Carbonic Anhydrase Research Articles

Inhibition Effects of Some Non-Proteinogenic Amino Acid Derivatives on Carbonic Anhydrase Isoenzymes and Acetylcholinesterase: An In Vitro Inhibition and Molecular Modeling Studies.

Amino acid derivatives are molecules of interest for medicinal chemistry and drug design studies due to their important chemical properties. In this study, the inhibition effects of some non-proteinogenic amino acid derivatives (hippuric acid (A), N-(9-Fluorenylmethoxycarbonyl)-D-valine (B), N-Z-(1-Benzotriazolylcarbonyl) methylamine (C), (S)-N-Z-1-Benzotriazolylcarbonyl-2-phenylethylamine (D)) on carbonic anhydrase I (hCA-I), II (hCA-II) isoenzymes and acetylcholinesterase (AChE) activity, whose inhibitors are of vital pharmacological importance, were examined. While carbonic anhydrase (CA) inhibitors are effective molecule candidates for the treatment of many diseases from glaucoma to cancer, acetylcholinesterase inhibitors are target molecules for the treatment of Alzheimer's disease. According to the results of this study, compound D had a strong inhibitory effect on hCA-I (IC50: 0.836 μM) and hCA-II (IC50: 0.661 μM), while compound B (IC50: 100 μM) showed a strong inhibitory effect on AChE activity. In addition, inhibition results were supported by molecular modeling studies. We hope that the obtained results will contribute to the synthesis of new and effective amino acid derivative inhibitors for CA and AChE.

New Sulfonate Ester-Linked Fluorinated Hydrazone Derivatives as Multitarget Carbonic Anhydrase and Cholinesterase Inhibitors: Design, Synthesis, Biological Evaluation, Molecular Docking and ADME Analysis.

In this study, some new hydrazone derivatives (2a-g) was designed, synthesized for first time, and evaluated as multitarget inhibitors of AChE, BChE, hCA I and hCA II. The chemical structures of new hybrids were confirmed by elemental analysis and some spectroscopic techniques. All tested compounds showed low nanomolar inhibition with IC50 values of in the range of 30.4-264.0 nM against hCA I, 23.2-251.6 nM against hCA II, 12.1-114.3 nM against AChE, and 76.4-134.0 nM against BChE. These compounds inhibited hCA I and AChE more than acetazolamide (AZA) and neostigmine. Among them, compounds 2c and 2e, which have a linear structure, were determined to be the most active inhibitor candidates against these selected enzymes. Molecular docking studies were carried out on the compounds (2a--g), revealing their binding interactions with the active site of AChE, BChE, hCA I and hCA II thus supporting the experimental findings. Additionally, in silico absorption, distribution, metabolism, and excretion (ADME) prediction studies of the obtained compounds (2a--g) with in silico approaches were carried out to determine their solubility, whether they have the potential to cross the blood-brain barrier (BBB), values such as GI absorption and drug likeness principles.

Gene expression microarray analysis during metamorphosis and early calcification in the scleractinian coral Acropora millepora

ABSTRACT In the face of global warming and ocean acidification, understanding the cellular mechanisms underlying coral metamorphosis and early calcification is essential, as both processes are likely to be affected by a changing environment. In this study, we used cDNA microarray expression analysis to compare transcription profiles between four distinct life stages in the ‘complexa’ coral Acropora millepora: 1) aposymbiotic non-calcifying planula, 2) aposymbiotic calcifying flat polyp, 3) aposymbiotic calcifying primary polyp and 4) symbiotic adult tip. Highly up-regulated genes in planulae were molecules involved in calcium signalling, lipid metabolism and development. Transcripts up-regulated in post-settlement juvenile stages regulate tissue morphogenesis, cell division and responses to oxidative stress. Transcripts with the highest expression in adult polyps are involved in responses to abiotic stimuli and asexual reproduction. Transcripts up-regulated in calcifying stages included carbonic anhydrases and organic matrix components. Additionally, our results suggest an overlap between intracellular secondary messengers following settlement and metamorphosis. A subset of fluorescent proteins were up-regulated at the planula stage but down-regulated after settlement, supporting the idea that these molecules might have a role in quenching reactive oxygen species. Altogether, our results suggest that Acropora developmental stages are transcriptionally distinct units in which transcription profiles reflect responses to different physiological and ecological conditions.

