Acid In HeLa Cells Research Articles

A fluorescein-based “turn-on” fluorescence probe for hypochlorous acid detection and its application in cell imaging

A simple fluorescent probe F-BH was designed and synthesized, introducing CN group which can be a recognition site for hypochlorous acid into the fluorescent probe molecule by using 2-benzothiazole hydrazone and formylated fluorescein. The fluorescence intensity of the probe F-BH solution was very weak, while the fluorescence of the solution was obviously enhanced and the color of the solution changed after the addition of ClO− ion. The selection and competition experiments proved that the probe has great selectivity for recognition of hypochlorous acid over other ROSs/RNSs and anions. Fluorescence titration experiments show that the probe has a low detection limit (17.5 nM). The probe has been successfully applied to real-time detection of hypochlorous acid in Hela cells.

Protolichesterinic acid enhances doxorubicin-induced apoptosis in HeLa cells in vitro

AimThe aim of this study was to investigate the effect of protolichesterinic acid, a lichen secondary metabolite, on anti-proliferative activity of doxorubicin in three human cancer cell lines, HeLa, SH-SY5Y and K562 cells. Main methodsThe data obtained from MTT assays, performed on cells treated with protolichesterinic acid and doxorubicin alone and in combination, were analysed by the median-effect method as proposed by Chou and Talalay and the Bliss independence model. Apoptosis rate was evaluated by fluorescence microscopy, caspase-3, 8 and 9 activities were detected by spectrofluorimetric analysis and protein expression of Bim, Bid, Bax and Mcl-2 was analysed by Western blotting. The interaction of protolichesterinic acid with thioesterase domain of human fatty acid synthase (hFAS) was investigated by a molecular docking study. Key findingsThe in vitro activity of doxorubicin against HeLa cancer cell line, but not against SH-SY5Y and K562 cells, was synergically increased by protolichesterinic acid. The increased cytotoxicity caused by protolichesterinic acid in HeLa cells was due to a pro-apoptotic effect and was associated to caspase-3, 8 and 9 activation. The simultaneous treatment for 24h with protolichesterinic acid plus doxorubicin caused an increase of Bim protein expression and the appearance of cleaved form of Bid protein. The molecular modelling analysis showed that protolichesterinic acid seemed to behave as a competitive inhibitor of hFAS. SignificanceThese results suggest that protolichesterinic acid could be envisaged as an useful tool against certain types of tumor cells in combination with anticancer drugs.

Histone deacetylase (HDAC) inhibitory and antiproliferative activities of phenolic-rich extracts derived from the rhizome of Hydnophytum formicarum Jack.: sinapinic acid acts as HDAC inhibitor

BackgroundThe rhizome of Hydnophytum formicarum Jack., a medicinal plant known in Thai as Hua-Roi-Roo, has been used in Thai traditional herbal medicine for treatment of cancer. We assessed the ability of its ethanolic and phenolic-rich extracts and its major phenolic compound, sinapinic acid, possessing histone deacetylase (HDAC) inhibitory activity to inhibit proliferation of 5 human cancer cell lines.MethodsHeLa cells were used to study HDAC inhibitory activity of the extracts, sinapinic acid, and a well-known HDAC inhibitor sodium butyrate. Five human cancer cell lines and one non-cancer cell line were used to study antiproliferative activities of the plant extracts, sinapinic acid and sodium butyrate, comparatively.ResultsResults indicated that ethanolic and phenolic-rich extracts of H. formicarum Jack. rhizome possessed both antiproliferative activity and HDAC inhibitory activity in HeLa cells. Sinapinic acid, despite its lower HDAC inhibitory activity than the well-known HDAC inhibitor sodium butyrate, inhibited the growth of HeLa and HT29 cells more effectively than sodium butyrate. However, sinapinic acid inhibited the growth of HCT116 and Jurkat cells less effectively than sodium butyrate. The non-cancer cell line (Vero cells) and breast cancer cell line (MCF-7 cells) appeared to be resistant to both sinapinic acid and sodium butyrate. The growth inhibitory effects of the ethanolic and phenolic-rich extracts and sinapinic acid in HeLa cells were mediated by induction of apoptosis.ConclusionsThe results of this study support the efficacy of H. formicarum Jack. rhizome ethanolic and phenolic-rich extracts for the treatment of cervical cancer, colon cancer, and T- cell leukemia in an alternative medicine. Further studies of other active ingredients from this plant are needed.

