Oxidative stress: A critical hint in ionizing radiation induced pyroptosis

NORAD-Regulated Signaling Pathways in Breast Cancer Progression

Long non-coding RNA activated by DNA damage (NORAD) has recently been associated with pathologic mechanisms underlying cancer progression. Due to NORAD's extended range of interacting partners, there has been contradictory data on its oncogenic or tumor suppressor roles in BC. This review will summarize the function of NORAD in different BC subtypes and how NORAD impacts crucial signaling pathways in this pathology. Through the preferential binding to pumilio (PUM) proteins PUM1 and PUM2, NORAD has been shown to be involved in the control of cell cycle, angiogenesis, mitosis, DNA replication and transcription and protein translation. More recently, NORAD has been associated with PUM-independent roles, accomplished by interacting with other ncRNAs, mRNAs and proteins. The intricate network of NORAD-mediated signaling pathways may provide insights into the potential design of novel unexplored strategies to overcome chemotherapy resistance in BC treatment.

Enhancement of Radiation Sensitivity by Cathepsin L Suppression in Colon Carcinoma Cells

Cancer is one of the main causes of death globally. Radiotherapy/Radiation therapy (RT) is one of the most common and effective cancer treatments. RT utilizes high-energy radiation to damage the DNA of cancer cells, leading to their death or impairing their proliferation. However, radiation resistance remains a significant challenge in cancer treatment, limiting its efficacy. Emerging evidence suggests that cathepsin L (cath L) contributes to radiation resistance through multiple mechanisms. In this study, we investigated the role of cath L, a member of the cysteine cathepsins (caths) in radiation sensitivity, and the potential reduction in radiation resistance by using the specific cath L inhibitor (Z-FY(tBu)DMK) or by knocking out cath L with CRISPR/Cas9 in colon carcinoma cells (caco-2). Cells were treated with different doses of radiation (2, 4, 6, 8, and 10), dose rate 3 Gy/min. In addition, the study conducted protein expression analysis by western blot and immunofluorescence assay, cytotoxicity MTT, and apoptosis assays. The results demonstrated that cath L was upregulated in response to radiation treatment, compared to non-irradiated cells. In addition, inhibiting or knocking out cath L led to increased radiosensitivity in contrast to the negative control group. This may indicate a reduced ability of cancer cells to recover from radiation-induced DNA damage, resulting in enhanced cell death. These findings highlight the possibility of targeting cath L as a therapeutic strategy to enhance the effectiveness of RT. Further studies are needed to elucidate the underlying molecular mechanisms and to assess the translational implications of cath L knockout in clinical settings. Ultimately, these findings may contribute to the development of novel treatment approaches for improving outcomes of RT in cancer patients.

Orange peels and Chlorella vulgaris supplementation ameliorate gamma radiation-induced oxidative stress by regulating TGF-β and NOX2/NOX4 signaling pathways

Numerous studies revealed that Chlorella vulgaris and orange peels are potential sources for many valuable compounds such as flavonoids, which are natural polyphenols with antioxidant capacities that lessen oxidative stress via suppressing ROS levels. Thus, this study was designed to investigate their radioprotective efficiency either alone or in combination as natural food supplements. Sixty-four male Albino rats were divided into eight groups (n = 8) as follows: control, orange peel (10% in diet), C. vulgaris (1% in diet), orange peel + C. vulgaris, gamma irradiated (2Gy twice per week up to 8Gy), orange peel + gamma irradiation, C. vulgaris + gamma irradiation, and orange peel + C. vulgaris + gamma irradiation. After the experiment, blood serums were collected for biochemical analysis, whole bloods were collected for blood picture, bone marrows were collected for GSH, MDA, TGF-β, NOX2 and NOX4, and liver tissues were collected for histopathological evaluation. Current study revealed that exposure to gamma irradiation induced a significant disturbance in liver function markers (ALT and AST), kidney function markers (urea and creatinine), cholesterol and triglycerides levels in serum. In addition, a significant decrease in WBCs, RBCs, PLT, and Hb in blood of irradiated rats. Moreover, a significant elevation in TGF-β, NOX2, NOX4 activities, and MDA level, while showed a marked decrease in GSH concentration. Furthermore, hepatic inflammation appeared in the histopathological examination. Orange peels or C. vulgaris treatments showed acceptable amelioration in all measured parameters, combination between orange peels and C. vulgaris showed statistically significant additive amelioration in radiation induced disturbance.

