Biology subjects

Cagan, R.

Publications and source records attributed to Cagan, R..

7 recordsLinked to original sources

bioRxiv2026

Macrophage-Derived PDGF-BB and GDF-15 Promote Drug Resistance in KRAS-Mutant Colorectal Cancer

Macrophages are abundant in the colorectal tumour microenvironment and can alter drug response. Using mouse Apc/Kras/Trp53 (AKP) colorectal cancer organoids, we found that macrophages and/or macrophage-conditioned medium reduced sensitivity to the MEK inhibitor trametinib and the pan-RAS inhibitor RMC-6236. In contrast, macrophage-conditioned medium had little effect on regorafenib and increased sensitivity to dabrafenib, suggesting that resistance depends on the inhibitory profile of each drug. Secretome profiling identified PDGF-BB and GDF-15 as candidate mediators. Adding both ligands to organoid medium reproduced much of the conditioned-medium effect, whereas either ligand alone was insufficient. Inhibition of PDGFR or RET partially reduced drug resistance, suggesting that PDGF-BB and GDF-15 likely act through canonical signalling by that additional macrophage-derived signals also contribute. Kinome profiling pointed to increased tyrosine kinase signalling during trametinib treatment, with SRC family kinases emerging as a key downstream node. Consistent with this, SRC inhibition reduced the difference between control and conditioned-medium responses. The multi-kinase inhibitor masitinib--which targets several kinases along this resistance network--strongly restored sensitivity to trametinib and RMC-6236. Together, these data define a macrophage-driven resistance network in KRAS-mutant colorectal cancer organoids and support combined inhibition of RAS-pathway and tyrosine kinase signalling.

cancer biology↗

bioRxiv2025

Alternative Anastrozole Target CYP4V2 Impairs Neurons in Preclinical Models of Inherited Tauopathy

Tauopathies, including Alzheimer disease, are neurodegenerative diseases characterized by the pathological aggregation of the microtubule-associated protein Tau (MAPT). This study explores the neuroprotective properties of anastrozole, a clinical Aromatase inhibitor, in both a Drosophila tauopathy model expressing human MAPTR406W and isogenic pairs of human induced pluripotent stem cell-derived cortical neurons expressing MAPT mutations. The Aromatase inhibitor anastrozole, initially identified in a Drosophila MAPTR406W drug screen, reduced oxidative stress and Tau phosphorylation in cultured cortical neurons. Its protective effects were not mediated by Aromatase activity or cholesterol metabolism: screening in Drosophila identified CYP4V2 as a potential off-target. Knockdown of CYP4V2 in MAPTR406W neurons recapitulated protection against oxidative stress-induced cell death. These findings position anastrozole and its offtarget CYP4V2 as novel therapeutic avenues for primary tauopathies and potentially Alzheimers disease and related dementias by reducing Tau phosphorylation and susceptibility to oxidative stress.

neuroscience↗

bioRxiv2024

Flow zoometry of Drosophila

Drosophila serves as a highly valuable model organism across numerous fields including genetics, immunology, neuroscience, cancer biology, and developmental biology. Central to Drosophila-based biological research is the ability to perform comprehensive genetic or chemical screens. However, this research is often limited by its dependence on laborious manual handling and analysis, making it prone to human error and difficult to discern statistically significant or rare events amid the noise of individual variations resulting from genetic and environmental factors. In this article we present flow zoometry, a whole-animal equivalent of flow cytometry for large-scale, individual-level, high-content screening of Drosophila. Our flow zoometer automatically clears the tissues of Drosophila melanogaster, captures three-dimensional (3D) multi-color fluorescence tomograms of single flies with single-cell volumetric resolution at an unprecedented throughput of over 1,000 animals within 48 hours (24 hr for clearing; 24 hr for imaging), and performs AI-enhanced data-driven analysis - a task that would traditionally take months or years with manual techniques. To demonstrate its broad applications, we employed the flow zoometer in various laborious screening assays, including those in toxicology, genotyping, and tumor screening. Flow zoometry represents a pivotal evolution in high-throughput screening technology: previously from molecules to cells, now from cells to whole animals. This advancement serves as a foundational platform for "statistical spatial biology", to improve empirical precision and enable serendipitous discoveries across various fields of biology.

bioengineering↗

bioRxiv2023

WNT Signalling Promotes NF-κB Activation and Drug Resistance in KRAS-Mutant Colorectal Cancer

Approximately 40% of colorectal cancer (CRC) cases are characterized by KRAS mutations, rendering them insensitive to most CRC therapies. While the reasons for this resistance remain incompletely understood, one key aspect is genetic complexity: in CRC, oncogenic KRAS is most commonly paired with mutations that alter WNT and P53 activities ("RAP"). Here, we demonstrate that elevated WNT activity upregulates canonical (NF-{kappa}B) signalling in both Drosophila and human RAS mutant tumours. This upregulation required Toll-1 and Toll-9 and resulted in reduced efficacy of RAS pathway targeted drugs such as the MEK inhibitor trametinib. Inhibiting WNT activity pharmacologically significantly suppressed trametinib resistance in RAP tumours and more genetically complex RAP-containing patient avatar models. WNT/MEK drug inhibitor combinations were further improved by targeting brm, shg, ago, rhoGAPp190 and upf1, highlighting these genes as candidate biomarkers for patients sensitive to this duel approach. These findings shed light on how genetic complexity impacts drug resistance and proposes a therapeutic strategy to reverse this resistance.