Uncovering the roles of the scaffolding protein CsoS2 in mediating the assembly and shape of the α-carboxysome shell.

Carboxysomes are a paradigm of organelle-like structures in cyanobacteria and many proteobacteria. These nanoscale compartments enclose Rubisco and carbonic anhydrase within an icosahedral virus-like shell to improve CO2 fixation, playing a vital role in the global carbon cycle. Understanding how the carboxysomes are formed is not only important for basic research studies but also holds promise for repurposing carboxysomes in bioengineering applications. In this study, we focuses on a specific scaffolding protein called CsoS2, which is involved in facilitating the assembly of α-type carboxysomes. By deciphering the functions of different parts of CsoS2, especially its middle region, we provide new insights into how CsoS2 drives the stepwise assembly of the carboxysome at the molecular level. This knowledge will guide the rational design and reprogramming of carboxysome nanostructures for many biotechnological applications.

Synthesis, computational analysis, and anti-proliferative evaluation of novel bithienylbenzamidine derivatives: Towards cytostatic cancer therapeutics

Our research unveils the synthesis and characterization of four novel monocationic 2,5-diarylbithiophene derivatives 4a-d, prepared through Suzuki cross-coupling reactions and subsequent amidine formation. Density Functional Theory (DFT) calculations provide unprecedented insights into the electronic properties and structure-activity relationships of these compounds. In vitro screening against the NCI-60 cancer cell panel demonstrates remarkable anti-proliferative activities. Compound 4c emerges as a standout candidate, exhibiting potent growth inhibition across multiple cancer types, with GI50 values as low as 0.36 µM against certain ovarian cancer lines. Intriguingly, our research suggests a potential shift from purely cytotoxic towards more cytostatic behavior, potentially offering improved therapeutic windows and reduced side effects. Molecular docking studies provide evidence for the compounds' interaction with human carbonic anhydrase IX, hinting at a possible mechanism of action. This comprehensive study not only introduces a promising new class of anti-cancer compounds but also provides a rich foundation of structural, electronic, and biological data to fuel future research. The bithienylbenzamidine derivatives, particularly compound 4c, represent exciting candidates for further development in the ongoing battle against cancer.

Two factors facilitate the cost-effective and harmless cementation of rare earth slags through MICP technology: Carbonic anhydrase bacteria and endogenous calcium ions

Microbially induced carbonate precipitation (MICP), a solidification/stabilization technique that doesn't interfere with recycling and can reduce the migration of pollutants, has been employed to cement rare earth slags (RES). Currently, the MICP process of the urease/carbonic anhydrase pathway has attracted considerable attention. However, the MICP process of the urease pathway may produce high concentrations of ammonia, which can cause secondary contamination; the addition of a calcium source (calcium chloride) may increase the cost of the treatment process. In this study, two factors, carbonic anhydrase bacteria and endogenous calcium ions (Ca²⁺), facilitated the MICP technology to cost-effectively and harmlessly cement RES and stabilize contaminants. The findings indicated that strain Z1 could utilize endogenous Ca²⁺ to cement the RES, thereby enhancing its unconfined compressive strength, reducing the disintegration rate, radiation dose, and wind erosion intensity, and facilitating the stabilization of heavy metals and radionuclides. In comparison to the CK group, the leaching concentrations of Cu2+, Pb2+, Zn2+, Cd2+, Th(Ⅳ), and U(Ⅵ) in the C1 group were reduced by 42.37 %, 20.20 %, 18.77 %, 22.53 %, 12.32 %, and 23.66 %, respectively. The treatment effect can be further enhanced by adding exogenous Ca2+. This study's findings can help reduce the potential environmental risks in the long-term sequestration of RES, while also providing technical support for the sustainable development of the rare earth industry.

