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1.
Clin Case Rep ; 12(5): e8738, 2024 May.
Article in English | MEDLINE | ID: mdl-38681045

ABSTRACT

Cardiomyopathy is a rare but serious complication associated with neuroblastoma. The brain natriuretic peptide level led to a diagnosis of secondary dilated cardiomyopathy before the worsening of heart failure symptoms.

3.
Exp Clin Transplant ; 19(11): 1228-1231, 2021 11.
Article in English | MEDLINE | ID: mdl-34812712

ABSTRACT

Immunothrombocytopenic purpura is a possible complication after liver transplant. The therapy for immunothrombocytopenic purpura after liver transplant is similar to that of primary immunothrombocytopenic purpura. This therapy consists of corticosteroids, intravenous immunoglobulin, and immunosuppressive agents such as cyclosporine and rituximab. There are a few cases of immunothrombocytopenic purpura in patients who recovered after cessation of tacrolimus administration. Here, we show an intractable case of immunothrombocytopenic purpura in a living related liver transplant recipient treated with some of these. We observed complete remission after switch ofthe immunosuppressive agent from tacrolimus to cyclosporine. The patient was an infant girl aged 18 months who underwent livingr elated liver transplant for biliary atresia when she was 6 months old. Liver graft was a left lateral segment from her father. Purpura and severe thrombocytopenia developed after 11 months.There was no effect of the first-line therapies, as described in the Japan guidelines for immunothrombocytopenic purpura.Thrombocytopenia was extreme, as shown by a blood count of 0 platelets/µL. Administration of rituximab was started. However, her platelet count had not increased 8 weeks after rituximab initiation. As a trial therapy, we switched tacrolimus to cyclosporine. She showed complete remission 1 month after this drug conversion. Thus, a switch from tacrolimus to other immunosuppressive agents as a therapy for immunothrombocytopenic purpura after living related liver transplant should be considered.


Subject(s)
Immunosuppressive Agents , Purpura , Thrombocytopenia , Cyclosporine/therapeutic use , Female , Humans , Immunosuppressive Agents/therapeutic use , Infant , Liver Transplantation/adverse effects , Purpura/drug therapy , Rituximab/therapeutic use , Tacrolimus/therapeutic use , Thrombocytopenia/drug therapy , Treatment Outcome
4.
Clin Case Rep ; 8(11): 2314-2315, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33235790

ABSTRACT

Clinicians need to consider hepatoblastoma in the differential even in school-aged children or adolescents presenting with multiple liver tumors.

6.
Pediatr Transplant ; 21(7)2017 Nov.
Article in English | MEDLINE | ID: mdl-28834141

ABSTRACT

Acute GVHD is a rare complication after liver transplantation that has a high mortality rate. We experienced an infant case complicated with acute GVHD. An 8-month-old infant with biliary atresia underwent LDLT with a graft obtained from his mother. Their HLAs showed a donor-dominant one-way match, not at HLA-DR but at HLA-A, HLA-B, and HLA-C (recipient; A 31/33, B 51/54, C 1/14, DR 9/11, donor; A 31/-, B 51/-, C 14/-, DR 8/11). The patient exhibited a high fever, skin rash, and diarrhea, and was diagnosed with acute GVHD based on the blood chimerism test. Despite immunosuppression treatment with prednisolone and tacrolimus, plasma exchange, blood transfusion including cord blood transplantation, and antibiotics, the child died on postoperative day 126. Donor-dominant one-way matching at HLA class 1 can be a high-risk factor for acute GVHD despite HLA class 2 mismatching.


Subject(s)
Graft vs Host Disease/immunology , HLA-DR Antigens/immunology , Histocompatibility , Liver Transplantation , Living Donors , Fatal Outcome , Humans , Infant , Male
7.
Anticancer Res ; 36(5): 2505-11, 2016 May.
Article in English | MEDLINE | ID: mdl-27127165

