The Modified Heparin-Binding L-Asparaginase of Wolinella succinogenes

L-Asparaginase Conjugates from the Hyperthermophilic Archaea Thermococcus sibiricus with Improved Biocatalytic Properties

This study investigated the effect of polycationic and uncharged polymers (and oligomers) on the catalytic parameters and thermostability of L-asparaginase from Thermococcus sibiricus (TsA). This enzyme has potential applications in the food industry to decrease the formation of carcinogenic acrylamide during the processing of carbohydrate-containing products. Conjugation with the polyamines polyethylenimine and spermine (PEI and Spm) or polyethylene glycol (PEG) did not significantly affect the secondary structure of the enzyme. PEG contributes to the stabilization of the dimeric form of TsA, as shown by HPLC. Furthermore, neither polyamines nor PEG significantly affected the binding of the L-Asn substrate to TsA. The conjugates showed greater maximum activity at pH 7.5 and 85 °C, 10-50% more than for native TsA. The pH optima for both TsA-PEI and TsA-Spm conjugates were shifted to lower pH ranges from pH 10 (for the native enzyme) to pH 8.0. Additionally, the TsA-Spm conjugate exhibited the highest activity at pH 6.5-9.0 among all the samples. Furthermore, the temperature optimum for activity at pH 7.5 shifted from 90-95 °C to 80-85 °C for the conjugates. The thermal inactivation mechanism of TsA-PEG appeared to change, and no aggregation was observed in contrast to that of the native enzyme. This was visually confirmed and supported by the analysis of the CD spectra, which remained almost unchanged after heating the conjugate solution. These results suggest that TsA-PEG may be a more stable form of TsA, making it a potentially more suitable option for industrial use.

Synthesis of biologically active proteins as L6KD-SUMO fusions forming inclusion bodies in Escherichia coli

A new platform has been developed to facilitate the production of biologically active proteins and peptides in Escherichia coli. The platform includes an N-terminal self-associating L6 KD peptide fused to the SUMO protein (small ubiquitin-like protein modifier) from the yeast Saccharomyces cerevisiae, which is known for its chaperone activity. The target proteins are fused at the C termini of the L6 KD-SUMO fusions, and the resulting three-component fusion proteins are synthesized and self-assembled in E. coli into so-called active inclusion bodies (AIBs). In vivo, the L6 KD-SUMO platform facilitates the correct folding of the target proteins and directs them into AIBs, greatly simplifying their purification. In vitro, the platform facilitates the effective separation of AIBs by centrifugation and subsequent target protein release using SUMO-specific protease. The properties of the AIBs were determined using five proteins with different sizes, folding efficiencies, quaternary structure, and disulfide modifications. Electron microscopy shows that AIBs are synthesized in the form of complex fibrillar structures resembling "loofah sponges" with unusually thick filaments. The obtained results indicate that the new platform has promising features and could be developed to facilitate the synthesis and purification of target proteins and protein complexes without the use of renaturation.

Enzyme Engineering Strategies for the Bioenhancement of L-Asparaginase Used as a Biopharmaceutical

Over the past few years, there has been a surge in the industrial production of recombinant enzymes from microorganisms due to their catalytic characteristics being highly efficient, selective, and biocompatible. L-asparaginase (L-ASNase) is an enzyme belonging to the class of amidohydrolases that catalyzes the hydrolysis of L-asparagine into L-aspartic acid and ammonia. It has been widely investigated as a biologic agent for its antineoplastic properties in treating acute lymphoblastic leukemia. The demand for L-ASNase is mainly met by the production of recombinant type II L-ASNase from Escherichia coli and Erwinia chrysanthemi. However, the presence of immunogenic proteins in L-ASNase sourced from prokaryotes has been known to result in adverse reactions in patients undergoing treatment. As a result, efforts are being made to explore strategies that can help mitigate the immunogenicity of the drug. This review gives an overview of recent biotechnological breakthroughs in enzyme engineering techniques and technologies used to improve anti-leukemic L-ASNase, taking into account the pharmacological importance of L-ASNase.

