NEK2 affects the ferroptosis sensitivity of gastric cancer cells by regulating the expression of HMOX1 through Keap1/Nrf2.

NEK2 is a serine/threonine protein kinase that is involved in regulating the progression of various tumors. Our previous studies have found that NEK2 is highly expressed in gastric cancer and suggests that patients have a worse prognosis. However, its role and mechanism in gastric cancer are only poorly studied. In this study, we established a model of ferroptosis induced by RSL3 or Erastin in AGS cells in vitro, and konckdown NEK2, HOMX1, Nrf2 by siRNA. The assay kit was used to analyzed cell viability, MDA levels, GSH and GSSG content, and FeRhoNox™-1 fluorescent probe, BODIPY™ 581/591 C11 lipid oxidation probe, CM-H2DCFDA fluorescent probe were used to detected intracellular Fe2+, lipid peroxidation, and ROS levels, respectively. Calcein-AM/PI staining was used to detect the ratio of live and dead cells, qRT-PCR and Western blot were used to identify the mRNA and protein levels of genes in cells, immunofluorescence staining was used to analyze the localization of Nrf2 in cells, RNA-seq was used to analyze changes in mRNA expression profile, and combined with the FerrDb database, ferroptosis-related molecules were screened to elucidate the impact of NEK2 on the sensitivity of gastric cancer cells to ferroptosis. We found that inhibition of NEK2 could enhance the sensitivity of gastric cancer cells to RSL3 and Erastin-induced ferroptosis, which was reflected in the combination of inhibition of NEK2 and ferroptosis induction compared with ferroptosis induction alone: cell viability and GSH level were further decreased, while the proportion of dead cells, Fe2+ level, ROS level, lipid oxidation level, MDA level, GSSG level and GSSG/GSH ratio were further increased. Mechanism studies have found that inhibiting NEK2 could promote the expression of HMOX1, a gene related to ferroptosis, and enhance the sensitivity of gastric cancer cells to ferroptosis by increasing HMOX1. Further mechanism studies have found that inhibiting NEK2 could promote the ubiquitination and proteasome degradation of Keap1, increase the level of Nrf2 in the nucleus, and thus promote the expression of HMOX1. This study confirmed that NEK2 can regulate HMOX1 expression through Keap1/Nrf2 signal, and then affect the sensitivity of gastric cancer cells to ferroptosis, enriching the role and mechanism of NEK2 in gastric cancer.

Thickness-Tunable Growth of Composition-Controllable Two-Dimensional FexGeTe2.

Two-dimensional (2D) magnetic materials provide an ideal platform for investigating novel magnetism and spin behavior in low-dimensional systems while being restricted by the deficiency of accurate bottom-up synthesis. To overcome this difficulty, a facile and universal flux-assisted growth (FAG) method is proposed to synthesize the multicomponent FexGeTe2 (x = 3-5) with different Fe contents and even alloyed with hetero metal atoms. This one-to-one method ensures the stoichiometry consistency from the FexGeTe2 and MyFe5-yGeTe2 (M = Co, Ni) bulk crystal precursors to the 2D nanosheets, with controllable composition. Tuning the growth temperatures can provide thickness-tunable products. Changeable magnetic properties of FexGeTe2 and alloyed CoyFe5-yGeTe2 are substantiated by the superconducting quantum interference device and reflective magnetic circular dichroism. This method generates thickness-tunable high-crystallinity FexGeTe2 samples without phase separation and exhibits a high tolerance to different substrates and a large temperature window, providing a new avenue to synthesize and explore such multicomponent 2D magnets and even the alloyed ones.

Bioinformatics analysis of SOXF family genes reveals potential regulatory mechanism and diagnostic value in cancers.

