EGR-1 plays a protective role in AMPK inhibitor compound C-induced apoptosis through ROS-induced ERK activation in skin cancer cells

Role of reactive oxygen species in regulating epigenetic modifications

Reactive oxygen species (ROS) originate from diverse sources and regulate multiple signaling pathways within the cellular environment. Their generation is intricately controlled, and disruptions in their signaling or atypical levels can precipitate pathological conditions. Epigenetics, the examination of heritable alterations in gene expression independent of changes in the genetic code, has been implicated in the pathogenesis of various diseases through aberrant epigenetic modifications. The significant contribution of epigenetic modifications to disease progression underscores their potential as crucial therapeutic targets for a wide array of medical conditions. This study begins by providing an overview of ROS and epigenetics, followed by a discussion on the mechanisms of epigenetic modifications such as DNA methylation, histone modification, and RNA modification-mediated regulation. Subsequently, a detailed examination of the interaction between ROS and epigenetic modifications is presented, offering new perspectives and avenues for exploring the mechanisms underlying specific epigenetic diseases and the development of novel therapeutics.

Early growth response 1 regulates dual‑specificity protein phosphatase 1 and inhibits cell migration and invasion of tongue squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumors in the head and neck, and among the OSCCs, tongue squamous cell carcinoma (TSCC) is one of the most common types. Although therapy strategies have recently advanced, the prognosis of TSCC has not substantially improved. Metastasis is one of the main causes of patient mortality in TSCC; therefore, it is necessary to elucidate the mechanism by which TSCC metastasis is regulated. In the present study, the early growth response 1 (Egr-1) expression in TSCC was analyzed based on GEO datasets and the effect of Egr-1 in TSCC tumor cell migration and invasion was measured using Transwell assay. By overexpressing dual-specificity protein phosphatase 1 (DUSP1) in cells with Egr-1 knockdown using lentivirus infection, the role of DUSP1 in Egr-1-regulated TSCC cell migration and invasion was determined. By using luciferase and ChIP assays, the mechanism behind how DUSP1 is regulated by Egr-1 was detected. In the present study, it was demonstrated that Egr-1 was downregulated in TSCC and the knockdown of Egr-1 increased TSCC cell migration and invasion. The expression of Egr-1 was also correlated with DUSP1. The overexpression of DUSP1 in Egr-1 knockdown cells, reduced the level of cell migration and invasion. Furthermore, it was demonstrated that knockdown of Egr-1 inhibited the promoter activity of DUSP1 and the site through which Egr-1 regulates DUSP1 transcription was identified. In conclusion, the present study demonstrated that Egr-1 regulates TSCC cell migration and invasion through modulating DUSP1, suggesting the potential of Egr-1 and DUSP1 as therapy targets for TSCC.

Gemcitabine resistance in non-small cell lung cancer is mediated through activation of the PI3K/AKT/NF-κB pathway and suppression of ERK signaling by reactive oxygen species

Lung cancer is one of the most common cancers in the world. Chemotherapy is a standard clinical treatment. However, tumor cells often develop multidrug resistance after chemotherapy, an inevitable bottleneck in cancer treatment. Therefore, this study used gemcitabine-resistant (GEM-R) CL1-0 lung cancer cells. First, we used flow cytometry and western blot analysis to examine differences in performance between resistant and parental cells. The results showed that compared with parental cells, GEM-R CL1-0 cells significantly enhanced the activation of the AKT pathway, which promoted survival and growth, and decreased the activation of the reactive oxygen species-extracellular signal-regulated kinase (ROS)-ERK pathway. Next, the AKT and ERK pathways' role in tumor growth was further explored in vivo using a xenograft model. The results showed that enhancing AKT and inhibiting ERK activation reduced GEM-induced inhibition of tumor growth. Finally, combining the above results, we found that GEM-R CL1-0 cells showed reduced sensitivity to GEM by activating the phosphatidylinositol 3-kinase/AKT/NF-kB pathway and inhibiting the ROS-ERK pathway leading to resistance against GEM. Therefore, the AKT and ERK pathways are potential targets for improving the sensitivity of cancer cells to anticancer drugs.

The role and function of CLU in cancer biology and therapy

Clusterin (CLU) is a highly evolutionary conserved glycoprotein with multiple isoform-specific functions and is widely distributed in different species. Accumulated evidence has shown the prominent role of CLU in regulating several essential physiological processes, including programmed cell death, metastasis, invasion, proliferation and cell growth via regulating diverse signaling pathways to mediate cancer progression in various cancers, such as prostate, breast, lung, liver, colon, bladder and pancreatic cancer. Several studies have revealed the potential benefit of inhibiting CLU in CLU inhibition-based targeted cancer therapies in vitro, in vivo or in human, suggesting CLU is a promising therapeutic target. This review discusses the multiple functions and mechanisms of CLU in regulating tumor progression of various cancers and summarizes the inhibitors of CLU used in CLU inhibition-based targeted cancer therapies.