Treating atopic-dermatitis-like skin lesions in mice with gelatin-alginate films containing 1,4-anhydro-4-seleno-d-talitol (SeTal)

New compounds and pharmacological strategies offer alternatives for treating chronic skin diseases, such as atopic dermatitis (AD). Here, we investigated the incorporation of 1,4-anhydro-4-seleno-d-talitol (SeTal), a bioactive seleno-organic compound, in gelatin and alginate (Gel-Alg) polymeric films as a strategy for improving the treatment and attenuation of AD-like symptoms in a mice model. Hydrocortisone (HC) or vitamin C (VitC) were incorporated with SeTal in the Gel-Alg films, and their synergy was investigated. All the prepared film samples were able to retain and release SeTal in a controlled manner. In addition, appreciable film handling facilitates SeTal administration. A series of in-vivo/ex-vivo experiments were performed using mice sensitized with dinitrochlorobenzene (DNCB), which induces AD-like symptoms. Long-term topical application of the loaded Gel-Alg films attenuated disease symptoms and pruritus, with suppression of the levels of inflammatory markers, oxidative damage, and the skin lesions associated with AD. Moreover, the loaded films showed superior efficiency in attenuating the analyzed symptoms when compared to hydrocortisone (HC) cream, a traditional AD-treatment, and decreased the inherent drawbacks of this compound. In short, incorporating SeTal (by itself or with HC or VitC) in biopolymeric films provides a promising alternative for the long-term treatment of AD-type skin diseases.

Modification of protein secondary structure as an indicator of radiation-induced abscopal effect: A spectroscopic investigation

In this study, we investigate the abscopal effect induced in the brain, lung and kidney as a result of partial irradiation of experimental animals with 2 Gy γ-rays. Modifications in the protein secondary structure were used as indicator for the abscopal effect. FTIR spectroscopy and analysis of the amide I and amide II absorption bands suggested possible modifications in the protein secondary structure in the brain and kidney following irradiation. Significant shift in the amide I band was recorded only in the brain. However, the amide I/amide II band area ratio for the three organs examined varied differentially in the irradiated groups as compared with the sham-irradiated group. Employing the lorentzian model to analyze the amide I band of the FTIR spectra, we dissected the amide I band into its components, each component represents one form of the protein secondary structure. Calculation of the weight percentage contribution of each of the protein secondary structure revealed decrease in the α-helix contribution associated with equivalent increase in β-sheets and turns/random coils contributions in the brain and kidney, however the response was more evident in the brain. No change in the α-helix or β-sheets contributions was reported in the lung following irradiation. The data suggest the induction of abscopal effect in the brain and kidney rather than the lung in the form of protein conformation modification. The data also indicate that the abscopal effect is comparable to the effect of direct irradiation in both of the brain and kidney.

The Detection of DNA Damage Response in MCF7 and MDA-MB-231 Breast Cancer Cell Lines after X-ray Exposure

