Induction of immunogenic cell death of tumors by newly synthesized heterocyclic quinone derivative

Many cancer types are serious diseases causing mortality, and new therapeutics with improved efficacy and safety are required. Immuno-(cell)-therapy is considered as one of the promising therapeutic strategies for curing intractable cancer. In this study, we tested R2016, a newly developed heterocyclic quinone derivative, for induction of immunogenic tumor cell death and as a possible novel immunochemotherapeutic. We studied the anti-cancer effects of R2016 against LLC, a lung cancer cell line and B16F10, a melanoma cell line. LLC (non-immunogenic) and B16F10 (immunogenic) cells were killed by R2016 in dose-dependent manner. R2016 reduced the viability of both LLC and B16F10 tumor cells by inducing apoptosis and necrosis, while it demonstrated no cytotoxicity against normal splenocytes. Expression of immunogenic death markers on the cell surface of R2016 treated tumor cells including calreticulin (CRT) and heat shock proteins (HSPs) was increased along with the induction of their genes. Increased CRT expression correlated with dendritic cell (DC) uptake of dying tumor cells: the proportion of CRT⁺CD11c⁺cells was increased in the R2016-treated group. The gene transcription of Calr3, Hspb1, and Tnfaip6, which are related to immunogenicity induction of dead cells, was up-regulated in the R2016 treated tumor cells. On the other hand, ANGPT1, FGF7, and URGCP gene levels were down-regulated by R2016 treatment. This data suggests that R2016 induced immunogenic tumor cell death, and suggests R2016 as an effective anti-tumor immunochemotherapeutic modality.

Spin waves and revised crystal structure of honeycomb iridate Na2IrO3

We report inelastic neutron scattering measurements on Na2IrO3, a candidate for the Kitaev spin model on the honeycomb lattice. We observe spin-wave excitations below 5 meV with a dispersion that can be accounted for by including substantial further-neighbor exchanges that stabilize zigzag magnetic order. The onset of long-range magnetic order below T(N)=15.3  K is confirmed via the observation of oscillations in zero-field muon-spin rotation experiments. Combining single-crystal diffraction and density functional calculations we propose a revised crystal structure model with significant departures from the ideal 90° Ir-O-Ir bonds required for dominant Kitaev exchange.

Reorganization of horizontal cell processes in the developing FVB/N mouse retina

We investigated the morphological changes of horizontal cells after postnatal photoreceptor degeneration in the developing FVB/N mouse retina, using immunocytochemistry with anti-calbindin D-28K. From postnatal day 14 (P14) onwards, processes emerging from horizontal cells descend into the inner plexiform layer (IPL) and ramify mainly in stratum 1 of the IPL. Electron microscopy revealed that the descending processes make synaptic contacts with bipolar cells in the outer plexiform layer. Our results clearly demonstrate that loss of photoreceptor cells induces the reorganization of horizontal cell processes in the retinas of FVB/N mice as they mature.

Genomic cloning and characterization of mitochondrial elongation factor Tu (EF-Tu) gene (tufM) from maize (Zea mays L.)

We have cloned and characterized a mitochondrial elongation factor Tu (EF-Tu) gene (tufM) in maize (Zea mays L.). This maize tufM gene encoded a polypeptide of 452 amino acid residues, consisting of a putative transit peptide of 55 residues and a mature EF-Tu of 397 residues. The coding region was composed of 12 exons and 11 introns that ranged from 76 to 1673bp in length. The deduced amino acid sequence showed 85.9% and 61.2% identity with Arabidopsis mitochondrial EF-Tu and Arabidopsis chloroplast EF-Tu sequence respectively. The transcription initiation site was determined to be 165bp upstream of the AUG initiation codon by primer extension analysis. Southern blot analysis revealed that the cloned EF-Tu gene was encoded by the members of small gene family in maize. Although this gene does not resemble the Arabidopsis nuclear tufA gene, which encodes the plastid EF-Tu, and does not contain sequence elements found in all cyanobacterial and plastid tufA genes, the predicted amino acid sequence includes an N-terminal extension that resembles a mitochondrial targeting sequence, and shares three unique sequence elements with mitochondrial EF-Tu's from Arabidopsis thaliana, Saccharomyces cerevisiae, and Homo sapiens. Therefore, we concluded that this gene encodes the maize mitochondrial EF-Tu.