Enhanced anticancer efficacy of docetaxel through galbanic acid encapsulated into PLA-PEG nanoparticles in treatment of colon cancer, in vitro and in vivo study

Cancer is one of the most leading causes of human mortality and despite outstanding breakthrough in introducing new therapeutic approaches, the clinical outcomes are disappointing. Therefore, extensive research in design and preparation of more efficient drug delivery systems can open a window to shine light into the therapeutic modality. In this study, we evaluated the effect of galbanic acid (GBA) encapsulated into PLA-PEG nanoparticles (NPs) to enhanced anticancer efficacy of docetaxel (DOC) for the treatment of colon cancer. Prepared NPs were characterized by different methods in terms of size, zeta potential, and drug loading capacity. MTT assay was used to investigate the anti-proliferation of GBA-loaded PEG-PLA NPs along with DOC. The therapeutic efficacy of PEG-PLA@GBA NPs & DOC was further investigated in C26 tumor-bearing BALB/c mice model. The resulting NPs were narrowly distributed (PDI = 0.06) with the mean diameter of 148 ± 9 nm with somewhat negative charge. GBA were efficiently loaded into mPEG-PLA NPs with encapsulation efficiency of about 40% ± 3. Cytotoxicity studies showed that NPs loaded with GBA and fixed concentration of docetaxel (20 nM) have higher toxicity (IC50 = 6 ± 1.8 µM) than either PEG-PLA@GBA (IC50 = 8 ± 1.2 µM) or free GBA (IC50 = 15 ± 3.5 µM) in C26 cells. In vivo studies revealed a synergistic effect of PEG-PLA@GBA NPs and DOC on tumor growth inhibition and survival rate in comparison with monotherapy approach.

In vitro Study of Radiosensitivity Effects of Galbanic Acid on Ovarian Tumor Cells (OVCAR-3 Cell Line)

Background and aims: Radiotherapy ranks among the most important procedures in ovarian cancer therapy. However, radioresistance is becoming more prevalent and is one of the main causes of poor clinical outcomes. To overcome this problem, radiosensitizers may be used. The present study aimed to evaluate the radiosensitizing properties of galbanic acid (GBA) on ovarian cancer cells in vitro. Materials and methods: OVCAR-3 cells, an ovarian cancer cell line, were treated with increasing concentrations of GBA (5, 10, 20, and 40 μg/mL) for 24, 48, and 72 h to determine its half-maximal inhibitory concentration (IC50). Cell viability was assessed by alamar Blue assay. The cells treated with 10 μg/mL GBA for 24 h were exposed to increasing doses of radiation (1, 2, and 4 Gy) and the survival fraction was investigated by clonogenic assay. Results: Assessment of cell viability indicated that GBA caused toxicity in a dose-dependent manner. Additionally, GBA pretreatment significantly improved the radiosensitivity of the cells, and survival fraction data indicated synergy between GBA and radiation. Conclusion: Taken together, the current findings highlight GBA as a potent radiosensitizing agent; however, further research is required to determine the molecular mechanisms of the observed effect both in vitro and in vivo. It is also suggested that the radiosensitization effect of GBA on other cell types should be studied in the future.

Effects of Galbanic Acid on Proliferation, Migration, and Apoptosis of Glioblastoma Cells Through the PI3K/Akt/MTOR Signaling Pathway

Background: Glioblastoma is one of the most aggressive tumors of central nervous system. Galbanic acid, a natural sesquiterpene coumarin, has shown favorable effects on cancerous cells in previous studies. Objective: The aim of the present work was to evaluate the effects of galbanic acid on proliferation, migration, and apoptosis of the human malignant glioblastoma (U87) cells. Methods: Anti-proliferative activity of the compound was determined by MTT assay. Cell cycle alterations and apoptosis were analyzed via flow cytometry. Action on cell migration was evaluated by scratch assay and gelatin zymography. Quantitative Real-Time PCR was used to determine the expression of genes involved in cell migration (matrix metalloproteinases, MMPs) and survival (the pathways of PI3K/Akt/mTOR and WNT/β-catenin). Alteration in the level of protein Akt was determined by Western blotting. Results: Galbanic acid significantly decreased cell proliferation, inhibited cell cycle, and stimulated apoptosis of the glioblastoma cells. Also, it could decrease migration capability of glioblastoma cells, which was accompanied by an inhibition in the activity and expression of MMP2 and MMP9. While galbanic acid reduced the gene expression of Akt, mTOR, and PI3K and increased the PTEN expression, it had no significant effect on WNT, β-catenin, and APC genes. Also, the protein level of p-Akt decreased after treatment with galbanic acid. The effects of galbanic acid were observed at concentrations lower than those of temozolomide. Conclusion: Galbanic acid decreased proliferation, cell cycle progression, and survival of glioblastoma cells through inhibiting PI3K/Akt/mTOR pathway. This compound also reduced migration capability of the cells by suppressing the activity and expression of MMPs.