Epidermal growth factor receptor kinase domain mutations are rare in salivary gland carcinomas

Activating mutations within the epidermal growth factor (EGFR) tyrosine kinase domain identify non-small cell lung cancer patients with improved clinical response to tyrosine kinase inhibitor therapy. Recently, we identified two EGFR mutations in a cohort of 25 salivary gland carcinomas (SGCs) by screening the tumour samples for the both most common hotspot mutations in exons 19 and 21 by allele-specific PCR. Here, we present a comprehensive sequencing analysis of the entire critical EGFR tyrosine kinase domain in 65 SGC of the main histopathological types. We found EGFR mutations in the tyrosine kinase domain to be a rare event in SGCs. No additional mutations other than the two known exon 19 deletions (c.2235_2249del15) in a mucoepidermoid carcinoma and an adenoid cystic carcinoma have been detected. Other putative predictive markers for EGFR-targeted therapy in SGCs might be relevant and should be investigated

Indomethacin induces apoptosis via a MRP1-dependent mechanism in doxorubicin-resistant small-cell lung cancer cells overexpressing MRP1

Small-cell lung cancers (SCLCs) initially respond to chemotherapy, but are often resistant at recurrence. The non-steroidal anti-inflammatory drug indomethacin is an inhibitor of multidrug resistance protein 1 (MRP1) function. The doxorubicin-resistant MRP1-overexpressing human SCLC cell line GLC4-Adr was highly sensitive for indomethacin compared with the parental doxorubicin-sensitive line GLC4. The purpose of this study was to analyse the relationship between hypersensitivity to indomethacin and MRP1 overexpression. The experimental design involved analysis of the effect of MRP1 downregulation on indomethacin-induced cell survival and apoptosis in GLC4-Adr and GLC4, using siRNA. In addition the effect of indomethacin on glutathione levels and mitochondrial membrane potential was investigated. Small interfering RNAs directed against MRP1 reduced MRP1 mRNA levels twofold and reduced efflux pump function of MRP1, which was reflected by a 1.8-fold higher accumulation of MRP1 substrate carboxyfluorescein, in si-MRP1 versus si-Luciferase-transfected GLC4-Adr cells. Multidrug resistance protein 1 downregulation decreased initial high apoptosis levels 2-fold in GLC4-Adr after indomethacin treatment for 24 h, and increased cell survival (IC50) from 22.8±2.6 to 30.4±5.1 μM following continuous indomethacin exposure. Multidrug resistance protein 1 downregulation had no effect on apoptosis in GLC4 or on glutathione levels in both lines. Although indomethacin (20 μM) for 2 h decreased glutathione levels by 31.5% in GLC4-Adr, complete depletion of cellular glutathione by L-buthionine (S,R)-sulphoximine only resulted in a small increase in indomethacin-induced apoptosis in GLC4-Adr, demonstrating that a reduced cellular glutathione level is not the primary cause of indomethacin-induced apoptosis. Indomethacin exposure decreased mitochondrial membrane potential in GLC4-Adr cells, suggesting activation of the mitochondrial apoptosis pathway. Indomethacin induces apoptosis in a doxorubicin-resistant SCLC cell line through an MRP1-dependent mechanism. This may have implications for the treatment of patients with MRP1-overexpressing tumours

Multi-Target Drugs: The Trend of Drug Research and Development

Summarizing the status of drugs in the market and examining the trend of drug research and development is important in drug discovery. In this study, we compared the drug targets and the market sales of the new molecular entities approved by the U.S. Food and Drug Administration from January 2000 to December 2009. Two networks, namely, the target–target and drug–drug networks, have been set up using the network analysis tools. The multi-target drugs have much more potential, as shown by the network visualization and the market trends. We discussed the possible reasons and proposed the rational strategies for drug research and development in the future

Indomethacin-induced activation of the death receptor-mediated apoptosis pathway circumvents acquired doxorubicin resistance in SCLC cells

