Relationship Between Poly(ADP-Ribose) Polymerase/Poly(ADP-Ribose) Glycohydrolase And Microangiogenesis In Colorectal Carcinoma

AIM: The aim is to investigate the relationship between Poly(ADP-ribose) polymerase(PARP)/ Poly(ADP-ribose) glycohydrolase (PARG) and microangiogenesis in colorectal carcinoma.METHODS: Immunohistochemical SP staining was used to examine the expression of poly(ADP-ribose) (PAR), PARP, PARG and the change of microvessel density (MVD) in colorectal carcinoma. The positive rate of MMP-9 in murine colon carcinoma CT26 cell was detected by Flow Cytometry (FCM). RT-PCR was used to detect the expression of PARG mRNA. The positive rate of PARP in CT26 was detected by FCM. The activation of MMP-9 in CT26 was detected by Western Blot.RESULTS: 1. MVD was various in colorectal carcinoma with different positive staining of PAR. MVD was high(28.86±13.49) in colorectal carcinoma with strong positive staining PAR(+++), and it was low(18.17±1.94) in colorectal carcinoma with weak positive PAR(+) (P<0.05). The positive rate of MMP-9 in 5-AIQ-untreated CT26 cell group was 86.75% and 69.33% in 5-AIQ-treated CT26 cell group. The positive rate of MMP-9 in 5-AIQ-treated CT26 was weaker than that in 5-AIQ-untreated CT26 (P<0.05).2. The correlation of PARG and PARP expression in colorectal carcinoma was positive (P<0.05). The expressions of PARG, MMP-9 and PARP were attenuated in GLTN-treated CT26 cell groups compared with that in GLTN-untreated CT26 cell groups (P<0.05).CONCLUSION: 1. MVD was various in colorectal carcinoma with different positive staining of PAR. MVD in the group with strong positive PAR was higher than that in the group with weak positive PAR. The results suggest that the expression of PARP is correlated with microangiogenesis in colorectal carcinoma and there is relationship with increasing expression of MMP-9.2. The expression of PARG was enhanced in colorectal carcinoma with strong expression of PARP. The correlation of PARG and PARP expressed in colorectal carcinoma was positive. The expression of PARP and MMP-9 were decreased after PARG inhibition. The results suggest PARG could regulate the expression of PARP and may play a role in the progress of microangiogenesis in carcinoma.