Potential role of vitexin in alleviating heat stress-induced cytotoxicity: Regulatory effect of Hsp90 on ER stress-mediated autophagy

doi:10.1016/j.lfs.2015.10.012

Life Sciences

Volume 142, 1 December 2015, Pages 36-48

https://doi.org/10.1016/j.lfs.2015.10.012 Get rights and content

Abstract

Aims

Cells possess multiple methods for counteracting the deleterious consequences of stress induced by physical and chemical stimuli. Heat stress causes variations in the cellular environment, leading to cellular morbidity or mortality. Natural compounds that contain phenolic antioxidants, offer various therapeutic and biological activities. Vitexin, a natural flavonoid, has been reported to treat various pathologies due to its multifaceted effects. Herein, we investigated the therapeutic efficacy of vitexin and its underlying mechanism against heat stress in human lung epithelial cells.

Main methods

Effect of vitexin on the expression of molecular chaperones, antioxidant enzymes, mitogen activated protein kinases (MAPKs), endoplasmic reticulum (ER)-stress and autophagy was measured by immunoblotting. qRT-PCR and EMSA were performed for Hsp90 expression and HSF-1 binding affinity. Cell viability was assessed by MTT and LDH assays. Detection of autophagy was confirmed by acridine orange staining. Role of Hsp90 inhibition on signaling pathways was elucidated by using specific chemical inhibitor, radicicol.

Key findings

Whereas hyperthermia reduced cell viability, result of MTT and LDH assays showed that vitexin pre-treatment enhanced cell viability after heat stress. EMSA analysis shows DNA binding affinity of HSF-1 during heat stress. Vitexin upregulated Hsp90 expression, subsequently activating ER-stress induced autophagy. Modulation of MAPKs expression and fluorescence image analysis showed vacuole accumulation, indicating autophagic flux in cells. Hsp90 inhibition reversed the effect of vitexin and activates the apoptosis pathway.

Significance

Our data suggest that vitexin can protect against hyperthermic cellular injury by induction of Hsp90 expression, antioxidant activity and MAPKs via ER stress-induced autophagy.

Introduction

All cells and tissues require an optimal temperature range to perform their necessary biological processes. However, cells are under persistent challenge by various environmental and physiological insults, which cause an imbalance in cellular homeostasis [1]. Heat stress (> 43 °C), considered to be an extracellular stimulus, which has multiple causes [2], results in cellular apoptosis or even lethality of entire organisms [3].

The causative molecular events driving heat killing are multifarious. One such causative agent is oxidative stress, which results in reactive oxygen species (ROS) generation, lipid peroxidation, and DNA damage [4], [5]. Additional effects include cytoskeletal defects [6], disruption of plasma membrane structure and function, fragmentation of the endoplasmic reticulum (ER), reduction of lysosome numbers and translational repression [7], [8], [9]. To combat the lethal effects of heat stress, cells have developed a wide array of sophisticated safeguarding mechanisms involving antioxidant enzymes, molecular chaperones, or the lysosomal degradative pathway. Heat shock response (HSR), a universal cytoprotective mechanism, is initiated by activation of heat shock transcription factor (HSF), which stimulates highly conserved heat shock proteins (Hsps) in the cytoplasm. Hsps cope with increased concentrations of thermally denatured proteins by assisting proper refolding as well as alleviation of protein aggregation [10].

During hyperthermia, the ER encounters the same challenges to protein folding as the cytoplasm due to perturbations in Ca^2 + levels as well as altered redox status, resulting in ER stress [11]. The defensive and compensatory mechanism employed in response to ER stress is known as the unfolded protein response (UPR), which is transmitted through three stress receptors, PKR-like ER kinase (PERK), activating transcription factor 6 (ATF6), and inositol-requiring enzyme 1 (IRE1), for restoring ER homeostasis [12]. UPR signaling basically favors cell survival by ameliorating the equilibrium between protein loads and folding magnitude in the ER [13].

Apart from the HSR and UPR, eukaryotic cells employ autophagy, an evolutionary diverse, highly controlled, and orchestrated process, as an alternate defense mechanism to protect against the adverse effects of stress [14]. Autophagy is known as a double-edged sword due to its controversial protective or detrimental role, and is primarily associated with the UPR for removing unfolded proteins to favor survival of stressed cells [15], [16].

