Effects Of The Proliferation And Apoptosis On Human Pancreatic Carcionma SW-1990 Cells Affected By BCH

Background Pancreatic carcinoma has the characteristies of early metastasis,with an over all 5-year survival rate of less than 5 percent. Although radiotherapy and chemotherapy have produced modest benefits in some patients, no currently available treatment affects survival for patients with locally advanced and metastasis disease.Similarly, for patients with localized disease,current adjuvant radiation and chemotherapy have shown only modest benefits after surgical resection. Therefore,to seek new effective therapeutic means, basic researchers and clinicians should work together. L-type amino acid transporter 1 (LAT1) is a neutral amino acid transport system and is a major route for the transport of large neutral amino acids through the plasma membrane. LAT1 has been associated with tumor growth and been proved that highly expressing in the hyperplastic tissue,established cancer cell lines and primary human neoplasms. LAT1 has scarcely been detected in the normal tissues of the grown-up,except cerebrum,orchis,optomeninx and placenta. Many aspects of life science have been involved in the research of LAT1,including diagnosis, therapeutics, metachoresis and prognosis of neoplasma. 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid(BCH) has been discovered as an specific inhibitor of system L amino acid transporters, We have examined the effects and the mechanisms of the proliferation and apoptosis on human pancreatic carcinoma SW-1990 Cells affected by BCH.Purpose To detect the effects of the proliferation and apoptosis on human pancreatic carcionma SW-1990 Cells affected by BCH. Investigate the probable mechanisms of suppresses and apoptosis.Methods Expression of LAT1 were evaluated by immunofluorescence in cultured pancreatic cancer cell lines SW-1990. The effect and the mechanism of BCH on cell growth suppression in cancer cells were examined using amino acid transport measurement, MTT assay; The morphologic changes of SW-1990 Cells were observed with inverted microscope. AnnexinⅤ-FITC/PI staining,Flow cytometery shew the apoptosis rate change ; Colorimetric method was used to measure the activities of caspase-3 of SW-1990 cells incubated with BCH for12h,24h,48h,72h; The pro-caspase-3 protein was tested using western blot analysis.Results High level expression of LAT1 was recognized at plasma membrane and cytoplasm of SW-1990 Cells. BCH inhibited [3H]L-leucine transport in a concentration-dependent manner in SW-1990 Cells with IC50 values 74.20±4.50μmol/L. MTT assay shows from 0.3 to 30mmol/L treatment of BCH, the inhibition of cancer cell growth depended on the BCH treatment time.When the cells were treated with BCH at 0.3, 1, 3, 10, 30mmol/L, BCH inhibited the proliferation of cancer cells in a dose-dependent manner with IC50 values of 24h:27.61±5.15 mmol/L;48h:20.10±1.97 mmol/L;72h:9.94±1.07 mmol/L;Typical morphological changes of SW-1990 Cells were observed in microscopy.SW-1990 Cells could be induced to undergo apoptosis after 20mmol/L BCH treatment for 12h,24h,48h,the apoptotic rate was(4.78±0.42)%,(12.44±1.03)%,(26.54±1.72)%, Compared with the control group(0.82±0.19)%, it was significantly higher(P<0.001).Treatment with 20mmol/L BCH(12h,24h,48h,72h)significantly promoted activation of caspase-3 in the SW-1990 Cells with a increase in the amount of caspase-3.caspase-3 protein levels were increased by (2.07±0.36),(3.56±0.64),(4.75±0.67),(3.16±0.04)fold compare with the control group(P=0.018); Furthermore, proteolytic cleavage of pro-caspase-3 in BCH-treated SW-1990 Cells was confirmed by Western blot. changes in the expression of pro-caspase-3 protein were at a time-dependent manner (P<0.001).Conclusion The results suggest that the inhibition of LAT1 activity by BCH leads to apoptotic cancer cell death by inducing intracellular depletion of neutral amino acids necessary for cancer cell growth. BCH induces apoptotic cell death through caspases-dependent processing.