Reactive Oxygen Species in Cancer Biology and Anticancer Therapy

Tong-Xie-Yao-Fang induces mitophagy in colonic epithelial cells to inhibit colitis-associated colorectal cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Based on the core pathogenesis of hepatosplenic disorder and qi transformation disorder in ulcerative colitis, Tong-Xie-Yao-Fang (TXYF) is a classical traditional Chinese medicine commonly used to treat ulcerative colitis. Our study revealed that it has the potential to prevent colitis-associated colorectal cancer, which embodies the academic concept in traditional Chinese medicine of treating the disease before it develops.

AIM OF THE STUDY

This study was aimed at evaluating the therapeutic role of TXYF in treating colitis-associated colorectal cancer and exploring its possible underlying mechanisms.

MATERIALS AND METHODS

A colitis-associated colorectal cancer model was established in mice using azoxymethane and dextran sulfate sodium salt to examine the therapeutic effect of TXYF. The mouse body weights were observed. Hematoxylin-eosin staining was used to evaluate mouse colon histopathology. Colon cancer cells and colon epithelial cells were used to explore the potential molecular mechanisms. The proliferation and apoptosis of cells were detected by CCK8 and cell colony assays, flow cytometry and western blotting. The epithelial-mesenchymal transition (EMT) and mitophagy markers were examined by immunohistochemistry, western blotting, quantitative real-time PCR and immunofluorescence staining.

RESULTS

TXYF inhibited the tumorigenesis of mice with colitis-associated colorectal cancer and the growth of inflammatory colon cells. TXYF induced mitophagy in colon cancer cells through the PTEN-induced putative kinase 1 (PINK1)/Parkin pathway to reverse EMT, which was consistent with the results in mice with colitis-associated colorectal cancer.

CONCLUSIONS

The results of the present study demonstrated that TXYF effectively inhibited the progression of colitis-associated colorectal cancer through the PINK1/Parkin pathway, which provides new evidence for prevention strategies for this disease.

Structure-Antitumor Activity Relationships of Aza- and Diaza-Anthracene-2,9,10-Triones and Their Partially Saturated Derivatives

The 1,8-Diazaanthracene-2,9,10-triones, their 5,8-dihydro derivatives, and 1,8-diazaanthracene-2,7,9,10-tetraones, structurally related to the diazaquinomycin family of natural products, were synthesized in a regioselective fashion employing Diels-Alder strategies. These libraries were studied for their cytotoxicity in a variety of human cancer cell lines in order to establish structure-activity relationships. From the results obtained, we conclude that some representatives of the 1,8-diazaanthracene-2,9,10-trione framework show potent and selective cytotoxicity against solid tumors. Similar findings were made for the related 1-azaanthracene-2,9,10-trione derivatives, structurally similar to the marcanine natural products, which showed improved activity over their natural counterparts. An enantioselective protocol based on the use of a SAMP-related chiral auxiliary derived was developed for the case of chiral 5-substituted 1,8-diazaanthracene-2,9,10-triones, and showed that their cytotoxicity was not enantiospecific.

The effect of L-carnitine on oocyte mitochondrial health and biomarkers on cyclophosphamide chemotherapy drug in mice

Improving oocyte competence during chemotherapy is widely known as a contributing factor to increasing the probability of fertility. Additionally, the role of cumulus cells in oocyte quality is of utmost importance. Therefore, this study was designed to simultaneously probe into the relative gene expression of oocytes and cumulus cells as biomarkers of oocyte quality with cyclophosphamide and L-carnitine treatment. A total of 60 adult NMRI mice were divided into four groups: control, L-carnitine (LC), cyclophosphamide (CP), and cyclophosphamide+L-carnitine (CP+LC). The relative mRNA expression levels of oocyte quality genes including growth differentiation factor 9 (Gdf9), hyaluronan synthase 2 (Has2), and mitochondrial sirtuin 3 (Sirt3) in oocytes, and genes involved in bilateral communication between cumulus cells and between the oocyte and its neighboring cumulus cells including connexin 37 (Cx37) and connexin 43 (Cx43) were detected by Real-time-PCR. DCFH-DA staining analyzed the level of intracellular ROS in oocytes. Under the influence of L-carnitine, Gdf9, Has2, Cx43, and Cx37 were significantly up-regulated (p ≤ 0.05). However, cyclophosphamide considerably reduced the expression of all these genes (p ≤ 0.05). The expression of the Sirt3 gene in the CP group increased significantly compared to the other groups (p ≤ 0.05). Analysis of fluorescent images revealed that the level of intracellular ROS in the cyclophosphamide group was significantly increased compared to the other groups (p ≤ 0.05), while it plummeted in the L-carnitine group (p ≤ 0.05). L-carnitine as an antioxidant can reduce the destructive effects of cyclophosphamide and enhance bilateral communications between oocytes and cumulus cells, and it may ultimately lead to an increase in the fertility rate.

Mesenchymal stem cells and ovarian cancer: Is there promising news?

Ovarian cancer (OC) is described as a heterogeneous complex condition with high mortality, weak prognosis, and late-stage presentation. OC has several subgroups based on different indices, like the origin and histopathology. The current treatments against OC include surgery followed by chemotherapy and radiotherapy; however, these methods have represented diverse side effects without enough effectiveness on OC. Recently, mesenchymal stem cell (MSC)-based therapy has acquired particular attention for treating diverse problems, such as cancer. These multipotent stem cells can be obtained from different sources, such as the umbilical cord, adipose tissues, bone marrow, and placenta, and their efficacy has been investigated against OC. Hence, in this narrative review, we aimed to review and discuss the present studies about the effects of various sources of MSCs on OC with a special focus on involved mechanisms.

A reactive oxygen species-related signature to predict prognosis and aid immunotherapy in clear cell renal cell carcinoma

Background

Clear cell renal cell carcinoma (ccRCC) is a malignant disease containing tumor-infiltrating lymphocytes. Reactive oxygen species (ROS) are present in the tumor microenvironment and are strongly associated with cancer development. Nevertheless, the role of ROS-related genes in ccRCC remains unclear.

Methods

We describe the expression patterns of ROS-related genes in ccRCC from The Cancer Genome Atlas and their alterations in genetics and transcription. An ROS-related gene signature was constructed and verified in three datasets and immunohistochemical staining (IHC) analysis. The immune characteristics of the two risk groups divided by the signature were clarified. The sensitivity to immunotherapy and targeted therapy was investigated.

Results

Our signature was constructed on the basis of glutamate-cysteine ligase modifier subunit (GCLM), interaction protein for cytohesin exchange factors 1 (ICEF1), methionine sulfoxide reductase A (MsrA), and strawberry notch homolog 2 (SBNO2) genes. More importantly, protein expression levels of GCLM, MsrA, and SBNO2 were detected by IHC in our own ccRCC samples. The high-risk group of patients with ccRCC suffered lower overall survival rates. As an independent predictor of prognosis, our signature exhibited a strong association with clinicopathological features. An accurate nomogram for improving the clinical applicability of our signature was constructed. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses showed that the signature was closely related to immune response, immune activation, and immune pathways. The comprehensive results revealed that the high-risk group was associated with high infiltration of regulatory T cells and CD8+ T cells and more benefited from targeted therapy. In addition, immunotherapy had better therapeutic effects in the high-risk group.

