Curcumin suppresses the dynamic instability of microtubules, activates the mitotic checkpoint and induces apoptosis in MCF-7 cells

Harnessing curcumin and nanotechnology for enhanced treatment of breast cancer bone metastasis

Breast cancer (BC) bone metastasis poses a significant clinical challenge due to its impact on patient prognosis and quality of life. Curcumin (CUR), a natural polyphenol compound found in turmeric, has shown potential in cancer therapy due to its anti-inflammatory, antioxidant, and anticancer properties. However, its metabolic instability and hydrophobicity have hindered its clinical applications, leading to a short plasma half-life, poor absorption, and low bioavailability. To enhance the drug-like properties of CUR, nanotechnology-based delivery strategies have been employed, utilizing polymeric, lipidic, and inorganic nanoparticles (NPs). These approaches have effectively overcome CUR's inherent limitations by enhancing its stability and cellular bioavailability both in vitro and in vivo. Moreover, targeting molecules with high selectivity towards bone metastasized breast cancer cells can be used for site specific delivery of curcumin. Alendronate (ALN), a bone-seeking bisphosphonate, is one such moiety with high selectivity towards bone and thus can be effectively used for targeted delivery of curcumin loaded nanocarriers. This review will detail the process of bone metastasis in BC, elucidate the mechanism of action of CUR, and assess the efficacy of nanotechnology-based strategies for CUR delivery. Specifically, it will focus on how these strategies enhance CUR's stability and improve targeted delivery approaches in the treatment of BC bone metastasis.

Modulatory Effects of Biosynthesized Gold Nanoparticles Conjugated with Curcumin and Paclitaxel on Tumorigenesis and Metastatic Pathways-In Vitro and In Vivo Studies

Background: Breast cancer is the most common cancer in women globally, and diagnosing it early and finding potential drug candidates against multi-drug resistant metastatic breast cancers provide the possibilities of better treatment and extending life. Methods: The current study aimed to evaluate the synergistic anti-metastatic activity of Curcumin (Cur) and Paclitaxel (Pacli) individually, the combination of Curcumin–Paclitaxel (CP), and also in conjugation with gold nanoparticles (AuNP–Curcumin (Au-C), AuNP–Paclitaxel (Au-P), and AuNP–Curcumin–Paclitaxel (Au-CP)) in various in vitro and in vivo models. Results: The results from combination treatments of CP and Au-CP demonstrated excellent synergistic cytotoxic effects in triple-negative breast cancer cell lines (MDA MB 231 and 4T1) in in vitro and in vivo mouse models. Detailed mechanistic studies were performed that reveal that the anti-cancer effects were associated with the downregulation of the expression of VEGF, CYCLIN-D1, and STAT-3 genes and upregulation of the apoptotic Caspase-9 gene. The group of mice that received CP combination therapy (with and without gold nanoparticles) showed a significant reduction in the size of tumor when compared to the Pacli alone treatment and control groups. Conclusions: Together, the results suggest that the delivery of gold conjugated Au-CP formulations may help in modulating the outcomes of chemotherapy. The present study is well supported with observations from cell-based assays, molecular and histopathological analyses.

Vanadocene dichloride induces apoptosis in HeLa cells through depolymerization of microtubules and inhibition of Eg5

Vanadocene dichloride (VDC), a vanadium containing metallocene dihalide exhibits promising anticancer activity. However, its mechanism of action remains elusive as several diverse targets and pathways have been proposed for its anticancer activity. In this study, we observed that VDC inhibited the proliferation of mammalian cancer cells and induced apoptotic cell death by altering the mitochondrial membrane potential and the expression of bcl2 and bax. Probing further into its anticancer mechanism, we found that VDC caused depolymerization of interphase microtubules and blocked the cells at mitosis with considerable proportion of cells exhibiting monopolar spindles. The reassembly of cold depolymerized microtubules was strongly inhibited in the presence of 10 μM VDC. VDC perturbed the microtubule-kinetochore interactions during mitosis as indicated by the absence of cold stable spindle microtubules in the cells treated with 20 μM VDC. Using goat brain tubulin, we found that VDC inhibited the steady-state polymer mass of microtubules and bound to tubulin at a novel site with a K_d of 9.71 ± 0.19 μM and perturbed the secondary structure of tubulin dimer. In addition, VDC was also found to bind to the mitotic kinesin Eg5 and inhibit its basal as well as microtubule stimulated ATPase activity. The results suggest that disruption of microtubule assembly dynamics and inhibition of the ATPase activity of Eg5 could be a plausible mechanism for the antiproliferative and antimitotic activity of VDC.Graphic abstract.

Paclitaxel-Based Chemotherapy Targeting Cancer Stem Cells from Mono- to Combination Therapy

Paclitaxel (PTX) is a chemotherapeutical agent commonly used to treat several kinds of cancer. PTX is known as a microtubule-targeting agent with a primary molecular mechanism that disrupts the dynamics of microtubules and induces mitotic arrest and cell death. Simultaneously, other mechanisms have been evaluated in many studies. Since the anticancer activity of PTX was discovered, it has been used to treat many cancer patients and has become one of the most extensively used anticancer drugs. Regrettably, the resistance of cancer to PTX is considered an extensive obstacle in clinical applications and is one of the major causes of death correlated with treatment failure. Therefore, the combination of PTX with other drugs could lead to efficient therapeutic strategies. Here, we summarize the mechanisms of PTX, and the current studies focusing on PTX and review promising combinations.

