Two novel aspirin analogues show selective cytotoxicity in primary chronic lymphocytic leukaemia cells that is associated with dual inhibition of Rel A and COX-2

Expression and Activity of the NF-κB Subunits in Chronic Lymphocytic Leukaemia: A Role for RelB and Non-Canonical Signalling

BACKGROUND

Canonical NF-κB signalling by p65 (RelA) confers chemo-resistance and poor survival in chronic lymphocytic leukaemia (CLL). The role of non-canonical NF-κB signalling (leading to RelB and p52 subunit activation) in CLL is less understood, but given its importance in other B-cell tumour types, we theorised that RelB and p52 may also contribute to the pathology of CLL.

METHODS

DNA binding activity of all five NF-kB subunits, p65, p50, RelB, p52, and c-Rel, was quantified using ELISA and correlated to ex vivo chemoresistance, CD40L-stimulated signalling (to mimic the lymph node microenvironment), and clinical data.

RESULTS

Importantly, we show for the first time that high basal levels of RelB DNA binding correlate with nuclear RelB protein expression and are associated with del(11q), ATM dysfunction, unmutated IGHV genes, and shorter survival. High levels of nuclear p65 are prevalent in del(17p) cases (including treatment-naïve patients) and also correlate with the outcome. CD40L-stimulation resulted in rapid RelB activation, phosphorylation and processing of p100, and subsequent CLL cell proliferation.

CONCLUSIONS

These data highlight a role for RelB in driving CLL cell tumour growth in a subset of patients and therefore strategies designed to inhibit non-canonical NF-κB signalling represent a novel approach that will have therapeutic benefit in CLL.

Resveratrol Suppresses Cross-Talk between Colorectal Cancer Cells and Stromal Cells in Multicellular Tumor Microenvironment: A Bridge between In Vitro and In Vivo Tumor Microenvironment Study

The interaction between tumor cells and the tumor microenvironment (TME) is an important process for the development of tumor malignancy. Modulation of paracrine cross-talk could be a promising strategy for tumor control within the TME. The exact mechanisms of multi-targeted compound resveratrol are not yet fully understood. Whether resveratrol can modulate paracrine signal transduction-induced malignancy in the multicellular-TME of colorectal cancer cells (CRC) was investigated. An in vitro model with 3D-alginate HCT116 cells in multicellular-TME cultures (fibroblast cells, T-lymphocytes) was used to elucidate the role of TNF-β, Sirt1-ASO and/or resveratrol in the proliferation, invasion and cancer stem cells (CSC) of CRC cells. We found that multicellular-TME, similar to TNF-β-TME, promoted proliferation, colony formation, invasion of CRC cells and enabled activation of CSCs. However, after co-treatment with resveratrol, the malignancy of multicellular-TME reversed to HCT116. In addition, resveratrol reduced the secretion of T-lymphocyte/fibroblast (TNF-β, TGF-β3) proteins, antagonized the T-lymphocyte/fibroblast-promoting NF-κB activation, NF-κB nuclear translocation and thus the expression of NF-κB-promoting biomarkers, associated with proliferation, invasion and survival of CSCs in 3D-alginate cultures of HCT116 cells induced by TNF-β- or multicellular-TME, but not by Sirt1-ASO, indicating the central role of this enzyme in the anti-tumor function of resveratrol. Our results suggest that in vitro multicellular-TME promotes crosstalk between CRC and stromal cells to increase survival, migration of HCT116 and the resveratrol/Sirt1 axis suppresses this loop by modulating paracrine agent secretion and NF-κB signaling. Fibroblasts and T-lymphocytes are promising targets for resveratrol in the prevention of CRC metastasis.

