Antiplatelet drugs may increase the risk for checkpoint inhibitor-related pneumonitis in advanced cancer patients.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are indicated for various cancers and are the mainstay of cancer immunotherapy. They are often associated with ICI-related pneumonitis (CIP), however, hindering a favorable clinical course. Recently, non-oncology concomitant drugs have been reported to affect the efficacy and toxicity of ICIs; however, the association between these drugs and the risk for CIP is uncertain. The aim of this study was to assess the impact of baseline concomitant drugs on CIP incidence in ICI-treated advanced cancer patients. PATIENTS AND METHODS: This was a single-center retrospective study that included a cohort of 511 patients with advanced cancer (melanoma and non-small-cell lung, head and neck, genitourinary, and other types of cancer) treated with ICIs. Univariable analysis was conducted to identify baseline co-medications associated with CIP incidence. A propensity score matching analysis was used to adjust for potential CIP risk factors, and multivariable analysis was carried out to assess the impact of the identified co-medications on CIP risk. RESULTS: Forty-seven (9.2%) patients developed CIP. In these patients, the organizing pneumonia pattern was the dominant radiological phenotype, and 42.6% had grade ≥3 CIP, including one patient with grade 5. Of the investigated baseline co-medications, the proportion of antiplatelet drugs (n = 50, 9.8%) was higher in patients with CIP (23.4% versus 8.4%). After propensity score matching, the CIP incidence was higher in patients with baseline antiplatelet drugs (22% versus 6%). Finally, baseline antiplatelet drug use was demonstrated to increase the risk for CIP incidence regardless of cancer type (hazard ratio, 3.46; 95% confidence interval 1.21-9.86). CONCLUSIONS: An association between concomitant antiplatelet drug use at baseline and an increased risk for CIP was seen in our database. This implies the importance of assessing concomitant medications for CIP risk management.

Interleukin-6 and tumour necrosis factor-α cooperatively promote cell cycle regulators and proliferate rheumatoid arthritis fibroblast-like synovial cells.

Objective: To elucidate the roles of interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) in cell cycle regulation and proliferation of rheumatoid arthritis fibroblast-like synovial cells (RA-FLSs). Methods: Under stimulation with IL-6/soluble interleukin-6 receptor (sIL-6R) and TNF-α, we examined the expression of cell cycle regulators [p16INK4a, p21Cip1, p27Kip1, cyclin-dependent kinase-4 (CDK4), CDK6, Cyclin D, Cyclin E, and retinoblastoma protein (pRB)] by quantitative polymerase chain reaction, Western blotting, and immunofluorescence staining. The expression of pRB, with or without 10% foetal bovine serum, was examined by Western blotting. DNA synthesis and cell viability were examined by the BrdU assay and WST-8 assay, respectively. After transfection with siRNA/p16INK4a, siRNA/p21Cip1, siRNA/p27Kip1, siRNA/CDK4, or siRNA/CDK6, RA-FLSs were successively stimulated with or without IL-6/sIL-6R or TNF-α to determine cell viability. Results: IL-6/sIL-6R significantly decreased the expression of p16INK4a, and increased p21Cip1, Cyclin E1, CYCLIN D, and pRB. TNF-α decreased the expression of CDK4, and significantly increased p27Kip1, CDK6, Cyclin E1/E2, CYCLIN D, CYCLIN E, pRB, and phosphorylated pRB (phospho-pRB). By immunofluorescence staining, CYCLIN D and phospho-pRB were simultaneously stained in the single cell. In serum-free culture, the expression of pRB was apparently decreased. DNA synthesis and cell viability were significantly increased by IL-6/sIL-6R and TNF-α. Silencing of CDK6 attenuated the cell viability induced by IL-6 and TNF-α. Conclusion: The results indicate that IL-6 and TNF-α interact with each other in regulating the cell cycle and accelerate the proliferation of RA-FLSs.

Impact of histone demethylase KDM3A-dependent AP-1 transactivity on hepatotumorigenesis induced by PI3K activation.

