Inhibitory Effect And Mechanism Of Mesenchymal Stem Cells On NSCLC Cells

Aim:Non-small cell lung cancer(NSCLC)is still the main threat of cancer-associated death.Approximately 85%of lung cancer belongs to NSCLC.Traditional therapies for cancer treatments mainly are surgical resection,chemotherapy,and radiotherapy.Owning to the difficulty of detection for lung cancer at the early phase,it was usually at the advanced phase when NSCLC was diagnosed,thus the survival rates of treated patients were extremely low in five years and the prognosis remains poor.For that reason,novel strategies for cancer treatments are urgently needed.Among which,stem cell therapy draws much attention of the public.It was reported that Mesenchymal stem cells(MSCs)exhibit the feature of homing to tumor sites and possess characteristics of lower immunogenicity and anti-tumor effect,which make MSCs a perfect candidate for cancer therapy.According to the researches,a broad repertoire of trophic factors secreted by MSCs extensively involve in the interplay between MSCs and various tumor cells,which includes liver cancer,breast cancer and melanoma.NSCLC is heterogeneous tumor which can be classified according to different tissue types and the pathological mechanism of NSCLC remains to be diversity,that's part of reasons why consequence of stem cell therapy on NSCLC shows contradiction.Therefore,this study extensively explored the effect of MSCs on the proliferation and migration ability of different tissue-derived NSCLC cells,and furtherly investigate whether MAPK/eIF4E signaling pathway involve in molecular mechanism which is responsible for the inhibitory effect of MSCs on NSCLC cells.Methods:In order to systematically explore the effect of MSCs on NSCLC cells,A549,H460 and MES cells,which derived from adenocarcinoma,large cell carcinoma and squamous cell carcinoma respectively,was selected as research models.Firstly,Transwell migration assay was conducted to confirm the homing ability of MSCs to different tissue-derived NSCLC cells;Then MTT assay was used to detect the viability of different tissue-derived NSCLC cells after co-cultured with MSCs.Next,cell scratch assay was used to explore the effect of MSCs on the migration ability of different tissue-derived NSCLC cells.And finally,Gene Expression Microarray Assay and western blot were used to investigate the molecular mechanism involved in the interplay between MSCs and NSCLC cells.Results:Migration assay showed MSCs significantly migrate to different tissue-derived NSCLC cells,and the number of migration to A549 cells(118 ± 17.06)is more than that of migration to MES cells(93 ± 4.24)and H460 cells(64.25 ± 4.03)MTT assay demonstrated that MSCs significantly inhibit the viability of NSCLC cells when co-cultured with different tissue-derived NSCLC cells.And the inhibitory rates were increased in line with elevation of MSCs ratio.The maximal inhibitory rate of MSCs on H460 reached 30.67%± 1.30,which was higher than that of MSCs on A549 cells(26.99%± 3.44)and on MES cells(25.35%± 0.39).When NSCLC cells were treated by MSCs CM,the inhibitory effect on the viability of NSCLC cells was also detected by MTT assay.Results revealed that inhibitory rates came to maximum at the condition of 100%MSCs CM for 48 h,which were(63.08%±1.38)for H460,(39.99%± 6.05)for A549 and(26.03%± 2.82)for MES.Western blot analysis revealed that the expressions of PCNA\Bcl2 and Akt which respectively related to cell proliferation,anti-apoptosis and migration were significantly down-regulated.Besides,the expressions of p44/p42MAPK and phospho-p44/p42MAPK,eIF4E and phospho-eIF4E and phospho-MNK1 also remarkably reduced.Human Gene Expression Microarray Assay showed MSCs highly secreted VEGF,which is profoundly involved in MAPK signaling pathway.Particularly,human-derived recombinant protein VEGF 165 could partly mimic consequence which caused by MSCs,when VEGF in the MSCs CM was neutralized by VEGF neutralizing antibody,the inhibitory effect of MSCs CM on NSCLC cells was reversed to some extent.Conclusion:MSCs exhibited the homing ability to different tissue-derived NSCLC cells,and also significantly inhibited proliferation and migration of NSCLC cells via indirect manners.VEGF secreted by MSCs involved in MAPK/eIF4E pathway to regulate proteins which were related to cell proliferation,migration and apoptosis,and this regulation pattern might be responsible for the inhibitory effect on tumor.