Induction of macrophage cell-cycle arrest and apoptosis by humic acid

Dendrobine modulates autophagy to alleviate ox-LDL-induced oxidative stress and senescence in HUVECs

Dendrobine has potential advantages in suppressing atherosclerosis (AS). FK506-binding protein 1A (FKBP1A) is implicated in the regulation of autophagy, inflammation, and apoptosis. To reveal the mechanism by which dendrobine inhibits AS by modulating autophagy, oxidative stress, apoptosis, and senescence. An in vitro AS cell model was induced by culturing human umbilical vein endothelial cells (HUVECs) with oxidized low-density lipoprotein (ox-LDL). The cells were treated with dendrobine alone or in combination with short hairpin RNA (shRNA) targeting FKBP1A or together with 3-methyladenine (3MA), an autophagy inhibitor. Inflammatory cytokines levels tumor necrosis factor-α, interleukin-6 (IL-6), and IL-1β were analyzed and oxidative stress levels were detected by the analysis of reactive oxygen species, malondialdehyde, and superoxide dismutase levels, followed by the analysis of apoptosis levels through terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Cell senescence was evaluated by senescence-associated β-galactosidase and light chain 3 (LC3) levels were detected by immunofluorescence (IF) staining. The targeting relationship of dendrobine and FKBP1A was predicted by SwissTarget, PyMol, Autodock, and Open Babel software. Dendrobine reduced the levels of proinflammation factors, oxidative stress levels, apoptosis levels, and senescence phenotype in ox-LDL-induced HUVECs. Besides, cell viability has an opposite change. Furthermore, there was an increase in LC3 IF tensity, and LC3-II/I and Beclin1 expressions, and a decrease in p62 expression. However, these effects of dendrobine could be markedly destroyed by shRNA silencing FKBP1A and 3MA. Dendrobine can suppress inflammatory responses, oxidative stress, apoptosis, and senescence via FKBP1A-involved autophagy ox-LDL-treated HUVECs.

Humic Acid Increases Amyloid β-Induced Cytotoxicity by Induction of ER Stress in Human SK-N-MC Neuronal Cells

Humic acid (HA) is a possible etiological factor associated with for several vascular diseases. It is known that vascular risk factors can directly increase the susceptibility to Alzheimer’s disease (AD), which is a neurodegenerative disorder due to accumulation of amyloid β (Aβ) peptide in the brain. However, the role that HA contributes to Aβ-induced cytotoxicity has not been demonstrated. In the present study, we demonstrate that HA exhibits a synergistic effect enhancing Aβ-induced cytotoxicity in cultured human SK-N-MC neuronal cells. Furthermore, this deterioration was mediated through the activation of endoplasmic reticulum (ER) stress by stimulating PERK and eIF2α phosphorylation. We also observed HA and Aβ-induced cytotoxicity is associated with mitochondrial dysfunction caused by down-regulation of the Sirt1/PGC1α pathway, while in contrast, treating the cells with the ER stress inhibitor Salubrinal, or over-expression of Sirt1 significantly reduced loss of cell viability by HA and Aβ. Our findings suggest a new mechanism by which HA can deteriorate Aβ-induced cytotoxicity through modulation of ER stress, which may provide significant insights into the pathogenesis of AD co-occurring with vascular injury.

Synthesis, antitumor activity, and mechanism of action of 6-acrylic phenethyl ester-2-pyranone derivatives

Based on the scaffolds of caffeic acid phenethyl ester (CAPE) as well as bioactive lactone-containing compounds, 6-acrylic phenethyl ester-2-pyranone derivatives were synthesized and evaluated against five tumor cell lines (HeLa, C6, MCF-7, A549, and HSC-2). Most of the new derivatives exhibited moderate to potent cytotoxic activity. Moreover, HeLa cell lines showed higher sensitivity to these compounds. In particular, compound showed potent cytotoxic activity (IC50 = 0.50-3.45 μM) against the five cell lines. Further investigation on the mechanism of action showed that induced apoptosis, arrested the cell cycle at G2/M phases in HeLa cells, and inhibited migration through disruption of the actin cytoskeleton. In addition, ADMET properties were also calculated in silico, and compound showed good ADMET properties with good absorption, low hepatotoxicity, and good solubility, and thus, could easily be bound to carrier proteins, without inhibition of CYP2D6. A structure-activity relationship (SAR) analysis indicated that compounds with ortho-substitution on the benzene ring exhibited obviously increased cytotoxic potency. This study indicated that compound is a promising compound as an antitumor agent.