Additive antitumour effect of the epidermal growth factor receptor tyrosine kinase inhibitor gefitinib (Iressa, ZD1839) and the antioestrogen fulvestrant (Faslodex, ICI 182,780) in breast cancer cells

A high expression level of epidermal growth factor receptor (EGFR)/HER1 has been suggested to lead to a shorter survival time and resistance to endocrine therapy in patients with breast cancer. To test the hypothesis that inhibition of the EGFR signalling pathway affects the antitumour effect of endocrine therapy, an EGFR tyrosine kinase inhibitor (EGFR-TKI), gefitinib, and an oestrogen receptor (ER) antagonist, fulvestrant, were administered to human breast cancer cells. A total of five human breast cancer cell lines were used. The effects of single or combined treatments with gefitinib and/or fulvestrant on cell growth, cell cycle progression and apoptosis were analysed. Changes in the expression levels of cyclin-dependent kinase inhibitors, p21 and p27, an antiapoptotic factor, Bcl-2, and a proapoptotic factor, Bax, were also investigated. All cell lines tested were sensitive to gefitinib (50% growth inhibitory concentration, 10-28.5 microM). Breast cancer cell lines with a high expression level of HER1 or HER2 were more sensitive to gefitinib than the others. Gefitinib induced a significant G1-S blockade in ER-positive KPL-3C cells. Gefitinib induced significant apoptosis in HER1-overexpressing MDA-MB-231 cells. Gefitinib additively increased the antitumour effect of fulvestrant in all three ER-positive cell lines in a medium supplemented with 17beta-oestradiol. The combined treatment promoted cell cycle retardation in KPL-3C cells, which is associated with an upregulation of p21 by fulvestrant and gefitinib, respectively. Apoptosis was associated with downregulation of Bcl-2 by gefitinib in MDA-MB-231 cells. These results suggest an additive interaction between the EGFR-TKI gefitinib and the antioestrogen fulvestrant in ER-positive breast cancer cells.     

Cytotoxic effects induced by a combination of cyclopamine and gefitinib, the selective hedgehog and epidermal growth factor receptor signaling inhibitors, in prostate cancer cells

Although the blockade of the hedgehog cascade by using cyclopamine has been reported to inhibit the growth of some cancer cell types, few studies on the mechanism by which this drug alone or in combination with other cytotoxic agents induces its cytotoxic effect have been reported. In our study, we evaluate, for the first time, the antiproliferative and cytotoxic effects induced by a combination of selective SMO inhibitor, cyclopamine and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, gefitinib on metastatic prostate cancer (PC) cells. The results revealed that cyclopamine, alone or at a lower concentration in combination with gefitinib, inhibited the growth of sonic hedgehog- (SHH), epidermal growth factor- (EGF) and serum-stimulated androgen-sensitive LNCaP-C33 and LNCaP-LN3 and androgen-independent LNCaP-C81, DU145 and PC3 cells. The antiproliferative effect of cyclopamine and gefitinib, alone or in combination, was mediated via a blockade of the PC3 cells in the G1 phase of the cell cycle. Importantly, the combined cyclopamine and gefitinib also caused a higher rate of apoptotic death of PC cells compared to single agents. The cytotoxic effect induced by these drugs in PC3 cells appears to be mediated at least, in part, via the mitochondrial pathway through the depolarization of the mitochondrial membrane and the release of cytochrome c and reactive oxygen species into the cytosol. This was also accompanied by the activation of caspase cascades, PARP cleavage and DNA fragmentation. Additionally, the combined cyclopamine and gefitinib were more effective at suppressing the invasiveness of PC3 cells through matrigel in vitro as the drugs alone. These findings indicate that the simultaneous blockade of SHH-GLI-1 and EGF-EGFR signaling, which results in the growth arrest and massive rate of apoptotic cell death, represents a promising strategy for a more effective treatment of metastatic PC forms.     

Activity of a specific inhibitor, gefitinib (Iressa, ZD1839), of epidermal growth factor receptor in refractory non-small-cell lung cancer.

