Synthesis and antitumor activity of novel substituted uracil-1'(N)-acetic acid ester derivatives of 20(S)-camptothecins

Novel Coumarin-Nucleobase Hybrids with Potential Anticancer Activity: Synthesis, In Vitro Cell-Based Evaluation, and Molecular Docking

A new series of compounds planned by molecular hybridization of the nucleobases uracil and thymine, or the xanthine theobromine, with coumarins, and linked through 1,2,3-triazole heterocycles were evaluated for their in vitro anticancer activity against the human tumor cell lines: colon carcinoma (HCT116), laryngeal tumor cells (Hep-2), and lung carcinoma cells (A549). The hybrid compound 9a exhibited better activity in the series, showing an IC50 of 24.19 ± 1.39 μM against the HCT116 cells, with a selectivity index (SI) of 6, when compared to the cytotoxicity against the non-tumor cell line HaCat. The in silico search for pharmacological targets was achieved through molecular docking studies on all active compounds, which suggested that the synthesized compounds possess a high affinity to the Topoisomerase 1-DNA complex, supporting their antitumor activity. The in silico toxicity prediction studies suggest that the compounds present a low risk of causing theoretical mutagenic and tumorigenic effects. These findings indicate that molecular hybridization from natural derivative molecules is an interesting approach to seek new antitumor candidates.

Polymeric micelles paving the Way: Recent breakthroughs in camptothecin delivery for enhanced chemotherapy

Camptothecin, a natural alkaloid, was first isolated from the bark and stem of the Camptotheca acuminate tree in China. It, along with its analogs, has demonstrated potent anti-cancer activity in preclinical studies, particularly against solid tumors such as lung, breast, ovarian, and colon cancer. Despite its promising anti-cancer activity, the application of camptothecin is limited due to its poor solubility, toxicity, and limited biodistribution. Nanotechnology-based drug delivery systems have been used to overcome limited bioavailability and ensure greater biodistribution after administration. Additionally, various drug delivery systems, particularly polymeric micelles, have been investigated to enhance the solubility, stability, and efficacy of camptothecin. Polymeric micelles offer a promising approach for the delivery of camptothecin. Polymeric micelles possess a core-shell structure, with a typical hydrophobic core, which exhibits a high capacity to incorporate hydrophobic drugs. The structure of polymeric micelles can be engineered to have a high drug loading capacity, thereby enabling them to carry a large amount of hydrophobic drug within their core. The shell portion of polymeric micelles is composed of hydrophilic polymers Furthermore, the hydrophilic segment of polymeric micelles plays an important role in protecting against the reticuloendothelial system (RES). This review provides a discussion on recent research and developments in the delivery of camptothecin using polymeric micelles for the treatment of cancers.

20-esterification of 5-spiro CPT and their anticancer activity in vitro

20-ester of 5-spirocycle campthothecin derivatives were successfully constructed and synthesised by Steglich esterification in a moderate yield. These derivatives showed a better solubility. Compared to parent compound, most of these 20-ester-5-spirocycle campthothecin derivatives (besides 3g) showed a better inhibition activity against HepG2 cell line.

Facile synthesis and cytotoxicity of substituted uracil-1'(N)-acetic acid and 4-pyridone-1'(N)-acetic acid esters of 20(S)-camptothecins

A series of novel substituted uracil-1'(N)-acetic acid esters (5-9) and 4-pyridone-1'(N)-acetic acid esters (10-11) of 20(S)-camptothecins (CPTs) have been synthesized by the acylation method. All of these new esters were assayed for in vitro cytotoxicity against five human cancer cell lines A549, Bel7402, BGC-823, HCT-8 and A2780. The in vitro bioassay results showed that all the synthesized compounds 5-11 had cytotoxities that were higher than TPT and comparable to CPT on these five tumor cell lines, some of them even showed comparable or superior cytotoxic activity to CPT. The in vitro data exhibited the cytotoxicity of the ester depended on that of its parent compound. The ester 5, 6, 8, 10, 11 even possessed the cytotoxity activity comparable to or even a little better than CPT on A549, HCT-8 and A2780. The compound 11 had the same level of cytoxity on Bel7402 as that of CPT. Here the synthesis and the in vitro antitumor evaluation of a series of novel 20-O-linked substituted uracil-1'(N)-acetic acid and 4-pyridone-1'(N)-acetic acid esters derivatives of CPTs are reported.

