ABSTRACT As many oncogenic changes, such as Myc overexpression, promote apoptosis, the survival of emerging neoplastic clones may often initially depend upon endogenous levels of particular

pro-survival members of the Bcl-2 protein family. Pertinently, we recently showed that in lymphoma-prone E_μ_-_myc_ transgenic mice, which overexpress Myc in all B-lymphoid cells, endogenous

Bcl-xL is critical for the survival, as well as the expansion of preneoplastic B-lymphoid cells and the development of malignant disease. This discovery raised the possibility that

pharmacological blockade of Bcl-xL might impede Myc-driven lymphoma development. Indeed, we report here that treatment of preleukaemic E_μ-myc_ transgenic mice with the Bcl-2 homology (BH)3

expression. Moreover, such treatment may help in the management of patients with hereditary cancer syndromes and perhaps also in the prevention of tumour relapses. SIMILAR CONTENT BEING

VIEWED BY OTHERS BCL-W MAKES ONLY MINOR CONTRIBUTIONS TO MYC-DRIVEN LYMPHOMA DEVELOPMENT Article Open access 11 August 2023 TRIB3 PROMOTES MYC-ASSOCIATED LYMPHOMA DEVELOPMENT THROUGH

SUPPRESSION OF UBE3B-MEDIATED MYC DEGRADATION Article Open access 09 December 2020 MNT SUPPRESSES T CELL APOPTOSIS VIA BIM AND IS CRITICAL FOR T LYMPHOMAGENESIS Article Open access 08

February 2023 MAIN Evasion of apoptosis is a prerequisite for the development of most, possibly all, malignancies.1, 2, 3 Apoptosis is controlled largely by opposing factions of the Bcl-2

family.4, 5 The members promoting cell survival include Bcl-2, Bcl-xL, Bcl-w, Mcl-1 and A1, which all have four Bcl-2 homology (BH) domains. Largely owing to their diverse expression

patterns, particular pro-survival Bcl-2 family members are critical to sustain survival of specific cell types.6 One pro-apoptotic faction includes Bax and Bak, which also bear four BH

domains and share extensive structural similarity with their pro-survival relatives,6 and their activation is essential for the pivotal step of mitochondrial outer membrane permeabilisation,

which unleashes the caspase cascade that demolishes the cell.4, 7 The members of the more distantly related second pro-apoptotic group, the so-called BH3-only proteins (e.g. Bim, Puma,

Bad), share with each other and the wider Bcl-2 family only the BH3 domain. The BH3-only proteins, which are activated by diverse stress stimuli, including cytokine deprivation and DNA

damage, are essential to initiate apoptosis signalling. They are thought to activate Bax and Bak either by binding them directly (e.g. in the case of Bim, tBid and Puma) or by liberating

them from guardian pro-survival Bcl-2 relatives or both ways.4, 5, 8 As recently reviewed,5 both genetic alterations in human tumours and analysis of transgenic mice overexpressing Bcl-2 or

a pro-survival homologue leave no doubt that these proteins can contribute to neoplastic transformation. However, on its own, the tumorigenic impact of Bcl-2 is relatively low,9, 10 unless

another oncogene, such as Myc, is coexpressed.11 As many of the mutations that initiate oncogenesis, like those imposing Myc overexpression, disturb cell cycle checkpoints and thereby render

cells more sensitive to apoptosis,12 we reasoned that emerging neoplastic clones could be particularly dependent upon the endogenous levels of certain Bcl-2 pro-survival proteins. We

examined this hypothesis using the well-studied lymphoma-prone E_μ_-_myc_ transgenic mice, in which enforced Myc expression creates an expanded pool of proliferating (preleukaemic) pro-B and

pre-B lymphocytes from which malignant clones emerge.13, 14, 15 To test the consequences of loss of Bcl-2 or Bcl-xL in these mice, we circumvented the early postnatal or embryonic lethality

provoked, respectively, by loss of Bcl-216, 17 or Bcl-xL18 by generating cohorts of chimaeric mice in which the haemopoietic system had an E_μ-myc_/_bcl-2_−/−, E_μ-myc_/_bcl-x_−/− or

