Showing 7 results for shahangian
Shirin Jalili, Sadegh Hasannia, Shirin shahangian, , , , , ,
Volume 4, Issue 2 (9-2013)
Abstract
One of the most promising strategies in cancer therapy is to induce apoptotic pathway. For this purpose, several constructed agonists of Death Receptor 5 (DR5) are in clinical development. Extrinsic and intrinsic apoptosis pathways of various cancer cells are primarily induced through the activation of the proapoptotic DR5. The extracellular domain of DR5 is comprised of several functional domains, among them the cysteine-rich domains (CRDs) play a critical role in TRAIL-DR5-mediated apoptosis. It has recently been shown that the binding of agonistic monoclonal antibody to another N-terminal domain of DR5 could mediate its activation and apoptosis induction. Variable domains derived from heavy chain antibodies (hcAb) called VHHs or nanobodies are robust, efficient and smallest antigen binding fragments. These unique features of VHHs make them potential therapeutic and diagnostic candidates. In the present study, using phage display technology, a library containing VHH genes was generated of an immunized camel with hapten-peptide 1ITQQDLAPQQRA12 and used to isolate the binders of this peptide. Through screening the phage library, three binders with high binding ability to desired epitope in the NTR region were obtained. Considering to the key role of this epitope in apoptosis inducing, these selected binders could be potential candidates to trigger apoptosis in various cancer cells.
S. Shirin shahangian, Shirin Jalili, Ammar Mohseni, Reza Hassan Sajedi, Sadegh Hasannia, Majid Taghdir, Mohammad Mohammadi, Rayhaneh Sariri,
Volume 5, Issue 1 (11-2014)
Abstract
Regarding the importance of inhibiting VEGF and unique features of VHHs as a new generation of antibody-based therapeutics, the present study aimed to generate VHHs against the receptor binding domain of VEGF, thereby blocking of VEGF binding to its receptor. After preparing the gene repertoire of VHH fragments from an immunized camel, a VHH phage display library was constructed. We adopted a stringent successive biopanning to isolate the phages displaying VHH with high affinity to VEGF-RBD.A significant enrichment of phages that specifically bound to the target protein was obtained after six rounds of panning. Of the specific clones with high binding affinity screened by monoclonal phage ELISA, 52% shared the same VHH sequence, showing its high enrichment. Using molecular simulation of antigen-antibody interaction based on the crystallographic information of VEGF/VEGFR2, molecular dynamics simulations and MM/PBSA free energy calculations, we provide a reliable picture of the binding site of antibody on antigen. The key residues in the VEvhh1-VEGF interface were dissected and the energetics was analyzed by MM/PBSA. The results of studies revealed that VEvhh1 binds to the receptor binding site of VEGF with high binding energy and showed the highest affinity to the residues of VEGF which are responsible for VEGF binding to VEGFR2. Also the antibody potently covers these key functional residues of VEGF, thereby inhibiting VEGF binding to its receptor and probably abrogating its biological activity. This study may represent VEvhh1 as an anti-VEGF and anti-angiogenic candidate.
Volume 7, Issue 3 (Summer 2019)
Abstract
Aims: Breast cancer is the most common cancer in women in several countries. Bioactive peptides have demonstrated their cytotoxic potential in numerous cancer cell lines. In the search for novel bioactive peptides for pharmacological properties, crab is noncommercial protein-rich species. Using enzymatic hydrolysis is an efficient way to recover potent bioactive peptides from marine sources.
Materials and Methods: The aim of this study was to isolate fractions from rocky shore crab hydrolysate with desired molecular weight by ultrafiltration and investigate their cytotoxic activities. Four fractions (>30kDa, 10-30kDa, 3-10kDa and <3kDa) were evaluated for cytotoxic activity against a 4T1 cell line by MTT assay.
Findings: The MTT assay showed that although all fractions from the crab hydrolysate showed some activity, the low molecular weight samples (3-10kDa and <3kDa) were more effective than high molecular weight fractions (>30kDa and 10-30kDa) while the 3-10kDa fraction proved to be the most effective. The low molecular weight fractions significantly reduced the viability of the 4T1 cell lines in a dose-dependent manner upon 24 and 48h. The results were recorded in IC50 values of about 0.40±0.063mg mL-1 for <3 and 0.25±0.026mg mL-1 for 3-10kDa fractions.
Conclusion: Peptide fractions were isolated from the protein hydrolysate of the rocky shore crab Grapsus albolineatus are able to inhibit cancer cells and can be considered as a novel agent in nutraceutical and pharmaceutical ingredient applications.
B. Rasti, S.sh. shahangian,
Volume 10, Issue 1 (Winter 2019)
Abstract
Aims: Targeting DNA lies at the heart of anti-cancer therapies. Hence, DNA-binding drugs and their interaction with DNA have recently drawn the attention of researchers. Since DNA minor groove binders (MGBs) act as potent anti-tumor agents, there is a need to have detailed insights on how they interact with DNA. The mechanism of action of the majority of MGBs is not well studied at the molecular level.
