37 research outputs found
Therapeutic impacts of enzyme-responsive smart nanobiosystems
No full textAn important arena of the sophisticated nanosystems (NSs) is the combination of the responsive features of NSs with the biocatalytic properties of enzymes. The development of such smart drug delivery systems (DDSs) has seminal effectiveness in targeting, imaging, and monitoring of cancer. These NSs can exhibit site-specific delivery of the toxic cargo in response to the endogenous/exogenous stimuli. Enzyme responsive/targeted DDSs display enhanced accumulation of cargo molecules in the tumor microenvironment (TME) with a spatiotemporal controlled-release behavior. Based on the unique features of enzyme responsive/targeted DDSs, they offer incredible promise in overcoming some limitations of the currently used conventional DDSs. Taken all, targeting TME with the enzyme-responsive targeted DDSs may lead to versatile clinical outcomes in various malignancies
Recent advances in targeted therapy of colorectal cancer: impacts of monoclonal antibodies nanoconjugates
No full textDespite rapid advances in diagnostic and treatment approaches, the overall survival rate of cancer has not been improved. Colorectal cancer (CRC) is recognized as the third leading cause of neoplasm-related deaths worldwide, in large part due to its considerable metastasis and drug resistance. For developing new anticancer strategies, rapid progression of multimodal nanomedicines and nanoconjugates has provided promising treatment modalities for effective therapy of cancer. The limitations of cancer chemotherapy might be overcome through the use of such nanosized therapeutics, including nanoconjugates of monoclonal antibodies (mAbs) along with drugs and organic/inorganic nanoparticles. CRC cells express various molecular markers against which mAbs can be designed and used as targeting/therapeutic agents. This editorial highlights the importance of such targeted nanosystems against CRC
Highly efficient novel recombinant L-asparaginase with no glutaminase activity from a new halo-thermotolerant Bacillus strain
No full textIntroduction: The bacterial enzyme has gained more attention in therapeutic application because of the higher substrate specificity and longer half-life. L-asparaginase is an important enzyme with known antineoplastic effect against acute lymphoblastic leukemia (ALL). Methods: Novel L-asparaginase genes were identified from a locally isolated halo-thermotolerant Bacillus strain and the recombinant enzymes were overexpressed in modified E. coli strains, OrigamiTM B and BL21. In addition, the biochemical properties of the purified enzymes were characterized, and the enzyme activity was evaluated at different temperatures, pH, and substrate concentrations. Results: The concentration of pure soluble enzyme obtained from Origami strain was ~30 mg/L of bacterial culture, which indicates the significant improvement compared to L-asparaginase produced by E. coli BL21 strain. The catalytic activity assay on the identified L-asparaginases (ansA1 and ansA3 genes) from Bacillus sp. SL-1 demonstrated that only ansA1 gene codes an active and stable homologue (ASPase A1) with high substrate affinity toward L-asparagine. The Kcat and Km values for the purified ASPase A1 enzyme were 23.96s-1 and 10.66 µM, respectively. In addition, the recombinant ASPase A1 enzyme from Bacillus sp. SL-1 possessed higher specificity to L-asparagine than L-glutamine. The ASPase A1 enzyme was highly thermostable and resistant to the wide range of pH 4.5–10. Conclusion: The biochemical properties of the novel ASPase A1 derived from Bacillus sp. SL-l indicated a great potential for the identified enzyme in pharmaceutical and industrial applications
Identification and Molecular Characterization of Genes Coding Pharmaceutically Important Enzymes from Halo-Thermo Tolerant Bacillus
No full textPurpose: Robust pharmaceutical and industrial enzymes from extremophile
microorganisms are main source of enzymes with tremendous stability under harsh
conditions which make them potential tools for commercial and biotechnological
applications.
Methods: The genome of a Gram-positive halo-thermotolerant Bacillus
sp. SL1, new isolate from Saline Lake, was investigated for the presence of
genes coding for potentially pharmaceutical enzymes. We determined gene sequences for the enzymes laccase
(CotA), l-asparaginase (ansA3, ansA1), glutamate-specific endopeptidase
(blaSE), l-arabinose isomerase (araA2), endo-1,4-β mannosidase (gmuG),
glutaminase (glsA), pectate lyase (pelA), cellulase (bglC1), aldehyde
dehydrogenase (ycbD) and allantoinases (pucH) in the genome of Bacillus
sp. SL1.
Results: Based on the DNA sequence alignment results, six of
the studied enzymes of Bacillus sp. SL-1 showed 100% similarity at the
nucleotide level to the same genes of B. licheniformis 14580
demonstrating extensive organizational relationship between these two strains.
Despite high similarities between the B. licheniformis and Bacillus
sp. SL-1 genomes, there are minor differences in the sequences of some enzyme.
