Interaction of Trastuzumab with biomembrane models at air-water interfaces mimicking cancer cell surfaces

Trastuzumab (Tmab) is a monoclonal antibody administered as targeted therapy for HER2-positive breast cancer whose molecular interactions at the HER2 receptor microenvironment are not completely clarified yet. This paper describes the influence of Tmab in the molecular organization of films of biological-relevant molecules at the air water interface. For that, we spread components of tumorigenic and non-tumorigenic cells directly on the air-water interface. The physicochemical properties of the films were investigated with surface pressure-area isotherms and Brewster angle microscopy, and distinction between the cellular lines with higher or lower amount of HER2 could be detected based on the physicochemical properties of the interfacial films. The systems organized at the air-water interface were transferred to solid supports as Langmuir-Blodgett films and the nano-scale morphology investigated with atomic force microscopy. The overall results related to Tmab interacting with the films lead to the conclusion that Tmab tends to condense rich-HER2 films, causing irregular dimerization of the receptor protein, changing the membrane topography of the films, with formation of phases with different levels of reflectivity and aggregation morphology, and finally revealing that the interaction of the antibody with proteo-lipidic biointerfaces is modulated by the film composition. We believe that novel perspectives concerning the molecular interactions in the plasma membrane microenvironment through Langmuir monolayers can be obtained from this work in order to enhance the Tmab-based cancer therapy.     

Thromboxane A2 receptor linked with the Ca2+ pathway in rat colonic crypt cells.

To clarify the presence of thromboxane A2 (TXA2) receptor in the colonic epithelium, we examined the effect of 9,11-epithio-11, 12-methano-thromboxane A2 (STA2), a stable analogue of TXA2, on intracellular free Ca2+ concentration ([Ca2+]i) of indo-1-loaded single cells in isolated rat colonic crypts by laser confocal microscopy. STA2 increased [Ca2+]i in a concentration-dependent manner with a transient peak phase and a subsequent plateau phase. The EC50 values at peak and plateau phases were 1 and 32 nM, respectively. The STA2-induced increase in [Ca2+]i was completely blocked by two selective TXA2 receptor antagonists, KW-3635 and ONO-3708. These antagonists did not affect both the basal [Ca2+]i and the carbaco-induced increase in [Ca2+]i. Prostaglandin E2 did not increase [Ca2+]i. These results indicate that the STA2-elicited increase in [Ca2+]i is mediated specifically by a TXA2 receptor in colonic crypt cells This is the first report showing the presence of a TXA2 receptor that is associated with Ca2+ mobilization in the colon.     

Orchidantha inouei (Lowiaceae), a new species from Borneo

A new species, Orchidantha inouei , is described from Sarawak. Two types of paracladium in the inflorescence are reported with a discussion on the inflorescence morphology of Lowiaceae.     

Reconstruction of Multiple Facial Nerve Branches Using Skeletal Muscle-Derived Multipotent Stem Cell Sheet-Pellet Transplantation

Head and neck cancer is often diagnosed at advanced stages, and surgical resection with wide margins is generally indicated, despite this treatment being associated with poor postoperative quality of life (QOL). We have previously reported on the therapeutic effects of skeletal muscle-derived multipotent stem cells (Sk-MSCs), which exert reconstitution capacity for muscle-nerve-blood vessel units. Recently, we further developed a 3D patch-transplantation system using Sk-MSC sheet-pellets. The aim of this study is the application of the 3D Sk-MSC transplantation system to the reconstitution of facial complex nerve-vascular networks after severe damage. Mouse experiments were performed for histological analysis and rats were used for functional examinations. The Sk-MSC sheet-pellets were prepared from GFP-Tg mice and SD rats, and were transplanted into the facial resection model (ST). Culture medium was transplanted as a control (NT). In the mouse experiment, facial-nerve-palsy (FNP) scoring was performed weekly during the recovery period, and immunohistochemistry was used for the evaluation of histological recovery after 8 weeks. In rats, contractility of facial muscles was measured via electrical stimulation of facial nerves root, as the marker of total functional recovery at 8 weeks after transplantation. The ST-group showed significantly higher FNP (about three fold) scores when compared to the NT-group after 2–8 weeks. Similarly, significant functional recovery of whisker movement muscles was confirmed in the ST-group at 8 weeks after transplantation. In addition, engrafted GFP⁺ cells formed complex branches of nerve-vascular networks, with differentiation into Schwann cells and perineurial/endoneurial cells, as well as vascular endothelial and smooth muscle cells. Thus, Sk-MSC sheet-pellet transplantation is potentially useful for functional reconstitution therapy of large defects in facial nerve-vascular networks.     

Clock,love and memory: Circadian and non-circadian regulation of Drosophila mating behavior by clock genes

Sleep and Biological Rhythms - Mating behavior is arguably the most important and fundamental behavior in animals. In the fruit fly, Drosophila melanogaster, both experience-dependent and...     