Conclusion

Our signature paved the way for assessing prognosis and developing more effective strategies of immunotherapy and targeted therapy in ccRCC.

Antiproliferative Evaluation of Novel 4-Imidazolidinone Derivatives as Anticancer Agent Which Triggers ROS-Dependent Apoptosis in Colorectal Cancer Cell

Colorectal cancer (CRC) is one of the most common causes of cancer-related death worldwide, and more therapies are needed to treat CRC. To discover novel CRC chemotherapeutic molecules, we used a series of previously synthesized novel imidazolidin-4-one derivatives to study their anticancer role in several cancer cell lines. Among these compounds, compound 9r exhibited the best anticancer activity in CRC cell lines HCT116 and SW620. We further investigated the anticancer molecular mechanism of compound 9r. We found that compound 9r induced mitochondrial pathway apoptosis in HCT116 and SW620 cells by inducing reactive oxygen species (ROS) production. Moreover, the elevated ROS generation activated the c-Jun N-terminal kinase (JNK) pathway, which further accelerated apoptosis. N-acetylcysteine (NAC), an antioxidant reagent, suppressed compound 9r-induced ROS production, JNK pathway activation, and apoptosis. Collectively, this research synthesized a series of imidazolidin-4-one derivatives, evaluated their anticancer activity, and explored the molecular mechanism of compound 9r-induced apoptosis in CRC cells. The present results suggest that compound 9r has a potential therapeutic role in CRC. Hence, it deserves further exploration as a lead compound for CRC treatment.

Thermo-Transient Receptor Potential Channels: Therapeutic Potential in Gastric Cancer

Over the last decade, researchers have found abnormal expression of transient receptor potential (TRP) channels. In particular, members of the thermally sensitive subclass (thermo-TRPs) are involved in many disease processes. Moreover, they have a vital role in the occurrence and development of gastric cancer (GC). Accordingly, thermo-TRPs constitute a major pharmacological target, and the elucidation of the mechanisms underlying their response to physiological stimuli or drugs is key for notable advances in GC treatment. Therefore, this paper summarizes the existing literature about thermo-TRP protein expression changes that are linked to the incidence and progression of GC. The review also discusses the implication of such association to pathology and cell physiology and identifies potential thermo-TRP protein targets for diagnosis and treatment of GC.

Synthesis Optimization of BaGdF5:x%Tb3+ Nanophosphors for Tunable Particle Size

X-ray photodynamic therapy (XPDT) is aimed at the treatment of deep-located malignant tumors thanks to the high penetration depth of X-rays. In XPDT therapy, it is necessary to use materials that effectively absorb X-rays and convert them into visible radiation-nanophosphors. Rare-earth elements, fluorides, in particular, doped BaGdF₅, are known to serve as efficient nanophosphor. On the other hand, the particle size of nanophosphors has a crucial impact on biodistribution, cell uptake, and cytotoxicity. In this work, we investigated various Tb:Gd ratios in the range from 0.1 to 0.5 and optimized the terbium content to achieve the maximum luminescence under X-ray excitation. The effect of temperature, composition of the ethylene glycol/water solvent, and the synthesis technique (solvothermal and microwave) on the size of the nanophosphors was explored. It was found that the synthesis techniques and the solvent composition had the greatest influence on the averaged particle size. By varying these two parameters, it is possible to tune the size of the nanophosphor particles, which make them suitable for biomedical applications.

Mitochondrial oxidative stress in the tumor microenvironment and cancer immunoescape: foe or friend?

The major concept of "oxidative stress" is an excess elevated level of reactive oxygen species (ROS) which are generated from vigorous metabolism and consumption of oxygen. The precise harmonization of oxidative stresses between mitochondria and other organelles in the cell is absolutely vital to cell survival. Under oxidative stress, ROS produced from mitochondria and are the major mediator for tumorigenesis in different aspects, such as proliferation, migration/invasion, angiogenesis, inflammation, and immunoescape to allow cancer cells to adapt to the rigorous environment. Accordingly, the dynamic balance of oxidative stresses not only orchestrate complex cell signaling events in cancer cells but also affect other components in the tumor microenvironment (TME). Immune cells, such as M2 macrophages, dendritic cells, and T cells are the major components of the immunosuppressive TME from the ROS-induced inflammation. Based on this notion, numerous strategies to mitigate oxidative stresses in tumors have been tested for cancer prevention or therapies; however, these manipulations are devised from different sources and mechanisms without established effectiveness. Herein, we integrate current progress regarding the impact of mitochondrial ROS in the TME, not only in cancer cells but also in immune cells, and discuss the combination of emerging ROS-modulating strategies with immunotherapies to achieve antitumor effects.

Apple pectin-based Zataria multiflora essential oil (ZEO) nanoemulsion: An approach to enhance ZEO DNA damage induction in breast cancer cells as in vitro and in silico studies reveal

Zataria multiflora essential oil (ZEO) is a natural complex of compounds with a high apoptotic potential against breast cancer cells and minor toxicity toward normal cells; however, similar to many essential oils, ZEO utilization in pharmaceutical industries has limitations due to its labile and sensitive ingredients. Nanoemulsification based on natural polymers is one approach to overcome this issue. In this study, an apple pectin-ZEO nanoemulsion (AP-ZEONE) was prepared and its morphology, FTIR spectra, and physical properties were characterized. Furthermore, it was shown that AP-ZEONE substantially suppresses the viability of MDA-MB-231, T47D, and MCF-7 breast cancer cells. AP-ZEONE significantly induced apoptotic morphological alterations and DNA fragmentation as confirmed by fluorescent staining and TUNEL assay. Moreover, AP-ZEONE induced apoptosis in MDA-MB-231 cells by loss of mitochondrial membrane potential (ΔΨm) associated with the accumulation of reactive oxygen species (ROS), G2/M cell cycle arrest, and DNA strand breakage as flow cytometry, DNA oxidation, and comet assay analysis revealed, respectively. Spectroscopic and computational studies also confirmed that AP-ZEONE interacts with genomic DNA in a minor groove/partial intercalation binding mode. This study demonstrated the successful inhibitory effect of AP-ZEONE on metastatic breast cancer cells, which may be beneficial in the therapy process.

