Application of polyglycolic acid sheets and basic fibroblast growth factor to prevent esophageal stricture after endoscopic submucosal dissection in pigs.

BACKGROUND: Endoscopic submucosal dissection (ESD) has been the first-line treatment for early-stage esophageal cancer. However, it often causes postoperative stricture in cases requiring wide dissection. Basic fibroblast growth factor (bFGF) reportedly has anti-scarring effects during cutaneous wound healing. We hypothesized that suppressing myofibroblast activation will prevent stricture after esophageal ESD. METHODS: We resected a complete porcine esophagus circumference section by ESD. To investigate the preventive effect of bFGF on esophageal stricture formation after ESD, we endoscopically applied bFGF-soaked poly-glycolic acid (PGA) sheets onto the wound bed after ESD and fixed them by spraying fibrin glue (PGA + bFGF group), PGA sheets alone onto the wound bed and fixed them by spraying fibrin glue (PGA group), or nothing (control group). After removing the esophagus on day 22, we evaluated the mucosal constriction rate. RESULTS: Compared with those in the control group, esophageal stricture was significantly reduced in the PGA + bFGF group, and the areas stained with α-SMA and calponin-1 antibodies were significantly inhibited in the PGA + bFGF and PGA groups. The thickness of the fibrous layer in the PGA + bFGF group was uniform compared to that of the other groups. Thus, PGA + bFGF inhibited the development of unregulated fibroblasts in the acute phase, leading to uniform wound healing. CONCLUSIONS: Stenosis after esophageal ESD is related to fibrosis in the acute phase. Administration of PGA and bFGF suppresses myofibroblast activation in the acute phase, thereby preventing esophageal constriction in pigs.

Incidence of cancer-associated thromboembolism in Japanese gastric and colorectal cancer patients receiving chemotherapy: a single-institutional retrospective cohort analysis (Sapporo CAT study).

OBJECTIVE: Few data regarding the incidence of cancer-associated thromboembolism (TE) are available for Asian populations. We investigated the incidence of TE (TEi) and its risk factors among gastric and colorectal cancer (GCC) patients received chemotherapy in a daily practice setting. DESIGN: A retrospective cohort study. SETTING: A single-institutional study that used data from Sapporo City General Hospital, Japan, on patients treated between January 2008 and May 2015. PARTICIPANTS: Five hundred Japanese GCC patients who started chemotherapy from January 2008 to May 2015. PRIMARY AND SECONDARY OUTCOME MEASURES: TE was diagnosed by reviewing all the reports of contrast-enhanced CT performed during the follow-up period. All types of thrombosis detected by CT or additional imaging tests, such as venous TE, arterial TE and cerebral infarction, were defined as TE. Medical records of all identified patients were reviewed and potential risk factors for TE, including clinicopathological backgrounds, were collected. We defined the following patients as 'active cancer'; patients with unresectable advanced GCC, cancer recurrence during or after completing adjuvant chemotherapy and/or presence of other malignant tumours. RESULTS: Of the 500 patients, 70 patients (14.0%) developed TE during the follow-up period. TEi was 9.2% and 17.3% in GCC patients, 18.1% and 3.5% in active and non-active cancer patients, and 24.0% and 12.9% in multiple and single primary, respectively. Multivariate logistic regression analysis showed that colorectal cancer (CRC) (OR 2.371; 95% CI 1.328 to 4.233), active cancer (OR 7.593; 95% CI 2.950 to 19.543) and multiple primary (OR 2.527; 95% CI 1.189 to 5.370) were independently associated with TEi. CONCLUSION: TEi was 14.0% among Japanese GCC patients received chemotherapy, and was significantly higher among patients with CRC, active cancer and multiple primary than among those with gastric cancer, non-active cancer and single primary, respectively. TRIAL REGISTRATION NUMBER: UMIN000018912.

[A Case of Malignant Peritoneal Mesothelioma Treated with Cisplatin and Pemetrexed].

A 65-year-old man was admitted to our hospital complaining of general malaise, anorexia and weight loss. A computed tomography(CT)scan showed massive ascites and multiple peritoneal masses. Although adenocarcinoma was suspected based on the cytology of the ascites, we were unable to determine the site of origin. We next performed a laparoscopy and a biopsy of the tumor on the omentum. The laparoscopy showed small, white, hard nodules that were disseminated throughout the abdominalcavity, and histologicaldiagnosis confirmed malignant peritonealmesothel ioma. The patient was administered chemotherapeutic treatment of cisplatin and pemetrexed. After treatment, the ascites decreased; however, tumor regression was not observed. The patient's performance status gradually decreased, and he died on hospital day 104. Prognosis of malignant peritoneal mesothelioma remains poor, and malignant peritoneal mesothelioma should be considered when diagnosing peritoneal tumors.

A Prospective Observational Study on Effect of Short-Term Periodic Steroid Premedication on Bone Metabolism in Gastrointestinal Cancer (ESPRESSO-01).

