scholarly journals Achieving clinical success with BET inhibitors as anti-cancer agents

Author(s):  
Tatiana Shorstova ◽  
William D. Foulkes ◽  
Michael Witcher

AbstractThe transcriptional upregulation of oncogenes is a driving force behind the progression of many tumours. However, until a decade ago, the concept of ‘switching off’ these oncogenic pathways represented a formidable challenge. Research has revealed that members of the bromo- and extra-terminal domain (BET) motif family are key activators of oncogenic networks in a spectrum of cancers; their function depends on their recruitment to chromatin through two bromodomains (BD1 and BD2). The advent of potent inhibitors of BET proteins (BETi), which target either one or both bromodomains, represents an important step towards the goal of suppressing oncogenic networks within tumours. Here, we discuss the biology of BET proteins, advances in BETi design and highlight potential biomarkers predicting their activity. We also outline the logic of incorporating BETi into combination therapies to enhance its efficacy. We suggest that understanding mechanisms of activity, defining predictive biomarkers and identifying potent synergies represents a roadmap for clinical success using BETi.

2021 ◽  
Vol 22 (20) ◽  
pp. 11102
Author(s):  
Joanna Sarnik ◽  
Tomasz Popławski ◽  
Paulina Tokarz

Transcriptional dysregulation is a hallmark of cancer and can be an essential driver of cancer initiation and progression. Loss of transcriptional control can cause cancer cells to become dependent on certain regulators of gene expression. Bromodomain and extraterminal domain (BET) proteins are epigenetic readers that regulate the expression of multiple genes involved in carcinogenesis. BET inhibitors (BETis) disrupt BET protein binding to acetylated lysine residues of chromatin and suppress the transcription of various genes, including oncogenic transcription factors. Phase I and II clinical trials demonstrated BETis’ potential as anticancer drugs against solid tumours and haematological malignancies; however, their clinical success was limited as monotherapies. Emerging treatment-associated toxicities, drug resistance and a lack of predictive biomarkers limited BETis’ clinical progress. The preclinical evaluation demonstrated that BETis synergised with different classes of compounds, including DNA repair inhibitors, thus supporting further clinical development of BETis. The combination of BET and PARP inhibitors triggered synthetic lethality in cells with proficient homologous recombination. Mechanistic studies revealed that BETis targeted multiple essential homologous recombination pathway proteins, including RAD51, BRCA1 and CtIP. The exact mechanism of BETis’ anticancer action remains poorly understood; nevertheless, these agents provide a novel approach to epigenome and transcriptome anticancer therapy.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Chen Li ◽  
Yan Wang ◽  
Yueqing Gong ◽  
Tengrui Zhang ◽  
Jiaqi Huang ◽  
...  

AbstractEnhancer of zeste homolog 2 inhibitors (EZH2i) have garnered increased attention owing to their anticancer activity by targeting EZH2, a well-known cancer-promoting factor. However, some lymphomas are resistant to EZH2i, and EZH2i treatment alone is ineffective in case of EZH2-overexpressing solid tumors. The anti-cancer efficacy of EZH2i may be improved through safe and effective combinations of these drugs with other treatment modalities. Preclinical evidence indicates that combining EZH2i with other therapies, such as immunotherapy, chemotherapy, targeted therapy, and endocrine therapy, has complementary or synergistic antitumor effects. Therefore, elucidating the underlying mechanisms of the individual constituents of the combination therapies is fundamental for their clinical application. In this review, we have summarized notable clinical trials and preclinical studies using EZH2i, their progress, and combinations of EZH2i with different therapeutic modalities, aiming to provide new insights for tumor treatment.


2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi31-vi31
Author(s):  
Anna Laemmerer ◽  
Dominik Kirchhofer ◽  
Sibylle Madlener ◽  
Daniela Loetsch-Gojo ◽  
Carola Jaunecker ◽  
...  

