scholarly journals Altered RNA splicing initiates the viral mimicry response from inverted SINEs following type I PRMT inhibition in Triple-Negative Breast Cancer

2021 ◽  
Author(s):  
Cheryl Arrowsmith ◽  
Qin Wu ◽  
David Nie ◽  
Wail alawi ◽  
Jennifer Cruickshank ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Breast Cancer Subtype ◽  
Arginine Methylation ◽  
Interferon Response ◽  
Type I

Abstract Triple negative breast cancer (TNBC) is the most aggressive breast cancer subtype with the worst prognosis and few effective therapies. Here, we undertook a screen of epigenetic chemical probes to systematically uncover the epigenetic regulators critical for TNBC growth. We identified MS023, an inhibitor of type I protein arginine methyltransferases (PRMTs), as having anti-tumor growth activity in TNBC in vitro and in vivo. Pathway analysis of TNBC cell lines indicates that the activation of interferon responses pre- and post-MS023 treatment is a functional biomarker and determinant of response; and these observations extend to a panel of patient-derived organoids. Inhibition of type I PRMT triggers an interferon response through the antiviral defense pathway with the induction of double-stranded RNA (dsRNA). The observed dsRNA accumulation is derived, at least in part, from inverted-repeat Alus (IR-Alus), many of which are expressed from retained introns induced by MS023, which inhibits arginine methylation of RNA-binding proteins and alters mRNA splicing machinery. Together, our results represent a shift in understanding the anti-tumor mechanism of type I PRMT inhibitors and provide a novel rationale and biomarker approach for the clinical development of type I PRMT inhibitors.

scholarly journals Targeting PML in triple negative breast cancer elicits growth suppression and senescence

2019 ◽  
Vol 27 (4) ◽  
pp. 1186-1199 ◽  
Author(s):  
Leire Arreal ◽  
Marco Piva ◽  
Sonia Fernández ◽  
Ajinkya Revandkar ◽  
Ariane Schaub- Clerigué ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Cells ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Cell Function ◽  
Breast Cancer Subtype ◽  
Growth Arrest ◽  
Promoter Regions

Abstract Oncogene addiction postulates that the survival and growth of certain tumor cells is dependent upon the activity of one oncogene, despite their multiple genetic and epigenetic abnormalities. This phenomenon provides a foundation for molecular targeted therapy and a rationale for oncogene-based stratification. We have previously reported that the Promyelocytic Leukemia protein (PML) is upregulated in triple negative breast cancer (TNBC) and it regulates cancer-initiating cell function, thus suggesting that this protein can be therapeutically targeted in combination with PML-based stratification. However, the effects of PML perturbation on the bulk of tumor cells remained poorly understood. Here we demonstrate that TNBC cells are addicted to the expression of this nuclear protein. PML inhibition led to a remarkable growth arrest combined with features of senescence in vitro and in vivo. Mechanistically, the growth arrest and senescence were associated to a decrease in MYC and PIM1 kinase levels, with the subsequent accumulation of CDKN1B (p27), a trigger of senescence. In line with this notion, we found that PML is associated to the promoter regions of MYC and PIM1, consistent with their direct correlation in breast cancer specimens. Altogether, our results provide a feasible explanation for the functional similarities of MYC, PIM1, and PML in TNBC and encourage further study of PML targeting strategies for the treatment of this breast cancer subtype.

scholarly journals Depletion of CD206+ tumour macrophages by mUNO targeted nanoconjugate inhibits tumourigenesis and dissemination in triple negative breast cancer

2021 ◽  
Author(s):  
Anni Lepland ◽  
Alessio Malfanti ◽  
Uku Haljasorg ◽  
Eliana Asciutto ◽  
Monica Pickholz ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Breast Cancer Subtype ◽  
Foxp3 Expression ◽  
Tumour Microenvironment ◽  
Solid Tumours ◽  
Fluorescent Reporter

