The mechanism and influencing factors on photodynamic purging of leukemia cells

Abstract

The paper compared the response of HL60 cells with peripheral blood mononuclear cell (PBMC) after 5-ALA PDT for different periods of time and then followed by irradiating with different wavebands for different fluences. The results of parameter experiments were obtained: 1 × 105/mL HL60 cell was incubated with 1 mmol/L ALA in dark for 4 h and the maximum fluorescence of PpIX level appeared; then irradiated with 410 nm (4 mW/cm2) for 14.4 J/cm2 and maximum photodamage to membrane and mitochondrial function of HL60 cell resulted. Analyzed the experimental results of references, we got that the effect of photodynamic purging of leukemia cells may be modulated by the leukemia cell type; the photosensitizer's type, dose, and its location point; the incubation time and condition; the light wavelength and its dosage. If the light is delivered at a high rate, significant heating of a molecule and its surrounding may take place. A too low dosage has no effect at all or will result in high relapse rate due to the presence of cancer cells. The wavelength and intensity of light required to carry out photopurging is determined by the absorption properties of the photosensitizer. The light dose actually received by the photosensitizer and tissue may be higher or lower depending on the manner of irradiation.