Patient-derived xenograft (PDX) models in basic and translational breast cancer research

Patient-derived xenograft (PDX) models of a growing spectrum of cancers are rapidly supplanting long-established traditional cell lines as preferred models for conducting basic and translational preclinical research. In breast cancer, to complement the now curated collection of approximately 45 long-established human breast cancer cell lines, a newly formed consortium of academic laboratories, currently from Europe, Australia, and North America, herein summarizes data on over 500 stably transplantable PDX models representing all three clinical subtypes of breast cancer (ER+, HER2+, and "Triple-negative" (TNBC)). Many of these models are well-characterized with respect to genomic, transcriptomic, and proteomic features, metastatic behavior, and treatment response to a variety of standard-of-care and experimental therapeutics. These stably transplantable PDX lines are generally available for dissemination to laboratories conducting translational research, and contact information for each collection is provided. This review summarizes current experiences related to PDX generation across participating groups, efforts to develop data standards for annotation and dissemination of patient clinical information that does not compromise patient privacy, efforts to develop complementary data standards for annotation of PDX characteristics and biology, and progress toward "credentialing" of PDX models as surrogates to represent individual patients for use in preclinical and co-clinical translational research. In addition, this review highlights important unresolved questions, as well as current limitations, that have hampered more efficient generation of PDX lines and more rapid adoption of PDX use in translational breast cancer research

Recent advances reveal IL-8 signaling as a potential key to targeting breast cancer stem cells

Breast cancer stem-like cells (CSCs) are an important therapeutic target as they are purported to be responsible for tumor initiation, maintenance, metastases, and disease recurrence. Interleukin-8 (IL-8) is upregulated in breast cancer compared with normal breast tissue and is associated with poor prognosis. IL-8 is reported to promote breast cancer progression by increasing cell invasion, angiogenesis, and metastases and is upregulated in HER2-positive cancers. Recently, we and others have established that IL-8 via its cognate receptors, CXCR1 and CXCR2, is also involved in regulating breast CSC activity. Our work demonstrates that in metastatic breast CSCs, CXCR1/2 signals via transactivation of HER2. Given the importance of HER2 in breast cancer and in regulating CSC activity, a pathway driving the activation of these receptors would have important biological and clinical consequences, especially in tumors that express high levels of IL-8 and other CXCR1/2-activating ligands. Here, we review the IL-8 signaling pathway and the role of HER2 in maintaining an IL-8 inflammatory loop and discuss the potential of combining CXCR1/2 inhibitors with other treatments such as HER2-targeted therapy as a novel approach to eliminate CSCs and improve patient survival

Bioprosthetic xenopericardium preserved with di- and penta-epoxy compounds: molecular cross-linking mechanisms, surface features and mechanical properties

Background. Heart valve bioprostheses made from glutaraldehyde-treated bovine and porcine pericardia are widely used in open and transcatheter valve surgeries. However, the glutaraldehyde cross-linkage leads to bioprosthetic calcification in many patients. Epoxides are advantageous alternatives to glutaraldehyde, since they engender the biomaterial with better calcification resistance. The cross-linking features of an epoxy compound depend on its chemical structure and have not been fully studied so far. Aim. The study is aimed at comparing the effectiveness and molecular mechanisms of biomaterial treatment using diepoxide vs pentaepoxide compounds. Methods. We studied the stability of diepoxide and pentaepoxide in water and aqueous buffered solutions, as well as the amino acid composition, type of epoxide links with collagen matrix (infrared spectroscopy) and mechanical properties of bovine and porcine pericardia treated with 5% diepoxide, a mixture of 2% diepoxide and 1% pentaepoxide, and with alternating 5% diepoxide and 2% pentaepoxide treatments. Results. Diepoxide and pentaepoxide are both stable in aqueous buffer solutions (pH 7.4). Diepoxide provides high linkage density in bovine and porcine pericardia due to reactions with the amino groups of the OHLys, Lys, His, and Arg residues, and the hydroxyl groups of OHPro, Ser, and Tyr, while pentaepoxide reacts only with Met. Pentaepoxide enhances the strength and elasticity of the xenopericardium. Specimens consecutively treated with diepoxide and pentaepoxide were significantly thinner and featured the highest maximal tensile stress, maximal strain and elastic modulus in comparison with tissues treated with 5% diepoxide and diepoxide-pentaepoxide mixture. Conclusion. The alternating diepoxide-pentaepoxide combination for biomaterial cross-linking is a promising trend for bioprosthetic pericardium treatment