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Carlock C, Bai Y, Paige-Hood A, Li Q, Nguele Meke F, Zhang ZY. PRL2 inhibition elevates PTEN protein and ameliorates progression of acute myeloid leukemia. JCI Insight 2023; 8:e170065. [PMID: 37665633 PMCID: PMC10619439 DOI: 10.1172/jci.insight.170065] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 08/23/2023] [Indexed: 09/06/2023] Open
Abstract
Overexpression of phosphatases of regenerating liver 2 (PRL2), detected in numerous diverse cancers, is often associated with increased severity and poor patient prognosis. PRL2-catalyzed tyrosine dephosphorylation of the tumor suppressor PTEN results in increased PTEN degradation and has been identified as a mechanism underlying PRL2 oncogenic activity. Overexpression of PRL2, coincident with reduced PTEN protein, is frequently observed in patients with acute myeloid leukemia (AML). In the current study, a PTEN-knockdown AML animal model was generated to assess the effect of conditional PRL2 inhibition on the level of PTEN protein and the development and progression of AML. Inhibition of PRL2 resulted in a significant increase in median animal survival, from 40 weeks to greater than 60 weeks. The prolonged survival reflected delayed expansion of aberrantly differentiated hematopoietic stem cells into leukemia blasts, resulting in extended time required for clinically relevant leukemia blast accumulation in the BM niche. Leukemia blast suppression following PRL2 inhibition was correlated with an increase in PTEN and downregulation of AKT/mTOR-regulated pathways. These observations directly established, in a disease model, the viability of PRL2 inhibition as a therapeutic strategy for improving clinical outcomes in AML and potentially other PTEN-deficient cancers by slowing cancer progression.
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Affiliation(s)
| | - Yunpeng Bai
- Department of Medicinal Chemistry and Molecular Pharmacology
| | | | - Qinglin Li
- Department of Medicinal Chemistry and Molecular Pharmacology
| | | | - Zhong-Yin Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology
- Department of Chemistry
- Institute for Cancer Research, and
- Institute for Drug Discovery, Purdue University, West Lafayette, Indiana, USA
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2
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Engel BJ, Paolillo V, Uddin MN, Gonzales KA, McGinnis KM, Sutton MN, Patnana M, Grindel BJ, Gores GJ, Piwnica-Worms D, Beretta L, Pisaneschi F, Gammon ST, Millward SW. Gender Differences in a Mouse Model of Hepatocellular Carcinoma Revealed Using Multi-Modal Imaging. Cancers (Basel) 2023; 15:3787. [PMID: 37568603 PMCID: PMC10417617 DOI: 10.3390/cancers15153787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/14/2023] [Accepted: 07/18/2023] [Indexed: 08/13/2023] Open
Abstract
The worldwide incidence of hepatocellular carcinoma (HCC) continues to rise, in part due to poor diet, limited exercise, and alcohol abuse. Numerous studies have suggested that the loss or mutation of PTEN plays a critical role in HCC tumorigenesis through the activation of the PI3K/Akt signaling axis. The homozygous knockout of PTEN in the livers of mice results in the accumulation of fat (steatosis), inflammation, fibrosis, and eventually progression to HCC. This phenotype bears a striking similarity to non-alcoholic steatohepatitis (NASH) which is thought to occupy an intermediate stage between non-alcoholic fatty liver disease (NAFLD), fibrosis, and HCC. The molecular and physiological phenotypes that manifest during the transition to HCC suggest that molecular imaging could provide a non-invasive screening platform to identify the hallmarks of HCC initiation prior to the presentation of clinical disease. We have carried out longitudinal imaging studies on the liver-specific PTEN knockout mouse model using CT, MRI, and multi-tracer PET to interrogate liver size, steatosis, inflammation, and apoptosis. In male PTEN knockout mice, significant steatosis was observed as early as 3 months using both magnetic resonance spectroscopy (MRS) and computed tomography (CT). Enhanced uptake of the apoptosis tracer 18F-TBD was also observed in the livers of male PTEN homozygous knockout mice between 3 and 4 months of age relative to heterozygous knockout controls. Liver uptake of the inflammation tracer [18F]4FN remained relatively low and constant over 7 months in male PTEN homozygous knockout mice, suggesting the suppression of high-energy ROS/RNS with PTEN deletion relative to heterozygous males where the [18F]4FN liver uptake was elevated at early and late time points. All male PTEN homozygous mice developed HCC lesions by month 10. In contrast to the male cohort, only 20% (2 out of 10) of female PTEN homozygous knockout mice developed HCC lesions by month 10. Steatosis was significantly less pronounced in the female PTEN homozygous knockout mice relative to males and could not accurately predict the eventual occurrence of HCC. As with the males, the [18F]4FN uptake in female PTEN homozygous knockout mice was low and constant throughout the time course. The liver uptake of 18F-TBD at 3 and 4.5 months was higher in the two female PTEN knockout mice that would eventually develop HCC and was the most predictive imaging biomarker for HCC in the female cohort. These studies demonstrate the diagnostic and prognostic role of multi-modal imaging in HCC mouse models and provide compelling evidence that disease progression in the PTEN knockout model is highly dependent on gender.