Small-cell lung cancers (SCLCs) initially respond to chemotherapy but are often resistant at recurrence. A potentially new method to overcome resistance is to combine classical chemotherapeutic drugs with apoptosis induction via tumour necrosis factor (TNF) death receptor family members such as Fas. The doxorubicin-resistant human SCLC cell line GLC(4)-Adr and its parental doxorubicin-sensitive line GLC(4) were used to analyse the potential of the Fas-mediated apoptotic pathway and the mitochondrial apoptotic pathway to modulate doxorubicin resistance in SCLC. Western blotting showed that all proteins necessary for death-inducing signalling complex formation and several inhibitors of apoptosis were expressed in both lines. The proapototic proteins Bid and caspase-8, however, were higher expressed in GLC(4)-Adr. In addition, GLC(4)-Adr expressed more Fas (3.1x) at the cell membrane. Both lines were resistant to anti-Fas antibody, but plus the protein synthesis inhibitor cycloheximide anti-Fas antibody induced 40% apoptosis in GLC(4)-Adr. Indomethacin, which targets the mitochondrial apoptotic pathway, induced apoptosis in GLC(4)-Adr but not in GLC(4) cells. Surprisingly, in GLC(4)-Adr indomethacin induced caspase-8 and caspase-9 activation as well as Bid cleavage, while both caspase-8 and caspase-9 specific inhibitors blocked indomethacin-induced apoptosis. In GLC(4)-Adr, doxorubicin plus indomethacin resulted in elevated caspase activity and a 2.7-fold enhanced sensitivity to doxorubicin. In contrast, no effect of indomethacin on doxorubicin sensitivity was observed in GLC(4). Our findings show that indomethacin increases the cytotoxic activity of doxorubicin in a doxorubicin-resistant SCLC cell line partly via the death receptor apoptosis pathway, independent of Fas

Effect of Deltoid Ligament Repair versus Syndesmosis Fixation on Ankle Joint Stability After Bimalleolar Equivalent Ankle Fracture

Category: Trauma Introduction/Purpose: The current standard for stabilization of the talus within the ankle mortise after bimalleolar equivalent ankle fracture is open reduction and internal fixation (ORIF) of the lateral malleolus followed by syndesmotic screw fixation of the syndesmosis. Syndesmotic fixation may be associated with complications such as mal-reduction, joint stiffness, altered ankle biomechanics, and potential additional surgery for hardware removal. Consequently, some surgeons advocate ORIF of the lateral malleolus in conjunction with deltoid ligament repair rather than syndesmosis fixation. To our knowledge, clinical reports of this treatment option lack biomechanical evidence to support this approach. The purpose of this investigation was to compare ankle joint stability and contact pressures in a bimalleolar equivalent ankle fracture model treated with trans-syndesmotic screw fixation versus deltoid ligament repair. Methods: We prepared and tested seven fresh frozen cadaveric whole lower leg specimens with an undisturbed proximal tibiofibular joint. We tested each leg was tested under five conditions: (1) intact, (2) syndesmosis disrupted and deltoid ligament sectioned, (3) syndesmosis reduced w/ screw fixation, (4) deltoid repaired, and (5) both syndesmosis and deltoid ligament repaired. Under a nominal axial load, we applied controlled anterior, posterior, lateral, and medial drawer stresses to the foot using a custom-built testing apparatus and documented the resulting talar translation relative to the tibia. We also applied controlled internal and external rotation stresses to the ankle model and measured the provoked ankle joint rotations. In each condition, we measured peak ankle contact pressure (PACP) using a Tekscan pressure sensor under a physiologic axial load simulating single-limb stance. Results: Concurrent disruption of the syndesmosis and the deltoid ligament significantly (p<.05) increased anterior drawer, lateral drawer, and internal and external rotation. Subsequent deltoid repair significantly reduced anterior displacement to normal levels, but syndesmosis fixation did not. Lateral drawer was not significantly corrected until both deltoid ligament and syndesmosis were repaired. Deltoid repair and syndesmosis fixation each reduced internal rotation significantly, with further reduction to normal levels when both were repaired. External rotation remained elevated relative to the intact condition regardless of which structures were repaired. Deltoid repair and syndesmosis fixation achieved similar levels of posterior, lateral and medial drawer reduction, but these measures did not approach normal values until both were repaired. No significant differences in PACP were identified among the five tested conditions. Conclusion: Isolated repair of the deltoid ligament after a bimalleolar equivalent ankle fracture achieves markedly better anterior displacement stability than does fixation of the syndesmosis with a screw. Under the described testing conditions, the two procedures offer similar posterior, medial, and lateral talar displacement stability and similar levels of internal and external rotational stability. Given the complications that may be associated with rigid syndesmotic screw fixation, our investigation suggests that deltoid repair may represent a reasonable alternative to syndesmosis fixation