Development of tubulin polymerization inhibitors as anticancer agents.

INTRODUCTION: Microtubules are intracellular, filamentous, polymeric structures that extend throughout the cytoplasm, composed of α-tubulin and ß-tubulin subunits. They regulate many cellular functions including cell polarity, cell shape, mitosis, intracellular transport, cell signaling, gene expression, cell integrity, and are associated with tumorigenesis. Inhibition of tubulin polymerization within tumor cells represents a crucial focus in the pursuit of developing anticancer treatments. AREAS COVERED: This review focuses on the natural product and their synthetic congeners as tubulin inhibitors along with their site of interaction on tubulin. This review also covers the developed novel tubulin inhibitors and important patents focusing on the development of tubulin inhibition for cancer treatment reported from 2018 to 2023. The scientific and patent literature has been searched on PubMed, Espacenet, ScienceDirect, and Patent Guru from 2018-2023. EXPERT OPINION: Tubulin is one of the promising targets explored extensively for drug discovery. Compounds binding in the colchicine site could be given importance because they can elude resistance mediated by the P-glycoprotein efflux pump and no colchicine site binding inhibitor is approved by FDA so far. The research on the development of antibody drug conjugates (ADCs) for tubluin polymerization inhibition could be significant strategy for cancer treatment.

Privileged Scaffolds in Drug Discovery against Human Epidermal Growth Factor Receptor 2 for Cancer Treatment.

HER2 is the membrane receptor tyrosine kinase showing overexpression in several human malignancies, particularly breast cancer. HER2 overexpression causes the activation of Ras- MAPK and PI3K/Akt/ NF-κB cellular signal transduction pathways that lead to cancer development and progression. HER2 is, therefore, presumed as one of the key targets for the development of tumor-specific therapies. Several preclinical have been developed that function by inhibiting the HER2 tyrosine kinase activity through the prevention of the dimerization process. Most HER2 inhibitors act as ATP competitors and prevent the process of phosphorylation, and abort the cell cycle progression and proliferation. In this review, the clinical drug candidates and potent pre-clinical newly developed molecules are described, and the core chemical scaffolds typically responsible for anti-HER2 activity are deciphered. In addition, the monoclonal antibodies that are either used in monotherapy or in combination therapy against HER2-positive cancer are briefly described. The identified key moieties in this study could result in the discovery of more effective HER2-targeted anticancer drug molecules and circumvent the development of resistance by HER2-specific chemotherapeutics in the future.

Discovery of Novel Hydroxyimine-Tethered Benzenesulfonamides as Potential Human Carbonic Anhydrase IX/XII Inhibitors.

To discover novel carbonic anhydrase (CA, EC 4.2.1.1) inhibitors for cancer treatment, a series of 4-{4-[(hydroxyimino)methyl]piperazin-1-yl}benzenesulfonamides were designed and synthesized using SLC-0111 as the lead molecule. The developed novel compounds 27-34 were investigated for the inhibition of human (h) isoforms hCA I, hCA II, hCA IX, and hCA XII. The hCA I was inhibited by compound 29 with a Ki value of 3.0 nM, whereas hCA II was inhibited by compound 32 with a Ki value of 4.4 nM. The tumor-associated hCA IX isoform was inhibited by compound 30 effectively with an Ki value of 43 nM, whereas the activity of another cancer-related isoform, hCA XII, was significantly inhibited by 29 and 31 with a Ki value of 5 nM. Molecular modeling showed that drug molecule 30 participates in significant hydrophobic and hydrogen bond interactions with the active site of the investigated hCAs and binds to zinc through the deprotonated sulfonamide group.

Synthesis and Anticancer Evaluation of Novel Indole Based Arylsulfonylhydrazides against Human Breast Cancer Cells.

A series of novel indole based sulfonohydrazide derivatives (5a-k) containing morpholine heterocyclic ring were synthesized through multistep chemical reactions. The target compounds (5a-k) were prepared by the reaction of substituted phenyl sulfonylhydrazides (2a-k) with morpholine derivative of indole 3-carboxaldehyde. All the target compounds were screened for their anticancer activity in vitro against the estrogen receptor-positive breast cancer line MCF-7 and triple-negative breast cancer cell line, MDA-MB-468. It was found that among all the evaluated compounds, the chemotype 4-chloro-N'-((1-(2-morpholinoethyl)-1H-indol-3-yl)methylene)benzenesulfonohydrazide (5f) showed promising inhibition of both MCF-7 and MDA-MB-468 cancer cells with the respective IC50 values of 13.2 µM and 8.2 µM. Compound 5f was found to be nontoxic against HEK 293 noncancerous cells in the studied concentration range, therefore indicating that such chemotypes inhibit the proliferation of cancerous cells selectively and significantly.

