A phase I/II study evaluating the pharmacokinetics, pharmacodynamics, and safety of drospirenone as an oral contraceptive in Japanese women.

AIM: Drospirenone (DRSP) is a synthetic progestogen approved as a progestin-only pill for contraception in both the United States and Europe. Herein, we conducted a phase I/II study to evaluate the pharmacokinetics, pharmacodynamics, and safety of DRSP in Japanese women. METHODS: Single and multiple doses of 4 mg of DRSP were orally administered to healthy premenopausal Japanese women. In the multiple-dose period, 4 mg of DRSP was administered once daily for 24 days. Pharmacokinetics, hormone levels, and adverse events (AEs) were investigated. RESULTS: Twelve Japanese women participated in this study. The single- and multiple-dose pharmacokinetics of DRSP was similar to that reported in previous studies in Caucasians. In the multiple-dose period, no subject displayed a progesterone level of more than 5.03 ng/mL. AEs were observed in 11 (91.7%) subjects. The most common AE was genital hemorrhage, which was observed in six (50.0%) subjects, followed by diarrhea and acne in four (33.3%) subjects each. All AEs resolved or improved at the end of the study, and complete recovery was confirmed in all subjects at follow-up. CONCLUSIONS: The pharmacokinetics of DRSP in Japanese women was similar to that of previous studies performed in Caucasian women. Repeated administration of DRSP maintained low plasma progesterone levels indicating effective inhibition of ovulation. No notable safety concerns were observed. In this phase I/II study, DRSP had no obvious pharmacokinetic, pharmacodynamic, or safety issues to consider in Japanese women.

COVID-19 vaccine effectiveness against severe COVID-19 requiring oxygen therapy, invasive mechanical ventilation, and death in Japan: A multicenter case-control study (MOTIVATE study).

INTRODUCTION: Since the SARS-CoV-2 Omicron variant became dominant, assessing COVID-19 vaccine effectiveness (VE) against severe disease using hospitalization as an outcome became more challenging due to incidental infections via admission screening and variable admission criteria, resulting in a wide range of estimates. To address this, the World Health Organization (WHO) guidance recommends the use of outcomes that are more specific to severe pneumonia such as oxygen use and mechanical ventilation. METHODS: A case-control study was conducted in 24 hospitals in Japan for the Delta-dominant period (August-November 2021; "Delta") and early Omicron (BA.1/BA.2)-dominant period (January-June 2022; "Omicron"). Detailed chart review/interviews were conducted in January-May 2023. VE was measured using various outcomes including disease requiring oxygen therapy, disease requiring invasive mechanical ventilation (IMV), death, outcome restricting to "true" severe COVID-19 (where oxygen requirement is due to COVID-19 rather than another condition(s)), and progression from oxygen use to IMV or death among COVID-19 patients. RESULTS: The analysis included 2125 individuals with respiratory failure (1608 cases [75.7%]; 99.2% of vaccinees received mRNA vaccines). During Delta, 2 doses provided high protection for up to 6 months (oxygen requirement: 95.2% [95% CI:88.7-98.0%] [restricted to "true" severe COVID-19: 95.5% {89.3-98.1%}]; IMV: 99.6% [97.3-99.9%]; fatal: 98.6% [92.3-99.7%]). During Omicron, 3 doses provided high protection for up to 6 months (oxygen requirement: 85.5% [68.8-93.3%] ["true" severe COVID-19: 88.1% {73.6-94.7%}]; IMV: 97.9% [85.9-99.7%]; fatal: 99.6% [95.2-99.97]). There was a trend towards higher VE for more severe and specific outcomes. CONCLUSION: Multiple outcomes pointed towards high protection of 2 doses during Delta and 3 doses during Omicron. These results demonstrate the importance of using severe and specific outcomes to accurately measure VE against severe COVID-19, as recommended in WHO guidance in settings of intense transmission as seen during Omicron.

