Nitric oxide releasing acridone carboxamide derivatives as reverters of doxorubicin resistance in MCF7/Dx cancer cells

Novel Glu-based pyrazolo[3,4-d]pyrimidine analogues: design, synthesis and biological evaluation as DHFR and TS dual inhibitors

A novel series of multifunctional pyrazolo[3,4-d]pyrimidine-based glutamate analogs (6a-l and 7a,b) have been designed and synthesized as antifolate anticancer agents. Among the tested compounds, 6i exhibited the most potent anti-proliferative activity towards NSCLC, CNS, Ovarian, Prostate, Colon, Melanoma, Breast, and Renal cancers with good to weak cytostatic activity and non-lethal actions. 6i demonstrated higher selectivity for cancer than normal cells. 6i could significantly increase the accumulation of S-phase cells during the cell cycle distribution of cancer cells with high potency in the induction of apoptosis. The results unveiled that 6i probably acts through dual inhibition of DHFR and TS enzymes (IC₅₀ = 2.41 and 8.88 µM, correspondingly). Docking studies of 6i displayed that N1-p-bromophenyl and C3-Methyl groups participate in substantial hydrophobic interactions. The drug-likeness features inferred that 6i met the acceptance criteria of Pfizer. Taking together, 6i could be a promising prototype for further optimization as an effective anticancer drug.

Evaluation of N 10 -substituted acridone-based derivatives as AKT inhibitors against breast cancer cells: in vitro and molecular docking studies

A series of N 10 -substituted acridone-2-carboxamide derivatives were synthesized and evaluated for their potent anti-cancer agents targeting AKT kinase. In vitro cytotoxicity activity of the target compounds was tested against breast cancer cell lines (MCF-7 and MDA-MB-231). Among the tested compounds, four compounds (7f, 8d, 8e, and 8f) exhibited promising anti-cancer activity against both cancer cell lines. Notably, compound 8f demonstrated the highest activity against MCF-7 and MDA-MB-231 at IC50 values of 4.72 and 5.53 μM, respectively. In vitro AKT kinase activity revealed that compounds 7f and 8f were the most potent AKT inhibitors with IC50 values of 5.38 and 6.90 μM, respectively. In addition, the quantitative ELISA method of testing confirmed that compound 8f effectively inhibited cell proliferation by suppressing the activation of p-AKT Ser473. Furthermore, molecular docking studies revealed that compound 8f can bind well to the active site of the AKT enzyme. The in silico ADME studies suggested that all synthesized molecules showed good oral bioavailability with a low-toxicity profile and can be used for further optimization as AKT kinase inhibitors in the treatment of breast cancer.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03524-z.

A comprehensive review on acridone based derivatives as future anti-cancer agents and their structure activity relationships

The development of drug resistance and severe side-effects has reduced the clinical efficacy of the existing anti-cancer drugs available in the market. Thus, there is always a constant need to develop newer anti-cancer drugs with minimal adverse effects. Researchers all over the world have been focusing on various alternative strategies to discover novel, potent, and target specific molecules for cancer therapy. In this direction, several heterocyclic compounds are being explored but amongst them one promising heterocycle is acridone which has attracted the attention of medicinal chemists and gained huge biological importance as acridones are found to act on different therapeutically proven molecular targets, overcome ABC transporters mediated drug resistance and DNA intercalation in cancer cells. Some of these acridone derivatives have reached clinical studies as these heterocycles have shown huge potential in cancer therapeutics and imaging. Here, the authors have attempted to compile and make some recommendations of acridone based derivatives concerning their cancer biological targets and in vitro-cytotoxicity based on drug design and novelty to increase their therapeutic potential. This review also provides some important insights on the design, receptor targeting and future directions for the development of acridones as possible clinically effective anti-cancer agents.

