logo
    The Role of Epidermal Growth Factor Receptor Mutations and Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors in the Treatment of Lung Cancer
    6
    Citation
    58
    Reference
    10
    Related Paper
    Citation Trend
    Abstract:
    Lung cancer is the leading cause of cancer-related deaths worldwide. Non-small-cell lung cancer (NSCLC) cases comprise approximately 85% of the lung cancer cases. Before the era of target therapy, platinum-based doublet chemotherapy only led to a median survival of 8-9 months and a one-year survival of 30%-40% in patients with advanced NSCLC. In July 2002, gefitinib, a small-molecule epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), was approved for the treatment of patients with advanced NSCLC in Japan. After the widespread use of gefitinib in the treatment of NSCLC, there have been many new studies regarding the association between the clinical anticancer efficacy of gefitinib and the somatic EGFR mutation status in patients with NSCLC. This article summarizes the role of EGFR mutations in lung cancer and the use of EGFR antagonists in the treatment of lung cancer and its associated adverse effects.
    Novel concepts and understanding of receptors lead to discoveries and optimization of many small molecules and antibodies as anti-cancerous drugs.Receptor tyrosine kinases (RTKs) are such a promising class of receptors under the investigation in past three decades.RTKs are one of the essential mediators of cell signaling mechanism for various cellular processes.Transformations such as overexpression, dysregulation, or mutations of RTKs may result into malignancy, and thus are an important target for anticancer therapy.Numerous subfamilies of RTKs, such as epidermal growth factor receptor, vascular endothelial growth factor receptor, fibroblast growth factor receptors, insulin-like growth factor receptor, and hepatocyte growth factor receptor, have been being investigated in recent years as target for anticancer therapy.The present review focuses several small molecules drugs as well as monoclonal antibodies targeting aforesaid subfamilies either approved or under investigation to treat the various cancers.
    Receptor Protein-Tyrosine Kinases
    Targeted Therapy
    PC12 cells possess specific receptors for both nerve growth factor and epidermal growth factor, and by an unknown mechanism, nerve growth factor is able to attenuate the propagation of a mitogenic response to epidermal growth factor. The differentiation response of PC12 cells to nerve growth factor, therefore, predominates over the proliferative response to epidermal growth factor. We have observed that the addition of nerve growth factor to PC12 cells rapidly produces a decrease in surface 125I-epidermal growth factor binding capacity. Unlike previously described nerve growth factor effects on 125I-epidermal growth factor binding capacity, which required several days of nerve growth factor exposure, the decreases we report occur within minutes of nerve growth factor addition: A 50% decrease in 125I-epidermal growth factor binding capacity is evident at 10 min. This rapid nerve growth factor response is concentration dependent; inhibition of 125I-epidermal growth factor binding is detectable at nerve growth factor levels as low as 0.2 ng/ml and is maximal at approximately 50 ng/ml, consistent with known ranges of biological activity. No demonstrable differences in the rate of epidermal growth factor receptor synthesis or degradation were observed in cells acutely exposed to nerve growth factor. Scatchard analysis revealed that acute nerve growth factor treatment decreased the number of both high- and low-affinity 125I-epidermal growth factor binding sites, while the receptor affinity remained unchanged. We have also investigated the involvement of various potential intracellular mediators of nerve growth factor action and of known intracellular modulatory systems of the epidermal growth factor receptor for their capacity to participate in this nerve growth factor activity.
    Tyrosine kinase receptors are proteins that transduce the signal from many growth factor and cytokine ligands to produce intracellular responses. As such they can activate multiple signalling cascade pathways and influence cell division, migration and survival. Many show upregulation in certain malignancies, including those of the gastrointestinal tract, and are thought to play key roles in carcinogenesis. This makes them attractive targets for drug therapy and in recent years many inhibitors have been developed. This review discusses the current situation regarding the development of inhibitors with particular reference to the erbB family, the insulin-like growth factor receptor, the Met receptor, the receptor for vascular endothelial growth factor and the Kit receptor. The evidence will be related back to cancers of the gut lumen. Clinical effectiveness in this area seems to lie in using a combinatorial approach that inhibits multiple key signalling points, and the reasons for this will be discussed.
