Molecular docking analysis of protein filamin-A with thioazo compounds

It is of interest to document the molecular docking analysis of protein Filamin-A with thioazo compounds. The compounds 1, 3, 5, and 6 showed best molecular docking interaction as compared to the drug doxorubicin. Among the selected ligands (1-6), compound 3 shows better interaction score than doxorubicin and follows Lipinski's rule of five. Hence, it could be considered as a potential lead molecule for inhibiting protein filamin A in the treatment of oral cancer.


Background:
Protein filamin A is commonly expressed in oral Cancer.Due to its dual mechanism, it promotes cancer if present in cytoplasm and suppresses the tumor if present in plasma membrane.Development of drugs to target FLN-A cause cleavage and subsequent localization to the nucleus, this could be a new and potent field of research in treating cancer.Protein FilaminA is the first actin filament cross linking protein or gelation factor to be found in nonmuscle cells for more than 90 binding proteins (Fln b and c) the products of separate genes list the partners implicated in cell adhesion and migration.The other partners are human FLN gene mutations induce a wide variety of cell and tissue abnormalities due to the extensive array of related proteins [1].The role of FLNa in cell migration and adhesion are the main topics.Two 280kDa subunits make up FLNa which self assembles into a 160 nm semi flexible stand.Each FLN subunit has 24 repeating plated sheet units at the end of its N terminal spectrin related actin binding domain.

Materials and methods: Ligand preparation:
The 2D chemical structures of the thioazo compounds (1-6) were prepared using ChemOffice Suite 16.0 (Figure 1).During the optimization method, the software Chem3D was employed and all parameters were selected in order to achieve a stable structure with the least amount of energy.The structural optimization approach was used to estimate the global lowest energy of the title chemical.Each molecule's 3D coordinates (PDB) were determined using optimized structure.

Protein preparation:
The 3D structure of Protein Filamin A from Homo sapiens was retrieved from the protein data bank (PDB Id: 3HOP) and was prepared in accordance with standard protocol (Figure 2).Water molecules, other hetero atoms, co-crystallized ligands were removed, and the protein were prepared by adding polar hydrogens and kollman charges with Auto Prep.

Molecular docking:
The graphical user interface Auto Dock vina was used for Ligand-Protein docking interactions (Figure 3 and 4).Auto Dock Tools (ADT), a free visual user interface (GUI) for the AutoDock Vina software, was used for the molecular docking research.In order to dock the compounds (1-6) against the protein's active site, AutoDockVina was employed with a grid point center spacing of 34.423, -24.624, -32.632 along the x, y, z axis respectively.The dimensions (Angstrom) of the grid box are 17.959, 15.780, and 16.467 that point in the x, y, and z directions, respectively.For each ligand, nine alternative conformations were created and ranked based on their binding energies using the AutoDockVina scoring functions.The post-docking evaluations were conducted using PyMOL and AutoDock Tools.

ADMET Analysis:
The SwissADME and PRO-TOX II online servers were used for estimating the absorption, distribution, metabolism, and excretion and toxicity profiles.The SwissADME, a web tool from Swiss Institute of Bioinformatics (SIB) is used to convert the twodimensional structures into their simplified molecular input line entry system (SMILES).The physicochemical properties (molar refractivity, topological polar surface area, number of hydrogen bond donors/ acceptors); pharmacokinetics properties (GI absorption, BBB permeation, P-gp substrate, cytochrome-P enzyme inhibition, skin permeation (log Kp)) which are critical parameters for prediction of the absorption and distribution of drugs within the body, and drug likeness (Lipinski's rule of five) were predicted using SwissADME.The toxicological endpoints (Hepatotoxicity, Carcinogenicity, Immunotoxicity, and Mutagenicity) and the level of toxicity (LD50, mg/Kg) are determined using the ProTox-II server.

Statistical Analysis:
One way ANOVA was used for statistical analysis.The clinically proven drugs are used as a control and the results are compared.
The significance of the results was found to be p< 0.05

Results:
Molecular docking interaction of thioazo compounds against Protein Filamin A of Homo sapiens: All the compounds (1-6) are run against the target against Protein Filamin A of Homo sapiens and it shows the range between -4.8 to -6.6 (Table 1).The compounds 1, 3, 5, and 6 showed best docking interaction as compared to drug Doxorubicin (-5.5 kcal/mol).

Toxicity profiling:
The compounds 1, 2, and 5 shows class 3 toxicity but none of the molecules are cytotoxic.Compounds 3 and 4 shows a similar LD50 value (3000mg/kg) and class 5 toxicity.Also, they are inactive in hepatotoxicity, carcinogenicity, immunotoxicity, and cytotoxicity (Table 4).Hence, compounds 3, and 4 can be used as a potential lead.

Conclusion:
Data shows that compound #3 shows better interaction than doxorubicin and paclitaxel and follows Lipinski's rule of 5. Hence, it could be considered as a potential lead molecule for inhibiting protein Filamin A in the treatment of cancer.

Scope for future research:
The molecule has to be developed for future research.Compounds with functional groups similar to lead molecules have to be explored.
The repeats are divided into rod1(repeats 1-5) rod 2 (repeats 10-23) and self-association domain by two intervening Calpain sensitive hinges (IgFLN) each of which is made up of seven runs of (AG) strands 9, 10IgFLNa 24 the most C terminal repeat, mediates [2].The C terminal repeat IgFLNa24 facilitates dimerization and gives dimeric molecules a V shape which causes F actin to branch perpendicularly.The F actin binding domain Rod2 on the other hand associates with partner proteins and most partner interactions occur within the rod 2 domain [3].Binding and positioning of multiple partners in close proximities on rod 2 facilitates signal transduction of FLNa enriched sites in cell.The most prevalent and extensively distributed number of filamin proteins is FLNa which is encoded on the X chromosomes.On human chromosome 3, FLNb a non-muscle is encoded [4].The FLN gene is found in chromosome 7 and is mostly expressed in smooth, striated similarities and differences between 56, 57 FLN isoform structures, expression levels and localization characteristics [5].Therefore, it is of interest to document the molecular docking analysis of protein Filamin-A with thioazo compounds.

Figure 2 :
Figure 2: 3D structure of the protein Filamin A from Homo sapiens

Figure 3 :
Figure 3: Molecular docking analysis of compounds (1-3) against Protein filamin A of Homo sapiens

Figure 4 :
Figure 4: Molecular docking analysis of compounds (4-6) against Protein filamin A of Homo sapiens

Table 4 :
(1)(2)(3)(4)(5)(6)f selected thioazo compounds(1)(2)(3)(4)(5)(6)Mouth and throat cancers are included in the category of oral cancer.On the tongue, the skin lining the mouth and gums, beneath the tongue, at the base of the tongue, and in the region of the throat towards the rear of the mouth, oral malignancies can grow [6].
[13]uding increased drug half-life, decreased toxicity, and targeted and selective delivery[13].Nanodrugs can accumulate in tissue, which may be related to increased permeability and retention as well