CLEFMA-an anti-proliferative curcuminoid from structure-activity relationship studies on 3,5-bis(benzylidene)-4-piperidones

Similarity based functionalization for enumeration of synthetically plausible chemical libraries surrounding a target

Functionalization of lead compounds to create analogs is a challenging step in discovering new molecules with desired properties and it is conducted throughout the chemical industry, including pharmaceuticals and agrochemicals. The process can be time-consuming and expensive, requiring expert intuition and experience. To help address synthesis planning challenges in late-stage functionalization, we have developed a molecular similarity approach that proposes single-step functionalization reactions based on analogy to precedent reactions. The developed approach mimics reaction strategies and suggests co-reactants defined implicitly by a corpus of known reactions. Using ca. 348 k reactions from the patent literature as a knowledge base, the recorded products or close analogs are among the top 20 proposed products in 74% of ∼44 k test reactions. The combinatorial growth inherent in recursive applications of the tool allows the enumeration of chemical libraries surrounding a target compound of interest. Moreover, each step of the resulting library synthesis leverages common chemical transformations reported in the literature accessible to most chemists.

Discovery of Novel Mono-Carbonyl Curcumin Derivatives as Potential Anti-Hepatoma Agents

Curcumin possesses a wide spectrum of liver cancer inhibition effects, yet it has chemical instability and poor metabolic properties as a drug candidate. To alleviate these problems, a series of new mono-carbonyl curcumin derivatives G1-G7 were designed, synthesized, and evaluated by in vitro and in vivo studies. Compound G2 was found to be the most potent derivative (IC50 = 15.39 μM) compared to curcumin (IC50 = 40.56 μM) by anti-proliferation assay. Subsequently, molecular docking, wound healing, transwell, JC-1 staining, and Western blotting experiments were performed, and it was found that compound G2 could suppress cell migration and induce cell apoptosis by inhibiting the phosphorylation of AKT and affecting the expression of apoptosis-related proteins. Moreover, the HepG2 cell xenograft model and H&E staining results confirmed that compound G2 was more effective than curcumin in inhibiting tumor growth. Hence, G2 is a promising leading compound with the potential to be developed as a chemotherapy agent for hepatocellular carcinoma.

Curcumin in human osteosarcoma: From analogs to carriers

Osteosarcoma (osteogenic sarcoma), the most prevalent primary malignant bone tumor in adolescents, confers low survival rates in patients with metastatic disease. Dietary curcumin has a number of anticancer properties but has poor bioavailability. To improve the clinical applications of curcumin, several potential curcumin analogs and nanobased curcumin delivery systems have been developed. In this critical review, we address the biological and pharmacological characteristics of curcumin and its analogs, with an emphasis on strategies to improve the bioactivity and bioavailability of curcumin analogs that may increase their application in the treatment of potent human metastatic osteosarcoma. We highlight promising current multifunctional nanoformulations and three-dimensional printed scaffold systems utilized for the targeting and delivery of curcumin in human osteosarcoma cells. Our purpose is to drive further research on curcumin analogs and carriers to improve their bioavailability and anti-osteosarcoma bioactivity.

CLEFMA induces intrinsic and extrinsic apoptotic pathways through ERK1/2 and p38 signalling in uterine cervical cancer cells

Although concurrent chemoradiotherapy is the cornerstone of treatment for locally advanced or recurrent uterine cervical cancer, treatment fails at a high rate. Therefore, the development of novel targeting agents is critical. This study investigated the action of CLEFMA, a potent, synthetic curcumin derivative, on cervical cancer cells and its mechanism of action. We found that CLEFMA negatively regulated the viability of cervical cancer cells, involving induction of cell apoptosis. Cleaved caspase-3, cleaved poly(adenosine diphosphate-ribose) polymerase, cleaved caspase-8, and cleaved caspase-9 expression were increased by treatment with CLEFMA. After U0126 (ERK1/2 inhibitor) and SB203580 (p38 inhibitor) were applied as cotreatment with CLEFMA, the expression of cleaved caspase-8, -9, and -3 was reduced significantly. In conclusion, CLEFMA activates both extrinsic and intrinsic apoptotic pathways through ERK1/2 and p38 signal transduction in cervical cancer cells.

Curcumin and its Analogs and Carriers: Potential Therapeutic Strategies for Human Osteosarcoma

Curcumin is a natural polyphenol phytochemical derived from turmeric with antioxidant, anti-inflammatory, and anticancer properties but is concerned about poor solubility in water, absorption, and metabolic stability. Potent metastatic osteosarcoma is the most common primary bone cancer in children, adolescents, and young adults. It is responsible for low survival rates because of its high rate of metastasis to the lungs. To improve poor bioavailability, numerous curcumin analogs were developed to possess anticancer characteristics through a variety of biological pathways involved in cytotoxicity, proliferation, autophagy, sensitizing chemotherapy, and metastases. This review provides an overview of their various pharmacological functions, molecular mechanisms, and therapeutic potential as a remedy for human osteosarcoma. To enhance therapeutic efficacy, several liposomal nanoparticles, nanocarriers, multifunctional micelles, and three-dimensional printed scaffolds have also been developed for the controlled delivery of curcumin targeting human osteosarcoma cells. Consequently, curcumin and several potential analogs and delivery formulations are optimistic candidates to improve the currently available strategy for human osteosarcoma. However, further insight into the mechanism of action of promising curcumin analogs and the development of carriers in clinical trials of osteosarcoma needs to be investigated to improve their overall potency and clinical utility, in particular the anti-metastatic effect.

CLEFMA Induces the Apoptosis of Oral Squamous Carcinoma Cells through the Regulation of the P38/HO-1 Signalling Pathway

The purpose of this research was to evaluate the impact and the underlying molecular mechanism of CLEFMA-induced cell death in human OSCC. The anti-tumour properties of CLEFMA in oral cancer were explored using colony formation, flow cytometry, human apoptosis array, Western blot, and immunohistochemistry assays. The in vivo anti-tumour effect of CLEFMA administered by oral gavage was evaluated using SCC-9-derived xenograft-bearing nude mouse models. CLEFMA significantly suppressed colony formation and elicited cellular apoptosis in oral cancer cells. CLEFMA treatment remarkably increased phosphorylated p38 and HO-1 along with cleavage of poly ADP-ribose polymerase and activation of caspase-8, -9, and -3 in HSC-3 and SCC-9 cells. Administration of HO-1 small interfering RNA significantly protected the cells from CLEFMA-induced caspase-3, -8, and -9 activation. Attenuation of p38 activity by the pharmacologic inhibitor SB203580 dramatically reduced CLEFMA-induced caspase-3, -8, and -9 activation and HO-1 expression in OSCC. The subcutaneous murine xenograft models showed that CLEFMA in vivo suppressed tumour growth in implanted SCC-9 cells. All of these findings indicated that CLEFMA induced apoptosis through the p38-dependent rise in HO-1 signal transduction cascades in OSCC.

