In der Wissenschaft aktuell vom 17.1.
berichtet Joachim Czichos von einem Tierversuch, bei dem Krebsstammzellen von Prostatatumoren gehemmt werden konnten durch Gabe von Mikro-RNA, genauer miR-34a.
miR-34a sorgt für die Hemmung von CD44, was die Produktion von funktionierenden Krebsstammzellen, die PCa-Tumore wieder erzeugen können, hemmt. Die Hemmung vom CD44 ist das Entscheidende, auch wenns anders als mit miR-34 gelingt, ist der Effekt dergleiche.
Unten der Abstract.
Also ein Ansatz, gg. die eigentlich gefährlichen PCa-Zellen vorzugehen.
Es gibt eine Reihe weiterer Oberflächenmarker, an denen PCa-Stammzellen zu erkennen sind, u.a. CD133.
Hier hatte Forscher aus Hongkong kürzlich eine Hemmung von Stammzellen erreicht mit Gamma-Tocotrienol.
Dazu der Abstract auch unten reinkopiert.
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Nat Med. 2011 Jan 16. [Epub ahead of print]
The microRNA miR-34a inhibits prostate cancer stem cells and metastasis by directly repressing CD44.
Liu C, Kelnar K, Liu B, Chen X, Calhoun-Davis T, Li H, Patrawala L, Yan H, Jeter C, Honorio S, Wiggins JF, Bader AG, Fagin R, Brown D, Tang DG.
[1] Department of Molecular Carcinogenesis, the University of Texas M.D. Anderson Cancer Center, Science Park, Smithville, Texas, USA. [2] Program in Molecular Carcinogenesis, The University of Texas Graduate School of Biomedical Sciences (GSBS), Houston, Texas, USA.
Abstract
Cancer stem cells (CSCs), or tumor-initiating cells, are involved in tumor progression and metastasis. MicroRNAs (miRNAs) regulate both normal stem cells and CSCs, and dysregulation of miRNAs has been implicated in tumorigenesis. CSCs in many tumors-including cancers of the breast, pancreas, head and neck, colon, small intestine, liver, stomach, bladder and ovary-have been identified using the adhesion molecule CD44, either individually or in combination with other marker(s). Prostate CSCs with enhanced clonogenic and tumor-initiating and metastatic capacities are enriched in the CD44(+) cell population, but whether miRNAs regulate CD44(+) prostate cancer cells and prostate cancer metastasis remains unclear. Here we show, through expression analysis, that miR-34a, a p53 target, was underexpressed in CD44(+) prostate cancer cells purified from xenograft and primary tumors. Enforced expression of miR-34a in bulk or purified CD44(+) prostate cancer cells inhibited clonogenic expansion, tumor regeneration, and metastasis. In contrast, expression of miR-34a antagomirs in CD44(-) prostate cancer cells promoted tumor development and metastasis. Systemically delivered miR-34a inhibited prostate cancer metastasis and extended survival of tumor-bearing mice. We identified and validated CD44 as a direct and functional target of miR-34a and found that CD44 knockdown phenocopied miR-34a overexpression in inhibiting prostate cancer regeneration and metastasis. Our study shows that miR-34a is a key negative regulator of CD44(+) prostate cancer cells and establishes a strong rationale for developing miR-34a as a novel therapeutic agent against prostate CSCs.
PMID: 21240262 [PubMed - as supplied by publisher]
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International Journal of Cancer
Gamma-tocotrienol as an effective agent in targeting prostate cancer stem cell-like population
Sze Ue Luk1, Wei Ney Yap2,†, Yung-Tuen Chiu1, Davy TW Lee1, Stephanie Ma3, Terence Kin Wah Lee3, Raja S Vasireddy4, Yong-Chuan Wong1, Yick Pang Ching1, Colleen Nelson4, Yee Leng Yap2,*,†, Ming-Tat Ling4,*,‡
Department of Anatomy, Faculty of Medicine, the University of Hong Kong, Hong Kong, SAR, China.