Abstract BACKGROUND Central nervous system (CNS) tumors are the second most common childhood cancer. Despite innovations in surgery and chemo-/radiotherapy, CNS tumors remain the major cause of cancer-related death in children. Previous sequencing analyses in a pediatric cancer cohort identified BRCA and DSB repair signatures as potentially targetable events. Based on these findings, we propose the use of PARP inhibitors (PARPi) for aggressive CNS tumor subtypes, including high-grade glioma (HGG), medulloblastoma (MB) and ependymoma (EPN). METHODS We tested multiple PARPi in tumor cell lines (n=8) as well as primary patient-derived models (n=11) of pediatric HGG, MB, EPN and atypical teratoid/rhabdoid tumors (ATRTs). Based on PARPi sensitivity, selected models were further exposed to a combination of PARPi and DNA-damaging/modifying agents. The mode of action was investigated using Western blot and flow cytometry. RESULTS We show that a fraction of pediatric MB, EPN and ATRT demonstrate sensitivity towards PARP inhibition, which is paralleled by susceptibility to the DNA damaging drugs cisplatin and irinotecan. Interestingly, talazoparib, the most potent PARPi, showed synergistic cytotoxicity with DNA-damaging/modifying drugs. In addition, cell cycle blockade and increased DNA damage combined with reduced DNA repair signaling, such as activation of the ATR/Chk1 pathway were observed. Corroboratively, talazoparib exhibited a synergistic anti-cancer effect in combination with inhibitors of ATR, a major regulator of DNA damage response. CONCLUSION/OUTLOOK To sum up, we demonstrate that PARP inhibition synergizes with DNA damaging anti-cancer compounds or DNA repair inhibitors and, thus, represents a promising therapeutic strategy for a defined subgroup of pediatric high-risk CNS tumors patients. More in depth characterization of the underlying molecular events will most likely allow the identification of predictive biomarkers for most efficient implementation of this strategy into clinical application.


2010 ◽  
Vol 46 (5) ◽  
pp. 869-879 ◽  
Author(s):  
Nayef A. Alymani ◽  
Murray D. Smith ◽  
David J. Williams ◽  
Russell D. Petty

2021 ◽  
Vol 35 (S1) ◽  
Author(s):  
Grover Miller ◽  
Mary Schleiff ◽  
Noah Flynn ◽  
Michael Ward ◽  
Coretine Laurin ◽  
...  

2020 ◽  
Vol 3 (2) ◽  
pp. 80-94 ◽  
Author(s):  
AbdelAziz R Jalil ◽  
Jason C Andrechak ◽  
Dennis E Discher

Abstract The macrophage checkpoint is an anti-phagocytic interaction between signal regulatory protein alpha (SIRPα) on a macrophage and CD47 on all types of cells – ranging from blood cells to cancer cells. This interaction has emerged over the last decade as a potential co-target in cancer when combined with other anti-cancer agents, with antibodies against CD47 and SIRPα currently in preclinical and clinical development for a variety of hematological and solid malignancies. Monotherapy with CD47 blockade is ineffective in human clinical trials against many tumor types tested to date, except for rare cutaneous and peripheral lymphomas. In contrast, pre-clinical results show efficacy in multiple syngeneic mouse models of cancer, suggesting that many of these tumor models are more immunogenic and likely artificial compared to human tumors. However, combination therapies in humans of anti-CD47 with agents such as the anti-tumor antibody rituximab do show efficacy against liquid tumors (lymphoma) and are promising. Here, we review such trials as well as key interaction and structural features of CD47-SIRPα.


2020 ◽  
Vol 9 (10) ◽  
pp. 3226
Author(s):  
Cristina Belgiovine ◽  
Elisabeth Digifico ◽  
Clément Anfray ◽  
Aldo Ummarino ◽  
Fernando Torres Andón

In the last decade, it has been well-established that tumor-infiltrating myeloid cells fuel not only the process of carcinogenesis through cancer-related inflammation mechanisms, but also tumor progression, invasion, and metastasis. In particular, tumor-associated macrophages (TAMs) are the most abundant leucocyte subset in many cancers and play a major role in the creation of a protective niche for tumor cells. Their ability to generate an immune-suppressive environment is crucial to escape the immune system and to allow the tumor to proliferate and metastasize to distant sites. Conventional therapies, including chemotherapy and radiotherapy, are often not able to limit cancer growth due to the presence of pro-tumoral TAMs; these are also responsible for the failure of novel immunotherapies based on immune-checkpoint inhibition. Several novel therapeutic strategies have been implemented to deplete TAMs; however, more recent approaches aim to use TAMs themselves as weapons to fight cancer. Exploiting their functional plasticity, the reprogramming of TAMs aims to convert immunosuppressive and pro-tumoral macrophages into immunostimulatory and anti-tumor cytotoxic effector cells. This shift eventually leads to the reconstitution of a reactive immune landscape able to destroy the tumor. In this review, we summarize the current knowledge on strategies able to reprogram TAMs with single as well as combination therapies.


