Enhanced antitumor effects of low‑frequency ultrasound and microbubbles in combination with simvastatin by downregulating caveolin‑1 in prostatic DU145 cells

Xu,Wei‑Ping; Shen,E.; Bai,Wen‑Kun; Wang,Yu; Hu,Bing

doi:10.3892/ol.2014.2005

Enhanced antitumor effects of low‑frequency ultrasound and microbubbles in combination with simvastatin by downregulating caveolin‑1 in prostatic DU145 cells

Authors:
- Wei‑Ping Xu
- E. Shen
- Wen‑Kun Bai
- Yu Wang
- Bing Hu
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Affiliations: Department of Ultrasound in Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai 200233, P.R. China
Published online on: March 28, 2014 https://doi.org/10.3892/ol.2014.2005
Pages: 2142-2148

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Abstract

Advanced prostate cancer is difficult to treat due to androgen resistance, its deep location and blood tumor barriers. Low‑frequency ultrasound (LFU) has potential clinical applications in the treatment of prostate cancer due to its strong penetrability and high sensitivity towards tumor cells. Simvastatin has often been administered as a preventive agent in prostate tumors. The aim of the present study was to investigate the enhanced effects of LFU and microbubbles in combination with simvastatin, in inhibiting cell viability and promoting apoptosis of androgen‑independent prostatic DU145 cells. Cultured DU145 cells were divided into six groups based on the combination of treatments as follows: Control, LFU, LFU and microbubbles (LFUM), simvastatin, LFU and simvastatin, LFUM and simvastatin. The cells were treated by LFU (80 kHz) continuously for 30 sec with an ultrasound intensity of 0.45 W/cm2 and a microbubble density of 20%. Simvastatin was added 30 h prior to the ultrasound exposure. The results indicated that cell viability was marginally reduced in the LFU and simvastatin alone treatment groups compared with the control 24 h following ultrasound exposure. The combination of LFU, with microbubbles or simvastatin, potentiated the growth inhibition; the greatest inhibition was observed in the cells that were subject to treatment with LFUM and simvastatin in combination. Furthermore, this inhibitory effect was enhanced in a time‑dependent manner. For cell apoptosis, a low dose of simvastatin had no apparent affect on the DU145 cells, while LFU marginally promoted cell apoptosis. Microbubbles or simvastatin increased the apoptosis rate of the DU145 cells, however, the combination of LFUM and simvastatin induced a strong synergistic effect on cell apoptosis. Western blotting analysis demonstrated a high expression level of caveolin‑1 in resting DU145 cells. LFUM or combined LFU and simvastatin resulted in a greater reduction in the expression compared with the control group (P<0.05). The expression of caveolin‑1 was lowest in the LFUM combined with simvastatin treatment group. The expression of phospho‑Akt (p‑Akt) was consistent with caveolin‑1, with the lowest expression levels of p‑Akt observed in the cells that were treated with the combination of LFUM and simvastatin. The results indicate that LFUM in combination with simvastatin may additively or synergistically inhibit cell viability and induce apoptosis of DU145 cells by downregulating caveolin‑1 and p‑Akt protein expression.

