Altered glycosylation of glycodelin in endometrial carcinoma.

Glycodelin is a major glycoprotein expressed in reproductive tissues, like secretory and decidualized endometrium. It has several reproduction related functions that are dependent on specific glycosylation, but it has also been found to drive differentiation of endometrial carcinoma cells toward a less malignant phenotype. Here we aimed to elucidate whether the glycosylation and function of glycodelin is altered in endometrial carcinoma as compared with a normal endometrium. We carried out glycan structure analysis of glycodelin expressed in HEC-1B human endometrial carcinoma cells (HEC-1B Gd) by mass spectrometry glycomics strategies. Glycans of HEC-1B Gd were found to comprise a typical mixture of high-mannose, hybrid, and complex-type N-glycans, often containing undecorated LacNAc (Galß1-4GlcNAc) antennae. However, several differences, as compared with previously reported glycan structures of normal human decidualized endometrium-derived glycodelin isoform, glycodelin-A (GdA), were also found. These included a lower level of sialylation and more abundant poly-LacNAc antennae, some of which are fucosylated. This allowed us to select lectins that showed different binding to these classes of glycodelin. Despite the differences in glycosylation between HEC-1B Gd and GdA, both showed similar inhibitory activity on trophoblast cell invasion and peripheral blood mononuclear cell proliferation. For the detection of cancer associated glycodelin, we established a novel in situ proximity-ligation based histochemical staining method using a specific glycodelin antibody and UEAI lectin. We found that the UEAI reactive glycodelin was abundant in endometrial carcinoma, but virtually absent in normal endometrial tissue even when glycodelin was strongly expressed. In conclusion, we established a histochemical staining method for the detection of endometrial carcinoma-associated glycodelin and showed that this specific glycodelin is exclusively expressed in cancer, not in normal endometrium. Similar methods can be used for studies of other glycoproteins.

Metformin increases glucose uptake and acts renoprotectively by reducing SHIP2 activity.

Metformin, the first-line drug to treat type 2 diabetes (T2D), inhibits mitochondrial glycerolphosphate dehydrogenase in the liver to suppress gluconeogenesis. However, the direct target and the underlying mechanisms by which metformin increases glucose uptake in peripheral tissues remain uncharacterized. Lipid phosphatase Src homology 2 domain-containing inositol-5-phosphatase 2 (SHIP2) is upregulated in diabetic rodent models and suppresses insulin signaling by reducing Akt activation, leading to insulin resistance and diminished glucose uptake. Here, we demonstrate that metformin directly binds to and reduces the catalytic activity of the recombinant SHIP2 phosphatase domain in vitro. Metformin inhibits SHIP2 in cultured cells and in skeletal muscle and kidney of db/db mice. In SHIP2-overexpressing myotubes, metformin ameliorates reduced glucose uptake by slowing down glucose transporter 4 endocytosis. SHIP2 overexpression reduces Akt activity and enhances podocyte apoptosis, and both are restored to normal levels by metformin. SHIP2 activity is elevated in glomeruli of patients with T2D receiving nonmetformin medication, but not in patients receiving metformin, compared with people without diabetes. Furthermore, podocyte loss in kidneys of metformin-treated T2D patients is reduced compared with patients receiving nonmetformin medication. Our data unravel a novel molecular mechanism by which metformin enhances glucose uptake and acts renoprotectively by reducing SHIP2 activity.-Polianskyte-Prause, Z., Tolvanen, T. A., Lindfors, S., Dumont, V., Van, M., Wang, H., Dash, S. N., Berg, M., Naams, J.-B., Hautala, L. C., Nisen, H., Mirtti, T., Groop, P.-H., Wähälä, K., Tienari, J., Lehtonen, S. Metformin increases glucose uptake and acts renoprotectively by reducing SHIP2 activity.

LRG1 and SDR16C5 protein expressions differ according to HPV status in oropharyngeal squamous cell carcinoma.