Apigenin-8-C-D glucopyranoside (vitexin), is a natural flavonoid compound, and has been reported to exhibit a wide range of pharmacological effects [17], [18], [19], [20], [21]. The seed coat extract of mungbean contains vitexin and isovitexin as major antioxidant components, which can prevent heat stress-induced oxidative injury in rats [22].

In the present report, we attempted to elucidate the underlying effects of vitexin against heat stress-induced cellular injury as well as the multifactorial pathways involved in cellular defense. As hyperthermia is associated with oxidative stress and accumulation of misfolded proteins, we speculated that pre-treatment of A549 cells with vitexin prior to heat stress may augment or inhibit expression of antioxidative enzymes and molecular chaperones, which may affect cell survival during heat injury. Our efforts aimed to assess the regulatory effects of vitexin on cellular defense mechanisms during heat stress via Hsp90 expression mediated through various interacting signaling pathways.

Section snippets

Reagents and antibodies

Vitexin, curcumin, acridine orange (AO), radicicol, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), dichlorodihydrofluorescein diacetate (H₂DCFDA), Actinomycin D (Act D), cycloheximide (CHX) and other chemicals were purchased from Sigma (St. Louis, MO, USA). β-Actin, Hsp70, HSF-1, PERK, GRP78, IRE1-α, p-AMPK, JNK, ERK1/2, p-ERK1/2, p-38, p-p38, Akt, mTOR, p-mTOR, caspase-3, caspase-9, Bax, Bcl-2, Cyt c, catalase, SOD-1, SOD-2, Trx, Prx I/II, glutathione reductase, and

Vitexin defends A549 cells against heat-induced cytotoxicity

To evaluate the cytoprotective role of vitexin against heat-induced cytotoxicity, MTT assay was performed. Active mitochondria in living cells can cleave MTT to form formazan, and the amount produced is directly related to the number of living cells. Significant reduction of cell viability was observed in heat-treated cells as compared to control (Fig. 1A). However, pre-treatment with vitexin substantially increased cell viability in a dose-dependent manner. Curcumin also exhibited a

Discussion

Hyperthermia exceeding 43 °C increases fluidity and disrupts plasma membrane stability, which is an important marker of hyperthermic cell death [32]. During the HSR, stress stimuli activate a set of genes known as Hsps, which maintain cellular homeostasis by functioning as molecular chaperones, resolving protein unfolding, or inhibiting protein damage [33]. Here, we demonstrated the potential role of vitexin against hyperthermia in vitro. Pre-treatment of cells with vitexin before hyperthermia

Conclusion

In summary, this study is the first to demonstrate that the natural flavonoid vitexin plays a cytoprotective role in A549 cells under hyperthermic conditions. We demonstrated that despite down-regulation of HSF-1 and Hsp70, which are hallmarks of cell survival during stress, vitexin confers cytoprotection from the lethal effects of heat stress through up-regulation of Hsp90, antioxidant enzymes, and MAPKs, leading to autophagic cell survival via ER stress-mediated pathways. These findings

Conflict of interest

The authors declare no conflict of interest.

Author contributions

Sun Chul Kang and Souren Paul designed the research study. Monika Bhardwaj, Souren Paul and Rekha Jakhar performed the research. Sun Chul Kang contributed essential reagents or tools. Monika Bhardwaj and Rekha Jakhar interpreted the data. Monika Bhardwaj and Souren Paul drafted the manuscript. All authors read and approved the final manuscript.

Acknowledgments

This research was supported by the Daegu University Research Grant, 2013.

References (68)

