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Gefitinib (Iressa)

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Latest Research Publications

Web Resources: Gefitinib (Iressa) (7 links)

Latest Research Publications

Chang H, Sung JH, Moon SU, et al.
EGF Induced RET Inhibitor Resistance in CCDC6-RET Lung Cancer Cells.
Yonsei Med J. 2017; 58(1):9-18 [PubMed] Free Access to Full Article Related Publications
PURPOSE: Rearrangement of the proto-oncogene rearranged during transfection (RET) has been newly identified potential driver mutation in lung adenocarcinoma. Clinically available tyrosine kinase inhibitors (TKIs) target RET kinase activity, which suggests that patients with RET fusion genes may be treatable with a kinase inhibitor. Nevertheless, the mechanisms of resistance to these agents remain largely unknown. Thus, the present study aimed to determine whether epidermal growth factor (EGF) and hepatocyte growth factor (HGF) trigger RET inhibitor resistance in LC-2/ad cells with CCDC6-RET fusion genes.
MATERIALS AND METHODS: The effects of EGF and HGF on the susceptibility of a CCDC6-RET lung cancer cell line to RET inhibitors (sunitinib, E7080, vandetanib, and sorafenib) were examined.
RESULTS: CCDC6-RET lung cancer cells were highly sensitive to RET inhibitors. EGF activated epidermal growth factor receptor (EGFR) and triggered resistance to sunitinib, E7080, vandetanib, and sorafenib by transducing bypass survival signaling through ERK and AKT. Reversible EGFR-TKI (gefitinib) resensitized cancer cells to RET inhibitors, even in the presence of EGF. Endothelial cells, which are known to produce EGF, decreased the sensitivity of CCDC6-RET lung cancer cells to RET inhibitors, an effect that was inhibited by EGFR small interfering RNA (siRNA), anti-EGFR antibody (cetuximab), and EGFR-TKI (Iressa). HGF had relatively little effect on the sensitivity to RET inhibitors.
CONCLUSION: EGF could trigger resistance to RET inhibition in CCDC6-RET lung cancer cells, and endothelial cells may confer resistance to RET inhibitors by EGF. E7080 and other RET inhibitors may provide therapeutic benefits in the treatment of RET-positive lung cancer patients.

He X, Zhang Y, Ma Y, et al.
Optimal tumor shrinkage predicts long-term outcome in advanced nonsmall cell lung cancer (NSCLC) treated with target therapy: Result from 3 clinical trials of advanced NSCLC by 1 institution.
Medicine (Baltimore). 2016; 95(31):e4176 [PubMed] Free Access to Full Article Related Publications
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are used as standard therapies for advanced nonsmall cell lung cancer (NSCLC) patients with EGFR mutation positive. Because these targeted therapies could cause tumor necrosis and shrinkage, the purpose of the study is to search for a value of optimal tumor shrinkage as an appropriate indicator of outcome for advanced NSCLC.A total of 88 NSCLC enrollees of 3 clinical trials (IRESSA registration clinical trial, TRUST study and ZD6474 study), who received Gefitinib (250 mg, QD), Erlotinib (150 mg, QD), and ZD6474 (100 mg, QD), respectively, during December 2003 and October 2007, were retrospectively analyzed. The response evaluation criteria in solid tumors (RECIST) were used to identify responders, who had complete response (CR) or partial responses (PR) and nonresponders who had stable disease (SD) or progressive disease (PD). Receiver operating characteristics (ROC) analysis was used to find the optimal tumor shrinkage as an indicator for tumor therapeutic outcome. Univariate and multivariate Cox regression analyses were performed to compare the progression-free survival (PFS) and overall survival (OS) between responders and nonresponders stratified based on radiologic criteria.Among the 88 NSCLC patients, 26 were responders and 62 were nonresponders based on RECIST 1.0. ROC indicated that 8.32% tumor diameter shrinkage in the sum of the longest tumor diameter (SLD) was the cutoff point of tumor shrinkage outcomes, resulting in 46 responders (≤8.32%) and 42 nonresponders (≥8.32%). Univariate and multivariate Cox regression analyses indicated that (1) the responders (≤8.32%) and nonresponders (≥ -8.32%) were significantly different in median PFS (13.40 vs 1.17 months, P < 0.001) and OS (19.80 vs 7.90 months, P < 0.001) and (2) -8.32% in SLD could be used as the optimal threshold for PFS (hazard ratio [HR], 8.11, 95% CI, 3.75 to 17.51, P < 0.001) and OS (HR, 2.36, 95% CI, 1.41 to 3.96, P = 0.001).However, 8.32% tumor diameter shrinkage is validated as a reliable outcome predictor of advanced NSCLC patients receiving EGFR-TKIs therapies and may provide a practical measure to guide therapeutic decisions.

Kazandjian D, Blumenthal GM, Yuan W, et al.
FDA Approval of Gefitinib for the Treatment of Patients with Metastatic EGFR Mutation-Positive Non-Small Cell Lung Cancer.
Clin Cancer Res. 2016; 22(6):1307-12 [PubMed] Related Publications
On July 13, 2015, the FDA approved gefitinib (Iressa; AstraZeneca UK Limited) for the treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors have EGFR exon 19 deletions or exon 21 (L858R) substitution mutations as detected by an FDA-approved test. Concurrently, a labeling expansion of the therascreen EGFR RGQ PCR Kit (Qiagen) as a companion diagnostic test was approved. The approval was based on the results of a multicenter, single-arm, open-label clinical study of 106 treatment-naïve patients with metastatic EGFR mutation-positive NSCLC who received gefitinib, 250 mg daily, until disease progression or intolerable toxicity. The major efficacy outcome was RECIST v1.1 objective response rate (ORR). The blinded independent central review (BICR) ORR was 50% [95% confidence interval (CI), 41-59] with a median duration of response (DoR) of 6.0 months. Efficacy results were supported by a retrospective exploratory analysis of a subset of a randomized, multicenter, open-label trial on 1,217 patients with metastatic NSCLC. Of the patients randomized, 186 (15%) were retrospectively determined to be EGFR positive and evaluable for a BICR assessment. The HR for progression-free survival (PFS) was 0.54 (95% CI, 0.38-0.79), favoring gefitinib over platinum-doublet chemotherapy. The most common (≥20%) adverse reactions were skin reactions, increased aspartate and alanine aminotransferase, proteinuria, and diarrhea. Approximately 5% of patients discontinued treatment due to an adverse reaction. Given the safety profile and clinically meaningful ORR, DoR, and PFS, the benefit-risk analysis was deemed favorable for FDA approval.