HERTHENA-Lung01: a phase II study of patritumab deruxtecan (HER3-DXd) in previously treated metastatic EGFR-mutated NSCLC.

Limited treatment options exist for EGFR-mutated NSCLC that has progressed after EGFR TKI and platinum-based chemotherapy. HER3 is highly expressed in EGFR-mutated NSCLC, and its expression is associated with poor prognosis in some patients. Patritumab deruxtecan (HER3-DXd) is an investigational, potential first-in-class, HER3-directed antibody-drug conjugate consisting of a HER3 antibody attached to a topoisomerase I inhibitor payload via a tetrapeptide-based cleavable linker. In an ongoing phase I study, HER3-DXd demonstrated promising antitumor activity and a tolerable safety profile in patients with EGFR-mutated NSCLC, with or without identified EGFR TKI resistance mechanisms, providing proof of concept of HER3-DXd. HERTHENA-Lung01 is a global, registrational, phase II trial further evaluating HER3-DXd in previously treated advanced EGFR-mutated NSCLC. Clinical Trial Registration: NCT04619004 (ClinicalTrials.gov); 2020-000730-17 (EudraCT).

This article describes a clinical trial of a new drug to treat non-small-cell lung cancer. About a third of patients with non-small-cell lung cancer have tumors with changes (mutations) in a gene called EGFR, which cause tumors to grow. These patients are treated with EGFR inhibitors and chemotherapy, both of which can stop the tumor from growing for a period of time. When these treatments stop working, new and effective treatments are needed. Most non-small-cell lung cancer tumors have a protein called HER3 on the surface of their cells. Patritumab deruxtecan (HER3-DXd) is a new drug candidate that uses HER3 to get chemotherapy inside tumor cells. In an earlier clinical trial for patients with lung cancer whose disease had grown after multiple treatments, HER3-DXd often shrank tumors or stopped them from growing. The side effects of HER3-DXd were tolerable. The clinical trial described in this publication, HERTHENA-Lung01 (NCT04619004), is testing HER3-DXd in a larger group of patients with non-small-cell lung cancer that has activating mutations in the EGFR gene and for whom previous treatments have stopped working. The results of this study will help doctors and regulators decide if HER3-DXd should be approved and used for patients with non-small-cell lung cancer with EGFR mutations.

Integrative biomarker analyses indicate etiological variations in hepatocellular carcinoma.

BACKGROUND & AIMS: The purpose of this study was to determine whether biomarkers from baseline plasma and archival tissue specimens collected from patients enrolled in the EVOLVE-1 trial - a randomized phase 3 study of everolimus in hepatocellular carcinoma (HCC) - were associated with prognosis, etiology or ethnicity. METHODS: Circulating plasma levels of bFGF, PLGF, VEGF, VEGF-D, c-Kit, collagen IV, sVEGFR1 and VEGFR2 were measured by ELISA (N=503). Protein levels of IGF-1R, c-Met, mTOR, Tsc2 were assayed by immunohistochemistry (N=125). Genomic DNA sequencing was conducted on a panel of 287 cancer-related genes (N=69). RESULTS: Patients with baseline plasma concentrations of VEGF or sVEGFR1 above the cohort median had significantly shorter overall survival. These plasma biomarkers retained prognostic significance in a multivariate Cox regression model with geographic region, macroscopic vascular invasion and alpha fetoprotein AFP levels. Membranous c-Met protein levels were significantly lower for Asian patients, as well as for hepatitis B viral etiology. The prevalence of genetic changes were similar to previous reports, along with a trend towards higher PTEN and TSC2 mutations among Asians. CONCLUSIONS: The angiogenesis biomarkers VEGF and sVEGFR1 were independent prognostic predictors of survival in patients with advanced HCC. Potential differences in c-Met and mTOR pathway activation between Asian and non-Asian patients should be considered in future clinical trials. LAY SUMMARY: Our study demonstrates that circulating angiogenesis biomarkers can predict the survival outcome in patients with advanced hepatocellular carcinoma independent of the clinical variables. There is etiology and ethnicity variation in molecular pathway activation in hepatocellular carcinoma, which should be considered for future clinical trial design of targeted therapy. CLINICAL TRIAL REGISTRATION NUMBER: NCT01035229.

