Computational studies and synthesis of 131iodine-labeled nocardiotide A analogs as a peptide-based theragnostic radiopharmaceutical ligand for cancer targeting SSTR2.

Radiolabeled peptides belong to a highly specific group of radiotracers used in oncology, particularly for diagnostics and cancer therapy. With the notable advantages of high binding affinity and selectivity to cancer cells, they have proven to be very useful in nuclear medicine. As a result, efforts have been focused on discovering new peptide sequences for radiopeptide preparation. Nocardiotide A, a cyclic hexapeptide comprising the amino acids cyclo-Trp-Ile-Trp-Leu-Val-Ala (cWIWLVA) isolated from Nocardiopsis sp., has shown significant cytotoxicity against cancer cells, rendering it a suitable candidate for the process. Therefore, the present study aimed to design a stable and effective radiopeptide by labeling nocardiotide A with iodine-131 (131I), ensuring that its affinity to SSTR2 is not compromised. In silico study showed that structural modification of nocardiotide A labeled with 131iodine exhibited good affinity value, forming hydrogen bonds with key residues, such as Q.102 and T.194, which are essential in SSTR2. Based on the results, cyclic hexapeptides of cWIWLYA were selected for further synthesis, and its peptide product was confirmed by the presence of an ionic molecule peak m/z [M + Na]+ 855.4332 (yield, 25.60%). In vitro tests conducted on cWIWLYA showed that cWIWLYA can bind to HeLa cancer cells. Radiopeptide synthesis was initiated with radiolabeling of cWIWLYA by 131I using the chloramine-T method that showed a radiochemical yield of 93.37%. Non-radioactive iodine labeling reaction showed that iodination was successful, which detected the presence of di-iodinated peptide (I2-cWIWLYA) with m/z [M + Na]+ 1107.1138. In summary, a radiopeptide derived from nocardiotide A showed great potential for further development as a diagnostic and therapeutic agent in cancer treatment.

In Vivo Pharmacodynamics of Calophyllum soulattri as Antiobesity with In Silico Molecular Docking and ADME/Pharmacokinetic Prediction Studies.

This study aims to determine the antiobesity activity of Calophyllum soulattri leaves extract (CSLE) on high fat diet-fed rats (HFD) and to predict the molecular docking and pharmacokinetics of selected compounds of Calophyllum soulattri to fat mass and obesity-associated protein (FTO). Daily body weight, organ, carcass fat (renal and anal), body mass index, total cholesterol, and total triglyceride levels were observed after CSLE was given orally for 50 days. Furthermore, body mass index of a CSLE dose of 50 mg/kgbw, 100 mg/kgbw and orlistat (120 mg/kgbw) group are 0.68, 0.57 and 0.52, respectively. The total body weight of the CLSE dose of 100 mg/kgbw group showed the lowest percentage change, followed by a CLSE dose of 50 mg/kgbw compared to the normal and positive control group. The carcass fat index of CSLE dose of 100 mg/kgbw was not significantly different from orlistat, which was in line with its total cholesterol level and triglyceride (p < 0.05). The binding affinity of selected compounds from Calophyllum soulattri (friedelin, caloxanthone B, macluraxanthone, stigmasterol, trapezifolixanthone, dombakinaxanthone, and brasixanthone B) to FTO are -8.27, -9.74, -8.48, -9.34, -8.85, -8.68 and -9.39 kcal/mol, which are better than that of orlistat at -4.80 kcal/mol. The molecular dynamics simulation showed that the interaction between Caloxanthone B compounds and obesity receptors was relatively stable. Lipinski's rule determined the absorption percentage of all compounds above 90% with good drug-likeness. The results showed the potential of CSLE as an antiobesity drug candidate.

Molecular Dynamics of Cobalt Protoporphyrin Antagonism of the Cancer Suppressor REV-ERBß.

Nuclear receptor REV-ERBß is an overexpressed oncoprotein that has been used as a target for cancer treatment. The metal-complex nature of its ligand, iron protoporphyrin IX (Heme), enables the REV-ERBß to be used for multiple therapeutic modalities as a photonuclease, a photosensitizer, or a fluorescence imaging agent. The replacement of iron with cobalt as the metal center of protoporphyrin IX changes the ligand from an agonist to an antagonist of REV-ERBß. The mechanism behind that phenomenon is still unclear, despite the availability of crystal structures of REV-ERBß in complex with Heme and cobalt protoporphyrin IX (CoPP). This study used molecular dynamic simulations to compare the effects of REV-ERBß binding to Heme and CoPP, respectively. The initial poses of Heme and CoPP in complex with agonist and antagonist forms of REV-ERBß were predicted using molecular docking. The binding energies of each ligand were calculated using the MM/PBSA method. The computed binding affinity of Heme to REV-ERBß was stronger than that of CoPP, in agreement with experimental results. CoPP altered the conformation of the ligand-binding site of REV-ERBß, disrupting the binding site for nuclear receptor corepressor, which is required for REV-ERBß to regulate the transcription of downstream target genes. Those results suggest that a subtle change in the metal center of porphyrin can change the behavior of porphyrin in cancer cell signaling. Therefore, modification of porphyrin-based agents for cancer therapy should be conducted carefully to avoid triggering unfavorable effects.

