Pro-angiogenic activity and vasculogenic mimicry in the tumor microenvironment by leptin in cancer

The acquired ability to induce the formation of a functional vasculature is a hallmark of cancer. Blood vessels in tumors are formed through various mechanisms, among the most important in cancer biology, angiogenesis, and vasculogenic mimicry have been described. Leptin is one of the main adipokines secreted by adipocytes in normal breast tissue and the tumor microenvironment. Here, we provide information on the relationship between leptin and the development of angiogenesis and vasculogenic mimicry in different types of cancer. Here, we report that leptin activates different pathways such as JAK-STAT3, MAPK/ERK, PKC, JNK, p38, and PI3K-Akt to induce the expression of various angiogenic factors and vasculogenic mimicry. In vivo models, leptin induces blood vessel formation through the PI3K-Akt-mTOR pathway. Interestingly, the relationship between leptin and vasculogenic mimicry was more significant in breast cancer. The information obtained suggests that leptin could be playing an essential role in tumor survival and metastasis through the induction of vascular mechanisms such as angiogenesis and vasculogenic mimicry; thus, leptin-induced pathways could be suggested as a promising therapeutic target.     

Plant-derived epigenetic modulators for cancer treatment and prevention

Carcinogenesis is a complex and multistep process that involves the accumulation of successive transformational events driven by genetic mutations and epigenetic alterations that affect major cellular processes and pathways such as proliferation, differentiation, invasion and survival. Massive deregulation of all components of the epigenetic machinery is a hallmark of cancer. These alterations affect normal gene regulation and impede normal cellular processes including cell cycle, DNA repair, cell growth, differentiation and apoptosis. Since epigenetic alterations appear early in cancer development and represent potentially initiating events during carcinogenesis, they are considered as promising targets for anti-cancer interventions by chemopreventive and chemotherapeutic strategies using epigenetically active agents. In this field, plant-derived compounds have shown promise. Here, we will give an overview of plant-derived compounds displaying anticancer properties that interfere with the epigenetic machinery.     

Mitochondria as therapeutic targets for cancer stem cells

Cancer stem cells(CSCs) are maintained by theirsomatic stem cells and are responsible for tumor initiation, chemoresistance, and metastasis. Evidence for the CSCs existence has been reported for a number of human cancers. The CSC mitochondria have been shown recently to be an important target for cancer treatment, but clinical significance of CSCs and their mitochondria properties remain unclear. Mitochondriatargeted agents are considerably more effective compared to other agents in triggering apoptosis of CSCs, as well as general cancer cells, via mitochondrial dysfunction. Mitochondrial metabolism is altered in cancer cells because of their reliance on glycolytic intermediates, which are normally destined for oxidative phosphorylation. Therefore, inhibiting cancer-specific modifications in mitochondrial metabolism, increasing reactive oxygen species production, or stimulating mitochondrial permeabilization transition could be promising new therapeutic strategies to activate cell death in CSCs as well, as in general cancer cells. This review analyzed mitochondrial function and its potential as a therapeutic target to induce cell death in CSCs. Furthermore, combined treatment with mitochondriatargeted drugs will be a promising strategy for the treatment of relapsed and refractory cancer.     

Macrophage regulation of tumor angiogenesis: implications for cancer therapy

This article reviews the evidence for macrophages playing an important role in the regulation of tumor angiogenesis. Findings in mouse models show that macrophages promote angiogenesis in tumors both by producing excessive amounts of proangiogenic factors and by physically assisting sprouting blood vessels to augment the complexity of the intra-tumoral vascular network. Recent studies however suggest that macrophages may be dispensable for the initiation of angiogenesis in tumors. Rather, these cells express proangiogenic programs that enhance the complexity of the tumor-associated vasculature, leading to aberrant, plethoric and dysfunctional angiogenesis. Gene expression and cell depletion studies further indicate that tumor-associated macrophages (TAMs) comprise phenotypically and functionally distinct subsets. This may reflect “education” of the macrophage phenotype by signals in some areas of the tumor microenvironment and/or TAM subsets derived from distinct macrophage precursors. Among the better characterized TAM subsets are the proangiogenic (TIE2⁺) and the angiostatic/inflammatory (CD11c⁺) macrophages, which coexist in tumors. Such antagonizing TAM subsets occupy distinct niches in the tumor microenvironment and are present at ratios that vary according to the tumor type and grade. Specifically targeting TAMs or reprogramming them from a proangiogenic to an angiostatic function may “normalize” the tumor vasculature and improve the efficacy of various anticancer therapies, including radiotherapy, chemotherapy and vascular-disrupting agents.     

