Biology subjects

Jackson, T. R.

Publications and source records attributed to Jackson, T. R..

5 recordsLinked to original sources

bioRxiv2024

HDAC inhibitor derivatives induce differentiation of leukemic cells through two distinct and separable mechanisms

Acute myeloid leukaemia (AML) is a haematopoietic malignancy comprising different genetic subtypes with a common hallmark of differentiation arrest. In abnormal haematopoiesis, overcoming the differentiation blockade has emerged as an attractive therapeutic strategy. In a screen with genetically distinct AML cell lines, histone deacetylase inhibitors (HDACis) were observed to cause an upregulation in the expression of CD11b, a myeloid differentiation marker. These caused changes in cell morphology, block in proliferation, and cell cycle arrest at the G1 phase. To gain insights onto the mechanism of these compounds, we planned to prepare inactive probes devoid of the zinc binding motif. However, these compounds were unexpectedly still able to initiate differentiation, albeit through a distinct target and via a G2 arrest. Subsequent RNA sequencing studies supported the differentiation phenotype for the HDACis and highlighted the role of cell cycle regulatory kinases for the effect observed in the probe molecules. We then showed that these inhibit Aurora A and GSK3 kinases, suggesting their potential as therapeutic targets for differentiation therapy in AML. Our work supports the importance of properly validating inactive tool compounds and their potential to identify novel targets.

pharmacology and toxicology↗

bioRxiv2022

High-throughput widefield fluorescence imaging of 3D samples using deep learning for 2D projection image restoration

Fluorescence microscopy has become a core tool for visualizing and quantifying the spatial and temporal dynamics of complex biological processes. Thanks to its low cost and ease-of-use, widefield fluorescent imaging remains one of the most widely used fluorescence microscopy imaging modalities. To accomplish imaging of 3D samples, conventional fluorescence imaging entails acquiring a sequence of 2D images spaced along the z-dimension, typically called a z-stack. Oftentimes, the next step is to project the 3D volume into a single 2D image, as 3D image data can be cumbersome to manage and challenging to analyze and interpret, effectively limiting the utlity of z-dimensional information. Furthermore, z-stack acquisition is often time-consuming and consequently may induce photodamage to the biological sample, which are both major hurdles for its application in experiments that require high-throughput, such as drug screening. As an alternative to z-stacks, axial sweep acquisition schemes have been proposed to circumvent these drawbacks and offers potential of 100-fold faster image acquisition for 3D-samples compared to z-stack acquisition but unfortunately results in blurry, low-quality raw 2D z-projected images. We propose a novel workflow to combine axial z-sweep acquisition with deep learning-based image restoration, ultimately enabling high-throughput and high-quality imaging of complex 3D-samples using 2D projection images. To demonstrate the capabilities of our proposed workflow, we apply it to live-cell imaging of 3D tumor spheroids and find we can produce high-fidelity images appropriate for quantitative analysis. Therefore, we conclude that combining axial z-sweep image acquisition with deep learning-based image restoration enables high-throughput and high-quality fluorescence imaging of complex 3D biological samples.

cell biology↗

bioRxiv2021

A novel tubulin binding molecule drives differentiation of acute myeloid leukaemia cells

Acute Myeloid Leukaemia (AML) continues to have a poor prognosis, especially in the elderly. One reason for this is that many treatment regimens are not well tolerated by elderly patients. Much current focus is on the development of therapies that can target specific vulnerabilities of AML while having fewer toxic side effects. However, despite much recent progress in developing better drugs, many patients with AML still die within a year of diagnosis, partly due to the fact that it is difficult to identify therapeutic targets that are effective across multiple AML subtypes. One common factor across AML subtypes is the presence of a block in differentiation. Thus screening for compounds that can overcome this block in genetically diverse AML models should allow for the identification of agents that are not dependent on a specific mutation for their efficacy. Here, we used a phenotypic screen to identify novel compounds that stimulate differentiation in several AML cell lines. Lead compounds were shown to decrease tumour burden and to increase survival in vivo. Using multiple complementary target deconvolution approaches, these compounds were revealed to be anti-mitotic tubulin disruptors that cause differentiation by inducing a G2-M mitotic arrest. Together, these results reveal a novel function for tubulin disruptors in causing differentiation of AML cells.

cancer biology↗

bioRxiv2020

A phenotypic screen identifies a compound series that induces differentiation of acute myeloid leukemia cells in vitro and shows anti-tumour effects in vivo

Induction of differentiation is a promising therapeutic strategy against acute myeloid leukemia. However, current differentiation therapies are effective only to specific patient populations. To identify novel differentiation agents with wider efficacy, we developed a phenotypic high-throughput screen with a range of genetically diverse cell lines. From the resulting hits, one chemical scaffold was optimised in terms of activity and physicochemical properties to yield OXS007417, which was also able to decrease tumour volume in a murine in vivo xenograft model.

cancer biology↗

bioRxiv2019

Tissue mechanics drives epithelialization, goblet cell regeneration, and restoration of a mucociliated epidermis on the surface of embryonic aggregates.

Injury, surgery, and disease often disrupt tissues and it is the process of regeneration that aids the restoration of architecture and function. Regeneration can occur through multiple strategies including induction of stem cell expansion, transdifferentiation, or proliferation of differentiated cells. We have uncovered a case of regeneration that restores a mucociliated epithelium from mesenchymal cells. Following disruption of embryonic tissue architecture and assembly of a compact mesenchymal aggregate, regeneration first involves restoration of an epithelium, transitioning from mesenchymal cells at the surface of the aggregate. Cells establish apico-basal polarity within 5 hours and a mucociliated epithelium within 24. Regeneration coincides with nuclear translocation of the putative mechanotransducer YAP1 and a sharp increase in aggregate stiffness, and regeneration can be controlled by altering stiffness. We propose that regeneration of a mucociliated epithelium occurs in response to biophysical cues sensed by newly exposed cells on the surface of a disrupted mesenchymal tissue.

developmental biology↗