Biomimetic Modeling of Copper Complexes: A Study of Enantioselective Catalytic Oxidation on D-(+)-Catechin and L-( − )-Epicatechin with Copper Complexes

The biomimetic catalytic oxidations of the dinuclear and trinuclear copper(II) complexes versus two catechols, namely, D-(+)-catechin and L-( − )-epicatechin to give the corresponding quinones are reported. The unstable quinones were trapped by the nucleophilic reagent, 3-methyl-2-benzothiazolinone hydrazone (MBTH), and have been calculated the molar absorptivities of the different quinones. The catalytic efficiency is moderate, as inferred by kinetic constants, but the complexes exhibit significant enantio-differentiating ability towards the catechols, albeit for the dinuclear complexes, this enantio-differentiating ability is lower. In all cases, the preferred enantiomeric substrate is D-(+)-catechin to respect the other catechol, because of the spatial disposition of this substrate

Discordance of Biomarker Expression Profile between Primary Breast Cancer and Synchronous Axillary Lymph Node Metastasis in Preoperative Core Needle Biopsy

Background: Breast cancer (BC) is a heterogeneous disease made up of clones with different metastatic potential. Intratumoral heterogeneity may cause metastases to show divergent biomarker expression, potentially affecting chemotherapy response. Methods: We investigated the immunohistochemical (IHC) and FISH profile of estrogen receptors (ER), progesterone (PR) receptors, Ki67, and HER2 in a series of BC-matched primary tumors (PTs) and axillary lymph node (ALN) metastases in pre-operative core needle biopsies (CNBs). Phenotypical findings were correlated to morphological features and their clinical implications. Results: Divergent expression between PTs and ALNs was found in 10% of the tumors, often involving multiple biomarkers (12/31, 39%). Most (52%) displayed significant differences in ER and PR staining. HER2 divergences were observed in almost three-quarters of the cases (23/31, 74%), with five (16%) switching from negativity to overexpression/amplification in ALNs. Roughly 90% of disparities reflected significant morphological differences between PTs and ALN metastases. Less than half of the discrepancies (12/31, 39%) modified pre/post-operative treatment options. Conclusions: We observed relevant discrepancies in biomarker expression between PTs and metastatic ALNs in a noteworthy proportion (10%) of preoperative BC CNBs, which were often able to influence therapies. Hence, our data suggest routine preoperative assessment of biomarkers in both PTs and ALNs in cases showing significant morphological differences

Stereoselective catalytic oxidations of biomimetic copper complexes with a chiral trinucleating ligand derived from 1,1-binaphthalene.

The new octadentate ligand R-(−)-N,N-dimethyl-N,N-bis{3-[bis(1-methyl-2-benzimidazolyl)amino]propyl}1,1- binaphthalenyl-2,2-diamine (L) was employed for the synthesis of dinuclear and trinuclear copper(II) complexes. Two terminal binding sites with tridentate aminobis(benzimidazole) linkages (A sites) and one central binding site with the bidentate diamino-binaphthalenyl residue (B site) are used by the ligand to bind divalent metal centres in the trinuclear complex [Cu3L][ClO4]6. Spectroscopic measurements suggest that in the dinuclear complex [Cu2L][ClO4]4 the copper ions are five-coordinated, with ligation by the aminobis(benzimidazole) residues, one of the tertiary amine donors of the diamino-binaphthalenyl moiety, and one water molecule. The complexes bind azide in the -1,3 fashion at low concentration and in the terminal mode at high concentration. The copper(II) complexes derived from L are catalytically active in the oxidation of 3,5-di-tert-butylcatechol (DTBC) by dioxygen. The oxidations are biphasic, with a fast initial stoichiometric phase corresponding to reduction of a pair of copper(II) centres and oxidation of DTBC to quinone, followed by the catalytic reaction, that follows substrate saturation behaviour. The complexes act as stereoselective catalysts in the biomimetic oxidations of the optically active catechol derivatives l- and d-Dopa and their methyl esters. In all the cases, the preferred enantiomeric substrate has the L configuration. This preference is dictated by the chirality of the binaphthalenyl residue