Epigenetic gene regulation linked to oncogenic pathways is an important focus of cancer research. KDM3A, a histone H3 lysine 9 (H3K9) demethylase, is known to have a pro-tumorigenic function. Here, we showed that KDM3A contributes to liver tumor formation through the phosphatidylinositol 3-kinase (PI3K) pathway, which is often activated in hepatocellular carcinoma. Loss of Kdm3a attenuated tumor formation in Pik3ca transgenic (Tg) mouse livers. Transcriptome analysis of pre-cancerous liver tissues revealed that the expression of activator protein 1 (AP-1) target genes was induced by PI3K activation, but blunted upon Kdm3a ablation. Particularly, the expression of Cd44, a liver cancer stem marker, was regulated by AP-1 in a Kdm3a-dependent manner. We identified Cd44-positive hepatocytes with epithelial-mesenchymal transition-related expression profiles in the Pik3ca Tg liver and confirmed their in vivo tumorigenic capacity. Notably, the number and tumor-initiating capacity of Cd44-positive hepatocytes were governed by Kdm3a. As a mechanism in Kdm3a-dependent AP-1 transcription, Kdm3a recruited c-Jun to the AP-1 binding sites of Cd44, Mmp7 and Pdgfrb without affecting c-Jun expression. Moreover, Brg1, a component of the SWI/SNF chromatin remodeling complex, interacted with c-Jun in a Kdm3a-dependent manner and was bound to the AP-1 binding site of these genes. Finally, KDM3A and c-JUN were co-expressed in 33% of human premalignant lesions with PI3K activation. Our data suggest a critical role for KDM3A in the PI3K/AP-1 oncogenic axis and propose a novel strategy for inhibition of KDM3A against liver tumor development under PI3K pathway activation.

Sharpin promotes hepatocellular carcinoma progression via transactivation of Versican expression.

Sharpin (Shank-associated RH domain-interacting protein, also known as SIPL1) is a multifunctional molecule that participates in various biological settings, including nuclear factor-κB signaling activation and tumor suppressor gene inhibition. Sharpin is upregulated in various types of cancers, including hepatocellular carcinoma (HCC), and is implicated in tumor progression. However, the exact roles of Sharpin in tumorigenesis and tumor progression remain largely unknown. Here we report novel mechanisms of HCC progression through Sharpin overexpression. In our study, Sharpin was upregulated in human HCC tissues. Increased Sharpin expression enhanced hepatoma cell invasion, whereas decrease in Sharpin expression by RNA interference inhibited invasion. Microarray analysis identified that Versican, a chondroitin sulfate proteoglycan that plays crucial roles in tumor progression and invasion, was also upregulated in Sharpin-expressing stable cells. Versican expression increased in the majority of HCC tissues and knocking down of Versican greatly attenuated hepatoma cell invasion. Sharpin expression resulted in a significant induction of Versican transcription synergistically with Wnt/ß-catenin pathway activation. Furthermore, Sharpin-overexpressing cells had high tumorigenic properties in vivo. These results demonstrate that Sharpin promotes Versican expression synergistically with the Wnt/ß-catenin pathway, potentially contributing to HCC development. A Sharpin/Versican axis could be an attractive therapeutic target for this currently untreatable cancer.

Significant reduction in the incidence of C5 palsy after cervical laminoplasty using chilled irrigation water.

AIMS: The aim of this study was to determine whether chilled irrigation saline decreases the incidence of clinical upper limb palsy (ULP; a reduction of one grade or more on manual muscle testing; MMT), based on the idea that ULP results from thermal damage to the nerve roots by heat generated by friction during bone drilling. METHODS: Irrigation saline for drilling was used at room temperature (RT, 25.6°C) in open-door laminoplasty in 400 patients (RT group) and chilled to a mean temperature of 12.1°C during operations for 400 patients (low-temperature (LT) group). We assessed deltoid, biceps, and triceps brachii muscle strength by MMT. ULP occurring within two days post-operatively was categorised as early-onset palsy. RESULTS: The incidence of ULP (4.0% vs 9.5%, p = 0.003), especially early-onset palsy (1.0% vs 5.5%, p < 0.001), was significantly lower for the LT group than for the RT group. Multivariate analysis indicated that RT irrigation saline use, concomitant foraminotomy, and opened side were significant predictors for ULP. DISCUSSION: Using chilled irrigation saline during bone drilling significantly decreased the ULP incidence, particularly the early-onset type, and shortened the recovery period for ULP. Chilled irrigation saline can thus be recommended as a simple method for preventing ULP. TAKE HOME MESSAGE: Chilled irrigation during laminoplasty reduces C5 palsy.

