Here, we describe protocols for the genetic and chemical validation of c-Fos and Dusp1 as a drug target in leukemia using in vitro and in vivo genetic and humanized mouse models. This method can be applied to any target for genetic validation and therapeutic development.
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Method Article
Methods for Evaluating the Role of c-Fos and Dusp1 in Oncogene Dependence
In This Article
Summary
Abstract
The demonstration of tyrosine kinase inhibitors (TKIs) in treating chronic myeloid leukemia (CML) has heralded a new era in cancer therapeutics. However, a small population of cells does not respond to TKI treatment, resulting in minimal residual disease (MRD); even the most potent TKIs fail to eradicate these cells. These MRD cells serve as a reservoir to develop resistance to therapy. Why TKI treatment is ineffective against MRD cells is not known. Growth factor signaling is implicated in supporting the survival of MRD cells during TKI treatment, but a mechanistic understanding is lacking. Recent studies demonstrated that an elevated c-Fos and Dusp1 expression as a result of convergent oncogenic and growth factor signaling in MRD cells mediate TKI resistance. The genetic and chemical inhibition of c-Fos and Dusp1 renders CML exquisitely sensitive to TKIs and cures CML in both genetic and humanized mouse models. We identified these target genes using multiple microarrays from TKI-sensitive and -resistant cells. Here, we provide methods for target validation using in vitro and in vivo mouse models. These methods can easily be applied to any target for genetic validation and therapeutic development.
Introduction
Constitutive tyrosine kinase activity of BCR-ABL1 fusion oncogene causes CML, which provides a rationale to target the kinase activity by small molecule inhibitors. The success of TKIs in treating CML patients revolutionized the concept of targeted therapy1,2. Subsequently, anti-kinase therapy as precision medicine was developed for several other malignancies, including solid tumors. So far, more than thirty kinase inhibitors have been approved by the United State FDA for treating various malignancies. While TKI treatment is very effective in suppressing the disease, it is not curative. Besides, a small popula....
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Protocol
All animal experiments were carried out according to the guidelines of the Institutional Animal Care and Use Committee (IACUC) at Cincinnati Children's Hospital Medical Center (CCHMC). Human specimens (Normal BM and that from CML (p210-BCR-ABL+) leukemia) were obtained through Institutional Review Board-approved protocols (Institutional Review Board: Federalwide Assurance #00002988 Cincinnati Children's Hospital Medical Center) and donor-informed consent from CCHMC and the University of Cincinnati.
1. Real-time qPCR Analysis
- Isolate total RNA from BaF3 cells growing in RPMI supplemented with 10% FBS and 10% WEHI spent cu....
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Results
Oncogene addiction has been implicated in the therapeutic efficacy of TKIs. However, the mechanisms driving the oncogene dependence are not understood. We performed multiple unbiased gene expression analyses to identify the genetic component involved in orchestrating the addiction. These analyses revealed the upregulation of three genes, c-Fos, Dusp1, and Zfp36, in cancer cells that are not dependent on oncogenic signaling for survival and, thus, are insensitive to TKI treatment. The down.......
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Discussion
For the bulk of cancer cells, the therapeutic response to TKI is mediated by a blockade of tyrosine-kinase-oncoprotein signals to which the tumor is addicted. However, relatively little is known about how a minority of cancer cells contributing to MRD escape the oncogene dependence and therapy4. Recent studies revealed that growth factor signaling mediates drug resistance in both leukemia and solid organ tumors. This suggests that various molecular mechanisms might underlie intrinsic resistance
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Disclosures
The authors have nothing to disclose.
Acknowledgements
The authors are thankful to G. Q. Daley for providing the BaF3 and WEHI cells and T. Reya for the MSCV-BCR-ABL-Ires-YFP constructs. The authors are thankful to M. Carroll for providing the patient samples from the CML blast crisis. This study was supported by grants to M.A. from the NCI (1RO1CA155091), the Leukemia Research Foundation and V Foundation, and from the NHLBI (R21HL114074-01).
