Plk3 Enhances Cisplatin Sensitivity of Nonsmall-Cell Lung Cancer Cells through Inhibition of the PI3K/AKT Pathway via Stabilizing PTEN.

Polo-like kinase 3 (Plk3) is involved in tumor development with a tumor suppressive function. However, the effect of Plk3 on the chemoresistance remains unclear. It has been documented that activation of the PI3K/AKT signaling pathway by PTEN loss significantly enhances chemoresistance in nonsmall-cell lung cancer (NSCLC). This study aims to evaluate the PTEN regulation by Plk3 and identify targets and underlying mechanisms that could be used to relieve chemoresistance. Our results showed that silencing Plk3 reduced PTEN expression and activated PI3K/AKT signaling by dephosphorylating and destabilizing PTEN in NSCLC cells. Reducing Plk3 expression promoted drug resistance to cisplatin (DDP), while overexpressing Plk3 promoted DDP sensitivity. However, these effects were attenuated when MK2206, a PI3K/AKT inhibitor, was applied. In conclusion, upregulation of Plk3 sensitized NSCLC cells toward DDP, which provides a potential target to restore DDP chemoresponse. We provided novel evidence that the PTEN/PI3K/AKT signaling pathway could be regulated by Plk3 through phosphorylation of PTEN and highlighted the critical role of Plk3 in the DDP resistance of NSCLC.

Association Between Metabolic Syndrome and the Risk of Lung Cancer: A Meta-Analysis.

Previous studies showed conflicting results regarding the association between metabolic syndrome (MetS) and risk of lung cancer. We performed a systemic review and meta-analysis to determine the relationship between MetS and lung cancer incidence and mortality in adults. Longitudinal follow-up studies were identified by search of Medline, Embase, Cochrane Library, and Web of Science. By incorporating potential heterogeneity into the model, a randomized-effects model was selected to pool the results. Fourteen observational studies were included. Pooled results showed that MetS was associated with a higher risk of lung cancer incidence [risk ratio (RR): 1.15, 95% confidence interval (CI): 1.05 to 1.26, p=0.002; I2=89%). Subgroup analysis suggested that the association was not significantly affected by study country, design, sex of the participants, adjustment of smoking, or different study quality scores (p for subgroup difference all>0.05). The association was predominantly contributed by studies with MetS defined by the National Cholesterol Education Program Adult Treatment Panel-III rather than those with MetS defined by the International Diabetes Foundation criteria, and the association seemed to be stronger in studies with follow-up within 6 years than those over 6 years (p for subgroup difference=0.03 and 0.04, respectively). In addition, pooled results also showed that MetS was associated with a higher risk of lung cancer mortality (RR: 1.46, 95% CI: 1.19 to 1.79, p <0.001; I2=0%). In conclusion, in adult population, MetS may be a risk factor of lung cancer incidence and mortality.

Pectin methylesterase and pectin remodelling differ in the fibre walls of two gossypium species with very different fibre properties.

Pectin, a major component of the primary cell walls of dicot plants, is synthesized in Golgi, secreted into the wall as methylesters and subsequently de-esterified by pectin methylesterase (PME). Pectin remodelling by PMEs is known to be important in regulating cell expansion in plants, but has been poorly studied in cotton. In this study, genome-wide analysis showed that PMEs are a large multi-gene family (81 genes) in diploid cotton (Gossypium raimondii), an expansion over the 66 in Arabidopsis and suggests the evolution of new functions in cotton. Relatively few PME genes are expressed highly in fibres based on EST abundance and the five most abundant in fibres were cloned and sequenced from two cotton species. Their significant sequence differences and their stage-specific expression in fibres within a species suggest sub-specialisation during fibre development. We determined the transcript abundance of the five fibre PMEs, total PME enzyme activity, pectin content and extent of de-methylesterification of the pectin in fibre walls of the two cotton species over the first 25-30 days of fibre growth. There was a higher transcript abundance of fibre-PMEs and a higher total PME enzyme activity in G. barbadense (Gb) than in G. hirsutum (Gh) fibres, particularly during late fibre elongation. Total pectin was high, but de-esterified pectin was low during fibre elongation (5-12 dpa) in both Gh and Gb. De-esterified pectin levels rose thereafter when total PME activity increased and this occurred earlier in Gb fibres resulting in a lower degree of esterification in Gb fibres between 17 and 22 dpa. Gb fibres are finer and longer than those of Gh, so differences in pectin remodelling during the transition to wall thickening may be an important factor in influencing final fibre diameter and length, two key quality attributes of cotton fibres.

Expression of vacuolar H+-pyrophosphatase (OVP3) is under control of an anoxia-inducible promoter in rice.

Vacuolar H(+)-pyrophosphatase (V-PPase) expression increases in a number of abiotic stresses and is thought to play a role in adaptation to abiotic stresses. This paper reports on the regulation of six V-PPase genes in rice (Oryza sativa L.) coleoptiles under anoxia, using flood tolerant and intolerant cultivars to test our hypothesis. Quantitative PCR analysis showed that one vacuolar H(+)-pyrophosphatase (OVP3) was induced by anoxia, particularly in flood-tolerant rice. Regulation of OVP3 expression under anoxia was investigated by analysing putative OVP promoters. The putative OVP3 promoter contained more previously identified anoxia-inducible motifs than the putative promoters of the other five OVP genes. GUS activity in transgenic rice plants containing the OVP3 promoter region linked to the GUS reporter gene was induced only by anoxia. Salt and cold treatments had little effect on OVP3 promoter-driven GUS expression when compared to the anoxic treatment.

[Structure identification of jujuboside D].

AIM: To study the chemical constituents of Ziziphus jujuba Mill var. Spinosa (Bunge) Hu ex. H. F. Chou. METHODS: To separate the constituents by using various kinds of chromatography and identify their structures on the basis of spectral analysis. RESULTS: Five compounds were isolated and their structures were established as jujuboside D (1), jujuboside A (2), 5,7,4'-trihydroxyflavonol-3-O-beta-D-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (3), 6'''-coumaroylspinosin (4) and phenylalanine (5). CONCLUSION: Compound 1 is a new compound named jujuboside D, 4 is reported as rotamer for the first time, 3 and 5 isolated from this plant for the first time.