The increasing incidence of oropharyngeal squamous cell carcinoma (OPSCC) is primarily due to human papillomavirus, and understanding the tumor biology caused by the virus is crucial. Our goal was to investigate the proteins present in the serum of patients with OPSCC, which were not previously studied in OPSCC tissue. We examined the difference in expression of these proteins between HPV-positive and -negative tumors and their correlation with clinicopathological parameters and patient survival. The study included 157 formalin-fixed, paraffin-embedded tissue samples and clinicopathological data. Based on the protein levels in the sera of OPSCC patients, we selected 12 proteins and studied their expression in HPV-negative and HPV-positive OPSCC cell lines. LRG1, SDR16C5, PIP4K2C and MVD proteins were selected for immunohistochemical analysis in HPV-positive and -negative OPSCC tissue samples. These protein´s expression levels were compared with clinicopathological parameters and patient survival to investigate their clinical relevance. LRG1 expression was strong in HPV-negative whereas SDR16C5 expression was strong in HPV-positive tumors. Correlation was observed between LRG1, SDR16C5, and PIP4K2C expression and patient survival. High expression of PIP4K2C was found to be an independent prognostic factor for overall survival and expression correlated with HPV-positive tumor status. The data suggest the possible role of LRG1, SDR16C5 and PIP4K2C in OPSCC biology.

Ebselen enhances insulin sensitivity and decreases oxidative stress by inhibiting SHIP2 and protects from inflammation in diabetic mice.

Ebselen, a multifunctional organoselenium compound, has been recognized as a potential treatment for diabetes-related disorders. However, the underlying mechanisms whereby ebselen regulates metabolic pathways remain elusive. We discovered that ebselen inhibits lipid phosphatase SHIP2 (Src homology 2 domain-containing inositol-5-phosphatase 2), an emerging drug target to ameliorate insulin resistance in diabetes. We found that ebselen directly binds to and inhibits the catalytic activity of the recombinant SHIP2 phosphatase domain and SHIP2 in cultured cells, the skeletal muscle and liver of the diabetic db/db mice, and the liver of the SHIP2 overexpressing (SHIP2-Tg) mice. Ebselen increased insulin-induced Akt phosphorylation in cultured myotubes, enhanced insulin sensitivity and protected liver tissue from lipid peroxidation and inflammation in the db/db mice, and improved glucose tolerance more efficiently than metformin in the SHIP2-Tg mice. SHIP2 overexpression abrogated the ability of ebselen to induce glucose uptake and reduce ROS production in myotubes and blunted the effect of ebselen to inhibit SHIP2 in the skeletal muscle of the SHIP2-Tg mice. Our data reveal ebselen as a potent SHIP2 inhibitor and demonstrate that the ability of ebselen to ameliorate insulin resistance and act as an antioxidant is at least in part mediated by the reduction of SHIP2 activity.

Glycodelin expression associates with differential tumour phenotype and outcome in sporadic and familial non-BRCA1/2 breast cancer patients.

Glycodelin (encoded by PAEP gene) is a secreted lipocalin protein mainly expressed in reproductive tissues, but also in several tumour types. In the breast, glycodelin is expressed both in normal epithelial and cancerous tissue. To investigate the association of glycodelin with clinicopathological features of breast cancer and outcome of patients we evaluated the protein expression of glycodelin in a large series of breast tumours. Immunohistochemical analysis of tissue microarrays was used to study glycodelin expression on 399 sporadic and 436 familial non-BRCA1/2 tumours with strong family history. Gene expression analysis was used to define genes co-expressed with PAEP in sporadic and familial non-BRCA1/2 breast tumours. In the sporadic series, the glycodelin expression associated with low proliferation rate (P < 0.001), with a tendency towards well-differentiated tumours (grades 1 and 2, P = 0.012) and high cyclin D1 (P = 0.034) expression. However, in familial non-BRCA1/2 cases with strong family history glycodelin expression associated with a less favourable phenotype, i.e. positive lymph node status (P = 0.003) and HER2-positive tumours (P = 0.009). Moreover, the patients with glycodelin-positive tumours had an increased risk for distant metastases (P = 0.001) and in multivariate analysis glycodelin expression was an independent predictor of metastasis (hazard ratio (HR) = 2.22, 95% confidence interval (95% CI) = 1.22-4.03, P = 0.009) in familial non-BRCA1/2 breast cancer. Gene expression analysis further revealed different gene expression profiles correlating with the PAEP expression in the sporadic and familial non-BRCA1/2 breast cancers. Our findings suggest differential progression pathways in the sporadic and familial non-BRCA1/2 breast tumours expressing glycodelin.

Novel Sulfonanilide Inhibitors of SHIP2 Enhance Glucose Uptake into Cultured Myotubes.