Current state of molecular and metabolic strategies for the improvement of L-asparaginase expression in heterologous systems

Heterologous expression of L-asparaginase (L-ASNase) has become an important area of research due to its clinical and food industry applications. This review provides a comprehensive overview of the molecular and metabolic strategies that can be used to optimize the expression of L-ASNase in heterologous systems. This article describes various approaches that have been employed to increase enzyme production, including the use of molecular tools, strain engineering, and in silico optimization. The review article highlights the critical role that rational design plays in achieving successful heterologous expression and underscores the challenges of large-scale production of L-ASNase, such as inadequate protein folding and the metabolic burden on host cells. Improved gene expression is shown to be achievable through the optimization of codon usage, synthetic promoters, transcription and translation regulation, and host strain improvement, among others. Additionally, this review provides a deep understanding of the enzymatic properties of L-ASNase and how this knowledge has been employed to enhance its properties and production. Finally, future trends in L-ASNase production, including the integration of CRISPR and machine learning tools are discussed. This work serves as a valuable resource for researchers looking to design effective heterologous expression systems for L-ASNase production as well as for enzymes production in general.

[Approaches for improving L-asparaginase expression in heterologous systems]

L-asparaginase (EC 3.5.1.1) is one of the most demanded enzymes used in the pharmaceutical industry as a drug and in the food industry to prevent the formation of toxic acrylamide. Researchers aimed to improve specific activity and reduce side effects to create safer and more potent enzyme products. However, protein modifications and heterologous expression remain problematic in the production of asparaginases from different species. Heterologous expression in optimized producer strains is rationally organized; therefore, modified and heterologous protein expression is enhanced, which is the main strategy in the production of asparaginase. This strategy solves several problems: incorrect protein folding, metabolic load on the producer strain and codon misreading, which affects translation and final protein domains, leading to a decrease in catalytic activity. The main approaches developed to improve the heterologous expression of L-asparaginases are considered in this paper.

Predictive markers for efficiency of the amino-acid deprivation therapies in cancer

Amino acid deprivation therapy (AADT) is a promising strategy for developing novel anticancer treatments, based on variations in metabolism of healthy and malignant cells. L-asparaginase was the first amino acid-degrading enzyme that received FDA approval for the treatment of acute lymphoblastic leukemia (ALL). Arginase and arginine deiminase were effective in clinical trials for the treatment of metastatic melanomas and hepatocellular carcinomas. Essential dependence of certain cancer cells on methionine explains the anticancer efficacy of methionine-g-lyase. Along with significant progress in identification of metabolic vulnerabilities of cancer cells, new amino acid-cleaving enzymes appear as promising agents for cancer treatment: lysine oxidase, tyrosine phenol-lyase, cysteinase, and phenylalanine ammonia-lyase. However, sensitivity of specific cancer cell types to these enzymes differs. Hence, search for prognostic and predictive markers for AADT and introduction of the markers into clinical practice are of great importance for translational medicine. As specific metabolic pathways in cancer cells are determined by the enzyme expression, some of these enzymes may define the sensitivity to AADT. This review considers the known predictors for efficiency of AADT, emphasizing the importance of knowledge on cancer-specific amino acid significance for such predictions.

L-Asparaginase from Penicillium sizovae Produced by a Recombinant Komagataella phaffii Strain

L-asparaginase is an important enzyme in the pharmaceutical field used as treatment for acute lymphoblastic leukemia due to its ability to hydrolyze L-asparagine, an essential amino acid synthesized by normal cells, but not by neoplastic cells. Adverse effects of L-asparaginase formulations are associated with its glutaminase activity and bacterial origin; therefore, it is important to find new sources of L-asparaginase produced by eukaryotic microorganisms with low glutaminase activity. This work aimed to identify the L-asparaginase gene sequence from Penicillium sizovae, a filamentous fungus isolated from the Brazilian Savanna (Cerrado) soil with low glutaminase activity, and to biosynthesize higher yields of this enzyme in the yeast Komagataella phaffii. The L-asparaginase gene sequence of P. sizovae was identified by homology to L-asparaginases from species of Penicillium of the section Citrina: P. citrinum and P. steckii. Partial L-asparaginase from P. sizovae, lacking the periplasmic signaling sequence, was cloned, and expressed intracellularly with highest enzymatic activity achieved by a MUT⁺ clone cultured in BMM expression medium; a value 5-fold greater than that obtained by native L-asparaginase in P. sizovae cells. To the best of our knowledge, this is the first literature report of the heterologous production of an L-asparaginase from a filamentous fungus by a yeast.

Molecular Analysis of L-Asparaginases for Clarification of the Mechanism of Action and Optimization of Pharmacological Functions

L-asparaginases (EC 3.5.1.1) are a family of enzymes that catalyze the hydrolysis of L-asparagine to L-aspartic acid and ammonia. These proteins with different biochemical, physicochemical and pharmacological properties are found in many organisms, including bacteria, fungi, algae, plants and mammals. To date, asparaginases from E. coli and Dickeya dadantii (formerly known as Erwinia chrysanthemi) are widely used in hematology for the treatment of lymphoblastic leukemias. However, their medical use is limited by side effects associated with the ability of these enzymes to hydrolyze L-glutamine, as well as the development of immune reactions. To solve these issues, gene-editing methods to introduce amino-acid substitutions of the enzyme are implemented. In this review, we focused on molecular analysis of the mechanism of enzyme action and to optimize the antitumor activity.

