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Epidermal growth factor potentiates in vitro metastatic behaviour of human prostate cancer PC-3M cells: involvement of voltage-gated sodium channel.

Uysal-Onganer P, Djamgoz MB - Mol. Cancer (2007)

Bottom Line: The effects of EGF on VGSC expression in the highly metastatic human PCa PC-3M cell line, which was shown previously to express both functional VGSCs and EGF receptors, were investigated.EGF increased VGSC Nav1.7 (predominant isoform in PCa) mRNA and protein expressions.Co-application of the highly specific VGSC blocker tetrodotoxin (TTX) suppressed the effect of EGF on all three metastatic cell behaviours studied. 1) EGF has a major involvement in the upregulation of functional VGSC expression in human PCa PC-3M cells. (2) VGSC activity has a significant intermediary role in potentiating effect of EGF in human PCa.

View Article: PubMed Central - HTML - PubMed

Affiliation: Neuroscience Solutions to Cancer Research Group, Division of Cell and Molecular Biology, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London SW7 2AZ, UK. p.onganer@imperial.ac.uk

ABSTRACT

Background: Although a high level of functional voltage-gated sodium channel (VGSC) expression has been found in strongly metastatic human and rat prostate cancer (PCa) cells, the mechanism(s) responsible for the upregulation is unknown. The concentration of epidermal growth factor (EGF), a modulator of ion channels, in the body is highest in prostatic fluid. Thus, EGF could be involved in the VGSC upregulation in PCa. The effects of EGF on VGSC expression in the highly metastatic human PCa PC-3M cell line, which was shown previously to express both functional VGSCs and EGF receptors, were investigated. A quantitative approach, from gene level to cell behaviour, was used. mRNA levels were determined by real-time PCR. Protein expression was studied by Western blots and immunocytochemistry and digital image analysis. Functional assays involved measurements of transverse migration, endocytic membrane activity and Matrigel invasion.

Results: Exogenous EGF enhanced the cells' in vitro metastatic behaviours (migration, endocytosis and invasion). Endogenous EGF had a similar involvement. EGF increased VGSC Nav1.7 (predominant isoform in PCa) mRNA and protein expressions. Co-application of the highly specific VGSC blocker tetrodotoxin (TTX) suppressed the effect of EGF on all three metastatic cell behaviours studied.

Conclusion: 1) EGF has a major involvement in the upregulation of functional VGSC expression in human PCa PC-3M cells. (2) VGSC activity has a significant intermediary role in potentiating effect of EGF in human PCa.

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Related in: MedlinePlus

Effect of EGF on sub-cellular distribution of VGSC protein expression, determined by immunocytochemistry, confocal microscopy and digital imaging. VGSC expression was denoted by the fluorescence intensity (arbitrary units; AU) of the immunocytochemical label. (A) Typical profile of VGSC protein expression scanned across the cell. (B) Same as (A) after treatment with EGF (100 ng/ml) for 24 h. (C) Data quantified from profiles shown in (A) and (B) dividing the cellular cross-sections into cytoplasmic/internal ("INT") and plasma membrane ("PM") fractions, as described in the Methods. Each histobar denotes mean ± standard error (n = 18 cells from 3 separate experiments for each condition).
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Figure 5: Effect of EGF on sub-cellular distribution of VGSC protein expression, determined by immunocytochemistry, confocal microscopy and digital imaging. VGSC expression was denoted by the fluorescence intensity (arbitrary units; AU) of the immunocytochemical label. (A) Typical profile of VGSC protein expression scanned across the cell. (B) Same as (A) after treatment with EGF (100 ng/ml) for 24 h. (C) Data quantified from profiles shown in (A) and (B) dividing the cellular cross-sections into cytoplasmic/internal ("INT") and plasma membrane ("PM") fractions, as described in the Methods. Each histobar denotes mean ± standard error (n = 18 cells from 3 separate experiments for each condition).

Mentions: Finally, the possible effect of EGF on sub-cellular distribution of VGSC protein expression was investigated by immunocytochemistry, confocal microscopy and digital imaging (Fig. 5). This analysis showed that plasma membrane VGSC protein expression increased by 260 ± 3.2 % (p = 0.01; n = 18; Fig. 5C). In contrast, there was no significant change in the VGSC immunoreactivity of the intracellular compartment (Fig. 5C).


