HeLa Cell Death Research Articles

Anticancer potential of AgNPs synthesized using Acinetobacter sp. and Curcuma aromatica against HeLa cell lines: A comparative study

BackgroundBiogenic nanoparticles are gaining attention due to their low toxicity and numerous biomedical applications. Present study aimed to compare the potential anticancer activity of two biogenic silver nanoparticles (bAgNPs and pAgNPs) against human cervical cancer cell lines (HeLa). MethodsbAgNPs were synthesized using Acinetobacter sp. whereas pAgNPs were synthesized using aqueous root extract of Curcuma aromatica. Effect of these nanoparticles on HeLa cells viability was studied using MTT assay and colony formation assay. Anticancer potential was determined using fluorescence microscopy and flow cytometry studies. Bio-compatibility studies were performed against peripheral blood mononuclear cells (PBMCs). ResultsBoth the nanoparticles showed 50 % viability of peripheral blood mononuclear cells (PBMCs) when used at high concentration (200 μg/mL). IC50 for bAgNPs and pAgNPs against HeLa cells were 17.4 and 14 μg/mL respectively. Colony formation ability of Hela cells was reduced on treatment with both nanoparticles. Acridine orange and ethidium bromide staining demonstrated that bAgNPs were cytostatic whereas pAgNPs were apoptotic. JC-1 dye staining revealed that the mitochondrial membrane potential was affected on treatment with pAgNPs while it remained unchanged on bAgNPs treatment. Flow cytometry confirmed cell cycle arrest in HeLa cells on treatment with nanoparticles further leading to apoptosis in case of pAgNPs. About 77 and 58 % HeLa cells were found in subG1 phase on treatment with bAgNPs and pAgNPs respectively. bAgNPs showed cytostatic effect on HeLa cells arresting the cell growth in subG1 phase, whereas, pAgNPs triggered death of HeLa cells through mitochondrial membrane potential impairment and apoptosis. ConclusionOverall, bAgNPs and pAgNPs could be safe and showed potential to be used as anticancer nano-antibiotics against human cervical cancer cells.

IMMUNEPOTENT CRP induces DAMPS release and ROS-dependent autophagosome formation in HeLa and MCF-7 cells

BackgroundIMMUNEPOTENT CRP (ICRP) can be cytotoxic to cancer cell lines. However, its widespread use in cancer patients has been limited by the absence of conclusive data on the molecular mechanism of its action. Here, we evaluated the mechanism of cell death induced by ICRP in HeLa and MCF-7 cells.MethodsCell death, cell cycle, mitochondrial membrane potential and ROS production were evaluated in HeLa and MCF-7 cell lines after ICRP treatment. Caspase-dependence and ROS-dependence were evaluated using QVD.oph and NAC pre-treatment in cell death analysis. DAMPs release, ER stress (eIF2-α phosphorylation) and autophagosome formation were analyzed as well. Additionally, the role of autophagosomes in cell death induced by ICRP was evaluated using SP-1 pre-treatment in cell death in HeLa and MCF-7 cells.ResultsICRP induces cell death, reaching CC50 at 1.25 U/mL and 1.5 U/mL in HeLa and MCF-7 cells, respectively. Loss of mitochondrial membrane potential, ROS production and cell cycle arrest were observed after ICRP CC50 treatment in both cell lines, inducing the same mechanism, a type of cell death independent of caspases, relying on ROS production. Additionally, ICRP-induced cell death involves features of immunogenic cell death such as P-eIF2α and CRT exposure, as well as, ATP and HMGB1 release. Furthermore, ICRP induces ROS-dependent autophagosome formation that acts as a pro-survival mechanism.ConclusionsICRP induces a non-apoptotic cell death that requires an oxidative stress to take place, involving mitochondrial damage, ROS-dependent autophagosome formation, ER stress and DAMPs’ release. These data indicate that ICRP could work together with classic apoptotic inductors to attack cancer cells from different mechanisms, and that ICRP-induced cell death might activate an immune response against cancer cells.

Synthesis of Silver Nanoparticles using Euphorbia wallichii Extract and Assessment of their Bio-functionalities.

