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XPC inhibits NSCLC cell proliferation and migration by enhancing E-Cadherin expression.

Cui T, Srivastava AK, Han C, Yang L, Zhao R, Zou N, Qu M, Duan W, Zhang X, Wang QE - Oncotarget (2015)

Bottom Line: Deletion of XPC is associated with early stages of human lung carcinogenesis, and reduced XPC mRNA levels predict poor patient outcome for non-small cell lung cancer (NSCLC).Restoration of E-Cadherin in these cells suppressed XPC knockdown-induced cell growth both in vitro and in vivo.Mechanistic studies showed that the loss of XPC repressed E-Cadherin expression by activating the ERK pathway and upregulating Snail expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.

ABSTRACT
Xeroderma pigmentosum complementation group C (XPC) protein is an important DNA damage recognition factor in nucleotide excision repair. Deletion of XPC is associated with early stages of human lung carcinogenesis, and reduced XPC mRNA levels predict poor patient outcome for non-small cell lung cancer (NSCLC). However, the mechanisms linking loss of XPC expression and poor prognosis in lung cancer are still unclear. Here, we report evidence that XPC silencing drives proliferation and migration of NSCLC cells by down-regulating E-Cadherin. XPC knockdown enhanced proliferation and migration while decreasing E-Cadherin expression in NSCLC cells with an epithelial phenotype. Restoration of E-Cadherin in these cells suppressed XPC knockdown-induced cell growth both in vitro and in vivo. Mechanistic studies showed that the loss of XPC repressed E-Cadherin expression by activating the ERK pathway and upregulating Snail expression. Our findings indicate that XPC silencing-induced reduction of E-Cadherin expression contributes, at least in part, to the poor outcome of NSCLC patients with low XPC expression.

No MeSH data available.


Related in: MedlinePlus

XPC regulates cell proliferation of NSCLC cells through the ERK/Snail/E-Cadherin pathway(A-C) Expression of phospho-ERK1/2 was detected in A549 and H460 cells either transiently transfected with siXPC or stably transfected with shXPC. The intensity of p-ERK1/2 bands was quantified using ImageJ and normalized to ERK2 and then to siCtrl/shCtrl-transfected cells. (D-F) Two clones of A549 cells with stable XPC knockdown were treated with the ERK inhibitor PD98059 for 24 h. Expression of p-ERK1/2, Snail, and E-Cadherin was detected using immunoblotting. The intensity of each band was quantified using ImageJ and normalized to either ERK2, or Lamin B, and then to non-treated cells (D). Cell growth was determined using methylene blue staining. n = 5, bar: SD, *, P < 0.05, **, P < 0.01 (E,F).
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Figure 5: XPC regulates cell proliferation of NSCLC cells through the ERK/Snail/E-Cadherin pathway(A-C) Expression of phospho-ERK1/2 was detected in A549 and H460 cells either transiently transfected with siXPC or stably transfected with shXPC. The intensity of p-ERK1/2 bands was quantified using ImageJ and normalized to ERK2 and then to siCtrl/shCtrl-transfected cells. (D-F) Two clones of A549 cells with stable XPC knockdown were treated with the ERK inhibitor PD98059 for 24 h. Expression of p-ERK1/2, Snail, and E-Cadherin was detected using immunoblotting. The intensity of each band was quantified using ImageJ and normalized to either ERK2, or Lamin B, and then to non-treated cells (D). Cell growth was determined using methylene blue staining. n = 5, bar: SD, *, P < 0.05, **, P < 0.01 (E,F).

Mentions: It has been reported that the expression of Snail can be downregulated through the inhibition of the PI3K/AKT or MAPK/ERK pathway [29, 30]. To investigate whether these pathways are affected by XPC modulation, we determined the phosphorylation of AKT and ERK1/2 in A549 and H460 cells after being transiently transfected with XPC siRNA, as well as A549 cells with stable XPC knockdown. We did not see any effect of XPC downregulation on AKT phosphorylation (Supplementary Figure 8). However, downregulation of XPC resulted in an increased phosphorylation of ERK1/2 in both A549 and H460 cell lines (Figures 5A-C), indicating that XPC is able to inhibit the ERK pathway in NSCLC cells. In addition, XPC knockdown-enhanced Snail expression could be blocked by the inhibition of the ERK pathway, accompanied by an increased expression of E-Cadherin (Figure 5D). Furthermore, the ERK pathway inhibition by the ERK1/2 inhibitor could also impede XPC deficiency-induced cell proliferation (Figures 5E-F). These data suggest that XPC insufficiency may promote NSCLC cell growth through the activation of the ERK pathway. Activated ERK pathway enhances Snail expression, which further suppresses E-Cadherin expression, leading to an accelerated cell proliferation.