Article first published online: 8 JUL 2010 DOI: 10.1002/ijc.25546
Keywords: Tocotrienol;prostate cancer;stem cell;vitamin E
Abstract
Emerging evidence supports that prostate cancer originates from a rare subpopulation of cells, namely prostate cancer stem cells (CSCs).
Conventional therapies for prostate cancer are believed to mainly target the majority of differentiated tumor cells but spare CSCs, which may account for the subsequent disease relapse after treatment. Therefore, successful elimination of CSCs may be an effective strategy to achieve complete remission from this disease.
Gamma-tocotrienols (γ-T3) is one of the vitamin-E constituents, which have been shown to have anticancer effects against a wide range of human cancers.
Recently, we have reported that γ-T3 treatment not only inhibits prostate cancer cell invasion but also sensitizes the cells to docetaxel-induced apoptosis, suggesting that γ-T3 may be an effective therapeutic agent against advanced stage prostate cancer.
Here, we demonstrate for the first time that γ-T3 can downregulate the expression of prostate CSC markers (CD133/CD44) in androgen-independent prostate cancer cell lines (PC-3 and DU145), as evident from Western blotting analysis. Meanwhile, the spheroid formation ability of the prostate cancer cells was significantly hampered by γ-T3 treatment. In addition, pretreatment of PC-3 cells with γ-T3 was found to suppress tumor initiation ability of the cells.
More importantly, although CD133-enriched PC-3 cells were highly resistant to docetaxel treatment, these cells were as sensitive to γ-T3 treatment as the CD133-depleted population.
Our data suggest that γ-T3 may be an effective agent in targeting prostate CSCs, which may account for its anticancer and chemosensitizing effects reported in previous studies.
berichtet Joachim Czichos von einem Tierversuch, bei dem Krebsstammzellen von Prostatatumoren gehemmt werden konnten durch Gabe von Mikro-RNA, genauer miR-34a.
"Viele Krebsstammzellen bilden das Oberflächen-Adhäsionsprotein CD44 im Überschuss. Dieses
Protein spielt eine Rolle bei der Förderung des Tumorwachstums und vor allem bei Krebsmetastasen", sagt Dean Tang vom M. D. Anderson-Krebszentrum der University of Texas.
Protein spielt eine Rolle bei der Förderung des Tumorwachstums und vor allem bei Krebsmetastasen", sagt Dean Tang vom M. D. Anderson-Krebszentrum der University of Texas.
Unten der Abstract.
Also ein Ansatz, gg. die eigentlich gefährlichen PCa-Zellen vorzugehen.
Es gibt eine Reihe weiterer Oberflächenmarker, an denen PCa-Stammzellen zu erkennen sind, u.a. CD133.
Hier hatte Forscher aus Hongkong kürzlich eine Hemmung von Stammzellen erreicht mit Gamma-Tocotrienol.
Dazu der Abstract auch unten reinkopiert.
++++++++++++++++++++++++++++++++++++
Nat Med. 2011 Jan 16. [Epub ahead of print]
The microRNA miR-34a inhibits prostate cancer stem cells and metastasis by directly repressing CD44.
Liu C, Kelnar K, Liu B, Chen X, Calhoun-Davis T, Li H, Patrawala L, Yan H, Jeter C, Honorio S, Wiggins JF, Bader AG, Fagin R, Brown D, Tang DG.
[1] Department of Molecular Carcinogenesis, the University of Texas M.D. Anderson Cancer Center, Science Park, Smithville, Texas, USA. [2] Program in Molecular Carcinogenesis, The University of Texas Graduate School of Biomedical Sciences (GSBS), Houston, Texas, USA.
