ABSTRACT
Objective:To investigate the influence of glucose regulatory protein 78 (GRP78) on prognosis and tumor cell proliferation of hepatocellular carcinoma.Methods:The experimental study and retrospective cohort study were conducted. Based on hepatocellular carcinoma tissue chip, in vitro culture of Huh7 and Hep3B hepatoma cells and LO2 normal hepatic cell, and combined with immunohistochemical staining, cell transfection, quantitative real-time polymerase chain reaction (qRT-PCR), Western blot detection, cell proliferation experiments, cell clone formation experiments and high-throughput transcription histological analysis, the GRP78 expression in hepatoma cells was analyzed. Huh7 and Hep3B hepatoma cells being transfected with the GRP78 gene-specific shRNA lentiviruses or the negative control shRNA lentivirus were set as the GRP78 gene-specific shRNA lentivirus group and the negative control shRNA lentivirus group respectively. Observation indicators: (1) GRP78 expression in hepatocellular carcinoma tissue and adjacent tissue and its correlation with the clinicopathological characteristics of hepatocellular carcinoma patients; (2) analysis of factors affecting the prognosis of hepatocellular carcinoma patients; (3) effects of inhibiting of GRP78 expression on the proliferation of hepatoma cells; (4) effects of inhibiting of GRP78 expression on the gene and protein expression of p53, p21, CDK2, CDK4, and CDK6 in hepatoma cells; (5) effects of HA15 on the proliferation and the gene and protein expression of p53, p21, CDK2, CDK4, and CDK6 in hepatoma cells. Measurement data of the normal distribution were expressed as Mean± SD, and comparison of groups was conducted using the t test or ANOVA. Repeated measurement data were analyzed using repeated ANOVA. Count data were expressed as absolute numbers, and comparisons between groups was conducted using the chi-square test. COX proportional hazards regression model was used for univariate and multivariate analysis. The Kaplan-Meier method was used to calculate the survival time and draw survival curve, and the Log-rank test was used for generative analysis. Results:(1) GRP78 expression in hepatocellular carcinoma tissue and adjacent tissue and its correlation with the clinicopathological characteristics of hepatocellular carcinoma patients: results of immunohistochemical staining of hepatocellular carcinoma tissue chip showed that GRP78 was low-expressed in 53 cases and high-expressed in 37 cases of the 90 hepatocellular carcinoma tissues. GRP78 was low-expressed in 84 cases and high-expressed in 6 cases of the 90 paracancerous tissues. There was a significant difference in GRP78 expression between hepatocellular carcinoma tissues and paracancerous tissues ( P<0.05). (2) Analysis of factors affecting the prognosis of hepatocellular carcinoma patients: all 90 patients were followed up for 5 to 56 months, with a median follow-up time of 49 months. The median overall survival time and median disease progression-free survival time were 56 months and 53 months in the 53 hepatocellular carcinoma patients with GRP78 as low-expressed, versus 32 months and 19 months in the 37 hepatocellular carcinoma patients with GRP78 as high-expressed, respec-tively, showing significant differences ( χ2=17.482, 12.097, P<0.05). Results of univariate analysis showed that alanine aminotransferase (ALT), tumor pathological grading and GRP78 expression were related factors affecting the 3-year overall survival rate and disease progression-free survival rate of hepatocellular carcinoma patients ( hazard ratio=2.317, 2.039, 3.740 and 2.194, 2.177, 2.927, 95% confidence interval as 1.150?4.671, 1.201?3.462, 2.116?6.612 and 1.048?4.593, 1.093?4.336, 1.492?5.742, P<0.05). Results