Abstract Chemotherapy is the standard of care for patients with triple negative breast cancer (TNBC), an aggressive breast cancer subtype with a poor prognosis. In many solid tumours, M2-skewed tumour-associated macrophages (TAMs) are known to promote progression, immunosuppression, relapse, and dissemination of the malignant disease. Although TAM depletion has been explored as an anticancer strategy, the currently available TAM depleting compounds suffer from poor efficacy and dose-limiting side effects. Here, we develop of a novel TAM-depleting agent that specifically targets CD206+ macrophages and show that it is efficacious as an anti-TNBC agent and well tolerated. This new TAM-depleting compound, called “OximUNO”, is a star-shaped polyglutamate decorated with the CD206-targeting peptide mUNO and carrying doxorubicin through a pH-responsive linker. In the orthotopic and experimental metastases of TNBC, fluorescent reporter mUNO-guided polyglutamate construct homed to CD206+ macrophages in the primary cancer lesions and at the sites of metastases. OximUNO displayed enhanced cytotoxicity towards primary M2 macrophages in vitro and exhibited no acute liver or kidney toxicity in vivo. In TNBC mouse models, OximUNO reduced the progression of primary breast cancer lesions and metastatic dissemination of malignant cells. Treatment with OximUNO had an immunomodulatory effect on the tumour microenvironment: besides reducing the number of CD206+ TAMs, it resulted in increased ratio of the CD8/FOXP3 expression. These studies suggest the potential utility of OximUNO based CD206+ TAM depletion strategies for the treatment of TNBC, and possibly, other types of solid tumours.

scholarly journals Circular HER2 RNA positive triple negative breast cancer is sensitive to Pertuzumab

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Jie Li ◽  
Maoguang Ma ◽  
Xuesong Yang ◽  
Maolei Zhang ◽  
Jingyan Luo ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Breast Cancer Subtype ◽  
Critical Role ◽  
Amino Acid Sequences ◽  
Clinical Samples ◽  
Novel Protein

Abstract Background Triple negative breast cancer (TNBC) remains the most challenging breast cancer subtype so far. Specific therapeutic approaches have rarely achieved clinical improvements in treatment of TNBC patients and effective molecular biomarkers are largely unknown. Methods We used paired TNBC samples and high throughput RNA sequencing to identify differentially expressed circRNAs. Sucrose gradient polysome fractionation assay, antibody and Mass spectra were used to validate active circRNA translation. The novel protein function was validated in vitro and in vivo by gain or loss of function assays. Mechanistic results were concluded by immunoprecipitation analyses and kinase activity assay. Results Circular HER2 RNA (circ-HER2) encoded a novel protein, HER2–103. Unexpectedly, while HER2 mRNA and protein were barely detected, circ-HER2/HER2–103 was expressed in ~ 30% TNBC clinical samples. Circ-HER2/HER2–103 positive TNBC patients harbored worse overall prognosis than circ-HER2/HER2–103 negative patients. Knockdown circ-HER2 inhibited TNBC cells proliferation, invasion and tumorigenesis in vitro and in vivo, suggesting the critical role of circ-HER2/HER2–103 in TNBC tumorigenicity. Mechanistically, HER2–103 promoted homo/hetero dimerization of epidermal growth factor receptor (EGFR)/HER3, sustained AKT phosphorylation and downstream malignant phenotypes. Furthermore, HER2–103 shared most of the same amino acid sequences as HER2 CR1 domain which could be antagonized by Pertuzumab, a clinical used HER2 antibody. Pertuzumab markedly attenuated in vivo tumorigenicity of circ-HER2/HER2–103 expressing TNBC cells but showed no effects in circ-HER2/HER2–103 negative TNBC cells. Conclusion Our results not only demonstrated that certain TNBCs were not truly ‘HER2 negative’ but also highlighted the clinical implications of Pertuzumab in circ-HER2/HER2–103 expressing TNBC patients.

Effect of RNA-binding protein MSI2 deficiency on progression in triple-negative breast cancer via stabilizing TP53INP1.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e12555-e12555
Author(s):  
Ping Wei ◽  
Ming Li ◽  
Wentao Yang ◽  
Xiaoyan Zhou
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Cell Invasion ◽  
Triple Negative ◽  
Rna Binding ◽  
Rna Binding Protein ◽  
Normal Tissues ◽  
Tnbc Cell ◽  
Proliferation And Invasion

