Faculty Bibliography

Recent studies show that cadherins and catenins are hormonally regulated and carry out physiological roles during mammary development but have pathological effects when deregulated. E-cadherin expression is irreversibly lost in invasive lobular breast cancer (ILC). Animal models of ILC provide mechanistic insight, confirming that E-cadherin serves as both a tumor suppressor and an invasion suppressor in ILC. Ductal breast cancer involves complex, reversible, epigenetic modulation of multiple cadherins. Transcriptional regulators of E-cadherin have been identified that induce epithelial-to-mesenchymal transitions. Catenins are lost or mislocalized in tumors lacking cadherins. However, beta-catenin signaling is upregulated by numerous pathways in >50% of breast tumors and animal models suggest its oncogenic function in breast relates to its role in mammary progenitor cell expansion

Egg infertility remains the greatest challenge in the treatment of the infertile couple. As women increasingly delay attempts at childbearing, egg infertility has become more prevalent. Attempts to overcome egg infertility by superovulation and in vitro fertilization have produced an epidemic of multiple gestations, itself a major public health concern. The pathophysiology of egg infertility arises from chromosomal nondisjunction. Cytogenetic analyses of polar bodies and/or blastomeres currently provide the most powerful predictors of egg infertility. Approaches that label all chromosomes (spectral karyotyping and comparative genomic hybridization), or identify predisposition to aneuploidy (spindle imaging, telomere length measurement) are on the horizon. For the foreseeable future, the treatment of egg infertility will be limited to egg donation for severe cases and transfer of the most viable embryos for milder cases. Oocyte reconstitution not only lacks evidence of clinical efficacy, but also biological credibility, given that growing evidence supports the primacy of chromosomes themselves in meiotic nondisjunction

Clinical pregnancy rate (CPR) and implantation rate (IR) in 1,177 patients who had 1,788 fresh, nondonor, nonPGD IVF cycles were highest in cycle 1, significantly declined in cycle 2, and reached a plateau for cycles 3-5 at a rate lower than in cycle 2. In patients >38 years of age CPR and IR in cycles 1 and 2 were significantly lower than in younger patients, but there was no decline in CPR or IR with advancing IVF attempts

The macrophage scavenger receptor CD36 plays a key role in the initiation of atherosclerosis through its ability to bind to and internalize oxidized low-density lipoproteins (oxLDL). Prompted by recent findings that the CD36 receptor also recognizes amyloid fibrils formed by beta-amyloid and apolipoprotein C-II, we investigated whether the oxidation of low-density lipoproteins (LDL) generates characteristic amyloid-like structures and whether these structures serve as CD36 ligands. Our studies demonstrate that LDL oxidized by copper ions, 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH), or ozone react with the diagnostic amyloid dyes thioflavin T and Congo Red and bind to serum amyloid P component (SAP), a universal constituent of physiological amyloid deposits. X-ray powder diffraction patterns for native LDL show a diffuse powder diffraction ring with maximum intensity corresponding to an atomic spacing of approximately 4.7 A, consistent with the spacing between beta-strands in a beta-sheet. Ozone treatment of LDL generates an additional diffuse powder diffraction ring with maximum intensity indicating a spacing of approximately 9.8 A. This distance is consistent with the presence of cross-beta-structure, a defining characteristic of amyloid. Evidence that these cross-beta-amyloid structures in oxLDL are recognized by macrophages is provided by the observation that SAP strongly inhibits the association and internalization of (125)I-labeled copper-oxidized LDL by peritoneal macrophages. The ability of SAP to bind to amyloid-like structures in oxLDL and prevent lipid uptake by macrophages highlights the potential importance of these structures and suggests an important preventative role for SAP in foam cell formation and early-stage atherosclerosis

