Design, synthesis, and evaluation of novel heteroaromatic analogs of curcumin as anti-cancer agents

Penta-1,4-dien-3-one and quinoxaline conjugates as potential anticancer agents via inhibiting EphB3/SRC/AKT axis

Overexpression of EphB3 has been documented across various cancers and essential for cell proliferation, survive and metastasis, making it a valuable therapeutic target. In this study, a series of novel penta-1,4-dien-3-one and quinoxaline conjugates were designed and synthesized using pharmacophore fusion strategies to explore potential EphB3 inhibitors. CCK-8 experiments revealed significant anti-cancer activity of most newly synthesized compounds against hepatocellular carcinoma (HCC). Among them, compound W8 displaying the highest inhibitory activity against MHCC97H (IC50 = 1.87 μM), which arrests MHCC97H cells in the G0/G1 phase and induces apoptosis. Furthermore, compound W8 suppresses tumor growth in an MHCC97H xenograft model in vivo by suppressing phosphorylation level of EphB3 and down-regulating the SRC-AKT signaling pathway, leading to a dose-dependent reduction in tumor volumes and weights, with a 40 mg/kg dose achieving decreases of 68.4 % and 65.3 %, respectively. Given its ability to modulate EphB3 signaling, W8 represents a promising lead compound for further drug development, particularly for cancers characterized by EphB3 overexpression, and may offer new opportunities for targeted therapy in precision oncology.

Wip1 phosphatase activator QGC-8-52 specifically sensitizes p53-negative cancer cells to chemotherapy while protecting normal cells

PP2C serine-threonine phosphatase Wip1 plays an important role in normal tissue homeostasis, stress signaling and pathogenesis of various human diseases. It is an attractive drug target for cancer treatment and inhibition of its expression or activity constitute a novel therapeutic intervention strategy to prevent the development of various cancers. However, previous strategies for Wip1 suppression may be ineffective in cancers lacking p53. Here, we have characterized the activity of a novel Wip1 phosphatase activator, QGC-8-52, in preclinical models of breast malignancies. QGC-8-52 significantly sensitizes the cancer cell lines with p53 deletion to chemotherapeutic agents. This effect was mediated by the Wip1-FOXO3a interaction and subsequent dephosphorylation of Thr487 that resulted, in response to anticancer treatment, in enhancing the transcription activity of FOXO3a on the proapoptotic TRAIL gene. The sensitizing effect of Wip1 activation on chemotherapeutic drugs only targeted cancer cells lacking p53. The activation of Wip1 in normal cells provided protection from anticancer drug-induced apoptosis by reducing the strength of upstream signaling to p53. Therefore, during the treatment of anticancer drugs, the activated Wip1 phosphatase boosts the apoptosis of p53-negative tumors and protects normal tissues. Our findings may represent an effective and safe therapeutic strategy for cancers with p53 deletion.

Anticancer perspectives of monocarbonyl analogs of curcumin: A decade (2014-2024) review

Monocarbonyl analogs of curcumin (MACs) represent structurally modified versions of curcumin. The existing literature indicates that MACs exhibit enhanced anticancer properties compared with curcumin. Numerous research articles in recent years have emphasized the significance of MACs as effective anticancer agents. This review focuses on the latest advances in the anticancer potential of MACs, from 2014 to 2024, including discussions on their mechanism of action, structure-activity relationship (SAR), and in silico molecular docking studies.

Effects of curcumin and ursolic acid in prostate cancer: A systematic review

The major barriers to phytonutrients in prostate cancer therapy are non-specific mechanisms and bioavailability issues. Studies have pointed to a synergistic combination of curcumin (CURC) and ursolic acid (UA). We investigate this combination using a systematic review process to assess the most likely mechanistic pathway and human testing in prostate cancer. We used the PRISMA statement to screen titles, abstracts, and the full texts of relevant articles and performed a descriptive analysis of the literature reviewed for study inclusion and consensus of the manuscript. The most common molecular and cellular pathway from articles reporting on the pathways and effects of CURC (n = 173) in prostate cancer was NF-κB (n = 25, 14.5%). The most common molecular and cellular pathway from articles reporting on the pathways and effects of UA (n = 24) in prostate cancer was caspase 3/caspase 9 (n = 10, 41.6%). The three most common molecular and cellular pathway from articles reporting on the pathways and effects of both CURC and UA (n = 193) in prostate cancer was NF-κB (n = 28, 14.2%), Akt (n = 22, 11.2%), and androgen (n = 19, 9.6%). Therefore, we have identified the potential synergistic target pathways of curcumin and ursolic acid to involve NF-κB, Akt, androgen receptors, and apoptosis pathways. Our review highlights the limited human studies and specific effects in prostate cancer.

Comprehensive Review on Recent Strategies for Management of Prostate Cancer: Therapeutic Targets and SAR

Prostate cancer is a disease that is affecting a large population worldwide. Androgen deprivation therapy (ADT) has become a foundation for the treatment of advanced prostate cancer, as used in most clinical settings from neo-adjuvant to metastatic stage. In spite of the success of ADT in managing the disease in the majority of men, hormonal manipulation fails eventually. New molecules are developed for patients with various hormone-refractory diseases. Advancements in molecular oncology have increased understanding of numerous cellular mechanisms which control cell death in the prostate and these insights can lead to the development of more efficacious and tolerable therapies for carcinoma of the prostate. This review is focused on numerous therapies that might be a boon for prostate therapy like signaling inhibitors, vaccines, and inhibitors of androgen receptors. Along with these, various bioactive molecules and their derivatives are highlighted, which act as potential antiprostate cancer agents. This article also emphasized the recent advances in the field of medicinal chemistry of prostate cancer agents.

