Limits...
FBXW7 modulates cellular stress response and metastatic potential through ​HSF1 post-translational modification.

Kourtis N, Moubarak RS, Aranda-Orgilles B, Lui K, Aydin IT, Trimarchi T, Darvishian F, Salvaggio C, Zhong J, Bhatt K, Chen EI, Celebi JT, Lazaris C, Tsirigos A, Osman I, Hernando E, Aifantis I - Nat. Cell Biol. (2015)

Bottom Line: ​Heat-shock factor 1 (​HSF1) orchestrates the heat-shock response in eukaryotes.Although this pathway has evolved to help cells adapt in the presence of challenging conditions, it is co-opted in cancer to support malignancy.Here we show that the ubiquitin ligase ​FBXW7α interacts with ​HSF1 through a conserved motif phosphorylated by ​GSK3β and ​ERK1. ​FBXW7α ubiquitylates ​HSF1 and loss of ​FBXW7α results in impaired degradation of nuclear ​HSF1 and defective heat-shock response attenuation. ​FBXW7α is either mutated or transcriptionally downregulated in melanoma and ​HSF1 nuclear stabilization correlates with increased metastatic potential and disease progression. ​FBXW7α deficiency and subsequent ​HSF1 accumulation activates an invasion-supportive transcriptional program and enhances the metastatic potential of human melanoma cells.

View Article: PubMed Central - PubMed

ABSTRACT
​Heat-shock factor 1 (​HSF1) orchestrates the heat-shock response in eukaryotes. Although this pathway has evolved to help cells adapt in the presence of challenging conditions, it is co-opted in cancer to support malignancy. However, the mechanisms that regulate ​HSF1 and thus cellular stress response are poorly understood. Here we show that the ubiquitin ligase ​FBXW7α interacts with ​HSF1 through a conserved motif phosphorylated by ​GSK3β and ​ERK1. ​FBXW7α ubiquitylates ​HSF1 and loss of ​FBXW7α results in impaired degradation of nuclear ​HSF1 and defective heat-shock response attenuation. ​FBXW7α is either mutated or transcriptionally downregulated in melanoma and ​HSF1 nuclear stabilization correlates with increased metastatic potential and disease progression. ​FBXW7α deficiency and subsequent ​HSF1 accumulation activates an invasion-supportive transcriptional program and enhances the metastatic potential of human melanoma cells. These findings identify a post-translational mechanism of regulation of the ​HSF1 transcriptional program both in the presence of exogenous stress and in cancer.

Show MeSH

Related in: MedlinePlus

HSF1 protein levels and HSF1 targets expression are associated with metastasis and disease progression in melanoma(a) IHC staining with anti-HSF1 antibody of the indicated tissue types (dysplastic nevi n=48, primary n=39 and metastatic n=45; P<0.001 for metastatic versus primary or nevi; unpaired t-test; scale bar, 200 μm). (b) Box plots showing expression of HSF1 targets (HSPD1, HSPE1, HSPH1, CKS2), FBXW7 and HSF1, derived from microarray analysis of normal skin (n=4), primary (n=42) and metastatic melanoma (n=40) samples58. Whiskers represent the upper and the lower limits of the range. Boxes represent the first and third quartile, and the line represents the median (unpaired t-test). (c) IHC staining with anti-FBXW7 and anti-HSF1 antibodies of the indicated tissue types (dysplastic nevi n=59, primary n=53 and metastatic n=53; P<0.001 for nevi FBXW7 versus HSF1, P<0.01 for primary FBXW7 versus HSF1, P<0.05 for metastatic FBXW7 versus HSF1; unpaired t-test; scale bar, 200 μm). (d) Kaplan-Meier survival curves of patients with tumors expressing high (2D, n = 76) or low levels of nuclear HSF1 (including 0, 1F and 1D, n = 101; P= 0.01; Log rank test). Staining was scored according to the intensity (0-2) and distribution (Focal <50%, Diffuse ≥50%). (e) FBXW7 expression inversely correlates with HSF1 mRNA signature. FBXW7α (NM_033632) expression levels were measured by RNA-Seq in 325 Skin Cutaneous Melanoma (SKCM) samples from TCGA. HSF1 mRNA signature was defined as 1,864 mRNA expressions that were significantly correlated with HSF1 expression (NM_005526) with Spearman Correlation Coefficient > 0.3 and FDR < 5% in TCGA samples. Among them, 830 mRNAs with positive correlations were defined as the positive signature, while 1,034 mRNAs with negative correlations were defined as the negative signature. The first Principal Component (PC1) of the HSF1 positive signature was negatively correlated with FBXW7α expression (Spearman Correlation Coefficient = -0.4; P< 0.001); while the PC1 of the HSF1 negative signature was positively correlated with FBXW7α expression (Spearman Correlation Coefficient = 0.42; P< 0.001).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4401662&req=5

