PHOTOTHERAPY AGAINST CANCER AND EFFECTS OF GLYCATED CHITOSAN ON SOMATIC CELLS

Abstract

Immunoadjuvant is a molecule or solution that enhances the immune response to a stimuli or vaccine. N-dihydrogalactochitosan (glycated chitosan, GC) is an immunoadjuvant used in combination with photothermal therapy to treat late-stage, metastatic cancers. After tumor cells release damage-associated molecular patterns (DAMPs) from laser irradiation, GC is uptaken by antigen-presenting cells (APCs) at the treatment site. These APCs can differentiate into their inflammatory state and then activate the adaptive immune system. This chain reaction will then eliminate the residual tumor, as well as metastatic cancer cells. GC can also be combined with antigens in an intra-nasal vaccine formulation against respiratory infections. The use of GC in the formulation promotes the number of recruited T cells and IgA at the delivery site. The reaction of immune cells to GC is well studied but its direct effects on cancer and epithelial cells have not been fully explored. In this study, we investigated the potential effect of GC on nasal epithelial cells and on the cancer cells in the anti-viral and anti-tumor contexts. We used viability assays, confocal imaging, and flow cytometry to determine GC’s toxicity on different cell lines, epithelial cells’ intake of GC, and activations induced by GC. Understanding GC’s interaction with non-immune cells can advance our knowledge of GC’s mechanism and potentially find novel applications for cancer therapies and vaccinations. Chen lab combined the use of GC with photothermal therapy. However, photothermal is not the only form of therapy using laser power. Photodynamic therapy is another potential approach. It generates reactive oxygen species (ROS) using the energy of the laser accumulated by a photosensitizer (PS). These ROS then provoke the death of the cancer cells. Photochemical internalization combined encapsulated cancer toxic molecules with the use of a PS to deliver these toxic compounds in the cytosol of the cancer cells. We will also review the current treatment modalities used for cancer patients by clinicians and compare their efficacy.