Transfection of HCC lines with wild-type p53 and a reporter with the promoter from the p53-responsive gene WAF1/p21 resulted in a high level of expression, as expected.
Our data indicate that p21(CIP2/Waf1) overexpression may not be the only regulatory factor necessary for RA-induced apoptosis in human hepatoma Hep3B cells.
These results suggest that: (1) different modes of p21(WAF1/CIP1) regulation are involved in HCCs differing in their hepatitis viral infection status, and p21(WAF1/CIP1) expression appears to be predominantly related to altered p53 in HCV-related HCCs; (2) disruption of the p53-p21(WAF1/CIP1) cell-cycle-regulating pathway may contribute to malignant progression of HCC.
Our results also emphasize the chemotherapeutic potential of p21(waf1/cip1) inhibitors, particularly in the HBV-X infected hepatoma which lacks functional p53.
These findings raise the potential that forced upregulation of p21(WAF1/CIP1) in hepatocellular carcinoma (HCC) may reduce the doses of cisplatin to achieve similar responses and suggest the possible use of p21(WAF1/CIP1) in HCC treatment.
The transcriptional induction of plasminogen activator inhibitor-1 and p21(WAF1/CIP1) by TGF-beta were detected in all HCC cell lines, implying that the molecular integrity of the TGF-beta receptors might be intact.
Our study has provided molecular evidence to demonstrate that wogonin and fisetin had effective cytotoxic effects through apoptosis induction in hepatocellular carcinoma cells SK-HEP-1; activation of caspase 3 cascade, induction of p53 protein and alternative expression of p21(Waf/Cip-1) protein were involved.
In this study, we first demonstrated that TF (5-30 microM) induced apoptosis in several types of human cancer cell lines including human hepatoma (Hep G2), colorectal cancer (COLO 205), and fibroblast (CCD 922SK) cells for 24 h. The cellular responses to TF-induced apoptosis were demonstrated to be associated with the p53-signaling pathway, including induction of p53, p21/Cip1, p27/Kip1, bax protein expression and inhibition of bcl-2 protein expression.
Thus, downregulation of p21(waf/cip-1) in HCC cells functions as a novel, critical determinant of alternative growth inhibitory pathways in response to IFN-gamma.
The results demonstrated that combined administration of p21(WAF-1) and GM-CSF could remarkably inhibit the growth of subcutaneously transplanted hepatoma Hepa cells, and significantly increase the survival rate of tumor-bearing mice.
In human hepatocellular carcinoma in cirrhosis proliferating cell nuclear antigen (PCNA) is involved in cell proliferation and cooperates with P21 in DNA repair.
We reported here that overexpression of integrin beta1 imposed a growth inhibitory effect on the hepatocellular carcinoma cell line SMMC-7721, and this phenomenon was mainly attributed to the cyclin-dependent kinase inhibitor p21(CIP1).
The results showed that p53 over-expression is a reliable marker for mutational modulation of p53 function. p53 was negatively correlated with p21/WAF1 in hepatitis B virus-related HCC (p=0.024, r=-0.432).
The results showed that p53 over-expression is a reliable marker for mutational modulation of p53 function. p53 was negatively correlated with p21/WAF1 in hepatitis B virus-related HCC (p=0.024, r=-0.432).
After the transfection of alpha-1,3-fucosyltransferase (FucT)-VII cDNA into H7721 human hepatocarcinoma cells, the protein expression of some cyclins, cyclin-dependent kinases (CDKs) and cyclin-dependent kinase inhibitors (CDIs) p16INK4 and p21waf1/Cip1 were unchanged.
The positive rate of HBcAg expression in cancerous tissues of 40 HCCs was 20.0%, which was also lower than that in para-cancerous and adjacent normal liver tissues (chi2 = 9.482, P < 0.01; chi2 = 14.645, P < 0.01). p21 protein deletion rate in cancerous tissues of 40 HCCs was 27.5%, which was higher than that in para-cancerous and adjacent normal liver tissues (chi2 = 7.439, P < 0.01; chi2 = 11.174, P < 0.01). p21 protein deletion correlated remarkably with the pathological grade of HCC (chi2 = 0.072, P < 0.05).
Molecular mechanism of cell cycle blockage of hepatoma SK-Hep-1 cells by Epimedin C through suppression of mitogen-activated protein kinase activation and increased expression of CDK inhibitors p21(Cip1) and p27(Kip1).
These effects were accompanied by downregulation of proteins involved in anti-apoptosis (Bcl-xL, XIAP or c-IAP2) and cell-cycle progression (cyclin D1), and induction of proteins involved in pro-apoptosis (Bax) and cell-cycle retardation (p21Waf1/Cip1), although the degree of changes by DHMEQ was different in each hepatoma cell type.
We previously reported that overexpression of integrin beta1 subunit imposed a growth inhibitory effect on the hepatocellular carcinoma cell line SMMC-7721 through transcriptional activation of p21(WAF1/CIP1) gene.