Colon HCT-116 Cancer Cells Research Articles

Effect of Acacia concinna Extract on Apoptosis Induction Associated with Endoplasmic Reticulum Stress and Modulated Intracellular Signaling Pathway in Human Colon HCT116 Cancer Cells

Effect of Acacia concinna Extract on Apoptosis Induction Associated with Endoplasmic Reticulum Stress and Modulated Intracellular Signaling Pathway in Human Colon HCT116 Cancer Cells

Distribution and Level of Bioactive Monoacylglycerols in 12 Marine Microalgal Species.

Microalgae are currently considered an attractive source of highly valuable metabolites potentially exploitable as anticancer agents, nutraceuticals and cosmeceuticals and for bioenergy purposes. Their ease of culturing and their high growth rates further promote their use as raw material for the production of specialty products. In the present paper, we focused our attention on specific glycerol-based lipid compounds, monoacylglycerols (MAGs), which displayed in our previous studies a selective cytotoxic activity against the haematological U-937 and the colon HCT-116 cancer cell lines. Here, we performed a quali/quantitative analysis of MAGs and total fatty acids (FAs) along with a profiling of the main lipid classes in a panel of 12 microalgal species, including diatoms and dinoflagellates. Our results highlight an inter- and intraspecific variability of MAG profile in the selected strains. Among them, Skeletonema marinoi (strain FE7) has emerged as the most promising source for possible biotechnological production of MAGs.

A comparative study of boron-containing and boron-omitted capsaicinoids

This study reports the synthesis and characterization of a limited number of novel boron-containing and boron-omitted capsaicinoids, providing 12 unique substrates. We have previously reported boron-containing capsaicinoids that showed improved bioactivity compared to capsaicin itself but have yet to test a series of analogous boron-omitted substrates as a direct comparison. The boron-containing capsaicinoids bear a pinacolboronate ester (Bpin) group, which was incorporated using an iridium-catalyzed hydroboration reaction. We report that although nearly all compounds display moderate cytotoxic activity that bests that of capsaicin against human colon HCT116 cancer cells, the activity of our boron-omitted capsaicinoids surpasses that of the boron-containing analogues.

Counteracting Colon Cancer by Inhibiting Mitochondrial Respiration and Glycolysis with a Selective PKCδ Activator.

Metabolic reprogramming is a central hub in tumor development and progression. Therefore, several efforts have been developed to find improved therapeutic approaches targeting cancer cell metabolism. Recently, we identified the 7α-acetoxy-6β-benzoyloxy-12-O-benzoylroyleanone (Roy-Bz) as a PKCδ-selective activator with potent anti-proliferative activity in colon cancer by stimulating a PKCδ-dependent mitochondrial apoptotic pathway. Herein, we investigated whether the antitumor activity of Roy-Bz, in colon cancer, could be related to glucose metabolism interference. The results showed that Roy-Bz decreased the mitochondrial respiration in human colon HCT116 cancer cells, by reducing electron transfer chain complexes I/III. Consistently, this effect was associated with downregulation of the mitochondrial markers cytochrome c oxidase subunit 4 (COX4), voltage-dependent anion channel (VDAC) and mitochondrial import receptor subunit TOM20 homolog (TOM20), and upregulation of synthesis of cytochrome c oxidase 2 (SCO2). Roy-Bz also dropped glycolysis, decreasing the expression of critical glycolytic markers directly implicated in glucose metabolism such as glucose transporter 1 (GLUT1), hexokinase 2 (HK2) and monocarboxylate transporter 4 (MCT4), and increasing TP53-induced glycolysis and apoptosis regulator (TIGAR) protein levels. These results were further corroborated in tumor xenografts of colon cancer. Altogether, using a PKCδ-selective activator, this work evidenced a potential dual role of PKCδ in tumor cell metabolism, resulting from the inhibition of both mitochondrial respiration and glycolysis. Additionally, it reinforces the antitumor therapeutic potential of Roy-Bz in colon cancer by targeting glucose metabolism.

In Vitro Antitumor Evaluation of Acrylic Acid Derivatives Bearing Quinolinone Moiety as Novel Anticancer Agents.