Single-cell characterization of malignant phenotypes and microenvironment alteration in retinoblastoma

Retinoblastoma (RB) is the most common primary intraocular malignancy of childhood. It is known that the tumor microenvironment (TME) regulates tumorigenesis and metastasis. However, how the malignant progression in RB is determined by the heterogeneity of tumor cells and TME remains uncharacterized. Here, we conducted integrative single-cell transcriptome and whole-exome sequencing analysis of RB patients with detailed pathological and clinical measurements. By single-cell transcriptomic sequencing, we profiled around 70,000 cells from tumor samples of seven RB patients. We identified that the major cell types in RB were cone precursor-like (CP-like) and MKI67+ cone precursor (MKI67+ CP) cells. By integrating copy number variation (CNV) analysis, we found that RB samples had large clonal heterogeneity, where the malignant MKI67+ CP cells had significantly larger copy number changes. Enrichment analysis revealed that the conversion of CP-like to MKI67+ CP resulted in the loss of photoreceptor function and increased cell proliferation ability. The TME in RB was composed of tumor-associated macrophages (TAMs), astrocyte-like, and cancer-associated fibroblasts (CAFs). Particularly, during the invasion process, TAMs created an immunosuppressive environment, in which the proportion of TAMs decreased, M1-type macrophage was lost, and the TAMs-related immune functions were depressed. Finally, we identified that TAMs regulated tumor cells through GRN and MIF signaling pathways, while TAMs self-regulated through inhibition of CCL and GALECTIN signaling pathways during the invasion process. Altogether, our study creates a detailed transcriptomic map of RB with single-cell characterization of malignant phenotypes and provides novel molecular insights into the occurrence and progression of RB.

Life Entrapped in a Network of Atavistic Attractors: How to Find a Rescue

In view of unified cell bioenergetics, cell bioenergetic problems related to cell overenergization can cause excessive disturbances in current cell fate and, as a result, lead to a change of cell-fate. At the onset of the problem, cell overenergization of multicellular organisms (especially overenergization of mitochondria) is solved inter alia by activation and then stimulation of the reversible Crabtree effect by cells. Unfortunately, this apparently good solution can also lead to a much bigger problem when, despite the activation of the Crabtree effect, cell overenergization persists for a long time. In such a case, cancer transformation, along with the Warburg effect, may occur to further reduce or stop the charging of mitochondria by high-energy molecules. Understanding the phenomena of cancer transformation and cancer development has become a real challenge for humanity. To date, many models have been developed to understand cancer-related mechanisms. Nowadays, combining all these models into one coherent universal model of cancer transformation and development can be considered a new challenge. In this light, the aim of this article is to present such a potentially universal model supported by a proposed new model of cellular functionality evolution. The methods of fighting cancer resulting from unified cell bioenergetics and the two presented models are also considered.

The Rare-Earth Elements Doping of BaGdF5 Nanophosphors for X-ray Photodynamic Therapy

It is known that the initiation of photodynamic therapy (PDT) in deep-seated tumors requires the use of X-rays to activate the reactive oxygen species generation in deep tissues. The aim of this paper is to synthesize X-ray nanophosphors and analyze their structural and luminescence characteristics to push the PDT process deep into the body. The article deals with BaGdF5:Eu3+, BaGdF5:Sm3+, and BaGdF5:Tb3+ nanophosphors synthesized using microwave synthesis. It is found that the nanoparticles are biocompatible and have sizes 5-17 nm. However, according to the analysis of X-ray excited optical luminescence, BaGdF5:Sm3+ nanophosphors will not be effective for treating deep-seated tumors. Thus, BaGdF5:Eu3+ and BaGdF5:Tb3+ nanoparticles meet the requirements for the subsequent production of nanocomposites based on them that can be used in X-ray photodynamic therapy.

Insights into the Role of Oxidative Stress in Ovarian Cancer

Oxidative stress (OS) arises when the body is subjected to harmful endogenous or exogenous factors that overwhelm the antioxidant system. There is increasing evidence that OS is involved in a number of diseases, including ovarian cancer (OC). OC is the most lethal gynecological malignancy, and risk factors include genetic factors, age, infertility, nulliparity, microbial infections, obesity, smoking, etc. OS can promote the proliferation, metastasis, and therapy resistance of OC, while high levels of OS have cytotoxic effects and induce apoptosis in OC cells. This review focuses on the relationship between OS and the development of OC from four aspects: genetic alterations, signaling pathways, transcription factors, and the tumor microenvironment. Furthermore, strategies to target aberrant OS in OC are summarized and discussed, with a view to providing new ideas for clinical treatment.

Unraveling How Tumor-Derived Galectins Contribute to Anti-Cancer Immunity Failure

Simple Summary

This review compiles our current knowledge of one of the main pathways activated by tumors to escape immune attack. Indeed, it integrates the current understanding of how tumor-derived circulating galectins affect the elicitation of effective anti-tumor immunity. It focuses on several relevant topics: which are the main galectins produced by tumors, how soluble galectins circulate throughout biological liquids (taking a body-settled gradient concentration into account), the conditions required for the galectins’ functions to be accomplished at the tumor and tumor-distant sites, and how the physicochemical properties of the microenvironment in each tissue determine their functions. These are no mere semantic definitions as they define which functions can be performed in said tissues instead. Finally, we discuss the promising future of galectins as targets in cancer immunotherapy and some outstanding questions in the field.

Abstract

Current data indicates that anti-tumor T cell-mediated immunity correlates with a better prognosis in cancer patients. However, it has widely been demonstrated that tumor cells negatively manage immune attack by activating several immune-suppressive mechanisms. It is, therefore, essential to fully understand how lymphocytes are activated in a tumor microenvironment and, above all, how to prevent these cells from becoming dysfunctional. Tumors produce galectins-1, -3, -7, -8, and -9 as one of the major molecular mechanisms to evade immune control of tumor development. These galectins impact different steps in the establishment of the anti-tumor immune responses. Here, we carry out a critical dissection on the mechanisms through which tumor-derived galectins can influence the production and the functionality of anti-tumor T lymphocytes. This knowledge may help us design more effective immunotherapies to treat human cancers.

Role of NRF2 in Lung Cancer

The gene expression program induced by NRF2 transcription factor plays a critical role in cell defense responses against a broad variety of cellular stresses, most importantly oxidative stress. NRF2 stability is fine-tuned regulated by KEAP1, which drives its degradation in the absence of oxidative stress. In the context of cancer, NRF2 cytoprotective functions were initially linked to anti-oncogenic properties. However, in the last few decades, growing evidence indicates that NRF2 acts as a tumor driver, inducing metastasis and resistance to chemotherapy. Constitutive activation of NRF2 has been found to be frequent in several tumors, including some lung cancer sub-types and it has been associated to the maintenance of a malignant cell phenotype. This apparently contradictory effect of the NRF2/KEAP1 signaling pathway in cancer (cell protection against cancer versus pro-tumoral properties) has generated a great controversy about its functions in this disease. In this review, we will describe the molecular mechanism regulating this signaling pathway in physiological conditions and summarize the most important findings related to the role of NRF2/KEAP1 in lung cancer. The focus will be placed on NRF2 activation mechanisms, the implication of those in lung cancer progression and current therapeutic strategies directed at blocking NRF2 action.

