Antitumor Effect of Periplocin in TRAIL-Resistant gastric cancer cells via upregulation of death receptor through activating ERK1/2-EGR1 pathway.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a member of the tumor necrosis factor family, induces apoptosis in a variety of cancer cells. However, gastric cancer (GC) cells are insensitive to TRAIL usually. In the previous study, we showed that Periplocin could induce apoptosis in GC cells via the activation of ERK1/2-EGR1 pathway. In the present study, we have shown that the combination of Periplocin and TRAIL had a greater inhibitory effect on gastric cancer cell viability in vitro and in vivo than Periplocin or TRAIL alone. Through upregulating the expression of DR4 and DR5 at transcriptional and protein levels, Periplocin enhanced the sensitivity of gastric cancer cells to TRAIL. Furthermore, enhanced activity of ERK1/2-EGR1 pathway was responsible for upregulating of DR4 and DR5 uponPeriplocin treatment, subsequently reducing the expression of Mcl-1 and Bcl2 and activating Bid and caspase-3/8. Collectively, these data implied that Periplocin might act as a sensitizer of TRAIL and could be a potential strategy for the treatment of GC.

Cystathionine ß-synthase expression correlates with tumor development and poor prognosis in patients with adenocarcinoma of the gastroesophageal junction.

OBJECTIVES: To reveal the expression level of cystathionine ß-synthase (CBS) in adenocarcinoma of esophagogastric junction (AEG) and discuss the relationship between CBS expression level and tumor microvascular density (MVD), clinical features and prognosis. METHODS: Paraffin samples from 214 patients with AEG were selected to make pathological microchips. Immunohistochemistry was performed based on the microchips to detect the expression level of CBS and microvascular density (MVD) in cancer tissues and adjacent control tissues. Relationships between expression level of CBS and MVD, clinical characteristics and prognosis were analyzed. RESULTS: In total, 214 AEG cases were classified into three groups: CBS negative staining (n=26), low staining (n=44), and high staining (n=144). Quantitative alterations in CBS and CD31 expression were explored using immunohistochemistry. The 5-year recurrence rate of enrolled patients was followed up and found that CBS expression was significantly increased in tumor tissue compared with adjacent non-tumor tissue (P<0.0001). There were significant differences in microvascular density between the groups with negative and high CBS staining (P<0.0001), and between the groups with low and high CBS staining (P<0.0001). Univariate analysis revealed significant differences in tumor stage (P<0.0001), T stage (P=0.008), N stage (P=0.028), differentiation degree (P=0.037), and 5-year survival (P=0.0034) among the three groups. Multivariate logic regression analysis showed that increased CBS scores were associated with an increased probability of 5-year recurrence (P=0.018). Finally, different CBS expression levels were associated with disease-free survival in AEG patients. CONCLUSIONS: CBS expression level is closely related to microvascular density and tumor stage in AEG. High level of CBS not only accelerates tumor angiogenesis but also affects patient's survival and prognosis.

Effect of overexpression of hypoxia-inducible factor-1α induced by hyperoxia in vivo in LNCaP tumors on tumor growth rate.

OBJECTIVE: To study effect of overexpression of hypoxia-inducible factor-1α induced by hyperoxia in vivo in LNCaP tumors on tumor growth rate. METHODS: The prostate cancer LNCaP cells were inoculated in the abdomen of mice. All the mice were randomly placed in the gas chamber with different oxygen content. The groups were divided as follows: twelve mice in hypoxia group, sixteen mice in normoxia group, ten mice in hyperoxia group. After 28 d of treatment, the mice were weighed, the blood samples were taken from the left ventricle, and the tumor was isolated and weighed. Tumor growth, angiogenesis and vascularization, HIF-1α expression and intracellular signal transduction molecules expression in each group of xenografts were detected and analyzed by using Western blotting and immunofluorescence and determination of hemoglobin. RESULTS: Comparison of the growth of xenografts in each group showed that, the xenografts growth of hypoxia group was more quickly than that of normoxia group. The difference was statistically significant (P = 0.004). The difference in xenografts growth between hyperoxia group compared and normoxia group was not statistically significant (P > 0.05). The expressions of HIF-1α, VEGF and VEGF-R of xenografts in hyperoxia group were significantly higher than those of normoxia group (P < 0.05). The expression of HIF-1α of xenografts in hypoxia group and normoxia group were similar. The blood growth rate of xenografts in hypoxia group (170%) was significantly higher than that of normoxia group (40%) (P < 0.05). The expression of Nrf2 of xenografts in hyperoxia group was significantly higher than that of normoxia group (P < 0.05). CONCLUSIONS: When hyperoxia induces the overexpression of HIF-1α in LNCaP tumor, it will not affect tumor growth. It provides a new ideas and theoretical basis for the clinical treatment of prostate cancer.