ABSTRACT

AIM: This prospective study was designed to evaluate the tolerability and the efficacy of bi-weekly SOX (S-1 and oxaliplatin)+cetuximab as first-line chemotherapy for wild-type K-RAS metastatic colorectal cancer. PATIENTS AND METHODS: We studied patients with previously untreated, unresectable, advanced or recurrent colorectal cancer who were treated in our hospital between October 2010 and March 2013. Their performance status (PS) was 0 to 1. Cetuximab was combined with S-1 and oxaliplatin (SOX+cetuximab). S-1 was given orally at a dose of 40 mg/m(2) (40-60 mg, calculated according to body surface area) twice daily after meals for 2 weeks, followed by a 2-week rest (course 1). Oxaliplatin (85 mg/m(2)) was given on days 1 and 15 of each course. Cetuximab was administered on days 1 (400 mg/m(2)), 8 (250 mg/m(2)) and 15 (500 mg/m(2)) of course 1, followed by every 2 weeks (500 mg/m(2)) thereafter. RESULTS: The study group comprised of 18 patients. The mean age was 61 (range=32-72) years, the male:female ratio was 10:8 and the PS was 0 in 12 patients and 1 in 6 patients. The median number of administered courses was 6 (range=2-12). The treatment response was complete response (CR) in 2 and partial response (PR) in 10 (response rate=67% (12/18 patients)). The minimum number of treatment courses until a PR was 2, indicating an early response. Liver resection was performed in 4 patients (22.2%). The incidence of any adverse events (Grade 3/4) was 28% (5/18), including skin disorder (16.7%) as dry skin, cutaneous pruritus, contusion and paronychia, as well as peripheral sensory neuropathy (11.1%). The any-grade events of skin disorders and peripheral sensory neuropathy were mostly observed in all patients. These events were controllable by preventive skin care and by withdrawal and dose reduction, respectively. Death due to adverse events was not observed. Adverse events did not require the withdrawal of this regimen. CONCLUSION: Based on the 18 patients studied, combined therapy with SOX+cetuximab was free of serious adverse events and could be safely administered by reducing the dose or temporarily suspending treatment, as required. These regimens seem to be promising for conversion therapy (4 out of 18 patients) because of good outcomes and an early response.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Colorectal Neoplasms/drug therapy , Genes, ras , Adult , Aged , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Cetuximab/administration & dosage , Colorectal Neoplasms/pathology , Drug Combinations , Female , Humans , Male , Middle Aged , Organoplatinum Compounds/administration & dosage , Oxaliplatin , Oxonic Acid/administration & dosage , Prospective Studies , Recurrence , Tegafur/administration & dosage
8.
Surg Laparosc Endosc Percutan Tech ; 25(1): e37-e41, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25635674

ABSTRACT

INTRODUCTION: Advances in energy devices have played a major role in the rapid expansion of laparoscopic surgery. However, complications due to these energy devices are occasionally reported, and if the characteristics of these devices are not well understood, serious complications may occur. This study evaluated various typical energy devices and measured temperature rises in the adjacent tissue and in the devices themselves. EQUIPMENT AND METHODS: We used the following 7 types of energy devices: AutoSonix (AU), SonoSurg (SS), Harmonic Scalpel (HS), LigaSure Atlas (LA), LigaSure Dolphin Tip (LD), monopolar diathermy (Mono), and bipolar scissors (Bi). Laparoscopy was performed under general anesthesia in pigs, and the mesentery was dissected using each energy device. Tissue temperature at a distance of 1 mm from the energy device blade before and after dissection was measured. Temperature of the device blade both before and after dissection, time required for dissection, and interval until the temperature fell to 100°C, 75°C, and 50°C were documented. RESULTS: Temperature of the surrounding tissue using each device rose the most with the Mono (50.5±8.0°C) and the least with the HS in full mode (6.2±0.7°C). Device temperature itself rose the highest with the AU in full mode (318.2±49.6°C), and the least with the Bi (61.9±4.8°C). All ultrasonic coagulation and cutting devices (AU, SS, and HS) had device temperatures increase up to ≥100°C, and even at 8 seconds after completing dissection, temperatures remained at ≥100°C. CONCLUSIONS: Because the adjacent tissue temperature peaked with the Mono, cautious use near the intestine and blood vessels is necessary. In addition, the active blades of all ultrasonic coagulation and cutting devices, regardless of model, developed high temperatures exceeding 100°C. Therefore, an adequate cooling period after using these devices is therefore necessary between applications.


