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

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.

Design, synthesis, and evaluation of cyclic C7-bridged monocarbonyl curcumin analogs containing an o-methoxy phenyl group as potential agents against gastric cancer

The structure-activity relationship (SAR) between toxicity and the types of linking ketones of C7 bridged monocarbonyl curcumin analogs (MCAs) was not clear yet. In the pursuit of effective and less cytotoxic chemotherapeutics, we conducted a SAR analysis using various diketene skeletons of C7-bridged MCAs, synthesized cyclic C7-bridged MCAs containing the identified low-toxicity cyclopentanone scaffold and an o-methoxy phenyl group, and assessed their anti-gastric cancer activity and safety profile. Most compounds exhibited potent cytotoxic activities against gastric cancer cells. We developed a quantitative structure-activity relationship model (R2 > 0.82) by random Forest method, providing important information for optimizing structure. An optimized compound 2 exhibited in vitro and in vivo anti-gastric cancer activity partly through inhibiting the AKT and STAT3 pathways, and displayed a favorable in vivo safety profile. In summary, this paper provided a promising class of MCAs and a potential compound for the development of chemotherapeutic drugs.

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.

Synthesis and studies of new purines/pyrimidine derivatives as multi-targeted agents involving various receptor sites in the immune system

Pro-inflammation, which is developed due to the increased production of cytokines, mainly interleukin-6 (IL-6), during the working of immune system pathways, becomes a major concern these days for many researchers. So, it is desired to design, screen, and synthesize new molecules with multi-parametric features showing their efficacy for Toll-like receptors (TLRs) and inhibiting the disease-causing receptor sites like viral infections, cancers, etc. along with controlling inflammation, fever, and other side effects during such pathways. Further, looking at the literature, curcumin a multi-targeted agent is showing its efficiency toward various receptor sites involved in many diseases as mentioned above. This fascinated us to build up new molecules which behave like curcumin with minimum side effects. In silico studies, involving ADMET studies, toxicological data, and docking analyses, of newly synthesized compounds (3-5) along with tautomers of curcumin i.e., (1-2), and some reported compounds like 9 and 10 have been studied in detail. Great emphasis has been made on analyzing binding energies, protein-ligand structural interactions, stabilization of newly synthesized molecules against various selected receptor sites using such computational tools. Compound 3 is the most efficient multifunctional agent, which has shown its potential toward most of the receptor sites in docking analysis. It has also responded well in Molecular dynamics (MD) simulation toward 5ZLN, 4RJ3, 4YO9, 4YOJ, and 1I1R sites. Finally, studies were extended to understand in vitro anti-inflammatory activity for particularly compound 3 in comparison to diclofenac and curcumin, which signifies the efficiency of compound 3.

New insights of structural activity relationship of curcumin and correlating their efficacy in anticancer studies with some other similar molecules

Recently, Cancer is the widespread category of different diseases in human beings, and its progress is linked with a number of factors such as estrogen level, diet, hereditary etc. Curcumin is a naturally occurring compound which appears to be significant clinical for applications in vitro as well as in vivo studies. Many of the research groups have been paying attention towards natural products for the development of anticancer drugs. Curcumin, Rosmarinic acid and Chalcone are the naturally occurring compounds, which are chemopreventive and chemotherapeutic. In present review the anticancer activity of curcumin and similar analogues in vitro has been discussed on the basis of inhibitory concentration (IC50). Also this data is compared with the inhibitory concentration of chalcone, its derivatives and rosmarinic acid.

Developments in the anticancer activity of structurally modified curcumin: An up-to-date review

Curcumin is a pharmacologically active polyphenol derived from the popular spice element-Turmeric. The therapeutic activity of curcumin has been extensively investigated over the last few decades and reports suggest the role of curcumin in a large number of biological activities, particularly its prominent anticancer activity. Curcumin, being a pleiotropic molecule, is a regulator of multiple molecular targets which play crucial roles in various cell signaling pathways. It is known to suppress transformation, inhibit proliferation as well as induce apoptosis. However, despite all these benefits, the efficacy of curcumin remains limited due to its poor bioavailability, poor absorption within the systemic circulation and rapid elimination from the body. To overcome these limiting factors, researchers all around the world are working towards designing a synthetic and superior curcuminoid by making suitable structural modifications to the parent skeleton. These curcuminoids, mainly analogues and derivatives, will not only improve the physicochemical properties but also enhance the efficacy simultaneously. The present review will provide a comprehensive account of the analogues and derivatives of curcumin that have been reported since 2014 which have indicated a better anticancer activity than curcumin.

