Effect of NOR1 gene knockout on nude mice xenograft tumor of human liver cancer and its mechanism of action

Objective To investigate the effect of NOR1 gene knockout on the growth of nude mice xenograft tumor of human liver cancer,the survival rate of nude mice,and organ damage in nude mice. Methods A total of 30 specific pathogen-free male BALB/C nude mice were randomly divided into control group,Scramble group,and siNOR1 group,with 10 mice in each group. The negative control plasmid( Scramble) and siNOR1 plasmid were transfected into HepG2 cells,and then the HepG2 cells were inoculated into nude mice to establish a nude mouse model of xenograft tumor. The volume and weight of nude mice xenograft tumor were measured every 5 days for 30 consecutive days. Immunohistochemistry was used to measure the expression of Ki-67,caspase-3,Notch,and NOR1,and Western Blot was used to measure the protein expression of Survivin,Notch1,NICD,Hes1,and Hey1. HE staining was used to observe the degree of pathological injury in the liver,the kidney,the lungs,and the brain. A one-way analysis of variance was used for comparison between multiple groups,and the least significant difference t-test was used for further comparison between two groups. The Kaplan-Meier method was used for survival analysis,and the log-rank test was used for comparison of survival rates. Results Compared with the control group since day 20 of modeling,the siNOR1 group had a significantly lower volume of xenograft tumor on days 20,25,and 30( day 20: 149. 6. 16 ± 60. 05 mm3 vs 418. 71 ± 78. 24 mm3,P < 0. 05; day 25: 239. 83 ± 100. 51 mm3 vs 864. 22 ± 125. 66 mm3,P < 0. 05; day 30: 446. 54 ± 147. 09 mm3 vs1468. 45 ± 199. 78 mm3,all P < 0. 05). The xenograft tumor was collected on day 30,and compared with the control group,the siNOR1 group had a significantly lower weight of xenograft tumor( 0. 12 ± 0. 04 g vs 0. 45 ± 0. 07 g,P < 0. 05). Compared with the control group,the siNOR1 group had significantly lower expression of Ki-67,Notch,and NOR1 in xenograft tumor tissue( Ki-67: 11. 51% ± 5. 09% vs48. 98% ± 9. 75%,P < 0. 05; Notch: 18. 75% ± 4. 61% vs 62. 51% ± 9. 26%,P < 0. 05; NOR1: 16. 57% ± 3. 76% vs 76. 33% ±8. 31%,P < 0. 05),as well as significantly higher expression of caspase-3( 38. 03% ± 9. 28% vs 6. 39% ± 4. 67%,P < 0. 05). The siNOR1 group had a significantly higher 30-day survival rate than the control group( 77. 66% ± 6. 75% vs 25. 32% ± 4. 63%,χ2= 6. 897,P < 0. 05). Western blot showed that compared with the control group,the si NOR1 group had significantly lower protein expression of Survivin( 0. 02 ± 0. 01 vs 0. 34 ± 0. 06,P < 0. 05),Notch1( 0. 03 ± 0. 01 vs 0. 16 ± 0. 03,P < 0. 05),NICD( 0. 04 ± 0. 02 vs 0. 26 ± 0. 05,P < 0. 05),Hes1( 0. 06 ± 0. 02 vs 0. 35 ± 0. 04,P < 0. 05),and Hey1( 0. 05 ± 0. 02 vs 0. 29 ± 0. 06,P < 0. 05). The si NOR1 group had a significant improvement in organ damage. Conclusion NOR1 gene knockout inhibits the growth of nude mice xenograft tumor of human liver cancer,improve the survival rate of model nude mice,and alleviate the damage of the liver,the kidney,the lungs,and the brain in model nude mice,possibly by inhibiting the activity of the Notch signaling pathway.