Due to the emergence of resistance to available anticancer agents, the demand for new cytotoxic agents has grown. This study aims at synthesis and cytotoxic evaluation of new acrylic acid derivatives bearing quinolinone and halogenated quinolinone derivatives against three cancer cell lines. New acrylic acid derivatives bearing quinolinone and halogenated quinolinone moieties were synthesized and screened for their cytotoxic activity against breast MCF-7, liver HepG2, and colon HCT-116 cancer cell lines. Molecules 3 and 8 showed the most potent cytotoxic activity against HCT-116. DNA flow cytometry assay showed cell cycle arrest at the G1 phase and cellular apoptosis. Moreover, molecules 3 and 8 showed cyclin-dependent kinase 2 (CDK2) inhibitory activity compared to the untreated control sample. Acrylic acid derivatives bearing quinolinone and halogenated quinolinone moieties represent an important core and could be used as a lead for further development of drug compounds in order to achieve promising therapeutic results.

Hydrazonoyl chlorides possess promising antitumor properties

Aimsthe main purpose of this study was to identify new selective antitumor agents. Main methodsseveral hydrazonoyl chlorides (HCs) were synthesized and human tumor cell line viability was determined using the MTT assay. Tumor development was assessed using Ehrlich ascites carcinoma (EAC)-bearing mice. Key findingsour results showed that 2-oxo-N-phenyl-2-(phenylamino)acetohydrazonoyl chloride (compound 4; CPD 4) and 2-oxo-2-(phenylamino)-N-(p-tolyl)acetohydrazonoyl chloride (CPD 5) were the most cytotoxic HCs to human cervical tumor HeLa (IC50: 20 and 25 μM for CPD 4 and 5 respectively), breast MCF7 (IC50: 29 and 34 μM for CPD 4 and 5 respectively) and colon HCT116 cancer cells (IC50: 26 and 25 μM for CPD 4 and 5 respectively) with the least cytotoxicity to human non-tumor CCD-18Co colon fibroblasts as well as murine splenocytes. The active compounds significantly inhibited colony formation as well as tumor development in EAC-bearing mice. We also observed that PTEN-deficient cells displayed greater sensitivity than cells expressing wild type PTEN. At the molecular level, comet and cell cycle analyses indicated that the active compounds generate DNA damage. In light of the PTEN-dependent sensitivity and genomic instability we examined the influence of HCs on the DNA repair enzyme polynucleotide kinase/phosphatase (PNKP) and the PI3K/AKT/mTOR pathway, which are each known to be synthetic lethal with PTEN. We found that both PNKP and the PI3K/AKT/mTOR pathway to be adversely affected by the HCs, which may partially account for their toxicity. Significancehydrazonoyl chlorides can be considered as hit compounds for the development of new antitumor agents.

Synthesis and biological activity of novel zingerone-thiohydantoin hybrids

A series of zingerone?thiohydantoin hybrids were synthesized from O-alkyl zingerone derivatives by cyclocondensation with thiosemicarbazide in a two-step reaction. The obtained new potentially bioactive compounds were structurally characterized by IR and NMR spectroscopy, as well as by elemental and HRMS analysis. In addition, their antimicrobial and in vitro anticancer activities were tested. The tested compounds showed low to moderate antimicrobial activity. Zingerone?thiohydantoin hybrid with an O-butyl substituent exerted the significant cytotoxic activity on colon HCT-116 cancer cells, without toxicity on healthy MRC-5 cells.

Synthesis, Characterization, In Vitro Anticancer Potentiality, and Antimicrobial Activities of Novel Peptide-Glycyrrhetinic-Acid-Based Derivatives.

Glycyrrhetinic acid (GA) is one of many interesting pentacyclic triterpenoids showing significant anticancer activity by triggering apoptosis in tumor cell lines. This study deals with the design and synthesis of new glycyrrhetinic acid (GA)–amino acid peptides and peptide ester derivatives. The structures of the new derivatives were established through various spectral and microanalytical data. The novel compounds were screened for their in vitro cytotoxic activity. The evaluation results showed that the new peptides produced promising cytotoxic activity against the human breast MCF-7 cancer cell line while comparing to doxorubicin. On the other hand, only compounds 3, 5, and 7 produced potent activity against human colon HCT-116 cancer cell line. The human liver cancer (HepG-2) cell line represented a higher sensitivity to peptide 7 (IC50; 3.30 μg/mL), while it appeared insensitive to the rest of the tested peptides. Furthermore, compounds 1, 3, and 5 exhibited a promising safety profile against human normal skin fibroblasts cell line BJ-1. In order to investigate the mode of action, compound 5 was selected as a representative example to study its in vitro effect against the apoptotic parameters and Bax/BCL-2/p53/caspase-7/caspase-3/tubulin, and DNA fragmentation to investigate beta (TUBb). Additionally, all the new analogues were subjected to antimicrobial assay against a panel of Gram-positive and Gram-negative bacteria and the yeast candida Albicans. All the tested GA analogues 1–8 exhibited more antibacterial effect against Micrococcus Luteus than gentamicin, but they exhibited moderate antimicrobial activity against the tested bacterial and yeast strains. Molecular docking studies were also simulated for compound 5 to give better rationalization and put insight to the features of its structure.