Recurrent mutations of CD79B and MYD88 are the hallmark of primary central nervous system lymphomas.

AIMS: Primary central nervous system lymphoma (PCNSL) manifest aggressive clinical behaviour and have poor prognosis. Although constitutive activation of the nuclear factor-κB (NF-κB) pathway has been documented, knowledge about the genetic alterations leading to the impairment of the NF-κB pathway in PCNSLs is still limited. This study was aimed to unravel the underlying genetic profiles of PCNSL. METHODS: We conducted the systematic sequencing of 21 genes relevant to the NF-κB signalling network for 71 PCNSLs as well as the pyrosequencing of CD79B and MYD88 mutation hotspots in a further 35 PCNSLs and 46 glioblastomas (GBMs) for validation. RESULTS: The results showed that 68 out of 71 PCNSLs had mutations in the NF-κB gene network, most commonly affecting CD79B (83%), MYD88 (76%), TBL1XR1 (23%), PRDM1 (20%) and CREBBP1 (20%). These mutations, particularly CD79B and MYD88, frequently coincided within each tumour in various combinations, simultaneously affecting diverse pathways within the network. No GBMs had hotspot mutation of CD79B Y196 and MYD88 L265. CONCLUSIONS: The prevalence of CD79B and MYD88 mutations in PCNSLs was considerably higher than reported in systemic diffuse large B-cell lymphomas. This observation could reflect the paucity of antigen stimuli from the immune system in the central nervous system (CNS) and the necessity to substitute them by the constitutive activation of CD79B and MYD88 that would initiate the signalling cascades. These hotspot mutations may serve as a genetic hallmark for PCNSL serving as a genetic marker for diagnose and potential targets for molecular therapy.

(62)Cu-diacetyl-bis (N(4)-methylthiosemicarbazone) PET in human gliomas: comparative study with [(18)F]fluorodeoxyglucose and L-methyl-[(11)C]methionine PET.

BACKGROUND AND PURPOSE: (62)Cu-diacetyl-bis(N(4)-methylthiosemicarbazone) was developed as a hypoxic radiotracer in PET. We compared imaging features among MR imaging and (62)Cu-diacetyl-bis(N(4)-methylthiosemicarbazone)-PET, FDG-PET, and L-methyl-[(11)C]methionine)-PET in gliomas. MATERIALS AND METHODS: We enrolled 23 patients who underwent (62)Cu-diacetyl-bis(N(4)-methylthiosemicarbazone)-PET and FDG-PET and 19 (82.6%) who underwent L-methyl-[(11)C]methionine)-PET, with all 23 patients undergoing surgery and their diagnosis being then confirmed by histologic examination as a glioma. Semiquantitative and volumetric analysis were used for the comparison. RESULTS: There were 10 newly diagnosed glioblastoma multiforme and 13 nonglioblastoma multiforme (grades II and III), including 4 recurrences without any adjuvant treatment. The maximum standardized uptake value and tumor/background ratios of (62)Cu-diacetyl-bis(N(4)-methylthiosemicarbazone), as well as L-methyl-[(11)C]methionine, were significantly higher in glioblastoma multiforme than in nonglioblastoma multiforme (P = .03 and P = .03, respectively); no significant differences were observed on FDG. At a tumor/background ratio cutoff threshold of 1.9, (62)Cu-diacetyl-bis(N(4)-methylthiosemicarbazone) was most predictive of glioblastoma multiforme, with 90.0% sensitivity and 76.9% specificity. The positive and negative predictive values, respectively, for glioblastoma multiforme were 75.0% and 85.7% on (62)Cu-diacetyl-bis(N(4)-methylthiosemicarbazone), 83.3% and 60.0% on L-methyl-[(11)C]methionine, and 72.7% and 75.0% on MR imaging. In glioblastoma multiforme, volumetric analysis demonstrated that (62)Cu-diacetyl-bis(N(4)-methylthiosemicarbazone) uptake had significant correlations with FDG (r = 0.68, P = .03) and L-methyl-[(11)C]methionine (r = 0.87, P = .03). However, the (62)Cu-diacetyl-bis(N(4)-methylthiosemicarbazone)-active region was heterogeneously distributed in 50.0% (5/10) of FDG-active and 0% (0/6) of L-methyl-[(11)C]methionine)-active regions. CONCLUSIONS: (62)Cu-diacetyl-bis(N(4)-methylthiosemicarbazone) may be a practical radiotracer in the prediction of glioblastoma multiforme. In addition to FDG-PET, L-methyl-[(11)C]methionine)-PET, and MR imaging, (62)Cu-diacetyl-bis(N(4)-methylthiosemicarbazone)-PET may provide intratumoral hypoxic information useful in establishing targeted therapeutic strategies for patients with glioblastoma multiforme.