Determination of Anthraquinone in Some Indonesian Black Tea and Its Predicted Risk Characterization.

Anthraquinone (AQ) levels in some Indonesian dried tea leaves samples from different plantation areas and their brewed tea samples were determined by gas chromatography-tandem mass spectrometry methods. The mean lower bound, middle bound, and upper bound of AQ levels in 59 dried tea leaves samples were 82.2, 82.8, and 83.4 µg/kg, respectively, while their 95%th percentile values were identical at 190.3 µg/kg (0.1903 mg/kg). In a transfer rate study, the mean and 95%th AQ levels in 30 dried tea leaves samples with AQ level ≥ LOQ (limit of quantification) were 128.6 and 194.5 µg/kg (0.1945 mg/kg), while those of their corresponding brewed tea samples were 2.1 and 3.4 µg/kg, respectively. The mean and 95%th transfer rates of AQ into brewed tea samples were 51.99 and 88.17%. Using these data and taking into account daily tea consumption, calculated cancer potency slope factor, benchmark dose of 10% effect at lower bound 95% confidence interval of AQ, and average body weight, the risk characterization due to exposure to this compound from tea consumption was calculated and stated as incremental lifetime cancer risk (ILCR) and margin of exposure (MOE). The overall results revealed that AQ levels in dried tea leaves up to the highest level found in the samples lead to an ILCR of not more than 10-6 and an MOE of not less than 104 and hence was predicted to give sufficient consumer protection.

Computational Study of Imidazolylporphyrin Derivatives as a Radiopharmaceutical Ligand for Melanoma.

BACKGROUND: Melanoma is the most aggressive type of skin cancer. Metastatic melanoma is extremely difficult to treat with current therapy methods such as surgery. On the other hand, it is a good opportunity to develop a radiopharmaceutical using a radionuclide such as Technetium (Tc) for diagnostic and Rhenium (Re) for therapeutic purposes. T3,4BCPP has been be used as a radioimaging agent for melanoma cancers experimentally. The aim of the present research was to design new imidazolylporphyrin derivatives with better selectivity and higher affinity than those of T3,4BCPP by molecular modeling. METHODS: Eight types of Re- and Tc-labeled imidazolylporphyrins were docked to Fibroblast Growth Factor Receptor 1 (FGFR1, PDB ID: 5AM6) using AutoDock 4.2. FGFR1 was simulated by Molecular Dynamic (MD) simulation for 30 ns using NAMD 2.10 at 37 °C. The obtained conformations were then applied in a molecular docking simulation. Dovitinib (natural ligand of FGFR1), Re- and Tc-T3, 4BCPP were used as references. RESULTS: The MD simulation resulted in an RMSD of 3.8 Å. From all the studied imidazolylporphyrin derivatives, Tc-cD3, 4BCPMIP and Re-cD3, 4BCPIP had the best docking parameter. Tc-cD3, 4BCPMIP had a free binding energy of -4.06 kcal/mol, while that of Re-cD3, 4BCPIP was -4.35 kcal/mol. CONCLUSION: It is concluded that cD3,4BCPMIP and cD3,4BCPIP are two potential candidate ligands for a melanoma radiopharmaceutical kit.

In Silico Study, Synthesis, and Cytotoxic Activities of Porphyrin Derivatives.

Five known porphyrins, 5,10,15,20-tetrakis(p-tolyl)porphyrin (TTP), 5,10,15,20-tetrakis(p-bromophenyl)porphyrin (TBrPP), 5,10,15,20-tetrakis(p-aminophenyl)porphyrin (TAPP), 5,10,15-tris(tolyl)-20-mono(p-nitrophenyl)porphyrin (TrTMNP), 5,10,15-tris(tolyl)-20-mono(p-aminophenyl)porphyrin (TrTMAP), and three novel porphyrin derivatives, 5,15-di-[bis(3,4-ethylcarboxymethylenoxy)phenyl]-10,20-di(p-tolyl)porphyrin (DBECPDTP), 5,10-di-[bis(3,4-ethylcarboxymethylenoxy)phenyl]-15,20-di-(methylpyrazole-4-yl)porphyrin (cDBECPDPzP), 5,15-di-[bis(3,4-ethylcarboxymethylenoxy)phenyl]-10,20-di-(methylpyrazole-4-yl)porphyrin (DBECPDPzP), were used to study their interaction with protein targets (in silico study), and were synthesized. Their cytotoxic activities against cancer cell lines were tested using 3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazolium bromide (MTT) assay. The interaction of porphyrin derivatives with carbonic anhydrase IX (CAIX) and REV-ERBß proteins were studied by molecular docking and molecular dynamic simulation. In silico study results reveal that DBECPDPzP and TrTMNP showed the highest binding interaction with REV- ERBß and CAIX, respectively, and both complexes of DBECPDPzP-REV-ERBß and TrTMNP-CAIX showed good and comparable stability during molecular dynamic simulation. The studied porphyrins have selective growth inhibition activities against tested cancer cells and are categorized as marginally active compounds based on their IC50.