MicroRNA-584 and the protein phosphatase and actin regulator 1 (PHACTR1), a new signaling route through which transforming growth factor-ß Mediates the migration and actin dynamics of breast cancer cells.

TGF-ß plays an important role in breast cancer progression as a prometastatic factor, notably through enhancement of cell migration. It is becoming clear that microRNAs, a new class of small regulatory molecules, also play crucial roles in mediating tumor formation and progression. We found TGF-ß to down-regulate the expression of the microRNA miR-584 in breast cancer cells. Furthermore, we identified PHACTR1, an actin-binding protein, to be positively regulated by TGF-ß in a miR-584-dependent manner. Moreover, we found TGF-ß-mediated down-regulation of miR-584 and increased expression of PHACTR1 to be required for TGF-ß-induced cell migration of breast cancer cells. Indeed, both overexpression of miR-584 and knockdown of PHACTR1 resulted in a drastic reorganization of the actin cytoskeleton and reduced TGF-ß-induced cell migration. Our data highlight a novel signaling route whereby TGF-ß silences the expression of miR-584, resulting in enhanced PHACTR1 expression, and further leading to actin rearrangement and breast cancer cell migration.

Breast cancer anti-estrogen resistance 3 inhibits transforming growth factor ß/Smad signaling and associates with favorable breast cancer disease outcomes.

INTRODUCTION: This study helps to define the implications of breast cancer anti-estrogen resistance 3 (BCAR3) in breast cancer and extends the current understanding of its molecular mechanism of action. BCAR3 has been shown to promote cell proliferation, migration and attachment to extracellular matrix components. However, in a cohort of metastatic breast cancer patients who received tamoxifen treatment, high BCAR3 mRNA levels were associated with favorable progression-free survival outcome. These results suggest that, besides its established roles, BCAR3 may have additional mechanisms of action that regulate breast cancer aggressive phenotype. In this study, we investigated whether BCAR3 is a novel antagonist of the canonical transforming growth factor ß (TGFß) pathway, which induces potent migration and invasion responses in breast cancer cells. METHODS: We surveyed functional genomics databases for correlations between BCAR3 expression and disease outcomes of breast cancer patients. We also studied how BCAR3 could regulate the TGFß/Smad signaling axis using Western blot analysis, coimmunoprecipitation and luciferase assays. In addition, we examined whether BCAR3 could modulate TGFß-induced cell migration and invasion by using an automated imaging system and a confocal microscopy imaging-based matrix degradation assay, respectively. RESULTS: Relatively low levels of BCAR3 expression in primary breast tumors correlate with poor distant metastasis-free survival and relapse-free survival outcomes. We also found a strong correlation between the loss of heterozygosity at BCAR3 gene alleles and lymph node invasion in human breast cancer, further suggesting a role for BCAR3 in preventing disease progression. In addition, we found BCAR3 to inhibit Smad activation, Smad-mediated gene transcription, Smad-dependent cell migration and matrix digestion in breast cancer cells. Furthermore, we found BCAR3 to be downregulated by TGFß through proteasome degradation, thus defining a novel positive feedback loop mechanism downstream of the TGFß/Smad signaling pathway. CONCLUSION: BCAR3 is considered to be associated with aggressive breast cancer phenotypes. However, our results indicate that BCAR3 acts as a putative suppressor of breast cancer progression by inhibiting the prometastatic TGFß/Smad signaling pathway in invasive breast tumors. These data provide new insights into BCAR3's molecular mechanism of action and highlight BCAR3 as a novel TGFß/Smad antagonist in breast cancer.

Improving implementation of best practices in obesity management: Physician experiences in obesity care.

In this study, we sought to analyse experiences in weight management among physicians working in the area of obesity and contrast these experiences with best practices. By understanding experiences of physicians working in obesity management, we can better support implementation of best practices in their day-to-day practice. An online survey of Canadian primary care physicians, internists and endocrinologists recruited from a nationwide market research database was conducted. The survey captured demographic characteristics and perceptions about weight loss and its management. One hundred and ninety-two physicians (140 primary care, 22 internists and 30 endocrinologists) were recruited and completed the survey. Challenges identified by the physicians in helping patients lose weight included patients' poor compliance and lack of time and resources to address the issue. Most physicians reported considering obesity to be a chronic disease, but most did not incorporate a multi-dimensional, chronic disease model of obesity treatment (i.e., combination of lifestyle interventions with psychological, medical and/or surgical interventions). Endocrinologists reported management practices consistent with a chronic disease model more frequently than primary care physicians. These data highlight the need for improvement in obesity management, particularly in primary care. Despite proliferation of guidelines on best practices, implementation of these practices into daily practice remains low.

