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Breast cancer-induced inflammation in the tumor reactive stroma supports invasion and malignant progression and is contributed to by a variety of host cells including macrophages and fibroblasts. Inflammation appears to be initiated by tumor cells and surrounding host fibroblasts that secrete pro-inflammatory cytokines and chemokines and remodel the extracellular matrix (ECM) to create a pro-inflammatory “cancerized” or tumor reactive microenvironment that supports tumor expansion and invasion. The tissue polysaccharide hyaluronan (HA) is an example of an ECM component within the cancerized microenvironment that promotes breast cancer progression. Like many ECM molecules, the function of native high-molecular weight HA is altered by fragmentation, which is promoted by oxygen/nitrogen free radicals and release of hyaluronidases within the tumor microenvironment. HA fragments are pro-inflammatory and activate signaling pathways that promote survival, migration, and invasion within both tumor and host cells through binding to HA receptors such as CD44 and RHAMM/HMMR. In breast cancer, elevated HA in the peri-tumor stroma and increased HA receptor expression are prognostic for poor outcome and are associated with disease recurrence. This review addresses the critical issues regarding tumor-induced inflammation and its role in breast cancer progression focusing specifically on the changes in HA metabolism within tumor reactive stroma as a key factor in malignant progression.

SUMMARYHere we demonstrate that GmMYB176 regulates CHS8 expression and affects isoflavonoid synthesis in soybean. We previously established that CHS8 expression determines the isoflavonoid level in soybean seeds by comparing the transcript profiles of cultivars with different isoflavonoid contents. In the present study, a functional genomic approach was used to identify the factor that regulates CHS8 expression and isoflavonoid synthesis. Candidate genes were cloned, and co-transfection assays were performed in Arabidopsis leaf protoplasts. The results showed that GmMYB176 can trans-activate the CHS8 promoter with maximum activity. Transient expression of GmMYB176 in soybean embryo protoplasts increased endogenous CHS8 transcript levels up to 169-fold after 48 h. GmMYB176 encodes an R1 MYB protein, and is expressed in soybean seed during maturation. Furthermore, GmMYB176 recognizes a 23 bp motif containing a TAGT(T/A)(A/T) sequence within the CHS8 promoter. A subcellular localization study confirmed nuclear localization of GmMYB176. A predicted pST binding site for 14-3-3 protein is required for subcellular localization of GmMYB176. RNAi silencing of GmMYB176 in hairy roots resulted in reduced levels of isoflavonoids, showing that GmMYB176 is necessary for isoflavonoid biosynthesis. However, over-expression of GmMYB176 was not sufficient to increase CHS8 transcript and isoflavonoid levels in hairy roots. We conclude that an R1 MYB transcription factor, GmMYB176, regulates CHS8 expression and isoflavonoid synthesis in soybean.