control genotype.19, 20 Bcl-2 and Bcl-xL both proved critical for the survival of preleukaemic E_μ-myc_ mature (sIg+) B cells, but only Bcl-xL was required for the survival and accumulation

of preleukaemic E_μ-myc_ pro-B and pre-B cells. Remarkably, whereas loss of Bcl-2 affected neither the incidence nor rate of lymphoma development,19 loss of Bcl-xL abrogated the

lymphomagenesis.20 These observations are consistent with the notion that the pro-B and pre-B cell stages are critical for neoplastic progression in this mouse lymphoma model, most likely

due to their high rate of proliferation and the genomic instability caused by immunoglobulin gene rearrangement, which both facilitate acquisition of mutations.21 Our demonstration that

Bcl-xL was essential for the survival of Myc-driven lymphoma-initiating cells while they acquire the additional oncogenic lesions that propel neoplastic transformation raised the possibility

that pharmacological blockade of Bcl-xL might, similar to loss of the _bcl-x_ gene,20 inhibit Myc-induced lymphomagenesis. BH3 mimetics, synthetic compounds that mimic the BH3-only proteins

by engaging and inhibiting one or more of the pro-survival proteins, are showing great promise for cancer therapy,5, 22, 23 particularly in chronic lymphocytic leukaemia,24 but their

potential for preventing cancer has not yet been explored. Here we demonstrate that prophylactic treatment of preleukaemic E_μ-myc_ mice with the BH3 mimetic ABT-737, which neutralises

Bcl-xL, Bcl-2 and Bcl-w but not Mcl-1 or A1,22, 25 markedly delayed the onset and greatly reduced the incidence of lymphoma development. RESULTS To generate standardised cohorts of

lymphoma-prone and control animals, the haemopoietic system of lethally irradiated C57BL/6-Ly5.1 mice was reconstituted with haemopoietic stem/progenitor cells derived from the fetal liver

of E14.5 E_μ-myc_ mice. Six weeks post reconstitution, the recipients (hereafter called E_μ-myc_ mice) were treated with either a single dose of ABT-737 (75 mg/kg body weight)22 or for 2

weeks with three doses per week to monitor short-term effects on the preleukaemic B-lymphoid compartment (Figure 1). Alternatively, mice were treated for an 8-week period (three doses per

week) to assess long-term effects on lymphomagenesis (Figure 1). ABT-737 REDUCES THE NUMBERS OF PRELEUKAEMIC B-LYMPHOID CELLS IN E _Μ_ _-MYC_ MICE The enforced Myc expression in E_μ-myc_

mice generates a several-fold elevation in preleukaemic pro-B and pre-B cell numbers in haemopoietic tissues,15 but the elevated Myc also renders these lymphocytes more susceptible to

apoptotic stimuli, such as growth factor deprivation.26 To assess whether ABT-737 affected the preleukaemic abnormalities caused by Myc overexpression, the reconstituted mice were injected

six times with either ABT-737 (75 mg/kg) or vehicle over a 2-week period (three doses per week) and their content of preleukaemic B-lymphoid cells was determined by flow cytometric analysis.

Remarkably, Figure 2 shows that all B-lymphoid subsets in the ABT-737-treatment cohort were significantly decreased, compared with the vehicle-treated animals, in both the bone marrow

(*_P_pro-B <0.05, ***_P_pre-B <0.001, **_P_sIg+-B <0.01) and the spleen (*_P_pro-B <0.05, *_P_pre-B <0.05, *_P_sIg+-B <0.05). The drop in preleukaemic B-lymphoid cells

elicited by ABT-737 almost certainly reflects increased apoptosis, because TUNEL staining for DNA breaks, a hallmark of apoptosis, revealed that E_μ-myc_ animals treated with a single dose

of ABT-737 contained significantly (**_P_<0.01) more apoptotic cells in their bone marrow than vehicle-treated mice (Figure 3). Collectively, these results demonstrate that ABT-737

treatment causes a significant reduction in the preleukaemic Myc overexpressing B-lymphoid cells within the whole animal by increasing their propensity to undergo apoptosis. ABT-737

