The influence of 5-aminolevulinic photodynamic therapy on colon cancer cell interleukin secretion in hypoxia-like condition in vitro.

Photodynamic therapy (PDT) becomes a method of personalized cancer treatment, based on the individual determination of cancer biomarkers. The aim of the study was to evaluate the influence of PDT with δ-aminolevulinic acid (ALA-PDT) used in sub-lethal dose on the interleukins secretion (IL-6, IL-8 and IL-10) by the residual colon cancer cells (CCC) under hypoxia-like conditions (addition of cobalt chloride- CoCl). CCC: SW480 and SW620 cells were incubated with ALA, CoCl and irradiated with red light. The cells viability was detected using MTT assay, LDH and apoptosis tests. Determination of interleukins was carried out using the Bio- Plex Assay Pro kit on the Bio- Plex Suspension Array System. After ALA-PDT we found no change in the IL-6 level secreted by SW480 cells, but decrease of IL-6, IL-10 secretion by SW620 cells, an increase in the IL-8 secreted by both cells lines. The levels of IL-6, IL-8 and IL-10 secreted by more aggressive SW620 cells were higher than released by SW480 cells. We concluded, that PDT not only effectively destroy malignant tissue, but also used in sub-lethal dose can develops its anticancer activity through the reduction of IL-6 and IL-10 secretion. On the other hand, we reveal an unfavorable PDT effect, connected with increase of IL-8 secretion by both treated colon cancer cell lines, which implicates the use of adjuvant immunotherapy against IL-8, as a part of individualized colon cancer therapy.