Cosmeceutical potentials of Curcuma mangga Val. extract in human BJ fibroblasts against MMP1, MMP3, and MMP13

Oxidative stress, the disrupted oxidation-reduction mechanism in our body, is caused by the excessive exposure of free radicals and the impaired antioxidant defenses that can accelerate skin aging. Antioxidants can be obtained from nature, which are available widely in therapeutic-rich plants, such as white saffron (Curcuma mangga Val., denoted as C. mangga). Although many pieces of evidence reveal that C. mangga contains an abundance of phenolic compounds and has antioxidative effects, its cosmeceutical potentials remain unclear. The present study aimed to disclose the unexplored antiaging potentials of C. mangga extract (CME) in oxidative stress-induced human BJ fibroblasts with a focus on collagen protection against pro-inflammatory mediators MMP1, MMP3, and MMP13. The oxidative stress-induced cells were treated with CME and curcumin at different doses. The results showed that treatment using CME (25 μg/mL) could maintain the collagen contents up to 18.45 ± 0.68 μg/mL in H2O2-treated fibroblasts (only ~26.63% reduction in collagen contents), while the figure for the negative control was the lowest (12.79 μg/mL), showing a significant reduction in collagen contents by 49.13%. In addition, the gene expression of pro-inflammatory MMPs arose significantly in BJ fibroblasts after oxidative stress induction using 200 μM H2O2, in which the expression for MMP1, MMP3, and MMP13 increased by 7.10, 38.96, and 2.69 times, respectively. Interestingly, CME treatment (100 μg/mL) could effectively inhibit MMP1, MMP3, and MMP13 gene expression by 3.65, 34.62, and 2.02 times, respectively. In conclusion, CME showed favorable antiaging activities in H2O2-treated human BJ fibroblasts as confirmed by the low levels of gene expression of MPP1, MMP3, and MMP13 after treatment with CME.

Signalling mechanism(s) of epithelial-mesenchymal transition and cancer stem cells in tumour therapeutic resistance

Epithelial-mesenchymal transition (EMT) leads to tumour progression, including tumour metastasis, disease recurrence and therapy resistance. Cancer stem cells (CSCs) are a small group of cells that have the ability to undergo self-renewal and heterogeneous differentiation, which play a key role in the occurrence and development of cancer. EMT can promote tumour cells to develop stem cell characteristics, which makes tumours more difficult to treat. Therefore, exploring the role of EMT and CSCs in the metastasis of cancer is of great significance to guide tumour treatment and prognosis. In this review, we discuss EMT and CSCs in cancer progression and therapeutic resistance, with a special focus on the common characteristics and relationships between these processes, to explore the crucial relationships in the development of improved anti-tumour therapies.

AREAS COVERED

In this brief review article, the author has searched PubMed and Wikipedia for original research and reviewed articles to gather current information on the association of CSCs and EMT with therapeutic resistance characteristics, cancer growth and metastasis, which are believed to be regulated by the TGF-β, Wnt, Hedgehog (Hh), β-catenin, STAT3, Notch, and Nanog signalling pathways and other factors (miRNAs, microenvironment and additional cytokines).

Mesenchymal Stromal Cell-Derived Interleukin-6 Promotes Epithelial-Mesenchymal Transition and Acquisition of Epithelial Stem-Like Cell Properties in Ameloblastoma Epithelial Cells

Epithelial-mesenchymal transition (EMT), a biological process associated with cancer stem-like or cancer-initiating cell formation, contributes to the invasiveness, metastasis, drug resistance, and recurrence of the malignant tumors; it remains to be determined whether similar processes contribute to the pathogenesis and progression of ameloblastoma (AM), a benign but locally invasive odontogenic neoplasm. Here, we demonstrated that EMT- and stem cell-related genes were expressed in the epithelial islands of the most common histologic variant subtype, the follicular AM. Our results revealed elevated interleukin (IL)-6 signals that were differentially expressed in the stromal compartment of the follicular AM. To explore the stromal effect on tumor pathogenesis, we isolated and characterized both mesenchymal stromal cells (AM-MSCs) and epithelial cells (AM-EpiCs) from follicular AM and demonstrated that, in in vitro culture, AM-MSCs secreted a significantly higher level of IL-6 as compared to the counterpart AM-EpiCs. Furthermore, both in vitro and in vivo studies revealed that exogenous and AM-MSC-derived IL-6 induced the expression of EMT- and stem cell-related genes in AM-EpiCs, whereas such effects were significantly abrogated either by a specific inhibitor of STAT3 or ERK1/2, or by knockdown of Slug gene expression. These findings suggest that AM-MSC-derived IL-6 promotes tumor-stem like cell formation by inducing EMT process in AM-EpiCs through STAT3 and ERK1/2-mediated signaling pathways, implying a role in the etiology and progression of the benign but locally invasive neoplasm. Stem Cells 2017;35:2083-2094.