Neuroprotective Potential of Ethoxzolamide Targeting Oxidative Stress and Inflammation in Experimental Models of Intracerebral Hemorrhage.

As antioxidant and anti-inflammatory agents, carbonic anhydrase inhibitors can exert potentially useful therapeutic effects following central nervous system trauma, including intracerebral hemorrhage (ICH). However, the therapeutic efficacy of ethoxyzolamide (ETZ) as a novel carbonic anhydrase inhibitor for ICH has not yet been determined. An autologous blood injection method was used to establish ICH models, which were then used to establish the effects of intraperitoneal injection of ETZ on ICH. Neuronal damage, apoptotic protein expression, oxidative and inflammatory factor content, microglia marker Iba-1 positivity, hepatic and renal pathological changes, and serum concentrations of hepatic and renal function indices were assessed by Nissl staining, western blotting, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, hematoxylin and eosin (HE) staining, and automatic biochemical analysis in brain tissues. The ICH group showed massive hemorrhagic foci; significant increases in brain water content, modified mouse neurological deficit scoring (mNSS) score, pro-apoptotic protein expression, oxidative factors, pro-inflammatory factors, and Iba-1 positivity; and significant reductions in Nissl body size, anti-apoptotic protein expression, and antioxidant factors, all of which were reversed by ETZ in a dose-dependent manner. ETZ has a good biosafety profile with no significant burden on the human liver or kidneys. The Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway was mildly activated in ICH mice, and was further increased after ETZ injection. Molecular docking experiments revealed that ETZ could dock onto the Nrf2-binding domain of keap1. ETZ, as a novel carbonic anhydrase inhibitor, further activated the Keap1/Nrf2 pathway by docking with the Nrf2-binding domain of keap1, thereby exerting antioxidant, anti-inflammatory, anti-apoptotic, and cerebral neuroprotective effects in ICH mice.

Preyssler heteropolyacid-mediated direct deprotection/N-benzoylation of N-Boc-protected sulfonamides: synthesis, molecular docking, DFT study and in-silico ADME evaluation of novel benzamides bearing the sulfonamide moiety as possible inhibitors of human carbonic anhydrase II

An adequate method is described for the synthesis of new substituted benzamides containing a sulfonamide moiety using Preyssler heteropolyacid H14[NaP5W30O110] as an efficient catalyst. This method proceeds in one-step, including deprotection and benzoylation of N-(tert-butoxycarbonyl) sulfonamides to give the target compounds good yields (up to 92%). A molecular docking was performed to study the interactions between the synthesized benzamides and human carbonic anhydrases II. It was concluded that all compounds demonstrated good binding score values (up to −9.4 kcal/mol) for the active site of all selected proteins when compared with the reference drug Acetazolamide (−6.3 kcal/mol). In addition, the ADME/T analyses show that all synthesized molecules exhibited good pharmacokinetics and bioavailability. The theoretical calculations for all compounds were performed using the DFT/B3LYP/6–31G (d,p) level of theory. The study yielded optimized structural parameters, global reactivity descriptors, and Frontier Molecular Orbitals (FMO’s).

Novel three-stage microalgal cultivation system for lipid production utilizing nutrients derived from refinery waste

The pollution and transformation of refineries are receiving increasing attention. The carbonic anhydrase in Tetradesmus obliquus was found exhibiting a hysteresis phenomenon in response to periodic changes in the composition of external carbon sources, with a surge in inorganic carbon concentration stressing the carbonic anhydrase activity to increase by 6–9 times. On this basis, a novel three-stage culture system of T. obliquus was proposed, which mainly uses refinery waste as the nutrients. By controlling the nutrient content in the environment, especially the composition of carbon sources, microalgae could sequentially complete rapid biomass accumulation, efficient inorganic carbon assimilation, and oil production. Compared to a single-environment culture system, the biomass yield increased by 1.34 times, the oil content increased by more than 6%, and the oil productivity increased by 2.08 times. Above findings may lay a partial theoretical foundation for the future evolution of traditional refineries towards “fossil–algal-biomass” hybrid refineries.

