Chemokine-chemokine receptor pathway as a tumor therapeutic target: the significance of SDF-1CXCR4 pair

Chemokines, a large family of chemotactic cytokines, are the major regulators of immune cell trafficking. The chemokine stromal cell-derived factor-1 (SDF-1, or CXCL12) and its cognate receptor, CXCR4 (CD184), are an important ligand-receptor pair, which play a crucial role in numerous biological processes including hematopoiesis, inflammation, angiogenesis, and cell proliferation. Moreover, accumulating evidence indicates that SDF-1-CXCR4 pair plays important roles in regulating processes essential for tumor biology. Molecular strategies aimed at inhibiting the SDF-1-CXCR4 pathway, such as small peptide CXCR4-specific antagonists, anti-CXCR4 antibodies, and small interfering RNA might therefore prevent tumor progression and metastasis. In the present Dance Round, we focus on (i) the role of the SDF-1-CXCR4 signaling in the regulation of tumor spread, growth, and vascularization, and (ii) the significance of this ligand-receptor pair as a novel therapeutic target for neoplastic disease.Biomedical Reviews 2005; 16: 77-81

Dynamic Evolution of S0_0∼\simS3_3 at the Oxygen Evolving Complex with the Spin Marker under the Photoelectric Polarization

Water oxidation in the oxygen evolving complex (OEC) of the photosystem II is catalyzed by the core cluster CaMn$_4$O$_5$ which was projected to experience five intermediate states S($\rm_i$) in the Kok's cycle since 1970's. However, the detailed dynamics of state evolutions still remains unclear, albeit with the general fact that the process is initiated by the transfer of photoelectrons with the steady electron donors of the water molecules. Based on density functional simulations, we find that the spin flips of Manganese atoms between the consecutive states in the electric polarization field can be used as a marker to uncover the intricate dynamic evolutions and the underlying dynamics. The dynamic electron and proton transfers and water insertion and dissociation are traced to reveal the evolution pathways of S$_0$$\sim$S$_3$ with commensurate spin flips towards the exact spin configuration of the next state. In particular, the various water insertions and dissociations at coordination sites of the S$_2$ open and closed cubane isomers are predicted with constraints on the necessary spin flips. Our study lays a solid ground for getting through the whole Kok's cycle via the pending S$_4$ state that is crucial for dioxygen generation.Comment: 8 pages, 5 figure

Generalized Shen-Larsson bifunctors and cohomologies of crossed homomorphisms

Using crossed homomorphisms, we show that the category of weak representations (resp. admissible representations) of Lie-Rinehart algebras (resp. Leibniz pairs) is a left module category over the monoidal category of representations of Lie algebras. In particular, the corresponding bifunctor which we call the generalized Shen-Larsson bifunctor is established to give new weak representations (resp. admissible representations) of Lie-Rinehart algebras (resp. Leibniz pairs). This generalizes and unifies various existing constructions of representations of many Lie algebras conceptually to evolve into one bifunctor. We construct some crossed homomorphisms in different situations and use our generalized Shen-Larsson bifunctors to recover some known constructions of representations of various Lie algebras, also to obtain new representations for generalized Witt algebras and their Lie subalgebras. The cohomology theory of crossed homomorphisms between Lie algebras is introduced and used to study linear deformations of crossed homomorphisms.Comment: 30 page