Identification of novel non-toxic and anti-angiogenic α-fluorinated chalcones as potent colchicine binding site inhibitors

Current scenario of chalcone hybrids with antibreast cancer therapeutic applications

Breast cancer, an epithelial malignant tumor that occurs in the terminal ducts of the breast, is the most common female malignancy. Currently, approximately 70%-80% of breast cancer with early-stage, nonmetastatic disorder is curable, but the emergency of drug resistance often leads to treatment failure. Moreover, advanced breast cancer with distant organ metastases is incurable with the available therapeutics, creating an urgent demand to explore novel antibreast cancer agents. Chalcones, the precursors for flavonoids and isoflavonoids, exhibit promising activity against various breast cancer hallmarks, inclusive of proliferation, angiogenesis, invasion, metastasis, inflammation, stemness, and regulation of cancer epigenetics, representing useful scaffolds for the discovery of novel antibreast cancer chemotherapeutic candidates. In particular, chalcone hybrids could act on two or more different biological targets simultaneously with more efficacy, lower toxicity, and less susceptibility to resistance. Accordingly, there is a huge scope for application of chalcone hybrids to tackle the present difficulties in breast cancer therapy. This review outlines the chalcone hybrids with antibreast cancer potential developed from 2018. The structure-activity relationships as well as mechanisms of action are also discussed to shed light on the development of more effective and multitargeted chalcone candidates.

Indole derivatives targeting colchicine binding site as potential anticancer agents

Microtubules are appealing as intracellular targets for anticancer activity due to their importance in cell division. Three important binding sites are present on the tubulin protein: taxane, vinca, and colchicine binding sites (CBS). Many USFDA-approved drugs such as paclitaxel, ixabepilone, vinblastine, and combretastatin act by altering the dynamics of the microtubules. Additionally, a large number of compounds have been synthesized by medicinal chemists around the globe that target different tubulin binding sites. Although CBS inhibitors have proved their cytotoxic potential, no CBS-targeting drug had been able to reach the market. Several studies have reported design, synthesis, and biological evaluation of indole derivatives as potential anticancer agents. These compounds have been shown to inhibit cancer cell proliferation, induce apoptosis, and disrupt microtubule formation. Moreover, the binding affinity of these compounds to the CBS has been demonstrated using molecular docking studies and competitive binding assays. The present work has reviewed indole derivatives as potential colchicine-binding site inhibitors. The structure-activity relationship studies have revealed the crucial pharmacophoric features required for the potent and selective binding of indole derivatives to the CBS. The development of these compounds with improved efficacy and reduced toxicity could potentially lead to the development of novel and effective cancer therapies.

Chalcones and Gastrointestinal Cancers: Experimental Evidence

Colorectal (CRC) and gastric cancers (GC) are the most common digestive tract cancers with a high incidence rate worldwide. The current treatment including surgery, chemotherapy or radiotherapy has several limitations such as drug toxicity, cancer recurrence or drug resistance and thus it is a great challenge to discover an effective and safe therapy for CRC and GC. In the last decade, numerous phytochemicals and their synthetic analogs have attracted attention due to their anticancer effect and low organ toxicity. Chalcones, plant-derived polyphenols, received marked attention due to their biological activities as well as for relatively easy structural manipulation and synthesis of new chalcone derivatives. In this study, we discuss the mechanisms by which chalcones in both in vitro and in vivo conditions suppress cancer cell proliferation or cancer formation.

Essential Oils of Tagetes minuta and Lavandula coronopifolia from Djibouti: Chemical Composition, Antibacterial Activity and Cytotoxic Activity against Various Human Cancer Cell Lines

The chemical composition of the essential oils of two plants (Tagetes minuta L. and Lavandula coronopifolia L.) harvested from the Day region (in the north of Djibouti) is the subject of this study. The extraction of essential oils was carried out by hydrodistillation, and the average yield was obtained at a rate of approximately 0.25% for Tagetes minuta L. and 0.42% for Lavandula coronopifolia L. The analyses of these essential oils by gas chromatography coupled with mass spectrometry identified 13 compounds in the essential oil of Tagetes minuta L., including dihydrotagetone (20.8%), artemisia (17.9%), (Z)-tagetenone (12.4%), (-)-spathulenol (11.0%) and estragole (9.5%), were obtained as majority compounds, with a percentage of 71.6%. The essential oil of Lavandula coronopifolia L. is characterized by the presence of 42 compounds, including cis-caryophyllene (18.9%), dehydronerolidol (12.8%), isolongifolanone (11.2%), caryophyllene oxide (8.2%), 10-epi-β-eudesmol (7.7%) and humulene (5.1%), were obtained as the majority chemical constituents, with a percentage of 63.9%. The antimicrobial activities of the essential oils at concentrations of 5% were measured against 12 bacterial strains (Gram positive: Staphylococcus aureus (ATCC 29213), Enterococcus faecalis (ATCC 29212), Streptococcus agalactiae (ATCC 27956), Staphylococcus epidermidis and Corynebacterium sp.; Gram Negative: Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 700603), Acinetobacter baumannii (ATCC 19606), Shigella sonnei (ATCC 9290), Salmonella enterica sv. Typhimurium (ATCC 13311) and Enterobacter cloacae), and the results of in vitro experiments showed inhibitory effects against most strains tested except Staphylococcus aureus, Enterococcus faecalis and Streptococcus agalactiae. Additionally, both oils were tested for their ability to selectively kill 13 human cancer cells (K562, A549, HCT116, PC3, U87-MG, MIA-Paca2, HEK293, NCI-N87, RT4, U2OS, A2780, MRC-5 and JIMT-T1), and the results obtained, according to the values of IC50, show the significant activity of two essential oils, particularly on the HCT116 and A2780 lines, which present values between 0.25 µg/mL and 0.45 µg/mL, respectively.

Angiogenesis and anti-leukaemia activity of novel indole derivatives as potent colchicine binding site inhibitors

The screened compound DYT-1 from our in-house library was taken as a lead (inhibiting tubulin polymerisation: IC₅₀=25.6 µM, anti-angiogenesis in Zebrafish: IC₅₀=38.4 µM, anti-proliferation against K562 and Jurkat: IC₅₀=6.2 and 7.9 µM, respectively). Further investigation of medicinal chemistry conditions yielded compound 29e (inhibiting tubulin polymerisation: IC₅₀=4.8 µM and anti-angiogenesis in Zebrafish: IC₅₀=3.6 µM) based on tubulin and zebrafish assays, which displayed noteworthily nanomolar potency against a variety of leukaemia cell lines (IC₅₀= 0.09–1.22 µM), especially K562 cells where apoptosis was induced. Molecular docking, molecular dynamics (MD) simulation, radioligand binding assay and cellular microtubule networks disruption results showed that 29e stably binds to the tubulin colchicine site. 29e significantly inhibited HUVEC tube formation, migration and invasion in vitro. Anti-angiogenesis in vivo was confirmed by zebrafish xenograft. 29e also prominently blocked K562 cell proliferation and metastasis in blood vessels and surrounding tissues of the zebrafish xenograft model. Together with promising physicochemical property and metabolic stability, 29e could be considered an effective anti-angiogenesis and -leukaemia drug candidate that binds to the tubulin colchicine site.