C.H. Park et al.
Heat shock-induced matrix metalloproteinase MMP-1 and MMP-3 are mediated through ERK and JNK activation and via an autocrine interleukin-6 loop
J. Investig. Dermatol.
(2004)
S. Matsuki et al.
Suppression of cytochrome c release and apoptosis in testes with heat stress by minocycline
Biochem. Biophys. Res. Commun.
(2003)
D.M. Toivola et al.
Intermediate filaments take the heat as stress proteins
Trends Cell Biol.
(2010)
S. Boulon et al.
The nucleolus under stress
Mol. Cell
(2010)
P. Pallepati et al.
Mild thermotolerance induced at 40 °C protects HeLa cells against activation of death receptor-mediated apoptosis by hydrogen peroxide
Free Radic. Biol. Med.
(2011)
B. Hildebrandt et al.
The cellular and molecular basis of hyperthermia
Crit. Rev. Oncol. Hematol.
(2002)
R. Ahmed et al.
Translational regulation of HSP90 mRNA AUG-proximal 5-untranslated region elements essential for preferential heat shock translation
J. Biol. Chem.
(2004)
A.T. Hoang et al.
A novel association between the human heat shock transcription factor 1 (HSF1) and prostate adenocarcinoma
Am. J. Pathol.
(2000)
S. Khan et al.
Curcumin-induced inhibition of proteasomal activity, enhanced HSP accumulation and the acquisition of thermotolerance in Xenopus laevis A6 cells
Comp. Biochem. Phys. A
(2011)
A. Tanel et al.
Acrolein activates cell survival and apoptotic death responses involving the endoplasmic reticulum in A549 lung cells
Biochim. Biophys. Acta
(2014)

Y. Wang et al.

Activation of ATF6 and an ATF6 DNA binding site by the endoplasmic reticulum stress response

J. Biol. Chem.

(2000)

Y.S. Tarahovsky et al.

Flavonoid-membrane interactions: involvement of flavonoid-metal complexes in raft signaling

BBA-Biomembranes

(2014)

J. Kang et al.

Anti-oxidant capacities of flavonoid compounds isolated from acai pulp (Euterpe oleracea Mart.)

Food Chem.

(2010)

E.L. Robb et al.

Molecular mechanisms of oxidative stress resistance induced by resveratrol: specific and progressive induction of MnSOD

Biochem. Biophys. Res. Commun.

(2008)

P.A. Baeuerle

Inducible gene expression. Vol. I. Environmental stresses and nutrients Vol. II.

D. Nowak et al.

Protective effect of ambroxol against heat- and hydrogen peroxide-induced damage to lung lipids in mice

Eur. Respir. J.

(1994)

J.F. Davidson et al.

Cytotoxic and genotoxic consequences of heat stress are dependent on the presence of oxygen in Saccharomyces cerevisiae

J. Bacteriol.

(2001)

W.J. Welch et al.

Morphological study of the mammalian stress response: characterization of changes in cytoplasmic organelles, cytoskeleton, and nucleoli, and appearance of intranuclear actin filaments in rat fibroblasts after heat-shock treatment

J. Cell Biol.

(1985)

I.S. Kim et al.

Heat shock causes oxidative stress and induces a variety of cell rescue proteins in Saccharomyces cerevisiae KNU5377

J. Microbiol.

(2006)

K.C. Kregel

Heat shock proteins: modifying factors in physiological stress responses and acquired thermotolerance

J. Appl. Physiol.

(1985, 2002)

X. Xu et al.

Hyperthermia induces the ER stress pathway

PLoS One

(2011)

S. Fulda et al.

Cellular stress responses: cell survival and cell death

Int. J. Cell Biol.

(2010)

O. Hori et al.

Deletion of SERP1/RAMP4, a component of the endoplasmic reticulum (ER) translocation sites, leads to ER stress

Mol. Cell. Biol.

(2006)

D.C. Rubinsztein et al.

Autophagy modulation as a potential therapeutic target for diverse diseases

Nat. Rev. Drug Discov.

(2012)

E.H. Baehrecke

Autophagy: dual roles in life and death?

Nat. Rev. Mol. Cell Biol.

(2005)

Y. Cheng et al.

Survival and death of endoplasmic-reticulum-stressed cells: role of autophagy

World J. Biol. Chem.

(2011)

S.J. Lee et al.

Effect of mung bean ethanol extract on pro-inflammatory cytokines in LPS stimulated macrophages

Food Sci. Biotechnol.

(2011)

E. Farsi et al.

Correlation between enzymes inhibitory effects and antioxidant activities of standardized fractions of methanolic extract obtained from Ficus deltoidea leaves

Afr. J. Biotechnol.

(2011)

J. Kim et al.

Vitexin, orientin and other flavonoids from Spirodela polyrhiza inhibit adipogenesis in 3T3-L1 cells

Phytother. Res.