Application of 62Cu-diacetyl-bis (N4-methylthiosemicarbazone) PET imaging to predict highly malignant tumor grades and hypoxia-inducible factor-1α expression in patients with glioma.

BACKGROUND AND PURPOSE: Hypoxic tissue evaluation in glioma is important for predicting treatment response and establishing antihypoxia therapy. In this preliminary study, (62)Cu-ATSM PET was used to determine its validity as a biomarker for distinguishing tumor grade and tissue hypoxia. MATERIALS AND METHODS: (62)Cu-ATSM PET was performed in 22 patients with glioma, and the (62)Cu-ATSM SUV(max) and T/B ratio were semiquantitatively evaluated. (62)Cu-ATSM uptake distribution was qualitatively evaluated and compared with MR imaging findings. HIF-1α expression, a hypoxia marker, was compared with (62)Cu-ATSM uptake values. RESULTS: The (62)Cu-ATSM SUV(max) and T/B ratio were significantly higher in grade IV than in grade III gliomas (P = .014 and .018, respectively), whereas no significant differences were found between grade III and grade II gliomas. At a T/B ratio cutoff threshold of 1.8, (62)Cu-ATSM uptake was predictive of HIF-1α expression, with 92.3% sensitivity and 88.9% specificity. The mean T/B ratio was also significantly higher in HIF-1α-positive glioma tissue than in HIF-1α-negative tissue (P = .001). Using this optimal threshold of T/B ratio, (62)Cu-ATSM PET showed regional uptake in 61.9% (13/21) of tumors within the contrast-enhanced region on MR imaging, which was significantly correlated with presence of a necrotic component (P = .002). CONCLUSIONS: Our results demonstrated that (62)Cu-ATSM uptake is relatively high in grade IV gliomas and correlates with the MR imaging findings of necrosis. Moreover, the (62)Cu-ATSM T/B ratio showed significant correlation with HIF-1α expression. Thus, (62)Cu-ATSM appears to be a suitable biomarker for predicting highly malignant grades and tissue hypoxia in patients with glioma.

Inhibition of renin-angiotensin system affects prognosis of advanced pancreatic cancer receiving gemcitabine.

BACKGROUND: The renin-angiotensin system (RAS) is thought to have a role in carcinogenesis, and RAS inhibition may prevent tumour growth. METHODS: We retrospectively investigated the impact of angiotensin I-converting enzyme inhibitors (ACEIs) and angiotensin II type-1 receptor blockers (ARBs) in 155 patients with pancreatic cancer receiving gemcitabine monotherapy. Patients were divided into three groups: the ACEI/ARB group (27 patients receiving an ACEI or ARB for hypertension (HT)), the non-ACEI/ARB with HT group (25 patients receiving antihypertensive drugs other than ACEIs or ARBs), and the non-HT group (103 patients receiving no antihypertensive drugs). RESULTS: Patient characteristics were not different, except for age and HT medications. Progression-free survival (PFS) was 8.7 months in the ACEI/ARB group, 4.5 months in the non-ACEI/ARB with HT group, and 3.6 months in the non-HT group. Overall survival (OS) was 15.1 months in the ACEI/ARB group, 8.9 months in the non-ACEI/ARB with HT group, and 9.5 months in the non-HT group. The use of ACEIs/ARBs was a significant prognostic factor for both PFS (P=0.032) and OS (P=0.014) in the multivariate analysis. CONCLUSIONS: The ACEIs/ARBs in combination with gemcitabine might improve clinical outcomes in patients with advanced pancreatic cancer. Prospective trials are needed to test this hypothesis.

