Cancer cells decorate their surface with a dense layer of sialylated glycans by upregulating the expression of sialyltransferases and other glycogenes. Although sialic acids play a vital role in many biologic processes, hypersialylation in particular has been shown to contribute to cancer cell progression and metastasis. Accordingly, selective strategies to interfere with sialic acid synthesis might offer a powerful approach in cancer therapy. In the present study, we assessed the potential of a recently developed fluorinated sialic acid analogue (P-3F ax -Neu5Ac) to block the synthesis of sialoglycans in murine melanoma cells and the consequences on cell adhesion, migration, and in vivo growth. The results showed that P-3F ax -Neu5Ac readily caused depletion of a2,3-/a2,6-linked sialic acids in B16F10 cells for several days. Long-term inhibition of sialylation for 28 days was feasible without affecting cell viability or proliferation. Moreover, P-3F ax -Neu5Ac proved to be a highly potent inhibitor of sialylation even at high concentrations of competing sialyltransferase substrates. P-3F ax -Neu5Ac-treated cancer cells exhibited impaired binding to poly-L-lysine, type I collagen, and fibronectin and diminished migratory capacity. Finally, blocking sialylation of B16F10 tumor cells with this novel sialic acid analogue reduced their growth in vivo. These results indicate that P-3F ax -Neu5Ac is a powerful glycomimetic capable of inhibiting aberrant sialylation that can potentially be used for anticancer therapy. Mol Cancer Ther; 12(10); 1935-46. Ó2013 AACR.

Purpose To investigate the angiogenic changes in primary tumor tissue of renal cell carcinoma (RCC) patients treated with vascular endothelial growth factor (VEGF)-targeted therapy. Experimental design Phase II trials of VEGF pathway targeted therapy given prior to cytoreductive surgery were performed with metastatic RCC patients with the primary tumor in situ, to investigate the necessity of nephrectomy. Primary tumor tissues were obtained and assessed for angiogenesis parameters. Results were compared to similar analyses on untreated tumors. Results Sunitinib or bevacizumab pretreatment resulted in a significant reduction of microvessel density in the primary tumor. Also, an increase in vascular pericyte coverage was found in sunitinib-pretreated tumors, consistent with efficient angiogenesis inhibition. Expression of several key regulators of angiogenesis was suppressed in pretreated tissues, among which VEGFR-1 and -2, angiopoietin-1 and -2 and PDGF-B. In addition, apoptosis in tumor and endothelial cells was induced. Interestingly, in sunitinib-pretreated tissues a dramatic increase of the number of proliferating endothelial cells was observed, which was not the case in bevacizumab-pretreated tumors. A positive correlation with the interval between halting the therapy and surgery was found, suggesting a compensatory angiogenic response caused by the discontinuation of sunitinib treatment. Conclusion This study describes for the first time the angiostatic response in human primary renal cancers at the tissue level upon treatment with VEGF targeted therapy. Discontinuation of treatment with tyrosine kinase inhibitors leads to accelerated angiogenesis. The results of the current study contribute important data to the ongoing discussion on the discontinuation of treatment with kinase inhibitors.

Purpose: In brain tumors, cerebral edema is a significant source of morbidity and mortality. Recent studies have shown that inhibition of vascular endothelial growth factor (VEGF) signaling induces transient vascular normalization and reduces cerebral edema, resulting in a modest survival benefit in glioblastoma patients. During anti-VEGF treatment, circulating levels of angiopoietin (Ang)-2 remained high after an initial minor reduction. It is not known, however, whether Ang-2 can modulate anti-VEGF treatment of glioblastoma. Here, we used an orthotopic glioma model to test the hypothesis that Ang-2 is an additional target for improving the efficacy of current anti-VEGF therapies in glioma patients. Experimental Design: To recapitulate high levels of Ang-2 in glioblastoma patients during anti-VEGF treatment, Ang-2 was ectopically expressed in U87 glioma cells. Animal survival and tumor growth were assessed to determine the effects of Ang-2 and anti–VEGF receptor 2 (VEGFR2) treatment. We also monitored morphologic and functional vascular changes using multiphoton laser scanning microscopy and immunohistochemistry. Results: Ectopic expression of Ang-2 had no effect on vascular permeability, tumor growth, or survival, although it resulted in higher vascular density, with dilated vessels and reduced mural cell coverage. On the other hand, when combined with anti-VEGFR2 treatment, Ang-2 destabilized vessels without affecting vessel regression and compromised the survival benefit of VEGFR2 inhibition by increasing vascular permeability. VEGFR2 inhibition normalized tumor vasculature whereas ectopic expression of Ang-2 diminished the beneficial effects of VEGFR2 blockade by inhibiting vessel normalization. Conclusion: Cancer treatment regimens combining anti-VEGF and anti-Ang-2 agents may be an effective strategy to improve the efficacy of current anti-VEGF therapies. Clin Cancer Res; 16(14); 3618–27. ©2010 AACR.