Subject(s)
Body Temperature/radiation effects , Electrocoagulation/instrumentation , Electrosurgery/instrumentation , Laparoscopy/instrumentation , Mesentery/radiation effects , Ultrasonic Surgical Procedures/instrumentation , Animals , Dissection/instrumentation , Mesentery/surgery , Swine , Temperature
9.
Oncol Lett ; 8(6): 2463-2468, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25364408

ABSTRACT

The aim of the present study was to investigate markers in surgically resected specimens of colorectal cancer that can be used to predict the response to chemotherapy. The mRNA expression levels of enzymes involved in 5-fluorouracil (5-FU) metabolism and folate metabolism were measured in formalin-fixed, paraffin-embedded tumor sections obtained from the primary tumors of 54 patients with resected stage II or III colorectal cancer who received S-1 for one year. The 5-FU metabolizing enzymes studied were thymidylate synthase, dihydropyrimidine dehydrogenase and thymidine phosphorylase (TP). The folate metabolizing enzymes studied were folypolyglutamate synthetase, γ-glutamyl hydrolase and dihydrofolate reductase. The associations between the mRNA expression levels of these enzymes and clinical variables were investigated. Tumors were classified as exhibiting high or low expression as compared with the median mRNA expression level of each metabolizing enzyme defined as the cutoff value. The associations between the high and low expression levels of each enzyme and disease-free survival (DFS) were analyzed with the use of Kaplan-Meier curves and the log-rank test. DFS was not significantly associated with the relative mRNA expression level of any metabolizing enzyme in the study group as a whole, but there was a trend toward longer DFS in patients with high TP expression (P=0.066). In patients with stage III colorectal cancer, high TP expression was associated with significantly improved outcomes compared with low TP expression (P=0.039). These results indicate that the mRNA expression of TP, a metabolizing enzyme of 5-FU, is a significant predictor of response to post-operative chemotherapy with S-1 in patients with stage III colorectal cancer.

10.
J Biol Chem ; 289(26): 18137-51, 2014 Jun 27.
Article in English | MEDLINE | ID: mdl-24831002

ABSTRACT

α-Synuclein (aS) is a major constituent of Lewy bodies, which are not only a pathological marker for Parkinson disease but also a trigger for neurodegeneration. Cumulative evidence suggests that aS spreads from cell to cell and thereby propagates neurodegeneration to neighboring cells. Recently, Nedd4-1 (neural precursor cell expressed developmentally down-regulated protein 4-1), an E3 ubiquitin ligase, was shown to catalyze the Lys-63-linked polyubiquitination of intracellular aS and thereby facilitate aS degradation by the endolysosomal pathway. Because Nedd4-1 exerts its activity in close proximity to the inner leaflet of the plasma membrane, we speculate that after the internalization of aS the membrane resident aS is preferentially ubiquitinated by Nedd4-1. To clarify the role of Nedd4-1 in aS internalization and endolysosomal sequestration, we generated aS mutants, including ΔPR1(1-119 and 129-140), ΔC(1-119), and ΔPR2(1-119 and 134-140), that lack the proline-rich sequence, a putative Nedd4-1 recognition site. We show that wild type aS, but not ΔPR1, ΔPR2, or ΔC aS, is modified by Nedd4-1 in vitro, acquiring a Lys-63-linked ubiquitin chain. Compared with the mutants lacking the proline-rich sequence, wild type-aS is preferentially internalized and translocated to endosomes. The overexpression of Nedd4-1 increased aS in endosomes, whereas RNAi-mediated silencing of Nedd4-1 decreased endosomal aS. Although aS freely passes through plasma membranes within minutes, a pulse-chase experiment revealed that the overexpression of Nedd4-1 markedly decreased the re-secretion of internalized aS. Together, these findings demonstrate that Nedd4-1-linked Lys-63 ubiquitination specifies the fate of extrinsic and de novo synthesized aS by facilitating their targeting to endosomes.