(2)H-decoupling-accelerated (1)H spin diffusion in dynamic nuclear polarization with photoexcited triplet electrons.

In dynamic nuclear polarization (DNP) experiments applied to organic solids for creating nonequilibrium, high (1)H spin polarization, an efficient buildup of (1)H polarization is attained by partially deuterating the material of interest with an appropriate (1)H concentration. In such a dilute (1)H spin system, it is shown that the (1)H spin diffusion rate and thereby the buildup efficiency of (1)H polarization can further be enhanced by continually applying radiofrequency irradiation for deuterium decoupling during the DNP process. As experimentally confirmed in this work, the electron spin polarization of the photoexcited triplet state is mainly transferred only to those (1)H spins, which are in the vicinity of the electron spins, and (1)H spin diffusion transports the localized (1)H polarization over the whole sample volume. The (1)H spin diffusion coefficients are estimated from DNP repetition interval dependence of the initial buildup rate of (1)H polarization, and the result indicates that the spin diffusion coefficient is enhanced by a factor of 2 compared to that without (2)H decoupling.

Compressive properties of cartilage-like tissues repaired in vivo with scaffold-free, tissue engineered constructs.

BACKGROUND: It is crucial to develop an effective methodology for restoring adequate compressive properties to osteoarthritic cartilage. We have developed a scaffold-free tissue engineered construct cultured from synovium-derived mesenchymal stem cells. However, the compressive properties of cartilage-like tissues repaired with the construct have not been fully determined. METHODS: Synovium-derived mesenchymal stem cells were cultured in Dulbecco's modified Eagle's medium to produce the tissue engineered construct. Implantation of the construct into cylindrically-shaped partial defects in femoral cartilage in an experimental porcine model was performed. Six months after implantation, cartilage-like tissues repaired with the construct were subjected to static and cyclic compression tests using a micro-unconfined compression test apparatus developed in our laboratory. FINDINGS: The developed apparatus was validated in preliminary examinations. The repaired tissues exhibited rate-dependent viscoelastic properties; the compressive modulus was slightly lower than that of normal cartilage at a rate of 4 microm/s, while no difference was observed at a rate of 100 microm/s. In contrast, the repaired tissue without the construct exhibited rate-independent, non-viscoelastic properties. In the cyclic compression test, however, the compressive strain was significantly larger in both repaired tissues as compared with normal cartilage. INTERPRETATION: Although the quasi-static compressive properties of the repaired tissue with the construct, indicating rate-dependent and viscoelastic behaviors, are comparable to normal cartilage, the cyclic compressive strain increases more rapidly than in normal cartilage. It is suggested that the differences between the tissues and normal cartilage are attributable to the increased permeability of the extracellular matrix.

Comparison of human serum with fetal bovine serum for expansion and differentiation of human synovial MSC: potential feasibility for clinical applications.

The aim of this study was to evaluate the effect of human serum (HS) on growth and differentiation capacity of human synovium-derived mesenchymal stem cells (MSC) in comparison to cells grown in fetal bovine serum (FBS). Human MSCs were isolated from the synovium of knee joints of three donors and the cells were cultured individually in varying concentrations of allogenic HS or FBS. Bovine MSCs were isolated from synovium and cultured in the same manner. Cell proliferation was assessed by the tetrazolium assay after passage 3. The capacity for chondrogenic and osteogenic differentiation was investigated in specific media followed by 1,9-dimethylmethylene blue assay and alcian blue staining, or by alizarin red staining, respectively. Human MSCs proliferated significantly more rapidly in the presence of HS than with equivalent levels of FBS. Chondrogenic or osteogenic differentiation occurred to nearly identical levels in HS or FBS. The results of this study indicate that HS is superior for the culture of human MSCs compared with FBS in terms of cellular expandability, without losing chondrogenic or osteogenic differentiation capacity. Coupled with the advantage in eliminating the potential risk accompanied with the use of xeno-derived materials, pooled, well-characterized HS could be a useful reagent to promote cellular expansion for clinical synovial stem cell-based therapy.

