Corilagin induces apoptosis and inhibits autophagy of HL‑60 cells by regulating miR‑451/HMGB1 axis

Corilagin is the primary active component of the Euphorbia phyllanthus plant and has significant anti-cancer properties. However, the biological effects and mechanisms of corilagin on acute myeloid leukemia (AML) have not been clarified. The Cell Counting Kit-8 and Carboxyfluorescein Diacetate Succinimidyl Ester assay results showed that corilagin significantly inhibited proliferation of the AML cell line HL-60 in a time- and dose-dependent manner. Western blotting and flow cytometry analysis were performed to determine the levels of apoptosis in HL-60 cells. The protein levels of cleaved caspase-3 and Bak were upregulated, while Bcl-xl was downregulated in cells treated with corilagin. The percentage of early- and late-stage apoptotic cells increased following corilagin treatment in a dose-dependent manner, indicating that the intrinsic mitochondrial apoptosis pathway was activated by corilagin. Simultaneously, western blotting and immunofluorescence results revealed that autophagy was suppressed; this was accompanied by a decrease in light chain 3-II (LC3-II) conversion and autophagosomes. MicroRNA (miRNA/miR) profile analysis showed that corilagin elevated the expression of the tumor suppressor miR-451, while the mRNA and protein levels of high mobility group protein B1 (HMGB1), the target of miR-451, decreased following exposure to corilagin. Knockdown of miR-451 decreased the downregulation of HMGB1 caused by corilagin, indicating negative regulation of HMGB1 by miR-451 during corilagin treatment. Furthermore, knockdown of miR-451 also attenuated corilagin-induced proliferation inhibition of HL-60 cells, implying that miR-451 was essential for the proliferation inhibitory effect of corilagin. In conclusion, these results indicated that corilagin induced apoptosis and inhibited autophagy in HL-60 cells by regulating the miR-451/HMGB1 axis, and corilagin may be a novel therapeutic drug for the treatment of AML.

Ethyl Pyruvate Alleviates Pulmonary Hypertension through the Suppression of Pulmonary Artery Smooth Muscle Cell Proliferation via the High Mobility Group Protein B1/Receptor for Advanced Glycation End-Products Axis

Purpose: Pulmonary arterial hypertension (PAH) is a formidable disease with no effective treatment at present. With the goal of developing potential therapies, we attempted to determine whether ethyl pyruvate (EP) could alleviate PAH and its mechanism.

Methods: Pulmonary smooth muscle cells were cultured in conventional low-oxygen environments, and cellular proliferation was monitored after treatment with either EP or phosphate-balanced solution (PBS). Expression of high mobility group protein B1 (HMGB1) and receptor for advanced glycation end-products (RAGE) protein were detected by western blot. After hyperkinetic PAH rat models were treated with EP, hemodynamic data were collected. Right ventricular hypertrophy and pulmonary vascular remodeling were evaluated. Expression of HMGB1 and RAGE protein was also detected.

Results: In vitro, proliferative activity increased in low-oxygen environments, but was inhibited by EP treatment. Furthermore, Western blotting showed the decreased expression of HMGB1 and RAGE protein after EP treatment. In vivo, pulmonary artery pressures were attenuated with EP. Right ventricular hypertrophy and pulmonary vascular remodeling were also reversed. Additionally, the expression levels of HMGB1 and RAGE were reduced in lung tissues.

Conclusions: EP can alleviate PAH by suppressing the proliferation of pulmonary artery smooth muscle cells via inhibition of HMGB1/RAGE expression.

miR-142-3p reduces the viability of human cervical cancer cells by negatively regulating the cytoplasmic localization of HMGB1

High mobility group protein B1 (HMGB1) is a nuclear protein that has been reported to contribute to tumor growth in humans. The present study identified a microRNA (miR/miRNA) that targets the 3' untranslated region (3'UTR) of the HMGB1 gene and assessed its effects on the proliferation of human cervical cancer cells and associated molecular mechanism. Western blotting was performed to determine HMGB1 levels in HeLa cells. TargetScan software was used to identify miRNA binding sites adjacent to the HMGB1. The viability of HeLa cells transfected with miR-142-3p mimics or inhibitors was determined using an MTT assay. The subcellular distribution (cytoplasmic or nuclear) of HMGB1 in HeLa cells was observed by western blotting. HMGB1 expression in HeLa and CaSKi cells was significantly higher compared with normal control cervical cells. TargetScan analysis indicated that miR-142-3p binds to the 3'UTR of HMGB1. Transfection with a miR-142-3p inhibitor increased cytoplasmic HMGB1 expression in HeLa cells, as shown by western blot analysis, while transfection with miR-142-3p mimics decreased the cytoplasmic expression of HMGB1 in HeLa cells. Therefore, miR-142-3p negatively regulated HMGB1 levels in cervical cancer cells. These findings indicated that miR-142-3p inhibited the proliferation of human cervical cancer cells, at least in part, by negatively regulating the cytoplasmic localization of HMGB1.

