Exploring the anticancer activity of functionalized isoindigos: synthesis, drug-like potential, mode of action and effect on tumor-induced xenografts

Meisoindigo Acts as a Molecular Glue to Target PKMYT1 for Degradation in Chronic Myeloid Leukemia Therapy

Meisoindigo (Mei) has been clinically utilized for the treatment of chronic myeloid leukemia (CML), yet the precise molecular targets by which it exerts effects remain unclear. Through activity-based protein profiling (ABPP), the protein kinase, membrane-associated tyrosine/threonine 1 (PKMYT1) is identified as a direct target of Mei. Specifically, Mei forms a selective and reversible covalent bond with the Cys301 residue of PKMYT1, triggering its K48-linked polyubiquitination and accelerating proteasomal degradation, which is mediated by the E3 ligase TRIM25. The study reveals that Mei acts as a molecular glue, enhancing the interaction between PKMYT1 and TRIM25 by approximately 30-fold, thereby facilitating efficient PKMYT1 degradation. Further investigations reveal the pivotal role of PKMYT1 in cell growth. Knockdown of PKMYT1 in K562 cells induces G2/M phase arrest, enhances early apoptosis, and inhibits cell proliferation. In an orthotopic xenograft model, PKMYT1 knockdown delays leukemia progression and reduces lymph node metastasis, reinforcing its role in CML progression and metastasis. These findings provide a molecular rationale for the clinical efficacy of Mei and highlight PKMYT1 as a promising therapeutic target for CML. Additionally, it offers a valuable scaffold and inspiration for the development of novel molecular glue-based protein degraders.

Iron-catalyzed selective construction of indole derivatives via oxidative C(sp3)-H functionalization of indolin-2-ones

Considering the importance of developing powerful catalysts and the pharmacophore characteristics of indole derivatives, we describe a switchable approach for the iron-catalyzed oxidative C(sp3)-H functionalization of indolin-2-ones. Selective transformations displayed excellent activity and chemoselectivity using FeCl2 as the catalyst, air as the oxidant, and alcohol as the solvent. By manipulating the reaction conditions, particularly the choice of solvent, catalyst loading, and reaction sequence, a series of valuable indole derivatives, including isatins and symmetrical and nonsymmetrical isoindigos, were selectively synthesized in good to excellent yields. Furthermore, the gram-scale synthesis of compounds with biological anticancer activity under simple conditions highlights their great potential in practical applications.

Synthesis and antitumor activity of model cyclopentene-[g]annelated isoindigos

A set of cyclopenten-[g]annelated isoindigos (5a-g) has been prepared and tested for their in vitro antiproliferative activities against MCF-7 and HL60 cells. Among, the N-1-methyl-5'-nitro derivative (5g) displayed the highest activity against HL60 cells (IC50 = 67 nM) and acted as the most potent Flt3 inhibitor. Compounds 5d-g exhibited moderate activity against MCF-7 (IC50 = 50-80 μM).

A Systems Biology-Based Approach to Uncovering Molecular Mechanisms Underlying Effects of Traditional Chinese Medicine Qingdai in Chronic Myelogenous Leukemia, Involving Integration of Network Pharmacology and Molecular Docking Technology

Background

The method of multiple targets overall control is increasingly used to predict the main active ingredient and potential target group of Chinese traditional medicines and to determine the mechanisms involved in their curative effects. Qingdai is the main traditional Chinese medicine used in the treatment of chronic myelogenous leukemia (CML), but the complex active ingredients and antitumor targets in treatment of CML have not been clearly defined in previous studies.

Material/Methods

We constructed a protein-protein interaction network diagram of CML with 638 nodes (proteins) and 1830 edges, based on the biological function of chronic myelocytic leukemia by use of Cytoscape, and we determined 19 key gene nodes in the CML molecule by network topological properties analysis in a data bank. Then, we used the Surflex-dock plugin in SYBYL7.3 docking and acquired the protein crystal structures of key genes involved in CML from the chemical composition of the traditional Chinese medicine Qingdai with key proteins in CML networks.

Results

According to the score and the spatial structure, the pharmacodynamically active ingredients of Qingdai are Isdirubin, Isoindigo, N-phenyl-2-naphthylamine, and Isatin, among which Isdirubin is the most important. We further screened the most effective activity key protein structures of CML to find the best pharmacodynamically active ingredients of Qingdai, according to the binding interactions of the inhibitors at the catalytic site performed in best docking combinations.

Conclusions

The results suggest that Isdirubin plays a role in resistance to CML by altering the expressions of PIK3CA, MYC, JAK2, and TP53 target proteins. Network pharmacology and molecular docking technology can be used to search for possible reactive molecules in traditional chinese medicines (TCM) and to elucidate their molecular mechanisms.

