Resveratrol mediated cell death in cigarette smoke transformed breast epithelial cells is through induction of p21Waf1/Cip1 and inhibition of long patch base excision repair pathway

Resveratrol nanoparticles induce apoptosis in oral cancer stem cells by disrupting the interaction between β-catenin and GLI-1 through p53-independent activation of p21

Cancer stem cells (CSCs) are mainly responsible for tumorigenesis, chemoresistance, and cancer recurrence. CSCs growth and progression are regulated by multiple signaling cascades including Wnt/β-catenin and Hh/GLI-1, which acts independently or via crosstalk. Targeting the crosstalk of signaling pathways would be an effective approach to control the CSC population. Both Wnt/β-catenin and Hh/GLI-1 signaling cascades are known to be regulated by p53/p21-dependent mechanism. However, it is interesting to delineate whether p21 can induce apoptosis in a p53-independent manner. Therefore, utilizing various subtypes of oral CSCs (SCC9-PEMT p53+/+p21+/+, SCC9-PEMT p53-/-p21+/+, SCC9-PEMT p53+/+p21-/- and SCC9-PEMT p53-/-p21-/-), we have examined the distinct roles of p53 and p21 in Resveratrol nanoparticle (Res-Nano)-mediated apoptosis. It is interesting to see that, besides the p53/p21-mediated mechanism, Res-Nano exposure also significantly induced apoptosis in oral CSCs through a p53-independent activation of p21. Additionally, Res-Nano-induced p21-activation deregulated the β-catenin-GLI-1 complex and consequently reduced the TCF/LEF and GLI-1 reporter activities. In agreement with in vitro data, similar experimental results were obtained in in vivo mice xenograft model.

Plant-based natural products in cancer therapeutics

Various cells in our body regularly divide to replace old cells and dead cells. For a living cell to be growing, cell division and differentiation is highly essential. Cancer is characterised by uncontrollable cell division and invasion of other tissues due to dysregulation in the cell cycle. An accumulation of genetic changes or mutations develops through different physical (UV and other radiations), chemical (chewing and smoking of tobacco, chemical pollutants/mutagens), biological (viruses) and hereditary factors that can lead to cancer. Now, cancer is considered as a major death-causing factor worldwide. Due to advancements in technology, treatment like chemotherapy, radiation therapy, bone marrow transplant, immunotherapy, hormone therapy and many more in the rows. Although, it also has some side effects like fatigue, hair fall, anaemia, nausea and vomiting, constipation. Modern improved drug therapies come with severe side effects. There is need for safer, more effective, low-cost treatment with lesser side-effects. Biologically active natural products derived from plants are the emerging strategy to deal with cancer proliferation. Moreover, they possess anti-carcinogenic, anti-proliferative and anti-mutagenic properties with reduced side effects. They also detoxify and remove reactive substances formed by carcinogenic agents. In this article, we discuss different plant-based products and their mechanism of action against cancer.

Premature senescence and cardiovascular disease following cancer treatments: mechanistic insights

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality, especially among the aging population. The "response-to-injury" model proposed by Dr. Russell Ross in 1999 emphasizes inflammation as a critical factor in atherosclerosis development, with atherosclerotic plaques forming due to endothelial cell (EC) injury, followed by myeloid cell adhesion and invasion into the blood vessel walls. Recent evidence indicates that cancer and its treatments can lead to long-term complications, including CVD. Cellular senescence, a hallmark of aging, is implicated in CVD pathogenesis, particularly in cancer survivors. However, the precise mechanisms linking premature senescence to CVD in cancer survivors remain poorly understood. This article aims to provide mechanistic insights into this association and propose future directions to better comprehend this complex interplay.

Substances of Natural Origin in Medicine: Plants vs. Cancer

Continuous monitoring of the population's health is the main method of learning about disease prevalence. National and international data draw attention to the persistently high rates of cancer incidence. This necessitates the intensification of efforts aimed at developing new, more effective chemotherapeutic and chemopreventive drugs. Plants represent an invaluable source of natural substances with versatile medicinal properties. Multidirectional activities exhibited by natural substances and their ability to modulate key signaling pathways, mainly related to cancer cell death, make these substances an important research direction. This review summarizes the information regarding plant-derived chemotherapeutic drugs, including their mechanisms of action, with a special focus on selected anti-cancer drugs (paclitaxel, irinotecan) approved in clinical practice. It also presents promising plant-based drug candidates currently being tested in clinical and preclinical trials (betulinic acid, resveratrol, and roburic acid).