SUBSTANTIALLY DELAYS THE ONSET AND REDUCES THE INCIDENCE OF MYC-DRIVEN LYMPHOMA Next, we investigated whether the reduction in preleukaemic B-lymphoid cells and their increased rate of

apoptosis elicited by ABT-737 treatment translated into a delay in Myc-induced lymphomagenesis. Six weeks post reconstitution, cohorts of transgenic mice were treated three times a week for

8 consecutive weeks with ABT-737 (75 mg/kg) or vehicle (Figure 1) and were then monitored for up to 18 months to determine the impact of the drug on the incidence and rate of lymphoma

development. The vehicle-treated E_μ-myc_ mice developed lymphoma as early as 9 weeks post reconstitution and reached a tumour incidence of ∼80% by 60 weeks (Figure 4). In striking contrast,

all 15 ABT-737-treated E_μ-myc_ mice remained tumour-free until 24 weeks post reconstitution and only 2 of them (13.4%) succumbed to lymphoma by 60 weeks (***_P_<0.001; Figure 4).

Notably, the only two lymphomas that arose in the drug-treated arm developed 8 and 40 weeks after cessation of ABT-737 treatment (Figure 4), and therefore both almost certainly developed in

the complete absence of the drug. Furthermore, in these two lymphomas the expression of Bcl-2 family members and sensitivity in culture to apoptotic stimuli closely resembled that of

conventional E_μ-myc_ lymphomas (Figure 5). Hence, these lymphomas most likely represent tumours that were initiated after ABT-737 blockade had ceased. DISCUSSION The now widely accepted

concept that cells must evade apoptosis to become malignant1, 2, 3, 5 was engendered by the discoveries that _bcl-2_, commonly translocated in human follicular lymphoma, promotes cell

survival27 and that its overexpression in transgenic mice promotes lymphomagenesis.9, 10, 11, 28 However, compared with the tumorigenesis driven by enforced expression of the Myc

transgene,14 overexpression of Bcl-2 alone causes only a low incidence of tumours with long latency.9, 10, 11, 28 Hence, we surmise that the initial mutations leading to most cancers enhance

proliferation or self-renewal, and those impairing apoptosis are selected later, for example, to counter the stress imposed by disrupted cell cycle checkpoints. If so, the emerging

neoplastic clones must initially be sustained by endogenous levels of expression of Bcl-2 pro-survival proteins. Accordingly, Bcl-xL proved to be essential for the emergence of E_μ-myc_

lymphomas.20 That discovery prompted us to test whether a BH3 mimetic that can neutralise Bcl-xL could retard tumorigenesis, and indeed, we show here that treatment with ABT-73722 provided

effective prophylaxis against Myc-induced lymphomagenesis. We believe that its prophylactic effect can be ascribed largely (possibly solely) to its ability to antagonise Bcl-xL and not its

other targets, Bcl-2 and Bcl-w.22 Bcl-w is probably not important in this setting because it is only poorly expressed in both normal lymphocytes29 and in Myc-overexpressing preleukaemic

pro-B and pre-B lymphoid cells,30 the cell types from which the E_μ-myc_ lymphomas are thought to arise.13, 14, 15 Bcl-2 is ruled out as a significant target, because its complete loss did

not lower the numbers of the pro-B and pre-B cells in preleukaemic E_μ-myc_ mice and did not notably impact the onset or incidence of E_μ_-_myc_ lymphoma.19 In contrast, both loss of

Bcl-xL20 and ABT-737 prophylaxis reduced the numbers of E_μ-myc_ pre-B cells, rendered them sensitive to apoptosis and potently inhibited Myc-induced lymphomagenesis. Notably, the only two

mice treated prophylactically with ABT-737 that developed lymphoma presented 8 and 40 weeks after ABT-737 treatment had ceased (Figure 4). As the drug has a half-life _in vivo_ of only about