Design, Synthesis, and Biological Evaluation of a Novel VEGFR-2 Inhibitor Based on a 1,2,5-Oxadiazole-2-Oxide Scaffold with MAPK Signaling Pathway Inhibition

Over the past few decades, the development of broad-spectrum anticancer agents with anti-angiogenic activity has witnessed considerable progress. In this study, a new series of pyrazolo[3,4-d]pyrimidines based on a phenylfuroxan scaffold were designed, synthesized, and evaluated, in terms of their anticancer activities. NCI-60 cell one-dose screening revealed that compounds 12a–c and 14a had the best MGI%, among the tested compounds. The target fluorinated compound 12b, as the most active one, showed better anticancer activity compared to the reference drug sorafenib, with IC₅₀ values of 11.5, 11.6, and 13 µM against the HepG-2, A2780CP, and MDA-MB-231 cell lines, respectively. Furthermore, compound 12b (IC₅₀ = 0.092 µM) had VEGFR-2-inhibitory activity comparable to that of the standard inhibitor sorafenib (IC₅₀ = 0.049 µM). Furthermore, the ability of compound 12b in modulating MAPK signaling pathways was investigated. It was found to decrease the level of total ERK and its phosphorylated form, as well as leading to the down-regulation of metalloproteinase MMP-9 and the over-expression of p21 and p27, thus leading to subG1 cell-cycle arrest and, thus, the induction of apoptosis. Additionally, compound 12b decreased the rate of wound healing in the absence of serum, in comparison to DMSO-treated cells, providing a significant impact on metastasis inhibition. The quantitative RT-PCR results for E-cadherin and N-cadherin showed lower expression of the neuronal N-cadherin and increased expression of epithelial E-cadherin, indicating the ability of 12b to suppress metastasis. Furthermore, 12b-treated HepG2 cells expressed a low level of anti-apoptotic BCL-2 and over-expressed proapoptotic Bax genes, respectively. Using the DAF-FM DA fluorescence probe, compound 12b produced NO intracellularly as efficiently as the reference drug JS-K. In silico molecular docking studies showed a structural similarity through an overlay of 12b with sorafenib. Interestingly, the drug-likeness properties of compound 12b met the expectations of Pfizer’s rule for the design of new drug candidates. Therefore, this study presents a novel anticancer lead compound that is worthy of further investigation and activity improvement.

Cross-linking of S-nitrosothiolated AIEgens inside cancer cells to monitor NO release and reverse chemo-resistance

Nitric oxide (NO)-releasing platforms have been demonstrated as promising approaches for the reversal of multidrug resistance (MDR) in cancer cells due to the suppression of P-glycoprotein (P-gp). However, the non-specific systemic release of NO and difficulty in estimating the precise NO amount in target sites hindered their translational applications. Traditional bioimaging techniques which are responsive to NO molecules cannot distinguish between exogenous and endogenous NO. Herein we introduce S-nitrosothiol-functionalized tetraphenylethene (TPE-RSNO) to specifically monitor exogenous NO release and synergistically reverse MDR. TPE-RSNO can specifically respond to NO release and visualize NO delivery with fluorescence in living cells. Moreover, the elevated reactive oxygen species (ROS) in cancer cells triggered rapid NO release to reduce P-gp and thus synergistically increase the therapeutic effect of doxorubicin (DOX).

Multifunctional Isosteric Pyridine Analogs-Based 2-Aminothiazole: Design, Synthesis, and Potential Phosphodiesterase-5 Inhibitory Activity

The elaboration of new small molecules that target phosphodiesterase enzymes (PDEs), especially those of type 5 (PDE5), is an interesting and emerging topic nowadays. A new series of heterocycle-based aminothiazoles were designed and synthesized from the key intermediate, 3-oxo-N-(thiazol-2-yl)butanamide (a PDE5 inhibitor that retains its amidic function), as an essential pharmacophoric moiety. The PDE5 inhibitors prevent the degradation of cyclic guanosine monophosphate, thereby causing severe hypotension as a marked side effect. Hence, an in vivo testing of the target compounds was conducted to verify its relation with arterial blood pressure. Utilizing sildenafil as the reference drug, Compounds 5, 10a, and 11b achieved 100% inhibitions of PDE5 without significantly lowering the mean arterial blood pressures (115.95 ± 2.91, 110.3 ± 2.84, and 78.3 ± 2.57, respectively). The molecular docking study revealed that the tested compounds exhibited docking poses that were similar to that of sildenafil (exploiting the amide functionality that interacted with GLN:817:A). The molecular shape and electrostatic similarity revealed a comparable physically achievable electrostatic potential with the reference drug, sildenafil. Therefore, these concomitant results revealed that the tested compounds exerted sildenafil-like inhibitory effects (although without its known drawbacks) on blood circulation, thus suggesting that the tested compounds might represent a cornerstone of beneficial drug candidates for the safe treatment for erectile dysfunction.

