Tumor suppressive lncRNA MEG3 binds to EZH2 and enhances CXCL3 methylation in gallbladder cancer.

Gallbladder cancer is a malignant tumor with a high mortality rate. Accumulating evidence supports that lncRNA MEG3 may halt the progression of gallbladder cancer, while the downstream mechanism is rarely studied. Thus, we aim to investigate the molecular basis of the tumor-suppressing role of lncRNA MEG3 in gallbladder cancer. The expression of lncRNA MEG3 and CXCL3 was measured in patient serum and cell lines of gallbladder cancer. The viability, apoptosis, migration, and invasion of gallbladder cancer cells were assessed following ectopic MEG3 expression, as detected by CCK-8, flow cytometry, and Transwell assays. The interaction among lncRNA MEG3, EZH2, and CXCL3 was explored through ChIP, RNA pull-down, and RIP assays. The effects of lncRNA MEG3 and CXCL3 on tumor growth were evaluated by a mouse xenograft model. lncRNA MEG3 was expressed at a low level in gallbladder cancer patient serum and cell lines, while CXCL3 was highly expressed. MEG3 overexpression repressed the malignant behaviors of gallbladder cancer cells and promoted their apoptosis. MEG3 was mainly localized in the nucleus. MEG3 bound to EZH2, and EZH2 catalyzed the H3K27 trimethylation of the CXCL3 promoter region. MEG3 downregulated CXCL3 by activating EZH2-mediated H3K27 trimethylation of CXCL3; MEG3 overexpression attenuated cancer cell malignant behaviors in vitro and suppressed tumor growth in vivo in gallbladder cancer by inhibiting CXCL3 expression. Altogether, our results indicate that lncRNA MEG3 impedes gallbladder cancer development via the EZH2-CXCL3 axis, offering potential biomarkers for gallbladder cancer management.

[The study of the relationship between microlymphatic vessel density and lymph metastasis in hepatocellular carcinoma].

Not Abstract.

[Quantitative analysis and significance of CXCL12 and CXCR4 expression with lymphangiogenesis of pancreatic adenocarcinoma].

OBJECTIVE: To investigate the expression of CXCL12, its receptor CXCR4 and its correlations with clinical pathology and lymphangiogenesis in pancreatic adenocarcinoma (PAC). METHODS: The tissue samples were obtained from 30 patients with PAC by surgery between January 2005 and December 2007, which including PAC, the cancerous peripheral tissues, the normal pancreatic tissues and peripheral lymph nodes. The patients age ranged from 35 to 78 years old (median 57.2 years old). The expressions of CXCL12 and CXCR4 in these tissues were assayed by immunohistochemical staining, RT-PCR and fluorescence quantitative real-time PCR. RESULTS: In the immunohistochemical staining, the CXCL12 protein mainly located in the normal pancreatic cell envelopes and/or cytolymphs. In the immunohistochemical staining, the CXCR4 protein mainly located in the cell envelopes and/or cytolymphs of PAC. The results of RT-PCR and fluorescence quantitative real-time PCR indicated that the expression levels of CXCR4 mRNA in PAC tissues, the cancerous peripheral tissues and peripheral lympho nodes were higher than that in the normal pancreatic tissues (P < 0.01). The MLVD in PAC were detected by morphometric analysis respectively. The level of MLVD in III-IV stages was higher than I-II stages of PAC (P < 0.01), and in these cases which had lymphatic metastasis, the level of MLVD significantly increased (P < 0.01). And there was no correlation between the differentiation and histology types of PAC (P > 0.05). There was 22 samples that the CXCR4 protein was positive, and among these samples the MLVD was higher than that in negative group of CXCR4 protein (P = 0.003). CONCLUSIONS: The expression of CXCR4 was significantly associated with lymphatic metastasis of PAC, and the higher expression of CXCR4 in PAC tissues was significantly associated with lymphangiogenesis of PAC.

The chemotactic interaction between CCL21 and its receptor, CCR7, facilitates the progression of pancreatic cancer via induction of angiogenesis and lymphangiogenesis.

BACKGROUND: In this study, we report the influence of CCL21 and its receptor, CCR7, on the progression of pancreatic cancer and illuminates the correlation between the CCL21/CCR7 axis and the angiogenesis and lymphangiogenesis of pancreatic adenocarcinoma (PAC). METHODS: A total of 30 patients with pancreatic cancer was involved in the current study. The expression of CCL21 and CCR7 in cancerous tissues, paracancerous tissues and normal pancreas were investigated using real-time PCR, Western blot and immunohistochemistry, respectively. In addition, we assessed microvessel density (MVD) and microlymphatic vessel density (MLVD) in tumor tissues using immunohistochemistry. RESULTS: Compared to paracancerous tissues and normal pancreas, CCL21 expression in cancerous tissues was detected at a significantly low level. In contrast, the CCR7 expression was considerably higher in cancerous tissues than in normal pancreas and paracancerous tissues. Additionally, a significant correlation between the expression pattern of the CCL21/CCR7 axis and clinicopathological features, such as lymph node metastasis, was identified. Furthermore, we found that CCL21 expression was significantly associated with MVD but not significantly associated with MLVD, while CCR7 expression was significantly associated with MLVD but not significantly associated with MVD. CONCLUSIONS: The chemotactic interaction between CCR7 and its ligand, CCL21, may be a critical event during progression in pancreatic cancer, and its underlying mechanism may be induction of angiogenesis and lymphangiogenesis regulated by this chemotactic interaction.

