Global trends in PANoptosis research: bibliometrics and knowledge graph analysis.

PANoptosis has recently been discovered as a new type of cell death. PANoptosis mainly refers to the significant interaction among the three programmed cell death pathways of apoptosis, necroptosis, and pyroptosis. Despite this, only a few studies have examined the systematic literature in this area. By analyzing the bibliometric data for PANoptosis, we can visualize the current hotspots and predicted trends in research. This study analyzed bibliometric indicators using the Histcite Pro 2.0 tool, which searches the Web of Science for PANoptosis literature published between 2016 and 2022. A bibliometric analysis was performed using Histcite Pro 2.0, while research trends and hotspots were visualized using VOSviewer, CiteSpace and BioBERT. The output of related literature was low in the four years from the first presentation of PANoptosis in 2016 to 2020. The volume of relevant literature grew exponentially between 2020 and 2022. The United States and China play a leading role in this field. Although China started late, its research in this field is developing rapidly. As research progressed, more focus was placed on the relationship between PANoptosis and pyroptosis, as well as apoptosis and necrosis. Now is a rapid development stage of PANoptosis research. Most of the research focuses on the cellular level, and the focus is more on the treatment of tumor-related diseases. The current focus of this area is PANoptosis mechanisms in cancer and inflammation. It can be seen from the burst analysis of keywords that caspase1 and host defense have consistently been research hotspots in the field of PANoptosis, while the frequency of NLRC4, causes of autoinflammation, recognition, NLRP3, and Gasdermin D has gradually increased, all of which have become research hotspots in recent years. Finally, we used the BioBERT biomedical language model to mine the most documented genes and diseases in the PANoptosis field articles, pointing out the direction for subsequent research steps. According to a bibliometric analysis, researchers have shown an increased interest in PANoptosis over the past few years. Researchers initially focused on the molecular mechanism of PANoptosis and pyroptosis, apoptosis, and necroptosis. The role of PANoptosis in diseases and conditions such as inflammation and tumors is one of the current research hotspots in this area. The focus is more on treating inflammation-related diseases, which will become the key development direction of future research.

The Impact of Specialized Knowledge Search on Enterprise Innovation.

Against the backdrop of the fierce competition in the market nowadays, a closed innovation model based on internal knowledge is no longer sufficient to support enterprises in search of high-performance innovation. Instead, corporations are desperately required to search for resources of external knowledge to meet their innovation goals. Existing studies on open innovation in corporate management failed to fully elaborate on the mechanism of how the external knowledge search could impose an impact on sustaining innovation and disruptive innovation. In this study, the external knowledge search was divided into three categories according to the knowledge-based theory, namely, the scientific knowledge search, the market knowledge search, and the supply-chain knowledge search. While taking into account the moderating role of the focus of attention of the manager, we analyzed the statistical results of 485 questionnaires collected from manufacturing enterprises to elaborate on the mechanism of how the specialized knowledge search could impose an impact on sustaining innovation and disruptive innovation. Our research conclusions are expected to enrich existing studies on the factors contributing to corporate innovation, including but not limited to sustaining innovation and disruptive innovation. In addition, the research findings are expected to lay an empirical foundation by summarizing previous theoretical opinions while providing references for subsequent in-depth studies in the meantime. Moreover, the paper has put forward practical management measures and suggestions that could enable enterprises in developing countries to search and effectively transform the external knowledge into innovative outcomes. Last but not least, this study is expected to provide both theoretical and practical guidance for enterprises to further facilitate innovation by means of knowledge search.

CXCR4 promotes gefitinib resistance of Huh7 cells by activating the c-Met signaling pathway.