Focus on Multi-targeted Role of Curcumin: a Boon in Therapeutic Paradigm

Curcumin is a polyphenolic compound that exhibited good anticancer potential against different types of cancers through its multi-targeted effect like the termination of cell proliferation, inflammation, angiogenesis, and metastasis, thereby acting as antiproliferative and cytotoxic in nature. The present review surveys the various drug combination tried with curcumin or its synthetic analogues and also the mechanism by which curcumin potentiates the effect of almost every drug. In addition, this article also focuses on aromatherapy which is gaining much popularity in cancer patients. After thoroughly studying several articles on combination therapy of curcumin through authenticated book chapters, websites, research, and review articles available at PubMed, ScienceDirect, etc., it has been observed that multi-targeted curcumin possess enormous anticancer potential and, with whatever drug it is given in combination, has always resulted in enhanced effect with reduced dose as well as side effects. It is also capable enough in overcoming the problem of chemoresistance. Besides this, aromatherapy also proved its potency in reducing cancer-related side effects. Combining all the factors together, we can conclude that combination therapy of drugs with curcumin should be explored extensively. In addition, aromatherapy can be used as an adjuvant or supplementary therapy to reduce the cancer complications in patients.

Co-delivery of paclitaxel and curcumin by biodegradable polymeric nanoparticles for breast cancer chemotherapy

Multi-drug chemotherapy has been one of the most popular strategies for the treatment of malignant tumors, and has achieved desirable therapeutic outcomes. The objective of the present study is to develop biodegradable PCEC nanoparticles (NPs) for the co-delivery of paclitaxel (PTX) and curcumin (CUR), and investigate the antitumor effect of the drug delivery system (DDS: PTX-CUR-NPs) against breast cancer both in vitro and in vivo. The prepared PTX-CUR-NPs had a small size of 27.97 ± 1.87 nm with a low polydispersity index (PDI, 0.197 ± 0.040). The results exhibited slow release of PTX and CUR from the DDS without any burst effect. Further, the PTX-CUR-NPs displayed a dose-dependent cytotoxicity in MCF-7 cells with a higher apoptosis rate (64.29% ± 1.97%) as compared to that of free drugs (PTX + CUR, 34.21% ± 0.81%). The cellular uptake study revealed that the drug loaded PCEC polymeric nanoparticles were more readily uptaken by tumor cells in vitro. To evaluate the in vivo anti-tumor effect, the PTX-CUR-NPs were intravenously administered to BALB/c nude mouse xenografted with MCF-7 cells and the results exhibited significant inhibition of tumor growth with prolonged survival time and reduced side effect when compared with free drugs (PTX + CUR). Moreover, the administration of PTX-CUR-NPs treatment led to lower Ki67 expression (p < 0.05), and enhanced TUNEL positivity (higher apoptosis, p < 0.01) in tumor cells as compared to other treatment groups, suggesting the therapeutic efficacy of the DDS. Altogether, the present study suggests that the DDS PTX-CUR-NPs could be employed for the effective treatment of breast cancers in near future.

RGD peptide-mediated liposomal curcumin targeted delivery to breast cancer cells

In this study, turmeric's active ingredient (Curcumin) was encapsulated into RGD modified Liposomes (RGD-Lip-Cur) its cytotoxic effect on the breast cancer cell line (MCF-7) was evaluated by MTT, flow cytometry and Caspase assay. Liposomes were characterized using transmission electron microscopy (TEM). Results demonstrated that the liposomes were spherical in shape, ranging from 70 to 100 nm. MTT assay revealed that RGD-Lip-Cur had a significant cytotoxic effect on MCF-7 cells at concentrations of 32, 16 and 4 μg/ml compared to Lip-Cur (P < 0.05) and curcumin (P < 0.01). The apoptosis assay demonstrated that RGD-Lip-Cur induces the apoptosis in MCF-7 cells (39.6% vs 40.2% for initial and secondary apoptosis) significantly more than Lip-Cur (67.7% vs 9.16% for initial and secondary apoptosis) and free curcumin (7.84% vs 38.8% for initial and secondary apoptosis). Moreover, caspase assay showed that RGD-Lip-Cur activates caspase 3/7 compared to Lip-Cur (P < 0.05) and free curcumin (P < 0.01). The RGD-Lip-Cur was similar to the control group and had no significant cytotoxicity effect. It is concluded that RGD-Lip-Cur as a novel carrier have high cytotoxicity effect on breast cancer cell line (MCF-7).

Coffea arabica Bean Extracts and Vitamin C: A Novel Combination Unleashes MCF-7 Cell Death

BACKGROUND

Vitamin C (VC) is believed to enhance immunity and is regularly integrated as a supplementary agent during several treatments.

OBJECTIVE

The green (GC) and roasted (RC) coffee (Coffea arabica) aqueous extracts (0, 125, 250 and 500 μg/ml) combined with VC (50 μg/ml) were examined on the cancerous MCF-7 cell line and normal human lymphocytes.

METHODS

Neutral red uptake assay, comet assay, immunocytochemical reactivity for protein expression and mRNA expression of apoptosis-related genes were performed.

RESULTS

A significant (P< 0.05) concentration-dependent increase of apoptotic features, such as morphological changes, and abundant nuclear condensation, altered the expression of p53 and caspase-3 mRNA, down-regulation of Bcl-2 protein as well as the acidic autophagosomal vacuolization in treated cells. The oxidative stress and DNA single-strand breaks were noticed too.

CONCLUSION

These results suggest that coffee in combination with VC undergoes apoptotic anticancer pathway. This supports the integration of coffee and VC as a valuable candidate for anticancer research and treatments.

Highlighting Curcumin-Induced Crosstalk between Autophagy and Apoptosis as Supported by Its Specific Subcellular Localization

Curcumin, a major active component of turmeric (Curcuma longa, L.), is known to have various effects on both healthy and cancerous tissues. In vitro studies suggest that curcumin inhibits cancer cell growth by activating apoptosis, but the mechanism underlying the anticancer effect of curcumin is still unclear. Since there is a recent consensus about endoplasmic reticulum (ER) stress being involved in the cytotoxicity of natural compounds, we have investigated using Image flow cytometry the mechanistic aspects of curcumin's destabilization of the ER, but also the status of the lysosomal compartment. Curcumin induces ER stress, thereby causing an unfolded protein response and calcium release, which destabilizes the mitochondrial compartment and induce apoptosis. These events are also associated with secondary lysosomal membrane permeabilization that occurs later together with an activation of caspase-8, mediated by cathepsins and calpains that ended in the disruption of mitochondrial homeostasis. These two pathways of different intensities and momentum converge towards an amplification of cell death. In the present study, curcumin-induced autophagy failed to rescue all cells that underwent type II cell death following initial autophagic processes. However, a small number of cells were rescued (successful autophagy) to give rise to a novel proliferation phase.