Cucurbitacin-B Exerts Anticancer Effects through Instigation of Apoptosis and Cell Cycle Arrest within Human Prostate Cancer PC3 Cells via Downregulating JAK/STAT Signaling Cascade

Cucurbitacin-B (Cur-B) is an analogue triterpenoid belonging to the Cucurbitaceae family. Previous reports have explicitly outlined various biological activities of Cucurbitaceae family members, including the anticancer activity of Cur-B. In the present study, we tried to elucidate the anticancer efficacy of Cur-B against prostate cancer PC3 cells. PC3 cells were exposed to purified Cur-B at 5, 10, 15, 20 and 25 µM for 24. Cur-B exposure reduced cell viability of PC3 cells at 5 µM (p < 0.05), with further reduction with increased Cur-B concentration (15 µM, p < 0.01 and 25 µM, p < 0.001). Cur-B also succeeded in instigating nuclear fragmentation and condensation, followed by activation of caspase-8, -9 and -3 proportionally with increasing concentrations of Cur-B. Treatment with Cur-B also instigated ROS-mediated oxidative stress both qualitatively and quantitatively at 5 µM, p < 0.05; 15 µM, p < 0.01 and 25 µM, p < 0.001. Increased ROS after Cur-B treatment also led to dissipation of mitochondrial membrane potential, thereby resulting in considerable apoptosis (p < 0.001), which, again, was proportionally dependent on Cur-B concentration. Cur-B exposure to PC3 cells was concomitantly followed by reduced cyclin D1, cyclin-dependent kinase 4 (CDK4) expression and augmented mRNA expression of CDK inhibitor p21Cip1. Intriguingly, Cur-B exposure also led to considerable downregulation of the JAK/STAT signaling cascade, which may be the reason behind Cur-B-mediated apoptosis and cell cycle arrest within PC3 cells. Therefore, these observations explicitly establish that Cur-B could serve in the prevention of prostate cancer.

Resveratrol in breast cancer treatment: from cellular effects to molecular mechanisms of action

Breast cancer (BC) is one of the most common cancers in females and is responsible for the highest cancer-related deaths following lung cancer. The complex tumor microenvironment and the aggressive behavior, heterogenous nature, high proliferation rate, and ability to resist treatment are the most well-known features of BC. Accordingly, it is critical to find an effective therapeutic agent to overcome these deleterious features of BC. Resveratrol (RES) is a polyphenol and can be found in common foods, such as pistachios, peanuts, bilberries, blueberries, and grapes. It has been used as a therapeutic agent for various diseases, such as diabetes, cardiovascular diseases, inflammation, and cancer. The anticancer mechanisms of RES in regard to breast cancer include the inhibition of cell proliferation, and reduction of cell viability, invasion, and metastasis. In addition, the synergistic effects of RES in combination with other chemotherapeutic agents, such as docetaxel, paclitaxel, cisplatin, and/or doxorubicin may contribute to enhancing the anticancer properties of RES on BC cells. Although, it demonstrates promising therapeutic features, the low water solubility of RES limits its use, suggesting the use of delivery systems to improve its bioavailability. Several types of nano drug delivery systems have therefore been introduced as good candidates for RES delivery. Due to RES's promising potential as a chemopreventive and chemotherapeutic agent for BC, this review aims to explore the anticancer mechanisms of RES using the most up to date research and addresses the effects of using nanomaterials as delivery systems to improve the anticancer properties of RES.

Combination of talazoparib and olaparib enhanced the curcumin-mediated apoptosis in oral cancer cells by PARP-1 trapping

PURPOSE

Inhibition of Poly (ADP-ribose) Polymerases (PARP) results in the blocking of DNA repair cascades that eventually leads to apoptosis and cancer cell death. PARP inhibitors (PARPi) exhibit their actions either by inhibiting PARP-induced PARylation and/or by trapping PARP at the DNA damage site. But, the mechanism of PARPi-mediated induction of cellular toxicity via PARP-trapping is largely unknown.

METHODS

The cellular toxicity of PARPi [Talazoparib (BMN) and/or Olaparib (Ola)] was investigated in oral cancer cells and the underlying mechanism was studied by using in vitro, in silico, and in vivo preclinical model systems.

RESULTS

The experimental data suggested that induction of DNA damage is imperative for the optimal effectiveness of PARPi. Curcumin (Cur) exhibited maximum DNA damaging capacity in comparison to Resveratrol and 5-Flurouracil. Combination of BMN + Ola induced cell death in Cur pre-treated cells at much lower concentrations than their individual treatments. BMN + Ola treatment deregulated the BER cascade, potentiated PARP-trapping, caused cell cycle arrest and apoptosis in Cur pre-treated cells in a much more effective manner than their individual treatments. In silico data indicated the involvement of different amino acid residues which might play important roles in enhancing the BMN + Ola-mediated PARP-trapping. Moreover, in vivo mice xenograft data also suggested the BMN + Ola-mediated enhancement of apoptotic potentiality of Cur.

CONCLUSION

Thus, induction of DNA damage was found to be essential for optimal functioning of PARPi and BMN + Ola combination treatment enhanced the apoptotic potentiality of Cur in cancer cells by enhancing the PARP-trapping activity via modulation of BER cascade.