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Affiliation(s)
- Brian J. Engel
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Vincenzo Paolillo
- Cyclotron Radiochemistry Facility, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Md. Nasir Uddin
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Kristyn A. Gonzales
- Department of Molecular and Cellular Oncology, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Kathryn M. McGinnis
- Department of Molecular and Cellular Oncology, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Margie N. Sutton
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Madhavi Patnana
- Department of Abdominal Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Brian J. Grindel
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | | | - David Piwnica-Worms
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Laura Beretta
- Department of Molecular and Cellular Oncology, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Federica Pisaneschi
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases (IMM) at the University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Seth T. Gammon
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Steven W. Millward
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA
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3
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Zhang J, Xiang Z, Malaviarachchi PA, Yan Y, Baltz NJ, Emanuel PD, Liu YL. PTEN is indispensable for cells to respond to MAPK inhibitors in myeloid leukemia. Cell Signal 2018; 50:72-79. [PMID: 29964149 DOI: 10.1016/j.cellsig.2018.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 06/02/2018] [Accepted: 06/06/2018] [Indexed: 12/13/2022]
Abstract
Constitutively activated MAPK and AKT signaling pathways are often found in solid tumors and leukemias. PTEN is one of the tumor suppressors that are frequently found deficient in patients with late-stage cancers or leukemias. In this study we demonstrate that a MAPK inhibitor, PD98059, inhibits both AKT and ERK phosphorylation in a human myeloid leukemia cell line (TF-1), but not in PTEN-deficient leukemia cells (TF-1a). Ectopic expression of wild-type PTEN in myeloid leukemia cells restored cytokine responsiveness at physiological concentrations of GM-CSF (<0.02 ng/mL) and significantly improved cell sensitivity to MAPK inhibitor. We also found that Early Growth Response 1 (EGR1) was constitutively over-expressed in cytokine-independent TF-1a cells, and ectopic expression of PTEN down-regulated EGR1 expression and restored dynamics of EGR1 expression in response to GM-CSF stimulation. Data from primary bone marrow cells from mice with Pten deletion further supports that PTEN is indispensible for myeloid leukemia cells in response to MAPK inhibitors. Finally, We demonstrate that the absence of EGR1 expression dynamics in response to GM-CSF stimulation is one of the mechanisms underlying drug resistance to MAPK inhibitors in leukemia cells with PTEN deficiency. Our data suggest a novel mechanism of PTEN in regulating expression of EGR1 in hematopoietic cells in response to cytokine stimulation. In conclusion, this study demonstrates that PTEN is dispensable for myeloid leukemia cells in response to MAPK inhibitors, and PTEN regulates EGR1 expression and contributes to the cytokine sensitivity in leukemia cells.