Anticancer activity of synthetic (±)-kusunokinin and its derivative (±)-bursehernin on human cancer cell lines

Kusunokinin is a potent lignan compound with a several biological properties including antitrypanosomal and anticancer. In this study, (±)-kusunokinin and its derivative, (±)-bursehernin, were synthesized and investigated for their anticancer activities on cell viability, cell cycle arrest and apoptosis in cancer cell lines including breast cancer (MCF-7, MDA-MB-468 and MDA-MB-231), colon cancer (HT-29) and cholangiocarcinoma (KKU-K100, KKU-M213 and KKU-M055) cells. The result showed that (±)-kusunokinin and (±)-bursehernin represented the strongest growth inhibition against breast cancer (MCF-7) and cholangiocarcinoma (KKU-M213) cells with the IC₅₀ values of 4.30 ± 0.65 μM and 3.70 ± 0.79 μM, respectively, both of which were lower than IC₅₀ of normal fibroblast cells (L929). Etoposide was used as a positive control since this chemotherapeutic drug is in the lignan group same as (±)-kusunokinin. Surprisingly, etoposide showed less cytotoxicity than (±)-kusunokinin and its derivative on MCF-7, HT-29, KKU-M213 and KKU-K100. Moreover, (±)-bursehernin induced cell cycle arrest at G2/M phase, meanwhile (±)-kusunokinin tended to increased cell population at G2/M phase but did not show the significant difference compared with non-treated cells. Interestingly, protein levels related to cell proliferation pathway (topoisomerase II, STAT3, cyclin D1, and p21) were significantly decreased at 72 h. Both compounds induced apoptotic cell in time-dependent manner as confirmed by MultiCaspase assay. In conclusion, synthetic compound, (±)-kusunokinin and (±)-bursehernin, showed anticancer effects via the reduction of cell proliferation proteins and induction of apoptosis.

Analyzing bioactive effects of the minor hop compound xanthohumol C on human breast cancer cells using quantitative proteomics

Minor prenylated hop compounds have been attracting increasing attention due to their promising anticarcinogenic properties. Even after intensive purification from natural raw extracts, allocating certain activities to single compounds or complex interactions of the main compound with remaining impurities in very low concentration is difficult. In this study, dose-dependent antiproliferative and cytotoxic effects of the promising xanthohumol (XN) analogue xanthohumol C (XNC) were evaluated and compared to XN and a XN-enriched hop extract (XF). It was demonstrated that the cell growth inhibition of human breast cancer cell line (MCF-7) significantly increases after being treated with XNC compared to XN and XF. Based on label-free data-dependent acquisition proteomics, physiological influences on the proteome of MCF-7 cells were analyzed. Different modes of action between XNC and XN treated MCF-7 cells could be postulated. XNC causes ER stress and seems to be involved in cell-cell adhesion, whereas XN influences cell cycles and DNA replication as well as type I interferon signaling pathway. The results demonstrate the utility of using quantitative proteomics for bioactivity screenings of minor hop compounds and underscore the importance of isolating highly pure compounds into their distinct forms to analyze their different and possibly synergistic activities and modes of action.

Synthetic resveratrol-curcumin hybrid derivative inhibits mitosis progression in estrogen positive MCF-7 breast cancer cells

Curcumin (1) and resveratrol (2) are bioactive natural compounds that display wide pharmacological properties, including antitumor activity. However, their clinical application has been limited due to their low solubility and bioavailability. Nevertheless, independent studies have considered these compounds as interesting prototypes for developing new chemical structures useful for anticancer therapy. Here in, we report the synthesis of novel curcumin-like hydrazide analogues (3a and 3b), and a series of curcumin-resveratrol hybrid compounds (4a-f), and the evaluation of their cytotoxic potential on three tumor cell lines MCF-7 (breast), A549 (lung), and HepG2 (liver). Cell viability was significantly reduced in all tested cell lines when compounds 4c-4e were used. The IC50 values for these compounds on MCF-7 cells were lower than those for curcumin, resveratrol, or curcumin combined with resveratrol. We evidenced that 4c promoted a drastic increase of G2/M population. The accumulation of cells in mitosis onset in treated cultures was due to, at least in part, the ability of 4c to modulate nuclear kinase proteins, which orchestrate important events in mitosis progression. We have also observed significant reduction of the relative RNAm abundance of CCNB1, PLK1, AURKA, AURKB in samples treated with 4c, with concomitant increase of CDKN1A (p21). Thus, compound 4c is a promising multi-target antitumor agent that should be considered for further in vivo studies.

Molecular Mechanisms Underlying Curcumin-Mediated Therapeutic Effects in Type 2 Diabetes and Cancer

The growing prevalence of age-related diseases, especially type 2 diabetes mellitus (T2DM) and cancer, has become global health and economic problems. Due to multifactorial nature of both diseases, their pathophysiology is not completely understood so far. Compelling evidence indicates that increased oxidative stress, resulting from an imbalance between production of reactive oxygen species (ROS) and their clearance by antioxidant defense mechanisms, as well as the proinflammatory state contributes to the development and progression of the diseases. Curcumin (CUR; diferuloylmethane), a well-known polyphenol derived from the rhizomes of turmeric Curcuma longa, has attracted a great deal of attention as a natural compound with beneficial antidiabetic and anticancer properties, partly due to its antioxidative and anti-inflammatory actions. Although this polyphenolic compound is increasingly being recognized for its growing number of protective health effects, the precise molecular mechanisms through which it reduces diabetes- and cancer-related pathological events have not been fully unraveled. Hence, CUR is the subject of intensive research in the fields Diabetology and Oncology as a potential candidate in the treatment of both T2DM and cancer, particularly since current therapeutic options for their treatment are not satisfactory in clinics. In this review, we summarize the recent progress made on the molecular targets and pathways involved in antidiabetic and anticancer activities of CUR that are responsible for its beneficial health effects.

