title: Levofolene modulates apoptosis induced by 5-fluorouracil through autophagy inhibition: clinical and occupational implications.
abstract: 5-Fluorouracil (5-FU), often used in combination with levofolene (LF), can induce, as an important side effect, the hand-foot syndrome (HFS) due to toxicity on keratinocytes. This can also damage workers involved in its handling. In the present study, we investigated the mechanisms of the toxicity induced by 5-FU alone or together with LF on human keratinocytes in culture. We found that the two drugs, as expected, had potentiating activity on keratinocyte growth inhibition and that this effect was mediated by induction of apoptosis. In our experimental model, an increased autophagic vacuole accumulation was observed in keratinocytes treated with 5-FU as a significant increase of the monodansylcadaverine (MDC) labeling (marker of late autophagy vacuoles) was recorded. However, the synergism of 5-FU with LF on apoptotic occurrence was not paralleled by a similar increase in autophagic vacuoles at 72 h suggesting an antagonistic effect of LF on autophagy elicited by 5-FU. Differential effects on reactive oxygen species (ROS) elevation in cells treated with 5-FU alone or the combination between 5-FU and LF were also observed. 5-FU induced a time-dependent increase of both O2- and lipid peroxidation while the combination of 5-FU and LF caused a stronger intracellular O2- increase only at 24 h while at 48 and 72 h its effect was lower when compared with that one of 5-FU alone. On the other hand, the addition of LF to 5-FU caused a stronger increase of lipid peroxidation at 48 and 72 h, but its effects were significantly lower at 24 h. These results suggest for the first time that LF potentiates the cytotoxicity of 5-FU on keratinocytes likely through the antagonism on autophagy escape pathway and consequent apoptosis potentiation.
authors.affiliation: Department of Experimental Medicine, Section of Occupational Medicine, Second University of Naples, Naples, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Lamberti
authors.affiliation: Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Porto
authors.affiliation: Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Zappavigna
authors.affiliation: Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Stiuso
authors.affiliation: Section of Biotechnology and Medical Histology, Second University of Naples, Naples, Italy.
authors.forename: Virginia
authors.initials: V
authors.lastname: Tirino
authors.affiliation: Section of Biotechnology and Medical Histology, Second University of Naples, Naples, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Desiderio
authors.affiliation: Section of Biotechnology and Medical Histology, Second University of Naples, Naples, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Mele
authors.affiliation: Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Caraglia
mesh_terms: D000931:Antidotes / Q000494:pharmacology*; D000964:Antimetabolites, Antineoplastic / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D002460:Cell Line; D004338:Drug Combinations; D004357:Drug Synergism; D005434:Flow Cytometry; D005472:Fluorouracil / Q000633:toxicity*; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000473:pathology; D058766:Levoleucovorin / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000931:Antidotes; D000964:Antimetabolites, Antineoplastic; D004338:Drug Combinations; D017382:Reactive Oxygen Species; D058766:Levoleucovorin; D005472:Fluorouracil