e12555 Background: The RNA-binding protein Musashi-2 (MSI2) has been implicated in the tumorigenesis and tumor progression of human cancers. This study investigated the clinical significance of MSI2 and the potential molecular mechanisms involved in triple-negative breast cancer (TNBC) progression. Methods: The Illumina sequencing platform was used to analyze the mRNA transcriptome in TNBC vs. normal tissues, while quantitative reverse transcription–polymerase chain reaction and immunohistochemistry validated MSI2 expression in breast cancer tissues and the effects of MSI2 on TNBC cells were assayed in vitro and in viv o. RNA immunoprecipitation (RIP) DNA and RNA sequencing was performed to identify the potential MSI2-targeted mRNAs. RIP and luciferase analyses were used to confirm the mRNA targets of MSI2. Results: MSI2 expression was significantly downregulated in TNBC vs. normal tissues and was associated with a poor overall survival of patients. MSI2 overexpression in vitro and in vivo inhibited TNBC cell proliferation and invasion as well as the extracellular signal-regulated kinase 1/2 (ERK1/2) activity. Molecularly, MSI2 expression promoted the stability of TP53INP1 mRNA by its interaction with the TP53INP1 mRNA 3ʹ-untranslated region. Furthermore, knockdown of TP53INP1 expression was able to reverse MSI2-induced suppression of TNBC cell invasion, whereas ectopic expression of TP53INP1 and inhibition of the ERK1/2 activity blocked MSI2 knockdown-induced TNBC cell invasion. Conclusions: The current study demonstrated that downregulated MSI2 expression was associated with TNBC progression and a poor prognosis and that MSI2 expression inhibited TNBC proliferation and invasion by induction of TP53INP1 stability and inhibition of ERK1/2 activity.

scholarly journals MCPIP1-mediated NFIC alternative splicing inhibits proliferation of triple-negative breast cancer via cyclin D1-Rb-E2F1 axis

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Fengxia Chen ◽  
Qingqing Wang ◽  
Xiaoyan Yu ◽  
Ningning Yang ◽  
Yuan Wang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Overall Survival ◽  
Alternative Splicing ◽  
Cyclin D1 ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Negative Regulator ◽  
Breast Epithelial Cell

AbstractTriple-negative breast cancer (TNBC) is the most aggressive subtype with the worst prognosis and the highest metastatic and recurrence potential, which represents 15–20% of all breast cancers in Chinese females, and the 5-year overall survival rate is about 80% in Chinese women. Recently, emerging evidence suggested that aberrant alternative splicing (AS) plays a crucial role in tumorigenesis and progression. AS is generally controlled by AS-associated RNA binding proteins (RBPs). Monocyte chemotactic protein induced protein 1 (MCPIP1), a zinc finger RBP, functions as a tumor suppressor in many cancers. Here, we showed that MCPIP1 was downregulated in 80 TNBC tissues and five TNBC cell lines compared to adjacent paracancerous tissues and one human immortalized breast epithelial cell line, while its high expression levels were associated with increased overall survival in TNBC patients. We demonstrated that MCPIP1 overexpression dramatically suppressed cell cycle progression and proliferation of TNBC cells in vitro and repressed tumor growth in vivo. Mechanistically, MCPIP1 was first demonstrated to act as a splicing factor to regulate AS in TNBC cells. Furthermore, we demonstrated that MCPIP1 modulated NFIC AS to promote CTF5 synthesis, which acted as a negative regulator in TNBC cells. Subsequently, we showed that CTF5 participated in MCPIP1-mediated antiproliferative effect by transcriptionally repressing cyclin D1 expression, as well as downregulating its downstream signaling targets p-Rb and E2F1. Conclusively, our findings provided novel insights into the anti-oncogenic mechanism of MCPIP1, suggesting that MCPIP1 could serve as an alternative treatment target in TNBC.

scholarly journals CX-5461 Enhances the Efficacy of APR-246 via Induction of DNA Damage and Replication Stress in Triple-Negative Breast Cancer

2021 ◽  
Vol 22 (11) ◽  
pp. 5782
Author(s):  
Ashwini Makhale ◽  
Devathri Nanayakkara ◽  
Prahlad Raninga ◽  
Kum Kum Khanna ◽  
Murugan Kalimutho
Keyword(s):  
Breast Cancer ◽  
Dna Damage ◽  
Triple Negative Breast Cancer ◽  
Combination Treatment ◽  
Triple Negative ◽  
Annexin V ◽  
Replication Stress ◽  
Breast Cancer Cell Lines ◽  
Combination Strategy

