High-Throughput Mass Spectrometry Analysis of N-Glycans and Protein Markers after FUT8 Knockdown in the Syngeneic SW480/SW620 Colorectal Cancer Cell Model.

Disruption of the glycosylation machinery is a common feature in many types of cancer, and colorectal cancer (CRC) is no exception. Core fucosylation is mediated by the enzyme fucosyltransferase 8 (FucT-8), which catalyzes the addition of α1,6-l-fucose to the innermost GlcNAc residue of N-glycans. We and others have documented the involvement of FucT-8 and core-fucosylated proteins in CRC progression, in which we addressed core fucosylation in the syngeneic CRC model formed by SW480 and SW620 tumor cell lines from the perspective of alterations in their N-glycosylation profile and protein expression as an effect of the knockdown of the FUT8 gene that encodes FucT-8. Using label-free, semiquantitative mass spectrometry (MS) analysis, we found noticeable differences in N-glycosylation patterns in FUT8-knockdown cells, affecting core fucosylation and sialylation, the Hex/HexNAc ratio, and antennarity. Furthermore, stable isotopic labeling of amino acids in cell culture (SILAC)-based proteomic screening detected the alteration of species involved in protein folding, endoplasmic reticulum (ER) and Golgi post-translational stabilization, epithelial polarity, and cellular response to damage and therapy. This data is available via ProteomeXchange with identifier PXD050012. Overall, the results obtained merit further investigation to validate their feasibility as biomarkers of progression and malignization in CRC, as well as their potential usefulness in clinical practice.

Core Fucosylation Mediated by the FucT-8 Enzyme Affects TRAIL-Induced Apoptosis and Sensitivity to Chemotherapy in Human SW480 and SW620 Colorectal Cancer Cells.

Epithelial cells can undergo apoptosis by manipulating the balance between pro-survival and apoptotic signals. In this work, we show that TRAIL-induced apoptosis can be differentially regulated by the expression of α(1,6)fucosyltransferase (FucT-8), the only enzyme in mammals that transfers the α(1,6)fucose residue to the pentasaccharide core of complex N-glycans. Specifically, in the cellular model of colorectal cancer (CRC) progression formed using the human syngeneic lines SW480 and SW620, knockdown of the FucT-8-encoding FUT8 gene significantly enhanced TRAIL-induced apoptosis in SW480 cells. However, FUT8 repression did not affect SW620 cells, which suggests that core fucosylation differentiates TRAIL-sensitive premetastatic SW480 cells from TRAIL-resistant metastatic SW620 cells. In this regard, we provide evidence that phosphorylation of ERK1/2 kinases can dynamically regulate TRAIL-dependent apoptosis and that core fucosylation can control the ERK/MAPK pro-survival pathway in which SW480 and SW620 cells participate. Moreover, the depletion of core fucosylation sensitises primary tumour SW480 cells to the combination of TRAIL and low doses of 5-FU, oxaliplatin, irinotecan, or mitomycin C. In contrast, a combination of TRAIL and oxaliplatin, irinotecan, or bevacizumab reinforces resistance of FUT8-knockdown metastatic SW620 cells to apoptosis. Consequently, FucT-8 could be a plausible target for increasing apoptosis and drug response in early CRC.

Therapeutic Potential of Melatonin Counteracting Chemotherapy-Induced Toxicity in Breast Cancer Patients: A Systematic Review.

The purpose of this systematic review is to provide an overview of the existing knowledge on the therapeutic potential of melatonin to counteract the undesirable effects of chemotherapy in breast cancer patients. To this aim, we summarized and critically reviewed preclinical- and clinical-related evidence according to the PRISMA guidelines. Additionally, we developed an extrapolation of melatonin doses in animal studies to the human equivalent doses (HEDs) for randomized clinical trials (RCTs) with breast cancer patients. For the revision, 341 primary records were screened, which were reduced to 8 selected RCTs that met the inclusion criteria. We assembled the evidence drawn from these studies by analyzing the remaining gaps and treatment efficacy and suggested future translational research and clinical trials. Overall, the selected RCTs allow us to conclude that melatonin combined with standard chemotherapy lines would derive, at least, a better quality of life for breast cancer patients. Moreover, regular doses of 20 mg/day seemed to increase partial response and 1-year survival rates. Accordingly, this systematic review leads us to draw attention to the need for more RCTs to provide a comprehensive view of the promising actions of melatonin in breast cancer and, given the safety profile of this molecule, adequate translational doses should be established in further RCTs.