Subject(s)
Endosomal Sorting Complexes Required for Transport/metabolism , Endosomes/metabolism , Lysine/metabolism , Ubiquitin-Protein Ligases/metabolism , alpha-Synuclein/chemistry , alpha-Synuclein/metabolism , Amino Acid Motifs , Cell Line, Tumor , Endosomal Sorting Complexes Required for Transport/genetics , Endosomes/genetics , Humans , Lysine/genetics , Nedd4 Ubiquitin Protein Ligases , Parkinson Disease/genetics , Parkinson Disease/metabolism , Protein Transport , Ubiquitin-Protein Ligases/genetics , Ubiquitination , alpha-Synuclein/genetics
11.
Anticancer Res ; 33(11): 5011-5, 2013 Nov.
Article in English | MEDLINE | ID: mdl-24222144

ABSTRACT

BACKGROUND: The use of a protective defunctioning stoma in rectal cancer surgery has been reported to reduce the rates of reoperation for anastomotic leakage, as well as mortality after surgery. However, a protective defunctioning stoma is not often used in cases other than low rectal cancer because of the need for stoma closure later, and hesitation by patients to have a stoma. We outline a novel and patient-friendly procedure with an excellent cosmetic outcome. This procedure uses the umbilical fossa for placement of a defunctioning ileostomy followed by a simple umbilicoplasty for ileostomy closure. PATIENTS AND METHODS: This study included a total of 20 patients with low rectal cancer who underwent a laparoscopic low anterior resection with defunctioning ileostomy (10 cases with a conventional ileostomy in the right iliac fossa before March 2012, and 10 subsequent cases with ileostomy at the umbilicus) at the Jikei University Hospital in Tokyo from August 2011 to January 2013. The clinical characteristics of the two groups were compared: operative time, blood loss, length of hospital stay and postoperative complications of the initial surgery, as well as the stoma closure procedure. RESULTS: There were no differences between the groups in the median operative time for initial surgery (248 min vs. 344 min), median blood loss during initial surgery (0 ml vs. 115 ml), and median hospital stay after initial surgery (13 days vs. 16 days). Complication rates after the initial surgery were similar. There were no differences between the groups in median operative time for stoma closure (99 min vs. 102 min), median blood loss during stoma closure (7.5 ml vs. 10 ml), and median hospital stay after stoma closure (8 days in both groups). Complications after stoma closure such as wound infection and intestinal obstruction were comparable. Thus, no significant differences in any factor were found between the two groups. CONCLUSION: The transumbilical protective defunctioning stoma is a novel solution to anastomotic leakage after laparoscopic rectal cancer surgery, with patient-friendliness as compared to conventional procedures in light of the cosmetic outcome.


Subject(s)
Anastomosis, Surgical/adverse effects , Anastomotic Leak/prevention & control , Ileostomy , Laparoscopy/adverse effects , Rectal Neoplasms/surgery , Surgical Stomas , Adult , Aged , Anastomotic Leak/etiology , Female , Follow-Up Studies , Humans , Length of Stay , Male , Middle Aged , Neoplasm Staging , Postoperative Complications , Prognosis , Rectal Neoplasms/complications , Reoperation , Survival Rate
12.
Int J Clin Oncol ; 18(4): 678-83, 2013 Aug.
Article in English | MEDLINE | ID: mdl-22585427

ABSTRACT

BACKGROUND: We evaluated the safety, efficacy, and compliance of 1-year treatment with S-1 in patients with stage II/III resectable colorectal cancer. METHODS: S-1 was administered orally in two divided doses daily. The dose was assigned according to body surface area (BSA) as follows: BSA <1.25 m(2), 80 mg/day; BSA ≥1.25 to <1.5 m(2), 100 mg/day; and BSA ≥1.5 m(2), 120 mg/day. S-1 was given for 28 consecutive days, followed by a 14-day rest. The study objects were the rate of completion of treatment as planned at 1 year, the ratio of the actually administered dose to the planned dose at 1 year, and the total number of days of treatment. RESULTS: At 1 year, the rate of completion of treatment as planned was 77.7 % (42/54 patients), and the ratio of the actually administered dose to the planned dose was 82.9 %. The mean and median total numbers of days of treatment were 209 and 252, respectively. Grade 3 or higher toxicity (watery eyes) occurred in only 1 patient. CONCLUSION: S-1 adjuvant chemotherapy had acceptable compliance, safety, and efficacy in patients with colorectal cancer. S-1 adjuvant chemotherapy is considered a possible standard treatment regimen for colorectal cancer.