    ROR1
    Citations (1)
    We studied the regulation of the epidermal growth factor receptor mRNA and the number of epidermal growth factor binding sites in subcellular compartments involved in the biosynthesis and endocytosis of the epidermal growth factor receptor during the prereplicative phase of liver regeneration. The epidermal growth factor receptor mRNA, quantified by solution hybridization, decreased after partial hepatectomy, with a nadir of about 35% 18 hr after hepatectomy. An even strongèr decrease in the number of epidermal growth factor binding sites after partial hepatectomy was observed in a Golgi-enriched low-density membrane fraction, reflecting available newly synthesized epidermal growth factor receptors. It is suggested that this decrease in newly synthesized available epidermal growth factor receptors is caused primarily, but not entirely, by decreased epidermal growth factor receptor mRNA levels and the additional downregulation of epidermal growth factor binding sites may involve posttranslational mechanisms such as intracellular occupation by transforming growth factor-α. The observation that the number of specific epidermal growth factor binding sites after partial hepatectomy was only moderately reduced in prelysosomal endosomes and in lysosomes, compared with the newly synthesized receptors, may indicate that a pool of receptors targeted for lysosomes exists and these receptors are regulated in a different manner than the receptor pool targeted for the cell surface. Furthermore, at least two separable endocytic subcompartments are involved in the transport of the epidermal growth factor/epidermal growth factor receptor complex in the liver. The complex first enters early endosomes, then enters late, prelysosomal endosomes, where the epidermal growth factor is proteolytically processed, before arriving in the lysosomal compartment. (Hepatology 1990;12:533-541).
    Liver Regeneration
    Citations (19)
    PC12 cells, which differentiate morphologically and biochemically into sympathetic neruonlike cells in response to nerve growth fact, also respond to epidermal growth factor. The response to epidermal growth factor is similar in certain respects to the response to nerve growth fact. Both peptides produce rapid increases in cellular adhesion and 2-deoxyglucose uptake and both induce ornithine decarboxylase. But nerve growth factor causes a decreased cell proliferation and a marked hypertrophy of the cells. In contrast, epidermal growth factor enhances cell proliferation and does not cause hypertrophy. Nerve growth factor induces the formation of neuritis; epidermal growth factor does not. When both factors are presented simultaneously, the cells form neurites. Furthermore, the biological response to epidermal growth fact, as exemplified by the induction of ornithine decarboxylase, is attenuated by prior treatment of the cells with nerve growth factor. PC12 cells have epidermal growth factor receptors. The binding of epidermal growth factor to these receptors is rapid and specific, and exhibits an equilibrium constant of 1.9 x 10(-9) M. Approximately 80,000 receptors are present per cell, and this number is independent of cell density. Treatment of the cells with nerve growth factor reduces the amount of epidermal growth factor binding by at least 80 percent. The decrease in receptor binding begins after approximately 12-18 h of nerve growth factor treatment and is complete within 3 d. Scratchard plots indicate that the number of binding sites decreases, not the affinity of the binding sites for epidermal growth factor.
    Citations (262)
    The dependence of tumor growth on the development of a neovasculature is well established. One of the best studied angiogenic factor is vascular endothelial growth factor (VEGF). VEGF belongs to a family of homodimeric glycoproteins that bind to three different VEGF receptor (VEGFR) tyrosine kinases in an overlapping pattern. VEGFRs share regulatory mechanisms with other well-characterized receptor tyrosine kinases, such as the platelet-derived growth factor receptor (PDGFR). These mechanisms include receptor dimerization and activation of tyrosine kinase, as well as creation of docking sites for signal transducers to direct cellular function including cell migration, survival, and proliferation. Tumor biology studies, drug development, and clinical studies have established VEGFR and PDGFR as validated drug targets. Well-interconnected preclinical and clinical efforts are necessary for the continued development of this exciting process. This chapter will review the biological role of VEGFR and PDGFR signal transduction and the interplay between the different receptors as it relates to kidney cancer.
    Platelet-derived growth factor
    Receptor Protein-Tyrosine Kinases