Early and Delayed Meniscal Shrinkage After Fresh-Frozen Lateral Meniscal Allograft Transplantation: Magnetic Resonance Imaging Study With a Midterm Follow-up.

PURPOSE: To evaluate whether fresh-frozen meniscal allograft shrinkage occurs only during the first year of the early remodeling period or progresses over the delayed period of midterm years and to determine whether these changes were associated with certain clinical and radiologic outcomes. METHODS: We retrospectively reviewed meniscal allograft transplantations (MATs) performed by 1 senior surgeon (S-I.B.) using fresh-frozen allograft from 2008 to 2013. The inclusion criteria were the patients who had midterm follow-up magnetic resonance imaging (MRI) scans between 3 and 6 years after isolated lateral MATs. We excluded the graft tears found on the 1-year or midterm MRI scans. MATs were indicated for the treatment persistent compartmental pain in young to middle-aged, physically active patients who had well-aligned nonarthritic joint without ligament insufficiency. The meniscal width of the transplants at the midbody and posterior horn was measured on day 2 (as a reference), at 1 year (after early remodeling period), and after 3 to 6 years (delayed period) postoperatively. Joint space width changes during each interval were measured on 45° flexion posteroanterior views. The Lysholm score and Tegner activity scale were used to evaluate clinical outcomes. RESULTS: Eighty-four isolated lateral MATs with the midterm MRI scans were identified. Of these, 17 graft tears were found; therefore, we analyzed 67 patients (32 male and 35 female patients) with a mean age of 30.9 years (range, 15-52 years). The mean relative meniscal width at the midbody decreased to 93.7% (95% confidence interval [CI], 91.8%-95.6%; P < .001) at 1 year postoperatively and to 88.0% (95% CI, 85.6%-90.3%; P < .001) at the midterm follow-up of 4.0 ± 1.0 years. The posterior horn shrank less than the midbody during the same period (96.0%; 95% CI, 94.8%-97.1%) at 1 year (P < .001) and 92.5% (95% CI, 91.0%-94.1%) at the last follow-up (P < .001). Although there was no severe shrinkage (>50% of the initial size), the incidence of moderate (25%-50%) changes at the midbody increased from 1 (1.5%) at 1 year to 5 (7.5%) at the last follow-up, respectively. We could not find any significant positive correlations between the relative meniscal width and patient-reported outcomes or joint space width changes after 1 year or at the last follow-up. CONCLUSIONS: Shrinkage of fresh-frozen meniscal transplants occurred during both the early remodeling and delayed midterm periods. Although the changes were greater in the midbody than in the posterior horn, the overall changes were less than those of the previous studies using cryopreserved grafts. We could not find that the meniscal shrinkage over the midterm period were significantly associated with inferior outcomes in this series. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Cervical sagittal alignment in patients with adolescent idiopathic scoliosis: is it corrected by surgery?

OBJECTIVE Cervical sagittal alignment (CSA) is related to function and quality of life, but it has not been frequently studied in patients with adolescent idiopathic scoliosis. This study aimed to reveal the change in CSA following corrective surgery, compare the cervical sagittal parameters according to curve types, and assess related factors for postoperative aggravation of CSA. METHODS The authors studied 318 consecutive patients with adolescent idiopathic scoliosis who underwent corrective surgery at a single center. Occiput-C2 and C2-7 lordosis, C2-7 sagittal vertical axis (SVA), T-1 slope, thoracic kyphosis, and lumbar sagittal profiles were measured preoperatively and postoperatively. Scoliosis Research Society Outcomes Questionnaire (SRS-22) scores were used as clinical outcomes. Each radiological parameter was compared preoperatively and postoperatively according to curve types (double major, single thoracic, and double thoracic curves). Patients were grouped based on preoperative CSA: the lordotic group (group L) and the kyphotic group (group K). Each radiological parameter was compared between the groups. Related factors for postoperative aggravation of CSA were assessed using multivariate logistic analysis. RESULTS Of the total number of patients studied, 67.0% (213 of 318) and 54.4% (173 of 318) showed cervical kyphotic alignment preoperatively and postoperatively, respectively. C2-7 lordosis increased (from -5.8° to -1.1°; p < 0.001) and C2-7 SVA decreased (from 24.2 to 20.0 mm; p < 0.001) postoperatively regardless of curve types. Although group K showed improvement in C2-7 lordosis (from -12.7° to -4.8°; p < 0.001), group L showed no difference (from 9.0° to 6.9°; p = 0.115) postoperatively. Clinical outcomes were not related to the degree of cervical kyphosis in this cohort. C2-7 lordosis (p < 0.001) and pelvic tilt (p = 0.019) were related to postoperative aggravation of CSA. CONCLUSIONS Regardless of the trend of improvement in CSA, many patients (54.4%) still showed cervical kyphotic alignment postoperatively. C2-7 lordosis and C2-7 SVA improved postoperatively in all curve types. However, postoperative changes in C2-7 lordosis showed different results based on preoperative CSA, which could be related to T-1 slope and thoracic kyphosis. However, clinical outcomes showed no difference based on CSA in this study cohort. Greater C2-7 lordosis and proximal thoracic curve preoperatively were risk factors for postoperative aggravation of CSA (p < 0.001 and p = 0.019, respectively).