BACKGROUND: Gefitinib (Iressa(TM), ZD1839) is an orally active, selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor. Phase I studies showed that it is well tolerated, with evidence of tumor regression in patients with advanced non-small-cell lung cancer (NSCLC). Therefore, we aimed to assess the antitumor activity and tolerability of gefitinib in a series of patients with previously treated, advanced NSCLC, as a part of a compassionate use program. PATIENTS AND METHODS: To be eligible, all patients were required to have histologically or cytologically proven advanced or metastatic NSCLC, prior chemotherapy with at least one cisplatin-containing chemotherapy regimen or contraindication to cytotoxic drugs, Eastern Cooperative Oncology Group performance status < or =2, and adequate hematological, renal and hepatic parameters. All patients provided signed informed consent. Patient re-evaluation was performed every 4-6 weeks. RESULTS: Seventy-three consecutive patients were enrolled. Response rate, including complete and partial response, was 9.6%; an additional 43.8% of patients achieved stable disease, for an overall disease control of 53.4%. EGFR1 status was evaluated by immunocytochemistry in 25 patients. According to EGFR1 immunoreactivity all responses were observed with medium/strong imunoreactivity while three out of four responses were observed in high expressive patients. Median survival for all patients was 4 months while it reached 6 months for patients with disease control. The 1-year survival rate was 13.1% for the entire series and 23.2% for patients with disease control. Non-hematological toxicity was generally mild. CONCLUSION: Gefitinib has promising activity with a good toxicity profile in patients with progressive NSCLC who have received one or two prior chemotherapy regimens. A possible relationship within response and EGFR1 expression is suggested.     

Proteomic signature corresponding to the response to gefitinib (Iressa, ZD1839), an epidermal growth factor receptor tyrosine kinase inhibitor in lung adenocarcinoma.

PURPOSE: We aimed to identify candidate proteins for tumor markers to predict the response to gefitinib treatment. EXPERIMENTAL DESIGN: We did two-dimensional difference gel electrophoresis to create the protein expression profile of lung adenocarcinoma tissues from patients who showed a different response to gefitinib treatment. We used a support vector machine algorithm to select the proteins that best distinguished 31 responders from 16 nonresponders. The prediction performance of the selected spots was validated by an external sample set, including six responders and eight nonresponders. The results were validated using specific antibodies. RESULTS: We selected nine proteins that distinguish responders from nonresponders. The predictive performance of the nine proteins was validated examining an additional six responders and eight nonresponders, resulting in positive and negative predictive values of 100% (six of six) and 87.5% (seven of eight), respectively. The differential expression of one of the nine proteins, heart-type fatty acid-binding protein, was successfully validated by ELISA. We also identified 12 proteins as a signature to distinguish tumors based on their epidermal growth factor receptor gene mutation status. CONCLUSIONS: Study of these proteins may contribute to the development of personalized therapy for lung cancer patients.     

Combined epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor and chemotherapy in non-small-cell lung cancer: Chemo-refractoriness of cells harboring sensitizing-EGFR mutations in the presence of gefitinib

Background

Combined epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) with chemotherapy is believed to be more effective in treating non-small-cell lung cancer (NSCLC) with sensitizing-EGFR mutation (SEM). This hypothesis failed to be realized clinically and needs to be examined in vitro.

Materials and methods

Using the tetrazolium colorimetric assay and classical isobole method, we investigated the combination effects of 6 gefitinib-chemotherapeutic doublets (gefitinib/cisplatin, gemcitabine, pemetrexed, paclitaxel, docetaxel, or vinorelbine) in a panel of 15 NSCLC cell lines.

Results

Upon treatment with the 6 gefitinib-chemotherapeutic doublets, the 12 cell lines that did not harbor SEM displayed a broad spectrum of group results, from obvious synergism to robust antagonism. The values of group mean combination index (mCIs) ranged from 0.769 to 1.201. In contrast, the 3 cell lines with SEM showed a tendency toward consistent antagonism to the tested doublets, impressively, with a narrow range of higher group mCIs (0.993–1.141). In the presence of gefitinib, the SEM or gefitinib-sensitive group was more chemo-refractory than the non-SEM (index of chemo-refractoriness (RI): 69.33 versus 42.67; P = 0.036) or gefitinib-resistant group (68.25 versus 40.64, P = 0.0108), respectively. The results of using the gefitinib/drug combinations with the gefitinib-sensitive non-SEM cell line H322 and the gefitinib-resistant EGFR mutant H820 shared patterns similar to those with the SEM and non-SEM cell lines, respectively.