Research Trend and Detailed Insights into the Molecular Mechanisms of Food Bioactive Compounds against Cancer: A Comprehensive Review with Special Emphasis on Probiotics

In an attempt to find a potential cure for cancer, scientists have been probing the efficacy of the food we eat and its bioactive components. Over the decades, there has been an exponentially increasing trend of research correlating food and cancer. This review explains the molecular mechanisms by which bioactive food components exhibit anticancer effects in several cancer models. These bioactive compounds are mainly plant based or microbiome based. While plants remain the primary source of these phytochemicals, little is known about probiotics, i.e., microbiome sources, and their relationships with cancer. Thus, the molecular mechanisms underlying the anticancer effect of probiotics are discussed in this review. The principal mode of cell death for most food bioactives is found to be apoptosis. Principal oncogenic signaling axes such as Akt/PI3K, JAK/STAT, and NF-κB seem to be modulated due to these bioactives along with certain novel targets that provide a platform for further oncogenic research. It has been observed that probiotics have an immunomodulatory effect leading to their chemopreventive actions. Various foods exhibit better efficacy as complete extracts than their individual phytochemicals, indicating an orchestrated effect of the food components. Combining bioactive agents with available chemotherapies helps synergize the anticancer action of both to overcome drug resistance. Novel techniques to deliver bioactive agents enhance their therapeutic response. Such combinations and novel approaches are also discussed in this review. Notably, most of the food components that have been studied for cancer have shown their efficacy in vivo. This bolsters the claims of these studies and, thus, provides us with hope of discovering anticancer agents in the food that we eat.

Anticancer Applications and Pharmacological Properties of Piperidine and Piperine: A Comprehensive Review on Molecular Mechanisms and Therapeutic Perspectives

Piperine and piperidine are the two major alkaloids extracted from black pepper (Piper nigrum); piperidine is a heterocyclic moiety that has the molecular formula (CH₂)₅NH. Over the years, many therapeutic properties including anticancer potential of these two compounds have been observed. Piperine has therapeutic potential against cancers such as breast cancer, ovarian cancer, gastric cancer, gliomal cancer, lung cancer, oral squamous, chronic pancreatitis, prostate cancer, rectal cancer, cervical cancer, and leukemia. Whereas, piperidine acts as a potential clinical agent against cancers, such as breast cancer, prostate cancer, colon cancer, lung cancer, and ovarian cancer, when treated alone or in combination with some novel drugs. Several crucial signalling pathways essential for the establishment of cancers such as STAT-3, NF-κB, PI3k/Aκt, JNK/p38-MAPK, TGF-ß/SMAD, Smac/DIABLO, p-IκB etc., are regulated by these two phytochemicals. Both of these phytochemicals lead to inhibition of cell migration and help in cell cycle arrest to inhibit survivability of cancer cells. The current review highlights the pharmaceutical relevance of both piperine and piperidine against different types of cancers.

Potential of natural products in osteosarcoma treatment: Focus on molecular mechanisms

Osteosarcoma is the most frequent type of bone cancer found in children and adolescents, and commonly arises in the metaphyseal region of tubular long bones. Standard therapeutic approaches, such as surgery, chemotherapy, and radiation therapy, are used in the management of osteosarcoma. In recent years, the mortality rate of osteosarcoma has decreased due to advances in treatment methods. Today, the scientific community is investigating the use of different naturally derived active principles against various types of cancer. Natural bioactive compounds can function against cancer cells in two ways. Firstly they can act as classical cytotoxic compounds by non-specifically affecting macromolecules, such as DNA, enzymes, and microtubules, which are also expressed in normal proliferating cells, but to a greater extent by cancer cells. Secondly, they can act against oncogenic signal transduction pathways, many of which are activated in cancer cells. Some bioactive plant-derived agents are gaining increasing attention because of their anti-cancer properties. Moreover, some naturally-derived compounds can significantly promote the effectiveness of standard chemotherapy drugs, and in certain cases are able to ameliorate drug-induced adverse effects caused by chemotherapy. In the present review we summarize the effects of various naturally-occurring bioactive compounds against osteosarcoma.

The roles, controversies, and combination therapies of autophagy in lung cancer

Lung cancer is one of the leading causes of death among men and women worldwide. The disease initially has a silent phenotype, which leads to the progression of the disease and ultimately the lack of proper response to routine treatments. Autophagy, known as an intracellular "recycle bin" for the degradation of defective proteins and molecules, is one of the mechanisms that has been considered in the context of cancer in recent years. This study aims to provide a comprehensive review of published articles on autophagy in the context of lung cancer to have a complete view of the role of autophagy in lung cancer and its possible treatments. PubMed, Scopus, and Google Scholar were searched until June 15 to find related articles. No specific search filters or restrictions were applied. The results were entered into reference management software for aggregation and management. The full text of all articles was screened and studied. In conclusion, studies on the exact function of autophagy in lung cancer are contradictory, but what can be concluded from a review of literature on lung cancer is that targeting autophagy combined with traditional routine therapies such as chemotherapy, especially in advanced stages of lung cancer, can be an effective anticancer approach.

Trifluoromethyl-substituted 3,5-bis(arylidene)-4-piperidones as potential anti-hepatoma and anti-inflammation agents by inhibiting NF-кB activation

Some methoxy-, hydroxyl-, pyridyl-, or fluoro-substituted 3,5-bis(arylidene)-4-piperidones (BAPs) could reduce inflammation and promote hepatoma cell apoptosis by inhibiting activation of NF-κB, especially after introduction of trifluoromethyl. Herein, a series of trifluoromethyl-substituted BAPs (4-30) were synthesised and the biological activities were evaluated. We successfully found the most potential 16, which contains three trifluoromethyl substituents and exhibits the best anti-tumour and anti-inflammatory activities. Preliminary mechanism research revealed that 16 could promote HepG2 cell apoptosis in a dose-dependent manner by down-regulating the expression of Bcl-2 and up-regulating the expression of Bax, C-caspase-3. Meanwhile, 16 inhibited activation of NF-κB by directly inhibiting the phosphorylation of p65 and IκBα induced by LPS, together with indirectly inhibiting MAPK pathway, thereby exhibiting both anti-hepatoma and anti-inflammatory activities. Molecular docking confirmed that 16 could bind to the active sites of Bcl-2, p65, and p38 reasonably. The above results suggested that 16 has enormous potential to be developed as a multifunctional agent for the clinical treatment of liver cancers and inflammatory diseases.