Kinesin superfamily: roles in breast cancer, patient prognosis and therapeutics

Breast cancer pathobiology is known to be influenced by the differential expression of a group of proteins called the kinesin superfamily (KIFs), which is instrumental in the intracellular transport of chromosomes along microtubules during mitosis. During cellular division, kinesins are strictly regulated through temporal synthesis so that they are present only when needed. However, their misregulation may contribute to uncontrolled cell growth owing to premature sister chromatid separation, highlighting their importance in cancer. This review covers the functions of kinesins in normal and breast cancer cells, the use of kinesins for breast cancer patient prognosis, and the targeting of these molecules for therapeutics. A better understanding of KIF proteins may be pivotal to improved disease outcomes for breast cancer patients.

Lessons from bacterial homolog of tubulin, FtsZ for microtubule dynamics

FtsZ, a homolog of tubulin, is found in almost all bacteria and archaea where it has a primary role in cytokinesis. Evidence for structural homology between FtsZ and tubulin came from their crystal structures and identification of the GTP box. Tubulin and FtsZ constitute a distinct family of GTPases and show striking similarities in many of their polymerization properties. The differences between them, more so, the complexities of microtubule dynamic behavior in comparison to that of FtsZ, indicate that the evolution to tubulin is attributable to the incorporation of the complex functionalities in higher organisms. FtsZ and microtubules function as polymers in cell division but their roles differ in the division process. The structural and partial functional homology has made the study of their dynamic properties more interesting. In this review, we focus on the application of the information derived from studies on FtsZ dynamics to study microtubule dynamics and vice versa. The structural and functional aspects that led to the establishment of the homology between the two proteins are explained to emphasize the network of FtsZ and microtubule studies and how they are connected.

Curcumin alters the cytoskeleton and microtubule organization on trophozoites of Giardia lamblia

Giardia lamblia is a worldwide protozoan responsible for a significant number of intestinal infections. There are several drugs for the treatment of giardiasis, but they often cause side effects. Curcumin, a component of turmeric, has antigiardial activity; however, the molecular target and mechanism of antiproliferative activity are not clear. The effects of curcumin on cellular microtubules have been widely investigated. Since tubulin is the most abundant protein in the cytoskeleton of Giardia, to elucidate whether curcumin has activity against the microtubules of this parasite, we treated trophozoites with curcumin and the cells were analyzed by scanning electron microscopy and confocal microscopy. Curcumin inhibited Giardia proliferation and adhesion in a time-concentration-dependent mode. The higher inhibitory concentrations of curcumin (3 and 15μM) disrupted the cytoskeletal structures of trophozoites; the damage was evident on the ventral disk, flagella and in the caudal region, also the membrane was affected. The immunofluorescence images showed altered distribution of tubulin staining on ventral disk and flagella. Additionally, we found that curcumin caused a clear reduction of tubulin expression. By docking analysis and molecular dynamics we showed that curcumin has a high probability to bind at the interface of the tubulin dimer close to the vinblastine binding site. All the data presented indicate that curcumin may inhibit Giardia proliferation by perturbing microtubules.

Curcumin: the spicy modulator of breast carcinogenesis

Worldwide breast cancer is the most common cancer in women. For many years clinicians and the researchers are examining and exploring various therapeutic modalities for breast cancer. Yet the disease has remained unconquered and the quest for cure is still going on. Present-day strategy of breast cancer therapy and prevention is either combination of a number of drugs or a drug that modulates multiple targets. In this regard natural products are now becoming significant options. Curcumin exemplifies a promising natural anticancer agent for this purpose. This review primarily underscores the modulatory effect of curcumin on the cancer hallmarks. The focus is its anticancer effect in the complex pathways of breast carcinogenesis. Curcumin modulates breast carcinogenesis through its effect on cell cycle and proliferation, apoptosis, senescence, cancer spread and angiogenesis. Largely the NFkB, PI3K/Akt/mTOR, MAPK and JAK/STAT are the key signaling pathways involved. The review also highlights the curcumin mediated modulation of tumor microenvironment, cancer immunity, breast cancer stem cells and cancer related miRNAs. Using curcumin as a therapeutic and preventive agent in breast cancer is perplexed by its diverse biological activity, much of which remains inexplicable. The information reviewed here should point toward potential scope of future curcumin research in breast cancer.

Nanoformulated natural therapeutics for management of streptozotocin-induced diabetes: potential use of curcumin nanoformulation

Aim: The goal of this study was to improve curcumin (CUR) aqueous solubility and bioavailability via nanoformulation, and then study its activity and mechanism of action as an antidiabetic agent. Methods: CUR-loaded pluronic nanomicelles (CURnp) were prepared and characterized. Biochemical assessments were performed as well as histological, confocal and RTPCR studies on pancreatic target tissues. Results: CURnp with a diameter of 333 ± 6 nm and ζ potential of -26.1 mv were obtained. Antidiabetic action of CURnp was attributed to significant upregulation of Pdx-1 and NKx6.1 gene expression and achievement of optimum redox balance, which led to alleviation of streptozotocin-induced β-cell damage via a significant upregulation in insulin gene expression proved by RTPCR studies and by the presence of 40% insulin positive cells through confocal microscope studies on pancreatic tissue.

