Primordial follicle pool is the foundation of female reproductive life and abnormal primordial follicle activation may lead to severe diseases such as premature ovarian failure and premature ovarian insufficiency. Golgi reassembly stacking protein 2 (GORASP2) plays an important role in autophagy by regulating autophagy maturation through glycosylation modification. In the current study we found that GORASP2 is a key factor in mammalian primordial follicle activation through autophagy lysosome pathway. Knocking down of Gorasp2 in the ovaries of newborn mice led to decreased number of activated primary follicles, and the level of FSH (Follicle-stimulating Hormone) in the primary follicles was increased. Comparing with negative control ovaries, transcription profiling showed differentially expressed genes were mainly enriched in the autophagic lysosome, HIF-1 signaling pathway and PI3K-AKT signaling pathway. We found that the ratio of autophagy marker protein LC3-II/LC3-I increased and the level of SQSTM1 protein decreased by Western blot, indicating an elevated autophagy level in GORASP2-knockdown ovaries. Further examination demonstrated that the small G protein Rap1, a member of the Ras superfamily was activated after GORASP2 inhibition and the phosphorylation of mTOR was inhibited by disrupting the mTOR-Raptor interaction, thus initiating autophagy in primordial follicles. In addition, levels of ROS and ATP were increased and citrate lyase was decreased, suggesting a putative disrupted mitochondrial function. Finally, AKT signaling pathways were blocked and may also affect the developmental potential of these affected primordial follicles. In summary, our study emphasized the Golgi stacking protein GORASP2 as an important regulator in primordial follicle activation by participating in the initiation of autophagy, providing an experimental basis for the involvement of Golgi related components in the activation process of primordial follicles through autophagy pathway. This study also shed light upon the deeper understanding of primordial follicle activation related diseases and may contribute a new angle for their future treatment.

BACKGROUND:Numerous pathogenic variants causing human oocyte maturation arrest have been reported on the primate-specific TUBB8 gene. The main etiology is the dramatic reduction of tubulin α/β dimer, but still large numbers of variants remain unexplained. METHODS:Using microinjection mRNA and genome engineering to reintroduce the conserved pathogenic missense variants into oocytes or in generating TUBB8 variant knock-in mouse models, we investigated that the human deleterious variants alter microtubule nucleation and spindle assembly during meiosis. Live-cell imaging and immunofluorescence were utilised to track the dynamic expression of microtubule plus end-tracking proteins in vivo and analysed microtubule nucleation or spindle assembly in vitro, respectively. Immunoprecipitation-mass spectrometry and ultramicro-quantitative proteomics were performed to identify the differential abundance proteins and affected interactome of TUBB8 protein. RESULTS:First, we observed a significant depletion of the EB1 signal upon microinjection of mutated TUBB8 mRNA (including R262Q, M300I, and D417N missense variants), indicating disruption of microtubule nucleation caused by these introduced TUBB8 missense variants. Mechanically, we demonstrated that the in vivo TUBB8-D417N missense variant diminished the affinity of EB1 and microtubules. It also harmed the interaction between microtubules and CKAP5/TACC3, which are crucial for initiating microtubule nucleation. Attenuated Ran-GTP pathway was also found in TUBB8-D417N oocytes, leading to disrupted spindle assembly. Stable microtubule was largely abolished on the spindle of TUBB8-D417N oocytes, reflected by reduced tubulin acetylation and accumulated HDAC6. More importantly, selective inhibition of HDAC6 by culturing TUBB8-D417N oocytes with Tubacin or Tubastatin A showed morphologically normal spindle and drastically recovered polar-body extrusion rate. These rescue results shed light on the strategy to treat meiotic defects in a certain group of TUBB8 mutated patients. CONCLUSION:Our study provides a comprehensive mechanism elucidating how TUBB8 missense variants cause oocyte maturation arrest and offers new therapeutic avenues for treating female infertility in the clinic.