Perspectives for synthetic curcumins in chemoprevention and treatment of cancer: An update with promising analogues

Curcumin, a pure compound extracted from the flowering plant, turmeric (Curcuma longa. Zingiberaceae), is a common dietary ingredient found in curry powder. It has been studied extensively for its anti-inflammatory, antioxidant, antimicrobial and anti-tumour activities. Evidence is accumulating demonstrating its potential in chemoprevention and as an anti-tumour agent for the treatment of cancer. Despite demonstrated safety and tolerability, the clinical application of curcumin is frustrated by its poor solubility, metabolic instability and low oral bioavailability. Consequently researchers have tried novel techniques of formulation and delivery as well as synthesis of analogues with enhanced properties to overcome these barriers. This review presents the synthetic analogues of curcumin that have proven their anticancer potential from different studies. It also highlights studies that combined these analogues with approved chemotherapies and delivered them via novel techniques. Currently, there are no reports of clinical studies on any of the synthetic congeners of curcumin and this presents an opportunity for future research. This review presents the synthetic analogues of curcumin and makes a compelling argument for their potential application in the management of cancerous disease.

Hybridization of Curcumin Analogues with Cinnamic Acid Derivatives as Multi-Target Agents Against Alzheimer's Disease Targets

The synthesis of the new hybrids followed a hybridization with the aid of hydroxy-benzotriazole (HOBT) and 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI.HCL) in dry DMF or thionyl chloride between curcumin analogues and cinnamic acid derivatives. IR, 1H-NMR, 13C-NMR, LC/MS ESI+, and elemental analysis were used for the confirmation of the structures of the novel hybrids. The lipophilicity values of compounds were calculated theoretically and experimentally via the reversed chromatography method as RM values. The novel derivatives were studied through in vitro experiments for their activity as antioxidant agents and as inhibitors of lipoxygenase, cyclooxygenase-2, and acetyl-cholinesterase. All the compounds showed satisfying anti-lipid peroxidation activity of linoleic acid induced by 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH). Hybrid 3e was the most significant pleiotropic derivative, followed by 3a. According to the predicted results, all hybrids could be easily transported, diffused, and absorbed through the blood-brain barrier (BBB). They presented good oral bioavailability and very high absorption with the exception of 3h. No inhibition for CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 was noticed. According to the Ames test, all the hybrids induced mutagenicity with the exception of 3d. Efforts were conducted a) to correlate the in vitro results with the most important physicochemical properties of the structural components of the molecules and b) to clarify the correlation of actions among them to propose a possible mechanism of action. Docking studies were performed on soybean lipoxygenase (LOX) and showed hydrophobic interactions with amino acids. Docking studies on acetylcholinesterase (AChE) exhibited: (a) hydrophobic interactions with TRP281, LEU282, TYR332, PHE333, and TYR336 and (b) π-stacking interactions with TYR336.

ST09, A Novel Curcumin Derivative, Blocks Cell Migration by Inhibiting Matrix Metalloproteases in Breast Cancer Cells and Inhibits Tumor Progression in EAC Mouse Tumor Models

Purpose: Curcumin is known for its anticancer and migrastatic activity in various cancers, including breast cancer. Newer curcumin derivatives are being explored to overcome limitations of curcumin like low bioavailability, stability, and side effects due to its higher dose. In this study, the synthesis of ST09, a novel curcumin derivative, and its antiproliferative, cytotoxic, and migrastatic properties have been explored both in vitro and in vivo. Methods: After ST09 synthesis, anticancer activity was studied by performing standard cytotoxicity assays namely, lactate dehydrogenase (LDH) release assay, 3-(4, 5-dimethylthiazol-2-yl)-2–5-diphenyletrazolium bromide (MTT), and trypan blue exclusion assay. Annexin-FITC, cell cycle analysis using flow cytometry, and Western blotting were performed to elucidate cell death mechanisms. The effect on the inhibition of cell migration was studied by transwell migration assay. An EAC (Ehrlich Ascites carcinoma) induced mouse tumor model was used to study the effect of ST09 on tumor regression. Drug toxicity was measured using aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen (BUN), and flow-cytometry based lymphocyte count. Histological analysis was performed for assessment of any tissue injury post ST09 treatment. Results: ST09 shows an approximate 100-fold higher potency than curcumin, its parent compound, on breast tumor cell lines MCF-7 and MDA-MB231. ST09 arrests the cell cycle in a cell type-specific manner and induces an intrinsic apoptotic pathway both in vitro and in vivo. ST09 inhibits migration by downregulating matrix metalloprotease 1,2 (MMP1,2) and Vimentin. In vivo, ST09 administration led to decreased tumor volume in a mouse allograft model by boosting immunity with no significant drug toxicity. Conclusion: ST09 exhibits antiproliferative and cytotoxic activity at nanomolar concentrations. It induces cell death by activation of the intrinsic pathway of apoptosis both in vitro and in vivo. It also inhibits migration and invasion. This study provides evidence that ST09 can potentially be developed as a novel antitumor drug candidate for highly metastatic and aggressive breast cancer.

Tumor suppressive activities of solvatochromic 3,3'-azadimethylene dinaphthospiropyran in colon cancer model

Spiropyrans have been extensively investigated because of their thermo- and photochromic characteristics, but their biotherapeutic properties have not been explored much. We report anti-proliferative properties of a novel 3,3'-azadimethylene dinaphthospiropyran 11. Dibenzospiropyrans and dinaphthospiropyrans were synthesized by a simple and expedient method using acid-catalyzed aldol condensation of salicylaldehyde and 2-hydroxy-1-naphthaldehyde, respectively, with cyclic ketones. Together with structural elucidation by 2D NMR and X-ray crystallography studies, we provide a putative mechanism for their formation. Compound 11 showed solvatochromism and exhibited altered spectral characteristics depending on the pH. In acidic conditions, 11 remains in open form, whereas upon alkalinization it reverts back to closed form. Based on the in vitro anti-proliferative activity in H441, HCT-116, MiaPaCa-2, and Panc-1 cancer cell lines, 11 was submitted to further investigation. It reduced HCT116 colonosphere formation and demonstrated induction of caspase cascade, suggesting apoptosis. In vitro proliferation assays also suggested that HCl and trifluoroacetate salts of 11 are more effective. Treatment of mice carrying HCT-116 xenografts with 11 (5 µg/day, intraperitoneal for 3 weeks) suppressed tumor growth by 62%. Overall, the results reveal a new series of structurally complex, but relatively easy to synthesize molecules of which compound 11 represents a lead for anticancer development.

