Project description:Although ERBB2 amplification and overexpression is correlated with poor outcome in breast cancer, the molecular mechanisms underlying the aggressive nature of these tumors has not been fully elucidated. To investigate this further, we have used a transgenic mouse model of ErbB2-driven tumor progression (ErbB2KI model) that recapitulates clinically relevant events, including selective amplification of the core erbB2 amplicon. By comparing the transcriptional profiles of ErbB2KI mammary tumors and human ERBB2-positive breast cancers, we demonstrate that ErbB2KI tumors possess molecular features of the basal subtype of ERBB2-positive human breast cancer, including activation of canonical β-catenin signaling. Inhibition of β-catenin-dependent signaling in ErbB2KI-derived tumor cells using RNA interference impaired tumor initiation and metastasis. Furthermore, treatment of ErbB2KI or human ERBB2-overexpressing tumor cells with a selective β-catenin/CBP inhibitor significantly decreased proliferation and ErbB2 expression. Collectively, our data indicate that ERBB2-mediated breast cancer progression requires β-catenin signaling and can be therapeutically targeted by selective β-catenin/CBP inhibitors. Common reference design. 9 samples (including 2 normal tissue, 2 NIC tumors, and 5 KI tumor tissue samples) replicated twice as dye swaps, generating a total of 18 arrays.
Project description:Although ERBB2 amplification and overexpression is correlated with poor outcome in breast cancer, the molecular mechanisms underlying the aggressive nature of these tumors has not been fully elucidated. To investigate this further, we have used a transgenic mouse model of ErbB2-driven tumor progression (ErbB2KI model) that recapitulates clinically relevant events, including selective amplification of the core erbB2 amplicon. By comparing the transcriptional profiles of ErbB2KI mammary tumors and human ERBB2-positive breast cancers, we demonstrate that ErbB2KI tumors possess molecular features of the basal subtype of ERBB2-positive human breast cancer, including activation of canonical β-catenin signaling. Inhibition of β-catenin-dependent signaling in ErbB2KI-derived tumor cells using RNA interference impaired tumor initiation and metastasis. Furthermore, treatment of ErbB2KI or human ERBB2-overexpressing tumor cells with a selective β-catenin/CBP inhibitor significantly decreased proliferation and ErbB2 expression. Collectively, our data indicate that ERBB2-mediated breast cancer progression requires β-catenin signaling and can be therapeutically targeted by selective β-catenin/CBP inhibitors.
Project description:Many components of Wnt/β-catenin signaling pathway also play critical roles in mammary tumor development. To study the role of Apc in mammary tumorigensis, we introduced conditional Apc mutations specifically into two different mammary epithelial populations using K14-Cre (progenitor) and WAP-cre (lactaing luminal) transgenic mice. Only the K14-cre mediated Apc heterozygosity developed mammary adenocarcinomas demonstrating histological and molecular heterogeneity, suggesting the progenitor cell origin of these tumors. These tumors harbored truncation mutation in a very defined region in the remaining wild-type allele of Apc that would retain some down-regulating activity of β-catenin signaling. Our results suggest that not only the epithelial origin but also a certain Apc mutations are selected to achieve a specific level of β-catenin signaling optimal for mammary tumor development.
Project description:Summary: We studied how the binding of beta-catenin to the transcriptional coactivators B-cell CLL/lymphoma 9 (Bcl9) and Bcl9-Like (Bcl9L) affected mammary gland carcinogenesis in the MMTV-PyMT transgenic mouse model of metastatic breast cancer. Conditional knockout of both Bcl9 and Bcl9L resulted into tumor cell death. In contrast, disrupting the interaction of Bcl9/Bcl9L with beta-catenin, either by deletion of their HD2 domains or by a point mutation in the N-terminal domain of beta-catenin (D164A), diminished primary tumor growth and tumor cell proliferation and reduced tumor cell invasion and lung metastasis. In comparison, the effect of disrupting the HD1 domain-mediated binding of Bcl9/Bcl9L to Pygopus was more moderate. Interfering with the beta-catenin - Bcl9/Bcl9L - Pygo chain of adaptors only partially impaired the transcriptional response of mammary tumor cells to Wnt3a and TGF-beta treatment. The results indicate that Bcl9/Bcl9L critically enforce canonical Wnt signaling in its contribution to breast cancer growth and malignant progression.
Project description:The orphan nuclear receptor NR2E3 (Nuclear receptor subfamily 2 group E, Member 3) is an epigenetic player essential for p53 activation during liver injuries through its modulation of chromatin accessibility. Nonetheless, a precise tumor suppressive and epigenetic role of NR2E3 in hepatocellular carcinoma (HCC) remains unclear. HCC patients expressing low NR2E3 exhibit unfavorable clinical outcomes, aligning with heightened activation of the WNT/β-catenin signaling pathway. The murine HCC models utilizing NR2E3 knockout mice consistently exhibits accelerated liver tumor formation and progression accompanied by enhanced activation of WNT/β-catenin signaling pathway and inactivation of p53 signaling pathway. At cellular level, the loss of NR2E3 increases the acquisition of aggressive cancer cell phenotype and tumorigenicity and upregulates key genes in the WNT/β-catenin pathway with enhanced chromatin accessibility. This event is mediated through increased formation of active transcription complex involving Sp1, β-catenin, and p300, a histone acetyltransferase, on the promoters of target genes. These findings demonstrate that the loss of NR2E3 promotes WNT/β-catenin signaling activation at cellular, organismal, and clinical levels. In summary, NR2E3 is a novel tumor suppressor that maintains epigenetic homeostasis, thereby preventing activation of WNT/β-catenin signaling that promotes HCC formation and progression.