Silver nanoparticles synthesized by the bio-green method have been applied to various biomedical applications. These procedures are simple, eco-friendly and serve as an alternative to complex chemical methods for the preparation of nanomaterials. In the present study, phytosynthesis of silver nanoparticles, to examine their antioxidant potential, toxic effects towards bacterial-, fungal-strains, brine shrimp nauplii and cancer cells was focused. Methanolic extract of Euphorbia wallichii roots was used for the synthesis of silver nanoparticles. The synthesis was monitored and confirmed by UV-visible spectroscopy, Fourier Transform Infra-Red (FTIR) spectrometric analysis, Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray (EDX) and X-Ray Powder Diffraction (XRD). The synthesized particles were average 63±8 nm in size. Involvement of phenolic (46.7±2.4 µg GAE/mg) and flavonoid (11.7±1.2 µg QE/mg) compounds as capping agents was also measured. Nanoparticles showed antioxidant properties in terms of free radical scavenging potential (59.63±1.0 %), reducing power (44.52±1.34 µg AAE/mg) and total antioxidant capacity (60.48±2.2 µg AAE/mg). The nanoparticles showed potent cytotoxic effects against brine shrimp nauplii (LD50 66.83 µg/ml), proliferation and cell death of HeLa cells as determined by MTT (LD50 0.3923 µg/ml) and TUNEL assays, respectively. Antimicrobial results revealed that silver nanoparticles were found to be more potent against pathogenic fungal (maximum active against A. fumigatus, MIC 15 µg/disc) and bacterial strains (maximum active against S. aureus, MIC 3.33 μg/disc) than the E. wallichii extract alone. These results support the advantages of using an eco-friendly and cost-effective method for synthesis of nanoparticles with antioxidant, cytotoxic and antimicrobial potential.

Simultaneous Control of Endogenous and User-Defined Genetic Pathways Using Unique ecDHFR Pharmacological Chaperones

Destabilizing domains (DDs), such as a mutated formof Escherichia coli dihydrofolate reductase (ecDHFR), confer instability and promote protein degradation. However, when combined with small-molecule stabilizers (e.g., the antibiotic trimethoprim), DDs allow positive regulation of fusion proteinabundance. Using a combinatorial screening approach, we identified and validated 17unique 2,4-diaminopyrimidine/triazine-based ecDHFR DD stabilizers, at least 15 of which were ineffective antibiotics against E. coli and S. aureus. Identified stabilizers functioned invivo to control an ecDHFR DD-firefly luciferase in the mouse eye and/or the liver. Next, stabilizers were leveraged to perform synergistic dual functions invitro (HeLa cell death sensitization) and invivo (repression of ocular inflammation) by stabilizing a user-defined ecDHFR DD while also controlling endogenous signaling pathways. Thus, these newly identified pharmacological chaperones allow for simultaneous control of compound-specific endogenous and user-defined genetic pathways, the combination of which may provide synergistic effects in complex biological scenarios.

Involvement of protein disulfide isomerase in subtilase cytotoxin-induced cell death in HeLa cells

Subtilase cytotoxin (SubAB) is a member of bacterial AB5 toxin produced by certain enterohemorrhagic E. coli strains which cleaves host chaperone BiP in endoplasmic reticulum (ER), leading to ER stress-mediated cytotoxicity. Previous study suggested that protein disulfide isomerase (PDI), an enzyme which catalyzes the formation and breakage of disulfide bonds in proteins, regulates AB5 toxin such as cholera toxin by unfolding of A subunit, leading to its translocation into cytosol to induce disease. Although SubAB targets ER and has similar A subunit to that of other AB5 toxins, it is unclear whether PDI can modulate the SubAB function. Here we determined the role of PDI on SubAB-induced BiP cleavage, ER stress response and cytotoxicity in HeLa cells. We found that PDI knockdown significantly suppressed SubAB-induced BiP cleavage and eIF2α phosphorylation. The accumulation of SubAB in ER was perturbed upon PDI knockdown. Finally, cell viability assay showed that PDI knockdown and PDI inhibitor canceled the SubAB-induced cytotoxicity. Present results suggested that SubAB, after cellular uptake, translocates into ER and interacts with BiP that might be modulated by PDI. Identification of pivotal role of host proteins on bacterial toxin to elicit its pathogenesis is necessary basis for development of potential chemotherapy and new diagnostic strategy for control of toxin-producing bacterial infections.

