The Influence Of RACK1 Gene Silencing On The Xenograft And Chemosensitivity Of Human Lung Adenocarcinoma In Nude Mice

Objective:To study the influence of RACK1 gene silensing on the growth rate of the xenograft and chemosensitivity to DDP and PTX chemotherapy in nude mice.Methods:1.To establish the subcutaneous xenograft model in nude mice by using human lung cancer A549 cells.2.Tumor bearing nude mice were randomly divided into 3 groups when the tumor diameter was 0.3cm-0.5cm,and 18 rats in each group were injected with normal saline,empty plasmid liposome complex and sh RNA plasmid liposome complex.3.Tumor bearing nude mice were randomly divided into 3 groups after transfection successfully,and 6 rats in each group were injected with DDP,PTX and normal saline.intraperitoneal chemotherapy administered every other day.4.To observe the tumor volume changes of the three groups transfection and chemotherapy before and after,the tumor volume of nude mice were recorded and the expression of RACK1 protein was detected by Western blot.5.The tumor was stripped off when nude mice were sacrificed at 28 days.A part of the transplanted tumor were stained by HE afer immersing in 4% formalin fixed solution.The other part were detected by Western blot after storing in liquid nitrogen.Results:1.We have successfully established subcutaneous xenograft model by using human lung adenocarcinoma A549 cells,which has been detected in pathology by HE staining.The model has similar pathological features to human lung adenocarcinoma.2.After establishing subcutaneous xenograft model 28 days,the volume of subcutaneous xenograft in RACK1-sh RNA group is 197.04±39.24mm3,the tumor weight is 0.17±0.04g;the volume of subcutaneous xenograft in Vector-sh RNA group is 275.35±61.71mm3,the tumor weight is 0.27 ± 0.06g;the volume of subcutaneous xenograft in Control group is 298.66 ± 49.29mm3,the tumor weight is 0.28 ± 0.06g;differences has statistics significance(F=6.56,P<0.05).3.The xenograft tissue relative expression of RACK1 protein were detected by Western blot,and the results were:(0.21±0.11),(0.76±0.08)?(0.83±0.05).The test results for statistical analysis indicate that comparing with Vector-sh RNA group and Control group,the relative expression of RACK1 protein in RACK1-sh RNA group have obviously difference(F=97.53,P<0.05).4.The volume of subcutaneous xenograft in RACK1-sh RNA group which was administered with DDP intraperitoneal chemotherapy was 144.56±25.94mm3,the tumor weight is 0.08 ± 0.05g;The volume of subcutaneous xenograft in Vector-sh RNA group which was administered with DDP intraperitoneal chemotherapy was 220.58 ±38.39mm3,the tumor weight is 0.20 ± 0.09g;The volume of subcutaneous xenograft in Control group which was administered with DDP intraperitoneal chemotherapy was264.34±44.87mm3,the tumor weight is 0.25±0.04g;The test results for statistical analysis indicate that comparing with Vector-sh RNA group and Control group,the tumor growth rate in RACK1-sh RNA group was slower when the subcutaneous xenograft was established at 14 days,21 days,28 days.differences has statistics significance(F14day=6.03,F21day=10.25,F28day=15.90,Ftumor weight=12.27,P<0.05).5.The volume of subcutaneous xenograft in RACK1-sh RNA group which was administered with PTX intraperitoneal chemotherapy was 150.54±24.82mm3,the tumor weight is 0.09 ± 0.03g;The volume of subcutaneous xenograft in Vector-sh RNA group which was administered with PTX intraperitoneal chemotherapy was 238.42 ±46.17mm3,the tumor weight is 0.24 ± 0.07g;The volume of subcutaneous xenograft in Control group which was administered with PTX intraperitoneal chemotherapy was239.63±22.58mm3,the tumor weight is 0.27±0.05g;The test results for statistical analysis indicate that comparing with Vector-sh RNA group and Control group,the tumor growth rate in RACK1-sh RNA group was slower when the subcutaneous xenograft was established at 14 days,21 days,28 days.differences has statistics significance(F14day=14.43,F21day=16.04,F28day=14.42,Ftumor weight=18.05,P<0.05).Conclusion:1.Silencing the expression of RACK1 gene effectively inhibited the growth rate of lung adenocarcinoma in nude mice.2.sh RNA targeted silencing the expression of RACK1 gene can promote the sensitivity of human lung adenocarcinoma A549 cells in nude mice to DDP and PTX medicines;RACK1 is expected to become a new target for the treatment of lung adenocarcinoma.