scholarly journals Control of MYC-dependent apoptotic threshold by a co-amplified ubiquitin E3 ligase UBR5

2019 ◽  
Author(s):  
Xi Qiao ◽  
Ying Liu ◽  
Maria Llamazares Prada ◽  
Abhishekh Gupta ◽  
Alok Jaiswal ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Protein Expression ◽  
Cancer Cells ◽  
Ubiquitin Ligase ◽  
Breast Cancer Cells ◽  
Human Cancer ◽  
Cancer Therapeutics ◽  
Cancer Tissue ◽  
Basal Type

AbstractMYC protein expression has to be tightly controlled to allow for maximal cell proliferation without inducing apoptosis. Here we discover UBR5 as a novel MYC ubiquitin ligase and demonstrate how it functions as a molecular rheostat to prevent excess accumulation of MYC protein. UBR5 effects on MYC protein stability are independent on N-terminal FBW7 degron of MYC. Endogenous UBR5 inhibition induces MYC protein expression and activates MYC target genes. Moreover, UBR5 governs MYC-dependent phenotypes in vivo in Drosophila. In cancer cells, UBR5-mediated MYC protein suppression diminishes cell killing activity of cancer therapeutics. Further, we demonstrate that UBR5 dominates MYC protein expression at the single-cell level in human basal-type breast cancer tissue. Myc and Ubr5 are co-amplified in MYC-driven human cancer types, and UBR5 controls MYC-mediated apoptotic threshold in co-amplified basal type breast cancer cells. In summary, UBR5 is a novel MYC ubiquitin ligase and an endogenous rheostat for MYC protein expression in vivo. Clinically, expression of UBR5 may be important for protection of breast cancer cells from drug-induced, and MYC-dependent, apoptosis.

scholarly journals SAT-742 Characterising the Metabolism, Glucuronidation and Sulfation of C11-oxy C19 Steroids

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Therina Du Toit ◽  
Amanda C Swart
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Receptor Activation ◽  
In Vitro Models ◽  
In Vivo Studies ◽  
Cancer Tissue ◽  
Mcf 7

Abstract The metabolism of 11β-hydroxyandrostenedione (11OHA4), a major adrenal C19 steroid, was first characterised in our in vitro prostate models showing that 11OHA4, catalysed by 11βHSDs, 17βHSDs and 5α-reductases, yields potent androgens, 11keto-testosterone (11KT) and 11keto-dihydrotestosterone (11KDHT) in the 11OHA4-pathway [1]. Findings have since led to the analysis of C11-oxy steroids in PCOS, CAH and 21OHD. However, the only circulating C11-oxy steroids included to date have been 11OHA4, 11keto-androstenedione (11KA4), 11β-hydroxytestosterone (11OHT) and 11KT, with 11KT reported as the only potent androgen produced from 11OHA4. We have identified higher levels of 11KDHT compared to 11KT in prostate cancer tissue and benign prostatic hyperplasia tissue and serum, with data suggesting impeded glucuronidation of the C11-oxy androgens [2,3]. The assessment of 11KDHT and the inactivation/conjugation of the C11-oxy steroids in clinical conditions is therefore crucial. We investigated the metabolism of testosterone, 11KT, 11OHT, dihydrotestosterone, 11KDHT and 11OHDHT in JEG-3 placenta choriocarcinoma, MCF-7 BUS and T-47D breast cancer cells, focusing on glucuronidation and sulfation. Steroids were assayed at 1 µM and metabolites were quantified using UPC2-MS/MS. Conjugated steroids were not detected in JEG-3 cells with DHT (0.6 µM remaining) metabolised to 5α-androstane-3α,17β-diol and androsterone (AST), and 11KDHT (0.9 µM remaining) to 11OHAST and 11KAST. 11OHA4 was converted to 11KA4 (12%) and 11KT (2.5%); and 11KT to 11KDHT (14%). In MCF-7 BUS cells, DHT was significantly glucuronidated, whereas 11KDHT was not. 11KAST was the only steroid in the MCF-7 BUS and T-47D cells that was significantly sulfated (p<0.05). In parallel we investigated sulfation in the LNCaP prostate model. Comparing sulfated to glucuronidated levels, only DHT was sulfated, 26%. Analysis showed that C19 steroids were significantly conjugated (glucuronidated + sulfated) compared to the C11-oxy C19 steroids. As there exists an intricate interplay between steroid production and inactivation, impacting pre- and post-receptor activation, efficient conjugation would limit adverse downstream effects. Our data demonstrates the production and impeded conjugation of active C11-oxy C19 steroids, allowing the prolonged presence of androgenic steroids in the cellular microenvironment. Identified for the first time is the 11OHA4-pathway in placenta and breast cancer cells, and the sulfation of 11KAST. Characterising steroidogenic pathways in in vitro models paves the direction for in vivo studies associated with characterising clinical disorders and disease, which the C11-oxy C19 steroids and their intermediates, including inactivated and conjugated end-products, have highlighted. [1] Bloem, et al. JSBMB 2015, 153; [2] Du Toit & Swart. MCE 2018, 461; [3] Du Toit & Swart, JSBMB 2020, 105497.

