Vitamin B1 Intake and the Risk of Colorectal Cancer: a Systematic Review of Observational Studies.

Colorectal cancer is the main leading cause of death from cancer worldwide. Protective effects of vitamin B1 on colorectal cancer have been observed in some epidemiological studies. A systematic review and meta-analysis of observational studies evaluated the association of intake of vitamin B1 with the incidence of colorectal cancer. Relevant studies were identified in MEDLINE via PubMed (published up to September 2020). We extracted data from articles on vitamin B1 and used a multivariable-adjusted odds ratio (OR) and a random-effects model for analysis. We found seven articles meeting the inclusion criteria (1 of cohort studies and 6 case-control studies) and a total of 6,184 colorectal cancer cases were included in this meta-analysis. The multivariable-adjusted OR for pooled studies for the association of roughly the same high dose level versus the lowest vitamin B1 intake and the risk of colorectal cancer was 0.76 (95% confidence interval ([95%CI]: 0.65, 0.89). This meta-analysis studied the relationship between vitamin B1 and colorectal cancer. We found vitamin B1 intake was inversely associated with the risk of colorectal cancer. However, further research and large sample studies need to be conducted to better validate the result.

Overexpression of TNKS1BP1 in lung cancers and its involvement in homologous recombination pathway of DNA double-strand breaks.

TNKS1BP1 is a member of the poly(ADP-ribose) polymerase (PARP) superfamily. Our previous studies have demonstrated that TNKS1BP1 plays an important role in DNA damage response. But whether and how TNKS1BP1 associates with cancer is still not clear. Here, we found that TNKS1BP1 was upregulated in human lung adenocarcinoma (LAC) tissues, and was associated with poor overall survival (OS) in LAC patients. Dysregulation of TNKS1BP1 affected the sensitivity of A549 cells to several DNA damage agents including cisplatin, bleomycin, and ionizing radiation. Mechanically, overexpression of TNKS1BP1 increased the accumulation of S phase cells, which was accompanied by a decrease in M phase cells. More importantly, we found TNKS1BP1 regulated genome stability, mainly through affecting the homologous recombination pathway of DNA double-strand breaks by inhibiting the RAD51 foci formation. Overall, our study indicates that, in LAC, aberrant expressions of TNKS1BP1 are common events, and overexpression of TNKS1BP1 might affect outcomes of cancer patients to chemotherapy and radiotherapy.

DNA-PKcs associates with PLK1 and is involved in proper chromosome segregation and cytokinesis.

Accurate mitotic regulation is as important as intrinsic DNA repair for maintaining genomic stability. It is believed that these two cellular mechanisms are interconnected with DNA damage. DNA-PKcs is a critical component of the non-homologous end-joining pathway of DNA double-stranded break repair, and it was recently discovered to be involved in mitotic processing. However, the underlying mechanism of DNA-PKcs action in mitotic control is unknown. Here, we demonstrated that depletion of DNA-PKcs led to the dysregulation of mitotic progression in response to DNA damage, which eventually resulted in multiple failures, including failure to segregate sister chromatids and failure to complete cytokinesis, with daughter cells becoming fused again. The depletion of DNA-PKcs resulted in a notable failure of cytokinesis, with a high incidence of multinucleated cells. There were also cytoplasmic bridges containing DNA that continuously connected the daughter cells after DNA damage was induced. Phosphorylated DNA-PKcs (T2609) colocalizes with PLK1 throughout mitosis, including at the centrosomes from prophase to anaphase and at the kinetochores from prometaphase to metaphase, with accumulation at the midbody during cytokinesis. Importantly, DNA-PKcs was found to associate with PLK1 in the mitotic phase, and the depletion of DNA-PKcs resulted in the overexpression of PLK1 due to increased protein stability. However, deficiency in DNA-PKcs attenuated the recruitment of phosphorylated PLK1 to the midbody but not to the kinetochores and centrosomes. Our results demonstrate the functional association of DNA-PKcs with PLK1, especially in chromosomal segregation and cytokinesis control.

