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Pathobiological implications of the expression of EGFR, pAkt, NF-κB and MIC-1 in prostate cancer stem cells and their progenies.

Mimeault M, Johansson SL, Batra SK - PLoS ONE (2012)

Bottom Line: The progression of prostate cancers (PCs) to locally invasive, androgen-independent and metastatic disease states is generally associated with treatment resistance and disease relapse.Moreover, the results have indicated that the EGF-EGFR signaling pathway can provide critical functions for the self-renewal of side population (SP) cells endowed with stem cell-like features from highly invasive WPE1-NB26 cells.Also, the targeting of these oncogenic products induced the caspase-dependent apoptosis in chemoresistant SP WPE1-NB26 cells and enhanced their sensibility to the cytotoxic effects induced by docetaxel.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America.

ABSTRACT
The progression of prostate cancers (PCs) to locally invasive, androgen-independent and metastatic disease states is generally associated with treatment resistance and disease relapse. The present study was undertaken to establish the possibility of using a combination of specific oncogenic products, including epidermal growth factor receptor (EGFR), pAkt, nuclear factor-kappaB (NF-κB) and macrophage inhibitory cytokine-1 (MIC-1) as biomarkers and therapeutic targets for optimizing the management of patients with localized PC at earlier disease stages. The immunohistochemical and immunofluorescence data have revealed that the expression levels of EGFR, Ser(473)-pAkt, NF-κB p65 and MIC-1 proteins were significantly enhanced in the same subset of 76 cases of prostatic adenocarcinoma specimens during the disease progression and these biomarkers were expressed in a small subpopulation of CD133(+) PC cells and the bulk tumor mass of CD133(-) PC cells. Importantly, all of these biomarkers were also overexpressed in 80-100% of 30 PC metastasis bone tissue specimens. Moreover, the results have indicated that the EGF-EGFR signaling pathway can provide critical functions for the self-renewal of side population (SP) cells endowed with stem cell-like features from highly invasive WPE1-NB26 cells. Of therapeutic interest, the targeting of EGFR, pAkt, NF-κB or MIC-1 was also effective at suppressing the basal and EGF-promoted prostasphere formation by SP WPE1-NB26 cells, inducing disintegration of SP cell-derived prostaspheres and decreasing the viability of SP and non-SP WPE1-NB26 cell fractions. Also, the targeting of these oncogenic products induced the caspase-dependent apoptosis in chemoresistant SP WPE1-NB26 cells and enhanced their sensibility to the cytotoxic effects induced by docetaxel. These findings suggest that the combined use of EGFR, pAkt, NF-κB and/or MIC-1 may represent promising strategies for improving the accuracy of current diagnostic and prognostic methods and efficacy of treatments of PC patients in considering the disease heterogeneity, thereby preventing PC progression to metastatic and lethal disease states.

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Determination of the effects induced by different drugs on the prostasphere-forming ability of the SP cell fraction from highly invasive and tumorigenic WPE1-NB26 cell line.The SP and non-SP cell fractions from the WPE1-NB26 cell line were subjected to the prostasphere formation culture on an ultra-low attachment plate in serum-free keratinocyte medium. The representative pictures of the dense prostaspheres formed by SP WPE1-NB26 cells (a) without or (b) after a treatment with exogenous EGF as compared to diffuse, abortive and very small aggregates formed by non-SP WPE1-NB26 cells are shown at a similar magnification of ×200. Moreover, the representative pictures of the prostaspheres formed by the SP WPE1-NB26 cell fraction (a) without or (b) after a treatment with exogenous EGF in the presence of different drugs, including a specific inhibitory agent of EGFR (gefitinib), PI3K (LY294002), pAkt (pAkt inhibitor VIII), NF-κB (partenolide), MIC-1 (anti-MIC-1 antibody) or docetaxel, are also shown at a similar magnification of ×200. The quantitative data of the number of prostaspheres formed by the SP WPE1-NB26 cell fraction (c) without or (d) after a treatment with exogenous EGF in the absence (control) or presence of different inhibitory agents obtained from at least 3 separate experiments are shown.
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pone-0031919-g006: Determination of the effects induced by different drugs on the prostasphere-forming ability of the SP cell fraction from highly invasive and tumorigenic WPE1-NB26 cell line.The SP and non-SP cell fractions from the WPE1-NB26 cell line were subjected to the prostasphere formation culture on an ultra-low attachment plate in serum-free keratinocyte medium. The representative pictures of the dense prostaspheres formed by SP WPE1-NB26 cells (a) without or (b) after a treatment with exogenous EGF as compared to diffuse, abortive and very small aggregates formed by non-SP WPE1-NB26 cells are shown at a similar magnification of ×200. Moreover, the representative pictures of the prostaspheres formed by the SP WPE1-NB26 cell fraction (a) without or (b) after a treatment with exogenous EGF in the presence of different drugs, including a specific inhibitory agent of EGFR (gefitinib), PI3K (LY294002), pAkt (pAkt inhibitor VIII), NF-κB (partenolide), MIC-1 (anti-MIC-1 antibody) or docetaxel, are also shown at a similar magnification of ×200. The quantitative data of the number of prostaspheres formed by the SP WPE1-NB26 cell fraction (c) without or (d) after a treatment with exogenous EGF in the absence (control) or presence of different inhibitory agents obtained from at least 3 separate experiments are shown.