Issue Information

Quantum dots (QDs) are a novel class of semiconducting nanomaterials with unique properties, including drug delivery systems and biomedical applications. Unsymmetrical bisacridines (UAs), synthesized in our laboratory, patented in Europe [EP 3070078B1] and USA [US 10202349 B2], are a new class of antitumor agents highly active against many experimental cellular and tumor models, including lung, colon, pancreatic and prostate. Here, we investigated whether the conjugation of UAs with QDs has an impact on cytotoxicity and biological response against human lung H460 and colon HCT116 cancer cells, compared to UAs alone. UAs (C-2028 and C-2045) were non-covalently attached to the QDred/green (Ag-In-Zn-S/MUA). The externalization of phosphatidylserine, the decrease of mitochondrial transmembrane potential and the induction of senescence following QDs-UAs treatment at IC80 were examined. Our results indicate that QDs-UAs conjugates exhibited higher cytotoxic activity towards H460 cells than UAs alone, without altering HCT116 cells cytotoxicity. In both cell lines, studied compounds and their conjugates induced apoptotic cell death which reached a higher level in H460 than in HCT116 cells. Interestingly, the number of apoptotic cells (A+/PI+) significantly decreased since 72 h of QDs-C-2028 conjugates treatment compared to C-2028 alone in H460 and HCT116 cells. These results are consistent with the data from mitochondrial transmembrane potential. Furthermore, UAs induced cellular senescence in H460 cells (flattened cells, expression of -galactosidase) and this process was intensified following QDs-UAs conjugates treatment. Surprisingly, the senescence process was not observed in HCT116 cells. Summing up, QDs-UAs nanoconjugates enhanced the cytotoxicity and cellular senescence in H460 cells, but weaken the cellular response (QDs-C-2028) compared to C-2028 alone in both cell lines. These studies were supported by the National Science Center, Poland, UMO-2016/23/B/NZ7/03324.

Quantum Dots as a Good Carriers of Unsymmetrical Bisacridines for Modulating Cellular Uptake and the Biological Response in Lung and Colon Cancer Cells.

Nanotechnology-based drug delivery provides a promising area for improving the efficacy of cancer treatments. Therefore, we investigate the potential of using quantum dots (QDs) as drug carriers for antitumor unsymmetrical bisacridine derivatives (UAs) to cancer cells. We examine the influence of QD–UA hybrids on the cellular uptake, internalization (Confocal Laser Scanning Microscope), and the biological response (flow cytometry and light microscopy) in lung H460 and colon HCT116 cancer cells. We show the time-dependent cellular uptake of QD–UA hybrids, which were more efficiently retained inside the cells compared to UAs alone, especially in H460 cells, which could be due to multiple endocytosis pathways. In contrast, in HCT116 cells, the hybrids were taken up only by one endocytosis mechanism. Both UAs and their hybrids induced apoptosis in H460 and HCT116 cells (to a greater extent in H460). Cells which did not die underwent senescence more efficiently following QDs–UAs treatment, compared to UAs alone. Cellular senescence was not observed in HCT116 cells following treatment with both UAs and their hybrids. Importantly, QDgreen/red themselves did not provoke toxic responses in cancer or normal cells. In conclusion, QDs are good candidates for targeted UA delivery carriers to cancer cells while protecting normal cells from toxic drug activities.