of multivariate analysis showed that ALT >40 U/L, tumor pathological grading as Ⅲ-Ⅳ grade and GRP78 as high-expressed were independent risk factors affecting the 3-year overall survival rate and disease progression-free survival rate of hepatocellular carcinoma patients ( hazard ratio=2.438, 2.245, 3.223 and 3.046, 2.473, 3.307, 95% confidence interval as 1.114?5.334, 1.047?4.814, 1.396?7.440 and 1.337?6.940, 1.141?5.360, 1.399?7.819, P<0.05). (3) Effects of inhibiting of GRP78 expression on the proliferation of hepatoma cells: ①results of qRT-PCR showed that the relative expression of GRP78 messenger RNA (mRNA) in Huh7, Hep3B, and LO2 cells were 3.06±0.33, 4.42±0.60 and 1.00±0.02. There were significant differences in GRP78 mRNA expression between Huh7 and LO2 cells or Hep3B and LO2 cells ( t=6.19, 5.42, P<0.05). ②Results of Western Blot detection showed that the relative expression of GRP78 protein in Huh7, Hep3B, and LO2 cells were 1.65±0.01, 1.77±0.01 and 0.99±0.02. There were significant differences in GRP78 protein expression between Huh7 and LO2 cells or Hep3B and LO2 cells ( t=75.09, 108.10, P<0.05). ③Results of cell proliferation experiments showed that the growth rates in Hu7 GRP78 gene-specific shRNA lentiviruses group cells and Hu7 negative control shRNA lentivirus group cells at 24, 48, 72 and 96 hours were 111.51%±0.35%, 144.85%±0.68%, 188.71%±3.62%, 282.51%±5.25% and 190.08%±0.58%, 285.76%±2.69%, 459.51%±4.29%, 597.88%±12.25%, showing signifi-cant differences ( Fgroups=1 360.000, Ftime=668.500, Finteraction=197.600, P<0.05). The growth rates in Hep3B GRP78 gene-specific shRNA lentiviruses group cells and Hep3B negative control shRNA lentivirus group cells at 24, 48, 72 and 96 hours were 124.47%±0.25%, 153.25%±1.25%, 195.45%±3.19%, 282.51%±10.76% and 179.69%±0.33%, 322.67%±2.46%, 486.27%±5.82%, 622.35%±12.58%, showing significant differences ( Fgroups=1 222.000, Ftime=706.200, Finteraction=179.600, P<0.05). ④Results of the cell clone formation experiments showed that the number of cells in Hu7 GRP78 gene-specific shRNA lentiviruses group cells and Hu7 negative control shRNA lentivirus group cells were 125±3 and 435±17, showing a significant difference ( t=17.86, P<0.05). The number of cells in Hep3B GRP78 gene-specific shRNA lentiviruses group cells and Hep3B negative control shRNA lentivirus group cells were 138±3 and 388±7, showing a significant difference ( t=32.29, P<0.05). (4) Effects of inhibiting of GRP78 expression on the gene and protein expression of p53, p21, CDK2, CDK4, and CDK6 in hepatoma cells: results of high-throughput transcription histological analysis showed that the relative expression rates of p53, p21, CDK2, CDK4, and CDK6 were 19%, 334%, 398%, 41% and 49% in the Hu7 GRP78 gene-specific shRNA lentiviruses group cells comparing to the Hu7 negative control shRNA lentivirus group cells. ①Results of qRT-PCR showed that the relative expression of GRP78, p53, p21, CDK2, CDK4, and CDK6 mRNA were 0.17±0.03, 4.05±0.71, 3.73±0.47, 0.49±0.09, 0.48±0.06, 0.36±0.07 in the Hu7 GRP78 gene-specific shRNA lentiviruses group cells, versus 1.00±0.05, 1.03±0.17, 1.00±0.07, 1.01±0.09, 1.02±0.14, 1.00±0.03 in the Hu7 negative control shRNA lentivirus group cells, showing significant differences ( t=14.62, 4.17, 5.72, 4.26, 3.49, 8.82, P<0.05). The relative expression of GRP78, p53, p21, CDK2, CDK4, and CDK6 mRNA were 0.11±0.01, 4.28±0.43, 4.19±0.22, 0.44±0.01, 0.25±0.03, 0.68±0.04 in Hep3B GRP78 gene-specific shRNA lentiviruses group cells, versus 1.01±0.09, 1.02±0.15, 1.00±0.06, 1.01±0.09, 1.01±0.08, 1.15±0.02 in Hep3B negative control shRNA lentivirus group cells, showing significant differences ( t=10.19, 7.14, 13.79, 6.37, 9.42, 9.61, P<0.05). ②Results