cancer biology↗

bioRxiv2023

Colon Cancer Cells Evade Drug Action by Enhancing Drug Metabolism

Colorectal cancer (CRC) is the second most deadly cancer worldwide. One key reason is the failure of therapies that target RAS proteins, which represent approximately 40% of CRC cases. Despite the recent discovery of multiple alternative signalling pathways that contribute to resistance, durable therapies remain an unmet need. Here, we use liquid chromatography/ mass spectrometry (LC/MS) analyses on Drosophila CRC tumour models to identify multiple metabolites in the glucuronidation pathway--a toxin clearance pathway--as upregulated in trametinib-resistant RAS/APC/P53 ("RAP") tumours compared to trametinib-sensitive RASG12V tumours. Elevating glucuronidation was sufficient to direct trametinib resistance in RASG12Vanimals while, conversely, inhibiting different steps along the glucuronidation pathway strongly reversed RAP resistance to trametinib. For example, blocking an initial HDAC1-mediated deacetylation step with the FDA-approved drug vorinostat strongly suppressed trametinib resistance in Drosophila RAP tumours. We provide functional evidence that pairing oncogenic RAS with hyperactive WNT activity strongly elevates PI3K/AKT/GLUT signalling, which in turn directs elevated glucose and subsequent glucuronidation. Finally, we show that this mechanism of trametinib resistance is conserved in an KRAS/APC/TP53 mouse CRC tumour organoid model. Our observations demonstrate a key mechanism by which oncogenic RAS/WNT activity promotes increased drug clearance in CRC. The majority of targeted therapies are glucuronidated, and our results provide a specific path towards abrogating this resistance in clinical trials.s

cancer biology↗

bioRxiv2021

Crowdsourced Identification of Multi-Target Kinase Inhibitors for RET- and TAU- Based Disease: the Multi-Targeting Drug DREAM Challenge

A continuing challenge in modern medicine is the identification of safer and more efficacious drugs. Precision therapeutics, which have one molecular target, have been long promised to be safer and more effective than traditional therapies. This approach has proven to be challenging for multiple reasons including lack of efficacy, rapidly acquired drug resistance, and narrow patient eligibility criteria. An alternative approach is the development of drugs that address the overall disease network by targeting multiple biological targets ( polypharmacology). Rational development of these molecules will require improved methods for predicting single chemical structures that target multiple drug targets. To address this need, we developed the Multi-Targeting Drug DREAM Challenge, in which we challenged participants to predict single chemical entities that target pro-targets but avoid anti-targets for two unrelated diseases: RET-based tumors and a common form of inherited Tauopathy. Here, we report the results of this DREAM Challenge and the development of two neural network-based machine learning approaches that were applied to the challenge of rational polypharmacology. Together, these platforms provide a potentially useful first step towards developing lead therapeutic compounds that address disease complexity through rational polypharmacology. Author SummaryMany modern drugs are developed with the goal of modulating a single cellular pathway or target. However, many drugs are, in fact, dirty; they target multiple cellular pathways or targets. This phenomenon is known as multi-targeting or polypharmacology. While some strive to develop cleaner therapeutics that eliminate secondary targets, recent work has shown that multi-targeting therapeutics have key advantages for a variety of diseases. However, while multi-targeting drugs that affect a precisely-defined profile of targets may be more effective, it is difficult to computationally predict which molecules have desirable target profiles. Here, we report the results of a competitive crowdsourcing project (the Multi-Targeting Drug DREAM Challenge), where we challenged participants to predict chemicals that have desired target profiles for cancer and neurodegenerative disease.

pharmacology and toxicology↗

bioRxiv2020

Drosophila RASopathy Models Identify Disease Subtype Differences and Biomarkers of Drug Efficacy

RASopathies represent a family of mostly autosomal dominant diseases that are caused by missense variants in the RAS/MAPK pathway. In aggregate, they are among the more common Mendelian disorders. They share overlapping pathologies that include structural birth and developmental defects that affect the heart, craniofacial and skeletal, lymphatic, and nervous systems. Variants in different genes--including those encoding KRAS, NRAS, BRAF, RAF1, and SHP2--are associated with overlapping but distinct phenotypes. Here, we report an analysis of 13 Drosophila transgenic lines, each expressing a different human disease isoform associated with a form of RASopathy. Similar to their human counterparts, each Drosophila line has common aspects but also important phenotypic distinctions including signaling pathways as well as response to therapeutics. For some lines, these differences represent activation of pathways outside the core RAS signaling pathway including the Hippo and SAPK/JNK signaling networks. We identified two classes of clinically relevant drugs, statins and histone deacetylase inhibitors, that improved viability across most RASopathy lines; in contrast, several canonical RAS pathway inhibitors proved poorly effective against, e.g., SHP2-expressing lines encoded by PTPN11. Our study provides a whole animal platform for comparison of a large number of RASopathy-associated variants. Among these variants we have identified differences in tissue phenotypes, in activation signaling pathways in biomarkers of disease progression and drug efficacy, and suggest drug classes that can be tolerated over long treatment periods for consideration in broad RASopathy trials.

developmental biology↗