Study of potential anti-carcinogenic and antioxidant effects of plant extracts

One of the main etiological factors in the development of some malignant tumours is the presence of chronic inflammatory processes. A number of biomedical studies have confirmed the anticarcinogenic effect of anti-inflammatory drugs with respect to colon cancers. In addition, some biologically active substances present in medicinal plants have been found to exhibit both anti-carcinogenic and antioxidant activity. In this paper, we investigate potential anticarcinogenic effects of extracts obtained from plant raw materials, including lingonberry (Vaccinium vttis-idaea), raspberry (Rubus idaeus), black chokeberry (Aronia melanocarpa), grape seeds (Vitis L.), grape pomace (Vitis L.), Krasnodar green tea (Camellia sinensis), ginseng (Panax L.), fireweed (Chamaenerion angustifolium) and coffee (Coffea arabica). The effect of these extracts on the growth and viability of colon HCT-116 cancer cells was assessed in vitro using the method of MTT assay. In addition, the effect of non-toxic doses of the extracts under study on the basal and induced levels of pro-inflammatory gene expression - cyclooxygenase (COX2), inducible NO synthase (iNOS) and interleukin 8 (IL8) - was assessed by quantitative PCR. The working concentrations of the extracts under study for HCT-116 cells were determined. It is demonstrated that all investigated extracts are capable of suppressing the expression of COX-2, iNOS and IL-8. Black chokeberry and fireweed extracts exhibit the most pronounced total inhibitory effect on the expression of these inflammatory genes. Future research should investigate effects of black chokeberry and fireweed extracts on the induced expression of COX-2, iNOS and IL-8 and their anti-carcinogenic activity in vivo. The antioxidant activity determined using DPPH and FRAP was the highest for black chokeberry, raspberry and fireweed. A relationship between the anticar-cinogenic and antioxidant effects of the extracts under study was revealed.

Initial experience with novel Embocure Plus microspheres for transarterial chemoembolization (TACE) of liver metastatic colorectal cancer tumours - a clinical and in vitro study.

PurposeTransarterial chemoembolization (TACE) is currently recommended for unresectable intrahepatic tumours with no vascular invasion or metastasis to other organs. It is based on drug-eluting microspheres pre-loaded with chemotherapeutics, which are injected selectively into vessels supplying the tumour, to embolize them inducing ischaemia, and elute the drug, to induce tumour response. We present our initial experience with novel irinotecan- loaded Embocure Plus microspheres in patients with metastatic colorectal cancer tumours in the liver, and their effect on HCT-116 cell cultures in vitro.Material and methodsThree consecutive male patients (median age 62 [50-76] years) with liver metastatic colorectal cancer tumours were selected. All patients had a pre-procedure contrast-enhanced computed tomography, confirming multiple metastatic liver tumours (mean tumour diameter = 42 mm; range: 14-77 mm) and periprocedural dyna-CT scans for rapid treatment results assessment. In vitro: Human colon HCT116 cancer cell line was cultured, irinotecan loaded Embocure Plus microspheres were added. Cultures were assessed after 24 hours and 72 hours of incubation in normoxia or hypoxia.ResultsAll embolizations were technically successful, and no complications were observed. Stabilization of the targeted metastatic liver tumours in all patients was noted. In vitro: Significant decrease of the growth of HTC 116 cell lines were observed in controls compared to cells treated with Embocure Plus loaded with irinotecan in normoxia and hypoxia after 48 and 72 hours. We observed a tendency for less inhibited cell proliferation in low-oxygen conditions.ConclusionsTACE therapy of liver metastatic tumours shows satisfactory results and a low complication rate. Embocure Plus microspheres are safe and technically feasible for superselective chemoembolization of metastatic colorectal cancer liver tumour. Dyna-CT can be used for assessment of treatment results during repeated TACE procedures.

Effect of Lutein-Rich Extract on Human Cancer cells

Background: Lutein and its isomerzeaxanthin are safe natural compounds. They are able to reduce the development of tumor and other chronic diseases. The objectives of the current study was to examine the cytotoxicity of lutein isolated and purified from alfalfa, safe and low-cost plant, on five different human cancer cell lines, namely (MCF-7), (HepG2), (A549), (PC3), and (HCT116), as well as normal (HFB4) cells. Method: We examined the cytotoxicity of lutein purified from Medicago sativa L and evaluate its activity against human liver HepG2, breast MCF-7, lung A549, prostate PC3, and colon HCT116 cancer cell lines using SRB assay in comparison with doxorubicin as a reference drug. Results: Results revealed that the tested extract could be a more promising anticancer agent in the case of MCF-7 (IC50, 3.10±0.47 μg/ml) compared with standard drug doxorubicin (IC50, 2.90±0.30 μg/ml). Moreover, the extract showed a moderate effect on HepG2 (IC50, 6.11±0.84 μg/ml) versus doxorubicin (IC50, 2.90±0.30 μg/ml); meanwhile, the extract showed no activity against A549, PC3, and HCT116 cells. The results further revealed that the extract had no toxicity against the growth of normal HFB4 cells versus doxorubicin. Conclusion: Lutein-rich extract from alfalfa had a major antiproliferative role in breast MCF-7 and liver HepG2 compared to doxorubicin.