(2010)

E. Gaitan et al.

Antithyroid effects in vivo and in vitro of vitexin: a C-glucosylflavone in millet

J. Clin. Endocrinol. Metab.

(1995)

Z. Tan et al.

Purified vitexin compound 1 suppresses tumor growth and induces cell apoptosis in a mouse model of human choriocarcinoma

Int. J. Gynecol. Cancer

(2012)

D. Cao et al.

Antioxidant properties of the mung bean flavonoids on alleviating heat stress

PLoS One

(2011)

J.F. Pittet et al.

Stress preconditioning attenuates oxidative injury to the alveolar epithelium of the lung following haemorrhage in rats

J. Physiol.

(2002)

S.H. Weng et al.

Enhancement of mitomycin C-induced cytotoxicity by curcumin results from down-regulation of MKK1/2-ERK1/2-mediated thymidine phosphorylase expression

Basic Clin. Pharmacol. Toxicol.

(2012)

Cited by (29)

Pre-treatment but not co-treatment with vitexin alleviates hyperthermia induced oxidative stress and inflammation in buffalo mammary epithelial cells
2023, Journal of Reproductive Immunology
This study investigated if in vitro supplementation of vitexin could mitigate the adverse effects of hyperthermia on buffalo mammary epithelial cells (BuMECs). Immortalized BuMECs were divided into seven groups (n = 3): (1) a negative control group at 37 °C; (2) BuMECs exposed to heat stress as a positive control at 42 °C for 1 h; (3−7) heat stressed BuMECs pre-treated or co-treated with different concentrations of vitexin (5 μM, 10 μM, 20 μM, 50 μM, and 100 μM), respectively. Hyperthermia was induced by exposing the cells to 42 ºC for 1 h. For the pre-treatment experiment, BuMECs were treated with vitexin for 2 h before hyperthermia exposure. For co-treatment, vitexin was added simultaneously with hyperthermia for 1 h. Subsequently, the cells were allowed to recover for 12 h at 37 °C. Results showed that pre-treatment with vitexin was more effective than co-treatment in protecting BuMECs from hyperthermia in a dose-dependent manner, with higher concentrations (50 μM and 100 μM) being the most effective. Pre-treatment with vitexin maintained cellular viability and prevented inflammation by inducing the expression of the anti-apoptotic gene (BCL-2) and reducing the expression of the pro-apoptotic gene (Bax) and pro-inflammatory mediators (IL-1β, IL-6) in heat-stressed BuMECs. Pre-treatment with vitexin reduced oxidative stress and induced thermotolerance by increasing the expression of antioxidants mediators such as SOD, GPx and CAT at mRNA and protein levels, and modulating the expression of heat shock proteins. The findings suggest that vitexin has the potential as a therapeutic agent to protect the mammary gland from the negative impact of hyperthermia in dairy cows.
Secreted heat shock proteins control airway remodeling: Evidence from bronchial thermoplasty
2021, Journal of Allergy and Clinical Immunology
Increased airway smooth muscle mass is a key pathology in asthma. Bronchial thermoplasty is a treatment for severe asthma based on selective heating of the airways that aims to reduce the mass of airway smooth muscle cells (ASMCs), and thereby bronchoconstriction. However, short heat exposure is insufficient to explain the long-lasting effect, and heat shock proteins (HSPs) have been suggested to play a role.
We sought to determine the role of HSP70 and HSP90 in the control of airway wall remodeling by bronchial thermoplasty.
Bronchoalveolar lavage fluid and endobronchial biopsies of 20 patients with severe asthma were obtained before and after thermoplasty. Isolated epithelial cells and ASMCs were exposed to 65^oC for 10 seconds, mimicking thermoplasty. Proteins were determined by immunohistochemistry, Western blotting, immunofluorescence, and ELISA; proliferation by cell counts and antigen Ki67 (MKI67) expression.
Thermoplasty significantly increased the expression of HSP70 and HSP90 in the epithelium and bronchoalveolar lavage fluid. In ASMCs, thermoplasty reduced both HSPs. These cell-type–specific effects were detectable even 1 month after thermoplasty in tissue sections. In epithelial cells, ex vivo exposure to heat (65^oC, 10 seconds) increased the expression and secretion of HSP70 and HSP90. In addition, epithelial cell proliferation was upregulated by heat or treatment with human recombinant HSP70 or HSP90. In ASMCs, heat exposure or exogenous HSPs reduced proliferation and differentiation. In both cell types, HSP70 and HSP90 activated the signaling cascade of serine/threonine-protein kinase →mammalian target of rapamycin→ribosomal protein S6 kinase 1 and CCAAT/enhancer binding protein-β→protein arginine methyltransferase 1→ mitochondria activity.
