β-Sitosterol targets Trx/Trx1 reductase to induce apoptosis in A549 cells via ROS mediated mitochondrial dysregulation and p53 activation

Abstract

β-Sitosterol (BS), a major bioactive constituent present in plants and vegetables has shown potent anticancer effect against many human cancer cells, but the underlying mechanism remain elusive on NSCLC cancers. We found that BS significantly inhibited the growth of A549 cells without harming normal human lung and PBMC cells. Further, BS treatment triggered apoptosis via ROS mediated mitochondrial dysregulation as evidenced by caspase-3 & 9 activation, Annexin-V/PI positive cells, PARP inactivation, loss of MMP, Bcl-2-Bax ratio alteration and cytochrome c release. Moreover, generation of ROS species and subsequent DNA stand break were found upon BS treatment which was reversed by addition of ROS scavenger (NAC). Indeed BS treatment increased p53 expression and its phosphorylation at Ser15, while silencing the p53 expression by pifithrin-α, BS induced apoptosis was reduced in A549 cells. Furthermore, BS induced apoptosis was also observed in NCI-H460 cells (p53 wild) but not in the NCI-H23 cells (p53 mutant). Down-regulation of Trx/Trx1 reductase contributed to the BS induced ROS accumulation and mitochondrial mediated apoptotic cell death in A549 and NCI-H460 cells. Taken together, our findings provide evidence for the novel anti-cancer mechanism of BS which could be developed as a promising chemotherapeutic drug against NSCLC cancers.

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“…1 HNMR and 13 CNMR in Table 1 and 12.15, 19.09, 19.57, 20.19, 19.42, 12.26, indicating six methyl groups (-CH 3 ). 13 CNMR, DEPT have resolved six methyls (-CH 3 ), 11 methylene (CH 2 ), nine methines (CH), three quaternary (C) and six glucose moiety carbon [5 methine carbon (CH) and one methylene carbon (CH 2 )] which were also confirmed by HSQC spectra. Cross-peaks in the COSY spectrum shown in Fig.…”

“…IR spectra were obtained in potassium bromide pellets on a Perkin Elmer spectrometer. 1 HNMR and 13 CNMR spectra of compound (1) were acquired on a Bruker Avance II spectrometer, operating at 400 MHz for 1 HNMR and 100 MHz for 13 CNMR in CDCl3 solvent. 1DNMR ( 1 HNMR and 13 CNMR), and 2D NMR (HSQC, COSY and HMBC) spectra of compound (2) were recorded in DMSO-d6 solvent on a Bruker Avance Neo 500 MHz NMR spectrometer, operating 500 MHz for 1 HNMR and 125 MHz for 13 CNMR with TMS as the internal standard.…”

“…CONCLUSION: 1 HNMR, 13 CNMR, DEPT-135, and 2D NMR methods were revealed that isolated compounds were taraxerol and β-sitosterol glucoside. Both show high medicinal activities.…”

“…Steroids, flavonoids, saponins, polysaccharides have been isolated from this species. Phytosterols are steroidal type saponins which have been isolated from many plants and show interesting pharmacological activities, including reducing the cholesterol level, act as a potent antitumor agent, lowering blood pressure, anti-genotoxicity, apoptosis, and anticancer nutrients 11,12,13,14 . The sterol glucoside has hydrophilic glucose moiety, which plays a vital role in prevention cholesterol entry into esterification of cholesterol 15 .…”

Potential Treatment of Breast and Lung Cancer Using Dicoma anomala, an African Medicinal Plant

“…Cancer cell lines through which β-sitosterol exerts its anticancer activities include, breast, colon, lung, gastric, and prostate cancers [ 45 ]. In A549 cells, β-sitosterol target the enzyme Trx/Trx1 reductase to induce apoptosis through ROS and p53 activation [ 46 ]. β-sitosterol anticancer activities have been explored and induce endoreduplication in HL60 and U937 cell lines via PI3K/Akt and Bcl-2 pathways.…”