γH2AX foci formation in the absence of DNA damage: mitotic H2AX phosphorylation is mediated by the DNA-PKcs/CHK2 pathway.

Phosphorylated H2AX is considered to be a biomarker for DNA double-strand breaks (DSB), but recent evidence suggests that γH2AX does not always indicate the presence of DSB. Here we demonstrate the bimodal dynamic of H2AX phosphorylation induced by ionizing radiation, with the second peak appearing when G2/M arrest is induced. An increased level of γH2AX occurred in mitotic cells, and this increase was attenuated by DNA-PKcs inactivation or Chk2 depletion, but not by ATM inhibition. The phosphorylation-mimic CHK2-T68D abrogated the attenuation of mitotic γH2AX induced by DNA-PKcs inactivation. Thus, the DNA-PKcs/CHK2 pathway mediates the mitotic phosphorylation of H2AX in the absence of DNA damage.

4E-BP1 participates in maintaining spindle integrity and genomic stability via interacting with PLK1.

The essential function of eIF4E-binding protein 1 (4E-BP1) in translation initiation has been well established; however, the role of 4E-BP1 in normal cell cycle progression is coming to attention. Here, we revealed the role of 4E-BP1 on mitotic regulation and chromosomal DNA dynamics during mitosis. First, we have observed the co-localization of the phosphorylated 4E-BP1 at T37/46 with Polo-like kinase 1 (PLK1) at the centrosomes during. Depression of 4E-BP1 by small interfering RNA in HepG2 or HeLa cells resulted in an increased outcome of polyploidy and aberrant mitosis, including chromosomal DNA misaligned and multi-polar spindles or multiple centrosomes. We observed that 4E-BP1 interacted with PLK1 directly in vitro and in vivo in mitotic cells, and the C-terminal aa 77-118 of 4E-BP1 mediates its interaction with PLK1. PLK1 can phosphorylate 4E-BP1 in vitro. Furthermore, the depletion of 4E-BP1 sensitized HepG2 and HeLa cells to the microtubule disruption agent paclitaxel. These results demonstrate that 4E-BP1, beyond its role in translation regulation, can function as a regulator of mitosis via interacting with PLK1, and possibly plays a role in genomic stability maintaining.

[Analysis of chemical composition in the combination of monkshood and pinellia by UPLC/Q-TOFMS with multivariate statistical analysis].

In the present study, an ultra performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC/Q-TOFMS) based on chemical profiling approach to evaluate chemical constitution between mixed decoction and co-decoction of monkshood-pinellia combination of the eighteen incompatible medications (Shi Ba Fan) was proposed. Two different kinds of decoctions, namely monkshood-pinellia co-decoction: water extract of the two herbs together, and monkshood-pinellia mixed decoction: water extract of each individual herbs mixed together, were prepared. Batches of these two kinds of decoction samples were subjected to UPLC/Q-TOFMS analysis, the datasets were processed with MassLynx 4.1 to holistically compare the difference between these two kinds of decoction samples. The most changed components during decocting were analyzed. Using the proposed approach, global chemical difference was found between co-decoction and mixed decoction, mesaconitine, aconitine and hypaconitine were identified as the most changed components (changed most significantly) during decocting. Result shows significant difference between two kinds of decoction samples, and the significant differences are probably related to the incompatibility of monkshood and pinellia.

Probucol decreases asymmetrical dimethylarginine level by alternation of protein arginine methyltransferase I and dimethylarginine dimethylaminohydrolase activity.

