 29 were confirmed in the test set at p<0.05. Areas under the curve for these candidates ranged from 0.58 to 0.79. With specificity set at 98%, sensitivity ranged from 4% to 68% with ≥20 candidates having a sensitivity 20% and 6 having a sensitivity ≥40%. In an analysis of KEGG gene sets, the pyrimidine metabolism gene set was upregulated in cases compared to controls (p=0.004 in the testing set) and the JAK/Stat signaling pathway gene set was downregulated (p=0.003 in the testing set). Numerous potential early detection biomarkers specific to triple-negative breast cancer in multiple pathways were identified. Further research is required to follow-up on promising candidates in larger sample sizes and to better understand their potential biological importance as our understanding of the etiology of triple-negative breast cancer continues to grow.
Breast cancer; triple-negative; biomarkers; early detection
It has been suggested that the concentrations of tamoxifen and its demethylated metabolites increase with age. We measured the serum concentrations of the active tamoxifen metabolites, 4OHtamoxifen (4OHtam), 4-hydroxy-N-desmethyltamoxifen (4OHNDtam, Endoxifen), tamoxifen and its demethylated metabolites. Their relations to age were examined. One hundred fifty-one estrogen receptor and/or progesterone receptor positive breast cancer patients were included. Their median (range) age was 57 (32–85) years. Due to the long half-life of tamoxifen, only patients treated with tamoxifen for at least 80 days were included in the study in order to insure that the patients had reached steady-state drug levels. Tamoxifen and its metabolites were measured by liquid chromatography-tandem mass spectrometry. Their serum concentrations were related to the age of the patients. To circumvent effects of cytochrome (CYP) 2D6 polymorphisms we also examined these correlations exclusively in homozygous extensive metabolizers. The concentrations of 4OHNDtam, tamoxifen, NDtam (N-desmethyltamoxifen), and NDDtam (N-desdimethyltamoxifen) were positively correlated to age (n = 151, p = 0.017, 0.045, 0.011, and 0.001 respectively). When exclusively studying the CYP2D6 homozygous extensive metabolizers (n = 86) the correlation between 4OHNDtam and age increased (p = 0.008). Up to tenfold inter-patient variation in the serum concentrations was observed. The median (inter-patient range) concentration of 4OHNDtam in the age groups 30–49, 50–69, and >69 years were 65 (24–89), 116 (25–141), and 159 (26–185) ng/ml, respectively. We conclude that the serum concentrations of 4OHNDtam (endoxifen), tamoxifen, and its demethylated metabolites increase with age during steady-state tamoxifen treatment. This may represent an additional explanation why studies on the effects of CYP2D6 polymorphisms on outcome in tamoxifen-treated breast cancer patients have been inconsistent. The observed high inter-patient range in serum concentrations of tamoxifen and its metabolites, especially in the highest age group, suggest that use of therapeutic monitoring of tamoxifen and its metabolites is warranted.
Tamoxifen; Metabolites; Age; Endoxifen; CYP2D6
We evaluated the use of sorafenib to overcome resistance to aromatase inhibitors (AIs) in patients with metastatic breast cancer who had disease recurrence or progression while on AIs. We performed a multi-institution phase I/II study of sorafenib and anastrozole 1 mg daily in 35 postmenopausal females with hormone receptor positive metastatic breast cancer resistant to AIs. Primary objectives were to determine the dose of sorafenib in conjunction with anastrozole and the clinical benefit rate (CBR) (complete response [CR], partial response [PR], or stable disease [SD] ≥ 24 weeks). Secondary objectives were to determine toxicity and to evaluate if response was associated with change in number of circulating endothelial cells or circulating endothelial progenitor cells. Based on the phase I portion, sorafenib 400 mg twice daily was selected as the phase II dose. Among 35 patients, 7 had SD ≥ 24 weeks, 1 had PR ≥ 24 weeks, and 14 had progressive disease (PD) ≤ 24 weeks, corresponding to a CBR of 23%. The most common adverse events (all; Grade 3/4) were fatigue (66%; 17%), diarrhea (63%; 6%), nausea (60%; 9%), and hand-foot syndrome (57%; 34%). Dose reduction occurred in 77% of the patients and 31% came off study due to toxicity. The combination of sorafenib and anastrozole demonstrated a 23% CBR in patients with hormone receptor positive, AI-resistant metastatic breast cancer, which may be attributable to the restoration of sensitivity to AIs. Toxicities occurred frequently resulting in a high rate of discontinuation.
Breast cancer; Endocrine resistance; Aromatase inhibitor; Anastrozole; Sorafenib
This pilot study aimed to investigate whether mammographic compression procedures might cause shedding of tumor cells into the circulatory system as reflected by circulating tumor cell (CTC) count in peripheral venous blood samples. From March to October 2012, 24 subjects with strong suspicion of breast malignancy were included in the study. Peripheral blood samples were acquired before and after mammography. Enumeration of CTCs in the blood samples was performed using the CellSearch® system. The pressure distribution over the tumor-containing breast was measured using thin pressure sensors. The median age was 66.5 years (range, 51–87 years). In 22 of the 24 subjects, breast cancer was subsequently confirmed. The difference between the average mean tumor pressure 6.8 ± 5.3 kPa (range, 1.0–22.5 kPa) and the average mean breast pressure 3.4 ± 1.6 kPa (range, 1.5–7.1 kPa) was statistically significant (p < 0.001), confirming that there was increased pressure over the tumor. The median pathological tumor size was 19 mm (range, 9–30 mm). Four subjects (17 %) were CTC positive before compression and two of these (8 %) were also CTC positive after compression. A total of seven CTCs were isolated with a mean size of 8 × 6 μm2 (range of the longest diameter, 5–12 μm). The study supports the view that mammography is a safe procedure from the point of view of tumor cell shedding to the peripheral blood.
Circulating tumor cells; Breast compression; Breast cancer; Mammography