The Photorhabdus Virulence Cassettes RRSP-Like Effector Interacts With Cyclin-Dependent Kinase 1 and Causes Mitotic Defects in Mammalian Cells.

The “Photorhabdus virulence cassettes” (PVCs) secreted by Photorhabdus are defined as “extracellular contractile injection systems” (eCISs) and can deliver effectors to eukaryotic hosts for cytotoxicity. Previously, we demonstrated the cryogenic electron microscopy (cryo-EM) structure and assembly process of an intact PVC particle from Photorhabdus asymbiotica. In this work, we characterized the biological functions of a PVC effector, which is defined as a homologous protein of Ras/Rap1-specific endopeptidase domain (RRSP) in the multifunctional autoprocessing repeats-in-toxin (MARTX) toxin from Vibrio vulnificus. In this work, we found that the RRSP homologous protein (RRSPPa) was associated with inhibition of cell proliferation and increased cell apoptosis and death of HeLa cells. Furthermore, we discovered that RRSPPa disturbed mitotic progression, including the induction of cell cycle alteration, retardation of cell abscission time, and regression of the cleavage furrow. In addition, we revealed that RRSPPa could target the cyclin-dependent kinase 1 (CDK1) protein and block activation of CDK1 through inhibition of Thr161 phosphorylation, which partially explained the crucial role of this effector in cell mitosis.

Synthesis of novel dimeric compounds containing triazole using click method and their selective antiproliferative and proapoptotic potential via mitochondrial apoptosis signaling

In this study, the main aim was synthesis of dimeric compounds, which contain lithocholic acid and a triazole structure to investigate the selective cellular and molecular antiproliferative and proapoptotic potential of these products in healthy embryonic fibroblast (MEF), cervix cancer (HeLa), and breast cancer (MCF-7) cells. Four ester (5a–d) and five dimeric (6a–d, 7) out of nine novel compounds were obtained. First of all, lithocholic acid was converted to methyl lithocholate and then it was reacted with certain alkynoic acids (a–d) to obtain its alkynoate derivatives (5a–d). Finally, these compounds were converted to dimers (6a–d) by using 2,6-bis(azidomethyl)pyridine via the click method. Our result indicate that, treatment with dimeric compounds can selectively decrease the cell viability and proliferation in cervix cancer HeLa and breast cancer MCF-7 cells, except 7 which caused a strong cytotoxicity on healthy MEF cells. According to MTT assay, Nucblue cell stain and Annexin V/Propodium iodide molecular probe staining, 100 µM concentrations of the dimeric compounds was sufficient in inducing death and apoptotic cell ratio in HeLa and MCF-7 breast cancer cells selectively. In brief, the present study indicates that most effective dimeric compounds are 6a and 6b, which have the highest IC50 (345.8–342.6 µM) value on healthy cell and the lowest IC50 value in both cervix (49.2–36.9 µM) and breast (23.0–66.1 µM) cancer cells especially long-term treatment and which triggers apoptosis pathway specifically.

Genome-scale CRISPR screening for potential targets of ginsenoside compound K

Ginsenosides exhibit a large variety of biological activities in maintaining physical health; however, the molecule underpinnings underlining these biological activities remain to be defined. Here, we took a cellular condition that compound K (CK) induces autophagic cell death in HeLa cells, and setup a high-throughput genetic screening using CRISPR technology. We have identified a number of CK-resistant and CK-sensitive genes, and further validated PMAIP1 as a CK-resistant gene and WASH1 as a CK-sensitive gene. Compound K treatment reduces the expression of WASH1, which further accelerates the autophagic cell death, highlighting WASH1 as an interesting downstream mediator of CK effects. Overall, our study offers an easy-to-adopt platform to study the functional mediators of ginsenosides, and provides a candidate list of genes that are potential targets of CK.

A water-soluble pyrazino[2,3-g]quinoxaline photosensitizer for high-efficiency one- and two-photon excited bioimaging and photodynamic therapy.

