Ceramide induces the apoptosis of non‑small cell lung cancer cells through the Txnip/Trx1 complex

Abstract

ceramide is a biologically active sphingomyelin that inhibits cell growth and proliferation. In previous studies, it was demonstrated that the use of lipopolysaccharides induces acid sphingomyelinases to produce ceramide, promoting lung cancer cell apoptosis; however, the specific mechanisms of this action remain unclear. Thioredoxin-interacting protein (Txnip) plays an important role in the signal transmission of redox reactions inside and outside the cell. Thus, it was hypothesized that ceramide induces apoptosis in lung adenocarcinoma cells (A549 and Pc9) by modulating the Txnip/Trx1 complex. In the present study, the cell counting kit-8 method was used to detect cell activity and the drug concentration. Hoechst 33258 staining and flow cytometry were used to detect cell apoptosis, and the positional association between Txnip and Trx1 upregulated by ceramide was observed by immunofluorescence confocal microscopy. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were used to detect the changes in related gene, mRNA and protein expression levels. The results revealed that ceramide treatment resulted in the upregulation of Txnip and in the reduction of Trx1 activities. However, the Txnip inhibitor, verapamil, reversed these changes. The analysis of mRNA expression further verified the changes observed in the protein expression of Txnip, Trx1 and apoptosis-related proteins. On the whole, the present study demonstrates that ceramide induces the apoptosis of lung cancer cells by regulating the Txnip/Trx1 complex.

Developing new ceramide analogs against non-small cell lung cancer (NSCLC)

“…A recent study has reported a novel and small molecule SphK1/2 dual inhibitor, SKI-349, with IC 50 s on primary NSCLC cells and immortalized celllines of ~5-10 μM [21]. In contrast, another recent study has reported the IC 50 of exogenous C2-Cer on NSCLC cell-lines to be ~100 μM [22]. These data together highlight the potential of our ceramide analogs as promising candidates for sphingolipid-based NSCLC therapies.…”

“…Our previous microarray analysis identified specific cellular genes affected by ceramide analogs, such as AURKA (Aurora A kinase) and CDCA3 (cell division cycle-associated 3), which play crucial roles in the survival of virus-associated lymphoma cells [23]. Additionally, exogenous ceramideinduced apoptosis in NSCLC cells has been linked to the Txnip/Trx1 complex [22]. The thioredoxin-interacting protein (Txnip) regulates a variety of oxidative stresses together with glutathione; it can also inhibit the exchange between the disulfide bonds of thioredoxin (Trx)1 to inhibit the reducing activity of Trx [24][25][26][27].…”

Ceramides and Ceramide Synthases in Cancer: Focus on Apoptosis and Autophagy

“…VDAC channels are a platform for the recruitment of pro-apoptotic Bak and Bax into mitochondria, leading to cytochrome c release and permeabilization of the OMM (116). Moreover, C2cermide has been found to induce apoptosis in lung adenocarcinoma cells (A549 and PC9) via regulation of the thioredoxin-interacting protein (Txnip) (117). Treatment of these cells with C2-ceramide caused an increase in the activity of caspase-3.…”

Sphingolipid Metabolism and Signaling in Lung Cancer: A Potential Therapeutic Target

“…Unlike S1P, ceramide is thought to be an important secondary messenger involved in apoptosis and necrosis pathways in both normal and cancer cells [ 16 , 17 ]. In vitro studies revealed that C2 ceramide can induce apoptosis in lung cancer cells by modulating the TXNIP/Trx1 complex, inhibiting AKT and NF- κ B activity, and downregulating survivin and cyclin A2 [ 18 , 19 ]. In addition, C2 ceramide was shown to significantly affect autophagy-related factors, including SIRT1, LAMP2, and LC3, induce sustained autophagy, and increase apoptosis in non-small cell lung cancer [ 20 ].…”