重视我国胰腺癌的研究现状及发展趋势

Triptolide suppresses 5-lipoxygenase metabolic pathway and induces apoptosis in pancreatic tumor cell lines

AIM: To investigate the effects and the mechanism of triptolide (TL) on proliferation and apoptosis of pancreatic cancer in vitro.

METHODS: Pancreatic tumor cell lines PANC-1, ASPC-1 and SW1990 were treated with different concentrations of TL for 24 h and then, cell death was determined by Typan Blue Staining. Annexin V/PI double staining was performed to evaluate TL-induced apoptosis using flow cytometry. The expression of 5-lipoxygenase (5-LOX) and concentration of its downstream product LTB₄ were determined by real time PCR, Western blot and ELISA. 5-LOX cDNA stable transfected SW1990 cells were established successfully. After treatment with TL, it was examined for overexpression of 5-LOX on TL-induced apoptosis.

RESULTS: TL induced prominent growth inhibition and apoptosis in human pancreatic cancer cell lines. After treatment at 50 μg/L, the cell viability was 70.5% ± 6.8%, 61.2% ± 5.6% and 52.8% ± 5.3% of PANC-1, ASPC-1 and SW1990, respectively, which were significantly decreased compared with control group (P < 0.05). The apoptosis at 12 h evaluated by AnnexinV positive cells increased in TL-treated group compared with control group (24.2 ± 3.23 vs 9.5 ± 2.18, P < 0.05). TL significantly down-regulated 5-LOX expression in these cell lines and decreased LTB₄ concentration in supernatant (P < 0.01, compared with control group). Furthermore, overexpression of 5-LOX in SW1990 cells made them more resistant to TL induced apoptosis, significantly inhibited the TL mediated cell death and apoptosis (P < 0.01 or 0.05, compared with control group).

CONCLUSION: Inhibition of 5-LOX pathway of arachidonic acid metabolism is associated with TL's anti-proliferation and pro-apoptotic activity. It also provides evidence that TL has clinic therapeutic value for patients with pancreatic cancer.

5-lipoxygenase suppresses TNF-α-induced apoptosis in pancreatic tumor cell lines

AIM: To investigate the effects of 5-lipoxygenase and LTB4 on the proliferation and apoptosis of pancreatic cancer cells in vitro.

METHODS: The human pancreatic cancer cell lines ASPC-1, PANC-1 and SW1990 were cultured and the levels of 5-LOX and the supernatant product LTB4 were examined by Western blot and ELISA. TNF-α-induced cell apoptosis was analyzed by annexin V/PI double staining with flow cytometry. 5-LOX cDNA stably transfected SW1990 cell lines were established and treated with TNF-α. Their sensitivity to apoptosis induction was examined.

RESULTS: The pancreatic cell lines tested in this study all expressed substitute levels of 5-LOX and LTB4. The percentages of apoptotic wild-type SW1990 cells were 25.4% ± 3.65% and 43.5% ± 5.23% after 12 h and 24 h treatment with 20 μg/L TNF-α, respectively. However, these effects were significantly decreased (P < 0.01) in 5-LOX over-expressing cells. The percentages of these cells undergoing apoptosis were 13.2% ± 2.01% and 21.7% ± 3.65% after 12 h and 24 h treatment, respectively. Furthermore, the addition of exogenous LTB4 (10 nmol/L) significantly suppressed the percentage of wild-type cells undergoing apoptosis from 47.6% ± 5.32% to 18.5% ± 5.69%. Blocking LTB4 signals with specific receptor antagonists reversed the sensitivity of 5-LOX transfected cells to apoptosis.

CONCLUSION: High levels of expression of 5-LOX and LTB4 make pancreatic cell lines more resistant to TNF-α-induced apoptosis, suggesting that the 5-LOX pathway plays an important role in the pathogenesis of pancreatic cancer.

Application of surface-enhanced laser desorption/ionization time-of-flight mass spectrometry for early detection of pancreatic cancer

Pancreatic cancer is a devastating and lethal disease. Early detection continues to be a serious, unsolved problem. However, proteomics is emerging as a powerful new tool for the diagnosis of pancreatic cancer. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) is a new technique that allows for rapid high-throughput screening of protein expression in clinical samples. The progress and challenges in applying SELDI-TOF MS to protein biomarker discovery in pancreatic cancer are reviewed in this paper.