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Crosstalk between Desmoglein 2 and Patched 1 accelerates chemical-induced skin tumorigenesis.

Brennan-Crispi DM, Hossain C, Sahu J, Brady M, Riobo NA, Mahoney MG - Oncotarget (2015)

Bottom Line: Aberrant activation of Hedgehog (Hh) signaling is causative of BCCs and has been associated with a fraction of SCCs.Ectopic expression of Dsg2 on Ptc1(+/lacZ) background enhanced epidermal proliferation and interfollicular activation of the Hh pathway.In summary, our results demonstrate that Dsg2 modulates Hh signaling, and this synergy may accelerate skin tumor development by different mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA, USA.

ABSTRACT
Aberrant activation of Hedgehog (Hh) signaling is causative of BCCs and has been associated with a fraction of SCCs. Desmoglein 2 (Dsg2) is an adhesion protein that is upregulated in many cancers and overexpression of Dsg2 in the epidermis renders mice more susceptible to squamous-derived neoplasia. Here we examined a potential crosstalk between Dsg2 and Hh signaling in skin tumorigenesis. Our findings show that Dsg2 modulates Gli1 expression, in vitro and in vivo. Ectopic expression of Dsg2 on Ptc1(+/lacZ) background enhanced epidermal proliferation and interfollicular activation of the Hh pathway. Furthermore, in response to DMBA/TPA, the Dsg2/Ptc1+/lacZ mice developed squamous lessons earlier than the WT, Ptc1(+/lacZ), and Inv-Dsg2 littermates. Additionally, DMBA/TPA induced BCC formation in all mice harboring the Ptc1(+/lacZ) gene and the presence of Dsg2 in Dsg2/Ptc1(+/lacZ) mice doubled the BCC tumor burden. Reporter analysis revealed activation of the Hh pathway in the BCC tumors. However, in the SCCs we observed Hh activity only in the underlying dermis of the tumors. Furthermore, Dsg2/Ptc1(+/lacZ) mice demonstrated enhanced MEK/Erk1/2 activation within the tumors and expression of Shh in the dermis. In summary, our results demonstrate that Dsg2 modulates Hh signaling, and this synergy may accelerate skin tumor development by different mechanisms.

No MeSH data available.


Related in: MedlinePlus

Dsg2 enhances Gli1 expressionA–B. qPCR analysis of 6-week old backskin from Inv-Dsg2 (n = 8) and WT (n = 6) mice. Samples normalized to internal control (GAPDH); in addition to control for follicles in the anagen stage of development, samples were normalized to Sox9. C. Western analysis of A431-shDsg2 and A431-shDsg2 lysates (n = 3), for Dsg2 and Gli1. Actin serves as a loading control. Densitometry measurements were completed using image J. D. qPCR of HaCaT-shDsg2 and HaCaT-shGFP control cells (n = 3). Samples were normalized to GAPDH. All data are shown as the mean ± SEM; *p < 0.05, **p < 0.01, ***p < 0.001; t-test.
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Figure 1: Dsg2 enhances Gli1 expressionA–B. qPCR analysis of 6-week old backskin from Inv-Dsg2 (n = 8) and WT (n = 6) mice. Samples normalized to internal control (GAPDH); in addition to control for follicles in the anagen stage of development, samples were normalized to Sox9. C. Western analysis of A431-shDsg2 and A431-shDsg2 lysates (n = 3), for Dsg2 and Gli1. Actin serves as a loading control. Densitometry measurements were completed using image J. D. qPCR of HaCaT-shDsg2 and HaCaT-shGFP control cells (n = 3). Samples were normalized to GAPDH. All data are shown as the mean ± SEM; *p < 0.05, **p < 0.01, ***p < 0.001; t-test.

Mentions: To determine the effect of Dsg2 on Hh signaling in vivo, we quantified expression of gli1 and ptc1 mRNA in the skin of 6 week-old Inv-Dsg2 transgenic mice and wild type (WT) littermates. Analysis by qPCR confirmed enhanced Dsg2 expression and revealed an ~7-fold increase in gli1 and ptc1 mRNA in the skin of Inv-Dsg2 mice (Figure 1A). As activation of the Hh pathway is a hallmark of hair follicles in anagen, we also normalized the gli1 and ptc1 Ct values to the anagen hair follicle marker sox9 to confirm that the increase in Hh target genes was not secondary to an increased number of anagen follicles. Strikingly, normalization of gli1 and ptc1 to sox9 resulted in an even higher upregulation of gli1 and ptc1 (~20 and 10-fold respectively) (Figure 1A); suggesting that the observed increase in gli1 and ptc1 could not be accounted for by an increase in hair follicle number or an alteration in the hair follicle cycle. Remarkably, expression of Shh at the transcript level was highly upregulated in the skin of Inv-Dsg2 mice (800-fold vs. WT), suggesting that it may account for increased Gli target gene expression in vivo (Figure 1B). Thus, overexpressing Dsg2 in the epidermis increases canonical Hh pathway activity in vivo.