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Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| Biological Materials | |||
| RPMI | Cellgro (corning) | 15-040-CV | |
| DMEM | Cellgro (corning) | 15-013-CV | |
| IMDM | Cellgro (corning) | 15-016-CVR | |
| RetroNectin Recombinant Human Fibronectin Fragment | Takara | T100B | |
| MethoCult GF M3434 (Methylcellulose for Mouse CFU) | Stem Cell | 3434 | |
| MethoCult H4434 Classic (Methylcellulose for Human CFU) | Stem Cell | 4434 | |
| 4-Hydroxytamoxifen | Sigma | H6278 | |
| Recombinant Murine SCF | Prospec | CYT-275 | |
| Recombinant Murine Flt3-Ligand | Prospec | CYT-340 | |
| Recombinant Murine IL-6 | Prospec | CYT-350 | |
| Recombinant Murine IL-7 | Peprotech | 217-17 | |
| DFC | LKT Laboratories Inc. | D3420 | |
| BCI | Chemzon Scientific | NZ-06-195 | |
| Imatinib | LC Laboratory | I-5508 | |
| Curcumin | Sigma | 458-37-7 | |
| NDGA | Sigma | 500-38-9 | |
| Penn/Strep | Cellgro (corning) | 30-002-CI | |
| FBS | Atlanta biological | S11150 | |
| Trypsin EDTA 1x | Cellgro (corning) | 25-052-CI | |
| 1x PBS | Cellgro (corning) | 21-040-CV | |
| L-Glutamine | Cellgro (corning) | 25-005-CL | 5 mg/mL stock in water |
| Puromycin | Gibco (life technologies) | A11138-03 | |
| HEPES | Sigma | H7006 | |
| Na2HPO4.7H2O | Sigma | S9390 | |
| Protamine sulfate | Sigma | P3369 | 5 mg/mL stock in water |
| Trypan Blue solution (0.4%) | Sigma | T8154 | |
| DMSO | Cellgro (corning) | 25-950-CQC | |
| WST-1 | Roche | 11644807001 | |
| 0.45 μM acro disc filter | PALL | 2016-10 | |
| 70 μm nylon cell stariner | Becton Dickinson | 352350 | |
| FICOL (Histopaque 1083) (polysucrose) | Simga | 1083 | |
| PBS | Corning | 21040CV | |
| LS Columns | Miltenyi | 130-042-401 | |
| Protease Inhibitor Cocktail | Roche | CO-RO | |
| Phosphatase Inhibitor Cocktail 2 | Sigma | P5762 | |
| Nitrocullulose Membrane | Bio-Rad | 1620115 | |
| SuperSignal West Dura Extended Duration Substrate ( chemiluminiscence substrate) | Thermo Scientific | 34075 | |
| CD5 | eBioscience | 13-0051-82 | |
| CD11b | eBioscience | 13-0112-75 | |
| CD45R (B220) | BD biosciences | 553092 | |
| CD45.1-FITC | eBioscience | 11-0453-85 | |
| CD45.2-PE | eBioscience | 12-0454-83 | |
| hCD45-FITC | BD Biosciences | 555482 | |
| Anti-Biotin-FITC | Miltenyi | 130-090-857 | |
| Anti-7-4 | eBioscience | MA5-16539 | |
| Anti-Gr-1 (Ly-6G/c) | eBioscience | 13-5931-82 | |
| Anti-Ter-119 | eBioscience | 13-5921-75 | |
| Ly-6 A/E (Sca1) PE Cy7 | BD | 558612 | |
| CD117 APC | BD | 553356 | |
| BD Pharm Lyse | BD | 555899 | |
| BD Cytofix/Cytoperm (Fixing and permeabilization solution) | BD | 554714 | |
| BD Perm/Wash (permeabilization and wash solution for phospho flow) | BD | 554723 | |
| phospho p38 | Cell Signaling Technologies | 4511S | |
| total p38 | Cell Signaling Technologies | 9212 | |
| Mouse IgG control | BD | 554121 | |
| Alexa Flour 488 conjugated | Invitrogen | A-11034 | |
| Calcium Chloride | Invitrogen | K278001 | |
| 2x HBS | Invitrogen | K278002 | |
| EDTA | Ambion | AM9261 | |
| BSA | Sigma | A7906 | |
| Blood Capillary Tubes | Fisher | 22-260-950 | |
| Blood Collection Tube | Giene Bio-One | 450480 | |
