scholarly journals Inhibition of Histone Demethylases LSD1 and UTX Regulates ERα Signaling in Breast Cancer

Cancers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2027 ◽  
Author(s):  
Rosaria Benedetti ◽  
Carmela Dell’Aversana ◽  
Tommaso De Marchi ◽  
Dante Rotili ◽  
Ning Qing Liu ◽  
...  

In breast cancer, Lysine-specific demethylase-1 (LSD1) and other lysine demethylases (KDMs), such as Lysine-specific demethylase 6A also known as Ubiquitously transcribed tetratricopeptide repeat, X chromosome (UTX), are co-expressed and co-localize with estrogen receptors (ERs), suggesting the potential use of hybrid (epi)molecules to target histone methylation and therefore regulate/redirect hormone receptor signaling. Here, we report on the biological activity of a dual-KDM inhibitor (MC3324), obtained by coupling the chemical properties of tranylcypromine, a known LSD1 inhibitor, with the 2OG competitive moiety developed for JmjC inhibition. MC3324 displays unique features not exhibited by the single moieties and well-characterized mono-pharmacological inhibitors. Inhibiting LSD1 and UTX, MC3324 induces significant growth arrest and apoptosis in hormone-responsive breast cancer model accompanied by a robust increase in H3K4me2 and H3K27me3. MC3324 down-regulates ERα in breast cancer at both transcriptional and non-transcriptional levels, mimicking the action of a selective endocrine receptor disruptor. MC3324 alters the histone methylation of ERα-regulated promoters, thereby affecting the transcription of genes involved in cell surveillance, hormone response, and death. MC3324 reduces cell proliferation in ex vivo breast cancers, as well as in breast models with acquired resistance to endocrine therapies. Similarly, MC3324 displays tumor-selective potential in vivo, in both xenograft mice and chicken embryo models, with no toxicity and good oral efficacy. This epigenetic multi-target approach is effective and may overcome potential mechanism(s) of resistance in breast cancer.

2020 ◽  
Author(s):  
Xiao Tan ◽  
Zhongqiang Zhang ◽  
Ping Liu ◽  
Hongliang Yao ◽  
jingshan tong

Abstract Background: PIK3CA mutations are common genomic alterations in estrogen receptor (ER)-positive breast cancers, currently, the development of selective PI3Kα (phosphatidylinositol 3-kinase α) inhibitors is ongoing. The mechanisms contributing to the anticancer activity of alpelisib in PIK3CA-mutant breast cancer cells and the mechanism of acquired resistance to alpelisib remain elusive. Methods: Drug-sensitive cell lines were exposed to alpelisib to establish alpelisib-resistant cell lines. Western blotting was used to assess changes in protein expression. Apoptosis was evaluated by flow cytometry. In vivo with mouse xenograft models and in vitro colony formation and MTS and assay were carried out to determine the growth inhibitory effects of the tested drugs. Protein half-lives were examined and proteasome inhibitors were used to estimate protein degradation. Gene knockdown was carried out using shRNA or siRNA. Results: In the present study, we report the potent induction of apoptosis by alpelisib in PIK3CA-mutant breast cancer cell lines. AKT phosphorylation suppression, AKT/Foxo3a-dependent Bim induction, and AKT/GSK-3β-dependent Mcl-1 degradation were observed. Apoptosis induced by alpelisib was attenuated by Mcl-1 (4A) overexpression or Bim suppression. Furthermore, alpelisib could not modulate Mcl-1 or Bim levels in cell lines that were resistant to alpelisib. AKT inhibitor and alpelisib combination restored the sensitivity of alpelisib-resistant cells to growth inhibition and apoptosis in vitro and in vivo. Conclusions: Therefore, modulation of Mcl-1 degradation and AKT-dependent Bim induction are crucial for mediating the resistance and sensitivity of PIK3CA-mutant breast tumor cells to alpelisib, thus making it a productive strategy for overcoming acquired resistance to alpelisib.


2019 ◽  
Vol 20 (11) ◽  
pp. 2773 ◽  
Author(s):  
Coralie Poulard ◽  
Julien Jacquemetton ◽  
Olivier Trédan ◽  
Pascale A. Cohen ◽  
Julie Vendrell ◽  
...  

