Selective Epidermal Growth Factor Receptor Tyrosine Kinase Research Articles

Icotinib, a selective EGF receptor tyrosine kinase inhibitor, for the treatment of non-small-cell lung cancer.

Advanced non-small-cell lung cancer (NSCLC) is the main cause for cancer-related mortality. Treatments for advanced NSCLC are largely palliative and a benefit plateau appears to have reached with the platinum-based chemotherapy regimens. EGF receptor (EGFR) tyrosine kinase inhibitors gefitinib, erlotinib and afatinib came up with prolonged progression-free survival and improved quality of life, especially in EGFR-mutated patients. Icotinib is an oral selective EGFR tyrosine kinase, which was approved by China Food and Drug administration in June 2011 for treating advanced NSCLC. Its approval was based on the registered Phase III trial (ICOGEN), which showed icotinib is noninferior to gefitinib. This review will discuss the role of icotinib in NSCLC, and its potential application and ongoing investigations.

Emerging Strategies to Strengthen the Anti-Tumour Activity of Type I Interferons: Overcoming Survival Pathways

Interferon-a (IFN-a) is currently the most used cytokine in the treatment of cancer. However, the potential anti-tumour activity of IFN-a is limited by the activation of tumour resistance mechanisms. In this regard, we have shown that IFN-a, at growth inhibitory concentrations, enhances the EGF-dependent Ras-->Erk signalling and decreases the adenylate cyclase/cAMP pathway activity in cancer cells; both effects represent escape mechanisms to the growth inhibition and apoptosis induced by IFN-a. The selective targeting of these survival pathways might enhance the antitumor activity of IFN-ain cancer cells, as shown by: i) the combination of selective EGF receptor tyrosine kinase inhibitor (gefitinib) and IFN-a having cooperative anti-tumour effects; ii) the farnesyl-transferase inhibitor R115777 strongly potentiating the anti-tumour activity of IFN-a both in vitro and in vivo through the inhibition of different escape mechanisms that are dependent on isoprenylation of intracellular proteins such as ras; iii) the cAMP reconstituting agent (8-Br-cAMP) enhancing the pro-apoptotic activity of IFN-alpha. IFN-beta is a multifunctional cytokine binding the same receptor of IFN-alpha, but with higher affinity (10-fold) and differential structural interactions. We recently showed that IFN-beta is considerably more potent than IFN-alpha in its anti-tumour effect through the induction of apoptosis and/or cell cycle arrest in S-phase. The emergence of long-acting pegylated forms of IFN-beta makes this agent a promising anti-cancer drug. These observations open a new scenario of anticancer intervention able to strengthen the antitumor activity of IFN-alpha or to use more potent type I IFNs.

Expression of epidermal growth-factor receptor in lymphangiomatosis: a new therapeutic target?

Lymphangiomatosis is a rare disease characterised by multiple, infiltrative proliferations of lymphatic endothelium in the mediastinum and other somatic or visceral sites. Surgical resection, chemotherapy, and radiotherapy are all used to treat this disorder but have limited effectiveness. We have characterised the morphological and functional endothelial properties of the lymphatic tissue of one patient with mediastinal lymphangiomatosis and identified two morphologically and functionally different types of lymphatic endothelial cell (LECI and LECII). The morphology and cellular function of LECI cells resembled vascular endothelial cells and lymphatic tissues of healthy individuals (figure A; stained with an antibody against epidermal growth-factor [EGF] receptor). LECII cells, however, had increased proliferation and an altered immunohistochemical appearance—in particular, pronounced expression of CD31 and EGF-receptor (figure B; stained with an antibody against EGF-receptor). Increased expression of CD31 in LECII cells suggests they can be targeted with non-specific antiangiogenetic agents such as interferons or vascular endothelial growth-factor inhibitors. Furthermore, increased expression of EGF-receptors in LECII cells could provide a therapeutic target for selective EGF-receptor tyrosine-kinase inhibitors. These data show that mediastinal lymphangiomatosis is associated with an aberrant lymphatic endothelial cell-type that has targetable characteristics allowing for disease-specific pharmacological intervention.

Regulation of prostaglandin H synthase-2 expression in cerebromicrovascular smooth muscle by serum and epidermal growth factor.

Growth factors may play a role in the formation of prostaglandins (PG) by cerebral blood vessels during development or reaction to injury. In smooth muscle cultures isolated from murine cerebral microvessels PG production was induced with either serum or epidermal growth factor (EGF). Prostaglandin H synthase (PGHS) activity peaked at 6 h after the addition of 10% serum or 50 ng/ml EGF. Increases in expression of PGHS-1 mRNA were small (7- to 10-fold) compared with PGHS-2 (30- to 120-fold), and the induction patterns were different for serum and EGF. An increase in PGHS-2 message was detected by 0.5 h of adding either agent, but peak induction occurred earlier for EGF than for serum, 1 h vs. 3 h, respectively. The response to either stimulus had returned to prestimulation levels by 12 h. The induction of PGHS-2 protein was also transient, but followed a more delayed time course (peak levels at 6 h). Induction of activity, message, and protein by either agent was blocked by 1 microM dexamethasone and attenuated by genistein (100 microM), a nonspecific tyrosine kinase inhibitor. Tyrphostin 47, a more selective EGF receptor tyrosine kinase inhibitor, dose-dependently inhibited EGF-stimulated PGHS activity, completely abolishing PG production at 100 microM. However, this inhibitor had no effect on serum-stimulated PG production. Curiously, 100 microM tyrphostin 47 enhanced EGF-induced PGHS-2 mRNA and protein expression. These data suggest that EGF induces the expression of PGHS-2 in cerebromicrovascular smooth muscle by a mechanism that requires tyrosine kinase activity and that is distinct from serum.

Synthesis of [methoxy-11C]PD153035, a selective EGF receptor tyrosine kinase inhibitor

[Methoxy- 11 C]PD153035, a potent and specific inhibitor of the EGF receptor tyrosine kinase, was prepared by O-alkylation of O-desmethyl PD153035 with [ 11 C]methyl iodide in DMF. The radiochemical incorporation of [ 11 C]CH 3 I was on the order of 45%. The mean specific activity obtained at end-of-synthesis (EOS) was 26 GBq/μmol (n=3; range 20-36 GBq/μmol) and total synthesis time was 45-50 minutes including formulation.