Cytotoxic Activity and Antioxidant Capacity of Purified Lichen Metabolites: An In Vitro Study

The purpose of this study was to investigate the effects of six lichen metabolites (diffractaic acid, lobaric acid, usnic acid, vicanicin, variolaric acid, protolichesterinic acid) on proliferation, viability and reactive oxygen species (ROS) level towards three human cancer cell lines, MCF-7 (breast adenocarcinoma), HeLa (cervix adenocarcinoma) and HCT-116 (colon carcinoma). Cells were treated with different concentrations (2.5-100 μM) of these compounds for 48 h. In this comparative study, our lichen metabolites showed various cytotoxic effects in a concentration-dependent manner, and usnic acid was the most potent cytotoxic agent, while variolaric acid did not inhibit the proliferation of any of the three cell lines used. All tested lichen compounds did not exhibit free radical scavenging activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The lichen metabolites did not significantly increase the intracellular ROS level and did not prevent oxidative injury induced by t-butylhydroperoxide in HeLa cells. To better clarify the mechanism(s) of cytotoxic effect induced by protolichesterinic acid in HeLa cells, we investigated apoptotic markers such as condensation and fragmentation of nuclear chromatin and activation of caspase-3, 8 and 9. Our results revealed that the antiproliferative activity of 40 μM protolichesterinic acid in HeLa cells is related to its ability to induce programmed cell death involving caspase-3, 8 and 9 activation.

Folate-PEG modified poly(2-(2-aminoethoxy)ethoxy)phosphazene/DNA nanoparticles for gene delivery: Synthesis, preparation and in vitro transfection efficiency

Target-specific technique can significantly enhance the efficacy of gene delivery system which was limited by many cellular barriers. In this work, a new folate-PEG modified poly(2-(2-aminoethoxy)ethoxy)phosphazene (PAEP), namely, folate-PEG-PAEP was synthesized as a folate receptor (FR) targeted carrier, and the cytotoxicity, transfection efficiency, cellular uptake and intracellular trafficking of folate-PEG-PAEP/DNA nanoparticles (FPPN) were investigated. Compared with the PAEP/DNA nanoparticles (PN), the cytotoxicity of FPPN decreased significantly at high dose. FPPN showed much higher transfection efficiency (15.85 ± 1.23%) compared with PN (6.71 ± 0.42%) in FR overexpressing Hela cells, but no significant difference was observed in CHO-k1 cells lacking FR. The transfection activity of FPPN could be reversed in the presence of 1.0 mM free folic acid in Hela cells. The cellular uptake of FPPN was 37.38% higher than that of PN in Hela cells. These results indicated that FPPN could be a potential targeted gene delivery system.

Differential effects of class I isoform histone deacetylase depletion and enzymatic inhibition by belinostat or valproic acid in HeLa cells

BackgroundHistone acetylation is an epigenetic modification involved in the regulation of gene expression, balanced by histone acetyl transferases and histone deacetylase (HDAC) enzymes. HDAC inhibitors (HDACi) induce growth arrest and cell death in transformed cells, and are currently in many clinical cancer trials. The transcriptional response to HDACi is complex, as is the response to HDAC isoform knockdown (KD). Here, we describe for the first time in a human cancer cell line, a transcriptional comparison of treatment by two structurally unrelated HDACi; belinostat and valproic acid with the KD of HDAC1, 2 and 3 isoforms.ResultsHDAC KD showed anti-proliferative effects, although to a lesser extent than HDACi treatment. Moreover, we found a 2-fold increased resistance of HDAC1 knockdown cells to belinostat, suggesting this isoenzyme as a selective target. While both HDACi treatment and individual class I HDAC KD produce significant transcriptional effects, three-times higher for HDACi, the gene-expression profiles of class I HDAC KD compared with that obtained by HDACi treatment exhibited less than 4% of altered genes in common between the two modes of inhibition. Further, cell-specific effects of HDAC KD are evident by comparison with a recent study in a different cell line.ConclusionThe increased resistance to belinostat in response to HDAC1 depletion indicates the possibility of using this isoform as a predictive biomarker of response to HDACi treatment. Further, the transcriptional response to chemical inhibition of HDACs is very different from that of KD of individual class I HDAC isoforms. These data suggest that the anti-tumor effect of HDACi is indeed linked to class I inhibition, but may be more complex than simply targeting individual HDAC enzymes.