C-X-C chemokine receptor type 4 (CXCR4) expression is associated with poor prognosis of hepatocellular carcinoma (HCC). The aim of this study was to explore the biological role of CXCR4 in gefitinib resistance of HCC. Compared with a normal, non-gefitinib-resistant, human HCC cell line (Huh7), CXCR4 mRNA and protein were highly expressed in gefitinib-resistant Huh7 cells (Huh7-R). Cell proliferation was decreased, and apoptosis was enhanced in Huh7 cells in the presence of gefitinib. These influences conferred by gefitinib treatment on proliferation and apoptosis of Huh7 cells were abolished by CXCR4 overexpression. CXCR4 knockdown reduced the proliferation ability of HuH-7R cells after gefitinib treatment. Importantly, CXCR4 overexpression had no influence on caveolin 1 (Cav-1) expression; similarly, Cav-1 silencing did not cause a substantive change in CXCR4 expression. However, CXCR4 activated Cav-1, c-Met, and Raf-1 in Huh7 cells, whereas Cav-1 silencing repressed the expression of Raf-1 and phosphorylated c-Met in Huh7 cells. CXCR4 overexpression promoted proliferation and repressed apoptosis in gefitinib-treated Huh7 cells, which was partly rescued by PHA-665752 (a c-Met inhibitor) treatment or c-Met deficiency. Finally, we constructed a tumor xenograft model to determine the influence of CXCR4 overexpression on tumor growth of HCC. CXCR4 overexpression accelerated tumor growth of HCC, which was abrogated by c-Met deficiency. These findings demonstrate that CXCR4 overexpression activates c-Met via the Cav-1 signaling pathway, thereby promoting gefitinib resistance of Huh7 cells. Thus, this study highlights novel insights into the mechanism of gefitinib resistance of HCC and CXCR4 may become a potential target for HCC treatment.

Development of an amplified luminescent proximity homogeneous assay for the detection of sulfonamides in animal-derived products.

In this study, we carried out an amplified luminescent proximity homogeneous assay (AlphaLISA) to detect sulfonamides (SAs) antibiotic residues in plasma, milk, pork, chicken, and fish. The SAs AlphaLISA method can detect 13 SAs with half-inhibitory concentration (IC50) 2.11-29.77 ng/ml. The detection level of those SAs was 0.3-41.12 ng/ml in matrices, which satisfied the maximum residue limit (MRL) of the European Union, United States, and China. Our recoveries are in the range of 88% to 116.8% with a coefficient of variation less than 9.3% for different spiked food samples. We observed a good correlation between the AlphaLISA and liquid chromatography-tandem mass spectrometry (LC-MS/MS) with blood samples from injected rabbits. The established AlphaLISA method provided a no-washing, rapid, high-throughput screening tool for SAs in food quality control, which is suitable for small-volume samples.

MiR-155 aggravates impaired autophagy of pancreatic acinar cells through targeting Rictor.

The aim of this study was to investigate the role and mechanism of miR-155 in regulating autophagy in a caerulein-induced acute pancreatitis (AP) cellular model. GFP-LC3 immunofluorescence assay was performed to detect autophagy vesicle formation in pancreatic acinar cell line AR42J. AR42J cells were transfected with miR-155 mimic, inhibitor, and corresponding controls to explore the effect of miR-155 on autophagy. The protein levels of LC3-I, LC3-II, Beclin-1, and p62 were analyzed by western blot analysis. Dual-luciferase reporter assay was performed to verify the interaction between miR-155 and Rictor (RPTOR independent companion of MTOR complex 2). The results showed that caerulein treatment induced impaired autophagy as evidenced by an increase in the accumulation of p62 together with LC3-II in AR42J cells, accompanied by miR-155 upregulation. Furthermore, miR-155 overexpression aggravated, whereas miR-155 silencing reduced the caerulein-induced impairment of autophagy. Mechanistically, Rictor was confirmed to be a direct target of miR-155, which could rescue the miR-155 overexpression-mediated aggravation of impaired autophagy. Collectively, these findings indicate that miR-155 aggravates impaired autophagy in caerulein-treated pancreatic acinar cells by targeting Rictor.

miR­92a­3p regulates trypsinogen activation via Egr1 in AR42J cells.

