Design and discovery of new antiproliferative 1,2,4-triazin-3(2H)-ones as tubulin polymerization inhibitors targeting colchicine binding site

Design and synthesis of new nicotinamides as immunomodulatory VEGFR-2 inhibitors and apoptosis inducers

Background: Nicotinamide-based VEGFR-2 inhibitors have good contribution in drug discovery.Aim: Development of novel nicotinamides as VEGFR-2 inhibitors.Methods: different in vitro and in silico assays were conducted to evaluate the VEGFR-2 inhibition and cytotoxicity.Results: Compound 16c displayed strongest anti-VEGFR-2 potentiality and good anti-proliferative effects. Compound 16c enhanced apoptosis and caused cell cycle arrest in the Pre-G1 and S phases. Compound 16c boosted the level of the apoptotic caspase-3 and inhibited the level of TNF-α and IL-6 in tumor cells. Molecular docking and molecular dynamics (MD) simulations indicated the outstanding binding potential of compound 16c against VEGFR-2.Conclusion: Compound 16c is a good candidate for the creation of a novel antiangiogenic lead anticancer medication.

Tetrahydrocarbazoles incorporating 5-arylidene-4-thiazolinones as potential antileukemia and antilymphoma targeting tyrosine kinase and tubulin polymerase enzymes: Design, synthesis, structural, biological and molecular docking studies

Finding effective and selective anticancer agents is a top medical priority due to high clinical treatment demand. However, current anticancer agents have serious side effects and resistance development remains a big concern. This creates an urgent need for new multitarget drugs that could solve these problems. Tetrahydrocarbazoles and 5-arylidene-4-thiazolinones have always attracted researchers for their multifaced anticancer activities and the possibility to be easily derivatized. Thereby, herein we report the combination of the two scaffolds to provide compounds 9a-j and 10a-j that were fully characterized and their tautomeric form was confirmed by crystal structure. 9a-j and 10a-j wereassessedfor invitro antiproliferative activityusing SRB assay against a panel of seven human cancer cell lines with doxorubicin as the standard. The results revealed that the cell lines derived from leukemia (Jurkat) and lymphoma (U937) are the most sensitive. Compounds 9d, 10e, 10g, and 10f revealed the highest potency (IC50 = 3.11-11.89 μM) with much lower effects on normal lymphocytes cell line (IC50 > 50 µM). The results show that modifications at 6th position of the THC and the nature of the substituent at the arylidene moiety affect the activity. To exploit the mode of action, 9d, 10e, 10f, and 10g were evaluated as VEGFR-2 and EGFR inhibitors. 10e is the most potent (IC50 0.26 and 0.14 μM) against both enzymes. It also induced G0-G1-phase cell cycle arrest and apoptosis. While 10g exhibited higher potency (IC50 9.95 μM) than vincristine (IC50 15.63 μM) against tubulin. A molecular docking study was carried out to understand the interactions between 10e, 10g and their targets. This study reveals 10e and 10g as possible candidates for developing multitarget anticancer agents against leukemia and lymphoma.

QSAR, ADMET, molecular docking, and dynamics studies of 1,2,4-triazine-3(2H)-one derivatives as tubulin inhibitors for breast cancer therapy

Breast cancer remains a leading cause of cancer-related deaths among women globally, necessitating the development of more effective therapeutic agents with minimal side effects. This study explores novel 1,2,4-triazine-3(2H)-one derivatives as potential inhibitors of Tubulin, a pivotal protein in cancer cell division, highlighting a targeted approach in cancer therapy. Using an integrated computational approach, we combined quantitative structure-activity relationship (QSAR) modeling, ADMET profiling, molecular docking, and molecular dynamics simulations to evaluate and predict the efficacy and stability of these compounds. Our QSAR models, developed through rigorous statistical analysis, revealed that descriptors such as absolute electronegativity and water solubility significantly influence inhibitory activity, achieving a predictive accuracy (R2) of 0.849. Molecular docking studies identified compounds with high binding affinities, particularly Pred28, which exhibited the best docking score of - 9.6 kcal/mol. Molecular dynamics simulations conducted over 100 ns provided further insights into the stability of these interactions. Pred28 demonstrated notable stability, with the lowest root mean square deviation (RMSD) of 0.29 nm and root mean square fluctuation (RMSF) values indicative of a tightly bound conformation to Tubulin. The novelty of this work lies in its methodological rigor and the integration of multiple advanced computational techniques to pinpoint compounds with promising therapeutic potential. Our findings advance the current understanding of Tubulin inhibitors and open avenues for the synthesis and experimental validation of these compounds, aiming to offer new solutions for breast cancer treatment.

Discovery of new thiazolidine-2,4-dione derivatives as potential VEGFR-2 inhibitors: In vitro and in silico studies

In this study, a series of seven novel 2,4-dioxothiazolidine derivatives with potential anticancer and VEGFR-2 inhibiting abilities were designed and synthesized as VEGFR-2 inhibitors. The synthesized compounds were tested in vitro for their potential to inhibit VEGFR-2 and the growth of HepG2 and MCF-7 cancer cell lines. Among the compounds tested, compound 22 (IC50 = 0.079 μM) demonstrated the highest anti-VEGFR-2 efficacy. Furthermore, it demonstrated significant anti-proliferative activities against HepG2 (IC50 = 2.04 ± 0.06 μM) and MCF-7 (IC50 = 1.21 ± 0.04 M). Additionally, compound 22 also increased the total apoptotic rate of the MCF-7 cancer cell lines with cell cycle arrest at S phase. As well, computational methods were applied to study the VEGFR-2-22 complex at the molecular level. Molecular docking and molecular dynamics (MD) simulations were used to investigate the complex's structural and kinetic characteristics. The DFT calculations further revealed the structural and electronic properties of compound 22. Finally, computational ADMET and toxicity tests were performed indicating the likeness of the proposed compounds to be drugs. The results suggest that compound 22 displays promise as an effective anticancer treatment and can serve as a model for future structural modifications and biological investigations in this field.

Anti-rheumatic colchicine phytochemical exhibits potent antiviral activities against avian and seasonal Influenza A viruses (IAVs) via targeting different stages of IAV replication cycle

BACKGROUND

The continuous evolution of drug-resistant influenza viruses highlights the necessity for repurposing naturally-derived and safe phytochemicals with anti-influenza activity as novel broad-spectrum anti-influenza medications.

METHODS

In this study, nitrogenous alkaloids were tested for their viral inhibitory activity against influenza A/H1N1 and A/H5N1 viruses. The cytotoxicity of tested alkaloids on MDCK showed a high safety range (CC50 > 200 µg/ml), permitting the screening for their anti-influenza potential.

