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408 The Mevalonate Pathway Is a Therapeutic Target in TP53 Mutant Acute Myeloid Leukemia

Program: Oral and Poster Abstracts
Type: Oral
Session: 602. Myeloid Oncogenesis: Basic: Therapeutic Strategies and Cellular Mechanisms
Hematology Disease Topics & Pathways:
Fundamental Science, Acute Myeloid Malignancies, Research, AML, Translational Research, Combination therapy, Diseases, Therapies, metabolism, Biological Processes, Myeloid Malignancies, molecular biology
Sunday, December 10, 2023: 10:45 AM

Sarah Skuli, MD, PhD1, A'Ishah Bakayoko, BA1*, Gerald Wertheim, MD, PhD1,2*, Owen Riley1*, Marisa Kruidenier, BA1*, Bryan Manning, BS1*, Akmal Salimov, BA1*, Gisela Brake-Silla, MS1*, Derek Dopkin, BA1*, Jimmy Xu, PhD3*, Eva Nee3*, Lorelai Mesaros3*, Ryan Hausler, MS1*, Manuela Lavorato, PhD4*, Eiko Ogiso, PhD4*, Marni Falk, MD4*, Kara Maxwell, MD, PhD1*, Nicolas Skuli, PhD1*, Clementina Mesaros, PhD3* and Martin Carroll, MD1

1Division of Hematology/Oncology, Department of Medicine, The Perelman School of Medicine at The University of Pennsylvania, Philadelphia, PA
2Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA
3Department of Pharmacology, The University of Pennsylvania, Philadelphia, PA
4Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA


Acute myeloid leukemia (AML) with mutations in the TP53 tumor suppressor gene is the most fatal of AMLs with a median overall survival of only six months due to chemotherapy resistance. To understand biologic differences in TP53 mutant (MT) AML, as compared to wildtype (WT) AML, we performed transcriptomic analysis on sorted patient samples. Gene set enrichment analysis demonstrated significant upregulation of the cholesterol biosynthesis or mevalonate pathway in TP53 MT AML. In TP53 MT solid tumor models, the mevalonate pathway plays a key role in tumorigenesis and metastasis. We hypothesized that the mevalonate pathway is essential for chemotherapy resistance of TP53 MT AML and represents a novel therapeutic target.


We developed chemoresistant, isogenic TP53 MT AML cell lines using CRISPR/Cas9 technology in the MOLM14 AML cell line. We used primary TP53 MT AML patient samples to perform colony forming unit (CFU) assays, in vitro assays with a serum substitute and cytokines, and a patient derived xenograft (PDX) model of TP53 MT AML.


We first sought to determine if TP53 MT AML exhibits upregulation of mevalonate pathway activity in response to cytarabine (AraC), the backbone of AML therapy. We treated our isogenic TP53 MT AML cell lines for 24 hours (h) with AraC and assessed mevalonate pathway gene expression and metabolites using qRT-PCR and liquid chromatography high resolution mass spectrometry (LC-HRMS), respectively. Only TP53 MT cell lines respond to AraC with a significant upregulation of key mevalonate pathway genes and metabolites.

We then determined if TP53 MT AML is sensitized to AraC by inhibition of the mevalonate pathway with a statin. We pretreated our isogenic cell lines with 24h rosuvastatin before 24h AraC and assessed cell viability with flow cytometry with AnnexinV/7AAD staining and XTT assays. We also performed CFU assays in TP53 MT AML patient samples treated with the two drugs alone or in combination and assessed CFUs after 14 days. These studies revealed a synergistic reduction in cell viability and CFUs in TP53 MT AML by rosuvastatin in combination with AraC.

We next addressed the mechanism by which a statin sensitizes TP53 MT AML to AraC. Our group and others have demonstrated enhanced mitochondrial activity is associated with AML chemoresistance. We hypothesized that mevalonate pathway byproducts, known to be crucial for mitochondrial functions, contribute to the mitochondrial response to AraC. We treated TP53 MT AML cell lines as above with rosuvastatin and AraC and used seahorse technology to measure oxidative phosphorylation (OXPHOS). We also used electron microscopy, flow cytometry of mitochondrial protein, TOM20, and qRT-PCR for mitochondrial DNA content to quantify and characterize mitochondria. These data demonstrate that TP53 MT AML cell lines, compared to WT, exhibit a significant increase in OXPHOS after 24h that is due to an increase in total mitochondrial. These effects are abrogated by pretreatment with a statin. We also validated these findings in primary TP53 MT AML patient samples in vitro. Importantly, co-treatment of the isogenic TP53 MT AML cell lines with a soluble form of mevalonate or a downstream byproduct, geranylgeranyl pyrophosphate (GGPP), recovered OXPHOS and subsequent chemoresistance. Overall, this data supports a model where TP53 MT AML cells dynamically upregulate the mevalonate pathway to regulate OXPHOS and avoid DNA damage-induced cell death (Figure 1).

Finally, we studied a PDX model of TP53 MT AML. Engrafted mice were treated with AraC for five days alone or in combination with high dose rosuvastatin. Mice were harvested on day eight with assessment of leukemic burden by flow, OXPHOS by seahorse and mevalonate byproducts by LC-HRMS. TP53 MT AML leukemic burden was only significantly reduced by the combination therapy. Consistent with in vitro findings, mice sacrificed three days after completing AraC continue to demonstrate enhanced OXPHOS and increased mevalonate byproducts. This response is blunted by rosuvastatin.


These results demonstrate that TP53 MT AML requires the mevalonate pathway for chemotherapy resistance and targeting of this pathway in combination with chemotherapy may improve clinical responses. Analysis is ongoing to determine the role of GGPP in regulating the mitochondrial response to DNA damage in TP53 MT cells in order to elucidate novel therapeutic approaches.

Disclosures: Carroll: Janssen Pharmaceuticals: Consultancy; Cartography Bioscences: Membership on an entity's Board of Directors or advisory committees.

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