Chemopreventive efficacy of curcumin-loaded PLGA microparticles in a transgenic mouse model of HER-2-positive breast cancer

Curcumin has shown promising inhibitory activity against HER-2-positive tumor cells in vitro but suffers from poor oral bioavailability in vivo. Our lab has previously developed a polymeric microparticle formulation for sustained delivery of curcumin for chemoprevention. The goal of this study was to examine the anticancer efficacy of curcumin-loaded polymeric microparticles in a transgenic mouse model of HER-2 cancer, Balb-neuT. Microparticles were injected monthly, and mice were examined for tumor appearance and growth. Initiating curcumin microparticle treatment at 2 or 4 weeks of age delayed tumor appearance by 2-3 weeks compared to that in control mice that received empty microparticles. At 12 weeks, abnormal (lobular hyperplasia, carcinoma in situ, and invasive carcinoma) mammary tissue area was significantly decreased in curcumin microparticle-treated mice, as was CD-31 staining. Curcumin treatment decreased mammary VEGF levels significantly, which likely contributed to slower tumor formation. When compared to saline controls, however, blank microparticles accelerated tumorigenesis and curcumin treatment abrogated this effect, suggesting that PLGA microparticles enhance tumorigenesis in this model. PLGA microparticle administration was shown to be associated with higher plasma lactic acid levels and increased activation of NF-κΒ. The unexpected side effects of PLGA microparticles may be related to the high dose of the microparticles that was needed to achieve sustained curcumin levels in vivo. Approaches that can decrease the overall dose of curcumin (for example, by increasing its potency or reducing its clearance rate) may allow the development of sustained release curcumin dosage forms as a practical approach to cancer chemoprevention.

Recent advances (2015-2016) in anticancer hybrids

In spite of the development of a large number of novel anticancer drugs over the years, Cancer remains as a prominent cause of death, worldwide. Numerous drugs that are currently in clinical practice have developed multidrug resistance along with fatal side effects. Therefore, the utilization of single-target therapy is incapable of providing an effective control on the malignant process. Molecular hybridization, involving a combination of two or more pharmacophores of bioactive scaffolds to generate a single molecular architecture with improved affinity and activity, in comparison to their parent molecules, has emerged as a promising strategy in recent drug discovery research. Hybrid anticancer drugs are of great therapeutic interests since they can potentially overcome most of the pharmacokinetic drawbacks encountered with conventional anticancer drugs. Strategically, the design of anticancer drugs involved the blending or linking of an anticancer drug with another anticancer drug or a carrier molecule which can efficiently target cancer cells with improved biological potential. Major advantages of hybrid anticancer drugs involved increased specificity, better patient compliance, and lower side effects along with reduction in chemo-resistance. The successful utilization of this technique in design and synthesis of novel anticancer hybrids has been well illustrated and documented in the literature. The purpose of the present review article will be to provide an emphasis on the recent developments (2015-16) in anticancer hybrids with insights into their structure-activity relationship (SAR) and mechanism of action.

Activation of anti-oxidant Nrf2 signaling by enone analogues of curcumin

Inflammation and oxidative stress are common in many chronic diseases. Targeting signaling pathways that contribute to these conditions may have therapeutic potential. The transcription factor Nrf2 is a major regulator of phase II detoxification and anti-oxidant genes as well as anti-inflammatory and neuroprotective genes. Nrf2 is widespread in the CNS and is recognized as an important regulator of brain inflammation. The natural product curcumin exhibits numerous biological activities including ability to induce the expression of Nrf2-dependent phase II and anti-oxidant enzymes. Curcumin has been examined in a number of clinical studies with limited success, mainly owing to limited bioavailability and rapid metabolism. Enone analogues of curcumin were examined with an Nrf2 reporter assay to identify Nrf2 activators. Analogues were separated into groups with a 7-carbon dienone spacer, as found in curcumin; a 5-carbon enone spacer with and without a ring; and a 3-carbon enone spacer. Activators of Nrf2 were found in all three groups, many of which were more active than curcumin. Dose-response studies demonstrated that a range of substituents on the aromatic rings of these enones influenced not only the sensitivity to activation, reflected in EC₅₀ values, but also the extent of activation, which suggests that multiple mechanisms are involved in the activation of Nrf2 by these analogues.

