Pten mediates Myc oncogene dependence in a conditional zebrafish model of T cell acute lymphoblastic leukemia

Gutiérrez, Alejandro; Grebliunaite, Ruta; Feng, Hui; Kozakewich, Elena; Zhu, Shizhen; Guo, Feng; Payne, Elspeth; Mansour, Marc R.; Dahlberg, Suzanne E.; Neuberg, Donna; Hertog, Jeroen den; Prochownik, Edward V.; Testa, Joseph R.; Harris, Marian H.; Kanki, John P.; Look, A. Thomas

doi:10.1083/jcb1941oia4

Cited by 20 publications

(31 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Circular rag2:myr-mAkt2 plasmid DNA (30 pg) was microinjected along with I-SceI meganuclease (New England Biolabs) into one-cell stage zebrafish embryos from the AB wild-type strain, as previously described (26). Immunohistochemistry.…”

Section: Methodsmentioning

confidence: 99%

Aberrant AKT activation drives well-differentiated liposarcoma

Gutiérrez

Snyder

Mariño-Enríquez³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

Well-differentiated liposarcoma (WDLPS), one of the most common human sarcomas, is poorly responsive to radiation and chemotherapy, and the lack of animal models suitable for experimental analysis has seriously impeded functional investigation of its pathobiology and development of effective targeted therapies. Here, we show that zebrafish expressing constitutively active Akt2 in mesenchymal progenitors develop WDLPS that closely resembles the human disease. Tumor incidence rates were 8% in p53 wild-type zebrafish, 6% in p53 heterozygotes, and 29% in p53-homozygous mutant zebrafish (P = 0.013), indicating that aberrant Akt activation collaborates with p53 mutation in WDLPS pathogenesis. Analysis of primary clinical specimens of WDLPS, and of the closely related dedifferentiated liposarcoma (DDLPS) subtype, revealed immunohistochemical evidence of AKT activation in 27% of cases. Western blot analysis of a panel of cell lines derived from patients with WDLPS or DDLPS revealed robust AKT phosphorylation in all cell lines examined, even when these cells were cultured in serum-free media. Moreover, BEZ235, a small molecule inhibitor of PI3K and mammalian target of rapamycin that effectively inhibits AKT activation in these cells, impaired viability at nanomolar concentrations. Our findings are unique in providing an animal model to decipher the molecular pathogenesis of WDLPS, and implicate AKT as a previously unexplored therapeutic target in this chemoresistant sarcoma.L iposarcoma is the most common sarcoma of humans, affecting ∼2,000 individuals per year in the United States (1). These tumors are classified into five histopathologic subtypes, with well-differentiated liposarcoma (WDLPS) accounting for ∼50% of cases, and dedifferentiated liposarcoma (DDLPS), a closely related subtype that appears to arise from further malignant progression of WDLPS, accounting for an additional 9% to 18% of cases (1-3). Liposarcomas are generally thought to arise de novo rather than from preexisting benign lesions, and most patients lack recognized causative factors. Although complete surgical resection can be curative, WDLPS often develops in deep anatomic locations, such as the retroperitoneum or mediastinum, where its propensity to enwrap vital structures typically makes complete surgical resection difficult or impossible, leading to high morbidity and mortality rates (1, 4). Radiation and chemotherapy have limited efficacy in the treatment of WDLPS (5, 6). Indeed, there are no systemic therapeutic regimens known to improve survival when complete surgical resection is not feasible, underscoring the need for an improved molecular understanding of WDLPS to stimulate the development of effective targeted therapies.The MDM2-p53 pathway plays a prominent role in WDLPS pathogenesis, with the vast majority of human tumors harboring either MDM2 amplifications or p53 mutations (6-10). Moreover, individuals with germ-line p53 mutations appear to be at increased risk of WDLPS development at a very young age (11).Regions of chromosome 12q13...

show abstract

Section: Methodsmentioning

confidence: 99%

Aberrant AKT activation drives well-differentiated liposarcoma

Gutiérrez

Snyder

Mariño-Enríquez³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

show abstract

“…cMYC-ER zebrafish 22 were crossed with lck:EGFP zebrafish and leukemic adults were identified via fluorescence microscopy for T-ALL dissemination. Leukemic adults were treated either with vehicle or LDK on a 2-day-on, 1-day-off treatment regimen with daily water changes.…”

Section: Leukemic Zebrafish Experimentsmentioning

confidence: 99%

Zebrafish screen identifies novel compound with selective toxicity against leukemia