Properly Substituted Cyclic Bis-(2-bromobenzylidene) Compounds Behaved as Dual p300/CARM1 Inhibitors and Induced Apoptosis in Cancer Cells

Bis-(3-bromo-4-hydroxy)benzylidene cyclic compounds have been reported by us as epigenetic multiple ligands, but different substitutions at the two wings provided analogues with selective inhibition. Since the 1-benzyl-3,5-bis((E)-3-bromobenzylidene)piperidin-4-one 3 displayed dual p300/EZH2 inhibition joined to cancer-selective cell death in a panel of tumor cells and in in vivo xenograft models, we prepared a series of bis((E)-2-bromobenzylidene) cyclic compounds 4a–n to test in biochemical (p300, PCAF, SIRT1/2, EZH2, and CARM1) and cellular (NB4, U937, MCF-7, SH-SY5Y) assays. The majority of 4a–n exhibited potent dual p300 and CARM1 inhibition, sometimes reaching the submicromolar level, and induction of apoptosis mainly in the tested leukemia cell lines. The most effective compounds in both enzyme and cellular assays carried a 4-piperidone moiety and a methyl (4d), benzyl (4e), or acyl (4k–m) substituent at N1 position. Elongation of the benzyl portion to 2-phenylethyl (4f) and 3-phenylpropyl (4g) decreased the potency of compounds at both the enzymatic and cellular levels, but the activity was promptly restored by introduction of a ketone group into the phenylalkyl substituent (4h–j). Western blot analyses performed in NB4 and MCF-7 cells on selected compounds confirmed their inhibition of p300 and CARM1 through decrease of the levels of acetyl-H3 and acetyl-H4, marks for p300 inhibition, and of H3R17me2, mark for CARM1 inhibition.

Crystal structure and anti-inflammatory activity of (3E,5E)-3,5-bis(4-fluorobenzylidene)-1-((4-fluorophenyl)sulfonyl)piperidin-4-one-dichloromethane (1/1), C26H20Cl2F3NO3S

C26H20Cl2F3NO3S, triclinic, P1̄ (no. 2), a = 8.5616(4) Å, b = 11.6052(6) Å, c = 14.1451(8) Å, α = 66.617(6)°, β = 82.391(4)°, γ = 69.072(4)°, V = 1204.85(12) Å3, Z = 2, R gt(F) = 0.0460, wR ref(F 2) = 0.1206, T = 100.00(10) K.

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.

Hydroxyl-substituted double Schiff-base condensed 4-piperidone/cyclohexanones as potential anticancer agents with biological evaluation

Novel hydroxyl-substituted double Schiff-base 4-piperidone/cyclohexanone derivatives, 3a-e, 4a-e, 5a-d, and 6a-c, were synthesized and fully characterized by 1H NMR, IR and elemental analysis. The cytotoxicity against human carcinoma cell lines A549, SGC7901, HePG2, HeLa, K562, THP-1 and non-malignant LO2 cell lines were evaluated. The results showed 4-piperidinone derivatives displayed better cytotoxicity than cyclohexanone derivatives, especially for 3,4,5-trihydroxyphenyl-substituted BAP 5c. The western blot and flow cytometry results proved 5c can effectively promote cell apoptosis through up-regulating Bax protein and down-regulating Bcl-2 protein expression. Molecular docking modes showed that 5c could reasonably bind to the active site of Bcl-2 protein through strong intermolecular hydrogen bonds and significant hydrophobic effect. In vivo, 5c can effectively suppress the growth of HepG2 xenografts without apparent body weight changes. This study indicates that 5c can be a potential anticancer agent for early treatment of liver cancers.

Anti-Cancer and Ototoxicity Characteristics of the Curcuminoids, CLEFMA and EF24, in Combination with Cisplatin

In this study, we investigated whether the curcuminoids, CLEFMA and EF24, improved cisplatin efficacy and reduced cisplatin ototoxicity. We used the lung cancer cell line, A549, to determine the effects of the curcuminoids and cisplatin on cell viability and several apoptotic signaling mechanisms. Cellular viability was measured using the MTT assay. A scratch assay was used to measure cell migration and fluorescent spectrophotometry to measure reactive oxygen species (ROS) production. Western blots and luminescence assays were used to measure the expression and activity of apoptosis-inducing factor (AIF), caspases-3/7, -8, -9, and -12, c-Jun N-terminal kinases (JNK), mitogen-activated protein kinase (MAPK), and proto-oncogene tyrosine-protein kinase (Src). A zebrafish model was used to evaluate auditory effects. Cisplatin, the curcuminoids, and their combinations had similar effects on cell viability (IC₅₀ values: 2-16 μM) and AIF, caspase-12, JNK, MAPK, and Src expression, while caspase-3/7, -8, and -9 activity was unchanged or decreased. Cisplatin increased ROS yield (1.2-fold), and curcuminoid and combination treatments reduced ROS (0.75-0.85-fold). Combination treatments reduced A549 migration (0.51-0.53-fold). Both curcuminoids reduced auditory threshold shifts induced by cisplatin. In summary, cisplatin and the curcuminoids might cause cell death through AIF and caspase-12. The curcuminoids may potentiate cisplatin's effect against A549 migration, but may counteract cisplatin's effect to increase ROS production. The curcuminoids might also prevent cisplatin ototoxicity.

Chalcone derivatives targeting mitosis: synthesis, evaluation of antitumor activity and lipophilicity

This study describes the synthesis of a series of chalcones, including pyrazole and α,β-epoxide derivatives, and evaluation of their cell growth inhibitory activity in three human tumor cell lines, as well as their lipophilicity using liposomes as a biomimetic membrane model. Structure-activity and structure-lipophilicity relationships were established for the synthetized chalcones. From this work, nine chalcones (3, 5, 9, 11, 15-19) showing suitable drug-like lipophilicity with potent growth inhibitory activity were identified, being the growth inhibitory effect of compounds 15-17 associated with a pronounced antimitotic effect. Compounds 15-17 affected spindle assembly and, as a consequence, arrested cells at metaphase in NCI-H460 cells, culminating in cell death. Amongst the compounds tested, compound 15 exhibited the highest antimitotic activity as revealed by mitotic index calculation. Moreover, 15 was able to enhance chemosensitivity of tumor cells to low doses of paclitaxel in NCI-H460 cells. The results indicate that 15 exerts its antiproliferative activity by affecting microtubules and causing cell death subsequently to a mitotic arrest, and thus has the potential for antitumor activity.

CLEFMA Activates the Extrinsic and Intrinsic Apoptotic Processes through JNK1/2 and p38 Pathways in Human Osteosarcoma Cells

Due to the poor prognosis of metastatic osteosarcoma, chemotherapy is usually employed in the adjuvant situation to improve the prognosis and the chances of long-term survival. 4-[3,5-Bis(2-chlorobenzylidene)-4-oxo-piperidine-1-yl]-4-oxo-2-butenoic acid (CLEFMA) is a synthetic analog of curcumin and possesses anti-inflammatory and anticancer properties. To further obtain information regarding the apoptotic pathway induced by CLEFMA in osteosarcoma cells, microculture tetrazolium assay, annexin V-FITC/PI apoptosis staining assay, human apoptosis array, and Western blotting were employed. CLEFMA dose-dependently decreased the cell viabilities of human osteosarcoma U2OS and HOS cells and significantly induced apoptosis in human osteosarcoma cells. In addition to the effector caspase 3, CLEFMA significantly activated both extrinsic caspase 8 and intrinsic caspase 9 initiators. Moreover, CLEFMA increased the phosphorylation of extracellular signal-regulated protein kinases (ERK)1/2, c-Jun N-terminal kinases (JNK)1/2 and p38. Using inhibitors of JNK (JNK-in-8) and p38 (SB203580), CLEFMA’s increases of cleaved caspases 3, 8, and 9 could be expectedly suppressed, but they could not be affected by co-treatment with the ERK inhibitor (U0126). Conclusively, CLEFMA activates both extrinsic and intrinsic apoptotic pathways in human osteosarcoma cells through JNK and p38 signaling. These findings contribute to a better understanding of the mechanisms responsible for CLEFMA’s apoptotic effects on human osteosarcoma cells.