scholarly journals JAC1 suppresses proliferation of breast cancer through the JWA/p38/SMURF1/HER2 signaling

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yanlin Ren ◽  
Dongyin Chen ◽  
Zurong Zhai ◽  
Junjie Chen ◽  
Aiping Li ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Ubiquitin Ligase ◽  
Breast Cancer Cells ◽  
E3 Ubiquitin Ligase ◽  
Her2 Positive ◽  
Her2 Positive Breast Cancer ◽  
Positive Breast Cancer

AbstractThe overexpression of HER2 is associated with a malignant proliferation of breast cancer. In this study, we developed a non-cytotoxic JWA gene activating compound 1 (JAC1) to inhibit the proliferation of HER2-positive breast cancer cells in vitro and in vivo experimental models. JAC1 increased the ubiquitination of HER2 at the K716 site through the E3 ubiquitin ligase SMURF1 which was due to the decreased expression of NEDD4, the E3 ubiquitin ligase of SMURF1. In conclusion, JAC1 suppresses the proliferation of HER2-positive breast cancer cells through the JWA triggered HER2 ubiquitination signaling. JAC1 may serve as a potential therapeutic agent for HER2-positive breast cancer.

scholarly journals Role of c-Met/β1 integrin complex in the metastatic cascade

2020 ◽  
Author(s):  
Darryl Lau ◽  
Harsh Wadhwa ◽  
Sweta Sudhir ◽  
Saket Jain ◽  
Ankush Chandra ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Human Cancer ◽  
Β1 Integrin ◽  
Tissue Specific ◽  
Metastatic Cascade ◽  
Kinase C

ABSTRACTMetastases cause 90% of human cancer deaths. The metastatic cascade involves local invasion, intravasation, extravasation, metastatic site colonization, and proliferation. While individual mediators of these processes have been investigated, interactions between these mediators remain less well defined. We previously identified a structural complex between receptor tyrosine kinase c-Met and β1 integrin in metastases. Using novel cell culture and in vivo assays, we found that c-Met/β1 complex induction promotes breast cancer intravasation and adhesion to the vessel wall, but does not increase extravasation. These effects may be driven by the ability of the c-Met/β1 complex to increase mesenchymal and stem cell characteristics. Multiplex transcriptomic analysis revealed upregulated Wnt and hedgehog pathways after c-Met/β1 complex induction. A β1 integrin point mutation that prevented binding to c-Met reduced intravasation. OS2966, a therapeutic antibody disrupting c-Met/β1 binding, decreased invasion and mesenchymal gene expression and morphology of breast cancer cells. Bone-seeking breast cancer cells exhibited higher c-Met/β1 complex levels than parental controls and preferentially adhere to tissue-specific matrix. Patient bone metastases demonstrated higher c-Met/β1 levels than brain metastases. Thus, the c-Met/β1 complex drives breast cancer cell intravasation and preferential affinity for bone tissue-specific matrix. Pharmacological targeting of the complex may prevent metastases, particularly osseous metastases.