XPC inhibits NSCLC cell proliferation and migration by enhancing E-Cadherin expression.

Cui T, Srivastava AK, Han C, Yang L, Zhao R, Zou N, Qu M, Duan W, Zhang X, Wang QE - Oncotarget (2015)

XPC regulates cell proliferation of NSCLC cells through the ERK/Snail/E-Cadherin pathway(A-C) Expression of phospho-ERK1/2 was detected in A549 and H460 cells either transiently transfected with siXPC or stably transfected with shXPC. The intensity of p-ERK1/2 bands was quantified using ImageJ and normalized to ERK2 and then to siCtrl/shCtrl-transfected cells. (D-F) Two clones of A549 cells with stable XPC knockdown were treated with the ERK inhibitor PD98059 for 24 h. Expression of p-ERK1/2, Snail, and E-Cadherin was detected using immunoblotting. The intensity of each band was quantified using ImageJ and normalized to either ERK2, or Lamin B, and then to non-treated cells (D). Cell growth was determined using methylene blue staining. n = 5, bar: SD, *, P < 0.05, **, P < 0.01 (E,F).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 5: XPC regulates cell proliferation of NSCLC cells through the ERK/Snail/E-Cadherin pathway(A-C) Expression of phospho-ERK1/2 was detected in A549 and H460 cells either transiently transfected with siXPC or stably transfected with shXPC. The intensity of p-ERK1/2 bands was quantified using ImageJ and normalized to ERK2 and then to siCtrl/shCtrl-transfected cells. (D-F) Two clones of A549 cells with stable XPC knockdown were treated with the ERK inhibitor PD98059 for 24 h. Expression of p-ERK1/2, Snail, and E-Cadherin was detected using immunoblotting. The intensity of each band was quantified using ImageJ and normalized to either ERK2, or Lamin B, and then to non-treated cells (D). Cell growth was determined using methylene blue staining. n = 5, bar: SD, *, P < 0.05, **, P < 0.01 (E,F).
Mentions: It has been reported that the expression of Snail can be downregulated through the inhibition of the PI3K/AKT or MAPK/ERK pathway [29, 30]. To investigate whether these pathways are affected by XPC modulation, we determined the phosphorylation of AKT and ERK1/2 in A549 and H460 cells after being transiently transfected with XPC siRNA, as well as A549 cells with stable XPC knockdown. We did not see any effect of XPC downregulation on AKT phosphorylation (Supplementary Figure 8). However, downregulation of XPC resulted in an increased phosphorylation of ERK1/2 in both A549 and H460 cell lines (Figures 5A-C), indicating that XPC is able to inhibit the ERK pathway in NSCLC cells. In addition, XPC knockdown-enhanced Snail expression could be blocked by the inhibition of the ERK pathway, accompanied by an increased expression of E-Cadherin (Figure 5D). Furthermore, the ERK pathway inhibition by the ERK1/2 inhibitor could also impede XPC deficiency-induced cell proliferation (Figures 5E-F). These data suggest that XPC insufficiency may promote NSCLC cell growth through the activation of the ERK pathway. Activated ERK pathway enhances Snail expression, which further suppresses E-Cadherin expression, leading to an accelerated cell proliferation.

Bottom Line: Deletion of XPC is associated with early stages of human lung carcinogenesis, and reduced XPC mRNA levels predict poor patient outcome for non-small cell lung cancer (NSCLC).Restoration of E-Cadherin in these cells suppressed XPC knockdown-induced cell growth both in vitro and in vivo.Mechanistic studies showed that the loss of XPC repressed E-Cadherin expression by activating the ERK pathway and upregulating Snail expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.

ABSTRACT
Xeroderma pigmentosum complementation group C (XPC) protein is an important DNA damage recognition factor in nucleotide excision repair. Deletion of XPC is associated with early stages of human lung carcinogenesis, and reduced XPC mRNA levels predict poor patient outcome for non-small cell lung cancer (NSCLC). However, the mechanisms linking loss of XPC expression and poor prognosis in lung cancer are still unclear. Here, we report evidence that XPC silencing drives proliferation and migration of NSCLC cells by down-regulating E-Cadherin. XPC knockdown enhanced proliferation and migration while decreasing E-Cadherin expression in NSCLC cells with an epithelial phenotype. Restoration of E-Cadherin in these cells suppressed XPC knockdown-induced cell growth both in vitro and in vivo. Mechanistic studies showed that the loss of XPC repressed E-Cadherin expression by activating the ERK pathway and upregulating Snail expression. Our findings indicate that XPC silencing-induced reduction of E-Cadherin expression contributes, at least in part, to the poor outcome of NSCLC patients with low XPC expression.

No MeSH data available.


Related in: MedlinePlus