Voxtalisib Hydrochloride

Although hypertrophic scarring affects ∼91% of burn patients annually, there is no drug to prevent this common complication. Hypertrophic scars are a result of dysregulated wound healing, characterised by persistent myofibroblast transformation and the excessive accumulation of extracellular matrix (ECM). Due to the multi-mechanistic nature of the scarring process, target-based approaches for identifying novel drugs have failed. Primary human dermal fibroblasts, derived from burn scar tissue, were exposed to transforming growth factor-beta 1 (TGF-β1) to induce myofibroblast transformation. A phenotypic screening assay, measuring alpha-smooth muscle actin (α-SMA) expression, was developed to screen 1,954 approved drugs. Drugs that elicited >80% inhibition of α-SMA expression, and >80% cell viability were progressed as candidate drugs. Anti-myofibroblast activity of the candidates was confirmed before investigating their effects on extracellular matrix (ECM) production and keratinocyte epithelial-mesenchymal transition (EMT). TGF-β1 induced myofibroblast transformation in primary human dermal fibroblasts (E_max = >3 ng/mL). The assay was optimised and validated (Z' = 0.59), before screening 1,954 approved drugs. 90 drugs were identified as hits and hydroxypyridone anti-fungals selected for further testing. Concentration-response curves for these drugs confirmed their concentration-dependent anti-myofibroblast activity (IC₅₀ = 1.4 - 16.7 μM). Hydroxypyridone anti-fungals were also found to successfully reduce ECM production and keratinocyte EMT. This is the first study to screen approved drugs in primary human dermal fibroblasts. Hydroxypyridone anti-fungals were found to prevent myofibroblast transformation, ECM production and keratinocyte EMT suggesting they could be repurposed to prevent hypertrophic scarring.

Glioblastoma (GBM) is the most aggressive brain tumor contributed to tumor growth by cancer stem cells (CSCs). Targeting CSCs is vital to preventing differentiation into cancer cells, their proliferation, and treatment resistance. According to research, PI3K/AKT/mTOR signaling is active in GBM and GBMCSCs. Anticancer medications combined with ultrasound application have been proposed as a strategy to increase the drug intake of cancer cells. This study aims to investigate the effects of inhibition of PI3K/ AKT/ mTOR pathway with dual inhibitor Voxtalisib (Vox; also known as XL765) and low intensity pulsed ultrasound (LIPUS) combinations in GBM and GBMCSCs in the point of cell survival. F-actin was also used to evaluate cell motility.

GBMCSCs were isolated from the human glioblastoma U87 MG cell line using the fluorescence-activated cell sorting (FACS) method. Cells were exposed to various concentrations of Vox, LIPUS, and their combinations. Cell count and viability assay was used to determine drug delivery doses. F-actin and mTOR immunofluorescence staining were used to identify cytoskeletal alterations and PI3K/AKT/mTOR signal pathway suppression, respectively. Additionally, the migration capacity of cells was shown with standard wound-healing experiments.

High doses of Vox+LIPUS inhibited mTOR and decreased the viability in both cell groups. Inhibiting mTOR activated autophagy, and LIPUS increased autophagy in GBM cells. However, GBMCSCs were resistant to autophagy even at high drug dosages. Both in GBM and GBMCSCs, combinations of Vox and LIPUS were observed to decrease F-actin density and cell motility.

The combination of Vox+LIPUS has increased drug effectiveness in targeted GBM and GBMCSCs. Combinatory treatment with PI3K/AKT/mTOR signaling pathway and LIPUS has been thought to help develop more effective therapeutic approaches for GBM.