The role of monocarboxylate transporters in uptake of lactic acid in HeLa cells

This study was aimed to identify the monocarboxylate transporters (MCTs) in HeLa cells and to delineate their role in transportation of l-lactic acid. The functional role of MCTs in lactic acid transport was evaluated at various mucosal pHs (4.5–7.4) or in the presence of various loading doses (0.2–2 mM) of lactic acid, MCT substrates (nicotinic acid, n-butyric acid, etc.) and inhibitors (α-cyano-4-hydroxycinnamate and para-chloromercuribenzoic acid). The molecular properties of MCTs were characterized using reverse transcription-polymerase chain reaction (RT-PCR). The uptake rate of lactic acid by HeLa cells significantly increased from 0.353 ± 0.052 to 1.103 ± 0.196 μmol/mg protein as the extra-cellular pH changed from 7.4 to 4.5, indicating that activities of MCT were mediated through H +-linked mechanism. The uptake profile of lactic acid followed the saturable process with the K m value of 0.53 mM. The uptake rate of lactic acid is concentration dependent and is reduced in the presence of MCT inhibitors. MCT isoforms 1, 5 and 6 in HeLa cells were identified by RT-PCR. HeLa cell line can be used as an effective screening tool for intravaginally administered drugs targeted toward MCT.

Antiproliferative and Antiviral Mechanism of Ursolic Acid in Cervical Carcinoma Cell Lines

Objective : Ursolic acid which has been used as a herb medication, was reported for anti-cancer and anti-inflammatory effects. We tried to analyze the anti-proliferative and anti-viral effects of ursolic acid in Human papillomavirus (HPV) associated cervical carcinoma cell lines. Methods : We treated ursolic acid or dexamethasone to cervical carcinoma cell lines. We carried out MTT assay to observe the anti-proliferative effects and tried to find out the characteristics of apoptosis by DNA fragmentation, DAPI staining and FACS analysis. By means of western blotting, we investigated proteins related with apoptosis. After treating of ursolic acid, we used RT-PCR for the expression of HPV E6 and E7 gene to observe the anti-viral effects. Through proteomics analysis including two-dimensional electrophorosis (2DE) and matrix-associated laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), we found the interaction between cell cycle regulatory factor and apoptosis related protein, and also demonstrated anti-cancer and anti-viral mechanism. Results : While the growth of HPV-positive cervical carcinoma cell lines (HeLa, CaSki, SiHa) is suppressed by ursolic acid in a dose- and time-dependent manner, that of HPV-negative cervical carcinoma cell line (C33A) did not have any inhibitory effects on proliferation. As we increased the concentrations of ursolic acid in HeLa cell, the typical characteristics of apoptosis were noted in DNA fragmentation, DAPI staining and FACS analysis, The expression of Fas protein was induced and caspase-8, caspase-3 and PARP proteins changed into cleavaged forms after treating ursolic acid. HPV-18 E6/E7 gene expression decreased after treating ursolic acid in HeLa cells, but the levels of p53 and Rb proteins did not changed. Total 30 spots were detected by proteomics analysis, along with 20 up-regulated, 6 down-regulated and 4 unknown protein were founded. Conclusion : These results suggest that ursolic acid inhibit the cell proliferation through apoptosis in HPV-associated cervical carcinoma cell lines. The apoptotic mechanism of ursolic acid in HeLa cells might be through the signal pathway “Fas→caspase-8→PARP”. In addition, the antiviral effect of ursolic acid through suppression of HPV E6/E7 gene expression would contribute to growth inhibition in HeLa cells. These results suggest that ursolic acid could be useful for an effective anticancer drug in treatment of HPV-associated cervical neoplasia.

The Mechanism of Apoptosis by the Oleic Acid in HeLa Cells : Caspase-independent Pathway by Induction of IκBβ

The Mechanism of Apoptosis by the Oleic Acid in HeLa Cells : Caspase-independent Pathway by Induction of IκBβ

Cdc2-Independent Induction of Premature Mitosis by Okadaic Acid in HeLa Cells

The induction of premature mitosis by okadaic acid (OA) in HeLa cells in S-phase or in G 2-phase has been studied using light microscopy, immunofluorescence, and immunochemical techniques. The observations indicate an involvement of a cdc2-independent pathway in these cells. It has been claimed that inhibition of an OA-sensitive phosphatase, possibly of PP1, induces activation of a kinase which is sensitive to staurosporine and Zn 2+. This kinase brings about mitosis-specific cytoskeletal rearrangements, chromosome condensation, and nuclear envelope breakdown, inducing a mitosis-like state. However, other mitotic events do not follow. The possibility that this kinase may be a NIMA-like Nek2 kinase is discussed.

Selective induction of cell cycle regulatory genes cdk1 (p34cdc2), cyclins A/B, and the tumor suppressor gene Rb in transformed cells by okadaic acid.