Nanomaterials for Deep Tumor Treatment

According to statistics, cancer is the second leading cause of death in the world. Thus, it is important to solve this medical and social problem by developing new effective methods for cancer treatment. An alternative to more well-known approaches, such as radiotherapy and chemotherapy, is photodynamic therapy (PDT), which is limited to the shallow tissue penetration (< 1 cm) of visible light. Since the PDT process can be initiated in deep tissues by X-ray irradiation (X-ray induced PDT, or XPDT), it has a great potential to treat tumors in internal organs. The article discusses the principles of therapies. The main focus is on various nanoparticles used with or without photosensitizers, which allow the conversion of X-ray irradiation into UV-visible light. Much attention is given to the synthesis of nanoparticles and analysis of their characteristics, such as size and spectral features. The results of in vitro and in vivo experiments are also discussed.

What Animal Cancers teach us about Human Biology

Cancers in animals present a large, underutilized reservoir of biomedical information with critical implication for human oncology and medicine in general. Discussing two distinct areas of tumour biology in non-human hosts, we highlight the importance of these findings for our current understanding of cancer, before proposing a coordinated strategy to harvest biomedical information from non-human resources and translate it into a clinical setting. First, infectious cancers that can be transmitted as allografts between individual hosts, have been identified in four distinct, unrelated groups, dogs, Tasmanian devils, Syrian hamsters and, surprisingly, marine bivalves. These malignancies might hold the key to improving our understanding of the interaction between tumour cell and immune system and, thus, allow us to devise novel treatment strategies that enhance anti-cancer immunosurveillance, as well as suggesting more effective organ and stem cell transplantation strategies. The existence of these malignancies also highlights the need for increased scrutiny when considering the existence of infectious cancers in humans. Second, it has long been understood that no linear relationship exists between the number of cells within an organism and the cancer incidence rate. To resolve what is known as Peto's Paradox, additional anticancer strategies within different species have to be postulated. These naturally occurring idiosyncrasies to avoid carcinogenesis represent novel potential therapeutic strategies.

Biochemical pathways of copper complexes: progress over the past 5 years

Copper is an essential trace element with vital roles in many metalloenzymes; it is also prominent among nonplatinum anticancer metallodrugs. Copper-based complexes are endogenously biocompatible, tenfold more potent than cisplatin, exhibit fewer adverse effects, and have a wide therapeutic window. In cancer biology, copper acts as an antitumor agent by inhibiting cancer via multiple pathways. Herein, we present an overview of advances in copper complexes as 'lead' antitumor drug candidates, and in understanding their biochemical and pharmacological pathways over the past 5 years. This review will help to develop more efficacious therapeutics to improve clinical outcomes for cancer treatments.

Catalase immunoexpression in colorectal lesions

Introduction

It is generally accepted that the gastrointestinal tract, and especially the colon, is constantly exposed to reactive oxygen species (ROS) that may be responsible for the appearance of genetic mutations. To keep a steady-state control over ROS production-detoxification, organisms have evolved a defensive system. Nevertheless, many reports have described decreased level of antioxidant enzymes, especially catalase (CAT), in cancer tissues.

Aim

In this work we try to assess the immunohistochemical expression of CAT protein in colorectal adenoma and adenocarcinoma samples.

Material and methods

This study was performed on resected specimens obtained from 122 patients who had undergone surgical resection for colorectal cancer, and from 120 patients who had undergone colonoscopy. Paraffin- embedded, 4 µm-thick tissue sections were stained for rabbit polyclonal anti CAT antibody obtained from GeneTex (cat. no. GTX110704).

Results

In adenoma strong immunoexpression was detected mainly in infiltrating mononuclear cells within lamina propria. High expression of CAT was significantly associated with grade of dysplasia (high grade vs. low grade, p = 0.037). In adenocarcinoma samples, the high level of CAT immunoexpression was significantly correlated with histological grade of tumour (G1 vs. G2 vs. G3, p = 0.001) and depth of invasion (T1 vs. T2 vs. T3 vs. T4, p = 0.003).

Conclusions

Development of colorectal cancer is associated with increased expression of CAT in the stage of adenoma and decreased expression in the stage of adenocarcinoma.

Potential use of n-3 PUFAs to prevent oxidative stress-derived ototoxicity caused by platinum-based chemotherapy

Platinum-based compounds are widely used for the treatment of different malignancies due to their high effectiveness. Unfortunately, platinum-based treatment may lead to ototoxicity, an often-irreversible side effect without a known effective treatment and prevention plan. Platinum-based compound-related ototoxicity results mainly from the production of toxic levels of reactive oxygen species (ROS) rather than DNA-adduct formation, which has led to test strategies based on direct ROS scavengers to ameliorate hearing loss. However, favorable clinical results have been associated with several complications, including potential interactions with chemotherapy efficacy. To understand the contribution of the different cytotoxic mechanisms of platinum analogues on malignant cells and auditory cells, the particular susceptibility and response of both kinds of cells to molecules that potentially interfere with these mechanisms, is fundamental to develop innovative strategies to prevent ototoxicity without affecting antineoplastic effects. The n-3 long-chain polyunsaturated fatty acids (n-3 PUFAs) have been tried in different clinical settings, including with cancer patients. Nevertheless, their use to decrease cisplatin-induced ototoxicity has not been explored to date. In this hypothesis paper, we address the mechanisms of platinum compounds-derived ototoxicity, focusing on the differences between the effects of these compounds in neoplastic versus auditory cells. We discuss the basis for a strategic use of n-3 PUFAs to potentially protect auditory cells from platinum-derived injury without affecting neoplastic cells and chemotherapy efficacy.

The Role of Oxidative Stress and Its Counteractive Utility in Colorectal Cancer (CRC)

An altered redox status accompanied by an elevated generation of reactive oxygen/nitrogen species (ROS/RNS) has been implicated in a number of diseases including colorectal cancer (CRC). CRC, being one of the most common cancers worldwide, has been reported to be associated with multiple environmental and lifestyle factors (e.g., dietary habits, obesity, and physical inactivity) and harboring heightened oxidative stress that results in genomic instability. Although under normal condition ROS regulate many signal transduction pathways including cell proliferation and survival, overwhelming of the antioxidant capacity due to metabolic abnormalities and oncogenic signaling leads to a redox adaptation response that imparts drug resistance. Nevertheless, excessive reliance on elevated production of ROS makes the tumor cells increasingly vulnerable to further ROS insults, and the abolition of such drug resistance through redox perturbation could be instrumental to preferentially eliminate them. The goal of this review is to demonstrate the evidence that links redox stress to the development of CRC and assimilate the most up-to-date information that would facilitate future investigation on CRC-associated redox biology. Concomitantly, we argue that the exploitation of this distinct biochemical property of CRC cells might offer a fresh avenue to effectively eradicate these cells.