scholarly journals LncRNA EGFR-AS1 Regulates Breast Cancer Cells Function and Sensitivity to Docetaxel Via the miR-149-5p/ELP5 Axis

2021 ◽  
Author(s):  
Shiping Li ◽  
Xiaoyi Mi ◽  
Mingfang Sun ◽  
Jie Zhang ◽  
Miaomiao Hao ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Western Blotting ◽  
Breast Cancer Cells ◽  
Breast Cancer Tissue ◽  
Luciferase Reporter ◽  
Cancer Tissue ◽  
Cancer Tissues

Abstract Background: Recently, an increasing number of studies have focused on investigating long non-coding RNAs (lncRNAs) and their role in regulating the progression of various cancer types. However, the biological effects and underlying mechanisms of EGFR-AS1, a typical lncRNA, remain largely unclear in breast cancer.Methods: Differential expression of EGFR-AS1 in breast cancer tissue was analyzed using an integrative database and verified in breast cancer tissue samples and cells via real-time PCR analysis and western blotting analysis. The tumor promoter role of EGFR-AS1 in breast cancer cells was determined through MTT, EDU analysis, colony formation and transwell assays,and the effect of EGFR-AS1 on docetaxel drug sensitivity was examined. We then performed bioinformatic analysis and the dual-luciferase reporter assay to identify the binding sites of EGFR-AS1/miR-149-5p and miR-149-5p/ELP5. Results from western blotting and biological function studies provided insights into whether the EGFR-AS1/miR-149-5p/ELP5 axis regulates breast cancer development in vitro and in vivo. Results: EGFR-AS1 is upregulated in breast cancer tissues and cells and promotes the progression of breast cancer cells both in vitro and in vivo. Moreover, miR-149-5p is downregulated in breast cancer tissues and cell lines. Mechanistically, EGFR-AS1 regulates ELP5 levels by sponging miR-149-5p, thereby affecting cell progression and promoting epithelial-to-mesenchymal transition. Hence, the EGFR-AS1/miR-149-5p/ELP5 axis is involved in breast cancer proliferation, migration, invasion, and resistance to the chemotherapeutic drug, docetaxel, in breast cancer cells. Conclusions: EGFR-AS1 sponges miR-149-5p to affect the expression level of ELP5 ultimately acting as a new tumor promotor in breast cancer. This study provides novel insights into diagnostic and docetaxel-related chemotherapy targets for breast cancer.

scholarly journals Pyrotinib Sensitizes 5-Fluorouracil-Resistant HER2+ Breast Cancer Cells to 5-Fluorouracil

2020 ◽  
Vol 28 (5) ◽  
pp. 519-531
Author(s):  
Jianing Yi ◽  
Shuai Chen ◽  
Pingyong Yi ◽  
Jinlin Luo ◽  
Meng Fang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Protein Expression ◽  
Cancer Cells ◽  
Cell Lines ◽  
Breast Cancer Cells ◽  
Kinase Inhibitor ◽  
Parental Cell ◽  
Expression Levels ◽  
Her2 Breast Cancer