Wood anatomy and heartwood formation in Neem (Axadirachta indica A. Juss.)

The wood of Azadirachta indica is diffuse porous. Axial parenchyma is paratracheal banded or vasicentric. Rays are uniseriate to multiseriate and heterocellular with procumbent and upright cells. There is a strong negative correlation between vessel member length and diameter. The vulnerability and mesomorphic values are different in two trees of almost the same age growing in the same locality. The vessel member wall has spiral thickenings on its inner surface. Axial and ray parenchyma cells and sometimes vessels and fibres of the heartwood show the presence of extractives. The necrobiosis of the parenchyma cells occurs at the heartwood boundary. Senescence and death of parenchyma cells are associated with depletion of starch grains and accumulation of extractives. There is a climacteric rise in succinate dehydrogenase and acid phosphatase activities at the sapwood-heartwood interface which may be associated with heartwood formation. Peroxidase activity is greater near the cambial zone, indicating its probable role in lignification.     

Targeting amino acid metabolism in cancer growth and anti-tumor immune response

Recent advances in amino acid metabolism have revealed that targeting amino acid metabolic enzymes in cancer therapy is a promising strategy for the development of novel therapeutic agents. There are currently several drugs in clinical trials that specifically target amino acid metabolic pathways in tumor cells. In the context of the tumor microenvironment,however,tumor cells form metabolic relationships with immune cells,and they oftencompete for common nutrients. Many tumors evolved to escape immune surveillance by taking advantage of their metabolic flexibility and redirecting nutrients for their own advantage. This review outlines the most recent advances in targeting amino acid metabolic pathways in cancer therapy while giving consideration to the impact these pathways may have on the anti-tumor immune response.     

Methyl jasmonate and its potential in cancer therapy

Methyl jasmonate (MeJa) is a naturally occurring hydrophobic oxylipin phytohormone. Early findings obtained from cancer cell lines suggest that MeJa is endowed with anticancer capabilities. It has been recently proposed that MeJa represents a novel agent that exhibits direct and selective actions against tumor cells without affecting normal human cells. In a previous study, I reported that MeJa itself is enough to result in the dysfunction of mitochondria and chloroplasts, as well as to activate cell death program (apoptosis), in the normal protoplasts of Arabidopsis thaliana. Indeed, this also holds true for other living plant systems in which senescence, hypersensitive response and oxidative stress have been found under MeJa action. Therefore, in this addendum to my previous article, I would like to stress that much more attention should be paid to the potential effect(s) of MeJa, or its derivatives, on healthy cells and tissues before it is used for clinical anticancer drugs, whether being used alone or in combination with other agents.     

Bioactive cationic peptides as potential agents for breast cancer treatment

Breast cancer continues to affect millions of women worldwide, and the number of new cases dramatically increases every year. The physiological causes behind the disease are still not fully understood. One in every 100 cases can occur in men, and although the frequency is lower than among women, men tend to have a worse prognosis of the disease. Various therapeutic alternatives to combat the disease are available. These depend on the type and progress of the disease, and include chemotherapy, radiotherapy, surgery, and cancer immunotherapy. However, there are several well-reported side effects of these treatments that have a significant impact on life quality, and patients either relapse or are refractory to treatment. This makes it necessary to develop new therapeutic strategies. One promising initiative are bioactive peptides, which have emerged in recent years as a family of compounds with an enormous number of clinical applications due to their broad spectrum of activity. They are widely distributed in several organisms as part of their immune system. The antitumoral activity of these peptides lies in a nonspecific mechanism of action associated with their interaction with cancer cell membranes, inducing, through several routes, bilayer destabilization and cell death. This review provides an overview of the literature on the evaluation of cationic peptides as potential agents against breast cancer under different study phases. First, physicochemical characteristics such as the primary structure and charge are presented. Secondly, information about dosage, the experimental model used, and the mechanism of action proposed for the peptides are discussed.     