Synthesis and biological evaluation of novel salicylidene uracils: Cytotoxic activity on human cancer cell lines and inhibitory action on enzymatic activity

A series of salicylidene uracil (1-18) derived from 5-aminouracil and substituted salicylaldehydes were analyzed for cytotoxic activity and enzyme inhibitory potency. Nine out of eighteen derivatives (6-8, 10, 12-15, 18) are novel molecules synthesized for the first time in this work, and other derivatives were previously synthesized by our group. The compounds were characterized by Proton nuclear magnetic resonance, carbon nuclear magnetic resonance, fourier transform infrared spectroscopy, and elemental analysis. All compounds were tested for their in vitro cytotoxicity against PC-3 (human prostate adenocarcinoma), A549 (human alveolar adenocarcinoma), and SHSY-5Y (human neuroblastoma) cancer cell lines and the nontumorigenic HEK293 (human embryonic kidney cells) cell line. The 3,5-di-tert-butylsalicylaldehyde derived compound (8) was toxic to PC-3 human prostate adenocarcinoma cells, showing a promising IC50 value at 7.05 ± 0.76 μM. The present study also aimed to evaluate the inhibitory effects of the compounds against several key enzymes, namely carbonic anhydrase I and II (CA I and CA II), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and glutathione reductase (GR), which are implicated in various global disorders, such as Alzheimer's disease, epilepsy, cancer, malaria, diabetes, and glaucoma. The inhibitory profiles of the tested compounds were assessed by determining their Ki values, which ranged from 2.96 to 9.24 nM for AChE, 3.78 to 12.57 nM for BChE, 8.42 to 25.74 nM for CA I, 7.24 to 19.74 nM for CA II, and 0.541 to 1.124 μM for GR. Molecular docking studies were also performed for all compounds. Most derivatives exhibited much more effective inhibitory action compared with clinically used standards. Thus, our findings indicate that the salicylidene derivatives presented in this study are promising drug candidates that need further evaluation.

Phytochemical Analysis of Nothapodytes tomentosa and Distribution and Content of Camptothecin and its Analogues in Four Plants

Camptothecin (CPT) and its derivatives have attracted worldwide attention because of their notable anticancer activity. However, the growing demand for CPT in the global pharmaceutical industry has caused a severe shortage of CPT-producing plant resources. In this study, phytochemical analysis of Nothapodytes tomentosa results in the isolation and identification of CPT (13: ) and 16 analogues (1:  - 12, 14:  - 17: ), including a new (1: ) and five known (9, 10, 12, 15: , and 17: ) CPT analogues with an open E-ring. In view of the potential anticancer activity of CPT analogues with an open E-ring, the fragmentation pathways and mass spectra profiles of these six CPT analogues (1, 9, 10, 12, 15: , and 17: ) are investigated, providing a reference for the rapid detection of these compounds in other plants. Furthermore, based on the fragmentation patterns of CPT (13: ) and known analogues (2:  - 8, 11, 14, 16, 18:  - 26: ), the distribution and content of these compounds in different tissues of N. tomentosa, N. nimmoniana, Camptotheca acuminata, and Ophiorrhiza japonica are further studied. Our findings not only provide an alternative plant resource for further expanding the development and utilization of CPT and its analogues, but also lay a foundation for improving the utilization of known CPT-producing plant resources.

A novel camptothecin derivative, ZBH-01, exhibits superior antitumor efficacy than irinotecan by regulating the cell cycle

BACKGROUND

Irinotecan (CPT-11) is a classic chemotherapeutic agent that plays an important role in the clinical treatment of metastatic colon cancer and other malignant tumors. We previously designed a series of novel irinotecan derivatives. In this study, we select one representative, ZBH-01, to investigate its sophisticated antitumor mechanism in colon tumor cells.

