{"id":1265,"date":"2019-08-02T19:08:27","date_gmt":"2019-08-02T11:08:27","guid":{"rendered":"http:\/\/www.bioactivescreeninglibrary.com\/?p=1265"},"modified":"2022-01-07T10:54:00","modified_gmt":"2022-01-07T02:54:00","slug":"development-solid-tumours-mice-injected-subcutaneously-human-ovarian-cancer-cell-line","status":"publish","type":"post","link":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/2019\/08\/02\/development-solid-tumours-mice-injected-subcutaneously-human-ovarian-cancer-cell-line\/","title":{"rendered":"Development of solid tumours in mice injected subcutaneously with a human ovarian cancer cell line"},"content":{"rendered":"

Increased the median survival time of mice in a human ovarian ascites model. In this communication we present biochemical, biophysical and structural characterization of 9a in its complexes with XIAP-BIR3, XIAP-BIR2BIR3 and cIAP1-BIR3. In particular, we report data on compound 9a binding to different BIR domains through analytical gel filtration and small angle X-ray scattering. Moreover, we present the crystal structures of cIAP1-BIR3 and XIAP-BIR3 domains in the presence of 9a, describing the molecular details of divalent Smac-mimetic recognition. Taken together, all the experimental evidences here reported suggest that 9a is one of the most powerful divalent Smac-mimetics known to date; the structural analysis of its recognition patterns, here presented, is the basis for further optimization in terms of target affinity and bioavailability. Compound 9a is a tail-tail homodimeric divalent Smac-mimetic that was rationally designed, together with nineteen other divalent compounds, to study how bifunctional inhibitors can bind and distinguish between XIAPand cIAPs-BIR2BIR3 domains. Among these, 9a showed prominent binding activity to BIR3 domains of XIAP and cIAPs, and to XIAP-BIR2BIR3, low cytotoxicity in two different cell lines, and the capability to induce activation of caspases and apoptosis. Moreover, the divalent compound proved effective in in vivo TH-302<\/a> treatments, after intraperitoneal daily administration, in two human IGROV1 ovarian cancer models, showing reduction of subcutaneous tumor growth in nude mice, and increase of the median survival time of mice in ascites model. Binding of the divalent compound to XIAP-BIR3 results in a crystal packing that differs from that observed in the crystal structures of the XIAP-BIR3 complexes with monovalent Smacmimetic compounds known to date. Notably, the crystal lattice packing is also different from that observed for XIAP-BIR3 in complex with the divalent compound-3, whose crystal asymmetric unit hosts eight BIR3 molecules and eight compound-3 molecules, each of which has one inhibitory head bound to BIR3 and the other devoid of any contact to the protein. Comparative SAXS analysis of XIAP-BIR2BIR3 shows that the construct in the presence of the inhibitor adopts a more compact global conformation, likely induced by 9a simultaneous binding to both BIR domains. However, ensemble analysis of free XIAP-BIR2BIR3 shows that a Nilotinib<\/a> majority of the molecules adopt a compact conformation, suggesting that the two domains are transiently interacting even in the absence of 9a. Such result is also supported by a molecular dynamics simulation of XIAPBIR2BIR3 showing the conservation of an inter-domain interaction surface similar to that observed for XIAP-BIR3\/BIR3\/9a crystallographic dimer. A high resolution model of XIAP-BIR2BIR3\/9a complex using the domain crystal structures that nicely fits SAXS data can be obtained by slightly relaxing the shape of the XIAP-BIR3\/9a crystallographic dimer. In fact, a small separation of the two domains and the addition of the missing part of the structure lead to a much improved agreement with the SAXS data. In this simulated model, 9a maintains a right handed helical conformation, but with a pitch that is intermediate relative to both cIAP1-BIR3 and XIAP-BIR3. The SAXS experimental evidence of the presence of a transient interaction between XIAPBIR2BIR3, even when 9a is absent, indicates that the inhibitor may shift a preexisting equilibrium between open and closed.<\/p>\n","protected":false},"excerpt":{"rendered":"

Increased the median survival time of mice in a human ovarian ascites model. In this communication we present biochemical, biophysical and structural characterization of 9a in its complexes with XIAP-BIR3, XIAP-BIR2BIR3 and cIAP1-BIR3. In particular, we report data on compound 9a binding to different BIR domains through analytical gel filtration and small angle X-ray scattering. … Continue reading “Development of solid tumours in mice injected subcutaneously with a human ovarian cancer cell line”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/posts\/1265"}],"collection":[{"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/comments?post=1265"}],"version-history":[{"count":1,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/posts\/1265\/revisions"}],"predecessor-version":[{"id":1266,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/posts\/1265\/revisions\/1266"}],"wp:attachment":[{"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/media?parent=1265"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/categories?post=1265"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.bioactivescreeninglibrary.com\/index.php\/wp-json\/wp\/v2\/tags?post=1265"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}