Subject(s)
Colorectal Neoplasms/drug therapy , Oxonic Acid/therapeutic use , Tegafur/therapeutic use , Adult , Aged , Aged, 80 and over , Antimetabolites, Antineoplastic/administration & dosage , Antimetabolites, Antineoplastic/therapeutic use , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Chemotherapy, Adjuvant/methods , Colorectal Neoplasms/mortality , Colorectal Neoplasms/surgery , Disease-Free Survival , Drug Administration Schedule , Drug Combinations , Feasibility Studies , Female , Humans , Male , Middle Aged , Oxonic Acid/administration & dosage , Oxonic Acid/adverse effects , Tegafur/administration & dosage , Tegafur/adverse effects , Treatment Outcome
13.
Pediatr Surg Int ; 28(1): 59-62, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22009205

ABSTRACT

A girl presented with a right adrenal mass, and multiple hepatic lesions and subcutaneous nodules 3 months after complete resection of left adrenal neuroblastoma in the neonatal period. She was treated with six cycles of chemotherapy and is well after 13 months' follow-up. This is the first case report of heterochronous bilateral adrenal stage 4S NB.


Subject(s)
Adrenal Gland Neoplasms/diagnosis , Adrenal Glands/pathology , Adrenalectomy , Neoplasm Staging , Neuroblastoma/diagnosis , Adrenal Gland Neoplasms/surgery , Adrenal Glands/diagnostic imaging , Diagnosis, Differential , Female , Follow-Up Studies , Humans , Infant, Newborn , Neuroblastoma/surgery , Time Factors , Tomography, X-Ray Computed , Ultrasonography
14.
Pediatr Blood Cancer ; 56(1): 110-5, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21108445

ABSTRACT

BACKGROUND: Several studies have suggested that Langerhans cell histiocytosis (LCH) is responsive to treatment with bisphosphonates (BPs). However the efficacy and safety of BPs therapy for childhood LCH is unknown. PROCEDURE: Data on children with LCH who had received BPs therapy were collected retrospectively from hospitals participating in the Japanese Pediatric Leukemia/Lymphoma Study Group. RESULTS: Twenty-one children with histologically proven LCH were identified. Of these, the case histories of 16 children who had been treated with pamidronate (PAM) for disease reactivation were analyzed in detail. The median post-PAM therapy follow-up period was 2.8 years (range: 0.9-9.3 years). The median age at commencement of PAM therapy was 9.4 years (range: 2.3-15.0 years). All children had one or more bone lesions but none had risk organ (RO) involvement. In the majority of the children, six courses of PAM were administered at a dose of 1.0 mg/kg/course at 4-week intervals. In 12 of the 16 children, all active lesions including lesions of the skin (n = 3) and soft tissues (n = 3) resolved. Of these children, eight children had no active disease for a median of 3.3 years post-PAM therapy (range: 1.8-9.3 years). Progression-free survival (PFS) was 56.3 ± 12.4% at 3 years. PFS was significantly higher in children with a first reactivation compared with children experiencing a second or subsequent reactivation. CONCLUSIONS: PAM may be an effective treatment for reactivated LCH with bone lesions. A prospective trial of the efficacy of PAM in recurrent pediatric LCH is warranted.


Subject(s)
Diphosphonates/therapeutic use , Histiocytosis, Langerhans-Cell/drug therapy , Adolescent , Child , Child, Preschool , Disease-Free Survival , Drug Evaluation , Drug-Related Side Effects and Adverse Reactions , Female , Histiocytosis, Langerhans-Cell/complications , Histiocytosis, Langerhans-Cell/pathology , Humans , Japan , Male , Pamidronate , Recurrence , Retrospective Studies , Treatment Outcome
15.
J Pediatr Surg ; 44(2): e33-8, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19231519

ABSTRACT

We present the cases of 3 children with huge undifferentiated sarcoma of the liver who were treated with surgical excision including liver transplantation as an option and adjuvant chemotherapy. All 3 patients were males aged 10, 13, and 15 years old. The size of the tumor was 10, 15, and 20 cm in diameter, respectively. The youngest patient is disease free and doing well 43 months after resection. The 13-year-old patient presented with tumor rupture and underwent operation. The primary tumor and the ruptured tissue fragments were removed and he was given postoperative chemotherapy. The patient is disease free and doing well 52 months after surgery. The oldest patient had an unresectable tumor in the hilar region. Preoperative chemotherapy was given but later discontinued owing to severe side effects. He underwent living donor liver transplantation followed by postoperative chemotherapy. The patient had recurrent tumor 24 months after transplantation that was excised at reoperation. He is doing well and is disease free 18 months after the second procedure. Complete removal of the tumor including total hepatectomy and transplantation when indicated and suitable pre- and/or postoperative chemotherapy is an effective treatment for children with undifferentiated sarcoma of the liver.