Potential multifunctional agents with anti-hepatoma and anti-inflammation properties by inhibiting NF-кB activation

Inhibition of NF-κB signalling has been demonstrated as a therapeutic option in treating inflammatory diseases and cancers. Herein, we synthesized novel dissymmetric 3,5-bis(arylidene)-4-piperidones (BAPs, 83-102) and characterized fully. MTT and ELISA assay were performed to screen the anti-hepatoma and anti-inflammation properties. 96 showed the most potential bioactivity. 96 could promote HepG2 apoptosis through up-regulating the expression of C-Caspase-3 and Bax, down-regulating the expression of Bcl-2, while markedly inhibit LPS or TNF-α-induced activation of NF-κB through both inhibiting the phosphorylation of IκBα and p65, and preventing the p65 nuclear translocation to exhibit both anti-hepatoma and anti-inflammatory activities. Molecular docking verified that simulated 96 can effectively bond to the active site of Bcl-2 and NF-κB/p65 proteins. 96 inhibited xenografts growth by reducing the expression of TNF-α and Bcl-2 in the tumour tissue. This study suggested that 96 could be developed as a potential multifunctional agent for treatment of inflammatory diseases and cancers.

Cocrystals and Salts of 3,5-Bis(pyridinylmethylene)piperidin-4-one with Aromatic Poly-Carboxylates and Resorcinols: Influence of Stacking Interactions on Solid-State Luminescence Properties

Two bis-pyridyl-substituted α,β-unsaturated ketones were shown to form complexes with carboxylic acids and resorcinol derivatives. The neutral acid–acid homosynthon was observed in only one complex out of the five acid-bis-pyridyl containing complexes studied here, while the –COO−⋯HOOC– synthon was found to be dominant as it was observed in four complexes. The carboxylates self-assembled to form discrete dimeric, anionic, 1D chains and also exhibited mixed ionic hydrogen bonds. On the other hand, resorcinol derivatives displayed O–H⋯N hydrogen bonding to form tetrameric aggregates of bis-pyridyl ketone molecules and respective co-formers, while 3,5-dihydroxy benzoic acid (DHBA) molecules formed 1D chains by clipping two molecules of ketones with three DHBA molecules. Such clipping by the resorcinol derivatives promoted continuous π–π stacking interactions. Consequently, these materials emitted at higher wavelengths compared with the parent bis-pyridyl-substituted α,β-unsaturated ketones.

Synthesis, antiproliferative activity and 2D-QSAR study of some 8-alkyl-2,4-bisbenzylidene-3-nortropinones

AIM

Colon cancer is the third leading cause of death worldwide; therefore, there is a need for an effective therapy with lower side effects.

METHODS

A series of 8-alkyl-2,4-bisbenzylidene-3-nortropinones 3 & 14-39 was prepared via Claisen-Schmidt condensation of 8-alkyl-3-nortropinones 11-13 with different aromatic aldehydes. The target compounds were screened for their antiproliferative activity.

RESULTS

Most of the prepared compounds showed promising antiproliferative activity against many of 60 National Cancer Institute cell lines at 10 μM. Furthermore, 8-ethyl-2,4-bis(3,4-dimethoxybenzylidene)-8-nortropin-3-one 29 and its 3,4,5-trimethoxy analog 30 were the most active compounds against HCT116 cell line with IC₅₀ values 0.01 and 0.46 μM, respectively. Using CODESSA-Pro software, a significant 2D-quantitative structure-activity relationship (QSAR) model was obtained.

CONCLUSION

The 8-Alkyl-2,4-bisbenzylidene-8-azabicyclo[3.2.1]octan-3-one represents an interesting core for further structural optimization to obtain more promising hits.

Synthesis, crystal structures and anti-inflammatory activity of four 3,5-bis(arylidene)-N-benzenesulfonyl-4-piperidone derivatives

3,5-Bis(arylidene)-4-piperidone (BAP) derivatives display good antitumour and anti-inflammatory activities because of their double α,β-unsaturated ketone structural characteristics. If N-benzenesulfonyl substituents are introduced into BAPs, the configuration of the BAPs would change significantly and their anti-inflammatory activities should improve. Four N-benzenesulfonyl BAPs, namely (3E,5E)-1-(4-methylbenzenesulfonyl)-3,5-bis[4-(trifluoromethyl)benzylidene]piperidin-4-one dichloromethane monosolvate, C₂₈H₂₁F₆NO₃S·CH₂Cl₂, (4), (3E,5E)-1-(4-fluorobenzenesulfonyl)-3,5-bis[4-(trifluoromethyl)benzylidene]piperidin-4-one, C₂₇H₁₈F₇NO₃S, (5), (3E,5E)-1-(4-nitrobenzenesulfonyl)-3,5-bis[4-(trifluoromethyl)benzylidene]piperidin-4-one, C₂₇H₁₈F₆N₂O₅S, (6), and (3E,5E)-1-(4-cyanobenzenesulfonyl)-3,5-bis[4-(trifluoromethyl)benzylidene]piperidin-4-one dichloromethane monosolvate, C₂₈H₁₈F₆N₂O₃S·CH₂Cl₂, (7), were prepared by Claisen-Schmidt condensation and N-sulfonylation. They were characterized by NMR, FT-IR and HRMS (high resolution mass spectrometry). Single-crystal structure analysis reveals that the two 4-(trifluoromethyl)phenyl rings on both sides of the piperidone ring in (4)-(7) adopt an E stereochemistry of the olefinic double bonds. Molecules of both (4) and (6) are connected by hydrogen bonds into one-dimensional chains. In (5) and (7), pairs of adjacent molecules embrace through intermolecular hydrogen bonds to form a bimolecular combination, which are further extended into a two-dimensional sheet. The anti-inflammatory activity data reveal that (4)-(7) significantly inhibit LPS-induced interleukin (IL-6) and tumour necrosis factor (TNF-α) secretion. Most importantly, (6) and (7), with strong electron-withdrawing substituents, display more potential inhibitory effects than (4) and (5).