Gautschi O, Stadelmann C, Aebersold-Keller F, et al.
Mutation Profiling of Lung Cancers with Long-Term Response to Gefitinib Therapy.
Oncol Res Treat. 2015; 38(11):560-9 [PubMed] Related Publications
BACKGROUND: The role of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) in the treatment of patients with advanced non-small cell lung cancer (NSCLC) and unknown EGFR mutation status has recently been questioned.
PATIENTS AND METHODS: We conducted a retrospective study of patients with unknown EGFR mutation status and long-term response (LTR) to gefitinib in the Swiss Iressa expanded access program (EAP). We assessed patient characteristics, and performed Sanger sequencing and next generation sequencing on archived tumor tissue. We hypothesized that EGFR mutations are prevalent in patients with LTR.
RESULTS: Of 430 patients in the EAP, 18 (4%) fulfilled our definition of LTR, and 16 of them had archived tumor tissue. Patient characteristics were as expected for age, sex, and smoking history. Median duration of therapy was 38 months (range 24-142 months). Sanger sequencing revealed EGFR exon 18-21 mutations in 6 (38%) of the tumors. Next generation sequencing revealed no further EGFR-mutated cases, but reported in 15 (94%) of the tumors mutations in other genes (ALK, BRAF, DDR2, KEAP1, MET, PTEN, STK11) previously associated with NSCLC.
CONCLUSION: Larger studies are needed to define the prognostic values of different driver mutations in patients with NSCLC.

Bi Y, Deng J, Murry DJ, An G
A Whole-Body Physiologically Based Pharmacokinetic Model of Gefitinib in Mice and Scale-Up to Humans.
AAPS J. 2016; 18(1):228-38 [PubMed] Free Access to Full Article Related Publications
Gefitinib (Iressa) is a selective and potent EGFR tyrosine kinase inhibitor. It received an accelerated FDA approval in 2003 for the treatment of patients with nonsmall cell lung cancer (NSCLC) and represents the first-line therapy for NSCLC with EGFR mutations. In the work presented herein, the disposition of gefitinib was investigated extensively in mouse in both plasma and 11 organs (liver, heart, lung, spleen, gut, brain, skin, fat, eye, kidney, and muscle) after a single IV dose of 20 mg/kg. Gefitinib demonstrated extensive distribution in most tissues, except for the brain, and tissue to plasma partition coefficients (K pt) ranged from 0.71 (brain) to 40.5 (liver). A comprehensive whole-body physiologically based pharmacokinetic (PBPK) model of gefitinib in mice was developed, which adequately captured gefitinib concentration-time profiles in plasma and various tissues. Predicted plasma and tissue AUC values agreed well with the values calculated using the noncompartmental analysis (<25% difference). The PBPK model was further extrapolated to humans after taking into account the interspecies differences in physiological parameters. The simulated concentrations in human plasma were in line with the observed concentrations in healthy volunteers and patients with solid malignant tumors after both IV infusion and oral administration. Considering the extensive tissue distribution of gefitinib, plasma concentration may not be an ideal surrogate marker for gefitinib exposure at the target site or organ of toxicity (such as the skin). Since our whole-body PBPK model can predict gefitinib concentrations not only in plasma but also in various organs, our model may have clinical applications in efficacy and safety assessment of gefitinib.

Li Q, Zhang D, Chen X, et al.
Nuclear PKM2 contributes to gefitinib resistance via upregulation of STAT3 activation in colorectal cancer.
Sci Rep. 2015; 5:16082 [PubMed] Free Access to Full Article Related Publications
Gefitinib (Iressa, ZD-1839), a small molecule tyrosine kinase inhibitor (TKI) of the epidermal growth factor receptor (EGFR) pathway, is currently under investigation in clinical trials for the treatment of colorectal cancer (CRC). However, as known, some patients develop resistance to TKIs, and the mechanisms mediating intrinsic resistance to EGFR-TKIs in CRC have not been fully characterized. Resistance to EGFR inhibitors reportedly involves activation of signal transducer and activator of transcription 3 (STAT3) in glioma and lung cancer. Here, we demonstrated that the nuclear pyruvate kinase isoform M2 (PKM2) levels were positively correlated with gefitinib resistance in CRC cells. The overexpression of nuclear PKM2 in HT29 cells decreased the effect of gefitinib therapy, whereas PKM2 knockdown increased gefitinib efficacy. Furthermore, the activation of STAT3 by nuclear PKM2 was associated with gefitinib resistance. Inhibition of STAT3 by Stattic, a STAT3-specific inhibitor, or STAT3-specific siRNA sensitized resistant cells to gefitinib. These results suggest that nuclear PKM2 modulates the sensitivity of CRC cells to gefitinib and indicate that small molecule pharmacological disruption of nuclear PKM2 association with STAT3 is a potential avenue for overcoming EGFR-TKI resistance in CRC patients.

Tetsu O, Phuchareon J, Eisele DW, et al.
AKT inactivation causes persistent drug tolerance to EGFR inhibitors.
Pharmacol Res. 2015; 102:132-7 [PubMed] Related Publications
Drug resistance is a major obstacle to the success of EGFR-targeted therapy. We recently studied the mechanism by which a small subset of EGFR mutant lung cancer cells remains viable after EGFR inhibition. We found that this drug-tolerant subpopulation develops because EGFR inhibition prevents AKT activity and thus inactivates Ets-1 function. In this article, we discuss how changes in intrinsic cell signaling after EGFR inhibition open a new avenue to drug resistance in NSCLCs, and comment on combined TKI and MEK inhibitor treatment to reduce the probability of emergent resistance to EGFR TKIs.

Narita Y, Matsushima Y, Shiroiwa T, et al.
Cost-effectiveness analysis of EGFR mutation testing and gefitinib as first-line therapy for non-small cell lung cancer.
Lung Cancer. 2015; 90(1):71-7 [PubMed] Related Publications
OBJECTIVES: The combination use of gefitinib and epidermal growth factor receptor (EGFR) testing is a standard first-line therapy for patients with non-small cell lung cancer (NSCLC). Here, we examined the cost-effectiveness of this approach in Japan.
MATERIALS AND METHODS: Our analysis compared the 'EGFR testing strategy', in which EGFR mutation testing was performed before treatment and patients with EGFR mutations received gefitinib while those without mutations received standard chemotherapy, to the 'no-testing strategy,' in which genetic testing was not conducted and all patients were treated with standard chemotherapy. A three-state Markov model was constructed to predict expected costs and outcomes for each strategy. We included only direct medical costs from the healthcare payer's perspective. Outcomes in the model were based on those reported in the Iressa Pan-Asia Study (IPASS). The incremental cost-effectiveness ratio (ICER) was calculated using quality-adjusted life-years (QALYs) gained. Sensitivity and scenario analyses were conducted.
RESULTS: The incremental cost and effectiveness per patient of the 'EGFR testing strategy' compared to the 'no-testing strategy' was estimated to be approximately JP¥122,000 (US$1180; US$1=JP¥104 as of February 2014) and 0.036 QALYs. The ICER was then calculated to be around JP¥3.38 million (US$32,500) per QALY gained. These results suggest that the 'EGFR testing strategy' is cost-effective compared with the 'no-testing strategy' when JP¥5.0 million to 6.0 million per QALY gained is considered an acceptable threshold. These results were supported by the sensitivity and scenario analyses.
CONCLUSION: The combination use of gefitinib and EGFR testing can be considered a cost-effective first-line therapy compared to chemotherapy such as carboplatin-paclitaxel for the treatment for NSCLC in Japan.

