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Ovarian cancer stem-like cells show induced translineage-differentiation capacity and are suppressed by alkaline phosphatase inhibitor.

Liu KC, Yo YT, Huang RL, Wang YC, Liao YP, Huang TS, Chao TK, Lin CK, Weng SJ, Ma KH, Chang CC, Yu MH, Lai HC - Oncotarget (2013)

Bottom Line: Alkaline phosphatase (ALP) was highly expressed in SR1 spheroids, decreased in SR2 spheroids, and was absent in differentiated progenies in accordance with the loss of stemness properties.We verified that ALP can be a marker for ovarian CSLCs, and patients with greater ALP expression is related to advanced clinical stages and have a higher risk of recurrence and lower survival rate.In summary, this research provides a plastic ovarian cancer stem cell model and a new understanding of the cross-link between stem cells and cancers.This results show that ovarian CSLCs can be suppressed by levamisole.

View Article: PubMed Central - PubMed

Affiliation: Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.

ABSTRACT
Spheroid formation is one property of stem cells-such as embryo-derived or neural stem cells-that has been used for the enrichment of cancer stem-like cells (CSLCs). However, it is unclear whether CSLC-derived spheroids are heterogeneous or whether they share common embryonic stemness properties. Understanding these features might lead to novel therapeutic approaches. Ovarian carcinoma is a deadly disease of women. We identified two types of spheroids (SR1 and SR2) from ovarian cancer cell lines and patients' specimens according to their morphology. Both types expressed stemness markers and could self-renew and initiate tumors when a low number of cells were used. Only SR1 could differentiate into multiple-lineage cell types under specific induction conditions. SR1 spheroids could differentiate to SR2 spheroids through epithelial-mesenchymal transition. Alkaline phosphatase (ALP) was highly expressed in SR1 spheroids, decreased in SR2 spheroids, and was absent in differentiated progenies in accordance with the loss of stemness properties. We verified that ALP can be a marker for ovarian CSLCs, and patients with greater ALP expression is related to advanced clinical stages and have a higher risk of recurrence and lower survival rate. The ALP inhibitor, levamisole, disrupted the self-renewal of ovarian CSLCs in vitro and tumor growth in vivo. In summary, this research provides a plastic ovarian cancer stem cell model and a new understanding of the cross-link between stem cells and cancers.This results show that ovarian CSLCs can be suppressed by levamisole. Our findings demonstrated that some ovarian CSLCs may restore ALP activity, and this suggests that inhibition of ALP activity may present a new opportunity for treatment of ovarian cancer.

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Morphology and stemness properties of ovarian cancer cell spheroids(A) Two different types of spheroids (SR1 and SR2) were enriched in various ovarian cancer cell lines. (B, C) The CD44+CD133+ signal increased in both SR1 and SR2 cells derived from SKOV3 and A2780 cells, whereas CD44+CD133− and CD44−CD133+ were expressed in the original SKOV3 and A2780 cells, respectively. The expression of CD133 and OCT4 was higher in SKOV3SR1 cells (B, D), whereas the expression of OCT4 and SOX2 was higher in A2780SR2 cells (C, E). (F, G) Expression of CD133 and CD44 was compared between adhesive SKOV3-derived SR1 and the original cells. (F) After adhesive culture for 24 hours, the expression of CD133 decreased in adhesive SKOV3-derived SR1 from the center site to the periphery, but CD133 in scattered SR1 cells was still detectable in the periphery. (G) Almost all SKOV3 original cells expressed CD44 but not CD133.
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Figure 1: Morphology and stemness properties of ovarian cancer cell spheroids(A) Two different types of spheroids (SR1 and SR2) were enriched in various ovarian cancer cell lines. (B, C) The CD44+CD133+ signal increased in both SR1 and SR2 cells derived from SKOV3 and A2780 cells, whereas CD44+CD133− and CD44−CD133+ were expressed in the original SKOV3 and A2780 cells, respectively. The expression of CD133 and OCT4 was higher in SKOV3SR1 cells (B, D), whereas the expression of OCT4 and SOX2 was higher in A2780SR2 cells (C, E). (F, G) Expression of CD133 and CD44 was compared between adhesive SKOV3-derived SR1 and the original cells. (F) After adhesive culture for 24 hours, the expression of CD133 decreased in adhesive SKOV3-derived SR1 from the center site to the periphery, but CD133 in scattered SR1 cells was still detectable in the periphery. (G) Almost all SKOV3 original cells expressed CD44 but not CD133.

Mentions: We cultivated four human epithelial ovarian cancer (EOC) cell lines using stem cell suspended-culture conditions [23], which produced two distinctive types of spheres (SR1 and SR2) (Figure 1A). Each cell line preferred to develop into different types of spheres; the EOC cell lines SKOV3 and OVCAR-3 generated more SR1, A2780 cells formed more SR2, and CP70 cells could develop into both SR1 and SR2 simultaneously. SR1 exhibited a ball shape with a smooth surface, and SR2 was irregular in shape with a morula-like surface (Figure 1A). The morphology of SR1 and SR2 also differed under adhesion culture conditions (Supplementary Information, Figure S1A), For the assessment of stemness, flow cytometry was used to detect stem-associated markers in the two types of spheroids; the CD44+CD133+ population increased significantly in SKOV3SR1 and A2780SR2 cells, and the CD44−CD133+ population also increased in A2780SR2 cells (Figure 1B and 1C). Expression of OCT4 and SOX2 increased in SKOV3SR1 and A2780SR2 cells but with different magnitude of the change (Figure 1D and 1E). Immunocytochemistry staining confirmed that CD133 expression (Figure 1F and 1G) decreased significantly after induction of SKOV3SR1 differentiation.