Epidermal growth factor potentiates in vitro metastatic behaviour of human prostate cancer PC-3M cells: involvement of voltage-gated sodium channel.

Uysal-Onganer P, Djamgoz MB - Mol. Cancer (2007)

Effect of EGF on sub-cellular distribution of VGSC protein expression, determined by immunocytochemistry, confocal microscopy and digital imaging. VGSC expression was denoted by the fluorescence intensity (arbitrary units; AU) of the immunocytochemical label. (A) Typical profile of VGSC protein expression scanned across the cell. (B) Same as (A) after treatment with EGF (100 ng/ml) for 24 h. (C) Data quantified from profiles shown in (A) and (B) dividing the cellular cross-sections into cytoplasmic/internal ("INT") and plasma membrane ("PM") fractions, as described in the Methods. Each histobar denotes mean ± standard error (n = 18 cells from 3 separate experiments for each condition).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2211503&req=5

Figure 5: Effect of EGF on sub-cellular distribution of VGSC protein expression, determined by immunocytochemistry, confocal microscopy and digital imaging. VGSC expression was denoted by the fluorescence intensity (arbitrary units; AU) of the immunocytochemical label. (A) Typical profile of VGSC protein expression scanned across the cell. (B) Same as (A) after treatment with EGF (100 ng/ml) for 24 h. (C) Data quantified from profiles shown in (A) and (B) dividing the cellular cross-sections into cytoplasmic/internal ("INT") and plasma membrane ("PM") fractions, as described in the Methods. Each histobar denotes mean ± standard error (n = 18 cells from 3 separate experiments for each condition).
Mentions: Finally, the possible effect of EGF on sub-cellular distribution of VGSC protein expression was investigated by immunocytochemistry, confocal microscopy and digital imaging (Fig. 5). This analysis showed that plasma membrane VGSC protein expression increased by 260 ± 3.2 % (p = 0.01; n = 18; Fig. 5C). In contrast, there was no significant change in the VGSC immunoreactivity of the intracellular compartment (Fig. 5C).

Bottom Line: The effects of EGF on VGSC expression in the highly metastatic human PCa PC-3M cell line, which was shown previously to express both functional VGSCs and EGF receptors, were investigated.EGF increased VGSC Nav1.7 (predominant isoform in PCa) mRNA and protein expressions.Co-application of the highly specific VGSC blocker tetrodotoxin (TTX) suppressed the effect of EGF on all three metastatic cell behaviours studied. 1) EGF has a major involvement in the upregulation of functional VGSC expression in human PCa PC-3M cells. (2) VGSC activity has a significant intermediary role in potentiating effect of EGF in human PCa.

View Article: PubMed Central - HTML - PubMed

Affiliation: Neuroscience Solutions to Cancer Research Group, Division of Cell and Molecular Biology, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London SW7 2AZ, UK. p.onganer@imperial.ac.uk

ABSTRACT

Background: Although a high level of functional voltage-gated sodium channel (VGSC) expression has been found in strongly metastatic human and rat prostate cancer (PCa) cells, the mechanism(s) responsible for the upregulation is unknown. The concentration of epidermal growth factor (EGF), a modulator of ion channels, in the body is highest in prostatic fluid. Thus, EGF could be involved in the VGSC upregulation in PCa. The effects of EGF on VGSC expression in the highly metastatic human PCa PC-3M cell line, which was shown previously to express both functional VGSCs and EGF receptors, were investigated. A quantitative approach, from gene level to cell behaviour, was used. mRNA levels were determined by real-time PCR. Protein expression was studied by Western blots and immunocytochemistry and digital image analysis. Functional assays involved measurements of transverse migration, endocytic membrane activity and Matrigel invasion.

Results: Exogenous EGF enhanced the cells' in vitro metastatic behaviours (migration, endocytosis and invasion). Endogenous EGF had a similar involvement. EGF increased VGSC Nav1.7 (predominant isoform in PCa) mRNA and protein expressions. Co-application of the highly specific VGSC blocker tetrodotoxin (TTX) suppressed the effect of EGF on all three metastatic cell behaviours studied.

Conclusion: 1) EGF has a major involvement in the upregulation of functional VGSC expression in human PCa PC-3M cells. (2) VGSC activity has a significant intermediary role in potentiating effect of EGF in human PCa.

Show MeSH
Related in: MedlinePlus