Steric Effects on the Chelation of Mn2+ and Zn2+ by Hexadentate Polyimidazole Ligands: Modeling Metal Binding by Calprotectin Site 2

Recently, there has been increasing interest in the design of ligands that bind Mn2+ with high affinity and selectivity, but this remains a difficult challenge. It has been proposed that the cavity size of the binding pocket is a critical factor in most synthetic and biological examples of selective Mn2+ binding. Here, we use a bioinspired approach adapted from the hexahistidine binding site of the manganese-sequestering protein calprotectin to systematically study the effect of cavity size on Mn2+ and Zn2+ binding. We have designed a hexadentate, trisimidazole ligand whose cavity size can be tuned through peripheral modification of the steric bulk of the imidazole substituents. Conformational dynamics and redox potentials of the complexes are dependent on ligand steric bulk. Stability constants are consistent with the hypothesis that larger ligand cavities are relatively favorable for Mn2+ over Zn2+ , but this effect alone may not be sufficient to achieve Mn2+ selectivity.

Design, synthesis, in vitro and in silico evaluation of anti-colorectal cancer activity of curcumin analogues containing 1,3-diphenyl-1H-pyrazole targeting EGFR tyrosine kinase

Recent studies have shown that monocarbonyl analogues of curcumin (MACs) and 1H-pyrazole heterocycle both demonstrated promising anticancer activities, in which several compounds containing these scaffolds could target EGFR. In this research, 24 curcumin analogues containing 1H-pyrazole (a1-f4) were synthesized and characterized by using modern spectroscopic techniques. Firstly, synthetic MACs were screened for cytotoxicity against human cancer cell lines such as SW480, MDA-MB-231 and A549, from which the 10 most potential cytotoxic compounds were identified and selected. Subsequently, the selected MACs were further screened for their inhibition against tyrosine kinases, which showed that a4 demonstrated the most significant inhibitory effects on EGFR^WT and EGFR^L858R. Based on the results, a4 further demonstrated its ability to cause morphological changes, to increase the percentage of apoptotic cells, and to increase caspase-3 activity, suggesting its apoptosis-inducing activity on SW480 cells. In addition, the effect of a4 on the SW480 cell cycle revealed its ability to arrest SW480 cells at G₂/M phase. In subsequent computer-based assessments, a4 was predicted to possess several promising physicochemical, pharmacokinetic, and toxicological properties. Via molecular docking and molecular dynamics simulation, a reversible binding mode between a4 and EGFR^WT, EGFR^L858R, or EGFR^G719S, remained stable within the 100-ns simulation due to effective interactions especially the hydrogen bonding with M793. Finally, free binding energy calculations suggested that a4 could inhibit the activity of EGFR^G719S more effectively than other EGFR forms. In conclusion, our work would provide the basis for the future design of promising synthetic compounds as anticancer agents targeting EGFR tyrosine kinase.

Modified Curcumins as Potential Drug Candidates for Breast Cancer: An Overview

Breast cancer (BC), the most common malignancy in women, results from significant alterations in genetic and epigenetic mechanisms that alter multiple signaling pathways in growth and malignant progression, leading to limited long-term survival. Current studies with numerous drug therapies have shown that BC is a complex disease with tumor heterogeneity, rapidity, and dynamics of the tumor microenvironment that result in resistance to existing therapy. Targeting a single cell-signaling pathway is unlikely to treat or prevent BC. Curcumin (a natural yellow pigment), the principal ingredient in the spice turmeric, is well-documented for its diverse pharmacological properties including anti-cancer activity. However, its clinical application has been limited because of its low solubility, stability, and bioavailability. To overcome the limitation of curcumin, several modified curcumin conjugates and curcumin mimics were developed and studied for their anti-cancer properties. In this review, we have focused on the application of curcumin mimics and their conjugates for breast cancer.

Synthesis and biological testing of 3,5-bis(arylidene)-4-piperidone conjugates with 2,5-dihydro-5H-1,2-oxaphospholenes

Using the methodology of "click" chemistry, a series of conjugates of 3,5-bis(benzylidene)-1-(prop-2-yn)piperidin-4-ones with 4-alkyl-3-azidomethyl-2-ethoxy-2,5-dihydro-5H-1,2 oxaphosphol 2-oxides was synthesized. All newly obtained compounds 8-18 were characterized by ¹H, ¹³C, ³¹P, ¹⁹F NMR and IR spectroscopy. The potential antitumor activity of the synthesized conjugates8-18was studied in terms of their ability to influence the viability of variouscancercell lines, including A549, SH-SY5Y, Hep-2, and HeLa. Compound 15, which contains two fluorine atoms in the benzene ring, was shown to be the most promising. The mechanism of the cytotoxic action of this conjugate is supposed to be associated with the ability to inhibit the glycolytic profile of transformed cells.

Synthesis, Biological Evaluation, and Molecular Modeling Studies of 1-Aryl-1H-pyrazole-Fused Curcumin Analogues as Anticancer Agents

