Clinical and biological impact of miR-18a expression in breast cancer after neoadjuvant chemotherapy.

PURPOSE: The analysis of breast cancer residual tumors after neoadjuvant chemotherapy (nCT) may be useful for identifying new biomarkers. MicroRNAs are known to be involved in oncogenic pathways and treatment resistance of breast cancer. Our aim was to determine the role of miR-18a, a member of the miR-17-92a cluster, in breast cancer behavior and outcome after nCT. METHODS: Pre- and post-nCT tumor miR-18a expression was retrospectively assessed by qRT-PCR in 121 patients treated with nCT and was correlated with survival outcomes and with clinical and pathological characteristics. Breast cancer-derived MCF-7 and MDA-MB-231 cell lines were transfected with miR-18a and anti-miR-18a to evaluate the biological effects of this molecule. In addition, whole-transcriptome expression analysis was performed. RESULTS: High miR-18a expression in post-nCT residual tumors was found to be associated with a significantly worse overall survival [hazard ratio (HR): 2.80, 95% confidence interval (CI): 1.01-7.76] and a strong trend towards a poorer disease-free survival (HR: 2.44, 95% CI: 0.99-5.02) compared to low miR-18a expressing post-nCT residual tumors. Clinical and experimental data were found to be in conformity with the proliferative effects of miR-18a, which showed a significant correlation with Ki67 and MYBL2 expression, both in pre- and post-nCT tumors and in public databases. In vitro analysis of the role of miR-18a in breast cancer-derived cell lines showed that a high expression of miR-18a was associated with a low expression of the estrogen receptor (ER), a decreased sensitivity to tamoxifen and an enrichment in luminal B and endocrine resistance gene expression signatures. CONCLUSIONS: From our data we conclude that post-nCT miR-18a expression in breast cancer serves as a negative prognostic marker, especially in luminal tumors. Clinical, in vitro and in silico data support the role of miR-18a in breast cancer cell proliferation and endocrine resistance and suggest its potential utility as a biomarker for additional adjuvant treatment in patients without a pathologic complete response to neoadjuvant therapy.

Plasma Androgen Receptor Copy Number Status at Emergence of Metastatic Castration-Resistant Prostate Cancer: A Pooled Multicohort Analysis.

PURPOSE: Increases in androgen receptor (AR) copy number (CN) can be detected in plasma DNA when patients develop metastatic castration-resistant prostate cancer. We aim to evaluate the association between AR CN as a continuous variable and clinical outcome. PATIENTS AND METHODS: PCR2023 was an international, multi-institution, open-label, phase II study of abiraterone acetate plus prednisolone (AAP) or abiraterone acetate plus dexamethasone that included plasma AR assessment as a predefined exploratory secondary end point. Plasma AR CN data (ClinicalTrials.gov identifier: NCT01867710) from this study (n = 133) were pooled with data from the following three other cohorts: cohort A, which was treated with either AAP or enzalutamide (n = 73); the PREMIERE trial (ClinicalTrials.gov identifier: NCT02288936) of biomarkers for enzalutamide (n = 94); and a phase II trial from British Columbia (ClinicalTrials.gov identifier: NCT02125357) that randomly assigned men to either AAP or enzalutamide (n = 201). The primary outcome measures for the biomarker analysis were overall survival and progression-free survival. RESULTS: Using multivariable fractional polynomials analysis using Cox regression models, a nonlinear relationship between plasma AR CN and outcome was identified for overall survival, where initially for small incremental gains in CN there was a large added hazard ratio that plateaued at higher CN. The CN cut point associated with the highest local hazard ratio was 1.92. A similar nonlinear association was observed with progression-free survival. In an exploratory analysis of PCR2023, the time from start of long-term androgen-deprivation therapy to start of AAP or abiraterone acetate plus dexamethasone was significantly shorter in patients with plasma AR CN of 1.92 or greater than patients with plasma AR CN of less than 1.92 (43 v 130 weeks, respectively; P = .005). This was confirmed in cohort A (P = .003), the PREMIERE cohort (P = .03), and the British Colombia cohort (P = .003). CONCLUSION: Patients with metastatic castration-resistant prostate cancer can be dichotomized by a plasma AR CN cut point of 1.92. Plasma AR CN value of 1.92 or greater identifies aggressive disease that is poorly responsive to AR targeting and is associated with a prior short response to primary androgen-deprivation therapy.

Safety evaluation and nutritional composition of a Fraxinus excelsior seed extract, FraxiPure™.

A natural extract obtained from the seeds of Fraxinus excelsior L. (FraxiPure™) has been previously reported to reduce glycemia in animal models and in humans. The objective of this work was to evaluate the safety of FraxiPure™ at in vitro, in vivo and human levels. In addition, nutritional analyses revealed an extract high in carbohydrates, with minor levels of protein, dietary fiber, glucose and sucrose. IC(50) and IC(90) values of 1.447 and 2.530 mg/mL, respectively, after 72 h incubation were calculated using the MTT assay. FraxiPure™ conferred a magnitude of protection of 69.2% against the formation of micronuclei in irradiated human lymphocytes as determined by the micronucleus assay. An LD(50) of greater than 2500 mg/kg was concluded following an acute oral toxicity study in Sprague-Dawley rats. A human safety evaluation in a double-blind, placebo-controlled parallel study of 100 healthy volunteers revealed no significant differences between daily consumption of 1000 mg of FraxiPure™ for 90 days and placebo (maltodextrin) for any of the biochemical or hematological parameters studied. Numbers of adverse events were similar in both groups, and were deemed mild to moderate. These results demonstrate, for the first time, the safety and tolerability of FraxiPure™ for consumption in healthy subjects.