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Affiliation(s)
- Jingliao Zhang
- Winthrop P. Rockefeller Cancer Institute, Division of Hematology, Department of Internal Medicine, College of Medicine, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205, United States; Department of Pediatrics, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Tianjin 300020, China
| | - Zhifu Xiang
- Winthrop P. Rockefeller Cancer Institute, Division of Hematology, Department of Internal Medicine, College of Medicine, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205, United States
| | - Priyangi A Malaviarachchi
- Winthrop P. Rockefeller Cancer Institute, Division of Hematology, Department of Internal Medicine, College of Medicine, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205, United States
| | - Yan Yan
- Winthrop P. Rockefeller Cancer Institute, Division of Hematology, Department of Internal Medicine, College of Medicine, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205, United States
| | - Nicholas J Baltz
- Winthrop P. Rockefeller Cancer Institute, Division of Hematology, Department of Internal Medicine, College of Medicine, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205, United States
| | - Peter D Emanuel
- Winthrop P. Rockefeller Cancer Institute, Division of Hematology, Department of Internal Medicine, College of Medicine, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205, United States.
| | - Y Lucy Liu
- Winthrop P. Rockefeller Cancer Institute, Division of Hematology, Department of Internal Medicine, College of Medicine, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205, United States.
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Bhatia S, Daschkey S, Lang F, Borkhardt A, Hauer J. Mouse models for pre-clinical drug testing in leukemia. Expert Opin Drug Discov 2016; 11:1081-1091. [DOI: 10.1080/17460441.2016.1229297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Timing of the loss of Pten protein determines disease severity in a mouse model of myeloid malignancy. Blood 2016; 127:1912-22. [PMID: 26764354 DOI: 10.1182/blood-2015-05-646216] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 01/04/2016] [Indexed: 12/24/2022] Open
Abstract
Juvenile myelomonocytic leukemia (JMML) is an aggressive pediatric mixed myelodysplastic/myeloproliferative neoplasm (MDS/MPN). JMML leukemogenesis is linked to a hyperactivated RAS pathway, with driver mutations in the KRAS, NRAS, NF1, PTPN11, or CBL genes. Previous murine models demonstrated how those genes contributed to the selective hypersensitivity of JMML cells to granulocyte macrophage-colony-stimulating factor (GM-CSF), a unifying characteristic in the disease. However, it is unclear what causes the early death in children with JMML, because transformation to acute leukemia is rare. Here, we demonstrate that loss of Pten (phosphatase and tensin homolog) protein at postnatal day 8 in mice harboring Nf1 haploinsufficiency results in an aggressive MPN with death at a murine prepubertal age of 20 to 35 days (equivalent to an early juvenile age in JMML patients). The death in the mice was due to organ infiltration with monocytes/macrophages. There were elevated activities of protein kinase B (Akt) and mitogen-activated protein kinase (MAPK) in cells at physiological concentrations of GM-CSF. These were more pronounced in mice with Nf1 haploinsufficiency than in littermates with wild-type Nf1,but this model is insufficient to cause cells to be GM-CSF hypersensitive. This new model represents a murine MPN model with features of a pediatric unclassifiable mixed MDS/MPN and mimics many clinical manifestations of JMML in terms of age of onset, aggressiveness, and organ infiltration with monocytes/macrophages. Our data suggest that the timing of the loss of PTEN protein plays a critical role in determining the disease severity in myeloid malignancies. This model may be useful for studying the pathogenesis of pediatric diseases with alterations in the Ras pathway.