Acute pancreatitis (AP) exhibits high morbidity and mortality rates. The onset of AP is characterized by early trypsinogen activation.The present study aimed to investigate the expression of microRNA (miR)­92a­3p and early growth response protein 1 (Egr1), and the effect of miR­92a­3p on trypsinogen activation in the pancreatic exocrine cell line AR42J. mRNA and miRNA microarrays were used to identify differentially expressed mRNAs and miRNAs in AR42J cells. A miRNA­mRNA network was constructed using bioinformatics software, and Egr1 and its regulated miRNA subnetworks were identified by reviewing previous literature. The results suggested that miR­92a­3p could bind to Egr1 3'untranslated region sequence. Subsequently, miR­92a­3p mimic and inhibitor were used to transfect AR42J cells. Following transfection, reverse transcription­quantitative PCR and western blotting were performed to detect Egr1 expression. Furthermore, AR42J cells were cotransfected with miR­92a­3p inhibitor and small interfering (si)­Egr1. The trypsinogen activation rate of AR42J cells was measured by flow cytometry. Microarrays and bioinformatics results indicated that Egr1 may be a target gene of miR­92a­3p. In addition, the present study suggested that miR­92a­3p downregulated Egr1 in vitro and that miR­92a­3p and Egr1 expression was associated with trypsinogen activation. Furthermore, miR­92a­3p inhibitor reversed the effect of si­Egr1 on trypsinogen activation. In conclusion, miR­92a­3p may negatively regulate the activation of trypsinogen in AR42J cells via Egr1.

Research on the Effects of Entrepreneurial Education and Entrepreneurial Self-Efficacy on College Students' Entrepreneurial Intention.

Entrepreneurship is one of the important engines of economic development. Under the influence of policy encouragement and economic situation, college students have become the emerging entrepreneurial subjects. Studying the factors influencing their willingness to innovate is conducive to improving the entrepreneurial status and performance. From the perspective of planned behavior theory, this paper analyzes the effects of college students' entrepreneurship education and self-efficacy on their entrepreneurial intention. Using a sample of 327 college students in China, we test the hypotheses, and get some results. Firstly, college students' entrepreneurial education has a significant positive effect on their entrepreneurial intention, but has no obvious effect on the entrepreneurial attitude. Secondly, college students' entrepreneurial self-efficacy has a significant positive effect on the entrepreneurial attitude and entrepreneurial intention, and the entrepreneurial attitude plays a partial intermediary role in the relationship between entrepreneurial self-efficacy and entrepreneurial intention.

The interaction between ANXA2 and lncRNA Fendrr promotes cell apoptosis in caerulein-induced acute pancreatitis.

BACKGROUND: Annexin A2 (ANXA2) plays a crucial role in acute pancreatitis (AP). However, its potential mechanism remains unclear. METHODS: In the present study, we used caerulein-treated AR42J rat pancreatic acinar cells as cell model of AP to investigate the potential functions of ANXA2 and its predicted long noncoding RNA (lncRNA) FOXF1 adjacent noncoding developmental regulatory RNA (lncRNA Fendrr). Cell apoptosis was evaluated by flow cytometry using annexinV-fluorescein isothiocyanate/propidium iodide staining. The expressions of ANAX2 and lncRNA Fendrr were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, Western blot analysis was performed to determine the protein levels of ANXA2, Bcl-2, and Bax. The association between lncRNA Fendrr and ANXA2 was disclosed by RNA pull-down, RNA immunoprecipitation, and electrophoretic mobility shift assays. RESULTS: ANXA2 was elevated in caerulein-induced AP model and promoted apoptosis of AR42J cells. LncRNA Fendrr was also upregulated in AP cell model and directly bound ANXA2 protein. Further studies indicated that the interaction between ANXA2 and lncRNA Fendrr contributed to the apoptosis of AR42J cells in AP cell model. CONCLUSION: Our study demonstrated that ANXA2 promoted AP progression via interacting with lncRNA Fendrr in vitro, which will provide a novel insight into the therapeutic target for AP.

Modular bioinformatics analysis demonstrates that a Toll­like receptor signaling pathway is involved in the regulation of macrophage polarization.

In recent years, an increasing number of studies on the roles of macrophages in tumors, immune responses and metabolism have been published, in which macrophage polarization has been an extensively discussed topic. In the present study, differentially expressed genes in various types of macrophages were analyzed using the Gene Expression Omnibus database. Cluster analysis of differentially expressed genes was conducted, and a protein­protein interaction (PPI) network was constructed. Finally, modular analysis and functional enrichment analysis revealed that a Toll­like receptor (TLR) signaling pathway is involved in the regulation of macrophage polarization. Furthermore, the high­degree proteins in the PPI network that are involved in the molecular regulation of macrophage polarization are closely associated with proteins of the TLR signaling pathway. These results suggested that the TLR signaling pathways may be a principal direction of future research on the regulation of macrophage polarization.