Mentions: The establishment of the functions of EGFR, PI3K/pAkt, NF-κB and MIC-1 for the self-renewal of the SP cell subpopulation versus the non-SP cell fraction isolated from the highly tumorigenic and invasive WPE1-NB26 cell line was done by performing prostasphere-forming assays in the absence or presence of specific inhibitory agents of these signaling elements in serum free-keratinocyte medium under an ultra-low attachment plate. As shown in Figure 6a, the results from prostasphere-forming assays have revealed that the SP cells from the WPE1-NB26 cell line were able to generate many dense prostaspheres with a large size in culture after 7 days in the absence of EGF. Moreover, the addition of exogenous EGF into culture medium significantly promoted the number and size of prostaspheres formed by SP WPE1-NB26 cells indicating an important role of EGF-EGFR system for the self-renewal of these immature PC cells (Figure 6b). In contrast, the non-SP WPE1-NB26 cell fraction after FAC sorting formed only a small number of diffuse, abortive and very small primary prostaspheres in the absence or presence of EGF, while no secondary prostasphere was formed at the second passage as compared to the high prostasphere-forming capacity of SP WPE1-NB26 cells that was retained upon serial passage (Figure 6a and b). We have also observed that the 10 µl/ml of the pre-immune rabbit serum was used as control has not significant effect on the prostasphere-forming ability of SP WPE1-NB26 cells as compared to 10 µl/ml anti-MIC-1 antibody (data not shown). Also, the treatment with docetaxel has not significant effect on the prostasphere-forming ability of SP WPE1-NB26 cells in the absence or presence of EGF (Figure 6a and b).


Pathobiological implications of the expression of EGFR, pAkt, NF-κB and MIC-1 in prostate cancer stem cells and their progenies.

Mimeault M, Johansson SL, Batra SK - PLoS ONE (2012)

Determination of the effects induced by different drugs on the prostasphere-forming ability of the SP cell fraction from highly invasive and tumorigenic WPE1-NB26 cell line.The SP and non-SP cell fractions from the WPE1-NB26 cell line were subjected to the prostasphere formation culture on an ultra-low attachment plate in serum-free keratinocyte medium. The representative pictures of the dense prostaspheres formed by SP WPE1-NB26 cells (a) without or (b) after a treatment with exogenous EGF as compared to diffuse, abortive and very small aggregates formed by non-SP WPE1-NB26 cells are shown at a similar magnification of ×200. Moreover, the representative pictures of the prostaspheres formed by the SP WPE1-NB26 cell fraction (a) without or (b) after a treatment with exogenous EGF in the presence of different drugs, including a specific inhibitory agent of EGFR (gefitinib), PI3K (LY294002), pAkt (pAkt inhibitor VIII), NF-κB (partenolide), MIC-1 (anti-MIC-1 antibody) or docetaxel, are also shown at a similar magnification of ×200. The quantitative data of the number of prostaspheres formed by the SP WPE1-NB26 cell fraction (c) without or (d) after a treatment with exogenous EGF in the absence (control) or presence of different inhibitory agents obtained from at least 3 separate experiments are shown.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3285632&req=5