Crosstalk between Desmoglein 2 and Patched 1 accelerates chemical-induced skin tumorigenesis.

Brennan-Crispi DM, Hossain C, Sahu J, Brady M, Riobo NA, Mahoney MG - Oncotarget (2015)

Dsg2 enhances Gli1 expressionA–B. qPCR analysis of 6-week old backskin from Inv-Dsg2 (n = 8) and WT (n = 6) mice. Samples normalized to internal control (GAPDH); in addition to control for follicles in the anagen stage of development, samples were normalized to Sox9. C. Western analysis of A431-shDsg2 and A431-shDsg2 lysates (n = 3), for Dsg2 and Gli1. Actin serves as a loading control. Densitometry measurements were completed using image J. D. qPCR of HaCaT-shDsg2 and HaCaT-shGFP control cells (n = 3). Samples were normalized to GAPDH. All data are shown as the mean ± SEM; *p < 0.05, **p < 0.01, ***p < 0.001; t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496169&req=5

Figure 1: Dsg2 enhances Gli1 expressionA–B. qPCR analysis of 6-week old backskin from Inv-Dsg2 (n = 8) and WT (n = 6) mice. Samples normalized to internal control (GAPDH); in addition to control for follicles in the anagen stage of development, samples were normalized to Sox9. C. Western analysis of A431-shDsg2 and A431-shDsg2 lysates (n = 3), for Dsg2 and Gli1. Actin serves as a loading control. Densitometry measurements were completed using image J. D. qPCR of HaCaT-shDsg2 and HaCaT-shGFP control cells (n = 3). Samples were normalized to GAPDH. All data are shown as the mean ± SEM; *p < 0.05, **p < 0.01, ***p < 0.001; t-test.
Mentions: To determine the effect of Dsg2 on Hh signaling in vivo, we quantified expression of gli1 and ptc1 mRNA in the skin of 6 week-old Inv-Dsg2 transgenic mice and wild type (WT) littermates. Analysis by qPCR confirmed enhanced Dsg2 expression and revealed an ~7-fold increase in gli1 and ptc1 mRNA in the skin of Inv-Dsg2 mice (Figure 1A). As activation of the Hh pathway is a hallmark of hair follicles in anagen, we also normalized the gli1 and ptc1 Ct values to the anagen hair follicle marker sox9 to confirm that the increase in Hh target genes was not secondary to an increased number of anagen follicles. Strikingly, normalization of gli1 and ptc1 to sox9 resulted in an even higher upregulation of gli1 and ptc1 (~20 and 10-fold respectively) (Figure 1A); suggesting that the observed increase in gli1 and ptc1 could not be accounted for by an increase in hair follicle number or an alteration in the hair follicle cycle. Remarkably, expression of Shh at the transcript level was highly upregulated in the skin of Inv-Dsg2 mice (800-fold vs. WT), suggesting that it may account for increased Gli target gene expression in vivo (Figure 1B). Thus, overexpressing Dsg2 in the epidermis increases canonical Hh pathway activity in vivo.

Bottom Line: Aberrant activation of Hedgehog (Hh) signaling is causative of BCCs and has been associated with a fraction of SCCs.Ectopic expression of Dsg2 on Ptc1(+/lacZ) background enhanced epidermal proliferation and interfollicular activation of the Hh pathway.In summary, our results demonstrate that Dsg2 modulates Hh signaling, and this synergy may accelerate skin tumor development by different mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA, USA.

ABSTRACT
Aberrant activation of Hedgehog (Hh) signaling is causative of BCCs and has been associated with a fraction of SCCs. Desmoglein 2 (Dsg2) is an adhesion protein that is upregulated in many cancers and overexpression of Dsg2 in the epidermis renders mice more susceptible to squamous-derived neoplasia. Here we examined a potential crosstalk between Dsg2 and Hh signaling in skin tumorigenesis. Our findings show that Dsg2 modulates Gli1 expression, in vitro and in vivo. Ectopic expression of Dsg2 on Ptc1(+/lacZ) background enhanced epidermal proliferation and interfollicular activation of the Hh pathway. Furthermore, in response to DMBA/TPA, the Dsg2/Ptc1+/lacZ mice developed squamous lessons earlier than the WT, Ptc1(+/lacZ), and Inv-Dsg2 littermates. Additionally, DMBA/TPA induced BCC formation in all mice harboring the Ptc1(+/lacZ) gene and the presence of Dsg2 in Dsg2/Ptc1(+/lacZ) mice doubled the BCC tumor burden. Reporter analysis revealed activation of the Hh pathway in the BCC tumors. However, in the SCCs we observed Hh activity only in the underlying dermis of the tumors. Furthermore, Dsg2/Ptc1(+/lacZ) mice demonstrated enhanced MEK/Erk1/2 activation within the tumors and expression of Shh in the dermis. In summary, our results demonstrate that Dsg2 modulates Hh signaling, and this synergy may accelerate skin tumor development by different mechanisms.

No MeSH data available.


Related in: MedlinePlus