Biology subjects

Ronayne, C. T.

Publications and source records attributed to Ronayne, C. T..

6 recordsLinked to original sources

bioRxiv2025

Targeting tumor antioxidant pathways with novel GSTP1/M2 inhibitors for cancer treatment

Glutathione transferase (GSTP1 and GSTM2) are tractable targets for anticancer drug development. In this work, a series of 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol (NBDHEX) based analogues were designed, synthesized, and evaluated both theoretically and experimentally as GSTP1 and GSTM2 inhibitors. Among the synthesized compounds, 3h showed selective inhibition toward GSTP1 while 5b showed selective inhibition of GSTM2. Compounds 5b and 5c exhibited stronger potency while compound 3h showed slightly lower potency against the tested cancer cells than its parent molecule NBDHEX. Comprehensive biological studies were conducted on the effect of 3h, 5b and 5c towards breast cancer MDA-MB-231 and pancreatic MiaPaCa-2 cell lines revealed that 3h, 5b and 5c could activate JNK pathway and induce cell apoptosis. Furthermore in vivo experiments using NSG mice demonstrated that 5b significantly reduced tumor growth when administered in combination with gemcitabine, effectively overcoming gemcitabine resistance in the MiaPaCa-2 cell model through targeted inhibition of GSTM2. These findings suggests that, 5b could become a promising candidate for further development as a potential antitumor agent in cancer therapy.

cancer biology↗

bioRxiv2025

Nitroxoline-O-protected derivatives inhibit MetAP2 and activate ATF4 through mTORC1 to inhibit cancer cell growth

Reprogrammed cancer cell proliferation requires high levels of protein synthesis and concomitant folding and processing. N-terminal methionine amino peptidases (MetAP) are a class of enzymes that cleave the initiator methionine amino acids to allow for peptide maturation and co-translational processing. Specifically, based on its role in protein synthesis, MetAP2 has been found to be upregulated in cancer cells and has been explored as a potential anticancer target. Cellular perturbations that impinge on protein synthesis activate cellular stress pathways, including the integrated stress response and mTORC1. Nitroxoline, a MetAP2 inhibitor has been explored as an anticancer agent but is hampered by poor pharmacokinetic properties. Here, we synthesize a few O-substituted silyl and nonsilyl nitroxoline analogs to diversify the nitroxoline template to reduce metabolic vulnerability. In vitro MetAP2 and cancer cell proliferation inhibition assays demonstrate that synthesized analogs retain potency when compared to the parent nitroxoline. Mechanistically, we show that the lead candidate compound 3 and nitroxoline activate ATF4 mediated stress responses through non-canonical mTORC1. These results further implicate MetAP2 protein processing in mTORC1 nutrient sensing pathways and provide novel synthetic analogs of nitroxoline for potential cancer treatment.

cancer biology↗

bioRxiv2025

Synthesis and biological evaluation of glutathione-responsive 2-alkoxycarbonyl allyl niclosamide prodrugs as anticancer agents

Reprogrammed mitochondrial metabolism is recognized as an important target for anticancer therapy. Niclosamide, an FDA approved anthelmintic agent with mitochondrial uncoupling activity, has shown promise as an anticancer agent. However, off target mitochondrial toxicity has rendered the utility of this agent at clinically effective doses. Here, we synthesize a variety of prodrugs on the niclosamide template based on the Baylis-Hillman (BH) reaction, with the hypothesis that niclosamide will be released upon the reaction with cellular nucleophiles, including thiols. Consistent with this hypothesis, the BH-prodrugs release the parent niclosamide in the presence of cysteine and glutathione, and the cancer cell proliferation inhibition properties of the lead candidates are retained when compared to the parent niclosamide. Mitochondrial respiration assays illustrate that niclosamide acutely uncouples the mitochondria, and the lead BH-prodrug 6b does not, providing evidence of this prodrug strategy in mitigating off target toxicities. In a dose escalation study, the lead candidate 6b is generally well tolerated in healthy mice as evidenced by zero mortality, normal grooming pattern, and normal weight gains. Finally, 6b exhibits 54% volume tumor growth inhibition properties in a syngraft model of breast cancer in mice. The studies herein provide a novel methodology for the application of BH prodrugs on the niclosamide template and the anticancer applications.

pharmacology and toxicology↗

bioRxiv2024

Development of fluoro-7-aminocarboxycoumarin-based mitochondrial pyruvate carrier inhibitors as anticancer agents