Registration and Summation of Respiratory-Gated or Breath-Hold PET Images Based on Deformation Estimation of Lung from CT Image.

Lung motion due to respiration causes image degradation in medical imaging, especially in nuclear medicine which requires long acquisition times. We have developed a method for image correction between the respiratory-gated (RG) PET images in different respiration phases or breath-hold (BH) PET images in an inconsistent respiration phase. In the method, the RG or BH-PET images in different respiration phases are deformed under two criteria: similarity of the image intensity distribution and smoothness of the estimated motion vector field (MVF). However, only these criteria may cause unnatural motion estimation of lung. In this paper, assuming the use of a PET-CT scanner, we add another criterion that is the similarity for the motion direction estimated from inhalation and exhalation CT images. The proposed method was first applied to a numerical phantom XCAT with tumors and then applied to BH-PET image data for seven patients. The resultant tumor contrasts and the estimated motion vector fields were compared with those obtained by our previous method. Through those experiments we confirmed that the proposed method can provide an improved and more stable image quality for both RG and BH-PET images.

Investigation and treatment of pulmonary embolism as a potential etiology may be important to improve post-resuscitation prognosis in non-shockable out-of-hospital cardiopulmonary arrest: report on an analysis of the SOS-KANTO 2012 study.

Background: The prognosis of non-shockable out-of-hospital cardiac arrest is worse than that of shockable out-of-hospital cardiac arrest. We investigated the associations between the etiology and prognosis of non-shockable out-of-hospital cardiac arrest patients who experienced the return of spontaneous circulation after arriving at hospital. Methods and Results: All subjects were extracted from the SOS-KANTO 2012 study population. The subjects were 3,031 adults: (i) who had suffered out-of-hospital cardiac arrest, (ii) for whom there were no pre-hospital data on ventricular fibrillation/pulseless ventricular tachycardia until arrival at hospital, (iii) who experienced the return of spontaneous circulation after arriving at hospital. We compared the patients' prognosis after 1 and 3 months between various etiological and presumed cardiac factors. The proportion of the favorable brain function patients that developed pulmonary embolism or incidental hypothermia was significantly higher than that of the patients with presumed cardiac factors (1 month, P < 0.0001 and P < 0.0001, respectively; 3 months, P = 0.0018 and P < 0.0001, respectively). In multiple logistic regression analysis, pulmonary embolism and incidental hypothermia were found to be significant independent prognostic factors for 1- and 3-month survival and the favorable brain function rate. Conclusions: In patients who suffer non-shockable out-of-hospital cardiac arrest, but who experience the return of spontaneous circulation after arriving at hospital, the investigation and treatment of pulmonary embolism as a potential etiology may be important for improving post-resuscitation prognosis.

An interconnected hierarchical model of cell death regulation by the BCL-2 family.

Multidomain pro-apoptotic BAX and BAK, once activated, permeabilize mitochondria to trigger apoptosis, whereas anti-apoptotic BCL-2 members preserve mitochondrial integrity. The BH3-only molecules (BH3s) promote apoptosis by either activating BAX-BAK or inactivating anti-apoptotic members. Here, we present biochemical and genetic evidence that NOXA is a bona fide activator BH3. Using combinatorial gain-of-function and loss-of-function approaches in Bid(-/-)Bim(-/-)Puma(-/-)Noxa(-/-) and Bax(-/-)Bak(-/-) cells, we have constructed an interconnected hierarchical model that accommodates and explains how the intricate interplays between the BCL-2 members dictate cellular survival versus death. BID, BIM, PUMA and NOXA directly induce stepwise, bimodal activation of BAX-BAK. BCL-2, BCL-XL and MCL-1 inhibit both modes of BAX-BAK activation by sequestering activator BH3s and 'BH3-exposed' monomers of BAX-BAK, respectively. Furthermore, autoactivation of BAX and BAK can occur independently of activator BH3s through downregulation of BCL-2, BCL-XL and MCL-1. Our studies lay a foundation for targeting the BCL-2 family for treating diseases with dysregulated apoptosis.