The immunosuppressant FK506 promotes development of the chondrogenic phenotype in human synovial stromal cells via modulation of the Smad signaling pathway.

OBJECTIVE: To assess the effect of the immunosuppressant FK506 on chondrogenic differentiation of human synovial stromal cells (hSSCs). METHODS: hSSCs were isolated from synovium of the knee joint and 2x10(5) cells were subjected to pellet culture in chondrogenic culture medium for 3 weeks with or without growth factors [bone morphogenetic protein 2 (BMP2) or transforming growth factor beta(1) (TGFbeta(1))] and +/- addition of FK506 in chondrogenic culture media was evaluated. Chondrogenesis was assessed by the size of the pellet, the production of proteoglycans, and messenger RNA (mRNA) levels for chondrogenic markers. Furthermore, levels and intracellular location of phosphorylated Smad proteins related to BMP signaling and TGFbeta signaling were evaluated following exposure to FK506. RESULTS: FK506 enhanced the differentiation of hSSCs toward a chondrogenic phenotype in a dose-dependent manner associated with increases in glycosaminoglycan synthesis and increased mRNA levels for chondrogenic marker genes. Additionally, FK506 further enhanced chondrogenesis of synovial stromal cells (SSCs) induced by BMP2 and TGFbeta(1), also in a dose-dependent manner. Notably, phosphorylation of Smad1/5/8 and Smad3 was significantly increased by FK506. Also, the ratio of nuclear translocation to cytoplasmic levels of phosphorylated Smad1/5/8 and Smad3 were increased following exposure of SSCs to FK506. Moreover, inhibition of Smad signaling significantly abrogated FK506-induced chondrogenic differentiation of SSCs. CONCLUSION: This study demonstrated that FK506 promotes chondrogenic differentiation of hSSCs likely via impact on Smad signaling pathways. With further optimization, FK506 could potentially be a unique therapeutic tool to promote cartilage repair in clinical situations, as well as enhance development of tissue engineered cartilage in vitro.

Absence of PIK3CA hotspot mutations in hepatocellular carcinoma in Japanese patients.

A recent study revealed that the p110alpha (PIK3CA), catalytic subunit of phosphatidylinositol 3-kinase (PI3K), is somatically mutated in many types of cancer. For example, PIK3CA is mutated in an estimated 35.6% of hepatocellular carcinoma (HCC) cases. To measure the frequency of PIK3CA hotspot mutations in Japanese HCC patients, exons 9 and 20 of the PIK3CA gene were sequenced in 47 clinical HCC samples. Contrary to expectations, no hotspot mutations were found any of the HCC samples. In addition, we found abnormally migrating waves near the end of exon 9 in the PCR chromatograms from 13 of the 47 samples. PCR amplification and subsequent cloning and sequencing revealed that these chromatograms contained two distinct sequences, the wild-type p110alpha sequence and a different sequence found on human chromosome 22q11.2, the Cat Eye Syndrome region, which contains a putative pseudogene of PIK3CA. These abnormally migrating waves were also found in noncancerous liver tissue, indicating that this was not a result of HCC-associated mutations. Therefore, it is likely that the percentage of hotspot mutations in the PIK3CA gene of Japanese HCC patients is lower than was previously reported.

The hepatitis B virus X protein enhances AP-1 activation through interaction with Jab1.

