A Novel Class of N-Sulfonyl and N-Sulfamoyl Noscapine Derivatives that Promote Mitotic Arrest in Cancer Cells

Discovery of novel and highly potent anticancer agents enabled by selenium scanning of noscapine

Herein, the structural modification of noscapine via an elegant selenium scanning strategy has been demonstrated, which enables the production of three classes of novel seleno-containing noscapinoids, namely 6', 7', and 9'-seleno-substituted noscapines. Among them, 9'-seleno-substituted noscapines exhibited superior in vitro anti-proliferative activity, and 9'-cycloheptylselenomethyl-noscapine 17a16 with a large hydrophobic cycloheptyl group showed the most potent activity and good selectivity. Unlike most of the reported noscapinoids that induce G2/M phase arrest by targeting microtubules, 17a16 exhibited a distinct ability to induce S-phase arrest and displayed superior potency in inducing apoptosis, which attribute to the activation of two parallel checkpoint pathways orchestrating DNA damage response, including DNA-PKcs-dependent p53 stabilization and ATR-Chk1 axis activation. Dissecting the upstream mechanism revealed that 17a16 targets mitochondria and induces mitochondrial dysfunction. This study elucidates the interplay of mitochondrial stress, DNA damage response, p53 and ATR-Chk1 checkpoint activation in mediating the anticancer effects of 17a16. Furthermore, 17a16 treatment significantly suppressed tumor growth in p53-deficient JeKo-1 subcutaneous xenograft model in vivo, without inducing systemic toxicity. Overall, our findings highlight 17a16 as a promising lead compound in cancer therapy and demonstrate the potential of selenium scanning as a valuable strategy for anticancer drug discovery.

Discovery of N-Trifluoromethylated Noscapines as Novel and Potent Agents for the Treatment of Glioblastoma

The search for new and effective chemotherapeutic agents for the treatment of glioblastoma (GBM) represents an unmet need in drug discovery. Herein, a class of novel N-trifluoromethylated noscapines has been disclosed. Among them, 9'-bromo-N-trifluoromethyl noscapine 15c displayed superior in vitro anti-GBM potency. Unexpectedly, in contrast with the general N-trifluoromethyl amines, these compounds exhibited good hydrolytic stability and further investigation of this distinct stability revealed a novel strategy for the structure modification of tetrahydroisoquinoline alkaloids, where N-methyl could be bioisosterically replaced with trifluoromethyl. Furthermore, 15c showed excellent BBB permeability and good in vivo anti-GBM activity and could efficiently suppress the migration of GBM cells, while no apparent toxicity was observed, thus representing an attractive lead for further drug discovery. Further mechanistic studies revealed that 15c exhibited an ability to induce G2/M-phase arrest in GBM cells associated with the disruption of tubulin polymerization, which is consistent with the mechanism of action of noscapine.

Synthesis and modification of noscapine derivatives as promising future anticancer agents

Noscapine, a tetrahydroisoquinoline alkaloid, was first isolated from Papaver somniferum and identified by Rabiquet in 1817. It has been used as an anti-tussive agent since the mid-1950 s. After the discovery of its anti-mitotic potential, it was into the limelight once again. Due to its low toxicity, high bioactivity and oral administration, It was regarded as a formidable framework for subsequent modification and advancement in the pursuit of innovative chemotherapeutic agents. Up to now, the rational derivatives of the noscapine have been designed and the biological activities of these analogues have been extensively investigated. This review provides a comprehensive examination of the chemical characteristics of noscapine and its semi-synthetic derivatives up to the present, encompassing a concise investigation into the biological properties of these compounds and additionally a discussion about biosynthesis and total synthesis of noscapine is also provided. In summary, our aim is to contribute to a more thorough comprehension of this structure. It can be asserted that a promising future lies ahead for noscapine and its engineered derivatives as noteworthy candidates for pharmaceutical drugs.

Synthesis and Biological Evaluation of Phthalideisoquinoline Derivatives

A photo and Cu-mediated radical-radical approach enabling the one-step synthesis of the phthalideisoquinoline skeleton has been reported. Under mild reaction conditions, a series of N-aryl phthalideisoquinolines containing various substituents were synthesized in moderate to good yields. Bioactivity data demonstrated that a new compound 4x can efficiently inhibit the growth of multiple tumor cell lines with enhancements of more than 10-fold by significantly increasing G₂/M arrest compared with noscapine.

