Biomarkers of Skin Graft Healing in Venous Leg Ulcers.

There is a need for biomarkers that predict the success of transplantation of venous leg ulcers (with autologous split-thickness skin grafts). The primary objective of this exploratory study was to investigate the association between split-thickness skin graft healing in venous leg ulcers and candidate wound fluid biomarkers representing inflammatory cell and endogenous proteinase activities, and bioactivity. A secondary objective was to compare biomarker levels of the 17 venous leg ulcers with sterile split-thickness skin graft donor-site wounds in another 10 patients with venous leg ulcers. Wound fluids were collected for 24 h using a validated method. The concentration of preoperative matrix metalloproteinase-9 in wound fluid was higher in venous leg ulcers showing good healing (n = 10) than in venous leg ulcers showing poor healing (n = 7) 12 weeks after transplantation with meshed split-thickness skin grafts. The diagnostic value of matrix metalloproteinase-9 was good according to receiver-operating characteristic curve analysis. Matrix metalloproteinase activity in wound fluids from split-thickness skin graft donor-site wounds increased as a function of time and healing, but was still lower than matrix metalloproteinase activity in venous leg ulcer wound fluids, which showed increased levels of most biomarkers except for matrix metalloproteinase-9 and matrix metalloproteinase-2. In conclusion, wound fluid matrix metalloproteinase-9 concentration is a potential predictive biomarker of split-thickness skin graft healing in venous leg ulcers.

Cell membrane permeability and defective G2/M block as factors potentially contributing to increased cell chemosensitivity. SeAx cell line as an example.

BACKGROUND: Immortalized mammalian cell lines are a valuable research tool, though they represent a highly simplified model. Due to accumulated mutations they may not reflect characteristics of the disease or even the tissue they derive from. OBJECTIVE: We aim to pinpoint factors distinguishing SeAx cells from two other cutaneous T-cell lymphoma (CTCL) cell lines, namely Hut78 and MyLa2000. Of note, these factors may influence cell sensitivity in an unspecific way and therefore should be taken under consideration. METHODS: We evaluated transcriptional levels of drug transporters across cell lines, cell membrane permeability, functionality of pathways related to DNA damage response and activation of G2/M block. RESULTS: Analysis of the transcriptional levels of genes coding drug efflux pumps indicated that they are not consistently down-regulated in SeAx. However, we noted that SeAx cell membrane is markedly more permeable than Hut78 and MyLa2000, which may contribute to increased chemosensitivity in an unspecific way.Moreover, though DNA damage response seemed to be at least partly functional in SeAx cells, they fail to activate G2/M block in response to psoralen + UVA treatment. Any DNA damage should be repaired before cells enter mitosis, in order to uphold genome integrity. Thus, a defective cell cycle block may contribute to cell sensitivity. CONCLUSIONS: We believe that factors such as increased membrane permeability or defective cell cycle block should be accounted for when comparing sensitivity of cell line panels to chemotherapeutics of interest. It is worth to exclude a simple, indiscriminative mechanisms of cell resistance or sensitivity before attempting comparisons. Cell lines that are indiscriminately sensitive to a broad range of chemicals may contribute to overestimating the cytotoxic potential of tested compounds if used in cytotoxicity studies.

Late type apoptosis and apoptosis free lethal effect of quercetin in human melanoma.

No satisfactory treatment is currently available for metastatic malignant melanoma. Recently, the flavonoid quercetin was suggested as a potential treatment due to its anti-tumorogenic properties. Some of these properties appeared to correspond to those published for UVB irradiation. To determine quercetin's long-term effects, type of apoptosis, and shared properties with UVB, we exposed Mel-Juso, M14, and G361 human melanoma cell-lines to a large range of quercetin or UVB doses, 20-400 microm and 25-1000 mJ/cm2 respectively. Apoptosis was measured for 4 consecutive d by flow cytometry and cell viability was studied by colony-forming assay. Quercetin decreased cell viability level in a dose-dependent manner to almost zero at 100 microm. Up to this concentration, it did not induce significant apoptosis nor did it decrease the survival-fractions below 90% during a 4 d follow-up. The data suggest that Quercetin is lethal to melanoma cells at concentrations that do not activate apoptosis during the first 4 d post-exposure and that quercetin's effects extend beyond the period of direct contact. Both quercetin and UVB induced late-type apoptosis at the upper range of the tested doses, but they do not appear to share all the pathways that they activate. Finally, this paper provides novel data showing that quercetin causes two different lethal effects on human melanoma cells, suggesting the activation of at least two different dose-depended mechanisms.