The anticancer effects of 7-Methoxyheptaphylline against the human retinoblastoma cells are facilitated via S-phase cell cycle arrest, mitochondrial apoptosis and inhibition of Wnt/β-catenin signalling pathway.

The main purpose of the current study was to evaluate the anticancer action of 7-Methoxyheptaphylline in Y-79 human retinoblastoma cells along with evaluating its effects on cellular apoptosis, cell cycle phase distribution and Wnt/β-catenin signalling pathway. The retinoblastoma cell line RbY-79 was used in this study. Cell viability was assessed by WTS-1 assay while apoptotic studies were carried out by DAPI, acridine orange (AO)/ethidium bromide (EB), annexin V + propidium iodide (PI) staining using fluorescence microscopy and flow cytometry. Effects on cell cycle progression were studied using Annexin V/PI staining in combination with flow cytometry. Western blot assay was used to examine the effects on Bax, Bcl-2 and proteins associated with Wnt/β-catenin signalling pathway. The results indicated that 7-Methoxyheptaphylline suppressed the viability of the Y-79 cells concentration-dependently with IC50 value of 15.5 μM. The percentage of the DAPI-positive cells showed a significant upsurge reminiscent of the apoptosis in the Y-79 retinoblastoma cells. 7-Methoxyheptaphylline also caused considerable nuclear fragmentation of the Y-79 retinoblastoma cells, representative of apoptosis. The apoptosis percentage increased significantly as the dose of the 7-Methoxyheptaphylline increased from 0 to 12, 24 and 48 µM. The molecule caused upregulation of Bax and downregulation of Bcl-2 in Y-79 retinoblastoma cells. 7-Methoxyheptaphylline also caused S-phase cell cycle arrest with concomitant concentration-dependent decline in the expression levels of cyclin A, E and D1. It was also seen that increasing doses of 7-Methoxyheptaphylline led to a dose-dependent decline in the expression levels of wnt-13a and β-catenin. In conclusion, it is believed that the molecule may prove to be a promising anticancer agent for the treatment of retinoblastoma.