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Background/Aims: 2-O-methylmagnolol (MM1), a derivative of magnolol bearing one methoxy moiety, has been shown to display improved anti-tumor activity against skin cancers. In this study, we examined the anti-tumor effects of magnolol and MM1 on oral squamous cell carcinoma (OSCC). Methods: Trypane blue staining and clonogenic assays were performed to determine the cytotoxic effects of magnolol and MM1 in OSCC cells. Migration and matrigel invasion assays were carried out to examine the metastasis effects of magnolol and MM1 in OSCC cells. IL6-stimulation, Western blot, and immunohistochemistry were used to investigate the IL-6/STAT3 signaling and apoptosis. A bioluminescent mouse model of orthotopically implanted SAS cells was used to determine the anti-tumor activity of MM1 in vivo. Results: MM1 displays greater activity than magnolol on affecting the cytotoxicity, migration, and invasion of OSCC cells cultured in vitro. The improved anti-tumor activity of MM1 was shown to associate with its greater activity to inhibit STAT3 signaling and to induce apoptosis in the OSCC. In addition, we presented evidence that MM1 is effective in inhibiting the growth of orthotopic implanted OSCC cells in vivo. Conclusion: Our data indicate that MM1 displays greater anti-tumor activity than magnolol in OSCC and is an attractive agent to be further explored for its potential clinical application.

Background: MicroRNAs (miRNAs) are small, single-stranded, noncoding RNAs, which usually bind to the 3'-untranslated region of target mRNAs and are capable of inducing posttranscriptional gene regulation by blocking translation or by degrading the target mRNA. However, the expression level of miR-23 in radiation induced carcinogenesis is largely unknown. Methods: Radiation induced thymic lymphoma model in BALB/c mice was set up. miR-23a & miR-23b miRNA levels in different tissues and cells were detected by real-time qPCR. miR-23a/b inhibitor and miR-23a/b mimics were transfected to lymphoma cells and the target of miR-23a/b was identified by microRNA target prediction and Luciferase assays. Results: We found that miR-23a & miR-23b were up-regulated in radiation induced thymic lymphoma tissue samples. Cell death and apoptosis were increased by miR-23a/b inhibitor and decreased by miR-23a/b mimics in lymphoma cells. Computational analysis found a putative target site of miR-23a/b in the 3′UTR of Fas mRNA, which was verified by luciferase reporter assay. Forced over-expression of miR-23a/b decreased the level of Fas protein. Moreover, over-expression of Fas rescued the pro-proliferation effect of miR-23, indicating Fas is a direct mediator of miR-23 functions. Furthermore, contrast to miR-23a/b which was up regulated, the Fas expression level was down-regulated and inversely correlated with miR-23 in split radiation induced lymphoma tissue samples. Finally, our data also indicates that miR-23a could repress Fas much more potent than miR-23b and the additional region besides conserved seed pairing enables miR-23a's higher regulation. Conclusions: In this study, using a radiation induced thymic lymphoma model in BALB/c mice, We conclude that the expression of miR-23a/b is up-regulated in radiation-induced thymic lymphoma and it maybe a novel therapeutic target of that cancer.

Background: Exposure of high dose ionizing radiation is lethal. Signal pathways involved in radiation biology reaction still remain illdefined. Lipopolysaccharides (LPS), the ligands of Toll-like receptor 4(TLR4), could elicit strong immune responses. Glycogen synthase kinase-3β(GSK-3β) promotes the production of inflammatory molecules and cell migration. Inhibition of GSK-3β provides protection against inflammation in animal models. The aim of the study was to investigate role of GSK-3β in LPS shock and ionizing radiation. Methods: WT or IL-6-/-mice or cells were pretreated with SB216763, a GSK-3β inhibitor, and survival of the mice was determined. Cell viability was assayed by Cell Counting Kit. Apoptosis was assayed by Annexin V-PI double staining. Serum concentrations of IL-6 and TNF-α were determined by ELISA. Results: SB216763 attenuated LPS induced mice or cell death but aggravated radiation induced mice or cell death. SB216763 reduced IL-6, but not TNF-α levels in vivo. IL-6-/- mice were more resistant to LPS-induced death but less resistant to radiation-induced death than wild type mice. Conclusions: Inhibition of GSK-3β conferred resistance to LPS shock but fostered death induced by ionizing radiation. Inhibition of GSK-3β was effective by reducing IL-6.