Addressing the growing burden of cancer and the shortcomings of chemotherapy in cancer treatment are the current research goals. Research to overcome the limitations of curcumin and to improve its anticancer activity via its heterocycle-fused monocarbonyl analogues (MACs) has immense potential. In this study, 32 asymmetric MACs fused with 1-aryl-1H-pyrazole (7a-10h) were synthesized and characterized to develop new curcumin analogues. Subsequently, via initial screening for cytotoxic activity, nine compounds exhibited potential growth inhibition against MDA-MB-231 (IC₅₀ 2.43-7.84 μM) and HepG2 (IC₅₀ 4.98-14.65 μM), in which seven compounds showing higher selectivities on two cancer cell lines than the noncancerous LLC-PK1 were selected for cell-free in vitro screening for effects on microtubule assembly activity. Among those, compounds 7d, 7h, and 10c showed effective inhibitions of microtubule assembly at 20.0 μM (40.76-52.03%), indicating that they could act as microtubule-destabilizing agents. From the screening results, three most potential compounds, 7d, 7h, and 10c, were selected for further evaluation of cellular effects on breast cancer MDA-MB-231 cells. The apoptosis-inducing study indicated that these three compounds could cause morphological changes at 1.0 μM and could enhance caspase-3 activity (1.33-1.57 times) at 10.0 μM in MDA-MB-231 cells, confirming their apoptosis-inducing activities. Additionally, in cell cycle analysis, compounds 7d and 7h at 2.5 μM and 10c at 5.0 μM also arrested MDA-MB-231 cells in the G₂/M phase. Finally, the results from in silico studies revealed that the predicted absorption, distribution, metabolism, excretion, and the toxicity (ADMET) profile of the most potent MACs might have several advantages in addition to potential disadvantages, and compound 7h could bind into (ΔG -10.08 kcal·mol^-1) and access wider space at the colchicine-binding site (CBS) than that of colchicine or nocodazole via molecular docking studies. In conclusion, our study serves as a basis for the design of promising synthetic compounds as anticancer agents in the future.

Recent advances of curcumin derivatives in breast cancer

Curcumin is a potential plant-derived drug for the treatment of breast cancer. Poor solubility and bioavailability are the main factors that limit its clinical application. Various structural modification strategies have been developed to improve the anti-breast cancer activity of curcumin. This review focuses on the difference of modification sites and heterocyclic/non-heterocyclic modifications to systematically summarize curcumin derivatives with better anti-breast cancer activity.

Synthesis of new curcumin-based aminocarbonitrile derivatives incorporating 4H-pyran and 1,4-dihydropyridine heterocycles

A multicomponent reaction containing curcumin, aldehydes, malononitrile and amine was developed for the one-pot synthesis of a novel library of 4H-pyran and 1,4-dihyropyridin heterocycles incorporating curcumin moiety. The products were obtained in the presence of p-toluenesulfonic acid as catalyst in ethanol as solvent in good to excellent yields.

Comp34 displays potent preclinical antitumor efficacy in triple-negative breast cancer via inhibition of NUDT3-AS4, a novel oncogenic long noncoding RNA

The abnormal PI3K/AKT/mTOR pathway is one of the most common genomic abnormalities in breast cancers including triple-negative breast cancer (TNBC), and pharmacologic inhibition of these aberrations has shown activity in TNBC patients. Here, we designed and identified a small-molecule Comp34 that suppresses both AKT and mTOR protein expression and exhibits robust cytotoxicity towards TNBC cells but not nontumorigenic normal breast epithelial cells. Mechanically, long noncoding RNA (lncRNA) AL354740.1-204 (also named as NUDT3-AS4) acts as a microRNA sponge to compete with AKT1/mTOR mRNAs for binding to miR-99s, leading to decrease in degradation of AKT1/mTOR mRNAs and subsequent increase in AKT1/mTOR protein expression. Inhibition of lncRNA-NUDT3-AS4 and suppression of the NUDT3-AS4/miR-99s association contribute to Comp34-affected biologic pathways. In addition, Comp34 alone is effective in cells with secondary resistance to rapamycin, the best-known inhibitor of mTOR, and displays a greater in vivo antitumor efficacy and lower toxicity than rapamycin in TNBC xenografted models. In conclusion, NUDT3-AS4 may play a proproliferative role in TNBC and be considered a relevant therapeutic target, and Comp34 presents promising activity as a single agent to inhibit TNBC through regulation of NUDT3-AS4 and miR-99s.

Discovery of 1,4-pentadien-3-one derivatives containing quinoxaline scaffolds as potential apoptosis inducers

Aim: To synthesize novel antiproliferative agents. Results & methodology: A variety of 1,4-pentadien-3-one derivatives bearing quinoxaline scaffolds was designed and synthesized and their antiproliferative activities were evaluated. Notably, compounds N3 and N4 exhibited markedly greater antiproliferative activities against SMMC-7721 cells in vitro compared with the well-known antitumor drug gemcitabine. The mechanistic investigation showed that compounds N3 and N4 induced SMMC-7721 cell apoptosis by regulating the expression levels of apoptosis-related proteins. In addition, the molecular docking model further revealed that compound N3 could be a potential peroxisome proliferator-activated receptor inhibitor. Conclusion: These compounds might serve as bioactive fragments and lead compounds for developing more potent apoptosis inducers.

Diarylpentanoids with antitumor activity: A critical review of structure-activity relationship studies

Diarypentanoids are commonly considered as monocarbonyl analogues of curcumin. Since the discovery of this compound in 1962, twenty one diarylpentanoids have been isolated and almost 600 synthetic analogues with antitumor activity have been synthesized. This review reports the exploitation of diarylpentanoids to develop curcumin analogues with improved antitumor activity over the last two decades. The mechanism of action and structure-activity relationship (SAR) studies are also highlighted. More importantly, structural features for the antitumor activity that may guide the design of new and more effective diarylpentanoids are also proposed.

Effects of green synthesised silver nanoparticles (ST06-AgNPs) using curcumin derivative (ST06) on human cervical cancer cells (HeLa) in vitro and EAC tumor bearing mice models

Background

In recent years, green synthesized silver nanoparticles have been increasingly investigated for their anti-cancer potential. In the present study, we aimed at the biosynthesis of silver nanoparticles (AgNPs) using a curcumin derivative, ST06. Although, the individual efficacies of silver nanoparticles or curcumin derivatives have been studied previously, the synergistic cytotoxic effects of curcumin derivative and silver nanoparticles in a single nanoparticulate formulation have not been studied earlier specifically on animal models. This makes this study novel compared to the earlier synthesized curcumin derivative or silver nanoparticles studies. The aim of the study was to synthesize ST06 coated silver nanoparticles (ST06-AgNPs) using ST06 as both reducing and coating agent.

