Harmine induces cell cycle arrest and mitochondrial pathway-mediated cellular apoptosis in SW620 cells via inhibition of the Akt and ERK signaling pathways

Abstract

Harmine, a β-carboline alkaloid isolated from the seeds of Peganum harmala, possesses both antitumor and anti‑nociceptive effects and inhibits human DNA topoisomerase. However, no detailed data are available concerning the mechanisms of harmine in human colorectal carcinoma SW620 cells. In the present study, we demonstrated that harmine inhibited the proliferation of SW620 cells in a dose-dependent manner using MTT and clone formation assays, and the IC50 value of harmine on the growth inhibition of SW620 cells for 48 h was 5.13 µg/ml. PI staining showed that harmine altered the cell cycle distribution by decreasing the proportion of cells in the G0-G1 phase and increasing the proportion in the S and G2-M phase. The expression level of cyclin D1 was decreased, while the expression of cyclin A, E2 and B1, CDK1/cdc2, Myt-1 and p-cdc2 (Tyr15) were increased, which was in accordance with the S and G2/M phase arrest. Hoechst 33258 staining revealed nuclear fragmentation, chromosomal condensation and cell shrinkage in the SW620 cells treated with harmine. Flow cytometry revealed that the percentage of apoptotic sub-G1 cells increased from 7.19 to 26.58%, while in the control group, sub-G1 cells only increased from 1.53 to 1.60%. Furthermore, early and late apoptotic cells were increased from 11.96 to 26.38% when incubated with the indicated concentration of harmine for 48 h, while in the control group, <8% of cells underwent apoptosis. JC-1 staining revealed that harmine decreased mitochondrial transmembrane potential (ΔΨm). The apoptosis of SW620 cells was also detected by western blot analysis, showing caspase-3 and -9, and PARP activation; the downregulation of Bcl-2, Mcl-1, Bcl-xL; and the upregulation of Bax. The expression of p-ERK, p-Akt (Ser473) and p-Akt (Thr308) was inhibited, and phosphorylation of downstream targets of Akt, such as p-FoxO3a and p-GSK‑3β were also attenuated. In conclusion, harmine induces cell cycle arrest and mitochondrial pathway-mediated cellular apoptosis in SW620 cells via inhibition of the Akt and ERK signaling pathways.

Knockdown of BCL6 Inhibited Malignant Phenotype and Enhanced Sensitivity of Glioblastoma Cells to TMZ through AKT Pathway

“…But in U251 cells (one of the p53-mutant cell lines), p53 expression had no significant changes. Besides, some research also showed that several molecules could upregulate BCL2 to inhibit cell apoptosis by AKT and ERK signaling pathways [ 26 , 27 ] which was consistent with our result that knockdown of BCL6 inhibited the AKT and ERK pathways. In addition, BCL2 and Bax are key upstream regulatory factors of caspase cascade which involved in apoptosis [ 28 ], and regulation of BCL2/Bax expression alters proliferation and apoptosis in glioblastoma [ 29 ].…”

Harmine and its derivatives: Biological activities and therapeutic potential in human diseases

“…Apoptotic cellular death is accompanied by activation of Bax, PARP, and caspase-3/-9 along with down-regulation of Bcl-2 and Mcl-1 levels. Harmine also inhibited ERK, and Akt pathways in SW620 cells (Liu et al, 2016).…”

Cytotoxic and Apoptotic Activity of the Novel Harmine Derivative ZC-14 in Sf9 Cells

“…However, whether harmine was responsible for the effects remains unclear [ 32 ]. Previous research showed that dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) was one of targets of harmine and the anticancer and antiviral effects were via inhibiting the phosphorylation of DYRK1A substrates [ 22 ]. Simultaneously, the adverse effects including deleterious cardiovascular effects and nigrostriatal neurotoxicity, were caused by chronic use of harmine in users and rat.…”

“…Anti-proliferation and apoptosis induction were demonstrated as the main cytotoxic effects. For example, harmine and its analogues have the function of anti-proliferation and apoptosis induction in many cancer cell lines, such as human thyroid cancer TPC1 cells, human colorectal carcinoma SW620 cells and human prostate cancer C4-2 cells [ 21 , 22 , 23 ]. Our previous research found that harmine could induce G2/M cell cycle arrest and apoptosis in the Spodoptera litura SL-1 cell line [ 24 ].…”