Approximately 30% of the enzyme sequences revealed more than 99% identity with some
variations in nucleotides leading to amino acid substitution in protein
sequences.
Conclusion: Molecular characterization
of this new isolate provides useful information regarding evolutionary
relationship between B. subtilis and
B. licheniformis species. Since, the most industrial processes are
often performed in harsh conditions, enzymes from such halo-thermotolerant
bacteria may provide economically and industrially appealing biocatalysts to be
used under specific physicochemical situations in medical, pharmaceutical,
chemical and other industries
Enzyme replacement therapies: What is the best option?
No full textDespite many beneficial outcomes of the conventional enzyme replacement therapy (ERT), several limitations such as the high-cost of the treatment and various inadvertent side effects including the occurrence of an immunological response against the infused enzyme and development of resistance to enzymes persist. These issues may limit the desired therapeutic outcomes of a majority of the lysosomal storage diseases (LSDs). Furthermore, the biodistribution of the recombinant enzymes into the target cells within the central nervous system (CNS), bone, cartilage, cornea, and heart still remain unresolved. All these shortcomings necessitate the development of more effective diagnosis and treatment modalities against LSDs. Taken all, maximizing the therapeutic response with minimal undesired side effects might be attainable by the development of targeted enzyme delivery systems (EDSs) as a promising alternative to the LSDs treatments, including different types of mucopolysaccharidoses (MPSs ) as well as Fabry, Krabbe, Gaucher and Pompe diseases
Highly efficient novel recombinant L-asparaginase with no glutaminase activity from a new halo-thermotolerant Bacillus strain
No full textIntroduction: The bacterial enzyme has gained more attention in therapeutic application because of the higher substrate specificity and longer half-life. L-asparaginase is an important enzyme with known antineoplastic effect against acute lymphoblastic leukemia (ALL). Methods: Novel L-asparaginase genes were identified from a locally isolated halo-thermotolerant Bacillus strain and the recombinant enzymes were overexpressed in modified E. coli strains, OrigamiTM B and BL21. In addition, the biochemical properties of the purified enzymes were characterized, and the enzyme activity was evaluated at different temperatures, pH, and substrate concentrations. Results: The concentration of pure soluble enzyme obtained from Origami strain was ~30 mg/L of bacterial culture, which indicates the significant improvement compared to L-asparaginase produced by E. coli BL21 strain. The catalytic activity assay on the identified L-asparaginases (ansA1 and ansA3 genes) from Bacillus sp. SL-1 demonstrated that only ansA1 gene codes an active and stable homologue (ASPase A1) with high substrate affinity toward L-asparagine. The Kcat and Km values for the purified ASPase A1 enzyme were 23.96s-1 and 10.66 µM, respectively. In addition, the recombinant ASPase A1 enzyme from Bacillus sp. SL-1 possessed higher specificity to L-asparagine than L-glutamine. The ASPase A1 enzyme was highly thermostable and resistant to the wide range of pH 4.5�10. Conclusion: The biochemical properties of the novel ASPase A1 derived from Bacillus sp. SL-l indicated a great potential for the identified enzyme in pharmaceutical and industrial applications. © 2019 The Author(s)
Improved Biological Impacts of Anti-EGFR Monoclonal Antibody in KRAS-Mutant Colorectal Cancer Cells by Silica-Coated Magnetic Nanoparticle Conjugation
No full textBackground: The therapeutic potential of epidermal growth factor receptor (EGFR) targeting in colorectal cancer (CRC) is hindered by the presence of KRAS codon 12 activating mutations, prevalent in approximately 25% of advanced CRC cases. This study investigates the role of reactive oxygen species (ROS) in conferring resistance to anti-EGFR monoclonal antibodies in KRAS mutant CRC cells, focusing on ROS-mediated apoptosis induction using cetuximab-PEGylated silica-coated magnetic nanoparticles (MNPs). Methods: MNPs were synthesized and surface-coated with silica, followed by functionalization and stabilization with polyethylene glycol (PEG). Cetuximab (Cet) was covalently conjugated to generate EMNP-PEG-Cet. Structural and compositional analyses were performed using scanning electron microscopy (SEM), dynamic light scattering (DLS), UV-vis spectroscopy, and Fourier transform infrared (FTIR) analysis. Apoptosis induction, chromatin condensation, and ROS production were evaluated in KRAS mutant SW-480 CRC cells. Results: Successful synthesis of EMNP-PEG-Cet was confirmed, revealing a particle size of 67 nm and a surface charge of -8.3 mV. The conjugate exhibited significant cytotoxicity against CRC cells, with notable apoptosis induction and ROS generation in EGFR-positive/KRAS mutant SW-480 cells, surpassing the effects observed with bare Cet and EMNP-PEG controls. The nuclear factor erythroid 2-related factor 2/Kelch-like ECH-related protein 1 (Nrf2-Kaep1) gene expression analysis by real-time PCR showed that cells treated with EMNP-PEG-Cet exhibited a noteworthy decrease in Nrf2 expression and a simultaneous increase in Keap1 expression compared to those treated with free Cet. Conclusion: These findings highlight the potential of ROS-mediated apoptosis induction to enhance the cytotoxicity of Cet in EGFR-positive/KRAS mutant CRC cells, offering new avenues for overcoming drug resistance mechanisms in metastatic CRC