Metabolic rewiring in cancer cells overexpressing the glucocorticoid-induced leucine zipper protein (GILZ): Activation of mitochondrial oxidative phosphorylation and sensitization to oxidative cell death induced by mitochondrial targeted drugs

Cancer cell metabolism is largely controlled by oncogenic signals and nutrient availability. Here, we highlighted that the glucocorticoid-induced leucine zipper (GILZ), an intracellular protein influencing many signaling pathways, reprograms cancer cell metabolism to promote proliferation. We provided evidence that GILZ overexpression induced a significant increase of mitochondrial oxidative phosphorylation as evidenced by the augmentation in basal respiration, ATP-linked respiration as well as respiratory capacity. Pharmacological inhibition of glucose, glutamine and fatty acid oxidation reduced the activation of GILZ-induced mitochondrial oxidative phosphorylation. At glycolysis level, GILZ-overexpressing cells enhanced the expression of glucose transporters in their plasmatic membrane and showed higher glycolytic reserve. ¹H NMR metabolites quantification showed an up-regulation of amino acid biosynthesis. The GILZ-induced metabolic reprograming is present in various cancer cell lines regardless of their driver mutations status and is associated with higher proliferation rates persisting under metabolic stress conditions. Interestingly, high levels of OXPHOS made GILZ-overexpressing cells vulnerable to cell death induced by mitochondrial pro-oxidants. Altogether, these data indicate that GILZ reprograms cancer metabolism towards mitochondrial OXPHOS and sensitizes cancer cells to mitochondria-targeted drugs with pro-oxidant activities.     

Fibroblast growth factor 8 increases breast cancer cell growth by promoting cell cycle progression and by protecting against cell death

Fibroblast growth factor 8 (FGF-8) is expressed in a large proportion of breast cancers, whereas its level in normal mammary gland epithelium is low. Previous studies have shown that FGF-8b stimulates breast cancer cell growth in vitro and in vivo. To explore the mechanisms by which FGF-8b promotes growth, we studied its effects on cell cycle regulatory proteins and signalling pathways in mouse S115 and human MCF-7 breast cancer cells. We also studied the effect of FGF-8b on cell survival. FGF-8b induced cell cycle progression and up-regulated particularly cyclin D1 mRNA and protein in S115 cells. Silencing cyclin D1 with siRNA inhibited most but not all FGF-8b-induced proliferation. Inhibition of the FGF-8b-activated ERK/MAPK pathway decreased FGF-8b-stimulated proliferation. Blocking the constitutively active PI3K/Akt and p38 MAPK pathways also lowered FGF-8b-induced cyclin D1 expression and proliferation. Corresponding results were obtained in MCF-7 cells. In S115 and MCF-7 mouse tumours, FGF-8b increased cyclin D1 and Ki67 levels. Moreover, FGF-8b opposed staurosporine-induced S115 cell death which effect was blocked by inhibiting the PI3K/Akt pathway but not the ERK/MAPK pathway. In conclusion, our results suggest that FGF-8b increases breast cancer cell growth both by stimulating cell cycle progression and by protecting against cell death.     

植物乳杆菌CGMCC8198干预脂代谢紊乱发挥肝癌防治作用

【背景】脂代谢异常是肝癌发生发展过程中重要的代谢事件,研究发现多种乳酸菌在调节糖脂代谢过程中发挥重要作用。【目的】探究植物乳杆菌CGMCC8198 (TCCC11824)是否会通过调节HMGCR/SMYD3脂代谢通路,进而对肝癌细胞的发生发展产生影响。【方法】采用不同浓度的(5、10、15μg/mL)植物乳杆菌CGMCC8198破碎上清液(Lactobacillus plantarum CGMCC 8198 Crushed Supernatant,LpS)处理HepG2细胞不同时间。利用蛋白免疫印迹(Western Blot)、油红染色以及实时定量荧光PCR(Real Time Quantitative PCR,RT-qPCR)等方法检测LpS对肝癌细胞脂肪变性及HMGCR/SMYD3脂代谢关键通路的影响;通过MTT法、细胞划痕实验、流式细胞术检测LpS对脂代谢紊乱过程中HepG2细胞增殖、迁移和凋亡的影响。【结果】LpS可以抑制脂代谢紊乱肝癌细胞中HMGCR、SMYD3、SREBP-2等基因的表达,同时也可以剂量依赖地抑制细胞增殖、迁移,促进细胞凋亡。【结论】LpS可以通过抑制脂代谢关键转录调控因子SREBP-2和HMGCR的表达来抑制肝癌细胞的脂代谢,进而促进肝癌细胞的内源性凋亡。     

The posttranslational modification of HDAC4 in cell biology: Mechanisms and potential targets

Histone deacetylase 4 (HDAC4) is a member of the HDACs family, its expression is closely related to the cell development. The cell is an independent living entity that undergoes proliferation, differentiation, senescence, apoptosis, and pathology, and each process has a strict and complex regulatory system. With deepening of its research, the expression of HDAC4 is critical in the life process. This review focuses on the posttranslational modification of HDAC4 in cell biology, providing an important target for future disease treatment.     