Greenhalgh J, Bagust A, Boland A, et al.
Erlotinib and gefitinib for treating non-small cell lung cancer that has progressed following prior chemotherapy (review of NICE technology appraisals 162 and 175): a systematic review and economic evaluation.
Health Technol Assess. 2015; 19(47):1-134 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Lung cancer is the second most diagnosed cancer in the UK. Over 70% of lung cancers are non-small cell lung cancers (NSCLCs). Patients with stage III or IV NSCLC may be offered treatment to improve survival, disease control and quality of life. One-third of these patients receive further treatment following disease progression; these treatments are the focus of this systematic review.
OBJECTIVES: To appraise the clinical effectiveness and cost-effectiveness of erlotinib [Tarceva(®), Roche (UK) Ltd] and gefitinib (IRESSA(®), AstraZeneca) compared with each other, docetaxel or best supportive care (BSC) for the treatment of NSCLC after disease progression following prior chemotherapy. The effectiveness of treatment with gefitinib was considered only for patients with epidermal growth factor mutation-positive (EGFR M+) disease.
DATA SOURCES: Four electronic databases (EMBASE, MEDLINE, The Cochrane Library, PubMed) were searched for randomised controlled trials (RCTs) and economic evaluations. Manufacturers' evidence submissions to the National Institute for Health and Care Excellence were also considered.
REVIEW METHODS: Outcomes for three distinct patient groups based on EGFR mutation status [EGFR M+, epidermal growth factor mutation negative (EGFR M-) and epidermal growth factor mutation status unknown (EGFR unknown)] were considered. Heterogeneity of the data precluded statistical analysis. A de novo economic model was developed to compare treatments (incremental cost per quality-adjusted life-year gained).
RESULTS: Twelve trials were included in the review. The use of gefitinib was compared with chemotherapy (n = 6) or BSC (n = 1), and the use of erlotinib was compared with chemotherapy (n = 3) or BSC (n = 1). One trial compared the use of gefitinib with the use of erlotinib. No trials included solely EGFR M+ patients; all data were derived from retrospective subgroup analyses from six RCTs [Kim ST, Uhm JE, Lee J, Sun JM, Sohn I, Kim SW, et al. Randomized phase II study of gefitinib versus erlotinib in patients with advanced non-small cell lung cancer who failed previous chemotherapy. Lung Cancer 2012;75:82-8, V-15-32, Tarceva In Treatment of Advanced NSCLC (TITAN), BR.21, IRESSA Survival Evaluation in Lung cancer (ISEL) and IRESSA NSCLC Trial Evaluating REsponse and Survival versus Taxotere (INTEREST)]. These limited data precluded conclusions regarding the clinical effectiveness of any treatment for EGFR M+ patients. For EGFR M- patients, data were derived from the TArceva Italian Lung Optimization tRial (TAILOR) trial and Docetaxel and Erlotinib Lung Cancer Trial (DELTA). Retrospective data were also derived from subgroup analyses of BR.21, Kim et al., TITAN, INTEREST and ISEL. The only statistically significant reported results were for progression-free survival (PFS) for TAILOR and DELTA, and favoured docetaxel over erlotinib [TAILOR hazard ratio (HR) 1.39, 95% confidence interval (CI) 1.06 to 1.82; DELTA HR 1.44, 95% CI 1.08 to 1.92]. In EGFR unknown patients, nine trials (INTEREST, IRESSA as Second-line Therapy in Advanced NSCLC - KoreA, Li, Second-line Indication of Gefitinib in NSCLC, V-15-32, ISEL, DELTA, TITAN and BR.21) reported overall survival data and only one (BR.21) reported a statistically significant result favouring the use of erlotinib over BSC (HR 0.7, 95% CI 0.58 to 0.85). For PFS, BR.21 favoured the use of erlotinib when compared with BSC (HR 0.61, 95% CI 0.51 to 0.74) and the use of gefitinib was favoured when compared with BSC (HR 0.82, 95% CI 0.73 to 0.92) in ISEL. Limitations in the clinical data precluded assessment of cost-effectiveness of treatments for an EGFR M+ population by the Assessment Group (AG). The AG's economic model suggested that for the EGFR M- population, the use of erlotinib was not cost-effective compared with the use of docetaxel and compared with BSC. For EGFR unknown patients, the use of erlotinib was not cost-effective when compared with BSC.
CONCLUSIONS/FUTURE WORK: The lack of clinical data available for distinct patient populations limited the conclusions of the assessment. Future trials should distinguish between patients with EGFR M+ and EGFR M- disease.
FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Seo YH
Discovery of 2',4'-dimethoxychalcone as a Hsp90 inhibitor and its effect on iressa-resistant non-small cell lung cancer (NSCLC).
Arch Pharm Res. 2015; 38(10):1783-8 [PubMed] Related Publications
Heat shock protein 90 (Hsp90) is a ATP dependent molecular chaperone and has emerged as an attractive therapeutic target in the war on cancer due to its role in regulating maturation and stabilization of numerous oncogenic proteins. In this study, we discovered that 2',4'-dimethoxychalcone (1b) disrupted Hsp90 chaperoning function and inhibited the growth of iressa-resistant non-small cell lung cancer (NSCLC, H1975). The result suggested that 2',4'-dimethoxychalcone (1b) could serve as a potential therapeutic lead to circumvent the drug resistance acquired by EGFR mutation and Met amplification.

Hsu CP, Lee LW, Tang SC, et al.
Epidermal growth factor activates telomerase activity by direct binding of Ets-2 to hTERT promoter in lung cancer cells.
Tumour Biol. 2015; 36(7):5389-98 [PubMed] Related Publications
Growth signals are directly or indirectly involved in telomerase regulation. In this study, we investigated molecular mechanisms of the effect of EGF (epidermal growth factor) on regulating hTERT (human telomerase reverse transcriptase) expression. To elucidate specific transcription factors involved in EGF-stimulated hTERT transcription in A549 and H1299 lung cancer cells, transcription factors drives hTERT promoter activity, such as Myc, Mad, and Ets-2, was evaluated on luciferase reporter assay. The upregulation of hTERT promoter by Ets-2 and Myc were abolished by Mad. Using DAPA (DNA affinity precipitation assay), Ets-2 binding to SNP (T) was stronger than Ets-2 binding to SNP (C) at -245 bp upstream of the transcription start site within the core promoter of hTERT. Ets-2 silence by siRNA decreased hTERT expression at mRNA and protein levels. The regulation of hTERT promoter by EGF/Ets-2 was diminished via the EGFR kinase signal pathway-specific inhibitors AG1478 and Iressa. Inhibitors of Erk and Akt inhibited Ets-2-activated hTERT promoter activity. These data suggested that Ets-2, a genuine cancer-specific transcription factor, is actively involved in EGFR kinase-induced hTERT overexpression pathway in lung cancer cells. Blockage of this pathway may contribute to targeted gene therapy in lung cancer.