Asparagine plays a critical role in regulating cellular adaptation to glutamine depletion.

Many cancer cells consume large quantities of glutamine to maintain TCA cycle anaplerosis and support cell survival. It was therefore surprising when RNAi screening revealed that suppression of citrate synthase (CS), the first TCA cycle enzyme, prevented glutamine-withdrawal-induced apoptosis. CS suppression reduced TCA cycle activity and diverted oxaloacetate, the substrate of CS, into production of the nonessential amino acids aspartate and asparagine. We found that asparagine was necessary and sufficient to suppress glutamine-withdrawal-induced apoptosis without restoring the levels of other nonessential amino acids or TCA cycle intermediates. In complete medium, tumor cells exhibiting high rates of glutamine consumption underwent rapid apoptosis when glutamine-dependent asparagine synthesis was suppressed, and expression of asparagine synthetase was statistically correlated with poor prognosis in human tumors. Coupled with the success of L-asparaginase as a therapy for childhood leukemia, the data suggest that intracellular asparagine is a critical suppressor of apoptosis in many human tumors.

Spontaneous rupture of a dissecting aneurysm in the superior rectal artery of a patient with neurofibromatosis type 1: a case report.

INTRODUCTION: Neurofibromatosis type 1 is an autosomal dominant disease primarily characterized by cutaneous café au lait spots, benign cutaneous neurofibromas, tumors of the central and peripheral nervous system, multiple skeletal abnormalities, and vascular abnormalities. CASE PRESENTATION: Here we describe the case of a 39-year-old Japanese man with neurofibromatosis type 1 complicated by the rupture of a dissecting aneurysm in his superior rectal artery. Our patient presented with temporary loss of consciousness and acute abdominal pain. Hemorrhagic shock and anemia were diagnosed based on a physical examination and laboratory investigations, and rapid infusion of Ringer's lactate solution was initiated. Contrast-enhanced abdominal computed tomography revealed hemorrhagic ascites with effusion of radiopaque dye into his pelvic cavity. A ruptured aneurysm was suspected in his superior rectal artery and selective angiography of the inferior mesenteric artery confirmed this diagnosis. Transcatheter arterial embolization was successfully performed and our patient was discharged 15 days after admission, with good recovery of his hemoglobin level, and no further hemorrhage or abdominal pain. CONCLUSION: This case of spontaneous rupture of a dissecting aneurysm in the peripheral blood supply strongly suggests the involvement of multiple blood vessel abnormalities in neurofibromatosis type 1. Patients with neurofibromatosis type 1 should undergo regular review given their overall health and the risk of fatality in vasculopathy associated with this disease.

Inhibition of Crm1-p53 interaction and nuclear export of p53 by poly(ADP-ribosyl)ation.

Poly(ADP-ribose) polymerase 1 (PARP-1) and p53 are two key proteins in the DNA-damage response. Although PARP-1 is known to poly(ADP-ribosyl)ate p53, the role of this modification remains elusive. Here, we identify the major poly(ADP-ribosyl)ated sites of p53 by PARP-1 and find that PARP-1-mediated poly(ADP-ribosyl)ation blocks the interaction between p53 and the nuclear export receptor Crm1, resulting in nuclear accumulation of p53. These findings molecularly link PARP-1 and p53 in the DNA-damage response, providing the mechanism for how p53 accumulates in the nucleus in response to DNA damage. PARP-1 becomes super-activated by binding to damaged DNA, which in turn poly(ADP-ribosyl)ates p53. The nuclear export machinery is unable to target poly(ADP-ribosyl)ated p53, promoting accumulation of p53 in the nucleus where p53 exerts its transactivational function.