PH-responsive and CD44-targeting by Fe3O4/MSNs-NH2 nanocarriers for Oxaliplatin loading and colon cancer treatment

In this work, we have introduced a promising method for performing colon HCT-116 cancer cells treatment by the usage of CD44 to function as the targeting receptors. For this purpose, we have synthesized superparamagnetic Fe3O4/Mesoporous silica nanoparticles (MSNs) through co-precipitation and sol–gel process and had the surface of the obtained nanocarriers (NCs) functionalized by NH2-bonding. The functionalized NCs have been characterized by the means of FT-IR spectroscopy, VSM, TEM, and FE-SEM. In the following, the values of drug loading and release have been measured through the application of ICP-OES analysis for 48 h, in which the drug release profile has been studied in both human blood (pH 7.4) and cancer cell (pH 5.0) conditions. According to the final results of MTT assay, the IC50 of Free drug and NCs -drug loaded has faced a decrease, from 7.5 µg/mL to 3.2 µg/mL, due to the fact that NH2 had been able to express a higher Oxaliplatin intracellular uptake and more CD44-binding than free Oxaliplatin. Therefore, this work has attempted to highlight these Fe3O4/MSNs-NH2 NCs potential in standing as a superior candidate for Oxaliplatin loading and colon cancer treatment.

Enhanced Activity of P4503A4 and UGT1A10 Induced by Acridinone Derivatives C-1305 and C-1311 in MCF-7 and HCT116 Cancer Cells: Consequences for the Drugs' Cytotoxicity, Metabolism and Cellular Response.

Activity modulation of drug metabolism enzymes can change the biotransformation of chemotherapeutics and cellular responses induced by them. As a result, drug-drug interactions can be modified. Acridinone derivatives, represented here by C-1305 and C-1311, are potent anticancer drugs. Previous studies in non-cellular systems showed that they are mechanism-based inhibitors of cytochrome P4503A4 and undergo glucuronidation via UDP-glucuronosyltranspherase 1A10 isoenzyme (UGT1A10). Therefore, we investigated the potency of these compounds to modulate P4503A4 and UGT1A10 activity in breast MCF-7 and colon HCT116 cancer cells and their influence on cytotoxicity and cellular response in cells with different expression levels of studied isoenzymes. We show that C-1305 and C-1311 are inducers of not only P4503A4 but also UGT1A10 activity. MCF-7 and HCT116 cells with high P4503A4 activity are more sensitive to acridinone derivatives and undergo apoptosis/necrosis to a greater extent. UGT1A10 was demonstrated to be responsible for C-1305 and C-1311 glucuronidation in cancer cells and glucuronide products were excreted outside the cell very fast. Finally, we show that glucuronidation of C-1305 antitumor agent enhances its pro-apoptotic properties in HCT116 cells, while the cytotoxicity and cellular response induced by C-1311 did not change after drug glucuronidation in both cell lines.

New Unsymmetrical Bisacridine Derivatives Noncovalently Attached to Quaternary Quantum Dots Improve Cancer Therapy by Enhancing Cytotoxicity toward Cancer Cells and Protecting Normal Cells.

The use of nanoparticles for the controlled drug delivery to cells has emerged as a good alternative to traditional systemic delivery. Quantum dots (QDs) offer potentially invaluable societal benefits such as drug targeting and in vivo biomedical imaging. In contrast, QDs may also pose risks to human health and the environment under certain conditions. Here, we demonstrated that a unique combination of nanocrystals core components (Ag-In-Zn-S) would eliminate the toxicity problem and increase their biomedical applications. The alloyed quaternary nanocrystals Ag-In-Zn-S (QDgreen, Ag1.0In1.2Zn5.6S9.4; QDred, Ag1.0In1.0Zn1.0S3.5) were used to transport new unsymmetrical bisacridine derivatives (UAs, C-2028 and C-2045) into lung H460 and colon HCT116 cancer cells for improving the cytotoxic and antitumor action of these compounds. UAs were coupled with QD through physical adsorption. The obtained results clearly indicate that the synthesized nanoconjugates exhibited higher cytotoxic activity than unbound compounds, especially toward lung H460 cancer cells. Importantly, unsymmetrical bisacridines noncovalently attached to QD strongly protect normal cells from the drug action. It is worth pointing out that QDgreen or QDred without UAs did not influence the growth of cancer and normal cells, which is consistent with in vivo results. In noncellular systems, at pH 5.5 and 4.0, which relates to the conditions of endosomes and lysosomes, the UAs were released from QD-UAs nanoconjugates. An increase of total lysosomes content was observed in H460 cells treated with QDs-UAs which can affect the release of the UAs from the conjugates. Moreover, confocal laser scanning microscopy analyses revealed that QD-UAs nanoconjugates enter H460 cells more efficiently than to HCT116 and normal cells, which may be the reason for their higher cytotoxicity against lung cancer. Summarizing, the noncovalent attachment of UAs to QDs increases the therapeutic efficiency of UAs by improving cytotoxicity toward lung H460 cancer cells and having protecting effects on normal cells.