Tung CL, Jian YJ, Syu JJ, et al.
Down-regulation of ERK1/2 and AKT-mediated X-ray repair cross-complement group 1 protein (XRCC1) expression by Hsp90 inhibition enhances the gefitinib-induced cytotoxicity in human lung cancer cells.
Exp Cell Res. 2015; 334(1):126-35 [PubMed] Related Publications
Gefitinib (Iressa(R), ZD1839) is a selective epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) that blocks growth factor-mediated cell proliferation and extracellular signal-regulated kinases 1/2 (ERK1/2) and AKT signaling activation. It has been shown that inhibition of Hsp90 function can enhance antitumor activity of EGFR-TKI. XRCC1 is an important scaffold protein in base excision repair, which could be regulated by ERK1/2 and AKT pathways. However, the role of ERK1/2 and AKT-mediated XRCC1 expression in gefitinib alone or combination with an Hsp90 inhibitor-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. In this study, gefitinib treatment decreased XRCC1 mRNA and protein expression through ERK1/2 and AKT inactivation in two NSCLC cells, A549 and H1975. Knocking down XRCC1 expression by transfection with small interfering RNA of XRCC1 enhanced the cytotoxicity and cell growth inhibition of gefitinib. Combining treatment of gefitinib with an Hsp90 inhibitor resulted in enhancing the reduction of XRCC1 protein and mRNA levels in gefitinib-exposed A549 and H1975 cells. Compared to a single agent alone, gefitinib combined with an Hsp90 inhibitor resulted in cytotoxicity and cell growth inhibition synergistically in NSCLC cells. Furthermore, transfection with constitutive active MKK1 or AKT vectors rescued the XRCC1 protein level as well as the cell survival suppressed by an Hsp90 inhibitor and gefitinib. These findings suggested that down-regulation of XRCC1 can enhance the sensitivity of gefitinib for NSCLC cells.

Dhillon S
Gefitinib: a review of its use in adults with advanced non-small cell lung cancer.
Target Oncol. 2015; 10(1):153-70 [PubMed] Related Publications
Gefitinib (Iressa®) is a selective small-molecule epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (EGFR TKI) indicated for the treatment of adults with locally advanced or metastatic non-small cell lung cancer (NSCLC) with activating mutations of EGFR tyrosine kinase. Large phase III or IV clinical trials in patients with locally advanced or metastatic NSCLC showed that gefitinib as first- or subsequent-line treatment significantly prolonged progression-free survival (PFS) and improved objective response rates and/or health-related quality of life parameters in patients with activating EGFR mutations and in clinically selected patients (e.g., Asian patients or never-smokers) who are more likely to harbour these mutations. Overall survival did not increase significantly with gefitinib, although post-study treatments may have had a confounding effect on this outcome. Gefitinib was generally well tolerated in these studies, with mild or moderate skin reactions, gastrointestinal disturbances and elevations in liver enzymes among the most common adverse reactions in gefitinib recipients; interstitial lung disease has also been reported in <6 % of gefitinib recipients. Compared with chemotherapy, gefitinib as first- or subsequent-line therapy provided similar or greater PFS benefit and was generally associated with fewer haematological adverse events, neurotoxicity, asthenic disorders, as well as grade ≥3 adverse events. Although the position of gefitinib with respect to other EGFR TKIs is not definitively established, current evidence indicates that gefitinib monotherapy is an effective and generally well-tolerated first- or subsequent-line treatment option for patients with NSCLC and activating EGFR mutations who have not received an EGFR TKI previously.

Kim Y, Apetri M, Luo B, et al.
Differential Effects of Tyrosine Kinase Inhibitors on Normal and Oncogenic EGFR Signaling and Downstream Effectors.
Mol Cancer Res. 2015; 13(4):765-74 [PubMed] Free Access to Full Article Related Publications
UNLABELLED: Constitutive activation of EGFR due to overexpression or mutation in tumor cells leads to dysregulated downstream cellular signaling pathways. Therefore, EGFR as well as its downstream effectors have been identified as important therapeutic targets. The FDA-approved small-molecule inhibitors of EGFR, gefitinib (Iressa) and erlotinib (Tarceva), are clinically effective in a subset of patients with non-small cell lung cancer (NSCLC) whose tumors harbor activating mutations within the kinase domain of EGFR. The current study examined effects of these drugs in 32D cells expressing native (WT) or oncogenic (L858R) EGFR as well as in cancer cell lines A431 and H3255. Distinct patterns for gefitinib and erlotinib inhibition of EGFR autophosphorylation at individual tyrosines were revealed for wild-type (WT) and L858R EGFR. Phosphorylation of Y845 has been shown to be important in cancer cells and Y1045 phosphorylation is linked to Cbl-mediated ubiquitination and degradation. Dramatic differences were observed by greater potency of these drugs for inhibiting downstream effectors for L858R EGFR including Cbl and STAT5. Selective targeting of Cbl may play a role in oncogene addiction and effects on STAT5 identify features of signaling circuitry for L858R EGFR that contribute to drug sensitivity and clinical efficacy. These data provide new understanding of the EGFR signaling environment and suggest useful paradigms for predicting patient response to EGFR-targeted therapy as well as combination treatments.
IMPLICATIONS: This study offers fundamental insights for understanding molecular mechanisms of drug sensitivity on oncogenic forms of EGFR and downstream signaling components as well as considerations for further drug optimization and design of combination therapy.

Han JY, Lee SH, Lee GK, et al.
Phase I/II study of gefitinib (Iressa(®)) and vorinostat (IVORI) in previously treated patients with advanced non-small cell lung cancer.
Cancer Chemother Pharmacol. 2015; 75(3):475-83 [PubMed] Free Access to Full Article Related Publications
PURPOSE: Vorinostat has been shown to overcome resistance to gefitinib. We performed a phase I/II study combining gefitinib with vorinostat in previously treated non-small cell lung cancer (NSCLC).
METHODS: A 3 + 3 dose-escalation design was used to determine maximum tolerated dose (MTD) and recommended phase II dose (RP2D). Three dose levels were tested: 250 mg/day gefitinib on days 1-28 and 200, 300 or 400 mg/day vorinostat on days 1-7, and 15-21 out of every 28 days. The primary endpoint was median progression-free survival (PFS).
RESULTS: Fifty-two patients were enrolled and treated (43 in phase II). The median age was 59 years, 28 patients were male, 44 had adenocarcinoma, 29 had never smoked, and 36 had undergone one prior treatment. Twenty-two patients exhibited sensitive EGFR mutations. Planned dose escalation was completed without reaching the MTD. The RP2D was 250 mg gefitinib and 400 mg vorinostat. In 43 assessable patients in phase II, the median PFS was 3.2 months; the overall survival (OS) was 19.0 months. There were 16 partial responses and six cases of stable disease. In EGFR-mutant NSCLC, response rate was 77 %, median PFS was 9.1 months, and median OS was 24.1 months. The most common adverse events were anorexia and diarrhea.
CONCLUSIONS: Treatment with 250 mg gefitinib daily with biweekly 400 mg/day vorinostat was feasible and well tolerated. In an unselected patient population, this combination dose did not improve PFS. However, this combination showed a potential for improving efficacy of gefitinib in EGFR-mutant NSCLC (NCT01027676).