Circumventing the side effects of L-asparaginase

L-asparaginase is an enzyme that catalyzes the degradation of asparagine and successfully used in the treatment of acute lymphoblastic leukemia. L-asparaginase toxicity is either related to hypersensitivity to the foreign protein or to a secondary L-glutaminase activity that causes inhibition of protein synthesis. PEGylated versions have been incorporated into the treatment protocols to reduce immunogenicity and an alternative L-asparaginase derived from Dickeya chrysanthemi is used in patients with anaphylactic reactions to the E. coli L-asparaginase. Alternative approaches commonly explore new sources of the enzyme as well as the use of protein engineering techniques to create less immunogenic, more stable variants with lower L-glutaminase activity. This article reviews the main strategies used to overcome L-asparaginase shortcomings and introduces recent tools that can be used to create therapeutic enzymes with improved features.

Plasma pharmacokinetics and tissue distribution of L-lysine α-oxidase from Trichoderma cf. aureoviride RIFAI VKM F- 4268D in mice

L-lysine α-oxidase (LO) is an L-amino acid oxidase with antitumor, antimicrobial and antiviral properties. Pharmacokinetic (PK) studies were carried out by measuring LO concentration in plasma and tissue samples by enzyme immunoassay. L-lysine concentration in samples was measured spectrophotometrically using LO. After single i.v. injection of 1.0, 1.5, 3.0 mg/kg the circulating T_1/2 of enzyme in mice varied from 51 to 74 min and the AUC_0-inf values were 6.54 ± 0.46, 8.66 ± 0.59, 9.47 ± 1.45 μg/ml × h, respectively. LO was distributed in tissues and determined within 48 h after administration with maximal accumulation in liver and heart tissues. Mean time to reach the maximum concentration was highest for the liver-9 h, kidney-1 h and 15 min for the tissues of heart, spleen and brain. T_1/2 of LO in tissues ranged from 7.75 ± 0.73 to 26.10 ± 2.60 h. In mice, plasma L-lysine decreased by 79% 15 min after LO administration in dose 1.6 mg/kg. The serum L-lysine levels remained very low from 1 to 9 h (< 25 μM, 17%), indicating an acute lack of L-lysine in animals for at least 9 h. Concentration of L-lysine in serum restored only 24 h after LO administration. The results of LO PK study show that it might be considered as a promising enzyme for further investigation as a potential anticancer agent.

Penetration into Cancer Cells via Clathrin-Dependent Mechanism Allows L-Asparaginase from Rhodospirillum rubrum to Inhibit Telomerase

The anticancer effect of L-asparaginases (L-ASNases) is attributable to their ability to hydrolyze L-asparagine in the bloodstream and cancer cell microenvironment. Rhodospirillum rubrum (RrA) has dual mechanism of action and plays a role in the suppression of telomerase activity. The aim of this work was to investigate the possible mechanism of RrA penetration into human cancer cells. Labeling of widely used L-ASNases by fluorescein isothiocyanate followed by flow cytometry and fluorescent microscopy demonstrated that only RrA can interact with cell membranes. The screening of inhibitors of receptor-mediated endocytosis demonstrated the involvement of clathrin receptors in RrA penetration into cells. Confocal microscopy confirmed the cytoplasmic and nuclear localization of RrA in human breast cancer SKBR3 cells. Two predicted nuclear localization motifs allow RrA to penetrate into the cell nucleus and inhibit telomerase. Chromatin relaxation promoted by different agents can increase the ability of RrA to suppress the expression of telomerase main catalytic subunit. Our study demonstrated for the first time the ability of RrA to penetrate into human cancer cells and the involvement of clathrin receptors in this process.

Methionine Gamma Lyase from Clostridium sporogenes Increases the Anticancer Efficacy of Doxorubicin on A549 Cancer Cells In Vitro and Human Cancer Xenografts

The anticancer efficacy of methionine γ-lyase (MGL) from Clostridium sporogenes (C. sporogenes) is described. MGL was active against cancer cells in vitro and in vivo. Doxorubicin (DOX) and MGL were more effective on A549 human lung-cancer growth inhibition than either agent alone in vitro and in vivo.