Revisiting the Function of p21CDKN1A in DNA Repair: The Influence of Protein Interactions and Stability

The p21CDKN1A protein is an important player in the maintenance of genome stability through its function as a cyclin-dependent kinase inhibitor, leading to cell-cycle arrest after genotoxic damage. In the DNA damage response, p21 interacts with specific proteins to integrate cell-cycle arrest with processes such as transcription, apoptosis, DNA repair, and cell motility. By associating with Proliferating Cell Nuclear Antigen (PCNA), the master of DNA replication, p21 is able to inhibit DNA synthesis. However, to avoid conflicts with this process, p21 protein levels are finely regulated by pathways of proteasomal degradation during the S phase, and in all the phases of the cell cycle, after DNA damage. Several lines of evidence have indicated that p21 is required for the efficient repair of different types of genotoxic lesions and, more recently, that p21 regulates DNA replication fork speed. Therefore, whether p21 is an inhibitor, or rather a regulator, of DNA replication and repair needs to be re-evaluated in light of these findings. In this review, we will discuss the lines of evidence describing how p21 is involved in DNA repair and will focus on the influence of protein interactions and p21 stability on the efficiency of DNA repair mechanisms.

Induction of apoptosis in human hormone-refractory prostate cancer cell lines by using resveratrol in combination with AT-101

The aim of this study was to determine the appropriate doses of AT-101 and resveratrol combination in the in vitro hormone-refractory prostate cancer (PC) cell lines, in order to evaluate the cytotoxic and genotoxic effects of this combination on the proliferation of cancer cells, namely PC-3, DU-145 and LNCAP. Cytotoxicity in PC cell lines was analysed by using the XTT Cell Proliferation Assay. DNA damage was performed with the cell death assay. Apoptotic protein levels were performed by Roche Human Apoptosis Array. IC50 values were determined by XTT analysis. The strongest combined doses (100 µM resveratrol + 5µM AT-101) were found to have the strongest synergistic apoptotic and cytotoxic effects on DU-145 cells at 72 hr. While the combined use of resveratrol and AT-101 increased the expression of markers in apoptotic cell pathways on cells, a decrease in the expression of anti-apoptotic markers was detected (p ˂ 0.05). Combined applications of these compounds showed an important synergism in the hormone-refractory PC cell lines, and it was determined that after the post-translational modification, they were significantly effective on the apoptotic pathway. These results have revealed that the combination of resveratrol and AT-101 holds great expectation as a new chemotherapeutic application in the treatment of human prostate cancer.

Glycyrrhizin Mediates Downregulation of Notch Pathway Resulting in Initiation of Apoptosis and Disruption in the Cell Cycle Progression in Cervical Cancer Cells

Growing emphasis on exploring the antiproliferative potential of natural compounds has gathered momentum for the formulation of anticancer drugs. In the present study, the anticancer and apoptotic potential of glycyrrhizin (GLY) was studied on HPV^- C33A cervical cancer (CCa) cells. Our results indicated that GLY exerted antiproliferative effects in the C33A cells by inducing significant cytotoxicity. Treatment with GLY substantially increases the apoptosis in a dose-dependent manner via disrupting the mitochondrial membrane potential. GLY induced apoptosis in C33A cells via activation of capsase-9 (intrinsic pathway) and caspase-8 (extrinsic pathway) along with the modulation of pro- and antiapoptotic protein expression. Moreover, GLY also exerted cell cycle arrest in C33A cells at G₀/G₁ phase which was associated with the decreased expression of cyclin D1 and cyclin-dependent kinase 4 (CDK4) along with the increased expression of CDK inhibitor p21^Cip1. Furthermore, GLY treated CCa cells exhibited significant downregulation of Notch signaling pathway which may be associated with increased apoptosis as well as cell cycle arrest in C33A CCa cells. Thus, GLY could be an appendage in the prevention and management of CCa.

Development of Animal Models for Lens and Corneal Diseases Using N-Methyl-N-Nitrosourea

Purpose

N-methyl-N-nitrosourea (MNU) is an alkylating toxicant with potent mutagenic ability. This study was designed to induce apoptosis in lens epithelial cells (LECs) and corneal endothelial cells (CECs) via MNU administration. We sought to build ocular disease models of cataract and corneal endothelial decompensation.

Methods

MNU was delivered into the intraperitoneal cavities of neonatal rats and the anterior chambers of adult rabbits. The MNU-treated animals were then subjected to a series of functional and morphological analyses at various time points.

Results

MNU treatment induced pervasive apoptosis of LECs and CECs. These effects were dose and time dependent. Mature cataracts were found in neonatal rats 3 weeks after MNU treatment. Histological analysis revealed that MNU toxicity induced swelling, vacuolation, and liquefaction in lens fibers of MNU-treated rats. Pentacam examination showed that the average density of rat lens increased significantly after MNU administration. Terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) analysis showed pervasive apoptotic staining in the lenses of MNU-treated rats. In rabbit eyes, intracameral treatment with MNU induced corneal edema and significantly increased central corneal thickness, which peaked at P14. Morphological and immunohistochemical analysis showed that CECs were effectively ablated in the MNU-treated rabbits. The expression of 8-OHdG increased significantly in the cornea of MNU-treated rabbits, compared with vehicle-treated controls.

