Biology subjects

Kelso, M. J.

Publications and source records attributed to Kelso, M. J..

5 recordsLinked to original sources

bioRxiv2026

(E,E)-bisantrene suppresses MYC expression and displays anti-leukemic activity in acute myeloid leukemia

Background: Acute myeloid leukemia (AML) is genetically diverse with a high unmet clinical need for improved treatment options. Dysregulation of the transcription factor MYC plays a central role in AML progression and therapeutic resistance. (E,E)-bisantrene was recently found to inhibit MYC transcription and downstream activity via G-quadruplex DNA stabilization. This study aimed to evaluate the mechanism of action and preclinical activity of (E,E)-bisantrene in AML. Methods: The in vitro and in vivo activity of (E,E)-bisantrene was determined in a variety of AML models (cell lines, xenograft mouse models, and ex vivo human AML mononuclear cells). Transcriptomic, proteomic and phosphoproteomic analyses were performed after treatment with (E,E)-bisantrene. Analyses of -omics data to identify enriched pathways and upstream regulators were performed. Results: (E,E)-bisantrene demonstrated potent anti-proliferative activity across a panel of AML cell lines, inducing apoptosis and reducing S phase proportions. (E,E)-bisantrene significantly prolonged survival in cell- and patient-derived xenograft models of AML. Mechanistically, RNA-seq and proteomic analysis of MOLM13 and MV4-11 cells treated with (E,E)-bisantrene showed significant reductions in the activity of MYC and E2F, together with the cell cycle regulators CDK1/2/4/5. Transcript and protein levels of MYC were reduced in a dose- and time-dependent manner. TP53 and inflammation-associated transcript signatures were also observed. Conclusion: Anti-proliferative activity of (E,E)-bisantrene in preclinical AML models was associated with a downregulation of MYC, CDK1/2/4/5 and E2F. This study supports the ongoing clinical evaluation of (E,E)-bisantrene in AML where MYC is a clinically relevant driver of disease aggressiveness and therapy resistance.

cancer biology↗

bioRxiv2025

Bisantrene potentiates tyrosine kinase inhibitor activity in clear cell renal cell carcinoma

Clear Cell Renal Cell Carcinoma (ccRCC) is the most prevalent kidney cancer and often develops resistance to standard therapies. This study aimed to assess if bisantrene, a multi-mechanistic agent with broad anticancer activity, can enhance the activity of standard of care ccRCC treatments. A panel of ccRCC cell lines were treated with bisantrene alone and in combination with common ccRCC drugs. Bisantrene showed moderate activity as a single agent, but strongly synergized with several ccRCC treatments, especially the tyrosine kinase inhibitors (TKIs) lenvatinib, pazopanib and cabozantinib. Cellular signaling pathways assessed by immunoblotting revealed the TKIs inhibit MET as well as downstream AKT and ERK signaling pathways as single agents. Combination of these TKIs with bisantrene was able to induce sustained downstream AKT inhibition and negate the rebound effect seen with TKI resistance. Overall, bisantrene shows promise as a new therapeutic agent for ccRCC in combination with TKIs.

cancer biology↗

bioRxiv2023

PAI-1 Deficiency Drives Pulmonary Vascular Smooth Muscle Remodeling and Pulmonary Hy-pertension

Pulmonary arterial hypertension (PAH) is a progressive and potentially a rapidly fatal disease characterized by vasoconstriction and remodeling of small pulmonary arteries (PA) leading to increased pulmonary vascular resistance and right heart failure. Central to the remodeling process is a switch of the smooth muscle cells in small PAs (PASMC) to a proliferative, apoptosis-resistant phenotype. There is reason to suspect that the plasminogen activator system may play an important role in the remodeling program in PAH based on its roles in vascular post-injury restenosis, fibrosis, angiogenesis and tumorigenesis. Plasminogen activator inhibitor-1 (PAI-1) is the primary physiological inhibitor of the plasminogen activators - urokinase-type and tissue-type (uPA and tPA, respectively). Immunohisto- chemical and immunoblot analyses revealed that PAI-1 was deficient in smooth muscle areas of small remodeled PAs and early-passage PASMC from subjects with PAH compared to non-PAH controls. PAI1-/- male and female mice developed spontaneous pulmonary vascular remodeling and pulmonary hypertension (PH) as evidenced by significant increase in PA medial thickness, systolic right ventricular pressure, and right ventricular hypertrophy. Lastly, the uPA inhibitors upamostat (WX-671) and amiloride analog BB2-30F down-regulated mTORC1 and SMAD3, restored PAI-1 levels, reduced proliferation, and induced apoptosis in human PAH PASMC. We examined the effect of inhibition of uPA catalytic activity by BB2-30F on the development of SU5416/Hypoxia (SuHx)-induced PH in mice. Vehicletreated SuHx-exposed mice had up-regulated mTORC1 in small PAs, developed pulmonary vascular remodeling and PH, as evidenced by significant increase of PA MT, sRVP, RV hypertrophy, and a significant decrease in the pulmonary artery acceleration time/pulmonary ejection time (PAAT/PET) ratio compared to age- and sex-matched normoxia controls, whereas BB2-30F-treated group was protected from all these pathological changes. Taken together, our data strongly suggest that PAI-1 down- regulation in PASMC from human PAH lungs promotes PASMC hyper-proliferation, remodeling, and spontaneous PH due to unopposed uPA activation. Further studies are needed to determine the potential benefits of targeting the PAI-1/uPA imbalance to attenuate the progression and/or reverse pulmonary vascular remodeling and PH.

