Samir E. Witta

Restoring E-cadherin expression increases sensitivity to epidermal growth factor receptor inhibitors in lung cancer cell lines.

The epidermal growth factor receptor (EGFR) is overexpressed in the majority of non-small cell lung cancers (NSCLC). EGFR tyrosine kinase inhibitors, such as gefitinib and erlotinib, produce 9% to 27% response rates in NSCLC patients. E-Cadherin, a calcium-dependent adhesion molecule, plays an important role in NSCLC prognosis and progression, and interacts with EGFR. The zinc finger transcriptional repressor, ZEB1, inhibits E-cadherin expression by recruiting histone deacetylases (HDAC). We identified a significant correlation between sensitivity to gefitinib and expression of E-cadherin, and ZEB1, suggesting their predictive value for responsiveness to EGFR-tyrosine kinase inhibitors. E-Cadherin transfection into a gefitinib-resistant line increased its sensitivity to gefitinib. Pretreating resistant cell lines with the HDAC inhibitor, MS-275, induced E-cadherin along with EGFR and led to a growth-inhibitory and apoptotic effect of gefitinib similar to that in gefitinib-sensitive NSCLC cell lines including those harboring EGFR mutations. Thus, combined HDAC inhibitor and gefitinib treatment represents a novel pharmacologic strategy for overcoming resistance to EGFR inhibitors in patients with lung cancer.

Baseline Gene Expression Predicts Sensitivity to Gefitinib in Non–Small Cell Lung Cancer Cell Lines

Tyrosine kinase inhibitors (TKI) of the epidermal growth factor receptor (EGFR) produce objective responses in a minority of patients with advanced-stage non–small cell lung cancer (NSCLC), and about half of all treated patients progress within 6 weeks of instituting therapy. Because the target of these agents is known, it should be possible to develop biological predictors of response, but EGFR protein levels have not been proven useful as a predictor of TKI response in patients and the mechanism of primary resistance is unclear. We used microarray gene expression profiling to uncover a pattern of gene expression associated with sensitivity to EGFR-TKIs by comparing NSCLC cell lines that were either highly sensitive or highly resistant to gefitinib. This sensitivity-associated expression profile was used to predict gefitinib sensitivity in a panel of NSCLC cell lines with known gene expression profiles but unknown gefitinib sensitivity. Gefitinib sensitivity was then determined for members of this test panel, and the microarray-based sensitivity prediction was correct in eight of nine NSCLC cell lines. Gene and protein expression differences were confirmed with a combination of quantitative reverse transcription-PCR, flow cytometry, and immunohistochemistry. This gene expression pattern related to gefitinib sensitivity was independent from sensitivity associated with EGFR mutations. Several genes associated with sensitivity encode proteins involved in HER pathway signaling or pathways that interrelate to the HER signaling pathway. Some of these genes could be targets of pharmacologic interventions to overcome primary resistance. (Mol Cancer Res 2006;4(8):521–8)

Randomized Phase II Trial of Erlotinib With and Without Entinostat in Patients With Advanced Non–Small-Cell Lung Cancer Who Progressed on Prior Chemotherapy

PURPOSE Histone deacetylase inhibitors (HDACis) have been shown to overcome resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) linked to epigenetic changes and epithelial-mesenchymal transition (EMT) state. This randomized phase II study evaluated the outcome of erlotinib with and without the isoform selective HDACi, entinostat. PATIENTS AND METHODS Previously treated patients with stage IIIB/IV non-small-cell lung cancer, no prior EGFR-TKIs, and performance status ≤ 2 were randomly administered erlotinib 150 mg on days 1 through 28 plus entinostat 10 mg orally on days 1 and 15 every 28 days (EE) or erlotinib plus placebo (EP). The primary end point was 4-month progression-free survival (PFS) rate with additional end points including 6-month PFS rate, PFS, and overall survival (OS). Exploratory analyses included EMT- and EGFR-related biomarker analysis on archival tissue. RESULTS One hundred thirty-two patients were enrolled (EE, 67; EP, 65). The 4-month PFS rate was comparable for both groups (EE, 18% v EP, 20%; P = .7). In the subset of patients with high E-cadherin levels, OS was longer in the EE group compared with the EP group (9.4 v 5.4 months; hazard ratio, 0.35; 95% CI, 0.13 to 0.92; P = .03) with a corresponding trend toward increased PFS. The adverse event (AE) profile was acceptable, with rash, fatigue, diarrhea, and nausea the most common AEs in both groups. CONCLUSION Erlotinib combined with entinostat did not improve the outcomes of patients in the overall study population when compared with erlotinib monotherapy. High E-cadherin expression levels at time of diagnosis indicate an increased sensitivity to HDACi/EGFR-TKI inhibition providing the basis for a biomarker-driven validation study.

