Cordycepin attenuates migration and invasion of HSC-4 oral squamous carcinoma cells through autophagy-dependent FAK/Akt and MMP2/MMP9 suppression.

Background/purpose: Cordycepin has been proposed anti-cancer effects, however, it is unclear whether and how cordycepin affects oral squamous carcinoma cell (OSCC) migration and invasion. This study aimed to investigate the effect of cordycepin on migration and invasion of OSCC (HSC-4 cells), and its underlying mechanism. Materials and methods: Cell viability was measured with MTT assay. Migrative and invasive abilities were determined by scratch wound healing, agarose spot and transwell invasion assays, respectively. Monodasylcadaverine (MDC) staining, immunofluorescence staining of LC3 and RT-PCR evaluated the gene expression of LC3 and p62 were applied to investigate autophagy. MMP2 and MMP9 gene expression and activity were examined by RT-PCR and gelatin zymography. Expression of caspase 3, cleaved caspase 3, FAK, p-FAK, Akt and p-Akt was determined by Western blot. Results: Cordycepin significantly inhibited HSC-4 cell migration and invasion in a concentration-dependent manner. Cordycepin treatment caused an induction of autophagy, as evidenced by increased MDC fluorescence intensity and MDC positive cells, and upregulated expression level of LC3 gene. In addition, inhibition of autophagy by chloroquine (CQ) significantly abolished cordycepin-inhibited HSC-4 cell migration and invasion, demonstrating that cordycepin-inhibited migration and invasion was mediated by autophagy. Mechanistic studies showed that cordycepin significantly suppressed FAK and Akt phosphorylation, and MMP2 and MMP9 activities. Conversely, CQ pre-incubation significantly restored its expression and activity in cordycepin-treated cells. Conclusion: Cordycepin induces autophagy to suppress FAK and Akt phosphorylation, and MMP2 and MMP9 activity, which responsible for the attenuation of HSC-4 cell migration and invasion.

Very high gravity ethanol fermentation from sweet sorghum stem juice using a stirred tank bioreactor coupled with a column bioreactor.

A stirred tank bioreactor (STR) coupled with two column bioreactors (CRs) was used for ethanol production from sweet sorghum stem juice by Saccharomyces cerevisiae SSJ01KKU in a very high gravity fermentation. The effects of the medium circulation rate between the STR and CRs (2.6 and 5.2 mL/min, corresponding to 25 and 50 % of the S. cerevisiae specific growth rate), the starting time of medium circulation (0 and 4 h) and cell inoculation were investigated. The results showed that a medium circulation rate of 5.2 mL/min, starting the medium circulation at the beginning of fermentation (0 h) with cell inoculation into the STR only were appropriate conditions for ethanol production. This yielded an average ethanol concentration (PE) of 120.96 g/L and ethanol productivity (QP) of 2.52 g/L⋅h. When a repeated-batch (RB) ethanol fermentation in the STR coupled with CR was carried out using a drain and fill technique at different volumes (75 and 90 %, referenced as RB1 and RB2, respectively), it was found that at least eight successive cycles could be operated under both RB1 and RB2. The average PE and QP for RB1 and RB2 were not significantly different. However, the average total ethanol production rate in RB2 (3.25 g/h) over the eight cycles was significantly higher than that of RB1 (2.60 g/h).