Radiotherapy is one of the main options to cure and control breast cancer. The aim of this study was to investigate the sensitivity of two human breast cancer cell lines, MCF7 and MDA-MD-231, to radiation exposure at timepoints 4 h and 24 h after radiation. MCF7 and MDA-MD-231 were irradiated with different radiation doses using a Gilardoni CHF 320 G X-ray generator (Mandello del Lario, Italy) at 250 kVp, 15 mA [with half-value layer (HVL) = 1.6 mm copper]. The ApoTox-Glo triplex assay combines three assays used to assess viability, cytotoxicity, and apoptosis. The expression of γH2AX and BAX was analyzed by Western blotting. Viability and cytotoxicity did not change 4 h and 24 h after irradiation in either cell line, but we found a significant increase in the expression of cleaved caspase-3/7 at 24 h after irradiation with 8.5 Gy in MDA-MB231. The expression of γH2AX and BAX was low in MCF7, whereas the expression of γH2AX and BAX increased with radiation dose in a dose-dependent manner in MDA-MB231. The results show that the MCF7 cell line is more radioresistant than the MDA-MB 231 cell line at 4 h and 24 h after X-ray irradiation. In contrast, MDA-MB-231 cells were radiosensitive at a high radiation dose of 8.5 Gy at 24 h after irradiation. γH2AX and BAX indicated the radiosensitivity in both cell lines. These results open the possibility of using these cancer cell lines as models for testing new therapeutic strategies to improve radiation therapy.

Combining Nanocarrier-Assisted Delivery of Molecules and Radiotherapy

Cancer is responsible for a significant proportion of death all over the world. Therefore, strategies to improve its treatment are highly desired. The use of nanocarriers to deliver anticancer treatments has been extensively investigated and improved since the approval of the first liposomal formulation for cancer treatment in 1995. Radiotherapy (RT) is present in the disease management strategy of around 50% of cancer patients. In the present review, we bring the state-of-the-art information on the combination of nanocarrier-assisted delivery of molecules and RT. We start with formulations designed to encapsulate single or multiple molecules that, once delivered to the tumor site, act directly on the cells to improve the effects of RT. Then, we describe formulations designed to modulate the tumor microenvironment by delivering oxygen or to boost the abscopal effect. Finally, we present how RT can be employed to trigger molecule delivery from nanocarriers or to modulate the EPR effect.

H2A.X Phosphorylation in Oxidative Stress and Risk Assessment in Plasma Medicine

At serine₁₃₉-phosphorylated gamma histone H2A.X (γH2A.X) has been established over the decades as sensitive evidence of radiation-induced DNA damage, especially DNA double-strand breaks (DSBs) in radiation biology. Therefore, γH2A.X has been considered a suitable marker for biomedical applications and a general indicator of direct DNA damage with other therapeutic agents, such as cold physical plasma. Medical plasma technology generates a partially ionized gas releasing a plethora of reactive oxygen and nitrogen species (ROS) simultaneously that have been used for therapeutic purposes such as wound healing and cancer treatment. The quantification of γH2A.X as a surrogate parameter of direct DNA damage has often been used to assess genotoxicity in plasma-treated cells, whereas no sustainable mutagenic potential of the medical plasma treatment could be identified despite H2A.X phosphorylation. However, phosphorylated H2A.X occurs during apoptosis, which is associated with exposure to cold plasma and ROS. This review summarizes the current understanding of γH2A.X induction and function in oxidative stress in general and plasma medicine in particular. Due to the progress towards understanding the mechanisms of H2A.X phosphorylation in the absence of DSB and ROS, observations of γH2A.X in medical fields should be carefully interpreted.

Role of Glutathione Peroxidases and Peroxiredoxins in Free Radical-Induced Pathologies

In this review, we discuss the pathogenesis of some socially significant diseases associated with the development of oxidative stress, such as atherosclerosis, diabetes, and radiation sickness, as well as the possibilities of the therapeutic application of low-molecular-weight natural and synthetic antioxidants for the correction of free radical-induced pathologies. The main focus of this review is the role of two phylogenetically close families of hydroperoxide-reducing antioxidant enzymes peroxiredoxins and glutathione peroxidases - in counteracting oxidative stress. We also present examples of the application of exogenous recombinant antioxidant enzymes as therapeutic agents in the treatment of pathologies associated with free-radical processes and discuss the prospects of the therapeutic use of exogenous antioxidant enzymes, as well as the ways to improve their therapeutic properties.