Background: SOXF family genes (SOX7, SOX17, SOX18) have been reported to involved in tumorigenesis and development in previous articles, separately. But data sources, analysis contents and criteria are not same. Here, we focused on SOXF genes to analyze the regulatory mechanisms and diagnostic value at the same standards. Methods: This study analyzed functions, expressions, methylations, and mutations of SOXF genes through public databases including Metascape, Gene Expression Profiling Interactive Analysis (GEPIA), cBioPortal, Tumor IMmune Estimation Resource (TIMER), and Kaplan-Meier Plotter. TIMER applies a deconvolution method to infer the abundance of tumor-infiltrating immune cells (TIICs) from gene expression profiles. Metascape combines several biological functions and over 40 independent knowledge bases within one integrated portal. GEPIA analyses RNA sequencing expression data from the The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) projects. The cBioPortal visualizes and analyses genetic data from cancer studies. Results: This study found that SOXF genes had low expressions in multiple types of cancer, such as lung cancer and breast cancer (ANOVA differential methods, |log2FC| cutoff: 1, q value cutoff: 0.01). The lung adenocarcinoma (LUAD) patients with high expression of SOX7 [HR =0.72 (0.61-0.85), logrank P=8.1e-05) and SOX17 [HR =0.54 (0.45-0.64), logrank P=1.7e-12] had a higher overall survival (OS) rate. Expression of SOX7 was significantly related to the copy number variation (CNV) (P=3.02e-8) and promoter methylation level (P=5.33e-14), while SOX17 was only related to the promoter methylation level (P=3.32e-12). The expression of SOXF genes was positively correlated with CD4+ T cell infiltration (SOX7: P=8.32e-07, SOX17: P=4.93e-06, SOX18: P=1.61e-11). The AUC for cg07660671 site of SOX7, cg15377283 site of SOX17, and cg24199599 site of SOX18 in distinguishing between normal and tumor in LUAD, intestinal cancer, and breast cancer reached 0.9. SOXF genes were mainly involved in transcriptional regulation, and the Wnt signaling pathway and low expression of SOXF genes in tumor tissue had a strong negative correlation with tumor hypoxia (correlation: -0.35, P≤0.001). Conclusions: This study implied that the expression of SOX7 and SOX17 are potential prognosis markers for patients with Lung cancer and the SOXF genes methylation is potential biomarkers for pan-cancer screening. The SOX7 and SOX17 might modulate the Wnt signaling pathway and the expression of SOXF family genes was significantly negatively correlated with tumor hypoxia.

Hypoxia Activates SOX5/Wnt/ß-Catenin Signaling by Suppressing MiR-338-3p in Gastric Cancer.

MicroRNAs are known to be important in a variety of cancer types. The specific expression and roles of miR-338-3p in the context of gastric cancer, however, remains largely unknown. In this study, we found that miR-338-3p was expressed significantly lower in established/primary human gastric cancer cells than that in human gastric epithelial cells; miR-338-3p is also decreased in human gastric cancer tissues and was positively associated with the worse prognosis of patients with gastric cancer. Enforced expression of miR-338-3p could inhibit cell growth, survival, and proliferation, while inducing cell apoptosis. In addition, miR-338-3p negatively regulated SOX5 expression through directly binding to the 3'-untranslated region of SOX5, and an inverse correlation was found between miR-338-3p and SOX5 messenger RNA expression in gastric cancer tissues. Furthermore, miR-338-3p-induced inactivation of Wnt/ß-catenin signaling was greatly abrogated by SOX5 upregulation. Finally, we found that hypoxic conditions were linked with reduced miR-338-3p expression in the context of gastric cancer. In conclusion, miR-338-3p acts as a tumor suppressor in gastric cancer, possibly by directly targeting SOX5 and blocking Wnt/ß-catenin signaling. These findings might provide novel therapeutic targets for gastric cancer.

Serum biomarker panels for the diagnosis of gastric cancer.

Gastric cancer is a leading cause of mortality due to neoplastic disease. Although early detection of gastric cancers can decrease the mortality rate, it remains a diagnostic challenge because of the lack of effective biomarkers. In this study, fifteen gastric cancer patients and ten healthy subjects were recruited to assess novel serum biomarkers for gastric cancer using antibody microarray technology. ELISA was utilized to validate the antibody array results. As a result, compared to the controls, eleven cytokines were found to be significantly increased in gastric cancer, including interferon gamma receptor 1 (IFNGR1), neurogenic locus notch homolog protein 3 (Notch-3), tumor necrosis factor receptor superfamily member 19L (TNFRSF19L), growth hormone receptor (GHR), signaling lymphocytic activation molecule family 8 (SLAMF8), folate receptor beta (FR-beta), integrin alpha 5, galectin-8, erythropoietin-producing hepatocellular A1 (EphA1), epiregulin, and fibroblast growth factor 12 (FGF-12) with P < 0.05. ELISA validation supported the results of the antibody array. More importantly, most of these eleven cytokines, including IFNGR1, TNFRSF19L, GHR, SLAMF8, FR-beta, and integrin alpha 5 were discovered to be elevated in gastric cancer serum samples for the first time in this study, suggesting that these proteins may serve as novel biomarkers for the early diagnosis and prognosis determination of gastric cancer.