Biology subjects

Crowley, M. R.

Publications and source records attributed to Crowley, M. R..

3 recordsLinked to original sources

bioRxiv2024

Development of a small-molecule epigenetic regenerative therapy. Subcutaneous administration of alginate formulations with high loads of zebularine and retinoic acid promotes tissue growth, vascularization and innervation and induces extensive epigenetic repatterning

Recently, zebularine, a small-molecule epigenetic inhibitor and retinoic acid, acting as a transcriptional activator, have been found to induce tissue regeneration. In this study, the pro-regenerative properties of zebularine and retinoic acid were combined with the potential of the alginate carrier to expand its therapeutic possibilities. Alginate formulations of zebularine and retinoic acid were developed for subcutaneous administration to mice. Hydrophilic zebularine formed a homogenous formulation with extreme drug loadings reaching 240 mg of zebularine per 1 ml of 2% sodium alginate, while hydrophobic retinoic acid, 0.8 mg/ml, dispersed as fine crystals. Cell culture tests exhibited no significant cytotoxicity of the alginate formulations. Subcutaneous administration of zebularine and retinoic acid in 2% sodium alginate promoted regenerative responses in a mouse model of ear pinna punch wound mice involving the restoration of tissue architecture, nerve and vessel growth, and extensive epigenetic and transcriptional repatterning with no adverse effects observed in the animals. Significant trancriptomic responses to the epigenetic treatment included the induction of epithelium development genes contrasted with the downregulation of muscle development genes on day 7 post-injury. Among the remarkable changes in global gene methylation are those in neurodevelopmental genes. In vitro studies showed rapid zebularine but no retinoic acid discharge from the alginate formulations. Live ultrasound imaging demonstrated gradual absorption of the subcutaneously injected alginate formulations, which may explain the in vivo activity of retinoic acid following subcutaneous administration. Effective induction of tissue regeneration together with a high safety profile and of the subcutaneously administered pro-regenerative alginate formulations opens the way to testing further regenerative therapies for hard-to-reach lesions.

bioengineering↗

bioRxiv2022

ST6GAL1 sialyltransferase promotes acinar to ductal metaplasia and pancreatic cancer progression

The role of aberrant glycosylation in pancreatic ductal adenocarcinoma (PDAC) remains an under-investigated area of research. In this study, we determined that the ST6GAL1 sialyltransferase, which adds 2,6-linked sialic acids to N-glycosylated proteins, is upregulated in patients with early-stage PDAC, and further increased in advanced disease. A tumor-promoting function for ST6GAL1 was elucidated using tumor xenograft models with human PDAC cells. Additionally, we developed a genetically-engineered mouse (GEM) with transgenic expression of ST6GAL1 in the pancreas, and found that mice with dual expression of ST6GAL1 and oncogenic KRASG12D have greatly accelerated PDAC progression and mortality compared with mice expressing KRASG12D alone. As ST6GAL1 imparts progenitor-like characteristics, we interrogated ST6GAL1s role in acinar to ductal metaplasia (ADM), a process that fosters neoplasia by reprogramming acinar cells into ductal, progenitor-like cells. We confirmed that ST6GAL1 promotes ADM using multiple models including the 266-6 cell line, GEM-derived organoids and tissues, and an in vivo model of inflammation-induced ADM. EGFR is a key driver of ADM and is known to be activated by ST6GAL1-mediated sialylation. Importantly, EGFR activation was dramatically increased in acinar cells and organoids from mice with transgenic ST6GAL1 expression. These collective results highlight a novel glycosylation-dependent mechanism involved in early stages of pancreatic neoplasia.

cancer biology↗

bioRxiv2019

Therapeutically actionable PAK4 is amplified, overexpressed and involved in bladder cancer progression

Muscle-invasive bladder carcinomas (MIBCs) are aggressive genitourinary malignancies. Disease incidence and survival rates vary based on aggressiveness and treatment options. Metastatic urothelial carcinoma of the bladder is generally incurable by current chemotherapy and leads to early mortality. For a minority ([~]20%) of patients, T-cell checkpoint inhibitors provide durable benefits following prior platinum therapy. Recent studies have identified molecular subtypes of MIBCs with different sensitivities to frontline therapy, suggesting heterogeneity in these tumors and pointing to the importance of molecular characterization of MIBCs to provide effective treatment. We have performed multi-omic profiling of the kinome to identify therapeutic targets that are overexpressed in a subset of BLCAs. Our analyses revealed amplification and overexpression of P21 (RAC1) activated kinase 4 (PAK4) in a subset of BLCAs. For these tumors, multiplex kinase assay profiling identified corresponding PAK4 target substrates. By performing experiments using cultured bladder cancer cells, we confirmed the role of PAK4 in BLCA cell proliferation and invasion. Furthermore, our studies showed that a PAK4 inhibitor was effective in curtailing growth of BLCA cells. Transcriptomic analyses identified elevated expression of another kinase, Protein Tyrosine Kinase 6 (PTK6), upon treatment with a PAK4 inhibitor. Similarly, RNA interference of PAK4 led to elevated expression of PTK6. Treatment with a combination of kinase inhibitors (vandetanib and dasatinib) showed enhanced sensitivity compared to either drug alone. Thus, PAK4 may be therapeutically actionable for a subset of MIBC patients with amplified and/or overexpressed PAK4 in their tumors. Our results also indicate that combined inhibition of PAK4 and PTK6 may overcome resistance to PAK4. These observations warrant clinical investigations with selected BLCA patients.

cancer biology↗