Shedding light on azopolymer brush dynamics by fluorescence correlation spectroscopy.

Understanding the response to illumination at a molecular level as well as characterising polymer brush dynamics are key features that guide the engineering of new light-stimuli responsive materials. Here, we report on the use of a confocal microscopy technique that was exploited to discern how a single molecular event such as the photoinduced isomerisation of azobenzene can affect an entire polymeric material at a macroscopic level leading to photodriven mass-migration. For this reason, a set of polymer brushes, containing azobenzene (Disperse Red 1, DR) on the side chains of poly(methacrylic acid), was synthesised and the influence of DR on the polymer brush dynamics was investigated for the first time by Fluorescence Correlation Spectroscopy (FCS). Briefly, two dynamics were observed, a short one coming from the isomerisation of DR and a long one related to the brush main chain. Interestingly, photoinduced polymer aggregation in the confocal volume was observed.

Multiplex single particle analysis in microfluidics.

A straightforward way to measure separated micrometric sized particles in microfluidic flow is reported. The light scattering profile (LSP) of each single particle is fully characterized by using a CMOS-camera based small angle light scattering (SALS) apparatus, ranging from 2° up to 30°. To ensure controlled particle passage through the incident laser, a viscoelastic 3D alignment effect by viscoelastic induced particle migration has been implemented in a simple and cost-effective microfluidic device. Different polystyrene particle sizes are measured in microfluidic flows and the obtained scattering signatures are matched with the Lorenz-Mie based scattering theory. The results confirm the possibility of using this apparatus for real multiplex particle analyses in microfluidic particle flows.

Unraveling the clinicopathological and molecular changes induced by neoadjuvant chemotherapy and endocrine therapy in hormone receptor-positive/HER2-low and HER2-0 breast cancer.

BACKGROUND: The characterization and comparison of gene expression and intrinsic subtype (IS) changes induced by neoadjuvant chemotherapy (NACT) and endocrine therapy in hormone receptor-positive (HR+)/human epidermal growth factor receptor 2 (HER2)-low versus HR+/HER2-0 breast cancer (BC) has not been conducted so far. Most evidence on the association of HER2 status with pathologic responses and prognosis in HR+/HER2-negative BC is controversial and restricted to NACT-treated disease. Similarly, a temporal heterogeneity in HER2 status has been described only with NACT. METHODS: We retrospectively recruited a consecutive cohort of 186 patients with stage I-IIIB HR+/HER2-negative BC treated with neoadjuvant therapy (NAT). Available diagnostic biopsies and surgical samples were characterized for main pathological features, PAM50 IS and ROR-P score, and gene expression. Associations with pathologic complete response, residual cancer burden-0/I, event-free survival (EFS) and overall survival (OS) based on HER2 status were assessed. Pre/post pathologic/molecular changes were analyzed in matched samples. RESULTS: The HER2-low (62.9%) and HER2-0 (37.1%) cohorts did not differ significantly in main baseline features, treatments administered, breast-conserving surgery, pathologic complete response and residual cancer burden-0/I rates, EFS, and OS. NAT induced, regardless of HER2 status, a significant reduction of estrogen receptor/progesterone receptor and Ki67 levels, a down-regulation of PAM50 proliferation- and luminal-related genes/signatures, an up-regulation of selected immune genes, and a shift towards less aggressive IS and lower ROR-P. Moreover, 25% of HER2-0 changed to HER2-low and 34% HER2-low became HER2-0. HER2 shifts were significant after NACT (P < 0.001), not neoadjuvant endocrine therapy (P = 0.063), with consistent ERBB2 mRNA level dynamics. HER2 changes were not associated with EFS/OS. CONCLUSIONS: HER2-low and HER2-0 status change after NAT in ∼30% of cases, mostly after NACT. Targeted adjuvant strategies should be investigated accordingly. Molecular downstaging with current chemo/endocrine agents and immunotherapy should not rely on HER2 immunohistochemical levels in HR+/HER2-negative BC. Instead, HER2-low-targeted approaches should be explored to pursue more effective and/or less toxic dimensional downstaging.

Prognostic value of intrinsic subtypes in hormone-receptor-positive metastatic breast cancer: systematic review and meta-analysis.