Methods

The synthesized nanoparticles AgNPs and ST06-AgNPs were characterised for the particle size distribution, morphology, optical properties and surface charge by using UV-visible spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). Elemental composition and structural properties were studied by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction spectroscopy (XRD). The presence of ST06 as capping agent was demonstrated by Fourier transform infrared spectroscopy (FTIR).

Results

The synthesized nanoparticles (ST06-AgNPs) were spherical and had a size distribution in the range of 50–100 nm. UV-Vis spectroscopy displayed a specific silver plasmon peak at 410 nm. The in vitro cytotoxicity effects of ST06 and ST06-AgNPs, as assessed by MTT assay, showed significant growth inhibition of human cervical cancer cell line (HeLa). In addition, studies carried out in EAC tumor-induced mouse model (Ehrlich Ascites carcinoma) using ST06-AgNPs, revealed that treatment of the animals with these nanoparticles resulted in a significant reduction in the tumor growth, compared to the control group animals.

Conclusion

In conclusion, green synthesized ST06-AgNPs exhibited superior anti-tumor efficacy than the free ST06 or AgNPs with no acute toxicity under both in vitro and in vivo conditions. The tumor suppression is associated with the intrinsic apoptotic pathway. Together, the results of this study suggest that ST06-AgNPs could be considered as a potential option for the treatment of solid tumors.

Targeting of PP2Cδ By a Small Molecule C23 Inhibits High Glucose-Induced Breast Cancer Progression In Vivo

Aims: Epidemiologic evidence indicates that diabetes may increase risk of breast cancer (BC) and mortality in patients with cancer. The pathophysiological relationships between diabetes and cancer are not fully understood, and personalized treatments for diabetes-associated BC are urgently needed. Results: We observed that high glucose (HG), via activation of nuclear phosphatase PP2Cδ, suppresses p53 function, and consequently promotes BC cell proliferation, migration, and invasion. PP2Cδ expression is higher in tumor tissues from BC patients with hyperglycemia than those with normoglycemia. The mechanisms underlying HG stimulation of PP2Cδ involve classical/novel protein kinase-C (PKC) activation and GSK3β phosphorylation. Reactive oxygen species (ROS)/NF-κB pathway also mediates HG induction of PP2Cδ. Furthermore, we identified a 1,5-diheteroarylpenta-1,4-dien-3-one (Compound 23, or C23) as a novel potent PP2Cδ inhibitor with a striking cytotoxicity on MCF-7 cells through cell-based screening assay for growth inhibition and activity of a group of curcumin mimics. Beside directly inhibiting PP2Cδ activity, C23 blocks HG induction of PP2Cδ expression via heat shock protein 27 (HSP27) induction and subsequent ablation of ROS/NF-κB activation. C23 can thus significantly block HG-triggered inhibition of p53 activity, leading to the inhibition of cancer cell proliferation, migration, and invasion. In addition, hyperglycemia promotes BC development in diabetic nude mice, and C23 inhibits the xenografted BC tumor growth. Conclusions and Innovation: Our findings elucidate mechanisms that may have contributed to diabetes-associated BC progression, and provide the first evidence to support the possible alternative therapeutic approach to BC patients with diabetes. Antioxid. Redox Signal. 30, 1983-1998.

Biological Potential and Mechanism of Prodigiosin from Serratia marcescens Subsp. lawsoniana in Human Choriocarcinoma and Prostate Cancer Cell Lines

Tripyrrole molecules have received renewed attention due to reports of numerous biological activities, including antifungal, antibacterial, antiprotozoal, antimalarial, immunosuppressive, and anticancer activities. In a screen of bacterial strains with known toxicities to termites, a red pigment-producing strain, HDZK-BYSB107, was isolated from Chamaecyparis lawsoniana, which grows in Oregon, USA. Strain HDZK-BYSB107 was identified as Serratia marcescens subsp. lawsoniana. The red pigment was identified as prodigiosin using ultraviolet absorption, LC-MS, and 1H-NMR spectroscopy. The bacterial prodigiosin had an inhibitory effect on both Gram-negative and Gram-positive bacteria. The main objective of this study was to explore the anticancer activities and mechanism of strain HDZK-BYSB107 prodigiosin by using human choriocarcinoma (JEG3) and prostate cancer cell lines (PC3) in vitro and JEG3 and PC3 tumor-bearing nude mice in vivo. In vitro anticancer activities showed that the bacterial prodigiosin induced apoptosis in JEG3 cells. In vivo anticancer activities indicated that the prodigiosin significantly inhibited the growth of JEG3 and PC3 cells, and the inhibitory activity was dose and time dependent. The anticancer efficacy of the bacterial prodigiosin on JEG3 and PC3 cells, JEG3 and PC3 tumor exhibited a correlation with the down regulation of the inhibitor of IAP family, including XIAP, cIAP-1 and cIAP-2, and the activation of caspase-9 and caspase-3 accompanied by proteolytic degradation of poly (ADP-ribose)-polymerase. The expressions of P53 and Bax/Bcl-2 in JEG3 and PC3 cells were significantly higher than in untreated groups. Our results indicated that the bacterial prodigiosin extracted from C. lawsoniana is a promising molecule due to its potential for therapeutic applications.