Project description:Previously we have demonstrated that inactivation of retinoic acid receptor beta (Rarb) in the mouse results in a protective effect against ErbB2-induced mammary gland tumorigenesis although Rarb has been reported as a tumor suppressor before. In the current study, we further confirmed that ablation of Rarb has a very similar impact on Wnt1-induced mammary gland tumorigenesis as those on ErbB2-induced mammary gland tumorigenesis. Nevertheless, the mechanisms by which Rarb confers its effects on tumor progression is quite different although both involving in tumor microenvironment (TME) remodeling. In the Wnt1 tumors, ectopic wnt1 produced by malignant luminal cells activates nearby stromal cells by a paracrine manner. In return, the stromal cells secreted IGF1 to regulate the growth of tumor cells. There is a need of Rarb expression in this interaction. Deletion of Rarb inhibits both wnt1/β-catenin signaling and IGF1/Akt axis in the myoepithelial tumor cells which results in the suppression of epithelial-mesenchymal transition (EMT) in these tumors. Since wnt1 tumors resemble basal-like breast cancer with a poor clinical prognosis in which EMT is one of the most important way for tumor cells to survive against standard treatment and to go to metastasis, we propose that (1) the stromal gene expression signature of Rarb ablation in wnt1 tumors could have some clinical value in predicting the breast cancer outcome; and (2) Rarb antagonist might be a potential therapeutic strategy in EMT-driven aggressive cancers such as basal-like breast cancer. Laser capture microdissection (LCM) was performed to separate the mammary tumor samples into epithelial cell compartment and stromal cell compartment. Transcriptional profiling of the two compartments were investigated by microarray analysis.
Project description:Many components of Wnt/β-catenin signaling pathway also play critical roles in mammary tumor development. To study the role of Apc in mammary tumorigensis, we introduced conditional Apc mutations specifically into two different mammary epithelial populations using K14-Cre (progenitor) and WAP-cre (lactaing luminal) transgenic mice. Only the K14-cre mediated Apc heterozygosity developed mammary adenocarcinomas demonstrating histological and molecular heterogeneity, suggesting the progenitor cell origin of these tumors. These tumors harbored truncation mutation in a very defined region in the remaining wild-type allele of Apc that would retain some down-regulating activity of β-catenin signaling. Our results suggest that not only the epithelial origin but also a certain Apc mutations are selected to achieve a specific level of β-catenin signaling optimal for mammary tumor development. Experiment Overall Design: We have compared 3 mammary tumors from K14-cre; ApcCKO/+ mice with 3 control mammary glands.
Project description:Wnt/β-catenin signaling pathway has become a key signaling pathway regulating mammary organogenesis and oncogenesis. However, the therapeutic methods by targeting Wnt pathway against breast cancer has been limited. To address this challenge, we investigated the function of cyclin-dependent kinase 14 (CDK14), a member of Wnt signaling pathway, in mammary development and breast cancer progression. We showed that CDK14 was expressed in the mammary basal layer and elevated in triple negative breast cancer (TNBC). CDK14 knockdown reduces colony formation ability and regeneration capacity of mammary basal cells, and significantly inhibits murine MMTV-Wnt-1 basal-like mammary tumor progression. Excitingly, knockdown of CDK14 or pharmacological inhibition of CDK14 by FMF-04-159-2 significantly inhibited the progression and metastasis of human TNBC. Mechanistically, CDK14 inhibition inhibits mammary regeneration and TNBC progression by attenuating Wnt/β-catenin signaling. Together, we demonstrated that CDK14 regulates mammary regeneration and breast tumorigenesis, and is a promising therapeutic target for TNBC.
Project description:Wnt/β-catenin signaling pathway has become a key signaling pathway regulating mammary organogenesis and oncogenesis. However, the therapeutic methods by targeting Wnt pathway against breast cancer has been limited. To address this challenge, we investigated the function of cyclin-dependent kinase 14 (CDK14), a member of Wnt signaling pathway, in mammary development and breast cancer progression. We showed that CDK14 was expressed in the mammary basal layer and elevated in triple negative breast cancer (TNBC). CDK14 knockdown reduces colony formation ability and regeneration capacity of mammary basal cells, and significantly inhibits murine MMTV-Wnt-1 basal-like mammary tumor progression. Excitingly, knockdown of CDK14 or pharmacological inhibition of CDK14 by FMF-04-159-2 significantly inhibited the progression and metastasis of human TNBC. Mechanistically, CDK14 inhibition inhibits mammary regeneration and TNBC progression by attenuating Wnt/β-catenin signaling. Together, we demonstrated that CDK14 regulates mammary regeneration and breast tumorigenesis, and is a promising therapeutic target for TNBC.
Project description:Wnt/β-catenin signaling pathway has become a key signaling pathway regulating mammary organogenesis and oncogenesis. However, the therapeutic methods by targeting Wnt pathway against breast cancer has been limited. To address this challenge, we investigated the function of cyclin-dependent kinase 14 (CDK14), a member of Wnt signaling pathway, in mammary development and breast cancer progression. We showed that CDK14 was expressed in the mammary basal layer and elevated in triple negative breast cancer (TNBC). CDK14 knockdown reduces colony formation ability and regeneration capacity of mammary basal cells, and significantly inhibits murine MMTV-Wnt-1 basal-like mammary tumor progression. Excitingly, knockdown of CDK14 or pharmacological inhibition of CDK14 by FMF-04-159-2 significantly inhibited the progression and metastasis of human TNBC. Mechanistically, CDK14 inhibition inhibits mammary regeneration and TNBC progression by attenuating Wnt/β-catenin signaling. Together, we demonstrated that CDK14 regulates mammary regeneration and breast tumorigenesis, and is a promising therapeutic target for TNBC.