The aldose reductase pathway has been demonstrated to be a key component of myocardial ischemia reperfusion injury. Previously, we demonstrated that increased lactate/pyruvate ratio, a measure of cytosolic NADH/NAD+, is an important change that drives the metabolic cascade mediating ischemic injury. This study investigated signaling mechanisms by which the aldose reductase pathway mediates myocardial ischemic injury. Specifically, the influence of the aldose reductase pathway flux on JAK-STAT signaling was examined in perfused hearts. Induction of global ischemia in rats resulted in JAK2 activation followed by STAT5 activation. Pharmacological inhibition of aldose reductase or sorbitol dehydrogenase blocked JAK2 and STAT5 activation and was associated with lower lactate/pyruvate ratio and lower protein kinase C activity. Niacin, known to lower cytosolic NADH/NAD+ ratio independent of the aldose reductase pathway inhibition, also blocked JAK2 and STAT5 activation. Inhibition of protein kinase C also blocked JAK2 and STAT5 activation. Transgenic mice overexpressing human aldose reductase exhibited increased JAK2 and STAT5 activation. Pharmacological inhibition of JAK2 reduced ischemic injury and improved functional recovery similar to that observed in aldose reductase pathway inhibited mice hearts. These data, for the first time, demonstrate JAK-STAT signaling by the aldose reductase pathway in ischemic hearts and is, in part, due to changes in cytosolic redox state

PURPOSE: The rat has been a cost-effective model for the evaluation of bladder development, cancer and stromal-epithelial interactions. Serial cultivation of rat urothelium has been difficult. We developed a reliable protocol for the harvest, serial cultivation and cryopreservation of rat urothelium. We investigated the differentiation markers of in vivo bladder urothelium compared with cells reconstituted onto an acellular bladder matrix. MATERIALS AND METHODS: Epithelial harvest techniques using trypsin and collagenase were compared. Medium and conditions were optimized for serial culture and growth characteristics were calculated. Cultured cells were cryopreserved, and then recovered and grown on acellular bladder matrices. Morphology and markers of differentiation were compared between normal bladder and engineered grafts using scanning electron microscopy (SEM) and immunohistochemistry. RESULTS: Atraumatic enzymatic removal of urothelium with trypsin yielded more cells with greater viability than collagenase. Cells could be reliably grown beyond 10 passages using fibroblast conditioned medium and a 3T3 feeder layer during initial passages. Cryopreserved cells were successfully recovered and incorporated onto acellular matrices. Immunostaining and SEM of engineered grafts demonstrated early markers of differentiation, such as surface microvilli and cytokeratin 17, on polygonal cells with typical tight junctions. CONCLUSIONS: Rat urothelium can be reliably grown using fibroblast conditioned medium and a 3T3 feeder layer during primary culture. Serially passaged cells can survive cryopreservation and they are able to reconstitute epithelium on an acellular bladder matrix. Cells that are incorporated into the matrix express markers of early differentiation and demonstrate typical morphological characteristics by SEM. These culture techniques and this in vitro organoid model should facilitate the use of rat urothelium

We report the generation of a chimeric monoclonal antibody (ch806) with specificity for an epitope on the epidermal growth factor receptor (EGFR) that is different from that targeted by all other anti-EGFR therapies. Ch806 antibody is reactive to both de2-7 and overexpressed wild-type (wt) EGFR but not native EGFR expressed in normal tissues at physiological levels. Ch806 was stably expressed in CHO (DHFR -/-) cells and purified for subsequent characterisation and validated for use in preliminary immunotherapy investigations. Ch806 retained the antigen binding specificity and affinity of the murine parental antibody. Furthermore, ch806 displayed enhanced antibody-dependent cellular cytotoxicity against target cells expressing the 806 antigen in the presence of human effector cells. Ch806 was successfully radiolabelled with both iodine-125 and indium-111 without loss of antigen binding affinity or specificity. The radioimmunoconjugates were stable in the presence of human serum at 37 degrees C for up to 9 days and displayed a terminal half-life (T(1/2beta)) of approximately 78 h in nude mice. Biodistribution studies undertaken in BALB/c nude mice bearing de2-7 EGFR-expressing or amplified EGFR-expressing xenografts revealed that (125)I-labelled ch806 failed to display any significant tumour retention. However, specific and prolonged tumour localisation of (111)In-labelled ch806 was demonstrated with uptake of 31%ID g(-1) and a tumour to blood ratio of 5 : 1 observed at 7 days postinjection. In vivo therapy studies with ch806 demonstrated significant antitumour effects on established de2-7 EGFR xenografts in BALB/c nude mice compared to control, and both murine 806 and the anti-EGFR 528 antibodies. These results support a potential therapeutic role of ch806 in the treatment of suitable EGFR-expressing tumours, and warrants further investigation of the potential of ch806 as a therapeutic agent