Deoxynivalenol (DON) is one of the most common food contaminants, widely present in grain products. Studies using murine and porcine models show deoxynivalenol exposure impairs oocyte maturation and mitochondrial function; however, the exact mechanisms remain unclear. Here, we demonstrate that DON exposure markedly altered the microtubule nucleation-associated protein expression in oocytes. Pharmacological inhibition of HDAC6 with Tubacin rescued maturation arrest and restored expression of key microtubule regulators KIF11 and TPX2, which are key factors for microtubule nucleation and spindle stabilization. More importantly, we developed an in vivo TUBB8 oocyte-specific knock-in model. In our expressing human β-tubulin isotype model, Tubacin reconstructed normal spindles and drastically restored polar body extrusion in DON-exposed oocytes. Mechanistically, DON represses mRNA translation and disrupts ribosomal function. In our investigation, DON interfered with fertilized zygote cleavage by disrupting microtubule and microfilament networks, and Tubacin enhanced microtubule acetylation, stabilizing the network and rescuing developmental arrest. Taken together, this study establishes Tubacin's therapeutic potential against DON-induced reproductive toxicity, and validated the novel TUBB8 oocyte-specific knock-in mouse model as a rapid evaluation of exposure and potential treatment of environmental pollutants to female reproductive health.

While previous studies have indicated the involvement of Isthmin 1 (ISM1), a secreted protein, in cancer development, the precise mechanisms have remained elusive. In this study, we unveiled that ISM1 is significantly overexpressed in both the blood and tissue samples of colorectal cancer (CRC) patients, correlating with their poor prognosis. Functional experiments demonstrated that enforced ISM1 expression significantly enhances CRC proliferation, migration, invasion and tumor growth. Notably, our investigation reveals an interaction of ISM1 with epidermal growth factor receptor (EGFR), a member of the receptor tyrosine kinase (RTK) family of CRC cells. The binding of ISM1 triggered EGFR activation and initiate downstream signaling pathways. Meanwhile, intracellular ISM1 interacted with Y-box binding protein 1 (YBX1), enhancing its transcriptional regulation on EGFR. Furthermore, our research uncovered the regulation of ISM1 expression by the hypoxia-inducible transcription factor HIF-1α in CRC cells. Mechanistically, we identified HIF-1α as a direct regulator of ISM1, binding to a hypoxia response element on its promoter. This novel mechanism illuminated potential therapeutic targets, offering insights into restraining HIF-1α/ISM1/EGFR-driven CRC progression and metastasis.

Mesenchymal stem cell (MSC)-based cardiac patches are envisioned to be a promising treatment option for patients with myocardial infarction. However, their therapeutic efficacy and duration are hampered due to their limited retention on the epicardium. We engineered a scaffold-free MSC sheet with an inherent ability to migrate into the infarcted myocardium, a strategy enabled by actively establishing a sustained intracellular hypoxic environment through the endocytosis of our FDA-approved ferumoxytol. This iron oxide nanoparticle stabilized hypoxia-induced factor-1α, triggering upregulation of the CXC chemokine receptor and subsequent MSC chemotaxis. Thus, MSCs integrated into 2/3 depth of the left ventricular anterior wall in a rat model of acute myocardial infarction and persisted for at least 28 days. This led to spatiotemporal delivery of paracrine factors by MSCs, enhancing cardiac regeneration and function. Ferumoxytol also facilitated the noninvasive MRI tracking of implanted MSCs. Our approach introduces a strategy for mobilizing MSC migration, holding promise for rapid clinical translation in myocardial infarction treatment.

