Anticancer effects elicited by combination of Rubus extract with phthalocyanine photosensitiser on MCF-7 human breast cancer cells

Background: Photodynamic therapy (PDT) is a novel approach for the treatment of cancer and other related diseases. Breast cancer remains the most common cause of cancer-related death in women. This study was carried out to investigate the photosensitizing capacity of Rubus fairholmianus root acetone extract (RFRA) in vitro.

Methods: RFRA was coupled with phthalocyanine photosensitizer to enhance the therapeutic properties on MCF-7 breast cancer cells. Comparatively low dose photosensitizer (PS) and Rubus extract have been used for the conjugation as it induces cell death at low doses. The diode laser of wavelength 680 nm and 5, 10 and 15 J/cm2 fluencies have been used for PDT experiments/laser irradiation. MCF-7 cells were exposed to Rubus extract and conjugated Rubus-PS for 24 h and analysed the alterations in cell morphology, proliferation, cytotoxicity and apoptosis induction.

Results: The PDT-treated cells displayed substantial features of apoptotic cell death by changes in morphology with a reduction in cell number, development of apoptotic bodies and cell detachment from culture plates. Cellular viability (51.25% for RFRA-PS at 15 J/cm2) and Adenosine 5'-triphosphate (ATP) proliferation of treated cells reduced significantly and the cytotoxicity increased in lactate dehydrogenase (LDH) assay. The Annexin V/PI double staining supports the caspase 3/7 activities by the increased apoptotic cells population and the increased levels of cytochrome c.

Conclusion: Our results show that the phototoxic properties of RFRA and photosensitizer may be through the caspase-mediated apoptosis and it can be summarised that Rubus may be a potent anticancer plant with phototoxic effects on breast cancer cells.