Astrocyte-elevated gene-1 mediates insulin-like growth factor 1-induced the progression of cardiac myxoma

Astrocyte elevated gene-1 (AEG-1) and the A(E)Ging HIV/AIDS-HAND

Recent attempts to analyze human immunodeficiency virus (HIV)-1-induced gene expression changes in astrocytes uncovered a multifunctional oncogene, astrocyte elevated gene-1 (AEG-1). Our previous studies revealed that AEG-1 regulates reactive astrocytes proliferation, migration and inflammation, hallmarks of aging and CNS injury. Moreover, the involvement of AEG-1 in neurodegenerative disorders, such as Huntington's disease and migraine, and its induction in the aged brain suggest a plausible role in regulating overall CNS homeostasis and aging. Therefore, it is important to investigate AEG-1 specifically in aging-associated cognitive decline. In this study, we decipher the common mechanistic links in cancer, aging and HIV-1-associated neurocognitive disorders that likely contribute to AEG-1-based regulation of astrocyte responses and function. Despite AEG-1 incorporation into HIV-1 virions and its induction by HIV-1, tumor necrosis factor-α and interleukin-1β, the specific role(s) of AEG-1 in astrocyte-driven HIV-1 neuropathogenesis are incompletely defined. We propose that AEG-1 plays a central role in a multitude of cellular stress responses involving mitochondria, endoplasmic reticulum and the nucleolus. It is thus important to further investigate AEG-1-based cellular and molecular regulation in order to successfully develop better therapeutic approaches that target AEG-1 to combat cancer, HIV-1 and aging.

The involvement of hematopoietic pre-B cell leukemia transcription factor-interacting protein in regulating epithelial-mesenchymal transition of human spinal glioblastoma

To date, hematopoietic pre-B cell leukemia transcription factor-interacting protein (HPIP), a co-repressor for the transcription factor PBX, has been involved into the initiation and onset in a wide variety of cancers. However, the molecular mechanisms underlying HPIP-induced epithelial-mesenchymal transition (EMT) in the spinal glioblastoma have been under investigation. In the present study, spinal glioblastoma tissues, U87, and U251 cell lines were used and subjected to in vitro assays, such as RT-PCR, and Western blot. Here, in vitro assays revealed that HPIP mRNA and protein were highly expressed in five cases of spinal glioblastoma tissues, compared with non-tumor tissues. Subsequently, in vitro experiments demonstrated HPIP promoted the U87 and U251 cell growth and regulated the G1/S phase transitions in U87 and U251 cell cycle, respectively, accompanied by the increased expression of cyclin A2, cyclin B1, and cyclin D1. Furthermore, HPIP increased the expression of N-cadherin, Slug, and MMP2, and decreased the expression of E-cadherin. By contrast, knockdown of HPIP reversed HPIP-induced EMT biomarkers, migration, and invasion in U87 and U251 cells. In conclusion, our findings identified HPIP plays an important role in the progression and EMT of spinal glioblastoma, by which cell growth is improved. Thus, HPIP gene or protein could act as a useful target in the clinical practice.

The involvement of myocyte enhancer factor 2D in regulating tumor biology of cardiac myxoma

The pro-survival transcription factor myocyte enhancer factor 2D (MEF2D) is identified to exhibit pro-tumor effects based on clinical and experimental studies. However, the detailed mechanisms underlying IGF-1-MEF2D pathway-induced tumor biology in cardiac myxoma (CM) was not clear. Here, we investigated the role of MEF2D in CM tissues and cells using RT-PCR, western blot, gene silencing, et al. Our findings revealed MEF2D was significantly increased in CM tissues compared with adjacent normal tissues and closely related to tumor size. In vitro assay demonstrated that IGF-1 enhanced CM cell proliferation in a time-dependent fashion. However, knockdown of MEF2D reversed the IGF-1-induced proliferative effects on CM cells in a time-dependent fashion and further resulted in cell cycle arrest. Based on the molecular level, IGF-1 enhanced the expression of epidermal growth factor receptor (EGFR) and matrix metalloprotein 9 (MMP9) in CM cells, whereas knockdown of MEF2D was able to reduce the expression of EGFR and MMP9 compared with vector control. Furthermore, we found knockdown of MEF2D directly affected G1/S transition in cultured CM cells. In conclusion, MEF2D regulates IGF-1-induced proliferation and apoptosis in CM development, indicating IGF-1-MEF2D pathway may be a useful target for treatment.