Y2O3NPs induce selective cytotoxicity, genomic instability, oxidative stress and ROS mediated mitochondrial apoptosis in human epidermoid skin A-431 Cancer cells

Abstract

Yttrium oxide nanoparticles (Y₂O₃NPs) have emerged as a promising avenue for cancer therapy, primarily due to their distinctive properties that facilitate selective targeting of cancer cells. Despite their potential, the therapeutic effects of Y₂O₃NPs on human epidermoid skin cancer remain largely unexplored. This study was thus conducted to investigate the impact of Y₂O₃NPs on both human skin normal and cancer cells, with an emphasis on assessing their cytotoxicity, genotoxicity, and the mechanisms underlying these effects. Cell viability and apoptosis induction were assessed using the Sulforhodamine B and chromatin diffusion assay, respectively. Reactive oxygen species (ROS) level, mitochondrial membrane potential integrity, oxidative stress markers and expression level of apoptotic and mitochondrial genes were also estimated. Our findings highlight the selective and significant cytotoxicity of Y₂O₃NPs against human epidermoid A-431 cancer cells. Notably, exposure to five Y₂O₃NPs concentrations (0.1, 1, 10, 100 and 1000 µg/ml) resulted in a high concentration-dependent reduction in cell viability and a corresponding increase in cell death observed 72 h post-treatment specifically in A-431 cancer cells, while normal skin fibroblast (HSF) cells exhibited minimal toxicity. When A-431 cancer cells were treated with the half-maximal inhibitory concentration (IC50) of Y₂O₃NPs for 72 h, a significant increase in ROS generation was noted. This led to oxidative stress, along with severe damage to genomic DNA and mitochondrial membrane potential, triggering substantial apoptosis. Furthermore, a concurrent significant upregulation of apoptotic p53 and mitochondrial ND3 genes was observed, coupled with a notable decrease in the anti-apoptotic Bcl2 gene expression.Overall, Y₂O₃NPs demonstrate considerable promise as a therapeutic agent for skin epidermoid cancer due to their ability to selectively target and induce cytotoxic effects in A-431 cancer cells, all while causing minimal harm to normal HSF cells. This selective cytotoxicity appears to be associated with Y₂O₃NPs' ability to induce excessive ROS production and subsequent oxidative stress, leading to significant genomic DNA fragmentation, loss of mitochondrial permeability, and alterations in apoptotic and mitochondrial genes' expression, ultimately promoting apoptosis in A-431 cancer cells. These findings establish a foundation for further research into the utilization of Y₂O₃NPs in targeted cancer therapies and underscore the necessity for ongoing investigation into their safety and efficacy in clinical applications.

Keywords: Cytotoxicity, genotoxicity, apoptosis; Oxidative stress and mitochondria; Yttrium oxide nanoparticles.

Fig. a

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Fig. 1

X-ray diffraction (XRD) pattern detected using X-Ray Diffractometers confirmed the purity and crystalline structure of purchased Y 2 O 3 NPs

Fig. 2

Particles’ Size Distribution and Zeta Potential Distribution of Y 2 O 3 NPs measured using Zetasizer revealed well dispersion and stability of suspended Y 2 O 3 NPs.

Fig. 3

Photomicrograph of TEM imaging showed the well distribution and cubic shape of Y 2 O 3 NPs with an average particle size of 14.15 nm.

Fig. 4

Viability of normal HSF and cancerous A-431 cells detected using SRB assay after exposure to five different concentrations of Y 2 O 3 NPs (0.1, 1, 10, 100 and 1000 µg/ml) for 72 h.

Fig. 5

Regression line and correlation coefficient between Y 2 O 3 NPs different concentrations (7.47. 14.94 and 28.89 µg/ml) and the assessed %A-431 cells with diffused damaged DNA using Chromatin Diffusion assay.

Fig. 6

Examples for the scored A-431 cells with (a) intact DNA and (b) diffused DNA regardless treatment using Chromatin Diffusion assay.

Fig. 7

Level of ROS generation analyzed using 2 , 7 DCFH-DA dye within control untreated A-431 cells and A-431 cells treated with doxorubicin- or Y 2 O 3 NPs (7.47. 14.94 and 28.89 µg/ml) for 72 h .

Fig. 8

Regression lines and correlation coefficient between Y 2 O 3 NPs concentrations (7.47. 14.94 and 28.89 µg/ml) and the measured MDA level, CAT activity and SOD activity using suitable biochemical kits.

Fig. 9

Integrity of mitochondrial membrane potential studied using Rhodamine-123 dye in the control untreated A-431 cells and A-431 cells treated with doxorubicin- or Y 2 O 3 NPs (7.47. 14.94 and 28.89 µg/ml) for 72 h.

Fig. 10

Regression lines and correlation coefficient between Y2O3NPs concentrations (7.47. 14.94 and 28.89 µg/ml) and the expression level of p53, Bcl2 and ND3 genes measured using qRT-PCR.