In Silico Discovery of Potential Inhibitors Targeting the RNA Binding Loop of ADAR2 and 5-HT2CR from Traditional Chinese Natural Compounds.

Adenosine deaminase acting on RNA 2 (ADAR2) is an important enzyme involved in RNA editing processes, particularly in the conversion of adenosine to inosine in RNA molecules. Dysregulation of ADAR2 activity has been implicated in various diseases, including neurological disorders (including schizophrenia), inflammatory disorders, viral infections, and cancers. Therefore, targeting ADAR2 with small molecules presents a promising therapeutic strategy for modulating RNA editing and potentially treating associated pathologies. However, there are limited compounds that effectively inhibit ADAR2 reactions. This study therefore employed computational approaches to virtually screen natural compounds from the traditional Chinese medicine (TCM) library. The shortlisted compounds demonstrated a stronger binding affinity to the ADAR2 (<-9.5 kcal/mol) than the known inhibitor, 8-azanebularine (-6.8 kcal/mol). The topmost compounds were also observed to possess high binding affinity towards 5-HT2CR with binding energies ranging from -7.8 to -12.9 kcal/mol. Further subjecting the top ADAR2-ligand complexes to molecular dynamics simulations and molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) calculations revealed that five potential hit compounds comprising ZINC000014637370, ZINC000085593577, ZINC000042890265, ZINC000039183320, and ZINC000101100339 had favorable binding free energies of -174.911, -137.369, -117.236, -67.023, and -64.913 kJ/mol, respectively, with the human ADAR2 protein. Residues Lys350, Cys377, Glu396, Cys451, Arg455, Ser486, Gln488, and Arg510 were also predicted to be crucial in ligand recognition and binding. This finding will provide valuable insights into the molecular interactions between ADAR2 and small molecules, aiding in the design of future ADAR2 inhibitors with potential therapeutic applications. The potential lead compounds were also profiled to have insignificant toxicities. A structural similarity search via DrugBank revealed that ZINC000039183320 and ZINC000014637370 were similar to naringin and naringenin, which are known adenosine deaminase (ADA) inhibitors. These potential novel ADAR2 inhibitors identified herein may be beneficial in treating several neurological disorders, cancers, viral infections, and inflammatory disorders caused by ADAR2 after experimental validation.

Molecular Docking and Dynamics Simulation Studies Predict Potential Anti-ADAR2 Inhibitors: Implications for the Treatment of Cancer, Neurological, Immunological and Infectious Diseases.

Altered RNA editing has been linked to several neurodevelopmental disorders, including autism spectrum disorder (ASD) and intellectual disability, in addition to depression, schizophrenia, some cancers, viral infections and autoimmune disorders. The human ADAR2 is a potential therapeutic target for managing these various disorders due to its crucial role in adenosine to inosine editing. This study applied consensus scoring to rank potential ADAR2 inhibitors after performing molecular docking with AutoDock Vina and Glide (Maestro), using a library of 35,161 compounds obtained from traditional Chinese medicine. A total of 47 compounds were predicted to be good binders of the human ADAR2 and had insignificant toxicity concerns. Molecular dynamics (MD) simulations, including the molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) procedure, also emphasized the binding of the shortlisted compounds. The potential compounds had plausible binding free energies ranging from -81.304 to -1068.26 kJ/mol from the MM/PBSA calculations. ZINC000085511995, a naphthoquinone had more negative binding free energy (-1068.26 kJ/mol) than inositol hexakisphosphate (IHP) [-873.873 kJ/mol], an agonist and a strong binder of ADAR2. The potential displacement of IHP by ZINC000085511995 in the IHP binding site of ADAR2 could be explored for possible deactivation of ADAR2. Bayesian-based biological activity prediction corroborates the neuropharmacological, antineoplastic and antiviral activity of the potential lead compounds. All the potential lead compounds, except ZINC000014612330 and ZINC000013462928, were predicted to be inhibitors of various deaminases. The potential lead compounds also had probability of activity (Pa) > 0.442 and probability of inactivity (Pi) < 0.116 values for treating acute neurologic disorders, except for ZINC000085996580 and ZINC000013462928. Pursuing these compounds for their anti-ADAR2 activities holds a promising future, especially against neurological disorders, some cancers and viral infections caused by RNA viruses. Molecular interaction, hydrogen bond and per-residue decomposition analyses predicted Arg400, Arg401, Lys519, Trp687, Glu689, and Lys690 as hot-spot residues in the ADAR2 IHP binding site. Most of the top compounds were observed to have naphthoquinone, indole, furanocoumarin or benzofuran moieties. Serotonin and tryptophan, which are beneficial in digestive regulation, improving sleep cycle and mood, are indole derivatives. These chemical series may have the potential to treat neurological disorders, prion diseases, some cancers, specific viral infections, metabolic disorders and eating disorders through the disruption of ADAR2 pathways. A total of nine potential lead compounds were shortlisted as plausible modulators of ADAR2.