RESULTS

Herein, atropine sulphate, pilocarpine hydrochloride and colchicine displayed anti-H5N1 activities with IC50 values of 2.300, 0.210 and 0.111 µg/ml, respectively. Validation of the IC50 values was further depicted by testing the three highly effective alkaloids, based on their potent IC50 values against seasonal influenza A/H1N1 virus, showing comparable IC50 values of 0.204, 0.637 and 0.326 µg/ml, respectively. Further investigation suggests that colchicine could suppress viral infection by primarily interfering with IAV replication and inhibiting viral adsorption, while atropine sulphate and pilocarpine hydrochloride could directly affect the virus in a cell-free virucidal effect. Interestingly, the in silico molecular docking studies suggest the abilities of atropine, pilocarpine, and colchicine to bind correctly inside the active sites of the neuraminidases of both influenza A/H1N1 and A/H5N1 viruses. The three alkaloids exhibited good binding energies as well as excellent binding modes that were similar to the co-crystallized ligands. On the other hand, consistent with in vitro results, only colchicine could bind correctly against the M2-proton channel of influenza A viruses (IAVs). This might explicate the in vitro antiviral activity of colchicine at the replication stage of the virus replication cycle.

CONCLUSION

This study highlighted the anti-influenza efficacy of biologically active alkaloids including colchicine. Therefore, these alkaloids should be further characterized in vivo (preclinical and clinical studies) to be developed as anti-IAV agents.

Alkaloids as Additional Weapons in the Fight against Breast Cancer: A Review

Breast carcinoma is among the most frequent cancerous tumour in females around the globe. The major modalities now employed in the therapeutic management of breast cancer include surgeries, chemotherapy, and specialized medicines. Despite their potential to help individuals' problems, they are also associated with many negative impacts. As a result, natural products are increasingly regarded to be a preferable alternative. Alkaloids are essential biochemical substances that can be used to develop new drugs. Numerous alkaloids that originate from natural plants have been shown in vitro and in vivo to have anti-proliferation and anti-metastasis actions on different kinds of carcinoma. According to the data collected in this study, the utilization of alkaloids as anti-tumor medicines appears to be extremely potent; nevertheless, extensive studies and clinical trials are required before utilizing individual alkaloids. In this overview, we provide a detailed and vital exploration of pre-existing alkaloids possessing anti-tumor activities due to bioactive compounds. This study also includes an overview of synthesized analogues and pharmacological characteristics that will be beneficial to scientists working on alkaloids for medicinal purposes. In a recent survey of the literature, alkaloids are an important component of plantderived antitumor medicines that hold great potential for the future development of cancer therapy and preventive therapies. We have also discussed structural analysis relationship (SAR) studies. Moreover, it covers clinical trial medications and FDA-approved medicines from the last five years that will be useful in further research.

New thiazolidine-2,4-diones as effective anti-proliferative and anti-VEGFR-2 agents: Design, synthesis, in vitro, docking, MD simulations, DFT, ADMET, and toxicity studies

Novel thiazolidine-2,4-dione derivatives, 11a-g, were designed, and synthesized targeting the VEGFR-2 protein. The in vitro studies indicated the abilities of the synthesized derivatives to inhibit VEGFR-2 and prevent the growth of two different cancer cell types, HepG2 and MCF-7. Compound 11 f exhibited the strongest anti-VEGFR-2 activity (IC50 = 0.053 µM). As well, compound 11 f showed impressive anti-proliferative activity against the mentioned cancer cell lines with IC50 values of 0.64 ± 0.01 and 0.53 ± 0.04 µM, respectively. Additionally, compound 11 f arrested the MCF-7 cell cycle at the S phase and increased the overall apoptosis percentage. Furthermore, cell migration assay revealed that compound 11 f has a significant ability to prevent migration and healing potentialities of MCF-7. Moreover, computational studies were used to conduct the molecular investigation of the VEGFR-2-11 f complex. The kinetic and structural features of the complex were examined using molecular dynamics simulations and molecular docking. Besides, Principal component analysis (PCA) was used to explain the dynamics of the VEGFR-2-11 f complex at various spatial scales. The DFT calculations also provided further clarity regarding compound 11 f's structural and electronic features. To evaluate how closely the developed compounds might look like drugs, ADMET and toxicity experiments were computed. To conclude, the presented study demonstrates the potential of compound 11 f as a viable anti-cancer drug, which can serve as a prototype for future structural modifications and further biological investigations.

Design, semi-synthesis, anti-cancer assessment, docking, MD simulation, and DFT studies of novel theobromine-based derivatives as VEGFR-2 inhibitors and apoptosis inducers

A group of theobromine derivatives was designed based on the key pharmacophoric characteristics of VEGFR-2 inhibitors. HepG2 and MCF-7 cancer cell lines were used to test the obtained compounds for their in vitro anti-proliferative activities. Compound 15 (2-(3,7-Dimethyl-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-1-yl)-N-(4-(1-(2-(4-hydroxybenzoyl)hydrazono)ethyl) phenyl)acetamide) was the most potent cytotoxic member against MCF-7 (IC50 = 0.42 µM) and HepG2 (IC50 = 0.22 µM). The effectiveness of VEGFR-2 inhibition was assessed for compound 15, and its IC50 value was calculated to be 0.067 µM. Additional cellular mechanistic investigations showed that compound 15 dramatically increased the population of apoptotic HepG2 cells in both early and late apoptosis. The investigation of apoptotic markers confirmed that compound 15 upregulated the levels of BAX (2.26-fold) and downregulated the levels of Bcl-2 (4.4-fold). The molecular docking investigations, MM-GPSA, PLIP studies, and MD simulations validated the potential of compound 15 to be a VEGFR-2 inhibitor. DFT calculations have been completed to comprehend how the electrical charge is distributed within compound 15 and to predict how it would bond to VEGFR-2. Lastly, ADMET prediction showed that the designed members have drug-like characteristics and minimal levels of toxicity. In conclusion, our in vitro and in silico investigations showed that compound 15 exhibited promising apoptotic anticancer potential through the suppression of VEGFR-2.

In vitro and in silico evaluation of new thieno[2,3-d]pyrimidines as anti-cancer agents and apoptosis inducers targeting VEGFR-2

In this study, new thieno[2,3-d]pyrimidine derivatives that could have potential anticancer activity by inhibiting the VEGFR-2 receptor have been designed, synthesized, and investigated. The thieno[2,3-d]pyrimidine derivatives showed strong in vitro abilities to inhibit VEGFR-2 and to prevent cancer cell growth in two different types of cancer cells, MCF-7 and HepG2. Particularly, compound 22 showed the most potent anti-VEGFR-2 activity with an IC50 value of 0.58 µM. Additionally, compound 22 exhibited good anti-proliferative activity against both MCF-7 and HepG2 cancer cell lines, with IC50 values of 11.32 ± 0.32 and 16.66 ± 1.22 µM, respectively. Further investigations revealed that compound 22 induced cell cycle arrest at the G2/M phase and promoted both early and late apoptosis in the MCF-7 cancer cells. Compound 22 also increased the level of BAX (2.8-fold), and reduced the level of Bcl-2 (2.2-fold), hence increasing the rate of apoptosis. Compound 22 also revealed 2.9-fold and 2.8-fold higher levels of caspase-8 and caspase-9, respectively, in the treated MCF-7 cancer cells compared to the control cell lines. The MD simulations showed that the VEGFR-2-22 complex was structurally and energytically stable over 100 ns, while the MM-GBSA study indicated its stable thermodynamic behavior. The bi-dimensional projection analysis confirmed the proper binding of the VEGFR-2-22 complex, while the DFT studies provided optimized geometry, charge distribution, FMO, ESP, the total density of state, and QTAIM maps of compound 22. Finally, computational ADMET studies were performed to assess the drug development potential of the thieno[2,3-d]pyrimidine derivatives. Overall, this study suggests that compound 22 has the potential as an anticancer lead compound by inhibiting VEGFR-2, which may be a guide for future drug design and development.

