Astaxanthin-loaded PLGA nanoparticles inhibit survival of MKN-45 gastric cancer cell line by modulating JAK2/STAT3/mTOR/PI3K pathway.

[BACKGROUND/AIMS] Gastric cancer (GC) is a significant global health issue with high incidence rates and poor prognoses, ranking among the top prevalent cancers worldwide. Due to undesirable side effects and drug resistance, there is a pressing need for the development of novel therapeutic strategies. Understanding the interconnectedness of the JAK2/STAT3/mTOR/PI3K pathway in tumorigenesis and the role of Astaxanthin (ASX), a red ketocarotenoid member of xanthophylls and potent antioxidant and anti-tumor activity, can be effective for cancer treatments. This study aimed to investigate the effect of ASX-loaded nanoparticles on the survival of MKN-45 GC cells and the expression of JAK2/STAT3/mTOR/PI3K, offering insights into potential targeted therapies for GC.

[METHODS] The growth status and survival rate of MKN-45 GC cell lines were determined using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide(MTT) assay, and the optimal IC50 concentration of ASX, PLGA, and ASX + PLGA was estimated. Also, the clonogenic assay was performed to determine the reproductive power and colony formation of under-treatment cells. Apoptosis and necroptosis of cells were evaluated using acridine orange (AO) staining. The western blot assessed the protein's level of expression and intensity (JAK2/STAT3/mTOR/PI3K). SPSS version 16 software was used for statistical analysis, P-value was considered lower than 0.05.

[RESULTS] Based on the results, increasing concentrations of ASX and ASX + PLGA led to a decrease in the viability of MKN-45 cells compared to the control group (P < 0.001). This value was lower for cells treated with ASX + PLGA (P = 0.003). The IC50 values for each of the studied groups (ASX, ASX + PLGA, and PLGA) were 81.45 µg/ml, 51.45 µg/ml, and 3.383 mg/ml, respectively. The levels of expression and intensity of JAK2, STAT3, and mTOR proteins in the Western blotting analysis under ASX + PLGA treatment increased compared to the control group. Conversely, the levels of expression and intensity of P-JAK2, P-STAT3, and P-mTOR proteins in the ASX + PLGA treatment group decreased by 41%, 34%, 37%, and 43%, respectively, compared to the control group. Protein expression levels and intensities of JAK2, STAT3, and mTOR significantly increased when treated with PLGA, ASX, and ASX + PLGA compared to the control group (P < 0.001).

[CONCLUSIONS] The encapsulation of ASX in PLGA nanoparticles enhances drug stability, enables targeted delivery, and allows for sustained release. This study highlights the therapeutic potential of ASX-loaded nanoparticles in targeting JAK2/STAT3/mTOR/PI3K pathways in GC treatment. Further research is needed to understand the mechanisms and clinical applications of this novel immunotherapy strategy.