Conclusions

MNU is sufficient to induce ocular cell apoptosis in animal models. These models of MNU-induced cataract and corneal endothelial decompensation represent valuable tools for efforts to develop relevant therapies.

Still Living Better through Chemistry: An Update on Caloric Restriction and Caloric Restriction Mimetics as Tools to Promote Health and Lifespan

Caloric restriction (CR), the reduction of caloric intake without inducing malnutrition, is the most reproducible method of extending health and lifespan across numerous organisms, including humans. However, with nearly one-third of the world’s population overweight, it is obvious that caloric restriction approaches are difficult for individuals to achieve. Therefore, identifying compounds that mimic CR is desirable to promote longer, healthier lifespans without the rigors of restricting diet. Many compounds, such as rapamycin (and its derivatives), metformin, or other naturally occurring products in our diets (nutraceuticals), induce CR-like states in laboratory models. An alternative to CR is the removal of specific elements (such as individual amino acids) from the diet. Despite our increasing knowledge of the multitude of CR approaches and CR mimetics, the extent to which these strategies overlap mechanistically remains unclear. Here we provide an update of CR and CR mimetic research, summarizing mechanisms by which these strategies influence genome function required to treat age-related pathologies and identify the molecular fountain of youth.

Natural Compounds That Target DNA Repair Pathways and Their Therapeutic Potential to Counteract Cancer Cells

Resistance to current cancer treatments is an important problem that arises through various mechanisms, but one that stands out involves an overexpression of several factors associated with DNA repair. To counteract this type of resistance, different drugs have been developed to affect one or more DNA repair pathways, therefore, to test different compounds of natural origin that have been shown to induce cell death in cancer cells is paramount. Since natural compounds target components of the DNA repair pathways, they have been shown to promote cancer cells to be resensitized to current treatments. For this and other reasons, natural compounds have aroused great curiosity and several research projects are being developed around the world to establish combined treatments between them and radio or chemotherapy. In this work, we summarize the effects of different natural compounds on the DNA repair mechanisms of cancer cells and emphasize their possible application to re-sensitize these cells.

Anti-tumor properties of methoxylated analogues of resveratrol in malignant MCF-7 but not in non-tumorigenic MCF-10A mammary epithelial cell lines

Resveratrol is a plant-derived polyphenol that is known for its anti-inflammatory and anti-tumorigenic properties in in vitro and in vivo models. Recent studies show that some resveratrol analogues might be more potent anti-tumor agents, which may partly be attributed to their ability to activate the aryl hydrocarbon receptor (AHR). Here, the anti-tumorigenic properties of resveratrol and structural analogues oxyresveratrol, pinostilbene, pterostilbene and tetramethoxystilbene (TMS) were studied in vitro, using in the malignant human MCF-7 breast cancer cell line and non-tumorigenic breast epithelial cell line MCF-10A. Cell viability and migration assays showed that methoxylated analogues of resveratrol are more potent anti-tumorigenic compounds than resveratrol and its hydroxylated analogue oxyresveratrol, with 2,3',4,5'-tetramethoxy-trans-stilbene (TMS) being the most potent compound. TMS decreased MCF-7 tumor cell viability with 50% at 3.6 μM and inhibited migration with 37.5 ± 14.8% at 3 μM. In addition, TMS activated the AHR more potently (EC50 in a reporter gene assay 2.0 μM) and induced AHR-mediated induction of cytochrome P450 1A1 (CYP1A1) activity (EC50 value of 0.7 μM) more than resveratrol and the other analogues tested. Cell cycle analysis showed that TMS induced a shift in cell cycle status from the G1 to the G2/M phase causing a cell cycle arrest in the MCF-7 cells, while no effect of TMS was observed in the non-tumorigenic MCF-10A mammary epithelial cell line. Gene expression analysis showed that 3 μM TMS increased gene expression of CYP1A1 (289-fold), CYP1B1 (5-fold) and Nqo1 (2-fold), and decreased gene expression of IL-8 (3-fold) in MCF-7 cells. In MCF-10A cells, 10 μM TMS also increased gene expression of CYP1A1 (5-fold) and CYP1B1 (2-fold), but decreased gene expression of Nqo1 (1.4-fold) in contrast to MCF-7 cells. TMS displays more potent anti-tumorigenic properties and activates the AHR more effectively than resveratrol. In addition, this is the first study to show that TMS, but not resveratrol, selectively inhibits the cell cycle of breast tumor cells and not the non-tumorigenic cells. Our study provides more insight in the anti-tumor properties of the methoxylated analogues of resveratrol in breast cells in vitro.

