Metabolic Profiling of a Porcine Combat Trauma-Injury Model Using NMR and Multi-Mode LC-MS Metabolomics-A Preliminary Study.

Profiles of combat injuries worldwide have shown that penetrating trauma is one of the most common injuries sustained during battle. This is usually accompanied by severe bleeding or hemorrhage. If the soldier does not bleed to death, he may eventually succumb to complications arising from trauma hemorrhagic shock (THS). THS occurs when there is a deficiency of oxygen reaching the organs due to excessive blood loss. It can trigger massive metabolic derangements and an overwhelming inflammatory response, which can subsequently lead to the failure of organs and possibly death. A better understanding of the acute metabolic changes occurring after THS can help in the development of interventional strategies, as well as lead to the identification of potential biomarkers for rapid diagnosis of hemorrhagic shock and organ failure. In this preliminary study, a metabolomic approach using the complementary platforms of nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography coupled with mass spectrometry (LC-MS) was used to determine the metabolic changes occurring in a porcine model of combat trauma injury comprising of penetrating trauma to a limb with hemorrhagic shock. Several metabolites associated with the acute-phase reaction, inflammation, energy depletion, oxidative stress, and possible renal dysfunction were identified to be significantly changed after a thirty-minute shock period.

Targeting metallothionein for prognosis and treatment of breast cancer.

Breast cancer is a disease that has plagued many women globally. The rapid rise in the incidence rate has prompted the rigorous search to understand its etiology and find better management strategies for this disease. Metallothionein (MT) belongs to a family of metal-binding proteins where dysregulated expression of this protein has been observed in invasive breast ductal carcinomas. Since its discovery in equine kidney, functions of MT have extended beyond the initial role of heavy metal detoxification to promoting tumorigenesis. MT, which was reported to be highly expressed in many tumors including breast cancers, is known to regulate key processes such as cell proliferation, apoptosis and even chemoresistance. In this patent review, we shall evaluate the roles of 10 functional isoforms of MT in breast neoplasia and discuss the utility of MT isoforms as biomarkers for prognosis. Strategies targeting MT for treatment could provide alternatives to overcome this dreaded disease which has claimed the lives of many women.

Silencing the Metallothionein-2A gene induces entosis in adherent MCF-7 breast cancer cells.

The presence of a live cell cohabiting within another cell has fascinated scientists for many decades. Far from being a spurious event, many have attempted to uncover the molecular mechanism underlying this phenomenon. In this study, we observed anchorage-dependent MCF-7 cells internalizing neighboring epithelial cells (entosis) after siRNA-mediated silencing of the Metallothionein-2A (MT-2A) gene. MTs belong to a family of low-molecular weight proteins, which bind metal ions endogenously and its over-expression has been reported in a variety of cancers that include breast, prostate, and colon. We provide microscopic evidence at light and ultrastructural levels of the occurrence of entosis after altering MT expression in a subpopulation of MCF-7 breast cancer cells by silencing the MT-2A gene. Our results demonstrate that adheren junctions may play important roles in the formation of cell-in-cell cytostructure after MT-2A gene downregulation and the entotic process does not appear to involve genes associated with autophagy. Interiorized cells often underwent lysosomal degradation within the cytoplasmic body of the engulfing cell. It would appear that a subset of breast cancer cells could die via entosis after MT-2A gene silencing.

Over-expression of metallothionein predicts chemoresistance in breast cancer.

Metallothionein (MT) plays a role in fundamental cellular processes such as proliferation, apoptosis and differentiation. We examined MT expression in women with invasive breast ductal carcinoma who underwent mastectomy/lumpectomy without neo-adjuvant treatment. We showed that MT was over-expressed in 87.9% of breast cancer tissues examined, with the mean percentage of positive cells at 30%. There were two patterns of MT expression: predominantly cytoplasmic in 75.9% and nuclear in 24.1% of MT-positive cases. Higher MT scores were associated with poorer histological grade (p = 0.009) but were independent of age, tumour size and oestrogen receptor status. For patients who were treated with adjuvant chemotherapy (cyclophosphamide/methotrexate/5 fluorouracil- or doxorubicin-based regimes), those with high MT expression had a significantly lower recurrence-free survival (p = 0.048), suggesting a role of MT in predicting disease recurrence. Down-regulation of MT in MCF-7 cells by silencing the MT-2A gene (the most abundantly expressed of the 10 known functional MT isoforms) increased chemosensitivity of the cells to doxorubicin. To examine the mechanisms underlying these clinical data, we used siRNAs to decrease MT-2A mRNA expression and protein expression. In MT down-regulated cells challenged with the IC(50) concentration of doxorubicin, we observed a significant reduction in cell viability. Cell cycle analysis also revealed a corresponding increase in apoptosis in the MT down-regulated cells following doxorubicin exposure, showing that down-regulation of MT increased susceptibility to doxorubicin cytotoxicity. The data suggest that MT could be a potential marker of chemoresistance and a molecular therapeutic target.