Endocrine therapies targeting oestrogen signalling have significantly improved breast cancer management. However, their efficacy is limited by intrinsic and acquired resistance to treatment, which remains a major challenge for oestrogen receptor α (ERα)-positive tumours. Though many studies using in vitro models of endocrine resistance have identified putative actors of resistance, no consensus has been reached. We demonstrated previously that oestrogen non-genomic signalling, characterized by the formation of the ERα/Src/PI3K complex, is activated in aggressive breast cancers (BC). We wondered herein whether the activation of this pathway is also involved in resistance to endocrine therapies. We studied the interactions between ERα and Src or PI3K by proximity ligation assay (PLA) in in-vitro and in-vivo endocrine therapy-resistant breast cancer models. We reveal an increase in ERα/Src and ERα/PI3K interactions in patient-derived xenografts (PDXs) with acquired resistance to tamoxifen, as well as in tamoxifen-resistant MCF-7 cells compared to parental counterparts. Moreover, no interactions were observed in breast cancer cells resistant to other endocrine therapies. Finally, the use of a peptide inhibiting the ERα–Src interaction partially restored tamoxifen sensitivity in resistant cells, suggesting that such components could constitute promising targets to circumvent resistance to tamoxifen in BC.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yi Bao ◽  
Gokce Oguz ◽  
Wee Chyan Lee ◽  
Puay Leng Lee ◽  
Kakaly Ghosh ◽  
...  

AbstractHER2-targeted therapy has yielded a significant clinical benefit in patients with HER2+ breast cancer, yet disease relapse due to intrinsic or acquired resistance remains a significant challenge in the clinic. Here, we show that the protein phosphatase 2A (PP2A) regulatory subunit PPP2R2B is a crucial determinant of anti-HER2 response. PPP2R2B is downregulated in a substantial subset of HER2+ breast cancers, which correlates with poor clinical outcome and resistance to HER2-targeted therapies. EZH2-mediated histone modification accounts for the PPP2R2B downregulation, resulting in sustained phosphorylation of PP2A targets p70S6K and 4EBP1 which leads to resistance to inhibition by anti-HER2 treatments. Genetic depletion or inhibition of EZH2 by a clinically-available EZH2 inhibitor restores PPP2R2B expression, abolishes the residual phosphorylation of p70S6K and 4EBP1, and resensitizes HER2+ breast cancer cells to anti-HER2 treatments both in vitro and in vivo. Furthermore, the same epigenetic mechanism also contributes to the development of acquired resistance through clonal selection. These findings identify EZH2-dependent PPP2R2B suppression as an epigenetic control of anti-HER2 resistance, potentially providing an opportunity to mitigate anti-HER2 resistance with EZH2 inhibitors.


2019 ◽  
Vol 1 (Supplement_1) ◽  
pp. i7-i7
Author(s):  
Jiaojiao Deng ◽  
Sophia Chernikova ◽  
Wolf-Nicolas Fischer ◽  
Kerry Koller ◽  
Bernd Jandeleit ◽  
...  

Abstract Leptomeningeal metastasis (LM), a spread of cancer to the cerebrospinal fluid and meninges, is universally and rapidly fatal due to poor detection and no effective treatment. Breast cancers account for a majority of LMs from solid tumors, with triple-negative breast cancers (TNBCs) having the highest propensity to metastasize to LM. The treatment of LM is challenged by poor drug penetration into CNS and high neurotoxicity. Therefore, there is an urgent need for new modalities and targeted therapies able to overcome the limitations of current treatment options. Quadriga has discovered a novel, brain-permeant chemotherapeutic agent that is currently in development as a potential treatment for glioblastoma (GBM). The compound is active in suppressing the growth of GBM tumor cell lines implanted into the brain. Radiolabel distribution studies have shown significant tumor accumulation in intracranial brain tumors while sparing the adjacent normal brain tissue. Recently, we have demonstrated dose-dependent in vitro and in vivo anti-tumor activity with various breast cancer cell lines including the human TNBC cell line MDA-MB-231. To evaluate the in vivo antitumor activity of the compound on LM, we used the mouse model of LM based on the internal carotid injection of luciferase-expressing MDA-MB-231-BR3 cells. Once the bioluminescence signal intensity from the metastatic spread reached (0.2 - 0.5) x 106 photons/sec, mice were dosed i.p. twice a week with either 4 or 8 mg/kg for nine weeks. Tumor growth was monitored by bioluminescence. The compound was well tolerated and caused a significant delay in metastatic growth resulting in significant extension of survival. Tumors regressed completely in ~ 28 % of treated animals. Given that current treatments for LM are palliative with only few studies reporting a survival benefit, Quadriga’s new agent could be effective as a therapeutic for both primary and metastatic brain tumors such as LM. REF: https://onlinelibrary.wiley.com/doi/full/10.1002/pro6.43


Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 942
Author(s):  
Mei Qi Kwa ◽  
Rafael Brandao ◽  
Trong H. Phung ◽  
Jianfeng Ge ◽  
Giuseppe Scieri ◽  
...  

MRCKα is a ubiquitously expressed serine/threonine kinase involved in cell contraction and F-actin turnover, which is highly amplified in human breast cancer and part of a gene expression signature for bad prognosis. Nothing is known about the in vivo function of MRCKα. To explore MRCKα function in development and in breast cancer, we generated mice lacking a functional MRCKα gene. Mice were born close to the Mendelian ratio and showed no obvious phenotype including a normal mammary gland formation. Assessing breast cancer development using the transgenic MMTV-PyMT mouse model, loss of MRCKα did not affect tumor onset, tumor growth and metastasis formation. Deleting MRCKα and its related family member MRCKβ in two triple-negative breast cancer cell lines resulted in reduced invasion of MDA-MB-231 cells, but did not affect migration of 4T1 cells. Further genomic analysis of human breast cancers revealed that MRCKα is frequently co-amplified with the oncogenes ARID4B and AKT3 which might contribute to the prognostic value of MRCKα expression. Collectively, these data suggest that MRCKα might be a prognostic marker for breast cancer, but probably of limited functional importance.


2021 ◽  
Vol 108 (Supplement_1) ◽  
Author(s):  
C Zabkiewicz ◽  
L Ye ◽  
R Hargest

Abstract Introduction HER2 over-expression denotes poor prognosis in breast cancers.Bone morphogenetic protein(BMP) signalling is known to interact with EGF signalling, co-regulating breast cancer progression.BMP antagonist Gremlin-1 may influence breast cancer disease progression, but this remains unexplored in HER2 positive breast cancers. Method GREM1 and HER2 expression, and clinical outcomes were examined in clinical cohorts.GREM1 overexpression or pEF control plasmid were transduced into BT474 HER2+breast cancer cells. In vitro function tests using BT474 pEF and BT474GREM1cells include 2D/3D growth, migration, and expression of epithelial to mesenchymal transition(EMT)markers. Signalling cascades were examined in BT474 treated with RhGremlin-1. In vivo, BALB/c nude mice underwent either mammary injection or intra-cardiac injection of BT474pEF or BT474GREM1 cells and disease burden assessed. Result GREM1 expression correlates with HER2 in breast tumours(p=0.03) and is higher in metastatic HER2 positive cancers (p = 0.04). HER2 positive patients with high GREM1 have poor survival(p = 0.0002). BT474GREM1cells have up-regulated markers of EMT compared to control. BT474 RhGremlin-1 treated cells have active AKT pathway signalling, independent of BMP signalling. In vitro,  BT474GREM1cells significantly proliferate and migrate compared to control(p<0.05 and p < 0.001).This is confirmed in vivo,  BT474GREM1 mice grew significantly larger mammary tumours(p<0.05) and had more PETCT metastatic hotspots. Conclusion Gremlin-1 is correlated with poor outcomes in HER2 patients and promotes breast cancer cellular growth, migration and metastasis.Gremlin-1 is a novel area of research with potential as a prognostic biomarker and therapeutic target for personalised, effective, breast cancer outcomes. Take-home message BMP antagonists are gaining interest for their potential in breast cancer prognosis and therapeutics.This novel area of research shows BMP antagonist Gremlin-1 is of importance in HER2 positive breast cancers. DRAGONS DEN


2021 ◽  
Vol 187 (1) ◽  
pp. 145-153
Author(s):  
Conor R. Lanahan ◽  
Bridget N. Kelly ◽  
Michele A. Gadd ◽  
Michelle C. Specht ◽  
Carson L. Brown ◽  
...  

