Specific inhibition of gene expression and transactivation functions of hepatitis B virus X protein and c-myc by small interfering RNAs.
With a view to developing therapeutic strategies against hepatocellular carcinoma (HCC), we have recently shown that co-expression of c-myc and the X protein of hepatitis B virus (HBx) resulted in the development of HCC in the X-myc transgenic mice. We now show in cell culture-based studies that small interfering RNA (siRNA) corresponding to HBx and c-myc can regulate expression and transactivation of the target genes. Expression vectors for small hairpin RNAs (shRNAs) against two different regions each of the HBx and c-myc open reading frames were constructed and their regulatory effects were investigated in COS-1 cells. A dose-dependent specific inhibition in the expression levels of HBx and c-myc was observed with individual shRNAs. Further, the recombinantly expressed shRNAs also blocked the transactivation functions of their cognate genes. Though each shRNA worked at a different efficiency, the inhibitory effects with two different shRNAs were cumulative. These results appear promising for developing a siRNA-based therapy for HCC.
Hung
Le
L
Virology Group, International Centre for Genetic Engineering and Biotechnology, P.O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India.
Kumar
Vijay
V
D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D019556:COS Cells; D002472:Cell Transformation, Viral; D002522:Chlorocebus aethiops; D015967:Gene Expression Regulation, Viral; D005822:Genetic Vectors; D008163:Luminescent Measurements; D051379:Mice; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D016271:Proto-Oncogene Proteins c-myc / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D034741:RNA, Small Interfering / Q000037:antagonists & inhibitors*; D012367:RNA, Viral / Q000302:isolation & purification / Q000378:metabolism; D017422:Sequence Analysis, DNA; D015534:Trans-Activators / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D015533:Transcriptional Activation; D054334:Viral Regulatory and Accessory Proteins
D016271:Proto-Oncogene Proteins c-myc; D034741:RNA, Small Interfering; D012367:RNA, Viral; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein