CD133 and DNA-PK regulate MDR1 via the PI3K- or Akt-NF-κB pathway in multidrug-resistant glioblastoma cells in vitro

Chemotherapy is an adjuvant treatment for glioblastomas, however, chemotherapy remains palliative because of the development of multidrug resistance (MDR). Following prolonged chemotherapy, MDR protein 1 (MDR1) and CD133 increase in recurrent glioblastomas. CD133 positive (CD133+) glioma cancer stem-like cells (GCSCs) markedly promote drug resistance and exhibit increased DNA damage repair capability; thus they have a key role in determining tumor chemosensitivity. Although CD133, DNA-dependent protein kinase (DNA-PK), and MDR1 are elevated in CD133+ GCSCs, the relationship among these molecules has not been elucidated. In this study, MDR glioblastoma cell lines were created in response to prolonged doxorubicin chemotherapy. CD133, DNA-PK and MDR1 were markedly elevated in these cells. CD133 and DNA-PK may increase MDR1 via the phosphatidylinositol-3-kinase (PI3K)-Akt signal pathway. PI3K downstream targets Akt and nuclear factor (NF)-κB, which interacts with the MDR1 promoter, were also elevated in these cells. Downregulation of CD133 and DNA-PK by small interfering RNA, or inhibition of PI3K or Akt, decreased Akt, NF-κB and MDR1 expression. The results indicate that CD133 and DNA-PK regulate MDR1 through the PI3K- or Akt-NF-κB signal pathway. Consequently, a novel chemotherapeutic regimen targeting CD133 and DNA-PK in combination with traditional protocols may increase chemotherapeutic efficacy and improve prognosis for individuals who present with glioblastoma.

Human serum amyloid A3 (SAA3) protein, expressed as a fusion protein with SAA2, binds the oxidized low density lipoprotein receptor

Serum amyloid A3 (SAA3) possesses characteristics distinct from the other serum amyloid A isoforms, SAA1, SAA2, and SAA4. High density lipoprotein contains the latter three isoforms, but not SAA3. The expression of mouse SAA3 (mSAA3) is known to be up-regulated extrahepatically in inflammatory responses, and acts as an endogenous ligand for the toll-like receptor 4/MD-2 complex. We previously reported that mSAA3 plays an important role in facilitating tumor metastasis by attracting circulating tumor cells and enhancing hyperpermeability in the lungs. On the other hand, human SAA3 (hSAA3) has long been regarded as a pseudogene, which is in contrast to the abundant expression levels of the other isoforms. Although the nucleotide sequence of hSAA3 is very similar to that of the other SAAs, a single oligonucleotide insertion in exon 2 causes a frame-shift to generate a unique amino acid sequence. In the present study, we identified that hSAA3 was transcribed in the hSAA2-SAA3 fusion transcripts of several human cell lines. In the fusion transcript, hSAA2 exon 3 was connected to hSAA3 exon 1 or hSAA3 exon 2, located approximately 130kb downstream from hSAA2 exon 3 in the genome, which suggested that it is produced by alternative splicing. Furthermore, we succeeded in detecting and isolating hSAA3 protein for the first time by an immunoprecipitation-enzyme linked immune assay system using monoclonal and polyclonal antibodies that recognize the hSAA3 unique amino acid sequence. We also demonstrated that hSAA3 bound oxidized low density lipoprotein receptor (oxLDL receptor, LOX-1) and elevated the phosphorylation of ERK, the intracellular MAP-kinase signaling protein.

Assessment of lipophilic vs. hydrophilic statin therapy in acute myocardial infarction – ALPS-AMI study

BACKGROUND

Statins reduce the incidence of cardiovascular events, but no randomized trial has investigated the best statins for secondary prevention. We compared the efficacy of hydrophilic pravastatin with that of lipophilic atorvastatin in patients with acute myocardial infarction (AMI).

METHODS AND RESULTS

A prospective, multicenter study enrolled 508 patients (410 men; mean age, 66.0 ± 11.6 years) with AMI who were randomly assigned to atorvastatin (n=255) or pravastatin (n=253). The target control level of low-density lipoprotein cholesterol (LDL-C) was <100 mg/dl, and patients were followed for 2 years. The primary endpoint was the composite of death due to any cause, non-fatal myocardial infarction, non-fatal stroke, unstable angina or congestive heart failure requiring hospital admission, or any type of coronary revascularization. The primary endpoint occurred in 77 patients (30.4%) and in 80 patients (31.4%) in the pravastatin and atorvastatin groups, respectively (hazard ratio, 1.181; 95% confidence interval: 0.862-1.619; P=0.299), whereas greater reductions in serum total cholesterol and LDL-C were achieved in the atorvastatin group (P<0.001 for each). Changes in hemoglobin A1c, brain natriuretic peptide, and creatinine were not significant between the 2 regimens, and safety and treatment adherence were similar.

CONCLUSIONS

On 2-year comparison of hydrophilic and lipophilic statins there was no significant difference in prevention of secondary cardiovascular outcome.

