Rationale: Coronary artery ligation to induce myocardial infarction (MI) in mice is typically performed by an invasive and time-consuming approach that requires ventilation and chest opening (classic method), often resulting in extensive tissue damage and high mortality. We developed a novel and rapid surgical method to induce MI that does not require ventilation.Objective: The purpose of this study was to develop and comprehensively describe this method and directly compare it to the classic method. Key Words: myocardial ischemia Ⅲ myocardial ischemia/reperfusion injury Ⅲ cardiac injury Ⅲ cardiac dysfunction Ⅲ mouse model C ardiovascular disease represents the leading cause of morbidity and death in developed countries. Coronary heart disease, which is the single largest cause of cardiovascular disease, is the narrowing of arteries over time caused by atherosclerotic plaques or the acute occlusion of the coronary artery by thrombosis, both of which lead to possible myocardial infarction (MI) and the eventual development of heart failure. 1,2 Protection from coronary heart disease-induced damage of the myocardium during myocardial ischemia/ reperfusion (I/R) injury has been a target of investigation for the development of innovative cardioprotective therapies. [3][4][5][6][7] The increase in the availability of various types of genetically manipulated mice has brought about the need for more efficient ways to induce myocardial damage for both molecular mechanistic studies and potentially therapeutic interventions. Two of the most common models used by researchers are permanent left main descending coronary artery (LCA) occlusion to induce a MI and also temporary coronary artery occlusion to induce I/R injury. 8,9 The I/R model is generally used to examine the short-term consequences of ischemic injury, whereas the MI model is usually used to investigate myocardial changes such as remodeling that occur over an extended period of time. Although a variety of surgical manipulations have been used during the past decade to induce the ischemic event, ligation of the LCA is still the most commonly practiced method. 3,9 -11 However, most investigators still use a method requiring ventilation and wide opening the chest (referred to as the classic method), which can cause extensive tissue damage, high surgical-related death and can also be quite time consuming for most surgeons. [12][13][14][15] Over the last few years, we have developed a new MI approach in mice that does not require ventilation. 11,16 -18 Complete characterization and description of this model has Original Methods and Results:

GlcNAcylation, a dynamic posttranslational modification, is involved in a wide range of biological processes and some human diseases. Although there is emerging evidence that some tumor-associated proteins are modified by GlcNAcylation, the role of GlcNAcylation in tumor progression remains unclear. Here, we show that GlcNAcylation enhances the migration/invasion of breast cancer cells in vitro and lung metastasis in vivo. The decrease of cell surface E-cadherin is the molecular mechanism underlying GlcNAcylation-induced breast cancer metastasis. p120 and β-catenin, but not E-cadherin, are GlcNAcylated; the GlcNAcylation of p120 and β-catenin might play roles in the decrease of cell surface E-cadherin. Moreover, immunohistochemistry analysis indicated that the global GlcNAcylation level in breast tumor tissues is elevated significantly as compared with that in the corresponding adjacent tissues; further, GlcNAcylation was significantly enhanced in metastatic lymph nodes compared with their corresponding primary tumor tissues. This is the first report to clearly elucidate the roles and mechanisms whereby GlcNAcylation influences the malignant properties of breast cancer cells. These results also suggest that GlcNAcylation might be a potential target for the diagnosis and therapy of breast cancer. Cancer Res; 70(15);

O-GlcNAc is a monosaccharide attached to serine or threonine hydroxyl moieties on numerous nuclear and cytoplasmic proteins; O-GlcNAcylation is dynamically regulated by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Although recent studies have shown that O-GlcNAcylation plays essential roles in breast cancer progression, it is also necessary to know whether O-GlcNAcylation is involved in other types of human cancer. In this study, O-GlcNAcylation levels and the expressions of OGT and OGA in human lung and colon cancer tissues were examined by immunohistochemistry analysis. We found that O-GlcNAcylation as well as OGT expression was significantly elevated in the cancer tissues compared with that in the corresponding adjacent tissues. Additionally, the roles of O-GlcNAcylation in the malignancy of lung and colon cancer were investigated in vitro. The results showed that O-GlcNAcylation markedly enhanced the anchorage-independent growth of lung and colon cancer cells; O-GlcNAcylation could also enhance lung and colon cancer invasion in a context-dependent manner. All together, this study suggests that O-GlcNAcylation might play important roles in lung and colon cancer formation and progression, and may be a valuable target for diagnosis and therapy of cancer.

