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.
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.
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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. · 2.08 Impact Factor
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ABSTRACT: Erlotinib and pemetrexed have been approved for the second-line treatment of non-small cell lung cancer (NSCLC). These two agents have different mechanisms of action. Combined treatment with erlotinib and pemetrexed could potentially augment the antitumor activity of either agent alone. In the present study, we investigated the safety profile of combined administration of the two agents in pretreated NSCLC patients. A phase I dose-finding study (Trial registration: UMIN000002900) was performed in patients with stage III/IV nonsquamous NSCLC whose disease had progressed on or after receiving first-line chemotherapy. Patients received 500 mg/m2 of pemetrexed intravenously every 21 days and erlotinib (100 mg at Level 1 and 150 mg at Level 2) orally on days 2-16. Twelve patients, nine males and three females, were recruited. Patient characteristics included a median age of 66 years (range, 48-78 years), stage IV disease (nine cases), adenocarcinoma (seven cases) and activating mutation-positives in the epidermal growth factor receptor gene (two cases). Treatment was well-tolerated, and the recommended dose of erlotinib was fixed at 150 mg. Dose-limiting toxicities were experienced in three patients and included: grade 3 elevation of serum alanine aminotransferase, repetitive grade 4 neutropenia that required reduction of the second dose of pemetrexed and grade 3 diarrhea. No patient experienced drug-induced interstitial lung disease. Three patients achieved a partial response and stable disease was maintained in five patients. Combination chemotherapy of intermittent erlotinib with pemetrexed was well-tolerated, with promising efficacy against pretreated advanced nonsquamous NSCLC.BMC Cancer 07/2012; 12:296. · 3.33 Impact Factor
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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; · 2.91 Impact Factor