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer lacking targeted therapy. Here, we evaluated the anti-cancer activity of APR-246, a P53 activator, and CX-5461, a RNA polymerase I inhibitor, in the treatment of TNBC cells. We tested the efficacy of individual and combination therapy of CX-5461 and APR-246 in vitro, using a panel of breast cancer cell lines. Using publicly available breast cancer datasets, we found that components of RNA Pol I are predominately upregulated in basal-like breast cancer, compared to other subtypes, and this upregulation is associated with poor overall and relapse-free survival. Notably, we found that the treatment of breast cancer cells lines with CX-5461 significantly hampered cell proliferation and synergistically enhanced the efficacy of APR-246. The combination treatment significantly induced apoptosis that is associated with cleaved PARP and Caspase 3 along with Annexin V positivity. Likewise, we also found that combination treatment significantly induced DNA damage and replication stress in these cells. Our data provide a novel combination strategy by utilizing APR-246 in combination CX-5461 in killing TNBC cells that can be further developed into more effective therapy in TNBC therapeutic armamentarium.

scholarly journals GCH1 induces immunosuppression through metabolic reprogramming and IDO1 upregulation in triple-negative breast cancer

2021 ◽  
Vol 9 (7) ◽  
pp. e002383
Author(s):  
Jin-Li Wei ◽  
Si-Yu Wu ◽  
Yun-Song Yang ◽  
Yi Xiao ◽  
Xi Jin ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Molecular Taxonomy ◽  
Underlying Mechanism ◽  
Metabolic Reprogramming ◽  
Sequencing Data ◽  
Aryl Hydrocarbon

PurposeRegulatory T cells (Tregs) heavily infiltrate triple-negative breast cancer (TNBC), and their accumulation is affected by the metabolic reprogramming in cancer cells. In the present study, we sought to identify cancer cell-intrinsic metabolic modulators correlating with Tregs infiltration in TNBC.Experimental designUsing the RNA-sequencing data from our institute (n=360) and the Molecular Taxonomy of Breast Cancer International Consortium TNBC cohort (n=320), we calculated the abundance of Tregs in each sample and evaluated the correlation between gene expression levels and Tregs infiltration. Then, in vivo and in vitro experiments were performed to verify the correlation and explore the underlying mechanism.ResultsWe revealed that GTP cyclohydrolase 1 (GCH1) expression was positively correlated with Tregs infiltration and high GCH1 expression was associated with reduced overall survival in TNBC. In vivo and in vitro experiments showed that GCH1 increased Tregs infiltration, decreased apoptosis, and elevated the programmed cell death-1 (PD-1)-positive fraction. Metabolomics analysis indicated that GCH1 overexpression reprogrammed tryptophan metabolism, resulting in L-5-hydroxytryptophan (5-HTP) accumulation in the cytoplasm accompanied by kynurenine accumulation and tryptophan reduction in the supernatant. Subsequently, aryl hydrocarbon receptor, activated by 5-HTP, bound to the promoter of indoleamine 2,3-dioxygenase 1 (IDO1) and thus enhanced the transcription of IDO1. Furthermore, the inhibition of GCH1 by 2,4-diamino-6-hydroxypyrimidine (DAHP) decreased IDO1 expression, attenuated tumor growth, and enhanced the tumor response to PD-1 blockade immunotherapy.ConclusionsTumor-cell-intrinsic GCH1 induced immunosuppression through metabolic reprogramming and IDO1 upregulation in TNBC. Inhibition of GCH1 by DAHP serves as a potential immunometabolic strategy in TNBC.

scholarly journals Selection of aptamers against triple negative breast cancer cells using high throughput sequencing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Débora Ferreira ◽  
Joaquim Barbosa ◽  
Diana A. Sousa ◽  
Cátia Silva ◽  
Luís D. R. Melo ◽  
...  
Keyword(s):  
Breast Cancer ◽  
High Throughput ◽  
Triple Negative Breast Cancer ◽  
High Throughput Sequencing ◽  
Triple Negative ◽  
Metastatic Breast ◽  
Target Cells ◽  
Cancer Tissue ◽  
Surface Receptors