Importance of fatty acid compositions in patients with peripheral arterial disease

OBJECTIVE

Importance of fatty acid components and imbalances has emerged in coronary heart disease. In this study, we analyzed fatty acids and ankle-brachial index (ABI) in a Japanese cohort.

METHODS

Peripheral arterial disease (PAD) was diagnosed in 101 patients by ABI ≤0.90 and/or by angiography. Traditional cardiovascular risk factors and components of serum fatty acids were examined in all patients (mean age 73.2±0.9 years; 81 males), and compared with those in 373 age- and sex-matched control subjects with no evidence of PAD.

RESULTS

The presence of PAD (mean ABI: 0.71±0.02) was independently associated with low levels of gamma-linolenic acid (GLA) (OR: 0.90; 95% CI: 0.85-0.96; P = 0.002), eicosapentaenoic acid∶arachidonic acid (EPA∶AA) ratio (OR: 0.38; 95% CI: 0.17-0.86; P = 0.021), and estimated glomerular filtration rate (OR: 0.97; 95% CI: 0.96-0.98; P<0.0001), and with a high hemoglobin A1c level (OR: 1.34; 95% CI: 1.06-1.69; P = 0.013). Individuals with lower levels of GLA (≤7.95 µg/mL) and a lower EPA∶AA ratio (≤0.55) had the lowest ABI (0.96±0.02, N = 90), while the highest ABI (1.12±0.01, N = 78) was observed in individuals with higher values of both GLA and EPA∶AA ratio (P<0.0001).

CONCLUSION

A low level of GLA and a low EPA∶AA ratio are independently associated with the presence of PAD. Specific fatty acid abnormalities and imbalances could lead to new strategies for risk stratification and prevention in PAD patients.

IL-22 produced by cancer-associated fibroblasts promotes gastric cancer cell invasion via STAT3 and ERK signaling

BACKGROUND

Interleukin-22 (IL-22) has been recently highlighted owing to its biological significance in the modulation of tissue responses during inflammation. However, the role of IL-22 in carcinogenesis has remained unclear. Here, we investigated the pathophysiological significance of IL-22 expression in gastric cancer tissues and examined the mechanism by which IL-22 promotes gastric cancer cell invasion.

METHODS

Human gastric cancer specimens were analysed by immunohistochemistry for expression of IL-22 and IL-22 receptor 1 (IL-22R1). The effects of IL-22-induced STAT3 and ERK signalling on invasive ability of gastric cancer cells were examined using a small-interfering RNA system and specific inhibitors. AGS cells were co-cultured with cancer-associated fibroblasts (CAFs) from human gastric cancer tissues and assessed by invasion assay.

RESULTS

Interleukin-22 and its receptor were expressed in α-smooth muscle actin-positive stromal cells and tumour cells at the invasive front of gastric cancer tissues, respectively. The expression of IL-22 and IL-22R1 was significantly related to lymphatic invasion. Interleukin-22 treatment promoted the invasive ability of gastric cancer cells through STAT3 and ERK activation. The invasive ability of gastric cancer cells was significantly enhanced by co-culture with IL-22-expressing CAFs.

CONCLUSIONS

Interleukin-22 produced by CAFs promotes gastric cancer cell invasion via STAT3 and ERK signalling.

Effect of rikkunshito on the expression of substance P and CGRP in dorsal root ganglion neurons and voluntary movement in rats with experimental reflux esophagitis

BACKGROUND

While there are reports that the herbal medicine rikkunshito (RKT) relieves upper gastrointestinal disease symptoms, the effect of RKT on primary afferent neurons is unknown.

METHODS

A model of reflux esophagitis (RE) was implemented using male Wistar rats aged 6-7 weeks. Ten days after surgery, the total area of esophageal mucosal erosion sites was determined. Th8-10 dorsal root ganglia (DRG) were dissected out and the expression of substance P (SP), calcitonin gene-related peptide (CGRP), and phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) was determined in DRG using immunohistochemistry. RKT (0.6%/WV) or omeprazole (OME) (10 mg/kg) was administered for 10 days beginning on the day after surgery. Voluntary movement was measured with an infrared sensor for 22 h each day.

KEY RESULTS

RE rats showed esophageal mucosal erosion and significantly increased number of SP/CGRP- and p-ERK1/2-immunoreactive neurons in DRG. Treatment with OME improved the size of erosive lesions in the esophageal mucosa of RE rats, while RKT did not. Treatment with RKT or OME significantly reduced the expression of SP/CGRP and p-ERK1/2 in DRG, and significantly increased voluntary movement in RE rats.

CONCLUSIONS & INFERENCES

RKT inhibited the activation of ERK1/2 and decreased the expression of SP and CGRP in DRG of RE rats, which may be associated with the observed amelioration of voluntary movement.

