Phototoxicity of two positive-charged diaryl porphyrins in multicellular tumor spheroids.

Photodynamic therapy (PDT) is a clinically approved cancer treatment in which reactive oxygen species are formed only when three harmless components, a photosensitizer (PS), light and molecular oxygen, are present at the same time, leading to cell death. Most of the PSs were tested on monolayer cells, but differences between 2D cells and solid tumors significantly limit the value of in vitro PDT studies, whereas the use of 3D spheroid might be more suitable for drug development and preclinical drug testing for PDT. In a previous work we have shown that two positive-charged diaryl porphyrins (2 and 4) were more potent than the corresponding neutral molecules (1 and 3) on a panel of 2D-cultured cancer cell lines. In the present study the photodynamic effects of these molecules have been evaluated on HCT116 and MCF7 spheroids. Induction of apoptotic and necrotic cell death, and generation of reactive oxygen species (ROS) have been also evaluated, along with accumulation and localization of PSs into spheroids. Our findings indicate that 2 and 4 retained their phototoxic effects also in 3D spheroids; furthermore, they were more potent than 1 and 3 and as potent as Foscan (m-THPC), the most successful PS approved for clinical PDT of cancer, used as reference. Although further aspects of their mechanisms of action need to be addressed, our results strongly suggest a potential in vivo photodynamic application of 2 and 4, considering that spheroids represent a more realistic indicator of in vivo therapeutic efficacy than 2D cell lines.

Normal range of calcitonin in children measured by a chemiluminescent two-site immunometric assay.

Calcitonin (CT) assay is of considerable importance in the routine evaluation of thyroid nodules and for screening and follow-up of patients with medullary thyroid carcinoma and their relatives. Aim of this study was to assess the reference ranges for CT levels in healthy children and to evaluate possible differences in CT levels between sex and age. Serum CT levels were measured by a commercially available two-site chemiluminescence immunometric assay (sensitivity = 0.2 pg/ml). The ILMA recognizes the mature monomeric form of CT. We evaluated a cohort of 125 healthy children and compared these results with those from 98 healthy adult men and women. The ranges for human CT in children were <0.2-11.7 pg/ml and <0.2-17 pg/ml for female and male, respectively. No gender differences were observed in children population, though higher CT levels were observed in males. Serum CT levels did not correlate with age. Adult female had statistically significant lower CT levels than female children (p