Expression of survivin protein in hepatocellular carcinoma tissues and its relationship with clinical pathological features and prognosis

Inhibitory effect of antisense oligonucleotide on the expression of survivin gene and proliferation of human hepatocellular carcinoma cell line SMMC-7721

AIM: To investigate the inhibitory effect of survivin antisense oligonucleotide (ASODN) on the expression of survivin gene and proliferation of human hepatocellular carcinoma cell line SMMC-7721.

METHODS: The 20mer antisense oligonucleotide (ASODN) targeted to the promotor region of survivin mRNA was designed and synthesized. The expression of survivin gene in hepatocellular carcinoma cell line SMMC-7721 was blocked by means of ASODN transfection mediated by DOTAP liposomal reagent. The changes of survivin protein and mRNA expression after transfection were assessd by Western blot and in situ hybridization, respectively. The apoptotic rate was detected by flow cytometer. The changes of cell adherent rate, cell growth activity, and the inhibitory rate of cell growth were also studied.

RESULTS: The expression of survivin protein and mRNA was decreased markedly after survivin ASODN transfection (69.59 vs 10.71, and 75.61 vs 22.94, P < 0.01). Meanwhile, the cell adherent rate also decreased markedly (90.68% vs 33.16%, P < 0.01) while the apoptotic rate increased markedly (0.7% vs 31.35%, P < 0.01). The inhibitory effect on the cell growth could maintain about a week after transfection, and the highest inhibitory rate could be 71.8% three d after transfection.

CONCLUSION: Transfection of ASODN targeted to the promotor region of survivin mRNA by DOTAP liposomal transfection reagent can down-regulate the expression of survivin protein and mRNA significantly in 7721 cell line and inhibit the proliferation of cancer cells. survivin may be an important target in the therapy of hepatocellular carcinoma.

Relationship between expression of survivin gene and proliferation of hepatocytes in liver cirrhosis and hepatocellular carcinoma

AIM: To evaluate the usefulness of detection of cell proliferation and survivin gene in choosing liver cirrhosis patients with extremely dangerous for HCC development.

METHODS: Total RNA was extracted from fresh specimens of HCC and liver cirrhosis. Survivin mRNA amplification was performed by reverse transcription polymerase chain reaction (RT-PCR). Immunostaining for proliferating cell nuclear antigen (PCNA) was employed to assess liver cell proliferative activity in formalin-fixed, paraffin-embedded liver specimens. PCNA immunostaining in liver cells of HCC and cirrhosis fresh and archive specimens was performed with monoclonal antibodies directed against CD10. Five liver specimens removed from patients with hemangioma were taken as controls. The PCNA labeling index was determined by positive cells in each microscopic field (200×) obtained from mean value of positive cells in ten different fields.

RESULTS: RT-PCR was performed in 17 HCC and 21 liver cirrhosis specimens, 11 HCC specimens showed 344 bps molecular survivin DNA band in 1% agarose electrophoresis, but none of liver cirrhosis specimens showed positive band. The survivin positive rate in HCC specimens was 64.7% (11/17). The median PCNA labeling index of 11 survivin positive HCC specimens was 6.8 (from 0.5 to 40), which was significantly higher than that of 6 survivin negative HCC specimens (2.15), while that of 21 LC and 5 normal liver specimens were 2.47 and 1.56 respectively. By using a cutoff of PCNA labeling index (3.12) obtained by two times of the index value in normal liver specimens, six specimens of 30 liver cirrhosis patients with mean PCNA labeling index 5.05±2.61 were considered high proliferative activity.

CONCLUSION: Expression of survivin is detected in HCC tissues but not in liver cirrhosis tissues, indicating that the gene expression may occur at the late phase of HCC transformation. The PCNA detection can be a good mean in screening the high-risk people with elevated possiblity of HCC development among liver cirrhosis patients.