Drug‐microenvironment perturbations reveal resistance mechanisms and prognostic subgroups in CLL

The tumour microenvironment and genetic alterations collectively influence drug efficacy in cancer, but current evidence is limited and systematic analyses are lacking. Using chronic lymphocytic leukaemia (CLL) as a model disease, we investigated the influence of 17 microenvironmental stimuli on 12 drugs in 192 genetically characterised patient samples. Based on microenvironmental response, we identified four subgroups with distinct clinical outcomes beyond known prognostic markers. Response to multiple microenvironmental stimuli was amplified in trisomy 12 samples. Trisomy 12 was associated with a distinct epigenetic signature. Bromodomain inhibition reversed this epigenetic profile and could be used to target microenvironmental signalling in trisomy 12 CLL. We quantified the impact of microenvironmental stimuli on drug response and their dependence on genetic alterations, identifying interleukin 4 (IL4) and Toll‐like receptor (TLR) stimulation as the strongest actuators of drug resistance. IL4 and TLR signalling activity was increased in CLL‐infiltrated lymph nodes compared with healthy samples. High IL4 activity correlated with faster disease progression. The publicly available dataset can facilitate the investigation of cell‐extrinsic mechanisms of drug resistance and disease progression.     

Development and enhancement of agricultural biotechnology in some countries in Latin America

A number of research institutions and both local and international agencles in Latin America are using biotechnology as part of an effort to enhance agricultural productivity. However, it is very much an open question as to whether all of these various organizations can provide the best means of realizing this goal. Latin American countries vary dramatically in their knowledge base and current use of modern biotechnology. Thus, while some countries lack the ability to develop, or possibly even implement, many aspects of modern biotechnology, others are quite advanced in this regard. This review provides a somewhat selective overview of current research in the area of agricultural biotechnology in Mexico, Costa Rica and Ecuador, with emphasis on how the existing agencies and institutions have responded to the challenge of biotechnology. In addition, general strategies for the development of agricultural biotechnology in these countries are presented and discussed.     

Flavonol‐mediated stabilization of PIN efflux complexes regulates polar auxin transport

The transport of auxin controls the rate, direction and localization of plant growth and development. The course of auxin transport is defined by the polar subcellular localization of the PIN proteins, a family of auxin efflux transporters. However, little is known about the composition and regulation of the PIN protein complex. Here, using blue‐native PAGE and quantitative mass spectrometry, we identify native PIN core transport units as homo‐ and heteromers assembled from PIN1, PIN2, PIN3, PIN4 and PIN7 subunits only. Furthermore, we show that endogenous flavonols stabilize PIN dimers to regulate auxin efflux in the same way as does the auxin transport inhibitor 1‐naphthylphthalamic acid (NPA). This inhibitory mechanism is counteracted both by the natural auxin indole‐3‐acetic acid and by phosphomimetic amino acids introduced into the PIN1 cytoplasmic domain. Our results lend mechanistic insights into an endogenous control mechanism which regulates PIN function and opens the way for a deeper understanding of the protein environment and regulation of the polar auxin transport complex.     

Triton channels are sensitive to divalent cations and protons

Addition of Triton X-100 to planar bilayers composed of dioleoyl phosphatidyl choline, diphytanoyl phosphatidyl choline or mono-oleoyl glycerol induces single channel-like events when electrical conductivity across the bilayer is measured. Addition of divalent cations or protons causes channels to disappear; single channel conductance of remaining channels is not significantly altered; addition of EDTA or alkali (respectively) reverses the effect. It is concluded that sensitivity to divalent cations and protons need not be dependent on specific channel proteins or pore-forming toxins, but may be a feature of any aqueous pore across a lipid milieu.We are grateful to Dr. D.T. Edmonds and Prof. R.J.P. Williams for critical discussion, to Glenn Alder for technical assistance, to Ms. B. Bashford and Ms. S.G. Pelc for preparing the paper, and to the Cell Surface Research Fund, the Royal Society (A.A.L.), UNESCO (Molecular and Cell Biology Network) and The Wellcome Trust for financial support.     

Virus, toxin, complement: common actions and their prevention by Ca2+ or Zn2+

Membrane damage induced by haemolytic agents does not necessarily lead to lysis: the pores that are formed at low concentration of agent are formed at low concentration of agent are not large enough to allow leakage of cytoplasmic proteins, and in many instances the lesions become repaired with time. Quite different agents induce a similar type of lesion: in each case leakage is reduced at low ionic strenth, and is prevented by divalent cations such as Ca²⁺ or Zn²⁺, suggesting a possible therapeutic approach to the containment of several membrane-damaging diseases.     

Peripheral orphanin FQ/nociceptin analgesia in the mouse.

Orphanin FQ/Nociceptin (OFQ/N) administered peripherally was an effective analgesic in the tailflick test in mice (ED50 16.3 microg). It had a peak effect at 5 min and lasted up to 30 min. The kappa3 analgesic naloxone benzoylhydrazone was also active peripherally (ED50 3.8 microg). The analgesic actions of both agents were blocked by naloxone. Neither OFQ/N(1-11) nor OFQ/N(1-7) had appreciable peripheral activity. Antisense mapping both compounds against the murine orphan opioid receptor (KOR-3) confirmed the importance of this clone in their actions. Antisense probes targeting the second and third coding exons significantly lowered the analgesic effects of both compounds. However, the antisense targeting the first coding exon blocked only the actions of OFQ/N and not kappa3 analgesia.     

Lymphocyte culture supernatants prevent sickling of red blood cells

Metabisulphate-treated red blood cells from sickle-cell patients were protected from sickling by exposure to supernatants from cultures of phytohemagglutinin-stimulated normal human lymphocytes. Such supernatants, when not thus stimulated, afforded no protection.