A series of dimeric compounds based on the AVPI motif of Smac were designed and prepared as antagonists of the inhibitor of apoptosis proteins (IAPs). Optimization of cellular potency, physical ...properties, and pharmacokinetic parameters led to the identification of compound 14 (AZD5582), which binds potently to the BIR3 domains of cIAP1, cIAP2, and XIAP (IC50 = 15, 21, and 15 nM, respectively). This compound causes cIAP1 degradation and induces apoptosis in the MDA-MB-231 breast cancer cell line at subnanomolar concentrations in vitro. When administered intravenously to MDA-MB-231 xenograft-bearing mice, 14 results in cIAP1 degradation and caspase-3 cleavage within tumor cells and causes substantial tumor regressions following two weekly doses of 3.0 mg/kg. Antiproliferative effects are observed with 14 in only a small subset of the over 200 cancer cell lines examined, consistent with other published IAP inhibitors. As a result of its in vitro and in vivo profile, 14 was nominated as a candidate for clinical development.
BRD4 is a transcriptional co-activator functioning to recruit regulatory complexes to acetylated chromatin. A subset of High-grade Serous Ovarian Cancer (HGSOC) patients are typified by focal, ...recurrent BRD4 gene amplifications. Despite previously described cancer dependencies, it is unclear whether BRD4 amplification events are oncogenic in HGSOC. We find that physiologically relevant levels of expression of BRD4 isoforms in non-transformed ovarian cells result in cellular transformation. Transcriptional profiling of BRD4-transformed ovarian cells, and BRD4-amplified HGSOC patient samples revealed shared expression patterns, including enriched MYC, and E2F1 gene signatures. Furthermore, we demonstrate that a novel BET inhibitor, AZD5153, is highly active in BRD4-amplified patient derived xenografts and uncover Neuregulin-1 as a novel BRD4 effector. Experiments involving Neuregulin-1 inhibition and exogenous addition, demonstrate Neuregulin-1 as necessary and sufficient for BRD4-mediated transformation. This study demonstrates the oncogenic potential of BRD4 amplification in cancer and establishes BRD4-amplified HGSOC as a potential patient population that could benefit from BET inhibitors.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Structure–activity relationship analysis identified (+)-N-(3-aminopropyl)-N-1-(5-benzyl-3-methyl-4-oxo-1,2thiazolo5,4-dpyrimidin-6-yl)-2-methylpropyl-4-methylbenzamide (AZD4877), from a series of ...novel kinesin spindle protein (KSP) inhibitors, as exhibiting both excellent biochemical potency and pharmaceutical properties suitable for clinical development. The selected compound arrested cells in mitosis leading to the formation of the monopolar spindle phenotype characteristic of KSP inhibition and induction of cellular death. A favorable pharmacokinetic profile and notable in vivo efficacy supported the selection of this compound as a clinical candidate for the treatment of cancer.
Abstract
Relapsed/refractory DLBCL is an aggressive B-cell malignancy with limited treatment options. BTK inhibitors have demonstrated preclinical and clinical activity in DLBCL of the activated ...B-cell (ABC) subset, but responses are limited and not durable. Therefore, an acalabrutinib (BTK inhibitor) combination screen was conducted in a panel of 9 DLBCL cell lines to identify synergistic and active combinations. The in vitro combination of acalabrutinib plus capivasertib (AKT inhibitor) demonstrated significant combination benefit in the ABC-DLBCL cell lines TMD8 (Loewe synergy score 9.3) and OCI-LY10 (Loewe synergy score 3.2). Capivasertib and acalabrutinib monotherapy gave 0% and 85% tumor growth inhibition (TGI) in TMD8 and 5% and 79% in OCI-LY10 tumour xenograft models respectively. The combination gave tumour regressions of 99% in TMD8 and 72% in OCI-LY10. To explore a potential mechanism of action, RNAseq analysis was performed on the TMD8 cell line and TMD8 xenograft tumors treated with the monotherapies and combination. 24-hour monotherapy treatment of TMD8 cells with acalabrutinib altered the expression of 7390 genes while capivasertib altered 398 genes (absolute fold change ≥ 1.25 and adjusted p-value < 0.05), with enrichment for genes regulated by NFkB signalling detected. Pathway analysis following combination treatment revealed significant decrease in expression of the G2M checkpoint pathway genes compared to acalabrutinib alone (Adjusted p-value = 0.007) as well as decreased expression of CDK1, AURKA and MYC, and significant shifts in the TNFa signalling via NFkB pathway (Adjusted p-value = 0.02). The NFkB signalling node was examined in more detail in TMD8 tumor samples treated with the combination. Lower expression of NFKBIA, NFKBID, EGR2 and BCL2A1 was evident in the combination group, compared to control tumors (p<0.01 for all). Interestingly, the combination strongly increased the expression of MS4A2 (CD20) compared to control (Adjusted p-value = 0.002), capivasertib monotherapy (Adjusted p-value = 0.004) and acalabrutinib monotherapy (Adjusted p-value = 0.02). Therefore, we tested the addition of Rituxan to acalabrutinib + capivasertib combination in the TMD8 xenograft model. The triple combination produced durable complete regressions in 5/5 mice after cessation of treatment whereas tumors regrew after cessation of treatment of the acalabrutinib + capivasertib doublet. These data suggest that the combination of BTK and AKT inhibition may enhance anti-tumor activity in ABC DLBCL, with the addition of anti-CD20 giving more durable tumour control.
Citation Format: Kathleen Burke, Justine Roderick-Richardson, Natasha Narang, Brandon Willis, Hannah Dry, Lillian Castriotta, Alan Rosen, Jay Mettetal, Simon Barry, Andrew Bloecher. Combination activity of acalabrutinib and capivasertib in diffuse large B-cell lymphoma abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1024.