Curcumin: A naturally occurring autophagy modulator

Autophagy is a self-degradative process that plays a pivotal role in several medical conditions associated with infection, cancer, neurodegeneration, aging, and metabolic disorders. Its interplay with cancer development and treatment resistance is complicated and paramount for drug design since an autophagic response can lead to tumor suppression by enhancing cellular integrity and tumorigenesis by improving tumor cell survival. In addition, autophagy denotes the cellular ability of adapting to stress though it may end up in apoptosis activation when cells are exposed to a very powerful stress. Induction of autophagy is a therapeutic option in cancer and many anticancer drugs have been developed to this aim. Curcumin as a hydrophobic polyphenol compound extracted from the known spice turmeric has different pharmacological effects in both in vitro and in vivo models. Many reports exist reporting that curcumin is capable of triggering autophagy in several cancer cells. In this review, we will focus on how curcumin can target autophagy in different cellular settings that may extend our understanding of new pharmacological agents to overcome relevant diseases.

The curcuminoid, EF-24, reduces cisplatin-mediated reactive oxygen species in zebrafish inner ear auditory and vestibular tissues

Cisplatin is a widely used chemotherapy drug that can damage auditory and vestibular tissue and cause hearing and balance loss through the intracellular release of reactive oxygen species (ROS). Curcumin has anticancer efficacy and can also counteract cisplatin's damaging effect against sensory tissue by scavenging intracellular ROS, but curcumin's applicability is limited due to its low bioavailability. EF-24 is a synthetic curcumin analog that is more bioavailable than curcumin and can target cancer, but its effects against cisplatin-mediated ROS in auditory and vestibular tissue is currently unknown. In this study, we employed a novel zebrafish inner ear tissue culture system to determine if EF-24 counteracted cisplatin-mediated ROS release in two sensory endorgans, the saccule and the utricle. The zebrafish saccule is associated with auditory function and the utricle with vestibular function. Trimmed endorgans were placed in tissue culture media with a fluorescent reactive oxygen species indicator dye, and intracellular ROS release was measured using a spectrophotometer. We found that cisplatin treatment significantly increased ROS compared to controls, but that EF-24 treatment did not alter or even decreased ROS. Importantly, when equimolar cisplatin and EF-24 treatments are combined, ROS did not increase compared to controls. This suggests that EF-24 may be able to prevent intracellular ROS caused by cisplatin treatment in inner ear tissue.

Ubiquitin Receptor RPN13 Mediates the Inhibitory Interaction of Diphenyldihaloketones CLEFMA and EF24 With the 26S Proteasome

The proteasome is a validated target in drug discovery for diseases associated with unusual proteasomal activity. Here we report that two diphenyldihaloketones, CLEFMA and EF24, inhibit the peptidase activity of the 26S proteasome. The objective of this study was to investigate interaction of these compounds with the proteasome and identify a putative target within the protein components of the 26S proteasome. We employed standard fluorogenic peptide-based proteasome activity assay for trypsin-like, chymotrypsin-like, and caspase-like activities of human purified 26S proteasome in cell-free conditions. GFPu-1 and HUVEC cells were used as proteasome reporter cells. Direct binding studies used purified 19S, 20S, 26S, and recombinant RPN13-Pru for interaction with biotinylated analogs of CLEFMA and EF24. The reaction mixtures were subjected to horizontal gel electrophoresis, streptavidin-blotting, pull-down assays, and immunoblotting. The identity of the interacting protein was determined by 2D gel electrophoresis and LC-MS/MS. Drug affinity responsive target stability technique was utilized to examine if CLEFMA binding confers protection to RPN13 against thermolysin-catalyzed proteolysis. We found that trypsin-and chymotrypsin-like activities of the 26S proteasome were reduced significantly by both compounds. The compounds also reduced the proteolytic activity in GFPu-1 and HUVEC cells, resulting in accumulation of ubiquitinated proteins without affecting the autophagy process. From direct binding assays a 43 kDa protein in the 26S proteasome was found to be the interacting partner. This protein was identified by tandem mass spectroscopy as regulatory particle subunit 13 (RPN13), a ubiquitin receptor in the 19S regulatory particle. Furthermore, binding of CLEFMA to RPN13 did not protect latter from thermolysin-mediated proteolysis. Together, this study showed diphenyldihaloketones as potential proteasome inhibitors for treatment of diseases with perturbed proteasome function. The results also unraveled RPN13 as a unique target of CLEFMA and EF24. As a result, these compounds inhibit both trypsin-like and chymotrypsin-like proteasome activities.

Induction of gut proteasome activity in hemorrhagic shock and its recovery by treatment with diphenyldihaloketones CLEFMA and EF24

Multiorgan failure in hemorrhagic shock is triggered by gut barrier dysfunction and consequent systemic infiltration of proinflammatory factors. Our previous study has shown that diphenyldihaloketone drugs 4-[3,5-bis[(2-chlorophenyl)methylene]-4-oxo-1-piperidinyl]-4-oxo-2-butenoic acid (CLEFMA) and 3,5-bis[(2-fluorophenyl)methylene]-4-piperidinone (EF24) restore gut barrier dysfunction and reduce systemic inflammatory response in hemorrhagic shock. We investigated the effect of hemorrhagic shock on proteasome activity of intestinal epithelium and how CLEFMA and EF24 treatments modulate proteasome function in hemorrhagic shock. CLEFMA or EF24 (0.4 mg/kg) were given 1 h after withdrawing 50% of blood from Sprague-Dawley rats; no other resuscitation was provided. After another 5 h of compensation, small gut was collected to process tissue for proteasome activity, immunoblotting, and mRNA levels of genes responsible for unfolded-protein response (XBP1, ATF4, glucose-regulated protein of 78/95 kDa, and growth arrest and DNA damage inducible genes 153/34), polyubiquitin B and C, and immunoproteasome subunits β type-8 and -10 and proteasome activator subunit 1. We found that hemorrhagic shock induced proteasome activity in gut tissue and reduced the amounts of ubiquitinated proteins displayed on antiubiquitin immunoblots. However, simultaneous induction of unfolded-protein response or immunoproteasome genes was not observed. CLEFMA and EF24 treatments abolished the hemorrhagic shock-induced increase in proteasome activity. Further investigations revealed that the induction of proteasome in hemorrhagic shock is associated with disassembly of 26S proteasome; CLEFMA and EF24 prevented this disassembly. Consistent with these data, CLEFMA and EF24 reduced hemorrhagic shock-induced degradation of 20S substrate ornithine decarboxylase in gut tissue. These results suggest that activated proteasome plays an important role in ischemic gut pathophysiology, and it can be a druggable target in shock-induced gut dysfunction. NEW & NOTEWORTHY Ischemic injury to the gut is a trigger for the systemic inflammatory response and multiple organ failure in trauma and hemorrhagic shock. We show for the first time that hemorrhagic shock induces the gut proteasome activity by engendering 26S proteasome disassembly. Diphenyldihaloketones 4-[3,5-bis[(2-chlorophenyl)methylene]-4-oxo-1-piperidinyl]-4-oxo-2-butenoic acid and 3,5-bis[(2-fluorophenyl)methylene]-4-piperidinone treatment prevented the 26S disassembly. Understanding the role of proteasome in shock-associated gut injury will assist in the development of therapeutic means to address it.