Catalytic gold nanomaterials typically exhibit antibacterial properties, albeit significantly weaker than ionic gold in chrysotherapy. The inherent stability of gold nanoparticles prevents the release of gold ions, limiting their ability to achieve efficient antibacterial therapy. To address this limitation, we propose a novel sustained ionic gold release strategy through the construction of a mixed-valence gold-porphyrin coordination network (Au-Por). By adjusting the ratio of Au to porphyrin molecule, an ultrathin two-dimensional Au-Por nanosheet was successfully synthesized, which contains 85.9 % of Au (III). In addition, the remaining gold existed in the form of uniformly distributed ultrasmall nanoclusters on the Au-Por nanosheet. Notably, the Au-Por nanosheet exhibited a sustained release of gold ions. Thus, a multimodal antibacterial therapy was achieved by integrating the direct bactericidal action of ionic gold and lethal reactive oxygen species (ROS) generated through the peroxidase (POD)-like activity of gold nanoclusters and photodynamic therapy (PDT) using porphyrins. The innovative AuPor exerted broad-spectrum bactericidal activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria mediated by bacterial membrane disruption and DNA damage. Moreover, in vivo studies demonstrated the synergistic effect of Au-Por on combating skin wound infections and facilitating wound healing. Comprehensive safety evaluations proved that Au-Por exhibited no hematotoxicity or hepatorenal toxicity, and it also displayed rapid renal clearance after treatment, indicating favorable biocompatibility. The repurposing of chrysotherapy has revolutionized the antibacterial strategy of nanoscale gold, resulting in a dramatic boost in antibacterial activity and valuable insights for designing highly efficient nanoscale antibacterial agents.

移动数字化背景下病理学实验自主学习模式的应用,将病理学实验由传统的"以教为主"转变为"以学为主",激发了学生的学习兴趣,提高了学习资源的利用率,优化了病理学实验的教学效果.

Background: Our previous studies have shown that the E3 ubiquitin ligase of HMG-CoA reductase degradation 1 (HRD1) functions as a tumor suppressor, as overexpression of HRD1 suppressed breast cancer proliferation and invasion. However, its role in breast cancer cell glucose metabolism was unclear. Here, our aim was to uncover the role and molecular mechanisms of HRD1 in regulating aerobic glycolysis in breast cancer. Methods: The effect of HRD1 on robic glycolysis in breast cancer cells were assessed. Then the proliferation, colony formation ability, invasion and migration of breast cancer cells were evaluated. The relationship between HRD1 and PFKP was validated by Mass spectrometry analysis, immunofluorescence and co-immunoprecipitation. The level of PFKP ubiquitination was measured using ubiquitylation assay. Furthermore, the tumor growth and metastasis in mice xenografts were observed. Results: We found that upregulation of HRD1 clearly decreased aerobic glycolysis, and subsequently inhibited breast cancer proliferation and invasion. Mass spectrometry analysis results revealed a large HRD1 interactome, which included PFKP (platelet isoform of phosphofructokinase), a critical enzyme involved in the Warburg Effect in breast cancer. Mechanistically, HRD1 interacted and colocalized with PFKP in the cytoplasm, targeted PFKP for ubiquitination and degradation, and ultimately reduced PFKP expression and activity in breast cancer cells. HRD1 inhibited breast cancer growth and metastasis in vivo through a PFKP-dependent way. Conclusions: Our findings reveal a new regulatory role of HRD1 in Warburg effect and provide a key contributor in breast cancer metabolism.

Aberrant microRNA (miRNA) expressions contribute to the development and progression of various diseases, including Crohn's disease (CD). However, the accurate mechanisms of miRNAs in CD are definitely unclear. We employed colonic tissue samples from normal volunteers and CD patients, an acute mice colitis model induced by 2,4,6-trinitro-benzene-sulfonic acid (TNBS), and a cellular oxidative stress model induced by H2O2 in HT-29 cells to determine the effects of oxidative stress on expressions of miR-122, selenium-binding protein 1 (SELENBP1, SBP1), p65 nuclear factor κB (p65NF-κB) signaling, and DNA methylation. We found that SBP1 was mainly located on epithelial cells and was significantly increased in patients with active CD. SBP1 was the target gene of miR-122. miR-122 expression was downregulated while SBP1 expression was upregulated under TNBS-induced colitis or oxidative stress. Pre-miR-122 or siRNA SBP1 (si-SBP1) treatment ameliorated acute TNBS-induced colitis and H2O2-induced oxidative stress. Cotreatment of pre-miR-122 and si-SBP1 enhanced these effects. Besides, pre-miR-122 and si-SBP1 obviously activated the p65NF-κB signaling by phosphorylation of IκBα. Bisulfite sequencing of the CpG islands in the promoter region of miR-122 showed that CpG methylation was significantly increased under oxidative stress. Treating cells with 5'-AZA which was well known as a DNA-demethylating agent significantly increased miR-122 expression. Our results suggest that oxidative stress-induced DNA methylation of miR-122 aggravates colitis targeting SELENBP1 partially by p65NF-κB signaling and may promote the progression of CD.