cell biology↗

bioRxiv2022

Automated patch clamp screening of amiloride and 5-N,N-hexamethyleneamiloride (HMA) analogs identifies 6-iodoamiloride as a potent acid-sensing ion channel inhibitor.

Acid-sensing ion channels (ASICs) are transmembrane sensors of extracellular acidosis and potential drug targets in several disease indications, including neuropathic pain and cancer metastasis. The K+-sparing diuretic amiloride is a moderate non-specific inhibitor of ASICs and has been widely used as a probe for elucidating ASIC function. In this work, we screened a library of 6-substituted and 5,6-disubstituted amiloride analogs using a custom-developed automated patch-clamp protocol and identified 6-iodoamiloride as a more potent ASIC1 inhibitor. Follow-up IC50 determinations in tsA-201 cells confirmed higher ASIC1 inhibitory potency for 6-iodoamiloride 97 (hASIC1 97 IC50 88 nM cf. amiloride 11 IC50 1.7 M). A similar improvement in activity was observed in ASIC3-mediated currents from rat small diameter dorsal root ganglion neurons (rDRG single-concentration 97 IC50 230 nM cf. 11 IC50 2.7 M). 6-iodoamiloride represents the amiloride analogue of choice for studying the effects of ASIC inhibition on cell physiology.

pharmacology and toxicology↗

bioRxiv2021

Novel amiloride derivatives that inhibit bacterial motility across multiple strains and stator types

The bacterial flagellar motor (BFM) is a protein complex that confers motility to cells and contributes to survival and virulence. The BFM consists of stators that are ion-selective membrane protein complexes and a rotor that directly connects to a large filament, acting as a propeller. The stator complexes couple ion transit across the membrane to torque that drives rotation of the motor. The most common ion gradients that drive BFM rotation are protons (H+) and sodium ions (Na+). The sodium-powered stators, like those in the PomAPomB stator complex of Vibrio spp, can be inhibited by sodium channel inhibitors, in particular, by phenamil, a potent and widely used inhibitor. However, relatively few new sodium-motility inhibitors have been described since the discovery of phenamil. In this study, we characterised two possible motility inhibitors HM2-16F and BB2-50F from a small library of previously reported amiloride derivatives. We used three approaches: effect on rotation of tethered cells, effect on free swimming bacteria and effect on rotation of marker beads. We showed that both HM2-16F and BB2-50F stopped rotation of tethered cells driven by Na+ motors comparable to phenamil at matching concentrations, and could also stop rotation of tethered cells driven by H+ motors. Bead measurements in presence and absence of stators confirmed that the compounds did not inhibit rotation via direct association with the stator, in contrast to the established mode of action of phenamil. Overall, HM2-16F and BB2-50F stopped swimming in both Na+ and H+ stator types, and in pathogenic and non-pathogenic strains. ImportanceHere we characterised two novel amiloride derivatives in the search for antimicrobial compounds that target bacterial motility. Our two compounds were shown to inhibit flagellar motility at 10 M across multiple strains, from non-pathogenic E. coli with flagellar rotation driven by proton or chimeric sodium-powered stators, to proton-powered pathogenic E. coli (EHEC/UPEC) and lastly in sodium-powered Vibrio alginolyticus. Broad anti-motility compounds such as these are important tools in our efforts control virulence of pathogens in health and agricultural settings.

microbiology↗