Optimization of diarylpentadienones as chemotherapeutics for prostate cancer

Our earlier studies indicate that (1E,4E)-1,5-bis(1-alkyl-1H-imidazol-2-yl)penta-1,4-diene-3-ones and (1E,4E)-1,5-bis(1-alkyl-1H-benzo[d]imidazol-2-yl)penta-1,4-diene-3-ones exhibit up to 121-fold greater antiproliferative potency than curcumin in human prostate cancer cell models, but only 2-10 fold increase in mouse plasma concentrations. The present study aims to further optimize them as anti-prostate cancer agents with both good potency and bioavailability. (1E,4E)-1,5-Bis(1H-imidazol-2-yl)penta-1,4-diene-3-one, the potential metabolic product of (1E,4E)-1,5-bis(1-alkyl-1H-imidazol-2-yl)penta-1,4-diene-3-ones, was synthesized and evaluated for its anti-proliferative activity. The promising potency of 1,5-bis(1-alkyl-1H-imidazol-2-yl)penta-1,4-diene-3-ones was completely abolished by removing the 1-alkyl group, suggesting the critical role of an appropriate group on the N1 position. We then envisioned that N-aryl substitution to exclude the C-H bond on the carbon adjacent to the N1 position (α-H) may increase the metabolic stability. Consequently, seven (1E,4E)-1,5-bis(1-aryl-1H-imidazol-2-yl)penta-1,4-dien-3-ones and three (1E,4E)-1,5-bis(1-aryl-1H-benzo[d]imidazol-2-yl)penta-1,4-dien-3-ones, as well as three (1E,4E)-1,5-bis(1-aryl-1H-pyrrolo[3,2-b]pyridine-2-yl)penta-1,4-dien-3-ones, were synthesized through a three-step transformation, including N-arylation via Ullmann condensation, formylation, and Horner-Wadsworth-Emmons reaction. Six optimal (1E,4E)-1,5-bis(1-aryl-1H-imidazol-2-yl)penta-1,4-dien-3-ones exhibit 24- to 375-fold improved potency as compared with curcumin. Replacement of the imidazole with bulkier benzoimidazole and 4-azaindole results in a substantial decrease in the potency. (1E,4E)-1,5-Bis(1-(2-methoxyphenyl)-1H-imidazol-2-yl)penta-1,4-dien-3-one (17d) was established as an optimal compound with both superior potency and good bioavailability that is sufficient to provide the therapeutic efficacy necessary to suppress in vivo tumor growth.

Anticancer potential of novel curcumin analogs towards castrate-resistant prostate cancer

Prostate cancer is initially sensitive to hormone therapy; however, over time the majority of patients progress to a hormone-insensitive form classified as castration-resistant prostate cancer (CRPC). CRPC is highly metastatic and patients have a poor prognosis. Thus, new drugs for the treatment of this disease are required. In this study, we therefore examined the cytotoxic effects and anticancer mechanism(s) of action of second generation curcumin analogs towards CRPC cells. For this purpose, PC3 and DU145 cells were treated with a series of curcumin analogs at 0-10 µM for 72 h and cytotoxicity was determined by the sulforhodamine B (SRB) assay. Two compounds, 1-isopropyl-3,5-bis(pyridin-3-ylmethylene)-4-piperidone (RL118) and 1-methyl-3,5-[(6-methoxynaphthalen-2-yl)methylene]-4-piperidone (RL121), were found to have the most potent cytotoxic effect with EC50 values of 0.50 and 0.58 µM in the PC3 cells and EC50 values of 0.76 and 0.69 µM in the DU145 cells, respectively. Thus, further experiments were performed focusing on these two compounds. Flow cytometry was performed to determine their effects on the cell cycle and apoptosis. Both analogs increased the number of cells in the G2/M phase of the cell cycle and induced apoptosis. Specifically, in the PC3 cells, RL121 increased the number of cells in the G2/M phase by 86% compared to the control, while RL118 increased the number of cells in the G2/M phase by 42% compared to the control after 24 h. Moreover, both RL118 and RL121 induced the apoptosis of both cell lines. In the DU145 cells, a 38-fold increase in the number of apoptotic cells was elicited by RL118 and a 78-fold increase by RL121 compared to the control. Furthermore, the effects of both analogs on the expression of key proteins involved in cell proliferation were also determined by western blot analysis. The results revealed that both analogs inhibited the expression of nuclear factor (NF)-κB (p65/RelA), eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), p-4E-BP1, mammalian target of rapamycin (mTOR), p-mTOR, AKT and p-AKT. Thus, the findings of this study provide evidence that RL118 and RL121 have potent anticancer activity against CPRC cells, and both analogs warrant further investigation in vivo.

Synthesis, evaluation of cytotoxic properties of promising curcumin analogues and investigation of possible molecular mechanisms

Curcumin is a popular, plant-derived compound that has been extensively investigated for diverse range of biological activities. Anticancer activity against various types of cancers and high-safety profile associated with curcumin makes it very attractive. In this study, we report the synthesis and evaluation of pyrazole and click chemistry curcumin analogues for Head and Neck cancer. MTT assay against head and neck cancer cell lines CAL27 and UM-SCC-74A revealed the micromolar potency of the synthesized compounds. To determine the possible molecular mechanisms, effect of these analogues in the expression of pSTAT3, pFAK, pERK1/2 and pAKT was studied. Interestingly, compounds 2 and 5 significantly inhibited the pSTAT3 (Tyr 705) phosphorylation. As far as other compounds, they showed potent cytotoxicity against CAL27; however, these compounds did not show any activity on pSTAT3 phosphorylation at IC₅₀ concentration level. Molecular docking studies revealed the possible binding mode of pyrazole compound 2 in the SH2 domain of STAT3.

Design, Synthesis and Bioactivities of Novel 1,4-Pentadien-3-one Derivatives Containing a Substituted Pyrazolyl Moiety

In this study, in order to find novel biologically active penta-1,4-dien-3-one derivatives, a series of penta-1,4-dien-3-one compounds containing a substituted pyrazole subunit were designed and synthesized. Their structures were characterized by ¹H-NMR, ¹³C-NMR and elemental analysis. The preliminary bioassays displayed that most of the title compounds showed significant antiproliferative activity against HepG2 cell lines. Especially, compounds 7a–m, o, r, s, u, w, y and z were active against HepG2 cells with IC₅₀ values of 0.10–5.05 μM, which were superior to that of the contrast sorafenib (IC₅₀ = 16.20 μM).

