| 1. |
- Bonagas, Nadilly, et al.
(författare)
-
Pharmacological targeting of MTHFD2 suppresses acute myeloid leukemia by inducing thymidine depletion and replication stress
- 2022
-
Ingår i: NATURE CANCER. - : Springer Science and Business Media LLC. - 2662-1347. ; 3:2, s. 156-
-
Tidskriftsartikel (refereegranskat)abstract
- The folate metabolism enzyme MTHFD2 (methylenetetrahydrofolate dehydrogenase/cyclohydrolase) is consistently overexpressed in cancer but its roles are not fully characterized, and current candidate inhibitors have limited potency for clinical development. In the present study, we demonstrate a role for MTHFD2 in DNA replication and genomic stability in cancer cells, and perform a drug screen to identify potent and selective nanomolar MTHFD2 inhibitors; protein cocrystal structures demonstrated binding to the active site of MTHFD2 and target engagement. MTHFD2 inhibitors reduced replication fork speed and induced replication stress followed by S-phase arrest and apoptosis of acute myeloid leukemia cells in vitro and in vivo, with a therapeutic window spanning four orders of magnitude compared with nontumorigenic cells. Mechanistically, MTHFD2 inhibitors prevented thymidine production leading to misincorporation of uracil into DNA and replication stress. Overall, these results demonstrate a functional link between MTHFD2-dependent cancer metabolism and replication stress that can be exploited therapeutically with this new class of inhibitors. Helleday and colleagues describe a nanomolar MTHFD2 inhibitor that causes replication stress and DNA damage accumulation in cancer cells via thymidine depletion, demonstrating a potential therapeutic strategy in AML tumors in vivo.
|
|
| 2. |
- Bonagas Villarreal, Nadilly Y
(författare)
-
Exploring novel roles of metabolic enzymes MTHFD2 and PFKFB3 in cancer genome stability and their potential as anticancer therapeutic targets
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Altered tumor metabolism has been described as early as the 1920s, but it was only in recent decades that proteomic and metabolomic studies revealed that the ways in which tumors rewire their nutrient and energy pathways are more diverse and have more implications for treatment outcome than previously thought. There is now a great interest in characterizing promising metabolic targets and identifying novel ways by which to exploit them for cancer treatment. This thesis work is part of an ongoing effort to elucidate the molecular mechanisms behind metabolic cancer targets specifically at the interface of genome stability, their role in the pathogenesis of different tumor types and genetic contexts, and their suitability as drug targets for clinically relevant treatment strategies. In Paper I, we present a new role for the glycolysis enzyme 6-phosphofructo 2-kinase/fructose 2,6-bisphosphatase 3 (PFKFB3) in homologous recombination (HR). We used gene silencing and pharmacological inhibitors to investigate the role of PFKFB3 in the response to DNA damage induced by ionizing radiation (IR). We found that PFKFB3 promotes the recruitment of DNA repair factors and supplies nucleotides for DNA synthesis through its interaction with ribonucleotide reductase (RNR). We also validated the antitumor preclinical potential of PFKFB3 inhibitor KAN0438757 and showed it specifically sensitized cancer cells to IR. In Paper II, we solve the first crystal structure of human one-carbon metabolism enzyme methylenetetrahydrofolate dehydrogenase 2, methenyltetrahydrofolate cyclohydrolase (MTHFD2) in complex with its cofactors and a weak inhibitor, LY345899. We developed biochemical activity and target engagement assays to evaluate the binding and inhibition of MTHFD2 by LY345899 in cancer cell models. With the newfound structural insights to determine key residues important for substrate and cofactor binding, we were able to undertake a structure-based drug discovery program targeting MTHFD2 detailed in Paper III. Paper III expands on the groundwork laid out in Paper II to develop first-in-class, highly potent and cell active inhibitors of MTHFD2 (MTHFD2i). Again, using gene silencing techniques, we identified a novel role for MTHFD2 in genome maintenance, which we confirmed with our small molecule inhibitors. We show that MTHFD2i induce replication stress and apoptosis selectively in transformed cells as a result of impaired de novo thymidylate synthesis and genomic uracil misincorporation. We established an in vivo model of acute myeloid leukemia (AML) and showed that MTHFD2i significantly prolonged survival and outperformed the standard of care compound cytarabine (AraC), providing proof-of-concept for the translational potential of MTHFD2i as anticancer drugs. In Paper IV, we further elaborate on the role of MTHFD2 in genome maintenance in response to DNA damage. We found that MTHFD2 accumulates and associates to chromatin upon DNA double strand breaks (DSBs) and promotes DNA repair through HR. Loss of MTHFD2 significantly impairs HR activity, with MTHFD2i specifically sensitizing cancer cells to PARP inhibitors in vitro and delaying tumor growth when combined with a PARP inhibitor in vivo. Taken together, these studies showcase these two metabolic enzymes, PFKFB3 and MTHFD2, in a new light as novel DNA damage response (DDR) targets. Our findings provide compelling evidence to propose the intersection of cancer metabolism and genome stability as an untapped source of novel anticancer targets warranting more mechanistic and drug development efforts.
|
|
| 3. |
- Green, Alanna C., et al.