Regulatory Effects of Toll-like Receptor 4 Knockout on CD4+ and CD8+ T Lymphocytes and Interleukin-17 During Myocardial Ischemia

Toll-like receptor 4 (TLR4) is an important cellular transmembrane receptor and pattern-recognition signaling molecule for pathogens in the immune system. High mobility group box 1 protein (HMGB1) plays an important role in myocardial ischemia (MI) and reperfusion through a TLR4-mediated inflammatory response. T lymphocytes are involved in MI injury; however, the specific mechanisms underlying this role remain unclear. In this study, C57BL/6 wild-type (WT) mice and TLR4 knockout mice were divided into three groups, including a normal control group, an MI group that was generated using high doses of isoproterenol (ISO), and an ISO+rHMGB1 group that was generated using a combination of ISO and recombinant HMGB1 (rHMGB1). Echocardiography, hematoxylin and eosin staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and flow cytometry were used to examine each group. The results showed that rHMGB1 could further aggravate myocardial injury and increase the CD4⁺/CD8⁺ ratio and the expression level of interleukin-17 (IL-17) (p<0.05) in vivo After the TLR4 gene was knocked out, myocardial ischemic injury in mice was alleviated, and the CD4⁺/CD8⁺ ratio and IL-17 expression level were both reduced (p<0.05) in vivo. Therefore, TLR4 knockout has a protective effect against MI in mice, which may involve the regulation of the ratio between CD4⁺ and CD8⁺ T lymphocytes and of the IL-17 expression level through the HMGB1-TLR4 signaling pathway.

microRNAs-107 inhibited autophagy, proliferation, and migration of breast cancer cells by targeting HMGB1

PURPOSE

To investigate the effects of microRNAs-107 (miR-107) on autophagy, proliferation, and migration of breast cancer cells and its mechanism by targeting high mobility group protein B1 (HMGB1).

METHODS

Real-time polymerase chain reaction assay was used to detect the expression of miR-107 in breast cancer and its cell lines. In MDA-MB-231 and MDA-MB-453 breast cancer cells, the expression of p62, Beclin1 protein, and the changes of cell proliferation and migration after overexpression of m miR-107 were detected by Western blotting, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and transwell assays. Target Scan online prediction, dual luciferase reporter gene, and Western blot were used to verify the targeting relationship between miR-107 and HMGB1. The effects of silencing HMGB1 expression on p62, Beclin1 protein expression, cell proliferation, and migration ability were detected. The transfected MDA-MB-453 cells were inoculated into the right axilla of the nude mice, the tumor volume and weight were weighed, and the expression of miR-107, HMGB1, p62, and Beclin1 in the tumor were detected.

RESULTS

The expression of miR-107 was downregulated in breast cancer tissues and cell lines (P < 0.01). The expression of p62 protein was upregulated (P < 0.01), while Beclin1 protein was downregulated (P < 0.01) and cell proliferation and migration ability were decreased (P < 0.01) after overexpressing miR-107 in MDA-MB-231 and MDA-MB-453 cells. The results of TargetScan online prediction, dual luciferase reporter gene, and Western blot showed that miR-107 could regulate HMGB1 expression. The expression of p62 protein was upregulated (P < 0.01), while Beclin1 protein was downregulated (P < 0.01) and cell proliferation and migration ability were decreased (P < 0.01) after silencing HMGB1 in MDA-MB-231 and MDA-MB-453 cells. The results of xenograft experiments showed that miR-107 could delay tumor growth and inhibit autophagy.

CONCLUSION

miR-107 could inhibit cell autophagy, proliferation, and migration of breast cancer cells by targeting HMGB1.