PARP1 expression, activity and ex vivo sensitivity to the PARP inhibitor, talazoparib (BMN 673), in chronic lymphocytic leukaemia

In chronic lymphocytic leukemia (CLL), mutation and loss of p53 and ATM abrogate DNA damage signalling and predict poorer response and shorter survival. We hypothesised that poly (ADP-ribose) polymerase (PARP) activity, which is crucial for repair of DNA breaks induced by oxidative stress or chemotherapy, may be an additional predictive biomarker and a target for therapy with PARP inhibitors.

We measured PARP activity in 109 patient-derived CLL samples, which varied widely (192 – 190052 pmol PAR/10⁶ cells) compared to that seen in healthy volunteer lymphocytes (2451 – 7519 pmol PAR/10⁶ cells). PARP activity was associated with PARP1 protein expression and endogenous PAR levels. PARP activity was not associated with p53 or ATM loss, Binet stage, IGHV mutational status or survival, but correlated with Bcl-2 and Rel A (an NF-kB subunit). Levels of 8-hydroxy-2′-deoxyguanosine in DNA (a marker of oxidative damage) were not associated with PAR levels or PARP activity. The potent PARP inhibitor, talazoparib (BMN 673), inhibited CD40L-stimulated proliferation of CLL cells at nM concentrations, independently of Binet stage or p53/ATM function.

PARP activity is highly variable in CLL and correlates with stress-induced proteins. Proliferating CLL cells (including those with p53 or ATM loss) are highly sensitive to the PARP inhibitor talazoparib.

Regulation of p53 and Rb links the alternative NF-κB pathway to EZH2 expression and cell senescence

There are two major pathways leading to induction of NF-κB subunits. The classical (or canonical) pathway typically leads to the induction of RelA or c-Rel containing complexes, and involves the degradation of IκBα in a manner dependent on IκB kinase (IKK) β and the IKK regulatory subunit NEMO. The alternative (or non-canonical) pathway, involves the inducible processing of p100 to p52, leading to the induction of NF-κB2(p52)/RelB containing complexes, and is dependent on IKKα and NF-κB inducing kinase (NIK). Here we demonstrate that in primary human fibroblasts, the alternative NF-κB pathway subunits NF-κB2 and RelB have multiple, but distinct, effects on the expression of key regulators of the cell cycle, reactive oxygen species (ROS) generation and protein stability. Specifically, following siRNA knockdown, quantitative PCR, western blot analyses and chromatin immunoprecipitation (ChIP) show that NF-κB2 regulates the expression of CDK4 and CDK6, while RelB, through the regulation of genes such as PSMA5 and ANAPC1, regulates the stability of p21WAF1 and the tumour suppressor p53. These combine to regulate the activity of the retinoblastoma protein, Rb, leading to induction of polycomb protein EZH2 expression. Moreover, our ChIP analysis demonstrates that EZH2 is also a direct NF-κB target gene. Microarray analysis revealed that in fibroblasts, EZH2 antagonizes a subset of p53 target genes previously associated with the senescent cell phenotype, including DEK and RacGAP1. We show that this pathway provides the major route of crosstalk between the alternative NF-κB pathway and p53, a consequence of which is to suppress cell senescence. Importantly, we find that activation of NF-κB also induces EZH2 expression in CD40L stimulated cells from Chronic Lymphocytic Leukemia patients. We therefore propose that this pathway provides a mechanism through which microenvironment induced NF-κB can inhibit tumor suppressor function and promote tumorigenesis.

