Radiosensitization of gliomas by intracellular generation of 5-fluorouracil potentiates prodrug activator gene therapy with a retroviral replicating vector.

A tumor-selective non-lytic retroviral replicating vector (RRV), Toca 511, and an extended-release formulation of 5-fluorocytosine (5-FC), Toca FC, are currently being evaluated in clinical trials in patients with recurrent high-grade glioma (NCT01156584, NCT01470794 and NCT01985256). Tumor-selective propagation of this RRV enables highly efficient transduction of glioma cells with cytosine deaminase (CD), which serves as a prodrug activator for conversion of the anti-fungal prodrug 5-FC to the anti-cancer drug 5-fluorouracil (5-FU) directly within the infected cells. We investigated whether, in addition to its direct cytotoxic effects, 5-FU generated intracellularly by RRV-mediated CD/5-FC prodrug activator gene therapy could also act as a radiosensitizing agent. Efficient transduction by RRV and expression of CD were confirmed in the highly aggressive, radioresistant human glioblastoma cell line U87EGFRvIII and its parental cell line U87MG (U87). RRV-transduced cells showed significant radiosensitization even after transient exposure to 5-FC. This was confirmed both in vitro by a clonogenic colony survival assay and in vivo by bioluminescence imaging analysis. These results provide a convincing rationale for development of tumor-targeted radiosensitization strategies utilizing the tumor-selective replicative capability of RRV, and incorporation of radiation therapy into future clinical trials evaluating Toca 511 and Toca FC in brain tumor patients

Follow-up of true visceral artery aneurysm after coil embolization by three-dimensional contrast-enhanced MR angiography

PURPOSE:We aimed to evaluate the outcomes of coil embolization of true visceral artery aneurysms by three-dimensional contrast-enhanced magnetic resonance (MR) angiography. MATERIALS AND METHODS:We used three-dimensional contrast-enhanced MR angiography, which included source images, to evaluate 23 patients (mean age, 60 years; range, 28–83 years) with true visceral artery aneurysms (splenic, n=15; hepatic, n=2; gastroduodenal, n=2; celiac, n=2; pancreaticoduodenal, n=1; gastroepiploic, n=1) who underwent coil embolization. Angiographic aneurysmal occlusion was revealed in all cases. Follow-up MR angiography was conducted with either a 1.5 or 3 Tesla system 3–25 months (mean, 18 months) after embolization. MR angiography was evaluated for aneurysmal occlusion, hemodynamic status, and complications. RESULTS:Complete aneurysmal occlusion was determined in 22 patients (96%) on follow-up MR angiography (mean follow-up period, 18 months). Neck recanalization, which was observed at nine and 20 months after embolization, was confirmed in one of eight patients (13%) using a neck preservation technique. In this patient, a small neck recanalization covered by a coil mass was demonstrated. The complete hemodynamic status after embolization was determined in 21 patients (91%); the visualization of several collateral vessels, such as short gastric arteries, after parent artery occlusion was poor compared with that seen on digital subtraction angiography in the remaining two patients (9%). An asymptomatic localized splenic infarction was confirmed in one patient (4%). CONCLUSION:Our study presents the follow-up results from three-dimensional contrast-enhanced MR angiography, which confirmed neck recanalization, the approximate hemodynamic status, and complications. This effective and less invasive method may be suitable for serial follow-up after coil embolization of true visceral aneurysms

Management of visceral artery embolization using 0.010-inch detachable microcoils

Transcatheter coil embolization is used primarily to treat arterial hemorrhages, tumors, aneurysms, and vascular malformations. However, conventional microcatheter systems cannot always be employed in difficult cases. In this technical note, we describe how small-diameter primary coils and microcatheter tips that are thinner than normal can be used to increase the safety and reliability of coil embolization

Multiple transcripts of Ca 2ϩ channel ␣ 1 -subunits and a novel spliced variant of the ␣ 1C -subunit in rat ductus arteriosus

