Detection of Glutathione in Oral Squamous Cell Carcinoma Cells With a Fluorescent Probe During the Course of Oxidative Stress and Apoptosis

Assessment of Antioxidant Enzyme Superoxide Dismutase (SOD) in Oral Cancer: Systematic Review and Meta-Analysis

Objective

The present article aims to comprehensively review the existing literature on superoxide dismutase (SOD) levels, an antioxidant enzyme, in oral cancer.

Method

An extensive literature search was conducted across various databases, including PubMed, Wiley Online Library, Science Direct, and Cross Reference, spanning 1998-2023. At the outset, 1,177 articles were initially identified, and 907 studies were excluded due to irrelevance or duplication of the research question. Subsequently, 270 articles underwent screening evaluation, resulting in the selection of 85 articles meeting the inclusion criteria. Following this, 68 articles underwent a full-text comprehensive assessment, and ultimately, 39 were chosen for data extraction. The risk of bias in the designated articles was assessed using the Newcastle-Ottawa Scale. Finally, 13 studies were meticulously selected, offering consistent data for the ensuing meta-analysis. Meta-analysis was executed using comprehensive meta-analysis (CMA) version 3 software (Bio Stat Inc., Englewood, NJ, USA). The meta-analysis findings revealed a statistically significant decrease in SOD levels in both erythrocyte samples (P < 0.001) and tissue samples (P < 0.05) among individuals with oral cancer (OSCC) compared to the normal control group. Conversely, the analysis of three studies on salivary samples demonstrated a significant increase (P < 0.05) in SOD levels in the oral cancer group compared to the healthy controls.

Conclusion

This systematic review underscores a statistically significant decline in SOD levels observed across diverse bio-samples in individuals with oral cancer, indicating an excess of oxidative stress (OS). Additional research is needed to delve into the relationship between SOD levels and clinic-pathological prognostic markers within the oral cancer cohort. Such investigations have the potential to significantly contribute to the development of prognostic tools grounded in OS, thereby guiding strategies for treatment planning.

Development and validation of a minimally invasive protocol for assessing oxidative stress markers in exfoliated oral cells

OBJECTIVES

This study aimed to develop and validate a minimally invasive protocol for characterizing oxidative stress markers in exfoliated oral cells.

MATERIALS AND METHODS

Exfoliated oral cells were collected from healthy volunteers. The protocol included the utilization of specific fluorescent probes to measure intracellular reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨm) and reduced glutathione (GSH). Cells from each volunteer were divided into the positive and negative control groups, which were, respectively, exposed or not to hydrogen peroxide (H2 O2 ) aiming to induce the oxidative stress. Measurements of cell fluorescence were performed using a microscope equipped with epifluorescence.

RESULTS

The results showed that cells exposed to H2 O2 exhibited significantly higher intracellular expression of ROS compared to unexposed cells (positive control: 3851.25 ± 1227.0 vs, negative control: 1106.07 ± 249.6; p = 0.0338). On the contrary, cells exposed to H2 O2 displayed decreased expression of ΔΨm (p = 0.0226) and GSH (p = 0.0289) when compared to the negative control group (ΔΨm positive control: 14634.39 ± 1529.0 vs, negative control: 18897.60 ± 2338.0; and GSH positive control: 9011.08 ± 1900.0 vs, negative control: 15901.79 ± 2745.0).

CONCLUSIONS

The developed protocol proved to be effective in detecting and quantifying oxidative stress biomarkers, such as ROS, ΔΨm and GSH, in exfoliated oral cells. This minimally invasive approach offers a promising method to assess oxidative stress expression and may be clinically relevant in the evaluation of oral diseases associated with oxidative stress.

