RANTES, which is released from thrombin-stimulated platelets, is a member of the 8-kD cytokine family that has been shown to possess chemotactic activity for eosinophils. Thus, in this study, we examined the effect of RANTES on radical oxygen products from eosinophils. RANTES treatment resulted in the enhancement of peak value and intergrated value of productivity of eosinophil-mediated radical oxygen products determined by luminol-dependent chemiluminescence of EoL-3 cells stimulated with A23187. In addition, the radical oxygen products of EoL-1 or eosinophils showed similar results. Thus, we could conclude that platelets might play an important role in the pathogenesis of allergic inflammation through the involvement in the selective eosinophil infiltration and eosinophil activation by releasing RANTES.

KRAS mutations are detected in numerous human cancers, but there are few effective drugs for KRAS‐mutated cancers. Transporters for amino acids and glucose are highly expressed on cancer cells, possibly to maintain rapid cell growth and metabolism. Alanine‐serine‐cysteine transporter 2 (ASCT2) is a primary transporter for glutamine in cancer cells. In this study, we developed a novel monoclonal antibody (mAb) recognizing the extracellular domain of human ASCT2, and investigated whether ASCT2 can be a therapeutic target for KRAS‐mutated cancers. Rats were immunized with RH7777 rat hepatoma cells expressing human ASCT2 fused to green fluorescent protein (GFP). Splenocytes from the immunized rats were fused with P3X63Ag8.653 mouse myeloma cells, and selected and cloned hybridoma cells secreting Ab3‐8 mAb were established. This mAb reacted with RH7777 transfectants expressing ASCT2‐GFP proteins in a GFP intensity‐dependent manner. Ab3‐8 reacted with various human cancer cells, but not with non‐cancer breast epithelial cells or ASCT2‐knocked out HEK293 and SW1116 cells. In SW1116 and HCT116 human colon cancer cells with KRAS mutations, treatment with Ab3‐8 reduced intracellular glutamine transport, phosphorylation of AKT and ERK, and inhibited in vivo tumor growth of these cells in athymic mice. Inhibition of in vivo tumor growth by Ab3‐8 was not observed in HT29 colon and HeLa uterus cancer cells with wild‐type KRAS. These results suggest that ASCT2 is an excellent therapeutic target for KRAS‐mutated cancers.

Although many previous studies reported that honey promotes wound healing, no study has examined the effects of Japanese honey. The aim of this study was to investigate the effects of three types of Japanese honey, Acacia, Buckwheat flour, and Chinese milk vetch honey, on wound healing in comparison with hydrocolloid dressing. Circular full-thickness skin wounds were produced on male mice. Japanese honey or hydrocolloid dressing was applied daily to the mice for 14 days. The ratio of wound area for the hydrocolloid dressing group increased initially in the inflammatory and early proliferative phases and then decreased rapidly to heal with scarring. However, the ratios of wound area for the Japanese honey groups decreased in the inflammatory phase, increased in the proliferative phase, and decreased in the proliferative phase, and some wounds were not completely covered with new epithelium. These findings indicate that using Japanese honey alone has limited benefit, but since it reduces wound size in the inflammatory phase, it is possible to apply a combined treatment in which Japanese honey is applied only in the inflammatory phase, followed by hydrocolloid dressing from the proliferative phase, which would effectively contract the wound.

The effect of platelet-activating factor (PAF) and platelet factor 4 (PF4) on the adhesion of isolated human eosinophils or eosinophilic cell lines (EoL-1, EoL-3) was examined. Both PAF and PF4 augmented eosinophil adhesion to plates coated with AB plasma or recombinant soluble intercellular adhesion molecule-1 (r-sICAM-1). These findings suggest that PAF and PF4 not only modulate chemotactic activity of eosinophils but also intensify the function of eosinophil adhesion. Since PAF and PF4 induce the expression of adhesion molecules (LFA-1α, LFA-1β, CR3) on eosinophils, we could conclude that PAF or PF4 are closely related to eosinophil accumulation not only as chemotactic agents but also as augmentative agents for eosinophil adhesion through involvement in functional eosinophil adherence as well as surface expression of adhesion molecules on eosinophils.

Copyright: Okita et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License 3.0 (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. ABSTRACTResistance of progressive cancers against chemotherapy is a serious clinical problem. In this context, human epidermal growth factor receptor 3 (HER3) can play important roles in drug resistance to HER1-and HER2-targeted therapies. Since clinical testing of anti-HER3 monoclonal antibodies (mAbs) such as patritumab could not show remarkable effect compared with existing drugs, we generated novel mAbs against anti-HER3. Novel rat mAbs reacted with HEK293 cells expressing HER3, but not with cells expressing HER1, HER2 or HER4. Specificity of mAbs was substantiated by the loss of mAb binding with knockdown by siRNA and knockout of CRISPR/ Cas9-based genome-editing. Analyses of CDR sequence and germline segment have revealed that seven mAbs are classified to four groups, and the binding of patritumab was inhibited by one of seven mAbs. Seven mAbs have shown reactivity with various human epithelial cancer cells, strong internalization activity of cell-surface HER3, and inhibition of NRG1 binding, NRG1-dependent HER3 phosphorylation and cell growth. Anti-HER3 mAbs were also reactive with in vivo tumor tissues and cancer tissue-originated spheroid. Ab4 inhibited in vivo tumor growth of human colon cancer cells in nude mice. Present mAbs may be superior to existing anti-HER3 mAbs and support existing anti-cancer therapeutic mAbs.