Quinacrine induces apoptosis in cancer cells by forming a functional bridge between TRAIL-DR5 complex and modulating the mitochondrial intrinsic cascade

Death Receptor 5 (DR5) is known to be an important anti-cancer drug target. TRAIL is a natural ligand of DR5, but its drug action is limited because of several factors. A few agonistic ligands were identified as TRAIL-DR5 axis modulators, which enhance the cellular apoptosis. Literature suggest that quinacrine (QC) acts as a DR5 agonistic ligand. However, the detailed mechanism explaining how QC interacts with TRAIL-DR5 axis has not been established. Also focused in vitro and in vivo experimental analysis to validate the hypothesis is not yet performed. In this work, extensive studies have been carried out using in silico analysis (molecular dynamics), in vitro analysis (cell based assays) and in vivo analysis (based on mice xenograft model), to delineate the mechanism of QC action in modulating the TRAIL-DR5 signaling. The MD simulations helped in identifying the important residues contributing to the formation of a QC-TRAIL-DR5 complex, which provide extra stability to it, consequently leading to the enhanced cellular apoptosis. QC caused a dose dependent increase of DR5 expression in cancer cells but not in normal breast epithelial cells, MCF-10A. QC showed a synergistic effect with TRAIL in causing cancer cell apoptosis. In DR5-KD MCF-10A-Tr (DR5 knocked down) cells, TRAIL+ QC failed to significantly increase the apoptosis but over expression of full length DR5 in DR5-silence cells induced apoptosis, further supporting DR5 as a drug target for QC. An increase in the release of reactive species (ROS and RNS) and activation of enzymes (FADD, CASPASES 3, 8, 9 and cytochrome-C) indicated the involvement of mitochondrial intrinsic pathway in TRAIL+QC mediated apoptosis. In vivo study pointed out that TRAIL+QC co-administration increases the expression of DR5 and reduce the tumor size in xenograft mice. This combined in silico, in vitro and in vivo analysis revealed that QC enhances the cellular apoptosis via the modulation of TRAIL-DR5 complexation and the mitochondrial intrinsic pathway.

The Role of Resveratrol in Cancer Therapy

Natural product compounds have recently attracted significant attention from the scientific community for their potent effects against inflammation-driven diseases, including cancer. A significant amount of research, including preclinical, clinical, and epidemiological studies, has indicated that dietary consumption of polyphenols, found at high levels in cereals, pulses, vegetables, and fruits, may prevent the evolution of an array of diseases, including cancer. Cancer development is a carefully orchestrated progression where normal cells acquires mutations in their genetic makeup, which cause the cells to continuously grow, colonize, and metastasize to other organs such as the liver, lungs, colon, and brain. Compounds that modulate these oncogenic processes can be considered as potential anti-cancer agents that may ultimately make it to clinical application. Resveratrol, a natural stilbene and a non-flavonoid polyphenol, is a phytoestrogen that possesses anti-oxidant, anti-inflammatory, cardioprotective, and anti-cancer properties. It has been reported that resveratrol can reverse multidrug resistance in cancer cells, and, when used in combination with clinically used drugs, it can sensitize cancer cells to standard chemotherapeutic agents. Several novel analogs of resveratrol have been developed with improved anti-cancer activity, bioavailability, and pharmacokinetic profile. The current focus of this review is resveratrol’s in vivo and in vitro effects in a variety of cancers, and intracellular molecular targets modulated by this polyphenol. This is also accompanied by a comprehensive update of the various clinical trials that have demonstrated it to be a promising therapeutic and chemopreventive agent.

Benzofuran-2-acetic ester derivatives induce apoptosis in breast cancer cells by upregulating p21Cip/WAF1 gene expression in p53-independent manner

Breast cancer is the most common malignancy and the leading cause of cancer-related death in women worldwide. High toxicity of used chemotherapeutics and resistance of cancer cells to treatments are a driving force for searching the new drug candidates for breast cancer therapy. In this study, we tested the antiproliferative effects of a series of benzofuran-2-acetic methyl ester derivatives, synthesized by a palladium-catalyzed carbonylative heterocyclization approach, on breast cancer cells. We observed that benzofuran compounds bearing a phenyl or tert-butyl substituent α to the methoxycarbonyl group significantly inhibited anchorage-dependent and -independent cell growth, and induced G0/G1 cell cycle arrest in human estrogen receptor alpha positive (MCF-7 and T47D) and in triple negative MDA-MB-231 breast cancer cells, without affecting growth of MCF-10A normal breast epithelial cells. Mechanistically, benzofuran derivatives enhanced the cyclin-dependent kinase inhibitor p21^Cip/WAF1 expression at both mRNA and protein levels and this occurs transcriptionally in an Sp1-dependent manner. Moreover, benzofuran derivatives induced apoptosis, increased poly (ADP-ribose) polymerase cleavage and Bax/Bcl-2 ratio along with a marked DNA fragmentation along with a marked DNA fragmentation and a strong increase in TUNEL-positive breast cancer cells. Overall, we provide evidence that the newly tested benzofuran derivatives showed antiproliferative and pro-apoptotic activities against breast cancer cells regardless estrogen receptor status, suggesting their possible clinical development as anticancer agents.