A Retrospective Mid- and Long-term Follow-up Study on the Changes in Hematologic Parameters in the Highly Exposed Residents of the Hebei Spirit Oil Spill in Taean, South Korea.

OBJECTIVES: This study aimed to analyze changes in hematologic parameters in the residents of the areas highly contaminated by the Hebei Spirit Oil Spill in 2007 and those who participated in the clean-up activities. METHODS: According to demographic characteristics, health status and behavior, and level of exposure to oil, we compared the hematologic results in 2009 and 2012 among 701 residents. The hematologic parameters were composed of white blood cell (WBC) count, and levels of hemoglobin, hematocrit (Hct), aspartate aminotransferase (AST), alanine aminotransferase (ALT), glucose, glycosylated hemoglobin (HbA1c), blood urea nitrogen (BUN), creatinine (Cr), total cholesterol (T-chol), high-density lipoprotein (HDL), and triglyceride (TG). RESULTS: Paired t-test revealed that the WBC count and levels of Hct, AST, ALT, glucose, and HbA1c significantly increased, whereas the BUN, Cr, HDL, and TG levels significantly decreased. Multiple linear regression modelling showed a relationship between the level of exposure to oil and temporal changes in Hct, glucose, HbA1c, and BUN levels. CONCLUSION: Our results suggest a relationship between level of exposure to oil and changes in hematologic parameters over 3 years. Further studies should be conducted to determine the impact of oil spill on health such as the occurrence of diseases.

Schisandra chinensis and Morus alba Synergistically Inhibit In Vivo Thrombus Formation and Platelet Aggregation by Impairing the Glycoprotein VI Pathway.

Morus alba L. (MAL) extract has been used in traditional medicine for its cardioprotective and antiplatelet effects, while another herbal remedy, Schisandra chinensis (SCC), has been reported to have anti-inflammatory and antioxidant properties. We evaluated underlying cellular changes exerted by extracts of these plants on platelet function and effects of SCC + MAL on in vivo thrombus formation using AV shunt and tail thrombosis-length models in rats. In vitro platelet aggregation, granule secretion, and [Ca2+] i release assays were carried out. The activation of integrin αIIbß3 and phosphorylation of downstream signaling molecules, including MAPK and Akt, were investigated using cytometry and immunoblotting, respectively. Scanning electron microscopy (SEM) was used to evaluate changes in platelet shape and HPLC analysis was carried out to identify the marker compounds in SCC + MAL mixture. In vivo thrombus weight and average length of tail thrombosis were significantly decreased by SCC + MAL. In vitro platelet aggregation, granule secretion, [Ca2+] i release, and integrin αIIbß3 activation were notably inhibited. SCC + MAL markedly reduced the phosphorylation of MAPK pathway factors along with Akt. HPLC analysis identified four marker compounds: isoquercitrin, astragalin, schizandrol A, and gomisin A. The extracts exerted remarkable synergistic effects as natural antithrombotic and antiplatelet agent and a potent drug candidate for treating cardiovascular diseases.

