Can metal replacement increase the antitumor activity of azurin? (in vitro study)

Abstract

Azurin is a member of blue-copper proteins family which induces apoptosis in cancer cells. In the present work, azurin (Az) has been modified via replacement of copper at active site with cobalt and nickel. FTIR revealed that its secondary structure is practically indistinguishable from that of its derivatives. UV spectroscopy and DSC results revealed that native form of Az is more stable than Co-and Ni forms. SRB was used to elucidate their possible anti-tumor effect on cancer cell lines from breast and colon cells (MCF-7 and HCT116, respectively). To our best knowledge, this is the first time metal replacement of Az has been used with cell line. It appears that this process is the predominant reason for the effectiveness of Az. Experimental results showed that the anti-tumor activity of Cu-and Co Az (at concentration ≤ 25 µg/L) is higher for colon-relative to breast cells, while that for Ni-Az is higher for both cells (at low concentration, 5 µg/L). Hence, according to our findings it was revealed that Ni-Az form has the most extensive anti-antitumor effect on breast-and colon cancer cells. This highlights that Ni may be bona fide copper ion impersonator in vivo.