METHODS

The cytotoxic activity of ZBH-01 on colon cancer cells was evaluate by MTT or Cell Counting Kit-8 (CCK8) assay, 3D and xenograft model. The inhibitory effect of ZBH-01 on TOP1 was detected by DNA relaxation assay and Immuno Complex of Ezyme (ICE) bioassay. The molecular mechanism of ZBH-01 was explored by Next-Generation Sequencing (NGS), bioinformatics analyses, flow cytometry, qRT-PCR, and western blot etc. RESULTS: ZBH-01 can induce obvious DNA damage and has superior antitumor activity against colon cancer cells compared to CPT-11 and SN38 (7-Ethyl-10-hydroxy camptothecin, the in vivo active form of CPT-11) both in vivo and in vitro. Its inhibitory effect on topoisomerase I (TOP1) was also comparable with these two control drugs. There are a much larger number of 842 downregulated and 927 upregulated mRNAs in ZBH-01 treatment group than that in the controls. The most significantly enriched KEGG pathways for these dysregulated mRNAs were DNA replication, the p53 signaling pathway, and the cell cycle. After constructing a protein-protein interaction (PPI) network and screening out a prominent cluster, 14 involved in the cell cycle process was identified. Consistently, ZBH-01 induced G0/G1 phase arrest in colon cancer cells, while CPT-11/SN38 caused S phase arrest. The initiation of apoptosis by ZBH-01 was also superior to CPT-11/SN38, followed by the increased expression of Bax, active caspase 3, and cleaved-PARP, and decreased expression of Bcl-2. Additionally, CCNA2 (cyclin A2), CDK2 (cyclin-dependent kinase 2), and MYBL2 (MYB proto-oncogene like 2) might be involved in the G0/G1 cell cycle arrest induced by ZBH-01.

CONCLUSIONS

ZBH-01 can be an antitumor candidate drug for preclinical study in the future.

Design and synthesis of uracil/thiouracil based quinoline scaffolds as topoisomerases I/II inhibitors for chemotherapy: A new hybrid navigator with DFT calculation

In this work, a novel promising hybrid mode of uracil/thiouracil based quinoline pharmacophore i.e. 5a-f was rationalized and synthesized based on rigidification and lipophilic principles, and following the reported pharmacophoric features of camptothecin & doxorubicin. Concurrently, a non-rigid mode pharmacophore i.e. 7a-f was also designed and synthesized. The anti-proliferative activity of the compounds was assessed against three different cancer cell lines, namely A549 lung cancer, MCF-7 breast adenocarcinoma, and HepG-2 hepatic carcinoma. Further, promising candidates were evaluated against A549, and MCF-7 and for their ability to inhibit topoisomerases I &II. Compound 5f was observed to be the most active congener, displaying the highest cell inhibition of 84.4% for topoisomerase I and 92%, for topoisomerase II at a concentration of 100 µM. When its cytotoxicity was evaluated against A549 cells, 5f arrested the cell cycle at the S phase and increased the apoptosis ratio by 46.31%. DFT calculation of 5f showed higher dipole moment and greater negative energy values (-247531.510 kcal/mol) with positive & negative poles, and better stability reflection. Furthermore, molecular docking of 5f to both enzymes showed good agreement with the biological assessment. This study has given insight for further consideration of the highly promising hybrid 5f.

A novel irinotecan derivative ZBH-1207 with different anti-tumor mechanism from CPT-11 against colon cancer cells

PURPOSE

Irinotecan (CPT-11) is a camptothecin derivative whose potent anti-tumor activity depends on the rapid formation of an in vivo active metabolite, SN38 (7-ethyl-10-hydroxycamptothecin). CPT-11 combine with other agents are often the treatment of choice for patients with advanced or metastatic colorectal cancer (CRC). This study evaluates the cytotoxic mechanism of a novel CPT-11 derivative, ZBH-1207 in CRC cells in vitro.

METHODS

The anti-proliferation effect of ZBH-1207 on tumor cells was assessed by MTT assay. The inhibition of TOP1, the alteration of cell cycle and apoptosis, and the expression of caspase-3 and PARP in CRC cells induced by ZBH-1207 were detected by DNA relaxation assay, flow cytometry, and Western blot, respectively.

RESULTS

ZBH-1207 significantly inhibits the proliferation of seven tumor cell lines and retains the activity of TOP1 as compared with CPT-11. Treatment with ZBH-1207 results in more apparent cell cycle arrests and apoptosis of CRC cells than that of CPT-11 and SN38. Accordingly, up-regulation of active caspase-3 and PARP expression were relatively higher in ZBH-1207 group than that in CPT-11 and SN38 group.