Melatonin as Modulator for Sulfur and Nitrogen Mustard-Induced Inflammation, Oxidative Stress and DNA Damage: Molecular Therapeutics.

Sulfur and nitrogen mustards, bis(2-chloroethyl)sulfide and tertiary bis(2-chloroethyl) amines, respectively, are vesicant warfare agents with alkylating activity. Moreover, oxidative/nitrosative stress, inflammatory response induction, metalloproteinases activation, DNA damage or calcium disruption are some of the toxicological mechanisms of sulfur and nitrogen mustard-induced injury that affects the cell integrity and function. In this review, we not only propose melatonin as a therapeutic option in order to counteract and modulate several pathways involved in physiopathological mechanisms activated after exposure to mustards, but also for the first time, we predict whether metabolites of melatonin, cyclic-3-hydroxymelatonin, N1-acetyl-N2-formyl-5-methoxykynuramine, and N1-acetyl-5-methoxykynuramine could be capable of exerting a scavenger action and neutralize the toxic damage induced by these blister agents. NLRP3 inflammasome is activated in response to a wide variety of infectious stimuli or cellular stressors, however, although the precise mechanisms leading to activation are not known, mustards are postulated as activators. In this regard, melatonin, through its anti-inflammatory action and NLRP3 inflammasome modulation could exert a protective effect in the pathophysiology and management of sulfur and nitrogen mustard-induced injury. The ability of melatonin to attenuate sulfur and nitrogen mustard-induced toxicity and its high safety profile make melatonin a suitable molecule to be a part of medical countermeasures against blister agents poisoning in the near future.

Potential of melatonin to reverse epigenetic aberrations in oral cancer: new findings.

It is now an accepted principle that epigenetic alterations cause cellular dyshomeostasis and functional changes, both of which are essential for the initiation and completion of the tumor cycle. Oral carcinogenesis is no exception in this regard, as most of the tumors in the different subsites of the oral cavity arise from the cross-reaction between (epi)genetic inheritance and the huge challenge of environmental stressors. Currently, the biochemical machinery is put at the service of the tumor program, halting the cell cycle, triggering uncontrolled proliferation, driving angiogenesis and resistance to apoptosis, until the archetypes of the tumor phenotype are reached. Melatonin has the ability to dynamically affect the epigenetic code. It has become accepted that melatonin can reverse (epi)genetic aberrations present in oral and other cancers, suggesting the possibility of enhancing the oncostatic capacity of standard multimodal treatments by incorporating this indolamine as an adjuvant. First steps in this direction confirm the potential of melatonin as a countermeasure to mitigate the detrimental side effects of conventional first-line radiochemotherapy. This single effect could produce synergies of extraordinary clinical importance, allowing doses to be increased and treatments not to be interrupted, ultimately improving patients' quality of life and prognosis. Motivated by the urgency of improving the medical management of oral cancer, many authors advocate moving from in vitro and preclinical research, where the bulk of melatonin cancer research is concentrated, to systematic randomized clinical trials on large cohorts. Recognizing the challenge to improve the clinical management of cancer, our motivation is to encourage comprehensive and robust research to reveal the clinical potential of melatonin in oral cancer control. To improve the outcome and quality of life of patients with oral cancer, here we provide the latest evidence of the oncolytic activity that melatonin can achieve by manipulating epigenetic patterns in oronasopharyngeal tissue.

Inhibition of α(1,6)fucosyltransferase: Effects on Cell Proliferation, Migration, and Adhesion in an SW480/SW620 Syngeneic Colorectal Cancer Model.

