A new bufadienolide from Bufo gargarizans Cantor.

Bufo gargarizans Cantor (B. gargarizans) is the most widely distributed and abundant species of toad in China. Bufadienolides and indole alkaloids have cardiotonic and anti-tumor activities and are important pharmacological components of B. bufo gargarizans. In this experiment, a novel compound (1) and two known compounds (2 and 3) were isolated and identified from the dry skin of B. bufo gargarizans, both of which are bufadienolides. Various column chromatography methods were used to separate and purify the extract from the dried skin of B. bufo gargarizans. Accurate molecular weights were measured by HR-ESI-MS, and the chemical structure of the compounds was determined by NMR spectrometers. The structures were named as (2ß,5ß,16α)-2,5,16-trihydroxide bufa-14,20,22 dienolide (1), gamabufotalin (2) and desacetylbufotalin (3). In vitro cytotoxic activity assay indicated that compound 1 showed a moderate cytotoxicity against A549 cells with IC50 value of 12.65 µM.

Targeting CD47 Inhibits Tumor Development and Increases Phagocytosis in Oral Squamous Cell Carcinoma.

BACKGROUND: Our previous work demonstrated upregulated CD47 in Oral Squamous Cell Carcinoma (OSCC). OBJECTIVE: In the present study, we aimed to investigate the effects of CD47 on tumor cell development and phagocytosis in OSCC and elucidate the underlying mechanisms. METHODS: The proliferation, apoptosis, migration, and invasion of oral cancer cells were analyzed after knocking down the expression of CD47. The effects of CD47 on tumor development were also evaluated using a murine model of OSCC. The involvement of CD47 in the phagocytosis of oral cancer cells was identified. RESULTS: Cell proliferation was suppressed by knocking down the expression of CD47 in human OSCC cell line Cal-27 cells but there was no change in the apoptosis rate. Moreover, impaired expression of CD47 inhibited the migration and invasion of Cal-27 cells. Furthermore, we found that nude mice injected with CD47 knockeddown Cal-27 cells displayed decreased tumor volumes at week 9 compared to xenograft transplantations of blank Cal-27 cells. In addition, in vitro phagocytosis of Cal-27 cells by macrophages was significantly enhanced after the knockdown of CD47, which positively correlated with compromised STAT3/JAK2 signaling. CONCLUSION: In summary, the knockdown of CD47 downregulated the development of OSCC and increased the phagocytosis of Cal-27 cells, indicating that CD47 might be a promising therapeutic target.

Icaritin Reduces Oral Squamous Cell Carcinoma Progression via the Inhibition of STAT3 Signaling.

Icaritin, a traditional Chinese medicine, possesses antitumor activity. The current study aimed to investigate icaritin effect and potential mechanism on oral squamous cell carcinoma (OSCC) development. OSCC cells proliferation, apoptosis, and autophagy were analyzed after incubation with icaritin at different concentrations and incubation times. The expressions of proteins related to proliferation, apoptosis, and autophagy, as well as signal transducer and activator of transcription 3 (STAT3) signal network, were also evaluated by western blot. Furthermore, STAT3 was knocked down by siRNA transfection to determine STAT3 role in OSCC cell proliferation and apoptosis. An oral specific carcinogenesis mouse model was used to explore icaritin effect on OSCC in vivo. Icaritin significantly inhibited OSCC proliferation in vitro and reduced the expression of both the cell-cycle progression proteins cyclin A2 and cyclin D1. Besides, icaritin increased cleaved caspase 3 and cleaved poly-(ADP-ribose) polymerase expression leading to apoptosis, and it activated autophagy. Icaritin significantly inhibited the expression of phospho-STAT3 (p-STAT3) in a dose- and time-dependent manner. In the in vivo experiment, the number of malignant tumors in the icaritin-treated group was significantly lower than the control. Overall, icaritin suppressed proliferation, promoted apoptosis and autophagy, and inhibited STAT3 signaling in OSCC in vitro and in vivo. In conclusion, icaritin might be a potential therapeutic agent against OSCC development.

TLR4-induced B7-H1 on keratinocytes negatively regulates CD4+ T cells and CD8+ T cells responses in oral lichen planus.

Oral lichen planus (OLP) is a T-cell-mediated autoimmune mucocutaneous disease affected by the interactions among the keratinocytes, CD4+ T cells and CD8+ T cells. B7-H1 induced by Toll-like receptors (TLRs) can suppress T-cell immune reaction, thereby resulting in immune tolerance. However, the role of TLR-mediated B7-H1 on keratinocytes in the immune response of OLP is still unknown. The present study showed that TLR4 could induce time-coursed B7-H1 expression on oral keratinocytes, and blocking NF-κB or PI3K/mTOR pathway downregulated B7-H1 transcriptional expression. Moreover, TLR4-stimulated oral keratinocytes inhibited the proliferation of OLP CD4+ T cells and OLP CD8+ T cells, and simultaneously prompted their apoptosis. Blockade of keratinocyte-associated B7-H1 restored the declined proliferation of OLP CD4+ T cells and OLP CD8+ T cells, and prevented their increased apoptosis. Therefore, TLR4-upregulated B7-H1 on keratinocytes could decelerate immune responses of CD4+ T cells and CD8+ T cells in OLP.