Asymmetric 1,5-diarylpenta-1,4-dien-3-ones: Antiproliferative activity in prostate epithelial cell models and pharmacokinetic studies

To further engineer dienones with optimal combinations of potency and bioavailability, thirty-four asymmetric 1,5-diarylpenta-1,4-dien-3-ones (25-58) have been designed and synthesized for the evaluation of their in vitro anti-proliferative activity in three human prostate cancer cell lines and one non-neoplastic prostate epithelial cell line. All these asymmetric dienones are sufficiently more potent than curcumin and their corresponding symmetric counterparts. The optimal dienone 58, with IC₅₀ values in the range of 0.03-0.12 μM, is 636-, 219-, and 454-fold more potent than curcumin in three prostate cancer cell models. Dienones 28 and 49 emerged as the most promising asymmetric dienones that warrant further preclinical studies. The two lead compounds demonstrated substantially improved potency in cell models and superior bioavailability in rats, while exhibiting no acute toxicity in the animals at the dose of 10 mg/kg. Dienones 28 and 46 can induce PC-3 cell cycle regulation at the G₀/G₁ phase. However, dienone 28 induces PC-3 cell death in a different way from 46 even though they share the same scaffold, indicating that terminal heteroaromatic rings are critical to the action of mechanism for each specific dienone.

Structure-activity relationship studies of 1,7-diheteroarylhepta-1,4,6-trien-3-ones with two different terminal rings in prostate epithelial cell models

To systematically investigate the structure-activity relationships of 1,7-diheteroarylhepta-1,4,6-trien-3-ones in three human prostate cancer cell models and one human prostate non-neoplastic epithelial cell model, thirty five 1,7-diarylhepta-1,4,6-trien-3-ones with different terminal heteroaromatic rings have been designed for evaluation of their anti-proliferative potency in vitro. These target compounds have been successfully synthesized through two sequential Horner-Wadsworth-Emmons reactions starting from the appropriate aldehydes and tetraethyl (2-oxopropane-1,3-diyl)bis(phosphonate). Their anti-proliferative potency against PC-3, DU-145 and LNCaP human prostate cancer cell lines can be significantly enhanced by the manipulation of the terminal heteroaromatic rings, further demonstrating the utility of 1,7-diarylhepta-1,4,6-trien-3-one as a potential scaffold for the development of anti-prostate cancer agents. The optimal analog 40 is 82-, 67-, and 39-fold more potent than curcumin toward the three prostate cancer cell lines, respectively. The experimental data also reveal that the trienones with two different terminal aromatic rings possess greater potency toward three prostate cancer cell lines, but also have greater capability of suppressing the proliferation of PWR-1E benign human prostate epithelial cells, as compared to the corresponding counterparts with two identical terminal rings and curcumin. The terminal aromatic rings also affect the cell apoptosis perturbation.

Synthesis and biological evaluation of curcumin inspired indole analogues as tubulin polymerization inhibitors

In our endeavour towards the development of potent cytotoxic agents, a series of some new curcumin inspired indole analogues, in which indole and phenyl moieties are linked on either sides of 1,5-diaryl-1,4-pentadien-3-one system have been synthesized and characterized by spectral data. All the newly synthesized analogues were tested for their cytotoxic potential against a panel of eight cancer cell lines namely, lung (A549), breast (MDA-MB-231, BT549 and 4T1), prostate (PC-3, DU145), gastric (HGC-27) and cervical (HeLa). Notably, among all the compounds tested, compounds 11c, 11d and 11f showed potent growth inhibition on PC-3 and BT549 with IC₅₀ values in the range of 3.12-6.34 μM and 4.69-8.72 μM respectively. The most active compound (11c) was also tested on RWPE-1 (normal prostate) cells and was found to be safe compared to the PC-3 cells. In tubulin polymerization assay, compounds 11c and 11f effectively inhibited microtubule assembly with IC₅₀ values of 10.21 ± 0.10 and 8.83 ± 0.06 μM respectively. The results from molecular modelling studies revealed that these compounds bind at the colchicine binding site of the tubulin. Moreover, DAPI and acridine orange/ethidium bromide staining studies indicated that compounds 11c and 11f can induce apoptosis in PC-3 cells. Further flow-cytometry analysis revealed that compound 11c arrests PC-3 cells in G2/M phase of the cell cycle while compound 11f treatment resulted in moderate increase in the G2/M population. Additionally, the treatment by these compounds led to the impairment of mitochondrial membrane potential (DΨm) in PC-3 cells.

Design, synthesis, and biological evaluation of 1,9-diheteroarylnona-1,3,6,8-tetraen-5-ones as a new class of anti-prostate cancer agents

In search of more effective chemotherapeutics for the treatment of castration-resistant prostate cancer and inspired by curcumin analogues, twenty five (1E,3E,6E,8E)-1,9-diarylnona-1,3,6,8-tetraen-5-ones bearing two identical terminal heteroaromatic rings have been successfully synthesized through Wittig reaction followed by Horner-Wadsworth-Emmons reaction. Twenty-three of them are new compounds. The WST-1 cell proliferation assay was employed to assess their anti-proliferative effects toward both androgen-sensitive and androgen-insensitive human prostate cancer cell lines. Eighteen out of twenty-five synthesized compounds possess significantly improved potency as compared with curcumin. The optimal compound, 78, is 14- to 23-fold more potent than curcumin in inhibiting prostate cancer cell proliferation. It can be concluded from our data that 1,9-diarylnona-1,3,6,8-tetraen-5-one can serve as a new potential scaffold for the development of anti-prostate cancer agents and that pyridine-4-yls and quinolin-4-yl act as optimal heteroaromatic rings for the enhanced potency of this scaffold. Two of the most potent compounds, 68 and 75, effectively suppress PC-3 cell proliferation by activating cell apoptosis and by arresting cell cycle in the G0/G1 phase.