Although the classical NF-κB pathway is frequently associated with the induction of cellular senescence and the senescence associated secretory phenotype (SASP), the role of the alternative NF-κB pathway, which is frequently activated in hematological malignancies as well as some solid tumors, has not been defined. We therefore investigated the role of the alternative NF-κB pathway in this process. Here we report that NF-κB2 and RelB, the effectors of the alternative NF-κB pathway, suppress senescence through inhibition of p53 activity. Using primary human fibroblasts, we demonstrate that this is accomplished through NF-κB2/RelB dependent control of a previously unknown pathway, incorporating regulation of CDK4 and 6 expression as well as regulators of p21WAF1 and p53 protein stability. Loss of NF-κB2/RelB results in suppression of retinoblastoma (Rb) tumour suppressor phosphorylation, which in turn leads to inhibition of EZH2 expression and de-repression of p53 activity. Interestingly, we find that CD40 ligand stimulation of cells from Chronic Lymphocytic Leukemia patients, which strongly induces the alternative NF-κB pathway, also induces EZH2 expression. We propose that the alternative NF-κB pathway can promote tumorigenesis through suppression of p53 dependent senescence, a process that may have relevance to cancer cells retaining wild type p53.

Curcumin suppresses crosstalk between colon cancer stem cells and stromal fibroblasts in the tumor microenvironment: potential role of EMT

OBJECTIVE

Interaction of stromal and tumor cells plays a dynamic role in initiating and enhancing carcinogenesis. In this study, we investigated the crosstalk between colorectal cancer (CRC) cells with stromal fibroblasts and the anti-cancer effects of curcumin and 5-Fluorouracil (5-FU), especially on cancer stem cell (CSC) survival in a 3D-co-culture model that mimics in vivo tumor microenvironment.

METHODS

Colon carcinoma cells HCT116 and MRC-5 fibroblasts were co-cultured in a monolayer or high density tumor microenvironment model in vitro with/without curcumin and/or 5-FU.

RESULTS

Monolayer tumor microenvironment co-cultures supported intensive crosstalk between cancer cells and fibroblasts and enhanced up-regulation of metastatic active adhesion molecules (β1-integrin, ICAM-1), transforming growth factor-β signaling molecules (TGF-β3, p-Smad2), proliferation associated proteins (cyclin D1, Ki-67) and epithelial-to-mesenchymal transition (EMT) factor (vimentin) in HCT116 compared with tumor mono-cultures. High density tumor microenvironment co-cultures synergistically increased tumor-promoting factors (NF-κB, MMP-13), TGF-β3, favored CSC survival (characterized by up-regulation of CD133, CD44, ALDH1) and EMT-factors (increased vimentin and Slug, decreased E-cadherin) in HCT116 compared with high density HCT116 mono-cultures. Interestingly, this synergistic crosstalk was even more pronounced in the presence of 5-FU, but dramatically decreased in the presence of curcumin, inducing biochemical changes to mesenchymal-epithelial transition (MET), thereby sensitizing CSCs to 5-FU treatment.

CONCLUSION

Enrichment of CSCs, remarkable activation of tumor-promoting factors and EMT in high density co-culture highlights that the crosstalk in the tumor microenvironment plays an essential role in tumor development and progression, and this interaction appears to be mediated at least in part by TGF-β and EMT. Modulation of this synergistic crosstalk by curcumin might be a potential therapy for CRC and suppress metastasis.