A water-soluble photosensitizer, PQs-PEG5, based on a novel pyrazino[2,3-g]quinoxaline (PQ) prototype compound (PQs-5), was designed and synthesized. It has strong linear absorption within 400-600 nm and a desirable two-photon absorption cross section (100-1290 GM) within 740-1000 nm, and it exhibits both a high fluorescence quantum yield (∼0.55) and singlet oxygen quantum yield (∼0.47). By carrying out in vitro cell imaging and photodynamic therapy (PDT) experiments on PQs-PEG5 with HeLa and 4T1 cells, it was demonstrated that PQs-PEG5 can present outstanding bioimaging performance and PDT efficacies simultaneously. Under one-photon excitation (1PE) of a 635 nm diode laser (60 mW cm-2, 5 min) or two-photon excitation (2PE) of an 820 nm fs laser (100 mW, 80 MHz, 140 fs, 5 min), PQs-PEG5 (10 μM) could cause HeLa and 4T1 cell death effectively, which indicated its great potential as a novel photosensitizer for both 1PE- and 2PE-PDT applications.

Insights into the antiproliferative mechanism of (C^N)-chelated half-sandwich iridium complexes.

Transition metal-based anticancer compounds, as an alternative to platinum derivatives, are raising scientific interest as they may present distinct although poorly understood mechanisms of action. We used a structure-activity relationship-based methodology to investigate the chemical and biological features of a series of ten (C^N)-chelated half-sandwich iridiumIII complexes of the general formula [IrCp*(phox)Cl], where (phox) is a 2-phenyloxazoline ligand forming a 5-membered metallacycle. This series of compounds undergoes a fast exchange of their chlorido ligand once solubilised in DMSO. They were cytotoxic to HeLa cells with IC50 values in the micromolar range and induced a rapid activation of caspase-3, an apoptosis marker. In vitro, the oxidative power of all the complexes towards NADH was highlighted but only the complexes bearing substituents on the oxazoline ring were able to produce H2O2 at the micromolar range. However, we demonstrated using a powerful HyPer protein redox sensor-based flow cytometry assay that most complexes rapidly raised intracellular levels of H2O2. Hence, this study shows that oxidative stress can partly explain the cytotoxicity of these complexes on the HeLa cell line and gives a first entry to their mechanism of action.

Excessive ER-phagy mediated by the autophagy receptor FAM134B results in ER stress, the unfolded protein response, and cell death in HeLa cells

Autophagy is typically a prosurvival cellular process that promotes the turnover of long-lived proteins and damaged organelles, but it can also induce cell death. We have previously reported that the small molecule Z36 induces autophagy along with autophagic cell death in HeLa cells. In this study, we analyzed differential gene expression in Z36-treated HeLa cells and found that Z36-induced endoplasmic reticulum-specific autophagy (ER-phagy) results in ER stress and the unfolded protein response (UPR). This result is in contrast to the common notion that autophagy is generally activated in response to ER stress and the UPR. We demonstrate that Z36 up-regulates the expression levels of FAM134B, LC3, and Atg9, which together mediate excessive ER-phagy, characterized by forming increased numbers of autophagosomes with larger sizes. We noted that the excessive ER-phagy accelerates ER degradation and impairs ER homeostasis and thereby triggers ER stress and the UPR as well as ER-phagy-dependent cell death. Interestingly, overexpression of FAM134B alone in HeLa cells is sufficient to impair ER homeostasis and cause ER stress and cell death. These findings suggest a mechanism involving FAM134B activity for ER-phagy to promote cell death.

Induction of endomitosis-like event in HeLa cells following CHK1 inhibitor treatment

The effects of CHK1 inhibitor on cell cycle kinetics have not been fully investigated yet. In this study, we closely analyzed this kinetics using a CHK1 inhibitor (PF00477736) in HeLa cells expressing fluorescent ubiquitination-based cell cycle indicator (Fucci). This system allowed us to visualize cell cycle progression following CHK1 inhibitor treatment in real-time. FACS analysis showed that high levels of DNA damage as determined by γH2AX immunostaining was induced in S phase and that polyploid cells harboring the same levels of DNA damage appeared thereafter. Surprisingly, time-lapse imaging of Fucci fluorescence revealed that many cells entered M phase at once and exhibited prolonged mitosis; eventually progressing to G1 phase not accompanied by cytokinesis; this is an endomitosis-like event. Most of these cells then underwent S/G2 phases at least once, which corroborated the appearance of polyploid cells. However, a small fraction of cells with 2 N DNA content still remained 24 h after the treatment. When co-treated with MAD2 inhibitor, a core factor constituting spindle checkpoint, the 2 N DNA cell fraction disappeared and almost all cells exhibited endomitosis, leading to enhanced sensitivity. Detailed cell cycle analysis revealed that induction of an endomitosis-like event might be associated with CHK1 inhibitor-induced cell death in HeLa cells.