5-Fluorouracil (5-FU) is a widely used chemotherapeutic agent for breast cancer. However, acquired chemoresistance leads to a loss of its efficacy; methods to reverse are urgently needed. Some studies have shown that pyrotinib, an ErbB receptor tyrosine kinase inhibitor, is effective against HER2+ breast cancer. However, whether pyrotinib sensitizes 5-FU-resistant breast cancer cells to 5-FU is unknown. We hypothesized that the combination of pyrotinib and 5-FU would show synergistic antitumor activity, and pyrotinib could reverse 5-FU resistance in HER2+ breast cancer cells in vitro and in vivo. Our data showed that pyrotinib inhibited the growth of 5-FU-resistant SKBR-3/FU and MDA-MB-453/FU cell lines and the parental cell lines. 5-FU remarkably suppressed the growth of SKBR-3 and MAD-MB-453 cells. However, SKBR-3/FU and MAD-MB-453/FU cells showed resistance to 5-FU. A combination of pyrotinib and 5-FU resulted in the synergistic inhibition of the growth of the 5-FU-resistant SKBR-3/FU and MDA-MB-453/FU cell lines and the parental cell lines. Pyrotinib decreased significantly the IC50 values of 5-FU and the thymidylate synthase (TS) mRNA expression levels in the 5-FU-resistant SKBR-3/FU and MDA-MB-453/FU cell lines and the parental cell lines and increased significantly the intracellular concentration of 5-FU in SKBR-3/FU and MDA-MB-453/FU cells. In addition, pyrotinib reduced the ABCG2 mRNA and protein expression levels in SKBR-3/FU and MDA-MB-453/FU cells and downregulated the protein expression levels of pAKT, pHER2, and pHER4 in all four cell lines. After TS or ABCG2 in 5-FU-resistant breast cancer cells was knocked down, the sensitivity of SKBR-3/FU and MDA-MB-453/FU cells to 5-FU was restored. Moreover, in vivo experiments demonstrated that pyrotinib in combination with 5-FU more effectively inhibited SKBR-3/FU tumor growth than either pyrotinib or 5-FU alone. In conclusion, our findings suggest that pyrotinib could restore sensitivity of 5-FU-resistant HER2+ breast cancer cells to 5-FU through downregulating the expression levels of TS and ABCG2.

In vivo monitoring of intranuclear p27kip1 protein expression in breast cancer cells during trastuzumab (Herceptin) therapy

2009 ◽  
Vol 36 (7) ◽  
pp. 811-819 ◽  
Author(s):  
Bart Cornelissen ◽  
Veerle Kersemans ◽  
Kristin McLarty ◽  
Lara Tran ◽  
Katherine A. Vallis ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Protein Expression ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
In Vivo Monitoring ◽  
P27kip1 Protein

scholarly journals The Agonist of JWA Gene JAC1 Suppresses Proliferation of Breast Cancer Through the JWA/p38/SMURF1/HER2 Signaling

2020 ◽  
Author(s):  
Yanlin Ren ◽  
Dongyin Chen ◽  
Junjie Chen ◽  
Zurong Zhai ◽  
Aiping Li ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Ubiquitin Ligase ◽  
Breast Cancer Cells ◽  
E3 Ubiquitin Ligase ◽  
Her2 Positive ◽  
Her2 Positive Breast Cancer ◽  
Her2 Signaling ◽  
Positive Breast Cancer

Abstract Background The overexpression of HER2 is associated with malignant proliferation and invasiveness in breast cancer. Although HER2-targeting drugs have been clinically applied for cancer treatment, none of them could reduce overexpressed HER2. In this study, we reported that JAC1 could suppress proliferation of breast cancer cells via degrading HER2. Methods JWA-HER2 association was analyzed by IHC in 90 paired cases of breast cancer and adjacent non-cancerous tissues. Regulatory effect of JAC1, the agonist of JWA gene, on HER2-positive breast cancer cells was studied using colony formation assay. The effect of JAC1 on the localization of HER2 was detected by immunofluorescence microscopy assay. Western blotting, RT-PCR and immunoprecipitation assay were utilized to investigate the mechanisms of JWA on regulating HER2. Finally, xenograft mouse models were established in nude mice using BT474 cells to confirm the effect of JAC1 in vivo. Results JAC1, a small molecule agonist of JWA gene, dose-dependently suppressed proliferation in HER2-positive breast cancer in vitro and in vivo through degrading HER2. The mechanistic evidences showed that JAC1 increased the ubiquitination of HER2 at the K716 through the E3 ubiquitin ligase SMURF1. Furthermore, SMURF1 was activated due to reduced expression of NEDD4, an E3 ubiquitin ligase for SMURF1 through the JWA-p38-GATA-1-NEDD4 axis. Conclusions JAC1 suppresses the proliferation in HER2-positive breast cancer through the JWA/p38/GATA-1/NEDD4/SMURF1/HER2 signaling. JAC1 may serve as a novel therapeutic agent to breast cancer.