Novel asymmetric 3,5-bis(arylidene)piperidin-4-one derivatives: synthesis, crystal structures and cytotoxicity

3,5-Bis(arylidene)piperidin-4-one derivatives (BAPs) display good antitumour activity because of their double α,β-unsaturated ketone structural characteristics. Reported BAPs have generally been symmetric and asymmetric BAPs have been little documented. Three asymmetric BAPs, namely (5E)-3-(4-tert-butylbenzylidene)-5-(4-fluorobenzylidene)-1-methylpiperidin-4-one, C₂₄H₂₆FNO, (5), (5E)-3-(4-tert-butylbenzylidene)-5-(3,5-dimethoxybenzylidene)-1-methylpiperidin-4-one, C₂₆H₃₁NO₃, (6), and (5E)-3-{3-[(E)-(2,3-dihydroxybenzylidene)amino]benzylidene}-5-(2-fluorobenzylidene)-1-methylpiperidin-4-one, C₂₇H₂₃FN₂O₃, (12), were generated by Claisen-Schmidt condensation. They are characterized by NMR and FT-IR spectroscopies, and elemental analysis. Single-crystal structure analysis reveals that the two arylidene rings on both sides of the BAP structures adopt an E stereochemistry of the olefinic double bonds and the compounds are E,E isomers. Molecules of (5) and (12) generate one-dimensional chains through intermolecular hydrogen bonds, while compound (6) generates a two-dimensional network through hydrogen bonds. Preliminary cytotoxicities toward human liver hepatocellular carcinoma cell line (HepG2), human acute mononuclear granulocyte leukaemia (THP-1) and human normal hepatical cell line (LO2) were evaluated.

Novel dissymmetric 3,5-bis(arylidene)-4-piperidones as potential antitumor agents with biological evaluation in vitro and in vivo

Thirty-five novel dissymmetric 3,5-bis(arylidene)-4-piperidone derivatives (BAPs, 6a-h, 7a-h, 8a-g, 9a-g, 10a-e) were synthesized and evaluated the cytotoxicity. BAPs 6d, 7h, 8g, 9g demonstrated the most potentially inhibitory activities against HepG2 and THP-1 but lower cytotoxicity toward LO2. In vitro, 6d, 7h, 8g, 9g can effectively up-regulate BAX expression, down-regulate Bcl-2 expression in HepG2 cell. They could reasonably bind to the active site of Bcl-2 protein proved by molecular docking modes. The most active BAP 6d induced HepG2 cells apoptosis in a dose-dependent manner by flow cytometrey. The cellular uptake of HepG2 cells showed 6d mainly accumulated into the nuclei by confocal laser scanning microscopy (CLSM). In vivo, 6d suppressed the growth of HepG2 xenografts in nude mice and relatively nontoxic to mice. These results suggest that 6d could be therapeutically beneficial as potential therapeutic agent for the early clinical treatment of liver cancers.

Synthesis and anti-tumor activity of EF24 analogues as IKKβ inhibitors

EF24 is an IKKβ inhibitor (IC₅₀: 72 μM) containing various anti-tumor activities. In this study, a series of EF24 analogs targeting IKKβ were designed and synthesized. Several IKKβ inhibitors with better activities than EF24 were screened out and B3 showed best IKKβ inhibitory (IC₅₀: 6.6 μM). Molecular docking and dynamic simulation experiments further confirmed this inhibitory effect. B3 obviously suppressed the viability of Hela229, A549, SGC-7901 and MGC-803 cells. Then, in SGC-7901 and MGC-803 cells, B3 blocked the NF-κB signal pathway by inhibiting IKKβ phosphorylation, and followed arrested the cell cycle at G2/M phase by suppressing the Cyclin B1 and Cdc2 p34 expression, induced the cell apoptosis by down-regulating Bcl-2 protein and up-regulating cleaved-caspase3. Moreover, B3 significantly reduced tumor growth and suppressed the IKKβ-NF-κB signal pathway in SGC-7901 xenograft model. In total, this study present a potential IKKβ inhibitor as anti-tumor precursor.

Modification of proteins and polysaccharides using dodecenyl succinic anhydride: Synthesis, properties and applications-A review

Proteins and polysaccharides are among the biopolymers produced by living organisms for their structural integrity, protection, physiological functions, or as reserve energy. These biopolymers are extracted from their natural matrices by humans to fulfil basic as well as convenience needs. The inquisitive human nature, ever-growing demands and resources at disposal have led to copious research in the field of biopolymer modifications. The availability of reactive sites on these biopolymers make them suitable substrates for esterification, etherification, oxidation, epoxidation, N-acylation, alkylation, etc. Dodecenyl succinic anhydride (DDSA) is an esterifying agent that introduces a 12-carbon hydrophobic chain in the structure of the substrate containing suitable reactive sites. The use of DDSA as a modifying agent for biopolymers dates back to the mid-twentieth century. Even today, many biopolymers are explored for modification with DDSA for improved functionality. These modifications are aimed at catering the needs of the paint, pharmaceutical, cosmetic, food and textile industries. This review attempts to systematically compile reported research on the use of DDSA as a biopolymer modifying agent, the various reaction techniques, properties and applications thereof.

Mannich Curcuminoids as Potent Anticancer Agents

A series of novel curcuminoids were synthesised for the first time via a Mannich-3CR/organocatalysed Claisen-Schmidt condensation sequence. Structure-activity relationship (SAR) studies were performed by applying viability assays and holographic microscopic imaging to these curcumin analogues for anti-proliferative activity against A549 and H1975 lung adenocarcinoma cells. The TNFα-induced NF-κB inhibition and autophagy induction effects correlated strongly with the cytotoxic potential of the analogues. Significant inhibition of tumour growth was observed when the most potent analogue 44 was added in liposomes at one-sixth of the maximally tolerated dose in the A549 xenograft model. The novel spectrum of activity of these Mannich curcuminoids warrants further preclinical investigations.