pone-0031919-g006: Determination of the effects induced by different drugs on the prostasphere-forming ability of the SP cell fraction from highly invasive and tumorigenic WPE1-NB26 cell line.The SP and non-SP cell fractions from the WPE1-NB26 cell line were subjected to the prostasphere formation culture on an ultra-low attachment plate in serum-free keratinocyte medium. The representative pictures of the dense prostaspheres formed by SP WPE1-NB26 cells (a) without or (b) after a treatment with exogenous EGF as compared to diffuse, abortive and very small aggregates formed by non-SP WPE1-NB26 cells are shown at a similar magnification of ×200. Moreover, the representative pictures of the prostaspheres formed by the SP WPE1-NB26 cell fraction (a) without or (b) after a treatment with exogenous EGF in the presence of different drugs, including a specific inhibitory agent of EGFR (gefitinib), PI3K (LY294002), pAkt (pAkt inhibitor VIII), NF-κB (partenolide), MIC-1 (anti-MIC-1 antibody) or docetaxel, are also shown at a similar magnification of ×200. The quantitative data of the number of prostaspheres formed by the SP WPE1-NB26 cell fraction (c) without or (d) after a treatment with exogenous EGF in the absence (control) or presence of different inhibitory agents obtained from at least 3 separate experiments are shown.
Mentions: The establishment of the functions of EGFR, PI3K/pAkt, NF-κB and MIC-1 for the self-renewal of the SP cell subpopulation versus the non-SP cell fraction isolated from the highly tumorigenic and invasive WPE1-NB26 cell line was done by performing prostasphere-forming assays in the absence or presence of specific inhibitory agents of these signaling elements in serum free-keratinocyte medium under an ultra-low attachment plate. As shown in Figure 6a, the results from prostasphere-forming assays have revealed that the SP cells from the WPE1-NB26 cell line were able to generate many dense prostaspheres with a large size in culture after 7 days in the absence of EGF. Moreover, the addition of exogenous EGF into culture medium significantly promoted the number and size of prostaspheres formed by SP WPE1-NB26 cells indicating an important role of EGF-EGFR system for the self-renewal of these immature PC cells (Figure 6b). In contrast, the non-SP WPE1-NB26 cell fraction after FAC sorting formed only a small number of diffuse, abortive and very small primary prostaspheres in the absence or presence of EGF, while no secondary prostasphere was formed at the second passage as compared to the high prostasphere-forming capacity of SP WPE1-NB26 cells that was retained upon serial passage (Figure 6a and b). We have also observed that the 10 µl/ml of the pre-immune rabbit serum was used as control has not significant effect on the prostasphere-forming ability of SP WPE1-NB26 cells as compared to 10 µl/ml anti-MIC-1 antibody (data not shown). Also, the treatment with docetaxel has not significant effect on the prostasphere-forming ability of SP WPE1-NB26 cells in the absence or presence of EGF (Figure 6a and b).

Bottom Line: The progression of prostate cancers (PCs) to locally invasive, androgen-independent and metastatic disease states is generally associated with treatment resistance and disease relapse.Moreover, the results have indicated that the EGF-EGFR signaling pathway can provide critical functions for the self-renewal of side population (SP) cells endowed with stem cell-like features from highly invasive WPE1-NB26 cells.Also, the targeting of these oncogenic products induced the caspase-dependent apoptosis in chemoresistant SP WPE1-NB26 cells and enhanced their sensibility to the cytotoxic effects induced by docetaxel.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America.

ABSTRACT
The progression of prostate cancers (PCs) to locally invasive, androgen-independent and metastatic disease states is generally associated with treatment resistance and disease relapse. The present study was undertaken to establish the possibility of using a combination of specific oncogenic products, including epidermal growth factor receptor (EGFR), pAkt, nuclear factor-kappaB (NF-κB) and macrophage inhibitory cytokine-1 (MIC-1) as biomarkers and therapeutic targets for optimizing the management of patients with localized PC at earlier disease stages. The immunohistochemical and immunofluorescence data have revealed that the expression levels of EGFR, Ser(473)-pAkt, NF-κB p65 and MIC-1 proteins were significantly enhanced in the same subset of 76 cases of prostatic adenocarcinoma specimens during the disease progression and these biomarkers were expressed in a small subpopulation of CD133(+) PC cells and the bulk tumor mass of CD133(-) PC cells. Importantly, all of these biomarkers were also overexpressed in 80-100% of 30 PC metastasis bone tissue specimens. Moreover, the results have indicated that the EGF-EGFR signaling pathway can provide critical functions for the self-renewal of side population (SP) cells endowed with stem cell-like features from highly invasive WPE1-NB26 cells. Of therapeutic interest, the targeting of EGFR, pAkt, NF-κB or MIC-1 was also effective at suppressing the basal and EGF-promoted prostasphere formation by SP WPE1-NB26 cells, inducing disintegration of SP cell-derived prostaspheres and decreasing the viability of SP and non-SP WPE1-NB26 cell fractions. Also, the targeting of these oncogenic products induced the caspase-dependent apoptosis in chemoresistant SP WPE1-NB26 cells and enhanced their sensibility to the cytotoxic effects induced by docetaxel. These findings suggest that the combined use of EGFR, pAkt, NF-κB and/or MIC-1 may represent promising strategies for improving the accuracy of current diagnostic and prognostic methods and efficacy of treatments of PC patients in considering the disease heterogeneity, thereby preventing PC progression to metastatic and lethal disease states.

Show MeSH
Related in: MedlinePlus