Materials and Methods: Herein, molecular docking and dynamics simulations were performed, using AutoDock Vina and NAMD softwares, respectively, to evaluate the binding of A derivatives (Tallimustine, PNU 151807, and ) to , and to compare their interaction energy and binding patterns.
Findings: All three drugs were stably bound throughout the simulation, causing only minor modifications to the structure of DNA. Results of interaction energy analyses together with LigPlot outcomes showed that A/T residues are responsible for making the majority of non-bonding interactions in the case of all three drugs, showing a good agreement with previously reported findings on MGBs.
Conclusion: A/T residues are responsible for making the majority of non-bonding interactions in the case of all three drugs, showing a good agreement with previously reported findings on MGBs. Furthermore, our studies have shown that to the other members of the Distamycin A family, makes stronger interactions with , making it a better candidate for cancer therapy goals.
M. Afsharnezhad , S.s. shahangian , M. Salehi , R. Sariri,
Volume 10, Issue 4 (Fall 2019)
Abstract
The use of enzymes in organic solvents represents an important area of industrial and biotechnological development. However, organic solvents often cause protein denaturation, thereby reducing the activity and stability of enzymes. Use of stabilizing additives, protein engineering and chemical modification of enzymes are common strategies to overcome this problem. In this study, a cysteine protease from the latex of Ficus johannis was purified and the activity and stability of the protease were investigated in the presence of different organic solvents. The effect of trehalose, sorbitol, and sucrose on the enzyme activity was also studied in the presence of organic solvents. The results showed that the enzyme activity was elevated in the presence of low concentrations of organic solvents increased, while it was decreased with increasing concentration of organic solvents. However, the enzyme still retained 60% of its activity at 30% organic solvent concentration. The enzyme was considerably stable in the presence of organic solvents, maintaining almost 90% of its stability in the presence of 50% of all solvents. As stabilizing additives, sugars enhanced the catalytic activity and stability of the enzyme, and trehalose was the most effective sugar. The easy purification procedure and considerable activity and stability of the protease in the presence of organic solvents could suggest this enzyme as a good candidate for peptide synthesis industry.
Salim Alhafyan, Zeynab Rezaei, S.s. shahangian, Reza H. Sajedi,
Volume 14, Issue 2 (5-2023)
Abstract
Angiogenesis is involved in many physiological and pathological processes, including tumor growth, and VEGF is considered as the most important factor in this process. Nowadays, the production of single-domain antibodies (VHH) with the characteristic of inhibiting growth factors in cancer tumors is one of the new strategies for cancer treatment. In the previous research, it was found that camel VHHs isolated from phage display against VEGF play an essential role in inhibiting it. Here, the VHH that had the highest affinity for the VEGF was selected. Ice nucleation protein (INP) was used as anchoring motif for surface expression of E. coli, owing to the efficiency of its N terminal domain, this system is used to express the VHH. Accordingly, a construct harboring the first 537 nucleotide of InaK gene and nucleotide fragments of TEV protease recognition site and VEvhh10 was designed to express this protein in the surface display of E. coli cells. The results showed that the INP anchor is a suitable candidate for promoting the surface expression of VEvhh10 in E. coli. After expression of VEvhh10, isolation and purification were performed using centrifugation and washing, and its binding to VEGF was investigated. The results showed that VEvhh10 successful bind to VEGF and it can be used for therapeutic applications and clinical diagnosis of patients in the future.
Ali Foroutan Kalourazi, S.shirin shahangian,
Volume 15, Issue 4 (10-2024)
Abstract
Researchers are currently directing their efforts toward developing new enzyme stabilization and enhancement strategies to broaden their application in various industries. This study utilized a unified platform to stabilize and safeguard proteins in industrial settings. Despite the wide-ranging industrial applications of lipases, their utility in industrial processes is limited by their susceptibility to degradation under harsh environmental conditions. In our study, we used a dual-purpose strategy that involved both enzyme stabilization and the shielding of an organosilica protective layer. After expressing and purifying the recombinant lipase enzyme, we immobilized it onto silica nanoparticles and shielded it with an organosilica nanolayer to protect the enzyme. We meticulously examined the optimal thickness of the protective layer and its influence on enzyme stabilization against environmental stressors. Our research findings demonstrate that the immobilized enzyme exhibited a remarkable level of stability compared to its free enzyme when subjected to various factors, such as fluctuations in temperature and exposure to chemical agents. Furthermore, the immobilized samples displayed optimal activity across a broad range of temperatures, highlighting this approach's adaptability and efficacy. Notably, the organosilica layer significantly bolstered the reactivity recovery of denatured proteins with SDS and urea, highlighting the versatile applications of this method. These findings indicated that our present platform has great potential to improve the efficiency and stability of industrial enzymes against various environmental challenges.