Physical and functional interaction between mortalin and Mps1 kinase.

Mortalin is a member of Hsp70 chaperoning protein family involved in various cellular functions. Through the search of the kinases that mortalin physically interact with, we identified Mps1 as such a kinase. Mps1 kinase has been implicated in the regulation of centrosome duplication and mitotic checkpoint response. Mortalin binds to Mps1, and is phosphorylated by Mps1 on Thr62 and Ser65. The phosphorylated mortalin then super-activates Mps1 in a feedback manner. Mortalin has been previously shown to localize to centrosomes, and to be involved in the regulation of centrosome duplication. We found that centrosomal localization of mortalin depends on the presence of Mps1. Moreover, Mps1-associated acceleration of centrosome duplication depends on the presence of mortalin and super-activation by the Thr62/Ser65 phosphorylated mortalin.

Haploinsufficiency of poly(ADP-ribose) polymerase-1-mediated poly(ADP-ribosyl)ation for centrosome duplication.

The centrosome plays a vital role in maintaining chromosomal stability. Known as the microtubule organizing center, the centrosome is involved in the formation of spindle poles during mitosis, which ensures the distribution of the correct number of chromosomes to daughter cells. Aberrant centrosome duplication could cause centrosome amplification and chromosomal instability. We have previously shown that poly(ADP-ribose) polymerase-1 (PARP-1) is important for centrosome function and chromosomal stability. In this study, we used PARP-1(+/+), PARP-1(+/-) and PARP-1(-/-) primary mouse embryonic fibroblasts and found that the level of PARP-1 gene dosage correlates with PARP activity and the in vivo level of poly(ADP-ribosyl)ation, which could explain the mechanism by which PARP-1 haploinsufficiency affects centrosome duplication and chromosomal stability. Our results emphasize that correct regulation of poly(ADP-ribosyl)ation levels in vivo is important for maintenance of proper centrosome duplication and chromosomal stability.

Interaction between ROCK II and nucleophosmin/B23 in the regulation of centrosome duplication.

Nucleophosmin (NPM)/B23 has been implicated in the regulation of centrosome duplication. NPM/B23 localizes between two centrioles in the unduplicated centrosome. Upon phosphorylation on Thr(199) by cyclin-dependent kinase 2 (CDK2)/cyclin E, the majority of centrosomal NPM/B23 dissociates from centrosomes, but some NPM/B23 phosphorylated on Thr(199) remains at centrosomes. It has been shown that Thr(199) phosphorylation of NPM/B23 is critical for the physical separation of the paired centrioles, an initial event of the centrosome duplication process. Here, we identified ROCK II kinase, an effector of Rho small GTPase, as a protein that localizes to centrosomes and physically interacts with NPM/B23. Expression of the constitutively active form of ROCK II promotes centrosome duplication, while down-regulation of ROCK II expression results in the suppression of centrosome duplication, especially delaying the initiation of centrosome duplication during the cell cycle. Moreover, ROCK II regulates centrosome duplication in its kinase and centrosome localization activity-dependent manner. We further found that ROCK II kinase activity is significantly enhanced by binding to NPM/B23 and that NPM/B23 acquires a higher binding affinity to ROCK II upon phosphorylation on Thr(199). Moreover, physical interaction between ROCK II and NPM/B23 in vivo occurs in association with CDK2/cyclin E activation and the emergence of Thr(199)-phosphorylated NPM/B23. All these findings point to ROCK II as the effector of the CDK2/cyclin E-NPM/B23 pathway in the regulation of centrosome duplication.

Centrosome amplification in adult T-cell leukemia and human T-cell leukemia virus type 1 Tax-induced human T cells.

