Diabetes mellitus (DM) is a disease syndrome characterized by chronic hyperglycaemia. A long-term high-glucose environment leads to reactive oxygen species (ROS) production and nuclear DNA damage. Human umbilical cord mesenchymal stem cell (HUcMSC) infusion induces significant antidiabetic effects in type 2 diabetes mellitus (T2DM) rats. Insulin-like growth factor 1 (IGF1) receptor (IGF1R) is important in promoting glucose metabolism in diabetes; however, the mechanism by which HUcMSC can treat diabetes through IGF1R and DNA damage repair remains unclear. In this study, a DM rat model was induced with high-fat diet feeding and streptozotocin (STZ) administration and rats were infused four times with HUcMSC. Blood glucose, interleukin-6 (IL-6), IL-10, glomerular basement membrane, and renal function were examined. Proteins that interacted with IGF1R were determined through coimmunoprecipitation assays. The expression of IGF1R, phosphorylated checkpoint kinase 2 (p-CHK2), and phosphorylated protein 53 (p-p53) was examined using immunohistochemistry (IHC) and western blot analysis. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum levels of 8-hydroxydeoxyguanosine (8-OHdG). Flow cytometry experiments were used to detect the surface markers of HUcMSC. The identification of the morphology and phenotype of HUcMSC was performed by way of oil red \"O\" staining and Alizarin red staining. DM rats exhibited abnormal blood glucose and IL-6/10 levels and renal function changes in the glomerular basement membrane, increased the expression of IGF1 and IGF1R. IGF1R interacted with CHK2, and the expression of p-CHK2 was significantly decreased in IGF1R-knockdown cells. When cisplatin was used to induce DNA damage, the expression of p-CHK2 was higher than that in the IGF1R-knockdown group without cisplatin treatment. HUcMSC infusion ameliorated abnormalities and preserved kidney structure and function in DM rats. The expression of IGF1, IGF1R, p-CHK2, and p-p53, and the level of 8-OHdG in the DM group increased significantly compared with those in the control group, and decreased after HUcMSC treatment. Our results suggested that IGF1R could interact with CHK2 and mediate DNA damage. HUcMSC infusion protected against kidney injury in DM rats. The underlying mechanisms may include HUcMSC-mediated enhancement of diabetes treatment via the IGF1R-CHK2-p53 signalling pathway.
糖尿病是一种以慢性高血糖为特征的疾病综合征，长期的高糖环境会导致活性氧（ROS）的产生和核DNA损伤。人脐带来源的间充质干细胞（HUcMSC）输注2型糖尿病（T2DM）大鼠后可诱导显著的抗糖尿病作用。胰岛素样生长因子1受体（IGF1R）在促进糖尿病患者的葡萄糖代谢中起着重要作用；然而，HUcMSC通过IGF1R和DNA损伤修复治疗糖尿病的机制尚不清楚。本研究经高脂饮食喂养和链脲佐菌素（STZ）给药诱导建立糖尿病大鼠模型，并给大鼠输注四次HUcMSC，随后检测血糖、白细胞介素-6（IL-6）、IL-10、肾小球基底膜和肾功能。通过共免疫沉淀测定与IGF1R相互作用的蛋白质；使用免疫组织化学（IHC）和蛋白质印迹分析检测IGF1R、磷酸检查点激酶2（p-CHK2）和p-p53的表达；采用酶联免疫吸附试验（ELISA）测定血清8-羟基脱氧鸟苷（8-OHdG）的水平；使用流式细胞术检测HUcMSC的表面标志物；采用油红O染色和茜素红染色鉴定HUcMSC的形态和表型。结果显示：糖尿病大鼠肾小球基底膜、血糖、IL-6/10水平和肾功能异常；胰岛素样生长因子1（IGF1）和IGF1R表达增加；IGF1R与CHK2相互作用；p-CHK2在IGF1R敲低细胞中的表达显著降低。当使用顺铂诱导DNA损伤时，p-CHK2的表达高于未经顺铂诱导的IGF1R敲低组。HUcMSC的输注改善了糖尿病大鼠的血糖异常，并保护了其肾脏结构和功能。糖尿病组IGF1、IGF1R、p-CHK2和p-p53的表达以及8-OHdG的水平与对照组相比显著增加，且在HUcMSC治疗后降低。综上所述，IGF1R可以与CHK2相互作用并介导DNA损伤，且HUcMSC对糖尿病大鼠肾损伤有保护作用。HUcMSC通过介导IGF1R-CHK2-p53信号通路是治疗糖尿病的潜在机制。.