Intracellular redox state as determinant for melatonin antiproliferative vs cytotoxic effects in cancer cells

Abstract

Melatonin is an endogenous indolamine, classically known as a light/dark regulator. Besides classical functions, melatonin has also showed to have a wide range of antitumoral effects in numerous cancer experimental models. However, no definite mechanism has been described to explain the whole range of antineoplasic effects. Here we describe a dual effect of melatonin on intracellular redox state in relation to its antiproliferative vs cytotoxic actions in cancer cells. Thus, inhibition of proliferation correlates with a decrease on intracellular reactive oxygen species (ROS) and increase of antioxidant defences (antioxidant enzymes and intracellular gluthation,GSH levels), while induction of cell death correlates with an increase on intracellular ROS and decrease of antioxidant defences. Moreover, cell death can be prevented by other well-known antioxidants or can be increased by hydrogen peroxide. Thus, tumour cell fate will depend on the ability of melatonin to induce either an antioxidant environment—related to the antiproliferative effect or a prooxidant environment related to the cytotoxic effect.     

Clinical trials of antioxidants as cancer prevention agents: past, present, and future

The purpose of this review is to summarize the most important human clinical trials of antioxidants as cancer prevention agents conducted to date, provide an overview of currently ongoing studies, and discuss future steps needed to advance research in this field. To date there have been several large (at least 7000 participants) trials testing the efficacy of antioxidant supplements in preventing cancer. The specific agents (diet-derived direct antioxidants and essential components of antioxidant enzymes) tested in those trials included β-carotene, vitamin E, vitamin C, selenium, retinol, zinc, riboflavin, and molybdenum. None of the completed trials produced convincing evidence to justify the use of traditional antioxidant-related vitamins or minerals for cancer prevention. Our search of ongoing trials identified six projects at various stages of completion. Five of those six trials use selenium as the intervention of interest delivered either alone or in combination with other agents. The lack of success to date can be explained by a variety of factors that need to be considered in the next generation research. These factors include lack of good biological rationale for selecting specific agents of interest; limited number of agents tested to date; use of pharmacological, rather than dietary, doses; and insufficient duration of intervention and follow-up. The latter consideration underscores the need for alternative endpoints that are associated with increased risk of neoplasia (i.e., biomarkers of risk), but are detectable prior to tumor occurrence. Although dietary antioxidants are a large and diverse group of compounds, only a small proportion of candidate agents have been tested. In summary, the strategy of focusing on large high-budget studies using cancer incidence as the endpoint and testing a relatively limited number of antioxidant agents has been largely unsuccessful. This lack of success in previous trials should not preclude us from seeking novel ways of preventing cancer by modulating oxidative balance. On the contrary, the well demonstrated mechanistic link between excessive oxidative stress and carcinogenesis underscores the need for new studies. It appears that future large-scale projects should be preceded by smaller, shorter, less expensive biomarker-based studies that can serve as a link from mechanistic and observational research to human cancer prevention trials. These relatively inexpensive studies would provide human experimental evidence for the likely efficacy, optimum dose, and long-term safety of the intervention of interest that would then guide the design of safe, more definitive large-scale trials.     

Cytoprotective pyridinol antioxidants as potential therapeutic agents for neurodegenerative and mitochondrial diseases

As part of our ongoing efforts to identify compounds having potential utility in treating neurodegenerative and mitochondrial disorders, a series of pyridinol analogues have been prepared. The synthetic route employed for the preparation of the new analogues is different, and considerably more efficient, than that used in previously reported studies. The new route yields a pair of pyridinol regioisomers that can be readily separated and evaluated. Their ability to quench lipid peroxidation and reactive oxygen species (ROS), and to preserve mitochondrial membrane potential (Δψ_m) and support ATP synthesis is reported. The optimal side chain length was found to be 16 carbon atoms. The metabolic stability of those compounds having optimal biological activities was evaluated in vitro using bovine liver microsomes. The omission of any side chain hydroxyl group and introduction of an azetidine moiety at position 6 of the pyridinol redox core (8 and 9) increased their microsomal stability as compared to the exocyclic dimethylamino group. The favorable metabolic stability conferred by the azetidine moiety in compounds 8 and 9 makes these compounds excellent candidates for further evaluation.     

