Danyelle M. Townsend’s research while affiliated with Medical University of South Carolina and other places

Cytochrome P450 3A4 (CYP3A4) is a crucial enzyme involved in the Phase I metabolism of numerous medications used in clinical practice. Its potential significance in pediatric pharmacotherapy is underscored by the unique metabolic profile of children, which differs markedly from adults, especially in neonates, infants, and young children due to developmental changes in enzyme activity. This review explores the critical role of CYP3A4 in the metabolism of drugs used in the pediatric population, with a particular focus on combination drug therapies. Given the high potential for drug-drug interactions in combination therapies, understanding the modulation of CYP3A4 activity is essential for optimizing therapeutic outcomes and minimizing adverse effects. This paper further examines the structural similarities between these medications and bergamottin, a known CYP3A4 inhibitor found in citric fruits such as grapefruit. Variability in CYP3A4 activity, influenced by genetic polymorphisms, developmental stage, and external factors, necessitates careful consideration in the prescribing and management of drugs in children. This review corroborates the need for personalized medicine approaches and enhanced pharmacovigilance to ensure the safe and effective use of CYP3A4-metabolized drugs in the pediatric population. Graphical Abstract

Background Cigarette smoking is a recognized risk factor for orthopedic disorders, particularly intervertebral disc (IVD) degenerative disease. However, the IVD pathophysiology, especially the spatial–temporal remodeling progression in the context of cigarette smoking, remains unclear. This study aimed to address this knowledge gap through a quantitative assessment of IVD structural composition and diffusion properties using a Sprague–Dawley rat model. Methods Twenty‐four rats were divided into control and smoke exposure cohorts, each with two sub‐groups of six rats. One smoke exposure sub‐group was sacrificed after 2 months of daily cigarette smoke exposure in a custom smoking apparatus, while the other was sacrificed after an additional 5 months of smoke cessation. The control groups were age‐matched to the smoke exposure groups. A fluorescent recovery after photobleaching (FRAP) technique was used to determine solute diffusivities and multi‐photon excitation (MPE) imaging was performed to characterize structural changes in the annulus fibrosus (AF), nucleus pulposus (NP), and cartilage endplate (CEP). Results A decrease in diffusivity was observed in the CEP and the AF (radial direction only) after 2 months of smoke exposure. MPE imaging showed aberrant CEP calcification and reduced AF radial collagen fiber bundle diameter, suggesting that the IVD exhibits regionally dependent structural remodeling due to smoke exposure. Furthermore, the smoke cessation group showed deteriorating alterations of structure and diffusivities in all three‐disc regions, including the NP, indicating that five‐month smoke cessation alone didn't reverse the progression of IVD degenerative remodeling during aging. Conclusion This study advances the understanding of IVD pathophysiology in the context of cigarette smoke exposure and cessation, laying the groundwork for potential earlier diagnosis and optimized interventions.

The design and synthesis of antiviral compounds were guided by computationally predicted data against highly conserved non-structural proteins (Nsps) of the SARS-CoV-2 coronavirus. Chromenephenylmethanone-1 (CPM-1), a novel biphenylpyran (BPP), was selected from a unique natural product library based on in silico docking scores to coronavirus Nsps with high specificity to the methyltransferase protein (2′-O-MTase, Nsp10–16), which is responsible for viral mRNA maturation and host innate immune response evasion. To target the 2′-O-MTase, CPM-1, along with intermediate BPP regioisomers, tetrahydrophenylmethanones (TPMs), were synthesized and structurally validated via nuclear magnetic resonance (NMR) data and DP4+ structure probability analyses. To investigate the activity of these BPPs, the following in vitro assays were conducted: SARS-CoV-2 inhibition, biochemical target validation, mutagenicity, and cytotoxicity. CPM-1 possessed notable activity against SARS-CoV-2 with 98.9% inhibition at 10 µM and an EC50 of 7.65 µM, as well as inhibition of SARS-CoV-2’s 2′-O-MTase (expressed and purified) with an IC50 of 1.5 ± 0.2 µM. In addition, CPM-1 revealed no cytotoxicity (CC50 of >100 µM) or mutagenicity (no frameshift or base-pair mutations). This study demonstrates the potential of computational modeling for the discovery of natural product prototypes followed by the design and synthesis of drug leads to inhibit the SARS-CoV-2 2′-O-MTase.

