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Diet-induced hypercholesterolemia promotes androgen-independent prostate cancer metastasis via IQGAP1 and caveolin-1.

Moon H, Ruelcke JE, Choi E, Sharpe LJ, Nassar ZD, Bielefeldt-Ohmann H, Parat MO, Shah A, Francois M, Inder KL, Brown AJ, Russell PJ, Parton RG, Hill MM - Oncotarget (2015)

Bottom Line: Obesity and metabolic syndrome are associated with several cancers, however, the molecular mechanisms remain to be fully elucidated.Down-regulation of caveolin-1 or IQGAP1 in PC-3 cells reduced migration and invasion in vitro, and hypercholesterolemia-induced metastasis in vivo.Double knock-down of caveolin-1 and IQGAP1 showed no additive effect, suggesting that caveolin-1 and IQGAP1 act via the same pathway.

View Article: PubMed Central - PubMed

Affiliation: The University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute, Brisbane, QLD, Australia.

ABSTRACT
Obesity and metabolic syndrome are associated with several cancers, however, the molecular mechanisms remain to be fully elucidated. Recent studies suggest that hypercholesterolemia increases intratumoral androgen signaling in prostate cancer, but it is unclear whether androgen-independent mechanisms also exist. Since hypercholesterolemia is associated with advanced, castrate-resistant prostate cancer, in this study, we aimed to determine whether and how hypercholesterolemia affects prostate cancer progression in the absence of androgen signaling. We demonstrate that diet-induced hypercholesterolemia promotes orthotopic xenograft PC-3 cell metastasis, concomitant with elevated expression of caveolin-1 and IQGAP1 in xenograft tumor tissues. In vitro cholesterol treatment of PC-3 cells stimulated migration and increased IQGAP1 and caveolin-1 protein level and localization to a detergent-resistant fraction. Down-regulation of caveolin-1 or IQGAP1 in PC-3 cells reduced migration and invasion in vitro, and hypercholesterolemia-induced metastasis in vivo. Double knock-down of caveolin-1 and IQGAP1 showed no additive effect, suggesting that caveolin-1 and IQGAP1 act via the same pathway. Taken together, our data show that hypercholesterolemia promotes prostate cancer metastasis independent of the androgen pathway, in part by increasing IQGAP1 and caveolin-1. These results have broader implications for managing metastasis of cancers in general as IQGAP1 and hypercholesterolemia are implicated in the progression of several cancers.

No MeSH data available.


Related in: MedlinePlus

Knockdown of IQGAP1 and/or caveolin-1 in PC-3 cells reduces migration and invasion in vitroPC-3-luciferase cell lines with reduced expression of IQGAP1 (shIQGAP1), caveolin-1 (shCav1) and both (shIQ+shCav) were generated using lentiviral-mediated shRNA. (a) Relative protein expression of IQGAP1 and caveolin-1 was measured by immunoblotting and quantified over 3 experiments. (b) Transmigration, (c) Matrigel invasion and (d) proliferation assays were performed for PC-3 stable cell lines. Error bars show standard error of the mean. **p < 0.005, ***p < 0.0005. Additional shRNAs produced similar phenotypes (Supplementary Figure S7).
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Figure 5: Knockdown of IQGAP1 and/or caveolin-1 in PC-3 cells reduces migration and invasion in vitroPC-3-luciferase cell lines with reduced expression of IQGAP1 (shIQGAP1), caveolin-1 (shCav1) and both (shIQ+shCav) were generated using lentiviral-mediated shRNA. (a) Relative protein expression of IQGAP1 and caveolin-1 was measured by immunoblotting and quantified over 3 experiments. (b) Transmigration, (c) Matrigel invasion and (d) proliferation assays were performed for PC-3 stable cell lines. Error bars show standard error of the mean. **p < 0.005, ***p < 0.0005. Additional shRNAs produced similar phenotypes (Supplementary Figure S7).

Mentions: To further evaluate the involvement of IQGAP1 and caveolin-1 in PC-3 metastases in vivo, we performed hypercholesterolemic diet xenograft experiments using PC-3-luc cell lines with reduced IQGAP1 and/or caveolin-1 expression. Firstly, pooled populations of shIQGAP1 and shCav1 PC-3 cells were established using lentiviral mediated shRNAs and flow cytometry (based on the bicistronic co-expression of GFP in the lentivirus). A double knockdown cell line was generated by infecting shIQGAP1 cells with shCav1 lentivirus. Reduced protein levels were confirmed by Western blotting (Figure 5a). Preliminary in vitro studies showed similar attenuation of transmigration and invasion between shIQGAP1, shCav1 and double knockdown cells compared to scrambled control (Figure 5b, 5c and Supplementary Figure S7). There was no difference in proliferation between the 4 cell lines (Figure 5d). Before performing in vivo study, the intensity and linearity of in vitro bioluminescence of PC-3-luc shIQGAP1 and shCav1 cell lines were confirmed for accurate comparison between groups (Supplementary Figure S8).