Gastrodin inhibits high glucose‑induced inflammation, oxidative stress and apoptosis in podocytes by activating the AMPK/Nrf2 signaling pathway

Diabetic nephropathy (DN) is a serious and common complication of type 1 and 2 diabetes. Gastrodin has been reported to suppress high glucose (HG)-induced inflammation and oxidative stress in vivo and in vitro. However, the effect of gastrodin on DN has not been fully elucidated. The present study aimed to investigate the underlying mechanism involved in the effect of gastrodin on podocyte injury caused by DN. Cell viability was evaluated using Cell Counting Kit-8 assay and secretion levels of TNF-α, IL-1β and IL-6 were measured using ELISA. The levels of malondialdehyde, activities of lactate dehydrogenase and superoxide dismutase were quantified using corresponding assay kits. Additionally, cell apoptosis was analyzed by TUNEL assay, whilst protein expressions related to inflammation, apoptosis and the 5'-AMP-activated protein kinase (AMPK)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway were measured by western blot analysis. The results showed that gastrodin increased the viability of MPC5 cells following HG stimulation. Gastrodin also alleviated HG-induced inflammation, oxidative stress and apoptosis in MPC5 cells. Furthermore, gastrodin promoted activation of the AMPK/Nrf2 pathway in MPC5 cells. Treatment with the AMPK inhibitor, compound C, reversed the inhibitory effects of gastrodin on inflammation, oxidative stress and cell apoptosis. To conclude, treatment of MPC5 cells with gastrodin can attenuate HG-induced inflammation, oxidative stress and cell apoptosis by activating the AMPK/Nrf2 signaling pathway. Results from the current study suggest that gastrodin can be used as an effective therapeutic agent against HG-induced podocyte injury in DN.

Comprehensive analysis of differentially expressed genes reveals the promotive effects of UBE2T on colorectal cancer cell proliferation

Colorectal cancer (CRC) is one of the most common malignancies worldwide. Via analysis using The Cancer Genome Atlas database, the present study identified 1,835 genes that were differentially expressed in CRC, including 811 upregulated and 1,024 downregulated genes. Enrichment analyses using the Database for Annotation, Visualization and Integrated Discovery tool revealed that these differentially expressed genes were associated with the regulation of CRC progression by modulating multiple pathways, such as ‘Cell Cycle, Mitotic’, ‘DNA Replication’, ‘Mitotic M-M/G1 phases’ and ‘ATM pathway’. To identify the key genes in CRC, protein-protein interaction (PPI) network analysis was performed and the hub modules in upregulated and downregulated PPI networks were identified. Ubiquitin-conjugating enzyme E2 T (UBE2T), a member of the E2 family, was identified to be a key regulator in CRC. To the best of our knowledge, the present study was the first to demonstrate that UBE2T expression was upregulated in CRC samples compared with normal tissues. Kaplan-Meier analysis revealed that higher expression levels of UBE2T were associated with worse prognosis compared with lower UBE2T expression levels in CRC. Additionally, the present study demonstrated that knockdown of UBE2T inhibited CRC cell proliferation. Flow cytometry assays revealed that UBE2T knockdown induced cell cycle arrest at G₁ phase and apoptosis in vitro. These results suggested that UBE2T may be a novel potential biomarker for CRC.

S14G-humanin (HNG) protects retinal endothelial cells from UV-B-induced NLRP3 inflammation activation through inhibiting Egr-1

UV-B stimulation can induce retinopathy, whose pathogenesis is currently unclear. UV-B mediated inflammation in retinal endothelial cells is reported to be involved in the pathogenesis of retinopathy. S14G-humanin (HNG) is a neuroprotective peptide that has recently been reported to exert significant anti-inflammatory effects and protective properties against cell death. The present study aims to investigate the protective effects of HNG against UV-B-challenged retinal endothelial cells and explore the underlying mechanism. UV-B radiation was used to induce an injury model in human retinal endothelial cells (HRECs). First, exposure to UV-B induced the expression of TXNIP. Additionally, we found that treatment with HNG inhibited the activation of the TXNIP/NLRP3 signaling pathway and mitigated the excessive release of IL-1β and IL-18 in UV-B-challenged HRECs. UV-B increased the expression of the transcriptional factor endothelial growth response-1 (Egr-1). Interestingly, overexpression of Egr-1 increased the luciferase activity of the TXNIP promoter as well as the mRNA and protein expression of TXNIP. In contrast, the knockdown of Egr-1 reduced the expression of TXNIP under both the normal and UV-B exposure conditions. Importantly, treatment with HNG attenuated UV-B-induced expression of Egr-1. However, overexpression of Egr-1 abolished the inhibitory effects of HNG-induced activation of NLRP3 as well as the production of IL-1β and IL-18. Taken together, our findings reveal that HNG protected retinal endothelial cells from UV-B-induced NLRP3 inflammation activation through inhibiting TXNIP mediated by Egr-1.

Antimicrobial peptide 17BIPHE2 inhibits the proliferation of lung cancer cells in vitro and in vivo by regulating the ERK signaling pathway

In 2018, there were 18.1 million new cancer cases and 9.6 million cancer-related deaths worldwide, among which the incidence rate of lung cancer (11.6%) and fatality rate (18.4%) both ranked first. The antimicrobial peptide LL-37 is an important component of the natural immune system and possesses several biological properties, including antibacterial, antiviral and anticancer effects. The antimicrobial peptide 17BIPHE2, the shortest synthetic peptide derivative of LL-37, exhibits biological activities similar to those of LL-37. The objective of the present study was to investigate the mechanism of action of exogenous 17BIPHE2 against lung cancer cells. The human lung adenocarcinoma cell line A549 was treated with 17BIPHE2. Changes in cell proliferation, migration, invasion, mitochondrial membrane potential (ΔΨm), and the levels of reactive oxygen species (ROS), Ca2+ and apoptosis-related proteins, including BAX, BCL-2 and ERK, were detected using flow cytometry, transmission electron microscopy and western blotting. The results showed that 17BIPHE2 significantly increased the apoptosis rate of A549 cells and elevated BAX expression, ERK phosphorylation, and ROS and Ca2+ levels, but decreased the expression of BCL-2, ERK and Ki67. In addition, the peptide reduced ΔΨm and the cell migration ability of A549 cells and inhibited tumor growth. ERK inhibition significantly attenuated the anticancer effect of 17BIPHE2. The present observations suggested that 17BIPHE2 can effectively inhibit cancer cells by regulating the ERK signaling pathway.