Objective To evaluate analytical perfortnance and clinical application value of a one-step HBV DNA quantitative detecting system.Methods Analytical performance of the one-step HBV DNA quantitative detecting reagents included precision,residual contamination,accuracy,functional sensitivity and analytical measurement range were verified by collecting high concentration samples and external quality control samples from Jiangsu provincial clinical test center.Results The within-run coefficient of variation (CV) of both low and high concentration samples were below 5％,meanwhile the intra-assay CV was below 3/5 TEa and inter-assay CV was below 4/5 TEa.There was no residual contamination and the analytic accuracy met the requirement of external quality assessment (EQA).Functional sensitivity was able to attain 100 IU/ml,while the day to day CV was below 20％.It exhibited a benign Iinear relation from 7.58 × 101 to 7.58 × 108 [U/ml.Conclusions The analytic performance of a new testing system must be evaluated particularly before detecting samples of patients by quantitative tests.This study proves that the one-step HBV DNA quantitative detecting reagents can meet requirement of hepatitis B screening and clinical therapy monitoring,which is economic and simple for clinical routine tests.

AIM:To observe the levels of monocyte-platelet aggregates (MPA) and markers of activated monocytes in patients with unstable angina pectoris (UAP) accepting Ginkgo biloba tablet treatments,and to explore its mechanisms for cardiovascular disease treatments.METHODS:The levels of MPA,CD11b,and MCP-1 were measured in 92 unstable angina pectoris (UAP) and 42 stable angina pectoris (SAP).The UAP patients were randomly assigned into routine treatment group (control group) and combined tablet treatment group (Ginkgo biloba group).The efficacy was assessed,and the levels of MPA,CD11b,and MCP-1 were measured after 28 days of treatment,respectively.RESULTS:The levels of MPA,CD11b,and MCP-1 in UAP group were higher than those in SAP group (P＜0.001).The levels of MPA and CD11b were positively correlated with MCP-1 level (P ＜ 0.01).The total rate of effective Ginkgo biloba tablet treatment was higher than that of non-Ginkgo biloba tablet treatment (P ＜ 0.05).After 28 days of treatments,the levels of MPA,CD11b,and MCP-1 in Ginkgo biloba group were significantly lower than those in control group (P ＜ 0.001).In total effective treatment group,the levels of MPA,CD11b,and MCP-1 were significantly lower after treatment than those before treatment (P ＜ 0.001),and the decreased rates of these markers after treatment were also much higher (P ＜ 0.01).CONCLUSION:There is an obvious efficacy of Ginkgo biloba tablet on unstable angina pectoris by down-regulating the levels of MPA,CD11b and MCP-1.