Zhao H, Fan Y, Ma S, et al.
Final overall survival results from a phase III, randomized, placebo-controlled, parallel-group study of gefitinib versus placebo as maintenance therapy in patients with locally advanced or metastatic non-small-cell lung cancer (INFORM; C-TONG 0804).
J Thorac Oncol. 2015; 10(4):655-64 [PubMed] Related Publications
BACKGROUND: The results of the Iressa in NSCLC for maintenance study (NCT00770588; C-TONG 0804), which compared gefitinib and placebo as maintenance therapy in patients with advanced non-small-cell lung cancer without disease progression after first-line chemotherapy, were published previously. The objective of this report is to provide a mature analysis of overall survival (OS) for Iressa in NSCLC for maintenance study in intention to treat (ITT) population and in subgroups according to epidermal growth factor receptor (EGFR) mutation status.
PATIENTS AND METHODS: A total of 296 patients were randomly assigned. EGFR mutations were detected using an amplification mutation refractory system. Seventy-nine patients were assessable for EGFR mutations. OS was analyzed by a Cox proportional hazards model adjusted for the same covariates in ITT population and subgroups according to EGFR mutation status.
RESULTS: OS was similar for gefitinib and placebo arm with no significant difference between treatments in ITT population (hazard ratio [HR], 0.88; 95% confidence interval [CI], 0.68-1.14; p = 0.335) and in subgroups with wild type EGFR (HR, 1.27; 95% CI, 0.7-2.3; p = 0.431) or unknown EGFR mutations (HR, 0.92; 95% CI, 0.68, 1.25; p = 0.603). In the EGFR mutation-positive subgroup, the gefitinib arm showed a higher OS than the placebo arm (HR, 0.39; 95% CI, 0.15, 0.97; p = 0.036).
CONCLUSION: EGFR mutation was the strongest predictive biomarker for OS benefit of gefitinib as maintenance treatment. The analyses of OS showed that patients achieve a clear and significant survival benefit if they receive EGFR tyrosine kinase inhibitors as maintenance treatment in EGFR mutation-positive patients.

Li J, Lin B, Li X, et al.
Biomarkers for predicting response to tyrosine kinase inhibitors in drug-sensitive and drug-resistant human bladder cancer cells.
Oncol Rep. 2015; 33(2):951-7 [PubMed] Related Publications
The epidermal growth factor receptor (EGFR) family is reportedly overexpressed in bladder cancer, and tyrosine kinase inhibitors (TKIs) have been suggested as treatment. Gefitinib (Iressa®) is a selective inhibitor of the EGFR and lapatinib is a dual inhibitor of both the EGFR and HER2 (human EGFR type 2 receptor). Both compounds compete with the binding of ATP to the tyrosine kinase domain of the respective receptors to inhibit receptor autophosphorylation causing suppression of signal transduction. Unfortunately, resistance to these inhibitors is a major clinical issue. The purpose of the present study was to use protein array analysis to compare the signaling pathway(s) induced by gefitinib and lapatinib, in UM-UC-5 (drug-sensitive) and UM-UC-14 (drug-resistant) bladder cancer cells and to identify molecular markers that may be useful predictors of their efficacy. The results revealed that phosphorylation of EGFR, HER3, Met and ERK1/2 was markedly overexpressed in the sensitive cell line (UM-UC-5) and was strongly inhibited by the TKIs. Other notable differences included decreased phosphorylation of RSK, GSK3, AMPK, Akt and c-Jun by TKIs in the sensitive cells. In contrast, phosphorylated p53 was highly expressed in the resistant cell line (UM-UC-14) and TKIs had no effect in the resistant cells. Overall results suggest that phosphorylated HER3, ERK1/2 and p53 may be used as biomarkers to determine the sensitivity of bladder cancers to TKIs. In particular, a combination of these markers may be more likely to predict the sensitivity to TKIs.

Katahira K, Yoshikawa T, Enoki H, et al.
Is the evidence of the Supreme Court Ruling of gefitinib litigation in Japan scientific?
Int J Risk Saf Med. 2014; 26(4):227-33 [PubMed] Related Publications
BACKGROUND: Plaintiffs of the gefitinib (Iressa) lawsuits in Japan started in 2004 were defeated in the Supreme Court in 2013. The Court judged it was not possible to foresee the outbreak of deaths caused by interstitial pneumonia due to gefitinib from death cases before approval of this drug.
OBJECTIVE: We attempted to verify validity of this judgment.
METHODS: We estimated the 95% confidence interval (CI) of the proportion of onset and death cases among 23 onset and 13 death cases occurring from "within 1 week" to "within 4 weeks" from clinical data before approval of this drug using data admitted to the Court.
RESULTS: For death cases, all of the upper limits of the 95% CI exceeded 50% within 1-4 weeks. This fact suggested that the cases of acute interstitial pneumonia were included in the clinical trial before the approval of gefitinib.
CONCLUSION: It was possible to foresee the outbreak of death cases after drug approval. This conclusion showed the Court's ruling was not reasonable and was unscientific.

Wang J, Qin X, Zhang Z, et al.
Crotoxin suppresses the tumorigenic properties and enhances the antitumor activity of Iressa® (gefinitib) in human lung adenocarcinoma SPCA‑1 cells.
Mol Med Rep. 2014; 10(6):3009-14 [PubMed] Related Publications
Crotoxin (CrTX) is a neurotoxin isolated from the venom of the South American rattlesnake. Previous studies demonstrated that CrTX was able to inhibit the activity of the growth factor receptor tyrosine kinase and that CrTX possesses potent antitumor activity when combined with Iressa, an epidermal growth factor receptor inhibitor. The aim of the present study was to determine the antitumor effect of CrTX and the combination of CrTX with Iressa in lung adenocarcinoma SPCA‑1 cells. The results demonstrated that CrTX inhibited the cellular growth of SPCA‑1 cells via G1 arrest and induction of apoptosis. In addition, the c‑Jun N‑terminal kinase pathway was important in CrTX‑induced apoptosis in SPCA‑1 cells. Notably, CrTX was able to significantly enhance the cytotoxic effects of Iressa in SPCA‑1 cells. The in vivo antitumor assay demonstrated that treatment with either CrTX or Iressa significantly inhibited tumor growth, while the combination of CrTX and Iressa demonstrated the most significant antitumor activity, which was reflected by tumor weight and angiogenesis, presented as microvascular density. Therefore, the present study suggested that CrTX is a potential anti‑lung cancer agent and sensitizer of Iressa.