Chrysophyllum cainito stem bark extract induces apoptosis in Human hepatocarcinoma HepG2 cells through ROS-mediated mitochondrial pathway

Hepatocellular carcinoma is the most common type of primary liver cancer in humans. This study aimed to demonstrate anticancer properties of an aqueous extract from Chrysophyllum cainito stem bark (CE) and its underlying mechanisms. Our MTT assay results showed that CE significantly reduced human hepatocellular carcinoma (HepG2) cell viability with the IC₅₀of 100 µg/mL, while human dermal primary fibroblast (HDFa) cells showed less susceptibility in every concentration tested. Determined by Annexin V staining, the proportion of apoptotic HepG2 cells increased in a dose-dependent fashion after 24 hour-exposure of CE. The results from Western blot analysis confirmed that CE reduced procaspase-3, suggesting apoptosis by activating caspase-3 cleavage. Using the DCFH-DA and DiOC6 fluorescent probes, it was found that CE significantly stimulated the generation of reactive oxygen species (ROS) and reduced mitochondrial membrane potential (Δψ_m), respectively. According to cell cycle analysis, CE (100 µg/mL) profoundly increased the percentage of cells in the sub-G1 phase, indicating cell apoptosis. These data suggest that CE induces apoptosis and cell death in human hepatocellular carcinoma via generation of intracellular ROS and disruption of Δψm. This is the first demonstration of the anticancer activity with proposed underlying mechanism of CE in liver cancer cells.

Reactive oxygen species in cancer: a paradox between pro- and anti-tumour activities

Cancer constitutes a group of heterogeneous diseases that share common features. They involve the existence of altered cellular pathways which result in uncontrolled cell proliferation. Deregulation of production and/or elimination of reactive oxygen species (ROS) appear to be a relevant issue in most of them. ROS have a dual role in cell metabolism: they are compromised in normal cellular homeostasis, but their overproduction has been reported to promote oxidative stress (OS), a process that may induce the damage of cell structures. ROS accumulation is implicated in the activation of signaling pathways that promote cell proliferation and metabolic adaptations to tumour growth. One characteristic of cancer cells is the sensitivity to OS, which often results from the combination of high anabolic needs and hypoxic growth conditions. However, there is still no clear evidence about the levels of oxidant species that promote cellular transformation or, otherwise, if OS induction could be adequate as an antitumour therapeutic tool. There is a need for novel therapeutic strategies based on the new knowledge of cancer biology. Targeting oncogenic molecular mechanisms with non-classical agents and/or natural compounds would be beneficial as chemoprevention or new adjuvant therapies. In addition, epigenetics and environment, and particularly dietary factors may influence the development and prevention of cancer. This article will present a revision of the current research about molecular aspects proposed to be involved in the anticancer features of oxidant and antioxidant-based therapies targeting cancer cells, and their participation in the balance of oxidative species and cancer cell death.

Kanamycin-induced production of 2',3'-cyclic AMP in Escherichia coli

In contrast to the well-characterized second messenger adenosine 3',5'-cyclic monophosphate (3',5'-cAMP), the biological roles of its isomer 2',3'-cAMP remain largely unknown, especially in bacteria. Recent work reported that RNase I-dependent elevation of 2',3'-cNMP levels in Escherichia coli correlated with reduced biofilm production, and separate studies demonstrated E. coli ribonuclease activation in response to aminoglycoside antibiotics. Here we report that E. coli produced 2',3'-cAMP in response to kanamycin at sub-inhibitory levels. Surprisingly, other aminoglycosides like streptomycin or gentamicin did not generate levels of 2',3'-cAMP detectable by ³¹P NMR. Interestingly, because 2',3'-cAMP is also produced in E. coli strains expressing a plasmid-encoded kanamycin resistance gene but not by other ribosome-targeting antibiotics, this kanamycin-specific production may not reflect disrupted protein synthesis. Overall, this finding provides a link between aminoglycoside-induced ribonuclease activity and 2',3'-cAMP production in E. coli.

Warburg and Beyond: The Power of Mitochondrial Metabolism to Collaborate or Replace Fermentative Glycolysis in Cancer

A defining hallmark of tumor phenotypes is uncontrolled cell proliferation, while fermentative glycolysis has long been considered as one of the major metabolic pathways that allows energy production and provides intermediates for the anabolic growth of cancer cells. Although such a vision has been crucial for the development of clinical imaging modalities, it has become now evident that in contrast to prior beliefs, mitochondria play a key role in tumorigenesis. Recent findings demonstrated that a full genetic disruption of the Warburg effect of aggressive cancers does not suppress but instead reduces tumor growth. Tumor growth then relies exclusively on functional mitochondria. Besides having fundamental bioenergetic functions, mitochondrial metabolism indeed provides appropriate building blocks for tumor anabolism, controls redox balance, and coordinates cell death. Hence, mitochondria represent promising targets for the development of novel anti-cancer agents. Here, after revisiting the long-standing Warburg effect from a historic and dynamic perspective, we review the role of mitochondria in cancer with particular attention to the cancer cell-intrinsic/extrinsic mechanisms through which mitochondria influence all steps of tumorigenesis, and briefly discuss the therapeutic potential of targeting mitochondrial metabolism for cancer therapy.

Sanguinarine Induces Apoptosis in Papillary Thyroid Cancer Cells via Generation of Reactive Oxygen Species

Sanguinarine (SNG), a natural compound with an array of pharmacological activities, has promising therapeutic potential against a number of pathological conditions, including malignancies. In the present study, we have investigated the antiproliferative potential of SNG against two well-characterized papillary thyroid cancer (PTC) cell lines, BCPAP and TPC-1. SNG significantly inhibited cell proliferation of PTC cells in a dose and time-dependent manner. Western blot analysis revealed that SNG markedly attenuated deregulated expression of p-STAT3, without affecting total STAT3, and inhibited growth of PTC via activation of apoptotic and autophagy signaling cascade, as SNG treatment of PTC cells led to the activation of caspase-3 and caspase-8; cleavage of PARP and activation of autophagy markers. Further, SNG-mediated anticancer effects in PTC cells involved the generation of reactive oxygen species (ROS) as N-acetyl cysteine (NAC), an inhibitor of ROS, prevented SNG-mediated antiproliferative, apoptosis and autophagy inducing action. Interestingly, SNG also sensitized PTC cells to chemotherapeutic drug cisplatin, which was inhibited by NAC. Finally, SNG suppressed the growth of PTC thyrospheres and downregulated stemness markers ALDH2 and SOX2. Altogether, the findings of the current study suggest that SNG has anticancer potential against PTC cells as well its derived cancer stem-like cells, most likely via inactivation of STAT3 and its associated signaling molecules.

Activation of JNK and p38 in MCF-7 Cells and the In Vitro Anticancer Activity of Alnus hirsuta Extract

JNK and p38 are important mitogen-activated protein kinases (MAPKs) that respond to stress stimuli. The stress-activated MAPKs associated with apoptotic cell death play vital roles in mammalian cells. Alnus hirsuta, which contains abundant diarylheptanoids derivatives, is a valuable medicinal plant. The CHCl3 extract (AHC) containing platyphyllenone (1) and platyphyllone (3) as main compounds showed in vitro anticancer effects. We report the biological activities of A. hirsuta extract associated with the regulation of apoptosis and JNK and p38 in MCF-7 breast cancer cells. Levels of phospho-JNK and phospho-p38 by AHC treatment were evaluated by enzyme-linked immunosorbent assay (ELISA). ROS production, apoptotic effect, and DNA contents of the cells were measured by flow cytometry. The two diarylheptanoids 1 and 3 and the AHC extract exhibited cytotoxic effects on MCF-7 cells in MTT assay, with IC50 values of 18.1, 46.9, 260.0 μg/mL, respectively. AHC induced ROS generation and elevated the endogenous levels of phospho-JNK and phospho-p38. AHC resulted in apoptosis and cell cycle arrest. We suggest that the antitumor effect of A. hirsuta extract is achieved by apoptosis promotion and cell cycle arrest mediated by the activation of JNK and p38 signaling pathway via ROS generation.