Figure 4: HSF1 protein levels and HSF1 targets expression are associated with metastasis and disease progression in melanoma(a) IHC staining with anti-HSF1 antibody of the indicated tissue types (dysplastic nevi n=48, primary n=39 and metastatic n=45; P<0.001 for metastatic versus primary or nevi; unpaired t-test; scale bar, 200 μm). (b) Box plots showing expression of HSF1 targets (HSPD1, HSPE1, HSPH1, CKS2), FBXW7 and HSF1, derived from microarray analysis of normal skin (n=4), primary (n=42) and metastatic melanoma (n=40) samples58. Whiskers represent the upper and the lower limits of the range. Boxes represent the first and third quartile, and the line represents the median (unpaired t-test). (c) IHC staining with anti-FBXW7 and anti-HSF1 antibodies of the indicated tissue types (dysplastic nevi n=59, primary n=53 and metastatic n=53; P<0.001 for nevi FBXW7 versus HSF1, P<0.01 for primary FBXW7 versus HSF1, P<0.05 for metastatic FBXW7 versus HSF1; unpaired t-test; scale bar, 200 μm). (d) Kaplan-Meier survival curves of patients with tumors expressing high (2D, n = 76) or low levels of nuclear HSF1 (including 0, 1F and 1D, n = 101; P= 0.01; Log rank test). Staining was scored according to the intensity (0-2) and distribution (Focal <50%, Diffuse ≥50%). (e) FBXW7 expression inversely correlates with HSF1 mRNA signature. FBXW7α (NM_033632) expression levels were measured by RNA-Seq in 325 Skin Cutaneous Melanoma (SKCM) samples from TCGA. HSF1 mRNA signature was defined as 1,864 mRNA expressions that were significantly correlated with HSF1 expression (NM_005526) with Spearman Correlation Coefficient > 0.3 and FDR < 5% in TCGA samples. Among them, 830 mRNAs with positive correlations were defined as the positive signature, while 1,034 mRNAs with negative correlations were defined as the negative signature. The first Principal Component (PC1) of the HSF1 positive signature was negatively correlated with FBXW7α expression (Spearman Correlation Coefficient = -0.4; P< 0.001); while the PC1 of the HSF1 negative signature was positively correlated with FBXW7α expression (Spearman Correlation Coefficient = 0.42; P< 0.001).

Mentions: To further investigate the role of FBXW7-HSF1 interplay in human cancer progression and metastasis, we focused on melanoma, a solid tumor in which FBXW7 is frequently mutated and inactivated23, 30, 41. We tested HSF1 protein expression using immunohistochemistry in human specimens. We found that HSF1 protein levels were significantly increased as melanoma progressed to metastatic disease (P<0.001 for metastatic versus primary or nevi) (Fig. 4a). To assess the functional significance of HSF1 accumulation in melanoma, we asked whether HSF1 gene targets were upregulated during disease progression. Previously characterized HSF1 targets, including HSPD1, HSPE1, HSPH1 and CKS2 were expressed in significantly higher levels in metastatic melanoma compared to primary melanoma and normal skin (Fig. 4b). In contrast, FBXW7 expression was significantly reduced in metastatic melanoma, while HSF1 mRNA expression did not change significantly (Fig. 4b), suggesting post-translational regulation. In agreement with this model, we found that FBXW7 protein expression shows opposite pattern to HSF1 expression during disease progression (Figure 4c). To further investigate the hypothesis that HSF1 activation is associated with poor disease outcome, we expanded the primary human melanoma specimens cohort. These tumors were scored for levels of HSF1 and survival outcomes were investigated. Melanoma patients whose primary tumor expressed high levels of nuclear HSF1 had significantly decreased recurrence-free survival relative to the patients with low HSF1 levels (P=0.01, median follow up 5 years; Fig. 4d). These studies connect the FBXW7:HSF1 interaction to melanoma metastasis and disease progression.