Improvement of conventional anti-cancer drugs as new tools against multidrug resistant tumors

Multidrug resistance (MDR) is the dominant cause of the failure of cancer chemotherapy. The design of antitumor drugs that are able to evade MDR is rapidly evolving, showing that this area of biomedical research attracts great interest in the scientific community. The current review explores promising recent approaches that have been developed with the aim of circumventing or overcoming MDR. Encouraging results have been obtained in the investigation of the MDR-modulating properties of various classes of natural compounds and their analogues. Inhibition of P-gp or downregulation of its expression have proven to be the main mechanisms by which MDR can be surmounted. The use of hybrid molecules that are able to simultaneously interact with two or more cancer cell targets is currently being explored as a means to circumvent drug resistance. This strategy is based on the design of hybrid compounds that are obtained either by merging the structural features of separate drugs, or by conjugating two drugs or pharmacophores via cleavable/non-cleavable linkers. The approach is highly promising due to the pharmacokinetic and pharmacodynamic advantages that can be achieved over the independent administration of the two individual components. However, it should be stressed that the task of obtaining successful multivalent drugs is a very challenging one. The conjugation of anticancer agents with nitric oxide (NO) donors has recently been developed, creating a particular class of hybrid that can combat tumor drug resistance. Appropriate NO donors have been shown to reverse drug resistance via nitration of ABC transporters and by interfering with a number of metabolic enzymes and signaling pathways. In fact, hybrid compounds that are produced by covalently attaching NO-donors and antitumor drugs have been shown to elicit a synergistic cytotoxic effect in a variety of drug resistant cancer cell lines. Another strategy to circumvent MDR is based on nanocarrier-mediated transport and the controlled release of chemotherapeutic drugs and P-gp inhibitors. Their pharmacokinetics are governed by the nanoparticle or polymer carrier and make use of the enhanced permeation and retention (EPR) effect, which can increase selective delivery to cancer cells. These systems are usually internalized by cancer cells via endocytosis and accumulate in endosomes and lysosomes, thus preventing rapid efflux. Other modalities to combat MDR are described in this review, including the pharmaco-modulation of acridine, which is a well-known scaffold in the development of bioactive compounds, the use of natural compounds as means to reverse MDR, and the conjugation of anticancer drugs with carriers that target specific tumor-cell components. Finally, the outstanding potential of in silico structure-based methods as a means to evaluate the ability of antitumor drugs to interact with drug transporters is also highlighted in this review. Structure-based design methods, which utilize 3D structural data of proteins and their complexes with ligands, are the most effective of the in silico methods available, as they provide a prediction regarding the interaction between transport proteins and their substrates and inhibitors. The recently resolved X-ray structure of human P-gp can help predict the interaction sites of designed compounds, providing insight into their binding mode and directing possible rational modifications to prevent them from becoming P-gp drug substrates. In summary, although major efforts were invested in the search for new tools to combat drug resistant tumors, they all require further implementation and methodological development. Further investigation and progress in the abovementioned strategies will provide significant advances in the rational combat against cancer MDR.

Synthesis and Biological Evaluation of Acridine/Acridone Analogs as Potential Anticancer Agents

BACKGROUND

The lack of efficacious therapy for advanced melanoma and neuroblastoma makes new approaches necessary. Therefore, many scientists seek new, more effective, more selective and less toxic anticancer drugs.

OBJECTIVE

We propose the synthesis of the new functionalized analogs of 1-nitroacridine/4- nitroacridone connected to tuftsin/retro-tuftsin derivatives as potential anticancer agents.

