Expression of MUC1 mucin in full-term pregnancy human placenta

Low reactivity of tumor MUC1-binding natural anti-α-galactoside antibody is a risk factor for breast cancer

Natural plasma anti-α-galactoside antibody (anti-Gal) reactivity was reported to vary inversely with the individual’s lipoprotein(a) [Lp(a)] size. Since MUC1 mucin over-expressed in tumors bear surrogate peptide ligands for anti-Gal, we examined if high anti-Gal reactivity in small size/high titer Lp(a) individuals correlated with lower incidence of breast cancer. Newer protocol for size determination revealed that Lp(a) in controls were significantly smaller than in breast cancer patients ( P =  0.0023; n = 46 in either group). Activity per unit plasma volume and specific reactivity (reactivity per unit immunoglobulin) of anti-Gal were significantly lower in cancer patients ( P = 0.0033). Specific reactivity lower than the mean of controls was a risk factor for breast cancer with odds ratio (OR) 3.2 (95% confidence interval [CI]: 1.368–7.557). Immunochemical staining using fluorescein isothiocyanate-labeled anti-Gal revealed absolute inactivity towards normal cells and strong recognition of cancer cells by the antibody. O-Glycosylation of MUC1, though more frequent than in normal cells, was incomplete in tumor cells as revealed by binding of the O-glycan-specific lectin jacalin, accounting for the access of anti-Gal to its peptide ligand in cancer MUC1. As tumor advanced and MUC1 with increasing affinity for anti-Gal was synthesized by the tumor, the specific reactivity of circulating anti-Gal also increased, apparently due to antigenic stimulation or affinity maturation by the proliferating MUC1, indicating that pre-cancer anti-Gal reactivity in patients should have been much lower than measured after detection of cancer and that lower reactivity of the antibody is a stronger risk factor for breast cancer than indicated by the OR above. Reactivity towards a given group of tumor MUC1 antigens increased in proportion to anti-Gal specific reactivity. Results suggested tumor-specific MUC1 as likely target for anti-Gal-mediated anti-cancer defense and offer infusion of small Lp(a) or high reactivity anti-Gal as possible immunopotentiation measures.

Impact statement

This paper offers a molecular explanation for the positive correlation of individuals’ lipoprotein(a) [Lp(a)] size with breast cancer incidence, found more pronounced using interference-free assays. It established unambiguously the marked affinity of human anti-Gal antibody towards cancer phenotype of the cell surface MUC1 and inertness towards normal cell MUC1. This selectivity enabled small Lp(a) molecules, known to produce higher specific reactivity anti-Gal by affinity maturation, to achieve more efficient immune defense so that women with specific reactivity lower than the mean value of normal subjects ran cancer risk with odds ratio (OR) above 3.2. However, increasing O-glycosylation and decreasing O-glycan length of MUC1 with tumor advance increased anti-Gal specific reactivity, indicating antigenic stimulation and/or affinity maturation of the antibody by tumor MUC1. Thus, pre-cancer anti-Gal specific reactivity should be lower than that measured on detection and the above OR actually higher. Results suggest small Lp(a) and high specific reactivity anti-Gal infusions as therapeutic options.

Interaction of extravillous trophoblast galectin-1 and mucin(s)-Is there a functional relevance?

In the course of embryo implantation extensive interaction of the trophoblast with uterine tissue is crucial for adequate trophoblast invasion. This interaction is highly controlled, and it has been pointed out that a specific glycocode and changes in glycosylation may be important for successful implantation and maintenance of pregnancy. Both uterine and trophoblast cells have been shown to express cell surface glycoconjugates and sugar binding proteins, such as mucins (MUC) and galectins (gals). An increasing number of studies have investigated potential candidates interacting in this process. However, knowledge about the biochemical nature of the interactions and their importance for trophoblast cell function, and, consequently, for pregnancy outcome are still lacking. This review is aimed at deliberating the possibility that mucins, as heavily glycosylated proteins, might be among the functionally relevant galectin ligands in human trophoblast, based on both published data and our original research.

Surprising prenatal toxicity of epidermal lipoxygenase-3

Metabolites of the epidermal lipoxygenase-3 (eLOX-3) are involved in various metabolic pathways. Most unexpectedly, intra-amniotic delivery of eLOX-3 to mice at gestational day 14.5, both via an adenoviral vector and as recombinant protein, resulted in fetal growth restriction and intrauterine death. Periodic acid-Schiff staining and RT-PCR analysis of placentae from fetuses exposed to eLOX-3 indicated a lack of glycogen trophoblasts in the junctional zone. Placenta-specific gene expression was altered. Thus, the observed prenatal toxicity of eLOX-3 could be due to a strong effect on placental development.

Altered global gene expressions of human placentae subjected to assisted reproductive technology treatments

BACKGROUND

Researchers are more and more concerning the safety of fetus or offspring derived from assisted reproductive technology (ART) treatment. As the placenta is a critical organ that sustains and protects the fetus, we hypothesize that altered global gene expression of the placenta subjected to ART manipulation may reflect changes associated with ART procedures and subsequently causal related to offspring health.

METHODS

Three term placenta samples were obtained from patients undergone in vitro fertilization and embryo transfer due to oviductal factors only. Other three control placentae were from those underwent normal pregnancy. A GeneChip Affymetrix HG-U133 Plus 2.0 Array was utilized to analyze the genes. Using qRT-PCR we certified microarray data from 10 dysregulated genes. Five genes were localized precisely in the placenta as per immunohistochemistry.

RESULTS

Twenty-six differentially expressed genes were identified in the ART-treated placentae: 17 up-regulated; 9 down-regulated. Eighteen of these were classified into six groups according to critical placental function: immune response; transmembrane transport; metabolism; oxidative stress; cell differentiation; and other functions. Genes involved in immune response, such as ERAP2 and STAT4, and those regulating cell differentiations, such as MUC1, were discerned to be differentially expressed. These gene products were expressed in the placental villus tissues, either in the cytoplasm or in the membrane of syncytiotrophoblastic cells.

CONCLUSION

To our knowledge, this is the first study in comparing differentially expressed genes in placentae from patients undergone ART treatment vs. those underwent normal pregnancy. Abnormal profiles of critical placental functioning genes, such as ERAP2, STAT4 and MUC1, may be valuable biomarkers to understand how the placenta affects fetal development and ART-derived offspring's health problems.