Centrosomes play pivotal roles in cell polarity, regulation of the cell cycle and chromosomal segregation. Centrosome amplification was recently described as a possible cause of aneuploidy in certain solid tumors and leukemias. ATL is a T-cell malignancy caused by HTLV-1. Although the precise mechanism of cell transformation is unclear, the HTLV-1-encoded protein, Tax, is thought to play a crucial role in leukemogenesis. Here we demonstrate that lymphocytes isolated from patients with ATL show centrosome amplification and that a human T cell line shows centrosome amplification after induction of Tax, which was suppressed by CDK inhibitors. Micronuclei formation was also observed after centrosome amplification in Tax-induced human T cells. These findings suggest that Tax deregulates CDK activity and induces centrosome amplification, which might be associated with cellular transformation by HTLV-1 and chromosomal instability in HTLV-1-infected human T cells.

Suppression of centrosome amplification after DNA damage depends on p27 accumulation.

The centrosome plays a fundamental role in cell division, cell polarity, and cell cycle progression. Centrosome duplication is mainly controlled by cyclin-dependent kinase 2 (CDK2)/cyclin E and cyclin A complexes, which are inhibited by the CDK inhibitors p21Cip1 and p27Kip1. It is thought that abnormal activation of CDK2 induces centrosome amplification that is frequently observed in a wide range of aggressive tumors. We previously reported that overexpression of the oncogene MYCN leads to centrosome amplification after DNA damage in neuroblastoma cells. We here show that centrosome amplification after gamma-irradiation was caused by suppression of p27 expression in MYCN-overexpressing cells. We further show that p27-/- and p27+/- mouse embryonic fibroblasts and p27-silenced human cells exhibited a significant increase in centrosome amplification after DNA damage. Moreover, abnormal mitotic cells with amplified centrosomes were frequently observed in p27-silenced cells. In response to DNA damage, the level of p27 gradually increased in normal cells independently of the ataxia telangiectasia mutated/p53 pathway, whereas Skp2, an F-box protein component of an SCF ubiquitin ligase complex that targets p27, was reduced. Additionally, p27 levels in MYCN-overexpressing cells were restored by treatment with Skp2 small interfering RNA, indicating that down-regulation of p27 by MYCN was due to high expression of Skp2. These results suggest that the accumulation of p27 after DNA damage is required for suppression of centrosome amplification, thereby preventing chromosomal instability.

Loss of poly(ADP-ribose) glycohydrolase causes progressive neurodegeneration in Drosophila melanogaster.

Poly(ADP-ribosyl)ation has been suggested to be involved in regulation of DNA repair, transcription, centrosome duplication, and chromosome stability. However, the regulation of degradation of poly(ADP-ribose) and its significance are not well understood. Here we report a loss-of-function mutant Drosophila with regard to poly(ADP-ribose) glycohydrolase, a major hydrolyzing enzyme of poly(ADP-ribose). The mutant lacks the conserved catalytic domain of poly(ADP-ribose) glycohydrolase, and exhibits lethality in the larval stages at the normal development temperature of 25 degrees C. However, one-fourth of the mutants progress to the adult stage at 29 degrees C but showed progressive neurodegeneration with reduced locomotor activity and a short lifespan. In association with this, extensive accumulation of poly(ADP-ribose) could be detected in the central nervous system. These results suggest that poly(ADP-ribose) metabolism is required for maintenance of the normal function of neuronal cells. The phenotypes observed in the parg mutant might be useful to understand neurodegenerative conditions such as the Alzheimer's and Parkinson's diseases that are caused by abnormal accumulation of substances in nervous tissue.

Enhanced expression of MYCN leads to centrosome hyperamplification after DNA damage in neuroblastoma cells.

Centrosomes play important roles in cell polarity, regulation of cell cycle and chromosomal stability. Centrosome abnormality is frequently found in many cancers and contributes to chromosomal instability (including aneuploidy, tetraploidy, and/or micronuclei) in daughter cells through the assembly of multipolar or monopolar spindles during mitosis. It has recently been reported that loss of tumor suppressor genes or overexpression of oncogenes causes centrosome hyperamplification. Amplification and overexpression of the MYCN oncogene is found in a subgroup of neuroblastomas. In this study, we examined whether overexpression of MYCN causes centrosome hyperamplification in neuroblastoma cells. We show that ectopic expression of MYCN alone in a neuroblastoma cell line did not cause centrosome hyperamplification. However, centrosome hyperamplification and micronuclei formation were seen in these cells after DNA damage. These findings suggest that overexpression of MYCN abrogates the regulation of the centrosome cycle after DNA damage.

