Tumor and serum beta-2-microglobulin expression in women with breast cancer

All-in-One digital microfluidics pipeline for proteomic sample preparation and analysis

Highly sensitive and reproducible analysis of samples containing low amounts of protein is restricted by sample loss and the introduction of contaminants during processing. Here, we report an All-in-One digital microfluidic (DMF) pipeline for proteomic sample reduction, alkylation, digestion, isotopic labeling and analysis. The system features end-to-end automation, with integrated thermal control for digestion, optimized droplet additives for sample manipulation and analysis, and an automated interface to liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). Dimethyl labeling was integrated into the pipeline to allow for relative quantification of the trace samples at the nanogram level, and the new pipeline was applied to evaluating cancer cell lines and cancer tissue samples. Several known proteins (including HSP90AB1, HSPB1, LDHA, ENO1, PGK1, KRT18, and AKR1C2) and pathways were observed between model breast cancer cell lines related to hormone response, cell metabolism, and cell morphology. Furthermore, differentially quantified proteins (such as PGS2, UGDH, ASPN, LUM, COEA1, and PRELP) were found in comparisons of healthy and cancer breast tissues, suggesting potential utility of the All-in-One pipeline for the emerging application of proteomic cancer sub-typing. In sum, the All-in-One pipeline represents a powerful new tool for automated proteome processing and analysis, with the potential to be useful for evaluating mass-limited samples for a wide range of applications.

Role of beta(2)-microglobulin in the immune response in renal osteodystrophy

Renal osteodystrophy is the major cause of skeletal morbidity in dialysis patients. It is characterized by beta(2)-microglobulin (beta(2)M) amyloid deposition at the osteoarticular sites and a destructive arthropathy. beta(2)M is present on the surface of all nucleated cells as the small extracellular subunit of the major histocompatibility complex (MHC) class I molecule and actively participates in the immune response. Accumulating evidence suggests that beta(2)M plays a key role in the development of renal osteodystrophy through a T cell-mediated inflammatory immune mechanism.

Role of interleukin-6 in beta2-microglobulin-induced bone mineral dissolution

BACKGROUND

beta2-microglobulin (beta2m) amyloidosis is commonly seen in patients undergoing long-term dialysis. beta2m has been shown to induce in vitro bone mineral dissolution. The present study was designed to investigate the effect of beta2m on osteoblast function and the role of interleukin-6 (IL-6) on beta2m-induced bone resorption.

METHODS

Using neonatal mouse calvariae as well as primary osteoblasts and MC 3T3 osteoblast-like cells, IL-6 production, release, and gene expression were investigated with enzyme-linked immunosorbent assay (ELISA) and semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) techniques, respectively.

RESULTS

In calvariae, beta2m induced a time- and dose-dependent calcium release, which was maximum following a 48-hour incubation at a concentration of 10-5 mol/L. beta2m (10-6 mol/L) also induced a significant release of IL-6 from calvarial and primary osteoblastic cultures. Using 10-6 mol/L beta2m, the amount of IL-6 mRNA in MC 3T3 cells increased in a time-dependent fashion, which peaked at 3 hours and declined to baseline by 12 hours. In primary osteoblast cells, beta2m maximally increased IL-6 mRNA levels at 6 hours; however, they remained elevated up to 24 hours. Compared with control, the presence of beta2m significantly increased cell proliferation of both primary osteoblasts and MC 3T3 cells. To investigate osteoblastic function further, osteocalcin mRNA was quantitated. Incubation with beta2m for 3 to 24 hours did not alter the amount of osteocalcin mRNA in the MC 3T3 osteoblast cells.

CONCLUSION

beta2m affects bone metabolism by mechanisms that include increasing IL-6 gene expression and release, and enhancing osteoblast proliferation without affecting osteocalcin gene expression.

Correlation between tumour and serum beta 2m expression in patients with breast cancer

HLA class I antigens are composed of a major histocompatibility complex (MHC) encoded heavy chain that is associated non-covalently with a light chain beta-2 microglobulin (beta-2m). When the HLA complex is metabolized, beta-2m is shed into the serum. A large variety of human and experimental tumours have altered MHC class I expression. In a previous study we observed elevated mean beta-2m serum levels in breast cancer patients, as compared to controls. To study the relationship between tumour expression and serum levels, we examined 54 patients with breast cancer. Tumour beta-2m was determined by immunohistochemistry and serum levels by the ELISA technique. Of the 54 patients, 38 had low and 16 had high beta-2m expression on the tumour. There was a significant correlation between tumour beta-2m and serum beta-2m levels (P = 0.02), with patients whose tumours expressed high beta-2m having high serum beta-2m levels. There was an inverse correlation between tumour grade and tumour beta-2m expression which approached statistical significance (P = 0.06). These findings suggest that in a substantial number of patients the high serum levels derive from shedding of beta-2m from tumour cells. These levels may have implications for tumour growth and metastases due to influences on immunological responses.

Serum tumor markers for detection of bone metastasis in breast cancer patients

For the diagnosis of bone metastasis in breast cancer patients during systemic treatment serum tumor markers, including carbohydrate antigens 15-3 (CA 15-3) and 19-9 (CA 19-9), cancer antigen 125 (CA 125), alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), beta-2 microglobulin (BMG), ferritin, and tissue polypeptide antigen (determined by the M3 monoclonal antibody, TPS) were measured in 22 patients with known bone metastases and in 30 patients without documented metastases. The most useful single marker was CA 15-3. By stepwise discriminant analysis, it was found that 90% of the patients could be diagnosed truly by using the markers CA 15-3, BMG and ferritin. It is concluded that monitoring with combinations of tumor markers at regular intervals increases the diagnostic efficiency.