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.

SURVIVIN as a marker for quiescent-breast cancer stem cells-An intermediate, adherent, pre-requisite phase of breast cancer metastasis

Cancer stem cells drive the metastatic cascade by undergoing epithelial to mesenchymal transition (EMT) and again mesenchymal to epithelial transition (MET). Using multiple breast cancer cell lines including cigarette smoke induced breast cancer cells and tumor derived primary cells from patient sample; we developed a breast cancer metastasis model and reported the existence of an adherent, distinct pre-metastatic phase, quiescent-breast cancer stem cells (Q-BCSCs) prior to attaining an EMT. SURVIVIN was found to be expressed in Q-BCSCs. Time dependant biphasic expression of SURVIVIN in Q-BCSCs reveals that Q-BCSCs is a pre-metastatic phase distinct from both epithelial and mesenchymal counterparts. SURVIVIN favours metastasis and up-regulates WNT/β-CATENIN pathway in a PI3 K/AKT-dependant manner for self-renewal. Knockdown of SURVIVIN in Q-BCSCs lost the metastatic property of cells by inhibiting invasion, EMT-MET, PI3 K/AKT/WNT cascade, and induced apoptosis. Thus, our data suggest the existence of a novel pre-metastatic phase (Q-BCSCs) before EMT and SURVIVIN acts as a marker for Quiescent-BCSCs.

Nanoquinacrine induced apoptosis in cervical cancer stem cells through the inhibition of hedgehog-GLI1 cascade: Role of GLI-1

To improve the pharmacokinetics and to study the anti-cervical cancer and anti-stem cells (CSCs) mechanism of Quinacrine (QC), a spherical nano particle of QC (i.e. NQC) was prepared and characterized. QC and NQC showed higher cytotoxicity in multiple cancer cells than the normal epithelial cells. NQC exhibited more toxicity in cervical cancer cells and its CSCs than QC. A dose-dependent decreased expression of Hedgehog-GLI (HH-GLI) components were noted in NQC treated HeLa cells and its CSCs. NQC increased the expressions of negatively regulated HH-GLI components (GSK3β, PTEN) and caused apoptosis in CSCs. Reduction of GLI1 at mRNA and promoter level were noted after NQC exposure. The expressions of HH-GLI components, GLI1 promoter activity and apoptosis were unaltered in NQC treated GLI1-knockdown cells. In silico, cell based and in vitro reconstitution assay revealed that NQC inhibit HH-GLI cascade by binding to the consensus sequence (5'GACCACCCA3') of GLI1 in GLI-DNA complex through destabilizing DNA-GLI1 complex. NQC reduced the tumors size and proliferation marker Ki-67 in an in vivo xenograft mice model. Thus, NQC induced apoptosis in cancers through inhibition of HH-GLI cascade by GLI1. Detail interaction of QC-DNA-GLI complex can pave path for anticancer drug design.

Resveratrol for breast cancer prevention and therapy: Preclinical evidence and molecular mechanisms

Globally, breast cancer is the most frequently diagnosed cancer among women. The major unresolved problems with metastatic breast cancer is recurrence after receiving objective response to chemotherapy, drug-induced side effects of first line chemotherapy and delayed response to second line of treatment. Unfortunately, very few options are available as third line treatment. It is clear that under such circumstances there is an urgent need for new and effective drugs. Phytochemicals are among the most promising chemopreventive treatment options for the management of cancer. Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a non-flavonoid polyphenol present in several dietary sources, including grapes, berries, soy beans, pomegranate and peanuts, has been shown to possess a wide range of health benefits through its effect on a plethora of molecular targets.The present review encompasses the role of resveratrol and its natural/synthetic analogue in the light of their efficacy against tumor cell proliferation, metastasis, epigenetic alterations and for induction of apoptosis as well as sensitization toward chemotherapeutic drugs in various in vitro and in vivo models of breast cancer. The roles of resveratrol as a phytoestrogen, an aromatase inhibitor and in stem cell therapy as well as adjuvent treatment are also discussed. This review explores the full potential of resveratrol in breast cancer prevention and treatment with current limitations, challenges and future directions of research.

