Ten millennia of hepatitis B virus evolution

[Figure: see text].

Cancer cell death induced by nanomagnetolectin

Magnetic nanoparticles represent a new paradigm for molecular targeting therapy in cancer. However, the transformative targeting potential of magnetic nanoparticles has been stymied by a key obstacle-safe delivery to specified target cells in vivo. As cancer cells grow under nutrient deprivation and hypoxic conditions and decorate cell surface with excessive sialoglycans, sialic acid binding lectins might be suitable for targeting cancer cells in vivo. Here we explore the potential of magnetic nanoparticles functionalized with wheat germ lectin (WGA) conjugate, so-called nanomagnetolectin, as apoptotic targetable agents for prostate cancer. In the presence of magnetic field (magnetofection) for 15min, 2.46nM nanomagnetolectin significantly promoted apoptosis (∼12-fold, p value <0.01) of prostate cancer cells (LNCaP, PC-3, DU-145) compared to normal prostate epithelial cells (PrEC, PNT2, PZ-HPV-7), when supplemented with 10mM sialic acid under nutrient deprived condition. Nanomagnetolectin targets cell-surface glycosylation, particularly sialic acid as nanomagnetolectin induced apoptosis of cancer cells largely diminished (only 2 to 2.5-fold) compared to normal cells. The efficacy of magnetofected nanomagnetolectin was demonstrated in orthotopically xenografted (DU-145) mice, where tumor was not only completely arrested, but also reduced significantly (p value <0.001). This was further corroborated in subcutaneous xenograft model, where nanomagnetolectin in the presence of magnetic field and photothermal heating at ∼42°C induced apoptosis of tumor by ∼4-fold compared to tumor section heated at ∼42°C, but without magnetic field. Taken all together, the study demonstrates, for the first time, the utility of nanomagnetolectin as a potential cancer therapeutic.

Lectin staining and Western blot data showing differential sialylation of nutrient-deprived cancer cells to sialic acid supplementation

This report provides data that are specifically related to the differential sialylation of nutrient deprived breast cancer cells to sialic acid supplementation in support of the research article entitled, “Nutrient-deprived cancer cells preferentially use sialic acid to maintain cell surface glycosylation" [1]. Particularly, breast cancer cells, when supplemented with sialic acid under nutrient deprivation, display sialylated glycans at the cell surface, but non-malignant mammary cells show sialylated glycans intracellularly. The impact of sialic acid supplementation under nutrient deprivation was demonstrated by measuring levels of expression and sialylation of two markers, EGFR1 and MUC1. This Data in Brief article complements the main manuscript by providing detailed instructions and representative results for cell-level imaging and Western blot analyses of changes in sialylation during nutrient deprivation and sialic acid supplementation. These methods can be readily generalized for the study of many types of glycosylation and various glycoprotein markers through the appropriate selection of fluorescently-labeled lectins.

Nutrient-deprived cancer cells preferentially use sialic acid to maintain cell surface glycosylation

Cancer is characterized by abnormal energy metabolism shaped by nutrient deprivation that malignant cells experience during various stages of tumor development. This study investigated the response of nutrient-deprived cancer cells and their non-malignant counterparts to sialic acid supplementation and found that cells utilize negligible amounts of this sugar for energy. Instead cells use sialic acid to maintain cell surface glycosylation through complementary mechanisms. First, levels of key metabolites (e.g., UDP-GlcNAc and CMP-Neu5Ac) required for glycan biosynthesis are maintained or enhanced upon Neu5Ac supplementation. In concert, sialyltransferase expression increased at both the mRNA and protein levels, which facilitated increased sialylation in biochemical assays that measure sialyltransferase activity as well as at the whole cell level. In the course of these experiments, several important differences emerged that differentiated the cancer cells from their normal counterparts including resistant to sialic acid-mediated energy depletion, consistently more robust sialic acid-mediated glycan display, and distinctive cell surface vs. internal vesicle display of newly-produced sialoglycans. Finally, the impact of sialic acid supplementation on specific markers implicated in cancer progression was demonstrated by measuring levels of expression and sialylation of EGFR1 and MUC1 as well as the corresponding function of sialic acid-supplemented cells in migration assays. These findings both provide fundamental insight into the biological basis of sialic acid supplementation of nutrient-deprived cancer cells and open the door to the development of diagnostic and prognostic tools.

Lectin approaches for glycoproteomics in FDA-approved cancer biomarkers

The nine FDA-approved protein biomarkers for the diagnosis and management of cancer are approaching maturity, but their different glycosylation compositions relevant to early diagnosis still remain practically unexplored at the sub-glycoproteome scale. Lectins generally exhibit strong binding to specific sub-glycoproteome components and this property has been quite poorly addressed as the basis for the early diagnosis methods. Here, we discuss some glycoproteome issues that make tackling the glycoproteome particularly challenging in the cancer biomarkers field and include a brief view for next generation technologies.

Preferential lectin binding of cancer cells upon sialic acid treatment under nutrient deprivation

The terminal monosaccharide of glycoconjugates on a eukaryotic cell surface is typically a sialic acid (Neu5Ac). Increased sialylation usually indicates progression and poor prognosis of most carcinomas. Here, we utilize two human mammary epithelial cell lines, HB4A (breast normal cells) and T47D (breast cancer cells), as a model system to demonstrate differential surface glycans when treated with sialic acid under nutrient deprivation. Under a starved condition, sialic acid treatment of both cells resulted in increased activities of α2→3/6 sialyltransferases as demonstrated by solid phase assay using lectin binding. However, a very strong Maackia amurensis agglutinin I (MAL-I) staining on the membrane of sialic acid-treated T47D cells was observed, indicating an increase of Neu5Acα2→3Gal on the cell surface. To our knowledge, this is a first report showing the utility of lectins, particularly MAL-I, as a means to discriminate between normal and cancer cells after sialic acid treatment under nutrient deprivation. This method is sensitive and allows selective detection of glycan sialylation on a cancer cell surface.

The determination of genetic markers of age-related cancer pathologies in populations from Kazakhstan

Aging associates with a variety of pathological conditions such as cancer, cardiovascular, neurodegenerative, autoimmune diseases, and metabolic disorders. The oncogenic alterations overlap frequently with the genes linked to aging. Here, we show that several aging related genes may serve as the genetic risk factors for cervical and esophagus cancers. In our study, we analyzed samples obtained from 115 patients with esophageal and 207 patients with cervical cancer. The control groups were selected to match the ethnicity and age of cancer patients. We examined the genes involved in the processes of xenobiotics detoxification (GSTM1 and GSTT1), DNA repair (XRCC1 and XRCC3), and cell cycle regulation and apoptosis (CCND1 and TP53). Our study revealed that deletions of GSTT1 and GSTM1 genes or the distinct point mutations of XRCC1 gene are associated with cervical and esophageal cancers. These results will lead to development of screening for detection of individuals susceptible to esophageal and cervical cancers. Introduction of the screening programs will allow the early and effective preventive measures that will reduce cancer incidence and mortality in Kazakhstan.