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Zhang W, Wang J, Wang Y, Dong F, Zhu M, Wan W, Li H, Wu F, Yan X, Ke X. B7-H3 silencing by RNAi inhibits tumor progression and enhances chemosensitivity in U937 cells. Onco Targets Ther 2015; 8:1721-33. [PMID: 26203263 PMCID: PMC4508088 DOI: 10.2147/ott.s85272] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The role of B7-H3 in acute monocytic leukemia U937 cells has not been thoroughly investigated. MATERIALS AND METHODS B7-H3 knockdown in the U937 cell line was performed using small hairpin (sh)RNA lentivirus transduction. The effects on cell proliferation, cycle, migration, and invasion were investigated by Cell Counting Kit-8 assay, methyl cellulose colony-forming assay, propidium iodide staining, and Transwell assays in vitro. Changes in cell growth inhibition and apoptosis, when combined with chemotherapy drugs, were determined using the Cell Counting Kit-8 and Annexin V-FITC/PI assays. U937 xenograft models were used to assess the effects of B7-H3 on tumorigenicity and the therapeutic effect of B7-H3 knockdown in combination with chemotherapy drugs in vivo. RESULTS Downregulation of B7-H3 significantly decreased U937 cell growth and colony-forming ability. The mean inhibition rate of tumor growth with B7-H3 knockdown was 59.4%, and the expression of both Ki-67 and PCNA in xenografts was significantly reduced. After B7-H3 silencing, the U937 cell cycle was arrested at the G0/G1 phase. The cell migration rate of B7-H3 knockdown cells was reduced more than fivefold, and invasion capacity decreased by 86.7%. B7-H3 RNAi profoundly increased the antitumor effect of chemotherapy in vitro and in vivo. On day 19, inhibition rates of tumor growth in B7-H3 shRNA combined with idarubicin, cytarabine, and idarubicin plus cytarabine were 70.5%, 80.0%, and 90.0%, respectively (P=0.006, P=0.004, and P=0.016, respectively). CONCLUSION B7-H3 may promote U937 cell progression, and shRNA targeting B7-H3 significantly enhances sensitivity to chemotherapeutic drugs. These results may provide new insight into the function of B7-H3 and a promising therapeutic approach targeting B7-H3 in acute monocytic leukemia.
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Affiliation(s)
- Wei Zhang
- Department of Hematology and Lymphoma Research Center, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Jing Wang
- Department of Hematology and Lymphoma Research Center, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Yanfang Wang
- Department of Hematology and Lymphoma Research Center, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Fei Dong
- Department of Hematology and Lymphoma Research Center, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Mingxia Zhu
- Department of Hematology and Lymphoma Research Center, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Wenli Wan
- Department of Hematology and Lymphoma Research Center, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Haishen Li
- Department of Hematology and Lymphoma Research Center, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Feifei Wu
- Department of Hematology and Lymphoma Research Center, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Xinxing Yan
- Department of Hematology and Lymphoma Research Center, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Xiaoyan Ke
- Department of Hematology and Lymphoma Research Center, Peking University Third Hospital, Beijing, People’s Republic of China
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7
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Abstract
Animal models have been invaluable in the efforts to better understand and ultimately treat patients suffering from leukemia. While important insights have been gleaned from these models, limitations must be acknowledged. In this review, we will highlight the various animal models of leukemia and describe their contributions to the improved understanding and treatment of these cancers.
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8
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Nin DS, Ali AB, Okumura K, Asou N, Chen CS, Chng WJ, Khan M. Akt-induced phosphorylation of N-CoR at serine 1450 contributes to its misfolded conformational dependent loss (MCDL) in acute myeloid leukemia of the M5 subtype. PLoS One 2013; 8:e70891. [PMID: 23940660 PMCID: PMC3733915 DOI: 10.1371/journal.pone.0070891] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 06/25/2013] [Indexed: 11/18/2022] Open
Abstract
The nuclear receptor co-repressor (N-CoR) is a key component of the generic co-repressor complex that plays an important role in the control of cellular growth and differentiation. As shown by us recently, the growth suppressive function of N-CoR largely relies on its capacity to repress Flt3, a key regulator of cellular gorwth during normal and malignant hematopoesis. We further demonstrated how de-repression of Flt3 due to the misfolded conformation dependent loss (MCDL) of N-CoR contributed to malignant growth in acute myeloid leukemia (AML). However, the molecular mechanism underlying the MCDL of N-CoR and its implication in AML pathogenesis is not fully understood. Here, we report that Akt-induced phosphorylation of N-CoR at the consensus Akt motif is crucial for its misfolding and subsequent loss in AML (AML-M5). N-CoR displayed significantly higher level of serine specific phosphorylation in almost all AML-M5 derived cells and was subjected to processing by AML-M5 specific aberrant protease activity. To identify the kinase linked to N-CoR phosphorylation, a library of activated kinases was screened with the extracts of AML cells; leading to the identification of Akt as the putative kinase linked to N-CoR phosphorylation. Consistent with this finding, a constitutively active Akt consistently phosphorylated N-CoR leading to its misfolding; while the therapeutic and genetic ablation of Akt largely abrogated the MCDL of N-CoR in AML-M5 cells. Site directed mutagenic analysis of N-CoR identified serine 1450 as the crucial residue whose phosphorylation by Akt was essential for the misfolding and loss of N-CoR protein. Moreover, Akt-induced phosphorylation of N-CoR contributed to the de-repression of Flt3, suggesting a cross talk between Akt signaling and N-CoR misfolding pathway in the pathogenesis of AML-M5. The N-CoR misfolding pathway could be the common downstream thread of pleiotropic Akt signaling activated by various oncogenic insults in some subtypes of leukemia and solid tumors.
