Programmed Anuclear Cell Death Delimits Platelet Life Span

Mason, Kylie D.; Carpinelli, Marina R.; Fletcher, Jamie I.; Collinge, J; Hilton, Adrienne; Ellis, Sarah; Kelly, Priscilla N.; Ekert, Paul G.; Metcalf, Donald; Roberts, Andrew W.; Huang, David C.S.; Kile, Benjamin T.

doi:10.1016/j.cell.2007.01.037

Cited by 928 publications

(991 citation statements)

References 45 publications

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“…27,28 However, a dose-limiting thrombocytopenia is observed owing to inhibition of BCL-X L , the primary survival factor for platelet viability. 33 This has resulted in the synthesis of ABT-199, a BCL-2-specific inhibitor, which appears to act in vivo to specifically inhibit BCL-2 without affecting BCL-X L , and thus platelets are spared. 10 However, the survival of only a minority of tumours is dependent on a single anti-apoptotic BCL-2 family member, whereas most tumours are addicted to at least two anti-apoptotic BCL-2 proteins.…”

Section: Discussionmentioning

confidence: 99%

Evaluation and critical assessment of putative MCL-1 inhibitors

et al. 2013

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High levels of BCL-2 family proteins are implicated in a failed/ineffective apoptotic programme, often resulting in diseases, including cancer. Owing to their potential as drug targets in cancer therapy, several inhibitors of BCL-2 family proteins have been developed. These primarily target specific members of the BCL-2 family, particularly BCL-2 and BCL-X L but are ineffective against MCL-1. Major efforts have been invested in developing inhibitors of MCL-1, which is commonly amplified in human tumours and associated with tumour relapse and chemoresistance. In this report, the specificity of several BCL-2 family inhibitors (ABT-263, UCB-1350883, apogossypol and BH3I-1) was investigated and compared with putative MCL-1 inhibitors designed to exhibit improved or selective binding affinities for MCL-1 (TW-37, BI97C1, BI97C10, BI112D1, compounds 6 and 7, and MCL-1 inhibitor molecule (MIM-1)). ABT-263, BI97C1, BI112D1, MIM-1 and TW-37 exhibited specificity in inducing apoptosis in a Bax/Bak-and caspase-9-dependent manner, whereas the other agents showed no killing activity, or little or no specificity. Of these inhibitors, only ABT-263 and UCB-1350883 induced apoptosis in a BCL-2-or BCL-X L -dependent system. In cells that depend on MCL-1 for survival, ABT-263 and TW-37 induced extensive apoptosis, suggesting that at high concentrations these inhibitors have the propensity to inhibit MCL-1 in a cellular context. TW-37 induced apoptosis, assessed by chromatin condensation, caspase processing and phosphatidylserine externalisation, in a BAK-dependent manner and in cells that require MCL-1 for survival. TW-37-mediated apoptosis was also partly dependent on NOXA, suggesting that derivatives of TW-37, if engineered to exhibit better selectivity and efficacy at low nanomolar concentrations, may provide useful lead compounds for further synthetic programmes. Expanded medicinal chemistry iteration, as performed for the ABT series, may likewise improve the potency and specificity of the evaluated MCL-1 inhibitors.

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Section: Discussionmentioning

confidence: 99%

Evaluation and critical assessment of putative MCL-1 inhibitors

et al. 2013

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“…168,169 This problem can be circumvented in the context of BCL-2-dependent tumours by using ABT-199/venetoclax, a BH3-mimetic that only inhibits BCL-2 and is showing great promise for the treatment of CLL. 170 Moreover, to prevent unacceptable collateral damage to normal tissues, BH3-mimetics may best be used in combination therapies with drugs that only affect cancer cells, such as inhibitors of oncogenic kinases (e.g., Gleevec to inhibit BCR-ABL in CML, Vemurafenib to inhibit mutant BRAF in melanoma), rather than using them with cytotoxic drugs that cause DNA damage in both malignant as well as non-transformed cells.…”

Section: The Role Of the Bcl-2-regulated Apoptotic Pathway In Cancer mentioning

confidence: 99%

The BCL-2 protein family, BH3-mimetics and cancer therapy

2015

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Escape from apoptosis is a key attribute of tumour cells and facilitates chemo-resistance. The 'BCL-2-regulated' or 'intrinsic' apoptotic pathway integrates stress and survival signalling to govern whether a cancer cell will live or die. Indeed, many pro-apoptotic members of the BCL-2 family have demonstrated tumour-suppression activity in mouse models of cancer and are lost or repressed in certain human cancers. Conversely, overexpression of pro-survival BCL-2 family members promotes tumorigenesis in humans and in mouse models. Many of the drugs currently used in the clinic mediate their therapeutic effects (at least in part) through the activation of the BCL-2-regulated apoptotic pathway. However, initiators of this apoptotic pathway, such as p53, are mutated, lost or silenced in many human cancers rendering them refractory to treatment. To counter such resistance mechanisms, a novel class of therapeutics, 'BH3-mimetics', has been developed. These drugs directly activate apoptosis by binding and inhibiting select antiapoptotic BCL-2 family members and thereby bypass the requirement for upstream initiators, such as p53. In this review, we discuss the role of the BCL-2 protein family in the development and treatment of cancer, with an emphasis on mechanistic studies using well-established mouse models of cancer, before describing the development and already recognised potential of the BH3-mimetic compounds.