Conclusion

Gefitinib-treated EGFR-TKI-sensitive NSCLC cells showed a wide spectrum of chemo-refractoriness, suggesting that concomitantly combined EGFR-TKI-chemotherapy might not be a good treatment strategy for NSCLC harboring SEM.     

'Targeting' the epidermal growth factor receptor tyrosine kinase with gefitinib (Iressa) in non-small cell lung cancer (NSCLC)

Gefitinib (ZD1839, Iressa), a selective drug inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase (TK), was recently approved for the treatment of patients with advanced non-small cell lung cancer (NSCLC). This article reviews the identification of EGFR as a therapeutic target and the steps in the development of gefitinib as "targeted" monotherapy for patients with NSCLC. Whether EGFR is required for the maintenance of lung tumor survival is also discussed. Finally, strategies to identify predictors of response to gefitinib are explored.     

The next generation of epidermal growth factor receptor tyrosine kinase inhibitors in the treatment of lung cancer

The discovery of “driver” genomic alterations in patients with non‐small cell lung cancer (NSCLC) has dramatically changed the field of thoracic oncology in recent years. The best understood of these molecular drivers are those involving the epidermal growth factor receptor (EGFR), which when aberrantly activated are integral to the development of a subset of NSCLC tumors. First‐generation and second‐generation tyrosine kinase inhibitors (TKIs) specific to the activated EGFR have shown significant efficacy and have brought about the era of targeted therapy for NSCLC. The most common resistance mechanism is a threonine‐to‐methionine substitution (T790M) in exon 20 of the EGFR gene. Although the previous standard of care in patients with EGFR‐mutated NSCLC that progressed on initial TKI therapy was chemotherapy, third‐generation EGFR TKIs have now been developed and have yielded promising results for this population of patients with NSCLC. This article reviews the emerging data regarding third‐generation agents in the treatment of patients with advanced NSCLC. Cancer 2015;121:E1–E6. © 2014 American Cancer Society.     

Inhibition of growth factor production and angiogenesis in human cancer cells by ZD1839 (Iressa), a selective epidermal growth factor receptor tyrosine kinase inhibitor.

The transforming growth factor-alpha/epidermal growth factor receptor (TGF-alpha-EGFR) autocrine pathway, which is involved in the development and the progression of human epithelial cancers, controls, in part, the production of angiogenic factors. These angiogenic factors, including vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), are secreted by cancer cells to stimulate normal endothelial cell growth through paracrine mechanisms. ZD1839 (Iressa) is a p.o.-active, selective EGFR-tyrosine kinase inhibitor (TKI) in clinical trials in cancer patients. In this study, we evaluated the antiangiogenic and antitumor activity of ZD1839 in human colon (GEO, SW480, and CaCo2), breast (ZR-75-1 and MCF-7 ADR), ovarian (OVCAR-3), and gastric (KATO III and N87) cancer cells that coexpress TGF-alpha and EGFR. ZD1839 treatment determined a dose- and time-dependent growth inhibition accompanied by the decrease of VEGF, bFGF and TGF-alpha production in vitro. Treatment of immunodeficient mice bearing well-established, palpable GEO xenografts with ZD1839 determined a cytostatic dose-dependent tumor growth inhibition. Immunohistochemical analysis of GEO tumor xenografts after ZD1839 treatment revealed a significant dose-dependent reduction of TGF-alpha, bFGF, and VEGF expression in cancer cells and of neoangiogenesis, as determined by microvessel count. Furthermore, the antitumor activity of ZD1839 was potentiated in combination with the cytotoxic drug paclitaxel in GEO tumor xenografts. Tumor regression was observed in all mice after treatment with ZD1839 plus paclitaxel, and it was accompanied by a significant potentiation in inhibition of TGF-alpha, VEGF, and bFGF expression with a few or no microvessels. Furthermore, 6 of 16 mice bearing well-established, palpable GEO xenografts had no histological evidence of GEO tumors at the end of treatment with ZD1839 plus paclitaxel. These results demonstrate that the antitumor effect of ZD1839 is accompanied by inhibition in the production of autocrine and paracrine growth factors that sustain autonomous local growth and facilitate angiogenesis, and that this effect can be potentiated by the combined treatment with certain cytotoxic drugs, such as paclitaxel.     