HMGB1, TGF-β and NF-κB are associated with chronic allograft nephropathy

The present study aimed to investigate the association between high mobility group protein B1 (HMGB1), transforming growth factor-β1 (TGF-β1), nuclear factor-κB (NF-κB) and chronic allograft nephropathy (CAN) and to identify the clinical significance of HMGB1, TGF-β1, NF-κB on patients with CAN. Between September 2012 and November 2014, 27 patients with CAN diagnosed by biopsy were enrolled in the present study and a further 30 patients that underwent nephrectomy following trauma were selected as the control group. Immunohistochemical staining with HMGB1, TGF-β1 and NF-κB expression in the renal tissues, and western blot analysis were used to measure the relative expression of HMGB1, TGF-β1 and NF-κB. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to estimate the relative expression of HMGB1, TGF-β1 and NF-κB mRNA. Statistical analysis was used to calculate the association between HMGB1, TGF-β1 and NF-κB expression and CAN grade. Immunohistochemical staining demonstrated that HMGB1, TGF-β1 and NF-κB had markedly positive expression rates in renal tubular epithelial cell cytoplasm and membranes in CAN renal tissues, and the positive rates of HMGB1, TGF-β1 and NF-κB increased with the aggravation of CAN pathological grade (I, II and III). The results of western blot analysis indicated that the expression levels of HMGB1, TGF-β1 and NF-κB were significantly higher in the CAN group, compared with the normal group (P<0.05), and the expression levels increased with the progression of CAN grade. A positive association among HMGB1, TGF-β1 and NF-κB expression was identified. RT-qPCR analysis demonstrated that the expression of HMGB1, TGF-β1 and NF-κB mRNA in the CAN group was significantly higher than in the normal group (P<0.05), and the relative expression level of HMGB1, TGF-β1 and NF-κB mRNA not only increased with the aggravation of CAN grade, but was also positively associated with the expression of HMGB1, TGF-β1 and NF-κB, respectively. The abnormal expression of HMGB1, TGF-β1 and NF-κB is therefore, an important manifestation of CAN and the expression of HMGB1, TGF-β1 and NF-κB mRNA in the renal tissues are significantly associated with CAN pathological progression. HMGB1, TGF-β1 and NF-κB may form a signaling pathway that leads to the occurrence of CAN, which induces renal interstitial fibrosis.

Glycyrrhizic acid exerts anti-inflammatory effect to improve cerebral vasospasm secondary to subarachnoid hemorrhage in a rat model

This study aimed to investigate the therapeutic effect of glycyrrhizic acid (GA) on the cerebral vasospasm (CVS) in a rat subarachnoid hemorrhage (SAH) model and to explore the potential mechanism. A total of 44 healthy male rats were randomly assigned into 3 groups: control group (n = 12), SAH group (n = 16) and GA group (n = 16). No treatment was conducted in control group; in SAH group and GA group, experimental CVS was induced using a double-hemorrhage model and then rats were intraperitoneally injected with normal saline and GA at 10 mg/kg, respectively, once daily. Three days later, neurological function was evaluated. Then, animals were sacrificed, and the basilar artery was collected. The inner diameter and vascular wall thickness were determined. Western blotting was employed to detect high mobility group protein B1 (HMGB1) protein expression and RT-PCR to detect the mRNA expression of IL-1β, IL-6, TNF-α, and IL-10 in the basilar artery. GA treatment significantly improved the neurological function following SAH. In GA group, the basilar artery diameter increased markedly and vascular wall thickness reduced significantly when compared with SAH group (p < 0.05). HMGB1 protein expression and mRNA expression of IL-1β, IL-6, TNF-α, and IL-10 in SAH group were significantly higher than in control group (p < 0.05). However, GA dramatically reduced IL-1β, IL-6, and TNF-α, and further elevated IL-10 expression as compared to SAH group (p < 0.05). GA may inhibit HMGB1 expression and subsequent production of inflammatory cytokines to prevent CVS following SAH.

The Role of HMGB1 Signaling Pathway in the Development and Progression of Hepatocellular Carcinoma: A Review

The story of high mobility group protein B1 (HMGB1) in cancer is complicated and the function of HMGB1 in different cancers is uncertain. This review aims to retrieve literature regarding HMGB1 from English electronic resources, analyze and summarize the role of the HMGB1 signaling pathway in hepatocellular carcinoma (HCC), and provide useful information for carcinogenesis and progression of HCC. Results showed that HMGB1 could induce cell proliferation, differentiation, cell death, angiogenesis, metastasis, inflammation, and enhance immunofunction in in vitro and in vivo HCC models. HMGB1 and its downstream receptors RAGE, TLRs and TREM-1 may be potential anticancer targets. In conclusion, HMGB1 plays an important role in oncogenesis and represents a novel therapeutic target, which deserves further study.

Expression of HMGB1 and NF-κB p65 and its significance in non-small cell lung cancer

Aim of the study

To study high mobility group protein B1 (HMGB1) and nuclear transcription factor p65 (NF-κB p65) expression in non-small cell lung cancer and its significance.

Material and methods

106 hospitalized patients with non-small cell lung cancer after thoracic surgery were enrolled; HMGB1 and p65 protein expression was detected by the immunohistochemical method. Semiquantitative expression of HMGB1 and NF-κB p65 was analyzed using Image Pro Plus (IPP) software and statistical analysis.

Results

The rate of HMGB1 positive expression in the non-small cell lung cancer protein B1 family was significantly higher than normal tissues (P < 0.05); p65 protein expression in the non-small cell lung carcinoma group was significantly higher than that of normal tissues (P < 0.05). HMGB1 and NF-κB p65 protein expression was significantly higher compared with the non-metastatic group (P < 0.01). HMGB1 and NF-κB p65 protein expression showed a positive correlation (P < 0.05).

Conclusions

HMGB1 and NF-κB p65 expression may be related to non-small cell lung cancer metastasis.