Effectiveness of zinc-phthalocyanine and hypericin in inducing cell death in human breast cancer cells (mcf-7) using low intensity laser irradiation (lili)

Abstract

M.Tech. (Biomedical Technology)The uncontrolled growth of cells in the body is often associated with cancer. It constitutes a major health problem and is one of the leading causes of death in the world. Cancers of the lung, breast, colon/rectum and prostate are no longer only associated with developed countries but are the most common occurring cancers worldwide. Breast cancer is the leading cancer faced by women in South Africa as well as in the world. Conventional cancer therapies often result in uncertain outcomes with numerous side effects and may be associated with limited therapeutic advantage. This has led to the development of safer and better treatment regimes with improved therapeutic outcomes. Photodynamic therapy (PDT) is a treatment used for a wide range of conditions, including cancer. This treatment utilises a photosensitiser (PS), a light activated chemotherapeutic agent, and light of a specific wavelength and power density. It is based on the selective tumour localisation of the PS and the ability to generate high levels of reactive oxygen species (ROS) in the presence of light. The generation of ROS causes permanent damage to the tumour cells resulting in cancer cell death. The distinctive criteria when comparing different PDT modalities is the choice of PS as the treatment outcomes are greatly influenced by the light dependent properties of the chemotherapeutic agent. Phthalocyanines are second generation PSs used in PDT. Effects of members of this PS family have been studied and they exhibited good photosensitising properties including lack of cytotoxicity in the absence of light, extended retention times in the tumour and high triplet lifetime of singlet oxygen species