METHODS

Acridine and acridone analogues were prepared by Ullmann condensation and then cyclization reaction. As a result of nucleophilic substitution reaction 1-nitro-9-phenoxyacridine or 1- chloro-4-nitro-9(10H)-acridone with the corresponding peptides, the planned acridine derivatives (10a-c, 12, 17-a-d, 19) have been obtained. The cytotoxic activity of the newly obtained analogs were evaluated against melanotic (Ma) and amelanotic (Ab) melanoma cell lines and neuroblastoma SH-SY5Y by using the XTT method. Apoptosis and cell cycle were analyzed by flow cytometry.

RESULTS

Among the investigated analogs compound 12 exhibited the highest potency comparable to dacarbazine action for amelanotic Ab melanoma cells. FLICA test (flurochrome-labeled inhibitors of caspases) showed that this analog significantly increased the content of cells with activated caspases (C+) among both neuroblastoma lines and only Ab melanoma line. Using phosphatidylserine (PS) externalization assay, 12 induced changes in the Ab melanoma plasma membrane structure as the externalization of phosphatidylserine (An+ cells). These changes in neuroblastoma cells were less pronounced.

CONCLUSION

Analog 12 could be proposed as the new potential chemotherapeutic against amelanotic melanoma form especially.

Gaseous signaling molecules and their application in resistant cancer treatment: from invisible to visible

Multidrug resistance (MDR) in cancer remains a critical obstacle for efficient chemotherapy. Many MDR reversal agents have been discovered but failed in clinical trials due to severe toxic effects. Gaseous signaling molecules (GSMs), such as oxygen, nitric oxide, hydrogen sulfide and carbon monoxide, play key roles in regulating cell biological function and MDR. Compared with other toxic chemosensitizing agents, GSMs are endogenous and biocompatible molecules with little side effects. Research show that GSM modulators, including pharmaceutical formulations of GSMs (combined with conventional chemotherapeutic drugs) and GSM-donors (small molecules with GSMs releasing property), can overcome or reverse MDR. This review discusses the roles of these four GSMs in modulating MDR, and summarizes GSMs modulators in treating cancers with drug resistance.

Design, synthesis and biological study of hybrid drug candidates of nitric oxide releasing cucurbitacin-inspired estrone analogs for treatment of hepatocellular carcinoma

Development of hybrid drug candidates is well known strategy for designing antitumor agents. Herein, a novel class of nitric oxide donating cucurbitacin inspired estrone analogs (NO-CIEAs) were designed and synthesized as multitarget agents. Synthesized analogs were initially evaluated for their anti-hepatocellular carcinoma activities. Among the tested analogs, NO-CIEAs 17 and 20a exhibited more potent activity against HepG2 cells (IC₅₀ = 4.69 and 12.5 µM, respectively) than the reference drug Erlotinib (IC₅₀ = 25 µM). Interestingly, NO-CIEA 17 exerted also a high potent activity against Erlotinib-resistant HepG2 cell line (HepG2-R) (IC₅₀ = 8.21 µM) giving insight about its importance in drug resistance therapy. Intracellular measurements of NO revealed that NO-CIEAs 17 and 20a showed a significant increase in NO production in tumor cells after 1 h of incubation comparable to the reference prodrug JS-K. Flow cytometric analysis showed that both NO-CIEAs 17 and 20a mainly arrested the HepG2 cells in the G0/G1 phase. Also, In-Cell Based ELISA screening showed that NO-CIEA 17 resulted in a potential inhibitory activity towards the EGFR and MAPK (25% and 29% inhibition compared to untreated control cells, respectively). This data suggests the binding ability of NO-CIEA 17 to the EGFR and ERK to be well correlated along with the docking and cellular studies. Also, treatment of HepG2-R cells with NO-CIEA 17 showed a potential reduction of MRP2 expression in a dose dependent manner providing a significant impact on the chemotherapeutic resistance. Overall, the current study provides a potential new approach for the discovery of a novel antitumor agent against HCC.

Copper-catalyzed coupling of anthranils and α-keto acids: direct synthesis of α-ketoamides

Copper-catalyzed coupling of α-keto acids with anthranils is reported for the synthesis of α-ketoamides bearing an aldehyde group via N–O/C–O bond cleavages and C–N bond formation.