HYPOTHESIS: Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor (NOS), may play an important role in endothelium dysfunction. Probucol, a potent antioxidant drug, may improve endothelium function via reduction of NOS inhibitor level. The present study examined whether the decreased level of ADMA by probucol is related to enhancement of protein arginine methyltransferase I (PRMT I) expression and reduction of dimethylarginine dimethylaminohydrolase (DDAH) activity. METHODS: Endothelial cells were cultured and used for all these studies. ADMA concentration and DDAH activity were determined by HPLC. Expression of PRMT I and eNOS were characterized by western blot. RESULTS: Pretreatment with oxidized-low density lipoprotein (ox-LDL) (10, 30 or 100 microg/ml) or lysophosphatidylcholine (LPC) (1.0, 2.5 or 5.0 microg/ml) for 12, 24 or 48 h markedly increased the activity of lactate dehydrogenase (LDH) in cultured endothelial cell. Incubation ofendothelial cells with ox-LDL (100 microg/ml) or LPC (5.0 microg/ml) for 48 h significantly increased the expression of PRMT I, and levels of MDA and ADMA, and decreased the concentration of nitrite/nitrate, the expression of eNOS and the activity of DDAH. Probucol significantly decreased the level of ADMA, concomitantly with reduction of PRMT I expression and elevation of DDAH activity and up-regulation of eNOS expression. CONCLUSION: In summary, the present results suggest that the protective effect of probucol on endothelium is related to reduction of ADMA concentration by inhibition of PRMT I expression and enhancement of DDAH activity.

Influence of ovariectomy and 17beta-estradiol treatment on insulin sensitivity, lipid metabolism and post-ischemic cardiac function.

The purpose of this study was to test whether the insulin sensitivity, lipid metabolism and the susceptibility of the heart to ischemia/reperfusion injury are modulated by the chronic estrogen status. Rats were ovariectomized (OVX), not ovariectomized (sham) or ovariectomized and treated with subcutaneous 17 -estradiol (30 mug/kg/day, OVX+E2) (n=14-17 per group). Within 3 months after operation, body weight, the serum levels of estrogen, glucose, insulin, total cholesterol (T-chol), HDL-chol, LDL-cholesterol (LDL-chol), triglycerides (TG) and lipoprotein a (Lp(a)) were monitored. Three months after operation, hearts of partial rats (n=6-8 per group) were isolated and allowed an initial 20-min stabilization period, and then cardiac function was recorded and creatine kinase (CK) release in the coronary effluent was measured after 4 h of hypothermic ischemia in isolated rat hearts. The experimental results showed that from 2 weeks after ovariectomy to the end of the study, body weights of OVX were significantly higher compared with the other two groups (p<0.05). On weeks 5 and 9, insulin level of OVX was significantly higher than that of the other two groups (p<0.05), whereas it was not different among the three groups on weeks 12 and 13 (p>0.05). Blood glucose on week 13 was significantly higher in OVX (p<0.05). Consequently, Insulin Sensitivity Index (ISI) of OVX was lower than that of the other two groups on weeks 5 and 9 (p<0.05), but not on weeks 12 and 13. Serum values for T-chol, HDL-chol and LDL-chol were not significantly different among the three groups within the observing period. On week 13, TG level in ovariectomized group was significantly lower than in the sham- and E2-treated groups (p<0.05). Compared with sham, Lp(a) level was slight increased in OVX rats (p<0.05), while it was further increased in E2-treated rats (p<0.05). Cardiac function (left ventricular pressure (LVP) and +/-dp/dtmax) of hearts removed from OVX rats was depressed, and CK release was markedly increased (p<0.05). However, treatment with E2 significantly improved cardiac function, as shown by increasing left ventricular pressure,+dp/dtmax and -dp/dtmax, and decreased CK release. In conclusion, chronic E2 treatment has some beneficial effects on cardiovascular disease (CVD), which come from the results of improvement of insulin sensitivity and post-ischemia cardiac function. However, the mechanism did not include changes in lipids and lipoproteins. The change in Lp(a) level shows that estrogen does not confer cardiovascular protection and may increase the risk of stroke.

Protective effects of rutaecarpine in cardiac anaphylactic injury is mediated by CGRP.