Cyclooxygenase-2 (COX-2) has been implicated in cell invasion in non-small-cell lung cancer (NSCLC). However, the mechanism is unclear. The present study investigated the effect of COX-2 on β1-integrin expression and cell invasion in NSCLC. COX-2 and β1-integrin were co-expressed in NSCLC tissues. COX-2 overexpression or Prostaglandin E2 (PGE2) treatment increased β1-integrin expression in NSCLC cell lines. β1-integrin silencing suppressed COX-2-mediated tumour growth and cancer cell invasion in vivo and in vitro. Prostaglandin E Receptor EP1 transfection or treatment with EP1 agonist mimicked the effect of PGE2 treatment. EP1 siRNA blocked PGE2-mediated β1-integrin expression. EP1 agonist treatment promoted Erk1/2, p38 phosphorylation and E2F-1 expression. MEK1/2 and p38 inhibitors suppressed EP1-mediated β1-integrin expression. E2F-1 silencing suppressed EP1-mediated FoxC2 and β1-integrin upregulation. ChIP and Luciferase Reporter assays identified that EP1 agonist treatment induced E2F-1 binding to FoxC2 promotor directly and improved FoxC2 transcription. FoxC2 siRNA suppressed β1-integrin expression and EP1-mediated cell invasion. Immunohistochemistry showed E2F-1, FoxC2, and EP1R were all highly expressed in the NSCLC cases. This study suggested that COX-2 upregulates β1-integrin expression and cell invasion in NSCLC by activating the MAPK/E2F-1 signalling pathway. Targeting the COX-2/EP1/PKC/MAPK/E2F-1/FoxC2/β1-integrin pathway might represent a new therapeutic strategy for the prevention and treatment of this cancer.

目的:探讨炎症小体NLRP3在鼻咽癌组织和正常鼻咽黏膜组织中的表达水平变化及其与患者临床预后的关系.方法:采用实时定量PCR和免疫组化检测40例鼻咽癌组织和12例正常鼻咽黏膜组织中NLRP3的表达水平.结果:①NLRP3在鼻咽癌组织中表达显著高于正常鼻咽黏膜组织(P＜0.05);②在鼻咽癌患者中,NLRP3的表达水平与肿瘤的淋巴结转移以及患者的临床预后有关(P＜0.05),NLRP3高表达患者较低表达患者具有更好的局部无复发生存率和无瘤生存率,但与年龄和组织病理类型无明显相关关系(P＞0.05).结论:NLRP3具有提示鼻咽癌肿瘤转移及判断患者预后的价值.

Prostaglandin E2 (PGE2) is involved in cholangiocarcinoma cell proliferation, migration and invasion through E prostanoid receptors, including EP1, EP2 and EP4. However, the functions and the mechanisms of those splice variants of EP3 receptors in promoting liver cancer cell growth and invasion remain to be elucidated. In our previous studies, four isoforms of EP3 receptors, EP3-4, EP3-5, EP3-6 and EP3-7 receptors, were detected in CCLP1 and HuCCT1 cells. However, the functions of these receptors in these cells have yet to be determined. It was reported that β-catenin is closely correlated with malignancy, including cholangiocarcinoma. The present study was designed to examine the effects of 4-7 isoforms of EP3 in promoting cholangiocarcinoma progression and the mechanisms by which PGE2 increases β-catenin protein via EP3 receptors. The results showed that PGE2 promotes cholangiocarcinoma progression via the upregulation of β-catenin protein, and the EP3-4 receptor pathway is mainly responsible for this regulation. These findings reveal that PGE2 upregulated the cholangiocarcinoma cell β-catenin protein through the EP3-4R/Src/EGFR/PI3K/AKT/GSK-3β pathway. The present study identified the functions of EP3 and the mechanisms by which PGE2 regulates β-catenin expression and promoted cholangiocarcinoma cell growth and invasion.

