Anticancer Laccases: A Review

Laccases are copper containing enzymes that are found primarily in the basidiomycetes group of fungi, known as white-rot fungi and mainly involved wood decay. Additionally, laccases have been detected in other organisms like plants, insects and bacteria. Laccases oxidize phenolic substrates and simultaneously reduce oxygen to water. The fact that water is produced as a by-product is a feat unlike no other in the chemical and biotechnological industry; consequently laccases have been put to many uses in these fields. Very recently, laccases have found a potential use in the field of therapeutics, particularly against cancer. The first record of antiproliferative activity of laccase dates back to 2006. Then from 2010 to 2014, eight novel laccases from eight different basidiomycetes were shown to have anti-proliferative activities primarily against breast cancer and liver carcinoma cell lines. However, the mechanism of this activity still remains a mystery. Several laccases have displayed the ability to degrade estrogens because of which they are used in environmental pollution treatment strategies. Estrogens, a group of steroidal hormones consists of three primary hormones namely estrone, 17β-estradiol and estriol. 17β-estradiol is the most potent of all estrogens and its role in the growth and development of breast cancer is well established. In this review, we describe the structural properties, activities and sequence similarities of laccases and discuss their activity against breast cancer cells with the possible involvement of 17β-estradiol in this mechanism.