Amino Acid Degrading Enzymes and their Application in Cancer Therapy

BACKGROUND

Amino acids are essential components in various biochemical pathways. The deprivation of certain amino acids is an antimetabolite strategy for the treatment of amino acid-dependent cancers which exploits the compromised metabolism of malignant cells. Several studies have focused on the development and preclinical and clinical evaluation of amino acid degrading enzymes, namely L-asparaginase, L-methionine γ-lyase, L-arginine deiminase, L-lysine α-oxidase. Further research into cancer cell metabolism may therefore define possible targets for controlling tumor growth.

OBJECTIVE

The purpose of this review was to summarize recent progress in the relationship between amino acids metabolism and cancer therapy, with a particular focus on Lasparagine, L-methionine, L-arginine and L-lysine degrading enzymes and their formulations, which have been successfully used in the treatment of several types of cancer.

METHODS

We carried out a structured search among literature regarding to amino acid degrading enzymes. The main aspects of search were in vitro and in vivo studies, clinical trials concerning application of these enzymes in oncology.

RESULTS

Most published research are on the subject of L-asparaginase properties and it's use for cancer treatment. L-arginine deiminase has shown promising results in a phase II trial in advanced melanoma and hepatocellular carcinoma. Other enzymes, in particular Lmethionine γ-lyase and L-lysine α-oxidase, were effective in vitro and in vivo.

CONCLUSION

The findings of this review revealed that therapy based on amino acid depletion may have the potential application for cancer treatment but further clinical investigations are required to provide the efficacy and safety of these agents.

Defining the toxicity of current regimens for extranodal NK/T cell lymphoma: a systematic review and metaproportion

Objectives: The aim of this study is to compare the toxicity profiles of SMILE versus less intense L-asparaginase-containing regimens, CCRT or "sandwich" RT+CT regimens. Methods: PRISMA protocol was used to search Pubmed and Embase for studies of treatment regimens for extranodal NK/T-cell lymphoma, nasal type (ENKTL) in English published before March 2018. Pooled data were grouped into five categories: A) CHOP-like regimens; B) Gemcitabine-based regimens; C) SMILE-like regimens; D) Concurrent and "sandwich" RT + CT; and E) Methotrexate-based combinations. We pooled prevalence of selected adverse events from each study to calculate the weighted overall prevalence using meta-proportion in Stata. Results: Group C was the most toxic with the pooled neutropenia 72% (95 CI 64;80) and thrombocytopenia 48% (95% CI 40;55) prevalence. The use of Group D treatment regimens was associated with the lowest anemia (10% (95% CI 1;19)) prevalence. Group E was the least toxic with regard to thrombocytopenia (6% (95% CI 1;11). Conclusion: Our analysis confirms that SMILE regimen, which is current standard to treat advanced-stage ENKTL may be associated with more severe hematological toxicity compared to other L-asparaginase combinations, including methotrexate-based (AspaMetDex, MESA and MEDA) or gemcitabine-based (GELOX, PGEMOX, DDGP, GDL, GOLD, GLIDE) or CCRT-based regimens.

Methionine gamma lyase from Clostridium sporogenes increases the anticancer effect of doxorubicin in A549 cells and human cancer xenografts

The anti-cancer efficacy of methionine γ-lyase (MGL) from Clostridium sporogenes (C. sporogenes) is described. MGL was active against cancer models in vitro and in vivo. The calculated EC50 values for MGL were 4.4 U/ml for A549, 7.5 U/ml for SK-BR3, 2.4 U/ml for SKOV3, and 0.4 U/ml for MCF7 cells. The combination of doxorubicin (DOX) and MGL was more effective for A549 human lung cancer growth inhibition than either agent alone in vitro and in vivo. MGL reduced the EC50 of doxorubicin from 35.9 μg/mL to 0.01-0.265 μg/mL. The growth inhibitory effect of DOX + MGL on A549 xenografts in vivo was reflective of the results obtained in vitro. The inhibition rate of tumor growth in the combined arm was 57%, significantly higher than that in the doxorubicin (p = 0.033)-alone arm.

Genetic and metabolic engineering approaches for the production and delivery of L-asparaginases: An overview

L-asparaginase is one of the protein drugs for countering leukemia and lymphoma. A major challenge in the therapeutic potential of the enzyme is its immunogenicity, low-plasma half-life and glutaminase activity that are found to be the reasons for toxicities attributed to asparaginase therapy. For addressing these challenges, several research and developmental activities are going on throughout the world for an effective drug delivery for treatment of cancer. Hence there is an urgent need for the development of asparaginase with improved properties for efficient drug delivery. The strategies selected should be economically viable to ensure the availability of the drug at low cost. The current review addresses various strategies adopted for the production of asparaginase from different sources, approaches for increasing the therapeutic efficiency of the protein and new drug delivery systems for L-asparaginase.

