mTOR/P70S6K信号通路在肝细胞肝癌中的表达及临床意义

Effect of a TSC2 antisense oligonucleotide on cell proliferation and apoptosis in human esophageal cancer cell line EC9706

AIM: To observe the impact of a tuberous sclerosis complex 2 (TSC2)-specific antisense oligonucleotide (ASODN) on cell proliferation and apoptosis in human esophageal cancer cell line EC9706.

METHODS: A TSC2 ASODN at different concentrations (5, 10 and 15 μmol/L) was transfected into EC9706 cells using cationic liposomes. A sense oligonucleotide (15 μmol/L) and nonsense oligonucleotide (15 μmol/L) were used as negative controls, and non-transfected EC9706 cells were used as a normal control. At 24, 48 and 72 h after transfection, MTT and TUNEL assays were used to examine the proliferation and apoptosis of EC9706 cells, respectively, and immunocytochemistry and RT-PCR were used to determine the expression of TSC2.

RESULTS: Compared to the three control groups, transfection of the TSC2 ASODN increased proliferation, decreased apoptosis (13.11 ± 0.13, 9.31 ± 0.29, 4.38 ± 0.43 vs 16.46 ± 0.43, 16.63 ± 0.34, 16.23 ± 0.45, all P < 0.05), and reduced the expression of TSC2 mRNA and protein (FmRNA = 260.23, 572.22, 1004.35, Fprotein = 50.60, 330.69, 1221.28, all P < 0.05) in EC9706 cells in a time- and concentration-dependent manner. Transfection with a dose of 15 μmol/L for 72 h exhibited the most strong effect (P < 0.05).

CONCLUSION: The TSC2 ASODN could enhance proliferation and inhibit apoptosis in human esophageal cancer cell line EC9706.

Abnormal expression of cyclin-dependent kinase 5 in hepatocellular carcinoma

AIM: To investigate the abnormal expression of cyclin-dependent kinase 5 (CDK5) in hepatocellular carcinoma (HCC).

METHODS: The expression of CDK5 mRNA and protein in normal liver tissue, liver cirrhosis and HCC was measured by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. The relationship between CDK5 expression and the clinicopathological characteristics of HCC was then analyzed.

RESULTS: The expression of CDK5 mRNA was up-regulated in HCC when compared with noncancerous liver tissue. The positive rates of CDK5 mRNA expression were 29.4%, 64.3% and 89.7% in normal liver tissue, liver cirrhosis and HCC, respectively. Significant differences were noted in the positive rates of CDK5 mRNA expression between normal liver tissue and HCC (P < 0.05) and between liver cirrhosis and HCC (P < 0.01). Immunohistochemistry analysis also revealed up-regulated expression of CDK5 in HCC compared with noncancerous liver tissue. The positive rates of CDK5 protein were 29.4%, 64.3% and 89.7% in normal liver tissue, liver cirrhosis and HCC, respectively. Significant differences were noted in the positive rates of CDK5 protein expression among the three groups (χ² = 58.095, all P < 0.01). The overexpression of CDK5 is significantly correlated with the pathological grade of HCC (χ² = 19.330, P < 0.01).

CONCLUSION: CDK5 is up-regulated in HCC compared with noncancerous liver tissue. CDK5 plays an important role in the carcinogenesis of HCC. CDK5 overexpression may be related to tumor differentiation in HCC.