Insulin-like Growth Factor Receptor 1 (IGF1R) Gene Copy Number Is Associated With Survival in Operable Non–Small-Cell Lung Cancer: A Comparison Between IGF1R Fluorescent In Situ Hybridization, Protein Expression, and mRNA Expression

PURPOSE The purpose of this study was to characterize insulin-like growth factor-1 receptor (IGF1R) protein expression, mRNA expression, and gene copy number in surgically resected non-small-cell lung cancers (NSCLC) in relation to epidermal growth factor receptor (EGFR) protein expression, patient characteristics, and prognosis. PATIENTS AND METHODS One hundred eighty-nine patients with NSCLC who underwent curative pulmonary resection were studied (median follow-up, 5.3 years). IGF1R protein expression was evaluated by immunohistochemistry (IHC) with two anti-IGF1R antibodies (n = 179). EGFR protein expression was assessed with PharmDx kit. IGF1R gene expression was evaluated using quantitative reverse transcription polymerase chain reaction (qRT-PCR) from 114 corresponding fresh-frozen samples. IGF1R gene copy number was assessed by fluorescent in situ hybridization using customized probes (n = 181). RESULTS IGF1R IHC score was higher in squamous cell carcinomas versus other histologies (P < .001) and associated with stage (P = .03) but not survival (P = .46). IGF1R and EGFR protein expression showed significant correlation (r = 0.30; P < .001). IGF1R gene expression by qRT-PCR was higher in squamous cell versus other histologies (P = .006) and did not associate with other clinical features nor survival (P = .73). Employing criteria previously established for EGFR copy number, patients with IGF1R amplification/high polysomy (n = 48; 27%) had 3-year survival of 58%, patients with low polysomy (n = 87; 48%) had 3-year survival of 47% and patients with trisomy/disomy (n = 46; 25%) had 3-year survival of 35%, respectively (P = .024). Prognostic value of high IGF1R gene copy number was confirmed in multivariate analysis. CONCLUSION IGF1R protein expression is higher in squamous cell versus other histologies and correlates with EGFR expression. IGF1R protein and gene expression does not associate with survival, whereas high IGF1R gene copy number harbors positive prognostic value.

Epidermal Growth Factor Receptor Messenger RNA Expression, Gene Dosage, and Gefitinib Sensitivity in Non–Small Cell Lung Cancer

Purpose: Epidermal growth factor receptor (EGFR) mRNA expression and EGFR gene dosage by quantitative PCR in tumor samples obtained from patients with gefitinib-treated non–small cell lung cancer were analyzed in order to determine the association with treatment outcome, clinical, and biological features [EGFR copy number by fluorescent in situ hybridization (FISH), EGFR tyrosine kinase mutations, and EGFR protein expression]. Experimental Design: EGFR mRNA expression was measured by real-time quantitative reverse transcription-PCR in 64 patients, and EGFR gene dosage was analyzed by real-time quantitative PCR in 82 patients from paraffin-embedded specimens. Results: EGFR mRNA expression was higher in responders to gefitinib as compared with nonresponders (P = 0.012). Patients with high EGFR mRNA expression (>5.01) had 43% response probability, whereas patients with low EGFR mRNA expression had 8% response probability (P = 0.006). Patients with high EGFR mRNA expression had longer median progression-free (5.3 versus 2.8 months, P = 0.028) but not overall survival (13.8 versus 10.9 months, P = 0.87). EGFR mRNA expression was higher in FISH-positive patients (P = 0.001) and in patients with positive EGFR immunostaining (P < 0.001) but not in patients with EGFR mutations (P = 0.19). EGFR gene dosage did not predict response (P = 0.54), progression-free (P = 0.73), or overall survival (P = 0.89). EGFR gene dosage was not associated with FISH positivity (P = 0.15), relative mRNA expression (P = 0.27), EGFR mutation status (P = 0.39), and EGFR protein expression (P = 0.35). Conclusion: EGFR mRNA expression is a predictive biomarker for response to gefitinib and to progression-free survival after gefitinib treatment. EGFR gene dosage is neither predictive for response nor progression-free nor overall survival.

A Phase I Biological and Pharmacologic Study of the Heparanase Inhibitor PI-88 in Patients with Advanced Solid Tumors

Purpose: PI-88 is a mixture of highly sulfated oligosaccharides that inhibits heparanase, an extracellular matrix endoglycosidase, and the binding of angiogenic growth factors to heparan sulfate. This agent showed potent inhibition of placental blood vessel angiogenesis as well as growth inhibition in multiple xenograft models, thus forming the basis for this study. Experimental Design: This study evaluated the toxicity and pharmacokinetics of PI-88 (80-315 mg) when administered s.c. daily for 4 consecutive days bimonthly (part 1) or weekly (part 2). Results: Forty-two patients [median age, 53 years (range, 19-78 years); median performance status, 1] with a range of advanced solid tumors received a total of 232 courses. The maximum tolerated dose was 250 mg/d. Dose-limiting toxicity consisted of thrombocytopenia and pulmonary embolism. Other toxicity was generally mild and included prolongation of the activated partial thromboplastin time and injection site echymosis. The pharmacokinetics were linear with dose. Intrapatient variability was low and interpatient variability was moderate. Both AUC and Cmax correlated with the percent increase in activated partial thromboplastin time, showing that this pharmacodynamic end point can be used as a surrogate for drug exposure. No association between PI-88 administration and vascular endothelial growth factor or basic fibroblast growth factor levels was observed. One patient with melanoma had a partial response, which was maintained for >50 months, and 9 patients had stable disease for ≥6 months. Conclusion: The recommended dose of PI-88 administered for 4 consecutive days bimonthly or weekly is 250 mg/d. PI-88 was generally well tolerated. Evidence of efficacy in melanoma supports further evaluation of PI-88 in phase II trials.