Cobalt Intoxication Heart Failure after Revision Total Hip Replacement for Ceramic Head Fracture: A Case Report.

In 1960s, toxic heart failure due to cobalt poisoning was firstly reported from Canadian industrial worker. Following development of bearing materials in hip arthroplasties, using cobalt-chrome alloy in bearing surface, there were rarely reported of systemic affect toxic cobaltism include toxic heart failure due to articulation wear in Western countries. It could be happened more easily by third body wear from ceramic particle especially revision total hip replacement (THR) surgery using cobalt-chrome alloy following ceramic articulation breakage which index surgery performed by ceramic on ceramic bearing. In Korea, due to many surgeons prefer ceramic on ceramic bearing in THR compared to Western countries, it might be more important issue within a time. However in our knowledge, there was no previous report about cobalt poisoning heart failure in Korea. It is still very rare and hard to diagnose cobalt intoxication heart failure after THR, so we report a case of fatal heart failure caused by cobalt intoxication after revision THR in 53-year old man who successfully underwent re-revision THR.

Psychological Vulnerability of Residents of Communities Affected by the Hebei Spirit Oil Spill.

OBJECTIVE: Psychological health is an important issue after disasters. This study aimed to investigate the prevalence of psychological symptoms among 993 residents of Taean District in South Korea after the Hebei Spirit oil spill and to examine determinants of vulnerability in residents' psychological symptoms. METHODS: Symptoms of post-traumatic stress (PTS), depression, suicidal ideation, and anxiety were assessed by questionnaires, and the responses were analyzed by using the survey analysis considering the sampling frame. RESULTS: Among the study subjects, the symptom prevalences of PTS, depression, suicidal ideation, and anxiety were 19.5%, 22.0%, 2.3%, and 4.2%, respectively, and symptoms were higher in people who were female, were older, were less educated, and had lower family income. People with fishery or related occupations compared to those with unrelated livelihoods and people residing in the vicinity of the oil band in the contaminated coastline showed additively increased symptom risks of PTS. Risk of suicidal ideation was predominantly increased in people with fishery or related occupations compared with those with unrelated livelihoods. CONCLUSIONS: Social supports, including compensation for income loss and community mental health programs, and longer follow-up studies are needed for residents in the communities affected by the Hebei Spirit oil spill.

Oxidative stress biomarkers in long-term participants in clean-up work after the Hebei Spirit oil spill.

BACKGROUND: The oil tanker Hebei Spirit spilled 12,547kL of oil near the western coastline of Korea on December 7, 2007. We aimed to investigate the relationship between oil spill exposure and oxidative stress in residents living near the affected area. METHODS: Study subjects were 671 residents who participated in a health examination between February and September 2009. As surrogates for oil spill exposure, we used the total duration of clean-up work and levels of urinary metabolites of polycyclic aromatic hydrocarbons (PAHs), 1-hydroxypyrene (1-OHP) and 2-naphthol (2-NAPH). Oxidative stress was measured using urinary levels of malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), indicators of lipid peroxidation and oxidative DNA damage, respectively. RESULTS: Levels of oxidative stress biomarkers were significantly increased with longer involvement in clean-up work over one year after the Hebei Spirit oil spill (MDA, p-trend<0.0001; 8-OHdG, p-trend<0.0001). As more time elapsed since the last involvement in clean-up, the total duration of clean-up work participation and levels of PAH metabolites (1-OHP and 2-NAPH), as well as levels of the oxidative stress biomarkers (MDA and 8-OHdG) decreased further. The level of 1-OHP had a significant positive correlation with the total duration of clean-up work involvement, with a higher level found in those who participated in clean-up for >100 days. Increasing levels of 1-OHP were significantly associated with increased MDA and 8-OHdG after adjusting for covariates, while the strength of association weakened as time passed since the last participation in clean-up work. The significance of the association was maintained for up to 12 months after the last clean-up work. CONCLUSIONS: The results suggested that oil exposure from prolonged clean-up activity likely induced oxidative stress in clean-up participants up to at least one year after the last exposure.