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Affiliation(s)
- Dawn Sijin Nin
- Cancer Science Institute of Singapore, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine,
National University of Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of
Medicine, National University of Singapore, Singapore
| | - Azhar Bin Ali
- Cancer Science Institute of Singapore, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore
| | - Koichi Okumura
- Cancer Science Institute of Singapore, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore
| | - Norio Asou
- Department of Haematology, Kumamoto University, Kumamoto, Japan
| | - Chien-Shing Chen
- Division of Hematologyand Oncology, School of Medicine, Loma Linda University, Loma Linda, California, United States of America
| | - Wee Joo Chng
- Cancer Science Institute of Singapore, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine,
National University of Singapore, Singapore
- Department of Haematology-Oncology, National Cancer
Institute of Singapore, National University Health System,
Singapore
| | - Matiullah Khan
- Cancer Science Institute of Singapore, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine,
National University of Singapore, Singapore
- School of Medicine, Asian Institute of Medicine, Science and Technology (AIMST), Bedong, Malaysia
- * E-mail: ,
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9
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Tosato V, Grüning NM, Breitenbach M, Arnak R, Ralser M, Bruschi CV. Warburg effect and translocation-induced genomic instability: two yeast models for cancer cells. Front Oncol 2013; 2:212. [PMID: 23346549 PMCID: PMC3548335 DOI: 10.3389/fonc.2012.00212] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Accepted: 12/20/2012] [Indexed: 11/13/2022] Open
Abstract
Yeast has been established as an efficient model system to study biological principles underpinning human health. In this review we focus on yeast models covering two aspects of cancer formation and progression (i) the activity of pyruvate kinase (PK), which recapitulates metabolic features of cancer cells, including the Warburg effect, and (ii) chromosome bridge-induced translocation (BIT) mimiking genome instability in cancer. Saccharomyces cerevisiae is an excellent model to study cancer cell metabolism, as exponentially growing yeast cells exhibit many metabolic similarities with rapidly proliferating cancer cells. The metabolic reconfiguration includes an increase in glucose uptake and fermentation, at the expense of respiration and oxidative phosphorylation (the Warburg effect), and involves a broad reconfiguration of nucleotide and amino acid metabolism. Both in yeast and humans, the regulation of this process seems to have a central player, PK, which is up-regulated in cancer, and to occur mostly on a post-transcriptional and post-translational basis. Furthermore, BIT allows to generate selectable translocation-derived recombinants ("translocants"), between any two desired chromosomal locations, in wild-type yeast strains transformed with a linear DNA cassette carrying a selectable marker flanked by two DNA sequences homologous to different chromosomes. Using the BIT system, targeted non-reciprocal translocations in mitosis are easily inducible. An extensive collection of different yeast translocants exhibiting genome instability and aberrant phenotypes similar to cancer cells has been produced and subjected to analysis. In this review, we hence provide an overview upon two yeast cancer models, and extrapolate general principles for mimicking human disease mechanisms in yeast.