18 h, these tumours clearly arose from Myc-driven preleukaemic precursors that acquired cooperating oncogenic lesions long after ABT-737 was gone. In other words, these two lymphomas most

likely arose _de novo_ from preneoplastic Myc-driven lymphoid cells rather than from transformed lymphoid cells that became resistant to ABT-737. Consistent with this hypothesis, neither of

these two lymphomas displayed any overt abnormalities in the expression of pro-survival or pro-apoptotic Bcl-2 family members or behaviour in culture that might be expected if they had

undergone neoplastic progression under selective pressure exerted by ABT-737, such as marked elevation in Mcl-125 or resistance to apoptosis. These observations indicate that several shorter

intervals of ABT-737 prophylaxis might inhibit E_μ-myc_-induced lymphoma development even more efficiently than the single-period treatment strategy that we employed. Overexpression of Myc

increases expression of the pro-apoptotic BH3-only Bcl-2 family members Bim and Puma,30, 31 and loss of Bim or Puma markedly accelerates E_μ-myc_-induced lymphomagenesis.30, 31, 32, 33, 34

Hence, in the preleukaemic pro-B and pre-B cells of E_μ-myc_ mice treated with ABT-737, we surmise that the elevated levels of Bim and Puma elicited by Myc overexpression overwhelm the

pro-survival Bcl-2 proteins that this agent cannot inhibit, namely Mcl-1 and possibly A1, and perhaps also directly activate Bax or Bak. The resulting apoptosis is expected to reduce the

target population for transformation and also eliminate nascent neoplastic clones.20 It will be interesting to test whether loss of Bim, Puma or both of these BH3-only proteins will abrogate

the ability of ABT-737 to inhibit Myc-driven lymphoma development. It is interesting to note that, although ABT-737 greatly impedes the emergence of Myc-induced lymphomas (Figure 4), the

fully fledged pre-B/B-cell malignancies induced solely by the E_μ_-_myc_ transgene are instead highly refractory to treatment with ABT-737.35 The loss in sensitivity may be because the

malignant E_μ_-_myc_ lymphomas commonly have acquired mutations that block function of p53 or ARF,36 impairing their ability to induce the key p53 pro-apoptotic targets Puma and Noxa,37, 38

which together with Bim are critical for the killing of E_μ_-_myc_ lymphoma cells by chemotherapeutic drugs that cause DNA damage.39 Alternatively, some E_μ_-_myc_ lymphomas may be resistant

to ABT-737 because they have acquired mutations that increase the level of Mcl-1 or A1, which ABT-737 does not inhibit. Mcl-1 levels can be augmented by higher copy numbers of its gene,40

by loss of one of the E3 ubiquitin ligases that promote its proteasomal degradation, such as the tumour suppressor FBW741 or conversely by upregulation of one of its deubiquitinases, such as

USP9x.42 Our findings indicate that drugs that target the expression or activity of specific pro-survival Bcl-2 family members, such as the BH3 mimetic ABT-73722 and the closely related

compound ABT-263,43 which is currently undergoing clinical trials, may not only help to eliminate established cancers but may also prevent the development of certain types of tumours by

unleashing the pro-apoptotic impetus of the oncogenic changes they have sustained (e.g. enforced c-Myc expression). Hence, in principle, such drugs could contribute to the management of

individuals with hereditary predispositions to malignancy, such as individuals bearing germline mutations in _BRCA1_, _BRCA2_ or _p53_. With p53-deficient mice, a model for the inherited

human Li-Fraumeni syndrome, we recently tested prophylaxis with ABT-737, although the relevant Bcl-2 pro-survival target(s) for this condition is (are) unknown. ABT-737 treatment did

significantly delay lymphoma development but only in the _γ_-irradiated _p53_−/− mice.44 Perhaps in p53 heterozygous individuals, a BH3 mimetic targeting Mcl-1 or A1 would have a more marked

prophylactic effect. In any case, our present results strongly suggest that BH3 mimetics could have a prophylactic role in certain familial cancer syndromes, particularly those in which

deregulated Myc expression contributes to neoplastic progression. With certain types of malignancies, BH3 mimetics might also have a prophylactic role in reducing the frequency of

recurrences. In human acute B-lymphoblastic leukaemias, which derive from cells of the same stage as those yielding the E_μ_-_myc_ lymphomas, genome-wide comparisons of paired primary and

relapse samples suggest that relapses often arise from distinct minor subclones present at diagnosis but lacking some of the mutations present in the predominant diagnostic clone.45, 46