CONCLUSION

ZBH-1207 has higher cytotoxicity than CPT-11/SN38 in CRC cells. Its molecular mechanism involves apoptosis signaling pathway.

Camptothecin's journey from discovery to WHO Essential Medicine: Fifty years of promise

Nature represents a rich source of compounds used for the treatment of many diseases. Camptothecin (CPT), isolated from the bark of Camptotheca acuminata, is a cytotoxic alkaloid that attenuates cancer cell replication by inhibiting DNA topoisomerase 1. Despite its promising and wide spectrum antiproliferative activity, its use is limited due to low solubility, instability, acquired tumour cell resistance, and remarkable toxicity. This has led to the development of numerous CPT analogues with improved pharmacodynamic and pharmacokinetic profiles. Three natural product-inspired drugs, namely, topotecan, irinotecan, and belotecan, are clinically approved and prescribed drugs for the treatment of several types of cancer, whereas other derivatives are in clinical trials. In this review, which covers literature from 2015 to 2020, we aim to provide a comprehensive overview and describe efforts that led to the development of a variety of CPT analogues. These efforts have led to the discovery of potent, first-in-class chemotherapeutic agents inspired by CPT. In addition, the mechanism of action, SAR studies, and recent advances of novel CPT drug delivery systems and antibody drug conjugates are discussed.

Quinoline anticancer agents active on DNA and DNA-interacting proteins: From classical to emerging therapeutic targets

Quinoline is one of the most important and versatile nitrogen heterocycles embodied in several biologically active molecules. Within the numerous quinolines developed as antiproliferative agents, this review is focused on compounds interfering with DNA structure or with proteins/enzymes involved in the regulation of double helix functional processes. In this light, a special focus is given to the quinoline compounds, acting with classical/well-known mechanisms of action (DNA intercalators or Topoisomerase inhibitors). In particular, the quinoline drugs amsacrine and camptothecin (CPT) have been studied as key lead compounds for the development of new agents with improved PK and tolerability properties. Moreover, notable attention has been paid to the quinoline molecules, which are able to interfere with emerging targets involved in cancer progression, as G-quadruplexes or the epigenetic ones (e.g.: histone deacetylase, DNA and histones methyltransferase). The antiproliferative and the enzymatic inhibition data of the reviewed compounds have been analyzed. Furthermore, concerning the SAR (structure-activity relationship) aspects, the most recurrent ligand-protein interactions are summarized, underling the structural requirements for each kind of mechanism of action.

Design, synthesis and in vivo anticancer activity of novel parthenolide and micheliolide derivatives as NF-κB and STAT3 inhibitors

Parthenolide and micheliolide have attracted great attention in anticancer research due to their unique activities. In this study, thirteen parthenolide derivatives and twenty-three micheliolide derivatives were synthesized. Most synthesized compounds showed higher cytotoxicity than parthenolide or micheliolide. The in vivo anticancer activity of several representative compounds was evaluated in mice. One micheliolide derivative, 9-oxomicheliolide (43), showed promising in vivo antitumor activity compared with clinical drugs cyclophosphamide or temozolomide. Compound 43 was particularly effective against glioblastoma, with its tumor inhibition rate in mice comparable to the drug temozolomide. The discovery of compound 43 also demonstrates the feasibility of developing anticancer micheliolide derivatives by modification at C-9 position. Anticancer mechanism studies revealed that 9-oxomicheliolide exhibited inhibition effect against NF-κB and STAT3 signaling pathways, as well as induction effects of cell apoptosis. It is postulated that 9-oxomicheliolide is likely to be a modulator of the immune system, which regulates the anticancer immune responses.

Antitumour properties based on the self-assembly of camptothecin and carbamoylmannose conjugates

Camptothecin (CPT) and its analogues show potent antitumour activity. However, poor water solubility and severe side effects have restricted their applications in clinical practice. In this paper, a novel self-assembly based on camptothecin and carbamoylmannose conjugates (CPT-Man) was constructed. The self-assembly increased the water solubility of camptothecin to 0.64 mg/ml and antitumour activity. Moreover, CPT-Man could induce obvious cancer cell apoptosis. This work provides a new approach for exploring carbohydrate-modified antitumour properties by self-assembled CPT drugs.