Synthesis and biological evaluation of novel 5-substituted/unsubstituted triazolothiadiazines as tubulin depolymerizing and vascular disrupting agents with promising antitumor activity

A novel series of 5-substituted/unsubstituted [1,2,4]triazolo[3,4-b][1,3,4] thiadiazine compounds has been achieved successfully through chemoselective reduction of the C = N bond, based on our prior work. Initial biological evaluation illustrated that the most active derivative 7j exhibited significant cell growth inhibitory activity toward MCF-7, A549, HCT116, and A2780 with the IC50 values of 0.75, 0.94, 2.90, and 4.15 μM, respectively. Most importantly, all the representative analogs did not demonstrate obvious cytotoxic activity against the non-tumoural cell line HEK-293 (IC50  > 100 μM). The mechanism study revealed that 7j caused the G2 /M phase arrest, induced cell apoptosis in HeLa cells in a concentration-dependent manner, and also showed potent tubulin polymerization inhibitory effect. Meanwhile, 7j exerted significant antivascular activity in the wound-healing and tube formation assays. These observations indicate that 5-unsubstituted 6,7-dihydro-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine scaffold might be considered as a potential lead for antitubulin inhibitors to develop highly efficient anticancer agents with potent selectivity over normal human cells.

Identification of new theobromine-based derivatives as potent VEGFR-2 inhibitors: design, semi-synthesis, biological evaluation, and in silico studies

This study aimed to design anticancer theobromine derivatives inhibiting VEGFR-2. The new compounds were tested in vitro to evaluate their effectiveness against MCF-7 and HepG2 cancer cell lines. Among these compounds, 15a showed the highest cytotoxicity against HepG2, with an IC50 value of 0.76 μM, and significant anti-proliferative effects on MCF-7, with an IC50 value of 1.08 μM. Notably, the selectivity index of 15a against the two cancer cells was 98.97 and 69.64, respectively. Moreover, 15a demonstrated potent VEGFR-2 inhibitory activity (IC50 = 0.239 μM). Further investigations revealed that 15a induced apoptosis in HepG2 cells, significantly increasing early-stage and late-stage apoptosis percentages from 3.06% and 0.71% to 29.49% and 9.63%, respectively. It also upregulated caspase-3 and caspase-9 levels by 3.45-fold and 2.37-fold, respectively compared to control HepG2 cells. Additionally, 15a inhibited the migration and wound healing ability of HepG2 cells. Molecular docking confirmed the binding affinities of the semi-synthesized compounds to VEGFR-2, consistent with in vitro results. Several computational analyses (DFT, MD simulations, MM-GBSA, PLIP, and essential dynamics) supported the stability of the 15a-VEGFR-2 complex. Overall, the biological and computational findings suggest that compound 15a could be a promising lead compound for the development of a novel apoptotic anticancer agent.

Design, synthesis, in silico studies, and biological evaluation of novel pyrimidine-5-carbonitrile derivatives as potential anti-proliferative agents, VEGFR-2 inhibitors and apoptotic inducers

A novel series of pyrimidine-5-carbonitrile derivatives bearing benzylidene and hydrazone moieties with different linkers (spacers) were designed and synthesized as possible inhibitors of the vascular endothelial growth factor receptor-2 (VEGFR-2). The newly synthesized compounds were evaluated in vitro for their cytotoxic activities against two human cancer cell lines namely colon cancer (HCT-116) and breast cancer (MCF-7) using sorafenib as a standard anticancer drug. Compounds 9d, 11e, 12b, and 12d showed higher cytotoxic activities than sorafenib with IC₅₀ values ranging from 1.14 to 10.33 μM. In particular, compound 11e exhibited excellent activities against HCT-116 and MCF-7 with IC₅₀ values of 1.14 and 1.54 μM, respectively. Moreover, compound 11e exhibited about 47.32-fold cytotoxic activity against normal human fibroblast (WI-38) cells, lower than the cytotoxicity against the cancer cells. Compounds 11e and 12b were the most potent VEGFR-2 inhibitors with IC₅₀ values of 0.61 and 0.53 μM, respectively, compared to sorafenib. Bedsides, compound 11e arrested the HCT-116 cell growth at S and sub-G1 phases, induced a significant increase in the apoptotic cells, and caused remarkable decrease in the levels of TNF-α, IL-6, and caspase-3. Finally, the binding patterns of the target derivatives were investigated through the docking study against the proposed molecular target (VEGFR-2, PDB ID 1YWN). The results of molecular docking studies showed similar binding modes to sorafenib against VEGFR-2. In addition, molecular dynamic simulations revealed the stability of compound 11e in the active site for 100 ns.

Discovery of new thieno[2,3-d]pyrimidines as EGFR tyrosine kinase inhibitors for cancer treatment

Background: EGFR has been considered a vital molecular target in cancer management. Aim: The discovery of new thieno[2,3-d]pyrimidine derivatives as EGFR tyrosine kinase inhibitors. Methods: Nine derivatives were designed, synthesized and subjected to in vitro and in silico studies. Results: Compound 7a significantly inhibited the growth of HepG2 and PC3 cells for both EGFR wild-type and EGFRT790M. Compound 7a caused a significant apoptotic effect, arresting HepG2 cells' growth in the S and G2/M phases. Docking and molecular dynamics simulation studies confirmed the correct and stable binding modes of the synthesized compounds against the active sites. Conclusion: Compound 7a is a promising dual EGFR inhibitor for cancer treatment.

Heterocyclic Compounds as Synthetic Tyrosinase Inhibitors: Recent Advances

Tyrosinase is a copper-containing enzyme which is widely distributed in nature (e.g., bacteria, mammals, fungi) and involved in two consecutive steps of melanin biosynthesis. In humans, an excessive production of melanin can determine hyperpigmentation disorders as well as neurodegenerative processes in Parkinson's disease. The development of molecules able to inhibit the high activity of the enzyme remain a current topic in medicinal chemistry, because the inhibitors reported so far present several side effects. Heterocycle-bearing molecules are largely diffuse in this sense. Due to their importance as biologically active compounds, we decided to report a comprehensive review of synthetic tyrosinase inhibitors possessing heterocyclic moieties reported within the last five years. For the reader's convenience, we classified them as inhibitors of mushroom tyrosinase (Agaricus bisporus) and human tyrosinase.