The present study explored the impact of inhibiting α(1,6)fucosylation (core fucosylation) on the functional phenotype of a cellular model of colorectal cancer (CRC) malignization formed by the syngeneic SW480 and SW620 CRC lines. Expression of the FUT8 gene encoding α(1,6)fucosyltransferase was inhibited in tumor line SW480 by a combination of shRNA-based antisense knockdown and Lens culinaris agglutinin (LCA) selection. LCA-resistant clones were subsequently assayed in vitro for proliferation, migration, and adhesion. The α(1,6)FT-inhibited SW480 cells showed enhanced proliferation in adherent conditions, unlike their α(1,6)FT-depleted SW620 counterparts, which displayed reduced proliferation. Under non-adherent conditions, α(1,6)FT-inhibited SW480 cells also showed greater growth capacity than their respective non-targeted control (NTC) cells. However, cell migration decreased in SW480 after FUT8 knockdown, while adhesion to EA.hy926 cells was significantly enhanced. The reported results indicate that the FUT8 knockdown strategy with subsequent selection for LCA-resistant clones was effective in greatly reducing α(1,6)FT expression in SW480 and SW620 CRC lines. In addition, α(1,6)FT impairment affected the proliferation, migration, and adhesion of α(1,6)FT-deficient clones SW480 and SW620 in a tumor stage-dependent manner, suggesting that core fucosylation has a dynamic role in the evolution of CRC.

Influence of the extraction method on the recovery of bioactive phenolic compounds from food industry by-products.

Agro-foodindustries generate colossal amounts of non-edible waste and by-products, easily accessible as raw materials for up-cycling active phytochemicals. Phenolic compounds are particularly relevant in this field given their abundance in plant residues and the market interest of their functionalities (e.g. natural antioxidant activity) as part of nutraceutical, cosmetological and biomedical formulations. In "bench-to-bedside" achievements, sample extraction is essential because valorization benefits from matrix desorption and solubilization of targeted phytocompounds. Specifically, the composition and polarity of the extractant, the optimal sample particle size and sample:solvent ratio, as well as pH, pressure and temperature are strategic for the release and stability of mobilized species. On the other hand, current green chemistry environmental rules require extraction approaches that eliminate polluting consumables and reduce energy needs. Thus, the following pages provide an update on advanced technologies for the sustainable and efficient recovery of phenolics from plant matrices.

Coronavirus Disease 2019 (COVID-19) and Its Neuroinvasive Capacity: Is It Time for Melatonin?

The world faces an exceptional new public health concern caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), subsequently termed the coronavirus disease 2019 (COVID-19) by the World Health Organization (WHO). Although the clinical symptoms mostly have been characterized, the scientific community still doesn´t know how SARS-CoV-2 successfully reaches and spreads throughout the central nervous system (CNS) inducing brain damage. The recent detection of SARS-CoV-2 in the cerebrospinal fluid (CSF) and in frontal lobe sections from postmortem examination has confirmed the presence of the virus in neural tissue. This finding reveals a new direction in the search for a neurotherapeutic strategy in the COVID-19 patients with underlying diseases. Here, we discuss the COVID-19 outbreak in a neuroinvasiveness context and suggest the therapeutic use of high doses of melatonin, which may favorably modulate the immune response and neuroinflammation caused by SARS-CoV-2. However, clinical trials elucidating the efficacy of melatonin in the prevention and clinical management in the COVID-19 patients should be actively encouraged.

The Coronavirus Disease 2019 (COVID-19): Key Emphasis on Melatonin Safety and Therapeutic Efficacy.

Viral infections constitute a tectonic convulsion in the normophysiology of the hosts. The current coronavirus disease 2019 (COVID-19) pandemic is not an exception, and therefore the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, like any other invading microbe, enacts a generalized immune response once the virus contacts the body. Melatonin is a systemic dealer that does not overlook any homeostasis disturbance, which consequently brings into play its cooperative triad, antioxidant, anti-inflammatory, and immune-stimulant backbone, to stop the infective cycle of SARS-CoV-2 or any other endogenous or exogenous threat. In COVID-19, the corporal propagation of SARS-CoV-2 involves an exacerbated oxidative activity and therefore the overproduction of great amounts of reactive oxygen and nitrogen species (RONS). The endorsement of melatonin as a possible protective agent against the current pandemic is indirectly supported by its widely demonstrated beneficial role in preclinical and clinical studies of other respiratory diseases. In addition, focusing the therapeutic action on strengthening the host protection responses in critical phases of the infective cycle makes it likely that multi-tasking melatonin will provide multi-protection, maintaining its efficacy against the virus variants that are already emerging and will emerge as long as SARS-CoV-2 continues to circulate among us.