Biosynthesis and metabolism of β-d-salicin: A novel molecule that exerts biological function in humans and plants

β-d-Salicin 1 (Mahdi et al. [8]) is an interesting medicinal phytochemical that exhibits cross functions in plants and humans immunologically. This molecule 1 (Mahdi et al. [8]) has attracted the attention of scientists in various interdisciplinary fields, including chemistry, pharmacology and medicine. The biological cross functions of β-d-salicin 1 (Mahdi et al. [8]) serve in plant survival and healing processes via salicylic acid 2 (Pierpont [23]). Thus, this raise a question whether plant biosynthesis and human metabolism crosstalk to induce therapy via molecular recognition. If so, biotechnology and bioinformatics are significant techniques for new strategies in drug development. Thus, understanding the biosynthesis, metabolism and the cross-molecular setting of recognition may encourage further discussion and research on its medicinal and biological activity virtues.

The influence of Cox-2 and bioactive lipids on hematological cancers

Inflammation is implicated in the progression of multiple types of cancers including lung, colorectal, breast and hematological malignancies. Cyclooxygenases (Cox) -1 and -2 are important enzymes involved in the regulation of inflammation. Elevated Cox-2 expression is associated with a poor cancer prognosis. Hematological malignancies, which are among the top 10 most predominant cancers in the USA, express high levels of Cox-2. Current therapeutic approaches against hematological malignances are insufficient as many patients develop resistance or relapse. Therefore, targeting Cox-2 holds promise as a therapeutic approach to treat hematological malignancies. NSAIDs and Cox-2 selective inhibitors are anti-inflammatory drugs that decrease prostaglandin and thromboxane production while promoting the synthesis of specialized proresolving mediators. Here, we review the evidence regarding the applicability of NSAIDs, such as aspirin, as well as Cox-2 specific inhibitors, to treat hematological malignancies. Furthermore, we discuss how FDA-approved Cox inhibitors can be used as anti-cancer drugs alone or in combination with existing chemotherapeutic treatments.

The hexacarbonyldicobalt derivative of aspirin acts as a CO-releasing NSAID on malignant mesothelioma cells

The antiproliferative activity of the aspirin derivative [2-acetoxy-(2-propynyl)benzoate]hexacarbonyldicobalt (Co-ASS) and its analogue hexacarbonyl[μ-(2-ethylphenyl)methanol]dicobalt (Co-EPM) was investigated on malignant pleural mesothelioma (MPM) cell lines, having an epithelioid or a sarcomatoid phenotype. In sarcomatoid cell lines Co-ASS was more potent than Co-EPM and the prototypal metallo-drug cisplatin, and induced cell death through the intrinsic apoptotic pathway, associated with a strong NF-κB inhibition. In contrast, both Co-ASS and Co-EPM showed only a modest cytostatic activity against epithelioid MPM cells. Co-EPM induced an increase of senescent cells, while Co-ASS did not; the different outcomes were traced back to the organic (aspirin-like) portion of the molecule. Both Co-EPM and Co-ASS significantly reduced reactive oxygen/nitrogen species (ROS/RNS), and in turn nitrites, suggesting that the hexacarbonyldicobalt moiety may deliver CO within the cell, acting as a CO-releasing molecule (CO-RM). In perspective, Co-ASS would be better considered as a CO-NSAID agent (a CO-releasing molecule retaining the NSAID properties similar to NO- and H2S-NSAIDs) than as an antitumor drug candidate.

Pharmacological Importance of Simple Phenolic Compounds on Inflammation, Cell Proliferation and Apoptosis with a Special Reference to β-D-Salicin and Hydroxybenzoic Acid