Experimental Design of D-α-tocopherol polyethylene glycol 1000 succinate Stabilized Bile Salt Based Nano-vesicles for Improved Cytotoxicity and Bioavailability of Colchicine Binding Site Inhibitor Candidates: In Vitro, In silico, and Pharmacokinetic Studies

Nowadays, conventional anticancer therapy suffers many pitfalls, including drastic side effects and limited therapeutic efficacy resulting from diminished oral bioavailability. So, in an attempt to enhance their poor solubility and oral bioavailability along with the cytotoxic activity, the developed lead compounds (C1 and C2) were loaded in D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) modified vesicles adopting thin film hydration technique. The formulations of the aforementioned candidates (F1 and F2, respectively) were elected as the optimum formula with desirability values of 0.701 and 0.618, respectively. Furthermore, an outstanding enhancement in the drug's cytotoxic activity against different cancer cell lines (MCF-7, HepG-2, MDA-MB-321, A375, and MGC-803) after being included in the nano-TPGS-modified optimum formula was noticed relative to the unformulated compounds. The formula F1 showed the best cytotoxic activities against HepG-2 with an IC₅₀ = 3 µM. Furthermore, regarding MCF-7, F1 was shown to be the most potent and protective among all the tested formulations with an IC₅₀ = 6 µM. Besides, F1 exerted the best caspase 3/7 activity stimulation (around a 5-folds increase) compared to control in the MCF-7 cell line. Notably, it was disclosedthat both C1 and C2 induced cell cycle arrest at the resting S growth phase. Moreover, C1 and C2 decreased tubulin concentrations by approximately 2-folds and 6-folds, respectively. Meanwhile, the conducted molecular docking studies ensure the eligible binding affinities of the assessed compounds. Besides, MD simulations were performed for 1000 ns to confirm the docking results and study the exact behavior of the target candidates (C1 and C2) toward the CBS.

MCL-1 Inhibitor S63845 Distinctively Affects Intramedullary and Extramedullary Hematopoiesis

Conventional chemotherapy for killing cancer cells using cytotoxic drugs suffers from low selectivity, significant toxicity, and a narrow therapeutic index. Hyper-specific targeted drugs achieve precise destruction of tumors by inhibiting molecular pathways that are critical to tumor growth. Myeloid cell leukemia 1 (MCL-1), an important pro-survival protein in the BCL-2 family, is a promising antitumor target. In this study, we chose to investigate the effects of S63845, a small-molecule inhibitor that targets MCL-1, on the normal hematopoietic system. A mouse model of hematopoietic injury was constructed, and the effects of the inhibitor on the hematopoietic system of mice were evaluated via routine blood tests and flow cytometry. The results showed that S63845 affected the hematopoiesis of various lineages in the early stage of action, causing extramedullary compensatory hematopoiesis in the myeloid and megakaryocytic lineages. The maturation of the erythroid lineage in the intramedullary and extramedullary segments was blocked to varying degrees, and both the intramedullary and extramedullary lymphoid lineages were inhibited. This study provides a complete description of the effects of MCL-1 inhibitor on the intramedullary and extramedullary hematopoietic lineages, which is important for the selection of combinations of antitumor drugs and the prevention of adverse hematopoiesis-related effects.

Research progress on antitumor activity of XRP44X and analogues as microtubule targeting agents

Cancer threatens human health and life. Therefore, it is particularly important to develop safe and effective antitumor drugs. Microtubules, the main component of cytoskeleton, play an important role in maintaining cell morphology, mitosis, and signal transduction, which are one of important targets of antitumor drug research and development. Colchicine binding site inhibitors have dual effects of inhibiting proliferation and destroying blood vessels. In recent years, a series of inhibitors targeting this target have been studied and some progress has been made. XRP44X has a novel structure and overcomes some disadvantages of traditional inhibitors. It is also a multifunctional molecule that regulates not only the function of tubulin but also a variety of biological pathways. Therefore, the structure, synthesis, structure-activity relationship, and biological activity of XRP44X analogues reported in recent years were summarized in this paper, to provide a useful reference for the rational design of efficient colchicine binding site inhibitors.

An update on the recent advances and discovery of novel tubulin colchicine binding inhibitors

Microtubules, formed by α- and β-tubulin heterodimer, are considered as a major target to prevent the proliferation of tumor cells. Microtubule-targeted agents have become increasingly effective anticancer drugs. However, due to the relatively sophisticated chemical structure of taxane and vinblastine, their application has faced numerous obstacles. Conversely, the structure of colchicine binding site inhibitors (CBSIs) is much easier to be modified. Moreover, CBSIs have strong antiproliferative effect on multidrug-resistant tumor cells and have become the mainstream research orientation of microtubule-targeted agents. This review focuses mainly on the recent advances of CBSIs during 2017-2022, attempts to depict their biological activities to analyze the structure-activity relationships and offers new perspectives for designing next generation of novel CBSIs.

New benzoxazole derivatives as potential VEGFR-2 inhibitors and apoptosis inducers: design, synthesis, anti-proliferative evaluation, flowcytometric analysis, and in silico studies

A new series of benzoxazole derivatives were designed and synthesised to have the main essential pharmacophoric features of VEGFR-2 inhibitors. Cytotoxic activities were evaluated for all derivatives against two human cancer cell lines, MCF-7 and HepG2. Also, the effect of the most cytotoxic derivatives on VEGFR-2 protein concentration was assessed by ELISA. Compounds 14o, 14l, and 14b showed the highest activities with VEGFR-2 protein concentrations of 586.3, 636.2, and 705.7 pg/ml, respectively. Additionally, the anti-angiogenic property of compound 14b against human umbilical vascular endothelial cell (HUVEC) was performed using a wound healing migration assay. Compound 14b reduced proliferation and migratory potential of HUVEC cells. Furthermore, compound 14b was subjected to further biological investigations including cell cycle and apoptosis analyses. Compound 14b arrested the HepG2 cell growth at the Pre-G1 phase and induced apoptosis by 16.52%, compared to 0.67% in the control (HepG2) cells. The effect of apoptosis was buttressed by a 4.8-fold increase in caspase-3 level compared to the control cells. Besides, different in silico docking studies were also performed to get better insights into the possible binding mode of the target compounds with VEGFR-2 active sites.

Design, synthesis and biological evaluation of novel diarylpyridine derivatives as tubulin polymerisation inhibitors

A set of novel diarylpyridines as anti-tubulin agents were designed, synthesised using a rigid pyridine as a linker to fix the cis-orientation of ring-A and ring-B. All of the target compounds were evaluated for their in vitro antiproliferative activities. Among them, 10t showed remarkable antiproliferative activities against three cancer cell lines (HeLa, MCF-7 and SGC-7901) in sub-micromolar concentrations. Consistent with its potent antiproliferative activity, 10t also displayed potent anti-tubulin activity. Cellular mechanism investigation elucidated 10t disrupted the cellular microtubule structure, arrested cell cycle at G2/M phase and induces apoptosis. Molecular modelling studies showed that 10t could bind to the colchicine binding site on microtubules. These results provide motivation and further guidance for the development of new CA-4 analogues.