Toxicology of Blister Agents: Is Melatonin a Potential Therapeutic Option?

Blister or vesicant chemical warfare agents (CWAs) have been widely used in different military conflicts, including World War I and the Iran-Iraq War. However, their mechanism of action is not fully understood. Sulfur and nitrogen mustard exert toxic effects not only through the alkylation of thiol-bearing macromolecules, such as DNA and proteins, but also produce free radicals that can develop direct toxic effects in target organs such as the eyes, skin, and respiratory system. The lack of effective treatments against vesicant CWAs-induced injury makes us consider, in this complex scenario, the use and development of melatonin-based therapeutic strategies. This multifunctional indoleamine could facilitate neutralization of the oxidative stress, modulate the inflammatory response, and prevent the DNA damage, as well as the long-term health consequences mediated by vesicant CWAs-induced epigenetic mechanisms. In this context, it would be essential to develop new galenic formulations for the use of orally and/or topically applied melatonin for the prophylaxis against vesicant CWAs, as well as the development of post-exposure treatments in the near future.

Potential of Melatonin as Adjuvant Therapy of Oral Cancer in the Era of Epigenomics.

The wide variety of epigenetic controls available is rapidly expanding the knowledge of molecular biology even overflowing it. At the same time, it can illuminate unsuspected ways of understanding the etiology of cancer. New emerging therapeutic horizons, then, promise to overcome the current antitumor strategies need. The translational utility of this complexity is particularly welcome in oral cancer (OC), in which natural history is alarmingly disappointing due to the invasive and mutilating surgery, the high relapsing rate, the poor quality of life and the reduced survival after diagnosis. Melatonin activates protective receptor-dependent and receptor-independent processes that prevent tissue cancerisation and inhibit progressive tumor malignancy and metastasis. Related evidence has shown that melatonin pleiotropy encompasses gene expression regulation through all the three best-characterized epigenetic mechanisms: DNA methylation, chromatin modification, and non-coding RNA. OC has received less attention than other cancers despite prognosis is usually negative and there are no significant therapy improvements recorded in the past decade. However, a large research effort is being carried out to elucidate how melatonin´s machinery can prevent epigenetic insults that lead to cancer. In the light of recent findings, a comprehensive examination of biochemistry through which melatonin may reverse epigenetic aberrations in OC is an extraordinary opportunity to take a step forward in the clinical management of patients.

The emergence of melatonin in oncology: Focus on colorectal cancer.

Within the last few decades, melatonin has increasingly emerged in clinical oncology as a naturally occurring bioactive molecule with substantial anticancer properties and a pharmacological profile optimal for joining the currently available pharmacopeia. In addition, extensive experimental data shows that this chronobiotic agent exerts oncostatic effects throughout all stages of tumor growth, from initial cell transformation to mitigation of malignant progression and metastasis; additionally, melatonin alleviates the side effects and improves the welfare of radio/chemotherapy-treated patients. Thus, the support of clinicians and oncologists for the use of melatonin in both the treatment and proactive prevention of cancer is gaining strength. Because of its epidemiological importance and symptomatic debut in advanced stages of difficult clinical management, colorectal cancer (CRC) is a preferential target for testing new therapies. In this regard, the development of effective forms of clinical intervention for the improvement of CRC outcome, specifically metastatic CRC, is urgent. At the same time, the need to reduce the costs of conventional anti-CRC therapy results is also imperative. In light of this status quo, the therapeutic potential of melatonin, and the direct and indirect critical processes of CRC malignancy it modulates, have aroused much interest. To illuminate the imminent future on CRC research, we focused our attention on the molecular mechanisms underlying the multiple oncostatic actions displayed by melatonin in the onset and evolution of CRC and summarized epidemiological evidence, as well as in vitro, in vivo and clinical findings that support the broadly protective potential demonstrated by melatonin.