Benzimidazolium salts bearing ester group: Synthesis, characterization, crystal structure, molecular docking studies, and inhibitory properties against metabolic enzymes

In this work, the synthesis of several unsymmetrical benzimidazolium salts with an ester (2-ethoxy-2-oxoethyl) group on the nitrogen atom is described. The structures of all compounds were fully characterized by spectroscopic (1H, 13C NMR, FTIR) and analytical (elemental analysis) methods. However, single-crystal X-ray diffraction analysis elucidated the molecular and crystal structures of compounds 1a and 1c. Asymmetric units of both crystal structures contain two crystallographically independent molecules and two bromide anions. All compounds exhibited substantial inhibition against the cytosolic carbonic anhydrase isoforms (hCA I and hCA II) and acetylcholinesterase (AChE) with Ki values 51.00–45.18 nM, 46.94–305.65 nM, and 17.57–65.68 nM, respectively. Notably, compound 1d showed extreme inhibitory effect against hCA I with 51.00±5.31 nM (AZA: 275.44±13.32 nM), hCA II with 46.94±5.44 nM (AZA: 236.55±17.88 nM) and AChE with 17.57±3.14 nM (TAC: 80.44±6.88 nM). In silico approach showed that compound 1d could form stable complexes with target enzymes with a different binding affinity (BE:9.01 kcal/mol for AChE; -7.22 kcal/mol for hCA II and -6.51 kcal/mol for hCA I). The results supported the medical potential of benzimidazolium salts containing ester group. They significantly lighted our knowledge about the chemistry of side groups on phenyl ring especially in the para position as compared to ortho and meta positions.

Experimental Spectroscopic and Computational Studies on A New Synthesized Sulfisoxazole Derivative; Molecular Docking, Drug-likeness, ADME, Toxicity Predictions and Carbonic Anhydrase II Activity Investigations

In this paper, 5-Dimethylamino-2-hydroxy-3-methoxy benzaldehyde sulfisoxazole (5DHMS) and Cu(5DHMS)2 compounds have been synthesized. The molecular structure characterizations were performed using experimental and computational methods. In the experimental part of the study, CHNS, FT-IR, NMR, TGA, and LC-MS analysis techniques were used. In the theoretical part, Density Functional Theory (DFT) was selected for the calculation level. Firstly, optimized structures were obtained from the predicted 3D structures. Vibrational modes were calculated using the optimized structures of the compounds. The vibrational modes of each compound were analyzed in detail using potential energy distribution (PED). Molecular electrostatic potential and HOMO-LUMO maps were drawn. Global chemical reactivity descriptors of compounds were determined. Moreover, the solvent media effects on chemical reactivity descriptors were revealed in detail. Protein-ligand interactions with the target receptor carbonic anhydrase II enzyme were performed. In addition, some important biological activity parameters such as drug-likeness, toxicity, and ADME predictions were examined in silico.

Isolation and Whole-genome analysis of Desmodesmus sp. SZ-1: Novel acid-tolerant carbon-fixing microalga

Utilizing microalgae to capture flue gas pollutants is an effective strategy for mitigating greenhouse gas emissions. However, existing carbon-fixing microalgae exhibit poor tolerance towards acidic flue gas. In this study, the Desmodesmus sp. SZ-1, which can thrive in acidic environments and efficiently sequester CO2, was isolated. Desmodesmus sp. SZ-1 exhibited strong acid tolerance ability, with an average carbon fixation rate of 497.6 mg/L/d under 10 % CO2 and pH 3.5. Physiological analysis revealed that SZ-1 responded to high CO2 by increasing chlorophyll levels while coping with acidic stress by activating antioxidant enzymes. Genome analysis revealed a large number of carbon fixation and acid adaptation genes, involved in membrane lipid biosynthesis, H+ pumps, molecular chaperones, peroxidase system, amino acid synthesis, and carbonic anhydrase. This study provides a novel algal resource for mitigating acid gas emissions and a comprehensive genetic database for genetically modifying microalgae.

