Cancer-associated-fibroblasts Regulate The Chemoresistance Of Lung Cancer Cell Line A549 Via SDF-1 Secretion

Lung cancer causes the severe damage to people's health.According to the world health organization(WHO)published in 2008,the mortality(1.4million)and morbidity(1.6 million)of lung cancer every year ranked the first of the world cancers.The situation is the same as In our country.The mortality of lung cancer increased by 464.8 % in the past 30 years,growing year by year.Famous British oncologists R.Peto predicted that the morbidity of lung cancer in China will be more than 1 million in 2025 if China did not control the air pollution and smoking promptly.To investigate whether cancer-associated-fibroblasts(CAF),which were the key component of tumor microenvironment,regulated chemoresistant capacity of lung cancer cell line A549 through SDF-1 secretion.at first,we utilized primary cell isolation techniques to isolate cancer-associated-fibroblasts from lung cancer patients.Secondly,MTT assay was applied to measure proliferation and chemoresistance of A549.Thirdly,quantative PCR was used to detect mRNA changes of Bcl-xl.Fourthly,western blotting was used to detect Bcl-xl expression at protein level.Finally,ELISA were applied to measure SDF-1 secretion from NF and CAF.CAF was able to promote the proliferation rate of A549,while NF had no significant effect on that.After 72 hrs incubation,A value of A549+CAFmedium group reached 0.814±0.006,was statistically different with that of A549+NFmedium group(P<0.05).As Q-PCR data indicated,mRNA expression of Bcl-xl in A549 group,A549+NF medium group and A549+CAF medium group was 1.00±0.11,1.10±0.09 and3.50±0.30 respectively.The data of A549+NF medium group was statistically different from that of A549+CAF medium group(P<0.05).As Western blot showed,protein expression of Bcl-xl in A549 group,A549+NF medium group and A549+CAF medium group was 1.00±0.08,1.10±0.12 and 3.10±0.25 respectively.The data of A549+NF medium group was statistically different from that of A549+CAF medium group(P<0.05).As ELISA results showed,SDF-1 concentration in A549+NF medium group and A549+CAF medium group 3.23±0.02 and9.53±0.10 respectively,was statistically different from each other(P<0.05).As MTT data indicated,OD of A549 group,A549+AMD3100 group,A549+NFmedium group,A549+NFmedium+AMD3100group,A549+CAFmedium and A549+CAFmedium+AMD3100 group was0.43±0.03,0.25±0.02,0.48±0.03,0.31±0.03,0.72±0.06 and 0.45±0.03,respectively.The data of A549+NF medium group was statistically different from that of A549+CAF medium group(P<0.05).cancer-associated-fibroblasts improved drug resistance of A549 through SDF-1 secretion,which upregulated the expression level of Bcl-xl via interaction with CXCR4.Here we show that tumor microenvironment was able to enhance drug resistance of tumor,but also provided evidences for as cancer-associated-fibroblasts potential therapeutic target.