Epithelial cell–derived HSP70 and HSP90 improve the function of epithelial cells, but block ASMC remodeling.
Ficus deltoidea: Potential inhibitor of pro-inflammatory mediators in lipopolysaccharide-induced activation of microglial cells
2021, Journal of Ethnopharmacology
Ficus deltoidea Jack (FD) is widely consumed in traditional medicine as a treatment for various diseases in Malaysia. Each part of the plant such as its leave, stem, fruit and root are used traditionally to treat different types of diseases. Vitexin and isovitexin are bioactive compounds abundantly found in the leaves of FD that possessed many pharmacological properties including neuroprotection. Nonetheless, its effects on key events in neuroinflammation are unknown.
Aim of the study: To determine the inhibitory properties of FD aqueous extract on pro-inflammatory mediators involved in lipopolysaccharide (LPS)-induced microglial cells.
Vitexin and isovitexin in the extract were quantified via high performance liquid chromatography (HPLC). The extract was evaluated for its cytotoxicity activity via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Pre-treatment with the extract on LPS-induced microglial cells was done to determine its antioxidant and anti-neuroinflammatory properties by measuring the level of reactive oxygen species (ROS), nitric oxide (NO), tumour necrosis factor alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) via 2′-7′-dichlorofluorescin diacetate (DCFDA) assay, Griess assay and Western blot respectively.
The extract at all tested concentrations (0.1 μg/mL, 1 μg/mL, 10 μg/mL, 100 μg/mL) were not cytotoxic as the percentage viability of microglial cells were all above ~80%. At the highest concentration (100 μg/mL), the extract significantly reduced the formation of ROS, NO, TNF-α, IL-1β and IL-6 in microglial cells induced by LPS.
The extract showed neuroprotective effects by attenuating the levels of pro-inflammatory and cytotoxic factors in LPS-induced microglial cells, possibly by mediating the nuclear factor-kappa B (NF-κB) signalling pathway.
Insulin ameliorates hypoxia-induced autophagy, endoplasmic reticular stress and apoptosis of myocardial cells: In vitro and ex vivo models
2020, European Journal of Pharmacology
Citation Excerpt :
The intensity of autophagy was reflected in the mean fluorescence intensity (MFI) of each sample. The characteristic vesicles of autophagy can be additionally quantified using fluorescence staining with a weak base, acridine orange (AO) (ImmunoChemistry Technologies, Bloomington, MN, USA), which accumulates in acidic spaces, including autophagosomes and lysosomes, and presents coloration (Bhardwaj et al., 2015). For this assay, cardiomyocytes (1 × 106) cultured in 24-well culture plates were added with 0.5 μM AO for 30 min and then analyzed using fluorescence microscopy with an ELISA reader with 540 nm excitation and 590 nm emission filters.
Whether and how insulin counteracts the cytotoxic effects of hypoxia and improves cardiomyocyte viability remains unclear. To achieve this aim, cultured neonatal rat cardiomyocytes pretreated with vehicle or 1 μM insulin were exposed to either normoxic or hypoxia environment for up to 24 h. Cell viability was monitored and cellular apoptosis as well as necrosis, indexes of autophagy, endoplasmic reticular (ER) stress, and expressions of specific relevant mediators of the signaling pathways of autophagy were also assessed. Hypoxia impaired cell viability, induced autophagy, triggered apoptosis, activated ER stress pathway-associated apoptotic responses along with downstream pro-apoptotic transcriptional factor C/EBP homologous protein (CHOP), and increased apoptosis of myocardial cells. On the other hand, insulin pretreatment effectively ameliorated autophagy via PI3–K/Akt signaling pathway, suppressed ER stress, and prevented hypoxia-induced cellular apoptosis. In an ex vivo study, isolated rat hearts were pre-treated in some cases with insulin and subjected to proximal left coronary artery ligation to induce acute myocardial ischemia. Coronary ligation-induced acute ischemia upregulated glucose-related protein 78 (GRP78) and triggered cellular apoptosis in the jeopardized myocardium. Conversely, insulin pretreatment suppressed these hypoxia-related cytotoxic events and reduced myocardial infarct size by up to 15.2%. In conclusion, hypoxia impedes cell viability through triggering autophagy, ER stress and apoptosis, whereas insulin pretreatment effectively prevents these cytotoxic actions of hypoxia, preserves myocardial cell viability and reduces myocardial infarct size. These results indicated the cytoprotective mechanism of insulin against the insult of hypoxia may justify insulin as a therapeutic option for patients with acute myocardial infarction.