1,3,4-Oxadiazole-naphthalene hybrids as potential VEGFR-2 inhibitors: design, synthesis, antiproliferative activity, apoptotic effect, and in silico studies

In the current work, some 1,3,4-oxadiazole-naphthalene hybrids were designed and synthesised as VEGFR-2 inhibitors. The synthesised compounds were evaluated in vitro for their antiproliferative activity against two human cancer cell lines namely, HepG-2 and MCF-7. Compounds that exhibited promising cytotoxicity (5, 8, 15, 16, 17, and 18) were further evaluated for their VEGFR-2 inhibitory activities. Compound 5 showed good antiproliferative activity against both cell lines and inhibitory effect on VEGFR-2. Besides, it induced apoptosis by 22.86% compared to 0.51% in the control (HepG2) cells. This apoptotic effect was supported by a 5.61-fold increase in the level of caspase-3 compared to the control cells. Moreover, it arrested the HepG2 cell growth mostly at the Pre-G1 phase. Several in silico studies were performed including docking, ADMET, and toxicity studies to predict binding mode against VEGFR-2 and to anticipate pharmacokinetic, drug-likeness, and toxicity of the synthesised compounds.

Evaluation of 3,5-Diphenyl-2-Pyrazolines for Antimitotic Activity by Inhibition of Tubulin Polymerization

Chalcones have a skeleton of diphenyls connected via an α,β-unsaturated carbonyl group. Many chalcone derivatives have been shown to interact with tubulin. Based on previous reports, chalcones derived by substitution of a carbonyl group with 2-pyrazoline can be expected to inhibit tubulin polymerization. Therefore, 3,5-diphenyl-2-pyrazolines were prepared to investigate their ability to inhibit tubulin polymerization. The clonogenic long-term survival assay showed that derivative 4, 5-(3,5-dimethoxyphenyl)-3-(2-methoxyphenyl)-4,5-dihydro-1H-pyrazole-1-carbothioamide, was the most effective at inhibiting the clonogenicity of HCT116 human colon cancer cells. Derivative 4 induced G2/M cell cycle arrest. In addition, derivative 4 caused dispersed microtubules, a disorganized spherical arrangement of chromosomes, and inhibition of mitotic spindle formation. The binding mode between tubulin and derivative 4 was elucidated by in silico molecular docking. Derivative 4 was superimposed with colchicine and entered the colchicine-binding site well. These results suggest that derivative 4 inhibits tubulin polymerization by binding to the colchicine binding site of tubulin, thus preventing mitotic spindle formation during mitosis in HCT116 colon cancer cells. We propose that derivative 4 could be used as a promising antimitotic chemotherapeutic agent.

Discovery of New VEGFR-2 Inhibitors: Design, Synthesis, Anti-Proliferative Evaluation, Docking, and MD Simulation Studies

Four new nicotinamide-based derivatives were designed as antiangiogenic VEGFR-2 inhibitors. The congeners were synthesized possessing the pharmacophoric essential features to bind correctly with the VEGFR-2 active pocket. All members were evaluated for their cytotoxic and VEGFR-2 inhibitory potentialities. Compound 6 was the most potent showingIC50 values of 9.3 ± 0.02 and 7.8 ± 0.025 µM against HCT-116 and HepG-2 cells, respectively, and IC50 of 60.83 nM regarding VEGFR-2 enzyme inhibition. Compound 6 arrested the growth of HCT-116 cells at the pre-G1 and G2-M phases. Further, it induced both early and late apoptosis. Additionally, compound 6 caused a significant decrease in TNF-α and IL6 by 66.42% and 57.34%, respectively. The considered compounds had similar docking performances to that of sorafenib against the VEGFR-2 (PDB ID: 2OH4). The correct binding of compound 6 with VEGFR-2 was validated using MD simulations, and MM-GPSA calculations.

Design, synthesis and biological evaluation of 9-aryl-5H-pyrido[4,3-b]indole derivatives as potential tubulin polymerization inhibitors

A series of new 9-aryl-5H-pyrido[4,3-b]indole derivatives as tubulin polymerization inhibitors were designed, synthesized, and evaluated for antitumor activity. All newly prepared compounds were tested for their anti-proliferative activity in vitro against three different cancer cells (SGC-7901, HeLa, and MCF-7). Among the designed compounds, compound 7k displayed the strongest anti-proliferative activity against HeLa cells with IC₅₀ values of 8.7 ± 1.3 μM. In addition, 7k could inhibit the polymerization of tubulin and disrupt the microtubule network of cells. Further mechanism studies revealed that 7k arrested cell cycle at the G2/M phase and induced apoptosis in a dose-dependent manner. Molecular docking analysis confirmed that 7k may bind to colchicine binding sites on microtubules. Our study aims to provide a new strategy for the development of antitumor drugs targeting tubulin.

Discovery of Some Heterocyclic Molecules as Bone Morphogenetic Protein 2 (BMP-2)-Inducible Kinase Inhibitors: Virtual Screening, ADME Properties, and Molecular Docking Simulations

Bone morphogenetic proteins (BMPs) are growth factors that have a vital role in the production of bone, cartilage, ligaments, and tendons. Tumors’ upregulation of bone morphogenetic proteins (BMPs) and their receptors are key features of cancer progression. Regulation of the BMP kinase system is a new promising strategy for the development of anti-cancer drugs. In this work, based on a careful literature study, a library of benzothiophene and benzofuran derivatives was subjected to different computational techniques to study the effect of chemical structure changes on the ability of these two scaffolds to target BMP-2 inducible kinase, and to reach promising candidates with proposed activity against BMP-2 inducible kinase. The results of screening against Lipinski’s and Veber’s Rules produced twenty-one outside eighty-four compounds having drug-like molecular nature. Computational ADMET studies favored ten compounds (11, 26, 27, 29, 30, 31, 34, 35, 65, and 72) with good pharmacokinetic profile. Computational toxicity studies excluded compound 34 to elect nine compounds for molecular docking studies which displayed eight compounds (26, 27, 29, 30, 31, 35, 65, and 72) as promising BMP-2 inducible kinase inhibitors. The nine fascinating compounds will be subjected to extensive screening against serine/threonine kinases to explore their potential against these critical proteins. These promising candidates based on benzothiophene and benzofuran scaffolds deserve further clinical investigation as BMP-2 kinase inhibitors for the treatment of cancer.