Genes encoding cdk1 (p34cdc2), cyclin A, cyclin B, and the tumor suppressor gene Rb are fundamental regulators of cell cycle progression which associate as a complex with the transcription factor E2F. Expression of many of these proteins has previously been shown to be repressed by okadaic acid, a specific inhibitor of protein phosphatases 1/2A (PP1/PP2A), resulting in growth arrest in nontransformed but immortalized cells. We have investigated levels of mRNA encoding cdk1 (p34cdc2), cyclin A, cyclin B, Rb, GAPDH, c-myc, and histone H4 genes for sensitivity to okadaic acid in HeLa cells to determine if transformation altered their regulation. Serum starvation slowed growth and diminished mRNA levels for all genes tested except c-myc and GAPDH. When starved cells were subsequently exposed to 19 nM okadaic acid or refed 10% serum, mRNA levels of cyclin A, cyclin B, cdk1, and Rb dramatically increased while mRNA levels for c-myc and GAPDH were largely unaffected. Histone H4 mRNA levels and the rate of DNA synthesis were greatly enhanced by serum addition but not affected appreciably by okadaic acid. Okadaic acid was also effective in blocking proliferation of exponentially growing HeLa cells at G2/M and S phase. Despite the cell cycle phase-specific block, elevated mRNA levels for cdk1, cyclin A, cyclin B, Rb, and suppression of H4 mRNA levels were detected and persisted for at least 12 hr following okadaic acid removal. The results demonstrate that cell cycle progression is blocked and several cell cycle regulatory genes, encoding transcription factor E2F-associated proteins, experience elevation of mRNA levels through mechanisms sensitive to okadaic acid likely through a PP1/PP2A-sensitive mechanism. Data from transformed cells contrast with data from immortalized but nontransformed cells in which okadaic acid also blocks cell cycle progression during G2/M phase but suppresses expression of these genes. Such contrasts may be correlated with reduced growth factor dependence and transformation.

Synthesis and turnover of mitochondrial ribonucleic acid in HeLa cells: the mature ribosomal and messenger ribonucleic acid species are metabolically unstable.

The synthesis rates and half-lives of the individual mitochondrial ribosomal ribonucleic acid (RNA) and polyadenylic acid-containing RNA species in HeLa cells have been determined by analyzing their kinetics of labeling with [5-3H]-uridine and the changes in specific activity of the mitochondrial nucleotide precursor pools. In one experiment, a novel method for determining the nucleotide precursor pool specific activities, using nascent RNA chains, has been utilized. All mitochondrial RNA species analyzed were found to be metabolically unstable, with half-lives of 2.5 to 3.5 h for the two ribosomal RNA components and between 25 and 90 min for the various putative messenger RNAs. A cordycepin "chase" experiment yielded half-life values for the messenger RNA species which were, in general, larger by a factor of 1.5 to 2.5 than those estimated in the labeling kinetics experiments. On the basis of previous observations, a model is proposed whereby the rate of mitochondrial RNA decay is under feedback control by some mechanism linked to RNA synthesis or processing. A short half-life was determined for five large polyadenylated RNAs, which are probably precursors of mature species. A rate of synthesis of one to two molecules per minute per cell was estimated for the various H-strand-coded messenger RNA species, and a rate of synthesis 50 to 100 times higher was estimated for the ribosomal RNA species. These data indicate that the major portion of the H-strand in each mitochondrial deoxyribonucleic acid molecule is transcribed very infrequently, possibly as rarely as once or twice per cell generation. Furthermore, these results are consistent with a previously proposed model of H-strand transcription in the form of a single polycistronic molecule.

Synthesis and turnover of mitochondrial ribonucleic acid in HeLa cells: the mature ribosomal and messenger ribonucleic acid species are metabolically unstable.