Synergistic antitumor activity of epidermal growth factor receptor tyrosine kinase inhibitor gefitinib and IFN-alpha in head and neck cancer cells in vitro and in vivo.

PURPOSE: Epidermal growth factor receptor (EGFR) overexpression has been implicated in the development of head and neck squamous cell carcinomas (HNSCC) and represents a potential therapeutic target for this disease. We have reported previously that growth inhibitory concentrations of IFN-alpha enhance the expression and activity of EGFR and that this effect could represent an escape mechanism to the growth inhibition and apoptotic cell death induced by IFN-alpha. In this study, we investigate whether the combination of IFN-alpha and gefitinib (Iressa, AstraZeneca Pharmaceuticals, Macclesfield, United Kingdom), a selective EGFR tyrosine kinase inhibitor, might have a cooperative antitumor effect on HNSCC-derived cell lines. EXPERIMENTAL DESIGN: The interaction of IFN-alpha and gefitinib was evaluated in vitro on HNSCC-derived cell lines by median drug effect analysis calculating a combination index with CalcuSyn software and in vivo by using HNSCC xenografts in nude mice. The mechanism of gefitinib and IFN-alpha interactions was also studied by analysis of cell cycle kinetics, apoptosis assays, and Western blotting of EGFR signal transduction components. RESULTS: Simultaneous exposure to gefitinib and IFN-alpha produced synergistic antiproliferative and proapoptotic effects compared with single drug treatment. Furthermore, daily treatment of gefitinib (50 mg/kg p.o.) in combination with an IFN-alpha regimen (50,000 units s.c. three times weekly) induced tumor growth delay and increased survival rate on established HNSCC xenografts in nude mice. Moreover, the concomitant treatment with gefitinib suppressed the stimulation of extracellular signal-regulated kinase phosphorylation/activity induced by IFN-alpha both in vitro and in vivo. CONCLUSION: The observed cooperative antitumor effects could be, at least in part, explained by the inhibition exerted by gefitinib of an IFN-alpha-induced EGF-dependent survival pathway, which involves extracellular signal-regulated kinase activation. These results provide a rationale for the clinical evaluation of gefitinib in combination with IFN-alpha in HNSCC.     

雄激素受体在前列腺癌细胞中作用及其靶向治疗的研究进展

雄激素受体(androgen receptor, AR)在前列腺癌的发生发展中扮演重要角色。雄激素剥夺疗法(androgen deprivationtherapy, ADT)早期可成功抑制肿瘤的生长, 但最终导致肿瘤复发并进入激素抵抗阶段。AR对前列腺癌基质细胞起促进肿瘤增殖和转移作用, 是上皮腔样细胞的存活因子, 而对肿瘤干细胞样细胞及上皮基底细胞的增殖起抑制作用, AR在不同类型细胞中的不同作用向当前ADT传统的疗法提出挑战, 为发展新的治疗策略提供理论依据。目前以AR为靶点的靶向治疗药物研发也取得一些进展。本文就AR在前列腺癌不同类型细胞中的作用及靶向治疗方面的进展加以综述。      

Differential radiosensitisation by ZD1839 (Iressa), a highly selective epidermal growth factor receptor tyrosine kinase inhibitor in two related bladder cancer cell lines

The epidermal growth factor receptor (EGFR) is expressed in a wide variety of epithelial tumours including carcinoma of the bladder. Stimulation of the EGFR pathway is blocked by ZD1839 (Iressa), a highly selective EGFR tyrosine kinase inhibitor. Radical radiotherapy is an established organ sparing treatment option for muscle invasive bladder cancer and this study has explored the possibility for the use of ZD1839 as a radiosensitiser in this scenario. The effect of combination treatment with ZD1839 (0.01 microM) and ionising radiation in the established bladder cancer cell lines MGH-U1 and its radiosensitive mutant clone S40b was measured by clonogenic assays. A highly significant radiosensitising effect was seen in both cell lines (P < 0.001 for MGH-U1 and S40b cell lines). This effect was independent of the concentration of the drug and the duration of exposure prior to treatment with ionising radiation. Cell cycle kinetics of both cell lines was not significantly altered with ZD1839 (0.01 microM) as a single agent. A modest induction of apoptosis was observed with ZD1839 (0.01 microM) as a single agent, but a marked induction was observed with the combination treatment of ZD1839 and ionising radiation. These results suggest a potentially important role for ZD1839 in combination with radiotherapy in the treatment of muscle invasive bladder cancer.     