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.

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.

Therapeutic Nanoparticles Based on Curcumin and Bamboo Charcoal Nanoparticles for Chemo-Photothermal Synergistic Treatment of Cancer and Radioprotection of Normal Cells

Low water solubility, extensive metabolism, and drug resistance are the existing unavoidable disadvantages of the insoluble drug curcumin in biomedical applications. Herein, we employed d-α-tocopherol polyethylene glycol 1000 succinate (TPGS)-functionalized near-infrared (NIR)-triggered photothermal mesoporous nanocarriers with bamboo charcoal nanoparticles (TPGS-BCNPs) to load and deliver curcumin for improving its bioavailability. This system could considerably increase the accumulation of curcumin in cancer cells for enhanced curcumin bioavailability via simultaneously promoting the cellular internalization of the as-synthesized composite (TPGS-BCNPs@curcumin) by the size effect of NPs and considerably triggering controlled curcumin release from TPGS-BCNPs@curcumin by NIR stimulation and reducing efflux of curcumin by the P-glycoprotein (P-gp) inhibition of TPGS, so as to enhance the therapeutic effect of curcumin and realize a better chemo-photothermal synergetic therapy in vitro and in vivo. Besides cancer therapy, studies indicated that curcumin and some carbon materials could be used as radical scavengers that play an important role in the radioprotection of normal cells. Hence, we also investigated the free-radical-scavenging ability of the TPGS-BCNPs@curcumin composite in vitro to preliminarily evaluate its radioprotection ability for healthy tissues. Therefore, our work provides a multifunctional delivery system for curcumin bioavailability enhancement, chemo-photothermal synergetic therapy of cancer, and radioprotection of healthy tissues.

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.

New bis(hydroxymethyl) alkanoate curcuminoid derivatives exhibit activity against triple-negative breast cancer in vitro and in vivo

Novel bis(hydroxymethyl) alkanoate curcuminoid derivatives were designed, synthesized and screened for in vitro antiproliferative and in vivo antitumor activity. Selected new compound 9a and curcumin were further evaluated for inhibitory activity against ER⁺/PR⁺ breast cancer (MCF-7, T47D), HER 2⁺ breast cancer (SKBR3, BT474, and MDA-MB-457) and triple negative breast cancer (TNBC) (HS-578T, MDA-MB-157, and MDA-MB-468) cell lines. In addition, compound 9a was evaluated in the MDA-MB-231 xenograft nude mice model. Compound 9a exhibited greater inhibitory activity than curcumin against TNBC cells and also demonstrated significant inhibitory activity against doxorubicin-resistant MDA-MB-231 cells, with ten-fold higher potency than curcumin. Furthermore, when evaluated against the MDA-MB-231 xenograft nude mice model, compound 9a alone was ten-fold more potent than curcumin. Moreover, synergistic activity was observed when 9a was used in combination with doxorubicin against MDA-MB-231 breast cancer cells.

Platelet-12 lipoxygenase targeting via a newly synthesized curcumin derivative radiolabeled with technetium-99m

Background

One of the most popular techniques for cancer detection is the nuclear medicine technique. The present research focuses on Platelet-12-lipoxygenase (P-12-LOX) as a promising target for treating and radio-imaging tumor tissues. Curcumin was reported to inhibit this enzyme via binding to its active site.

Results

A novel curcumin derivative was successfully synthesized and characterized with yield of 74%. It was radiolabeled with the diagnostic radioisotope technetium-99m with 84% radiochemical yield and in vitro stability up to 6 h. The biodistribution studies in tumor bearing mice confirmed the high affinity predicted by the docking results with a free binding energy value of (ΔG −50.10 kcal/mol) and affinity (13.64 pki) showing high accumulation in solid tumor with target/non-target ratio >6.

Conclusion

The newly synthesized curcumin derivative, as a result of a computational study on platelet-12 lipoxygenase, showed its excellent free binding energy (∆G −50.10 kcal/mol) and high affinity (13.64 pKi). It could be an excellent radio-imaging agent that targeting tumor cells via targeting of P-12-LOX.Graphical abstract

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.