Benzoxaborinine, New Chemotype for Carbonic Anhydrase Inhibition: Ex Novo Synthesis, Crystallography, In Silico Studies, and Anti-Melanoma Cell Line Activity.

The benzoxaborinine scaffold, a homologue of benzoxaborole with an additional carbon atom in the boracycle, shows significant potential in developing new therapeutic agents. This study reports the synthesis, inhibition assays against four human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms, and anti-melanoma evaluation of 7-aryl(thio)ureido-substituted benzoxaborinines. Some derivatives, particularly compound 11, exhibited potent inhibitory activity (below 65 nM) against hCA IX and XII and stronger antiproliferative effects than SLC-0111 on human melanoma cells under hypoxia. Crystallographic studies of benzoxaborinine 3 adducts with hCA I and II demonstrated the binding mode of this chemotype, revealing that although both benzoxaborinine 3 and benzoxaborole 10 share a similar zinc-binding mode, the expanded ring in benzoxaborinine led to a different orientation within the active site. These findings suggest that benzoxaborinines hold promise for designing novel carbonic anhydrase inhibitors.

A robust synthetic biology toolkit to advance carboxysome study and redesign.

Carboxysomes are polyhedral protein organelles that microorganisms use to facilitate carbon dioxide assimilation. They are composed of a modular protein shell which envelops an enzymatic core mainly comprised of physically coupled Rubisco and carbonic anhydrase. While the modular construction principles of carboxysomes make them attractive targets as customizable metabolic platforms, their size and complexity can be a hinderance. In this work, we design and validate a plasmid set - the pXpressome toolkit -in which α-carboxysomes are robustly expressed and remain intact and functional after purification. We tested this toolkit by introducing mutations which influence carboxysome structure and performance. We find that deletion of vertex-capping genes results in formation of larger carboxysomes while deletion of facet forming genes produces smaller particles, suggesting that adjusting the ratio of these proteins can rationally affect morphology. Through a series of fluorescently labeled constructs, we observe this toolkit leads to more uniform expression and better cell health than previously published carboxysome expression systems. Overall, the pXpressome toolkit facilitates the study and redesign of carboxysomes with robust performance and improved phenotype uniformity. The pXpressome toolkit will support efforts to remodel carboxysomes for enhanced carbon fixation or serve as a platform for other nanoencapsulation goals.

Association between the use of prostaglandin analogues and ocular surface disease: a systematic review.

Patients with glaucoma often experience chronic ocular surface diseases, potentially underestimated in frequency and severity. To provide updated estimates of ocular surface diseases linked to prostaglandin analogue antiglaucoma eye medication, a systematic review was conducted. Twenty-seven publications were selected from databases like PubMed, Scopus, and Web of Science, following a search strategy targeting glaucoma and prostaglandins while excluding certain medications '(Glaucoma AND prostaglandins OR 'prostaglandin analogues')('eye drops' OR 'artificial tears' OR 'ocular surface' OR 'dry eye' OR 'dry eye syndrome' OR 'ocular surface disease' OR 'tear film') NOT ('beta blockers' OR 'alpha adrenergic agonists' OR 'carbonic anhydrase inhibitors' OR 'rho-quinase')'. The review revealed a correlation between prostaglandin analogue use and ocular surface damage, assessing parameters such as tear break-up time, Schirmer test value, ocular surface staining, hyperaemia score, and meibomian gland characteristics. Some studies explored switching patients to alternative glaucoma medications, noting varied effects on ocular surface parameters. Comparisons suggested better tolerance and outcomes with preservative-free options over prostaglandins. Additionally, the impact of treatment duration and diquafosol on ocular health, including meibomian gland loss, was examined across different formulations. Although a link between prostaglandin analogues (with or without preservatives) and ocular surface damage was established, inconsistencies in methodologies and assessment across studies were noted. This comprehensive review, spanning a decade of glaucoma research, underscores the need for re-evaluation of treatment strategies in ophthalmology. It stresses the significance of informed decision-making for enhanced glaucoma care, taking into account the observed effects of various medications on eye health.

