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SummaryThe inter- and intra-tumor heterogeneity of breast cancer needs to be adequately captured in pre-clinical models. We have created a large collection of breast cancer patient-derived tumor xenografts (PDTXs), in which the morphological and molecular characteristics of the originating tumor are preserved through passaging in the mouse. An integrated platform combining in vivo maintenance of these PDTXs along with short-term cultures of PDTX-derived tumor cells (PDTCs) was optimized. Remarkably, the intra-tumor genomic clonal architecture present in the originating breast cancers was mostly preserved upon serial passaging in xenografts and in short-term cultured PDTCs. We assessed drug responses in PDTCs on a high-throughput platform and validated several ex vivo responses in vivo. The biobank represents a powerful resource for pre-clinical breast cancer pharmacogenomic studies (http://caldaslab.cruk.cam.ac.uk/bcape), including identification of biomarkers of response or resistance.

Patients with cancer experience higher burden of SARS-CoV-2 infection, disease severity, complications, and mortality, than the general population. SARS-CoV-2 mRNA vaccines are highly effective in the general population; however, few data are available on their efficacy in patients with cancer. Using a prospective cohort, we assessed the seroconversion rates and anti-SARS-CoV-2 spike protein antibody titers following the 1 st and 2 nd dose of BNT162b2 and mRNA-1273 SARS-CoV-2 vaccines in patients with cancer in U.S. and Europe from January to April 2021. Among 131 patients, most (94%) achieved seroconversion after receipt of 2 vaccine doses. Seroconversion rates and antibody titers in patients with hematological malignancy were significantly lower than those with solid tumors. None of the patients with history of anti-CD-20 antibody in the 6 months prior to vaccination developed antibody response. Antibody titers were highest for clinical surveillance or endocrine therapy groups and lowest for cytotoxic chemotherapy or monoclonal antibody group.

The role of transforming growth factor-beta (TGFβ) in the progression of different molecular subtypes of breast cancer has not been clarified. Here we show that TGFβ increases breast tumour-initiating cell (BTIC) numbers but only in claudin low breast cancer cell lines by orchestrating a specific gene signature enriched in stem cell processes that predicts worse clinical outcome in breast cancer patients. nEDD9, a member of the Cas family of integrin scaffold proteins, is necessary to mediate these TGFβ-specific effects through a positive feedback loop that integrates TGFβ/smad and Rho-actin-sRF-dependent signals. In normal human mammary epithelium, TGFβ induces progenitor activity only in the basal/stem cell compartment, where claudin low cancers are presumed to arise. These data show opposing responses to TGFβ in both breast malignant cell subtypes and normal mammary epithelial cell subpopulations and suggest therapeutic strategies for a subset of human breast cancers.

Intracellular recycling pathways play critical roles in internalizing membrane and fluid phase cargo and in balancing the inflow and outflow of membrane and cell surface molecules. To identify proteins involved in the regulation of endocytic recycling, we used an shRNA trafficking library and screened for changes in the surface expression of CD1a antigen-presenting molecules that follow an endocytic recycling route. We found that silencing of the ADP-ribosylation factor (Arf)-like small GTPase Arl13b led to a decrease in CD1a surface expression, diminished CD1a function, and delayed CD1a recycling, suggesting that Arl13b is involved in the regulation of endocytic recycling traffic. Arl13b appears to be required for the major route of endocytic trafficking, causing clustering of early endosomes and leading to the accumulation of endocytic cargo. Moreover, Arl13b colocalized with markers of the endocytic recycling pathway followed by CD1a, namely Arf6 and Rab22a. We also detected an interaction between Arl13b and the actin cytoskeleton. Arl13b was previously implicated in cilia formation and function. Our present results indicate a previously unidentified role for Arl13b in endocytic recycling traffic and suggest a link between Arl13b function and the actin cytoskeleton.immune response | lipid antigens | ciliary traffic | vesicle traffic E ukaryotic cells sample the extracellular milieu to take up fluid and receptor-bound ligands. Many receptors release their ligands in the mildly acidic environment of early endosomes. From this compartment, also known as the sorting endosome, membrane-bound receptors and other plasma membrane proteins can recycle back to the plasma membrane, whereas fluid phase cargo and membrane proteins destined for utilization or degradation follow the endocytic pathway to late endosomes and lysosomes. Recycling back to the plasma membrane can occur via a fast recycling pathway or, alternatively, a slow recycling pathway through the perinuclear endocytic recycling compartment (ERC). Cells take up considerable amounts of membrane from the cell surface; thus, recycling pathways are essential to return membrane, membrane proteins, and lipids to the cell surface, balancing the internalized flow. Along with this function, regulated recycling has been shown to be important for cytokinesis, cell adhesion, morphogenesis, cell fusion, and even learning and memory (1).However, the machinery involved in the sorting and trafficking of recycling cargo through the ERC remains incompletely understood. We previously reported that CD1a, an MHC class I-like antigen-presenting molecule that presents lipids rather than peptides to T cells, follows an endocytic recycling pathway similar to that used by MHC class I and other cargo internalized independent of clathrin (2). This pathway has been shown to depend on the small GTPases Rab22a and Arf6 (3, 4).To uncover previously unknown proteins involved in regulation of the endocytic recycling pathway followed by CD1a and other clathrin-independent cargo, we developed ...