The synthesis rates and half-lives of the individual mitochondrial ribosomal ribonucleic acid (RNA) and polyadenylic acid-containing RNA species in HeLa cells have been determined by analyzing their kinetics of labeling with [5-3H]-uridine and the changes in specific activity of the mitochondrial nucleotide precursor pools. In one experiment, a novel method for determining the nucleotide precursor pool specific activities, using nascent RNA chains, has been utilized. All mitochondrial RNA species analyzed were found to be metabolically unstable, with half-lives of 2.5 to 3.5 h for the two ribosomal RNA components and between 25 and 90 min for the various putative messenger RNAs. A cordycepin "chase" experiment yielded half-life values for the messenger RNA species which were, in general, larger by a factor of 1.5 to 2.5 than those estimated in the labeling kinetics experiments. On the basis of previous observations, a model is proposed whereby the rate of mitochondrial RNA decay is under feedback control by some mechanism linked to RNA synthesis or processing. A short half-life was determined for five large polyadenylated RNAs, which are probably precursors of mature species. A rate of synthesis of one to two molecules per minute per cell was estimated for the various H-strand-coded messenger RNA species, and a rate of synthesis 50 to 100 times higher was estimated for the ribosomal RNA species. These data indicate that the major portion of the H-strand in each mitochondrial deoxyribonucleic acid molecule is transcribed very infrequently, possibly as rarely as once or twice per cell generation. Furthermore, these results are consistent with a previously proposed model of H-strand transcription in the form of a single polycistronic molecule.

Ascorbic acid and dehydroascorbic acid in HeLa cells: their effect on the collagen-peptidase activity of glucose-deficient cultures

HeLa cells in culture do not accumulate ascorbic acid unless ascorbic acid or dehydroascorbic acid is available in the medium. Collagen peptidase corresponding to the activity found in the invasive zone of tumours, and acid phosphatase, in HeLa cells cultured under normal conditions, are unaffected by ascorbic acid, but are reduced in cells deprived of carbohydrate. These reduced collagen-peptidase levels, but not acid phosphatase, are restored to the values of normal HeLa cells by ascorbic acid. The relevance of these findings is considered in the context of tumour growth and spread.

The serum dependence of the occurrence of N-glycolylneuraminic acid in HeLa cells

The occurrence of N-glycolylneuraminic acid in HeLa cells is shown to be due to the calf serum added to the growth medium, and not to their cancerous nature. When Hela cells are grown with human serum as supplement, only N-acetylneuraminic acid can be found. The ganglioside composition of these cells is also reported.

Effect of Neuraminidase on the Accumulation of Alpha-Aminoisobutyric Acid in HeLa Cells

SummaryAn amino acid transport system in HeLa cells utilizing 14C-l-alpha-aminoisobutyric acid is described. Neuraminidase treatment of HeLa cells decreases the net accumulation of amino acid without alteration of the rate of efflux of preloaded cells. These studies suggest that the sialic acid residue of the external cell surface may have a significant role in amino-acid transport in human cells.

Effect of hydrocortisone on HeLa cells with special reference to the RNA metabolism.

Hydrocortisone (HC) inhibited the growth of HeLa cells at the concentration of 0.01-10μg/ml but enhanced it at 0.001μg/ml.HC increased the β-glucuronidase and alkaline phosphatase activities of HeLa cells at 10μg/ml in 4 days, although it did not affect the acid phosphatase activity.Nucleic acids obtained from growing HeLa cells were fractionated by methylated bovine serum albumin column chromatography. Two peaks of rapidly labeled RNA were found in the chromatogram, and from the experiment of time course of 32P-labeling and base composition analysis, it was assumed that one was the precursor of r-RNA and the other d RNA possibly containing m-RNA.HC (10μg/ml) inhibited the synthesis of nucleic acid in HeLa cells; in early period of HC treatment, only the d-RNA synthesis was slightly inhibited, while with longer treatment the synthesis of r-RNA precursor was most strongly inhibited in contrast with the weak inhibition of DNA and d-RNA syntheses.From these data, the relationship between the catabolic action and enzyme-inducing action of HC was discussed.

On the presence of N-glycolyneuraminic acid in HeLa cells

On the presence of N-glycolyneuraminic acid in HeLa cells

Secondary methylation of ribosomal ribonucleic acid in HeLa cells

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSecondary methylation of ribosomal ribonucleic acid in HeLa cellsErnest F. ZimmermanCite this: Biochemistry 1968, 7, 9, 3156–3164Publication Date (Print):September 1, 1968Publication History Published online1 May 2002Published inissue 1 September 1968https://doi.org/10.1021/bi00849a019RIGHTS & PERMISSIONSArticle Views20Altmetric-Citations29LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (940 KB) Get e-Alerts Get e-Alerts

Sialic acid in HeLa cells: effect of hydrocortisone.

HeLa S(3) cells grown in the presence of hydrocortisone contain more sialic acid than their corresponding untreated controls. The percentage of the total sialic acid present in the sedimentable fraction obtained from homogenates of cells treated with hydrocortisone is smaller than that of the corresponding fraction of control cells. In addition to N-acetylneuraminic acid, the chromatographic analysis suggests that HeLa S(3) cells probably contain trace amounts of N-glycolylneuraminic acid.