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Mu Z , Hachem P , Hensley H , Stoyanova R , Kwon HW , Hanlon AL , Agrawal S , Pollack A
Antisense MDM2 enhances the response of androgen insensitive human prostate cancer cells to androgen deprivation in vitro and in vivo
Prostate. 2008 May 1;68(6) :599-609
PMID: 18196567   
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Abstract
BACKGROUND: Antisense MDM2 oligonucleotide (AS-MDM2) sensitizes androgen sensitive LNCaP cells to androgen deprivation (AD) in vitro and in vivo. In this study, we investigated the effects of AS-MDM2 combined with AD on androgen resistant LNCaP (LNCaP-Res) and moderately androgen resistant bcl-2 overexpressing LNCaP (LNCaP-BST) cells. METHODS: The LNCaP-Res cell line was generated by culturing LNCaP cells in medium containing charcoal-stripped serum for more than 1 year. Apoptosis was quantified in vitro by Annexin V staining and caspase 3 + 7 activity. For the in vivo studies, orthotopic tumor growth was monitored by magnetic resonance imaging (MRI). AS-MDM2 and the mismatch control were given by i.p. injection at doses of 25 mg/kg per day, 5 days/week for 15 days. RESULTS: LNCaP-Res cells expressed high levels of androgen receptor (AR) and bcl-2, and displayed no growth inhibition to AD. AS-MDM2 caused significant reductions in MDM2 and AR expression, and increases in p53 and p21 expression in both cell lines. AS-MDM2 + AD resulted in the highest levels of apoptosis in vitro and tumor growth inhibition in vivo in both cell lines; although, these effects were less pronounced in LNCaP-BST cells. CONCLUSIONS: AS-MDM2 + AD enhanced apoptotic cell death in vitro and tumor growth inhibition in vivo in androgen resistant cell lines. The action of AS-MDM2 + AD was influenced somewhat by bcl-2 expression as an isolated change (LNCaP-BST cells), but not when accompanied by other molecular changes associated with androgen insensitivity (LNCaP-Res cells). MDM2 knockdown has promise for the treatment of men with early hormone refractory disease.
Notes
Mu, Zhaomei Hachem, Paul Hensley, Harvey Stoyanova, Radka Kwon, Hae Won Hanlon, Alexandra L Agrawal, Sudhir Pollack, Alan CA 101984-01/CA/NCI NIH HHS/United States CA-006927/CA/NCI NIH HHS/United States Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. United States The Prostate Prostate. 2008 May 1;68(6):599-609.