RICH2 decreases the mitochondrial number and affects mitochondrial localization in diffuse low-grade glioma-related epilepsy

Epilepsy, a common complication of diffuse low-grade gliomas (DLGGs; diffuse oligodendroglioma and astrocytoma collectively), severely compromises the quality of life of patients. DLGG epileptogenicity may primarily be generated by interactions between the tumor and the neocortex. Neuronal uptake of dysfunctional mitochondria from the extracellular environment can lead to abnormal neuronal discharge. Mitochondrial dysfunction is frequently observed in gliomas that can transmigrate across the plasma membranes. Here, we examined the role of the Rho GTPase-activating protein 44 (RICH2) in mitochondrial dynamics and DLGG-related epilepsy. We investigated the association between mitochondrial and RICH2 expression in human DLGG tissues using immunohistochemistry. We examined the association between RICH2 and epilepsy in nude mouse glioma models by electrophysiology. The effect of RICH2 on mitochondrial morphology and calcium motility were assessed by single cell fluorescence microscopy. Quantitative RT-PCR (qRT-PCR) and Western blot analysis were performed to characterize RICH2 induced expression changes in the genes related to mitochondrial dynamics, mitogenesis and mitochondrial function. We found that RICH2 expression was higher in oligodendroglioma than in astrocytoma and was correlated with better prognosis and higher epilepsy rate in patients. The expression of mitochondria may be associated with clinical DLGG-related epilepsy and reduced by RICH2 overexpression. And RICH2 could promote DLGG-related epilepsy in tumorigenic nude mice. RICH2 overexpression decreased calcium flow and the mitochondria released from glioma cells (SW1088 and U251) into the extracellular environment, potentially via downregulation of MFN-1/MFN-2 levels which suggests reduced mitochondrial fusion. In addition, we observed decreased mitochondrial trafficking into neurons (released from glioma cells and trafficked into neurons), which could explain the higher incidence of DLGG-related epilepsy due to reduced neuroprotection. Furthermore, RICH2 downregulated MAPK/ERK/HIF-1 pathway. In conclusion, these results suggest that RICH2 could promote epilepsy by (i) inhibiting mitochondrial fusion via MFN downregulation and Drp-1 upregulation; (ii) altering the MAPK/ERK/Hif-1 signaling axis. RICH2 may be a potential target in the treatment of DLGG-related epilepsy.

Multifunctional carbon dots for glutathione detection and Golgi imaging

Glutathione (GSH) is present in almost every cell in the body and plays various integral roles in many biological processes. The Golgi apparatus is a eukaryotic organelle for the biosynthesis, intracellular distribution, and secretion of various macromolecules; however, the mechanism of GSH in the Golgi apparatus has not been fully elucidated. Here, specific and sensitive sulfur-nitrogen co-doped carbon dots (SNCDs) with orange-red fluorescence was synthesized for the detection of GSH in the Golgi apparatus. The SNCDs have a Stokes shift of 147 nm and excellent fluorescence stability, and they exhibited excellent selectivity and high sensitivity to GSH. The linear response of the SNCDs to GSH was in the range of 10-460 μM (LOD = 0.25 μΜ). More importantly, we used SNCDs with excellent optical properties and low cytotoxicity as probes, and successfully realized golgi imaging in HeLa cells and GSH detection at the same time.

Secretory phospholipase sPLA2-IIAloss impairs tumorigenic and metastatic potential in breast cancer cells

Breast cancer stem cells (BCSCs) are slow cycling cells that escape the traditional chemo-radio-therapy, thereby contributing in resistance and recurrence. Although several markers have been identified, it is still challenging to develop strategies targeting them. In this study, we have isolated BCSCs from MCF-7 cell line using markers CD44+/CD24-/low, which showed higher percentage of mammospheres in CSC population. Moreover, in vivo tumorigenic potential of BCSCs showed as low as 10,000 cells had the ability to develop tumors when transplanted into NOD-SCID mice. We observed an increased level of EMT markers in CSC population. Overexpression of secretory phospholipase sPLA2-IIA was found in CSCs. Further, we have uncovered the upregulation of sPLA2-IIA mediated through JNK signaling in breast cancer cells whereas knockdown of sPLA2-IIA reduces JNK signaling, cell proliferation, EMT and in vivo tumorigenic potential in breast cancer cells. Our study reveals overexpression of sPLA2-IIA in two different breast cancer cells such as MCF7 (ER+,PR+) and a triple negative, MDA-MB-231 (ER-PR-HER2-). Further, the novel role of sPLA2-IIA was discerned by unraveling the molecular mechanism, which regulates the cell proliferation and metastasis in breast cancer cells.