Overexpressing Carbonic Anhydrase Transgenic Rice Plants Maintain the Regular Soil Functions and Microbial Activities of Soil

Background: Genetically modified (GM) crops are focused on establishing desirable traits to support the food demand of increasing populations. The effect of transgenic plants on soil diversity has been highlighted by a lot of researchers. Some of them showed the negative effect of transgenic crop on soil microbes and the food chain. So there is an urgent need to develop transgenic plants with no harmful effects on environmental health. Methods: We have examined the effects salt tolerant carbonic anhydrase overexpressing transgenic rice plants on the physiology of rhizospheric microbes and their enzymatic activities. In the present study, we have used pot experiments in the greenhouse of Centurion University of Technology and management, Bhubaneswar, Odisha, India. Result: No significant variation in the soil properties viz., pH, Eh, organic C, P, K, N, Ca, Mg, S, Na and Fe+2 were observed. The population of bacteria, fungi and nematodes were remained same in the soil. The enzymatic activities like soil dehydrogenase, nitrate reductase, urease and alkaline phosphatase were not significantly affected. Further, plant growth promotion (PGP) functions such as HCN, siderophore, salicylic acid, GA, IAA, zeatin, were, not influenced considerably. The present study ecologically pertinent of salt tolerant CA transgenic rice to usual functions of the rhizospheric organisms.

Integrated approach of machine learning, Mendelian randomization and experimental validation for biomarker discovery in diabetic nephropathy.

To identify potential biomarkers and explore the mechanisms underlying diabetic nephropathy (DN) by integrating machine learning, Mendelian randomization (MR) and experimental validation. Microarray and RNA-sequencing datasets (GSE47184, GSE96804, GSE104948, GSE104954, GSE142025 and GSE175759) were obtained from the Gene Expression Omnibus database. Differential expression analysis identified the differentially expressed genes (DEGs) between patients with DN and controls. Diverse machine learning algorithms, including least absolute shrinkage and selection operator, support vector machine-recursive feature elimination, and random forest, were used to enhance gene selection accuracy and predictive power. We integrated summary-level data from genome-wide association studies on DN with expression quantitative trait loci data to identify genes with potential causal relationships to DN. The predictive performance of the biomarker gene was validated using receiver operating characteristic (ROC) curves. Gene set enrichment and correlation analyses were conducted to investigate potential mechanisms. Finally, the biomarker gene was validated using quantitative real-time polymerase chain reaction in clinical samples from patients with DN and controls. Based on identified 314 DEGs, seven characteristic genes with high predictive performance were identified using three integrated machine learning algorithms. MR analysis revealed 219 genes with significant causal effects on DN, ultimately identifying one co-expressed gene, carbonic anhydrase II (CA2), as a key biomarker for DN. The ROC curves demonstrated the excellent predictive performance of CA2, with area under the curve values consistently above 0.878 across all datasets. Additionally, our analysis indicated a significant association between CA2 and infiltrating immune cells in DN, providing potential mechanistic insights. This biomarker was validated using clinical samples, confirming the reliability of our findings in clinical practice. By integrating machine learning, MR and experimental validation, we successfully identified and validated CA2 as a promising biomarker for DN with excellent predictive performance. The biomarker may play a role in the pathogenesis and progression of DN via immune-related pathways. These findings provide important insights into the molecular mechanisms underlying DN and may inform the development of personalized treatment strategies for this disease.

