Murine double minute 2 siRNA and wild-type p53 gene therapy interact positively with zinc on prostate tumours in vitro and in vivo.
Prostate cancer (PCa) often shows either mutations of the p53 gene or inactivation of the P53 protein. The latter may be due to up-regulation of mouse double minute 2 homologue (MDM2), which functions both as an E3 ubiquitin ligase to degrade P53 protein via the proteasome and an inhibitor of P53 transcriptional activation. Zinc plays a crucial role in stabilizing the P53 DNA binding domain, but PCa cells often lack the ability to accumulate sufficient zinc. In the present study, we explore the optimal approach to retention of P53 function. To restore the defective P53 pathway in PCa, we have explored a combined treatment of Pmp53 [a plasmid containing both mdm2 small interfering RNA (Si-MDM2) and the wild-type p53 gene] with zinc. This treatment retains the wild-type P53 conformation and function in PCa in vitro and in vivo. Combined treatments significantly inhibited tumour xenograft growth, retaining wild-type P53 conformation and enhancing its transcriptional regulation of p21 and bax gene expression, leading to the decreased proliferation and increased apoptosis. These in vivo findings were confirmed by in vitro culture of PCa PC-3 (p53 null) or DU145 (mutant p53) cells and showed a positive effect of the combined therapy on cell cycle arrest and massive apoptosis. Our findings suggest that the combined therapy of Pmp53 with zinc is an effective strategy that may open a new therapeutic avenue in some cancers expressing low levels of zinc and a defective P53 status.
Department of Pathophysiology, Prostate Diseases Prevention and Treatment Research Center, Norman Bethune College of Medicine, Jilin University, Changchun, China.
Junlian
J
Gu
Department of Pathophysiology, Prostate Diseases Prevention and Treatment Research Center, Norman Bethune College of Medicine, Jilin University, Changchun, China; Department of Pathology, Inner Mongolia Forestry General Hospital, Yakeshi, China.
Bo
B
Wang
Department of Pathophysiology, Prostate Diseases Prevention and Treatment Research Center, Norman Bethune College of Medicine, Jilin University, Changchun, China.
Yanan
Y
Liu
The Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun, China.
Lingzhi
L
Zhong
Department of Bone and Joint Surgery, First Hospital of Jilin University, Changchun, China.
Yufeng
Y
Tang
Department of Pathophysiology, Prostate Diseases Prevention and Treatment Research Center, Norman Bethune College of Medicine, Jilin University, Changchun, China.
Hua
H
Guo
Department of Blood and Division of Rheumatology, Jilin Province People's Hospital, Changchun, China.
Tao
T
Jiang
Department of Medical Informatics and Health Administration, School of Public Health, Jilin University, Changchun, China.
Liwei
L
Wang
Department of Pathophysiology, Prostate Diseases Prevention and Treatment Research Center, Norman Bethune College of Medicine, Jilin University, Changchun, China. Electronic address: lyang@jlu.edu.cn.
Yang
Y
Li
KCHRI at the Department of Pediatrics, The University of Louisville, Louisville, USA; Departments of Radiation Oncology, Pharmacology and Toxicology, The University of Louisville, Louisville, USA. Electronic address: l0cai001@louisville.edu.
Lu
L
Cai
D000818:Animals; D015153:Blotting, Western; D059447:Cell Cycle Checkpoints / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D010957:Plasmids / Q000235:genetics; D011471:Prostatic Neoplasms / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D047368:Tumor Burden / Q000187:drug effects / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays; D015032:Zinc / Q000008:administration & dosage / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
D050759:Cyclin-Dependent Kinase Inhibitor p21; D034741:RNA, Small Interfering; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D051736:Proto-Oncogene Proteins c-mdm2; D015032:Zinc
Gene therapy; MDM2; P53 tumour suppressor; Prostate cancer; Zinc