Corrigendum: Stylopine: a potential natural metabolite to block vascular endothelial growth factor receptor 2 (VEGFR2) in osteosarcoma therapy.

[This corrects the article DOI: 10.3389/fphar.2023.1150270.].

The Involvement of Melatonin and Tasimelteon against Alzheimer's Disease.

BACKGROUND: Alzheimer's disease (AD) is an age-dependent neurodegenerative disease with progressive cognition and memory loss, insomnia, and other abnormal behavioral changes. Amongst various hypotheses for AD pathophysiology, occupational stress-induced Alzheimer's has recently been reported in many AD cases. OBJECTIVE: Studies pertaining to the same suggest that stress leads to insomnia or sleep disruption, which further leads to neuroinflammation due to oxidative stress, both of which are major harbingers of AD. Additionally, overall sleep deficit is associated with progressive cognitive and memory decline, which adds more inconvenience to Alzheimer's disease. Based on this, any triumphant AD management needs a pharmacological intervention that can not only antagonize the amyloid betainduced neurotoxicity but also correct the sleep-wake cycle disruption. Chronobiotic therapeutics like melatonin offer vital neuroprotective effects by eliciting its action through more than one of the pathologies of AD. This is also bolstered by the finding that endogenous melatonin levels are lower in AD patients. This melatonin replacement therapy can be especially useful in AD treatment, but only in the early phases of the disease and in cases where the melatonin receptors are intact and functioning. CONCLUSION: To negate such limitations and extend the action and therapeutic efficacy of melatonin- mediated actions towards AD treatment, melatonin analogue like tasimelteon can pose a high therapeutic value in AD treatment superior to that provided by melatonin. This review encapsulates all details about how AD is believed to occur and how current situations influence it, along with how melatonin and tasimelteon act towards treating Alzheimer's.

Stylopine: A potential natural metabolite to block vascular endothelial growth factor receptor 2 (VEGFR2) in osteosarcoma therapy.

Vascular endothelial growth factor (VEGF) signals cell survival, cell migration, osteogenesis, cell proliferation, angiogenesis, and vascular permeability by binding to VEGF receptor 2 (VEGFR-2). Osteosarcoma is the most common primary bone cancer, majorly affects young adults. Activation of VEGFR-2 signaling is a therapeutic target for osteosarcoma. The present study aimed to evaluate the potency of stylopine in regulation of the VEGFR-2 signaling pathway and its anti-tumour effect human MG-63 osteosarcoma cells. The in silico study on benzylisoquinoline alkaloids was carried out for analyzing and shortlisting of compounds using a virtual screening, Lipinski's rule, bioavailability graphical RADAR plot, pharmacokinetics, toxicity, and molecular docking studies. Among the benzylisoquinoline alkaloids, stylopine was selected and subjected to in-vitro studies against human MG-63 osteosarcoma cells. Various experiments such as MTT assay, EtBr/AO staining, mitochondrial membrane potential assessment, transwell migration assay, gene expression analysis by a quantitative real time polymerase chain reaction (qRT-PCR) method, SDS-PAGE followed by immunoblotting were performed to evaluate its anti-tumour effect as compared to standard axitinib. The MTT assay indicates that stylopine inhibits cell proliferation in MG-63 cells. Similarly, as confirmed by the EtBr/Ao staining method, the MMP assay indicates that stylopine induces mitochondrial membrane damage and apoptosis as compared to axitinib. Moreover, stylopine inhibits the VEGF-165 induced MG-63 cell migration by a trans-well migration assay. The immunoblotting and qRT-PCR analysis showed that stylopine inhibits the VEGF-165 induced VEGFR2 expression in MG-63 cells. It is concluded that stylopine has potential to regulate VEGFR2 and can inhibit osteosarcoma cells to offer a new drug candidate for the treatment of bone cancer in future.