In this mini-review, we discuss the role of NF-κB, a proinflammatory transcription factor, in the expression of genes involved in inflammation, proliferation, and apoptosis pathways, and link it with prognosis of various human cancers, particularly non-small cell lung cancer (NSCLC). We and others have shown that NF-κB activity can be impacted by post-translational S-glutathionylation through reversible formation of a mixed disulfide bond between its cysteine residues and glutathione (GSH). Clinical data analysis showed that high expression of NF-κB correlated with shorter overall survival (OS) in NSCLC patients, suggesting a tumor promotion function for NF-κB. Moreover, NF-κB expression was associated with tumor stage, lymph node metastasis, and 5-year OS in these patients. NF-κB was over-expressed in the cytoplasm of tumor tissue compared to adjacent normal tissues. S-glutathionylation of NF-κB caused negative regulation by interfering with DNA binding activities of NF-κB subunits. In response to oxidants, S-glutathionylation of NF-κB also correlated with enhanced lung inflammation. Thus, S-glutathionylation is an important contributor to NF-κB regulation and clinical results highlight the importance of NF-κB in NSCLC, where NF-κB levels are associated with unfavorable prognosis.

Doxorubicin (DOX) loaded liposomes have been used and studied in the last decades due to the significant decrease in DOX induced cardiac and systemic toxicity relative to administration of free drug. Therefore, new strategies are sought to improve DOX delivery and antitumor activity, while avoiding side effects. Recently, folate-coated pH-sensitive liposomes (SpHL-Fol) have been studied as a tool to enhance cellular uptake and antitumor activity of paclitaxel and DOX in breast cancer cells expressing folate receptor (FR+). However, the elucidation of folate functionalization relevance in DOX-loaded SpHL (SpHL-DOX-Fol) in different cell types (MDA-MB-231, MCF-7, and A549), as well as, the complete safety evaluation, is necessary. To achieve these objectives, SpHL-DOX-Fol was prepared and characterized as previously described. Antitumor activity and acute toxicity were evaluated in vivo through direct comparison of free DOX verses SpHL-DOX, a well-known formulation to reduce DOX cardiotoxicity. The obtained data are crucial to support future translational research. Liposomes showed long-term stability, suitable for biological use. Cellular uptake, cytotoxicity, and percentage of migration inhibition were significantly higher for MDA-MB-231 (FR+) treated with SpHL-DOX-Fol. In addition, SpHL-DOX-Fol demonstrated a decrease in the systemic toxic effects of DOX, mainly in renal and cardiac parameters evaluation, even using a higher dose (20 mg/kg). Collectively these data build the foundation of support demonstrating that SpHL-DOX-Fol could be considered a promising drug delivery strategy for the treatment of FR+ breast tumors.

While recent targeted and immunotherapies in malignant melanoma are encouraging, most patients acquire resistance, implicating a need to identify additional drug targets to improve outcomes. Recently, attention has been given to pathways that regulate redox homeostasis, especially the lipid peroxidase pathway that protects cells against ferroptosis. Here we identify microsomal glutathione S-transferase 1 (MGST1), a non-selenium-dependent glutathione peroxidase, as highly expressed in malignant and drug resistant melanomas and as a specific determinant of metastatic spread and therapeutic sensitivity. Loss of MGST1 in mouse and human melanoma enhanced cellular oxidative stress, and diminished glycolysis, oxidative phosphorylation, and pentose phosphate pathway. Gp100 activated pmel-1 T cells killed more Mgst1 KD than control melanoma cells and KD cells were more sensitive to cytotoxic anticancer drugs and ferroptotic cell death. When compared to control, mice bearing Mgst1 KD B16 tumors had more CD8+ T cell infiltration with reduced expression of inhibitory receptors and increased cytokine response, large reduction of lung metastases and enhanced survival. Targeting MGST1 alters the redox balance and limits metastases in melanoma, enhancing the therapeutic index for chemo- and immunotherapies.