Indomethacin-induced generation of reactive oxygen species leads to epithelial cell injury before the formation of intestinal lesions in mice

Recently, with the increasing number of elderly patients who continuously take aspirin and/or nonsteroidal anti-inflammatory drugs (NSAIDs), the number of cases of severe hemorrhagic gastrointestinal (GI) bleeding is also on the increase. Gastric acid has been reported to play the most important role in hemorrhagic gastric mucosal injury. However, the pathogenesis of NSAID-derived mucosal injury in the intestine, where there is no acidic environment, remains unknown. We previously reported that NSAID-derived mitochondrial reactive oxygen species (ROS) are directly involved in GI cellular injury in vitro, although an in vivo study has not yet been carried out. In this study, we investigated the relationship between NSAID-derived ROS and intestinal injury formation. For this purpose, intestinal mucosal live imaging in mice was carried out using an ROS-indicating fluorescent probe. Treatment with indomethacin caused macroscopic intestinal injury in mice; however, many dying cells were observed even in areas that macroscopically appeared to have no injury after treatment with indomethacin. A fluorescent probe revealed that mucosal cells in the apparently uninjured areas had a high concentration of ROS. Treatment with rebamipide significantly decreased both the ROS concentration and the number of dying cells: this drug is prescribed clinically for gastric injury patients and has been reported to upregulate the expression of manganese superoxide dismutase. On the basis of these results, we propose that NSAID treatment causes a high cellular concentration of ROS in mucosae, possibly decreasing mucosal organo-protective efficacy. Moreover, intestinal food contents are likely to damage the mucosal structure when it is in such a fragile condition.

Prognostic Improvement by Multidisciplinary Therapy in Patients With Critical Limb Ischemia

Although limb salvage rate has improved in critical limb ischemia (CLI), an improvement in CLI prognosis has been scarcely reported. Multidisciplinary therapy (MT) including revascularization, wound bed preparation, treatment of comorbidity, and education of patients with CLI may improve prognosis. The aim of this study was to investigate the effectiveness of MT in prognostic improvement. We retrospectively analyzed 72 patients with CLI and assessed whether MT improved prognosis. The incidence of amputation-free survival (freedom from major amputation [MA] and death) was significantly different between the MT and conventional groups at 2 years (0% vs 33%; P = .024). After multivariate analysis, transfusion (hazard ratio [HR] 5.778; 95% confidence interval [CI], 2.372-14.073; P < .001), multivessel coronary disease (HR 3.353; 95% CI, 1.309-8.590; P = .012), and C-reactive protein >5 mg/dL (HR 3.958; 95% CI, 1.359-11.531; P = .012) were independent predictors for MA or death. We concluded that MT was effective in improved mortality and limb salvage rate.

Infective endocarditis associated with mitral valve prolapse in a patient with Klinefelter syndrome

We herein report a case of infective endocarditis associated with mitral valve prolapse (MVP) in a 34-year-old man with Klinefelter syndrome. The patient was admitted with a fever and headache that had persisted for three weeks. Repeated blood cultures showed growth of Streptococcus oralis. Echocardiography demonstrated severe mitral regurgitation with a large vegetation attached to the prolapsed anterior leaflet. Surgical plasty of the mitral valve was performed because the vegetation measured over 10 mm in diameter and there was a risk of recurrence of embolic complications. This case demonstrates the link between MVP and Klinefelter syndrome and highlights the importance of performing cardiovascular screening and preventing endocarditis.

Northernmost record of a whale shark Rhincodon typus from the Sea of Okhotsk

The whale shark Rhincodon typus is the world's largest fish and it occurs in tropical, subtropical and warm temperate waters. Here, the northernmost record of R. typus is reported, when it was found in the Sea of Okhotsk for the first time. This occurrence can be explained by the unusually high sea surface temperature during the summer of 2012.

Low Levels of High-Density Lipoprotein Cholesterol Predict the Presence of Coronary Artery Disease in Patients With Aortic Aneurysms

To identify predictors of the presence of coronary artery disease (CAD) in patients with planned surgery for aortic aneurysms, we reviewed clinical profiles and angiography records of 191 patients with aortic aneurysms (34 thoracic, 137 abdominal, and 20 thoracoabdominal; 162 men; mean age, 75.2 ± 7.7 years). The incidence of CAD was 38.7% among all the patients. Patients with CAD had significantly low levels of high-density lipoprotein cholesterol (HDL-C) as compared with patients without CAD (45 ± 9 vs 51 ± 13 mg/dL; P = .009). Multivariate analysis showed that only low HDL-C levels were associated with the presence of CAD (adjusted odds ratio, 0.946; 95% confidence interval, 0.911-0.983; P = .004). The optimal cutoff level of HDL-C to predict CAD was 47.50 mg/dL. The CAD is common in patients with aortic aneurysms, and low levels of HDL-C are independently associated with the presence of CAD.

Occurrence of the Chilean devil ray Mobula tarapacana (Elasmobranchii: Batoidea: Myliobatiformes) in the Sea of Okhotsk: first record from cold temperate waters

The northernmost record for Chilean devil ray Mobula tarapacana, a circumglobal species that occurs in tropical, subtropical and limited warm temperate waters, is described. An adult female was caught incidentally in the Sea of Okhotsk on 17 September 2011. This specimen is the first confirmed occurrence of devil rays Mobula spp. in cold temperate waters.