Abstract
Cancer stem cells (CSCs), or tumor-initiating cells, are involved in tumor progression and metastasis. MicroRNAs (miRNAs) regulate both normal stem cells and CSCs, and dysregulation of miRNAs has been implicated in tumorigenesis. CSCs in many tumors-including cancers of the breast, pancreas, head and neck, colon, small intestine, liver, stomach, bladder and ovary-have been identified using the adhesion molecule CD44, either individually or in combination with other marker(s). Prostate CSCs with enhanced clonogenic and tumor-initiating and metastatic capacities are enriched in the CD44(+) cell population, but whether miRNAs regulate CD44(+) prostate cancer cells and prostate cancer metastasis remains unclear. Here we show, through expression analysis, that miR-34a, a p53 target, was underexpressed in CD44(+) prostate cancer cells purified from xenograft and primary tumors. Enforced expression of miR-34a in bulk or purified CD44(+) prostate cancer cells inhibited clonogenic expansion, tumor regeneration, and metastasis. In contrast, expression of miR-34a antagomirs in CD44(-) prostate cancer cells promoted tumor development and metastasis. Systemically delivered miR-34a inhibited prostate cancer metastasis and extended survival of tumor-bearing mice. We identified and validated CD44 as a direct and functional target of miR-34a and found that CD44 knockdown phenocopied miR-34a overexpression in inhibiting prostate cancer regeneration and metastasis. Our study shows that miR-34a is a key negative regulator of CD44(+) prostate cancer cells and establishes a strong rationale for developing miR-34a as a novel therapeutic agent against prostate CSCs.
PMID: 21240262 [PubMed - as supplied by publisher]
+++++++++++++++++++++++++++++++++++++++++++++++
International Journal of Cancer
Gamma-tocotrienol as an effective agent in targeting prostate cancer stem cell-like population
Sze Ue Luk1, Wei Ney Yap2,†, Yung-Tuen Chiu1, Davy TW Lee1, Stephanie Ma3, Terence Kin Wah Lee3, Raja S Vasireddy4, Yong-Chuan Wong1, Yick Pang Ching1, Colleen Nelson4, Yee Leng Yap2,*,†, Ming-Tat Ling4,*,‡
Department of Anatomy, Faculty of Medicine, the University of Hong Kong, Hong Kong, SAR, China.
Article first published online: 8 JUL 2010 DOI: 10.1002/ijc.25546
Keywords: Tocotrienol;prostate cancer;stem cell;vitamin E
Abstract
Emerging evidence supports that prostate cancer originates from a rare subpopulation of cells, namely prostate cancer stem cells (CSCs).
Conventional therapies for prostate cancer are believed to mainly target the majority of differentiated tumor cells but spare CSCs, which may account for the subsequent disease relapse after treatment. Therefore, successful elimination of CSCs may be an effective strategy to achieve complete remission from this disease.
Gamma-tocotrienols (γ-T3) is one of the vitamin-E constituents, which have been shown to have anticancer effects against a wide range of human cancers.
Recently, we have reported that γ-T3 treatment not only inhibits prostate cancer cell invasion but also sensitizes the cells to docetaxel-induced apoptosis, suggesting that γ-T3 may be an effective therapeutic agent against advanced stage prostate cancer.
Here, we demonstrate for the first time that γ-T3 can downregulate the expression of prostate CSC markers (CD133/CD44) in androgen-independent prostate cancer cell lines (PC-3 and DU145), as evident from Western blotting analysis. Meanwhile, the spheroid formation ability of the prostate cancer cells was significantly hampered by γ-T3 treatment. In addition, pretreatment of PC-3 cells with γ-T3 was found to suppress tumor initiation ability of the cells.
More importantly, although CD133-enriched PC-3 cells were highly resistant to docetaxel treatment, these cells were as sensitive to γ-T3 treatment as the CD133-depleted population.
Our data suggest that γ-T3 may be an effective agent in targeting prostate CSCs, which may account for its anticancer and chemosensitizing effects reported in previous studies.
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