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Affiliation(s)
- Valentina Tosato
- International Centre for Genetic Engineering and Biotechnology Trieste, Italy
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Tang P, Gao C, Li A, Aster J, Sun L, Chai L. Differential roles of Kras and Pten in murine leukemogenesis. Leukemia 2012. [PMID: 23183424 DOI: 10.1038/leu.2012.316] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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11
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Martelli AM, Chiarini F, Evangelisti C, Cappellini A, Buontempo F, Bressanin D, Fini M, McCubrey JA. Two hits are better than one: targeting both phosphatidylinositol 3-kinase and mammalian target of rapamycin as a therapeutic strategy for acute leukemia treatment. Oncotarget 2012; 3:371-94. [PMID: 22564882 PMCID: PMC3380573 DOI: 10.18632/oncotarget.477] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Phosphatidylinositol 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) are two key components of the PI3K/Akt/mTOR signaling pathway. This signal transduction cascade regulates a wide range of physiological cell processes, that include differentiation, proliferation, apoptosis, autophagy, metabolism, motility, and exocytosis. However, constitutively active PI3K/Akt/mTOR signaling characterizes many types of tumors where it negatively influences response to therapeutic treatments. Hence, targeting PI3K/Akt/mTOR signaling with small molecule inhibitors may improve cancer patient outcome. The PI3K/Akt/mTOR signaling cascade is overactive in acute leukemias, where it correlates with enhanced drug-resistance and poor prognosis. The catalytic sites of PI3K and mTOR share a high degree of sequence homology. This feature has allowed the synthesis of ATP-competitive compounds targeting the catalytic site of both kinases. In preclinical models, dual PI3K/mTOR inhibitors displayed a much stronger cytotoxicity against acute leukemia cells than either PI3K inhibitors or allosteric mTOR inhibitors, such as rapamycin. At variance with rapamycin, dual PI3K/mTOR inhibitors targeted both mTOR complex 1 and mTOR complex 2, and inhibited the rapamycin-resistant phosphorylation of eukaryotic initiation factor 4E-binding protein 1, resulting in a marked inhibition of oncogenic protein translation. Therefore, they strongly reduced cell proliferation and induced an important apoptotic response. Here, we reviewed the evidence documenting that dual PI3K/mTOR inhibitors may represent a promising option for future targeted therapies of acute leukemia patients.
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Affiliation(s)
- Alberto M Martelli
- Department of Human Anatomy, University of Bologna, Cellular Signalling Laboratory, Bologna, Italy.
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12
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Dragojlovic-Munther M, Martinez-Agosto JA. Multifaceted roles of PTEN and TSC orchestrate growth and differentiation of Drosophila blood progenitors. Development 2012; 139:3752-63. [PMID: 22951642 DOI: 10.1242/dev.074203] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The innate plasticity of hematopoietic progenitors is tightly regulated to supply blood cells during normal hematopoiesis and in response to stress or infection. We demonstrate that in the Drosophila lymph gland (LG) the tumor suppressors TSC and PTEN control blood progenitor proliferation through a common TOR- and 4EBP-dependent pathway. Tsc2 or Pten deficiency in progenitors increases TOR signaling and causes LG overgrowth by increasing the number of actively dividing cells that accumulate high levels of phosphorylated (p) 4EBP during a critical window of growth. These phenotypes are associated with increased reactive oxygen species (ROS) levels in the LG, and scavenging ROS in progenitors is sufficient to rescue overgrowth. Blood progenitor number is also sensitive to starvation and hypoxia in a TOR-dependent manner. Differences between Tsc1/2 and Pten function become apparent at later stages. Loss of Tsc1/2 autonomously increases p4EBP and decreases pAKT levels, expands the number of intermediate progenitors and limits terminal differentiation, except for a late induction of lamellocytes. By contrast, absence of PTEN increases p4EBP and pAKT levels and induces myeloproliferative expansion of plasmatocytes and crystal cells. This increased malignancy is associated with non-autonomous increases in p4EBP levels within peripheral differentiating hemocytes, culminating in their premature release into circulation and demonstrating potential non-autonomous effects of Pten dysfunction on malignancy. This study highlights mechanistic differences between TSC and PTEN on TOR function and demonstrates the multifaceted roles of a nutrient-sensing pathway in orchestrating proliferation and differentiation of myeloid-specific blood progenitors through regulation of ROS levels and the resulting myeloproliferative disorder when dysregulated.
