Wogonoside inhibits tumor growth and metastasis in endometrial cancer via ER stress-Hippo signaling axis.

Wogonoside, a bioactive flavonoid component derived from Scutellaria baicalensis Georgi, has been reported to inhibit tumor growth in mice bearing various types of cancer cells such as breast cancer, lung cancer, and leukemia cells. However, whether wogonoside could inhibit tumor growth of endometrial cancer has not been elucidated. In this study, we explored the function of wogonoside on tumor growth and the underlying mechanism on endometrial cancer. Firstly, we investigated the effect of wogonoside on endometrial cancer cells and found that wogonoside could significantly decrease cell proliferation and metastasis. Mechanistically, wogonoside could aggravate the extent of ER stress and upregulate the phosphorylation level of Mammalian Ste20-like kinase 1, leading to the activation of the Hippo signaling pathway. Taken together, in vitro and in vivo data demonstrated that wogonoside could be a potent inducer of ER stress and could be further developed into a promising therapy for endometrial cancer.

Cell-density-dependent manifestation of partial characteristics for neuronal precursors in a newly established human gliosarcoma cell line.

Gliosarcoma cell line K308 was established from a primary tumor specimen removed from a 51-year-old male Han Chinese patient. Besides the typical characteristics of gliosarcoma cells, K308 cells express abundant glutaminase and can release large amount of glutamate. K308 exhibited cell-density-dependent expression of neuronal precursor markers, particularly nestin. At low density, the majority of K308 cells were nestin negative (approximately 70%) and nestin levels remained homogenous within each single-cell-derived colony when K308 proliferated. After reaching confluence, however, the majority of K308 cells turned nestin positive. These confluent K308 cells were also Sox2 positive and could form tumor spheres even in serum-containing media.

Glutamate/glutamine metabolism coupling between astrocytes and glioma cells: neuroprotection and inhibition of glioma growth.

Glioma glutamate release has been shown to promote the growth of glioma cells and induce neuronal injuries from epilepsy to neuronal death. However, potential counteractions from normal astrocytes against glioma glutamate release have not been fully evaluated. In this study, we investigated the glutamate/glutamine cycling between glioma cells and astrocytes and their impact on neuronal function. Co-cultures of glioma cells with astrocytes (CGA) in direct contact were established under different mix ratio of astrocyte/glioma. Culture medium conditioned in these CGAs were sampled for HPLC measurement, for neuronal ratiometric calcium imaging, and for neuronal survival assay. We found: (1) High levels of glutaminase expression in glioma cells, but not in astrocytes, glutaminase enables glioma cells to release large amount of glutamate in the presence of glutamine. (2) Glutamate levels in CGAs were directly determined by the astrocyte/glioma ratios, indicating a balance between glioma glutamate release and astrocyte glutamate uptake. (3) Culture media from CGAs of higher glioma/astrocyte ratios induced stronger neuronal Ca(2+) response and more severe neuronal death. (4) Co-culturing with astrocytes significantly reduced the growth rate of glioma cells. These results indicate that normal astrocytes in the brain play pivotal roles in glioma growth inhibition and in reducing neuronal injuries from glioma glutamate release. However, as tumor growth, the protective role of astrocytes gradually succumb to glioma cells.