A series of substituted sulfonanilide analogs were prepared and evaluated as novel potent inhibitors of SH2 domain-containing inositol polyphosphate 5'-phosphatase 2 (SHIP2). SHIP2 has been shown to be a new attractive target for the treatment of insulin resistance in type 2 diabetes mellitus (T2D), which can lead to life-threatening diabetic kidney disease (DKD). Amongst the synthesized compounds, the two most promising candidates, 10 and 11, inhibited SHIP2 significantly. Additionally, these compounds induced Akt activation in a dose-dependent manner, increased the presence of glucose transporter 4 at the plasma membrane, and enhanced glucose uptake in cultured myotubes in vitro at lower concentrations than metformin, the most widely used antidiabetic drug. These results show that the novel SHIP2 inhibitors have insulin sensitizing capacity and provide prototypes for further drug development for T2D and DKD.

The role of glycodelin in cell differentiation and tumor growth.

Glycodelin is a lipocalin family glycoprotein expressed mainly in reproductive tissues. It is involved in cell recognition, and its relationship with epithelial differentiation is well established. Glycodelin actually appears to drive epithelial differentiation. The evidence comes from studies employing endometrial and breast cancer cell lines. First, transfection of glycodelin cDNA into glycodelin-negative carcinoma cells results in reduced expression of oncogenes, increased expression of tumor suppressor genes, increased cell differentiation, and reduced carcinoma cell growth. Second, histone deacetylase inhibitors (HDACIs) induce glycodelin synthesis in endometrial cancer cells concomitantly with cell differentiation. This effect is blocked by specific down-regulation of glycodelin by RNA interference, suggesting that the effects of HDACIs are mediated by glycodelin. We recently found that glycodelin not only reduces carcinoma cell growth in vitro, but glycodelin cDNA transfection to MCF-7 breast carcinoma cells also reduces growth of these cells in vivo, demonstrated by xenograft tumor growth in mouse mammary fat pads. These results strongly suggest that glycodelin acts as a tumor suppressor in breast cancer. The findings are compatible with the observations that certain types of glycodelin-expressing ovarian and breast cancers have a more favorable prognosis compared to glycodelin non-expressing tumors. This research has therefore introduced a novel mechanism to control cancer cell growth. In this communication we review the differentiation-related effects of glycodelin.

Glycodelin reduces breast cancer xenograft growth in vivo.

Malignant growth is characterized by loss of cell differentiation, uncontrolled proliferation and resistance to apoptosis. Many tumor suppressor genes that protect cells against malignant transformation regulate cell differentiation. Here, we show for the first time that glycodelin, a differentiation-related protein, reduces breast cancer tumor growth in vivo. We found that glycodelin cDNA-transfected MCF-7 breast cancer cells showed a differentiated phenotype and produced smaller tumors in mouse mammary fat pads compared with control-transfected cells. Glycodelin-induced differentiation was associated with reduced expression of oncogenes and increased expression of tumor suppressor genes. Our results suggest that glycodelin acts as a tumor suppressor in breast cancer. This may explain its reported association with a more favorable prognosis in some cancers.

Repressed PKCδ activation in glycodelin-expressing cells mediates resistance to phorbol ester and TGFß.

Glycodelin is a glycoprotein mainly expressed in well-differentiated epithelial cells in reproductive tissues. In normal secretory endometrium, the expression of glycodelin is abundant and regulated by progesterone. In hormone-related cancers glycodelin expression is associated with well-differentiated tumors. We have previously found that glycodelin drives epithelial differentiation of HEC-1B endometrial adenocarcinoma cells, resulting in reduced tumor growth in a preclinical mouse model. Here we show that glycodelin-transfected HEC-1B cells have repressed protein kinase C delta (PKCδ) activation, likely due to downregulation of PDK1, and are resistant to phenotypic change and enhanced migration induced by phorbol 12-myristate 13-acetate (PMA). In control cells, which do not express glycodelin, the effects of PMA were abolished by using PKCδ and PDK1 inhibitors, and knockdown of PKCδ, MEK1 and 2, or ERK1 and 2 by siRNAs. Similarly, transforming growth factor ß (TGFß)-induced phenotypic change was only seen in control cells, not in glycodelin-producing cells, and it was mediated by PKCδ. Taken together, these results strongly suggest that PKCδ, via MAPK pathway, is involved in the glycodelin-driven cell differentiation rendering the cells resistant to stimulation by PMA and TGFß.