Clinical characteristics and response to tyrosine kinase inhibitors of patients with non-small cell lung cancer harboring uncommon epidermal growth factor receptor mutations

Objective:To investigate the clinical features of patients with non-small cell lung cancer (NSCLC) harboring uncommon epidermal growth factor receptor (EGFR) mutations,and the treatment outcomes of EGFR tyrosine kinase inhibitors (TKIs) in these patients.Methods:We retrospectively analyzed the data of 128 NSCLC patients pathologically diagnosed with uncommon EGFR mutation in the Department of Pathology,National Cancer Center/Cancer Hospital,Chinese Academy of Medical Sciences & Peking Union Medical College and Beijing Hospital from January 2010 to December 2015,including 40 advanced patients who received EGFR-TKI.Results:Among the total 128 patients,11 patients were non-adenocarcinoma,including squamous carcinoma (3.9％),adenosquamous carcinoma (2.3 ％),large cell carcinoma (0.8％),and composite neuroendocrine carcinoma (1.6％).Single mutations accounted for 75.0％ (96/128),including G719X (29.7％),S768I (18.0％),20 exon insertion (13.3％),L861Q (12.5％),De novo T790M (0.8％),and T725 (0.8％).Thirty-two patients harbored complex mutations.Forty advanced patients received EGFR-TKI,the objective response rate (ORR) was 20.0％,the disease control rate (DCR) was 85.0％,and the progression-free survival (PFS) was 6.4 [95％ confidence interval (95％ CI),4.8-7.9] months.The exploratory analysis of tumor response and PFS in 33 patients with G719X/S768I/L861Q subtypes showed that ORR was 21.2％ (7/33),the DCR was 93.9％ (31/33),and PFS was 7.6 (95％ CI,5.8-9.4) months.Patients with exon 20 insertion mutation and De novo T790M experienced rapid disease progression with PFS no more than 2.7 months.Conclusions:Uncommon EGFR-mutant NSCLCs are heterogeneous,EGFR-TKIs can have different efficacy in this specific subtype,and thus further individual assessment is required for each case.     

Receptor tyrosine kinase recepteur d'origine nantais as predictive marker for aggressive prostate cancer in African Americans

Published evidence shows a correlation between several molecular markers and prostate cancer (PCa) progression including in African Americans (AAs) who are disproportionately affected. Our early detection efforts led to the identification of elevated levels of antiapoptotic protein, c‐FLIP and its upstream regulatory factors such as androgen receptor (AR), recepteur d'origine nantais (RON), a receptor tyrosine kinase in human prostate tumors. The primary objective of this study was to explore whether these markers play a role in racial disparities using immunohistochemistry in prostatectomy samples from a cohort of AA, Hispanic Whites (HWs), and non‐Hispanic Whites (NHWs) . Bivariable and multivariable logistic regression analyses were used to identify a statistical association between molecular markers, possible correlation with risk factors including race, obesity, prostate‐specific antigen (PSA) and disease aggressiveness. Further, changes in the levels and expression of these molecular markers were also evaluated using human PCa cell lines. We found significantly elevated levels of RON ( P = 0.0082), AR ( P = 0.0001), c‐FLIP ( P = 0.0071) in AAs compared with HWs or NHWs. Furthermore, a higher proportion of HW and NHWs had a high Gleason score (>6) but not PSA as compared to AAs ( P = 0.032). In summary, our findings suggest that PSA was important in predicting aggressive disease for the cohort overall; however, high levels of RON may play a role in predisposing AA men to develop aggressive disease. Future research is needed using large datasets to confirm these findings and to explore whether all or any of these markers could aid in race‐specific stratification of patients for treatment.     

