Four different types of small RNAs functionally associated with gene silencing have been discovered in animals including small interfering RNAs (siRNAs), microRNAs (miRNAs), and Piwi-interacting RNAs (piRNAs). Experimental evidence suggests that miRNAs regulate the expression of more than 30% of protein-coding genes. These molecules can also act as oncogenes or tumor suppressors. Expression profiling has revealed characteristic miRNA signatures not only in human cancers but also in serum and blood cells of cancer patients. Numerous human miRNA genes map to chromosomal regions which are susceptible to amplification, deletion or translocation in the process of tumor development. Despite the pivotal role of miRNA in cancer precise mechanisms of action are yet to be elucidated. This review is focused on recent findings related to the emerging field of miRNA serving as novel potential biomarkers in cancer diagnosis, prognosis and possibly, therapies.

Introduction: Trefoil factor family member 2 (Tff2) is a small gut peptide, mainly known for its protective and healing functions. As previously demonstrated, high-fat (HF) feeding can rapidly and specifically modulate Tff2 transcription in key tissues of mice, including the duodenum and mesenteric adipose tissue, therefore suggesting a novel role for this gene in energy balance. Design and Methods: To explore whether and how Tff2 can influence feeding behavior and energy metabolism, Tff2 knock-out (KO) mice were challenged with HF diet for 12 weeks, hence food and energy intakes, body composition, as well as energy excretion and serum lipid and hormonal levels were analyzed. Finally, energy efficiency was estimated. Results: Tff2 KO mice showed a greater appetite and higher energy intake compared to wild-type (WT). Consistently, they presented lower levels of serum leptin, and increased transcription of agouti-related protein (Agrp) in the hypothalamus. Though energy and triglyceride fecal excretion were augmented in Tff2 KO mice, digestible energy intake was superior. However, KO mice were finally protected from HF diet-induced obesity, and accumulated less weight and fat depots than WT animals, while keeping a normal lean mass. Energy efficiency was lower in HF-KO mice, while energy expenditure and locomotor activity were globally increased. Conclusions: The present work demonstrates previously unsuspected roles for Tff2 and suggests it to be a mastermind in the control of energy balance and a promising therapeutic target for obesity.

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A class of small, non-coding ribonucleic acids, termed microRNA (miRNA), has recently emerged as a new key player in the cellular control of gene expression. By either blocking translation or inducing target mRNA degradation, miRNA not only participates in regular biological processes within cells and tissues but is also involved in pathological processes. Many human malignancies have been linked to specific miRNA expression patterns, raising hopes for new approaches to therapy. While such human disease-related mechanisms have been widely discussed and frequently reviewed, miRNA's general significance in animals has been less in editorial focus, despite its obvious role in basic physiological processes, e.g. neurosensory maturation, development of fertility, and hibernation. Using selected examples, this review highlights our current knowledge of miRNA's potential and its promise as a new tool for gene regulation.

(2011) The intestinal factor Tff3 and a miRNA network regulate murine caloric metabolism, RNA Biology, 8:1,[77][78][79][80][81]