Effects of pioglitazone combined with radiotherapy on colon carcinoma xenograft in mice

Objective To investigate the effects of peroxisome proliferator activated receptor γ(PPARγ) agonists pioglitazone combined with radiotherapy on colon carcinoma xenograft in mice.Methods The colon cancer cells CT26 of mouse were inoculated in the right side of the rib loins of BALB/c mouse.Established BALB/c mice tumor models.The mice were randomly divided into six groups:untreated group,tumor contral group,DMSO group,pioglitazone treated group,radiotherapy group,radiotherapy combined with pioglitazone treated group.To observe the tumor growth of each group,to compute and compare to the tumor inhibition rates.the pathological varieties of the tumor were observed.Results The tumor volumes were compared with each group after two weeks of radiotherapy.Compared with tumor contral group,pioglitazone treated group,radiotherapy group and radiotherapy combined with pioglitazone treated group could decrease the volume of tumor (P =0.008,P =0.001,P =0.001).Compared with pioglitazone treated group,the effect of radiotherapy group or radiotherapy combined with pioglitazone treated group was more evident (P =0.026,P =0.018).Contrasted with radiotherapy group,radiotherapy combined with pioglitazone treated group had no significant difference (P =0.335).The tumor inhibition rates of pioglitazone treated group,radiotherapy group and radiotherapy combined with pioglitazone treated group were 46.30 ％,68.60 ％ and 70.01％.The pathological varieties of tumor were obvious.Conclusion Pioglitazone,radiotherapy and radiotherapy combined with pioglitazone could inhibit the growth of tumor.PPARγ is a new target for tumor treatment. Key words: Peroxisome proliferator activated receptor γ; Pioglitazone; Radiotherapy; Mice; Colon carcinoma