Subcellular localization of poly(ADP-ribose) glycohydrolase in mammalian cells.

Posttranslational modification plays important roles in a range of cellular functions. Poly(ADP-ribosyl)ation influences DNA repair, transcription, centrosome duplication, and chromosome stability. Poly(ADP-ribose) attached to acceptor proteins should be properly hydrolyzed by poly(ADP-ribose) glycohydrolase (PARG). However the subcellular localization and the role of PARG have not been well characterized. Here, we transiently expressed GFP- or Myc-tagged human PARG in mammalian cells and revealed that the subcellular distribution of human PARG changes dramatically during the cell cycle. GFP-hPARG is found almost exclusively in the nucleus during interphase. During mitosis, most GFP-hPARG protein localizes to the cytoplasm and hardly any GFP-hPARG protein is found associated with the chromosomes. Furthermore, we found that GFP-hPARG localizes to the centrosomes during mitosis. Our findings suggest that shuttling of PARG between nucleus and cytoplasm and proper control of poly(ADP-ribose) metabolism throughout the cell cycle may play an important role in regulating cell cycle progression and centrosome duplication.

Involvement of poly(ADP-Ribose) polymerase 1 and poly(ADP-Ribosyl)ation in regulation of centrosome function.

The regulatory mechanism of centrosome function is crucial to the accurate transmission of chromosomes to the daughter cells in mitosis. Recent findings on the posttranslational modifications of many centrosomal proteins led us to speculate that these modifications might be involved in centrosome behavior. Poly(ADP-ribose) polymerase 1 (PARP-1) catalyzes poly(ADP-ribosyl)ation to various proteins. We show here that PARP-1 localizes to centrosomes and catalyzes poly(ADP-ribosyl)ation of centrosomal proteins. Moreover, centrosome hyperamplification is frequently observed with PARP inhibitor, as well as in PARP-1-null cells. Thus, it is possible that chromosomal instability known in PARP-1-null cells can be attributed to the centrosomal dysfunction. P53 tumor suppressor protein has been also shown to be localized at centrosomes and to be involved in the regulation of centrosome duplication and monitoring of the chromosomal stability. We found that centrosomal p53 is poly(ADP-ribosyl)ated in vivo and centrosomal PARP-1 directly catalyzes poly(ADP-ribosyl)ation of p53 in vitro. These results indicate that PARP-1 and PARP-1-mediated poly(ADP-ribosyl)ation of centrosomal proteins are involved in the regulation of centrosome function.

[Met5]enkephalin-Arg-Gly-Leu-induced antinociception is greatly increased by peptidase inhibitors.

Previous in vitro studies showed that the degradation of [Met(5)]enkephalin-Arg-Gly-Leu by cerebral membrane preparations is almost completely prevented by a mixture of three peptidase inhibitors: amastatin, captopril and phosphoramidon. The present investigations showed that the inhibitory effect of [Met(5)]enkephalin-Arg-Gly-Leu administered intra-third-ventricularly on the tail-flick response was increased more than 1000-fold by the intra-third-ventricular pretreatment of rats with three peptidase inhibitors. The inhibition produced by the enkephalin octapeptide in rats pretreated with any combination of two peptidase inhibitors was significantly smaller than that in rats pretreated with three peptidase inhibitors, indicating that any residual single peptidase could inactivate significant amounts of the octapeptide. The present data, together with those obtained from previous studies, clearly show that three types of enzymes, amastatin-, captopril- and phosphoramidon-sensitive enzymes, play important roles in the inactivation of endogenous opioid penta- and octa-peptides administered intra-third-ventricularly to rats.