A human IgG-like bispecific antibody co-targeting epidermal growth factor receptor and the vascular endothelial growth factor receptor 2 for enhanced antitumor activity

Both Epidermal Growth Factor Receptor (EGFR) and the Vascular Endothelial Growth Factor Receptor 2 (VEGFR2) play critical roles in tumorigenesis. We hypothesized co-targeting EGFR and VEGFR2 using a bispecific antibody might have significant therapeutic potential. Here,we designed and produced a human IgG-like bispecific antibody (Bi-Ab) based on the variable regions of cetuximab (an anti-EGFR antibody) and mAb-04 (an anti-VEGFR2 antibody developed in our lab) . The Bi-Ab was found to inhibit the proliferation, survival and invasion of cancer cells via ablating phosphorylation of receptor and downstream signaling. In vivo efficacy was demonstrated against established HT-29 and SKOV-3 xenografts grown in nude mice. Studies revealed our Bi-Ab was able to restrain xenografted tumor growth and prolong survival of mice through inhibiting cell proliferation,promoting apoptosis and anti-angiogenesis. In contrast to cetuximab or mAb-04 alone, our Bi-Ab exhibits enhanced antitumor activity and has equal or slightly superior activity to their combination (Combi). It shows promise as a therapeutic agent, especially for use against tumors EGFR and/or VEGFR2 over-expressing malignancies.     

Preclinical antitumor activity of S‐222611, an oral reversible tyrosine kinase inhibitor of epidermal growth factor receptor and human epidermal growth factor receptor 2

Epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) are validated molecular targets in cancer therapy. Dual blockade has been explored and one such agent, lapatinib, is in clinical practice but with modest activity. Through chemical screening, we discovered a novel EGFR and HER2 inhibitor, S‐222611, that selectively inhibited both kinases with IC₅₀s below 10 nmol/L. S‐222611 also inhibited intracellular kinase activity and the growth of EGFR‐expressing and HER2‐expressing cancer cells. In addition, S‐222611 showed potent antitumor activity over lapatinib in a variety of xenograft models. In evaluations with two patient‐oriented models, the intrafemoral implantation model and the intracranial implantation model, S‐222611 exhibited excellent activity and could be effective against bone and brain metastasis. Compared to neratinib and afatinib, irreversible EGFR/HER2 inhibitors, S‐222611 showed equivalent or slightly weaker antitumor activity but a safer profile. These results indicated that S‐222611 is a potent EGFR and HER2 inhibitor with substantially better antitumor activity than lapatinib at clinically relevant doses. Considering the safer profile than for irreversible inhibitors, S‐222611 could be an important option in future cancer therapy.     

Gefitinib ('Iressa'), an epidermal growth factor receptor tyrosine kinase inhibitor, mediates the inhibition of lymph node metastasis in oral cancer cells

High expression of epidermal growth factor receptor (EGFR) is frequently observed in many solid tumor types including oral squamous cell carcinomas (OSCC). This study investigated whether treatment with gefitinib ('Iressa'), an EGFR-tyrosine kinase inhibitor, would inhibit the metastatic spread in OSCC cells. This was evaluated using orthotopic xenografts of highly metastatic OSCC. Metastasis was observed in six of 13 gefitinib treated animals (46.2%), compared with all of 12 control animals (100%). After exposure to gefitinib, OSCC cells showed a marked reduction in cell adhesion ability to fibronectin and in the expression of integrin alpha3, alphav, beta1, beta4, beta5 and beta6.     

Epidermal growth factor receptor (EGFR) downstream molecules as response predictive markers for gefitinib (Iressa, ZD1839) in chemotherapy-resistant non-small cell lung cancer

Gefitinib has shown meaningful antitumor activity with tolerable toxicity in chemotherapy-refractory NSCLC in previous studies. Moreover, EGFR expression failed to show a correlation with response. In an attempt to identify predictive markers of response, we have investigated the tumoral expression of key signaling molecules of EGFR (EGFR, p-EGFR, p-Akt, p-Erk, p-STAT3) by immunohistochemistry and analyzed their correlations with response. Of 65 patients who received gefitinib (250 mg/day) for chemotherapy-refractory NSCLC, there were 14 partial responses (21.5%), 21 stable diseases (32.3%) and 21 progressive diseases (32.3%). Median durations of overall survival and time to progression were 6.7 months and 2.8 months, respectively. Immunohistochemistry was performed in 34 patients with evaluable tissue specimens. EGFR was overexpressed (2+ or 3+) in 32.4% and p-EGFR was positive in 26.5%. The expressions of p-Akt, p-Erk and p-STAT3 were positive (1+ or 2+) in 50%, 38.2% and 79.4%, respectively. The EGFR expression was not correlated with p-EGFR or the downstream molecules. EGFR or p-EGFR status did not correlate with response. Positive expression of p-Erk was significantly associated with poor response (38.1% in -, 14.3% in 1+, 0% in 2+; p = 0.046). Furthermore, tumors with positive p-Akt and negative p-Erk nuclear expression exhibited the best response (60%), whereas there was no response in the opposite [p-Akt (-), p-Erk (+)] cases. Intense nuclear staining of p-Akt (2+) was associated with prolonged TTP (HR 0.25, 95% confidence interval [CI] 0.08-0.79, p = 0.018) and OS (HR 0.16, 95% CI 0.04-0.62, p = 0.008). These results support the assumption that gefitinib responsiveness might be predicted by activated EGFR downstream molecules such as p-Akt and p-Erk.     

