Biology subjects

Bak, Y.

Publications and source records attributed to Bak, Y..

3 recordsLinked to original sources

bioRxiv2023

Enhanced Omicron subvariant cross-neutralization efficacy of a monovalent SARS-CoV-2 BA.4/5 mRNA vaccine encoding a noncleaved, nonfusogenic spike antigen

The rapid emergence of diverse SARS-CoV-2 variants, notably the Omicron variant, poses challenges to vaccine development. Here, we present a noncleaved, nonfusogenic spike (S) protein eliciting robust B- and T-cell immune responses against Omicron BA.5. The antigen incorporates the R685S and R815A mutations, effectively preventing the shedding of the S1 subunit and eliminating fusogenic activity of the resulting S antigen, termed S(SA). Through reverse genetic analysis, we found that the noncleaved form S protein with the R685S mutation enhances ACE2-dependent viral entry in vitro compared to the wild-type S protein, without increasing the virulence of the mutant virus in mice. The mRNA vaccine encoding the Omicron BA.4/5 S(SA) antigen conferred protective immunity in mice following two doses of 1 g {Psi}-UTP- or UTP-incorporated mRNA vaccines. Despite a roughly 6-fold reduction in neutralizing potency, both mRNA vaccines exhibited broad neutralizing efficacy against Omicron subvariants, including the XBB lineage variants XBB.1.5 and XBB.1.16.

immunology↗

bioRxiv2018

Calotropis gigantea extract induces apoptosis through extrinsic/intrinsic pathways and upregulation of reactive oxygen species in non-small-cell lung cancer cells

BackgroundCalotropis gigantea (CG) plant grows in Asia and tropical Africa. However, the precise mechanisms of its anticancer effects have not yet been examined in human non-small cell lung cancer (NSCLC) cells, A549 and NCI-H1299 cells.\n\nPurposeThis study was focused on the anti-cancer effects of CG extract on non-small cell lung cancer (NSCLC) cells.\n\nMethodsThe cytotoxic effects of CG extract on NSCLC, A549 and NCI-H1299 cells, were detected by MTS assay, microscope and DAPI staining. Apoptosis was determined by annexin V-FITC/PI staining, cell cycle analysis, western blotting, quantitative polymerase chain reaction, and JC-1 staining.\n\nResultsFirst, CG showed significant dose-dependent cytotoxicity in NSCLC, A549, and NCI-H1299 cells. In addition to induction of caspase-8 processing, CG induced apoptosis by upregulating mRNA expression levels of extrinsic pathway molecules such as Fas, Fas ligand (FasL), Fas-associated protein with death domain (FADD) and death receptor 5 (DR5). Also, mitochondrial membrane potential (MMP) was collapsed, and intrinsic pathway molecules such as poly (ADP-ribose) polymerase (PARP), caspase-3, and caspase-9 were processed by CG. Moreover, reactive oxygen species (ROS) were generated in a CG dose-dependent manner, and inhibition of ROS by NAC, ROS scavenger, recovered A549 and NCI-H1299 cell viability.\n\nConclusionThese results indicate that CG causes apoptosis by activating the extrinsic and intrinsic pathways and generating ROS in NSCLC cells. These results suggest that CG can be used as a lung cancer therapeutic agent.

cancer biology↗

bioRxiv2017

(E)-2-Benzylidene-3-(cyclohexylamino)-2,3-dihydro-1H-inden-1-one (BCI) Induces Apoptosis Via The Intrinsic Pathway In H1299 Lung Cancer Cells

(E)-2-benzylidene-3-(cyclohexylamino)-2,3-dihydro-1H-inden-1-one (BCI) is known as a dual specific phosphatase 1/6 or MAPK inhibitor. However, its precise anti-lung cancer mechanism remains unknown. In this study, the effects of BCI on cell viability were investigated in the non-small cell lung cancer cell lines NCI-H1299, A549, and NCI-H460. We confirmed that BCI significantly inhibited the cell viability of NCI-H1299 compared to those of NCI-H460 and A549 cells. The anti-cancer effects of BCI were evaluated by MTS assay, annexin V-fluorescein isothiocyanate/propidium iodide staining, cell cycle analysis, reverse transcription-PCR, western blotting, and JC-1 staining in NCI-H1299 cells. BCI induced cellular morphological changes and inhibited viability of NCI-H1299 cells in a dose-dependent manner. BCI enhanced Bax expression and induced processing of caspase-9, caspase-3, and poly (ADP-ribose) polymerase as well as the release of cytochrome c from the mitochondria into the cytosol. BCI also down-regulated Bcl-2 expression but enhanced Bax expression in a dose-dependent manner in NCI-H1299 cells. In addition, BCI did not modulate death receptor expression or the extrinsic factor caspase-8 and Bid, a linker between the intrinsic and extrinsic apoptotic pathways in NCI-H1299 cells. On the basis of these results, we conclude that BCI induces apoptosis through a mediated intrinsic pathway, but not extrinsic pathway in NCI-H1299 cells. These results suggest that BCI can be used as a therapeutic agent in lung cancer.

pharmacology and toxicology↗