Cisplatin-induced premature senescence with concomitant reduction of gap junctions in human fibroblasts

Abstract

To examine the role of gap junctions in cell senescence, the changes of gap junctions in cisplatin-induced premature senescence of primary cultured fibroblasts were studied and compared with the replicative senescent human fibroblasts. Dye transfer assay for gap junction function and immunofluorescent staining for connexin 43 protein distribution were done respectively. Furthermore, cytofluorimetry and DAPI fluorescence staining were performed for cell cycle and apoptosis analysis. p53 gene expression level was detected with indirect immunofluorescence. We found that cisplatin (10 mM) treatment could block cell growth cycle at G1 and induced premature senescence. The premature senescence changes included high frequency of apoptosis, elevation of p53 expression, loss of membranous gap junctions and reduction of dye-transfer capacity. These changes were comparable to the changes of replicative senescence of human fibroblasts. It was also concluded that cisplatin could induce premature senescence concomitant with inhibition of gap junctions in the fibroblasts. Loss of functional gap junctions from the cell membrane may account for the reduced intercellular communication in the premature senescent fibroblasts. The cell system we used may provide a model useful for the study of the gap junction thus promoting agents against premature senescence.

Cisplatin and Oxaliplatin Inhibit Gap Junctional Communication by Direct Action and by Reduction of Connexin Expression, Thereby Counteracting Cytotoxic Efficacy

“…It was reported that platinum-based reagents, including cisplatin, affected GJIC by reducing the amount or inducing aberrant intracellular localization of connexin proteins, or by regulating the mitogen-activated protein kinase-dependent phosphorylation of specific sites on connexins (Fiorini et al, 2004;Zhao et al, 2004;Prochá zka et al, 2007). However, the effects reported here on purified, reconstituted connexin channels establish that inhibition can occur by direct interaction of cisplatin/oxaliplatin with connexin protein and that this has a detrimental effect on toxic efficacy.…”

Gap Junctions and Cochlear Homeostasis

“…In isolated Hensen cells, it was shown that the ototoxic antibiotic gentamicin reduced the conductance of the gap junctions (Todt et al, 1999). In line with this observation another ototoxic drug, cisplatin, was able to uncouple the gap junctions of fibroblasts (Zhao et al, 2004). Since the effects of gentamicin on gap junction coupling of Hensen cells could be counterbalanced by application of catalase, it was concluded that gentamicin first stimulates the production of H 2 O 2 , which!…”

Long-Term Cultured Human Term Placenta-Derived Mesenchymal Stem Cells of Maternal Origin Displays Plasticity

“…Population doubling time indicates the growth rate of the placental MSCs [22], population doubling (PD) $\text{PD}=\frac{\ln \left(\text{Nf}/\text{Ni}\right)}{\ln 2},\mathrm{\hspace{0.17em}\hspace{0.17em}}$ where ln equals natural logarithm, Nf equals final cell count, Ni equals initial cell count $\text{Gt}\mathrm{\hspace{0.17em}\hspace{0.17em}}=\frac{t}{\text{PD}},$ t = Time in hours after cell seeding.…”