Preclinical studies for the combination of paclitaxel and curcumin in cancer therapy (Review)

Cancer is one of the most common causes of death and remains the first in China and the second in the US. The common treatments for cancer include surgery, radiation, chemotherapy, targeted therapy and immunotherapy, while chemotherapy remains one of the most important treatments. However, the efficacy of chemotherapy is limited due to drug induced-toxicities and resistance, particularly multiple drug resistance (MDR). Therefore, discovery and development of novel therapeutic drugs and/or combination therapy are urgently needed to reduce toxicity and improve efficacy. Paclitaxel has been widely used to treat various cancers including cervical, breast, ovarian, brain, bladder, prostate, liver and lung cancers. However, its therapeutic efficacy is limited and MDR is a major obstacle. Recently, numerous preclinical studies have shown that the combination of paclitaxel and curcumin may be an ideal strategy to reverse MDR and synergistically improve their therapeutic efficacy in cancer therapy. This review mainly focuses on the current development and progress of the combination of paclitaxel and curcumin in cancer therapy preclinically.

Development of Certain Protein Kinase Inhibitors with the Components from Traditional Chinese Medicine

Traditional Chinese medicines (TCMs) have been used in China for more than two thousand years, and some of them have been confirmed to be effective in cancer treatment. Protein kinases play critical roles in control of cell growth, proliferation, migration, survival, and angiogenesis and mediate their biological effects through their catalytic activity. In recent years, numerous protein kinase inhibitors have been developed and are being used clinically. Anticancer TCMs represent a large class of bioactive substances, and some of them display anticancer activity via inhibiting protein kinases to affect the phosphoinositide 3-kinase, serine/threonine-specific protein kinases, pechanistic target of rapamycin (PI3K/AKT/mTOR), P38, mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinases (ERK) pathways. In the present article, we comprehensively reviewed several components isolated from anticancer TCMs that exhibited significantly inhibitory activity toward a range of protein kinases. These components, which belong to diverse structural classes, are reviewed herein, based upon the kinases that they inhibit. The prospects and problems in development of the anticancer TCMs are also discussed.

Selecting optimum protein nano-carriers for natural polyphenols using chemoinformatics tools

BACKGROUND

The normal fate of any natural product with a therapeutic potential is to be formulated into an effective medicine. However, the conventional methods of selecting the suitable formulations or carriers based on the formulator experiences, trials and errors as well as materials availability do not usually yield the optimal results.

HYPOTHESIS

We hypothesize the possibility of the virtual optimum selection of a protein carrier for two polyphenolic compounds widely investigated for their chemopreventive effects; resveratrol and curcumin using a combination of some chemoinformatics tools.

METHODS

Two protein-based nanoparticles namely; albumin and gelatin nanoparticles were compared as carriers for the two selected phytochemicals; resveratrol and curcumin. Resveratrol-albumin, resveratrol-gelatin and curcumin-albumin results were gathered from the literature. While, a new combination (formulation), comprising curcumin as the cargo and gelatin nanoparticles as the carrier, was prepared and evaluated as a potential medicine for breast cancer. Combined chemoinformatics tools, namely; molecular dynamics and molecular docking were used to determine the optimum carrier for each of the two chemopreventive agents.

RESULTS

A new curcumin-gelatin nanoparticulate formulation was prepared and proven cytotoxic after an application period of 48h on MCF-7 breast cancer cell-lines scoring an IC₅₀ value of 64.8µg/ml. The utilized chemoinformatics tools comprising the molecular dynamics simulations of the protein nano-particulate drug-carriers followed by the molecular docking of phytochemical drugs on these carriers could capture the optimum protein carrier for each of the tested phytochemical and hence propose a successful formulation.

CONCLUSION

This study presents one in a series that proves the novel addressed concept of the utilization of computational tools rather than wet-lab experimentation in providing better selection of drug-carrier pairs aiming for better formulations and the subsequent successful therapeutic effects.

Unraveling the Anticancer Effect of Curcumin and Resveratrol

Resveratrol and curcumin are natural products with important therapeutic properties useful to treat several human diseases, including cancer. In the last years, the number of studies describing the effect of both polyphenols against cancer has increased; however, the mechanism of action in all of those cases is not completely comprehended. The unspecific effect and the ability to interfere in assays by both polyphenols make this challenge even more difficult. Herein, we analyzed the anticancer activity of resveratrol and curcumin reported in the literature in the last 11 years, in order to unravel the molecular mechanism of action of both compounds. Molecular targets and cellular pathways will be described. Furthermore, we also discussed the ability of these natural products act as chemopreventive and its use in association with other anticancer drugs.

A Subpopulation of the K562 Cells Are Killed by Curcumin Treatment after G2/M Arrest and Mitotic Catastrophe

Curcumin is extensively investigated as a good chemo-preventive agent in the development of many cancers and particularly in leukemia, including treatment of chronic myelogenous leukemia and it has been proposed as an adjuvant for leukemia therapies. Human chronic myeloid leukemia cells (K562), were treated with 20 μM of curcumin, and we found that a subpopulation of these cells were arrested and accumulate in the G2/M phase of the cell cycle. Characterization of this cell subpopulation showed that the arrested cells presented nuclear morphology changes resembling those described for mitotic catastrophe. Mitotic cells displayed abnormal chromatin organization, collapse of the mitotic spindle and abnormal chromosome segregation. Then, these cells died in an apoptosis dependent manner and showed diminution in the protein levels of BCL-2 and XIAP. Moreover, our results shown that a transient activation of the nuclear factor κB (NFκB) occurred early in these cells, but decreased after 6 h of the treatment, explaining in part the diminution of the anti-apoptotic proteins. Additionally, P73 was translocated to the cell nuclei, because the expression of the C/EBPα, a cognate repressor of the P73 gene, was decreased, suggesting that apoptosis is trigger by elevation of P73 protein levels acting in concert with the diminution of the two anti-apoptotic molecules. In summary, curcumin treatment might produce a P73-dependent apoptotic cell death in chronic myelogenous leukemia cells (K562), which was triggered by mitotic catastrophe, due to sustained BAX and survivin expression and impairment of the anti-apoptotic proteins BCL-2 and XIAP.

