Serglycin is a proteoglycan expressed by some malignant cells. It promotes metastasis and protects some tumor cells from complement system attack. In the present study, we show for the first time the in situ expression of serglycin by breast cancer cells by immunohistochemistry in patients’ material. Moreover, we demonstrate high expression and constitutive secretion of serglycin in the aggressive MDA-MB-231 breast cancer cell line. Serglycin exhibited a strong cytoplasmic staining in these cells, observable at the cell periphery in a thread of filaments near the cell membrane, but also in filopodia-like structures. Serglycin was purified from conditioned medium of MDA-MB-231 cells, and represented the major proteoglycan secreted by these cells, having a molecular size of ∼250 kDa and carrying chondroitin sulfate side chains, mainly composed of 4-sulfated (∼87%), 6-sulfated (∼10%) and non-sulfated (∼3%) disaccharides. Purified serglycin inhibited early steps of both the classical and the lectin pathways of complement by binding to C1q and mannose-binding lectin. Stable expression of serglycin in less aggressive MCF-7 breast cancer cells induced their proliferation, anchorage-independent growth, migration and invasion. Interestingly, over-expression of serglycin lacking the glycosaminoglycan attachment sites failed to promote these cellular functions, suggesting that glycanation of serglycin is a pre-requisite for its oncogenic properties. Our findings suggest that serglycin promotes a more aggressive cancer cell phenotype and may protect breast cancer cells from complement attack supporting their survival and expansion.

Proteoglycans are major constituents of the extracellular matrices as well as the cell surfaces and basement membranes. They play key roles in supporting the dynamic extracellular matrix by generating complex structural networks with other macromolecules and by regulating cellular phenotypes and signaling. It is becoming evident, however, that proteolytic enzymes are required partners for matrix remodeling and for modulating cell signaling via matrix constituents. Proteinases contribute to all stages of diseases, particularly in cancer development and progression, and contextually participate in either the removal of damaged products or in the processing of matrix molecules and signaling receptors. Indeed, the dynamic interplay between proteoglycans and proteolytic enzymes is a crucial biological step that contributes to the pathophysiology of cancer and inflammation. Moreover, proteoglycans are implicated in the expression and secretion of proteolytic enzymes and often modulate their activities. In this review we present emerging biological roles of proteoglycans and proteinases with special emphasis on their complex interplay. We critically evaluate this important proteoglycan-proteinase interactome and discuss future challenges of potentially targeting this axis in the treatment of cancer.

The pathogenesis of colorectal carcinoma (CRC) is a complex process that involves the recruitment of both genetic and epigenetic mechanisms. Recent studies underline the cardinal role of small, noncoding RNA molecules, called microRNAs (miRs), in the pathobiology of numerous physiological and pathological processes, including oncogenesis. MiR biogenesis and maturation is mainly regulated by the nuclear ribonuclease Drosha and the cytoplasmic ribonucleases Dicer and Ago2. In the present study, we investigated the expression and distribution of these molecules in three colon cancer cell lines and in human CRC samples. Drosha, Dicer, and Ago2 mRNA and protein expression was assessed with real-time PCR, western blotting, and immunofluorescence. Our experiments showed that Drosha, Dicer, and Ago2 were expressed in all the cell lines and in the majority of the CRC samples examined. The mRNA levels of Dicer were significantly augmented in stage III compared to stage II tumors. Our results suggest that Drosha, Dicer, and Ago2 are possibly implicated in CRC pathobiology and that Dicer might have a role in the progression of these tumors to advanced stages.

Angiogenesis is considered to be a regulating factor of vascular development and growth for malignant gliomas, including glioblastoma multiforme (GBM) and anaplastic astrocytomas. The mechanism of angiogenesis is primarily mediated by hypoxia through chronic activation of the HIF pathway leading to the production of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor. Alternatively, it can be triggered by genetic factors. The VEGF/VEGFR-2 is the predominant angiogenic signalling pathway in malignant gliomas. Currently, anti-angiogenic molecularly targeted therapies, including administration of monoclonal antibodies or tyrosine kinase inhibitors (TKIs), are being increasingly adopted for treating GBMs. This approach is based on the ability of anti-VEGFRs monoclonal antibodies to decrease vascular permeability and perfusion, whereas the use of TKIs is mainly based on their capacity to interfere with cell communication, receptor signaling and growth of tumours. Our aim is to review current knowledge on angiogenesis as a molecular pathogenetic mechanism of malignant gliomas and to critically look at and discuss antiangiogenic molecularly targeted therapies for these brain malignancies. We also highlight areas of future research to pursue.

ILK overexpression in human CRC associates with EMT and CSC traits, contributing to tumor progression and chemoresistance.