Sialic acid sugars are overexpressed by cancer cells and contribute to the metastatic cascade at multiple levels. Therapeutic interference of sialic acids, however, has been difficult to pursue because of the absence of dedicated tools. Here we show that a rationally designed sialic acid-blocking glycomimetic (P-3F(ax)-Neu5Ac) successfully prevents cancer metastasis. Formulation of P-3F(ax)--Neu5Ac into poly(lactic-co-glycolic acid nanoparticles coated with antityrosinase-related protein-1 antibodies allowed targeted delivery of P-3F(ax)--Neu5Ac into melanoma cells, slow release, and long-term sialic acid blockade. Most importantly, intravenous injections of melanoma-targeting P-3F(ax)--Neu5Ac nanoparticles prevented metastasis formation in a murine lung metastasis model. These findings stress the importance of sialoglycans in cancer metastasis and advocate that sialic acid blockade using rationally designed glycomimetics targeted to cancer cells can effectively prevent cancer metastases. This targeting strategy to interfere with sialic acid-dependent processes is broadly applicable not only for different types of cancer but also in infection and inflammation.

The bioengineering of a replacement kidney has been proposed as an approach to address the growing shortage of donor kidneys for the treatment of chronic kidney disease. One approach being investigated is the recellularization of kidney scaffolds. In this study, we present several key advances toward successful re‐endothelialization of whole kidney matrix scaffolds from both rodents and humans. Based on the presence of preserved glycosoaminoglycans within the decelullarized kidney scaffold, we show improved localization of delivered endothelial cells after preloading of the vascular matrix with vascular endothelial growth factor and angiopoietin 1. Using a novel simultaneous arteriovenous delivery system, we report the complete re‐endothelialization of the kidney vasculature, including the glomerular and peritubular capillaries, using human inducible pluripotent stem cell –derived endothelial cells. Using this source of endothelial cells, it was possible to generate sufficient endothelial cells to recellularize an entire human kidney scaffold, achieving efficient cell delivery, adherence, and endothelial cell proliferation and survival. Moreover, human re‐endothelialized scaffold could, in contrast to the non‐re‐endothelialized human scaffold, be fully perfused with whole blood. These major advances move the field closer to a human bioengineered kidney.

Breast cancer is one of the most common causes of cancer-related deaths in women. The estrogen receptor (ERα) is well known for having growth promoting effects in breast cancer. Recently, we have identified DC-SCRIPT (ZNF366) as a co-suppressor of ERα and as a strong and independent prognostic marker in ESR1 (ERα gene)-positive breast cancer patients. In this study, we further investigated the molecular mechanism on how DC-SCRIPT inhibits breast cancer cell growth. DC-SCRIPT mRNA levels from 190 primary ESR1-positive breast tumors were related to global gene expression, followed by gene ontology and pathway analysis. The effect of DC-SCRIPT on breast cancer cell growth and cell cycle arrest was investigated using novel DC-SCRIPT-inducible MCF7 breast cancer cell lines. Genome-wide expression profiling of DC-SCRIPT-expressing MCF7 cells was performed to investigate the effect of DC-SCRIPT on cell cycle-related gene expression. Findings were validated by real-time PCR in a cohort of 1,132 ESR1-positive breast cancer patients. In the primary ESR1-positive breast tumors, DC-SCRIPT expression negatively correlated with several cell cycle gene ontologies and pathways. DC-SCRIPT expression strongly reduced breast cancer cell growth in vitro, breast tumor growth in vivo, and induced cell cycle arrest. In addition, in the presence of DC-SCRIPT, multiple cell cycles related genes were differentially expressed including the tumor suppressor gene CDKN2B. Moreover, in 1,132 primary ESR1-positive breast tumors, DC-SCRIPT expression also correlated with CDKN2B expression. Collectively, these data show that DC-SCRIPT acts as a novel regulator of CDKN2B and induces cell cycle arrest in ESR1-positive breast cancer cells.Electronic supplementary materialThe online version of this article (doi:10.1007/s10549-015-3281-y) contains supplementary material, which is available to authorized users.

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350 Background: Angiogenic changes in primary tumor tissue of renal cell carcinoma (RCC) patients treated with VEGF-targeted therapy has not been previously studied. Methods: A total of 57 primary tumor samples from various retrospective and prospective studies of presurgical sunitinib or bevacizumab were used. In these studies targeted therapy was given with the primary tumor in situ prior to cytoreductive nephrectomy, to investigate impact of therapy on primary tumors. Primary tumor tissues were assessed for microvessel density (MVD), proliferating endothelial cells, pericyte coverage, apoptosis of tumor or endothelial cells and molecular expression of angiogenesis regulators. Results of tumors pretreated with sunitinib discontinued at different intervals before surgery, were compared to similar analyses of untreated and bevacizumab-pretreated tumors. Results: Sunitinib and bevacizumab pretreatment resulted in a significant reduction of MVD, as well as an increase in vascular pericyte coverage in the primary tumor (sunitinib samples) consistent with efficient angiogenesis inhibition. Expression of several key regulators of angiogenesis were found to be suppressed in sunitinib pretreated tissues, among which VEGFR-1 and -2, angiopoietin-1 and -2 and PDGF-B. Apoptosis was induced both by sunitinib and bevacizumab pretreatment. Interestingly, in sunitinib pretreated tissues a dramatic increase of the number of proliferating endothelial cells was observed, which was not the case in bevacizumab pretreated and untreated tumors. A positive correlation with the interval between halting the therapy and surgery was found, suggesting a compensatory angiogenic response caused by the discontinuation of sunitinib treatment. Conclusions: This study describes the antiangiogenic response in human primary renal cancers upon treatment with VEGF targeted therapy. Treatment discontinuation of tyrosine kinase inhibitors with short half life leads to accelerated angiogenesis. The results of the current study contribute important data to the ongoing discussion on the discontinuation of treatment with tyrosine kinase inhibitors.