EGFR-targeting RNase A-cetuximab antibody-drug conjugate induces ROS-mediated apoptosis to overcome drug resistance in KRAS mutant cancer cells
No full textAbstract Antibody-drug conjugates (ADCs) are an emerging strategy in cancer therapy, enhancing precision and efficacy by linking targeted antibodies to potent cytotoxic agents. This study introduces a novel ADC that combines ribonuclease A (RNase A) with cetuximab (Cet), an anti-EGFR monoclonal antibody, through a polyethylene glycol (PEG) linker (RN-PEG-Cet), aimed to induce apoptosis in KRAS mutant colorectal cancer (CRC) via a ROS-mediated pathway. RN-PEG-Cet was successfully synthesized and characterized for its physicochemical properties, retaining full enzymatic activity in RNA degradation and high binding affinity to EGFR. In KRAS mutant SW-480 cells, RN-PEG-Cet significantly reduced cell viability at lower doses, with an IC50 of 11.7 µg/mL at 72 h. Compared to free Cet, RN-PEG-Cet demonstrated a ~ 2-fold increase in apoptosis and a ~ 3.5-fold increase in ROS production. The conjugate also disrupted the Nrf2/Keap1 pathway, with a significant upregulation of Keap1 (FC = 3.7, p ≤ 0.01) and downregulation of Nrf2 (FC = 3.3, p < 0.01), highlighting its role in impairing antioxidant defenses and promoting ROS-mediated cytotoxicity. These findings emphasize the potential of RN-PEG-Cet as a novel therapeutic approach for KRAS mutant CRC, offering superior apoptosis induction and targeted cytotoxicity compared to conventional therapies. This ADC could represent a new strategy for improving CRC treatment outcomes by effectively overcoming resistance mechanisms
The Synthetic Antimicrobial Peptide Derived From Melittin Displays Low Toxicity and Anti-infectious Properties
No full textThe low stability and nonspecific toxicity are the main limiting factors for the clinical applications of melittin (MLT). This study aimed to design and synthesize new analogs of MLT to increase stability, reduce toxicity, and retain their antimicrobial properties against bacterial pathogens. At first, peptide analogs were designed computationally by inducing single mutations in MLT peptides and evaluating their physicochemical properties. The stability of the analogs with the highest scores was determined by Gromacs software. In vitro assays were performed to examine the antimicrobial activity and toxicity of the selected analogs. Two peptide analogs, M1 and M2, were selected based on the SVM score in cell PPD. The M1 analog was created by replacing alanine with leucine on the 15th. The M2 analog was designed by substituting alanine with leucine and isoleucine with arginine at the 15th and 17th positions. According to the Gromacs results, the M2 peptide indicated more stability. RMSD and RMSF results showed no undesirable fluctuations during the 200 ns MD simulation. The MIC and MBC values for the M1 peptide were calculated in a range of 8–128 μg/ml, while the M2 peptide limited the bacterial growth to 32–128 μg/mL. Both peptides indicated less toxicity than natural MLT, based on MTT assay results. The hemolytic activity of the M1 analog was more than M2 at 16 μg/mL concentration. M1 peptide displayed the highest selectivity index against S. aureus and A. baumannii, which were approximately 5.27-fold improvements compared to MLT. In conclusion, we introduced two analogs of MLT with low toxicity, low hemolytic activity, and higher stability, along with retaining antimicrobial properties against gram-negative and positive bacteria
Univermy of Wkconsir, Press. What is a Citation Worth?
No full textA robust finding in all studies is that citadons are a positive and significant &terndnant of eam”ngs over almost all of theobserved range of citation levefs. lhe marginal value of a citation (when ths level of a“[atiom is zero) varies between 1,3fX3. Same differences in marginal values may be due to differences in citation practices among disciplines while others may be due to differences among the studies in ths control variables included in the safary regressions. Finally, no gain in explanatory power results from the inchsion in the salary regression of the costly nonfirst-author citadon measure. I. Introduction No consensus yet exists on the economic significance of citations. Some (e.g., Cole and Cole Atthough exceptions are common, the main func- 1%7) have argued that citations can be viewed tion of most citations is to refer tfre reader to im- as a form of recognition and hence are a nonpeportant work relevant to the paper and to credit cuniary reward for scientific activity. Others (e.g.
