Glycoprotein asporin as a novel player in tumour microenvironment and cancer progression.
BACKGROUND
Small leucine rich proteoglycans (SLRPs), major non-collagen components of the extracellular matrix (ECM), have multiple biological roles with diverse effects. Asporin, a member of the SLRPs class I, competes with other molecules in binding to collagen and affects its mineralization. Its role in cancer is only now being elucidated.


METHODS
The PubMed online database was used to search relevant reviews and original articles. Furthermore, altered asporin expression was analysed in publicly available genome-wide expression data at the Gene Expression Omnibus database.


RESULTS
Polymorphisms in the N-terminal polyaspartate domain, which binds calcium, are associated with osteoarthritis and prostate cancer. Asporin also promotes the progression of scirrhous gastric cancer where it is required for coordinated invasion by cancer associated fibroblasts and cancer cells. Besides the enhanced expression of asporin observed in multiple cancer types, such as breast, prostate, gastric, pancreas and colon cancer, tumour suppressive effects of asporin were described in triple-negative breast cancer. We also discuss a number of factors modulating asporin expression in different cell types relevant for alterations toing the tumour microenvironment.


CONCLUSIONS
The apparent contradicting tumour promoting and suppressive effects of asporin require further investigation. Deciphering the role of asporin and other SLRPs in tumour-stroma interactions is needed for a better understanding of cancer progression and potentially also for novel tumour microenvironment based therapies.
Department of Clinical and Molecular Pathology and Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic.
Dana
D
Simkova
Department of Clinical and Molecular Pathology and Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic.
Gvantsa
G
Kharaishvili
Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Brno, Czech Republic.
Eva
E
Slabakova
Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
Paul G
PG
Murray
Department of Clinical and Molecular Pathology and Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic.
Jan
J
Bouchal
D000273:Adipose Tissue / Q000502:physiology; D018450:Disease Progression; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000502:physiology; D009369:Neoplasms / Q000209:etiology* / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics; D059016:Tumor Microenvironment / Q000235:genetics / Q000502:physiology*
C439889:ASPN protein, human; D016326:Extracellular Matrix Proteins; D035683:MicroRNAs
adipose tissue; asporin; breast; cancer; gastric; miRNAs; polymorphism; prostate