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Overexpression of Eag1 potassium channels in clinical tumours.

Hemmerlein B, Weseloh RM, Mello de Queiroz F, Knötgen H, Sánchez A, Rubio ME, Martin S, Schliephacke T, Jenke M - Mol. Cancer (2006)

Bottom Line: The use of reverse transcription real-time PCR and specifically generated monoclonal anti-Eag1 antibodies showed that expression of the channel is normally limited to specific areas of the brain and to restricted cell populations throughout the body.Inhibition of Eag1 expression in tumour cell lines reduced cell proliferation.Furthermore, as normal cells expressing Eag1 are either protected by the blood-brain barrier or represent the terminal stage of normal differentiation, Eag1 based therapies could produce only minor side effects.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pathology, Georg-August University, Göttingen, Germany. hemmer@med.uni-goettingen.de

ABSTRACT

Background: Certain types of potassium channels (known as Eag1, KCNH1, Kv10.1) are associated with the production of tumours in patients and in animals. We have now studied the expression pattern of the Eag1 channel in a large range of normal and tumour tissues from different collections utilising molecular biological and immunohistochemical techniques.

Results: The use of reverse transcription real-time PCR and specifically generated monoclonal anti-Eag1 antibodies showed that expression of the channel is normally limited to specific areas of the brain and to restricted cell populations throughout the body. Tumour samples, however, showed a significant overexpression of the channel with high frequency (up to 80% depending on the tissue source) regardless of the detection method (staining with either one of the antibodies, or detection of Eag1 RNA).

Conclusion: Inhibition of Eag1 expression in tumour cell lines reduced cell proliferation. Eag1 may therefore represent a promising target for the tailored treatment of human tumours. Furthermore, as normal cells expressing Eag1 are either protected by the blood-brain barrier or represent the terminal stage of normal differentiation, Eag1 based therapies could produce only minor side effects.

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Related in: MedlinePlus

Expression of Eag1 RNA in peripheral tissues is restricted. Real-time PCR records on cDNA from different human RNAs. The average fluorescence obtained in three experiments (± standard error) is plotted against cycle number. The dotted line indicates the threshold values used to determine positive signals. A clear signal can be detected after 21 cycles only in brain (red diamonds), while testis (dark green circles) and adrenal glands (light green triangles) required several more cycles of amplification for the signal to reach threshold. The rest of the tissues were negative. The Inset shows the control amplification obtained simultaneously on the same samples using the human transferrin receptor (TFR) as a template to demonstrate RNA integrity.
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Figure 2: Expression of Eag1 RNA in peripheral tissues is restricted. Real-time PCR records on cDNA from different human RNAs. The average fluorescence obtained in three experiments (± standard error) is plotted against cycle number. The dotted line indicates the threshold values used to determine positive signals. A clear signal can be detected after 21 cycles only in brain (red diamonds), while testis (dark green circles) and adrenal glands (light green triangles) required several more cycles of amplification for the signal to reach threshold. The rest of the tissues were negative. The Inset shows the control amplification obtained simultaneously on the same samples using the human transferrin receptor (TFR) as a template to demonstrate RNA integrity.

Mentions: In previous studies [6,11], dot blot, Northern blot and RT-PCR analyses all indicated that Eag1 is preferentially expressed in human brain. To confirm this finding and allow a more quantitative comparison, we performed real-time PCR on commercially available RNA extracted from several normal human tissues (Fig. 2). After normalising the RNA quality and tissue activity with respect to the transferrin receptor mRNA, our results confirmed the reported specific expression pattern of Eag1. The normalised levels of Eag1 expression obtained (brain = 1, see Materials and Methods) were: skeletal muscle 0.005, thymus 0.04, kidney 0.019, heart 0.003, spleen 0.0, trachea 0.046, mammary gland 0.028, adrenal gland 0.114, testis 0.124 and liver 0.0.


Overexpression of Eag1 potassium channels in clinical tumours.

Hemmerlein B, Weseloh RM, Mello de Queiroz F, Knötgen H, Sánchez A, Rubio ME, Martin S, Schliephacke T, Jenke M - Mol. Cancer (2006)

Expression of Eag1 RNA in peripheral tissues is restricted. Real-time PCR records on cDNA from different human RNAs. The average fluorescence obtained in three experiments (± standard error) is plotted against cycle number. The dotted line indicates the threshold values used to determine positive signals. A clear signal can be detected after 21 cycles only in brain (red diamonds), while testis (dark green circles) and adrenal glands (light green triangles) required several more cycles of amplification for the signal to reach threshold. The rest of the tissues were negative. The Inset shows the control amplification obtained simultaneously on the same samples using the human transferrin receptor (TFR) as a template to demonstrate RNA integrity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1621079&req=5

Figure 2: Expression of Eag1 RNA in peripheral tissues is restricted. Real-time PCR records on cDNA from different human RNAs. The average fluorescence obtained in three experiments (± standard error) is plotted against cycle number. The dotted line indicates the threshold values used to determine positive signals. A clear signal can be detected after 21 cycles only in brain (red diamonds), while testis (dark green circles) and adrenal glands (light green triangles) required several more cycles of amplification for the signal to reach threshold. The rest of the tissues were negative. The Inset shows the control amplification obtained simultaneously on the same samples using the human transferrin receptor (TFR) as a template to demonstrate RNA integrity.
Mentions: In previous studies [6,11], dot blot, Northern blot and RT-PCR analyses all indicated that Eag1 is preferentially expressed in human brain. To confirm this finding and allow a more quantitative comparison, we performed real-time PCR on commercially available RNA extracted from several normal human tissues (Fig. 2). After normalising the RNA quality and tissue activity with respect to the transferrin receptor mRNA, our results confirmed the reported specific expression pattern of Eag1. The normalised levels of Eag1 expression obtained (brain = 1, see Materials and Methods) were: skeletal muscle 0.005, thymus 0.04, kidney 0.019, heart 0.003, spleen 0.0, trachea 0.046, mammary gland 0.028, adrenal gland 0.114, testis 0.124 and liver 0.0.

Bottom Line: The use of reverse transcription real-time PCR and specifically generated monoclonal anti-Eag1 antibodies showed that expression of the channel is normally limited to specific areas of the brain and to restricted cell populations throughout the body.Inhibition of Eag1 expression in tumour cell lines reduced cell proliferation.Furthermore, as normal cells expressing Eag1 are either protected by the blood-brain barrier or represent the terminal stage of normal differentiation, Eag1 based therapies could produce only minor side effects.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pathology, Georg-August University, Göttingen, Germany. hemmer@med.uni-goettingen.de

ABSTRACT

Background: Certain types of potassium channels (known as Eag1, KCNH1, Kv10.1) are associated with the production of tumours in patients and in animals. We have now studied the expression pattern of the Eag1 channel in a large range of normal and tumour tissues from different collections utilising molecular biological and immunohistochemical techniques.

Results: The use of reverse transcription real-time PCR and specifically generated monoclonal anti-Eag1 antibodies showed that expression of the channel is normally limited to specific areas of the brain and to restricted cell populations throughout the body. Tumour samples, however, showed a significant overexpression of the channel with high frequency (up to 80% depending on the tissue source) regardless of the detection method (staining with either one of the antibodies, or detection of Eag1 RNA).

Conclusion: Inhibition of Eag1 expression in tumour cell lines reduced cell proliferation. Eag1 may therefore represent a promising target for the tailored treatment of human tumours. Furthermore, as normal cells expressing Eag1 are either protected by the blood-brain barrier or represent the terminal stage of normal differentiation, Eag1 based therapies could produce only minor side effects.

Show MeSH
Related in: MedlinePlus