FBXW7 modulates cellular stress response and metastatic potential through ​HSF1 post-translational modification.

Kourtis N, Moubarak RS, Aranda-Orgilles B, Lui K, Aydin IT, Trimarchi T, Darvishian F, Salvaggio C, Zhong J, Bhatt K, Chen EI, Celebi JT, Lazaris C, Tsirigos A, Osman I, Hernando E, Aifantis I - Nat. Cell Biol. (2015)

HSF1 protein levels and HSF1 targets expression are associated with metastasis and disease progression in melanoma(a) IHC staining with anti-HSF1 antibody of the indicated tissue types (dysplastic nevi n=48, primary n=39 and metastatic n=45; P<0.001 for metastatic versus primary or nevi; unpaired t-test; scale bar, 200 μm). (b) Box plots showing expression of HSF1 targets (HSPD1, HSPE1, HSPH1, CKS2), FBXW7 and HSF1, derived from microarray analysis of normal skin (n=4), primary (n=42) and metastatic melanoma (n=40) samples58. Whiskers represent the upper and the lower limits of the range. Boxes represent the first and third quartile, and the line represents the median (unpaired t-test). (c) IHC staining with anti-FBXW7 and anti-HSF1 antibodies of the indicated tissue types (dysplastic nevi n=59, primary n=53 and metastatic n=53; P<0.001 for nevi FBXW7 versus HSF1, P<0.01 for primary FBXW7 versus HSF1, P<0.05 for metastatic FBXW7 versus HSF1; unpaired t-test; scale bar, 200 μm). (d) Kaplan-Meier survival curves of patients with tumors expressing high (2D, n = 76) or low levels of nuclear HSF1 (including 0, 1F and 1D, n = 101; P= 0.01; Log rank test). Staining was scored according to the intensity (0-2) and distribution (Focal <50%, Diffuse ≥50%). (e) FBXW7 expression inversely correlates with HSF1 mRNA signature. FBXW7α (NM_033632) expression levels were measured by RNA-Seq in 325 Skin Cutaneous Melanoma (SKCM) samples from TCGA. HSF1 mRNA signature was defined as 1,864 mRNA expressions that were significantly correlated with HSF1 expression (NM_005526) with Spearman Correlation Coefficient > 0.3 and FDR < 5% in TCGA samples. Among them, 830 mRNAs with positive correlations were defined as the positive signature, while 1,034 mRNAs with negative correlations were defined as the negative signature. The first Principal Component (PC1) of the HSF1 positive signature was negatively correlated with FBXW7α expression (Spearman Correlation Coefficient = -0.4; P< 0.001); while the PC1 of the HSF1 negative signature was positively correlated with FBXW7α expression (Spearman Correlation Coefficient = 0.42; P< 0.001).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401662&req=5