Nanoscale isoindigo-carriers: self-assembly and tunable properties

Over the last decade isoindigo derivatives have attracted much attention due to their high potential in pharmacy and in the chemistry of materials. In addition, isoindigo derivatives can be modified to form supramolecular structures with tunable morphologies for the use in drug delivery. Amphiphilic long-chain dialkylated isoindigos have the ability to form stable solid nanoparticles via a simple nanoprecipitation technique. Their self-assembly was investigated using tensiometry, dynamic light scattering, spectrophotometry, and fluorometry. The critical association concentrations and aggregate sizes were measured. The hydrophilic-lipophilic balance of alkylated isoindigo derivatives strongly influences aggregate morphology. In the case of short-chain dialkylated isoindigo derivatives, supramolecular polymers of 200 to 700 nm were formed. For long-chain dialkylated isoindigo derivatives, micellar aggregates of 100 to 200 nm were observed. Using micellar surfactant water-soluble forms of monosubstituted 1-hexadecylisoindigo as well as 1,1'-dimethylisoindigo were prepared for the first time. The formation of mixed micellar structures of different types in micellar anionic surfactant solutions (sodium dodecyl sulfate) was determined. These findings are of practical importance and are of potential interest for the design of drug delivery systems and new nanomaterials.

Influence of structure–property relationships of two structural isomers of thiophene-flanked diazaisoindigo on carrier-transport properties

Two structural isomers of thiophene-flanked diazaisoindigo, 6,6′-substituted 6,6′-T-DAII and 5,5′-substituted 5,5′-T-DAII, have been synthesized to study the influence of the connecting modes on the carrier-transport properties.

MediaChrom: Discovering a Class of Pyrimidoindolone-Based Polarity-Sensitive Dyes

A small library of six polarity-sensitive fluorescent dyes, nicknamed MediaChrom, was prepared. This class of dyes is characterized by a pyrimidoindolone core fitted out with a conjugated push-pull system and a carboxy linker for a conceivable coupling with biomolecules. The optimized eight-step synthetic strategy involves a highly chemo- and regioselective gold-catalyzed cycloisomerization reaction. The photophysical properties of MediaChrom dyes have been evaluated in-depth. In particular, the MediaChrom bearing a diethylamino as an electron-donating group and a trifluoromethyl as an electron-withdrawing group displays the most interesting and advantageous spectroscopic features (e.g., absorption and emission in the visible range and a good quantum yield). Promising results in terms of sensitivity have been obtained in vitro on this dye as a membrane/lipophilic probe and as a peptide fluorescent label.

Indirubin and Indirubin Derivatives for Counteracting Proliferative Diseases

Indirubin is the active component of Danggui Longhui Wan, a traditional Chinese medicine formulation. The encouraging clinical results from the 1980s obtained in chronic myelocytic leukemia patients treated with indirubin stimulated numerous studies on this compound. These investigations explored the use of indirubin in different types of cancer and reported the synthesis of novel derivatives with improved chemical and pharmacokinetic properties. In this paper, we review the impressive progress that has been made in elucidating the mechanistic understanding of how indirubin and its derivatives affect physiological and pathophysiological processes, mainly by inhibition of cell proliferation and induction of cell death. Furthermore, we survey the therapeutic use of these compounds in combating proliferative diseases such as cancer, restenosis, and psoriasis.

Synthesis and pharmacological evaluation of novel bisindole derivatives bearing oximes moiety: identification of novel proapoptotic agents

In an effort to develop potent anti-cancer chemopreventive agents, a novel series of bisindole derivatives bearing oxime moiety were synthesized. Structures of all compounds were characterized by NMR and HRMS. Anti-proliferative activities for all of these compounds were investigated by the method of MTT assay on 7 human cancer lines and the normal cell lines (HUVEC). Most of them showed a noteworthy anti-cancer activity in vitro, the half maximal inhibitory concentration (IC50) value is 4.31 μM of 4e against T24. The results from Hoechst 33258 and acridine orange/propidium iodide staining as well as annexinV-FITC assays provided evidence for an apoptotic cell death. The further mechanisms of compound 4e-induced apoptosis in T24 cells demonstrated that compound 4e induced the productions of ROS, and altered anti- and pro-apoptotic proteins, leading to mitochondrial dysfunction and activations of caspase-9 and caspase-3 for causing cell apoptosis. Moreover, the cell cycle analysis and western-blot analysis indicated that compound 4e effectively arrested T24 cells in G1 stage and possibly has an effect on cell cycle regulatory proteins particularly cyclin D1.

Synthesis and biological evaluation of new pyridone-annelated isoindigos as anti-proliferative agents

A selected set of substituted pyridone-annelated isoindigos 3a-f has been synthesized via interaction of 5- and 6-substituted oxindoles 2a-f with 6-ethyl-1,2,9-trioxopyrrolo[3,2-f]quinoline-8-carboxylic acid (1) in acetic acid at reflux. Among these isoindigos, the 5'-chloro and 5'-bromo derivatives 3b and 3d show strong and selective antiproliferative activities against a panel of human hematological and solid tumor cell-lines, but not against noncancerous cells, suggesting their potential use as anticancer agents. In all the tested cell lines, compound 3b was a 25%-50% more potent inhibitor of cell growth than 3d, suggesting the critical role of the substitution at 5'-position of the benzo-ring E. The IC50 values after 48 hours incubation with the 5'-chloro compound 3b were 6.60 µM in K562, 8.21 µM in THP-1, 8.97 µM in HepG2, 11.94 µM in MCF-7 and 14.59 µM in Caco-2 cancer cells, while the IC50 values in noncancerous HEK-293 and L-929 were 30.65 µM and 40.40 µM, respectively. In addition, compound 3b induced higher levels apoptosis in K562 cells than 3d, as determined by annexin V/7-AAD flowcytometry analysis. Therefore, further characterization of the antitproliferative mechanisms of compounds 3b and 3d may provide a novel chemotherapeutic agents.