BACKGROUND: A multicenter prospective observational study evaluated the effect of gastrointestinal cancer chemotherapy with short-term periodic steroid premedication on bone metabolism. PATIENTS AND METHODS: Seventy-four patients undergoing chemotherapy for gastrointestinal cancer were studied. The primary endpoints were changes in bone mineral densities (BMDs) and metabolic bone turnover 16 weeks after initiation of chemotherapy. BMDs, measured by dual-energy x-ray absorptiometry, and serum cross-linked N-telopeptides of type I collagen (sNTX), and bone alkaline phosphatase (sBAP) were assessed for evaluation of bone resorption and formation, respectively. RESULTS: In 74.3% (55/74) of the patients, BMDs were significantly reduced at 16 weeks relative to baseline. The percent changes of BMD were -1.89% (95% confidence interval [CI], -2.67% to -1.11%: p < .0001) in the lumbar spine, -2.24% (95% CI, -3.59% to -0.89%: p = .002) in the total hip, and -2.05% (95% CI, -3.11% to -0.99%: p < .0001) in the femoral neck. Although there was no significant difference in sNTX levels during 16 weeks (p = .136), there was a significant increase in sBAP levels (p = .010). Decreased BMD was significantly linked to number of chemotherapy cycles (p = .02). There were no significant correlations between changes in BMDs and the primary site of malignancy, chemotherapy regimens, total cumulative steroid dose, steroid dose intensity, and additive steroid usage. CONCLUSION: Gastrointestinal cancer chemotherapy with periodic glucocorticoid premedication was associated with reduced BMD and increased sBAP levels, which were linked to number of chemotherapy cycles but independent of primary site, chemotherapy regimen, duration, and additive steroid usage. The Oncologist 2017;22:592-600 IMPLICATIONS FOR PRACTICE: Bone health and the management of treatment-related bone loss are important for cancer care. The present study showed that a significant decrease in bone mineral density (BMD) and an increase in serum bone alkaline phosphatase levels occurred in gastrointestinal cancer patients receiving chemotherapy, which were linked to number of chemotherapy cycles but were independent of primary site, chemotherapy regimen, total steroid dose, and steroid dose intensity. Surprisingly, it seems that the decreasing BMD levels after only 16 weeks of chemotherapy for gastrointestinal cancer were comparable to that of 12-month adjuvant aromatase inhibitor therapy for early-stage breast cancer patients.

Three-dimensional structure-activity relationship study of belactosin A and its stereo- and regioisomers: development of potent proteasome inhibitors by a stereochemical diversity-oriented strategy.

The development of potent proteasome inhibitors based on the stereochemical diversity-oriented strategy using a conformationally rigid cyclopropane structure was investigated. Thus, a series of stereo- and regioisomeric analogs of belactosin A (2), a cyclopropane amino acid (methanoamino acid)-containing tripeptidic proteasome inhibitor, were designed, in which the central cyclopropane amino acid part was replaced with the corresponding stereo- or regioisomer. Using a series of stereoisomeric cyclopropane amino acid equivalents with the cis/trans, D/L, and syn/anti stereochemical diversity, which were previously developed by us, as key units, the target compounds were successfully synthesized. Biological evaluation showed that, as expected, compound activity changed depending on the stereochemistry of the central cyclopropane amino acid part: the trans/L-syn-isomer 7 and the cis/L-anti-isomer 9 were more than twice as potent as natural belactosin A (trans/L-anti-isomer). Furthermore, the tripeptidic compound 13, the synthetic precursor for the unnatural cis/L-anti-isomer 9, was identified as a highly potent proteasome inhibitor. This compound, which is 20 times as potent as belactosin A and is even more potent than the well-known inhibitor lactacystin (4), may be an effective lead for developing clinically useful anticancer drugs. These results show that the stereochemical diversity-oriented approach can be a powerful strategy for the development of highly active compounds in medicinal chemical studies.

Lysine 63-linked polyubiquitin chain may serve as a targeting signal for the 26S proteasome.

Recruitment of substrates to the 26S proteasome usually requires covalent attachment of the Lys48-linked polyubiquitin chain. In contrast, modifications with the Lys63-linked polyubiquitin chain and/or monomeric ubiquitin are generally thought to function in proteasome-independent cellular processes. Nevertheless, the ubiquitin chain-type specificity for the proteasomal targeting is still poorly understood, especially in vivo. Using mass spectrometry, we found that Rsp5, a ubiquitin-ligase in budding yeast, catalyzes the formation of Lys63-linked ubiquitin chains in vitro. Interestingly, the 26S proteasome degraded well the Lys63-linked ubiquitinated substrate in vitro. To examine whether Lys63-linked ubiquitination serves in degradation in vivo, we investigated the ubiquitination of Mga2-p120, a substrate of Rsp5. The polyubiquitinated p120 contained relatively high levels of Lys63-linkages, and the Lys63-linked chains were sufficient for the proteasome-binding and subsequent p120-processing. In addition, Lys63-linked chains as well as Lys48-linked chains were detected in the 26S proteasome-bound polyubiquitinated proteins. These results raise the possibility that Lys63-linked ubiquitin chain also serves as a targeting signal for the 26S proteaseome in vivo.