ATP binding cassette transporters couple ATP hydrolysis to the transmembrane transport of a diverse range of compounds. Members of the ATP binding cassette transporter superfamily are characterized by two membrane-integral domains that each contain 6 or more membrane spanning helices, but are otherwise poorly conserved, and two peripheral ATP binding cassette domains that display sequence conservation across the entire superfamily (1). In addition to the membrane complex, ATP binding cassette systems that catalyze nutrient uptake have primary receptors (binding proteins) that serve two functions: they provide a high affinity binding site for the transported molecule and they regulate the ATPase activity of the integral membrane complex.We are interested in the function of the primary receptors in the transport process. As a group, these proteins have been intensively studied by x-ray crystallography and other biophysical techniques (for a review, see Ref.2). They typically contain two domains separated by a hinge region; the substrate binds in the cleft between the two domains, and the protein undergoes a large conformational change, leading to closure of the cleft. With respect to the maltose transport system, domain closure in the binding protein is thought to be the first step toward molecular shape recognition by the membrane complex (3, 4), although it has been shown that both substrate-loaded and substrate-free binding proteins have a role in the transport cycle (5-8). The association and dissociation of the substrate, and attendant conformational changes in the binding protein (MBP), 1 may have direct effects on transport kinetics and regulation of ATP hydrolysis by MalFGK 2 . To investigate the role of binding protein affinity on the transport process, our goal was to engineer MBP molecules with greater affinity for maltose, without changing residues in either the maltose binding site or in regions thought to interact with MalFGK 2 .Crystal structures of MBP in both the closed and open conformations have been solved (9, 10), and they show that binding of maltose results in a large conformational change of the protein, bringing the two domains together such that the substrate is buried inside the cleft. In solution, unliganded MBP is in the open conformation (11); however, there is no obvious energetic barrier to closure of the ligand binding cleft, either in the hinge or in the interface surrounding the ligand binding site. Rather, an interface on the opposite side of the hinge from the ligand binding site appears to maintain the protein in an * This work was supported by Natural Sciences and Engineering Research Council Grant 21749-1999 (to B. H. S.); the macromolecular x-ray facility at the University of Western Ontario was financed with grants from the Canada Foundation for Innovation, Ontario Challenge Fund, and Western's Academic Development Fund; fluorescence and SPR studies were carried out at the University of Western Ontario Biomolecular Interactions and Conformations Facility, supported by a Mu...

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Metastatic disease is the principal cause of prostate-cancer-related mortality. Our ability to accurately recapitulate the spread of prostate cancer to bone - the most common site of metastasis - is critical to the development of novel metastasis-directed therapies. Several translational models of prostate cancer bone metastasis have been developed, including animal models, cell line injection models, 3D in vitro models, bone implant models, and patient-derived xenograft models. The use of these models has led to numerous advances in elucidating the molecular mechanisms of metastasis and innovations in targeted therapy. Despite this progress, current models are limited by a failure to holistically reproduce each individual element of the metastatic cascade in prostate cancer bone metastasis. In addition, factors such as accurate recapitulation of immunobiological events and improvements in tumour heterogeneity require further consideration. Knowledge gained from historical and currently used models will improve the development of next-generation models. An introspective appraisal of current preclinical models demonstrating bone metastases is warranted to narrow research focus, improve future translational modelling, and expedite the delivery of urgently needed metastasis-directed treatments.

The extracellular matrix polysaccharide hyaluronan (HA) plays a key role in both fibrotic and regenerative tissue repair. Accumulation of high molecular weight HA is typical of regenerative repair, which is associated with minimal inflammation and fibrosis, while fragmentation of HA is typical of postnatal wounds, which heal in the presence of inflammation and transient fibrosis. It is generally considered that HA oligosaccharides and fragments of a wide size range support these processes of adult, fibrotic wound repair yet the consequences of sized HA fragments/oligosaccharides to each repair stage is not well characterized. Here, we compared the effects of native HA, HA oligosaccharide mixtures and individual sizes (4–10mer oligosaccharides, 5 and, 40 kDa) of HA oligosaccharides and fragments, on fibroblast migration in scratch wound assays and on excisional skin wound repair in vivo. We confirm that 4–10mer mixtures significantly stimulated scratch wound repair and further report that only the 6 and 8mer oligosaccharides in this mixture are responsible for this effect. The HA 6mer promoted wound closure, accumulation of wound M1 and M2 macrophages and the M2 cytokine TGFβ1, but did not increase myofibroblast differentiation. The effect of 6mer HA on wound closure required both RHAMM and CD44 expression. In contrast, The 40 kDa HA fragment inhibited wound closure, increased the number of wound macrophages but had no effect on TGFβ1 accumulation or subsequent fibrosis. These results show that specific sizes of HA polymer have unique effects on postnatal wound repair. The ability of 6mer HA to promote wound closure and inflammation resolution without increased myofibroblast differentiation suggests that this HA oligosaccharide could be useful for treatment of delayed or inefficient wound repair where minimal fibrosis is advantageous.

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