Photosoft efficiently destroys ovarian cancer cells in vitro

  • Invion and Hudson Institute of Medical Research are collaborating on R&D projects for the PhotosoftTM technology as a treatment of a range of cancers
  • PhotosoftTM characterisation studies have been completed in multiple ovarian cancer cell lines
  • PhotosoftTM caused efficient and highly effective cancer cell destruction in vitro

Melbourne, Australia, 5 July 2018: Invion Limited (ASX: IVX, “Invion” or “Company”) is pleased to announce that initial characterisation of the novel chlorophyll based photodynamic therapy, PhotosoftTM in ovarian cancer has been completed under its Research & Development Alliance Agreement with leading Australian medical research institute, Hudson Institute of Medical Research (“Hudson Institute”).

Spectral characteristics, cellular uptake and clearance, intracellular localisation, dark and photo-toxicity were investigated in multiple ovarian cancer cell lines (human and murine) in both 2D and 3D organoid culture in vitro. PhotosoftTM caused efficient and highly effective cancer cell destruction in vitro, with 100% cell death achieved in a matter of minutes following light activation.

In the absence of light activation, PhotosoftTM was completely non-toxic to cells – highlighting its potential for clinical application without inducing non-specific phototoxicity, a major impediment experienced in the clinical application of other photosensitiser compounds.

Photodynamic Therapy (PDT), combining a photo-sensitising compound and light to generate destructive reactive oxygen species, is an effective strategy for tumour tissue ablation. The efficiency of a photosensitiser is one of the main factors for determining its feasibility as a Photodynamic Therapy. Whilst several photosensitisers are clinically approved, some have undesirable properties including extreme photosensitivity, poor water solubility and inadequate selectivity, limiting their clinical application.

Dr Andrew Stephens, Group Head of the Ovarian Cancer Biomarkers Research Group at Hudson Institute said, “The Photosoft characterisation studies demonstrate that PhotosoftTM efficiently produces reactive oxygen species to destroy tumour cells in vitro, and that modulation of light energy can be used to control the mechanism of induced cell death.”

Managing Director and Chief Executive Officer, Dr Greg Collier, said “Ovarian cancers have a greater than 70% 5-year mortality rate, and patients almost universally develop recurrent, chemo-resistant disease. New therapies are urgently needed and we are very pleased with this early progress under our R&D Alliance Agreement with Hudson Institute. This data lays the groundwork for ongoing preclinical trials of the PhotosoftTM technology as an indication for chemo-resistant, solid ovarian tumours.”

Further results of these studies will be presented in September 2018 at a major international conference.

About the studies

The spectral characteristics and production of reactive oxygen species (ROS) by PhotosoftTM were examined using in vitro assays. Cellular uptake and clearance were monitored using fluorescence in multiple ovarian cancer cell lines (2D and 3D), with sub-cellular localization determined using specific organelle staining (Endoplasmic Reticulum (ER), Golgi, lysosomes, mitochondria). Cell death and IC90 were determined following exposure to red light. The mechanism of induced cell death was determined using antibody arrays.

PhotosoftTM efficiently produced ROS following illumination in vitro, and uptake into ovarian cancer cells was time and concentration dependent. In the absence of activation, PhotosoftTM remained non-toxic even at high concentrations; once activated Photosoft caused rapid cancer cell death dependent on time, concentration and light energy.

Moreover, PhotosoftTM effectively penetrated and induced cell death in 3D spheroids, suggesting its suitability for ablation of established, solid tumours.

About Photodynamic Therapy (PDT)

Invion is developing PhotosoftTM technology as an improved next generation Photodynamic Therapy. PDT uses non-toxic photosensitisers and visible light in combination with oxygen to produce cytotoxic-reactive oxygen that kills malignant cells, shuts down tumours and stimulates the immune system. In contrast to surgery, or radiotherapy and chemotherapy which are mostly immunosuppressive, PDT causes acute inflammation, expression of heat-shock proteins, and invasion and infiltration of a tumour by leukocytes.