Oxoisoaporphines and Aporphines: Versatile Molecules with Anticancer Effects

Cancer is a disease that involves impaired genome stability with a high mortality index globally. Since its discovery, many have searched for effective treatment, assessing different molecules for their anticancer activity. One of the most studied sources for anticancer therapy is natural compounds and their derivates, like alkaloids, which are organic molecules containing nitrogen atoms in their structure. Among them, oxoisoaporphine and sampangine compounds are receiving increased attention due to their potential anticancer effects. Boldine has also been tested as an anticancer molecule. Boldine is the primary alkaloid extract from boldo, an endemic tree in Chile. These compounds and their derivatives have unique structural properties that potentially have an anticancer mechanism. Different studies showed that this molecule can target cancer cells through several mechanisms, including reactive oxygen species generation, DNA binding, and telomerase enzyme inhibition. In this review, we summarize the state-of-art research related to oxoisoaporphine, sampangine, and boldine, with emphasis on their structural characteristics and the relationship between structure, activity, methods of extraction or synthesis, and anticancer mechanism. With an effective cancer therapy still lacking, these three compounds are good candidates for new anticancer research.

Anticancer and genotoxicity effect of (Clausena lansium (Lour.) Skeels) Peel ZnONPs on neuroblastoma (SH-SY5Y) cells through the modulation of autophagy mechanism

Nanotechnology is an emerged field to develop the plant mediated metal based nanodrugs by green method. In this current study, the zinc oxide metal based nanoparticles were developed using (Clausena lansium (Lour.) Skeels) Peel aqueous extracts and zinc nitrate. The C.L extract zinc nanoparticleswere indicated by the sharp peak seen at 350 nm utilizing the Ultraviolet-Visible spectroscopy (UV-Vis). The high peaks indicate the presence of phytochemicals and its functional groups in ZnONPs were studied by the Fourier Transform Infrared Spectroscopy (FT-IR). The X-Ray Diffraction analysis (XRD) explores the pattern and structure of ZnONPs as spherical and base-centered monoclinic crystalline shapes. The C.L extract with Zn nanoparticles were spherical in nature and the size of the synthesized particles were about 28.42 nm respectively. The autophagy (Beclin-1, LC3-I, LC3-II and ATG4B) and apoptotic (Bax, Bcl-2 and Caspase-3) proteins were regulated by the treatment with ZnONPs in SH-SY5Y neuroblastoma cells. The DNA loss or damage was occurred in the ZnONPs treatment and it was performed using Comet assay. The ZnONPs treatment generates the ROS in the cells and decreased its stability and viability. Addition of NAC prevents ROS in the cultured SH-SY5Y cells and prevents the cells from the apoptosis. We concluded that the ZnONPs potentially kills the neuroblastoma cells by producing the intracellular ROS.

Comprehensive In Vitro Testing of Calcium Phosphate-Based Bioceramics with Orthopedic and Dentistry Applications

Recently, a large spectrum of biomaterials emerged, with emphasis on various pure, blended, or doped calcium phosphates (CaPs). Although basic cytocompatibility testing protocols are referred by International Organization for Standardization (ISO) 10993 (parts 1-22), rigorous in vitro testing using cutting-edge technologies should be carried out in order to fully understand the behavior of various biomaterials (whether in bulk or low-dimensional object form) and to better gauge their outcome when implanted. In this review, current molecular techniques are assessed for the in-depth characterization of angiogenic potential, osteogenic capability, and the modulation of oxidative stress and inflammation properties of CaPs and their cation- and/or anion-substituted derivatives. Using such techniques, mechanisms of action of these compounds can be deciphered, highlighting the signaling pathway activation, cross-talk, and modulation by microRNA expression, which in turn can safely pave the road toward a better filtering of the truly functional, application-ready innovative therapeutic bioceramic-based solutions.

Mechanism of Apoptosis Induced by Curcumin in Colorectal Cancer

Colorectal cancer (CRC) is among the top three cancer with higher incident and mortality rate worldwide. It is estimated that about over than 1.1 million of death and 2.2 million new cases by the year 2030. The current treatment modalities with the usage of chemo drugs such as FOLFOX and FOLFIRI, surgery and radiotherapy, which are usually accompanied with major side effects, are rarely cured along with poor survival rate and at higher recurrence outcome. This trigger the needs of exploring new natural compounds with anti-cancer properties which possess fewer side effects. Curcumin, a common spice used in ancient medicine was found to induce apoptosis by targeting various molecules and signaling pathways involved in CRC. Disruption of the homeostatic balance between cell proliferation and apoptosis could be one of the promoting factors in colorectal cancer progression. In this review, we describe the current knowledge of apoptosis regulation by curcumin in CRC with regard to molecular targets and associated signaling pathways.

MRPL35 Is Up-Regulated in Colorectal Cancer and Regulates Colorectal Cancer Cell Growth and Apoptosis

Mitochondrial ribosome proteins (MRPs), which are encoded by the nuclear genomic DNA, are important for mitochondrial-encoded protein synthesis and mitochondrial function. Emerging evidence suggests that several MRPs also exhibit important extra-mitochondrial functions, such as involvement in apoptosis, protein biosynthesis, and signal transduction. In this study, we demonstrate a significant role of MRP L35 (MRPL35) in colorectal cancer (CRC). The expression of MRPL35 was higher in CRC tissues than in matched cancer-adjacent tissues and higher in CRC cells than in normal mucosal epithelial cells. Higher MRPL35 expression in CRC tissue correlated with shorter overall survival for CRC patients. In vitro, down-regulation of MRPL35 led to increased production of reactive oxygen species (ROS) together with DNA damage, loss of cell proliferation, G₂/M arrest, a decrease in mitochondrial membrane potential, apoptosis, and autophagy induction. MRPL35 knockdown inhibited tumor proliferation in a CRC xenograft nude mouse model. Furthermore, overexpression of MRPL35 or treatment of cells with the ROS scavenger, N-acetyl cysteine, abrogated ROS production, cell cycle arrest, and apoptosis in vitro. These findings suggest that MRPL35 plays an essential role in the development of CRC and may be a potential therapeutic target for CRC.

