JAK2 regulation by licochalcone H inhibits the cell growth and induces apoptosis in oral squamous cell carcinoma.

BACKGROUND: Licochalconce (LC) H is an artificial compound in the course of synthesizing LCC in 2013. So far, few studies on the effects of LCH have been found in the literature. Despite progress in treatment modalities for oral cancer, the cure from cancer has still limitations. PURPOSE: The effects of LCH were investigated on human oral squamous cell carcinoma (OSCC) cells to elucidate its mechanisms. STUDY DESIGN: We explored the mechanism of action of LCH by which it could have effects on JAK2/STAT3 signaling pathway. METHODS: To confirm LCH anti-cancer effect, analyzed were MTT assay, DAPI staining, soft agar, kinase assay, molecular docking simulation, flow cytometry and Western blotting analysis. RESULTS: According to docking and molecular dynamics simulations, the predicted pose of the complex LCH and JAK2 seems reasonable and LCH is strongly bound to active JAK2 with opened activation loop. The LCH inhibitor is surrounded by specific ATP-binding pocket in which it is stabilized by forming hydrogen bonds and hydrophobic interactions. It is shown that LCH plays as a competitive inhibitor in an active state of JAK2. LCH caused a dose-dependent decrease in phosphorylation of JAK2 and STAT3. More interestingly, LCH suppressed JAK2 kinase activity in vitro by its direct binding to the JAK2. LCH significantly inhibited the JAK2/STAT3 signaling pathway, causing the down-regulation of target genes such as Bcl-2, survivin, cyclin D1, p21 and p27. In addition, LCH inhibited cell proliferation and colony formation of OSCC cells in a dose- and time-dependent manner, as well as induction of cell apoptosis through extrinsic and intrinsic pathway. The induction of apoptosis in OSCC cells by LCH was evident in the increased production of ROS, loss of mitochondrial membrane potential, release of cyto c, variation of apoptotic proteins and activation of caspase cascade. CONCLUSION: LCH not only induces apoptosis in OSCC cells through the JAK/STAT3 signaling pathway but also inhibits cell growth. It is proposed that LCH has a promising use for the chemotherapeutic agent of oral cancer.

Design of a Novel and Selective IRAK4 Inhibitor Using Topological Water Network Analysis and Molecular Modeling Approaches.

Protein kinases are deeply involved in immune-related diseases and various cancers. They are a potential target for structure-based drug discovery, since the general structure and characteristics of kinase domains are relatively well-known. However, the ATP binding sites in protein kinases, which serve as target sites, are highly conserved, and thus it is difficult to develop selective kinase inhibitors. To resolve this problem, we performed molecular dynamics simulations on 26 kinases in the aqueous solution, and analyzed topological water networks (TWNs) in their ATP binding sites. Repositioning of a known kinase inhibitor in the ATP binding sites of kinases that exhibited a TWN similar to interleukin-1 receptor-associated kinase 4 (IRAK4) allowed us to identify a hit molecule. Another hit molecule was obtained from a commercial chemical library using pharmacophore-based virtual screening and molecular docking approaches. Pharmacophoric features of the hit molecules were hybridized to design a novel compound that inhibited IRAK4 at low nanomolar levels in the in vitro assay.

Licochalcone A, a natural chalconoid isolated from Glycyrrhiza inflata root, induces apoptosis via Sp1 and Sp1 regulatory proteins in oral squamous cell carcinoma.

Licochalcone A (LCA), a chalconoid derived from root of Glycyrrhiza inflata, has been known to possess a wide range of biological functions such as antitumor, anti-angiogenesis, antiparasitic, anti-oxidant, antibacterial and anti-inflammatory effects. However, the anticancer effects of LCA on oral squamous cell carcinoma (OSCC) have not been reported. Our data showed that LCA inhibited OSCC cell (HN22 and HSC4) growth in a concentration- and time-dependent manner. Mechanistically, it was mediated via downregulation of specificity protein 1 (Sp1) expression and subsequent regulation of Sp1 downstream proteins such as p27, p21, cyclin D1, Mcl-1 and survivin. Here, we found that LCA caused apoptotic cell death in HSC4 and HN22 cells, as characterized by sub-G1 population, nuclear condensation, Annexin V staining, and multi-caspase activity and apoptotic regulatory proteins such as Bax, Bid, Bcl(-xl), caspase-3 and PARP. Consequently, this study strongly suggests that LCA induces apoptotic cell death of OSCC cells via downregulation of Sp1 expression, prompting its potential use for the treatment of human OSCC.