Combination therapy with gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, gemcitabine and cisplatin in patients with advanced solid tumors.

BACKGROUND: The aim of this study was to investigate the tolerability, pharmacokinetic interaction and antitumor activity of gefitinib ("Iressa", ZD1839), an orally active, selective epidermal growth factor receptor tyrosine kinase inhibitor, combined with gemcitabine and cisplatin in chemotherapy-na?ve patients with advanced solid tumors. PATIENTS AND METHODS: This was an open-label feasibility trial evaluating two doses of gefitinib (250 and 500 mg/day) in combination with gemcitabine and cisplatin. Gefitinib was administered daily from day 2 onwards. Gemcitabine 1250 mg/m(2) was given on days 1 and 8 and cisplatin 80 mg/m(2) on day 1 for up to six 3-week cycles. Patients could then continue to receive gefitinib monotherapy. RESULTS: Eighteen patients were entered, nine at each gefitinib dose level. Two patients developed dose-limiting toxicity: one grade 3 convulsion (250 mg/day dose group) and one grade 3 rash (500 mg/day dose group). The most frequently occurring adverse events in the combination phase were vomiting (17 patients), asthenia (16), nausea (14), diarrhea (14) and skin rash (13). The most common grade 3/4 adverse events were vomiting (seven patients), asthenia (six), thrombocytopenia (six), diarrhea (five) and anorexia (five). Pharmacokinetic analyses showed no apparent pharmacokinetic interaction between gefitinib and cisplatin or gemcitabine, with the exception of a possible small increase in the geometric mean exposure to gemcitabine seen on day 8 of therapy when given alone with the higher dose of gefitinib. Of 17 evaluable patients, nine had confirmed partial responses, seven had stable disease and one had progressive disease. CONCLUSIONS: Combination therapy of gefitinib with cisplatin and gemcitabine had a manageable and predictable safety profile, no major effect on exposure to any of the three drugs and antitumor activity.     

Enhanced gefitinib‐induced repression of the epidermal growth factor receptor pathway by ataxia telangiectasia‐mutated kinase inhibition in non‐small‐cell lung cancer cells

The epidermal growth factor receptor (EGFR) tyrosine kinase signaling pathways regulate cellular activities. The EGFR tyrosine kinase inhibitors (EGFR‐TKIs) repress the EGFR pathway constitutively activated by somatic EGFR gene mutations and have drastically improved the prognosis of non‐small‐cell lung cancer (NSCLC) patients. However, some problems, including resistance, remain to be solved. Recently, combination therapy with EGFR‐TKIs and cytotoxic agents has been shown to improve the prognosis of NSCLC patients. To enhance the anticancer effects of EGFR‐TKIs, we examined the cross‐talk of the EGFR pathways with ataxia telangiectasia‐mutated (ATM) signaling pathways. ATM is a key protein kinase in the DNA damage response and is known to phosphorylate Akt, an EGFR downstream factor. We found that the combination of an ATM inhibitor, KU55933, and an EGFR‐TKI, gefitinib, resulted in synergistic cell growth inhibition and induction of apoptosis in NSCLC cell lines carrying the sensitive EGFR mutation. We also found that KU55933 enhanced the gefitinib‐dependent repression of the phosphorylation of EGFR and/or its downstream factors. ATM inhibition may facilitate the gefitinib‐dependent repression of the phosphorylation of EGFR and/or its downstream factors, to exert anticancer effects against NSCLC cells with the sensitive EGFR mutation.