scholarly journals Gab2 Ablation Reverses the Stemness of HER2-Overexpressing Breast Cancer Cells

2018 ◽  
Vol 50 (1) ◽  
pp. 52-65 ◽  
Author(s):  
Peng Zhang ◽  
Yiying Chen ◽  
Miaomiao Gong ◽  
Zhumei Zhuang ◽  
Yueyue Wang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Growth ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Human Cancer ◽  
Mammary Tumorigenesis ◽  
Breast Cancer Patients ◽  
Tumor Growth And Metastasis ◽  
Sphere Formation

Background/Aims: HER2 has been implicated in mammary tumorigenesis as well as aggressive tumor growth and metastasis. Its overexpression is related to a poor prognosis and chemoresistance in breast cancer patients. Although Grb2-associated binding protein 2 (Gab2) is important in the development and progression of human cancer, its effects and mechanisms in HER2-overexpressing breast cancer are unclear. Methods: Clone formation and MTT assays were used to examine cell proliferation. To detect the effect of Gab2 on the stemness of breast cancer cells, we used flow cytometry, a sphere formation assay, real-time PCR, and western blot. An animal model was created to validate the effect of Gab2 on tumor growth in vivo. Tissue slides were analyzed by immunohistochemistry. Results: Knockdown of Gab2 suppressed PI3K/AKT and MAPK/ERK pathway activity. Gab2 ablation also reduced the stemness of HER2-overexpressing breast cancer cells. In vivo, knockdown of Gab2 inhibited tumor growth. Conclusion: This study unveils a potential function of Gab2 in HER2-overexpressing breast cancer cells. Gab2 might be a potential target in the clinical therapy of HER2-overexpressing breast carcinoma.

scholarly journals CSIG-04. ROLE OF c-Met/β1 INTEGRIN COMPLEX IN THE METASTATIC CASCADE

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii28-ii28
Author(s):  
Sweta Sudhir ◽  
Darryl Lau ◽  
Harsh Wadhwa ◽  
Saket Jain ◽  
Ankush Chandra ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Human Cancer ◽  
Β1 Integrin ◽  
Blocking Antibody ◽  
Tissue Specific ◽  
Metastatic Cascade

Abstract Metastases cause 90% of human cancer deaths. The metastatic cascade involves 5 steps: local invasion, intravasation, extravasation, metastatic site colonization, and proliferation. While individual mediators of these processes have been investigated, interactions between these mediators remain less well defined. We previously identified a structural complex between receptor tyrosine kinase c-Met and β1 integrin in metastases that form under certain biological and therapeutic inducers, including bevacizumab. Using novel cell culture and in vivo assays, we found that c-Met/β1 complex induction promotes breast cancer intravasation and adhesion to the vessel wall but does not increase extravasation. These effects may be driven by the ability of the c-Met/β1 complex to increase mesenchymal and stem cell characteristics in breast cancer cells. Multiplex transcriptomic analysis revealed upregulated Wnt and hedgehog pathways after c-Met/β1 complex induction in breast cancer cells. We subsequently used CRISPR to introduce a β1 integrin point mutation that prevented binding to c-Met and led to reduced intravasation, confirming the importance of c-Met/β1 integrin binding for the metastatic cascade. OS2966, a therapeutic B1 integrin blocking antibody, disrupted c-Met/β1 binding as well, and decreased invasion, mesenchymal gene expression, and mesenchymal morphology of breast cancer cells. Bone-seeking breast cancer cells exhibited higher c-Met/β1 complex levels than parental controls and preferentially adhere to tissue-specific matrix. Patient bone metastases demonstrated higher c-Met/β1 complex levels than brain metastases. Thus, our research suggests the c-Met/β1 complex drives breast cancer cell intravasation and preferential affinity for bone tissue-specific matrix. Pharmacological targeting of the complex may prevent metastases, particularly osseous metastases.

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