Dual inhibition of Akt and c-Met as a second-line therapy following acquired resistance to sorafenib in hepatocellular carcinoma cells.

Sorafenib displays a limited efficacy for advanced hepatocellular carcinoma (HCC). Some patients with HCC initially respond to sorafenib, but eventually succumb to the disease, indicating that the acquired resistance to sorafenib reduces its beneficial effects. No alternative drugs are available after the failure of sorafenib therapy. Therefore, investigation of the mechanisms underlying the acquired resistance and development of second-line treatments for sorafenib-resistant HCC are urgently required. In this study, sorafenib-resistant HCC cells generated from sorafenib-sensitive human HCC cells were shown to overproduce hepatocyte growth factor (HGF) and overexpress c-Met kinase and its phosphorylated form, leading to the activation of Akt and ERK (extracellular signaling-regulated kinase) pathways. Use of specific c-Met inhibitors enhanced the effects of sorafenib by inhibiting the growth of sorafenib-resistant HCC cells. Akt inhibitors, a class of second-line therapeutic drugs under investigation for treating HCC in clinical trials, enhanced the effects of sorafenib, but also activated the c-Met pathway in sorafenib-resistant cells. Dual inhibition of Akt and c-Met by their respective inhibitors, MK2206 and capmatinib, additively or synergistically suppressed sorafenib-resistant HCC cells in vitro and sorafenib-resistant HCC xenografts in mice. The anticancer activities of MK2206 mainly rely on its ability to induce cell apoptosis and autophagic death, while capmatinib treatment leads to cell cycle arrest at phase G1. These results provide strong evidence for further investigation on the clinical utility of dual inhibition of Akt and c-Met, particularly MK2206 and capmatinib, as a second-line therapy for advanced HCC that has acquired resistance to sorafenib.

Bufalin reverses intrinsic and acquired drug resistance to cisplatin through the AKT signaling pathway in gastric cancer cells.

Cisplatin is the most common chemotherapeutic agent for gastric cancer (GC), however it activates AKT, which contributes to intrinsic and acquired resistance. Bufalin, a traditional Chinese medicine, shows significant anticancer activity by inhibiting the AKT pathway. It was therefore hypothesized that bufalin could counteract cisplatin resistance in GC cells. SGC7901, MKN­45 and BGC823 human GC cells were cultured under normoxic and hypoxic conditions. Effects of cisplatin and bufalin on GC cells were measured by a cell counting kit, apoptosis was analyzed by flow cytometry, and immunoblotting was used to detect proteins associated with the AKT signaling pathway. It was demonstrated that bufalin synergized with cisplatin to inhibit proliferation and promote apoptosis of GC cells by diminishing the activation of cisplatin-induced AKT under normoxic and hypoxic conditions. Bufalin also inhibits cisplatin-activated molecules downstream of AKT that affect proliferation and apoptosis, including glycogen synthase kinase, mammalian target of rapamycin, ribosomal protein S6 Kinase and eukaryotic translation initiation factor-4E-binding protein-1. To investigate acquired cisplatin resistance, a cisplatin­resistant cell line SGC7901­CR was used. It was demonstrated that bufalin reversed acquired cisplatin resistance and significantly induced apoptosis through the AKT pathway. These results imply that bufalin could extend the therapeutic effect of cisplatin on GC cells when administered in combination.

Down-regulation of AKT combined with radiation-induced autophagy and apoptosis roles in MCF-7 cells.

Autophagy is an evolutionarily conservation process whereby cytoplasm and cellular organelles are degraded in lysosomes for amino acid and energy recycling. Autophagy concurrent with radiotherapy has emerged as a novel approach in breast cancer treatment. Our studies conclude that autophagy and apoptosis can be induced by radiation and inhibition of autophagy can increase apoptosis. In addition, Akt is a molecule that down-regulates autophagy and apoptosis; blocking Akt can enhance autophagy and apoptosis induced by radiation in MCF-7 cells. Akt could become a new focus in breast cancer radiotherapy.

