The distribution of trace elements Ca, Fe, Cu and Zn and the determination of copper oxidation state in breast tumour tissue using μSRXRF and μXANES

Abstract

A micro beam synchrotron x-ray fluorescence (muSRXRF) technique has been used to determine the localization of metals in primary invasive ductal carcinoma of breast. Nine samples were examined, all of which were formalin fixed tissues arranged as micro arrays of 1.0 mm diameter and 10 microm thickness. Cu was the particular interest in this study although 2D maps of the elements Ca, Fe and Zn, which are also of physiological importance, are presented. The distribution of these metals was obtained at approximately 18 microm spatial resolution and compared with light transmission images of adjacent sections that were H and E stained to reveal the location of the cancer cell clusters. Correlations were found between these reference images and the elemental distributions indicating an increase in all element concentrations in the tumour regions of all samples, with the exception of Fe, which in some cases showed a reverse of this trend. On average over all samples the percentage difference from the normal tissue elemental concentrations are Ca approximately 67%, Cu approximately 64% and Zn approximately 145%. Micro x-ray absorption near edge spectroscopy (muXANES) was used to estimate the oxidation state of Cu in 19 normal and 17 tumour regions spread over five samples. The shape and the position of both normal and tumour regions suggest that they contain mixtures of copper ions with a significant fraction of Cu2+. However, the shape of the spectra does not exclude the presence of Cu+. Tumour regions were found to have a higher fraction of Cu+ compared to the normal samples.

Enhancing Tumor-Specific Uptake of the Anticancer Drug Cisplatin with a Copper Chelator

“…Indeed, the copper transporter Ctr1 was more highly expressed in cervical carcinoma of the HPV16/E 2 mice than in the wild-type cervix. Concordant with our observation is a recent demonstration using micro-beam synchrotron X-ray fluorescence that copper is concentrated in tumor regions of tissue specimens obtained from invasive ductal carcinoma of the breast (Farquharson et al, 2008). …”

Bioavailable copper modulates oxidative phosphorylation and growth of tumors

“…Second, in our study copper chelation did not increase ROS in tumors or invasiveness, consistent with the notion that complex IV is not a major site for ROS release (29). Third, cancers appear to have an increased need for copper compared with normal tissues (45,46), and we have observed increased levels of the copper transporter Ctr1 protein in mouse cervical carcinoma (9) and increased Ctr1 mRNA levels in islets undergoing tumorigenesis (Fig. S4).…”

Identification of the molecular mechanisms underlying the cytotoxic action of a potent platinum metallointercalator

“…Iron and copper are required by proliferating cancer cells during carcinogenesis [32,39,59,77] and high levels of iron and copper were found in certain tumour cells and tissues, including breast cancer cells [17,33]. As iron and copper metabolism is up-regulated in neoplastic tumours [29,39,41,44,47,59,62,65,72], 56MESS and other complexes in this class should be assessed, in combination with cisplatin, in the cancer models that have elevated iron and copper metabolism.…”