3 H]thymidine incorporation, suggesting that L-and T-type Ca 2ϩ channels are involved in smooth muscle cell proliferation in the DA. Third, we found that a novel alternatively spliced variant of the ␣ 1C-isoform was highly expressed in the neointimal cushion of the DA, where proliferating and migrating smooth muscle cells are abundant. The basic channel properties of the spliced variant did not differ from those of the conventional ␣1C-subunit. We conclude that multiple VDCC subunits were identified in the DA, and, in particular, ␣ 1C-and ␣1G-subunits were predominant in the DA. A novel spliced variant of the ␣1C-subunit gene may play a distinct role in neointimal cushion formation in the DA. alternative spliced; development; gene expression; fetal circulation THE DUCTUS ARTERIOSUS (DA) is a fetal arterial connection between the pulmonary artery and the descending aorta. After birth, the DA closes immediately, in accordance with its smooth muscle contraction. An increase in oxygen tension and a dramatic decline in circulating prostaglandins are the most important triggers of DA contraction (5). Generally, vascular smooth muscle contraction is induced by Ca 2ϩ / calmodulin-dependent phosphorylation of the regulatory myosin light chain, which is mediated by an increase in intracellular Ca 2ϩ . Ca 2ϩ influx through voltage-dependent Ca 2ϩ channels (VDCCs) and Ca 2ϩ release from intracellular stores are major sources of this increase (8, 26). Thus VDCCs must play an important role in vascular myogenic reactivity and tone of the DA. VDCCs are classified, according to their distinct electrophysiological and pharmacological properties, into low (Ttype) and high (L-, N-, P-, Q-, and R-type) VDCCs (20, In addition to their role in determining contractile state, a growing body of evidence has demonstrated that VDCCs play an important role in regulating differentiation and remodeling of vascular smooth muscle cells (SMCs) (14, In the present study, we identified multiple VDCC subunits in the DA by semiquantitative and quantitative RT-PCR and immunodetection. In particular, ␣ 1C -and ␣ 1G -subunits were predominant in the DA. Furthermore, we will demonstrate the identification of a novel spliced variant of the ␣ 1C -subunit gene that may play a role in neointimal cushion formation of the DA

Structural insights into the HBV receptor and bile acid transporter NTCP

B型肝炎ウイルスの受容体“胆汁酸輸送体”の立体構造を解明. 京都大学プレスリリース. 2022-05-18.Roughly 250 million people are infected with hepatitis B virus (HBV) worldwide, and perhaps 15 million also carry the satellite virus HDV, which confers even greater risk of severe liver disease. Almost ten years ago the HBV receptor was identified as NTCP (sodium taurocholate co-transporting polypeptide), which interacts directly with the first 48 amino acid residues of the N-myristoylated N-terminal preS1 domain of the viral large (L) protein. Despite the pressing need for therapeutic agents to counter HBV, the structure of NTCP remains unsolved. This 349-residue protein is closely related to human apical sodium-dependent bile acid transporter (ASBT), another member of the solute carrier family SLC10. Crystal structures have been reported of similar bile acid transporters from bacteria, and these models with ten transmembrane helices are believed to resemble strongly both NTCP and ASBT. Using cryo-electron microscopy we have solved the structure of NTCP bound to an antibody, clearly showing the transporter has no equivalent to the first transmembrane helix of other SLC10 models, leaving the N-terminus exposed on the extracellular face. Comparison of the different structures indicates a common mechanism of bile acid transport, but the NTCP structure also displays a pocket formed by residues known to interact with preS1, presenting new and enticing opportunities for structure-based drug design

Interleukin-1 and tumor necrosis factor-α trigger restriction of hepatitis B virus infection via a cytidine deaminase activation-induced cytidine deaminase (AID).

金沢大学医薬保健研究域医学系Virus infection is restricted by intracellular immune responses in host cells, and this is typically modulated by stimulation of cytokines. The cytokines and host factors that determine the host cell restriction against hepatitis B virus (HBV) infection are not well understood. We screened 36 cytokines and chemokines to determine which were able to reduce the susceptibility of HepaRG cells to HBV infection. Here, we found that pretreatment with IL-1β and TNFα remarkably reduced the host cell susceptibility to HBV infection. This effect was mediated by activation of the NF-κB signaling pathway. A cytidine deaminase, activation-induced cytidine deaminase (AID), was up-regulated by both IL-1β and TNFα in a variety of hepatocyte cell lines and primary human hepatocytes. Another deaminase APOBEC3G was not induced by these proinflammatory cytokines. Knockdown of AID expression impaired the anti-HBV effect of IL-1β, and overexpression of AID antagonized HBV infection, suggesting that AID was one of the responsible factors for the anti-HBV activity of IL-1/TNFα. Although AID induced hypermutation of HBV DNA, this activity was dispensable for the anti-HBV activity. The antiviral effect of IL-1/TNFα was also observed on different HBV genotypes but not on hepatitis C virus. These results demonstrate that proinflammatory cytokines IL-1/TNFα trigger a novel antiviral mechanism involving AID to regulate host cell permissiveness to HBV infection