An enolase inhibitor for the targeted treatment of ENO1-deleted cancers

https://openworks.mdanderson.org/sumexp21/1197/thumbnail.jp

An In Vivo Screen Identifies PYGO2 as a Driver for Metastatic Prostate Cancer

Advanced prostate cancer displays conspicuous chromosomal instability and rampant copy number aberrations, yet the identity of functional drivers resident in many amplicons remain elusive. Here, we implemented a functional genomics approach to identify new oncogenes involved in prostate cancer progression. Through integrated analyses of focal amplicons in large prostate cancer genomic and transcriptomic datasets as well as genes upregulated in metastasis, 276 putative oncogenes were enlisted into an in vivo gain-of-function tumorigenesis screen. Among the top positive hits, we conducted an in-depth functional analysis on Pygopus family PHD finger 2 (PYGO2), located in the amplicon at 1q21.3. PYGO2 overexpression enhances primary tumor growth and local invasion to draining lymph nodes. Conversely, PYGO2 depletion inhibits prostate cancer cell invasion in vitro and progression of primary tumor and metastasis in vivo In clinical samples, PYGO2 upregulation associated with higher Gleason score and metastasis to lymph nodes and bone. Silencing PYGO2 expression in patient-derived xenograft models impairs tumor progression. Finally, PYGO2 is necessary to enhance the transcriptional activation in response to ligand-induced Wnt/β-catenin signaling. Together, our results indicate that PYGO2 functions as a driver oncogene in the 1q21.3 amplicon and may serve as a potential prognostic biomarker and therapeutic target for metastatic prostate cancer.Significance: Amplification/overexpression of PYGO2 may serve as a biomarker for prostate cancer progression and metastasis. Cancer Res; 78(14); 3823-33. ©2018 AACR

Prodrugs of a 1-Hydroxy-2-Oxopiperidin-3-Yl Phosphonate Enolase Inhibitor for the Treatment of ENO1-Deleted Cancers

Cancers harboring homozygous deletion of the glycolytic enzyme enolase 1 (ENO1) are selectively vulnerable to inhibition of the paralogous isoform, enolase 2 (ENO2). A previous work described the sustained tumor regression activities of a substrate-competitive phosphonate inhibitor of ENO2, 1-hydroxy-2-oxopiperidin-3-yl phosphonate (HEX) (5), and its bis-pivaloyoxymethyl prodrug, POMHEX (6), in an ENO1-deleted intracranial orthotopic xenograft model of glioblastoma [Nature Metabolism 2020, 2, 1423-1426]. Due to poor pharmacokinetics of bis-ester prodrugs, this study was undertaken to identify potential non-esterase prodrugs for further development. Whereas phosphonoamidate esters were efficiently bioactivated in ENO1-deleted glioma cells, McGuigan prodrugs were not. Other strategies, including cycloSal and lipid prodrugs of 5, exhibited low micromolar IC50 values in ENO1-deleted glioma cells and improved stability in human serum over 6. The activity of select prodrugs was also probed using the NCI-60 cell line screen, supporting its use to examine the relationship between prodrugs and cell line-dependent bioactivation

Homozygous MTAP deletion in primary human glioblastoma is not associated with elevation of methylthioadenosine.

Homozygous deletion of methylthioadenosine phosphorylase (MTAP) in cancers such as glioblastoma represents a potentially targetable vulnerability. Homozygous MTAP-deleted cell lines in culture show elevation of MTAP\u27s substrate metabolite, methylthioadenosine (MTA). High levels of MTA inhibit protein arginine methyltransferase 5 (PRMT5), which sensitizes MTAP-deleted cells to PRMT5 and methionine adenosyltransferase 2A (MAT2A) inhibition. While this concept has been extensively corroborated in vitro, the clinical relevance relies on exhibiting significant MTA accumulation in human glioblastoma. In this work, using comprehensive metabolomic profiling, we show that MTA secreted by MTAP-deleted cells in vitro results in high levels of extracellular MTA. We further demonstrate that homozygous MTAP-deleted primary glioblastoma tumors do not significantly accumulate MTA in vivo due to metabolism of MTA by MTAP-expressing stroma. These findings highlight metabolic discrepancies between in vitro models and primary human tumors that must be considered when developing strategies for precision therapies targeting glioblastoma with homozygous MTAP deletion

The TCA cycle as a nexus of metabolic vulnerabilities in cancer

Uncontrolled proliferation of cancer cells necessitates rewiring of metabolic pathways to meet biosynthetic and bioenergetic demands of proliferation and fortify redox homeostasis. An increasing body of literature suggests that mitochondrial metabolism (tricarboxylic acid cycle (TCA) and oxidative phosphorylation) is imperative for cancer cell growth and proliferation. The scope of the works presented in this dissertation is to explore the importance of mitochondrial metabolism, and primarily the TCA cycle—the anabolic factory of cancer cells and leverage it as a targetable vulnerability in cancer. Cancer cells consume anabolic nutrients that are used to generate biosynthetic precursors in the TCA cycle. Continuous efflux of carbon atoms from the TCA cycle for biosynthetic and catabolic oxidative reactions requires carbon atoms to be replenished by a process called anaplerosis. The work in this thesis shows that impinging on TCA cycle anaplerosis, either by impairing the breakdown of nutrients (glycolysis/glutaminolysis inhibition), or by restricting the import of blood-borne nutrients (angiogenesis inhibition), or by targeting coenzyme biosynthesis (acetyl-CoA for TCA cycle), can selectively impair cancer cell viability in vitro and in intracranial growth of tumors in vivo. Collectively, the work described herein establishes the TCA cycle as a promising targetable vulnerability in cancer

Re-evaluating the mechanism of histone lactylation

Recent work by Zhang et al. published in Nature identified a unique non-metabolic role of the glycolysis end-product lactate, in post-translational lactylation of histones. The original study as well as follow-up editorials allude that lactate after being activated as lactyl-CoA mediates histone lactylation. Review of the experiments performed and the controls employed in the original study raises doubts on the proposed source and mechanism of lactylation. Herein, guided by findings from multiple labs including metabolomic studies from our own, we argue that S-lactoyl-glutathione is a more plausible substrate for histone lactylation

Generation and Validation of an Anti-Human PANK3 Mouse Monoclonal Antibody

Coenzyme A (CoA) is an essential co-factor at the intersection of diverse metabolic pathways. Cellular CoA biosynthesis is regulated at the first committed step—phosphorylation of pantothenic acid—catalyzed by pantothenate kinases (PANK1,2,3 in humans, PANK3 being the most highly expressed). Despite the critical importance of CoA in metabolism, the differential roles of PANK isoforms remain poorly understood. Our investigations of PANK proteins as potential precision oncology collateral lethality targets (PANK1 is co-deleted as part of the PTEN locus in some highly aggressive cancers) were severely hindered by a dearth of commercial antibodies that can reliably detect endogenous PANK3 protein. While we successfully validated commercial antibodies for PANK1 and PANK2 using CRISPR knockout cell lines, we found no commercial antibody that could detect endogenous PANK3. We therefore set out to generate a mouse monoclonal antibody against human PANK3 protein. We demonstrate that a clone (Clone MDA-299-62A) can reliably detect endogenous PANK3 protein in cancer cell lines, with band-specificity confirmed by CRISPR PANK3 knockout and knockdown cell lines. Sub-cellular fractionation shows that PANK3 is overwhelmingly cytosolic and expressed broadly across cancer cell lines. PANK3 monoclonal antibody MDA-299-62A should prove a valuable tool for researchers investigating this understudied family of metabolic enzymes in health and disease