Effects of hypoxia-inducible factor-1α silencing on drug resistance of human pancreatic cancer cell line Patu8988/5-Fu.

The present study aimed to investigate the mechanism and the possible approaches of solving drug resistance by silencing hypoxia-inducible factor-1 alpha of human pancreatic cancer cell line Patu8988/5-Fu cultured in hypoxia. The effective jamming fragment screened by RT-PCR for silencing HIF-1α gene was transfected into pancreatic cancer cells Patu8988/5-Fu through lentivirus. RT-PCR results showed that the effective jamming fragments for HIF-1α in lentivirus transfection was Wtl-mus-1202(C546). Combined MTT with JC-1 fluorescence staining flow cytometric analysis, the concentration of 200 µmol/L CoCl2 for 8 h was chosen to mimic hypoxia cell environment. The drug resistance significantly enhanced in response to hypoxia in Patu8988/5-Fu (p<0.05), and silence HIF-1α could reverse the multidrug resistance (P<0.05). In the Patu8988/5-Fu cells, HIF-1α and MDR1 significantly increased in response to hypoxia (p<0.05). The inhibition of HIF-1α expression synergistically downregulated the expression of the MDR1 gene in Patu8988/5-Fu cells (p<0.05). HIF-1α expression was positively correlated with the MDR1 expression (p<0.05). The upregulation of the HIF-1α and MDR1 gene expression caused by hypoxia was related with the generation of multi-drug resistance of Patu8988/5-Fu, targeted silencing HIF-1α may be a kind of way to reverse the chemotherapy drug resistance.

[Assesment of genetic diversity of allelopathic rice germplasm based on RAPD and ISSR].

Random Amplified Polymorphic DNA (RAPD) and Inter-simple Sequence Repeat (ISSR) methods were used to detect the genetic diversity of 57 allelopathic rice accessions which were introduced from 10 countries or areas. A total of 12 RAPD primers and seven ISSR primers were indentified with polymorphism among the entries. For RAPD markers, 85 polymorphic bands were produced, percentage of polymorphic bands (PPB) were 69.4%. For ISSR marker, 34 polymorphic bands were generated, PPB were 53.0%. The result from the clustering analysis by UPGMA indicated that those accessions from the same geographical location were clustered into one group. It was also found that some rice accessions with higher allelopathic potential were clustered together, implying that the genes conferring allelopathy in those rice accessions might be isolocus. However, some rice accessions with different allelopathic potential clustered into the same group performed lower level of generic polymorphism which was attributed to oriented selection for other traits in breeding program. The estimates of correlation coefficient of RAPD and ISSR based on the genetic similarity matrices were significantly correlated.