Extracellular Electrophysiology in the Prostate Cancer Cell Model PC-3

Although prostate cancer is one of the most common cancers in the male population, its basic biological function at a cellular level remains to be fully understood. This lack of in depth understanding of its physiology significantly hinders the development of new, targeted and more effective treatment strategies. Whilst electrophysiological studies can provide in depth analysis, the possibility of recording electrical activity in large populations of non-neuronal cells remains a significant challenge, even harder to address in the picoAmpere-range, which is typical of cellular level electrical activities. In this paper, we present the measurement and characterization of electrical activity of populations of prostate cancer cells PC-3, demonstrating for the first time a meaningful electrical pattern. The low noise system used comprises a multi-electrode array (MEA) with circular gold electrodes on silicon oxide substrates. The extracellular capacitive currents present two standard patterns: an asynchronous sporadic pattern and a synchronous quasi-periodic biphasic spike pattern. An amplitude of ±150 pA, a width between 50⁻300 ms and an inter-spike interval around 0.5 Hz characterize the quasi-periodic spikes. Our experiments using treatment of cells with Gd³⁺, known as an inhibitor for the Ca²⁺ exchanges, suggest that the quasi-periodic signals originate from Ca²⁺ channels. After adding the Gd³⁺ to a population of living PC-3 cells, their electrical activity considerably decreased; once the culture was washed, thus eliminating the Gd³⁺ containing medium and addition of fresh cellular growth medium, the PC-3 cells recovered their normal electrical activity. Cellular viability plots have been carried out, demonstrating that the PC-3 cells remain viable after the use of Gd³⁺, on the timescale of this experiment. Hence, this experimental work suggests that Ca²⁺ is significantly affecting the electrophysiological communication pattern among PC-3 cell populations. Our measuring platform opens up new avenues for real time and highly sensitive investigations of prostate cancer signalling pathways.

The Delicate Equilibrium between Oxidants and Antioxidants in Brain Glioma

Gliomas are the most frequent brain tumors in the adult population and unfortunately the adjuvant therapies are not effective. Brain tumorigenesis has been related both to the increased levels of free radicals as inductors of severe damages in healthy cells, but also with the reduced response of endogenous enzyme and non-enzymatic antioxidant defenses. In turn, both processes induce the change to malignant cells. In this review, we analyzed the role of the imbalance between free radicals production and antioxidant mechanism in the development and progression of gliomas but also the influence of redox status on the two major distinctive forms of programmed cell death related to cancer: apoptosis and autophagy. These data may be the reference to the development of new pharmacological options based on redox microenvironment for glioma treatment.

Honey and cancer: A mechanistic review

BACKGROUND

Globally, cancer ranks among the most common causes of death. Multiple experimental and clinical studies have investigated anticancer effects of honey with promising results. This study focused on potential background mechanisms of this effect.

METHODS

The current literature was reviewed for potential anticancer pathways which are suggested for honey and its ingredients.

RESULTS

Flavonoids (kaempferol, catechin, and quercetin) and phenolic acids (caffeic acid and gallic acid) are the most important ingredients of honey with known anti-cancer activity. The main suggested mechanisms for anti-cancer activity of honey and its ingredients are antioxidant, apoptotic, tumor necrosis factor inhibiting, antiproliferative, immunomodulatory, anti-inflammatory and estrogenic effects.

CONCLUSION

This review collates the current scientific understanding on the mechanism of anti-cancer activity of honey.

Effects of a novel peptide Ac-SDKP in radiation-induced coronary endothelial damage and resting myocardial blood flow

Background

Cancer survivors treated with thoracic ionizing radiation are at higher risk of premature death due to myocardial ischemia. No therapy is currently available to prevent or mitigate these effects. We tested the hypothesis that an endogenous tetrapeptide N-acetyl-Ser-Asp-Lys-Pro (Ac-SDKP) counteracts radiation-induced coronary vascular fibrosis and endothelial cell loss and preserves myocardial blood flow.

Methods

We examined a rat model with external-beam-radiation exposure to the cardiac silhouette. We treated a subgroup of irradiated rats with subcutaneous Ac-SDKP for 18-weeks. We performed cardiac MRI with Gadolinium contrast to examine resting myocardial blood flow content. Upon sacrifice, we examined coronary endothelial-cell-density, fibrosis, apoptosis and endothelial tight-junction proteins (TJP). In vitro, we examined Ac-SDKP uptake by the endothelial cells and tested its effects on radiation-induced reactive oxygen species (ROS) generation. In vivo, we injected labeled Ac-SDKP intravenously and examined its endothelial localization after 4-h.

Results

We found that radiation exposure led to reduced resting myocardial blood flow content. There was concomitant endothelial cell loss and coronary fibrosis. Smaller vessels and capillaries showed more severe changes than larger vessels. Real-time PCR and confocal microscopy showed radiation-induced loss of TJ proteins including- claudin-1 and junctional adhesion molecule-2 (JAM-2). Ac-SDKP normalized myocardial blood flow content, inhibited endothelial cell loss, reduced coronary fibrosis and restored TJ-assembly. In vitro, Ac-SDKP localized to endothelial cells and inhibited radiation-induced endothelial ROS generation. In vivo, labeled Ac-SDKP was visualized into the endothelium 4-h after the intravenous injection.

Conclusions

We concluded that Ac-SDKP has protective effects against radiation-induced reduction of myocardial blood flow. Such protective effects are likely mediated by neutralization of ROS-mediated injury, preservation of endothelial integrity and inhibition of fibrosis. This demonstrates a strong therapeutic potential of Ac-SDKP to counteract radiotherapy-induced coronary disease.

Electronic supplementary material

The online version of this article (10.1186/s40959-018-0034-1) contains supplementary material, which is available to authorized users.

Medicinal chemistry of acridine and its analogues

'Acridine' along with its functional analogue 'Acridone' is the most privileged pharmacophore in medicinal chemistry with diverse applications ranging from DNA intercalators, endonuclease mimics, ratiometric selective ion sensors, and P-glycoprotein inhibitors in countering the multi-drug resistance, enzyme inhibitors, and reversals of neurodegenerative disorders. Their interaction with DNA and ability of selectively identifying numerous biologically useful ions has cemented exploitability of the acridone nucleus in modern day therapeutics. Additionally, most derivatives and salts of acridine are planar, crystalline, and stable displaying a strong fluorescence which, when coupled with their marked bio selectivity and low cytotoxicity, enables the studying and monitoring of several biochemical, metabolic, and pharmacological processes. In this review, a detailed picture covering the important therapeutic aspects of the acridone nucleus and its functional analogues is discussed.

Phenolic Compounds in Honey and Their Associated Health Benefits: A Review

Honey is a natural substance appreciated for its therapeutic abilities since ancient times. Its content in flavonoids and phenolic acids plays a key role on human health, thanks to the high antioxidant and anti-inflammatory properties that they exert. Honey possesses antimicrobial capacity and anticancer activity against different types of tumors, acting on different molecular pathways that are involved on cellular proliferation. In addition, an antidiabetic activity has also been highlighted, with the reduction of glucose, fructosamine, and glycosylated hemoglobin serum concentration. Honey exerts also a protective effect in the cardiovascular system, where it mainly prevents the oxidation of low-density lipoproteins, in the nervous system, in the respiratory system against asthma and bacterial infections, and in the gastrointestinal system. A beneficial effect of honey can also be demonstrated in athletes. The purpose of this review is to summarize and update the current information regarding the role of honey in health and diseases.

