Crosstalk between ER-stress and apoptosis in irradiated HepG2 cells with gemcitabine: implication of PI3K/AKT and IκB/NF-κB signaling pathways

Proton irradiation induced reactive oxygen species promote morphological and functional changes in HepG2 cells

The increased use of proton therapy has led to the need of better understanding the cellular mechanisms involved. The aim of this study was to investigate the effects induced by the accelerated proton beam in hepatocarcinoma cells. An existing facility in IFIN-HH, a 3 MV Tandetron™ accelerator, was used to irradiate HepG2 human hepatocarcinoma cells with doses between 0 and 3 Gy. Colony formation was used to assess the influence of radiation on cell long-term replication. Also, the changes induced at the mitochondrial level were shown by increased ROS and ATP levels as well as a decrease in the mitochondrial membrane potential. An increased dose has induced DNA damages and G₂/M cell cycle arrest which leads to caspase 3/7 mediated apoptosis and senescence induction. Finally, the morphological and ultrastructural changes were observed at the membrane level and the nucleus of the irradiated cells. Thus, proton irradiation induces both morphological and functional changes in HepG2 cells.

Withania somnifera Modulates Radiation-Induced Generation of Lung Cancer Stem Cells via Restraining the Hedgehog Signaling Factors

Cancer stem cells (CSCs) are implicated in the genesis, development, and recurrence of lung cancer (LC) with great resistance to radiation and chemotherapy. The aim of this study is to assess the inhibitory potential of ethanol extract of Withania somnifera (WS); 500 mg/kg body-weight/day and 8 Gy of ionizing radiation (IR) could inhibit the stemness gene and confer the radiosensitizing effect of W. somnifera extract in the female rat LC model. Compared to IR or WS, the in vitro assay showed that WS + IR potentiates proliferation-inhibition and cell death of the A-549 cell line and suppresses sphere formation. The Hedgehog (Hh) signaling associated with the expression levels of lung CSC markers, octamer-binding transcription factor-4 (OCT4), SRY-box 2 (SOX2), CD133, ATP Binding Cassette Subfamily G Member 2 (ABCG2), and NANOG was upregulated with stimulated epithelial-to-mesenchymal transition (EMT) indicators α-smooth muscle actin (α-SMA), Drosophila embryonic protein (SNAIL-1), Vimentin, and E-cadherin in the LC rat model. The W. somnifera extract plus IR inhibits Hh activation factors, which has resulted in the suppression of CSC gene markers and EMT factors. W. somnifera extract may be a significant adjuvant in the course of radiotherapy, contributing to the termination of tumor progression, and thus providing cure insights into the molecular mechanisms of lung CSCs intervention.

Mangosteen Hinders Gamma Radiation-Mediated Oxidative Stress and Liver Injury by Down-Regulating TNF-α/NF-κB and Pro-Fibrotic Factor TGF-β1 Inducing Inflammatory Signaling

Background:

Liver injury due to ionizing radiation exposure either accidental or after radiotherapy treatment, may lead to many alterations in proteins expression related to inflammation or apoptosis. Our study investigated the curative effect of Mangosteen (MGS) extract (fruit rind) against ionizing radiation (IR) induced liver damage.

Methods:

Hepatotoxicity was induced in Wister rats by exposure to an acute single dose (6 Gy) of IR while MGS was given orally to rats (500 mg/kg bwt) and administered daily for 30 days after irradiation.

Results:

MGS treatment has significantly attenuated redox imbalance state and toxicity induced by protracted exposure to gamma-rays in liver tissues, which was substantiated by the significant amelioration of liver function tests, MDA contents, antioxidant enzymes (SOD and CAT) activities and NO level. MGS inhibited also the inflammatory markers (TNF-alpha, IL-6 and CRP) and downregulated transcriptional factor NF-Kappa-B/TGF-β1. These alterations were concomitant with an improvement of the Proliferating cell nuclear antigen (PCNA) which is a protein expressed in the nuclei of cells during cell cycle and is important for both DNA synthesis and DNA repair. These results were confirmed by amelioration in histological and ultrastructural examinations.

Conclusion:

We concluded that MGS could ameliorate via minimizing significantly the amount of oxidative damage, inflammations disturbances and pro-apoptotic alternations induced by IR. MGS may be a promising supplement with protective effects from irradiation-induced injury such as TNF-α/NF-κB/TGF-β1 management.