Therapy with the probiotic bacteria B. Subtilis and E. faecalis are an effective and safe means for preventing VAP and the acquisition of PPMO colonization in the stomach.
Notch signaling pathway plays critical roles in human cancers, including osteosarcoma, suggesting that the discovery of specific agents targeting Notch would be extremely valuable for osteosarcoma. Our previous studies have shown that diallyl trisulfide (DATS) inhibits proliferation of osteosarcoma cells by triggering cell cycle arrest and apoptosis in vitro. However, the underlying mechanism is still unclear. In this study, we found that DATS suppressed cell survival, wound-healing capacity, invasion and angiogenesis in osteosarcoma cells. These effects were associated with decreased expression of Notch-1 and its downstream genes, such as vascular endothelial growth factor and matrix metalloproteinases, as well as increased expression of a panel of tumor-suppressive microRNAs (miRNAs), including miR-34a, miR-143, miR-145 and miR-200b/c that are typically lost in osteosarcoma. We also found that reexpression of miR-34a and miR-200b by transfection led to reduced expression of Notch-1, resulting in the inhibition of osteosarcoma cell proliferation, invasion and angiogenesis. These results clearly suggest that DATS inhibited osteosarcoma growth and aggressiveness via a novel mechanism targeting a Notch-miRNA regulatory circuit. Our data provide the first evidence that the downregulation of Notch-1 and reexpression of miRNAs by DATS may be an effective approach for the treatment of osteosarcoma.
The Notch signaling pathway plays critical roles in human cancers, including osteosarcoma, suggesting that the discovery of specific agents targeting Notch would be extremely valuable for osteosarcoma. Curcumin, a naturally occurring phenolic compound found in curcuma longa, has been shown to inhibit proliferation and induce apoptosis of osteosarcoma cells in vitro and tumor growth in xenotransplant or orthotransplant models. However, the precise molecular mechanisms by which curcumin exerts its antitumor activity remain unclear. Here we used multiple molecular approaches, such as the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay, the invasion assay, gene transfection, real‐time RT‐PCR, western blot and gelatin zymography, to investigate whether the downregulation of Notch‐1 contributes to curcumin‐induced inhibition of proliferation and invasion in osteosarcoma cells. The results showed that curcumin caused marked inhibition of osteosarcoma cell growth and G2/M phase cell cycle arrest. This was associated with concomitant attenuation of Notch‐1 and downregulation of its downstream genes, such as matrix metalloproteinases, resulting in the inhibition of osteosarcoma cell invasion through Matrigel. We also found that specific downregulation of Notch‐1 via small‐interfering RNA prior to curcumin treatment resulted in enhanced inhibition of cell growth and invasion. These results suggest that antitumor activity of curcumin is mediated through a novel mechanism involving inactivation of the Notch‐1 signaling pathway. Our data provide the first evidence that the downregulation of Notch‐1 by curcumin may be an effective approach for the treatment of osteosarcoma.
SpyTag can spontaneously form a covalent isopeptide bond with its protein partner SpyCatcher. Firefly luciferase from Photinus pyralis was cyclized in vivo by fusing SpyCatcher at the N terminus and SpyTag at the C terminus. Circular LUC was more thermostable and alkali-tolerant than the wild type, without compromising the specific activity. Structural analysis indicated that the cyclized LUC increased the thermodynamic stability of the structure and remained more properly folded at high temperatures when compared with the wild type. We also prepared an N-terminally and C-terminally shortened form of the SpyCatcher protein and cyclization using this truncated form led to even more thermostability than the original form. Our findings suggest that cyclization with SpyTag and SpyCatcher is a promising and effective strategy to enhance thermostability of enzymes.
BackgroundAbnormal serum lipid levels have been shown to be associated with the occurrence of atherosclerosis, but little is known about the relationships of them with the risk of developing intervertebral disc degeneration (IVDD) in Chinese population.MethodsWe performed a case–control study to assess the relationship between serum lipid levels and lumbar disc degeneration. A total of 790 Chinese patients were recruited for this study at the time of hospitalization. We examined fasting serum lipid levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). 396 patients (235 men and 161 women; mean age: 41.07 years) underwent surgery for single-level lumbar disc herniation. A control group of 394 patients (225 men and 169 women; mean age: 42.1 years) underwent surgery for wounded lower limbs during the same period. Patients in the control group were collected randomly from among patients who were age- and sex-matched patients with the case group.ResultsPatients with lumbar disc herniation had significantly higher TC and LDL-C serum concentrations (P < 0.001 for both) than controls. Percentage of High-TC, High-TG, High-LDL-C, borderline High-TC and borderline High-LDL-C were significantly higher in the disc herniation group (P = 0.017, P = 0.002, P = 0.039, P =0.002 and P < 0.001, respectively). Ratios of TC/HDL-C and LDL-C/HDL-C were significantly associated with disc herniation (P < 0.001 for both). Logistic regression revealed that patients with higher serum LDL-C levels had a higher risk of disc herniation, in which odds ratio (OR) was 1.462 and confidence interval (CI) was 1.179 ~ 1.813. Moreover, patients with High-TG and borderline High-LDL-C had a higher probability of disc herniation (OR: 2.974, CI: 1.488 ~ 5.945, statistical power: 100 %; OR: 1.626, CI: 1.012 ~ 2.612, statistical power: 61.4 %, respectively). However, hyperlipidaemia did not seem to be associated with the herniated segment of the lumbar intervertebral disc (p = 0.374).ConclusionsThe present study suggests that dyslipidaemia may be associated with a higher risk of developing lumbar disc herniation. Serum lipid levels could be a useful predictor for intervertebral disc degeneration in Chinese population.
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