Flavoprotein miniSOG as a genetically encoded photosensitizer for cancer cells

Background

Genetically encoded photosensitizers are a promising optogenetic instrument for light-induced production of reactive oxygen species in desired locations within cells in vitro or whole body in vivo. Only two such photosensitizers are currently known, GFP-like protein KillerRed and FMN-binding protein miniSOG. In this work we studied phototoxic effects of miniSOG in cancer cells.

Methods

HeLa Kyoto cell lines stably expressing miniSOG in different localizations, namely, plasma membrane, mitochondria or chromatin (fused with histone H2B) were created. Phototoxicity of miniSOG was tested on the cells in vitro and tumor xenografts in vivo.

Results

Blue light induced pronounced cell death in all three cell lines in a dose-dependent manner. Caspase 3 activation was characteristic of illuminated cells with mitochondria- and chromatin-localized miniSOG, but not with miniSOG in the plasma membrane. In addition, H2B-miniSOG-expressing cells demonstrated light-induced activation of DNA repair machinery, which indicates massive damage of genomic DNA. In contrast to these in vitro data, no detectable phototoxicity was observed on tumor xenografts with HeLa Kyoto cell lines expressing mitochondria- or chromatin-localized miniSOG.

Conclusions

miniSOG is an excellent genetically encoded photosensitizer for mammalian cells in vitro, but it is inferior to KillerRed in the HeLa tumor.

General significance

This is the first study to assess phototoxicity of miniSOG in cancer cells. The results suggest an effective ontogenetic tool and may be of interest for molecular and cell biology and biomedical applications.     

Selective destabilization of tumor cells with pulsed electric and magnetic sequences: a preliminary report

Background: Various studies in vitro suggest that low electric and magnetic fields may modify cancer cell growth and recent studies in vivo have revealed anti-tumoral effects. After screening different tumor cell lines, we identified specific sequences of localized magnetic and electric fields (MESQ) that reduce cancer cell survival in vitro. This finding led us to design an experiment to determine the actual efficacy of above sequences in selectively destabilizing tumor cells and their effect on healthy cells.

Materials and Methods: We exposed the MCF7 cancer cell line and normal fibroblasts to MESQ for 1, 2, 3 and 6 hours, evaluating cell survival and induction of apoptosis.

Results: Exposure to MESQ reduced MCF7 survival, inducing apoptosis in a timedependent way, whereas fibroblasts were completely unaffected.

Conclusion: These results have promising implications for the treatment of cancer and warrant further research.     

Linking stemness with colorectal cancer initiation,progression, and therapy

The discovery of cancer stem cells caused a paradigm shift in the concepts of origin and development of colorectal cancer. Several unresolved questions remain in this field though. Are colorectal cancer stem cells the cause or an effect of the disease? How do cancer stem cells assist in colorectal tumor dissemination to distant organs? What are the molecular or environmental factors affecting the roles of these cells in colorectal cancer? Through this review, we investigate the key findings until now and attempt to elucidate the origins, physical properties, microenvironmental niches, as well as the molecular signaling network that support the existence, self-renewal, plasticity, quiescence, and the overall maintenance of cancer stem cells in colorectal cancer. Increasing data show that the cancer stem cells play a crucial role not only in the establishment of the primary colorectal tumor but also in the distant spread of the disease. Hence, we will also look at the mechanisms adopted by cancer stem cells to influence the development of metastasis and evade therapeutic targeting and its role in the overall disease prognosis. Finally, we will illustrate the importance of understanding the biology of these cells to develop improved clinical strategies to tackle colorectal cancer.     

Understanding the function of the tumor microenvironment,and compounds from marine organisms for breast cancer therapy

The pathology and physiology of breast cancer(BC),including metastasis,and drug resistance,is driven by multiple signaling pathways in the tumor microenvironment(TME),which hamper antitumor immunity.Recently,long non-coding RNAs have been reported to mediate pathophysiological developments such as metastasis as well as immune suppression within the TME.Given the complex biology of BC,novel personalized therapeutic strategies that address its diverse pathophysiologies are needed to improve clinical outcomes.In this review,we describe the advances in the biology of breast neoplasia,including cellular and molecular biology,heterogeneity,and TME.We review the role of novel molecules such as long non-coding RNAs in the pathophysiology of BC.Finally,we provide an up-to-date overview of anticancer compounds extracted from marine microorganisms,crustaceans,and fishes and their synergistic effects in combination with other anticancer drugs.Marine compounds are a new discipline of research in BC and offer a wide range of anti-cancer effects that could be harnessed to target the various pathways involved in BC development,thus assisting current therapeutic regimens.