Crawling the Web: miRNA's in tumours

Everyday, Scientist Live turns its eyes to the Web around it and highlights news and research across the Internet. Today we look at genetic variation in forest trees, miRNA's role in glioblastoma multiforme formation, and yet another smoking cessation trial.



A formidable question has driven forest geneticists ever since the first genetic markers became available: there is strong clinal and ecotypic variation in the growth traits of forest trees, but this is hardly ever reflected in similar patterns at genetic markers (or patterns of similar magnitude)-why? In this issue of Heredity, González-Martínez et al., 2008 present an elegant way of getting closer to an answer. Using statistical methods originally intended for studying human and livestock genetics, they show how two particular nucleotide changes influence drought tolerance in pines.

- "Molecular genetics: Trees' genes and traits link up." Heinze, B. Heredity (2008) 101, 3-4; doi:10.1038/hdy.2008.38; published online 14 May 2008



Glioblastoma multiforme (GBM) is an invariably fatal central nervous system tumor despite treatment with surgery, radiation, and chemotherapy. Further insights into the molecular and cellular mechanisms that drive GBM formation are required to improve patient outcome. MicroRNAs are emerging as important regulators of cellular differentiation and proliferation, and have been implicated in the etiology of a variety of cancers, yet the role of microRNAs in GBM remains poorly understood. In this study, we investigated the role of microRNAs in regulating the differentiation and proliferation of neural stem cells and glioblastoma-multiforme tumor cells.

- "miR-124 and miR-137 inhibit proliferation of GBM cells and induce differentiation of brain tumor stem cells." Silber, J. et al. BMC Medicine 2008, 6:14doi:10.1186/1741-7015-6-14



Tobacco dependence is the leading cause of preventable death and disabilities worldwide and nicotine is the main substance responsible for the addiction to tobacco. A vaccine against nicotine was tested in a 6-month randomized, double blind phase II smoking cessation study in 341 smokers with a subsequent 6-month follow-up period.

229 subjects were randomized to receive five intramuscular injections of the nicotine vaccine and 112 to receive placebo at monthly intervals. All subjects received individual behavioral smoking cessation counseling. The vaccine was safe, generally well tolerated and highly immunogenic, inducing a 100% antibody responder rate after the first injection. Point prevalence of abstinence at month 2 showed a statistically significant difference between subjects treated with Nicotine-Qβ (47.2%) and placebo (35.1%) (P = 0.036), but continuous abstinence between months 2 and 6 was not significantly different. However, in subgroup analysis of the per-protocol population, the third of subjects with highest antibody levels showed higher continuous abstinence from month 2 until month 6 (56.6%) than placebo treated participants (31.3%) (OR 2.9; P = 0.004) while medium and low antibody levels did not increase abstinence rates. After 12 month, the difference in continuous abstinence rate between subjects on placebo and those with high antibody response was maintained (difference 20.2%, P = 0.012).

Whereas Nicotine-Qβ did not significantly increase continuous abstinence rates in the intention-to-treat population, subgroup analyses of the per-protocol population suggest that such a vaccination against nicotine can significantly increase continuous abstinence rates in smokers when sufficiently high antibody levels are achieved. Immunotherapy might open a new avenue to the treatment of nicotine addiction.

- "A Vaccine against Nicotine for Smoking Cessation: A Randomized Controlled Trial." Cornuz J, Zwahlen S, Jungi WF, Osterwalder J, Klingler K, et al. (2008) A Vaccine against Nicotine for Smoking Cessation: A Randomized Controlled Trial. PLoS ONE 3(6): e2547. doi:10.1371/journal.pone.0002547


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