Abstract Purpose Safe breast cancer lumpectomies require microscopically clear margins. Real-time margin assessment options are limited, and 20–40% of lumpectomies have positive margins requiring re-excision. The LUM Imaging System previously showed excellent sensitivity and specificity for tumor detection during lumpectomy surgery. We explored its impact on surgical workflow and performance across patient and tumor types. Methods We performed IRB-approved, prospective, non-randomized studies in breast cancer lumpectomy procedures. The LUM Imaging System uses LUM015, a protease-activated fluorescent imaging agent that identifies residual tumor in the surgical cavity walls. Fluorescent cavity images were collected in real-time and analyzed using system software. Results Cavity and specimen images were obtained in 55 patients injected with LUM015 at 0.5 or 1.0 mg/kg and in 5 patients who did not receive LUM015. All tumor types were distinguished from normal tissue, with mean tumor:normal (T:N) signal ratios of 3.81–5.69. T:N ratios were 4.45 in non-dense and 4.00 in dense breasts (p = 0.59) and 3.52 in premenopausal and 4.59 in postmenopausal women (p = 0.19). Histopathology and tumor receptor testing were not affected by LUM015. Falsely positive readings were more likely when tumor was present < 2 mm from the adjacent specimen margin. LUM015 signal was stable in vivo at least 6.5 h post injection, and ex vivo at least 4 h post excision. Conclusions Intraoperative use of the LUM Imaging System detected all breast cancer subtypes with robust performance independent of menopausal status and breast density. There was no significant impact on histopathology or receptor evaluation.


Author(s):  
Lisa Agnello ◽  
Silvia Tortorella ◽  
Annachiara d’Argenio ◽  
Clarissa Carbone ◽  
Simona Camorani ◽  
...  

Abstract Background Management of triple-negative breast cancer (TNBC) is still challenging because of its aggressive clinical behavior and limited targeted treatment options. Cisplatin represents a promising chemotherapeutic compound in neoadjuvant approaches and in the metastatic setting, but its use is limited by scarce bioavailability, severe systemic side effects and drug resistance. Novel site-directed aptamer-based nanotherapeutics have the potential to overcome obstacles of chemotherapy. In this study we investigated the tumor targeting and the anti-tumorigenic effectiveness of novel cisplatin-loaded and aptamer-decorated nanosystems in TNBC. Methods Nanotechnological procedures were applied to entrap cisplatin at high efficacy into polymeric nanoparticles (PNPs) that were conjugated on their surface with the epidermal growth factor receptor (EGFR) selective and cell-internalizing CL4 aptamer to improve targeted therapy. Internalization into TNBC MDA-MB-231 and BT-549 cells of aptamer-decorated PNPs, loaded with BODIPY505-515, was monitored by confocal microscopy using EGFR-depleted cells as negative control. Tumor targeting and biodistribution was evaluated by fluorescence reflectance imaging upon intravenously injection of Cyanine7-labeled nanovectors in nude mice bearing subcutaneous MDA-MB-231 tumors. Cytotoxicity of cisplatin-loaded PNPs toward TNBC cells was evaluated by MTT assay and the antitumor effect was assessed by tumor growth experiments in vivo and ex vivo analyses. Results We demonstrate specific, high and rapid uptake into EGFR-positive TNBC cells of CL4-conjugated fluorescent PNPs which, when loaded with cisplatin, resulted considerably more cytotoxic than the free drug and nanovectors either unconjugated or conjugated with a scrambled aptamer. Importantly, animal studies showed that the CL4-equipped PNPs achieve significantly higher tumor targeting efficiency and enhanced therapeutic effects, without any signs of systemic toxicity, compared with free cisplatin and untargeted PNPs. Conclusions Our study proposes novel and safe drug-loaded targeted nanosystems for EGFR-positive TNBC with excellent potential for the application in cancer diagnosis and therapy.


Cancers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 5009
Author(s):  
Swetha Vasudevan ◽  
Ibukun A. Adejumobi ◽  
Heba Alkhatib ◽  
Sangita Roy Chowdhury ◽  
Shira Stefansky ◽  
...  