Kuiper JL, Heideman DA, Würdinger T, et al.
Rationale and study design of the IRENE-trial (NVALT-16): a phase II trial to evaluate iressa rechallenge in advanced NSCLC patients with an activating EGFR mutation who responded to an EGFR-TKI used as first-line or previous treatment.
Clin Lung Cancer. 2015; 16(1):60-6 [PubMed] Related Publications
BACKGROUND: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have shown improved progression-free survival (PFS) and overall survival (OS) over chemotherapy in a molecularly defined subgroup of advanced non-small-cell lung cancer (NSCLC) patients (ie, patients with an activating mutation in the EGFR gene). Nevertheless, all EGFR-mutated NSCLC patients develop TKI resistance eventually and there is no registered treatment or therapeutic strategy available for these patients. Several retrospective or small cohort studies have described patients who re-responded to EGFR-TKI treatment after a TKI-free interval ('drug holiday'). To date, no large prospective evaluation of the clinical effects of EGFR-TKI rechallenge in EGFR-mutated NSCLC patients has been performed.
PATIENTS AND METHODS: The IRENE (Iressa RE-challenge in advanced, EGFR-mutated NSCLC patients who responded to an EGFR-TKI used as first-line or previous treatment) (Dutch association for pulmonologists [NVALT]-16) trial is a multicenter, open-label, single-arm, single-stage, phase II study to evaluate gefitinib rechallenge in EGFR-mutated NSCLC patients who were previously treated with a TKI followed by a subsequent line of treatment (excluding EGFR-TKIs). The primary objective is disease control rate according to Response Evaluation Criteria in Solid Tumors criteria. Secondary objectives are objective response rate, PFS, OS, mutation characterization of sequential biopsies, VeriStrat correlation to PFS and OS, analysis of tumor-derived RNA in blood platelets and analysis of cell-free DNA in blood plasma.
RESULTS: The IRENE (NVALT-16) trial will evaluate the safety, efficacy, and feasibility of readministration of gefitinib after an EGFR-TKI-free interval in EGFR-mutated NSCLC patients.
CONCLUSION: The study will evaluate gefitinib re-challenge in EGFR-mutated NSCLC patients. The study will also provide more insight into the dynamic development of molecular characteristics of EGFR-mutated NSCLC along the course of the disease.

Mints M, Souchelnytskyi S
Impact of combinations of EGF, TGFβ, 17β-oestradiol, and inhibitors of corresponding pathways on proliferation of breast cancer cell lines.
Exp Oncol. 2014; 36(2):67-71 [PubMed] Related Publications
AIM: The impact of combinations of anti-cancer drugs and growth factors on tumour cells may differ from the assumed sum of the effects of each factor separately. Therefore it is important to study the effects of different combinations of various drugs and treatments. Our aim was to study the effects on breast cancer cell proliferation of EGF, TGFβ and 17β-oestradiol, three important regulators of breast tumourigenesis, and their respective inhibitors in different combinations.
MATERIALS AND METHODS: We screened the effects on proliferation of MCF7 and MDA-MB-231 cells of ninety different combinations of EGF, TGFβ and 17β-oestradiol, Iressa, SB431542 and Tamoxifen. Meta-data analysis of available clinical data was performed to validate observed proliferation data.
RESULTS: In MDA-MB-231 cells, TGFβ1 was found inhibitory when cells were simultaneously treated with EGF and 17β-oestradiol, with the effect potentiated by addition of all inhibitors combined. In the same cells, Iressa when combined with EGF was paradoxically stimulatory. Tamoxifen inhibited MCF7 cells co-treated with EGF or oestrogen, and enhanced the inhibitory effect of TGFβ in MDA-MB-231 cells. Meta-analysis of clinical gene expression studies confirmed several of these points, showing enhanced TGFβ and EGF expression in Tamoxifen-treated patients to correlate with decreased tumour size and grade respectively, and combined TGFβ-EGF expression to decrease the risk of metastasis.
CONCLUSION: Our study shows significant differences in proliferation response to drugs and growth factors between MCF7 cells which do not have propensity to form metastases in animal models and MDA-MB-231 cells which may form metastases upon inoculation into animals. Several of these differences are unexpected and confirmed by clinical observations.

Yang JC, Kang JH, Mok T, et al.
First-line pemetrexed plus cisplatin followed by gefitinib maintenance therapy versus gefitinib monotherapy in East Asian patients with locally advanced or metastatic non-squamous non-small cell lung cancer: a randomised, phase 3 trial.
Eur J Cancer. 2014; 50(13):2219-30 [PubMed] Related Publications
BACKGROUND: In the Iressa Pan-ASia Study (IPASS), gefitinib claimed improved progression-free survival (PFS) versus carboplatin-paclitaxel in clinically selected lung cancer patients. The primary objective of this study was to assess the PFS of pemetrexed-cisplatin (PC) followed by gefitinib maintenance versus gefitinib monotherapy in an IPASS-like population.
METHODS: In this open-label, randomised, phase 3 trial, eligible patients were ⩾18 years, chemonaïve, East Asian, light ex-smokers/never-smokers with advanced non-squamous non-small cell lung cancer, an Eastern Cooperative Oncology Group (ECOG) performance status 0-1 and unknown epidermal growth factor receptor (EGFR) mutation status who enrolled at 12 sites in Asia. Patients randomly received (1:1) pemetrexed (500 mg/m(2)) plus cisplatin (75mg/m(2)) for six 21-day cycles, followed by gefitinib maintenance or gefitinib monotherapy (250 mg/day). Patient tissue was retrospectively analysed for EGFR mutations. This study is registered with ClinicalTrials.gov, NCT01017874.
FINDINGS: Between 23rd November 2009 and 27th April 2012, 253 patients entered, and 236 patients were randomly assigned to and treated with PC therapy (N=114) and gefitinib monotherapy (N=118). Between-arm baseline characteristics were balanced. PFS was not significantly different between treatment arms (p=0.217). The unadjusted hazard ratio (HR) was 0.85 (95% confidence interval (CI) 0.63-1.13). The HR should be cautiously interpreted as it was not constant. EGFR mutation status was determined for 74 tissue samples; 50 (67.6%) had mutations. In a pre-specified subgroup analysis, only the treatment-by-EGFR mutation interaction was significant (p=0.008) for PFS. For the entire treatment period, a higher proportion of patients in the PC/gefitinib arm versus gefitinib experienced possibly drug-related grade 3-4 treatment-emergent adverse events (39 of 114 [34%] versus 19 of 118 [16%]; p=0.002).
INTERPRETATION: In the intention-to-treat (ITT) population, PFS was not significantly different. In the biomarker-assessable population, front-line EGFR tyrosine kinase inhibitor monotherapy was not efficacious in patients with wild-type EGFR. Identification of EGFR mutation status is key in the management of advanced non-squamous non-small cell lung cancer.
FUNDING: Eli Lilly and Company.