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13
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McCubrey JA, Steelman LS, Kempf CR, Chappell WH, Abrams SL, Stivala F, Malaponte G, Nicoletti F, Libra M, Bäsecke J, Maksimovic-Ivanic D, Mijatovic S, Montalto G, Cervello M, Cocco L, Martelli AM. Therapeutic resistance resulting from mutations in Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR signaling pathways. J Cell Physiol 2011; 226:2762-81. [PMID: 21302297 DOI: 10.1002/jcp.22647] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chemotherapy remains a commonly used therapeutic approach for many cancers. Indeed chemotherapy is relatively effective for treatment of certain cancers and it may be the only therapy (besides radiotherapy) that is appropriate for certain cancers. However, a common problem with chemotherapy is the development of drug resistance. Many studies on the mechanisms of drug resistance concentrated on the expression of membrane transporters and how they could be aberrantly regulated in drug resistant cells. Attempts were made to isolate specific inhibitors which could be used to treat drug resistant patients. Unfortunately most of these drug transporter inhibitors have not proven effective for therapy. Recently the possibilities of more specific, targeted therapies have sparked the interest of clinical and basic researchers as approaches to kill cancer cells. However, there are also problems associated with these targeted therapies. Two key signaling pathways involved in the regulation of cell growth are the Ras/Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR pathways. Dysregulated signaling through these pathways is often the result of genetic alterations in critical components in these pathways as well as mutations in upstream growth factor receptors. Furthermore, these pathways may be activated by chemotherapeutic drugs and ionizing radiation. This review documents how their abnormal expression can contribute to drug resistance as well as resistance to targeted therapy. This review will discuss in detail PTEN regulation as this is a critical tumor suppressor gene frequently dysregulated in human cancer which contributes to therapy resistance. Controlling the expression of these pathways could improve cancer therapy and ameliorate human health.
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Affiliation(s)
- James A McCubrey
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, North Carolina 27858, USA.
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Pretreatment with phosphatase and tensin homolog deleted on chromosome 10 (PTEN) inhibitor SF1670 augments the efficacy of granulocyte transfusion in a clinically relevant mouse model. Blood 2011; 117:6702-13. [PMID: 21521784 DOI: 10.1182/blood-2010-09-309864] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The clinical outcome of granulocyte transfusion therapy is often hampered by short ex vivo shelf life, inefficiency of recruitment to sites of inflammation, and poor pathogen-killing capability of transplanted neutrophils. Here, using a recently developed mouse granulocyte transfusion model, we revealed that the efficacy of granulocyte transfusion can be significantly increased by elevating intracellular phosphatidylinositol (3,4,5)-trisphosphate signaling with a specific phosphatase and tensin homolog deleted on chromosome 10 (PTEN) inhibitor SF1670. Neutrophils treated with SF1670 were much sensitive to chemoattractant stimulation. Neutrophil functions, such as phagocytosis, oxidative burst, polarization, and chemotaxis, were augmented after SF1670 treatment. The recruitment of SF1670-pretreated transfused neutrophils to the inflamed peritoneal cavity and lungs was significantly elevated. In addition, transfusion with SF1670-treated neutrophils led to augmented bacteria-killing capability (decreased bacterial burden) in neutropenic recipient mice in both peritonitis and bacterial pneumonia. Consequently, this alleviated the severity of and decreased the mortality of neutropenia-related pneumonia. Together, these observations demonstrate that the innate immune responses can be enhanced and the severity of neutropenia-related infection can be alleviated by augmenting phosphatidylinositol (3,4,5)-trisphosphate in transfused neutrophils with PTEN inhibitor SF1670, providing a therapeutic strategy for improving the efficacy of granulocyte transfusion.