A Method of Determination of Penta-, Tetra-, Tri-, and Disaccharides from Xylan by Ion-exchange Chromatography

Bacillus subtilis B7, a tmrA mutant, shows both tunicamycin resistance and a-amylase hyperproductivity. The tmrA characters can be transferred simultaneously to recipient cells by DNA-mediated transformation. We found a typical gene amplification phenomenon in the tmrA transformants and B7 strain. The amplified unit, 16.3kb in size, covers a-amylase structural gene amyE to another tunicamycin resistance gene tmrB, which is located 9kb downstream of the amyE gene. About 10 repeating units are supposed to be tandemly repeated in the transformants. Amplification of the wild amyE and tmrB genes could be the cause of the α-amylase hyperproductivity and tunicamycin resistance of the tmrA transformants and B7 strain.     

Anti-epidermal growth factor antibody inhibits compensatory renal hyperplasia but not hypertrophy after unilateral nephrectomy in mice.

The effect of anti-epidermal growth factor (EGF) antibody on the compensatory renal growth including hyperplasia and hypertrophy was investigated. The antibody used in this study blocked the stimulatory effect of EGF on the DNA synthesis of cultured rat hepatocytes. When this antibody was injected into mice intravenously after unilateral nephrectomy, the labeling index of the renal cortical tubular cells decreased significantly at the second day after uninephrectomy, but the antibody caused no decrease in remaining kidney weight. Immunohistochemical study revealed that injected anti-mouse EGF rabbit IgG was positively stained at the renal cortical tubular cells. EGF would thus appear importantly essential to compensatory renal hyperplasia.     

Fecal microbiota transplantation prevents Candida albicans from colonizing the gastrointestinal tract

Gut microbes symbiotically colonize the gastrointestinal (GI) tract, interacting with each other and their host to maintain GI tract homeostasis. Recent reports have shown that gut microbes help protect the gut from colonization by pathogenic microbes. Here, we report that commensal microbes prevent colonization of the GI tract by the pathogenic fungus, Candida albicans. Wild‐type specific pathogen‐free (SPF) mice are resistant to C. albicans colonization of the GI tract. However, administering certain antibiotics to SPF mice enables C. albicans colonization. Quantitative kinetics of commensal bacteria are inversely correlated with the number of C. albicans in the gut. Here, we provide further evidence that transplantation of fecal microbiota is effective in preventing Candida colonization of the GI tract. These data demonstrate the importance of commensal bacteria as a barrier for the GI tract surface and highlight the potential clinical applications of commensal bacteria in preventing pathogenic fungal infections.     

Inhibition of the interactions of cofilin, destrin, and deoxyribonuclease I with actin by phosphoinositides

Cofilin is a widely distributed actin-modulating protein that has the ability to bind along the side of F-actin and to depolymerize F-actin in a pH-dependent manner. We found that phosphatidylinositol (PI), phosphatidylinositol 4-monophosphate (PIP), and phosphatidylinositol 4,5-bisphosphate (PIP2) inhibited both actions of cofilin in a dose-dependent manner, while inositol 1,4,5-triphosphate (IP3), 1-oleoyl-2-acetylglycerol (OAG), phosphatidylserine (PS), or phosphatidylcholine (PC) had little or no effect on them. Gel filtration analyses showed that PIP2 bound to cofilin and thereby inhibited the binding of cofilin to G-actin. Destrin is a mammalian, pH-independent actin-depolymerizing protein. The actin-depolymerizing activity of destrin was also inhibited by PI, PIP, and PIP2, but not by IP3, OAG, PS, or PC. In addition, we found further that an actin-depolymerizing activity of bovine pancreas deoxyribonuclease I, a G-actin-sequestering protein, was inhibited by PIP and PIP2, but not by PI, IP3, OAG, PS, or PC. These results together with previous findings (Lassing, I., and Lindberg, U. (1985) Nature 314, 472-474; Janmey, P. A., and Stossel, T. P. (1987) Nature 325, 362-364) suggest that the sensitivity to polyphosphoinositides may be a common feature in vitro among actin-binding proteins that can bind to G-actin and regulate the state of actin polymerization.     

The Dual RAF/MEK Inhibitor CH5126766/RO5126766 May Be a Potential Therapy for RAS-Mutated Tumor Cells

Although melanoma is the most aggressive skin cancer, recent advances in BRAF and/or MEK inhibitors against BRAF-mutated melanoma have improved survival rates. Despite these advances, a treatment strategy targeting NRAS-mutated melanoma has not yet been elucidated. We discovered CH5126766/RO5126766 as a potent and selective dual RAF/MEK inhibitor currently under early clinical trials. We examined the activity of CH5126766/RO5126766 in a panel of malignant tumor cell lines including melanoma with a BRAF or NRAS mutation. Eight cell lines including melanoma were assessed for their sensitivity to the BRAF, MEK, or RAF/MEK inhibitor using in vitro growth assays. CH5126766/RO5126766 induced G1 cell cycle arrest in two melanoma cell lines with the BRAF V600E or NRAS mutation. In these cells, the G1 cell cycle arrest was accompanied by up-regulation of the cyclin-dependent kinase inhibitor p27 and down-regulation of cyclinD1. CH5126766/RO5126766 was more effective at reducing colony formation than a MEK inhibitor in NRAS- or KRAS-mutated cells. In the RAS-mutated cells, CH5126766/RO5126766 suppressed the MEK reactivation caused by a MEK inhibitor. In addition, CH5126766/RO5126766 suppressed the tumor growth in SK-MEL-2 xenograft model. The present study indicates that CH5126766/RO5126766 is an attractive RAF/MEK inhibitor in RAS-mutated malignant tumor cells including melanoma.