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“…5 The generation of chimaeric or tissue-specific Bcl-X −/− revealed a critical role for BCL-XL in the survival of developing lymphocytes 5 and platelets. 6,7 Mcl-1 −/− embryos die before implantation (E3.5), 8 but conditional Mcl-1 deletion models have demonstrated an essential role for MCL-1 in the survival of haematopoietic stem cells, lymphocytes, neurons and cardiomyocytes. [9][10][11][12][13][14][15] Bcl-W −/− mice have impaired spermatogenesis.…”

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confidence: 99%

Characterisation of mice lacking all functional isoforms of the pro-survival BCL-2 family member A1 reveals minor defects in the haematopoietic compartment

et al. 2017

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The pro-survival proteins of the BCL-2 family regulate the survival of all cells, and genetic deletion models for these proteins have revealed which specific BCL-2 family member(s) is/are critical for the survival of particular cell types. A1 is a pro-survival BCL-2-like protein that is expressed predominantly in haematopoietic cells, and here we describe the characterisation of a novel mouse strain that lacks all three functional isoforms of A1 (A1-a, A1-b and A1-d). Surprisingly, complete loss of A1 caused only minor defects, with significant, although relatively small, decreases in γδTCR T cells, antigen-experienced conventional as well as regulatory CD4 T cells and conventional dendritic cells (cDCs). When examining these cell types in tissue culture, only cDC survival was significantly impaired by the loss of A1. Therefore, A1 appears to be a surprisingly redundant pro-survival protein in the haematopoietic system and other tissues, suggesting that its targeting in cancer may be readily tolerated. Cell Death and Differentiation (2017) 24, 534-545; doi:10.1038/cdd.2016.156; published online 13 Janaury 2017The pro-survival proteins of the BCL-2 family prevent apoptosis 1 and studies using gene-targeted mice have revealed which cell types rely on which pro-survival protein for their survival. For example, Bcl-2 −/− mice exhibit thymic and splenic atrophy, a loss of fur pigment and die~30 days post birth from polycystic kidney disease, attributable to excess lymphocyte, melanocyte and renal epithelial cell apoptosis, respectively. 2-4 Bcl-X −/− mice die before E14.5 of embryonic development because of aberrant death of erythroid and neuronal cells. 5 The generation of chimaeric or tissue-specific Bcl-X −/− revealed a critical role for BCL-XL in the survival of developing lymphocytes 5 and platelets. 6,7 Mcl-1 −/− embryos die before implantation (E3.5), 8 but conditional Mcl-1 deletion models have demonstrated an essential role for MCL-1 in the survival of haematopoietic stem cells, lymphocytes, neurons and cardiomyocytes. 9-15 Bcl-W −/− mice have impaired spermatogenesis. 16,17 A1 remains the only pro-survival BCL-2 family member for which a knockout mouse strain has not been developed. A1 was first discovered as a GM-CSF-inducible gene with significant sequence similarity to BCL-2 and MCL-1, 18 and its human homologue BFL-1 was later identified in fetal liver. 19 Overexpression of A1 protected an IL-3-dependent cell line from growth factor deprivation-induced apoptosis, thus demonstrating its pro-survival function. 20 In mice, A1 expression is restricted to the haematopoietic compartment. 18 Human BFL-1 expression is more widespread, but also predominantly haematopoietic. 21 A1 can be upregulated by NF-κB signalling, and it has been proposed that A1/BFL-1 is important for the survival of several activated immune cell subsets through stimulation of antigen or cytokine receptors. [22][23][24][25] Studies of A1 in mice are complicated by the presence of multiple isoforms that are the result of gene duplication ev...

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Programmed Anuclear Cell Death Delimits Platelet Life Span

Cited by 928 publications

References 45 publications

Evaluation and critical assessment of putative MCL-1 inhibitors

Evaluation and critical assessment of putative MCL-1 inhibitors

The BCL-2 protein family, BH3-mimetics and cancer therapy

Characterisation of mice lacking all functional isoforms of the pro-survival BCL-2 family member A1 reveals minor defects in the haematopoietic compartment

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