Bufalin Reverses Resistance to Sorafenib by Inhibiting Akt Activation in Hepatocellular Carcinoma: The Role of Endoplasmic Reticulum Stress.

Sorafenib is the standard first-line therapeutic treatment for patients with advanced hepatocellular carcinoma (HCC), but its use is hampered by the development of drug resistance. The activation of Akt by sorafenib is thought to be responsible for this resistance. Bufalin is the major active ingredient of the traditional Chinese medicine Chan su, which inhibits Akt activation; therefore, Chan su is currently used in the clinic to treat cancer. The present study aimed to investigate the ability of bufalin to reverse both inherent and acquired resistance to sorafenib. Bufalin synergized with sorafenib to inhibit tumor cell proliferation and induce apoptosis. This effect was at least partially due to the ability of bufalin to inhibit Akt activation by sorafenib. Moreover, the ability of bufalin to inactivate Akt depended on endoplasmic reticulum (ER) stress mediated by inositol-requiring enzyme 1 (IRE1). Silencing IRE1 with siRNA blocked the bufalin-induced Akt inactivation, but silencing eukaryotic initiation factor 2 (eIF2) or C/EBP-homologous protein (CHOP) did not have the same effect. Additionally, silencing Akt did not influence IRE1, CHOP or phosphorylated eIF2α expression. Two sorafenib-resistant HCC cell lines, which were established from human HCC HepG2 and Huh7 cells, were refractory to sorafenib-induced growth inhibition but were sensitive to bufalin. Thus, Bufalin reversed acquired resistance to sorafenib by downregulating phosphorylated Akt in an ER-stress-dependent manner via the IRE1 pathway. These findings warrant further studies to examine the utility of bufalin alone or in combination with sorafenib as a first- or second-line treatment after sorafenib failure for advanced HCC.

Bufalin promotes apoptosis of gastric cancer by down-regulation of miR-298 targeting bax.

Bufalin is used to treat many patients with solid malignant tumors clinically. Bufalin could induce gastric cancer cell apoptosis via BAX. microRNA (miRNA) plays important roles in gene regulation. However, miRNA involving in bufalin inducing apoptosis of gastric cancer cells remains to futher research. To study the regulatory role of miRNA in bufalin induced cancer cell apoptosis. Firstly, we verifed that bufalin could induce gastric cancer cell apoptosis by inducing BAX expression. miR-298 was predicted as a regulator of BAX and further study verified Bax was a target gene of miR-298 by luciferase reporter assay. miR-298 could down-regulate BAX on mRNA and protein level in gastric cancer cells. miR-298 promoted cell proliferation and inhibited apoptosis of gastric cancer cells. It was also found that bufalin inhibited cell proliferation and promoted cell apoptosis by down-regualtion of miR-298. In summary, bufalin-associated miR-298 may indirectly be involved in cell proliferation and apoptosis by targeting BAX, pointing to use as a potential molecular target in gastric cancer therapy.

Arsenic trioxide potentiates the anti-cancer activities of sorafenib against hepatocellular carcinoma by inhibiting Akt activation.

Sorafenib is the standard first-line systemic drug for advanced hepatocellular carcinoma (HCC), but it also induces the activation of Akt, which contributes to the mechanisms for the resistance to sorafenib. Arsenic trioxide (ATO) is a currently clinically used anticancer drug and displays its anticancer activities by inhibiting Akt activation. Therefore, we hypothesized that ATO may potentiate the anti-cancer activities of sorafenib against HCC. The results have demonstrated that ATO synergized with sorafenib to inhibit the proliferation and promote the apoptosis of HCC cells by diminishing the increased activation of Akt by sorafenib. ATO was shown to inhibit the expression or activation of Akt downstream factors, including glycogen synthase kinase (GSK)-3ß, mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase (S6K), and eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1), which regulate cell apoptosis and were upregulated or activated by sorafenib. Both sorafenib and ATO downregulated the expression of cyclin D1, resulting in HCC cells arrested at G0/G1 phase. ATO downregulated the expression of Bcl-2 and Bcl-xL and upregulated the expression of Bax, indicating that ATO could induce the apoptosis of HCC cells through the intrinsic pathways; but sorafenib showed little effects on these proteins of Bcl-2 family. ATO synergized with sorafenib to suppress the growth of HCC tumors established in mice by inhibiting the proliferation and inducing the apoptosis of HCC cells in situ. These results indicate that ATO may be a potential agent that given in combination with sorafenib acts synergistically for treating HCC.