Differential cytokine and metabolite production by cervicovaginal epithelial cells infected with Lactobacillus crispatus and Ureaplasma urealyticum

IntroductionWe sought to quantify targeted metabolites (d-lactate, pyruvate, urea, ammonia) and the cytokine IL-8 produced by human cervicovaginal epithelial cells co-cultured with Ureaplasma urealyticum (a preterm birth-associated bacterium) or Lactobacillus crispatus (a healthy vaginal commensal associated with term birth). MethodsConcentrations of d-lactate, pyruvate, urea and ammonia measured by enzyme-based spectrophotometry and IL-8 by ELISA were determined and compared between monolayer-cultured HeLa cells (ATCC 35241) infected with strains of U. urealyticum (ATCC 27618, 0.5 mL = 3640 CFU/mL, U. urealyticum) or L. crispatus (ATCC 33820, MOI = 10,000, 1000 and 100, L. crispatus) and incubated in 5% CO2 at 37 °C for 24 h. Uninfected HeLa cells (Hc) were used as controls and cytotoxicity was determined by the amount (optical density) of lactate dehydrogenase (LDH) released by the dead HeLa cells. ResultsThe amount of LDH released by untreated Hc (P = 0.002) and U. urealyticum-infected cells (P < 0.0001) was higher than those of L. crispatus-infected cells, with U. urealyticum-infected cells recording the highest % cytotoxicity and L. crispatus-infected cells MOI 10,000 (Lc10,000) the least (P < 0.0001). Though there was no significant difference in the concentration of urea between the samples, U. urealyticum-infected cells showed higher ammonia compared to other samples (p = 0.03). In contrast, all L. crispatus samples had higher d-lactate than untreated Hc (p = 0.01) and U. urealyticum-infected cells (P = 0.01). Also, Lc10,000 had the highest d-lactate (p = 0.001) and lowest pyruvate (P = 0.04, excluding UU) compared to other samples. Furthermore, U. urealyticum-infected cells produced the highest IL-8 (P = 0.01) compared to other samples, with Lc10,000 producing undetectable levels. ConclusionInfection of cervicovaginal epithelial cells by U. urealyticum stimulates production of ammonia from urea and induces elevated IL-8 production possibly leading to significantly higher cytotoxicity. In contrast, L. crispatus appeared protective against HeLa cell inflammation and death, producing more d-lactate and less IL-8, consistent with a role for L. crispatus in promoting vaginal floral health and reducing infection/inflammation-associated preterm birth.

Design, Synthesis, Characterization and Antiproliferative Activities of Ru(II) Complexes of Substituted Benzimidazoles

Synthesis of [Ru(PPh3)2(BZM)2Cl2] (BZM= LS1, LS2, LS3, LS4 and LS5) where LS1=(1H-benzo[d] imidazole-2-yl)methanethiol, LS2 = 2-(4-bromobutyl)-1H-benzo[d] imidazole, LS3= 2-(4-nitrophenyl)-1H-benzo[d]imidazole, LS4 = 2-(4-chlorophenyl)-1H-benzo[d]imidazole and LS5= 4-(1H-benzo[d]imidazol-2-yl)aniline (BZM = benzimidazoles, PPh3 = triphenylphosphine) and metal complexes as MR, [ Ru (PPh3)4Cl2], MLS1, MLS2, MLS3, MLS4 and MLS5 for use as potential anticancer compounds have been investigated. The complexes have been characterized by elemental analysis, IR, multinuclear NMR, UV-visible and ESI-MS spectroscopic techniques. The geometries of all complexes have been optimized by using density functional theory (DFT). The cytotoxicity effects of MR, MLS2 and LS1 were also investigated on Human cervical carcinoma cells (HeLa) by MTT assay, ROS generation and nuclear apoptosis assay. The percent cell viability assessed by MTT assay suggested that the synthesized MR, MLS2 and LS1 significantly reduce the viability of HeLa cells, in a dose-dependent manner. The inhibitory concentration (IC50) of MR, MLS2 and LS1 against HeLa cells was found 90.8, 81.8 and 115 μM, respectively. These compounds also induced the over production of intracellular reactive oxygen species (ROS) as well as the condensed and fragmented nucleus, which supports the molecular mechanism of cell death by apoptosis. The investigations suggested that the compounds MR, MLS2 and LS1 induce the cell death in HeLa cells through apoptotic pathway.