Han SY, Ding HR, Zhao W, et al.
Enhancement of gefitinib-induced growth inhibition by Marsdenia tenacissima extract in non-small cell lung cancer cells expressing wild or mutant EGFR.
BMC Complement Altern Med. 2014; 14:165 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: 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.
METHODS: Dose response curves for gefitinib and MTE were generated for two sensitive NSCLC cell lines with mutant or wild type EGFR status. Three different sequential combinations of MTE and gefitinib on cell growth were evaluated using IC50 and Combination Index approaches. The flow cytometric method was used to detect cell apoptosis and cell cycle profile. The impact of MTE combined with gefitinib on cell molecular network response was studied by Western blotting.
RESULTS: Unlike in the resistant NSCLC cells, our results revealed that low cytotoxic dose of MTE (8 mg/ml) combined gefitinib with three different schedules synergistically or additively enhanced the growth inhibition of gefitinib. Among which, MTE→MTE+gefitinib treatment was the most effective one. MTE markedly prompted cell cycle arrest and apoptosis caused by gefitinib both in EGFR mutant (HCC827) and wild type of NSCLC cells (H292). The Western blotting results showed that MTE→MTE+gefitinib treatment further enhanced the suppression of gefitinib on cell growth and apoptosis pathway such as ERK1/2 and PI3K/Akt/mTOR. This combination also blocked the activation of EGFR and c-Met which have cross-talk with each other. Unlike in gefitinib-resistant NSCLC cells, MTE alone also demonstrated certain unexpected modulation on EGFR related cell signal pathways in the sensitive cells.
CONCLUSION: Our results suggest that MTE is a promising herbal medicine to improve gefitinib efficacy in NSCLC regardless of EGFR status. However, why MTE acted differently between gefitinib-sensitive and -resistant NSCLC cells needs a further research.

Li J, Zhang L, Gao Z, et al.
Dual inhibition of EGFR at protein and activity level via combinatorial blocking of PI4KIIα as anti-tumor strategy.
Protein Cell. 2014; 5(6):457-68 [PubMed] Free Access to Full Article Related Publications
Our previous studies indicate that phosphatidylinositol 4-kinase IIα can promote the growth of multi-malignant tumors via HER-2/PI3K and MAPK pathways. However, the molecular mechanisms of this pathway and its potential for clinical application remain unknown. In this study, we found that PI4KIIα could be an ideal combinatorial target for EGFR treatment via regulating EGFR degradation. Results showed that PI4KIIα knockdown reduced EGFR protein level, and the expression of PI4KIIα shows a strong correlation with EGFR in human breast cancer tissues (r = 0.77, P < 0.01). PI4KIIα knockdown greatly prolonged the effects and decreased the effective dosage of AG-1478, a specific inhibitor of EGFR. In addition, it significantly enhanced AG1478-induced inhibition of tumor cell survival and strengthened the effect of the EGFR-targeting anti-cancer drug Iressa in xenograft tumor models. Mechanistically, we found that PI4KIIα suppression increased EGFR ligand-independent degradation. Quantitative proteomic analysis by stable isotope labeling with amino acids in cell culture (SILAC) and LC-MS/MS suggested that HSP90 mediated the effect of PI4KIIα on EGFR. Furthermore, we found that combined inhibition of PI4KIIα and EGFR suppressed both PI3K/AKT and MAPK/ERK pathways, and resulted in downregulation of multiple oncogenes like PRDX2, FASN, MTA2, ultimately leading to suppression of tumor growth. Therefore, we conclude that combined inhibition of PI4KIIα and EGFR exerts a multiple anti-tumor effect. Dual inhibition of EGFR at protein and activity level via combinatorial blocking of PI4KIIα presents a novel strategy to combat EGFR-dependent tumors.

Rahman AF, Korashy HM, Kassem MG
Profiles Drug Subst Excip Relat Methodol. 2014; 39:239-64 [PubMed] Related Publications
Gefitinib (Iressa®) is a selective inhibitor of epidermal growth factor, a growth factor that plays a pivotal role in the control of cell growth, apoptosis, and angiogenesis. Gefitinib is clinically used for the treatment of chemoresistant non-small cell lung cancer patients. Gefitinib is freely soluble in dimethylsulphoxide but slightly soluble in methanol and ethanol. Several methods of gefitinib synthesis are included in this review. UV spectroscopy of gefitinib showed a λmax of approximately 331nm, whereas IR spectroscopy principal peaks were observed at 3400cm(-1) (NH), 2956cm(-1) (CH2, CH, alkyl), 1625cm(-1) (CC, CN), 1500cm(-1) (HCCH, aryl), 1110cm(-1) (CO), 1028cm(-1) (CF). In addition, different analytical methods for determination of gefitinib are also described in this review. Pharmacokinetically, after oral administration, gefitinib is slowly absorbed with bioavailability of approximately 60% in human. Gefitinib is metabolized extensively in the liver into five metabolites by cytochrome P450s, primarily by CYP3A4 and to a lesser extent by CYP3A5 and CYP2D6. Gefitinib is eliminated mainly hepatically with total plasma clearance of 595mL/min after intravenous administration. Most of the adverse effects associated with gefitinib therapy are mild to moderate in severity and are usually reversible and manageable with appropriate intervention, such as diarrhea, dry skin, rash, nausea, and vomiting.

Yang JC, Wu YL, Chan V, et al.
Epidermal growth factor receptor mutation analysis in previously unanalyzed histology samples and cytology samples from the phase III Iressa Pan-ASia Study (IPASS).
Lung Cancer. 2014; 83(2):174-81 [PubMed] Related Publications
OBJECTIVES: Epidermal growth factor receptor (EGFR) mutation testing is standard practice after lung adenocarcinoma diagnosis, and provision of high-quality tumor tissue is ideal. However, there are knowledge gaps regarding the utility of cytology or low tumor content histology samples to establish EGFR mutation status, particularly with regard to the proportion of testing performed using these sample types, and the lack of an established link with efficacy of treatment.
METHODS: The randomized phase III Iressa Pan-ASia Study (IPASS; ClinicalTrials.gov identifier NCT00322452) of first-line gefitinib versus chemotherapy analyzed samples meeting preplanned specifications (n=437 evaluable for EGFR mutation; n=261 mutation-positive). This supplementary analysis assessed tumor content and mutation status of histology (n=99) and cytology samples (n=116) which were previously unanalyzed due to sample quality, type, and tumor content (<100 cells). Objective response rate (ORR) and change in tumor size with gefitinib treatment were assessed.
RESULTS: EGFR mutation testing was successful in 80% and 19% of previously unanalyzed histology and cytology samples, respectively. Mutations were detected in 54 tumors previously described as mutation-unknown (histology, n=45; cytology, n=9). ORRs in mutation-positive cytology (83%) and histology (74%) subgroups were consistent with previous analyses (71%). Tumor size decrease was consistent across previously analyzed and unanalyzed samples (all mutation subgroups), with less consistency across ORRs in mutation-negative cytology (16%) and histology (25%) subgroups versus the previous analysis (1%).
CONCLUSIONS: Histology samples with low tumor content and cytology samples can be used for EGFR mutation testing; patients whose mutation status was confirmed using these sample types achieved a response to treatment consistent with those confirmed using high-quality histology samples. Better sample quantity/quality can potentially reduce false-negative results.

