Photoactivated Aluminium Phthalocyanine Drives Oxidative Stress and Apoptosis in Human Oesophageal Cancer Stem Cells

Photodynamic therapy (PDT), a light-based treatment strategy, has demonstrated efficiency against several cancers. However, the therapeutic effect of aluminium phthalocyanine chloride tetrasulfonate (AlPcS4Cl)-mediated PDT, which induces oxidative stress and potentiates apoptotic activity in oesophageal Cancer Stem Cells (CSCs), is limited. Therefore, this study examined the effects of AlPcS4Cl in promoting oxidative stress and apoptotic cell death in oesophageal CSCs.

The CSCs were isolated from HKESC-1 cells and were categorised into control and treatment groups. The CSCs treatment groups were exposed to AlPcS4Cl. Twenty-four hours after PDT, the effects of AlPcS4Cl on oesophageal CSCs in inhibiting cell growth, promoting oxidative stress, and cell death were evaluated. Cell viability was assessed using a viability assay. A cellular Reactive Oxygen Species (ROS) assay was used to determine the induction of oxidative stress. Rhodamine-123 flow cytometry analysis was performed to evaluate mitochondrial membrane potential. The Annexin V-FITC/PI assay was used to investigate the cell death mechanism, and a Caspase-Glo 3/7 luminescence assay was employed to assess caspase activities.

The results showed altered cell morphology, increased cytotoxicity, decreased cell viability, high ROS generation, impaired mitochondrial membrane, induced apoptosis, and increased caspase 3/7 activity in oesophageal CSCs treated with AlPcS4Cl-PDT compared to the control cells.

The finding implies that AlPcS4Cl-PDT promotes oxidative stress and apoptosis in oesophageal CSCs, supporting its application for the elimination of CSCs and as an effective anticancer agent.

This study demonstrates the promising use of AlPcS4Cl-PDT in eradicating oesophageal CSCs and improving prognosis.