Regulation of the nuclear factor (NF)-kappaB pathway by ISGylation.

Post-translational modification with ISG15 (interferon-stimulated gene 15 kDa) (ISGylation) is mediated by a sequential reaction similar to ubiquitination, and various target proteins for ISGylation have been identified. We previously reported that ISGylation of the E2 ubiquitin-conjugating enzyme Ubc13 suppresses its E2 activity. Ubc13 forms a heterodimer with Uev1A, a ubiquitin-conjugating enzyme variant, and the Ubc13-Uev1A complex catalyzes the assembly of a Lys63-linked polyubiquitin chain, which plays a non-proteolytic role in the nuclear factor (NF)-kappaB pathway. In this study, we examined the effect of ISGylation on tumor necrosis factor receptor-associated factor (TRAF)-6/transforming growth factor beta-activated kinase (TAK)-1-dependent NF-kappaB activation. We found that expression of the ISGylation system suppresses NF-kappaB activation via TRAF6 and TAK1 and that the level of polyubiquitinated TRAF6 is reduced by expression of the ISGylation system. Taken together, the results suggest that the NF-kappaB pathway is negatively regulated by ISGylation.

Synthesis of 2,3- and 3,4-methanoamino acid equivalents with stereochemical diversity and their conversion into the tripeptide proteasome inhibitor belactosin a and its highly potent cis-cyclopropane stereoisomer.

A series of chiral 2,3- and 3,4-methanoamino acid equivalents of stereochemical diversity were designed and synthesized from our chiral cyclopropane units, using a diastereoselective Grignard addition with ( R)- or ( S)- t-butanesulfinyl imines as the key step. These equivalents were converted into the proteasome inhibitor belactosin A and its cis-cyclopropane stereoisomer. The unnatural cis-isomer was shown to be more than twice as potent as belactosin A as a proteasome inhibitor.

Intracellularly inducible, ubiquitin hydrolase-insensitive tandem ubiquitins inhibit the 26S proteasome activity and cell division.

We constructed polyubiquitin derivatives that contain a tandem repeat of ubiquitins and were insensitive to ubiquitin hydrolases. They were designated tandem ubiquitin (tUb) with the number of repeats, such as tUb2. When tUbs were expressed under the control of the GAL1 promoter in the wild-type yeast strain, growth was strongly inhibited. Under these conditions, the degradation of N-end rule substrates, a UFD substrate and Gcn4 was inhibited, indicating that the tUb inhibits 26S proteasome activity. Consistent with this, tUb binds to the 26S proteasome. We showed that tUb inhibited the in vitro degradation of polyubiquitinylated Sic1 by the 26S proteasome. When tUB6 messenger RNA was injected into Xenopus embryos, cell division was inhibited, suggesting that tUb can be used as a versatile inhibitor of the 26S proteasome.

Sem1p is a novel subunit of the 26 S proteasome from Saccharomyces cerevisiae.

The 26 S proteasome, which catalyzes degradation of polyubiquitinated proteins, is composed of the 20 S proteasome and the 19 S regulatory particle (RP). The RP is composed of the lid and base subcomplexes and regulates the catalytic activity of the 20 S proteasome. In this study, we carried out affinity purification of the lid and base subcomplexes from the tagged strains of Saccharomyces cerevisiae, and we found that the lid contains a small molecular mass protein, Sem1. The Sem1 protein binds with the 26 S proteasome isolated from a mutant with deletion of SEM1 but not with the 26 S proteasome from the wild type. The lid lacking Sem1 is unstable at a high salt concentration. The 19 S RP was immunoprecipitated together with Sem1 by immunoprecipitation using hemagglutinin epitope-tagged Sem1 as bait. Degradation of polyubiquitinated proteins in vivo or in vitro is impaired in the Sem1-deficient 26 S proteasome. In addition, genetic interaction between SEM1 and RPN10 was detected. The human Sem1 homologue hDSS1 was found to be a functional homologue of Sem1 and capable of interacting with the human 26 S proteasome. The results suggest that Sem1, possibly hDSS1, is a novel subunit of the 26 S proteasome and plays a role in ubiquitin-dependent proteolysis.

Identification of ubiquitin-like protein-binding subunits of the 26S proteasome.

Ubiquitin-like proteins Rad23 and Dsk2 have recently been shown to be capable of binding both polyubiquitin chains and the 26S proteasome. The ubiquitin-like domains (Ubls) of Rad23 and Dsk2 are indispensable for their interaction with the 26S proteasome, but the proteasome subunits capable of binding the Ubl have not been identified. Here, we report that the Ubls of both Rad23 and Dsk2 can bind with the 19S regulatory particle (RP) of the 26S proteasome in vivo and in vitro. A competition assay using the respective Ubls of Rad23 and Dsk2 revealed that they bind to the RP in a competitive manner. The base subcomplex of the RP was found to have the ability to bind the Ubl. By cross-linking experiments, Rpn1 and Rpn2 were identified as Ubl-binding subunits. Taken together, the results suggest that the Rpn1 and Rpn2 in the base subcomplex form the receptor for the ubiquitin-like protein.