Combinatorial targeting of telomerase and DNA-PK induces synergistic apoptotic effects against Pre-B acute lymphoblastic leukemia cells.

BACKGROUND: Due to the high demand for novel approaches for leukemia-targeted therapy, this study investigates the impact of DNA-PK inhibitor NU7441 on the sensitivity of pre-B ALL cells to the telomerase inhibitor MST-312. METHODS: The study involved NALM-6 cells treated with MST-312 and NU7441, assessing their viability and metabolic activity using trypan blue and MTT assays. The study also evaluated apoptosis, gene expression changes, and DNA damage using flow cytometry, qRT-PCR, and micronucleus assays. The binding energy of MST-312 in the active site of telomerase was calculated using molecular docking. RESULTS: The study's findings revealed a synergistic decline in both cell viability and metabolic activity in NALM-6 cells when exposed to the combined treatment of MST-312 and NU7441, and this decrease occurred without any adverse effects on healthy PBMC cells. Furthermore, the combination treatment exhibited a significantly higher induction of apoptosis than treatment with MST-312 alone, as observed through flow cytometry assay. qRT-PCR analysis revealed that this enhanced apoptosis was associated with a notable downregulation of Bcl-2 expression and an upregulation of Bax gene expression. Moreover, the combination therapy decreased expression levels of hTERT and c-Myc genes. The micronucleus assay indicated that the combination treatment increased DNA damage in NALM-6 cells. Also, a good conformation between MST-312 and the active site of telomerase was revealed by docking data. CONCLUSIONS: The study suggests that simultaneous inhibition of telomerase and DNA-PK in pre-B ALL presents a novel targeted therapy approach.

Cheminformatics Bioprospection of Broad Spectrum Plant Secondary Metabolites Targeting the Spike Proteins of Omicron Variant and Wild-Type SARS-CoV-2.

The spike protein (SP) of SARS-CoV-2 (SC-2) is susceptible to high mutation and has contributed to the multiple waves of COVID-19 being experienced. Hence, targeting the SP remains a logical approach in the development of potent therapeutics against SARS-CoV-2. Here, a computational technique was adopted to identify broad-spectrum plant secondary metabolites with indigenous relevance in the management of respiratory infections against the SPs of the SC-2 wild- type (SC-2WT) and omicron variants. Following 100 ns molecular dynamic (MD) simulation and binding free energy calculation of the top five compounds identified through molecular docking, maysin (SC-2WT (-34.85 kcal/mol), omicron (-38.88 kcal/mol)) and geraniin (SC-2WT (-36.90 kcal/mol) omicron (-31.28 kcal/mol)) had better broad-spectrum activities for the investigated SPs than zafirlukast (SC-2WT (-33.73 kcal/mol) omicron (-22.38 kcal/mol)). Furthermore, 6-hydroxycyanidin-3-rutinoside (-42.97 kcal/mol) and kaempferol-7-glucoside (-37.11 kcal/mol) had the best affinity for the SPs of omicron and SC-2WT, respectively. Interestingly, except for Kaempferol-7-glucoside against omicron SP, all the top-ranked compounds were thermodynamically stable with the SP of both variants, and this observation was linked to the number, nature, and bond length in the resulting complexes in each case. Also, except for geraniin, all the top-ranked compounds had lower toxicity profiles compared to zafirlukast and this could be attributed to their phenolic moieties. Nevertheless, the in vitro and in vivo confirmation of the activities observed in this study is recommended, especially for maysin and geraniin with the best broad-spectrum activity, towards development of COVID-19 drug candidates.

Astaxanthin-Mediated Bacterial Lethality: Evidence from Oxidative Stress Contribution and Molecular Dynamics Simulation.

The involvement of cellular oxidative stress in antibacterial therapy has remained a topical issue over the years. In this study, the contribution of oxidative stress to astaxanthin-mediated bacterial lethality was evaluated in silico and in vitro. For the in vitro analysis, the minimum inhibitory concentration (MIC) of astaxanthin was lower than that of novobiocin against Staphylococcus aureus but generally higher than those of the reference antibiotics against other test organisms. The level of superoxide anion of the tested organisms increased significantly following treatment with astaxanthin when compared with DMSO-treated cells. This increase compared favorably with those observed with the reference antibiotics and was consistent with a decrease in the concentration of glutathione (GSH) and corresponding significant increase in ADP/ATP ratio. These observations are suggestive of probable involvement of oxidative stress in antibacterial capability of astaxanthin and in agreement with the results of the in silico evaluations, where the free energy scores of astaxanthins' complexes with topoisomerase IV ParC and ParE were higher than those of the reference antibiotics. These observations were consistent with the structural stability and compactness of the complexes as astaxanthin was observed to be more stable against topoisomerase IV ParC and ParE than DNA Gyrase A and B. Put together, findings from this study underscored the nature and mechanism of antibacterial action of astaxanthin that could suggest practical approaches in enhancing our current knowledge of antibacterial arsenal and aid in the novel development of alternative natural topo2A inhibitor.