Ridges

Heaton

Joshi

et al. 2012

Blood

135

110

View full text Add to dashboard Cite

To detect targeted antileukemia agents we have designed a novel, high-content in vivo screen using genetically engineered, T-cell reporting zebrafish. We exploited the developmental similarities between normal and malignant T lymphoblasts to screen a small molecule library for activity against immature T cells with a simple visual readout in zebrafish larvae. After screening 26 400 molecules, we identified Lenaldekar (LDK), a compound that eliminates immature T cells in developing zebrafish without affecting the cell cycle in other cell types. LDK is well tolerated in vertebrates and induces longterm remission in adult zebrafish with cMYCinduced T-cell acute lymphoblastic leukemia (T-ALL). LDK causes dephosphorylation of members of the PI3 kinase/AKT/mTOR pathway and delays sensitive cells in late mitosis. Among human cancers, LDK selectively affects survival of hematopoietic malignancy lines and primary leukemias, including therapy-refractory B-ALL and chronic myelogenous leukemia samples, and inhibits growth of human T-ALL xenografts. This work demonstrates the utility of our method using zebrafish for antineoplastic candidate drug identification and suggests a new approach for targeted leukemia therapy. Although our efforts focused on leukemia therapy, this screening approach has broad implications as it can be translated to other cancer types involving malignant degeneration of developmentally arrested cells. (Blood. 2012;119(24):5621-5631) IntroductionThe yearly incidence in the US for all leukemia types, including acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), and chronic myelogenous leukemia (CML), was estimated at more than 40 000 men and women in 2010, with a yearly death rate of 50%. 1 More than 2000 cases of ALL are diagnosed in US children every year, making it the most common childhood cancer. 2 T-cell ALL (T-ALL) represents approximately 15% and 25% of pediatric and adult ALL cases, respectively. 3 Although leukemia treatment has become increasingly efficient over the past 50 years, mortality from ALL is still 20% for children and more than 40% for adults, and T-ALL has been more difficult to treat than B-cell ALL (B-ALL). 4 Currently, research efforts are devoted to molecularbased risk stratification of patients and the development of targeted therapies to limit side effects [5][6][7] and to increase treatment efficacy.Development of targeted cancer therapies typically requires knowledge of the molecular target. 8 In the absence thereof, an alternative approach may use a robust readout designed to screen large numbers of compounds for specific effects 9 against the malignant cell type in question. More than 50% of patients with T-ALL have deregulated NOTCH1, 10 and in a recent study 47% had mutations in the PI3 kinase/AKT/mTOR (P/A/mT) pathway. 11 NOTCH1 signaling requires proteolytic cleavage by ␥-secretase and other proteases 12 to release the intracytoplasmic domain, providing severalpotential targets for therapeutic intervention. Targeted treatment approaches for T-ALL using...

show abstract

“…Using an inducible MYC-dependent zebrafish T-ALL model, Gutierrez et al found that established tumors regressed when MYC expression was turned off. This effect was circumvented by activating PI3K-AKT signaling, 66 showing that AKT activation is an important downstream effector of MYC which may drive GSI resistance. Moreover, the MYC gene is an important…”

mentioning

confidence: 99%

The relevance of PTEN-AKT in relation to NOTCH1-directed treatment strategies in T-cell acute lymphoblastic leukemia

et al. 2016

View full text Add to dashboard Cite

T-cell acute lymphoblastic leukemia (T-ALL) is a cancer of developing T cells in the thymus. T-ALL is characterized by chromosomal rearrangements. These rearrangements can lead to the aberrant activation of oncogenic transcription factors by placing their genes under the control of promoters and/or enhancers of Tcell receptor genes, the BCL11B gene, or other genes; occasionally, these rearrangements can give rise to oncogenic fusion proteins. The activated oncogenic transcription factors include TAL1 and LMO2 (and related family members), TLX1, TLX3, NKX2-1, HOXA, and MEF2C; in addition, certain oncogenic fusion proteins can directly activate the HOXA or MEF2C genes.1,2 Oncogenic proteins facilitate the developmental arrest of pre-leukemic immature T cells. We previously proposed that these chromosomal rearrangements should be classified as type A aberrations, as they are generally considered to be the driving oncogenic event associated with unique expression profiles.2 Based upon their gene expression signatures, T-ALL can be classified into the following four major subtypes: ETP-ALL, TLX, proliferative, and TALLMO. [3][4][5] Maturation arrest induces a pre-leukemic condition in which additional mutations can give rise to T-ALL.1,2 These secondary mutations are not necessarily clonal events and are often selected during disease progression or post-treatment T he tumor suppressor phosphatase and tensin homolog (PTEN) negatively regulates phosphatidylinositol 3-kinase (PI3K)-AKT signaling and is often inactivated by mutations (including deletions) in a variety of cancer types, including T-cell acute lymphoblastic leukemia. Here we review mutation-associated mechanisms that inactivate PTEN together with other molecular mechanisms that activate AKT and contribute to T-cell leukemogenesis. In addition, we discuss how Pten mutations in mouse models affect the efficacy of gamma-secretase inhibitors to block NOTCH1 signaling through activation of AKT. Based on these models and on observations in primary diagnostic samples from patients with T-cell acute lymphoblastic leukemia, we speculate that PTEN-deficient cells employ an intrinsic homeostatic mechanism in which PI3K-AKT signaling is dampened over time. As a result of this reduced PI3K-AKT signaling, the level of AKT activation may be insufficient to compensate for NOTCH1 inhibition, resulting in responsiveness to gamma-secretase inhibitors. On the other hand, de novo acquired PTEN-inactivating events in NOTCH1-dependent leukemia could result in temporary, strong activation of PI3K-AKT signaling, increased glycoly sis and glutaminolysis, and consequently gamma-secretase inhibitor resistance. Due to the central role of PTEN-AKT signaling and in the resistance to NOTCH1 inhibition, AKT inhibitors may be a promising addition to current treatment protocols for T-cell acute lymphoblastic leukemia.

show abstract

Pten mediates Myc oncogene dependence in a conditional zebrafish model of T cell acute lymphoblastic leukemia

Cited by 20 publications

References 46 publications

Aberrant AKT activation drives well-differentiated liposarcoma

Aberrant AKT activation drives well-differentiated liposarcoma

Zebrafish screen identifies novel compound with selective toxicity against leukemia

The relevance of PTEN-AKT in relation to NOTCH1-directed treatment strategies in T-cell acute lymphoblastic leukemia

Contact Info

Product

Resources

About