2-Methoxyestradiol synergizes with sorafenib to suppress hepatocellular carcinoma by simultaneously dysregulating hypoxia-inducible factor-1 and -2.

Sorafenib is the approved systemic drug of choice for advanced hepatocellular carcinoma (HCC), but has demonstrated limited benefits because of drug resistance. 2-Methoxyestradiol (2ME2) has been shown to be a promising anticancer drug against various types of cancers and acts by dysregulating hypoxia-inducible factor (HIF)-1. Hypoxic cancer cells are extremely resistant to therapies since they elicit strong survival ability due to the cellular adaptive response to hypoxia, which is controlled by HIF-1 and HIF-2. The present study has demonstrated that sorafenib downregulated the expression of HIF-1α, making the hypoxic response switch from HIF-1α- to HIF-2α-dependent pathways, resulting in upregulation of HIF-2α, which contributes to the insensitivity of hypoxic HCC cells to sorafenib. HIF-2α played a dominant role in regulating VEGF, thus sorafenib in turn increased the expression of VEGF (a downstream molecule of both HIF-1 and HIF-2) and cyclin D1 (a downstream molecule of HIF-2), but reduced the expression of LDHA (a downstream molecule of HIF-1), in hypoxic HCC cells. 2ME2 significantly reduced the expression of both HIF-1α and HIF-2α, and their downstream molecules, VEGF, LDHA and cyclin D1, rendering hypoxic HCC cells to increased sensitivity to 2ME2. 2ME2 also inhibited the nuclear translocation of HIF-1α and HIF-2α proteins, but had no effect on their mRNA expression. 2M2 synergized with sorafenib to suppress the proliferation and induction of apoptosis of HCC cells in vitro and in vivo, and inhibited tumoral angiogenesis. These results indicate that 2ME2 given in combination with sorafenib acts synergistically for treating HCC.

Inhibition of Akt reverses the acquired resistance to sorafenib by switching protective autophagy to autophagic cell death in hepatocellular carcinoma.

Sorafenib is the standard first-line systemic drug for advanced hepatocellular carcinoma (HCC), but the acquired resistance to sorafenib results in limited benefits. Activation of Akt is thought to be responsible for mediating the acquired resistance to sorafenib. The present study aims to examine the underlying mechanism and seek potential strategies to reverse this resistance. Two sorafenib-resistant HCC cell lines, which had been established from human HCC HepG2 and Huh7 cells, were refractory to sorafenib-induced growth inhibition and apoptosis in vitro and in vivo. Sustained exposure to sorafenib activated Akt via the feedback loop of mTOR but independent of protein phosphatase 2A in HCC cells. Autophagy participated in the resistance to sorafenib as inhibition of autophagy reduced the sensitivity of sorafenib-resistant HCC cells to sorafenib, whereas activation of autophagy by rapamycin had the opposite effect. However, rapamycin did not show a synergistic effect with sorafenib to inhibit cell proliferation, while it also activated Akt via a feedback mechanism in sorafenib-resistant HCC cells. Inhibition of Akt reversed the acquired resistance to sorafenib by switching autophagy from a cytoprotective role to a death-promoting mechanism in the sorafenib-resistant HCC cells. Akt inhibition by GDC0068 synergized with sorafenib to suppress the growth of sorafenib-resistant HCC tumors that possessed the sorafenib-resistant feature in vivo. The results have provided evidence for clinical investigation of GDC0068, a novel ATP-competitive pan-Akt inhibitor, as the second-line treatment after the failure of sorafenib-medicated molecular targeted therapy for advanced HCC.