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Targeting the translational apparatus to improve leukemia therapy: roles of the PI3K/PTEN/Akt/mTOR pathway. Leukemia 2011; 25:1064-79. [PMID: 21436840 DOI: 10.1038/leu.2011.46] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
It has become apparent that regulation of protein translation is an important determinant in controlling cell growth and leukemic transformation. The phosphoinositide 3-kinase (PI3K)/phosphatase and tensin homologue deleted on chromosome ten (PTEN)/Akt/mammalian target of rapamycin (mTOR) pathway is often implicated in sensitivity and resistance to therapy. Dysregulated signaling through the PI3K/PTEN/Akt/mTOR pathway is often the result of genetic alterations in critical components in this pathway as well as mutations at upstream growth factor receptors. Furthermore, this pathway is activated by autocrine transformation mechanisms. PTEN is a critical tumor suppressor gene and its dysregulation results in the activation of Akt. PTEN is often mutated, silenced and is often haploinsufficient. The mTOR complex1 (mTORC1) regulates the assembly of the eukaryotic initiation factor4F complex, which is critical for the translation of mRNAs that are important for cell growth, prevention of apoptosis and transformation. These mRNAs have long 5'-untranslated regions that are G+C rich, rendering them difficult to translate. Elevated mTORC1 activity promotes the translation of these mRNAs via the phosphorylation of 4E-BP1. mTORC1 is a target of rapamycin and novel active-site inhibitors that directly target the TOR kinase activity. Although rapamycin and novel rapalogs are usually cytostatic and not cytotoxic for leukemic cells, novel inhibitors that target the kinase activities of PI3K and mTOR may prove more effective for leukemia therapy.
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Martelli AM, Evangelisti C, Chiarini F, Grimaldi C, McCubrey JA. The emerging role of the phosphatidylinositol 3-kinase/ akt/mammalian target of rapamycin signaling network in cancer stem cell biology. Cancers (Basel) 2010; 2:1576-96. [PMID: 24281174 PMCID: PMC3837323 DOI: 10.3390/cancers2031576] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 08/16/2010] [Indexed: 12/23/2022] Open
Abstract
The cancer stem cell theory entails the existence of a hierarchically organized, rare population of cells which are responsible for tumor initiation, self-renewal/maintenance, and mutation accumulation. The cancer stem cell proposition could explain the high frequency of cancer relapse and resistance to currently available therapies. The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway regulates a wide array of physiological cell functions which include differentiation, proliferation, survival, metabolism, autophagy, and motility. Dysregulated PI3K/Akt/mTOR signaling has been documented in many types of neoplasias. It is now emerging that this signaling network plays a key role in cancer stem cell biology. Interestingly, cancer stem cells displayed preferential sensitivity to pathway inhibition when compared to healthy stem cells. This observation provides the proof-of-principle that functional differences in signaling pathways between neoplastic stem cells and healthy stem cells could be identified. In this review, we present the evidence which links the signals emanating from the PI3K/Akt/mTOR cascade with the functions of cancer stem cells, both in solid and hematological tumors. We then highlight how targeting PI3K/Akt/mTOR signaling with small molecules could improve cancer patient outcome.
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Affiliation(s)
- Alberto M. Martelli
- Department of Human Anatomy, University of Bologna, via Irnerio 48, 40126 Bologna, Italy; E-Mails: (C.E.); (F.C.); (C.G.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +39-051-2091580; Fax: +39-051-2091695
| | - Camilla Evangelisti
- Department of Human Anatomy, University of Bologna, via Irnerio 48, 40126 Bologna, Italy; E-Mails: (C.E.); (F.C.); (C.G.)
| | - Francesca Chiarini
- Department of Human Anatomy, University of Bologna, via Irnerio 48, 40126 Bologna, Italy; E-Mails: (C.E.); (F.C.); (C.G.)
| | - Cecilia Grimaldi
- Department of Human Anatomy, University of Bologna, via Irnerio 48, 40126 Bologna, Italy; E-Mails: (C.E.); (F.C.); (C.G.)
| | - James A. McCubrey
- Department of Microbiology & Immunology, Brody School of Medicine, East Carolina University, 600 Moye Boulevard, NC 27834, USA; E-Mail: (J.A.M.)
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