6477 Surprise Finding For A Thyroid Nodule: Metastatic Renal Cell Carcinoma

Abstract Disclosure: A. Xu: None. E. Hsu: None. Introduction: A patient with an incidental and asymptomatic thyroid nodule underwent fine needle aspiration biopsy (FNA) after the nodule increased in size. Without a definite pathology after three FNA attempts, thyroidectomy was performed, where pathology found metastatic renal cell carcinoma (RCC). Clinical Case: A 64 year old woman had a past medical history of obesity, type 2 diabetes, RCC (stage I: pT1bN0M0) treated with right radical nephrectomy five years prior and thought to be in remission, remote smoking history smoking, and coronary artery disease with coronary artery bypass graft (CABG) two months prior, on anticoagulation. The patient reported a distant history of right thyroid lobectomy over a decade prior for unclear reasons, but she was adamant that the pathology was benign. Two years prior to presentation, CT chest done for RCC surveillance had detected a left thyroid nodule. Ultrasound at the time revealed a 3.6 x 1.9 x 2.3 cm solid, isoechoic nodule in the upper left lobe, which was not taller than wide, and had smooth margins and no echogenic foci. A repeat ultrasound at the time of presentation showed interval growth of the nodule, now measuring 4.3 x 2.1 x 2.9 cm. FNA was unsatisfactory, yielding predominantly blood. Patient felt well and had no compressive neck symptoms. We opted to wait two months and repeat FNA, which resulted as atypia of undetermined significance - Bethesda category III (AUS). We recommended completion thyroidectomy, but patient preferred to avoid surgery. We decided to wait two months and repeat FNA with molecular testing. This third FNA resulted AUS again; however, due to non-medical reasons, molecular testing was not performed. Another ultrasound showed slight growth of the nodule, 5.1 x 2.9 x 2.0 cm, which appeared hypoechoic now, but was still not taller than wide, with smooth margins and no echogenic foci. Completion thyroidectomy was performed, with pathology showing metastatic clear cell renal cell carcinoma. Immunostains were positive for carbonic anhydrase and renal cell carcinoma marker and negative for TTF-1. Whole-body PET-CT showed no hypermetabolic foci, and a repeat PET-CT one year later still showed no evidence of metastatic disease. Other than a hospitalization for COVID-19, patient is doing well and asymptomatic now over a year after her thyroidectomy. Oncology will continue routine surveillance imaging for her metastatic renal cell carcinoma thought to be in remission. Clinical Lessons: This case of metastatic renal cell carcinoma to the thyroid adds to the small body of literature showing the thyroid as a possible site of RCC metastasis. The long time interval between initial RCC presentation and metastasis to the thyroid makes this diagnosis more difficult; however, clinicians should be aware of the possibility, making thyroidectomy a stronger option in cases where FNA cytology is indeterminate. Presentation: 6/2/2024

Novel Schiff Bases: Synthesis, Characterization, Bioactivity, Cytotoxicity, and Computational Evaluations

