CTPS cytoophidia formation affects cell cycle progression and promotes TSN‑induced apoptosis of MKN45 cells

Abstract

Cytidine triphosphate synthase (CTPS) forms filamentous structures termed cytoophidia in numerous types of cell. Toosendanin (TSN) is a tetracyclic triterpenoid and induces CTPS to form cytoophidia in MKN45 cells. However, the effects of CTPS cytoophidia on the proliferation and apoptosis of human gastric cancer cells remain poorly understood. In the present study, CTPS-overexpression and R294D-CTPS mutant vectors were generated to assess the effect of CTPS cytoophidia on the proliferation and apoptosis of gastric cancer MKN45 cells. Formation of CTPS cytoophidia significantly inhibited MKN45 cell proliferation (evaluated using EdU incorporation assay), significantly blocked the cell cycle in G 1 phase (assessed using flow cytometry) and significantly decreased mRNA and protein expression levels of cyclin D1 (assessed by reverse transcription-quantitative PCR and western blotting, respectively). Furthermore, the number of apoptotic bodies and apoptosis rate were markedly elevated and mitochondrial membrane potential was markedly decreased. Moreover, mRNA and protein expression levels of Bax increased and Bcl-2 decreased markedly in MKN45 cells following transfection with the CTPS-overexpression vector. The proliferation rate increased, percentage of G 1 /G 0 -phase cells decreased and apoptosis was attenuated in cells transfected with the R294D-CTPS mutant vector and this mutation did not lead to formation of cytoophidia. The results of the present study suggested that formation of CTPS cytoophidia inhibited proliferation and promoted apoptosis in MKN45 cells. These results may provide insights into the role of CTPS cytoophidia in cancer cell proliferation and apoptosis.

Probenecid ameliorates testosterone‐induced benign prostatic hyperplasia: Implications of PGE‐2 on ADAM‐17/EGFR/ERK1/2 signaling cascade

“…[ 83 ] The transcription of cell proliferative genes begins with the nuclear translocation of p‐ERK. [ 84,85 ] In agreement with the current results, Said et al, [ 43 ] found a high proliferation rate of prostate in TST‐induced BPH, that was weakened by the inhibition of the ERK1/2 signaling pathway. [ 83 ] On the other hand, ERK1/2 activation inhibited apoptotic signaling by Fas and TRAIL receptors, which can explain the low expression of proapoptotic Bax.…”

“…[ 83 ] On the other hand, ERK1/2 activation inhibited apoptotic signaling by Fas and TRAIL receptors, which can explain the low expression of proapoptotic Bax. [ 26,84,86 ] In parallel with these results, low apoptotic bodies were well detected in TST‐induced BPH experimental models. [ 60,66 ]…”