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TGF-{beta} maintains dormancy of prostatic stem cells in the proximal region of ducts.

Salm SN, Burger PE, Coetzee S, Goto K, Moscatelli D, Wilson EL - J. Cell Biol. (2005)

Bottom Line: This conclusion is supported by the observations showing that high levels of TGF-beta signaling are present in the quiescent proximal region of ducts in an androgen-replete animal and that cells in this region overexpress Bcl-2, which protects them from apoptosis.A physiological TGF-beta signaling gradient (high proximally and low distally) and its functional correlates are restored after androgen replenishment.In addition to highlighting the regulatory role of androgens and TGF-beta, these findings may have important implications for the deregulation of the stem cell compartment in the etiology of proliferative prostatic diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.

ABSTRACT
We have previously shown that prostatic stem cells are located in the proximal region of mouse prostatic ducts. Here, we show that this region responds differently to transforming growth factor (TGF)-beta than the distal ductal region and that under physiological conditions androgens and TGF-beta are crucial overall regulators of prostatic tissue homeostasis. This conclusion is supported by the observations showing that high levels of TGF-beta signaling are present in the quiescent proximal region of ducts in an androgen-replete animal and that cells in this region overexpress Bcl-2, which protects them from apoptosis. Moreover, androgen ablation reverses the proximal-distal TGF-beta signaling gradient, leading to an increase in TGF-beta signaling in the unprotected distal region (low Bcl-2 expression). This reversal of TGF-beta-mediated signaling accompanies apoptosis of cells in the distal region and gland involution after androgen withdrawal. A physiological TGF-beta signaling gradient (high proximally and low distally) and its functional correlates are restored after androgen replenishment. In addition to highlighting the regulatory role of androgens and TGF-beta, these findings may have important implications for the deregulation of the stem cell compartment in the etiology of proliferative prostatic diseases.

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Proximal cells are more resistant to the differentiating-inducing effects of TGF-β than cells from the remaining regions of ducts. (A) Cells from the proximal and remaining ductal regions (2,000 cells/collagen-coated 8-well chamber slide) were cultured for 5–7 d and TGF-β (0.1 ng/ml) was added for 48 h after which colonies of >100 cells were counted and examined for evidence of basal and luminal cytokeratins. The data are plotted as the colony type (basal, luminal, or intermediate) as a percentage of the total number of colonies and are the average of four pooled experiments. *, 1.2-fold, P > 0.05 NS; **, 1.8-fold, P < 0.0001; ***, 4.7-fold, P < 0.001. (B) Colonies were examined immunohistochemically using antibodies to basal or luminal cytokeratins and appropriate Alexa Fluor 594 or 488 secondary fluorescent antibodies to determine those colonies that were comprised of basal (red), intermediate (both basal and luminal), or luminal (green) cells. Bars, 50 μm.
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fig6: Proximal cells are more resistant to the differentiating-inducing effects of TGF-β than cells from the remaining regions of ducts. (A) Cells from the proximal and remaining ductal regions (2,000 cells/collagen-coated 8-well chamber slide) were cultured for 5–7 d and TGF-β (0.1 ng/ml) was added for 48 h after which colonies of >100 cells were counted and examined for evidence of basal and luminal cytokeratins. The data are plotted as the colony type (basal, luminal, or intermediate) as a percentage of the total number of colonies and are the average of four pooled experiments. *, 1.2-fold, P > 0.05 NS; **, 1.8-fold, P < 0.0001; ***, 4.7-fold, P < 0.001. (B) Colonies were examined immunohistochemically using antibodies to basal or luminal cytokeratins and appropriate Alexa Fluor 594 or 488 secondary fluorescent antibodies to determine those colonies that were comprised of basal (red), intermediate (both basal and luminal), or luminal (green) cells. Bars, 50 μm.

Mentions: TGF-β has been shown to induce the differentiation of a rat basal cell line to luminal cells (Danielpour, 1999). Therefore, we determined the effects of TGF-β on the colony composition of cells isolated from the proximal and remaining ductal regions. As TGF-β inhibits cell growth, cells were initially cultured in the absence of TGF-β and, once clonal growth was established, TGF-β (0.1 ng/ml) was added for the final 48 h of culture and its effect on the composition of colonies (basal, luminal, and intermediate [cells containing both basal and luminal cytokeratins]) was determined. The addition of TGF-β to colonies arising from proximal cells resulted in a twofold decrease (P < 0.001) in the incidence of basal colonies and 2.1- and 2.5-fold increases in luminal and intermediate colonies, respectively (P < 0.002 and P < 0.003; Fig. 6 and Tables I and II). Colonies arising from cells isolated from the remaining ductal regions were more sensitive to TGF-β as an eightfold decrease in basal colonies was noted (P < 0.0001) concomitant with a 2.2- and a threefold increase in luminal and intermediate colonies, respectively (P < 0.001 and P < 0.02; Fig. 6 and Tables I and II). Significantly more of the colonies arising from proximal cells had a basal phenotype (35.9 ± 18.9%) after TGF-β addition than those colonies that grew from cells isolated from the remaining ductal regions (7.6 ± 7.9%; P < 0.001). Similar significant differences were noted in the incidence of luminal colonies after TGF-β treatment with cells isolated from the remaining ductal regions having 1.8-fold more luminal colonies than proximal cells (P < 0.0001; Fig. 6 and Tables I and II). These data show that TGF-β induces differentiation of basal cells to luminal cells and that cells isolated from the proximal region are more resistant to the differentiation-inducing effects of TGF-β than cells from the remaining regions of ducts.