Simple phenolic (SP) compounds are natural products that exhibit multiple pharmacological functions. The best known of these compounds is β-D-salicin, the first discovered phenolic glycoside and salicylic acid, or 2-hydroxybenzoic acid (2-HBA). Both of these compounds have attracted the interest of scientists in various interdisciplinary fields, including chemistry, pharmacology and medicine. Although β-D-salicin is found in various plants, it is often associated with willow, as it was first discovered in this species of plant. While the presence of glucose in β-D-salicin improves the physicochemical properties of the benzyl moiety, β-D-salicin itself does not have anti-inflammatory or anti-proliferative activity until it is metabolised into 2-HBA in the gastrointestinal tract and blood stream. Likewise, the majority of 2-acetoxybenzoic acid (2-ABA), or acetoxysalicylic acid also undergoes metabolic hydrolysis into 2-HBA. 2-HBA has been shown to play a role in modulating both inflammation and cancer partly through the inhibition of cyclooxygenase-2 (COX-2). It is now clear that 2-HBA most likely acts on the transcription factor NF-κB, which regulates the transcription of COX-2 thereby suppressing inflammation and cell proliferation and promoting apoptosis. Other phenolates, also exhibit anti-inflammation and anti-proliferation activities like the 4-hydroxybenzoate zinc (4-HBZn) complex, which was previously shown to preferentially inhibit COX-2 compared to 2-HBA and ASA. This review aims to collect all the available information related to β-D-salicin and other SP compounds in order to promote a new perspective of this interesting class of compounds and encourage further research into their pharmacological and clinical properties.

Apoptosis deregulation in CLL

The description of apoptosis and the identification of the genes that regulate it have proved pivotal to our understanding of how cancer cells accumulate and ultimately cause morbidity and mortality. It has become increasingly clear that in CLL the balance between the pro- and anti-apoptotic members of the BCL2 family of apoptotic regulatory proteins is critical in the development and clinical progression of CLL. Furthermore, the apoptotic potential of the CLL cell determines chemotherapy sensitivity and ultimately progression-free and overall survival. The unravelling of the BCL2 story in CLL has led to the development of a whole new class of therapeutic agents-the BH3 mimetics-which are significantly more targeted than conventional chemo-immunotherapy and therefore promise potent clinical activity coupled with reduced toxicity.

A cell culture system that mimics chronic lymphocytic leukemia cells microenvironment for drug screening and characterization

Chronic Lymphocytic Leukaemia (CLL) is an incurable disease that warrants new therapeutic treatments. CLL cells accumulate in the peripheral blood, in the bone marrow and in secondary lymphoid organs. Unlike circulating CLL cells, CLL cells resident in these last two compartments display high chemoresistance and proliferative capacity. Given the importance of the microenvironment in this disease, strategies that aim to develop new therapeutic agents need to consider this critical factor. Various cell culture conditions have been described that attempt to emulate either the different types of microenvironments in which CLL cells are found or an individual component of a particular microenvironment. Here, a methodology that partially mimics the interaction between CLL cells and the CD3+ CD4+ CD154+ T cells is described. Moreover, within this method, two protocols are presented and compared that may partially recapitulate different physiological states. The methodology can be exploited for target validation and drug development in CLL.

Indiosides G-K: steroidal glycosides with cytotoxic and anti-inflammatory activities from Solanum violaceum

Five new steroidal glycosides (1-5) and nine known compounds were isolated from Solanum violaceum. Indiosides G (1) and H (2) are spirostene saponins with an iso-type F ring, indioside I (3) is a spirostane saponin, and indiosides J (4) and K (5) are unusual furostanol saponins with a deformed F ring. These structures represent rare naturally occurring steroidal skeletons. The structures of the new compounds were elucidated using 1D and 2D spectroscopic techniques and acid hydrolysis. Compounds 2, 3, and 7-9 exhibited cytotoxic activity against six human cancer cell lines (HepG2, Hep3B, A549, Ca9-22, MDA-MB-231, and MCF-7) with IC(50) values of 1.83-8.04 μg/mL. Steroidal saponins 3, 8, and 9 showed inhibitory effects on superoxide anion generation with IC(50) values of 2.84 ± 0.18, 0.62 ± 0.03, and 1.62 ± 0.59 μg/mL, respectively. Saponins 8 and 9 also inhibited elastase release with IC(50) values of 111.05 ± 7.37 and 4.04 ± 0.51 μg/mL, respectively. Structure-activity relationship correlations of these compounds with respect to cytotoxic and anti-inflammatory effects are discussed.