2020 ◽  
Vol 12 (18) ◽  
pp. 1669-1683
Author(s):  
Yifei Yang ◽  
Zhenwei Wu ◽  
Pan Chen ◽  
Peiyuan Zheng ◽  
Huibin Zhang ◽  
...  

Bromodomain and extra-terminal domain (BET) protein family plays an important role in regulating gene transcription preferentially at super-enhancer regions and has been involved with several types of cancers as a candidate. Up to now, there are 16 pan-BET inhibitors in clinical trials, however, most of them have undesirable off-target and side-effects. The proteolysis-targeting chimeras technology through a heterobifunctional molecule to link the target protein and E3 ubiquitin ligase, causes the target’s ubiquitination and subsequent degradation. By using this technology, the heterobifunctional small-molecule BET degraders can induce BET protein degradation. In this review, we discuss the advances in the drug discovery and development of BET-targeting proteolysis-targeting chimeras.


2020 ◽  
Vol 11 ◽  
Author(s):  
Rachel E. Crossland ◽  
Francesca Perutelli ◽  
Katarzyna Bogunia-Kubik ◽  
Nuala Mooney ◽  
Nina Milutin Gašperov ◽  
...  

Prognostic, diagnostic or predictive biomarkers are urgently needed for assessment of chronic graft-versus-host disease (cGvHD), a major risk for patients undergoing allogeneic hematopoietic stem cell transplantation. The main goal of this review generated within the COST Action EUROGRAFT “Integrated European Network on Chronic Graft Versus Host Disease” was to identify potential novel biomarkers for cGvHD besides the widely accepted molecular and cellular biomarkers. Thus, the focus was on cellular biomarkers, alloantibodies, glycomics, endothelial derived particles, extracellular vesicles, microbiome, epigenetic and neurologic changes in cGvHD patients. Both host-reactive antibodies in general, and particularly alloantibodies have been associated with cGvHD and require further consideration. Glycans attached to IgG modulate its activity and represent a promising predictive and/or stratification biomarker for cGVHD. Furthermore, epigenetic changes such as microRNAs and DNA methylation represent potential biomarkers for monitoring cGvHD patients and novel targets for developing new treatment approaches. Finally, the microbiome likely affects the pathophysiology of cGvHD; bacterial strains as well as microbial metabolites could display potential biomarkers for dysbiosis and risk for the development of cGvHD. In summary, although there are no validated biomarkers currently available for clinical use to better inform on the diagnosis, prognosis or prediction of outcome for cGvHD, many novel sources of potential markers have shown promise and warrant further investigation using well characterized, multi-center patient cohorts.


Author(s):  
Jeffrey Graham ◽  
Daniel Y. C. Heng ◽  
James Brugarolas ◽  
Ulka Vaishampayan

The treatment of renal cell carcinoma represents one of the great success stories in translational cancer research, with the development of novel therapies targeting key oncogenic pathways. These include drugs that target the VEGF and mTOR pathways, as well as novel immuno-oncology agents. Despite the therapeutic advancements, there is a paucity of well-validated prognostic and predictive biomarkers in advanced kidney cancer. With a number of highly effective therapies available across multiple lines, it will become increasingly important to develop a more tailored approach to treatment selection. Prognostic clinical models, such the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) model, are routinely used for prognostication in clinical practice. The IMDC model has demonstrated a predictive capability in the context of these treatments including immune checkpoint inhibition. A number of promising molecular markers and gene expression signatures are being explored as prognostic and predictive biomarkers, but none are ready to be widely used for treatment selection. In this review, we will explore the current landscape of personalized care in metastatic renal cell carcinoma. This will include a focus on both prognostic and predictive factors as well as clinical applications of biology in kidney cancer.


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