Haptoglobin expression in human colorectal cancer.

Aims and experimental design. The acute-phase protein haptoglobin (Hp) has been recently detected in colorectal cancer (CRC) tissue, where its expression correlates with metastasis. Recently, we identified Hp as a CDw75 antigen-expressing protein in colorectal tissue. To deepen the knowledge of this protein in CRC, we studied the expression of Hp in healthy and tumour tissue specimens from 62 CRC patients by immunohistochemistry and Western blotting, as well as in the Caco-2 and HT-29 CRC cell lines by quantitative PCR, immunofluorescence microscopy and flow cytometry. Results and discussion. Hp immuno-positive staining was absent in the 18 healthy colorectal specimens analysed, whereas it was observed in 24% (15/62) of the tumour specimens as cytoplasmic granules within cancer cells. Furthermore, Hp expression in CRC was associated with Dukes' stage and the presence of metastasis in our population of study. In vitro cultured Caco-2 and HT-29 cells expressed mRNA for Hp and the protein was detected at the cell surface. Conclusions. This study confirms the expression of Hp in CRC, both in vivo and in vitro, and provides further evidence of its association with disease progression and metastasis.

Melatonin: A hypothesis for Kawasaki disease treatment.

Kawasaki disease (KD) is the most common cause of acquired heart disease with unknown etiology among children in developed countries. Acute inflammation of the vasculature, genetic susceptibility and immunopathogenesis based on a transmittable and infectious origin, are the pathologic events involved in the early inflammatory etiology and progression of this disease. However, the exact causes of KD remain unknown. Current proposed recommendations include three therapy lines; firstly, an initial standard therapy with intravenous immunoglobulin (IVIG) followed by aspirin. Secondly, in cases of high risk of coronary lesions, the adjunctive therapy with corticosteroid is commonly considered. Thirdly, in KD patients refractory to the previous therapies, tumor necrosis factor (TNF-α) antagonists are being used to modulate pro-inflammatory cytokines. In view of this status quo, our starting hypothesis is that the ubiquitous and non-toxic neurohormone melatonin could be of critical importance in developing novel adjuvant therapies against KD, as it occurs with a plethora of other diseases. Considering its pleiotropic properties, particularly its antiinflammatory and immunoregulatory capacities, melatonin should be of great therapeutic interest for helping to control the main pathologic features of KD patients. In addition, this multifunctional indole has a safe pharmacological profile, enhancing the therapeutic activity of several drugs and reducing their possible side effects. Consequently, melatonins actions to manage KD need to be tested in further clinical studies.

Identification of proteins with the CDw75 epitope in human colorectal cancer.

The CDw75 epitope is an α(2,6) sialylated antigen overexpressed in colorectal cancer (CRC), where its expression correlates with the progression of the disease. The CDw75 epitope is located mainly in N-glycoproteins, whose identity remains unknown. The aim of the present study was to identify proteins with the CDw75 epitope as a strategy to deepen the understanding of molecular pathogenesis of CRC and to identify novel biomarkers for this disease. For this purpose, a two-dimensional electrophoresis approach was employed. Protein spots in the gels were matched to the corresponding CDw75 positive spots in the immunoblotted polyvinylidene difluoride membranes, and further identification of the protein species was performed by mass spectrometry. Additionally, one-dimensional western blotting experiments were performed to verify the expression of these candidate proteins in the colorectal tissue and their coincidence in molecular mass with the CDw75-positive bands. The findings of the present study indicate that haptoglobin and the keratins 8 (K8) and 18 (K18) are proteins with the CDw75 epitope in the colorectal tissue from CRC patients and also suggest novel functions and cellular locations for these proteins in the colorectal tissue and in relation to CRC.

Ischemic brain injury: New insights on the protective role of melatonin.