Antiproliferative Potential of Gloriosine: A Lead for Anticancer Drug Development

Gloriosine, a colchicine-like natural product, is widely obtained from Gloriosa superba roots. Despite having remarkable anticancer potential, colchicine could not pave its way to the clinic, while gloriosine is yet to be investigated for its pharmacological effects. In the present work, 14 compounds, including gloriosine, were isolated from the G. superba roots and were characterized by NMR spectroscopy. Gloriosine (11) was evaluated for its antiproliferative activity against a panel of 15 human cancer cell lines of different tissues and normal breast cells. Gloroisine (11) displayed significant antiproliferative activity against various cancer cell lines selectively, with IC₅₀ values ranging from 32.61 to 100.28 nM. Further, gloriosine (11) was investigated for its apoptosis-inducing ability and found to form apoptotic bodies. It also inhibited A549 cell migration in the wound healing assay. Finally, molecular docking studies were performed to explore the possible binding modes of gloriosine with the colchicine-binding site of tubulin protein. Our findings suggested that gloriosine might be a potential lead for anticancer drug discovery.

Structure-Based Virtual Screening, Docking, ADMET, Molecular Dynamics, and MM-PBSA Calculations for the Discovery of Potential Natural SARS-CoV-2 Helicase Inhibitors from the Traditional Chinese Medicine

Continuing our antecedent work against COVID-19, a set of 5956 compounds of traditional Chinese medicine have been virtually screened for their potential against SARS-CoV-2 helicase (PDB ID: 5RMM). Initially, a fingerprint study with VXG, the ligand of the target enzyme, disclosed the similarity of 187 compounds. Then, a molecular similarity study declared the most similar 40 compounds. Subsequently, molecular docking studies were carried out to examine the binding modes and energies. Then, the most appropriate 26 compounds were subjected to in silico ADMET and toxicity studies to select the most convenient inhibitors to be: (1R,2S)-ephedrine (57), (1R,2S)-norephedrine (59), 2-(4-(pyrrolidin-1-yl)phenyl)acetic acid (84), 1-phenylpropane-1,2-dione (195), 2-methoxycinnamic acid (246), 2-methoxybenzoic acid (364), (R)-2-((R)-5-oxopyrrolidin-3-yl)-2-phenylacetic acid (405), (Z)-6-(3-hydroxy-4-methoxystyryl)-4-methoxy-2H-pyran-2-one (533), 8-chloro-2-(2-phenylethyl)-5,6,7-trihydroxy-5,6,7,8-tetrahydrochromone (637), 3-((1R,2S)-2-(dimethylamino)-1-hydroxypropyl)phenol (818), (R)-2-ethyl-4-(1-hydroxy-2-(methylamino)ethyl)phenol (5159), and (R)-2-((1S,2S,5S)-2-benzyl-5-hydroxy-4-methylcyclohex-3-en-1-yl)propane-1,2-diol (5168). Among the selected 12 compounds, the metabolites, compound 533 showed the best docking scores. Interestingly, the MD simulation studies for compound 533, the one with the highest docking score, over 100 ns showed its correct binding to SARS-CoV-2 helicase with low energy and optimum dynamics. Finally, MM-PBSA studies showed that 533 bonded favorably to SARS-CoV-2 helicase with a free energy value of −83 kJ/mol. Further, the free energy decomposition study determined the essential amino acid residues that contributed favorably to the binding process. The obtained results give a huge hope to find a cure for COVID-19 through further in vitro and in vivo studies for the selected compounds.

Modified Benzoxazole-Based VEGFR-2 Inhibitors and Apoptosis Inducers: Design, Synthesis, and Anti-Proliferative Evaluation

This work is one of our efforts to discover potent anticancer agents. We modified the most promising derivative of our previous work concerned with the development of VEGFR-2 inhibitor candidates. Thirteen new compounds based on benzoxazole moiety were synthesized and evaluated against three human cancer cell lines, namely, breast cancer (MCF-7), colorectal carcinoma (HCT116), and hepatocellular carcinoma (HepG2). The synthesized compounds were also evaluated against VEGFR-2 kinase activity. The biological testing fallouts showed that compound 8d was more potent than standard sorafenib. Such compound showed IC50 values of 3.43, 2.79, and 2.43 µM against the aforementioned cancer cell lines, respectively, compared to IC50 values of 4.21, 5.30, and 3.40 µM reported for sorafenib. Compound 8d also was found to exert exceptional VEGFR-2 inhibition activity with an IC50 value of 0.0554 μM compared to sorafenib (0.0782 μM). In addition, compound 8h revealed excellent cytotoxic effects with IC50 values of 3.53, 2.94, and 2.76 µM against experienced cell lines, respectively. Furthermore, compounds 8a and 8e were found to inhibit VEGFR-2 kinase activity with IC50 values of 0.0579 and 0.0741 μM, exceeding that of sorafenib. Compound 8d showed a significant apoptotic effect and arrested the HepG2 cells at the pre-G1 phase. In addition, it exerted a significant inhibition for TNF-α (90.54%) and of IL-6 (92.19%) compared to dexamethasone (93.15%). The molecular docking studies showed that the binding pattern of the new compounds to VEGFR-2 kinase was similar to that of sorafenib.

A Multistage In Silico Study of Natural Potential Inhibitors Targeting SARS-CoV-2 Main Protease

Among a group of 310 natural antiviral natural metabolites, our team identified three compounds as the most potent natural inhibitors against the SARS-CoV-2 main protease (PDB ID: 5R84), Mpro. The identified compounds are sattazolin and caprolactin A and B. A validated multistage in silico study was conducted using several techniques. First, the molecular structures of the selected metabolites were compared with that of GWS, the co-crystallized ligand of Mpro, in a structural similarity study. The aim of this study was to determine the thirty most similar metabolites (10%) that may bind to the Mpro similar to GWS. Then, molecular docking against Mpro and pharmacophore studies led to the choice of five metabolites that exhibited good binding modes against the Mpro and good fit values against the generated pharmacophore model. Among them, three metabolites were chosen according to ADMET studies. The most promising Mpro inhibitor was determined by toxicity and DFT studies to be caprolactin A (292). Finally, molecular dynamics (MD) simulation studies were performed for caprolactin A to confirm the obtained results and understand the thermodynamic characteristics of the binding. It is hoped that the accomplished results could represent a positive step in the battle against COVID-19 through further in vitro and in vivo studies on the selected compounds.

New [1,2,4]triazolo[4,3-c]quinazoline derivatives as vascular endothelial growth factor receptor-2 inhibitors and apoptosis inducers: Design, synthesis, docking, and antiproliferative evaluation

In continuation of our previous efforts in the field of design and synthesis of vascular endothelial growth factor receptor (VEGFR)-2 inhibitors, a new series of [1,2,4]triazolo[4,3-c]quinazoline derivatives were designed and synthesized as modified analogs of some reported VEGFR-2 inhibitors. The synthesized compounds were designed to have the essential pharmacophoric features of VEGFR-2 inhibitors. Antiproliferative activities of the synthesized compounds were investigated against two tumor cell lines (HepG2 and HCT-116) using sorafenib as a positive control. Compound 10k emerged as the most promising antiproliferative agent with IC₅₀ values of 4.88 and 5.21 µM against HepG2 and HCT-116 cells, respectively. Also, it showed the highest inhibitory activity against VEGFR-2 with an IC₅₀ value of 53.81 nM compared to sorafenib (IC₅₀  = 44.34 nM). Cell cycle analysis revealed that compound 10k can arrest HepG2 cells at both the S and G2/M phases. In addition, this compound produced a tenfold increase in apoptotic cells compared to the control. Furthermore, the effect of compound 10k on the expression level of BAX, Bcl-2, and caspase-3 was assessed. This compound caused a 3.35-fold increase in BAX expression levels and a 1.25-fold reduction in Bcl-2 expression levels. The BAX/Bcl-2 ratio was calculated to be 4.57, indicating a promising apoptotic effect. It also showed a significant increase in the level of caspase-3 (4.12-fold) compared to the control cells. In silico docking, absorption, distribution, metabolism, excretion, and toxicity, and toxicity studies were performed for the synthesized compounds to investigate their binding patterns against the proposed biological target (VEGFR-2) and to assess the drug-likeness characters.