Hypopharyngeal cancer is rare subtype of head and neck cancers with relatively poor prognosis. Current therapeutic modalities lack the potential to provide patients with better clinical outcome and quality of life. This study was conducted on the synthesis of 2-methoxy-4-((3-alkyl(aryl)-5-oxo-1H-1,2,4-triazol-4(5H)-ylimino)-methyl)-phenyl-4-(2-methoxy-4-((3-alkyl(aryl)-5-oxo-1H-1,2,4-triazol-4(5H)-ylimino)-methyl)-phenyl)-4-oxobutanoates (3) using biologically important 1,2,4-triazole. The condensation of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1) with 4-formyl-2-methoxyphenyl-4-(4-formyl-2-methoxyphenyl)-4-oxobutanoate yielded the biologically active 2-methoxy-4-((3-alkyl(aryl)-5-oxo-1H-1,2,4-triazol-4(5H)-ylimino)-methyl)-phenyl-4-(2-methoxy-4-((3-alkyl(aryl)-5-oxo-1H-1,2,4-triazol-4(5H)-ylimino)-methyl)-phenyl)-4-oxobutanoates (3). The compounds obtained were analyzed via FT-IR,1H-/13C-NMR spectrometers, elemental analysis, and HRMS spectroscopic techniques. Furthermore, we aimed at investigating the potential of compounds 3a-g against FaDu hypopharyngeal cancer cells. We demonstrated that compounds 3c, 3e, and 3 g had relatively lower IC50 values compared to the remaining tested compounds and more importantly their IC50 values were comparable to 5-FU, which suggests them as important therapeutic agent candidates. These newly synthesized compounds were assessed for their inhibitory activities toward two human carbonic anhydrase isoforms I and II (hCA I and II). Then, molecular docking calculations were made to compare the biological activities of studied molecules against cancer proteins. Compound 3c has a docking score of −7.15 against squamous cell carcinoma protein with ID: 2DO4 and −5.49 docking score against squamous cell carcinoma protein with ID:5PJZ. ADME/T analysis was performed to examine the drug properties of studied molecules.

6477 Surprise Finding for a Thyroid Nodule: Metastatic Renal Cell Carcinoma

Abstract Disclosure: A. Xu: None. E. Hsu: None. Introduction: A patient with an incidental and asymptomatic thyroid nodule underwent fine needle aspiration biopsy (FNA) after the nodule increased in size. Without a definite pathology after three FNA attempts, thyroidectomy was performed, where pathology found metastatic renal cell carcinoma (RCC). Clinical Case: A 64 year old woman had a past medical history of obesity, type 2 diabetes, RCC (stage I: pT1bN0M0) treated with right radical nephrectomy five years prior and thought to be in remission, remote smoking history smoking, and coronary artery disease with coronary artery bypass graft (CABG) two months prior, on anticoagulation. The patient reported a distant history of right thyroid lobectomy over a decade prior for unclear reasons, but she was adamant that the pathology was benign. Two years prior to presentation, CT chest done for RCC surveillance had detected a left thyroid nodule. Ultrasound at the time revealed a 3.6 x 1.9 x 2.3 cm solid, isoechoic nodule in the upper left lobe, which was not taller than wide, and had smooth margins and no echogenic foci. A repeat ultrasound at the time of presentation showed interval growth of the nodule, now measuring 4.3 x 2.1 x 2.9 cm. FNA was unsatisfactory, yielding predominantly blood. Patient felt well and had no compressive neck symptoms. We opted to wait two months and repeat FNA, which resulted as atypia of undetermined significance - Bethesda category III (AUS). We recommended completion thyroidectomy, but patient preferred to avoid surgery. We decided to wait two months and repeat FNA with molecular testing. This third FNA resulted AUS again; however, due to non-medical reasons, molecular testing was not performed. Another ultrasound showed slight growth of the nodule, 5.1 x 2.9 x 2.0 cm, which appeared hypoechoic now, but was still not taller than wide, with smooth margins and no echogenic foci. Completion thyroidectomy was performed, with pathology showing metastatic clear cell renal cell carcinoma. Immunostains were positive for carbonic anhydrase and renal cell carcinoma marker and negative for TTF-1. Whole-body PET-CT showed no hypermetabolic foci, and a repeat PET-CT one year later still showed no evidence of metastatic disease. Other than a hospitalization for COVID-19, patient is doing well and asymptomatic now over a year after her thyroidectomy. Oncology will continue routine surveillance imaging for her metastatic renal cell carcinoma thought to be in remission. Clinical Lessons: This case of metastatic renal cell carcinoma to the thyroid adds to the small body of literature showing the thyroid as a possible site of RCC metastasis. The long time interval between initial RCC presentation and metastasis to the thyroid makes this diagnosis more difficult; however, clinicians should be aware of the possibility, making thyroidectomy a stronger option in cases where FNA cytology is indeterminate. Presentation: 6/2/2024