Synthesis and evaluation of 1,7-diheteroarylhepta-1,4,6-trien-3-ones as curcumin-based anticancer agents

Thirty (1E,4E,6E)-1,7-diaryl-1,4,6-heptatrien-3-ones, featuring a central linear trienone linker and two identical nitrogen-containing heteroaromatic rings, were designed and synthesized as curcumin-based anticancer agents on the basis of their structural similarity to the enol-tautomer of curcumin, in addition to taking advantage of the possibly enhanced pharmacokinetic profiles contributed by the basic nitrogen-containing heteroaromatic rings. Their cytotoxicity and antiproliferative activity were evaluated towards both androgen-dependent and androgen-independent prostate cancer cell lines, as well as HeLa human cervical cancer cells. Among them, the ten most potent analogues are 5- to 36-fold more potent than curcumin in inhibiting cancer cell proliferation. The acquired structure-activity relationship data indicate (i) that (1E,4E,6E)-1,7-diaryl-1,4,6-heptatrien-3-ones represent a potential scaffold for development of curcumin-based agents with substantially improved cytotoxicity and anti-proliferative effect; and (ii) 1-alkyl-1H-imidazol-2-yl and 1-alkyl-1H-benzo[d]imidazole-2-yl serve as optimal heteroaromatic rings for increased in vitro potency of this scaffold. Two of most potent compounds displayed no apparent cytotoxicity toward MCF-10A normal mammary epithelial cells at 1 μM concentration. Treatment of PC-3 prostate cancer cells with the most potent compound led to appreciable cell cycle arrest at a G1/G0 phase and cell apoptosis induction.

Synthesis and Biological Evaluation of Curcumin Derivatives with Water-Soluble Groups as Potential Antitumor Agents: An in Vitro Investigation Using Tumor Cell Lines

Three series of curcumin derivatives including phosphorylated, etherified, and esterified products of curcumin were synthesized, and their anti-tumor activities were assessed against human breast cancer MCF-7, hepatocellular carcinoma Hep-G2, and human cervical carcinoma HeLa cells. Compared with curcumin, compounds 3, 8, and 9 exhibited stronger antitumor cell line growth activities against HeLa cells. Compound 12 also showed higher antitumor cell line growth activities on MCF-7 cells than curcumin. Among them, 4-((1E,6E)-7-(4-Hydroxy-3-methoxyphenyl)-3,5-dioxohepta-1,6-dienyl)-2-methoxyphenyl dihydrogen phosphate(3) showed the strongest activity with an half maximal inhibitory concentration (IC₅₀) of 6.78 µM against HeLa cells compared with curcumin with an IC₅₀ of 17.67 µM. Stabilities of representatives of the three series were tested in rabbit plasma in vitro, and compounds 3 and 4 slowly released curcumin in plasma. The effect of compound 3 on HeLa cell apoptosis was determined by examining morphological changes by DAPI (4′,6-diamidino-2-phenylindole) staining as well as Annexin V-FITC/ Propidium Iodide (PI) double staining and flow cytometry. The results showed that 3 induced cellular apoptosis in a dose-dependent manner. Together our findings show that 3 merits further investigation as a new potential antitumor drug candidate.

Recent developments in curcumin and curcumin based polymeric materials for biomedical applications: A review

Turmeric (Curcuma longa) is a popular Indian spice that has been used for centuries in herbal medicines for the treatment of a variety of ailments such as rheumatism, diabetic ulcers, anorexia, cough and sinusitis. Curcumin (diferuloylmethane) is the main curcuminoid present in turmeric and responsible for its yellow color. Curcumin has been shown to possess significant anti-inflammatory, anti-oxidant, anti-carcinogenic, anti-mutagenic, anticoagulant and anti-infective effects. This review summarizes and discusses recently published papers on the key biomedical applications of curcumin based materials. The highlighted studies in the review provide evidence of the ability of curcumin to show the significant vitro antioxidant, diabetic complication, antimicrobial, neuroprotective, anti-cancer activities and detection of hypochlorous acid, wound healing, treatment of major depression, healing of paracentesis, and treatment of carcinoma and optical detection of pyrrole properties. Hydrophobic nature of this polyphenolic compound along with its rapid metabolism, physicochemical and biological instability contribute to its poor bioavailability. To redress these problems several approaches have been proposed like encapsulation of curcumin in liposomes and polymeric micelles, inclusion complex formation with cyclodextrin, formation of polymer-curcumin conjugates, etc.

A new class of hybrid anticancer agents inspired by the synergistic effects of curcumin and genistein: Design, synthesis, and anti-proliferative evaluation

Inspired by the synergistic effects of dietary natural products with different scaffolds on the inhibition of cancer cell proliferation, incorporation of central (1E,4E)-1,4-penta-dien-3-one linker (an optimal substitute for the central metabolically unstable diketone linker of curcumin), 1-alkyl-1H-imidazol-2-yl (a promising bioisostere of terminal aryl group in curcumin), and chromone (the common pharmacophore in genistein and quercetin) into one chemical entity resulted in ten new hybrid molecules, 3-((1E,4E)-5-(1-alkyl-1H-imidazol-2-yl)-3-oxopenta-1,4-dien-1-yl)-4H-chromen-4-ones. They were synthesized through a three-step transformation using acid-catalyzed aldol condensation as key step. The WST-1 cell proliferation assay showed that they have greater anti-proliferative potency than curcumin, quercetin, and genistein on both androgen-dependent and androgen-independent human prostate cancer cells.