Comparative Assessment of E-cadherin's Expression between the Metastatic and Non-metastatic Oral Squamous Cell Carcinoma: An Immunohistochemical Study

ABSTRACT Objective: To identify the clinicopathological correlation of E-cadherin expression in metastatic and non-metastatic oral squamous cell carcinoma (OSCC). Material and Methods: A total of 90 paraffin-embedded tissue sections of OSCC were retrieved from the registry. The total selected samples were 45 cases each from the primary lesions of metastatic and non-metastatic OSCC. One section was subjected to routine Hematoxylin and eosin stain and another to immunohistochemical analysis for E-cadherin expression. Results: A non-significant (p˃0.05) increased expression is seen in the non-metastatic group compared to the metastatic group, with predominantly membrane as the staining site in either group. However, the expression of E-cadherin did not reveal any statistically significant association with independent variables such as age, gender, and adverse habits of the patients (p>0.05). On the other hand, with respect to the histological differentiation of OSCC, a significant association (p<0.001) was observed with the well-differentiated type of metastatic OSCC. Conclusion: E-cadherin was useful to some extent in predicting regional metastasis. However, further studies using a panel of biomarkers with increased sample size may help us understand the process involved in metastasis.

Oral Malignant Melanoma: A Case Report.

Melanoma is a malignant neoplasm of the epidermal melanocytes. Awareness and early recognition of pigmented lesion inside oral cavity helps in initial diagnosis and further investigation and treatment. Oral malignant melanoma is a rare aggressive neoplasm commonly seen among middle age. The diagnosis of melanoma initiates from the pre-existing pigmented lesions. The poor prognosis of oral melanomas requires that pigmented lesions of undetermined origin be routinely biopsied. A case of malignant melanoma of hard palate with its clinical, radiological and histopathological presentation along with brief review is presented. Prognosis of these lesion is poor with survival rate of 5 years.

A Case of Early Ocular Manifestation of Maculopathy in a 37 year Old Male Patient of CLL.

B cell chronic lymphocytic leukemia (CLL) also called chronic lymphocytic leukemia is a disease of elderly, but in rare cases it can occur in young adults. Majority of patients present with no specific symptoms, and CLL is suspected on the basis of high total and relative lymphocyte counts, discovered on routine blood examination. This patient was referred from medicine outpatient in our institute, Era's Lucknow Medical College & Hospital for routine complete blood count. His total leukocyte count came out to be alarmingly high. The general blood picture and bone marrow examinations were consistent with CLL. On immunophenotyping CD5 and CD23 were positive. His cervical lymph nodes biopsy was reported as a case of CLL/small lymphocytic lymphoma. On his complaint of hazy vision his funduscopy revealed maculopathy. This makes our case a unique and rare one, as maculopathy in a young patient of CLL has not yet been reported from India.