Previous investigations have indicated that rutaecarpine activates the vanilloid receptor to evoke calcitonin gene-related peptide (CGRP) release. CGRP has been shown to alleviate cardiac anaphylactic injury. In the present study, the effect of rutaecarpine on cardiac anaphylaxis was examined. Challenge of presensitized guinea-pig hearts with a specific antigen caused marked decreases in coronary flow (CF), left ventricular pressure (LVP) and its derivatives (+/- dp/dt(max)), an increase in heart rate, and prolongation of the P-R interval. Rutaecarpine (0.3 or 1 microM) markedly increased the content of calcitonin gene-related peptide (CGRP) in the coronary effluent and decreased the content of tumor necrosis factor-alpha (TNF-alpha) in myocardial tissues concomitantly with a significant improvement of cardiac function and alleviation of the extension of the P-R interval. Rutaecarpine at the concentration of 1 microM also inhibited the sinus tachycardia. The protective effects of rutaecarpine on cardiac anaphylaxis were abolished by CGRP (8-37), a selective CGRP receptor antagonist. These results suggest that the protective effects of rutaecarpine on cardiac anaphylactic injury are related to inhibition of TNF-alpha production by stimulation of CGRP release.

Protective effects of evodiamine on myocardial ischemia-reperfusion injury in rats.

Previous investigations have indicated that the pharmacological activities of evodiamine, a major alkaloidal component of the dried, unripe fruit of Evodia rutaecarpa Bentham (Rutaceae), are associated with the stimulation of calcitonin gene-related peptide (CGRP) release and that CGRP protects the myocardium against ischemia-reperfusion injury. In the present study, we have examined whether evodiamine protects against myocardial ischemia-reperfusion injury in rats and whether the protective effects of evodiamine are related to the activation of capsaicin-sensitive sensory nerves. Rats were pretreated with evodiamine 10 min before the experiment, and then the left main coronary artery of rat hearts was subjected to 60 min occlusion followed by 180 min reperfusion. Infarct size, the activity of serum creatine kinase, serum concentrations of TNF-alpha and plasma concentrations of CGRP were measured. Pretreatment with evodiamine (30 or 60 microg/kg, i.v.) markedly increased the content of CGRP in plasma concomitantly with a significant reduction in infarct size, the activity of serum creatine kinase, and TNF-alpha level, and the effects of evodiamine were completely abolished by capsazepine (5.0 mg/kg, s.c.), a competitive vanilloid receptor antagonist. These results suggest that evodiamine exerts a protection against myocardial ischemia-reperfusion injury in rats and that the protective effects of evodiamine are related to stimulation of CGRP release via activation of vanilloid receptors.

Protective effects of calcitonin gene-related peptide-mediated evodiamine on guinea-pig cardiac anaphylaxis.

Previous investigations have indicated that the pharmacological effects of evodiamine, a major alkaloidal component of the dried, unripe fruit of Evodia rutaecarpa Bentham (Rutaceae), are associated with stimulation of calcitonin gene-related peptide (CGRP) release and CGRP prevents cardiac anaphylactic injury. In the present study, the protective effects of evodiamine on cardiac anaphylaxis were examined. Presensitized guinea-pig hearts challenged with specific antigen (bovine serum albumin) caused a marked decrease in coronary flow, left ventricular pressure and its derivatives (+/-dp/dt(max)), an increase in heart rate, and prolongation of P-R interval. Evodiamine (0.3 microM or 1 microM) markedly increased the content of CGRP in the coronary effluent concomitantly with a significant improvement of cardiac function and alleviation of the extension of P-R interval. Evodiamine at the concentration of 1 microM also inhibited the sinus tachycardia. The protective effect of evodiamine on cardiac anaphylaxis was abolished by CGRP(8-37), the selective CGRP receptor antagonist. These results suggest that evodiamine possesses a protective effect of cardiac anaphylactic injury and that the effect of evodiamine is related to stimulation of CGRP release.