Background and Purpose Inflammatory biomarkers predict incident and recurrent cardiac events, but their relationship to stroke prognosis is uncertain. We hypothesized that high-sensitivity C-reactive protein (hsCRP) predicts recurrent ischemic stroke after recent lacunar stroke. Methods Levels of Inflammatory Markers in the Treatment of Stroke (LIMITS) was an international, multicenter, prospective ancillary biomarker study nested within Secondary Prevention of Small Subcortical Strokes (SPS3), a Phase III trial in patients with recent lacunar stroke. Patients were assigned in factorial design to aspirin versus aspirin plus clopidogrel, and higher versus lower blood pressure targets. Patients had blood samples collected at enrollment, and hsCRP measured using nephelometry at a central laboratory. Cox proportional hazards models were used to calculate hazard ratios and 95% confidence intervals (HR, 95%CI) for recurrence risks before and after adjusting for demographics, comorbidities, and statin use. Results Among 1244 lacunar stroke patients (mean 63.3 ± 10.8 years), median hsCRP was 2.16 mg/L. There were 83 recurrent ischemic strokes (including 45 lacunes), and 115 major vascular events (stroke, myocardial infarction, vascular death). Compared with the bottom quartile, those in the top quartile (hsCRP >4.86 mg/L) were at increased risk of recurrent ischemic stroke (unadjusted HR 2.54, 95%CI 1.30–4.96), even after adjusting for demographics and risk factors (adjusted HR 2.32, 95%CI 1.15–4.68). HsCRP predicted increased risk of major vascular events (top quartile adjusted HR 2.04, 95%CI 1.14–3.67). There was no interaction with randomized antiplatelet treatment. Conclusions Among recent lacunar stroke patients, hsCRP levels predict risk of recurrent strokes and other vascular events. HsCRP did not predict response to dual antiplatelets.

Expression of the transcription factor SOX4 is often elevated in human cancers, where it generally correlates with tumor-progression and poor-disease outcome. Reduction of SOX4 expression results in both diminished tumor-incidence and metastasis. In breast cancer, TGF-β-mediated induction of SOX4 has been shown to contribute to epithelial-to-mesenchymal transition (EMT), which controls pro-metastatic events. Here, we identify SMAD3 as a novel, functionally relevant SOX4 interaction partner. Genome-wide analysis showed that SOX4 and SMAD3 co-occupy a large number of genomic loci in a cell-type specific manner. Moreover, SOX4 expression was required for TGF-β-mediated induction of a subset of SMAD3/SOX4-co-bound genes regulating migration and extracellular matrix-associated processes, and correlating with poor-prognosis. These findings identify SOX4 as an important SMAD3 co-factor controlling transcription of pro-metastatic genes and context-dependent shaping of the cellular response to TGF-β. Targeted disruption of the interaction between these factors may have the potential to disrupt pro-oncogenic TGF-β signaling, thereby impairing tumorigenesis.

The expression of the transcription factor SOX4 is increased in many human cancers, however, the pro-oncogenic capacity of SOX4 can vary greatly depending on the type of tumor. Both the contextual nature and the mechanisms underlying the pro-oncogenic SOX4 response remain unexplored. Here, we demonstrate that in mammary tumorigenesis, the SOX4 transcriptional network is dictated by the epigenome and is enriched for pro-angiogenic processes. We show that SOX4 directly regulates endothelin-1 (ET-1) expression and can thereby promote tumor-induced angiogenesis both in vitro and in vivo. Furthermore, in breast tumors, SOX4 expression correlates with blood vessel density and size, and predicts poor-prognosis in patients with breast cancer. Our data provide novel mechanistic insights into context-dependent SOX4 target gene selection, and uncover a novel pro-oncogenic role for this transcription factor in promoting tumor-induced angiogenesis. These findings establish a key role for SOX4 in promoting metastasis through exploiting diverse pro-tumorigenic pathways.