Bioenergetics of life, disease and death phenomena

In this article, some new aspects of unified cell bioenergetics are presented. From the perspective of unified cell bioenergetics certain subsequent stages of cancer development, from initiation stage, through transformation to metastasis, are analyzed. Here we show that after transformation, cancer cells are permanently exposed to reactive oxygen species, that causes continual random DNA mutations and as a result genome and chromosomal destabilizations. The modern cancer attractor hypothesis has been extended in explaining cancer development. Discussion is conducted in light of current cancerogenesis research, including bioenergetic cancer initiation, the somatic mutation theory and the tissue organization field theory. In the article reasons complicating the discovery of patterns of cancer genome changes and cancer evolution are presented. In addition certain cancer therapeutic aspects are given attention to.

The Role of TRP Channels in the Metastatic Cascade

A dysregulated cellular Ca2+ homeostasis is involved in multiple pathologies including cancer. Changes in Ca2+ signaling caused by altered fluxes through ion channels and transporters (the transportome) are involved in all steps of the metastatic cascade. Cancer cells thereby "re-program" and "misuse" the cellular transportome to regulate proliferation, apoptosis, metabolism, growth factor signaling, migration and invasion. Cancer cells use their transportome to cope with diverse environmental challenges during the metastatic cascade, like hypoxic, acidic and mechanical cues. Hence, ion channels and transporters are key modulators of cancer progression. This review focuses on the role of transient receptor potential (TRP) channels in the metastatic cascade. After briefly introducing the role of the transportome in cancer, we discuss TRP channel functions in cancer cell migration. We highlight the role of TRP channels in sensing and transmitting cues from the tumor microenvironment and discuss their role in cancer cell invasion. We identify open questions concerning the role of TRP channels in circulating tumor cells and in the processes of intra- and extravasation of tumor cells. We emphasize the importance of TRP channels in different steps of cancer metastasis and propose cancer-specific TRP channel blockade as a therapeutic option in cancer treatment.

Liver antioxidant and aerobic status improves after metformin and melatonin administration in a rat model of high-fat diet and mammary carcinogenesis

Oxidative stress is involved in the development of various cancers. In the present study, the effect of long-term administration of peroral antidiabetic metformin and pineal hormone melatonin on liver antioxidant and aerobic status in female Sprague-Dawley rats carrying mammary tumors induced by N-methyl-N-nitrosourea was evaluated. Both substances were administered in a preventive and curative manner (12 days before and 16 weeks after the carcinogen application). Carcinogen administration induced oxidative stress: the level of thiobarbituric acid reactive substances (TBARS) considered as a marker of reactive oxygen species (ROS) generation in liver increased as well as the level of oxidatively modified protein content (OMP; aldehyde and ketone derivates). Metformin administration restored succinate dehydrogenase and lactate dehydrogenase activity and associated ROS production and OMP content to the level of intact rats, with predominant activation of superoxide dismutase (SOD) and glutathione reductase (GR). Melatonin alone and in combination with metformin also decreased TBARS content. OMP content decreased in all groups receiving chemoprevention. The rise in total antioxidant capacity after melatonin and particularly metformin and melatonin combination might result from the initiation of anaerobic metabolism and increasing SOD, GR, and glutathione peroxidase activity. Long-term administration of metformin and melatonin exerts antioxidant properties in liver, especially in combination.

Activation of autophagy by stress-activated signals as a cellular self-defense mechanism against the cytotoxic effects of MBIC in human breast cancer cells in vitro

We recently reported that methyl 2-(-5-fluoro-2-hydroxyphenyl)-1H-benzo[d]imidazole-5-carboxylate (MBIC) is a microtubule targeting agent (MTA) with multiple mechanisms of action including apoptosis in two human breast cancer cell-lines MCF-7 and MDA-MB-231. In the present study, investigation of early molecular events following MBIC treatment demonstrated the induction of autophagy. This early (<24 h) response to MBIC was characterized by accumulation of autophagy markers; LC3-II, Beclin1, autophagic proteins (ATGs) and collection of autophagosomes but with different variations in the two cell-lines. MBIC-induced autophagy was associated with generation of reactive oxygen species (ROS). In parallel, an increased activation of SAPK/JNK pathway was detected, as an intersection of ROS production and induction of autophagy. The cytotoxic effect of MBIC was enhanced by inhibition of autophagy through blockage of SAPK/JNK signaling, suggesting that MBIC-induced autophagy, is a possible cellular self-defense mechanism against toxicity of this agent in both breast cancer cell-lines. The present findings suggest that inhibition of autophagy eliminates the cytoprotective activity of MDA-MB-231 and MCF-7 cells, and sensitizes both the aggressive and non-aggressive human breast cancer cell-lines to the cytotoxic effects of MBIC.

Redox control of cancer cell destruction

Redox regulation has been proposed to control various aspects of carcinogenesis, cancer cell growth, metabolism, migration, invasion, metastasis and cancer vascularization. As cancer has many faces, the role of redox control in different cancers and in the numerous cancer-related processes often point in different directions. In this review, we focus on the redox control mechanisms of tumor cell destruction. The review covers the tumor-intrinsic role of oxidants derived from the reduction of oxygen and nitrogen in the control of tumor cell proliferation as well as the roles of oxidants and antioxidant systems in cancer cell death caused by traditional anticancer weapons (chemotherapeutic agents, radiotherapy, photodynamic therapy). Emphasis is also put on the role of oxidants and redox status in the outcome following interactions between cancer cells, cytotoxic lymphocytes and tumor infiltrating macrophages.

Reactive oxygen species and colorectal cancer

Colorectal cancer (CRC) has become the fourth leading cause of cancer-related death in the worldwide. It is urgent to find more effective therapeutic strategies for it. Reactive oxygen species (ROS) play multiple roles in normal cellular physiology processes. Thus, a certain level of ROS is essential to keep normal cellular function. However, the accumulation of ROS shows dual roles for cells, which is mainly dependent on the concentration of ROS, the origin of the cancer cell and the activated signaling pathways during tumor progression. In general, moderate level of ROS leads to cell damage, DNA mutation and inflammation, which promotes the initiation and development of cancer. Excessive high level of ROS induces cancer cell death, showing an anti-cancer role. ROS are commonly higher in CRC cells than their normal counterpart cells. Therefore, it is possible that ROS induce cell death in cancer cells while not affecting the normal cells, demonstrating lower side effects. Besides, ROS also play a role in tumor microenvironment and drug resistance. These multiple roles of ROS make them a promising therapeutic target for cancer. To explore potential ROS-target therapies against CRC, it is worth to comprehensively understanding the role of ROS in CRC and therapy. In this review, we mainly discuss the strategies of ROS in CRC therapy, including direct CRC cell target and indirect tumor environment target. In addition, the influences of ROS in drug resistance will also been discussed.