Hepatitis B virus X protein (HBx) has many cellular functions and is a major factor in hepatitis and hepatocellular carcinoma caused by HBV infection. A proteomic approach was used to search for HBx-interacting proteins in order to elucidate the molecular mechanism of hepatocarcinogenesis. HBx was attached to myc and flag tags (MEF tags) and expressed in 293T cells; the protein complex formed within the cells was purified and characterized by mass spectrometry. COP9 signalosome (CSN) subunits 3 and 4 were subsequently identified as HBx-interacting proteins. In addition, CSN subunit 5, Jun activation domain-binding protein 1 (Jab1), was shown to be a novel cellular target of HBx. In vivo and in vitro interactions between HBx and Jab1 were confirmed by standard immunoprecipitation and GST pull-down assays. An analysis of HBx deletion constructs showed that amino acids 30-125 of HBx were responsible for binding to Jab1. Confocal laser microscopy demonstrated that HBx was mainly localized in the cytoplasm, while Jab1 was found mainly in the nucleus and partially in the cytoplasm, and that the two proteins colocalized in the cytoplasm. The cotransfection of HBx and Jab1 resulted in substantial activator protein 1 (AP-1) activation and knockdown of endogenous Jab1 attenuated AP-1 activation caused by HBx. In addition, the coexpression of HBx and Jab1 potentiated phosphorylation of JNK, leading to the subsequent phosphorylation of c-Jun, whereas the level of c-Jun and JNK phosphorylation induced by HBx was decreased in Jab1 knockdown cells. These results suggest that the interaction between HBx and Jab1 enhances HBx-mediated AP-1 activation.

Effect of growth hormone on high plasma levels of glucagon-like peptide-1 (GLP-1) in hypophysectomized rats.

Fasting plasma GLP-1 levels were significantly higher in hypophysectomized (hypox) rats (n = 6) than in intact (normal) rats (n = 7) (54.3 +/- 5.2 vs. 33.3 +/- 2.4 pmol/L, p < 0.001). To examine the influence of pituitary hormones on plasma GLP-1 levels, concentrations of plasma glucose, insulin and GLP-1 after an oral glucose load to hypox rats that were given either rat growth hormone (rGH) (n = 7), cortisol and thyroxine (n = 7) or no substitution (n = 6) were compared with those of normal rats (n = 7). Plasma glucose levels in the fasting state and after the glucose ingestion were significantly lower in hypox rats, but the hormonal replacements to hypox rats increased their total glucose levels to those of normal rats, although the increasing patterns were different from those in normal rats. Insulin levels both in the fasting state and after the glucose ingestion were significantly decreased in hypox rats and the fasting and total GLP-1 levels were significantly increased in those rats. rGH substitution significantly increased the total insulin levels in hypox rats and decreased the fasting and total GLP-1 levels closely to levels in normal rats, while substitution with cortisol and thyroxine failed to introduce such a significant effect. These results suggested that secretion of GLP-1 might be influenced by the function of GH.

Acute disseminated encephalomyelitis confined to brainstem.

A 21-year-old man was troubled with a subacute history of brainstem involvement and a leukocyte pleocytosis in the cerebrospinal fluid. Magnetic resonance imaging (MRI) demonstrated a massive lesion with Gd enhancement in the pons. Steroid therapy, not antiviral drugs, was dramatically effective for the mass reduction and symptom improvement. Over 4 years no recurrence has been recognized, so this case was diagnosed to be an unusual case of acute disseminated encephalomyelitis (ADEM). ADEM must be included in the differential diagnosis for a brainstem mass in MRI.

The NEDD8 system is essential for cell cycle progression and morphogenetic pathway in mice.

NEDD8/Rub1 is a ubiquitin (Ub)-like molecule that covalently ligates to target proteins through an enzymatic cascade analogous to ubiquitylation. This modifier is known to target all cullin (Cul) family proteins. The latter are essential components of Skp1/Cul-1/F-box protein (SCF)-like Ub ligase complexes, which play critical roles in Ub-mediated proteolysis. To determine the role of the NEDD8 system in mammals, we generated mice deficient in Uba3 gene that encodes a catalytic subunit of NEDD8-activating enzyme. Uba3(-/-) mice died in utero at the periimplantation stage. Mutant embryos showed selective apoptosis of the inner cell mass but not of trophoblastic cells. However, the mutant trophoblastic cells could not enter the S phase of the endoreduplication cycle. This cell cycle arrest was accompanied with aberrant expression of cyclin E and p57(Kip2). These results suggested that the NEDD8 system is essential for both mitotic and the endoreduplicative cell cycle progression. beta-Catenin, a mediator of the Wnt/wingless signaling pathway, which degrades continuously in the cytoplasm through SCF Ub ligase, was also accumulated in the Uba3(-/-) cytoplasm and nucleus. Thus, the NEDD8 system is essential for the regulation of protein degradation pathways involved in cell cycle progression and morphogenesis, possibly through the function of the Cul family proteins.