pf-3084014 and Breast-Neoplasms

The γ-secretase complex is a key hydrolase for many type 1 transmembrane proteins. It is very important for activation of the Notch receptor and regulation of target-gene transcription. Abnormal activation and expression of the Notch pathway are closely related to the occurrence and development of many tumor types, including breast cancer and liver cancer. In this review, we elaborated on the basic situation of γ-secretase complex and the biological function and role of γ-secretase in APP and Notch signal pathway are described in detail. Subsequently, all currently known γ-secretase inhibitors and γ-secretase modulators are listed and their mechanism of action, value of IC

Topics: Amyloid Precursor Protein Secretases; Antineoplastic Agents; Breast Neoplasms; Carcinoma, Hepatocellular; Female; Humans; Liver Neoplasms; Oligopeptides; Protease Inhibitors; Receptors, Notch; Tetrahydronaphthalenes; Valine

Fork head domain-containing transcription factor family (FOX), is comprised of >20 members. Members of FOX family have been implicated in a wide range of physiological and/or diseased conditions. Many of FOX members have been shown to be involved in tumorigenesis and progression. The potential roles in carcinogenesis of FOXN4, a member as one of the vast FOX family, remains relatively unknown.. Here, we explored the potential involvement of FOXN4 in breast cancer.. First, observed that a higher FOXN4 was identified in the normal adjacent breast tissue as compared to that in the breast cancer samples; an increased FOXN4 level was associated with a better prognosis in patients with breast cancer. In addition, ectopically expression of FOXN4 led to the decreased cell proliferation, reduced colony formation and metastatic abilities (EMT, migration and invasion) in breast cancer cell lines. Furthermore, we showed the direct interaction between FOXN4 and TP53 and FOXN4 binding led to the increased activity of TP53. Silencing FOXN4 led to reduced TP53 and increased expression of Dll4, Notch and survivin, providing a link between FOXN4 and Notch signaling. Finally, we used patient-derived xenograft mouse model to demonstrate the tumor inhibitory effects of Notch-inhibitor, PF-3084014. We found that PF-3084014 treatment led to a significantly smaller tumor burden and higher survival ratio in patient-derived xenograft mice as compared to the vehicle. This tumor suppressive effect was accompanied by the increased expression of TP53, FOXN4 and decreased Dll4 and Notch.. Collectively, our data strongly suggested the tumor suppressive roles of FOXN4 in breast tumorigenesis via the activation of TP53 while suppressing Notch signaling. Future studies are warranted to explore the clinical application of PF-3084104 (Notch inhibitor) for the treatment of breast cancer patients.

Topics: Adaptor Proteins, Signal Transducing; Adult; Animals; Breast Neoplasms; Calcium-Binding Proteins; Carcinogenesis; Cell Line, Tumor; Cell Proliferation; Female; Forkhead Transcription Factors; Humans; Intercellular Signaling Peptides and Proteins; Mammary Neoplasms, Experimental; Mice; Neoplasm Metastasis; Prognosis; Receptors, Notch; Signal Transduction; Tetrahydronaphthalenes; Tumor Suppressor Protein p53; Tumor Suppressor Proteins; Valine

Resistance to anti-estrogen therapies is a major cause of disease relapse and mortality in estrogen receptor alpha (ERα)-positive breast cancers. Tamoxifen or estrogen withdrawal increases the dependence of breast cancer cells on Notch signalling. Here, we investigated the contribution of Nicastrin and Notch signalling in endocrine-resistant breast cancer cells.. We used two models of endocrine therapies resistant (ETR) breast cancer: tamoxifen-resistant (TamR) and long-term estrogen-deprived (LTED) MCF7 cells. We evaluated the migratory and invasive capacity of these cells by Transwell assays. Expression of epithelial to mesenchymal transition (EMT) regulators as well as Notch receptors and targets were evaluated by real-time PCR and western blot analysis. Moreover, we tested in vitro anti-Nicastrin monoclonal antibodies (mAbs) and gamma secretase inhibitors (GSIs) as potential EMT reversal therapeutic agents. Finally, we generated stable Nicastrin overexpessing MCF7 cells and evaluated their EMT features and response to tamoxifen.. We found that ETR cells acquired an epithelial to mesenchymal transition (EMT) phenotype and displayed increased levels of Nicastrin and Notch targets. Interestingly, we detected higher level of Notch4 but lower levels of Notch1 and Notch2 suggesting a switch to signalling through different Notch receptors after acquisition of resistance. Anti-Nicastrin monoclonal antibodies and the GSI PF03084014 were effective in blocking the Nicastrin/Notch4 axis and partially inhibiting the EMT process. As a result of this, cell migration and invasion were attenuated and the stem cell-like population was significantly reduced. Genetic silencing of Nicastrin and Notch4 led to equivalent effects. Finally, stable overexpression of Nicastrin was sufficient to make MCF7 unresponsive to tamoxifen by Notch4 activation.. ETR cells express high levels of Nicastrin and Notch4, whose activation ultimately drives invasive behaviour. Anti-Nicastrin mAbs and GSI PF03084014 attenuate expression of EMT molecules reducing cellular invasiveness. Nicastrin overexpression per se induces tamoxifen resistance linked to acquisition of EMT phenotype. Our finding suggest that targeting Nicastrin and/or Notch4 warrants further clinical evaluation as valid therapeutic strategies in endocrine-resistant breast cancer.

