Background A disintegrin and metalloproteinase-12 (ADAM12) is a member of the greater ADAM family of enzymes: these are multifunctional, generally membrane-bound, zinc proteases for which there are forty genes known (21 of these appearing in humans). ADAM12 has been implicated in the pathogenesis of various cancers, liver fibrogenesis, hypertension, and asthma, and its elevation or decrease in human serum has been linked to these and other physiological/pathological conditions. Scope In this review, we begin with a brief overview of the ADAM family of enzymes and protein structure. We then discuss the role of ADAM12 in the progression and/or diagnosis of various disease conditions, and we will conclude with an exploration of currently known natural and synthetic inhibitors. Major Conclusions ADAM12 has potential to emerge as a successful drug target, although targeting the metalloproteinase domain with any specificity will be difficult to achieve due to structural similarity between the members of the ADAM and MMP family of enzymes. Overall, more research is required to establish ADAM12 being as a highly desirable biomarker and drug target of different diseases, and their selective inhibitors as potential therapeutic agents. General Significance Given the appearance of elevated levels of ADAM12 in various diseases, particularly breast cancer, our understanding of this enzyme both as a biomarker and a potential drug target could help make significant inroads into both early diagnosis and treatment of disease.

We have successfully synthesized a lipid containing the pyranine dye as the hydrophilic head group. This lipid was incorporated into liposomes with 1-palmitoyl-sn-glycero-3-phosphocholine as the major component. The resultant liposomes displayed differential enhancements in fluorescence emission intensity in the presence of nanomolar concentrations of different glycosaminoglycans. Linear discriminant analysis of the fluorescence response data demonstrate that the liposomes are able to distinguish between different GAGs. In addition, we also demonstrate that the liposomes incorporating the pyranine lipid are able to distinguish between dilute serum from healthy individuals and serum containing elevated chondroitin sulfate (simulated serum from an Alzheimer’s disease patient).

A liposome-based amplified detection system is presented for the cancer cell secreted pathogenic enzyme matrix metalloproteinase-9 which does not require the use of biological antibodies.

BackgroundThe ADAMs (A Disintegrin and Metalloproteinases) are a family of multi-domain, zinc-dependent metalloproteinase enzymes. ADAM 12 has been previously associated with the onset and progression of breast cancer, and elevated levels of ADAM 12 have been previously found in the urine of breast cancer patients. Aims of the current study are: 1) establish the viability of urinary ADAM 12 as a diagnostic marker for breast cancer, and 2) explore the effects of surgical tumor removal on the levels of urinary ADAM 12.MethodsA total of 96 patients have been recruited for this study, including 50 patients diagnosed with cancer, and 46 age-matched controls. Commercially available ELISA kits for ADAM 12 were used to quantify the presence and concentration of this enzyme in the urine from cancer patients with ductal carcinoma in situ (DCIS) and invasive breast cancer (IBC) both prior to any treatment and approximately two weeks following surgery, as well as from controls.ResultsWe find no statistically significant differences between the concentrations of ADAM 12 in the urine of breast cancer patients prior to treatment and that of their age-matched controls; however the concentration of ADAM 12, both alone and as a function of urine total protein, are significantly elevated following surgery (p < 0.0001). Patients who underwent a mastectomy have significantly higher urinary ADAM 12 concentrations than those who underwent a lumpectomy (significant at p = 0.0271).ConclusionsThese findings suggest that urinary ADAM 12 may not correlate directly with the status and stage of breast cancer as previously thought; rather these increases may be a result of tissue injury and inflammation from biopsy and surgical resection. Results of this study may suggest a need for biomarkers to be evaluated carefully in the context of tissue damage.

Though the aggregation of glycosaminoglycans (GAGs) in the presence of liposomes and divalent cations has been previously reported, the effect of different GAG species, as well as minor changes in GAG composition on the aggregates formed is yet unknown. If minor changes in GAG composition produce observable changes in liposome aggregate diameter or zeta potential, such a phenomenon may be used to detect potentially dangerous over-sulfated contaminants in heparin. We studied the mechanism of the interactions between heparin and its over-sulfated glycosaminoglycan contaminants with liposomes. Herein, we demonstrate that Mg2+ acts to shield the incoming glycosaminoglycans from the negatively-charged phosphate groups of the phospholipids, and that changes in the aggregate diameter and zeta potential are a function of glycosaminoglycan species and concentration, as well as liposome bilayer composition. These observations are supported by TEM studies. We have shown that organizational states of the liposome bilayers are influenced by the presence of GAG and excess Mg2+, resulting in a stabilizing effect which increases the Tm value of DSPC liposomes; the magnitude of this effect is also dependent on GAG species and concentration present. There is an inverse relationship between the percent change of aggregate diameter and percent change of aggregate zeta potential, as a function of GAG concentration in solution. Finally, we demonstrate that the diameter and zeta potential changes of POPC liposome aggregates in the presence of different over-sulfated heparin contaminants at low concentrations allow accurate detection of over-sulfated chondroitin sulfate at concentrations as low as 1 mol%.