Stroke represents one of the most common causes of brain's vulnerability for many millions of people worldwide. The plethora of physiopathological events associated with brain ischemia are regulate through multiple signaling pathways leading to the activation of oxidative stress process, Ca2+ dyshomeostasis, mitochondrial dysfunction, proinflammatory mediators, excitotoxicity and/or programmed neuronal cell death. Understanding this cascade of molecular events is mandatory in order to develop new therapeutic strategies for stroke. In this review article, we have highlighted the pleiotropic effects of melatonin to counteract the multiple processes of the ischemic cascade. Additionally, experimental evidence supports its actions to ameliorate ischemic long-term behavioural and neuronal deficits, preserving the functional integrity of the blood-brain barrier, inducing neurogenesis and cell proliferation through receptor-dependent mechanism, as well as improving synaptic transmission. Consequently, the synthesis of melatonin derivatives designed as new multitarget-directed products has focused a great interest in this area. This latter has been reinforced by the low cost of melatonin and its reduced toxicity. Furthermore, its spectrum of usages seems to be wide and with the potential for improving human health. Nevertheless, the molecular and cellular mechanisms underlying melatonin´s actions need to be further exploration and accordingly, new clinical studies should be conducted in human patients with ischemic brain pathologies.

Screening of enzymatic synthesis and expression of Lewis determinants in human colorectal carcinoma.

BACKGROUND: Although colorectal carcinogenesis has been intensively studied, the published investigations do not provide a consistent description of how different carbohydrate determinants of colorectal epithelium are modified in colorectal cancer (CRC). OBJECTIVE: This study is an attempt to characterize the terminal fucosylation steps responsible for the synthesis of mono- Le(a)/Le(x)- and difucosylated -Le(b)/Le(y)- Lewis antigens in healthy and tumour CRC tissue. METHODS: An immunohistochemical study of Lewis antigens' expression was undertaken, along with screening of the fucosyltransferase (FT) activities involved in their synthesis, on healthy and tumour samples from 18 patients undergoing CRC. RESULTS: Analysis of alpha(1,2/3/4)FT activities involved in the sequential fucosylation of cores 1 and 2 showed significant increases in tumour tissue. Expressed as microU/mg and control vs. tumour activity (pfrom Wilcoxon's test), the FT activities for Le(a)/Le(b) synthesis were: lacto-N-biose alpha(1,2)/alpha(1,4)FT, 65.4 ± 19.0 vs. 186 ± 35.1 (p< 0.005); lacto-N-fucopentaose 1 alpha(1,4)FT, 64.9 ± 11.9 vs. 125.4 ± 20.7 (p< 0.005); Le(a) alpha(1,2)FT, 56.2 ± 7.2 vs. 130.5 ± 15.6 (p< 0.001). Similarly, for Le(x)/Le(y) synthesis were: N-acetyllactosamine alpha(1,2)-/alpha(1,3)FT, 53.4 ± 12.2 vs. 108.1 ± 18.9 (p< 0.001); 2'-Fucosyl-N-acetyllactosamine alpha(1,3)FT, 61.3 ± 10.7 vs. 126.4 ± 22.9 (p< 0.001); 2'-Fucosyllactose alpha(1,3)FT, 38.9 ± 10.9 vs. 143.6 ± 28.9 (p< 0.001); 2'-Methyllactose alpha(1,3)FT, 30.9 ± 4.8 vs. 66.1 ± 8.1 (p< 0.005); and Le(x) alpha(1,2)FT, 54.3 ± 11.9 vs. 88.2 ± 14.4 (p< 0.001). Immunohistochemical Le(y) expression was increased (p< 0.01 according to Wilcoxon's test) in tumour tissue, with 84.6% of specimens being positive: 7.7% weak, 15.4% moderate and 61.5% high intensity. CONCLUSIONS: Results suggest the activation of the biosynthesis pathways of mono- and difucosylated Lewis histo-blood antigens in tumour tissue from CRC patients, leading to the overexpression of Le(y), probably at the expense of Le(x).