of Western Blot detection showed that the relative expression of GRP78, p53, p21, CDK2, CDK4, and CDK6 protein were 0.45±0.01, 1.98±0.05, 2.31±0.12, 0.75±0.03, 0.69±0.04, 0.82±0.03 in the Hu7 GRP78 gene-specific shRNA lentiviruses group cells, versus 1.01±0.05, 1.03±0.01, 1.00±0.02, 1.00±0.01, 1.01±0.02, 1.00±0.03 in the Hu7 negative control shRNA lentivirus group cells, showing significant differences ( t=11.07, 14.56, 11.30, 11.29, 10.55, 11.37, P<0.05). The relative expression of GRP78, p53, p21, CDK2, CDK4, and CDK6 protein were 0.61±0.03, 1.98±0.16, 2.55±0.12, 0.85±0.03, 0.78±0.01, 0.54±0.02 in Hep3B GRP78 gene-specific shRNA lentiviruses group cells, versus 1.00±0.03, 1.05±0.02, 1.05±0.01, 1.05±0.02, 1.00±0.02, 1.00±0.02 in Hep3B negative control shRNA lentivirus group cells, showing significant differences ( t=10.97, 13.40, 12.35, 11.06, 12.45, 13.78, P<0.05). (5) Effects of HA15 on the proliferation and the gene and protein expression of p53, p21, CDK2, CDK4, and CDK6 in hepatoma cells: results of 50% inhibiting concentration (IC50) test of HA15 showed that the IC50 of HA15 for Huh7 and Hep3B cells at 48 hours were 9.98 μmol/L and 13.70 μmol/L. ①Huh7 and Hep3B cells were treated with 9.98 μmol/L and 13.70 μmol/L of HA15. Results of cell proliferation experiments showed that the growth rates at 24, 48, 72, and 96 hours were 112.81%±0.27%, 154.71%±1.45%, 237.66%±16.77%, 294.40%±14.92% in the HA15-Huh7 cells, versus 133.67%±0.49%, 352.93%±2.31%, 557.17%±4.89%, 662.60%±13.31% in the normal Huh7 cells, showing a significant difference ( Fgroups=766.800, Ftime=518.200, Finteraction=133.300, P<0.05). The growth rates at 24, 48, 72, and 96 hours were 121.27%±2.32%, 203.85%±3.18%, 240.80%±3.02%, 286.50%±7.10% in the HA15-Hep3B cells, versus 239.14%±1.02%, 362.00%±5.44%, 539.37%±10.80%, 694.79%±17.13% in the normal Hep3B cells, showing a signifi-cant difference ( Fgroups=594.300, Ftime=317.900, Finteraction=78.600, P<0.05). ②Results of qRT-PCR showed that the relative expression of GRP78, p53, p21, CDK2, CDK4, and CDK6 mRNA were 0.27±0.05, 3.64±0.28, 4.13±0.41, 0.51±0.07, 0.39±0.03, 0.17±0.02 in the HA15-Huh7 cells, versus 1.02±0.14, 1.00±0.03, 1.00±0.05, 1.01±0.08, 1.01±0.09, 1.03±0.17 in the normal Huh7 cells, showing significant differences ( t=5.00, 9.25, 7.63, 4.73, 6.82, 5.01, P<0.05). The relative expression of GRP78, p53, p21, CDK2, CDK4, and CDK6 mRNA were 0.28±0.03, 3.49±0.78, 4.31±0.53, 0.38±0.05, 0.36±0.04, 0.24±0.03 in the HA15-Hep3B cells, versus 1.01±0.11, 1.03±0.18, 1.01±0.08, 1.00±0.06, 1.02±0.15, 1.00±0.06 in the normal Hep3B cells, showing significant differences ( t=6.26, 3.08, 6.21, 7.97, 4.26, 11.08, P<0.05). ③Results of Western Blot detection showed that the relative expression of GRP78, p53, p21, CDK2, CDK4, and CDK6 protein were 0.52±0.05, 1.94±0.08, 1.58±0.02, 0.89±0.00, 0.86±0.02, 0.74±0.01 in the HA15-Huh7 cells, versus 1.02±0.03, 1.00±0.03, 1.02±0.02, 1.04±0.03, 1.00±0.01, 1.01±0.02 in the normal Huh7 cells, showing significant differences ( t=11.54, 10.28, 11.03, 12.81, 13.67, 10.09, P<0.05). The relative expression of GRP78, p53, p21, CDK2, CDK4, and CDK6 protein were 0.57±0.02, 1.67±0.04, 1.41±0.04, 0.82±0.03, 0.70±0.02, 0.74±0.01 in the HA15-Hep3B cells, versus 1.03±0.01, 0.98±0.03, 1.00±0.03, 1.03±0.03, 1.01±0.01, 1.04±0.01 in the normal Huh7 cells, showing significant differences ( t=10.81, 11.54, 12.26, 13.62, 14.23, 10.17, P<0.05). Conclusions:High expression of GRP78 is an independent risk factor affecting the overall survival and disease progression-free survival of hepatocellular carcinoma patients. Inhibiting of GRP78 expression can reduce cell proliferation and the expression of p53, p21, CDK2, CDK4, and CDK6 mRNA and proteins in hepatoma cells.