BACKGROUND: This study investigated the impact of salvianolic acids, derived from Danshen, on melanoma cell growth. Specifically, we assessed the ability of salvianolic acid A (Sal A) to modulate melanoma cell proliferation.
METHODS: We used human melanoma A2058 and A375 cell lines to investigate the effects of Sal A on cell proliferation and death by measuring bromodeoxyuridine incorporation and lactate dehydrogenase release. We assessed cell viability and cycle progression using water soluble tetrazolium salt-1 (WST-1) mitochondrial staining and propidium iodide. Additionally, we used a phospho-kinase array to investigate intracellular kinase phosphorylation, specifically measuring the influence of Sal A on checkpoint kinase-2 (Chk-2) via western blot analysis.
RESULTS: Sal A inhibited the growth of A2058 and A375 cells dose-responsively and induced cell cycle arrest at the G2/M phase. Notably, Sal A selectively induces Chk-2 phosphorylation without affecting Chk-1, thereby degrading Chk-2-regulated genes Cdc25A and Cdc2. However, Sal A does not affect the Chk1-Cdc25C pathway.
CONCLUSIONS: Salvianolic acids, especially Sal A, effectively hinder melanoma cell growth by inducing Chk-2 phosphorylation and disrupting G2/M checkpoint regulation.

OBJECTIVE: Long non-coding RNAs (lncRNAs) play an important role in tumor progression, including in hepatocellular carcinoma (HCC) induced by hepatitis B virus (HBV). Therefore, the aim of this study was to investigate the role of LINC02532 in HCC, mainly for diagnostic prognostic value and cellular function, as well as mechanistic aspects.
METHODS: Initially, GEO and VirBase databases were used to screen for aberrant lncRNAs in HBV-HCC.Then, HBV-HCC persons followed up in our center were retrospectively studied to investigate the diagnostic, prognostic value of LINC02532 in HBV-HCC. Subsequently, the role of LINC02532 in HBV-HCC was measured using cellular function assay methods and possible mechanisms were analyzed in conjunction with bioinformatic predictive science.
RESULTS: LINC02532 was a lncRNA abnormally expressed in HBV-HCC. LINC02532 was significantly up-regulated in the expression level in HBV-HCC tissues compared with normal tissues from patients. Moreover, LINC02532 could distinguish HBV-HCC and predict the prognosis of HBV-HCC. In vitro experiments showed that LINC02532 could regulate miR-455-3p and promote the malignant characterization of HBV-HCC cells. CHEK2 was a target gene of miR-455-3p.
CONCLUSIONS: The prognosis and diagnosis of HBV-HCC can rely on the expression of LINC02532. LINC02532 was important for further progression of HBV-HCC, by moderating miR-455-3p/CHEK2.

p53 regulates multiple signaling pathways and maintains cell homeostasis under conditions of DNA damage and oxidative stress. Although USP7 has been shown to promote p53 stability via deubiquitination, the USP7-p53 activation mechanism has remained unclear. Here, we propose that DNA damage induces reactive oxygen species (ROS) production and activates ATM-CHK2, and CHK2 then phosphorylates USP7 at S168 and T231. USP7 phosphorylation is essential for its deubiquitination activity toward p53. USP7 also deubiquitinates CHK2 at K119 and K131, increasing CHK2 stability and creating a positive feedback loop between CHK2 and USP7. Compared to peri-tumor tissues, thyroid cancer and colon cancer tissues show higher CHK2 and phosphorylated USP7 (S168, T231) levels, and these levels are positively correlated. Collectively, our results uncover a phosphorylation-deubiquitination positive feedback loop involving the CHK2-USP7 axis that supports the stabilization of p53 and the maintenance of cell homeostasis.

In the meiotic prophase, programmed DNA double-strand breaks are repaired by meiotic recombination. Recombination-defective meiocytes are eliminated to preserve genome integrity in gametes. BRCA1 is a critical protein in somatic homologous recombination, but studies have suggested that BRCA1 is dispensable for meiotic recombination. Here we show that BRCA1 is essential for meiotic recombination. Interestingly, BRCA1 also has a function in eliminating recombination-defective oocytes. Brca1 knockout (KO) rescues the survival of Dmc1 KO oocytes far more efficiently than removing CHK2, a vital component of the DNA damage checkpoint in oocytes. Mechanistically, BRCA1 activates chromosome asynapsis checkpoint by promoting ATR activity at unsynapsed chromosome axes in Dmc1 KO oocytes. Moreover, Brca1 KO also rescues the survival of asynaptic Spo11 KO oocytes. Collectively, our study not only unveils an unappreciated role of chromosome asynapsis in eliminating recombination-defective oocytes but also reveals the dual functions of BRCA1 in safeguarding oocyte genome integrity.