1,3-Benzodioxole-Modified Noscapine Analogues: Synthesis, Antiproliferative Activity, and Tubulin-Bound Structure

Since the revelation of noscapine's weak anti-mitotic activity, extensive research has been conducted over the past two decades, with the goal of discovering noscapine derivatives with improved potency. To date, noscapine has been explored at the 1, 7, 6', and 9'-positions, though the 1,3-benzodioxole motif in the noscapine scaffold that remains unexplored. The present investigation describes the design, synthesis and pharmacological evaluation of noscapine analogues consisting of modifications to the 1,3-benzodioxole moiety. This includes expansion of the dioxolane ring and inclusion of metabolically robust deuterium and fluorine atoms. Favourable structural modifications were subsequently incorporated into multi-functionalised noscapine derivatives that also possessed modifications previously shown to promote anti-proliferative activity in the 1-, 6'- and 9'-positions. Our research efforts afforded the deuterated noscapine derivative 14 e and the dioxino-containing analogue 20 as potent cytotoxic agents with EC₅₀ values of 1.50 and 0.73 μM, respectively, against breast cancer (MCF-7) cells. Compound 20 also exhibited EC₅₀ values of <2 μM against melanoma, non-small cell lung carcinoma, and cancers of the brain, kidney and breast in an NCI screen. Furthermore, compounds 14 e and 20 inhibit tubulin polymerisation and are not vulnerable to the overexpression of resistance conferring P-gp efflux pumps in drug-resistant breast cancer cells (NCI^ADR/RES ). We also conducted X-ray crystallography studies that yielded the high-resolution structure of 14 e bound to tubulin. Our structural analysis revealed the key interactions between this noscapinoid and tubulin and will assist with the future design of noscapine derivatives with improved properties.

Bioengineering of Anti-Inflammatory Natural Products

Inflammatory processes occur as a generic response of the immune system and can be triggered by various factors, such as infection with pathogenic microorganisms or damaged tissue. Due to the complexity of the inflammation process and its role in common diseases like asthma, cancer, skin disorders or Alzheimer's disease, anti-inflammatory drugs are of high pharmaceutical interest. Nature is a rich source for compounds with anti-inflammatory properties. Several studies have focused on the structural optimization of natural products to improve their pharmacological properties. As derivatization through total synthesis is often laborious with low yields and limited stereoselectivity, the use of biosynthetic, enzyme-driven reactions is an attractive alternative for synthesizing and modifying complex bioactive molecules. In this minireview, we present an outline of the biotechnological methods used to derivatize anti-inflammatory natural products, including precursor-directed biosynthesis, mutasynthesis, combinatorial biosynthesis, as well as whole-cell and in vitro biotransformation.

Design, Synthesis and Evaluation of 2,4-Diaminoquinazoline Derivatives as Potential Tubulin Polymerization Inhibitors

Microtubules are highly dynamic polymers composed of α- and β-tubulin proteins that have been shown to be potential therapeutic targets for the development of anticancer drugs. Currently, a wide variety of chemically diverse agents that bind to β-tubulin have been reported. Nocodazole (NZ) and colchicine (COL) are well-known tubulin-depolymerizing agents that have close binding sites in the β-tubulin. In this study, we designed and synthesized a set of nine 2,4-diaminoquinazoline derivatives that could occupy both NZ and COL binding sites. The synthesized compounds were evaluated for their antiproliferative activities against five cancer cell lines (PC-3, HCT-15, MCF-7, MDA-MB-231, and SK-LU-1), a noncancerous one (COS-7), and peripheral blood mononuclear cells (PBMC). The effect of compounds 4 e and 4 i on tubulin organization and polymerization was analyzed on the SK-LU-1 cell line by indirect immunofluorescence, western blotting, and tubulin polymerization assays. Our results demonstrated that both compounds exert their antiproliferative activity by inhibiting tubulin polymerization. Finally, a possible binding pose of 4 i in the NZ/COL binding site was determined by using molecular docking and molecular dynamics (MD) approaches. To our knowledge, this is the first report of non-N-substituted 2,4-diaminoquinazoline derivatives with the ability to inhibit tubulin polymerization.

Cytochrome P450-mediated N-demethylation of noscapine by whole-cell biotransformation: process limitations and strategies for optimisation

Cytochrome P450 enzymes catalyse reactions of significant industrial interest but are underutilised in large-scale bioprocesses due to enzyme stability, cofactor requirements and the poor aqueous solubility and microbial toxicity of typical substrates and products. In this work, we investigate the potential for preparative-scale N-demethylation of the opium poppy alkaloid noscapine by a P450_BM3 (CYP102A1) mutant enzyme in a whole-cell biotransformation system. We identify and address several common limitations of whole-cell P450 biotransformations using this model N-demethylation process. Mass transfer into Escherichia coli cells was found to be a major limitation of biotransformation rate and an alternative Gram-positive expression host Bacillus megaterium provided a 25-fold improvement in specific initial rate. Two methods were investigated to address poor substrate solubility. First, a biphasic biotransformation system was developed by systematic selection of potentially biocompatible solvents and in silico solubility modelling using Hansen solubility parameters. The best-performing biphasic system gave a 2.3-fold improvement in final product titre compared to a single-phase system but had slower initial rates of biotransformation due to low substrate concentration in the aqueous phase. The second strategy aimed to improve aqueous substrate solubility using cyclodextrin and hydrophilic polymers. This approach provided a fivefold improvement in initial biotransformation rate and allowed a sixfold increase in final product concentration. Enzyme stability and cell viability were identified as the next parameters requiring optimisation to improve productivity. The approaches used are also applicable to the development of other pharmaceutical P450-mediated biotransformations.