Cyclin D1 cooperates with p21 to regulate TGFß-mediated breast cancer cell migration and tumor local invasion.

INTRODUCTION: Deregulation of the cell cycle machinery is often found in human cancers. Modulations in the cell cycle regulator function and expression result not only in proliferative advantages, but also lead to tumor progression and invasiveness of the cancer. In particular, cyclin D1 and p21 are often over-expressed in human cancers, correlating with high tumor grade, poor prognosis and increased metastasis. This prompted us to investigate the role of the cyclin D1/p21 signaling axis downstream of transforming growth factor beta (TGFß) in breast cancer progression. METHODS: Cyclins mRNA and protein expressions were assessed by quantitative real-time PCR and Western blot in triple negative breast cancer cell lines. Co-localization and interaction between cyclin D1 and p21 were performed by immunocytochemistry and co-immunoprecipitation, respectively. Cell migration was assessed by wound healing and quantitative time-lapse imaging assays. In addition, the effects of cyclin D1 on cellular structure and actin organization were examined by staining with F-actin marker phalloidin and mesenchymal intermediate filament vimentin. Finally, a mammary fat pad xenograft mouse model was used to assess mammary tumor growth and local invasion. RESULTS: We found TGFß to specifically up-regulate the expression of cyclin D1 in triple negative breast cancer cells. Induction of cyclin D1 is also required for TGFß-mediated cell migration. Suppression of cyclin D1 expression not only resulted in a rounded and epithelial-like phenotype, but also prevented TGFß-induced vimentin and F-actin co-localization at the cell edge as well as invadopodia formation. Furthermore, TGFß promoted the nuclear co-localization and physical interaction between cyclin D1 and p21. The co-expression of cyclin D1 and p21 proteins are required for the initial steps of tumor development, as double knockdown of these two molecules prevented primary tumor formation in a Xenograft mouse model. Moreover, the in vivo studies indicated that locally advanced features of the invasive tumors, including skeletal muscle, mammary fat pad and lymphovascular invasion, as well as ulcerated skin, were attenuated in the absence of cyclin D1 and p21. CONCLUSIONS: Thus, our findings highlight the cyclin D1/p21 signaling axis as a critical regulator of TGFß-mediated tumor growth initiation and local tumor cell invasion, both in vitro and in vivo.

Development of buffers for fast semidry transfer of proteins.

Western blot is an extensively used method for protein detection in cell biology. To optimize this procedure, here we examined a panel of buffers for their ability to efficiently transfer proteins from SDS-polyacrylamide gels onto nitrocellulose membranes in a short 12-min period, designated here as fast semidry transfer. Our results show for the first time that HEPES- and HEPPS/EPPS-based buffers represent the most efficient buffers for fast semidry transfer.

The relationship between early weight loss and weight loss maintenance with naltrexone-bupropion therapy.

Background: Extended-release (ER) naltrexone/bupropion (NB) was associated with greater weight loss than placebo in four randomized, 56-week trials. The association of NB with longer-term maintenance of weight loss remains unknown. Methods: We conducted a post-hoc analysis of four phase III, randomized, double-blind, placebo-controlled, 56-week studies (COR-I, COR-II, COR-BMOD, and COR-DM), the placebo-controlled cardiovascular outcomes trial LIGHT (208 weeks), and the randomized, open-label trial IGNITE (78 weeks). Included subjects were treated with NB 32 mg/360 mg or placebo, with baseline, week 16, and final time point data. The primary outcome was Kaplan-Meier-estimated weight loss maintenance in each study for up to 204 weeks. Findings: Our analysis included data from 10,198 particpants (NB=5412; placebo=4786). Proportions of patients with ≥5% or ≥10% weight loss maintenance were numerically higher for NB vs. placebo in all studies and time points. Differences were statistically significant for ≥5% weight loss maintenance in COR-BMOD and COR-I/-II at weeks 52 and 56 and the LIGHT study at weeks 52, 104, and 208. For ≥10% weight loss maintenance, differences were statistically significant in COR-I/COR-II at weeks 52 and 56. Interpretation: These data suggest that NB could be used as part of long-term, comprehensive weight loss and weight loss maintenance strategies. Funding: Orexigen Therapeutics, Inc. and Bausch Health Canada.

Regional variability in Canadian routine care of type 2 diabetes, hypercholesterolemia, and hypertension: Results from the The Cardio-Vascular and metabolic treatments in Canada: Assessment of REal-life therapeutic value (CV-CARE) registry.