Background and Purpose
Savolitinib (AZD6094, HMPL‐504, volitinib) is an oral, potent, and highly MET receptor TK inhibitor. This series of studies aimed to develop a pharmacokinetic–pharmacodynamic ...(PK/PD) model to link inhibition of MET phosphorylation (pMET) by savolitinib with anti‐tumour activity.
Experimental Approach
Cell line‐derived xenograft (CDX) experiments using human lung cancer (EBC‐1) and gastric cancer (MKN‐45) cells were conducted in athymic nude mice using a variety of doses and schedules of savolitinib. Tumour pMET changes and growth inhibition were calculated after 28 days. Population PK/PD techniques were used to construct a PK/PD model for savolitinib.
Key Results
Savolitinib showed dose‐ and dose frequency‐dependent anti‐tumour activity in the CDX models, with more frequent, lower dosing schedules (e.g., twice daily) being more effective than intermittent, higher dosing schedules (e.g., 4 days on/3 days off or 2 days on/5 days off). There was a clear exposure–response relationship, with maximal suppression of pMET of >90%. Data from additional CDX and patient‐derived xenograft (PDX) models overlapped, allowing calculation of a single EC50 of 0.38 ng·ml−1. Tumour growth modelling demonstrated that prolonged, high levels of pMET inhibition (>90%) were required for tumour stasis and regression in the models.
Conclusion and Implications
High and persistent levels of MET inhibition by savolitinib were needed for optimal monotherapy anti‐tumour activity in preclinical models. The modelling framework developed here can be used to translate tumour growth inhibition from the mouse to human and thus guide choice of clinical dose and schedule.
Loss of PTEN protein results in upregulation of the PI3K/AKT pathway, which appears dependent on the PI3Kβ isoform. Inhibitors of PI3Kβ have potential to reduce growth of tumors in which loss of PTEN ...drives tumor progression. We have developed a small-molecule inhibitor of PI3Kβ and PI3Kδ (AZD8186) and assessed its antitumor activity across a panel of cell lines. We have then explored the antitumor effects as single agent and in combination with docetaxel in triple-negative breast (TNBC) and prostate cancer models. In vitro, AZD8186 inhibited growth of a range of cell lines. Sensitivity was associated with inhibition of the AKT pathway. Cells sensitive to AZD8186 (GI50 < 1 μmol/L) are enriched for, but not exclusively associated with, PTEN deficiency. In vivo, AZD8186 inhibits PI3K pathway biomarkers in prostate and TNBC tumors. Scheduling treatment with AZD8186 shows antitumor activity required only intermittent exposure, and that increased tumor control is achieved when AZD8186 is used in combination with docetaxel. AZD8186 is a potent inhibitor of PI3Kβ with activity against PI3Kδ signaling, and has potential to reduce growth of tumors dependent on dysregulated PTEN for growth. Moreover, AZD8186 can be combined with docetaxel, a chemotherapy commonly used to treat advanced TBNC and prostate tumors. The ability to schedule AZD8186 and maintain efficacy offers opportunity to combine AZD8186 more effectively with other drugs.
We report here a novel series of benzimidazole sulfonamides that act as antagonists of the S1P1 receptor, identified by exploiting an understanding of the pharmacophore of a high throughput screening ...(HTS)-derived series of compounds described previously. Lead compound 2 potently inhibits S1P-induced receptor internalization in a cell-based assay (EC50 = 0.05 μM), but has poor physical properties and metabolic stability. Evolution of this compound through structure–activity relationship development and property optimization led to in vivo probes such as 4. However, this compound was unexpectedly found to be a potent CYP3A inducer in human hepatocytes, and thus further chemistry efforts were directed at addressing this liability. By employing a pregnane X receptor (PXR) reporter gene assay to prioritize compounds for further testing in human hepatocytes, we identified lipophilicity as a key molecular property influencing the likelihood of P450 induction. Ultimately, we have identified compounds such as 46 and 47, which demonstrate the desired S1P1 antagonist activity while having greatly reduced risk of CYP3A induction in humans. These compounds have excellent oral bioavailability in preclinical species and exhibit pharmacodynamic effects of S1P1 antagonism in several in vivo models following oral dosing. Relatively modest antitumor activity was observed in multiple xenograft models, however, suggesting that selective S1P1 antagonists would have limited utility as anticancer therapeutics as single agents.
Lung cancer is the most common cause of cancer death globally with a significant, unmet need for more efficacious treatments. The receptor tyrosine kinase MET has been implicated as an oncogene in ...numerous cancer subtypes, including non-small cell lung cancer (NSCLC). Here we explore the therapeutic potential of savolitinib (volitinib, AZD6094, HMPL-504), a potent and selective MET inhibitor, in NSCLC. In vitro, savolitinib inhibits MET phosphorylation with nanomolar potency, which correlates with blockade of PI3K/AKT and MAPK signaling as well as MYC down-regulation. In vivo, savolitinib causes inhibition of these pathways and significantly decreases growth of MET-dependent xenografts. To understand resistance mechanisms, we generated savolitinib resistance in MET-amplified NSCLC cell lines and analyzed individual clones. We found that upregulation of MYC and constitutive mTOR pathway activation is a conserved feature of resistant clones that can be overcome by knockdown of MYC or dual mTORC1/2 inhibition. Lastly, we demonstrate that mechanisms of resistance are heterogeneous, arising via a switch to EGFR dependence or by a requirement for PIM signaling. This work demonstrates the efficacy of savolitinib in NSCLC and characterizes acquired resistance, identifying both known and novel mechanisms that may inform combination strategies in the clinic.
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