Cancer prevention and therapy through the modulation of the tumor microenvironment

Cancer arises in the context of an in vivo tumor microenvironment. This microenvironment is both a cause and consequence of tumorigenesis. Tumor and host cells co-evolve dynamically through indirect and direct cellular interactions, eliciting multiscale effects on many biological programs, including cellular proliferation, growth, and metabolism, as well as angiogenesis and hypoxia and innate and adaptive immunity. Here we highlight specific biological processes that could be exploited as targets for the prevention and therapy of cancer. Specifically, we describe how inhibition of targets such as cholesterol synthesis and metabolites, reactive oxygen species and hypoxia, macrophage activation and conversion, indoleamine 2,3-dioxygenase regulation of dendritic cells, vascular endothelial growth factor regulation of angiogenesis, fibrosis inhibition, endoglin, and Janus kinase signaling emerge as examples of important potential nexuses in the regulation of tumorigenesis and the tumor microenvironment that can be targeted. We have also identified therapeutic agents as approaches, in particular natural products such as berberine, resveratrol, onionin A, epigallocatechin gallate, genistein, curcumin, naringenin, desoxyrhapontigenin, piperine, and zerumbone, that may warrant further investigation to target the tumor microenvironment for the treatment and/or prevention of cancer.

Enhancement of Cytotoxicity and Inhibition of Angiogenesis in Oral Cancer Stem Cells by a Hybrid Nanoparticle of Bioactive Quinacrine and Silver: Implication of Base Excision Repair Cascade

A poly(lactic-co-glycolic acid) (PLGA)-based uniform (50-100 nm) hybrid nanoparticle (QAgNP) with positive zeta potential (0.52 ± 0.09 mV) was prepared by single emulsion solvent evaporation method with bioactive small molecule quinacrine (QC) in organic phase and silver (Ag) in aqueous phase. Physiochemical properties established it as a true hybrid nanoparticle and not a mixture of QC and Ag. Antitumor activity of QAgNP was evaluated by using various cancer cell lines including H-357 oral cancer cells and OSCC-cancer stem cell in an in vitro model system. QAgNP caused more cytotoxicity in cancer cells than normal epithelial cells by increasing BAX/BCL-XL, cleaved product PARP-1, and arresting the cells at S phase along with DNA damage. In addition, QAgNPs offered greater ability to kill the OSCC-CSCs compared to NQC and AgNPs. QAgNP offered anticancer action in OSCC-CSCs by inhibiting the base excision repair (BER) within the cells. Interestingly, alteration of BER components (Fen-1 and DNA polymerases (β, δ, and ε) and unalteration of NHEJ (DNA-PKC) or HR (Rad-51) components was noted in QAgNP treated OSCC-CSC cells. Furthermore, QAgNP significantly reduced angiogenesis in comparison to physical mixture of NQC and AgNP in fertilized eggs. Thus, these hybrid nanoparticles caused apoptosis in OSCC-CSCs by inhibiting the angiogenesis and BER in cells.

Resveratrol and curcumin synergistically induces apoptosis in cigarette smoke condensate transformed breast epithelial cells through a p21(Waf1/Cip1) mediated inhibition of Hh-Gli signaling

Combination therapy using two or more small molecule inhibitors of aberrant signaling cascade in aggressive breast cancers is a promising therapeutic strategy over traditional monotherapeutic approaches. Here, we have studied the synergistic mechanism of resveratrol and curcumin induced apoptosis using in vitro (cigarette smoke condensate mediated transformed breast epithelial cell, MCF-10A-Tr) and in vivo (tumor xenograft mice) model system. Resveratrol exposure increased the intracellular uptake of curcumin in a dose dependent manner and caused apoptosis in MCF-10A-Tr cells. Approximately, ten fold lower IC50 value was noted in cells treated with the combination of resveratrol (3μM) and curcumin (3μM) in comparison to 30μM of resveratrol or curcumin alone. Resveratrol+curcumin combination caused apoptosis by increasing Bax/Bcl-xL ratio, Cytochrome C release, cleaved product of PARP and caspase 3 in cells. Interestingly, this combination unaltered the protein expressions of WNT-TCF and Notch signaling components, β-catenin and cleaved notch-1 val1744, respectively. Furthermore, the combination also significantly decreased the intermediates of Hedgehog-Gli cascade including SMO, SHH, Gli-1, c-MYC, Cyclin-D1, etc. and increased the level of p21(Waf/Cip1) in vitro and in vivo. A significant reduction of Gli- promoter activity was noted in combinational drug treated cells in comparison to individual drug treatment. Un-alteration of the expressions of the above proteins and Gli1 promoter activity in p21(Waf/Cip1) knockout cells suggests this combination caused apoptosis through p21(Waf/Cip1). Thus, our findings revealed resveratrol and curcumin synergistically caused apoptosis in cigarette smoke induced breast cancer cells through p2(Waf/Cip1) mediated inhibition of Hedgehog-Gli cascade.