BACKGROUND: Regional differences in the profile and treatment strategies of patients with cardiometabolic diseases have been studied in several different countries. The Cardio-Vascular and metabolic treatments in Canada: Assessment of REal-life therapeutic value (CV-CARE) registry was designed to evaluate patient profiles and medical management of cardiometabolic diseases in routine clinical care settings across Canada. Primary objectives were to (1) evaluate regional variability of patient profiles with cardiometabolic disease(s) and (2) assess treatment differences of patients treated for type 2 diabetes (T2D), hypercholesterolemia (HCh), and hypertension (HTN) across Canada. METHODS: CV-CARE is a multi-center, observational, prospective registry that enrolled Canadian patients treated with metformin-extended release (MetER) for T2D, colesevelam (C) for HCh, azilsartan (AZI) for mild-to-moderate essential HTN and azilsartan/chlorthalidone (AZI/CHL) for severe, essential HTN. Patient characteristics and treatments were assessed at baseline. RESULTS: The registry enrolled 6960 patients, with a total of 4194 patients making up the primary analysis population [MetER (n=995); C (n=1639); AZI (n=1364); AZI/CHL (n=498)]. First-line use of MetER was more common in British Columbia (BC; 45.5%) compared to Ontario (ON; 29.8%), and Quebec (QC; 12.9%). C treatment for HCh was used as monotherapy most readily in BC (68.7%) compared with QC (59.7%) and ON (35.8%). Dual action of low-density lipoprotein cholesterol and hemoglobin A1c reduction was the predominant reason for C add-on therapy (46.8%), with highest usage seen in ON (62.9%). AZI treatment for HTN was most frequently used in BC (43.8%), and AZI/CHL was most commonly used in ON (12.0%). First-line use of AZI was more common in QC (50%) vs. ON (34.9%) and BC (24.1%). The primary reason for switching to AZI and AZI/CHL from prior treatment was lack of efficacy across provinces. CONCLUSION: This is the first regional description of the CV-CARE cohort. Significant variations in both baseline profile and treatments were observed which could have an impact on long-term outcomes.

Real-world effectiveness of treatments for type 2 diabetes, hypercholesterolemia, and hypertension in Canadian routine care - Results from the CardioVascular and metabolic treatment in Canada: Assessment of REal-life therapeutic value (CV-CARE) registry, 12-months results.

AIMS: The CV-CARE registry provides RWE in Canadian routine clinical practice. METHODS: CV-CARE is a multi-site, observational, prospective Canadian registry enrolling patients initiating treatment with metformin hydrochloride extended-release (MetER) for T2D; colesevelam (C) for HCh; and azilsartan (AZI), azilsartan/chlorthalidone (AZI/CHL) or diltiazem extended-release (TXC) for HTN. Patient characteristics/assessment were performed at baseline and 12 ± 6 months. Primary outcome was absolute change in HbA1c and FPG (MetER); % change in LDL-C (C); and absolute change in BP (AZI-AZI/CHL-TXC). RESULTS: Of the 4194 patients in the primary analysis population, 24% were taking MetER, 39% were taking C, 33% were taking AZI, 12% were taking AZI/CHL, and 3% were taking TXC. At 12 months, MetER-treated patients had an absolute mean (95% CI) change in HbA1c of -0.3% [-0.4; -0.2] and in FPG of 0.7 mmol/L [-1.0; -0.4]. C-treated patients had a mean (95% CI) % change in LDL-C of -13.0% [-14.6; -11.4]. Absolute mean (95% CI) changes in SBP were -18.7 mmHg [-19.7; -17.7](AZI), -21.3 mmHg [-23.1; -19.5](AZI/CHL), and -12.3 mmHg [-15.1; -9.6](TXC). CONCLUSION: In a real-world Canadian setting, MetER, C, AZI, AZI/CHL, and TXC show improvement of the cardiometabolic profile of T2D, HCh, and HTN patients.

CDK4 regulates cancer stemness and is a novel therapeutic target for triple-negative breast cancer.

Triple negative breast cancers exhibit very aggressive features and poor patient outcomes. These tumors are enriched in cancer stem cells and exhibit resistance to most treatments and chemotherapy. In this study, we found the cyclin-dependent kinase (CDK4) to act as a cancer stem cell regulator and novel prognostic marker in triple negative breast cancers. We found CDK4 to be highly expressed in these tumors and its expression to correlate with poor overall and relapse free survival outcomes, high tumor grade and poor prognostic features of triple negative breast cancer patients. Moreover, we found that blocking CDK4 expression or kinase activity, using a pharmacological inhibitor prevented breast cancer stem cell self-renewal. Interestingly, suppression of CDK4 expression or kinase activity reversed the basal-B TNBC mesenchymal phenotype to an epithelial- and luminal-like phenotype which correlates with better clinical prognosis. Finally, blocking CDK4 activity efficiently eliminated both normal and chemotherapy-resistant cancer cells in triple negative breast cancers, highlighting CDK4 as a promising novel therapeutic target for these aggressive breast tumors.