Structure based comprehensive modelling, spatial fingerprints mapping and ADME screening of curcumin analogues as novel ALR2 inhibitors

Aldose reductase (ALR2) inhibition is the most legitimate approach for the management of diabetic complications. The limited triumph in the drug development against ALR2 is mainly because of its close structural similarity with the other members of aldo-keto reductase (AKR) superfamily viz. ALR1, AKR1B10; and lipophilicity problem i.e. poor diffusion of synthetic aldose reductase inhibitors (ARIs) to target tissues. The literature evidenced that naturally occurring curcumin demonstrates relatively specific and non-competitive inhibition towards human recombinant ALR2 over ALR1 and AKR1B10; however β-diketone moiety of curcumin is a specific substrate for liver AKRs and accountable for it’s rapid in vivo metabolism. In the present study, structure based comprehensive modelling studies were used to map the pharmacophoric features/spatial fingerprints of curcumin analogues responsible for their ALR2 specificity along with potency on a data set of synthetic curcumin analogues and naturally occurring curcuminoids. The data set molecules were also screened for drug-likeness or ADME parameters, and the screening data strongly support that curcumin analogues could be proposed as a good drug candidate for the development of ALR2 inhibitors with improved pharmacokinetic profile compared to curcuminoids due to the absence of β-diketone moiety in their structural framework.

Role of Autophagy and Apoptosis in Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) constitutes 85% of all lung cancers, and is the leading cause of cancer-related death worldwide. The poor prognosis and resistance to both radiation and chemotherapy warrant further investigation into the molecular mechanisms of NSCLC and the development of new, more efficacious therapeutics. The processes of autophagy and apoptosis, which induce degradation of proteins and organelles or cell death upon cellular stress, are crucial in the pathophysiology of NSCLC. The close interplay between autophagy and apoptosis through shared signaling pathways complicates our understanding of how NSCLC pathophysiology is regulated. The apoptotic effect of autophagy is controversial as both inhibitory and stimulatory effects have been reported in NSCLC. In addition, crosstalk of proteins regulating both autophagy and apoptosis exists. Here, we review the recent advances of the relationship between autophagy and apoptosis in NSCLC, aiming to provide few insights into the discovery of novel pathogenic factors and the development of new cancer therapeutics.

Stability study on an anti-cancer drug 4-(3,5-bis(2-chlorobenzylidene)-4-oxo-piperidine-1-yl)-4-oxo-2-butenoic acid (CLEFMA) using a stability-indicating HPLC method

CLEFMA, 4-(3,5-bis(2-chlorobenzylidene)-4-oxo-piperidine-1-yl)-4-oxo-2-butenoic acid, is a new chemical entity with anti-cancer and anti-inflammatory activities. Here, we report its stability in solution against stress conditions of exposure to acid/base, light, oxidant, high temperature, and plasma. The identity of the degradation products was ascertained by mass and proton nuclear magnetic resonance spectroscopy. To facilitate this study, we developed and validated a reverse phase high performance liquid chromatography method for detection of CLEFMA and its degradation. The method was linear over a range of 1–100 µg/mL; the accuracy and precision were within acceptable limits; it was stability-indicating as it successfully separated cis-/trans-isomers of CLEFMA as well as its degradation product. The major degradation product was produced from amide hydrolysis at maleic acid functionality caused by an acidic buffer, oxidant (3% hydrogen peroxide), or temperature stress (40–60 °C). The log k-pH profile showed that CLEFMA was most stable at neutral pH. In accelerated stability study we found that the shelf-life (T_90%) of CLEFMA at 25 °C and 4 °C was 45 days and 220 days, respectively. Upon exposure to UV-light (365 nm), the normally prevalent trans-CLEFMA attained cis-configuration. This isomerization also involved the maleic acid moiety. CLEFMA was stable in plasma from which it could be efficiently extracted by an acetonitrile precipitation method. These results indicate that CLEFMA is sensitive to hydrolytic cleavage at its maleic acid moiety, and it is recommended that its samples should be stored under refrigerated and light-free conditions, and under inert environment.

Synthesis, Anticancer Activity and Cytotoxicity of Novel Double Schiff-Base Condensed α,β-Unsaturated Keto Derivatives

Five double Schiff-base condensed α,β-unsaturated keto derivatives, as curcumin analogues, were synthesised in three steps. Cyclohexanone, or N-methyl-4-pyridone, and 3-nitrobenzaldehyde (2 equiv.) were subjected to Claisen-Schmidt condensation under acid conditions to yield tricyclic dinitro compounds which were reduced to the corresponding diamines and then derivatised at their amino groups with 1-aryl(alkyl)-butan-1,3-diones (MeCOCH2COR). Anticancer activities of the five compounds against four human carcinoma cell lines and their cytotoxicities for LO2 cell lines were evaluated by the MTT method. All compounds showed moderate anticancer activity and low cytotoxicity. The single N-methyl-4-piperidinone-derived compound that was synthesised displayed the highest anticancer activity toward THP-1 and the lowest cytotoxicity.

Modulation of P-glycoprotein activity by novel synthetic curcumin derivatives in sensitive and multidrug-resistant T-cell acute lymphoblastic leukemia cell lines

BACKGROUND

Multidrug resistance (MDR) and drug transporter P-glycoprotein (P-gp) represent major obstacles in cancer chemotherapy. We investigated 19 synthetic curcumin derivatives in drug-sensitive acute lymphoblastic CCRF-CEM leukemia cells and their multidrug-resistant P-gp-overexpressing subline, CEM/ADR5000.

MATERIAL AND METHODS

Cytotoxicity was tested by resazurin assays. Doxorubicin uptake was assessed by flow cytometry. Binding modes of compounds to P-gp were analyzed by molecular docking. Chemical features responsible for bioactivity were studied by quantitative structure activity relationship (QSAR) analyses. A 7-descriptor QSAR model was correlated with doxorubicin uptake values, IC50 values and binding energies.

RESULTS

The compounds displayed IC50 values between 0.7±0.03 and 20.2±0.25μM. CEM/ADR5000 cells exhibited cross-resistance to 10 compounds, collateral sensitivity to three compounds and regular sensitivity to the remaining six curcumins. Molecular docking studies at the intra-channel transmembrane domain of human P-gp resulted in lowest binding energies ranging from -9.00±0.10 to -6.20±0.02kcal/mol and pKi values from 0.24±0.04 to 29.17±0.88μM. At the ATP-binding site of P-gp, lowest binding energies ranged from -9.78±0.17 to -6.79±0.01kcal/mol and pKi values from 0.07±0.02 to 0.03±0.03μM. CEM/ADR5000 cells accumulated approximately 4-fold less doxorubicin than CCRF-CEM cells. The control P-gp inhibitor, verapamil, partially increased doxorubicin uptake in CEM/ADR5000 cells. Six curcumins increased doxorubicin uptake in resistant cells or even exceeded uptake levels compared to sensitive one. QSAR yielded good activity prediction (R=0.797 and R=0.794 for training and test sets).

CONCLUSION

Selected derivatives may serve to guide future design of novel P-gp inhibitors and collateral sensitive drugs to combat MDR.

Discovery of monocarbonyl curcumin hybrids as a novel class of human DNA ligase I inhibitors: in silico design, synthesis and biology

A pharmacophore model identified a novel class of hLigI inhibitors to treat cancer. 36 compounds were synthesized and the identified inhibitor, compound 23 shown antiligase activity at IC₅₀ 24.9 μM by abolishing the interaction between hLigI and DNA.