Advances in Drug Discovery against Neglected Tropical Diseases: Human African and American Trypanosomiasis.

Human African and American trypanosomiasis are the vector-borne parasitic diseases that have killed millions of people early, and many people are yet suffering from these neglected diseases. The causative agents of these infections are parasitic protozoans of the genus Trypanosoma. Current treatment regimens against these endemic diseases have several limitations in terms of safety, efficacy, route of administration, and some of them have lost efficacy due to the emergence of resistance in their respective parasites. In this review, the most promising compounds identified by different strategies of drug development against these neglected diseases including target-based approach, the phenotypic high-throughput screening, the drug repurposing approach and combination therapy are emphasized. The potent heterocyclic compounds currently undergoing pre-clinical or clinical studies have also been assessed to ascertain an effective class of organic compounds having significant therapeutic potential against these tropical diseases. The molecular hybridization of outlined motifs may result in more active compounds and circumvent the development of resistance by specific targets in future.

Deciphering the key heterocyclic scaffolds in targeting microtubules, kinases and carbonic anhydrases for cancer drug development.

Heterocyclic scaffolds are widely utilized for drug design by taking into account the molecular structure of therapeutic targets that are related to a broad spectrum of ailments, including tumors. Such compounds display various covalent and non-covalent interactions with the specific residues of the target proteins while causing their inhibition. There is a substantial number of heterocyclic compounds approved for cancer treatment, and these compounds function by interacting with different therapeutic targets involved in tumorogenesis. In this review, we trace and emphasize the privileged heterocyclic pharmacophores that have immense potency against several essential chemotherapeutic tumor targets: microtubules, kinases and carbonic anhydrases. Potent compounds currently undergoing pre-clinical and clinical studies have also been assessed for ascertaining the effective class of chemical scaffolds that have significant therapeutic potential against multiple malignancies. In addition, we also describe briefly the role of heterocyclic compounds in various chemotherapy regimens. The optimized molecular hybridization of delineated motifs may result in the discovery of more active anticancer therapeutics and circumvent the development of resistance by specific targets in the future.

Design and Development of Small-Molecule Arylaldoxime/5-Nitroimidazole Hybrids as Potent Inhibitors of MARK4: A Promising Approach for Target-Based Cancer Therapy.

Microtubule affinity-regulating kinase 4 (MARK4), a member of the serine/threonine kinase family, is an emerging therapeutic target in anticancer drug discovery paradigm due to its involvement in regulation of microtubule dynamics, cell cycle regulation, and cancer progression. Therefore, to identify the novel chemical architecture for the design and development of novel MARK4 inhibitors with concomitant radical scavenging property, a series of small-molecule arylaldoxime/5-nitroimidazole conjugates were designed and synthesized via multistep chemical reactions following the pharmacophoric hybridization approach. Compound 4h was identified as a promising MARK4 inhibitor with high selectivity toward MARK4 inhibition as compared to the panel of screened 30 kinases pertaining to the serine/threonine family, which was validated by molecular docking and fluorescence binding studies. The comprehensive cell-based examination divulged the promising apoptotic, antiproliferative, and antioxidant potential for the chemotype 4h. The compound 4h was endowed with the K a value of 3.6 × 103 M-1 for human serum albumin, which reflects its remarkable transportation and delivery properties to the target site via blood. The present study impedes that in the future, such compounds may stand as optimized pharmacological lead candidates in drug discovery for targeting cancer via MARK4 inhibition with a remarkable anticancer profile.

Synthesis, characterization and biological evaluation of tertiary sulfonamide derivatives of pyridyl-indole based heteroaryl chalcone as potential carbonic anhydrase IX inhibitors and anticancer agents.

In the quest for novel effective carbonic anhydrase inhibitors, some sulfonamide derivatives of pyridyl-indole based chalcone were synthesized and screened in vitro for inhibitory activity against human carbonic anhydrase IX isoform. Among all the synthesized compounds (SC2 -SC11), only three compounds SC3, SC7 and SC10 were found to have better binding affinity as shown by molecular docking and fluorescence binding studies. Further, the enzyme inhibition assay and in vitro anti-tumor evaluation against MCF-7 and HepG-2 cell lines revealed that the compounds SC3, SC7 and SC10 inhibited the CA IX selectively, possessed predominant anti-proliferative potential and significantly induced apoptosis in cancerous cells.