Anticancer, antioxidant activities and molecular docking study of thiazolidine-4-one and thiadiazol derivatives

Liver cancer accounts for a major portion of the global cancer burden. In many nations, the prevalence of this condition has risen in recent decades. New series of thiazolidinones and thiadiazolidine have been designed, synthesized, and evaluated for potential antioxidant and antihepatocarcinogenic activity. The antioxidant activity was evaluated using a DPPH assay. Furthermore, we examined the compounds against Hepg-2 cells using MTT assay, flow cytometry analysis through the cell cycle, reactive oxygen species, and apoptosis. The result showed that compound 6b has the highest antioxidant activity with IC₅₀ = 60.614 ± 0.739 µM. The anticancer activity showed that compounds 5 and 6b have significant toxicity against liver cancer cells Hepg2, IC₅₀ values (9.082 and 4.712) µM, respectively. Flow cytometry experiments revealed that compound 5 arrested Hepg-2 cells in the S process, while compound 6b arrested Hepg-2 cells in the G1. Compound 6b had a greater reduction in reactive oxygen species and late apoptosis than compound 5. Substantially, compound 5 had affinity energies of -7.6 and -8.5 for Akt and CDK4 proteins, respectively, but compound 6b had affinity energies of -7.8 and -10.1 for Akt1 and CDK4 proteins, respectively. Consequently, compound 6b had lower binding energies than compound 5. In this work, we used multiple bioinformatics methods to shed light on the prospective therapeutic use of these series as novel candidates to target immune cells in the tumor microenvironment of hepatocellular carcinomas such as CD8+ T cells, endothelial cells, and hematopoietic stem cells.

Multi-Phase In Silico Discovery of Potential SARS-CoV-2 RNA-Dependent RNA Polymerase Inhibitors among 3009 Clinical and FDA-Approved Related Drugs

Proceeding our prior studies of SARS-CoV-2, the inhibitory potential against SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) has been investigated for a collection of 3009 clinical and FDA-approved drugs. A multi-phase in silico approach has been employed in this study. Initially, a molecular fingerprint experiment of Remdesivir (RTP), the co-crystallized ligand of the examined protein, revealed the most similar 150 compounds. Among them, 30 compounds were selected after a structure similarity experiment. Subsequently, the most similar 30 compounds were docked against SARS-CoV-2 RNA-dependent RNA polymerase (PDB ID: 7BV2). Aloin 359, Baicalin 456, Cefadroxil 1273, Sophoricoside 1459, Hyperoside 2109, and Vitexin 2286 exhibited the most precise binding modes, as well as the best binding energies. To confirm the obtained results, MD simulations experiments have been conducted for Hyperoside 2109, the natural flavonoid glycoside that exhibited the best docking scores, against RdRp (PDB ID: 7BV2) for 100 ns. The achieved results authenticated the correct binding of 2109, showing low energy and optimum dynamics. Our team presents these outcomes for scientists all over the world to advance in vitro and in vivo examinations against COVID-19 for the promising compounds.

Topo II inhibition and DNA intercalation by new phthalazine-based derivatives as potent anticancer agents: design, synthesis, anti-proliferative, docking, and in vivo studies

This research presents the design and synthesis of a novel series of phthalazine derivatives as Topo II inhibitors, DNA intercalators, and cytotoxic agents. In vitro testing of the new compounds against HepG-2, MCF-7, and HCT-116 cell lines confirmed their potent cytotoxic activity with low IC₅₀ values. Topo II inhibition and DNA intercalating activities were evaluated for the most cytotoxic members. IC₅₀ values determination demonstrated Topo II inhibitory activities and DNA intercalating affinities of the tested compounds at a micromolar level. Amongst, compound 9d was the most potent member. It inhibited Topo II enzyme at IC₅₀ value of 7.02 ± 0.54 µM with DNA intercalating IC₅₀ of 26.19 ± 1.14 µM. Compound 9d was then subjected to an in vivo antitumor examination. It inhibited tumour proliferation reducing solid tumour volume and mass. Additionally, it restored liver enzymes, proteins, and CBC parameters near-normal, indicating a remarkable amelioration in their functions along with histopathological examinations.

Targeting VEGFR-2 by new quinoxaline derivatives: Design, synthesis, antiproliferative assay, apoptosis induction, and in silico studies

Twelve new triazolo[4,3-a]quinoxaline-based compounds are reported as anticancer agents with potential effects against vascular endothelial growth factor receptor-2 (VEGFR-2), using sorafenib as a reference molecule. With sorafenib as the positive control, the antiproliferative effects of the synthesized compounds against MCF-7 and HepG2 cells, as well as their VEGFR-2-inhibitory activities, were assessed. The most powerful VEGFR-2 inhibitor was compound 14a, which had an IC₅₀ value of 3.2 nM, which is very close to that of sorafenib (IC₅₀  = 3.12 nM). Furthermore, compounds 14c and 15d showed potential inhibitory activity against VEGFR-2, with IC₅₀ values of 4.8 and 5.4 nM, respectively. Compound 14a caused apoptosis in HepG2 cells and stopped the cell cycle at the G2/M phase. In HepG2 cells, it also increased the levels of the proteases caspase-3 and caspase-9, as well as the Bax/Bcl-2 ratio. In silico ADMET (absorption, distribution, metabolism, excretion, and toxicity) and toxicity experiments revealed that the synthesized agents had acceptable drug-likeness.