Immune checkpoint blockade (ICB) therapy has improved treatment effects in multiple cancers. Gene mutations in the DNA damage repair pathway (DDR) may cause genomic instability and may relate to the efficacy of ICB. Checkpoint kinase 2 (CHEK2) and polymerase epsilon (POLE) are important genes in the DDR. In this study, we aimed to study the impact of CHEK2 deficiency mutations on the response to ICB. We found that tumors with CHEK2 mutations had a significantly higher tumor mutational burden (TMB) compared to those with CHEK2-WT in a pancancer database. We noted that CHEK2 deficiency mutations potentiated the anti-tumor effect of anti-PD-1 therapy in MC38 and B16 tumor-bearing mice with the decrease of tumor volume and tumor weight after anti-PD-1 treatment. Mechanistically, CHEK2 deficiency tumors were with the increased cytotoxic CD8+ T-cell infiltration, especially cytotoxic CD8+ T cells, and modulated the tumor-immune microenvironment with an upregulated immune inflammatory pathway and antigen presentation pathway after anti-PD-1 treatment. Furthermore, murine models with POLE mutations confirmed that CHEK2 deficiency shaped similar mutational and immune landscapes as POLE mutations after anti-PD-1 treatment. Taken together, our results demonstrated that CHEK2 deficiency mutations may increase the response to ICB (eg. anti-PD-1) by influencing the tumor immune microenvironment. This indicated that CHEK2 deficiency mutations were a potentially predictive biomarker and CHEK2 deficiency may potentiate response to immunotherapy.

Checkpoint kinase 2 (CHEK2) plays a crucial role in responding to DNA damage and is linked to diverse cancer types. However, its significance in the prediction of prognosis and impacts on the immune status of clear cell renal cell carcinoma (ccRCC) remains unclear. This study aimed to identify the role of CHEK2 in prognosis and immune microenvironment of ccRCC. We analyzed transcriptome and clinicopathological data from the cancer genome atlas (TCGA) database and conducted functional enrichment analysis to explore molecular mechanisms. The relationship between CHEK2 and immune infiltration was evaluated, and drug sensitivity analysis was performed using the CellMiner database. The results showed that CHEK2 was an independent predictor of ccRCC prognosis and was closely associated with immune-related processes. Additionally, high expression of CHEK2 was linked to resistance to certain targeted drugs. These findings suggest that CHEK2 could serve as a biomarker for ccRCC, providing insights into tumor immune microenvironment alterations and immunotherapeutic response. Further investigation is needed to fully understand the potential of CHEK2 as a prognostic predictor and therapeutic target for ccRCC.

Individual genetic background can play an essential role in determining the development of esophageal squamous cell carcinoma (ESCC). PTPN13 and CHEK2 play important roles in the pathogenesis of ESCC. This case-control study aimed to analyze the association between gene polymorphisms and ESCC susceptibility.
DNA was extracted from the peripheral blood of patients. The Agena MassARRAY platform was used for the genotyping. Statistical analysis was conducted using the chi-squared test or Fisher\'s exact test, logistic regression analysis, and stratification analysis.
The \'G\' allele of rs989902 (PTPN13) and the \'T\' allele of rs738722 (CHEK2) were both associated with an increased risk of ESCC (rs989902: OR = 1.23, 95% CI = 1.02-1.47, p = 0.028; rs738722: OR = 1.28, 95% CI = 1.06-1.55, p = 0.011). Stratification analysis showed that SNPs (rs989902 and rs738722) were notably correlated with an increased risk of ESCC after stratification for age, sex, smoking, and drinking status. In addition, rs738722 might be associated with lower stage, while rs989902 had a lower risk of metastasis.
Our findings display that PTPN13 rs989902 and CHEK2 rs738722 are associated with an increased risk of ESCC in the Chinese Han population.

DNA damage of neurons is accumulated in Alzheimer\'s disease (AD). DNA damage-activated Checkpoint kinase 2 (CHEK2) is evaluated in Aβ-treated Neuro2a APPSwe/Δ9 cells, and the miR-669b-5p was specifically down-regulated. However, the underlying molecular mechanism between CHEK2 and miR-669b-5p in Neuro2a APPSwe/Δ9 cells remains unclear. This research discovers that in A-treated Neuro2a APPSwe/Δ9 cells, CHEK2 expression and miR-669b-5p expression were inversely correlated. In addition, miR-669b-5p mimics increased cell survival and proliferation in Neuro2a APPSwe/Δ9 cells while decreasing the production of inflammatory cytokines and cell death. Furthermore, it is observed that CHEK2 was a miR-669b-5p downstream target gene and that CHEK2 restored the miR-669b-5p\'s functions. According to this research, miR-669b-5p is a potential therapy for Alzheimer\'s patients since it slows the advancement of the disease.

BACKGROUND: Solitary rectal ulcer syndrome (SRUS) is a rare rectal disease with unknown etiology. Data on the genetic background in SRUS is lacking.
METHODS: Here, we report the first case of SRUS in a mother-son relationship. Gene sequencing was conducted on the whole family, which revealed an inherited CHEK2 p.H371Y mutation. The experiment preliminarily revealed that the CHEK2 mutation did not affect the expression of CHEK2 protein, but affected the function of CHEK2, resulting in the expression level changes of downstream genes such as CDC25A.
CONCLUSIONS: SRUS is a genetic susceptibility disease where CHEK2 p.H371Y mutation may play a crucial role in the development and prognosis of SRUS.