Structure-Activity Relationship and Pharmacokinetic Studies of 1,5-Diheteroarylpenta-1,4-dien-3-ones: A Class of Promising Curcumin-Based Anticancer Agents

Forty-three 1,5-diheteroaryl-1,4-pentadien-3-ones were designed as potential curcumin mimics, structurally featuring a central five-carbon dienone linker and two identical nitrogen-containing aromatic rings. They were synthesized using a Horner-Wadsworth-Emmons reaction as the critical step and evaluated for their cytotoxicity and antiproliferative activities toward both androgen-insensitive and androgen-sensitive prostate cancer cell lines and an aggressive cervical cancer cell line. Most of the synthesized compounds showed distinctly better in vitro potency than curcumin in the four cancer cell lines. The structure-activity data acquired from the study validated (1E,4E)-1,5-dihereroaryl-1,4-pentadien-3-ones as an excellent scaffold for in-depth development for clinical treatment of prostate and cervical cancers. 1-Alkyl-1H-imidazol-2-yl, ortho pyridyl, 1-alkyl-1H-benzo[d]imidazole-2-yl, 4-bromo-1-methyl-1H-pyrazol-3-yl, thiazol-2-yl, and 2-methyl-4-(trifluoromethyl)thiazol-5-yl were identified as optimal heteroaromatic rings for the promising in vitro potency. (1E,4E)-1,5-Bis(2-methyl-4-(trifluoromethyl)thiazol-5-yl)penta-1,4-dien-3-one, featuring thiazole rings and trifluoromethyl groups, was established as the optimal lead compound because of its good in vitro potency and attractive in vivo pharmacokinetic profiles.

Design, synthesis, and antiviral activity of novel rutin derivatives containing 1, 4-pentadien-3-one moiety

Rutin (compound 5) and some compounds (compounds 1-4 and 6) were isolated from Artemisia princeps Pamp (A. princeps Pamp.) and a series of novel rutin derivatives containing 1,4-pentadien-3-one moiety were designed and synthesized. The target compounds were characterized by proton nuclear magnetic resonance spectroscopy ((1)H NMR), carbon nuclear magnetic resonance spectroscopy ((13)C NMR), and ESI-MS. Bioassay results indicated that some of the compounds showed good to excellent antiviral activities against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV) at 500 μg/mL in vivo. The 50% effective concentrations (EC50) of the compound 7r against CMV was 394.78 μg/mL, which was better than that of Ningnanmycin (432.22 μg/mL). These results indicated that novel rutin derivatives containing 1,4-pentadien-3-one moiety can effectively control CMV.

Molecular targets of naturopathy in cancer research: bridge to modern medicine

The relevance of naturopathy (defined as the practice of medicine for the treatment of human diseases with natural agents) in human cancer is beginning to be appreciated, as documented by renewed interest in nutraceutical research, the natural anticancer agents of dietary origin. Because of their pleiotropic effects and the ability to modulate multiple signaling pathways, which is a good attribute of natural agents, nutraceuticals have frequently been demonstrated to re-sensitize drug-resistant cancers. The effectiveness of nutraceuticals can be further enhanced if the tools for the relative assessment of their molecular targets are readily available. Such information can be critical for determining their most effective uses. Here, we discuss the anticancer potential of nutraceuticals and the associated challenges that have interfered with their translational potential as a naturopathic approach for the management of cancers. In the years to come, an efficient screening and assessment of molecular targets will be the key to make rapid progress in the area of drug design and discovery, especially focusing on evidence-based development of naturopathy for the treatment of human malignancies.

Eliminating the heart from the curcumin molecule: monocarbonyl curcumin mimics (MACs)

Curcumin is a natural product with several thousand years of heritage. Its traditional Asian application to human ailments has been subjected in recent decades to worldwide pharmacological, biochemical and clinical investigations. Curcumin’s Achilles heel lies in its poor aqueous solubility and rapid degradation at pH ~ 7.4. Researchers have sought to unlock curcumin’s assets by chemical manipulation. One class of molecules under scrutiny are the monocarbonyl analogs of curcumin (MACs). A thousand plus such agents have been created and tested primarily against cancer and inflammation. The outcome is clear. In vitro, MACs furnish a 10–20 fold potency gain vs. curcumin for numerous cancer cell lines and cellular proteins. Similarly, MACs have successfully demonstrated better pharmacokinetic (PK) profiles in mice and greater tumor regression in cancer xenografts in vivo than curcumin. The compounds reveal limited toxicity as measured by murine weight gain and histopathological assessment. To our knowledge, MAC members have not yet been monitored in larger animals or humans. However, Phase 1 clinical trials are certainly on the horizon. The present review focuses on the large and evolving body of work in cancer and inflammation, but also covers MAC structural diversity and early discovery for treatment of bacteria, tuberculosis, Alzheimer’s disease and malaria.

All trans 1-(3-arylacryloyl)-3,5-bis(pyridin-4-ylmethylene)piperidin-4-ones as curcumin-inspired antineoplastics

A series of eleven N-acryloyl/N-cinnamoyl 3,5-bis(pyridin-4-yl)methylene-4-piperidones were synthesized as curcumin-based candidate antineoplastic agents. The cytostatic potency of these compounds was evaluated against three representative cell lines and all compounds were found to exhibit significant anti-cancer cell activity in vitro. QSAR studies using several physicochemical parameters and 50% inhibitory concentration (IC50) values resulted in certain important correlations which will aid design of more potent analogs. Representative test compounds were investigated in the NCI 60-cell line panel where they were found to display a profound cytotoxicity. These compounds were also potent anti-oxidants and inhibitors of human topoisomerase IIα. Representative compounds were well-tolerated by human fibroblasts and by mice during the survival/toxicity studies.