Synthetic Optimization of Ellipticine and Antitumor Activity of Novel Hexacyclic Derivatives of Ellipticine

Background:

For decades, a great deal of research work has been done to synthesize ellipticine and its derivatives because of their potential antitumor properties and anti-HIV activities. However, the resonance structures in different media, a low level of solubility at physiological pH and systemic toxicity have prevented the use of ellipticine as a therapeutic agent. Besides, the low yield and complex steps of ellipticine synthesis limit its application.

Methods:

A high-yield synthetic procedure of ellipticine has been optimized, and the total yield was up to 50% without silica gel column chromatography. Novel hexacyclic ellipticine derivatives were synthesized by coupling ellipticine with o-aminobenzoic acid. Their cytotoxicities against HCT116, MGC803, HT29 and MCF-7 tumor cells were evaluated.

Results:

The synthesis process of ellipticine was optimized, and the total yield of the synthetic route was increased to 50% through several operation steps optimization. Fourteen ellipticine hexacyclic derivatives were synthesized. The synthetic compounds were screened for anti-tumor activity in vivo and in vitro, and some of the derivatives had good anti-tumor activity.

Conclusion:

Compared with ellipticine, the compound 1l showed higher antitumor activity and better tolerance to tumor models. The compound 1l treatment increased the percentage of late apoptotic cells from 3.1% (DMSO) to 21.6% (20.0 μM) in NCI-H460 cells. It also was observed the effect of 1l on G2 phase arrest was similar as that of ellipticine. The mechanism of action indicated compound 1l could be a topoisomerase IIα poison. These studies provided the basis for the pharmacodynamics and toxicology of ellipticine, and further clarifies the structureactivity relationship of antitumor activity of ellipticine.

Design, Synthesis and Biological Evaluation of Camptothecin Conjugated with NSAIDs as Novel Dual-actin Antitumor Agents

Objective:

The single-agent therapy was unable to provide an effective control of the malignant process, a well-established strategy to improve the efficacy of antitumor therapy is the rational design of drug combinations aimed at achieving synergistic effects.

Objective:

The objective of this study is generating the new potential anticancer agents with synergistic activity. Owing to the unique mechanism of action of Camptothecin (CPT), it has shown abroad spectrum of anti-cancer activity against human malignancies, and growing evidence revealed that Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) reduce the risk of different kinds of cancers. So four CPT-NSAIDs conjugates were synthesized and evaluated.

Methods:

In this study, a series of novel CPT - NSAIDs derivatives were synthesized by esterification. These new compounds were evaluated for in vitro antitumor activity against tumor cell lines A549, Hela, HepG2, HCT116 by MTT assay. To probe the required stabilities as prodrugs, stability tests were studied in human plasma. To further evaluate the stability of Ketoprofen-CPT in vivo, the female SD rats were used to determine the pharmacokinetics following a single oral dose.

Results:

In vitro results showed that Ketoprofen-CPT and Naproxen-CPT conjugates possessed nice efficacy. In a molecular docking model, the two conjugates interacted with Topo I-DNA through hydrogen bonds, <pi>-<pi> stacking and so on.In human plasma results showed that the prodrug was converted to ketoprofen and another compound. The female SD rats were used to determine the pharmacokinetics following a single oral dose, the half-life (t1/2) of Ketoprofen-CPT was approximately 12 h which was much longer than that of CPT.

Conclusion:

Good activity was noted for some compounds will be helpful for the design of dualaction agents with most promising anti-cancer activity.

Synthesis, antitumor activity and pharmacokinetic study of 10-propionyloxy camptothecin in rats

In the present study, a 10-position modified of camptothecin, 10-propionyloxy camptothecin (PCPT) was esterified from 10-hydroxcamptothecin (HCPT), which could metabolize to HCPT in vivo. PCPT displayed a relatively stronger antitumor activity in vitro and in vivo. Thereafter a simple, sensitive and rapid HPLC method coupled with a fluorescence detector was developed and validated for the assay of PCPT and its active metabolite HCPT in rat plasma. The method was validated for accuracy, precision, linearity, selectivity and recovery. The validated method was successfully applied to the pharmacokinetic study of PCPT in rats after intravenous administration. The results showed that PCPT could be mainly converted to HCPT in plasma with the AUC_0-∞ value of 3.69 ± 4.44 and 311.16 ± 188.81 ng h/mL for PCPT and HCPT, respectively.