A genome scale RNAi screen identifies GLI1 as a novel gene regulating vorinostat sensitivity.

Vorinostat is an FDA-approved histone deacetylase inhibitor (HDACi) that has proven clinical success in some patients; however, it remains unclear why certain patients remain unresponsive to this agent and other HDACis. Constitutive STAT (signal transducer and activator of transcription) activation, overexpression of prosurvival Bcl-2 proteins and loss of HR23B have been identified as potential biomarkers of HDACi resistance; however, none have yet been used to aid the clinical utility of HDACi. Herein, we aimed to further elucidate vorinostat-resistance mechanisms through a functional genomics screen to identify novel genes that when knocked down by RNA interference (RNAi) sensitized cells to vorinostat-induced apoptosis. A synthetic lethal functional screen using a whole-genome protein-coding RNAi library was used to identify genes that when knocked down cooperated with vorinostat to induce tumor cell apoptosis in otherwise resistant cells. Through iterative screening, we identified 10 vorinostat-resistance candidate genes that sensitized specifically to vorinostat. One of these vorinostat-resistance genes was GLI1, an oncogene not previously known to regulate the activity of HDACi. Treatment of vorinostat-resistant cells with the GLI1 small-molecule inhibitor, GANT61, phenocopied the effect of GLI1 knockdown. The mechanism by which GLI1 loss of function sensitized tumor cells to vorinostat-induced apoptosis is at least in part through interactions with vorinostat to alter gene expression in a manner that favored apoptosis. Upon GLI1 knockdown and vorinostat treatment, BCL2L1 expression was repressed and overexpression of BCL2L1 inhibited GLI1-knockdown-mediated vorinostat sensitization. Taken together, we present the identification and characterization of GLI1 as a new HDACi resistance gene, providing a strong rationale for development of GLI1 inhibitors for clinical use in combination with HDACi therapy.

Ferromagnetism of 3He films in the low-field limit.

We provide evidence for a finite-temperature ferromagnetic transition in two dimensions as H -->0 in thin films of 3He on graphite, a model system for the study of two-dimensional magnetism. We perform pulsed and cw NMR experiments at fields of 0.03-0.48 mT on 3He at areal densities of 20.5-24.2 atoms/nm(2). At these densities, the second layer of 3He has a strongly ferromagnetic tendency. With decreasing temperature, we find a rapid onset of magnetization that becomes independent of the applied field at temperatures in the vicinity of 1 mK. Both the dipolar field and the NMR linewidth grow rapidly as well, which is consistent with a large (order unity) polarization of the 3He spins.

Effect of anthelmintic treatment on the milk yield of dairy cows in England, Scotland and Wales.

One hundred and twenty dairy herds collaborated in a trial to determine the effect on milk yield of anthelmintic treatment given at calving. Cows and heifers were divided into five groups. Three were each given a different anthelmintic: thiabendazole, fenbendazole or levamisole. One group was given a placebo and the fifth was untreated. Analysis of data from 9000 lactations showed a treatment effect just significant at the 5 per cent level, of 42 kg milk, 1.8 kg fat and 1.4 kg protein. There was no evidence that the three anthelmintics differed in their effect on yield. The effect of treatment was not greater in heifers than in cows, nor was there a difference between spring and autumn calvers. There was no indication that the effect of treatment was markedly greater in some herds than others and it was not related to periparturient faecal egg count.

Effect of progesterone treatment on the calving-to-conception interval of Friesian dairy cows.

A total of 615 autumn calving Friesian dairy cows in seven herds were allocated to treatment or control groups according to date of previous calving, parity and milk yield. All cows were scored for body condition at the start of the breeding season. A silastic coil impregnated with progesterone with a capsule containing oestradiol benzoate attached was inserted into the vaginas of the 310 treated cows. The coils were removed after 12 days and cows inseminated 48 and 72 hours later. Cows more than 47 days post partum were inseminated on the first day of the breeding season. Thereafter, cows were inseminated on a weekly basis when between 47 to 54 days post partum. The 305 control cows were observed from 42 days post partum and inseminated when observed to be in oestrus. In both groups, cows returning to service were reinseminated at observed oestrus. Pregnancy was diagnosed by milk progesterone assay and by rectal palpation. The mean intervals to first service were 74.8 days for the treated and 90.4 days for control cows. No significant differences were found in the pregnancy rates to first service, services per conception or barren percentage for treated and control groups respectively. The mean calving-to-conception intervals differed significantly, 93.1 days for treated and 107.3 days for control cows. There was no significant association between condition scores and either pregnancy rates to first service, barren percentage or calving-to-conception intervals.