Reprogrammed metabolism of cancer cells offers a unique target for pharmacological intervention. In the current study, a series of novel and potentially metabolically stable fluoro-substituted aminocarboxycoumarin derivatives are evaluated for their mitochondrial pyruvate carrier (MPC) inhibition properties. Our studies indicate that the aminocarboxycoumarin template elicits potent MPC inhibitory characteristics, and specifically, structure activity relationship studies show that the N-methyl-N-benzyl structural template provides the optimal inhibitory capacity. Further respiratory experiments demonstrate that candidate compounds specifically inhibit pyruvate driven respiration without substantially affecting other metabolic fuels consistent with MPC inhibition. Further, computational homology and inhibitor docking studies illustrate that aminocarboxycoumarin binding characteristics are indicative of reversible covalent bonding with amino acids in the pyruvate binding domain. Epifluorescent microscopy experiments illustrated that FACC2 accumulates in the mitochondria to a similar extent as parent 7ACC2. Additionally, lead candidate aminocarboxycoumarin derivative D7 elicits cancer cell proliferation inhibition specifically in monocarboxylate transporter 1 (MCT1) expressing 4T1, consistent with its ability to accumulate intracellular lactate. In vivo tumor growth studies illustrate that D7 significantly reduces the tumor burden in two isogeneic murine cell lines 4T1 and 67nr. These studies provide novel MPC inhibitors with potential for anticancer applications.

cancer biology↗

bioRxiv2024

Repurposing mitochondrial-targeting anthelmintic agents with GLUT1 inhibitor BAY-876 for cancer therapy

Cancer cells alter their metabolic phenotypes with nutritional change. Single agent approaches targeting mitochondrial metabolism in cancer have failed due to either dose limiting off target toxicities, or lack of efficacy in vivo. To mitigate these clinical challenges, we investigated the potential utility of repurposing FDA approved mitochondrial targeting anthelmintic agents, niclosamide and pyrvinium pamoate, to be combined with GLUT1 inhibitor BAY-876 to enhance the inhibitory capacity of the major metabolic phenotypes exhibited by tumors. To test this, we used breast cancer cell lines MDA-MB-231 and 4T1 which exhibit differing basal metabolic rates of glycolysis and mitochondrial respiration, respectively. Here, we found that specific responses to mitochondrial and glycolysis targeting agents elicit responses that correlate with tested cell lines basal metabolic rates and fuel preference, highlighting the potential to cater metabolism targeting treatment regimens based on specific tumor nutrient handling. Inhibition of GLUT1 with BAY-876 potently inhibited glycolysis in both MDA-MB-231 and 4T1 cells, and niclosamide and pyrvinium pamoate perturbed mitochondrial respiration that resulted in potent compensatory glycolysis in the cell lines tested. In this regard, combination of BAY-876 with both mitochondrial targeting agents resulted in inhibition of compensatory glycolysis and subsequent metabolic crisis. These studies warrant further investigation into targeting tumor metabolism as a combination treatment regimen that can be tailored by basal and compensatory metabolic phenotypes.

cancer biology↗

bioRxiv2023

Tetracycline-dependent inhibition of mitoribosome protein elongation in mitochondrial disease mutant cells suppresses IRE1α to promote cell survival

Mitochondrial diseases are a group of disorders defined by defects in oxidative phosphorylation caused by nuclear- or mitochondrial-encoded gene mutations. A main cellular phenotype of mitochondrial disease mutations are redox imbalances and inflammatory signaling underlying pathogenic signatures of these patients. Depending on the type of mitochondrial mutation, certain mechanisms can efficiently rescue cell death vulnerability. One method is the inhibition of mitochondrial translation elongation using tetracyclines, potent suppressors of cell death in mitochondrial disease mutant cells. However, the mechanisms whereby tetracyclines promote cell survival are unknown. Here, we show that in mitochondrial mutant disease cells, tetracycline-mediated inhibition of mitochondrial ribosome (mitoribosome) elongation promotes survival through suppression of the ER stress IRE1 protein. Tetracyclines increased levels of the splitting factor MALSU1 (Mitochondrial Assembly of Ribosomal Large Subunit 1) at the mitochondria with recruitment to the mitoribosome large subunit. MALSU1, but not other quality control factors, was required for tetracycline-induced cell survival in mitochondrial disease mutant cells during glucose starvation. In these cells, nutrient stress induced cell death through IRE1 activation associated with a strong protein loading in the ER lumen. Notably, tetracyclines rescued cell death through suppression of IRE1 oligomerization and activity. Consistent with MALSU1 requirement, MALSU1 deficient mitochondrial mutant cells were sensitive to glucose-deprivation and exhibited increased ER stress and activation of IRE1 that was not reversed by tetracyclines. These studies show that inhibition of mitoribosome elongation signals to the ER to promote survival, establishing a new interorganelle communication between the mitoribosome and ER with implications in basic mechanisms of cell survival and treatment of mitochondrial diseases.

cell biology↗