Rhodospirillum rubruml-asparaginase targets tumor growth by a dual mechanism involving telomerase inhibition

Rhodospirillum rubruml-asparaginase mutant RrA E149R, V150P, F151T (RrA) was previously identified to down-regulate telomerase activity along with catalyzing the hydrolysis of l-asparagine. The aim of this study was to define the effect of prolonged RrA exposure on telomerase activity, maintenance of telomeres and proliferation of cancer cells in vitro and in vivo. RrA could inhibit telomerase activity in SCOV-3, SkBr-3 and A549 human cancer cell lines due to its ability to down-regulate the expression of telomerase catalytic subunit hTERT. Telomerase activity in treated cells did not exceeded 29.63 ± 12.3% of control cells. Continuous RrA exposure of these cells resulted in shortening of telomeres followed by cell death in vitro. Using real time PCR we showed that length of telomeres in SCOV-3 cells has been gradually decreasing from 10105 ± 2530 b.p. to 1233 ± 636 b.p. after 35 days of cultivation. RrA treatment of xenograft models in vivo showed slight inhibition of tumor growth accompanied with 49.5-53.3% of decrease in hTERT expression in the all tumors. However down-regulation of hTERT expression, inhibition of telomerase activity and the loss of telomeres was significant in response to RrA administration in xenograft models. These results should facilitate further investigations of RrA as a potent therapeutic protein.

L-Asparaginase for newly diagnosed extra-nodal NK/T-cell lymphoma: systematic review and meta-analysis

OBJECTIVES

The aim of this review was to compare the efficacy of asparaginase (ASP)-containing vs ASP-absent regimens in the first-line treatment of ENKTL patients.

METHODS

The PRISMA protocol was used to search PubMed and Embase for both controlled and uncontrolled studies of ASP or alternative chemotherapy (CT) for newly diagnosed ENKTL, published in English by March 2017. The regimens were compared to calculate relative risk (RR) with 95% confidence interval (CI) of the overall response rate (ORR), complete response (CR) or partial response (PR).

RESULTS

Out of 38 studies included, eight were controlled trials, with the pooled RR of ORR in stage I-II 1.54 (95% CI 1.34-1.77); stage I-IV 1.34 (95% CI 1.09-1.64). In stage III-IV CT combined with radiotherapy (RT), RR of ORR was 2.30 (95% CI 1.66-3.18). ASP was also superior in achieving CR. When all single arms combined, RR of ORR after CT with ASP was 1.52 (95% CI 1.38-1.67) in stage I-II (15 studies); 1.44 (95% CI 1.32-1.57) in all stages (29 studies); 1.31 (95% CI 1.24-1.38) and 1.66 (95% CI 1.18-2.34) in stages I-II and III-IV combined with RT, correspondingly.

CONCLUSIONS

ASP-based CT significantly improved ORR and CR in patients with newly diagnosed both early-stage and advanced-stage ENKTL.

Suppression of telomerase activity leukemic cells by mutant forms of Rhodospirillum rubrum L-asparaginase

The active and stable mutant forms of short chain cytoplasmic L-asparaginase type I of Rhodospirillum rubrum (RrA): RrA+N17, D60K, F61L, RrA+N17, A64V, E67K, RrA+N17, E149R, V150P, RrAE149R, V150P and RrAE149R, V150P, F151T were obtained by the method of site-directed mutagenesis. It is established that variants RrA-N17, E149R, V150P, F151T and RrАE149R, V150P are capable to reduce an expression hTERT subunit of telomerase and, hence, activity of telomeres in Jurkat cells, but not in cellular lysates. During too time, L-asparaginasеs of Escherichia coli, Erwinia carotovora and Wolinella succinogenes, mutant forms RrА+N17, D60K, F61L and RrА+N17, A64V, E67K do not suppress of telomerase activity. The assumption of existence in structure RrA of areas (amino acids residues in the position 146-164, 1-17, 60-67) which are responsible for suppression of telomerase activity is made. The received results show that antineoplastic activity of some variants RrA is connected both with reduction of concentration of free L-asparagine, and with expression suppression of hTERT telomerase subunit, that opens new prospects for antineoplastic therapy.