Pereskia bleo Leaves Extract Induces Cell Death via Cell Cycle Arrest and Apoptosis in Cervical Cancer Cells HeLa

Introduction: Pereskia bleo is a leafy and edible plant, locally known as “Pokok Jarum Tujuh Bilah” which has anticancer properties. This study purposed to determine the cytotoxic effects of P. bleo leaves extracts on several well-known cancer cells and elucidate its underlying mechanism in inducing cell death.Methods: Cytotoxic activity on selected cell lines was determined using MTT assay. Mechanism of cell death was investigated through cell cycle and Annexin V assay. Expression of apoptotic proteins was measured by flow cytometry method.Results: Ethyl acetate extract of P. bleo leaves (PBEA) appeared to have the strongest IC50 value (14.37 ± 8.40 μg/ml) and most active against HeLa cells was further studied for apoptosis. The cell cycle investigation by flow cytometry evidenced the increment of PBEA treated HeLa cells in G0/G1 phase and apoptotic event was detected in Annexin V assay. Analysis of apoptotic protein showed pro-apoptotic proteins (Bax, p53 and caspase 3) were triggered where as anti-apoptotic protein Bcl-2 was suppressed in treated HeLa cells.Conclusions: Our findings demonstrated that PBEA treatment induced cell death in HeLa cells by p53-mediated mechanism through arresting cell cycle at G0/G1 phase and mitochondrial-mediated pathway with involvement of pro-apoptotic proteins, anti-apoptotic protein, and caspase 3.

Functional Validation of DownRegulated MicroRNAs in HeLa Cells Treated with Polyalthia longifolia Leaf Extract Using Different Microscopic Approaches: A Morphological Alteration-Based Validation.

Several microscopy methods have been developed to assess the morphological changes in cells in the investigations of the mode of cell death in response to a stimulus. Our recent finding on the treatment of the IC50 concentration (26.67 μg/mL) of Polyalthia longifolia leaf extract indicated the induction of apoptotic cell death via the regulation of miRNA in HeLa cells. Hence, the current study was conducted to validate the function of these downregulated microRNAs in P. longifolia-treated HeLa cells using microscopic approaches. These include scanning electron microscope (SEM), transmission electron microscope (TEM), and acridine orange/propidium iodide (AO/PI)-based fluorescent microscopy techniques by observing the morphological alterations to cells after transfection with mimic miRNA. Interestingly, the morphological changes observed in this study demonstrated the apoptotic hallmarks, for instance, cell blebbing, cell shrinkage, cytoplasmic and nuclear condensation, vacuolization, cytoplasmic extrusion, and the formation of apoptotic bodies, which proved the role of dysregulated miRNAs in apoptotic HeLa cell death after treatment with the P. longifolia leaf extract. Conclusively, the current study proved the crucial role of downregulated miR-484 and miR-221-5p in the induction of apoptotic cell death in P. longifolia-treated HeLa cells using three approaches-SEM, TEM, and AO/PI-based fluorescent microscope.

Precisely Control Mitochondria with Light to Manipulate Cell Fate Decision

Mitochondrial dysfunction has been implicated in many pathological conditions and diseases. The normal functioning of mitochondria relies on maintaining the inner mitochondrial membrane potential (also known as ΔΨm) that is essential for ATP synthesis, Ca2+ homeostasis, redox balance, and regulation of other key signaling pathways such as mitophagy and apoptosis. However, the detailed mechanisms by which ΔΨm regulates cellular function remain incompletely understood, partially because of the difficulty of manipulating ΔΨm with spatiotemporal resolution, reversibility, or cell type specificity. To address this need, we have developed a next generation optogenetic-based technique for controllable mitochondrial depolarization with light. We demonstrate successful targeting of the heterologous channelrhodopsin-2 fusion protein to the inner mitochondrial membrane and formation of functional cationic channels capable of light-induced selective ΔΨm depolarization and mitochondrial autophagy. Importantly, we for the first time, to our knowledge, show that optogenetic-mediated mitochondrial depolarization can be well controlled to differentially influence the fate of cells expressing mitochondrial channelrhodopsin-2; whereas sustained moderate light illumination induces substantial apoptotic cell death, transient mild light illumination elicits cytoprotection via mitochondrial preconditioning. Finally, we show that Parkin overexpression exacerbates, instead of ameliorating, mitochondrial depolarization-mediated cell death in HeLa cells. In summary, we provide evidence that the described mitochondrial-targeted optogenetics may have a broad application for studying the role of mitochondria in regulating cell function and fate decision.