TGF-{beta} maintains dormancy of prostatic stem cells in the proximal region of ducts.

Salm SN, Burger PE, Coetzee S, Goto K, Moscatelli D, Wilson EL - J. Cell Biol. (2005)

Proximal cells are more resistant to the differentiating-inducing effects of TGF-β than cells from the remaining regions of ducts. (A) Cells from the proximal and remaining ductal regions (2,000 cells/collagen-coated 8-well chamber slide) were cultured for 5–7 d and TGF-β (0.1 ng/ml) was added for 48 h after which colonies of >100 cells were counted and examined for evidence of basal and luminal cytokeratins. The data are plotted as the colony type (basal, luminal, or intermediate) as a percentage of the total number of colonies and are the average of four pooled experiments. *, 1.2-fold, P > 0.05 NS; **, 1.8-fold, P < 0.0001; ***, 4.7-fold, P < 0.001. (B) Colonies were examined immunohistochemically using antibodies to basal or luminal cytokeratins and appropriate Alexa Fluor 594 or 488 secondary fluorescent antibodies to determine those colonies that were comprised of basal (red), intermediate (both basal and luminal), or luminal (green) cells. Bars, 50 μm.
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fig6: Proximal cells are more resistant to the differentiating-inducing effects of TGF-β than cells from the remaining regions of ducts. (A) Cells from the proximal and remaining ductal regions (2,000 cells/collagen-coated 8-well chamber slide) were cultured for 5–7 d and TGF-β (0.1 ng/ml) was added for 48 h after which colonies of >100 cells were counted and examined for evidence of basal and luminal cytokeratins. The data are plotted as the colony type (basal, luminal, or intermediate) as a percentage of the total number of colonies and are the average of four pooled experiments. *, 1.2-fold, P > 0.05 NS; **, 1.8-fold, P < 0.0001; ***, 4.7-fold, P < 0.001. (B) Colonies were examined immunohistochemically using antibodies to basal or luminal cytokeratins and appropriate Alexa Fluor 594 or 488 secondary fluorescent antibodies to determine those colonies that were comprised of basal (red), intermediate (both basal and luminal), or luminal (green) cells. Bars, 50 μm.
Mentions: TGF-β has been shown to induce the differentiation of a rat basal cell line to luminal cells (Danielpour, 1999). Therefore, we determined the effects of TGF-β on the colony composition of cells isolated from the proximal and remaining ductal regions. As TGF-β inhibits cell growth, cells were initially cultured in the absence of TGF-β and, once clonal growth was established, TGF-β (0.1 ng/ml) was added for the final 48 h of culture and its effect on the composition of colonies (basal, luminal, and intermediate [cells containing both basal and luminal cytokeratins]) was determined. The addition of TGF-β to colonies arising from proximal cells resulted in a twofold decrease (P < 0.001) in the incidence of basal colonies and 2.1- and 2.5-fold increases in luminal and intermediate colonies, respectively (P < 0.002 and P < 0.003; Fig. 6 and Tables I and II). Colonies arising from cells isolated from the remaining ductal regions were more sensitive to TGF-β as an eightfold decrease in basal colonies was noted (P < 0.0001) concomitant with a 2.2- and a threefold increase in luminal and intermediate colonies, respectively (P < 0.001 and P < 0.02; Fig. 6 and Tables I and II). Significantly more of the colonies arising from proximal cells had a basal phenotype (35.9 ± 18.9%) after TGF-β addition than those colonies that grew from cells isolated from the remaining ductal regions (7.6 ± 7.9%; P < 0.001). Similar significant differences were noted in the incidence of luminal colonies after TGF-β treatment with cells isolated from the remaining ductal regions having 1.8-fold more luminal colonies than proximal cells (P < 0.0001; Fig. 6 and Tables I and II). These data show that TGF-β induces differentiation of basal cells to luminal cells and that cells isolated from the proximal region are more resistant to the differentiation-inducing effects of TGF-β than cells from the remaining regions of ducts.

Bottom Line: This conclusion is supported by the observations showing that high levels of TGF-beta signaling are present in the quiescent proximal region of ducts in an androgen-replete animal and that cells in this region overexpress Bcl-2, which protects them from apoptosis.A physiological TGF-beta signaling gradient (high proximally and low distally) and its functional correlates are restored after androgen replenishment.In addition to highlighting the regulatory role of androgens and TGF-beta, these findings may have important implications for the deregulation of the stem cell compartment in the etiology of proliferative prostatic diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.

ABSTRACT
We have previously shown that prostatic stem cells are located in the proximal region of mouse prostatic ducts. Here, we show that this region responds differently to transforming growth factor (TGF)-beta than the distal ductal region and that under physiological conditions androgens and TGF-beta are crucial overall regulators of prostatic tissue homeostasis. This conclusion is supported by the observations showing that high levels of TGF-beta signaling are present in the quiescent proximal region of ducts in an androgen-replete animal and that cells in this region overexpress Bcl-2, which protects them from apoptosis. Moreover, androgen ablation reverses the proximal-distal TGF-beta signaling gradient, leading to an increase in TGF-beta signaling in the unprotected distal region (low Bcl-2 expression). This reversal of TGF-beta-mediated signaling accompanies apoptosis of cells in the distal region and gland involution after androgen withdrawal. A physiological TGF-beta signaling gradient (high proximally and low distally) and its functional correlates are restored after androgen replenishment. In addition to highlighting the regulatory role of androgens and TGF-beta, these findings may have important implications for the deregulation of the stem cell compartment in the etiology of proliferative prostatic diseases.

Show MeSH
Related in: MedlinePlus