Screening of enzymatic synthesis and expression of Lewis determinants in human colorectal carcinoma

BACKGROUND: Although colorectal carcinogenesis has been intensively studied, the published investigations do not provide a consistent description of how different carbohydrate determinants of colorectal epithelium are modified in colorectal cancer (CRC). OBJECTIVE: This study is an attempt to characterize the terminal fucosylation steps responsible for the synthesis of mono- (Lea/Lex) and difucosylated (Leb/Ley) Lewis antigens in healthy and tumour CRC tissue. METHODS: An immunohistochemical study of Lewis antigens' expression was undertaken, along with screening of the fucosyltransferase (FT) activities involved in their synthesis, on healthy and tumour samples from 18 patients undergoing CRC. RESULTS: Analysis of a(1,2/3/4)FT activities involved in the sequential fucosylation of cores 1 and 2 showed significant increases in tumour tissue. Expressed as mU/mg and control vs. tumour activity (p from Wilcoxon's test), the FT activities for Lea/ Leb synthesis were: lacto-N-biose a(1,2)/a(1,4)FT, 65.4 ± 19.0 vs. 186 ± 35.1 (p < 0.005); lacto-N-fucopentaose 1 a(1,4)FT, 64.9 ± 11.9 vs. 125.4 ± 20.7 (p < 0.005); Lea a(1,2)FT, 56.2 ± 7.2 vs. 130.5 ± 15.6 (p < 0.001). Similarly, for Lex/Ley synthesis were: N-acetyllactosamine a(1,2)-/a(1,3)FT, 53.4 ± 12.2 vs. 108.1 ± 18.9 (p < 0.001); 2'-Fucosyl-N-acetyllactosamine a(1,3)FT, 61.3 ± 10.7 vs. 126.4 ± 22.9 (p < 0.001); 2'-Fucosyllactose a(1,3)FT, 38.9 ± 10.9 vs. 143.6 ± 28.9 (p < 0.001); 2'-Methyllactose a(1,3) FT, 30.9 ± 4.8 vs. 66.1 ± 8.1 (p < 0.005); and Lex a(1,2)FT, 54.3 ± 11.9 vs. 88.2 ± 14.4 (p < 0.001). Immunohistochemical Ley expression was increased (p < 0.01 according to Wilcoxon's test) in tumour tissue, with 84.6% of specimens being positive: 7.7% weak, 15.4% moderate and 61.5% high intensity. CONCLUSIONS: Results suggest the activation of the biosynthesis pathways of mono- and difucosylated Lewis histo-blood antigens in tumour tissue from CRC patients, leading to the overexpression of Ley, probably at the expense of Lex

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FX enzyme and GDP-L-Fuc transporter expression in colorectal cancer.

AIMS: Fucosylation is regulated by fucosyltransferases, the guanosine diphosphate-L-fucose (GDP-L-Fuc) synthetic pathway, and the GDP-L-fucose transporter (GDP-L-Fuc Tr). We have reported previously an increased level of α(1,6)fucosyltransferase activity and expression in colorectal cancer (CRC). The present study aimed to analyse the expression profiles of the FX enzyme and GDP-L-Fuc Tr in a cohort of operated CRC patients to elucidate their role in α(1,6)fucosylation in this neoplasm. METHODS AND RESULTS: We assessed the immunohistochemical expression of FX and GDP-L-Fuc Tr in a series of tumour samples and healthy tissues from CRC specimens. FX expression was observed in 58 of 91 (63.7%) tumours and 23 of 28 (82.1%) corresponding healthy samples. GDP-L-Fuc Tr expression was detected in 86 of 102 (84.3%) colorectal tumours, and 13 of 27 (48.1%) healthy tissue specimens. The expression of GDP-L-Fuc Tr was statistically higher in tumours than in healthy tissues (P < 0.001). A correlation was found between FX and GDP-L-Fuc Tr expression in tumour samples (P = 0.003). CONCLUSION: GDP-L-Fuc Tr overexpression in the tumour tissue of CRC patients suggests that GDP-L-Fuc transport to the Golgi apparatus may be an important factor associated with increased α(1,6)fucosylation in CRC.