Article

Schedule-dependent antitumor activity of the combination with erlotinib and docetaxel in human non-small cell lung cancer cells with EGFR mutation, KRAS mutation or both wild-type EGFR and KRAS.

Product Research Department, Kamakura Research Laboratories, Chugai Pharmaceutical Co., Ltd., Kamakura, Kanagawa 247-8530, Japan.
Oncology Reports (Impact Factor: 2.19). 11/2010; 24(5):1141-6.
Source: PubMed

ABSTRACT Erlotinib is used as a standard treatment for recurrent advanced non-small cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) mutations in NSCLC have been shown to be a predictive factor of erlotinib, although the relationship between K-ras oncogene (KRAS) mutations and erlotinib resistance is controversial. Recently, in vitro sequence-dependent interactions of erlotinib and docetaxel have been studied on as a novel therapeutic approach against NSCLC. The purpose of the present study was to determine the optimum novel regimen of erlotinib and docetaxel against NSCLC cells which have EGFR mutation (HCC827 cells), KRAS mutation (A549 cells) or both wild-type (NCI-H292 cells). First, we analyzed the effects of in vitro combination for cell proliferation-inhibition using a combination index. In all cell lines, docetaxel followed by erlotinib treatment showed nearly additive effects. On the other hand, erlotinib followed by docetaxel treatment showed remarkable antagonistic interactions. Second, we examined the effect of combinations on the in vitro apoptosis induction. Erlotinib followed by docetaxel treatment reduced apoptosis induction compared with docetaxel alone; in contrast, docetaxel followed by erlotinib treatment had no inhibitory effects on docetaxel-induced apoptosis in any of the cell lines. Finally, an in vivo tumor growth inhibition test was performed using xenograft models. Docetaxel followed by erlotinib administration resulted in significant tumor growth inhibition compared with erlotinib or docetaxel monotherapy in all models. In conclusion, we demonstrated that docetaxel followed by erlotinib therapy was a potentially optimum regimen against NSCLC regardless of the mutation status of EGFR and KRAS.

0 Bookmarks
 · 
54 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The MUC1-C oncoprotein is aberrantly expressed in most multiple myeloma cells. However, the functional significance of MUC1-C expression in multiple myeloma is not known. The present studies demonstrate that treatment of multiple myeloma cells with a MUC1-C inhibitor is associated with increases in reactive oxygen species (ROS), oxidation of mitochondrial cardiolipin, and loss of the mitochondrial transmembrane potential. The MUC1-C inhibitor-induced increases in ROS were also associated with down-regulation of the p53-inducible regulator of glycolysis and apoptosis (TIGAR). In concert with the decrease in TIGAR expression, which regulates the pentose phosphate pathway, treatment with the MUC1-C inhibitor reduced production of NADPH, and in turn glutathione (GSH) levels. TIGAR protects against oxidative stress-induced apoptosis. The suppression of TIGAR and NADPH levels thus contributed to ROS-mediated late apoptosis/necrosis of multiple myeloma cells. These findings indicate that multiple myeloma cells are dependent on MUC1-C and TIGAR for maintenance of redox balance and that targeting MUC1-C activates a cascade involving TIGAR suppression that contributes to multiple myeloma cell death.
    Blood 11/2011; 119(3):810-6. · 9.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Tyrosine-kinase inhibitors (TKIs) and chemotherapy had different pharmacological mechanisms and therefore combined administration of TKIs and chemotherapy agents may have synergy. Our research aimed at exploring the cytotoxic interactions between gefitinib and docetaxel with different concentrations for non-small-cell lung cancer cell lines, and furthermore, the mechanisms underlying the cytotoxic synergism. NCI-H1650 [epidermal growth factor receptor (EGFR) mutation and KRAS wild-type], NCI-H292 (EGFR wild-type and KRAS wild-type) and A549 (EGFR wild-type and KRAS mutation) cell lines were treated with docetaxel and/or gefitinib. Cytotoxic interactions, cell cycle distribution and cell signal pathway were analyzed, respectively. Cytotoxic interactions between docetaxel and gefitinib were dose-dependent and sequence-dependent in all these three cell lines. Docetaxel followed by gefitinib treatment was optimum regimen regardless of the mutation status of EGFR and KRAS. KRAS mutation and EGFR wild-type predicted insensitive to gefitinib and docetaxel combined treatment as well as gefitinib alone. G1 arrest was inconsistently associated with combination index (CI). However, apoptosis induction was schedule-dependent and can explain the synergism completely. Mitogen-activated protein kinase (MAPK) phosphorylation ratio was also schedule-dependent and positively correlated with CI. Cytotoxic interactions between docetaxel and gefitinib were sequence-dependent regardless of the mutation status of EGFR and KRAS. Cell characteristic, apoptosis induction and MAPK phosphorylation but not cell cycle change may explain the molecular mechanisms of synergism.
    Journal of Cancer Research and Clinical Oncology 04/2014; 140(7). · 2.91 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Non-small cell lung cancer (NSCLC) expressed high levels of epidermal growth factor receptor (EGFR). Gefitinib (Iressa) has demonstrated clinical efficacy in NSCLC patients harboring EGFR mutations or refractory to chemotherapy. However, most of NSCLC patients are with wild type EGFR, and showed limited response to gefitinib. Therefore, to develop new effective therapeutic interventions for NSCLC is still required. Our previous study showed Marsdenia tenacissima extract (MTE) restored gefitinib efficacy in the resistant NSCLC cells, but whether MTE acts in the gefitinib-sensitive NSCLC cells is the same as it in the resistant one is unknown.
    BMC Complementary and Alternative Medicine 05/2014; 14(1):165. · 1.88 Impact Factor