Attenuation of IFN-γ-induced B7-H1 expression by 15-deoxy-delta(12,14)-prostaglandin J2 via downregulation of the Jak/STAT/IRF-1 signaling pathway.

AIM: B7-H1, which belongs to the B7 family of costimulatory molecules, is implicated in the ability of tumors to evade the host immune response. The development of evasion mechanisms within the tumor microenvironment may be responsible for poor therapeutic responses. In this manuscript, we report that the 15-deoxy-δ(12,14)-prostaglandin J2 (15d-PGJ2), peroxisome proliferator-activated receptor gamma (PPARγ) activator leads to the downregulation of the cancer-associated expression of B7-H1 in response to interferon-gamma (IFN-γ) and the associated signaling cascades. MAIN METHODS: The expression of B7-H1 from IFN-γ-induced B16F10 melanoma cells was measured with flow cytometric analysis. The regulatory mechanisms of 15d-PGJ2 on cellular signaling pathways were examined using Western blot and electrophoretic mobility shift assays. KEY FINDINGS: The flow cytometric analysis revealed that the B7-H1 costimulatory molecule is significantly upregulated in B16F10 melanoma cells by stimulation with IFN-γ. However, 15d-PGJ2 strongly downregulates B7-H1 expression in IFN-γ-stimulated B16F10 melanoma cells. Furthermore, the significant damping effect of 15d-PGJ2 on B7-H1 expression involves the inhibition of the tyrosine phosphorylation of Janus kinase (Jak) and signal transducer(s) and activator(s) of transcription (STAT) and, thereby, the interferon regulatory factor-1 (IRF-1) trans-activation of STAT. These effects of 15d-PGJ2 were not abrogated by the PPARγ antagonist GW9662, indicating that they occur through a PPARγ-independent mechanism. SIGNIFICANCE: In this study, we demonstrate that 15d-PGJ2 suppresses the IFN-γ-elicited expression of B7-H1 by the inhibition of IRF-1 transcription via the Jak/STAT signaling pathway through a PPARγ-independent mechanism in mouse melanoma cells.

Respiratory effects of the hebei spirit oil spill on children in taean, Korea.

PURPOSE: The oil spill from the Heibei Spirit in December 2007 contaminated the Yellow Coast of South Korea. We evaluated the respiratory effects of that spill on children who lived along the Yellow Coast. METHODS: Of 662 children living in the area exposed to the oil spill, 436 (65.9%) were enrolled as subjects. All subjects completed a modified International Study of Asthma and Allergies in Childhood questionnaire. A health examination, including a skin prick test, pulmonary function test, and methacholine bronchial provocation test (MBPT), was administered. The children were assigned to two groups: those who lived close to the oil spill area and those who lived far from the oil spill area. RESULTS: The children who lived close to the oil spill area showed a significantly lower forced expiratory volume in one second (FEV1), an increased prevalence of 'asthma ever' (based on a questionnaire), and 'airway hyperresponsiveness' (based on the MBPT) than those who lived far from the oil spill area (FEV1; P=0.011, prevalence of 'asthma ever' based on a questionnaire; P=0.005, prevalence of 'airway hyperresponsiveness' based on the MBPT; P=0.001). The onset of wheezing after the oil spill was significantly higher in children who lived close to the oil spill area than in those who lived far from the oil spill area among the 'wheeze ever' group (P=0.002). In a multiple logistic regression analysis, male sex, family history of asthma, and residence near the oil spill area were significant risk factors for asthma (sex [male/female]: odds ratio [OR], 2.54; 95% confidence interval [CI], 1.31-4.91; family history of asthma [No/Yes]: OR, 3.77; 95% CI, 1.83-7.75; exposure group [low/high]; OR, 2.43; 95% CI, 1.27-4.65). CONCLUSIONS: This study suggests that exposure to an oil spill is a risk factor for asthma in children.

Burden of disease attributable to the Hebei Spirit oil spill in Taean, Korea.