The Anti-Cancer Effect of Polyphenols against Breast Cancer and Cancer Stem Cells: Molecular Mechanisms

The high incidence of breast cancer in developed and developing countries, and its correlation to cancer-related deaths, has prompted concerned scientists to discover novel alternatives to deal with this challenge. In this review, we will provide a brief overview of polyphenol structures and classifications, as well as on the carcinogenic process. The biology of breast cancer cells will also be discussed. The molecular mechanisms involved in the anti-cancer activities of numerous polyphenols, against a wide range of breast cancer cells, in vitro and in vivo, will be explained in detail. The interplay between autophagy and apoptosis in the anti-cancer activity of polyphenols will also be highlighted. In addition, the potential of polyphenols to target cancer stem cells (CSCs) via various mechanisms will be explained. Recently, the use of natural products as chemotherapeutics and chemopreventive drugs to overcome the side effects and resistance that arise from using chemical-based agents has garnered the attention of the scientific community. Polyphenol research is considered a promising field in the treatment and prevention of breast cancer.

Targeting Nitric Oxide with Natural Derived Compounds as a Therapeutic Strategy in Vascular Diseases

Within the family of endogenous gasotransmitters, nitric oxide (NO) is the smallest gaseous intercellular messenger involved in the modulation of several processes, such as blood flow and platelet aggregation control, essential to maintain vascular homeostasis. NO is produced by nitric oxide synthases (NOS) and its effects are mediated by cGMP-dependent or cGMP-independent mechanisms. Growing evidence suggests a crosstalk between the NO signaling and the occurrence of oxidative stress in the onset and progression of vascular diseases, such as hypertension, heart failure, ischemia, and stroke. For these reasons, NO is considered as an emerging molecular target for developing therapeutic strategies for cardio- and cerebrovascular pathologies. Several natural derived compounds, such as polyphenols, are now proposed as modulators of NO-mediated pathways. The aim of this review is to highlight the experimental evidence on the involvement of nitric oxide in vascular homeostasis focusing on the therapeutic potential of targeting NO with some natural compounds in patients with vascular diseases.

Curcumin hampers the antitumor effect of vinblastine via the inhibition of microtubule dynamics and mitochondrial membrane potential in HeLa cervical cancer cells

BACKGROUND

Curcumin, a major component of curry powder, which is a natural polyphenol product extracted from rhizoma curcumae longae, interacts with a specific binding site on microtubules. Vinblastine is an antitumor drug that induces microtubule depolymerization.

PURPOSE

We investigated whether curcumin influences the antitumor effect of vinblastine in HeLa human cervical cancer cells.

STUDY DESIGN

Changes in microtubule filaments were visualized by immuno-staining. Cell death was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) or water-soluble tetrazolium(WST) assay. Apoptotic cell formation was assessed by flow cytometry after staining cells with propidium iodide(PI) and/or Annexin V or with 6-diamidino-2-phenylindole(DAPI). Reactive oxygen species(ROS) were also measured by flow cytometry using dichloro-dihydro-fluorescein diacetate(DCF-DA). JC-1 was used to determine mitochondrial membrane potential (MMP).

RESULTS

When cells were pretreated with curcumin, microtubule filaments were disordered. Vinblastine-induced microtubule depolymerization and cell death were reduced in HeLa human cervical cancer cells pretreated with curcumin compared to the control. The decrease in cell death was much greater in cells pretreated with curcumin compared to cotreatment or post-treatment. DNA condensation by vinblastine was also decreased in curcumin-pretreated cells. Curcumin reduced ROS production by vinblastine. However, no changes in vinblastine-mediated microtubule depolymerization were detected upon N-acetylcysteine(NAC) treatment. In contrast, vinblastine-induced MMP collapse was inhibited by pretreatment with curcumin or NAC. These findings suggest that vinblastine-induced tumor cell death might be inhibited by curcumin via ROS-independent microtubule dynamics and ROS-dependent MMP collapse. It also suggests that microtubule dynamics could be necessary for the optimal antitumor activity of vinblastine. Our results suggest that patients treated with vinblastine should not consume curcumin.

C1, a highly potent novel curcumin derivative, binds to tubulin, disrupts microtubule network and induces apoptosis

C1 is one of the most potent curcumin analogues identified till date which inhibits proliferation of various cancer cell lines. C1 binds to tubulin and depolymerized microtubules of MCF-7 cells. C1 altered the expression of apoptotic proteins and induces p53-dependent apoptosis.

We have synthesized a curcumin derivative, 4-{5-(4-hydroxy-3-methoxy-phenyl)-2-[3-(4-hydroxy-3-methoxy-phenyl)-acryloyl]-3-oxo-penta-1,4-dienyl}-piperidine-1-carboxylic acid tert-butyl ester (C1) that displays much stronger antiproliferative activity against various types of cancer cells including multidrug resistance cells than curcumin. C1 depolymerized both interphase and mitotic microtubules in MCF-7 cells and also inhibited the reassembly of microtubules in these cells. C1 inhibited the polymerization of purified tubulin, disrupted the lattice structure of microtubules and suppressed their GTPase activity in vitro. The compound bound to tubulin with a dissociation constant of 2.8±1 μM and perturbed the secondary structures of tubulin. Further, C1 treatment reduced the expression of Bcl2, increased the expression of Bax and down regulated the level of a key regulator of p53, murine double minute 2 (Mdm2) (S166), in MCF-7 cells. C1 appeared to induce p53 mediated apoptosis in MCF-7 cells. Interestingly, C1 showed more stability in aqueous buffer than curcumin. The results together showed that C1 perturbed microtubule network and inhibited cancer cells proliferation more efficiently than curcumin. The strong antiproliferative activity and improved stability of C1 indicated that the compound may have a potential as an anticancer agent.