Anti-proliferative effect of honokiol in oral squamous cancer through the regulation of specificity protein 1.

Honokiol (HK), a novel plant-derived natural product, is a physiologically activated compound with polyphenolic structure, and has been identified to function as an anticancer agent. It has been widely used in several diseases as a traditional medicine for a long time. We investigated whether HK could show anticancer effects on two oral squamous cell lines (OSCCs), HN-22 and HSC-4. We demonstrated that HK-treated cells showed dramatic reduction in cell growth and apoptotic cell morphologies. Intriguingly, the transcription factor specificity protein 1 (Sp1) was significantly inhibited by HK in a dose-dependent manner. Furthermore, we checked changes in cell cycle regulatory proteins and anti-apoptotic proteins at the molecular level, which are known as Sp1 target genes. The important key regulators in the cell cycle such as p27 and p21 were up-regulated by HK-mediated down-regulation of Sp1, whereas anti-apoptotic proteins including Mcl-1 and survivin were decreased, resulting in caspase-dependent apoptosis. Taken together, results from this study suggest that HK could modulate Sp1 transactivation and induce apoptotic cell death through the regulation of cell cycle and suppression of anti­apoptotic proteins. In addition, HK may be used in cancer prevention and therapies to improve the clinical outcome as an anticancer drug.

Therapeutic effect of total ginseng saponin on skin wound healing.

In this study, we investigated the effects of total ginseng saponin (TGS) on the cutaneous wound healing process using histological analysis. A total of 24 ICR mice, 5-weeks-old, were used for all in vivo experiments. Mice were divided into control and TGS-treated groups and four equidistant 1-cm full-thickness dorsal incisional wounds were created. The wounds were extracted at days 1, 3, 5, and 7 post-injury for histomorphometrical analysis including wound area and contracture measurements, keratinocyte migration rate, and calculation of infiltrating inflammatory cells. The results showed that the wound area was smaller and keratinocyte migration rate was higher in the TGS-treated group than that of the control group from days 3 to 7. Inflammatory cells in the TGS-treated group at days 1 and 3 were reduced compared to the control group. Wound contraction in the TGS-treated group was greater than in the control group on days 3 to 5, and collagen deposition in the TGS-treated group was higher than in the control group during wound healing. The results indicate a beneficial effect of TGS when used to treat skin wounds.

Design, synthesis, and evaluation of 2-aryl-7-(3',4'-dialkoxyphenyl)-pyrazolo[1,5-a]pyrimidines as novel PDE-4 inhibitors.

Described herein is design, synthesis, and biological evaluation of novel series of 2-aryl-7-(3',4'-dialkoxyphenyl)-pyrazolo[1,5-a]pyrimidines acting as inhibitors of type 4 phosphodiesterase (PDE4) which is known as a good target for the treatment of asthma and COPD. For this purpose, structure optimization was conducted with the aid of structure-based drug design using the known X-ray crystallography. Also, biological effects of these compounds on the target enzyme were evaluated by using in vitro assays, leading to the potent and selective PDE-4 inhibitor (IC(50)<10nM).

Cell-based assay for screening 11beta-hydroxysteroid dehydrogenase 1 inhibitors.

11beta-Hydroxysteroid dehydrogenase 1 (11beta-HSD1) is primarily responsible for intracellular biosynthesis of active glucocorticoid, and its tissue-specific dysregulation has been implicated in the development of metabolic syndromes. We have developed a cell-based assay for measuring 11beta-HSD1 activities using murine skeletal muscle cell line C2C12. We found that the messenger RNA (mRNA) expression of 11beta-HSD1 increased on differentiation with enhanced enzyme activity as determined by homogeneous time-resolved fluorescence (HTRF) assay. Carbenoxolone, a well-known 11beta-HSD1 inhibitor, exhibited an IC(50) value similar to that in in vitro microsomal assay (IC(50) = 0.3 microM). Unlike in vitro microsomal assay, cosubstrate NADPH was not required in the cell-based assay, indicating that viable cells might provide a sufficient amount of endogenous NADPH to catalyze the enzymatic conversion of inactive cortisone to active cortisol. Treatment of C2C12 myotubes with cortisone concentration dependently transactivated and transrepressed glutamine synthase and interleukin-6, respectively, which were abrogated by carbenoxolone or RU-486 (mifepristone), a glucocorticoid receptor antagonist. Accordingly, a newly designed cell-based assay using differentiated skeletal muscle cells would be useful for high-throughput screening of 11beta-HSD1 inhibitors as well as for understanding the molecular mechanisms of glucocorticoid action.