BackgroundMicroRNAs are short regulatory RNAs that negatively modulate protein expression at a post-transcriptional and/or translational level and are deeply involved in the pathogenesis of several types of cancers. Specifically, microRNA-221 (miR-221) is overexpressed in many human cancers, wherein accumulating evidence indicates that it functions as an oncogene. However, the function of miR-221 in human osteosarcoma has not been totally elucidated. In the present study, the effects of miR-221 on osteosarcoma and the possible mechanism by which miR-221 affected the survival, apoptosis, and cisplatin resistance of osteosarcoma were investigated.Methodology/Principal FindingsReal-time quantitative PCR analysis revealed miR-221 was significantly upregulated in osteosarcoma cell lines than in osteoblasts. Both human osteosarcoma cell lines SOSP-9607 and MG63 were transfected with miR-221 mimic or inhibitor to regulate miR-221 expression. The effects of miR-221 were then assessed by cell viability, cell cycle analysis, apoptosis assay, and cisplatin resistance assay. In both cells, upregulation of miR-221 induced cell survival and cisplatin resistance and reduced cell apoptosis. In addition, knockdown of miR-221 inhibited cell growth and cisplatin resistance and induced cell apoptosis. Potential target genes of miR-221 were predicted using bioinformatics. Moreover, luciferase reporter assay and western blot confirmed that PTEN was a direct target of miR-221. Furthermore, introduction of PTEN cDNA lacking 3′-UTR or PI3K inhibitor LY294002 abrogated miR-221-induced cisplatin resistance. Finally, both miR-221 and PTEN expression levels in osteosarcoma samples were examined by using real-time quantitative PCR and immunohistochemistry. High miR-221 expression level and inverse correlation between miR-221 and PTEN levels were revealed in osteosarcoma tissues.Conclusions/SignificanceThese results for the first time demonstrate that upregulation of miR-221 induces the malignant phenotype of human osteosarcoma whereas knockdown of miR-221 reverses this phenotype, suggesting that miR-221 could be a potential target for osteosarcoma treatment.

BackgroundMicroRNAs (miRNAs) are a class of endogenously expressed, small noncoding RNAs, which suppress its target mRNAs at the post-transcriptional level. Studies have demonstrated that miR-34a, which is a direct target of the p53 tumor suppressor gene, functions as a tumor suppressor and is associated with the tumor growth and metastasis of various human malignances. However, the role of miR-34a in osteosarcoma has not been totally elucidated. In the present study, the effects of miR-34a on osteosarcoma and the possible mechanism by which miR-34a affected the tumor growth and metastasis of osteosarcoma were investigated.Methodology/Principal FindingOver-expression of miR-34a partially inhibited proliferation, migration and invasion of osteosarcoma cells in vitro, as well as the tumor growth and pulmonary metastasis of osteosarcoma cells in vivo. c-Met is a target of miR-34a, and regulates the migration and invasion of osteosarcoma cells. Osteosarcoma cells over-expressing miR-34a exhibited a significant decrease in the expression levels of c-Met mRNA and protein simultaneously. Finally, the results from bioinformatics analysis demonstrated that there were multiple putative targets of miR-34a that may be associated with the proliferation and metastasis of osteosarcoma, including factors in Wnt and Notch signaling pathways.Conclusion/SignificanceThe results presented in this study demonstrated that over-expression of miR-34a could inhibit the tumor growth and metastasis of osteosarcoma probably through down regulating c-Met. And there are other putative miR-34a target genes beside c-Met which could potentially be key players in the development of osteosarcoma. Since pulmonary metastases are responsible for mortality of patient carrying osteosarcoma, miR-34a may prove to be a promising gene therapeutic agent. It will be interesting to further investigate the mechanism by which miR-34a functions as a tumor suppressor gene in osteosarcoma.