Diet-induced hypercholesterolemia promotes androgen-independent prostate cancer metastasis via IQGAP1 and caveolin-1.

Moon H, Ruelcke JE, Choi E, Sharpe LJ, Nassar ZD, Bielefeldt-Ohmann H, Parat MO, Shah A, Francois M, Inder KL, Brown AJ, Russell PJ, Parton RG, Hill MM - Oncotarget (2015)

Knockdown of IQGAP1 and/or caveolin-1 in PC-3 cells reduces migration and invasion in vitroPC-3-luciferase cell lines with reduced expression of IQGAP1 (shIQGAP1), caveolin-1 (shCav1) and both (shIQ+shCav) were generated using lentiviral-mediated shRNA. (a) Relative protein expression of IQGAP1 and caveolin-1 was measured by immunoblotting and quantified over 3 experiments. (b) Transmigration, (c) Matrigel invasion and (d) proliferation assays were performed for PC-3 stable cell lines. Error bars show standard error of the mean. **p < 0.005, ***p < 0.0005. Additional shRNAs produced similar phenotypes (Supplementary Figure S7).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4480691&req=5

Figure 5: Knockdown of IQGAP1 and/or caveolin-1 in PC-3 cells reduces migration and invasion in vitroPC-3-luciferase cell lines with reduced expression of IQGAP1 (shIQGAP1), caveolin-1 (shCav1) and both (shIQ+shCav) were generated using lentiviral-mediated shRNA. (a) Relative protein expression of IQGAP1 and caveolin-1 was measured by immunoblotting and quantified over 3 experiments. (b) Transmigration, (c) Matrigel invasion and (d) proliferation assays were performed for PC-3 stable cell lines. Error bars show standard error of the mean. **p < 0.005, ***p < 0.0005. Additional shRNAs produced similar phenotypes (Supplementary Figure S7).
Mentions: To further evaluate the involvement of IQGAP1 and caveolin-1 in PC-3 metastases in vivo, we performed hypercholesterolemic diet xenograft experiments using PC-3-luc cell lines with reduced IQGAP1 and/or caveolin-1 expression. Firstly, pooled populations of shIQGAP1 and shCav1 PC-3 cells were established using lentiviral mediated shRNAs and flow cytometry (based on the bicistronic co-expression of GFP in the lentivirus). A double knockdown cell line was generated by infecting shIQGAP1 cells with shCav1 lentivirus. Reduced protein levels were confirmed by Western blotting (Figure 5a). Preliminary in vitro studies showed similar attenuation of transmigration and invasion between shIQGAP1, shCav1 and double knockdown cells compared to scrambled control (Figure 5b, 5c and Supplementary Figure S7). There was no difference in proliferation between the 4 cell lines (Figure 5d). Before performing in vivo study, the intensity and linearity of in vitro bioluminescence of PC-3-luc shIQGAP1 and shCav1 cell lines were confirmed for accurate comparison between groups (Supplementary Figure S8).

Bottom Line: Obesity and metabolic syndrome are associated with several cancers, however, the molecular mechanisms remain to be fully elucidated.Down-regulation of caveolin-1 or IQGAP1 in PC-3 cells reduced migration and invasion in vitro, and hypercholesterolemia-induced metastasis in vivo.Double knock-down of caveolin-1 and IQGAP1 showed no additive effect, suggesting that caveolin-1 and IQGAP1 act via the same pathway.

View Article: PubMed Central - PubMed

Affiliation: The University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute, Brisbane, QLD, Australia.

ABSTRACT
Obesity and metabolic syndrome are associated with several cancers, however, the molecular mechanisms remain to be fully elucidated. Recent studies suggest that hypercholesterolemia increases intratumoral androgen signaling in prostate cancer, but it is unclear whether androgen-independent mechanisms also exist. Since hypercholesterolemia is associated with advanced, castrate-resistant prostate cancer, in this study, we aimed to determine whether and how hypercholesterolemia affects prostate cancer progression in the absence of androgen signaling. We demonstrate that diet-induced hypercholesterolemia promotes orthotopic xenograft PC-3 cell metastasis, concomitant with elevated expression of caveolin-1 and IQGAP1 in xenograft tumor tissues. In vitro cholesterol treatment of PC-3 cells stimulated migration and increased IQGAP1 and caveolin-1 protein level and localization to a detergent-resistant fraction. Down-regulation of caveolin-1 or IQGAP1 in PC-3 cells reduced migration and invasion in vitro, and hypercholesterolemia-induced metastasis in vivo. Double knock-down of caveolin-1 and IQGAP1 showed no additive effect, suggesting that caveolin-1 and IQGAP1 act via the same pathway. Taken together, our data show that hypercholesterolemia promotes prostate cancer metastasis independent of the androgen pathway, in part by increasing IQGAP1 and caveolin-1. These results have broader implications for managing metastasis of cancers in general as IQGAP1 and hypercholesterolemia are implicated in the progression of several cancers.

No MeSH data available.


Related in: MedlinePlus