Topics: Amyloid Precursor Protein Secretases; Antibodies, Monoclonal; Antineoplastic Agents, Hormonal; Breast Neoplasms; CD24 Antigen; Cell Movement; Drug Resistance, Neoplasm; Epithelial-Mesenchymal Transition; Estrogen Receptor alpha; Female; Gene Expression Regulation, Neoplastic; Humans; Hyaluronan Receptors; MCF-7 Cells; Membrane Glycoproteins; Neoplasm Invasiveness; Proto-Oncogene Proteins; Receptor, Notch1; Receptor, Notch2; Receptor, Notch4; Receptors, Notch; RNA Interference; RNA, Small Interfering; Selective Estrogen Receptor Modulators; Spheroids, Cellular; Tamoxifen; Tetrahydronaphthalenes; Tumor Cells, Cultured; Valine

Notch signaling mediates breast cancer cell survival and chemoresistance. In this report, we aimed to evaluate the antitumor efficacy of PF-03084014 in combination with docetaxel in triple-negative breast cancer models. The mechanism of action was investigated. PF-03084014 significantly enhanced the antitumor activity of docetaxel in multiple xenograft models including HCC1599, MDA-MB-231Luc, and AA1077. Docetaxel activated the Notch pathway by increasing the cleaved Notch1 intracellular domain and suppressing the endogenous Notch inhibitor NUMB. PF-03084014 used in combination with docetaxel reversed these effects and demonstrated early-stage synergistic apoptosis. Docetaxel elicited chemoresistance by elevating cytokine release and expression of survivin and induced an endothelial mesenchymal transition (EMT) phenotype by increasing the expressions of Snail, Slug, and N-cadherin. When reimplanted, the docetaxel-residual cells not only became much more tumorigenic, as evidenced by a higher fraction of tumor-initiating cells (TICs), but also showed higher metastatic potential compared with nontreated cells, leading to significantly shortened survival. In contrast, PF-03084014 was able to suppress expression of survivin and MCL1, reduce ABCB1 and ABCC2, upregulate BIM, reverse the EMT phenotype, and diminish the TICs. Additionally, the changes to the ALDH(+) and CD133(+)/CD44(+) subpopulations following therapy corresponded with the TIC self-renewal assay outcome. In summary, PF-03084014 demonstrated synergistic effects with docetaxel through multiple mechanisms. This work provides a strong preclinical rationale for the clinical utility of PF-03084014 to improve taxane therapy.

Topics: AC133 Antigen; Amyloid Precursor Protein Secretases; Animals; Antigens, CD; Antineoplastic Combined Chemotherapy Protocols; Biomarkers, Tumor; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cytokines; Docetaxel; Drug Resistance, Neoplasm; Drug Synergism; Epithelial-Mesenchymal Transition; Female; Glycoproteins; Humans; Hyaluronan Receptors; Membrane Proteins; Mice; Mice, SCID; Multidrug Resistance-Associated Protein 2; Nerve Tissue Proteins; Peptides; Receptor, Notch1; Signal Transduction; Taxoids; Tetrahydronaphthalenes; Time Factors; Valine; Xenograft Model Antitumor Assays

We aimed to assess the biologic activity of PF-03084014 in breast xenograft models. The biomarkers for mechanism and patient stratification were also explored.. The in vitro and in vivo properties of PF-03084014 were investigated. The mRNA expressions of 40 key Notch pathway genes at baseline or after treatment were analyzed to link with the antitumor efficacy of PF-03084014 in a panel of breast cancer xenograft models.. In vitro, PF-03084014 exhibited activity against tumor cell migration, endothelial cell tube formation, and mammosphere formation. In vivo, we observed apoptosis, antiproliferation, reduced tumor cell self-renewal ability, impaired tumor vasculature, and decreased metastasis activity after the treatment of PF-03084014. PF-03084014 treatment displayed significant antitumor activity in 10 of the 18 breast xenograft models. However, the antitumor efficacy in most models did not correlate with the in vitro antiproliferation results in the corresponding cell lines, suggesting the critical involvement of tumor microenvironment during Notch activation. In the tested breast xenograft models, the baseline expressions of the Notch receptors, ligands, and the cleaved Notch1 failed to predict the antitumor response to PF-03084014, whereas several Notch pathway target genes, including HEY2, HES4, and HES3, strongly corresponded with the response with a P value less than 0.01. Many of the best molecular predictors of response were also significantly modulated following PF-03084014 treatment.. PF-03084014 showed antitumor and antimetastatic properties via pleiotropic mechanisms. The Notch pathway downstream genes may be used to predict the antitumor activity of PF-03084014 and enrich for responders among breast cancer patients.

Topics: Amyloid Precursor Protein Secretases; Antineoplastic Agents; Biomarkers, Tumor; Breast Neoplasms; Cell Line, Tumor; Cluster Analysis; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Human Umbilical Vein Endothelial Cells; Humans; Neoplasm Metastasis; Receptors, Notch; Signal Transduction; Tetrahydronaphthalenes; Valine; Xenograft Model Antitumor Assays