Hepatoprotective, Antioxidant and Cytotoxic Potential of Aloe niebuhriana Latex Extract from Yemen

The aim of this study was to quantify the total phenolic content of Aloe niebuhriana latex extract and validate its antioxidant, hepatoprotective and cytotoxic activity. The total phenolic content of the extract was estimated spectrophotometrically using Folin Ciocalteu method. The antioxidant activity of the latex extract was determined using 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay. Paracetamol-induced hepatotoxicity rat model was used to evaluate the hepatoprotective activity of the extract. Cytotoxic effect of Aloe niebuhriana latex extract was screened against breast MCF-7, liver HepG2 and colon HCT-116 cancer cell lines using sulphorhodamine B assay. The extract showed high total phenolic content (245.19 mg GAE/g) and strong antioxidant activity (IC50, 19.14 μg/ml). Aloe niebuhriana extract showed significant decrease in alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase, as compared to paracetamol-induced hepatotoxicity model. Hepatoprotective potential of Aloe niebuhriana latex extract was significantly (p<0.05) better than that of the control group and silymarin (100 mg/kg/day). Results of the study were well supported by the histopathological observations. Aloe niebuhriana latex extract exhibited a weak cytotoxicity effect against MCF-7, HepG2 and HCT-116 cancer cell lines. The present results provided evidence that the plant extract inhibited hepatotoxicity induced by paracetamol, which was possibly mediated via free radical scavenging and/or inhibition of free radical generation.

Discovery and optimization of cardenolides inhibiting HSF1 activation in human colon HCT-116 cancer cells.

Combinational anticancer therapy demonstrates increased efficiency, as it targets different cell-survival mechanisms and allows the decrease of drug dosages that are often toxic to normal cells. Inhibitors of the heat shock response (HSR) are known to reduce the efficiency of proteostasis mechanisms in many cancerous cells, and therefore, may be employed as anti-tumor drug complements. However, the application of HSR inhibitors is limited by their cytotoxicity, and we suggested that milder inhibitors may be employed to sensitize cancer cells to a certain drug.We used a heat-shock element-luciferase reporter system and discovered a compound, CL-43, that inhibited the levels of heat shock proteins 40, 70 (Hsp70), and 90 kDa in HCT-116 cells and was not toxic for cells of several lines, including normal human fibroblasts. Consequently, CL-43 was found to reduce colony formation and motility of HCT-116 in the appropriate assays suggesting its possible application in the exploration of biology of metastasizing tumors. Importantly, CL-43 elevated the growth-inhibitory and cytotoxic activity of etoposide, cisplatin, and doxorubicin suggesting that the pro-drug has broad prospect for application in a variety of anti-tumor therapy schedules.

Purification and characterization of a novel thermo stable L-methioninase from Streptomyces sp. DMMMH4 and its evaluation for anticancer activity

L-methioninase has been purified 2.55-fold from the crude extract of Streptomyces sp. DMMMH4. The purification procedure was carried out by heat treatment and gel filtration on Sephadex G-200 column chromatography. SDS-PAGE electrophoresis showed a migrating protein band molecular mass of 48 kDa. The kinetic properties determined for the purified enzyme displayed optimum activity at 70OC and thermal stability was 70OC for 30 min. The enzyme activity showed maximum activity at pH 6 using acetate buffer 0.05M and was relatively stable across a broad range of pH values (5.5-8 pH). The enzyme strongly inhibited by Cr+2, Fe+2, Ni+2, Cd+2, PMSF, β-mercaptoethanol and SDS while Hg+2,Cu+2 and iodoacetate completely inhibited the enzyme activity at a final concentration of 10mM. The purified enzyme exhibited a Km of 0.7, 0.15 and 0.25 mM for L-methionine, DL-ethionine and L-cystine respectively. Cytotoxicity test demonstrate that enzyme was active against liver HepG2, breast MCF-7, lung A549, prostate PC3 and colon HCT116 cancer cell lines and has negligible toxicity toward a normal melanocyte cell line HFB4 .