Figure 4: HSF1 protein levels and HSF1 targets expression are associated with metastasis and disease progression in melanoma(a) IHC staining with anti-HSF1 antibody of the indicated tissue types (dysplastic nevi n=48, primary n=39 and metastatic n=45; P<0.001 for metastatic versus primary or nevi; unpaired t-test; scale bar, 200 μm). (b) Box plots showing expression of HSF1 targets (HSPD1, HSPE1, HSPH1, CKS2), FBXW7 and HSF1, derived from microarray analysis of normal skin (n=4), primary (n=42) and metastatic melanoma (n=40) samples58. Whiskers represent the upper and the lower limits of the range. Boxes represent the first and third quartile, and the line represents the median (unpaired t-test). (c) IHC staining with anti-FBXW7 and anti-HSF1 antibodies of the indicated tissue types (dysplastic nevi n=59, primary n=53 and metastatic n=53; P<0.001 for nevi FBXW7 versus HSF1, P<0.01 for primary FBXW7 versus HSF1, P<0.05 for metastatic FBXW7 versus HSF1; unpaired t-test; scale bar, 200 μm). (d) Kaplan-Meier survival curves of patients with tumors expressing high (2D, n = 76) or low levels of nuclear HSF1 (including 0, 1F and 1D, n = 101; P= 0.01; Log rank test). Staining was scored according to the intensity (0-2) and distribution (Focal <50%, Diffuse ≥50%). (e) FBXW7 expression inversely correlates with HSF1 mRNA signature. FBXW7α (NM_033632) expression levels were measured by RNA-Seq in 325 Skin Cutaneous Melanoma (SKCM) samples from TCGA. HSF1 mRNA signature was defined as 1,864 mRNA expressions that were significantly correlated with HSF1 expression (NM_005526) with Spearman Correlation Coefficient > 0.3 and FDR < 5% in TCGA samples. Among them, 830 mRNAs with positive correlations were defined as the positive signature, while 1,034 mRNAs with negative correlations were defined as the negative signature. The first Principal Component (PC1) of the HSF1 positive signature was negatively correlated with FBXW7α expression (Spearman Correlation Coefficient = -0.4; P< 0.001); while the PC1 of the HSF1 negative signature was positively correlated with FBXW7α expression (Spearman Correlation Coefficient = 0.42; P< 0.001).
Mentions: To further investigate the role of FBXW7-HSF1 interplay in human cancer progression and metastasis, we focused on melanoma, a solid tumor in which FBXW7 is frequently mutated and inactivated23, 30, 41. We tested HSF1 protein expression using immunohistochemistry in human specimens. We found that HSF1 protein levels were significantly increased as melanoma progressed to metastatic disease (P<0.001 for metastatic versus primary or nevi) (Fig. 4a). To assess the functional significance of HSF1 accumulation in melanoma, we asked whether HSF1 gene targets were upregulated during disease progression. Previously characterized HSF1 targets, including HSPD1, HSPE1, HSPH1 and CKS2 were expressed in significantly higher levels in metastatic melanoma compared to primary melanoma and normal skin (Fig. 4b). In contrast, FBXW7 expression was significantly reduced in metastatic melanoma, while HSF1 mRNA expression did not change significantly (Fig. 4b), suggesting post-translational regulation. In agreement with this model, we found that FBXW7 protein expression shows opposite pattern to HSF1 expression during disease progression (Figure 4c). To further investigate the hypothesis that HSF1 activation is associated with poor disease outcome, we expanded the primary human melanoma specimens cohort. These tumors were scored for levels of HSF1 and survival outcomes were investigated. Melanoma patients whose primary tumor expressed high levels of nuclear HSF1 had significantly decreased recurrence-free survival relative to the patients with low HSF1 levels (P=0.01, median follow up 5 years; Fig. 4d). These studies connect the FBXW7:HSF1 interaction to melanoma metastasis and disease progression.

Bottom Line: ​Heat-shock factor 1 (​HSF1) orchestrates the heat-shock response in eukaryotes.Although this pathway has evolved to help cells adapt in the presence of challenging conditions, it is co-opted in cancer to support malignancy.Here we show that the ubiquitin ligase ​FBXW7α interacts with ​HSF1 through a conserved motif phosphorylated by ​GSK3β and ​ERK1. ​FBXW7α ubiquitylates ​HSF1 and loss of ​FBXW7α results in impaired degradation of nuclear ​HSF1 and defective heat-shock response attenuation. ​FBXW7α is either mutated or transcriptionally downregulated in melanoma and ​HSF1 nuclear stabilization correlates with increased metastatic potential and disease progression. ​FBXW7α deficiency and subsequent ​HSF1 accumulation activates an invasion-supportive transcriptional program and enhances the metastatic potential of human melanoma cells.

View Article: PubMed Central - PubMed

ABSTRACT
​Heat-shock factor 1 (​HSF1) orchestrates the heat-shock response in eukaryotes. Although this pathway has evolved to help cells adapt in the presence of challenging conditions, it is co-opted in cancer to support malignancy. However, the mechanisms that regulate ​HSF1 and thus cellular stress response are poorly understood. Here we show that the ubiquitin ligase ​FBXW7α interacts with ​HSF1 through a conserved motif phosphorylated by ​GSK3β and ​ERK1. ​FBXW7α ubiquitylates ​HSF1 and loss of ​FBXW7α results in impaired degradation of nuclear ​HSF1 and defective heat-shock response attenuation. ​FBXW7α is either mutated or transcriptionally downregulated in melanoma and ​HSF1 nuclear stabilization correlates with increased metastatic potential and disease progression. ​FBXW7α deficiency and subsequent ​HSF1 accumulation activates an invasion-supportive transcriptional program and enhances the metastatic potential of human melanoma cells. These findings identify a post-translational mechanism of regulation of the ​HSF1 transcriptional program both in the presence of exogenous stress and in cancer.

Show MeSH
Related in: MedlinePlus