Depletion of procathepsin D gene expression by RNA interference – A potential therapeutic target for breast cancer

Abstract Introduction Brain metastasis (BrM) occurs in 10-30% of patients with advanced breast cancer (BC). BrM is increasing in incidence and confers a poor prognosis. We aimed to investigate the contribution of global epi-transcriptomic alterations in N6-methyladenosine (m6A) RNA-methylation as a therapeutic target in brain metastatic breast cancer. Method In preliminary studies we have demonstrated m6A demethylase – FTO as the main contributor to the progression of ER+ breast cancer. Furthermore an association between FTO and reduced disease-free-survival (n=870, p=0.018) was observed. Here we conducted an epigenetic inhibitor screen using two therapeutic agents, ethyl-ester-meclofenamic acid (MA2) and FB23-2 on matched 2D cell line, 3D organoid cultures and patient-derived xenografts (PDX) explant models of brain metastasis. Result Upon integration of mapped global RNA methylation landscape with matched proteomic analysis, we observed genome-wide RNA hypo-methylation of key pluripotency genes, including SOX2 and KLF4, as key players underlying tumour progression to the brain. Genetic and pharmacological inhibition of FTO in novel ex vivo models of BrM significantly reduced protein expression levels of KLF4 and SOX2. Moreover, pharmacological inhibition of FTO with MA2 and FB23-2, inhibited cell proliferation in endocrine-resistant BC and patient BrM cells. We translate our findings to the clinic by demonstrating the efficacy of anti-FTO therapies in several unique PDX and 3D organoid BrM models. Conclusion Our results reveal epi-transcriptional remodelling events as a key mechanism in BrM. This study establishes an early role for targeting RNA methylation in the management of disease progression and presents FTO as a potential therapeutic target in BrM. Take-home message This study establishes an early role for targeting RNA methylation in the management of disease progression and presents FTO as a potential therapeutic target in brain metastatic breast cancer.

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CBP/β-Catenin/FOXM1 Is a Novel Therapeutic Target in Triple Negative Breast Cancer

Cancers ◽

10.3390/cancers10120525 ◽

2018 ◽

Vol 10 (12) ◽

pp. 525 ◽

Cited By ~ 9

Author(s):

Alexander Ring ◽

Cu Nguyen ◽

Goar Smbatyan ◽

Debu Tripathy ◽

Min Yu ◽

...

Keyword(s):

Breast Cancer ◽

Gene Expression ◽

Drug Resistance ◽

Triple Negative Breast Cancer ◽

Therapeutic Target ◽

Triple Negative ◽

Creb Binding Protein ◽

Novel Therapeutic

Background: Triple negative breast cancers (TNBCs) are an aggressive BC subtype, characterized by high rates of drug resistance and a high proportion of cancer stem cells (CSC). CSCs are thought to be responsible for tumor initiation and drug resistance. cAMP-response element-binding (CREB) binding protein (CREBBP or CBP) has been implicated in CSC biology and may provide a novel therapeutic target in TNBC. Methods: RNA Seq pre- and post treatment with the CBP-binding small molecule ICG-001 was used to characterize CBP-driven gene expression in TNBC cells. In vitro and in vivo TNBC models were used to determine the therapeutic effect of CBP inhibition via ICG-001. Tissue microarrays (TMAs) were used to investigate the potential of CBP and associated proteins as biomarkers in TNBC. Results: The CBP/ß-catenin/FOXM1 transcriptional complex drives gene expression in TNBC and is associated with increased CSC numbers, drug resistance and poor survival outcome. Targeting of CBP/β-catenin/FOXM1 with ICG-001 eliminated CSCs and sensitized TNBC tumors to chemotherapy. Immunohistochemistry of TMAs demonstrated a significant correlation between FOXM1 expression and TNBC subtype. Conclusion: CBP/β-catenin/FOXM1 transcriptional activity plays an important role in TNBC drug resistance and CSC phenotype. CBP/β-catenin/FOXM1 provides a molecular target for precision therapy in triple negative breast cancer and could form a rationale for potential clinical trials.

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The RNA helicase DDX5 promotes alveolar rhabdomyosarcoma growth and survival

10.1101/2020.07.08.194092 ◽

2020 ◽

Author(s):

Alberto Gualtieri ◽

Valerio Licursi ◽

Chiara Mozzetta

Keyword(s):

Gene Expression ◽

Soft Tissue ◽

Soft Tissue Sarcoma ◽

Therapeutic Target ◽

Rna Helicase ◽

Potential Therapeutic Target ◽

Growth And Survival ◽

Dead Box ◽

Pharmacological Targets ◽

Xenograft Models

AbstractRhabdomyosarcoma (RMS) is the most common soft-tissue sarcoma of childhood characterized by the inability to exit the proliferative myoblast-like stage. The alveolar fusion positive subtype (FP-ARMS) is the most aggressive and is mainly caused by the expression of PAX3/7-FOXO1 oncoproteins, which are challenging pharmacological targets. Thus, other therapeutic vulnerabilities resulting from gene expression changes are progressively being recognized. Here, we identified the DEAD box RNA helicase 5 (DDX5) as a potential therapeutic target to inhibit FP-ARMS growth. We show that DDX5 is overexpressed in alveolar RMS cells, demonstrating that its depletion drastically decreases FP-ARMS viability and slows tumor growth in xenograft models. Mechanistically, we provide evidence that DDX5 functions upstream the G9a/AKT survival signalling pathway, by modulating G9a protein stability. Finally, we show that G9a interacts with PAX3-FOXO1 and regulates its activity, thus sustaining FP-ARMS myoblastic state. Together, our findings identify a novel survival-promoting loop in FP-ARMS and highlight DDX5 as potential therapeutic target to arrest rhabdomyosarcoma growth.

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