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1	Jemal A, Siegel R, Ward E, Hao Y, Xu J, Murray T and Thun MJ: Cancer statistics. CA Cancer J Clin. 58:71–96. 2008.
2	She Ben: Annual Report On Health and Population Health Status of Beijing 2011 (Chinese Edition). People’s Health Publishing House; Beijing, China: 2012, (In Chinese).
3	Thamilselvan V, Menon M and Thamilselvan S: Carmustine enhances the anticancer activity of selenite in androgen-independent prostate cancer cells. Cancer Manag Res. 4:383–395. 2012. View Article : Google Scholar : PubMed/NCBI
4	Williams TM, Hassan GS, Li J, et al: Caveolin-1 promotes tumor progression in an autochthonous mouse model of prostate cancer: genetic ablation of Cav-1 delays advanced prostate tumor development in tramp mice. J Biol Chem. 280:25134–25145. 2005. View Article : Google Scholar
5	Williams TM and Lisanti MP: Caveolin-1 in oncogenic transformation, cancer, and metastasis. Am J Physiol Cell Physiol. 288:C494–C506. 2005. View Article : Google Scholar : PubMed/NCBI
6	Toepfer N, Childress C, Parikh A, Rukstalis D and Yang W: Atorvastatin induces autophagy in prostate cancer PC3 cells through activation of LC3 transcription. Cancer Biol Ther. 12:691–699. 2011. View Article : Google Scholar : PubMed/NCBI
7	Bansal D, Undela K, D’Cruz S and Schifano F: Statin use and risk of prostate cancer: a meta-analysis of observational studies. PLoS One. 7:1–11. 2012. View Article : Google Scholar : PubMed/NCBI
8	Chang CC, Ho SC, Chiu HF and Yang CY: Statins increase the risk of prostate cancer: a population-based case-control study. Prostate. 71:1818–1824. 2011. View Article : Google Scholar : PubMed/NCBI
9	Murtola TJ, Syvälä H, Pennanen P, Bläuer M, Solakivi T, Ylikomi T and Tammela TL: Comparative effects of high and low-dose simvastatin on prostate epithelial cells: the role of LDL. Eur J Pharmacol. 673:96–100. 2011. View Article : Google Scholar : PubMed/NCBI
10	Rosenthal I, Sostaric JZ and Riesz P: Sonodynamic therapy - a review of the synergistic effects of drugs and ultrasound. Ultrason Sonochem. 11:349–363. 2004.PubMed/NCBI
11	Ashush H, Rozenszajn LA, Blass M, et al: Apoptosis induction of human myeloid leukemic cells by ultrasound exposure. Cancer Res. 60:1014–1020. 2000.PubMed/NCBI
12	Korosoglou G, Hardt SE, Bekeredjian R, et al: Ultrasound exposure can increase the membrane permeability of human neutrophil granulocytes containing microbubbles without causing complete cell destruction. Ultrasound Med Biol. 32:297–303. 2006. View Article : Google Scholar
13	Korosoglou G, Behrens S, Bekeredjian R, et al: The potential of a new stable ultrasound contrast agent for site-specific targeting. An in vitro experiment. Ultrasound Med Biol. 32:1473–1478. 2006. View Article : Google Scholar : PubMed/NCBI
14	Li L, Ren CH, Tahir SA, Ren C and Thompson TC: Caveolin-1 maintains activated Akt in prostate cancer cells through scaffolding domain binding site interactions with and inhibition of serine/threonine protein phosphatases PP1 and PP2A. Mol Cell Biol. 23:9389–9404. 2003. View Article : Google Scholar
15	Kochuparambil ST, Al-Husein B, Goc A, Soliman S and Somanath PR: Anticancer efficacy of simvastatin on prostate cancer cells and tumor xenografts is associated with inhibition of Akt and reduced prostate-specific antigen expression. J Pharmacol Exp Ther. 336:496–505. 2011. View Article : Google Scholar
16	Zhang Z, Chen J, Chen L, et al: Low frequency and intensity ultrasound induces apoptosis of brain glioma in rats mediated by caspase-3, Bcl-2, and survivin. Brain Res. 1473:25–34. 2012. View Article : Google Scholar : PubMed/NCBI
17	Feng Y, Tian Z and Wan M: Bioeffects of low-intensity ultrasound in vitro: apoptosis, protein profile alteration, and potential molecular mechanism. J Ultrasound Med. 29:963–974. 2010.PubMed/NCBI
18	Spampanato C, De Maria S, Sarnataro M, et al: Simvastatin inhibits cancer cell growth by inducing apoptosis correlated to activation of Bax and down-regulation of BCL-2 gene expression. Int J Oncol. 40:935–941. 2012.PubMed/NCBI
19	Kamigaki M, Sasaki T, Serikawa M, et al: Statins induce apoptosis and inhibit proliferation in cholangiocarcinoma cells. Int J Oncol. 39:561–568. 2011.PubMed/NCBI
20	Relja B, Meder F, Wilhelm K, Henrich D, Marzi I and Lehnert M: Simvastatin inhibits cell growth and induces apoptosis and G0/G1 cell cycle arrest in hepatic cancer cells. Int J Mol Med. 26:735–741. 2010. View Article : Google Scholar : PubMed/NCBI
21	Shaul PW and Anderson RG: Role of plasmalemmal caveolae in signal transduction. Am J Physiol. 275:L843–L851. 1998.PubMed/NCBI
22	Wiechen K, Diatchenko L, Agoulnik A, et al: Caveolin-1 is down-regulated in human ovarian carcinoma and acts as a candidate tumor suppressor gene. Am J Pathol. 159:1635–1643. 2001. View Article : Google Scholar : PubMed/NCBI
23	Racine C, Bélanger M, Hirabayashi H, Boucher M, Chakir J and Couet J: Reduction of caveolin 1 gene expression in lung carcinoma cell lines. Biochem Biophys Res Commun. 255:580–586. 1999. View Article : Google Scholar : PubMed/NCBI
24	Sloan EK, Stanley KL and Anderson RL: Caveolin-1 inhibits breast cancer growth and metastasis. Oncogene. 23:7893–7897. 2004. View Article : Google Scholar : PubMed/NCBI
25	Yang G, Truong LD, Timme TL, et al: Elevated expression of caveolin is associated with prostate and breast cancer. Clin Cancer Res. 4:1873–1880. 1998.PubMed/NCBI
26	Thompson TC, Tahir SA, Li L, et al: The role of caveolin-1 in prostate cancer: clinical implications. Prostate Cancer Prostatic Dis. 13:6–11. 2010. View Article : Google Scholar : PubMed/NCBI
27	Iguchi K, Matsunaga S, Nakano T, Usui S and Hirano K: Inhibition of caveolin-1 expression by incadronate in PC-3 prostate cells. Anticancer Res. 26:2977–2982. 2006.PubMed/NCBI
28	Schlicher RK, Radhakrishna H, Tolentino TP, Apkarian RP, Zarnitsyn V and Prausnitz MR: Mechanism of intracellular delivery by acoustic cavitation. Ultrasound Med Biol. 32:915–924. 2006. View Article : Google Scholar : PubMed/NCBI
29	Meijering BD, Juffermans LJ, van Wamel A, et al: Ultrasound and microbubble-targeted delivery of macromolecules is regulated by induction of endocytosis and pore formation. Circ Res. 104:679–687. 2009. View Article : Google Scholar : PubMed/NCBI
30	Zundel W, Swiersz LM and Giaccia A: Caveolin 1-mediated regulation of receptor tyrosine kinase-associated phosphatidylinositol 3-kinase activity by ceramide. Mol Cell Biol. 20:1507–1514. 2000. View Article : Google Scholar : PubMed/NCBI
31	Li L, Ittmann MM, Ayala G, et al: The emerging role of the PI3-K-Akt pathway in prostate cancer progression. Prostate Cancer Prostatic Dis. 8:108–118. 2005. View Article : Google Scholar : PubMed/NCBI