Binding interaction of N-acetylated acridine conjugate with ct-DNA and β-cyclodextrin: Synthesis and photophysical studies
2018, Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
Citation Excerpt :
The hydrophobic tail of AC-PA, increased the hydrophobicity of AC-PA and thus AC-PA shows better hydrophobic interaction with hydrophobic ct-DNA. A linear Stern–Volmer plot suggests that only one type of binding or quenching process is occurring in the systems (Fig. 3) [17]. Time-resolved fluorescence experiment is one of the important and specific methods to understand the mechanism of quenching (static or dynamic quenching) [18].
In the present work we are reporting the synthesis and binding interaction of a saturated fatty acid containing 9-aminoacridine derivative (AC-PA) with ct-DNA and β-cyclodextrin (β-CD). From Steady-state fluorescence experiments this newly synthesized 9-aminoacridine derivative, AC-PA, shows more efficient binding interaction with ct-DNA as compared to the 9-aminoacridine (AC). The extent of interaction of AC-PA and AC with ct-DNA was found out by calculating the fluorescence quenching by using Stern–Volmer quenching equation. The calculated quenching constants of AC-PA and AC are (4.5 ± 0.5) × 10³M⁻¹ (3.7 ± 0.5) × 10³M⁻¹ respectively. The mechanism of fluorescence quenching of AC-PA and AC, were understand by using Stern–Volmer plots as well as time-resolved fluorescence experiments. The fluorescence quenching of AC-PA and AC by ct-DNA are static in nature and take place by formation of ground state complexes. The binding mode between AC-PA and AC were understood by DNA melting analysis experiment. The DNA melting analysis experiments were reveals that the binding interactions between fluorophores (AC-PA and AC) with ct-DNA are intercalative in nature. The melting temperature and mode of binding intercalative mode of binding between AC-PA and AC were further confirmed by DSC and CD experiments. The steady-state and time-resolved fluorescence parameters of AC-PA are quite sensitive towards the formation of inclusion complexes between AC-PA and β-CD. Long hydrophobic tail containing acridine conjugate (AC-PA) shows more efficient binding interactions with the β-CD and the calculated binding constants value of AC-PA is 0.51 × 10²M⁻¹. Whereas, the parent molecule, AC not showing any binding interactions with β-CD.
Novel vitexin-inspired scaffold against leukemia
2018, European Journal of Medicinal Chemistry
Citation Excerpt :
While several leukemia cellular models were utilized for our viability assays, we focused our attention on compounds with cytotoxicity against a particular subset of acute lymphoblastic leukemia: KOPN-8, SEM, and SUP-B15 models, all of which carry specific genomic lesions. KOPN-8 carries the MLL-ENL fusion gene, SEM is a carrier of t(4, 11) fusion gene (MLL-AF4), and SUP-B15 was established from a pediatric ALL relapsed patient (with the m-BCR ALL variant of the BCR-ABL1 fusion gene) [14]. The gene for the histone methyltransferase MLL participates in chromosomal translocations that eventually create MLL-fusion proteins associated with very aggressive forms of childhood acute leukemia.
Acute lymphoblastic leukemia (ALL) is the most common type of leukemia in children. Up to a quarter of ALL patients relapse and face poor prognosis. To identify new compound leads, we conducted a phenotypic screen using terrestrial natural product (NP) fractions against immortalized ALL cellular models.
We identified vitexin, a flavonoid, as a promising hit with biological activity (EC₅₀ = 30 μM) in pre-B cell ALL models with no toxicity against normal human tissue (BJ cells) at the tested concentrations. To develop more potent compounds against ALL and elucidate its potential mode of action, a vitexin-inspired compound library was synthesized. Thus, we developed an improved and scalable protocol for the direct synthesis of 4-quinolone core heterocycles containing an N-sulfonamide using a one-pot condensation reaction protocol. The newly generated compounds represent a novel molecular scaffold against ALL as exemplified by compounds 13 and 15, which demonstrated EC₅₀ values in the low micromolar range (0.3–10 μM) with little to no toxicity in normal cellular models. Computational studies support the hypothesis that these compounds are potential CDK inhibitors. The compounds induced apoptosis, caused cell arrest at G0/G1 and G2/M, and induced ROS in cancer cells.