OBJECTIVES: We aimed to assess the burden of disease (BOD) of the residents living in contaminated coastal area with oil spill and also analysed the BOD attributable to the oil spill by disease, age, sex and subregion. DESIGN: Health impact assessment by measuring years lived with disability (YLD) due to an oil spill. SETTING: A whole population of a community affected by an anthropogenic environmental disaster and secondary health outcome data. PARTICIPANTS: Based on the health outcome survey including 10 171 individuals (male 4354; female 5817), BOD of 66 473 populations (male 33 441; female 33 032) was measured. INTERVENTIONS: None. Observational study on the effect of a specific environmental health hazard. PRIMARY AND SECONDARY OUTCOME MEASURES: Using disability adjusted life year (DALY) method, BOD including physical and mental diseases was measured. For the BOD measurement, excess incidences of illnesses related to oil spill were estimated from the comparison of prevalence of the health outcomes between contaminated areas and reference area without contamination. RESULTS: YLD attributable to the oil spill were estimated to be 14 724 DALYs (male 7425 DALYs; female 7299 DALYs) for the year 2008. The YLD of mental diseases including post-traumatic stress disorder (PTSD) and depression for men were higher than that for women. The YLD for women was higher in asthma and allergies (rhinitis, dermatitis, conjunctivitis) than that for men. The effects of asthma and allergies were the greatest for people in their 40s, with the burden of mental illness being the greatest for those in their 20s. Proximity to the spill site was associated with increased BOD. CONCLUSIONS: An oil spill near a coastline can cause substantial adverse health effects. As the health effects of hazardous pollutants from oil spills are long-lasting, close follow-up studies are required to identify chronic health effects.

Activation of p38 mitogen-activated protein kinase is required for death receptor-independent caspase-8 activation and cell death in response to sphingosine.

Sphingosine induces activation of multiple signaling pathways that play critical roles in controlling cell death. However, the precise molecular mechanism of cell death induced by sphingosine remains to be clarified. In this study, we show that sphingosine induces death receptor-independent caspase-8 activation and apoptotic cell death via p38 mitogen-activated protein kinase (MAPK) activation and that suppression of the MAPK/extracellular signal-regulated kinase (ERK) kinase/ERK pathway by protein phosphatase 2A (PP2A) is required for p38 MAPK activation. Treatment of cells with sphingosine induced suppression of ERK and activation of p38 MAPK. Inhibition of p38 MAPK led to the marked suppression of death receptor-independent caspase-8 activation and subsequent cell death induced by sphingosine. Interestingly, pretreatment with phorbol 12-myristate 13-acetate or transfection of MAPK/ERK kinase/ERK resulting in ERK activation completely attenuated sphingosine-induced p38 MAPK activation. PP2A activity was additionally elevated on sphingosine treatment. Small interfering RNA targeting of PP2A effectively attenuated sphingosine-induced p38 MAPK activation through restoration of ERK activity, suggesting PP2A-mediated opposing regulation of ERK and p38 MAPK. Our findings clearly imply that activation of p38 MAPK promotes death receptor-independent activation of caspase-8 and apoptotic cell death pathways, thus providing a novel cellular mechanism for the anticancer activity of sphingolipid metabolites.

Opposing roles of c-Jun NH2-terminal kinase and p38 mitogen-activated protein kinase in the cellular response to ionizing radiation in human cervical cancer cells.