Conceivably, some recurrences arise from clones that, like the preneoplastic Myc-driven pro-B/pre-B lymphocytes, still rely initially upon endogenous levels of particular pro-survival

proteins. If so, prophylactic use of a BH3 mimetic could prevent the re-emergence of malignant clones. A concern for prophylactic use of a BH3 mimetic is the possibility of unacceptable

toxicities in some normal cells. However, the only recognised toxicity so far identified in clinical trials with ABT-263 is an acute thrombocytopenia,24 produced by its on-target inhibition

of Bcl-xL, the level of which controls platelet lifespan.47 Fortunately, as the drop in platelets is transient, dose dependent and reduced during chronic treatment,47 the thrombocytopenia

can be largely managed by dose and scheduling. Whether other adverse effects would arise on prolonged prophylactic treatment remains to be determined by clinical trial. Another issue for the

prophylactic use of BH3 mimetics would be whether they compromise defence against infections by damaging the immune system. For example, ABT-737 treatment of mice reduces certain lymphoid

populations and some newly arising immune responses but not those already established.48 However, the impact on immunity will depend greatly upon the specificity of the BH3 mimetic. For

example, conditional deletion of _bcl-x_ in antigen-activated B cells of mice had no effect on the development of germinal centre or memory B cells and little on plasma cells, whereas

deletion of _mcl-1_ essentially abolished all three populations.49 Hence, a BH3 mimetic that targets Bcl-xL would not be expected to compromise immunity unacceptably and could have

prophylactic potential. MATERIALS AND METHODS MICE Experiments with mice were conducted according to the guidelines of the Walter and Eliza Hall Institute Animal Ethics Committee. E_μ_-_myc_

transgenic mice have been described earlier.13, 14 The strain had been backcrossed to the C57BL/6-Ly5.2 genetic background for >30 generations. HAEMOPOIETIC STEM CELL RECONSTITUTION AND

PROPHYLACTIC TREATMENT OF PRELEUKAEMIC MICE WITH ABT-737 E_μ_-_myc_ E14.5 (Ly5.2) embryos were generated by mating E_μ_-_myc_ transgenic males with (wt) C57BL/6-Ly5.2 females. The day when

the vaginal plug was detected was deemed embryonic day 0.5. Embryos from timed matings were harvested at E14.5 and genotyped by PCR on tail-derived DNA. Immediately before injection, single

cell suspensions were prepared from fetal livers and ∼2 × 106 cells injected into the tail vein of lethally irradiated (2 × 5.5 Gy at 3 h interval) C57BL/6-Ly5.1 mice. Mice were maintained

on neomycin sulphate-supplemented drinking water for 14 days post irradiation to prevent infection. Six weeks post reconstitution, the recipients were treated either once with ABT-737 (75 

mg/kg body weight) or vehicle, or treated with ABT-737 for 2 or 8 week (75 mg/kg, three times per week; see the scheme in Figure 1). LYMPHOMA MONITORING AND STATISTICAL ANALYSIS

Reconstituted mice that had been treated with ABT-737 or vehicle were monitored daily for signs of lymphoma development. Tumour-free survival was defined as the time from lethal irradiation

and haemopoietic reconstitution with fetal liver cells to the time the animal was deemed ill by an experienced animal technician. To verify that mice used for preleukaemic analysis lacked

malignant cells, 1 × 106 of their bone marrow and/or spleen cells were transplanted into non-irradiated histocompatible recipient mice, which were then monitored for 90 days for the

development of any tumour. Kaplan–Meier curves were constructed using GraphPad Prism (version 5.0; GraphPad Software Inc., La Jolla, CA, USA), and statistical analysis performed using a