Upregulation of HIF-2α induced by sorafenib contributes to the resistance by activating the TGF-α/EGFR pathway in hepatocellular carcinoma cells.

Sorafenib, the first-line systemic drug for advanced hepatocellular carcinoma (HCC), has demonstrated limited benefits with very low response rates. Thus it is essential to investigate the underlying mechanisms for the resistance to sorafenib and seek potential strategy to enhance its efficacy. Hypoxic cells inside solid tumors are extremely resistant to therapies as their survival ability is increased due to the cellular adaptive response to hypoxia, which is controlled by hypoxia-inducible factor (HIF)-1 and HIF-2. Sorafenib inhibits HIF-1α synthesis, making the hypoxic response switch from HIF-1α- to HIF-2α-dependent pathways and providing a mechanism for more aggressive growth of tumors. The present study has demonstrated that upregulation of HIF-2α induced by sorafenib contributes to the resistance of hypoxic HCC cells by activating the transforming growth factor (TGF)-α/epidermal growth factor receptor (EGFR) pathway. Blocking the TGF-α/EGFR pathway by gefitinib, a specific EGFR inhibitor, reduced the activation of STAT (signal transducer and activator of transcription) 3, AKT and ERK (extracellular signal-regulated kinase), and synergized with sorafenib to inhibit proliferation and induce apoptosis of hypoxic HCC cells. Transfection of HIF-2α siRNA into HCC cells downregulated the expression of VEGF (vascular endothelial growth factor), cyclin D1, HIF-2α and TGF-α, and inhibited the activation of EGFR. HIF-2α siRNA inhibited the proliferation and promoted the apoptosis of HCC cells in vitro, and synergized with sorafenib to suppress the growth of HCC tumors in vivo. The results indicate that targeting HIF-2α-mediated activation of the TGF-α/EGFR pathway warrants further investigation as a potential strategy to enhance the efficacy of sorafenib for treating HCC.

Cardiovascular toxicity of different sizes amorphous silica nanoparticles in rats after intratracheal instillation.

The purpose of this work was to investigate the cardiovascular toxicity of different sizes and different dosages of silica nanoparticles in Wistar rats. The three silica nanoparticles (30, 60, and 90 nm) and one fine silica particles (600 nm) at three doses of 2, 5, and 10 (mg/Kg bw) were used in the present experiment. After intratracheal instillation for a total of 16 times, concentration of Si in hearts and serum was measured by inductively coupled plasma optical emission spectrometer. The hematology parameters were analyzed by an automated hematology analyzer, and the inflammatory reaction, oxidative stress, endothelial dysfunction, and the myocardial enzymes in serum were measured by kits. Our results showed intratracheal-instilled silica nanoparticles could pass through the alveolar-capillary barrier into systemic circulation. Concentration of Si in the heart and serum depended on the particles size and dosage. The levels of reactive oxygen species (ROS) at 5, 10 mg/Kg bw of the three silica nanoparticles were higher than the fine silica particles. Blood levels of inflammation-related high-sensitivity C-reactive protein and cytokines such as interleukin-1beta (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor-alpha were increased after exposure to three silica nanoparticles at 10 mg/Kg bw. Moreover, the levels of IL-1ß and IL-6 at 10 mg/Kg bw of silica nanoparticles (30 nm) were higher than the fine silica particles. Significant decrease in superoxide dismutase, glutathione peroxidase and significant increase in malondialdehyde were observed at 10 mg/Kg bw of the three silica nanoparticles. A significant decrease in nitric oxide (NO) production was induced which coincided with the reduction of nitric oxide synthase (NOS) activity and the excessive generation of ROS in rats. The levels of intercellular adhesion molecule-l and vascular cell adhesion molecule-l elevated significantly after exposure to three silica nanoparticles at 10 mg/Kg bw, which are considered as early steps of endothelial dysfunction. We conclude that cardiovascular toxicity of silica nanoparticles could be related to the particles size and dosage. Oxidative stress could be involved in inflammatory reaction and endothelial dysfunction, all of which could aggravate cardiovascular toxicology. In addition, endothelial NO/NOS system disorder caused by nanoparticles could be one of the mechanisms for endothelial dysfunction.