Subject(s)
Liver Neoplasms/surgery , Liver Transplantation , Sarcoma/surgery , Adolescent , Child , Humans , Living Donors , Male
16.
Int J Surg ; 6(3): 234-7, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18555758

ABSTRACT

We investigated the necessity of preparation for blood transfusion in gastric cancer surgery to save costs for blood typing, antibody screening, cross-matching, and disposal of the blood product. The subjects of the study were 52 patients who underwent gastric cancer surgery at our department between 2000 and 2004. The requirement for blood transfusion during surgery was investigated in terms of patient characteristics, hemoglobin before surgery, and performance status as well as treatment regimen. Furthermore, economic effects were investigated when typing and screening (T&S) were performed instead of typing and cross-matching (T&X). Of 9 patients who received blood transfusion, 8 had gastric cancer of stage IIIB or higher, or underwent combined resection. Blood transfusion was not used in surgery for patients with early gastric cancer. The volumes of blood prepared, lost, and disposed of in 28 patients who underwent T&X were 831.3+/-249.4, 219.3+/-228.5 and 600+/-333.1 ml, respectively, whereas the blood loss in 24 patients who underwent T&S was 161.1+/-95.6 ml; this difference had a major economic effect. The practice of T&S for patients undergoing gastric surgery in the absence of combined resection for early gastric cancer seems to be a safe and cost-effective practice that abrogates disposal of blood in hospital management.


Subject(s)
Blood Grouping and Crossmatching , Blood Transfusion , Stomach Neoplasms/surgery , Aged , Blood Grouping and Crossmatching/economics , Blood Loss, Surgical , Female , Gastrectomy , Humans , Japan , Male , National Health Programs , Stomach Neoplasms/pathology
17.
J Cell Biol ; 174(7): 939-49, 2006 Sep 25.
Article in English | MEDLINE | ID: mdl-17000875

ABSTRACT

Small ubiquitin-related modifier (SUMO) processing and deconjugation are mediated by sentrin-specific proteases/ubiquitin-like proteases (SENP/Ulps). We show that SUMO-specific protease 1 (SUSP1), a mammalian SENP/Ulp, localizes within the nucleoplasm. SUSP1 depletion within cell lines expressing enhanced green fluorescent protein (EGFP) fusions to individual SUMO paralogues caused redistribution of EGFP-SUMO2 and -SUMO3, particularly into promyelocytic leukemia (PML) bodies. Further analysis suggested that this change resulted primarily from a deficit of SUMO2/3-deconjugation activity. Under these circumstances, PML bodies became enlarged and increased in number. We did not observe a comparable redistribution of EGFP-SUMO1. We have investigated the specificity of SUSP1 using vinyl sulfone inhibitors and model substrates. We found that SUSP1 has a strong paralogue bias toward SUMO2/3 and that it acts preferentially on substrates containing three or more SUMO2/3 moieties. Together, our findings argue that SUSP1 may play a specialized role in dismantling highly conjugated SUMO2 and -3 species that is critical for PML body maintenance.


Subject(s)
Cysteine Endopeptidases/physiology , Small Ubiquitin-Related Modifier Proteins/antagonists & inhibitors , Ubiquitins/antagonists & inhibitors , Cell Line, Tumor , Cysteine Endopeptidases/analysis , Cysteine Endopeptidases/pharmacology , Endopeptidases/classification , HeLa Cells , Humans , Multiprotein Complexes/analysis , Multiprotein Complexes/antagonists & inhibitors , Multiprotein Complexes/metabolism , Neoplasm Proteins/chemistry , Neoplasm Proteins/metabolism , Nuclear Proteins/chemistry , Nuclear Proteins/metabolism , Phylogeny , Promyelocytic Leukemia Protein , Small Ubiquitin-Related Modifier Proteins/analysis , Small Ubiquitin-Related Modifier Proteins/metabolism , Substrate Specificity , Transcription Factors/chemistry , Transcription Factors/metabolism , Tumor Suppressor Proteins/chemistry , Tumor Suppressor Proteins/metabolism , Ubiquitins/analysis , Ubiquitins/metabolism
18.
EMBO J ; 24(12): 2172-82, 2005 Jun 15.
Article in English | MEDLINE | ID: mdl-15933717

