TASK DEFINITION: In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.
PROBLEM: Over the past three decades great efforts have been made in search of cancer chemoprevention strategies. The increase in knowledge of the long process from normal to cancer cell has enabled interventions in terms of lifestyle modifications, natural compounds or drugs to block or reverse the process. Great successes have been achieved, especially for breast and colorectal cancer. However, these strategies have yet to find clinical application on a large scale. In this article we identify the achievements, the pitfalls and the next steps to be taken to improve the efficacy and applicability of chemoprevention strategies. Among the crucial key points to be implemented are educational activities for physicians to appropriately disseminate the aim and indeed the culture of chemoprevention. It is essential to improve the risk-benefit balance, seeking the minimal active doses, intermittent schedules, a better characterization of the risk categories via a more personalized intervention based on individual characteristics, and ensure the containment of costs of public and private health prevention programs.

SOLUTION: Cancer chemoprevention: Much has been done, but there is still much to do. State of the art and possible new approaches.

PROBLEM: Glucagon is a 29-amino acid pancreatic hormone which counteracts the blood glucose-lowering action of insulin by stimulating hepatic glycogenolysis and gluconeogenesis1. The structure of the hamster pancreatic glucagon precursor has recently been determined from the sequence of a cloned cDNA2. Hamster preproglucagon is a 180-amino acid protein which contains five functional regions; a signal or pre-peptide, an NH2-terminal peptide (also called glicentin-related pancreatic peptide, GRPP), glucagon, and two carboxy-terminal glucagon-like peptides (GLP-1 and GLP-2). The sequences of two non-allelic anglerfish pancreatic glucagon precursors35 have also been determined and their organization is similar but not identical to the hamster protein; they lack the polypeptide segment corresponding to hamster GLP-2. The presence of three regions possessing internal homology, that is, glucagon, GLP-1 and GLP-2, within proglucagon, and the absence of GLP-2 in the anglerfish precursors suggests that the structure of the preproglucagon gene might provide insight into the evolution of this polyprotein. We have isolated and sequenced the human preproglucagon gene and report here that the organization of the human precursor deduced from this sequence is identical to the hamster protein. The gene contains at least three intervening sequences which divide the protein-coding portion of the gene into four regions corresponding to the signal peptide and part of the NH2-terminal peptide, the remainder of the NH2-terminal peptide and glucagon, GLP-1, and GLP-2. The data suggest that triplication and subsequent sequence divergence of an exon encoding glucagon or a glucagon-like peptide produced this polyprotein precursor.

SOLUTION: Exon duplication and divergence in the human preproglucagon gene

PROBLEM: Neuronal growth cones move forward by dynamically connecting actin-based motility to substrate adhesion, but the mechanisms at the individual molecular level remain unclear. We cultured primary neurons on N-cadherin-coated micropatterned substrates, and imaged adhesion and cytoskeletal proteins at the ventral surface of growth cones using single particle tracking combined to photoactivated localization microscopy (sptPALM). We demonstrate transient interactions in the second time scale between flowing actin filaments and immobilized N-cadherin/catenin complexes, translating into a local reduction of the actin retrograde flow. Normal actin flow on micropatterns was rescued by expression of a dominant negative N-cadherin construct competing for the coupling between actin and endogenous N-cadherin. Fluorescence recovery after photobleaching (FRAP) experiments confirmed the differential kinetics of actin and N-cadherin, and further revealed a 20% actin population confined at N-cadherin micropatterns, contributing to local actin accumulation. Computer simulations with relevant kinetic parameters modeled N-cadherin and actin turnover well, validating this mechanism. Such a combination of short- and long-lived interactions between the motile actin network and spatially restricted adhesive complexes represents a two-tiered clutch mechanism likely to sustain dynamic environment sensing and provide the force necessary for growth cone migration.

SOLUTION:
Two-tiered coupling between flowing actin and immobilized N-cadherin/catenin complexes in neuronal growth cones.