Discovery of new 3-methylquinoxalines as potential anti-cancer agents and apoptosis inducers targeting VEGFR-2: design, synthesis, and in silico studies

There is an urgent need to design new anticancer agents that can prevent cancer cell proliferation even with minimal side effects. Accordingly, two new series of 3-methylquinoxalin-2(1H)-one and 3-methylquinoxaline-2-thiol derivatives were designed to act as VEGFR-2 inhibitors. The designed derivatives were synthesised and evaluated in vitro as cytotoxic agents against two human cancer cell lines namely, HepG-2 and MCF-7. Also, the synthesised derivatives were assessed for their VEGFR-2inhibitory effect. The most promising member 11e were further investigated to reach a valuable insight about its apoptotic effect through cell cycle and apoptosis analyses. Moreover, deep investigations were carried out for compound 11e using western-plot analyses to detect its effect against some apoptotic and apoptotic parameters including caspase-9, caspase-3, BAX, and Bcl-2. Many in silico investigations including docking, ADMET, toxicity studies were performed to predict binding affinity, pharmacokinetic, drug likeness, and toxicity of the synthesised compounds. The results revealed that compounds 11e, 11g, 12e, 12g, and 12k exhibited promising cytotoxic activities (IC50 range is 2.1 - 9.8 µM), comparing to sorafenib (IC50 = 3.4 and 2.2 µM against MCF-7 and HepG2, respectively). Moreover, 11b, 11f, 11g, 12e, 12f, 12g, and 12k showed the highest VEGFR-2 inhibitory activities (IC50 range is 2.9 - 5.4 µM), comparing to sorafenib (IC50 = 3.07 nM). Additionally, compound 11e had good potential to arrest the HepG2 cell growth at G2/M phase and to induce apoptosis by 49.14% compared to the control cells (9.71%). As well, such compound showed a significant increase in the level of caspase-3 (2.34-fold), caspase-9 (2.34-fold), and BAX (3.14-fold), and a significant decrease in Bcl-2 level (3.13-fold). For in silico studies, the synthesised compounds showed binding mode similar to that of the reference compound (sorafenib).

Recent Trends in Tubulin-Binding Combretastatin A-4 Analogs for Anticancer Drug Development

Although significant progress over several decades has been evidenced in cancer therapy, there still remains a need for the development of novel and effective therapeutic strategies to treat several relapsed and intractable cancers. In this regard, tubulin protein has become one of the efficient and major targets for anticancer drug discovery. Considering the antimitotic ability, several tubulin inhibitors have been developed to act against various cancers. Among various tubulin inhibitors available, combretastatin-A4 (CA-4), a naturally occurring lead molecule, offers exceptional cytotoxicity (including the drug-resistant cell lines) and antivascular effects. Although CA-4 offers exceptional therapeutic efficacy, several new advancements have been proposed, such as the structural modification via A and B rings, as well as cis-olefinic bridging, which provide highly efficient analogs with improved tubulin-binding efficiency to meet the anticancer drug development requirements. This review systematically emphasizes the recent trends and latest developments in the anticancer drug design & discovery, using CA-4 analogs as the tubulin inhibiting agents, highlighting their structure-activity relationships (SAR) and resultant pharmacological efficacies.

Inhibition of Vascular Smooth Muscle and Cancer Cell Proliferation by New VEGFR Inhibitors and Their Immunomodulator Effect: Design, Synthesis, and Biological Evaluation

Abnormal vascular smooth muscle cell (VSMC) proliferation has an important role in the pathogenesis of both atherosclerosis restenosis and hypertension. Vascular endothelial growth factor (VEGF) has been shown to stimulate VSMC proliferation. In addition, angiogenesis is one of the hallmarks of cancerous growth. VEGF is the key modulator for the initial stages of angiogenesis that acts through the endothelial-specific receptor tyrosine kinases (VEGFRs). VEGFR-2 blockage is a good approach for suppression of angiogenesis. In order to discover novel VEGFR-2 TK inhibitors, we have designed and synthesized three new series of pyridine-containing compounds. The new compounds were all screened against a panel of three cell lines (HepG-2, HCT-116, and MCF-7). Promising results encouraged us to additionally evaluate the most active members for their in vitro VEGFR-2 inhibitory effect. Compound 7a, which is the most potent candidate, revealed a significant increase in caspase-3 level by 7.80-fold when compared to the control. In addition, Bax and Bcl-2 concentration levels showed an increase in the proapoptotic protein Bax (261.4 Pg/ml) and a decrease of the antiapoptotic protein Bcl-2 (1.25 Pg/ml) compared to the untreated cells. Furthermore, compound 7a arrested the cell cycle in the G2/M phase with induction of apoptosis. The immunomodulatory effect of compound 7a, the most active member, showed a reduction in TNF-α by 87%. Also, compound 7a caused a potent inhibitory effect on smooth muscle proliferation. Docking studies were also performed to get better insights into the possible binding mode of the target compounds with VEGFR-2 active sites.

In Silico Exploration of Potential Natural Inhibitors against SARS-Cov-2 nsp10

In continuation of our previous effort, different in silico selection methods were applied to 310 naturally isolated metabolites that exhibited antiviral potentialities before. The applied selection methods aimed to pick the most relevant inhibitor of SARS-CoV-2 nsp10. At first, a structural similarity study against the co-crystallized ligand, S-Adenosyl Methionine (SAM), of SARS-CoV-2 nonstructural protein (nsp10) (PDB ID: 6W4H) was carried out. The similarity analysis culled 30 candidates. Secondly, a fingerprint study against SAM preferred compounds 44, 48, 85, 102, 105, 182, 220, 221, 282, 284, 285, 301, and 302. The docking studies picked 48, 182, 220, 221, and 284. While the ADMET analysis expected the likeness of the five candidates to be drugs, the toxicity study preferred compounds 48 and 182. Finally, a density-functional theory (DFT) study suggested vidarabine (182) to be the most relevant SARS-Cov-2 nsp10 inhibitor.

New quinoxaline-based VEGFR-2 inhibitors: design, synthesis, and antiproliferative evaluation with in silico docking, ADMET, toxicity, and DFT studies

A new series of 3-methylquinoxaline-based derivatives having the same essential pharmacophoric features as VEGFR-2 inhibitors have been synthesized and evaluated for their antiproliferative activities against two human cancer cell lines, MCF-7 and HepG-2. Compounds 15b and 17b demonstrated a significant antiproliferative effect with IC₅₀ ranging from 2.3 to 5.8 μM. An enzymatic assay was carried out for all the tested candidates against VEGFR-2. Compound 17b was the most potent VEGFR-2 inhibitor (IC₅₀ = 2.7 nM). Mechanistic investigation including cell cycle arrest and apoptosis was performed for compound 17b against HepG-2 cells, and the results revealed that 17b induced cell apoptosis and arrested cell cycle in the G2/M phase. Moreover, apoptosis analyses were conducted for compound 17b to evaluate its apoptotic potential. The results showed upregulation in caspase-3 and caspase-9 levels, and improving the Bax/Bcl-2 ratio by more than 10-fold. Docking studies were performed to determine the possible interaction with the VEGFR-2 active site. Further docking studies were carried out for compound 17b against cytochrome P450 to present such compounds as non-inhibitors. In silico ADMET, toxicity, and physico-chemical properties revealed that most of the synthesized members have acceptable values of drug-likeness. Finally, DFT studies were carried out to calculate the thermodynamic, molecular orbital and electrostatic potential properties.

New quinoxaline-2(1H)-ones as potential VEGFR-2 inhibitors: design, synthesis, molecular docking, ADMET profile and anti-proliferative evaluations

Eleven new quinoxaline derivatives were designed and synthesized as modified VEGFR-2 inhibitors of our previous work.