ABSTRACT

Here we show that the PIASy protein is specifically required for mitotic modification of Topoisomerase-II by SUMO-2 conjugation in Xenopus egg extracts. PIASy was unique among the PIAS family members in its capacity to bind mitotic chromosomes and recruit Ubc9 onto chromatin. These properties were essential, since PIASy mutants that did not bind chromatin or failed to recruit Ubc9 were functionally inactive. We observed that PIASy depletion eliminated essentially all chromosomal accumulation of EGFP-SUMO-2-conjugated species, suggesting that it is the primary E3-like factor for mitotic chromosomal substrates of SUMO-2. PIASy-dependent SUMO-2-conjugated species were highly concentrated on the inner centromere, and inhibition of PIASy blocked anaphase sister chromatid segregation in egg extracts. Taken together, our observations suggest that PIASy is a critical regulator of mitotic SUMO-2 conjugation for Topoisomerase-II and other chromosomal substrates, and that its activity may have particular relevance for centromeric functions required for proper chromosome segregation.


Subject(s)
Chromosomes/physiology , DNA Topoisomerases, Type II/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Mitosis/physiology , Small Ubiquitin-Related Modifier Proteins/metabolism , Animals , Chromatin/metabolism , Chromosome Segregation/physiology , Humans , Poly-ADP-Ribose Binding Proteins , Protein Binding , Protein Inhibitors of Activated STAT , Protein Structure, Tertiary , Spindle Apparatus/metabolism , Ubiquitin-Conjugating Enzymes/metabolism , Xenopus
19.
J Biol Chem ; 277(5): 3599-605, 2002 Feb 01.
Article in English | MEDLINE | ID: mdl-11714696

ABSTRACT

Ubiquitin ligases define the substrate specificity of protein ubiquitination and subsequent proteosomal degradation. The catalytic sequence was first characterized in the C terminus of E6-associated protein (E6AP) and referred to as the HECT (homologous to E6AP C terminus) domain. The human homologue of the regulator of cell proliferation hyperplastic discs in Drosophila, designated hHYD, is a HECT-domain ubiquitin ligase. Here we show that hHYD provides a ubiquitin system for a cellular response to DNA damage. A yeast two-hybrid screen showed that DNA topoisomerase IIbeta-binding protein 1 (TopBP1) interacted with hHYD. Endogenous hHYD bound the BRCA1 C-terminus domains of TopBP1 that are highlighted in DNA damage checkpoint proteins and cell cycle regulators. Using an in vitro reconstitution, specific E2 (ubiquitin-conjugating) enzymes (human UbcH4, UbcH5B, and UbcH5C) transferred ubiquitin molecules to hHYD, leading to the ubiquitination of TopBP1. TopBP1 was usually ubiquitinated and degraded by the proteosome, whereas X-irradiation diminished the ubiquitination of TopBP1 probably via the phosphorylation, resulting in the stable colocalization of up-regulated TopBP1 with gamma-H2AX nuclear foci in DNA breaks. These results demonstrated that hHYD coordinated TopBP1 in the DNA damage response.


Subject(s)
Carrier Proteins/chemistry , Carrier Proteins/metabolism , DNA Damage , Peptide Synthases/chemistry , Peptide Synthases/metabolism , Ubiquitin-Protein Ligases , Ubiquitin/metabolism , Animals , COS Cells , Catalytic Domain , Chlorocebus aethiops , DNA-Binding Proteins , Dithiothreitol/pharmacology , Gene Library , HeLa Cells , Humans , Molecular Sequence Data , Muscle, Skeletal/enzymology , Nuclear Proteins , Phosphorylation/radiation effects , Saccharomyces cerevisiae/enzymology , Signal Transduction , Substrate Specificity , Transfection , X-Rays
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