The Evidence of the Bystander Effect after Bleomycin Electrotransfer and Irreversible Electroporation

One of current applications of electroporation is electrochemotherapy and electroablation for local cancer treatment. Both of these electroporation modalities share some similarities with radiation therapy, one of which could be the bystander effect. In this study, we aimed to investigate the role of the bystander effect following these electroporation-based treatments. During direct CHO-K1 cell treatment, cells were electroporated using one 100 µs duration square wave electric pulse at 1400 V/cm (for bleomycin electrotransfer) or 2800 V/cm (for irreversible electroporation). To evaluate the bystander effect, the medium was taken from directly treated cells after 24 h incubation and applied on unaffected cells. Six days after the treatment, cell viability and colony sizes were evaluated using the cell colony formation assay. The results showed that the bystander effect after bleomycin electrotransfer had a strong negative impact on cell viability and cell colony size, which decreased to 2.8% and 23.1%, respectively. On the contrary, irreversible electroporation induced a strong positive bystander effect on cell viability, which increased to 149.3%. In conclusion, the results presented may serve as a platform for further analysis of the bystander effect after electroporation-based therapies and may ultimately lead to refined application of these therapies in clinics.

Altered Induction of Reactive Oxygen Species by X-rays in Hematopoietic Cells of C57BL/6-Tg (CAG-EGFP) Mice

Previous work pointed to a critical role of excessive production of reactive oxygen species (ROS) in increased radiation hematopoietic death in GFP mice. Meanwhile, enhanced antioxidant capability was not demonstrated in the mouse model of radio-induced adaptive response (RAR) using rescue of radiation hematopoietic death as the endpoint. ROS induction by ex vivo X-irradiation at a dose ranging from 0.1 to 7.5 Gy in the nucleated bone marrow cells was comparatively studied using GFP and wild type (WT) mice. ROS induction was also investigated in the cells collected from mice receiving a priming dose (0.5 Gy) efficient for RAR induction in WT mice. Significantly elevated background and increased induction of ROS in the cells from GFP mice were observed compared to those from WT mice. Markedly lower background and decreased induction of ROS were observed in the cells collected from WT mice but not GFP mice, both receiving the priming dose. GFP overexpression could alter background and induction of ROS by X-irradiation in hematopoietic cells. The results provide a reasonable explanation to the previous study on the fate of cells and mice after X-irradiation and confirm enhanced antioxidant capability in RAR. Investigations involving GFP overexpression should be carefully interpreted.

Association of Cancer Stem Cell Radio-Resistance Under Ultra-High Dose Rate FLASH Irradiation With Lysosome-Mediated Autophagy

Cancer stem cell (CSC) is thought to be the major cause of radio-resistance and relapse post radiotherapy (RT). Recently ultra-high dose rate “FLASH-RT” evokes great interest for its decreasing normal tissue damages while maintaining tumor responses compared with conventional dose rate RT. However, the killing effect and mechanism of FLASH irradiation (FLASH-IR) on CSC and normal cancer cell are still unclear. Presently the radiation induced death profile of CSC and normal cancer cell were studied. Cells were irradiated with FLASH-IR (∼10⁹ Gy/s) at the dose of 6–9 Gy via laser-accelerated nanosecond particles. Then the ratio of apoptosis, pyroptosis and necrosis were determined. The results showed that FLASH-IR can induce apoptosis, pyroptosis and necrosis in both CSC and normal cancer cell with different ratios. And CSC was more resistant to radiation than normal cancer cell under FLASH-IR. Further experiments tracing lysosome and autophagy showed that CSCs had higher levels of lysosome and autophagy. Taken together, our results suggested that the radio-resistance of CSC may associate with the increase of lysosome-mediated autophagy, and the decrease of apoptosis, necrosis and pyroptosis. To our limited knowledge, this is the first report shedding light on the killing effects and death pathways of CSC and normal cancer cell under FLASH-IR. By clarifying the death pathways of CSC and normal cancer cell under FLASH-IR, it may help us improve the understanding of the radio-resistance of CSC and thus help to optimize the future clinical FLASH treatment plan.