Evaluation of four human cell lines with distinct biotransformation properties for genotoxic screening

In a previous study, we validated an in vitro genotoxicity assay based on γH2AX quantification using the In-Cell Western (ICW) method in HepG2 cells. The assay demonstrated high sensitivity and specificity but failed to detect genotoxicity for few compounds that require specific metabolic bioactivation not sufficiently covered by HepG2 cells. The aim of the present study was to assess γH2AX ICW sensitivity using a broader range of genotoxic molecules with HepG2 cells and three additional human cell lines with distinct biotransformation properties: two cell lines expressing some phase I and II bioactivation capabilities (LS-174T and Hep3B), and one with poor general bioactivation properties (ACHN). We evaluated the four cell lines by testing 24 compounds recommended by European Centre for the Validation of Alternative Methods and a set of 24 additional chemicals with different mode of genotoxic action (MOA) (aneugenicity, DNA adducts formation, induction of oxidative stress), including some known to require specific cytochrome P450 metabolic bioactivation. Results for the 48 compounds tested showed that the γH2AX ICW assay was more sensitive with LS-174T and HepG2 cells than with Hep3B or ACHN cell lines. Among the 38 compounds tested with positive or equivocal carcinogenicity data, 36 (95%) showed a positive genotoxic response with the γH2AX ICW assay compared to only 27 (71%) using the Ames assay. We confirm that the γH2AX ICW assay on HepG2 cells, without an exogenous metabolic activation system, may be a suitable test to predict the in vivo genotoxicity of chemicals with different genotoxic MOA. Moreover, the use of the ACHN cell line in combination with LS-174T and HepG2 cells may permit in many cases to discriminate direct from bioactivated genotoxins. Overall, our results confirm the high sensitivity of the γH2AX ICW assay which, in turn, should reduce the number of animals used for genotoxicity assessment.

3,4',5-trans-Trimethoxystilbene; a natural analogue of resveratrol with enhanced anticancer potency

Resveratrol is a phytoalexin produced by many plant species as a defence mechanism. Over the last decade, this polyphenol has been reported to be active against multiple targets associated with chronic disorders. However, its poor pharmacokinetic profile, as well as multiple discrepancies related to its in vitro and in vivo profile, has resulted not only on the study of suitable delivery systems, but the use of resveratrol derivatives. In this regard, the 3,4',5-trans-trimethoxystilbene (TMS), a natural analogue of resveratrol, has emerged as a strong candidate. TMS has an enhanced anticancer profile compared to resveratrol, exhibiting higher potency than resveratrol, as shown by multiple reports describing an improved cancer cell proliferation inhibition, induction of cell cycle arrest, decreased metastasis, reduced angiogenesis, and increased apoptosis. In this review, we provide a concise summary of results reported in the literature, related to the similarities and differences between resveratrol and TMS, and we submit to the scientific community that TMS is a promising and (still) understudied natural agent candidate, with potential applications in cancer research. Nevertheless, based on the available evidence, we also submit to the scientific community that TMS may also find a niche in any other research area in which resveratrol has been used.

The pharmacology of resveratrol in animals and humans

In addition to thousands of research papers related to resveratrol (RSV), approximately 300 review articles have been published. Earlier research tended to focus on pharmacological activities of RSV related to cardiovascular systems, inflammation, and carcinogenesis/cancer development. More recently, the horizon has been broadened by exploring the potential effect of RSV on the aging process, diabetes, neurological dysfunction, etc. Herein, we primarily focus on the in vivo pharmacological effects of RSV reported over the past 5 years (2009-2014). In addition, recent clinical intervention studies performed with resveratrol are summarized. Some discrepancies exist between in vivo studies with animals and clinical studies, or between clinical studies, which are likely due to disparate doses of RSV, experimental settings, and subject variation. Nevertheless, many positive indications have been reported with mammals, so it is reasonable to advocate for the conduct of more definitive clinical studies. Since the safety profile is pristine, an added advantage is the use of RSV as a dietary supplement. This article is part of a Special Issue entitled: Resveratrol: Challenges in translating pre-clinical findings to improved patient outcomes.

Human AP endonuclease 1: a potential marker for the prediction of environmental carcinogenesis risk

Human apurinic/apyrimidinic endonuclease 1 (APE1) functions mainly in DNA repair as an enzyme removing AP sites and in redox signaling as a coactivator of various transcription factors. Based on these multifunctions of APE1 within cells, numerous studies have reported that the alteration of APE1 could be a crucial factor in development of human diseases such as cancer and neurodegeneration. In fact, the study on the combination of an individual's genetic make-up with environmental factors (gene-environment interaction) is of great importance to understand the development of diseases, especially lethal diseases including cancer. Recent reports have suggested that the human carcinogenic risk following exposure to environmental toxicants is affected by APE1 alterations in terms of gene-environment interactions. In this review, we initially outline the critical APE1 functions in the various intracellular mechanisms including DNA repair and redox regulation and its roles in human diseases. Several findings demonstrate that the change in expression and activity as well as genetic variability of APE1 caused by environmental chemical (e.g., heavy metals and cigarette smoke) and physical carcinogens (ultraviolet and ionizing radiation) is likely associated with various cancers. These enable us to ultimately suggest APE1 as a vital marker for the prediction of environmental carcinogenesis risk.