View all citing articles on Scopus

View full text

Potential role of vitexin in alleviating heat stress-induced cytotoxicity: Regulatory effect of Hsp90 on ER stress-mediated autophagy

Abstract

Aims

Main methods

Key findings

Significance

Introduction

Section snippets

Reagents and antibodies

Vitexin defends A549 cells against heat-induced cytotoxicity

Discussion

Conclusion

Conflict of interest

Author contributions

Acknowledgments

J. Investig. Dermatol.

Biochem. Biophys. Res. Commun.

Trends Cell Biol.

Mol. Cell

Free Radic. Biol. Med.

Crit. Rev. Oncol. Hematol.

J. Biol. Chem.

Am. J. Pathol.

Comp. Biochem. Phys. A

Biochim. Biophys. Acta

J. Biol. Chem.

BBA-Biomembranes

Food Chem.

Biochem. Biophys. Res. Commun.

Inducible gene expression. Vol. I. Environmental stresses and nutrients Vol. II.

Protective effect of ambroxol against heat- and hydrogen peroxide-induced damage to lung lipids in mice

Eur. Respir. J.

Cytotoxic and genotoxic consequences of heat stress are dependent on the presence of oxygen in Saccharomyces cerevisiae

J. Bacteriol.

Morphological study of the mammalian stress response: characterization of changes in cytoplasmic organelles, cytoskeleton, and nucleoli, and appearance of intranuclear actin filaments in rat fibroblasts after heat-shock treatment

J. Cell Biol.

Heat shock causes oxidative stress and induces a variety of cell rescue proteins in Saccharomyces cerevisiae KNU5377

J. Microbiol.

Heat shock proteins: modifying factors in physiological stress responses and acquired thermotolerance

J. Appl. Physiol.

Hyperthermia induces the ER stress pathway

PLoS One

Cellular stress responses: cell survival and cell death

Int. J. Cell Biol.

Deletion of SERP1/RAMP4, a component of the endoplasmic reticulum (ER) translocation sites, leads to ER stress

Mol. Cell. Biol.

Autophagy modulation as a potential therapeutic target for diverse diseases

Nat. Rev. Drug Discov.

Autophagy: dual roles in life and death?

Nat. Rev. Mol. Cell Biol.

Survival and death of endoplasmic-reticulum-stressed cells: role of autophagy

World J. Biol. Chem.

Effect of mung bean ethanol extract on pro-inflammatory cytokines in LPS stimulated macrophages

Food Sci. Biotechnol.

Correlation between enzymes inhibitory effects and antioxidant activities of standardized fractions of methanolic extract obtained from Ficus deltoidea leaves

Afr. J. Biotechnol.

Vitexin, orientin and other flavonoids from Spirodela polyrhiza inhibit adipogenesis in 3T3-L1 cells

Phytother. Res.

Antithyroid effects in vivo and in vitro of vitexin: a C-glucosylflavone in millet

J. Clin. Endocrinol. Metab.

Purified vitexin compound 1 suppresses tumor growth and induces cell apoptosis in a mouse model of human choriocarcinoma

Int. J. Gynecol. Cancer

Antioxidant properties of the mung bean flavonoids on alleviating heat stress

PLoS One

Stress preconditioning attenuates oxidative injury to the alveolar epithelium of the lung following haemorrhage in rats

J. Physiol.

Enhancement of mitomycin C-induced cytotoxicity by curcumin results from down-regulation of MKK1/2-ERK1/2-mediated thymidine phosphorylase expression

Basic Clin. Pharmacol. Toxicol.