目的:探讨在肝细胞肝癌Huh-7细胞中前列腺素E2EP3各受体亚型对肿瘤细胞生长与侵袭的作用.方法:对常规培养的人肝细胞肝癌Huh-7细胞,瞬时转染EP3受体的4个亚型EP3-4R、EP3-5R、EP3-6R、EP3-7R,应用RT-PCR实验检测转染细胞EP3受体各亚型的mRNA表达水平;应用Western blot实验检测相关蛋白水平.对转染后的Huh-7细胞,分别给予不同浓度的EP3受体激动剂sulprostone作用24 h,用WST-8细胞增殖测定试剂检测细胞的增殖情况;应用划痕实验检测细胞的侵袭性;应用Western blot实验检测细胞内ERK蛋白磷酸化水平的变化.结果:RT-PCR及Western blot实验结果显示Huh-7细胞EP3受体表达水平明显增高.WST-8实验显示,经10 μmol/L sulprostone处理24 h后,过表达EP3-4R、EP3-5R和EP3-7R亚型的细胞增殖率分别达到126.7％、124.0％、123.8％.划痕实验结果显示,过表达细胞的侵袭性分别增加到135.8％、123.5％、128.7％.Westem blot显示,EP3-4R、EP3-5R和EP3-7R转染细胞内ERK磷酸化水平分别上调了54.8％、33.4％、44.3％.而过表达EP3-6受体亚型细胞的增殖率、侵袭率和胞内ERK磷酸化水平改变不明显.结论:Huh-7肝癌细胞中,EP3-4R、EP3-5R及EP3-7R这3种受体亚型对细胞的生长及侵袭有显著促进作用,而EP3-6R亚型则无明显的促进作用.EP3受体促进肝癌细胞生长和侵袭的作用与ERK激活的现象一致.

Objective To investigate the ef ect of prostaglandin E2 (PGE2) on the receptor of stromal cel -derived factor-1 (chemokine receptor 4, CXCR4)in Endometrial Cancer Ishikawa cel s. Methods Ishikawa cel s were treated with PGE2, EP1 receptor agonist, EP1 receptor antagonist, protein kinase C (PKC)inhibitor and Ca2+chelating agent, Real-time PCR,Western Blot were employed to detect the level of CXCR4 mRNA and CXCR4 protein in Ishikawa cel s. Results The mRNA level of CXCR4 increased 75.7% ( <0.05),while the level of CXCR4 protein increased 70.93% ( <0.01) after treated with 5μmol/L PGE2. When treated with 5μmol/L EP1 receptor agonist 17-PT-PGE2, the level of CXCR4 protein increased 84.82% ( <0.01).The protein level decreased%54.62%( <0.05) after treated with 10μmol/L EP1 receptor antagonist sc-51322 compared with the cel s treated with PGE2.When treated with 5μmol/L PKC inhibitor BIS-1, 10μmol/L Ca2+chelating agent BAPTA-AM, the protein levels of CXCR4 were decreased 50.17%( <0.05),56.33%( <0.05)compared with the cel s treated with 17-PT-PGE2. Conclusion PGE2 might up-regulate the expression level of CXCR4 through EP1 receptor which could be partly related to the Ca2+/PKC signaling pathway in Endometrial Cancer Ishikawa cel s.

目的 探讨2型糖尿病肾病患者血浆中HIF1和COX2水平的变化及其在2型糖尿病肾病中的作用机制.方法 收入45例2型糖尿病患者及37例年龄/性别匹配的健康志愿者,检测其血浆中HIF1和COX2的表达水平.另外,建立2型糖尿病肾病的大鼠模型,其中正常组和对照组各15只,分别检测2型糖尿病肾病大鼠血液和肾脏中HIF1和COX2的表达水平.结果 糖尿病患者血清水平HIF1 (75.58±7.84)ng/mL及COX2水平(53.59±8.60)pg/mL均显著高于对照组[H1F1 (1.59±0.27)ng/mL,COX2(1.71±0.61)pg/mL] (P＜0.05);HIF1和COX2之间存在正相关,差异有统计学意义(r=0.975,P＜0.05).与正常对照组比较,糖尿病大鼠血、尿HIF1和COX2水平均增高;Western blotting结果显示,糖尿病大鼠肾病组织中HIF1和COX2表达量明显上调.结论 2型糖尿病患者和糖尿病肾病的大鼠模型血清中HIF1和COX2表达量都明显上调,表明二者在糖尿病肾病的发生发展中都起着重要作用.