Log-rank (Mantel-Cox) test. ANALYSIS OF THE HAEMOPOIETIC SYSTEM OF RECONSTITUTED MICE TREATED WITH ABT-737 OR VEHICLE Bone marrow (both femora), spleen and lymph nodes (combined mesenteric,

inguinal and axillary) were harvested from the reconstituted mice that had been treated with one dose of ABT-737 or vehicle. Single cell suspensions were prepared and total cell numbers

determined by trypan blue staining and counting in a haemocytometer as described earlier.50 Absolute numbers in each cellular compartment were calculated by multiplying the percentage of a

cell type (as determined by fluorescence-activated cell sorting (FACS) analysis) by the total organ cellularity. Donor-derived cell numbers were calculated by multiplying the percentage of

donor-derived (Ly5.2+) cells by the total organ cellularity. Peripheral blood was harvested via retro-orbital bleed or at the time of killing by cardiac puncture and collected into

heparinized vessels. The numbers of total white blood cells were determined by using an Advia 120 blood analyser equipped with a mouse analysis software module (Bayer/Siemens, Deerfield, IL,

USA). IMMUNOFLUORESCENT STAINING, FLOW CYTOMETRIC ANALYSIS AND CELL SORTING Before FACS-based immuno-phenotyping, peripheral blood was depleted of red blood cells by incubation (2 × 5 min)

at 4 °C with red cell lysis buffer (56 mM NH4Cl, 0.1 mM EDTA, 12 mM NaHCO3, pH 7.3). To prevent non-specific antibody binding, cells were incubated in the presence of 2.4G2 (anti-Fc_γ_RII)

antibody plus 2% normal rat serum. Host (Ly5.1+) and donor-derived (Ly5.2+) cells were discriminated by staining with anti-Ly5.1 (A201.1) and anti-Ly5.2 (5.450.15.2) monoclonal antibodies.

Preleukaemic pro-B (B220+c-Kit+sIgM−sIgD−), pre-B (B220+c-Kit−sIgM−sIgD−) and sIg+ (B220+c-Kit-sIgM+sIgD+) B-lymphoid populations were purified by FACS sorting by staining with monoclonal

antibodies to: B220 (RA3-6B2), c-Kit (ACK2 or ACK4), IgM (5.1 or 333.12) and IgD (11-26C). Antibodies were produced in our laboratory and conjugated to biotin, fluorescein isothiocyanate

(FITC, both from Molecular Probes, Inc., Eugene, OR, USA), cyanine 5 (Cy5, Amersham Biosciences, Piscataway, NJ, USA), R-phycoerythin (R-PE) or allophycocyanin (APC, both from Prozyme,

Hayward, CA, USA) according to the manufacturers’ instructions. Biotinylated antibodies were detected by secondary staining with FITC-, PE- or Tricolor-coupled streptavidin (Caltag

Laboratories, Carlsbad, CA, USA). Dead cells were excluded by staining with propidium iodide (PI, 2 _μ_g/ml). Purification of B-lymphoid subpopulations was performed by multi-parameter FACS

sorting using a MoFlo (DAKO Cytomation Ltd, Ely, Cambridgeshire, UK) or DiVa (BD Biosciences, San Jose, CA, USA) high-speed flow cytometer. CELL CULTURE AND CELL SURVIVAL ANALYSIS E_μ_-_myc_

pre-B or B-lymphoma cells were cultured in a humidified incubator (10% CO2) at 37 °C in flat bottom 96-well microtitre plates at 2–5 × 104 cells/100 _μ_l (per time point) in the

high-glucose version of Dulbecco’s modified Eagle’s medium supplemented with 250 _μ_M L-asparagine, 50 _μ_M 2-mercaptoethanol and 10% heat-inactivated fetal calf serum (FCS, JRH Biosciences

