Highly stable meso-diaminopimelate dehydrogenase from an Ureibacillus thermosphaericus strain A1 isolated from a Japanese compost: purification, characterization and sequencing

We screened various thermophiles for meso-diaminopimelate dehydrogenase (meso-DAPDH, EC 1.4.1.16), which catalyzes the NAD(P)-dependent oxidative deamination of meso-diaminopimelate, and found the enzyme in a thermophilic bacterium isolated from compost in Japan. The bacterium grew well aerobically at around 55°C and was identified as Ureibacillus thermosphaericus strain A1. We purified the enzyme about 47-fold to homogeneity from crude cell extract using five successive purification steps. The molecular mass of the purified protein was about 80 kDa, and the molecule consists of a homodimer with the subunit molecular mass of about 40 kDa. The optimum pH and temperature for the catalytic activity of the enzyme are about 10.5 and 65°C, respectively. The enzyme is highly selective for meso-diaminopimelate as the electron donor, and NADP but not NAD can serve as the electron acceptor. The Km values for meso-diaminopimelate and NADP at 50°C and pH 10.5 are 1.6 mM and 0.13 mM, respectively. The nucleotide sequence of this meso-DAPDH gene encodes a 326-amino acid peptide. When the gene was cloned and overexpressed in Escherichia coli Rosetta (DE3), the specific activity in the crude extract of the recombinant cells was about 18.0-fold higher than in the extract from U. thermosphaericus strain A1. This made more rapid and simpler purification of the enzyme possible

Gastroduodenal Mucosal Injury and Antiplatelet Drug Users

Antiplatelet drugs are widely used for the prevention of cardiovascular disease and cerebral vascular disorders. Although there have been several studies on gastroduodenal mucosal injury with gastrointestinal (GI) symptoms such as GI bleeding, in antiplatelet drug users (including low-dose aspirin (LDA)), there have been few reports on the association between antiplatelet drug use and gastroduodenal mucosal injury in asymptomatic antiplatelet drug users. This study was a cross-sectional study elucidating the association between antiplatelet drug use and gastroduodenal mucosal injury in asymptomatic antiplatelet drug users. Subjects were 186 asymptomatic Japanese antiplatelet drug users who underwent a regular health checkup. Subjects were divided into those with and without gastroduodenal mucosal injury endoscopically, and the association between gastroduodenal mucosal injury and other data in asymptomatic antiplatelet drug users was investigated. The prevalence of males and drinkers were significantly higher in subjects with gastroduodenal mucosal injury than in those without. In addition, the prevalence of proton pump inhibitor (PPI) users was significantly lower in subjects with gastroduodenal mucosal injury than in subjects without gastroduodenal mucosal injury. Logistic regression analysis showed PPI (odds ratios: 0.116; 95% confidence intervals: 0.021–0.638; P < 0.05) was a significant predictor of a decreased prevalence of gastroduodenal mucosal injury and closed-type (C-type) atrophy (3.172; 1.322–7.609; P < 0.01) was a significant predictor of an increased prevalence of severe gastroduodenal mucosal injury in asymptomatic antiplatelet drug users. Gender and lifestyle, such as drinking, may have an impact on risk of gastroduodenal mucosal injury in asymptomatic subjects taking antiplatelet drugs. Although PPI is a significant predictor of a decreased prevalence of gastroduodenal mucosal injury, including in asymptomatic antiplatelet drug users, status of gastric atrophy should also be considered against severe gastroduodenal mucosal injury

Chemoradiotherapy with miriplatin

Background: The prognosis for patients with unresectable advanced hepatocellular carcinoma (HCC) is poor. Miriplatin is a hydrophobic platinum compound that has a long retention time in lesions after transarterial chemoembolization (TACE). We investigated anti-tumor activity of miriplatin combined with irradiation on HCC cells, and its underlying mechanism of apoptosis. We also analyzed the effectiveness of miriplatin-TACE and radiotherapy for locally advanced HCC. Methods: Human HCC cell lines HepG2 and HuH-7 were treated with DPC (active form of miriplatin) and radiation, and synergy was evaluated using a combination index (CI). Apoptosis-related proteins and cell cycles were analyzed by western blotting and flowcytometry. We retrospectively analyzed treatment outcomes in 10 unresectable HCC patients with vascular/bile duct invasion treated with miriplatin-TACE and radiotherapy. Results: DPC or X-ray irradiation decreased cell viability dose-dependently. DPC plus irradiation decreased cell viability synergistically in both cell lines (CI<1 respectively). Cleaved PARP expression was induced much more strongly by DPC plus irradiation than by each treatment alone. Expression of p53 up-regulated modulator of apoptosis (PUMA) was significantly induced by the combination, and knockdown of PUMA with siRNA significantly decreased apoptosis in both cell lines. DPC plus irradiation caused sub-G1, G2/M, and S phase cell arrest in those cells. The combination of miriplatin-TACE and radiotherapy showed a high response rate for patients with locally advanced HCC despite small number of patients. Conclusions: Miriplatin plus irradiation had synergistic anti-tumor activity on HCC cells through PUMA-mediated apoptosis and cell cycle arrest. This combination may possibly be effective in treating locally advanced HCC