Curcumin-treated cancer cells show mitotic disturbances leading to growth arrest and induction of senescence phenotype

Cellular senescence is recognized as a potent anticancer mechanism that inhibits carcinogenesis. Cancer cells can also undergo senescence upon chemo- or radiotherapy. Curcumin, a natural polyphenol derived from the rhizome of Curcuma longa, shows anticancer properties both in vitro and in vivo. Previously, we have shown that treatment with curcumin leads to senescence of human cancer cells. Now we identified the molecular mechanism underlying this phenomenon. We observed a time-dependent accumulation of mitotic cells upon curcumin treatment. The time-lapse analysis proved that those cells progressed through mitosis for a significantly longer period of time. A fraction of cells managed to divide or undergo mitotic slippage and then enter the next phase of the cell cycle. Cells arrested in mitosis had an improperly formed mitotic spindle and were positive for γH2AX, which shows that they acquired DNA damage during prolonged mitosis. Moreover, the DNA damage response pathway was activated upon curcumin treatment and the components of this pathway remained upregulated while cells were undergoing senescence. Inhibition of the DNA damage response decreased the number of senescent cells. Thus, our studies revealed that the induction of cell senescence upon curcumin treatment resulted from aberrant progression through the cell cycle. Moreover, the DNA damage acquired by cancer cells, due to mitotic disturbances, activates an important molecular mechanism that determines the potential anticancer activity of curcumin.

Molecular mechanisms underlying chemopreventive potential of curcumin: Current challenges and future perspectives

In recent years, natural compounds have received considerable attention in preventing and curing most dreadful diseases including cancer. The reason behind the use of natural compounds in chemoprevention is associated with fewer numbers of side effects than conventional chemotherapeutics. Curcumin (diferuloylmethane, PubMed CID: 969516), a naturally occurring polyphenol, is derived from turmeric, which is used as a common Indian spice. It governs numerous intracellular targets, including proteins involved in antioxidant response, immune response, apoptosis, cell cycle regulation and tumor progression. A huge mass of available studies strongly supports the use of Curcumin as a chemopreventive drug. However, the main challenge encountered is the low bioavailability of Curcumin. This extensive review covers various therapeutic interactions of Curcumin with its recognized cellular targets involved in cancer treatment, strategies to overcome the bioavailability issue and adverse effects associated with Curcumin consumption.

Colchicine induces autophagy and senescence in lung cancer cells at clinically admissible concentration: potential use of colchicine in combination with autophagy inhibitor in cancer therapy

Colchicine is a well-known and potent microtubule targeting agent, but the therapeutic value of colchicine against cancer is limited by its toxicity against normal cells. But, there is no report of its cytotoxic potential against lung cancer cell, at clinically permissible or lower concentrations, minimally toxic to non-cancerous cells. Hence, in the present study, we investigated the possible mechanism by which the efficacy of colchicine against lung cancer cells at less toxic dose could be enhanced. Colchicine at clinically admissible concentration of 2.5 nM had no cytotoxic effect and caused no G2/M arrest in A549 cells. However, at this concentration, colchicine strongly hindered the reformation of cold depolymerised interphase and spindle microtubule. Colchicine induced senescence and reactive oxygen species mediated autophagy in A549 cells at this concentration. Autophagy inhibitor 3-methyladenine (3-MA) sensitised the cytotoxicity of colchicine in A549 cells by switching senescence to apoptotic death, and this combination had reduced cytotoxicity to normal lung fibroblast cells (WI38). Together, these findings indicated the possible use of colchicine at clinically relevant dose along with autophagy inhibitor in cancer therapy.

Chemoprevention of Breast Cancer by Dietary Polyphenols

The review will discuss in detail the effects of polyphenols on breast cancer, including both the advantages and disadvantages of the applications of these natural compounds. First, we focus on the characterization of the main classes of polyphenols and then on in vitro and in vivo experiments carried out in breast cancer models. Since the therapeutic effects of the administration of a single type of polyphenol might be limited because of the reduced bioavailability of these drugs, investigations on combination of several polyphenols or polyphenols with conventional therapy will also be discussed. In addition, we present recent data focusing on clinical trials with polyphenols and new approaches with nanoparticles in breast cancer. Besides the clinical and translational findings this review systematically summarizes our current knowledge about the molecular mechanisms of anti-cancer effects of polyphenols, which are related to apoptosis, cell cycle regulation, plasma membrane receptors, signaling pathways and epigenetic mechanisms. At the same time the effects of polyphenols on primary tumor, metastasis and angiogenesis in breast cancer are discussed. The increasing enthusiasm regarding the combination of polyphenols and conventional therapy in breast cancer might lead to additional efforts to motivate further research in this field.

Comprehensive analysis of temporal alterations in cellular proteome of Bacillus subtilis under curcumin treatment

Curcumin is a natural dietary compound with antimicrobial activity against various gram positive and negative bacteria. This study aims to investigate the proteome level alterations in Bacillus subtilis due to curcumin treatment and identification of its molecular/cellular targets to understand the mechanism of action. We have performed a comprehensive proteomic analysis of B. subtilis AH75 strain at different time intervals of curcumin treatment (20, 60 and 120 min after the drug exposure, three replicates) to compare the protein expression profiles using two complementary quantitative proteomic techniques, 2D-DIGE and iTRAQ. To the best of our knowledge, this is the first comprehensive longitudinal investigation describing the effect of curcumin treatment on B. subtilis proteome. The proteomics analysis revealed several interesting targets such UDP-N-acetylglucosamine 1-carboxyvinyltransferase 1, putative septation protein SpoVG and ATP-dependent Clp protease proteolytic subunit. Further, in silico pathway analysis using DAVID and KOBAS has revealed modulation of pathways related to the fatty acid metabolism and cell wall synthesis, which are crucial for cell viability. Our findings revealed that curcumin treatment lead to inhibition of the cell wall and fatty acid synthesis in addition to differential expression of many crucial proteins involved in modulation of bacterial metabolism. Findings obtained from proteomics analysis were further validated using 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) assay for respiratory activity, resazurin assay for metabolic activity and membrane integrity assay by potassium and inorganic phosphate leakage measurement. The gene expression analysis of selected cell wall biosynthesis enzymes has strengthened the proteomics findings and indicated the major effect of curcumin on cell division.