Medicinal chemistry of acridine and its analogues

'Acridine' along with its functional analogue 'Acridone' is the most privileged pharmacophore in medicinal chemistry with diverse applications ranging from DNA intercalators, endonuclease mimics, ratiometric selective ion sensors, and P-glycoprotein inhibitors in countering the multi-drug resistance, enzyme inhibitors, and reversals of neurodegenerative disorders. Their interaction with DNA and ability of selectively identifying numerous biologically useful ions has cemented exploitability of the acridone nucleus in modern day therapeutics. Additionally, most derivatives and salts of acridine are planar, crystalline, and stable displaying a strong fluorescence which, when coupled with their marked bio selectivity and low cytotoxicity, enables the studying and monitoring of several biochemical, metabolic, and pharmacological processes. In this review, a detailed picture covering the important therapeutic aspects of the acridone nucleus and its functional analogues is discussed.

Design and synthesis of pyrazolo[3,4-d]pyrimidines: Nitric oxide releasing compounds targeting hepatocellular carcinoma

A new series of pyrazolo[3,4-d]pyrimidines tethered with nitric oxide (NO) producing functionality was designed and synthesized. Sulforhodamine B (SRB) protein assay revealed that NO releasing moiety in the synthesized compounds significantly decreased the cell growth more than the des-NO analogues. Compounds 7C and 7G possessing N-para-substituted phenyl group, released the highest NO concentration of 4.6% and 4.7% respectively. Anti-proliferative activity of synthesized compounds on HepG2 cell line identified compounds 7h, 7p, 14a and 14b as the most cytotoxic compounds in the series of IC₅₀=3, 5, 3 and 5μM, respectively, compared to erlotinib as a reference drug (IC₅₀=25μM). Flow cytometry studies revealed that 7h arrested the cells in G0/G1 phase of cell cycle while 7p arrested the cells in S phase. Moreover, docking study of the synthesized compounds on EGFR (PDB code: 1M17) and cytotoxicity study indicated that N-1 phenyl para substitution, pyrazole C-3 alkyl substitution and tethering the nitrate moiety through butyl group had a significant impact on the activity.

Site-selective Cp*Rh(iii)-catalyzed C–H amination of indolines with anthranils

The pyrimidinyl-directed C–H functionalization of indolines with anthranils as amination sources under rhodium(iii) catalysis is described to afford a range of C7-aminated indoline derivatives with excellent site-selectivity and functional group compatibility.

Recent developments in the synthesis and biological activity of acridine/acridone analogues

Many people in the world struggle with cancer or bacterial, parasitic, viral, Alzheimer's and other diseases.

Light-Responsive Biodegradable Nanomedicine Overcomes Multidrug Resistance via NO-Enhanced Chemosensitization

Multidrug resistance (MDR) is responsible for the relatively low effectiveness of chemotherapeutics. Herein, a nitric oxide (NO) gas-enhanced chemosensitization strategy is proposed to overcome MDR by construction of a biodegradable nanomedicine formula based on BNN6/DOX coloaded monomethoxy(polyethylene glycol)-poly(lactic-co-glycolic acid) (mPEG-PLGA). On one hand, the nanomedicine features high biocompatibility due to the high density of PEG and biodegradable PLGA. On the other hand, the nanoformula exhibits excellent stability under physiological conditions but exhibits stimuli-responsive decomposition of BNN6 for NO gas release upon ultraviolet-visible irradiation. More importantly, after NO release is triggered, gas molecules are generated that break the nanoparticle shell and lead to the release of doxorubicin. Furthermore, NO was demonstrated to reverse the MDR of tumor cells and enhance the chemosensitization for doxorubicin therapy.

Synthesis of biocompatible polymeric nanomaterial dually loaded with paclitaxel and nitric oxide for anti-MDR cancer therapy

A copolymer nanomedicine mPEG–PEI–PLLA–PTX–NO was synthesized and studied in an OVCAR-8/ADR MDR cancer model.