Choline kinase alpha depletion selectively kills tumoral cells.

Choline Kinase (ChoK) comprises a family of cytosolic enzymes involved in the synthesis of phosphatidylcholine (PC), the most abundant phospholipid in eukaryotic cell membranes. One of the ChoK isoforms, Choline Kinase alpha (ChoKalpha), is found over expressed in human tumours. Chemical inhibitors able to interfere with ChoK activity have proven to be effective antitumoral drugs in vitro and in vivo. To validate the use of selective ChoKalpha inhibitors in cancer therapy, we have developed a genetic strategy to interfere specifically with ChoKalpha activity based on the generation of a shRNA against the alpha isoform of ChoK. Here we demonstrate that specific inhibition of ChoKalpha by shRNA has antitumor activity. The specific depletion of ChoKalpha induces apoptosis in several tumor-derived cell lines from breast, bladder, lung and cervix carcinoma tumors, while the viability of normal primary cells is not affected. Furthermore, this selective antiproliferative effect is achieved both under in vitro and in vivo conditions, as demonstrated by an inducible ChoKalpha suppression system in human tumour xenografts. These results demonstrate that ChoKalpha inhibition is a useful antitumoral strategy per se, and provides definitive and non-ambiguous evidence that ChoKalpha can be used as an efficient and selective drug target for cancer therapy.

Overexpression of yeast hsp104 reduces polyglutamine aggregation and prolongs survival of a transgenic mouse model of Huntington's disease.

Huntington's disease is a devastating neurodegenerative condition associated with the formation of intraneuronal aggregates by mutant huntingtin. Aggregate formation is a property shared by the nine related diseases caused by polyglutamine codon expansion mutations and also by other neurodegenerative conditions like Parkinsons's disease. The roles of aggregates and aggregation in these diseases have been a subject of heated controversy. Here, we have addressed the question in vivo by generating a new transgenic mouse overexpressing the yeast chaperone hsp104, as hsp104 overexpression reduced mutant huntingtin aggregation and toxicity in cell models. Hsp104 has no close mammalian orthologues and does not appear to have effects on mammalian cell death pathways. We crossed hsp104 transgenic mice with mice expressing the first 171 residues of mutant huntingtin. Hsp104 reduced aggregate formation and prolonged the lifespan of the HD mice by 20%. This protection may be mediated at the level of changing the conformation of a putative toxic monomer, reducing oligomerization or aggregation, reducing the levels of oligomeric species or aggregates or combinations of these non-mutually exclusive possibilities.

Doxycycline attenuates and delays toxicity of the oculopharyngeal muscular dystrophy mutation in transgenic mice.

The muscular dystrophies are a heterogeneous group of disorders for which there are currently no cures. Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant late-onset, progressive disease that generally presents in the fifth or sixth decade with dysphagia, ptosis and proximal limb weakness. OPMD is caused by the abnormal expansion of a (GCG)n trinucleotide repeat in the coding region of the poly-(A) binding protein nuclear 1 (PABPN1) gene. In unaffected individuals, (GCG)6 codes for the first six alanines in a homopolymeric stretch of ten alanines. In most individuals with OPMD this (GCG)6 repeat is expanded to (GCG)8-13, leading to a stretch of 12-17 alanines in mutant PABPN1. PABPN1 with an expanded polyalanine tract forms aggregates consisting of tubular filaments within the nuclei of skeletal muscle fibers. We have developed a transgenic mouse model of OPMD that manifests progressive muscle weakness accompanied by intranuclear aggregates and TUNEL-stained nuclei in skeletal muscle fibers. The onset and severity of these abnormalities were substantially delayed and attenuated by doxycycline treatment, which may exert its therapeutic effect by reducing aggregates and by distinct antiapoptotic properties. Doxycycline may represent a safe and feasible therapeutic for this disease.