Suspended sediment exacerbates perfluorooctane sulfonate mediated toxicity through reactive oxygen species generation in freshwater clam Corbicula fluminea

Perfluorooctane sulfonate (PFOS) potentially adsorbs on the surface of suspended sediment (SPS), which can develop a toxic "pool" bioavailable to benthic organisms. In this study, the freshwater clam Corbicula fluminea was employed as a zoobenthos model to study the effects of SPS (collected from the Yellow River) on the bioaccumulation and toxicity (from the molecular level to cellular and physiological levels) caused by PFOS exposure. Besides, the enhanced integrated biomarker response (EIBR) system was applied as an index to evaluate the in-depth toxic effects of PFOS and SPS single and co-exposure at various treatment levels. Our results demonstrated that PFOS-SPS co-exposure (at sub-lethal doses of PFOS) significantly increased the bioaccumulation of PFOS, and induced the elevated levels of reactive oxygen species (ROS), the significantly increased activities of superoxide dismutase (SOD) and catalase (CAT) enzymes, the significantly increased content of malondialdehyde (MDA), and the significantly upregulated expression levels of sod, selenium-dependent glutathione peroxidase (se-gpx), heat shock protein 22 (hsp22), heat shock protein 40 (hsp40) and cytochrome P450 30 (cyp30) genes. Further, the co-exposure induced the significantly higher histopathological alterations in the gonads and digestive glands, and even elevated the inhibition of siphoning behavior in clams. In addition, the EIBR index also revealed the highest values for PFOS and SPS co-exposure, compared to the individual SPS or PFOS exposure. The results indicated that at high levels of PFOS exposure (especially at 1000 μg/L), the presence of SPS might increase the generation of ROS by influencing the bioaccumulation of PFOS, which enhanced the toxicity of PFOS to C. fluminea. These results potentially provide basic information for the comprehensive evaluation of the toxic effects of PFOS on benthos in a multi-sediment river ecosystem.

Preincubation with a low-dose hydrogen peroxide enhances anti-oxidative stress ability of BMSCs

Objective

To investigate the effects of low-concentration hydrogen peroxide pretreatment on the anti-oxidative stress of the bone marrow mesenchymal stem cells (BMSCs).

Methods

Rabbit BMSCs were isolated and cultured by density gradient centrifugation combined with the adherence method. Then, the third generation of well-grown BMSCs was continuously treated with 50-μM hydrogen peroxide (H₂O₂) for 8 h as the optimal pretreatment concentration and the BMSCs were continuously applied for 24 h with 500 μM H₂O₂, and the optimal damage concentration was determined as the oxidative stress cell model. The experiment was divided into three groups: control group, high-concentration H₂O₂ injury group (500 μM), and low-concentration H₂O₂ pretreatment group (50 μM + 500 μM). In each group, the DCFH-DA fluorescence probe was used to detect the reactive oxygen species (ROS). ELISA was used to detect the activity of superoxide dismutase (SOD) and catalase (CAT), and the TBA method was used to detect malondialdehyde (MDA). The mitochondrial membrane potential was detected by JC-1. The cell viability was detected by CCK-8 method, while flow cytometry and TUNEL/DAPI double staining were performed to detect cell apoptosis. Hence, the effect of H₂O₂ pretreatment on the anti-oxidative stress of BMSCs was investigated. One-way analysis of variance was performed using SPSS 19.0 statistical software, and P < 0.05 was considered statistically significant.

Results

A large number of typical BMSCs were obtained by density gradient centrifugation and adherent culture. The oxidative stress cell model was successfully established by 500-μM H₂O₂. Compared with the high-concentration H₂O₂ injury group, the low-concentration H₂O₂ pretreatment reduced the production of ROS [(62.33 ± 5.05), P < 0.05], SOD and CAT activities significantly increased (P < 0.05), and MDA levels significantly decreased (P < 0.05). The mitochondrial membrane potential fluorescence changes, the ratio of red/green fluorescence intensity of the high-concentration H₂O₂ injury group was less, and the ratio of the low-concentration H₂O₂ pretreatment group was significantly higher than that. The ratio of red/green increased by about 1.8 times (P < 0.05). The cell viability and survival rate of BMSCs were significantly increased in low-concentration H₂O₂ pretreatment group (P < 0.05), and the cell apoptosis rate was significantly decreased (P < 0.05).

Conclusion

Pretreatment with low-concentration H₂O₂ can enhance the anti-oxidative stress ability and reduce their apoptosis of BMSCs under oxidative stress.