Insulin-like growth factor 1 receptor (IGF-1R) plays many crucial roles in cancer, like anti-apoptotic activity and necessity for transformation. IGF-1R knockout cells (R-) represent a useful tool for molecular mapping of biological properties of the receptor. R- cells have been shown to be refractory to transformation by viral and cellular oncogenes, highlighting the necessity of this receptor for transformation. Surprisingly, more recent studies have shown that these cells can undergo spontaneous transformation. This observation raises the question as whether R- cells over the years have acquired some properties mimicking those of IGF-1R. Using an IGF-1R inhibitor (cyclolignan PPP) we have identified clones of R- (R-s) that are sensitive to this compound. Since, PPP is closely related to podophyllotoxin, which is an efficient microtubule inhibitor, we first investigated if such a mechanism could explain the sensitivity to PPP. However, highly purified PPP showed no or very slight tubulin binding. Further analysis of R-s revealed expression of a 90 kDa protein being reactive to IGF-1R beta-subunit antibodies. This protein was weakly but constitutively tyrosine phosphorylated and was downregulated by siRNA targeting IGF-1R. This downregulation was paralleled by decreased R-s survival. Taken together, our study suggests that clones of R- express IGF-1R activity and dependency, which in turn may explain that R- can undergo spontaneous transformation.
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http://dx.doi.org/10.1016/j.bbrc.2006.07.006 | DOI Listing |
Biofactors
January 2025
Department of Biological Science and Technology, College of Life Sciences, China Medical University, Taichung, Taiwan, ROC.
Ultraviolet (UV) irradiation is a major factor contributing to skin photoaging, including the formation of reactive oxygen species (ROS), collagen breakdown, and overall skin damage. Insulin-like growth factor-I (IGF-1) is a polypeptide hormone that regulates dermal survival and collagen synthesis. Echinacoside (Ech), a natural phenylethanoid glycoside, is the most abundant active compound in Cistanches.
View Article and Find Full Text PDFActa Neurol Belg
January 2025
Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, 124001, Haryana, India.
Insulin resistance is a condition characterized by the attenuated biological response in the presence of normal or elevated insulin level and therefore is characterized by the impaired sensitivity to insulin and impaired glucose disposal and utilization. Insulin resistance in brain/Brain insulin resistance (BIR) is accompanied by the various manifestations including alteration in glucose sensing by hypothalamic neurons, impaired sympathetic outflow in response to hypoglycemia, increased ROS production, impaired mitochondrial oxygen consumption in the brain, cognitive deficits and neuronal cell damage. It has been reported that the disrupted insulin signaling is accompanied by the reduced expression of insulin receptor (IR)/insulin receptor substrate 1 (IRS1)/PI3K/AKT and IGF-1 receptor (IGF-1R)/IRS2/PI3K pathways.
View Article and Find Full Text PDFEur J Pharmacol
January 2025
Academy of Integrated Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China. Electronic address:
Dihydrotanshinone I (DHT) is an active ingredient derived from Salvia miltiorrhiza. Previous studies have demonstrated that DHT can improve cardiac function in rats with myocardial ischemia-reperfusion injury (IR). However, the mechanism by which DHT improves myocardial injury in rats still requires further research.
View Article and Find Full Text PDFNat Commun
January 2025
Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, UK.
During recent decades, changes in lifestyle have led to widespread nutritional obesity and its related complications. Remodelling adipose tissue as a therapeutic goal for obesity and its complications has attracted much attention and continues to be actively explored. The endothelium lines all blood vessels and is close to all cells, including adipocytes.
View Article and Find Full Text PDFInt Immunopharmacol
January 2025
Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China. Electronic address:
RNA-binding motif 47 (RBM47) is a recently identified RNA-binding protein involved in early vertebrate development, immune homeostasis, and cancer development. This study examined the biological functions of RBM47 in thyroid-associated ophthalmopathy (TAO). Orbital fibroblasts (OFs) were obtained from the control (n = 6) and TAO groups (n = 6).
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