Triple-negative breast cancer (TNBC) is an aggressive subgroup of breast cancers which is treated mainly with chemotherapy and radiotherapy. Epidermal growth factor receptor (EGFR) was considered to be frequently expressed in TNBC, and therefore was suggested as a therapeutic target. However, clinical trials of EGFR inhibitors have failed. In this study, we examine the relationship between the patient-specific TNBC network structures and possible mechanisms of resistance to anti-EGFR therapy. Using an information-theoretical analysis of 747 breast tumors from the TCGA dataset, we resolved individualized protein network structures, namely patient-specific signaling signatures (PaSSS) for each tumor. Each PaSSS was characterized by a set of 1–4 altered protein–protein subnetworks. Thirty-one percent of TNBC PaSSSs were found to harbor EGFR as a part of the network and were predicted to benefit from anti-EGFR therapy as long as it is combined with anti-estrogen receptor (ER) therapy. Using a series of single-cell experiments, followed by in vivo support, we show that drug combinations which are not tailored accurately to each PaSSS may generate evolutionary pressure in malignancies leading to an expansion of the previously undetected or untargeted subpopulations, such as ER+ populations. This corresponds to the PaSSS-based predictions suggesting to incorporate anti-ER drugs in certain anti-TNBC treatments. These findings highlight the need to tailor anti-TNBC targeted therapy to each PaSSS to prevent diverse evolutions of TNBC tumors and drug resistance development.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e15047-e15047
Author(s):  
Surender Kharbanda ◽  
Anees Mohammad ◽  
Sachchidanand Tiwari ◽  
Neha Mehrotra ◽  
Sireesh Appajosyula ◽  
...  

e15047 Background: Triple negative breast cancer (TNBC) accounts for about 10-15% of all breast cancers and differ from other types of invasive breast cancers in that they grow and spread faster. TNBCs have limited treatment options and a worse prognosis. Therapy with anthracyclines considered to be one of the most effective agents in the treatment. Unfortunately, resistance to anthracycline therapy is very common due to drug efflux mediated by overexpression of ABC transporter. Pirarubicin (PIRA), an analogue of doxorubicin (DOX), is approved in Japan, Korea and China and is shown to be less cardiotoxic than DOX. Recent studies suggest that cancer stem cells (CSCs) play an important role in tumorigenesis and biology of TNBC. Targeting CSCs may be a promising, novel strategy for the treatment of this aggressive disease. Recent studies have shown that salinomycin (SAL) preferentially targets the viability of CSCs. Methods: SAL and PIRA were co-encapsulated in polylactic acid (PLA)-based block copolymeric nanoparticles (NPs) to efficiently co-deliver these agents to treat TNBC cells. Results: Generated SAL-PIRA co-encapsulated dual drug-loaded NPs showed an average diameter of 110 ± 7 nm, zeta potential of -12.5 mV and PDI of less than 0.25. Both of these anti-cancer agents showed slow and sustained release profile in non-physiological buffer (PBS, pH 7.4) from these dual drug-encapsulated NPs. Additionally, multiple ratios (PIRA:SAL = 3:1, 1:1, 1:3) were encapsulated to generate diverse dual drug-loaded NPs. The results demonstrate that, in contrast to 1:1 and 3:1, treatment of TNBC cells with 1:3 ratio of PIRA:SAL dual drug-loaded NPs, was associated with significant inhibition of growth in vitro in multiple TNBC cell lines. Interestingly, PIRA:SAL (1:3) was synergistic as compared to either SAL- or PIRA single drug-loaded NPs. The IC50 of PIRA and SAL in single drug-encapsulated NPs is 150 nM and 700 nM respectively in MDA-MB-468. Importantly, the IC50 of PIRA in dual drug-encapsulated NPs dropped down to 30 nM (5-fold). Similar results were obtained in SUM-149 TNBC cell line. Studies are underway to evaluate in vivo biological activity of PIRA:SAL (1:3) on tumor growth in a TNBC xenograft mice model. Conclusions: These results demonstrate that a novel dual drug-loaded NP formulation of PIRA and SAL in a unique ratio of 1:3 represents an approach for successful targeting of CSCs and bulk tumor cells in TNBC and potentially other cancer types.


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