Mechanisms of TRAIL and gemcitabine induction of pancreatic cancer cell apoptosis.

The aim of this study was to investigate induction of apoptosis by the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and gemcitabine in the pancreatic cancer cell line SW1990. The sensitivity of SW1990 cells to TRAIL and/or gemcitabine-induced apoptosis and the rate of apoptosis were assessed by MTT assay and flow cytometry, respectively. We used Hoechst 33342 staining to observe apoptotic morphology and expression levels of proteins were analyzed by Western blottin. Growth inhibition and apoptosis rates on treatment with the combination of TRAIL and gemcitabine were significantly higher than with each drug alone (p<0.05). Pancreatic cancer cells exhibited a typical apoptosis morphology after treatment with TRAIL or gemcitabine. The levels of cellular apoptosis-associated proteins such as Smac/DIABLO, Cyto C, and the activated fragment of caspase-3 (P17) increased, but the expression of XIAP was significantly decreased after 24 h (p<0.05). SW1990 cells responded to TRAIL and/or gemcitabine-induction of apoptosis in a time and concentration-dependent manner. The mechanism of the apoptosis-sensitization effect appeared associated with significant up-regulation of Smac/DIABLO and cytochrome C, down-regulation of XIAP, and activation of caspase-3.

Effect of 5-LOX/COX-2 common inhibitor DHDMBF30 on pancreatic cancer cell Capan2.

AIM: To study the effect of 5-lipoxygenase/cyclooxygenase-2 (5-LOX/COX-2) dual inhibitor 7-tert-butyl-2, 3-dihydro-3, 3-dimethyl substituted dihydrofuran 30 (DHDMBF30) on proliferation and apoptosis of the pancreatic cancer cell line Capan-2 and the effect of DHDMBF30 on human pancreatic cancer in a nude mouse model. METHODS: Investigate the effect of 5-LOX/COX-2 dual inhibitor DHDMBF30 on proliferation and apoptosis of the pancreatic cancer cell line Capan-2 by RT-PCR, MTT assay, FCM and electron microscope. Cell line Capan-2 was inoculated percutaneously on the outer thigh of 12 nude mice. The VEGF mRNA of transplantation tumor was detected by RT-PCR. RESULTS: DHDMBF30 inhibits the proliferation of cell line Capan2, reduces the expression of 5-LOX, COX-2 and VEGF. After Capan2 was treated with DHDMBF30, we found that the apoptosis peak of the experimental group was significantly higher than that of the contrast group (3.08 +/- 1.89 vs 27.67 +/- 0.52, P < 0.001). The tumor weight of the DHDMBF30 group was significantly lower than PBS control groups (1.35 +/- 0.47 vs 2.92 +/- 0.73, P < 0.01). Expression of VEGF in the DHDMBF30 group was significantly decreased. CONCLUSION: DHDMBF30 inhibits the proliferation of the pancreatic cell line Capan2, and induces apoptosis and inhibits the growth of pancreatic cancer in nude mice.

Expression of vascular endothelial growth factors-C and -D correlate with evidence of lymphangiogenesis and angiogenesis in pancreatic adenocarcinoma.

BACKGROUND: We analyzed the intratumoral and peritumoral microvessel density (MVD) and microlymphatic vessel density (MLVD) in pancreatic adenocarcinoma (PAC) and recorded the expression of vascular endothelial growth factor (VEGF)-C and -D. These data were tested for their significance for tumor progression. METHODS: The tissue samples were obtained from 30 patients with PAC. The expression of VEGF-C and -D, MLVD, MVD was assayed by immunohistochemical staining. The expression of VEGF-A and -C, and -D mRNA was detected by semi-quantitative RT-PCR. RESULTS: Immunohistochemical analysis revealed the presence of VEGF-C and -D immunoreactivity in 73% (22/30) and 57% (17/30). The positive rates of VEGF-C and -D protein in central portion of tumors (30% and 16.7%) were significantly lower than those in marginal portion (73.3% and 56.7%). The group with high expression of VEGF-C and -D in marginal portion had higher incidence of lymph node metastasis, lymphatic invasion and venous invasion. The MLVD in both of the VEGF-C and -D positive groups was higher than that in the negative groups, and the lymph node metastasis increased. MVD in the VEGF-C positive group was higher than that in the negative group. CONCLUSIONS: The expression of VEGF-C and -D in the marginal portion of tumor significantly associated with lymphatic metastasis and prognosis in patients with PAC, and may induced lymphangiogenesis. VEGF-C was important in the regulation of angiogenesis and lymphangiogenesis in PAC.