Wu W, Yang Q, Fung KM, et al.
Linking γ-aminobutyric acid A receptor to epidermal growth factor receptor pathways activation in human prostate cancer.
Mol Cell Endocrinol. 2014; 383(1-2):69-79 [PubMed] Related Publications
Neuroendocrine (NE) differentiation has been attributed to the progression of castration-resistant prostate cancer (CRPC). Growth factor pathways including the epidermal growth factor receptor (EGFR) signaling have been implicated in the development of NE features and progression to a castration-resistant phenotype. However, upstream molecules that regulate the growth factor pathway remain largely unknown. Using androgen-insensitive bone metastasis PC-3 cells and androgen-sensitive lymph node metastasis LNCaP cells derived from human prostate cancer (PCa) patients, we demonstrated that γ-aminobutyric acid A receptor (GABA(A)R) ligand (GABA) and agonist (isoguvacine) stimulate cell proliferation, enhance EGF family members expression, and activate EGFR and a downstream signaling molecule, Src, in both PC-3 and LNCaP cells. Inclusion of a GABA(A)R antagonist, picrotoxin, or an EGFR tyrosine kinase inhibitor, Gefitinib (ZD1839 or Iressa), blocked isoguvacine and GABA-stimulated cell growth, trans-phospohorylation of EGFR, and tyrosyl phosphorylation of Src in both PCa cell lines. Spatial distributions of GABAAR α₁ and phosphorylated Src (Tyr416) were studied in human prostate tissues by immunohistochemistry. In contrast to extremely low or absence of GABA(A)R α₁-positive immunoreactivity in normal prostate epithelium, elevated GABA(A)R α₁ immunoreactivity was detected in prostate carcinomatous glands. Similarly, immunoreactivity of phospho-Src (Tyr416) was specifically localized and limited to the nucleoli of all invasive prostate carcinoma cells, but negative in normal tissues. Strong GABAAR α₁ immunoreactivity was spatially adjacent to the neoplastic glands where strong phospho-Src (Tyr416)-positive immunoreactivity was demonstrated, but not in adjacent to normal glands. These results suggest that the GABA signaling is linked to the EGFR pathway and may work through autocrine or paracine mechanism to promote CRPC progression.

Mariano C, Bosdet I, Karsan A, et al.
A population-based review of the feasibility of platinum-based combination chemotherapy after tyrosine kinase inhibition in EGFR mutation positive non-small cell lung cancer patients with advanced disease.
Lung Cancer. 2014; 83(1):73-7 [PubMed] Related Publications
INTRODUCTION: The IPASS trial demonstrated superior progression free survival for Asian, light/never smoking, advanced, pulmonary adenocarcinoma patients treated with first-line gefitinib compared to carboplatin/paclitaxel, of which 59% of those tested were epidermal growth factor receptor (EGFR) mutation positive. In IPASS 39% of gefitinib treated patients went on to receive platin based polychemotherapy. We hypothesized that in a population-based setting fewer patients receive second-line platin based chemotherapy than those enrolled in a clinical trial.
METHODS: The Iressa Alliance program provided standardized EGFR mutation testing and appropriate access to gefitinib to all patients in British Columbia with advanced, non squamous non small cell lung cancer (NSCLC). We retrospectively analyzed clinical, pathologic data and outcomes for all patients tested in this program between March 2010 and June 2011.
RESULTS: A total of 548 patients were referred for testing and 22% of patients were mutation positive. Baseline characteristics of mutation negative and mutation positive; median age 67/65, male 41%/31%, Asian 15%/51%, never smoker 21%/58%, stage IV 80%/91%. Median overall survival was 12 months in mutation negative patients and not yet reached in mutation positive (p<0.0001). In mutation positive patients 5% of patients had a complete response, 46% partial response, 34% stable disease, 6% progressive disease. Twenty percent of patients continued on gefitinib after radiographic progression and clinical stability. Sixty-one gefitinib treated patients progressed at the time of analysis; 10% of patients received further gefitinib only, 38% platinum based doublet, 8% other chemotherapy and 44% no further treatment. Performance status most strongly predicted for delivery of second line chemotherapy.
CONCLUSIONS: This North American population based study shows similar efficacy of gefitinib in mutation positive patients compared to the IPASS trial. Contrary to our hypothesis, delivery of second line chemotherapy was feasible in a significant proportion of gefitinib treated patients.

Dragowska WH, Weppler SA, Wang JC, et al.
Induction of autophagy is an early response to gefitinib and a potential therapeutic target in breast cancer.
PLoS One. 2013; 8(10):e76503 [PubMed] Free Access to Full Article Related Publications
Gefitinib (Iressa(®), ZD1839) is a small molecule inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase. We report on an early cellular response to gefitinib that involves induction of functional autophagic flux in phenotypically diverse breast cancer cells that were sensitive (BT474 and SKBR3) or insensitive (MCF7-GFPLC3 and JIMT-1) to gefitinib. Our data show that elevation of autophagy in gefitinib-treated breast cancer cells correlated with downregulation of AKT and ERK1/2 signaling early in the course of treatment. Inhibition of autophagosome formation by BECLIN-1 or ATG7 siRNA in combination with gefitinib reduced the abundance of autophagic organelles and sensitized SKBR3 but not MCF7-GFPLC3 cells to cell death. However, inhibition of the late stage of gefitinib-induced autophagy with hydroxychloroquine (HCQ) or bafilomycin A1 significantly increased (p<0.05) cell death in gefitinib-sensitive SKBR3 and BT474 cells, as well as in gefitinib-insensitive JIMT-1 and MCF7-GFPLC3 cells, relative to the effects observed with the respective single agents. Treatment with the combination of gefitinib and HCQ was more effective (p<0.05) in delaying tumor growth than either monotherapy (p>0.05), when compared to vehicle-treated controls. Our results also show that elevated autophagosome content following short-term treatment with gefitinib is a reversible response that ceases upon removal of the drug. In aggregate, these data demonstrate that elevated autophagic flux is an early response to gefitinib and that targeting EGFR and autophagy should be considered when developing new therapeutic strategies for EGFR expressing breast cancers.

Végvári Á, Fehniger TE, Rezeli M, et al.
Experimental models to study drug distributions in tissue using MALDI mass spectrometry imaging.
J Proteome Res. 2013; 12(12):5626-33 [PubMed] Related Publications
Requirements for patient safety and improved efficacy are steadily increasing in modern healthcare and are key drivers in modern drug development. New drug characterization assays are central in providing evidence of the specificity and selectivity of drugs. Meeting this need, matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) is used to study drug localization within microenvironmental tissue compartments. Thin sections of human lung tumor and rat xenograft tissues were exposed to pharmaceutical drugs by either spotting or submerging. These drugs, the epidermal growth factor receptor antagonists, erlotinib (Tarceva) and gefitinib (Iressa), and the acetylcholine receptor antagonist, tiotropium, were characterized by microenvironment localization. Intact tissue blocks were also immersed in drug solution, followed by sectioning. MALDI-MSI was then performed using a Thermo MALDI LTQ Orbitrap XL instrument to localize drug-distribution patterns. We propose three MALDI-MSI models measuring drug disposition that have been used to map the selected compounds within tissue compartments of tumors isolated from lung cancer patients.

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