Cancer genome profiling for GI cancers

In Japan, cancer genome profiling (CGP) for cancer patients without standard treatment has been covered by public insurance since June 2019. This study analyzed data of 122 patients with gastrointestinal tumors who underwent CGP to clarify cancer genome medicine’s current status and possible problems at the Tokushima University Hospital. The major types of cancer included pancreatic (n = 30), colorectal (n = 25), biliary tract (n = 15), gastric (n = 11), and hepatocellular carcinoma (n = 8). CGP tests included F1CDx in 70 patients (57%), F1LCDx in 36 (30%), TSO500 in 14 (11%), and NCC Oncopanel in 2 (2%). Actionable gene alterations were identified in 72 patients (59%), but only 5 patients (4%) were treated for pancreatic (n = 1), colorectal (n = 3), and small bowel cancers (n = 1). The main reasons for not receiving genotype-matched therapy included the lack of appropriate drugs or clinical trials that matched the actionable gene alterations (n = 40) and the inability to participate in clinical trials (n = 10). There is still not a sufficient number of patients receiving genotype-matched treatment for gastrointestinal cancers. To promote cancer genome medicine in regional areas, attempts to improve access to genotype-matched therapies are required, as well as to promote the development of new molecular-targeted drugs and clinical trials for these drugs

Potential use of lenvatinib for patients with unresectable hepatocellular carcinoma including after treatment with sorafenib : Real-world evidence and in vitro assessment via protein phosphorylation array

The efficacy and safety of lenvatinib (LEN) as a second/third-line treatment for unresectable hepatocellular carcinoma (HCC) after sorafenib (SOR) therapy remains unknown. We evaluated the outcomes of second/third-line LEN treatment, investigated the sensitivity of a SOR-resistant HCC cell line (PLC/PRF5-R2) to LEN, and assessed their signal transduction pathways by protein array analysis. We retrospectively enrolled 57 patients with unresectable HCC. Fifty-three radiologically evaluated patients comprised 34 molecular-targeted agent (MTA)-naive (first-line), nine intolerant to SOR (second-line), and 10 resistant to regorafenib (third-line). The objective response rates (ORRs) were 61.8% in first-line, 33.3% in second-line, and 20.0% in third-line groups. The overall survival (OS) in the first-line was significantly longer than that in the third-line group (p < 0.05). Patients with better liver functional reserves (child score, ALBI grade) exhibited higher ORR and longer OS. The IC50 of LEN against PLC/PRF5-R2 was significantly higher than that against PLC/PRF5. LEN significantly inhibited more LEN-related signal transduction pathways in PLC/PRF5 than in PLC/PRF5-R2 cells. This suggests that LEN is active and safe as a second/third-line treatment for unresectable HCC. LEN seems more effective for patients with HCC with better hepatic reserve functions or before MTA-resistance is acquired because of the partial cross-resistance to SOR

Sessile serrated adenoma/polyp-cancer sequenceにおいてS100Pは遺伝子脱メチル化により発現し、細胞増殖を促進する

Background/Aims: Sessile serrated adenomas/polyps (SSA/Ps) are a putative precursor lesion of colon cancer. Although the relevance of DNA hypermethylation in the SSA/P-cancer sequence is well documented, the role of DNA hypomethylation is unknown. We investigated the biological relevance of DNA hypomethylation in the SSA/P-cancer sequence by using 3-dimensional organoids of SSA/P. Methods: We first analyzed hypomethylated genes using datasets from our previous DNA methylation array analysis on 7 SSA/P and 2 cancer in SSA/P specimens. Expression levels of hypomethylated genes in SSA/P specimens were determined by RT-PCR and immunohistochemistry. We established 3-dimensional SSA/P organoids and performed knockdown experiments using a lentiviral shRNA vector. DNA hypomethylation at CpG sites of the gene was quantitated by MassARRAY analysis. Results: The mean number of hypomethylated genes in SSA/P and cancer in SSA/P was 41.6 ± 27.5 and 214 ± 19.8, respectively, showing a stepwise increment in hypomethylation during the SSA/P-cancer sequence. S100P, S100α2, PKP3, and MUC2 were most commonly hypomethylated in SSA/P specimens. The mRNA and protein expression levels of S100P, S100α2, and MUC2 were significantly elevated in SSA/P compared with normal colon tissues, as revealed by RT-PCR and immunohistochemistry, respectively. Among these, mRNA and protein levels were highest for S100P. Knockdown of the S100P gene using a lentiviral shRNA vector in 3-dimensional SSA/P organoids inhibited cell growth by >50% (p < 0.01). The mean diameter of SSA/P organoids with S100P gene knockdown was significantly smaller compared with control organoids. MassARRAY analysis of DNA hypomethylation in the S100P gene revealed significant hypomethylation at specific CpG sites in intron 1, exon 1, and the 5′-flanking promoter region. Conclusion: These results suggest that DNA hypomethylation, including S100P hypomethylation, is supposedly associated with the SSA/P-cancer sequence. S100P overexpression via DNA hypomethylation plays an important role in promoting cell growth in the SSA/P-cancer sequence