AbstractTriple-negative breast cancer is the most aggressive subtype of invasive breast cancer with a poor prognosis and no approved targeted therapy. Hence, the identification of new and specific ligands is essential to develop novel targeted therapies. In this study, we aimed to identify new aptamers that bind to highly metastatic breast cancer MDA-MB-231 cells using the cell-SELEX technology aided by high throughput sequencing. After 8 cycles of selection, the aptamer pool was sequenced and the 25 most frequent sequences were aligned for homology within their variable core region, plotted according to their free energy and the key nucleotides possibly involved in the target binding site were analyzed. Two aptamer candidates, Apt1 and Apt2, binding specifically to the target cells with $$K_{d}$$ K d values of 44.3 ± 13.3 nM and 17.7 ± 2.7 nM, respectively, were further validated. The binding analysis clearly showed their specificity to MDA-MB-231 cells and suggested the targeting of cell surface receptors. Additionally, Apt2 revealed no toxicity in vitro and showed potential translational application due to its affinity to breast cancer tissue sections. Overall, the results suggest that Apt2 is a promising candidate to be used in triple-negative breast cancer treatment and/or diagnosis.

scholarly journals Edelfosine nanoemulsions inhibit tumor growth of triple negative breast cancer in zebrafish xenograft model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sofia M. Saraiva ◽  
Carlha Gutiérrez-Lovera ◽  
Jeannette Martínez-Val ◽  
Sainza Lores ◽  
Belén L. Bouzo ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Growth ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Xenograft Model ◽  
Skin Barrier ◽  
Zebrafish Embryos ◽  
Biorelevant Media

AbstractTriple negative breast cancer (TNBC) is known for being very aggressive, heterogeneous and highly metastatic. The standard of care treatment is still chemotherapy, with adjacent toxicity and low efficacy, highlighting the need for alternative and more effective therapeutic strategies. Edelfosine, an alkyl-lysophospholipid, has proved to be a promising therapy for several cancer types, upon delivery in lipid nanoparticles. Therefore, the objective of this work was to explore the potential of edelfosine for the treatment of TNBC. Edelfosine nanoemulsions (ET-NEs) composed by edelfosine, Miglyol 812 and phosphatidylcholine as excipients, due to their good safety profile, presented an average size of about 120 nm and a neutral zeta potential, and were stable in biorelevant media. The ability of ET-NEs to interrupt tumor growth in TNBC was demonstrated both in vitro, using a highly aggressive and invasive TNBC cell line, and in vivo, using zebrafish embryos. Importantly, ET-NEs were able to penetrate through the skin barrier of MDA-MB 231 xenografted zebrafish embryos, into the yolk sac, leading to an effective decrease of highly aggressive and invasive tumoral cells’ proliferation. Altogether the results demonstrate the potential of ET-NEs for the development of new therapeutic approaches for TNBC.

scholarly journals Isolation and Establishment of a Highly Proliferative, Cancer Stem Cell-Like, and Naturally Immortalized Triple-Negative Breast Cancer Cell Line, KAIMRC2

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1303
Author(s):  
Rizwan Ali ◽  
Hajar Al Zahrani ◽  
Tlili Barhoumi ◽  
Alshaimaa Alhallaj ◽  
Abdullah Mashhour ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Stem Cell ◽  
Cancer Stem Cell ◽  
Cell Line ◽  
Cancer Cell ◽  
Triple Negative Breast Cancer ◽  
Breast Cancer Cell Line ◽  
Triple Negative ◽  
Cancer Cell Line

In vitro studies of a disease are key to any in vivo investigation in understanding the disease and developing new therapy regimens. Immortalized cancer cell lines are the best and easiest model for studying cancer in vitro. Here, we report the establishment of a naturally immortalized highly tumorigenic and triple-negative breast cancer cell line, KAIMRC2. This cell line is derived from a Saudi Arabian female breast cancer patient with invasive ductal carcinoma. Immunocytochemistry showed a significant ratio of the KAIMRC2 cells’ expressing key breast epithelial and cancer stem cells (CSCs) markers, including CD47, CD133, CD49f, CD44, and ALDH-1A1. Gene and protein expression analysis showed overexpression of ABC transporter and AKT-PI3Kinase as well as JAK/STAT signaling pathways. In contrast, the absence of the tumor suppressor genes p53 and p73 may explain their high proliferative index. The mice model also confirmed the tumorigenic potential of the KAIMRC2 cell line, and drug tolerance studies revealed few very potent candidates. Our results confirmed an aggressive phenotype with metastatic potential and cancer stem cell-like characteristics of the KAIMR2 cell line. Furthermore, we have also presented potent small molecule inhibitors, especially Ryuvidine, that can be further developed, alone or in synergy with other potent inhibitors, to target multiple cancer-related pathways.

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