Ovarian cancer stem-like cells show induced translineage-differentiation capacity and are suppressed by alkaline phosphatase inhibitor.

Liu KC, Yo YT, Huang RL, Wang YC, Liao YP, Huang TS, Chao TK, Lin CK, Weng SJ, Ma KH, Chang CC, Yu MH, Lai HC - Oncotarget (2013)

Morphology and stemness properties of ovarian cancer cell spheroids(A) Two different types of spheroids (SR1 and SR2) were enriched in various ovarian cancer cell lines. (B, C) The CD44+CD133+ signal increased in both SR1 and SR2 cells derived from SKOV3 and A2780 cells, whereas CD44+CD133− and CD44−CD133+ were expressed in the original SKOV3 and A2780 cells, respectively. The expression of CD133 and OCT4 was higher in SKOV3SR1 cells (B, D), whereas the expression of OCT4 and SOX2 was higher in A2780SR2 cells (C, E). (F, G) Expression of CD133 and CD44 was compared between adhesive SKOV3-derived SR1 and the original cells. (F) After adhesive culture for 24 hours, the expression of CD133 decreased in adhesive SKOV3-derived SR1 from the center site to the periphery, but CD133 in scattered SR1 cells was still detectable in the periphery. (G) Almost all SKOV3 original cells expressed CD44 but not CD133.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3926833&req=5

Figure 1: Morphology and stemness properties of ovarian cancer cell spheroids(A) Two different types of spheroids (SR1 and SR2) were enriched in various ovarian cancer cell lines. (B, C) The CD44+CD133+ signal increased in both SR1 and SR2 cells derived from SKOV3 and A2780 cells, whereas CD44+CD133− and CD44−CD133+ were expressed in the original SKOV3 and A2780 cells, respectively. The expression of CD133 and OCT4 was higher in SKOV3SR1 cells (B, D), whereas the expression of OCT4 and SOX2 was higher in A2780SR2 cells (C, E). (F, G) Expression of CD133 and CD44 was compared between adhesive SKOV3-derived SR1 and the original cells. (F) After adhesive culture for 24 hours, the expression of CD133 decreased in adhesive SKOV3-derived SR1 from the center site to the periphery, but CD133 in scattered SR1 cells was still detectable in the periphery. (G) Almost all SKOV3 original cells expressed CD44 but not CD133.
Mentions: We cultivated four human epithelial ovarian cancer (EOC) cell lines using stem cell suspended-culture conditions [23], which produced two distinctive types of spheres (SR1 and SR2) (Figure 1A). Each cell line preferred to develop into different types of spheres; the EOC cell lines SKOV3 and OVCAR-3 generated more SR1, A2780 cells formed more SR2, and CP70 cells could develop into both SR1 and SR2 simultaneously. SR1 exhibited a ball shape with a smooth surface, and SR2 was irregular in shape with a morula-like surface (Figure 1A). The morphology of SR1 and SR2 also differed under adhesion culture conditions (Supplementary Information, Figure S1A), For the assessment of stemness, flow cytometry was used to detect stem-associated markers in the two types of spheroids; the CD44+CD133+ population increased significantly in SKOV3SR1 and A2780SR2 cells, and the CD44−CD133+ population also increased in A2780SR2 cells (Figure 1B and 1C). Expression of OCT4 and SOX2 increased in SKOV3SR1 and A2780SR2 cells but with different magnitude of the change (Figure 1D and 1E). Immunocytochemistry staining confirmed that CD133 expression (Figure 1F and 1G) decreased significantly after induction of SKOV3SR1 differentiation.

Bottom Line: Alkaline phosphatase (ALP) was highly expressed in SR1 spheroids, decreased in SR2 spheroids, and was absent in differentiated progenies in accordance with the loss of stemness properties.We verified that ALP can be a marker for ovarian CSLCs, and patients with greater ALP expression is related to advanced clinical stages and have a higher risk of recurrence and lower survival rate.In summary, this research provides a plastic ovarian cancer stem cell model and a new understanding of the cross-link between stem cells and cancers.This results show that ovarian CSLCs can be suppressed by levamisole.

View Article: PubMed Central - PubMed

Affiliation: Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.

ABSTRACT
Spheroid formation is one property of stem cells-such as embryo-derived or neural stem cells-that has been used for the enrichment of cancer stem-like cells (CSLCs). However, it is unclear whether CSLC-derived spheroids are heterogeneous or whether they share common embryonic stemness properties. Understanding these features might lead to novel therapeutic approaches. Ovarian carcinoma is a deadly disease of women. We identified two types of spheroids (SR1 and SR2) from ovarian cancer cell lines and patients' specimens according to their morphology. Both types expressed stemness markers and could self-renew and initiate tumors when a low number of cells were used. Only SR1 could differentiate into multiple-lineage cell types under specific induction conditions. SR1 spheroids could differentiate to SR2 spheroids through epithelial-mesenchymal transition. Alkaline phosphatase (ALP) was highly expressed in SR1 spheroids, decreased in SR2 spheroids, and was absent in differentiated progenies in accordance with the loss of stemness properties. We verified that ALP can be a marker for ovarian CSLCs, and patients with greater ALP expression is related to advanced clinical stages and have a higher risk of recurrence and lower survival rate. The ALP inhibitor, levamisole, disrupted the self-renewal of ovarian CSLCs in vitro and tumor growth in vivo. In summary, this research provides a plastic ovarian cancer stem cell model and a new understanding of the cross-link between stem cells and cancers.This results show that ovarian CSLCs can be suppressed by levamisole. Our findings demonstrated that some ovarian CSLCs may restore ALP activity, and this suggests that inhibition of ALP activity may present a new opportunity for treatment of ovarian cancer.

Show MeSH
Related in: MedlinePlus