Exposure of cells to ionizing radiation induces activation of multiple signaling pathways that play critical roles in determining cell fate. However, the molecular basis for cell death or survival signaling in response to radiation is unclear at present. Here, we show opposing roles of the c-jun NH(2)-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) pathways in the mitochondrial cell death in response to ionizing radiation in human cervical cancer cells. Ionizing radiation triggered Bax and Bak activation, Bcl-2 down-regulation, and subsequent mitochondrial cell death. Inhibition of JNK completely suppressed radiation-induced Bax and Bak activation and Bcl-2 down-regulation. Dominant-negative forms of stress-activated protein kinase/extracellular signal-regulated kinase kinase 1 (SEK-1)/mitogen-activated protein kinase kinase-4 (MKK-4) inhibited JNK activation. Radiation also induced phosphoinositide 3-kinase (PI3K) activation. Interestingly, inhibition of PI3K effectively attenuated radiation-induced mitochondrial cell death and increased clonogenic survival. Inhibition of PI3K also suppressed SEK-1/MKK-4 and JNK activation, Bax and Bak activation, and Bcl-2 down-regulation. In contrast, inhibition of p38 MAPK led to enhanced Bax and Bak activation and mitochondrial cell death. RacN17, a dominant-negative form of Rac1, inhibited p38 MAPK activation and increased Bax and Bak activation. Exposure of cells to radiation also induced selective activation of c-Src among Src family kinases. Inhibition of c-Src by pretreatment with Src family kinase inhibitor PP2 or small interfering RNA targeting of c-Src attenuated radiation-induced p38 MAPK and Rac1 activation and enhanced Bax and Bak activation and cell death. Our results support the notion that the PI3K-SEK-1/MKK-4-JNK pathway is required for the mitochondrial cell death in response to radiation, whereas the c-Src-Rac1-p38 MAPK pathway plays a cytoprotective role against mitochondrial cell death.

Elevation of cyclin B1, active cdc2, and HuR in cervical neoplasia with human papillomavirus type 18 infection.

Over 30 cervical epitheliotrophic HPV types may lead to altered biological functions that affect the clinical outcome of HPV infection. In order to determine the regulatory mechanism and effect of different HPV subtypes, we performed functional assays on cdc2, cyclinB1 and HuR in human uterine cervical samples. After confirming 22 HPV types among 95 cervical swabs, 10 cervical tissues, and seven established cell lines using a DNA chip, we evaluated the functional activities of G2 molecules assays, that included; western blotting for cyclin B1, cdc2 and phospho-cdc2 (Y15 and T161), immunoprecipitation for cdc2, a nuclear extraction fractional assay, and RT-PCR for cyclin B1. The expression of cyclin B1 was found to be dependent on HPV type, and was particularly overexpressed in high-risk types, whereas cdc2 was ubiquitously expressed irrespective of HPV type. Phospho-cdc2 and cyclin B1, however, were most intense in HPV18 infected cervical samples. Furthermore, the HuR stabilizing factor of the cyclin B1 transcript was upregulated in HPV 18 infected swabs. Moreover, SiHa cell line showed weaker G2 functional activity than the HeLa cell line. This study demonstrates that HPV-18 decreases the fidelity of mitotic checkpoints and increases cdc2-associated histone H1 kinase activity relative to control populations, and further shows that the G2 checkpoint is aberrant by virtue of the stabilization of cyclin B1 mRNA through the upregulation of HuR protein and the functional form of cdc2, especially in cases with HPV 18 infected cervical lesions.

The orphan nuclear receptor SHP is involved in monocytic differentiation, and its expression is increased by c-Jun.

Small heterodimer partner (SHP) is an atypical member of nuclear receptor superfamily that lacks a DNA binding domain. Here, we show that SHP expression increases during monocytic differentiaton with exposure HL-60 leukemia cells to a 12-O-tetradecanoylphorbol-13-acetate (TPA) response element, whose treatment induced the SHP promoter activity dependent on c-Jun expression, which is well known to be involved in the commitment step in the TPA-induced differentiation of HL-60 leukemia cells. We also show that overexpression and activation signaling of c-Jun increase the SHP promoter activity, suggesting that the level of SHP expression is normally limiting for c-Jun-dependent monocytic differentiation. Electrophoretic mobility shift assays using oligonucleotides derived from the SHP promoter reveal that c-Jun exhibit TPA-induced DNA binding, providing a mechanism for the transcriptional activation of SHP gene expression. It was also found that overexpression of SHP and c-Jun greatly facilitated monocytic differentiation by TPA and surprisingly, that expression of SHP or c-Jun alone was sufficient to make cells differentiate into functionally mature monocytes, but silencing of SHP and c-Jun by RNA interference diminished the TPA-induced monocytic differentiation. Taken together, these works suggest that c-Jun works to activate the expression of SHP genes associated with the cascade regulation of monocytic differentiation.

Activation and interaction of ATF2 with the coactivator ASC-2 are responsive for granulocytic differentiation by retinoic acid.