In vitro anti-proliferative and anti-bacterial properties of new C7 benzoate derivatives of pinocembrin

In the present work, the in vitro anti-proliferative and anti-bacterial activities of three semi-synthetic benzoate pinocembrin derivatives, isolated from the aerial parts of Glycyrrhiza glabra L., were investigated. As occurs in most natural compounds, the bioavailability of pinocembrin is very poor, therefore it should be improved by chemical strategies aimed to prolong its shelf life and, consequently, its activity. On this basis, three benzoate derivatives of pinocembrin (a1–a3) were synthesised and assayed in order to ascertain their biological value. Among them, compound a1 showed the highest anti-proliferative activity on a wide panel of cancer cell lines, as well as low toxic effects on non-malignant breast cells. The calculated IC50 values in HeLa and SKBR3 cells were 8.5 and 12.7 µM, respectively. Briefly, a1 treatment increased ROS levels, induced mitochondrial membrane damage leading to necrotic death of HeLa cells. Moreover, a1 displayed a promising anti-bacterial activity.

In vitro induction of endoplasmic reticulum stress in human cervical adenocarcinoma HeLa cells by fucoidan

Fucoidan is a sulfated hetero-polysaccharide, found in cell-wall composition of brown algae. Recent studies have reported the role of fucoidan in the induction of Endoplasmic Reticulum (ER) stress-related cell death in cancer cells but the mechanism of action of fucoidan in cervical HeLa cells is not well-known. The purpose of this study was to investigate if fucoidan induces HeLa cells death through ER-stress-related cell death and G1 phase arrest. 200–600 μg/ml concentrations of fucoidan inhibited the proliferation of HeLa cells after 48 h of treatment while investigated normal cell lines (HaCaT: Keratinocytes and HEK-293: embryonic kidney) were not affected. The exposure of HeLa cells to these concentrations of fucoidan induced phosphorylation of ER stress sensors followed by upregulation of Bip/GRP78, CHOP expression which triggered a buildup of malfolded proteins in ER, therefore, initiating unfolded protein response (UPR) mechanism. In addition, intracellular calcium levels were elevated following the treatment suggesting that this contributed to the ER stress-induced apoptosis. Fucoidan treatment caused G1phase arrest by inducting CDKIs and inhibiting CDKs and Cyclins as well as apoptosis by activating the mitochondrial-dependent pathway in HeLa cells. We demonstrated that Fucoidan inhibits HeLa cells proliferation by inducing apoptosis, G1 phase arrest, ER stress, and mitochondrial-mediated apoptosis.

Synthesis, Crystal Structures, and Anti‐cervical Cancer Activity Evaluation of Three Trinuclear Transition Metal(II) Complexes with N,O‐Donor Schiff Base Ligand

A new bi‐nucleating Schiff base ligand, 2‐(((3‐(dimethylamino)propyl)imino)methyl)‐6‐methoxyphenol (HL1) was prepared by a one‐pot condensation reaction, which was further used in the construction of three trinuclear Schiff base transition metal(II) complexes [Cu3(L1)2(OH)2(H2O)2](NO3)2 (1), [Co3(L1)2(OH)2(H2O)2](NO3)2 (2), and [Cu3(L1)2(N3)4] (3). Furthermore, a green hand grinding technique was implemented to reduce the particle size of the coordination complexes to generate the nanoscale compounds. The SEM studies reveal the formation of square and spherical particles for nano 1 and 2, and nanorod for nano 3. In addition, the anti‐proliferation activity of nano 1–3 was detected on the human cervical cancer Hela cells with CCK‐8 assay. The cell viability curves and IC50 values indicated that only nano 1 has anti‐proliferation activity on Hela cells. To further investigate the mechanism of nano 1 induced Hela cell death, the Annexin V‐FITC/PI double staining assay, western blot assay, and ROS level detection was conducted.