BACKGROUND: In hormone receptor-positive (HoR+) breast cancer (BC), gene expression analysis identifies luminal A (LumA), luminal B (LumB), human epidermal growth factor receptor 2 (HER2)-enriched (HER2-E), basal-like (BL) intrinsic subtypes and a normal-like group. This classification has an established prognostic value in early-stage HoR+ BC. Here, we carried out a trial-level meta-analysis to determine the prognostic ability of subtypes in metastatic BC (MBC). MATERIALS AND METHODS: We systematically reviewed all the available prospective phase II/III trials in HoR+ MBC where subtype was assessed. The primary endpoint was progression-free survival (PFS)/time to progression (TTP) of the LumA subtype compared to non-LumA. Secondary endpoints were PFS/TTP of each individual subtype, according to treatment, menopausal and HER2 status and overall survival (OS). The random-effect model was applied, and heterogeneity assessed through Cochran's Q and I2. Threshold for significance was set at P < 0.05. The study was registered in PROSPERO (ID: CRD42021255769). RESULTS: Seven studies were included (2536 patients). Non-LumA represented 55.2% and was associated with worse PFS/TTP than LumA [hazard ratio (HR) 1.77, P < 0.001, I2 = 61%], independently of clinical HER2 status [Psubgroup difference (Psub) = 0.16], systemic treatment (Psub = 0.96) and menopausal status (Psub = 0.12). Non-LumA tumors also showed worse OS (HR 2.00, P < 0.001, I2 = 65%), with significantly different outcomes for LumB (PFS/TTP HR 1.46; OS HR 1.41), HER2-E (PFS/TTP HR 2.39; OS HR 2.08) and BL (PFS/TTP HR 2.67; OS HR 3.26), separately (PFS/TTP Psub = 0.01; OS Psub = 0.005). Sensitivity analyses supported the main result. No publication bias was observed. CONCLUSIONS: In HoR+ MBC, non-LumA disease is associated with poorer PFS/TTP and OS than LumA, independently of HER2, treatment and menopausal status. Future trials in HoR+ MBC should consider this clinically relevant biological classification.

Eribulin in combination with bevacizumab as second-line treatment for HER2-negative metastatic breast cancer progressing after first-line therapy with paclitaxel and bevacizumab: a multicenter, phase II, single arm trial (GIM11-BERGI).

BACKGROUND: We evaluated the efficacy and safety of the nontaxane microtubule dynamics inhibitor eribulin plus the humanized anti-VEGF monoclonal antibody bevacizumab in a novel second-line chemotherapy scheme in HER2-negative metastatic breast cancer (MBC) patients progressing after first-line paclitaxel and bevacizumab. PATIENTS AND METHODS: This is a multicenter, single-arm, Simon's two-stage, phase II study. The primary endpoint was the overall response rate, considered as the sum of partial and complete response based on the best overall response rate (BORR). The secondary endpoints were progression-free survival (PFS), overall survival (OS), and clinical benefit rate. RESULTS: A total of 58 of the 61 patients enrolled in the study were evaluable for efficacy. The BORR was 24.6% (95% CI 14.5-37.3). The clinical benefit rate was 32.8% (95% CI 21.3-46.0). The median PFS was 6.2 months (95% CI 4.0-7.8), and median OS was 14.8 months (95% CI 12.6-22.8). Overall, adverse events (AEs) were clinically manageable and the most common AEs were fatigue, paresthesia, and neutropenia. Quality of life was well preserved in most patients. CONCLUSIONS: The results of this study suggest that second-line therapy with bevacizumab in combination with eribulin has a meaningful clinical activity and may represent a potential therapeutic option for patients with HER2-negative MBC.

Androgen receptor in triple negative breast cancer: A potential target for the targetless subtype.

Triple negative breast cancer (TNBC) represents the 15-20% of all breast cancers (BC) and is characterized by a very aggressive behavior. Recent data suggest that TNBC is not a single disease, but it is rather an umbrella for different ontology-profiles such as basal like 1 and 2, mesenchymal, and the luminal androgen receptor (LAR). The LAR subtype is characterized by the expression of the Androgen Receptor (AR) and its downstream effects. Notwithstanding the role of the AR in several signaling pathways, its impact on a biological and clinical standpoint is still controversial. The LAR subtype has been associated with better prognosis, less chemotherapy responsiveness and lower pathologic complete response after neoadjuvant treatment. Clinical evidence suggests a role for anti-androgen therapies such as bicalutamide, enzalutamide and abiraterone, offering an interesting chemo-free alternative for chemo-unresponsive patients, and therefore potentially shifting current treatment strategies.