Terminal differentiation of hematopoietic cells follows a precisely orchestrated program of transcriptional regulatory events at the promoters of both lineage-specific and ubiquitous genes. Here we show that the transcription factor ATF2 is associated with the induction of granulocytic differentiation, and the molecular interaction of ATF2 with a tissue-specific coactivator activating signal cointegator-2 (ASC-2) potentiates the differentiation procedure. All-trans retinoic acid (RA) induced the phosphorylation and expression of ATF2 in the early and middle phase of granulocyte differentiation, respectively. The activation of granulocyte-specific gene expression is increased with the concerted action of another basic regionleucine zipper factor, CCAAT/enhancer-binding protein (C/EBPalpha), and ASC-2, which function in a cooperative manner. The interaction between ATF2 and C/EBPalpha in RA-treated cells was enhanced by the ectopic expression of ASC-2. ATF2-mediated transactivation was also increased by co-transfection of ASC-2. This resulted from the direct protein interaction that the N-terminal transactivation domain of ATF2 interacts with the central region of ASC-2. Furthermore, the molecular interaction of ATF2 and ASC-2 was stimulated by RA treatment and inhibited by p38beta kinase inhibitor. Taking these results together, these results suggest that the differentiation-dependent expression and phosphorylation of ATF2 protein physically and functionally interacts with C/EBPalpha and coativator ASC-2 and synergizes to induce target gene transcription during granulocytic differentiation.

Interaction and functional cooperation of the cancer-amplified transcriptional coactivator activating signal cointegrator-2 and E2F-1 in cell proliferation.

Activating signal cointegrator-2 (ASC-2), a novel coactivator, is amplified in several cancer cells and known to interact with mitogenic transcription factors, including serum response factor, activating protein-1, and nuclear factor-kappaB, suggesting the physiological role of ASC-2 in the promotion of cell proliferation. Here, we show that the expression pattern of ASC-2 was correlated with that of E2F-1 for protein increases at G(1) and S phase. Furthermore, cells stably overexpressing ASC-2 had an increased cell proliferation profile. These results prompted us to examine the functional interaction of ASC-2 and E2F-1. Biochemical evidence of protein interaction indicated that the transactivation domain of E2F-1 interacted with the COOH-terminal region of ASC-2. The importance of the E2F-1-ASC-2 interaction was supported by the demonstration that the coexpression of ASC-2 and E2F-1 synergistically transactivated E2F-1-driven gene transcription and the acetylation of E2F-1 protein was necessary for ASC-2-mediated transcriptional coactivation. Interestingly, overexpression of ASC-2 increased the endogenous protein level of E2F-1 in cells, resulting from the prolonged protein stability of E2F-1. Taken together, these results suggest that the cancer-amplified transcriptional coactivator ASC-2 may promote cell proliferation through enhancement of E2F-1-dependent transactivation of the expression of genes associated with cell cycle progression that may be available to favor tumor growth in vivo.

Hepatitis B virus X protein regulates transactivation activity and protein stability of the cancer-amplified transcription coactivator ASC-2.

Hepatitis B virus X protein (HBx) is a transcriptional coactivator that plays a significant role in the regulation of genes involved in inflammation and cell survival. A recently identified cellular coactivator, activating signal cointegrator 2 (ASC-2), is enriched in liver cancer cells and associates with many transcription factors that are active in hepatocytes. The tissue colocalization of these 2 proteins, in view of their similar regulatory functions, led us to examine whether HBx and ASC-2 cooperate in transcriptional activation of gene expression. Glutathione S-transferase (GST) pull-down assays and mammalian 2-hybrid analysis show that the transactivation domain of HBx interacts with the C-terminal domain of ASC-2. In fact, these 2 proteins associated in a ternary complex that included the transcriptional activator retinoid X receptor (RXR). Mechanistically, on expression of HBx, the half-life of the ASC-2 coactivator is observed to increase in concordance with the observed increase in ASC-2-dependent coactivation of transcription. In conclusion, these results show that HBx stabilizes the cellular coactivator ASC-2 through direct protein-protein interaction, affecting the regulation of genes actively transcribed in liver cancer cells.