| Newborn Calf Serum | Atlanta biological | S11295 | |
| Erythropoiein | Amgen | 5513-267-10 | |
| human SCF | Prospec | CYT-255 | |
| Human IL-3 | Prospec | CYT-210 | |
| G-SCF | Prospec | CYT-220 | |
| GM-CSF | Prospec | CYT-221 | |
| MyeloCult (media for LTCIC assay) | Stem Cell Technologies | 5100 | |
| Hydrocortisone Sodium Hemisuccinate | Stem Cell Technologies | 7904 | |
| MEM alpha | Gibco | 12561-056 | |
| 1/2 cc Lo-Dose u-100 insulin syringe 28 G1/2 | Becton Dickinson | 329461 | |
| Mortor pestle | Coor tek | 60316 and 60317 | |
| Isoflorane (Isothesia TM) | Butler Schien | 29405 | |
| SOC | New England Biolabs | B90920s | |
| Ampicillin | Sigma | A0166 | 100 mg/mL stock in water |
| Bacto agar (agar) | Difco | 214050 | |
| Terrific broth | Becton Dickinson | 243820 | |
| Agarose | Genemate | E-3119-500 | |
| Doxycycline chow | TestDiet.com | 52662 | modified RMH1500, Autoclavable 5LK8 with 0.0625% Doxycycline |
| Tamoxifen | Sigma | T5648 | |
| Iodonitrotetrazolium chloride | Sigma | I10406 | |
| Kits | |||
| Dneasy Blood & tissue kit | Qiagen | 69506 | |
| GoTaq Green (taq polymerase with Green loadign dye) | Promega | M1722 | |
| miRNeasy Mini Kit (RNA isolation kit) | Qiagen | 217084 | |
| DNA Free Dnase Kit (DNAse treatment for RT PCR) | Ambion, Life Technologies | AM1906 | |
| Superscript III First Strand Synthesis (reverse transcriptase for cDNA synthesis) | Invitrogen | 18080051 | |
| SYBR Green (taq polymerase mix with green interchalating dye for qPCR) | Bio-Rad | 1725270 | |
| CD117 MicroBead Kit | Miltenyi | 130-091-224 | |
| Human Long-Term Culture Initiating Cell Assay | Stemp Cell Technologies | ||
| Instruments | |||
| NAPCO series 8000 WJ CO2 incubator | Thermo scientific | ||
| Swing bucket rotor cetrifuge 5810R | Eppendorf | ||
| TC-10 automated cell counter | Bio-RAD | ||
| C-1000 Thermal cycler | Bio-RAD | ||
| Mastercycler Real Plex 2 | Eppendorf | ||
| ChemiDoc Imaging System (imaging system for gels and western blots) | Bio-RAD | 17001401 | |
| Hemavet (boold counter) | Drew-Scientific | ||
| LSR II (FACS analyzer) | BD | ||
| Fortessa I (FACS analyzer) | BD | ||
| FACSAriaII (FACS Sorter) | BD | ||
| Magnet Stand | Miltenyi | ||
| Irradiator | J.L. Shepherd and Associates, San Fernando CA | Mark I Model 68A | source Cs 137 |
| Mice | |||
| ROSACreERT2 | Jackson Laboratory | ||
| Scl-tTA | Dr. Claudia Huettner’s lab | ||
| BoyJ | mouse core facility at CCHMC | ||
| C57Bl/6 | Jackson Laboratory | ||
| NSGS | mouse core facility at CCHMC | ||
| ROSACreERT2/c-Fosfl/fl Dusp1-/- | Made in house | ||
| ROSACreERT2/c-Fosfl/fl | Made in house | ||
| Cells | |||
| BaF3 | Gift from George Daley, Harvard Medical School, Boston | ||
| WEHI | Gift from George Daley, Harvard Medical School, Boston | ||
| CML-CD34+ and Normal CD34+ cells | University Hospital, University of Cincinnati |
References
- Daley, G. Q., Van Etten, R. A., Baltimore, D. Induction of chronic myelogenous leukemia in mice by the P210bcr/abl gene of the Philadelphia chromosome. Science. 247, 824-830 (1990).
- Druker, B. J., et al. E....
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