(författare)
-
Formate overflow drives toxic folate trapping in MTHFD1 inhibited cancer cells
- 2023
-
Ingår i: Nature Metabolism. - : Springer Nature. - 2522-5812. ; 5:4, s. 642-659
-
Tidskriftsartikel (refereegranskat)abstract
- Cancer cells fuel their increased need for nucleotide supply by upregulating one-carbon (1C) metabolism, including the enzymes methylenetetrahydrofolate dehydrogenase–cyclohydrolase 1 and 2 (MTHFD1 and MTHFD2). TH9619 is a potent inhibitor of dehydrogenase and cyclohydrolase activities in both MTHFD1 and MTHFD2, and selectively kills cancer cells. Here, we reveal that, in cells, TH9619 targets nuclear MTHFD2 but does not inhibit mitochondrial MTHFD2. Hence, overflow of formate from mitochondria continues in the presence of TH9619. TH9619 inhibits the activity of MTHFD1 occurring downstream of mitochondrial formate release, leading to the accumulation of 10-formyl-tetrahydrofolate, which we term a ‘folate trap’. This results in thymidylate depletion and death of MTHFD2-expressing cancer cells. This previously uncharacterized folate trapping mechanism is exacerbated by physiological hypoxanthine levels that block the de novo purine synthesis pathway, and additionally prevent 10-formyl-tetrahydrofolate consumption for purine synthesis. The folate trapping mechanism described here for TH9619 differs from other MTHFD1/2 inhibitors and antifolates. Thus, our findings uncover an approach to attack cancer and reveal a regulatory mechanism in 1C metabolism.
|
|
| 4. |
- Gustafsson, Nina M. S., et al.
(författare)
-
Targeting PFKFB3 radiosensitizes cancer cells and suppresses homologous recombination
- 2018
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- The glycolytic PFKFB3 enzyme is widely overexpressed in cancer cells and an emerging anticancer target. Here, we identify PFKFB3 as a critical factor in homologous recombination (HR) repair of DNA double-strand breaks. PFKFB3 rapidly relocates into ionizing radiation (IR)-induced nuclear foci in an MRN-ATM-gamma H2AX-MDC1-dependent manner and co-localizes with DNA damage and HR repair proteins. PFKFB3 relocalization is critical for recruitment of HR proteins, HR activity, and cell survival upon IR. We develop KAN0438757, a small molecule inhibitor that potently targets PFKFB3. Pharmacological PFKFB3 inhibition impairs recruitment of ribonucleotide reductase M2 and deoxynucleotide incorporation upon DNA repair, and reduces dNTP levels. Importantly, KAN0438757 induces radiosensitization in transformed cells while leaving non-transformed cells unaffected. In summary, we identify a key role for PFKFB3 enzymatic activity in HR repair and present KAN0438757, a selective PFKFB3 inhibitor that could potentially be used as a strategy for the treatment of cancer.
|
|
| 5. |
- Gustafsson, Robert, et al.
(författare)
-
Crystal Structure of the Emerging Cancer Target MTHFD2 in Complex with a Substrate-Based Inhibitor
- 2017
-
Ingår i: Cancer Research. - : AMER ASSOC CANCER RESEARCH. - 0008-5472 .- 1538-7445. ; 77:4, s. 937-948
-
Tidskriftsartikel (refereegranskat)abstract
- To sustain their proliferation, cancer cells become dependent on one-carbon metabolism to support purine and thymidylate synthesis. Indeed, one of the most highly upregulated enzymes during neoplastic transformation is MTHFD2, a mitochondrial methylenetetrahydrofolate dehydrogenase and cyclohydrolase involved in one-carbon metabolism. Because MTHFD2 is expressed normally only during embryonic development, it offers a disease-selective therapeutic target for eradicating cancer cells while sparing healthy cells. Here we report the synthesis and preclinical characterization of the first inhibitor of human MTHFD2. We also disclose the first crystal structure of MTHFD2 in complex with a substrate-based inhibitor and the enzyme cofactors NAD(+) and inorganic phosphate. Our work provides a rationale for continued development of a structural framework for the generation of potent and selective MTHFD2 inhibitors for cancer treatment.
|
|
