High Dosage Lithium Treatment Induces DNA Damage and p57Kip2 Decrease

Abstract

Lithium salt is the first-line therapeutic option for bipolar disorder and has been proposed as a potential antitumoral drug. The effects of LiCl treatment were investigated in SH-SY5Y, a human neuroblastoma cell line and an in vitro model of dopaminergic neuronal differentiation. LiCl, at the dosage used in psychiatric treatment, does not affect cell proliferation, while at higher doses it delays the SH-SY5Y cell division cycle and for prolonged usage reduces cell viability. Moreover, the ion treatment affects DNA integrity as demonstrated by accumulation of p53 and γH2AX (the phosphorylated form of H2AX histone), two important markers of genome damage. p57Kip2, a CIP/Kip protein, is required for proper neuronal maturation and represents a main factor of response to stress including genotoxicity. We evaluated the effect of lithium on p57Kip2 levels. Unexpectedly, we found that lithium downregulates the level of p57Kip2 in a dose-dependent manner, mainly acting at the transcriptional level. A number of different approaches, mostly based on p57Kip2 content handling, confirmed that the CKI/Kip reduction plays a key role in the DNA damage activated by lithium and suggests the unanticipated view that p57Kip2 might be involved in DNA double-strand break responses. In conclusion, our study identified novel roles for p57Kip2 in the molecular mechanism of lithium at high concentration and, more in general, in the process of DNA repair.

Regulation of p27Kip1 and p57Kip2 Functions by Natural Polyphenols

“…In the same way, silencing of CDKN1C determined the suppression of the apoptosis mediated by p73 followed to cisplatin treatment in lung and colorectal cancer cell lines [116]. Interestingly, we recently reported the involvement of p57 in campthotecin-induced topoisomerase inhibition and consequent DNA Double Strand break damage response [117]. However, depending on the cell model, the induction of p57 by anti-cancer drugs might be seen as a resistance factor to the treatment.…”

A cancer‐associated CDKN1B mutation induces p27 phosphorylation on a novel residue: a new mechanism for tumor suppressor loss‐of‐function

“…Whole‐cell extracts were obtained as previously described [57]. Nuclear and cytosol extracts were prepared using CelLytic NuCLEAR Extraction Kit (Merck KGaA) following manufacturer's instructions or as in Ref [58] and tested for cross‐contamination as reported [40].…”

A Beckwith–Wiedemann-Associated CDKN1C Mutation Allows the Identification of a Novel Nuclear Localization Signal in Human p57Kip2

“…Each mutagenesis product was confirmed by direct sequencing [ 38 ]. HepG2 and HEK293 cells, at 60–70% confluence, were transfected with the plasmid using Lipofectamine 3000 (Invitrogen) according to the manufacturer’s instructions [ 39 , 40 ]. Control cells were transfected with the empty vector.…”

“…Lysates obtained from the cell pellets were analyzed by Western blotting using anti-p57 and anti-actin antibodies to verify a comparable level of transfection and equal loading. Cell cycle distribution analysis was performed as previously reported in Stampone et al, 2020 [ 40 ], and the results were plotted in a histogram diagram as mean values ± standard deviation.…”