ABSTRACT
Purpose: The phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/ mTOR) pathway is a complex intracellular metabolic pathway that leads to cell growth and tumor proliferation and plays a key role in drug resistance in breast cancer. Therefore, the anti-cancer effects of oleanolic acid (OA), maslinic acid (MA), and their combination were investigated to improve the performance of the treatment strategy. Methods: We investigated the effect of OA and MA on cell viability using the WST-1 method. The synergistic effect of the combination was analyzed by isobologram analysis. In addition, the effects of the two compounds, individually and in combination, on apoptosis, autophagy, and the cell cycle were investigated in MCF7 cells. In addition, changes in the expression of PI3K/AKT/mTOR genes involved in apoptosis, cell cycle and metabolism were determined by quantitative RT-PCR. Results: MA, OA, and a combination of both caused G0/G1 arrest. Apoptosis also increased in all treated groups. The autophagosomal LC3-II formation was induced 1.74-fold in the MA-treated group and 3.25-fold in the MA-OA-treated group. The combination treatment resulted in increased expression of genes such as GSK3B, PTEN, CDKN1B and FOXO3 and decreased expression of IGF1, PRKCB and AKT3 genes. Conclusion: The results showed that the combination of these two substances showed the highest synergistic effect at the lowest dose and using MA-OA caused cancer cells to undergo apoptosis. The use of combination drugs may reduce the resistance of cancer cells to treatment.
ABSTRACT
In the current experiment, detrimental effects of high glucose condition were investigated on human neuroblastoma cells. Human neuroblastoma cell line SH-SY5Y were exposed to 5, 40, and 70 mM glucose over a period of 72 h. Survival rate and the proliferation of cells were analyzed by MTT and BrdU incorporation assays. Apoptosis was studied by the assays of flow cytometry and PCR array. In order to investigate the trans-differentiation capacity of the cell into mature neurons, we used immunofluorescence imaging to follow NeuN protein level. The transcription level of HSP70 was shown by real-time PCR analysis. MMP-2 and -9 activities were shown by gelatin Zymography. According to data from MTT and BrdU incorporation assay, 70 mM glucose reduced cell viability and proliferation rate as compared to control (5 mM glucose) and cells treated with 40 mM glucose (P < 0.05). Cell exposure to 70 mM glucose had potential to induced apoptosis after 72 h (P < 0.05). Our results also demonstrated the sensitivity of SH-SY5Y cells to detrimental effects of high glucose condition during trans-differentiation into mature neuron-like cells. Real-time PCR analysis confirmed the expression of HSP70 in cells under high content glucose levels, demonstrating the possible cell compensatory response to an insulting condition (pcontrol vs 70 mM group <0.05). Both MMP-2 and -9 activities were reduced in cells being exposed to 70 mM glucose. High glucose condition could abrogate the dynamics of neural progenitor cells. The intracellular level of HSP70 was proportional to cell damage in high glucose condition.
