JulieIrene, How are you doing? [Archive] - HER2 Support Group Forums

Lani

12-05-2009, 12:32 AM

I seem to remember Julierene had a p53 issue--I found this and thought of her:

Carcinogenesis vol.25 no.10 2004

Lovastatin inhibits tumor growth and lung metastasis in mouse mammary carcinoma model: a p53-independent mitochondrial-mediated apoptotic mechanism

Masa-Aki Shibata1,2,4, Yuko Ito1, Junji Morimoto3 and Yoshinori Otsuki1,2,4
1 Department of Anatomy and Biology, 2 High-Tech Research Center and 3 Laboratory Animal Center, Osaka Medical College, 2–7 Daigaku-machi, Takatsuki, Osaka 569-8686, Japan

4 To whom correspondence should be addressed Email: an1014@art.osaka-med.ac.jp or an1001@art.oska-med.ac.jp

Abstract

The effects of lovastatin, a potent inhibitor of hydroxymethylglutaryl-coenzyme A reductase, were studied in a mouse model of metastatic mammary cancer carrying a p53 mutation. Mice bearing mammary tumors, induced by inoculation of syngeneic BALB/c mice with BJMC3879 cells, were treated with lovastatin at 0, 25 and 50 mg/kg three times a week. Tumor volumes were significantly reduced in a dose-dependent manner throughout the 6 week study and were associated with both a decrease in DNA synthesis and an increase in apoptosis. The high dose of lovastatin also inhibited lung metastasis. In a corollary in vitro study, flow cytometric analyses of lovastatin-treated mammary cancer cells additionally showed cell cycle arrest at G1 phase and decreases in S and G2/M phases. Laser scanning cytometric analyses further demonstrated that cancer cells in S and G2/M were particularly susceptible to the effects of lovastatin. Transmission electron microscopic evaluation of TUNEL-confirmed apoptotic bodies in lovastatin-treated mammary carcinoma cells revealed many free 3'-OH ends of DNA in condensed chromatin within fragmented nuclei that occasionally assumed a characteristic half-moon shape. Consistent with initiation of apoptosis, cellular caspase-8, caspase-9 and caspase-3 activities were elevated in lovastatin-treated cells. The mitochondrial membrane potential was also decreased, with subsequent release of cytochrome c. However, lovastatin-induced cell death was significantly reduced by the broad spectrum caspase inhibitor z-VAD-fmk, as well as the caspase-9 inhibitor z-LEHD-fmk and the caspase-3 inhibitor z-DEVD-fmk, but not by the specific caspase-8 inhibitor z-IETD-fmk. Since immunoelectron microscopy showed translocation of Bax to the mitochondria in lovastatin-treated cells, lovastatin-induced apoptosis may, therefore, be ultimately dependent on Bax induction of cytochrome c release. These results suggest that lovastatin may be useful as an adjuvant therapy in breast cancers containing p53 mutations due to its ability to both suppress DNA synthesis and induce p53-independent mitochondria-mediated apoptosis.