目的:探讨前列腺素E2(PGE2)上调人卵巢癌SKOV3细胞CXC趋化因子受体4(CXC chemokine receptor 4,CXCR4)的表达从而促进细胞侵袭能力的机制.方法:用PGE2、EP1受体激动剂或抑制剂、CXCR4抑制剂、蛋白激酶C(PKC)抑制剂和钙离子螯合剂处理SKOV3细胞,通过real-time PCR、Western blot、Transwell实验检测CXCR4 mRNA水平、蛋白水平以及细胞的侵袭能力.结果:5 μmol/L PGE2处理SKOV3细胞后,CXCR4 mRNA及蛋白水平与对照组相比分别上升了60.33％、122.88％(P均＜0.01),细胞的侵袭能力较对照组增强了112.24％(P＜0.01);而经10 μmol/L CXCR4抑制剂AMD3465处理后,细胞的侵袭水平较PGE2处理组下降了54.00％(P＜ 0.05);5μmol/L EP1受体激动剂17-PT-PGE2处理SKOV3细胞后,CXCR4 mRNA及蛋白水平与对照组相比分别上升了47.90％(P＜ 0.01)、85.56％(P＜ 0.05),细胞的侵袭能力较对照组增强了108.79％(P＜ 0.01);而10 μmol/L EP1受体抑制剂sc-51322处理后,CXCR4蛋白表达水平较PGE2处理组下降了54.86％(P＜ 0.05),细胞的侵袭水平较PGE2处理组下降了65.37％(P＜ 0.05);5μmol/L PKC抑制剂BIS-1、10 μmol/L钙离子螯合剂BAPTA-AM处理后,CXCR4蛋白表达水平较17-PT-PGE2处理组分别下降了57.38％、56.14％ (P均＜0.05),细胞的侵袭水平较17-PT-PGE2处理组下降了52.63％、55.26％(P＜均0.05).结论:PGE2可通过激活EP1受体经Gαq/Ca2+/PKC信号转导通路上调卵巢癌SKOV3细胞CXCR4的表达,从而增强肿瘤细胞的侵袭能力.

Hepatocellular carcinoma (HCC) represents a major health problem worldwide. Prostaglandin E-2 (PGE(2)), the predominant product of cyclooxygenase-2, has been implicated in hepatocarcinogenesis. However, the underlying molecular mechanisms remain to be further elucidated. c-myc, a cellular proto-oncogene, is activated or overexpressed in many types of human cancer, including HCC. The present study was designed to investigate the internal relationship and molecular mechanisms between PGE(2) and c-Myc in HCC, and to define its role in HCC cell growth and invasion. Our results showed that PGE(2) significantly upregulated c-Myc expression at both the mRNA and protein levels, and knockdown of c-Myc blocked PGE(2)-induced HCC cell growth and invasive ability in human HCC Huh-7 cells. The effect of PGE(2) on c-Myc expression was mainly through the EP4 receptor, and EP4 receptor-mediated c-Myc protein upregulation largely depended on de novo biosynthesis of c-Myc mRNA and its protein. EP4 receptor signaling activated G(s)/AC and increased the intracellular cAMP level in Huh-7 cells. The adenylate cyclase (AC) activator forskolin mimicked the effects of the EP4 receptor agonist on c-Myc expression, while the AC inhibitor SQ22536 reduced EP4 receptor-mediated c-Myc upregulation. These data confirm the involvement of the G(s)/AC/cAMP pathway in EP4 receptor-mediated c-Myc upregulation. Moreover, the phosphorylation levels of CREB protein were markedly elevated by EP4 receptor signaling, and by using specific inhibitor and siRNA interference, we demonstrated that PKA/CREB was also involved in the EP4 receptor-mediated c-Myc upregulation. In summary, the present study revealed that PGE(2) significantly upregulates c-Myc expression at both mRNA and protein levels through the EP4R/G(s)/AC/cAMP/PKA/CREB signaling pathway, thus promoting cell growth and invasion in HCC cells. Targeting of the PGE(2)EP4R/c-Myc pathway may be a new therapeutic strategy to prevent and cure human HCC.