CD44s Induces miR-629-3p Expression in Association with Cisplatin Resistance in Head and Neck Cancer Cells.

Cisplatin (cis-diamminedichloroplatinum II [CDDP] ) is a well-known chemotherapeutic drug that has been used for the treatment of various types of human cancers, including head and neck cancer. Cisplatin exerts anticancer effects by causing DNA damage, replication defects, transcriptional inhibition, cell cycle arrest, and the induction of apoptosis. However, drug resistance is one of the most serious problems with cancer chemotherapy, and it causes expected therapeutic effects to not always be achieved. Here, we analyzed global microRNA (miRNA) expression in CD44 standard form (CD44s)-expressing SAS cells, and we identified miR-629-3p as being responsible for acquiring anticancer drug resistance in head and neck cancer. The introduction of miR-629-3p expression inhibited apoptotic cell death under cisplatin treatment conditions, and it promoted cell migration. Among the computationally predicted target genes of miR-629-3p, we found that a number of gene expressions were suppressed by the transfection with miR-629-3p. Using a xenografting model, we showed that miR-629-3p conferred cisplatin resistance to SAS cells. Clinically, increased miR-629-3p expression tended to be associated with decreased survival in head and neck cancer patients. In conclusion, our data suggest that the increased expression of miR-629-3p provides a mechanism of cisplatin resistance in head and neck cancer and may serve as a therapeutic target to reverse chemotherapy resistance.

The Core Fucose on an IgG Antibody is an Endogenous Ligand of Dectin-1.

The core fucose, a major modification of N-glycans, is implicated in immune regulation, such as the attenuation of the antibody-dependent cell-mediated cytotoxicity of antibody drugs and the inhibition of anti-tumor responses via the promotion of PD-1 expression on T cells. Although the core fucose regulates many biological processes, no core fucose recognition molecule has been identified in mammals. Herein, we report that Dectin-1, a known anti-ß-glucan lectin, recognizes the core fucose on IgG antibodies. A combination of biophysical experiments further suggested that Dectin-1 recognizes aromatic amino acids adjacent to the N-terminal asparagine at the glycosylation site as well as the core fucose. Thus, Dectin-1 appears to be the first lectin-like molecule involved in the heterovalent and specific recognition of characteristic N-glycans on antibodies.

Convergent Synthesis of a Bisecting N-Acetylglucosamine (GlcNAc)-Containing N-Glycan.

The chemical synthesis of a bisecting N-acetylglucosamine (GlcNAc)-containing N-glycan was achieved by a convergent synthetic route through [4+2] and [6+2] glycosylations. This synthetic route reduced the number of reaction steps, although the key glycosylations were challenging in terms of yields and selectivities owing to steric hindrance at the glycosylation site and a lack of neighboring group participation. The yields of these glycosylations were enhanced by stabilizing the oxocarbenium ion intermediate through ether coordination. Glycosyl donor protecting groups were explored in an effort to realize perfect α selectivity by manipulating remote participation. The simultaneous glycosylations of a tetrasaccharide with two disaccharides was investigated to efficiently construct a bisecting GlcNAc-containing N-glycan.

Chemical Synthesis of a Complex-Type N-Glycan Containing a Core Fucose.

A chemical synthesis of a core fucose containing N-glycan was achieved. Asparagine was introduced at an early stage of the synthesis, and the sugar chain was convergently elongated. As for the fragment synthesis, we reinvestigated α-sialylation, ß-mannosylation, and N-glycosylation to reveal that precise temperature control was essential for these glycosylations. Intermolecular hydrogen bonds involving acetamide groups were found to reduce the reactivity in glycosylations: the protection of NHAc as NAc2 dramatically improved the reactivity. The dodecasaccharide-asparagine framework was constructed via the (4 + 4) glycosylation and the (4 + 8) glycosylation using the tetrasaccharide donor and the tetrasaccharide-asparagine acceptor. An ether-type solvent enhanced the yields of these key glycosylations between large substrates. After the whole deprotection of the dodecasaccharide, the target N-glycan was obtained.

Clinicopathological implications of vascular endothelial growth factor 165b expression in oral squamous cell carcinoma stroma.

Vascular endothelial growth factor (VEGF) is one of the most important angiogenic factors. VEGF165b was recently isolated as the anti-angiogenic VEGF splice variant. In the present study, we examined the association between VEGF165b expression and clinicopathological characteristics in order to determine how VEGF165b produced from oral squamous cell carcinoma (OSCC) affects the stromal cell biological activity. We examined the relationships between the expressions of both VEGF isoforms in normal human dermal fibroblasts (NHDFs) and OSCC cell lines (HSC2, 3, 4 and SAS). Our analyses indicated that both the mRNA and protein expression levels of VEGF165b in the HSC2 and SAS cells were higher than those in the NHDFs. VEGF165b did not promote cell growth or invasive capabilities, but it induced the cell adhesive capabilities to ECM. Although strong expression of the VEGF165 isoforms in tumor cells of OSCC tissues was observed, there was no significant difference in the VEGF165b expression level among the various degrees of malignancy. OSCC cells secrete VEGF165b into the stroma, and this factor may contribute to the process of anti-angiogenesis by inhibiting gelatinase-expressing cells and activating cell adhesive capabilities to ECM, such as that of fibroblasts surrounding tumor cells.

A Combination of Low-Intensity Pulsed Ultrasound and Nanohydroxyapatite Concordantly Enhances Osteogenesis of Adipose-Derived Stem Cells From Buccal Fat Pad.

The osteogenic induction of adipose-derived stem cells (ADSCs) has been regarded as an important step in bone tissue engineering. In the present study, we focused on the buccal fat pad (BFP) as a source of adipose tissue, since BFPs are encapsulated by adipose tissue and are often coextirpated during oral surgery. Low-intensity pulsed ultrasound (LIPUS) is effective in the treatment of fractures, and nanohydroxyapatite (NHA) is known as a bone substitute material. Here we investigated the synergistic effects of LIPUS and NHA in the osteogenesis of ADSCs. A combination of LIPUS irritation and NHA as a scaffold significantly increased the osteogenic differentiation of ADSCs in vitro, and in our in vivo study in which ADSCs were transplanted into calvarial bone defects of nude mice, the combinational effect greatly enhanced the new bone formation of the margin of the defects. These results demonstrate that synergistic effects of LIPUS and NHA are capable of effectively inducing the differentiation of ADSCs into osteoblasts, and they suggest a novel therapeutic strategy for bone regeneration by the autotransplantation of ADSCs.

Revisiting the bromination of C-H bonds with molecular bromine by using a photo-microflow system.

The photobromination of C-H bonds by using molecular bromine was reinvestigated under microfluidic conditions. The continuous-flow method suppressed the production of dibrominated compounds and effectively produced the desired monobrominated products with high selectivity. Rapid bromination of benzylic substrates containing a photoaffinity azide group was achieved without any decomposition.

Reinvestigation of the C5-acetamide sialic acid donor for α-selective sialylation: practical procedure under microfluidic conditions.

Despite the previous literature describing the "low-to-modest" efficiency, the readily available C5-acetamide donor was reinvestigated for its use in α-sialylation under microfluidic conditions. The N-phenyltrifluoroacetimidate donor was efficiently mixed with an appropriate amount of TMSOTf to produce the α(2-6) and α(2-3)-sialylation products of galactose and glucosamine acceptors in excellent yields and with nearly perfect α-selectivity.