A new 2α,5α,10β,14β-tetraacetoxy-4(20),11-taxadiene (SIA) derivative overcomes paclitaxel resistance by inhibiting MAPK signaling and increasing paclitaxel accumulation in breast cancer cells

Tumor resistance due to multiple mechanisms seriously hinders the efficacy of chemotherapy drugs such as paclitaxel. The most widely studied P-glycoprotein inhibitors still have limited ability to reverse resistance in the clinic. In this study, NPB304, a novel Sinenxan A (SIA) derivative, was found to significantly sensitize resistant breast cancer cells to paclitaxel in vitro and in vivo. Treatment with NPB304 increased paclitaxel-induced apoptosis in a p53-dependent manner through PARP cleavage. Importantly, NPB304 enhanced the antitumor effect of paclitaxel in resistant breast tumor xenografts in nude mice without significantly affecting weight loss. NPB304 regulated cell resistance through inhibition of MAPK pathway components, including p-ERK and p-p38. Moreover, NPB304 increased paclitaxel accumulation by affecting P-gp function. In addition to increasing Rhodamine 123 accumulation, NPB304 promoted bidirectional permeability but decreased the efflux ratio of paclitaxel in a Caco-2 monolayer model, thereby increasing the intracellular concentration of paclitaxel. Similarly, NPB304 increased the concentration of paclitaxel in the resistant tumor tissue. Hence, NPB304 is a novel compound that promotes the sensitization of resistant cells to paclitaxel through multiple mechanisms and has the potential for use in combination therapies to treat resistant breast cancer.

Curcumin-induced Aurora-A suppression not only causes mitotic defect and cell cycle arrest but also alters chemosensitivity to anticancer drugs

Overexpression of oncoprotein Aurora-A increases drug resistance and promotes lung metastasis of breast cancer cells. Curcumin is an active anticancer compound in turmeric and curry. Here we observed that Aurora-A protein and kinase activity were reduced in curcumin-treated human breast chemoresistant nonmetastatic MCF-7 and highly metastatic cancer MDA-MB-231 cells. Curcumin acts in a similar manner to Aurora-A small interfering RNA (siRNA), resulting in monopolar spindle formation, S and G2/M arrest, and cell division reduction. Ectopic Aurora-A extinguished the curcumin effects. The anticancer effects of curcumin were enhanced by Aurora-A siRNA and produced additivity and synergism effects in cell division and monopolar phenotype, respectively. Combination treatment with curcumin overrode the chemoresistance to four Food and Drug Administration (FDA)-approved anticancer drugs (ixabepilone, cisplatin, vinorelbine, or everolimus) in MDA-MB-231 cells, which was characterized by a decrease in cell viability and the occurrence of an additivity or synergy effect. Ectopic expression of Aurora-A attenuated curcumin-enhanced chemosensitivity to these four tested drugs. A similar benefit of curcumin was observed in MCF-7 cells treated with ixabepilone, the primary systemic therapy to patients with invasive breast cancer (stages IIA-IIIB) before surgery. Antagonism effect was observed when MCF-7 cells were treated with curcumin plus cisplatin, vinorelbine or everolimus. Curcumin-induced enhancement in chemosensitivity was paralleled by significant increases (additivity or synergy effect) in apoptosis and cell cycle arrest at S and G2/M phases, the consequences of Aurora-A inhibition. These results suggest that a combination of curcumin with FDA-approved anticancer drugs warrants further assessment with a view to developing a novel clinical treatment for breast cancer.

Synthesis and evaluation of 2-heteroaryl and 2,3-diheteroaryl-1,4-naphthoquinones that potently induce apoptosis in cancer cells

This article describes the preparation of 2-heteroaryl and 600 dpi in TIF format)??>2,3-diheteroaryl-1,4-naphthoquinones by an environmentally benign short synthetic route with the goal of finding 1,4-naphthoquinone derivatives that induce apoptosis in cancer cells.

Curcumin targets breast cancer stem-like cells with microtentacles that persist in mammospheres and promote reattachment

Cancer stem-like cells (CSC) and circulating tumor cells (CTC) have related properties associated with distant metastasis, but the mechanisms through which CSCs promote metastasis are unclear. In this study, we report that breast cancer cell lines with more stem-like properties display higher levels of microtentacles (McTN), a type of tubulin-based protrusion of the plasma cell membrane that forms on detached or suspended cells and aid in cell reattachment. We hypothesized that CSCs with large numbers of McTNs would more efficiently attach to distant tissues, promoting metastatic efficiency. The naturally occurring stem-like subpopulation of the human mammary epithelial (HMLE) cell line presents increased McTNs compared with its isogenic non-stem-like subpopulation. This increase was supported by elevated α-tubulin detyrosination and vimentin protein levels and organization. Increased McTNs in stem-like HMLEs promoted a faster initial reattachment of suspended cells that was inhibited by the tubulin-directed drug, colchicine, confirming a functional role for McTNs in stem cell reattachment. Moreover, live-cell confocal microscopy showed that McTNs persist in breast stem cell mammospheres as flexible, motile protrusions on the surface of the mammosphere. Although exposed to the environment, they also function as extensions between adjacent cells along cell-cell junctions. We found that treatment with the breast CSC-targeting compound curcumin rapidly extinguished McTN in breast CSC, preventing reattachment from suspension. Together, our results support a model in which breast CSCs with cytoskeletal alterations that promote McTNs can mediate attachment and metastasis but might be targeted by curcumin as an antimetastatic strategy.