Hypoxic Stimulation Of Egr-1 Cells Of Microtubule Stabilizing Effect

Early growth response gene-1 (Egr-1) transcription factors which contain a DNA-binding domain of three zinc fingers are cellular immediate early genes which are rapidly and transiently expressed after stimulation with a variety of agents. Egr-1 encodes a nuclear phosphoprotein that binds to promoters of downstream and play a key role in coordinating waves of gene expression that underlie the long-term changes in a variety of cell biological processes, including proliferation, apoptosis, and differentiation. Recent studies have shown that Egr-1 expression is altered in several types of neoplasia, compared to normal tissue. Therefore, Egr-1 seemed a biologic marker in malignant carcinoma and has potential application in cancer gene therapy. As an early growth response factor, there is elevated Egr-1 expression in hypoxic enviroment and increased cytoskeletal remodeling under acute hypoxic stress. In this paper, we want to find out the novel concept that microtubules cytoskeletal is regulated by Egr-1 under acute hypoxic stress. Main results are listed below:1. Immunostainning of A549 cell line, specimens demonstrated higher levels of Egr-1 in malignant cells located predominantly in the cytoplasm at interphase of mitosis. We can find that Egr-1 presents skeleton -like distribution. There is no rapid nuclear translocation. Western blot demonstrated that the expression of Egr-1 elevated under acute hypoxic stress.2. The cytoskeleton disassembled under the low temperature or nocodazole treatment. Hypoxic treatment kept cytoskeletal integrity and slowed down the damage of cytoskeletal structures. RNAi inhibited significantly the expression of Egr-1 in A549 cells. The cytoskeleton became abnormality and microtube seemed clump. MTT cell proliferation analysis indicated that pShuttle-H1-siRNA/Egr-1 vector could inhibit the viability of A549 cells by over 60% at 3 days of transfection. Maybe cells apoptosis leads to it.