Pty Ltd, Melbourne, VIC, Australia). Cells were cultured in simple medium (no added growth factors) to assess the effects of cytokine deprivation. Cells were harvested after 4 h and the

viability determined by staining with PI and FITC-conjugated annexin-V followed by flow cytometric analysis using a FACScan analyser (BD Biosciences). TUNEL ANALYSIS ON BONE MARROW Sternum

specimens were collected in 80% Histochoice for histological analysis. Sections for TUNEL analysis were de-paraffinised, treated with proteinase K (20 _μ_g/ml for 10 min at room temperature)

and endogenous peroxidases blocked by incubation in 10% hydrogen peroxide in methanol for 5 min at room temperature. They were then incubated with 0.6 U/_μ_l terminal deoxynucleotidyl

transferase (Promega, Madison, WI, USA), 20 _μ_M biotin-16-dUTP (Roche, Castle Hill, NSW, Australia), 1 mM CoCl2 (Sigma-Aldrich Pty, Sydney, NSW, Australia) in terminal transferase buffer

(Promega) for 1 h at 37 °C, followed by blocking with 2% FCS (FCS, JRH Biosciences) in PBS for 10 min at room temperature. The blocking solution was then removed and Vectorstain ABC (Vector

Laboratories, Burlingame, CA, USA) reagents applied according to the manufacturer’s instructions. Sections were stained using DAB reagent (Vector Laboratories) according to the

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ACKNOWLEDGEMENTS We thank Drs S Cory, D Huang and P Bouillet for providing mice, reagents and advice; M Cook, for preparing the ABT-737 for injections; K Vella, G Siciliano, D Cooper, N

Iannarella, J Coughlin and Lisa Reid for animal care and help with ABT-737 treatment; J Corbin for automated blood analysis; B Helbert and C Young for genotyping; Dr. F Battye and his team

for cell sorting, Dr. S Mihajlovic and his team for histological services and D Quilici, T Nikolaou and G Thomas for irradiation. This work was supported by grants and fellowships from the

Cancer Council of Victoria (to PNK), the National Health and Medical Research Council (Program Grant No. 461221, NHMRC Australia Fellowship), the Leukemia and Lymphoma Society (SCOR Grant

No. 7413) and operational infrastructure grants through the Australian Government IRISS and the Victorian State Government OIS. We acknowledge collaboration with Genentech and Abbott

Laboratories on the development of BH3 mimetic drugs. AUTHOR INFORMATION Author notes * P N Kelly, S Grabow, J M Adams & A Strasser Present address: Current address: Metabolism Branch,

National Cancer Institute/NIH, Bethesda, MD 20892, USA, * P N Kelly: PNK and SG share first authorship. * JMA and AS share senior authorship. AUTHORS AND AFFILIATIONS * Molecular Genetics of

Cancer, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia P N Kelly, S Grabow, A R D Delbridge, J M Adams & A Strasser * Department of Medical

Biology, Melbourne University, Melbourne, Victoria, Australia P N Kelly, S Grabow, A R D Delbridge, J M Adams & A Strasser Authors * P N Kelly View author publications You can also

search for this author inPubMed Google Scholar * S Grabow View author publications You can also search for this author inPubMed Google Scholar * A R D Delbridge View author publications You

can also search for this author inPubMed Google Scholar * J M Adams View author publications You can also search for this author inPubMed Google Scholar * A Strasser View author publications

You can also search for this author inPubMed Google Scholar CORRESPONDING AUTHORS Correspondence to J M Adams or A Strasser. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no

conflict of interest. ADDITIONAL INFORMATION Edited by G Melino RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Kelly, P., Grabow, S., Delbridge, A. _et

al._ Prophylactic treatment with the BH3 mimetic ABT-737 impedes Myc-driven lymphomagenesis in mice. _Cell Death Differ_ 20, 57–63 (2013). https://doi.org/10.1038/cdd.2012.92 Download

citation * Received: 24 April 2012 * Revised: 14 June 2012 * Accepted: 20 June 2012 * Published: 20 July 2012 * Issue Date: January 2013 * DOI: https://doi.org/10.1038/cdd.2012.92 SHARE THIS

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Provided by the Springer Nature SharedIt content-sharing initiative KEYWORDS * Myc * Bcl-2 family * apoptosis * tumorigenesis * cancer prevention