Biological markers for non-small cell lung cancer patient selection for epidermal growth factor receptor tyrosine kinase inhibitor therapy

The selection of patients for tumor-specific therapies using molecular/biological properties of the patients tumor has been a long tradition in breast cancer (e.g., estrogen receptor, progesterone receptor, and HER-2/ neu ) but has not been widely accepted in lung cancer therapy selection ([1][1

Biomarkers for prediction of sensitivity to EGFR inhibitors in non-small cell lung cancer.

Purpose of review Epidermal growth factor receptor (EGFR) Inhibitors have shown promising results in patients with advanced non-small cell lung cancers (NSCLC) who previously have failed on chemotherapy. Objective response is achieved in 10 to 28% of the patients, and about 30% will achieve stable disease. A major problem is how to select the patients, who will benefit from treatment, and who will not. Recent findings The predictive role of EGFR protein expression assessed by IHC is still debated. Specific EGFR gene mutations have been identified associated with response to gefitinib (Iressa®), but seem not to be associated with stable disease. No studies have yet demonstrated any association between EGFR gene mutations and survival. In this review we describe other marker studies, which are associated with sensitivity to EGFR inhibitors. Increased EGFR gene copy number based on FISH analysis is demonstrated to be a good predictive marker for response, stable disease, time to progression, and survival. Summary EGFR/FISH seems today to be the best predictive marker for clinical benefit from EGFR inhibitors in NSCLC. Prospective large scale clinical studies must identify the most optimal paradigm for selection of patients.

A Phase I and Pharmacokinetic Study of Exisulind and Docetaxel in Patients with Advanced Solid Tumors

Purpose: Exisulind (sulindac sulfone, FGN-1, Aptosyn) is a sulindac metabolite that induces apoptosis via inhibition of cyclic GMP-phosphodiesterase. This agent demonstrated tumor growth inhibition in rodent models of colon, breast, prostate, and lung carcinogenesis. In an orthotopic model of human non–small-cell lung cancer, the combination of exisulind and docetaxel prolonged survival in athymic nude rats, forming the basis of this phase I combination study. Experimental Design: This study evaluated the toxicity and pharmacokinetics of combining exisulind (150–250 mg) given orally twice daily and docetaxel (30–36 mg/m2) administered intravenously on days 1, 8, and 15 of a 4-week cycle. Results: Twenty patients with a range of advanced solid tumors (median age, 59 years; age range, 35–77 years; median performance status, 1) received a total of 70 courses. Observed adverse events were mild to moderate, and there was no dose-limiting toxicity at any level. Grade 3 gastrointestinal toxicities were present in 10 of the 70 cycles (10%) and included nausea, vomiting, dyspepsia, and elevated alkaline phosphatase. Neutropenia was present in four cycles in patients treated with a docetaxel dose of 36 mg/m2. Pharmacokinetic analysis did not demonstrate a clear effect of exisulind on docetaxel pharmacokinetics and vice versa. Relationships were evident between the plasma concentration of exisulind and the development of grade 2 or greater toxicities. One third of patients maintained stable disease for 3 to 12 cycles, but no objective responses were observed. Conclusions: The combination of docetaxel (36 mg/m2, weekly) and exisulind (500 mg/d) was reasonably well tolerated, and it is undergoing phase II testing in patients with non–small-cell lung cancer.

Abstract 5439: Characterization of the class 1 histone deacetylase inhibitor entinostat in EGFRi acquired resistance models and in combination with cetuximab in NSCLC

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Background: Entinostat is a novel oral benzamide HDACi characterized by its selectivity for class 1 HDACs as well as a unique pharmacokinetic (PK) and pharmacodynamic (PD) profile. Previous results have demonstrated the ability of entinostat to synergize in vitro and in vivo with the small molecule EGFR inhibitors, gefitinib and erlotinib as well as EGFR directed antibody, cetuximab to inhibit growth of EGFRi resistant NSCLC cells. The mechanism for the combined efficacy may involve a) targeting of EGFR gene and protein expression b) down-regulation of EGFR-mediated signal transduction pathway c) alteration of the tumor phenotype to re-sensitize cancer cells to EGFRi. Methods: The growth inhibitory effect of the combination of erlotinib and entinostat in H1975 and H1933 cells was determined using a 5-day 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. In vivo efficacy of entinostat was tested in athymic nude mice bearing NSCLC xenografts, A549 and H460. Combined treatment of entinostat with cetuximab was studied in H460 xenografts Results: We have extended our previous work examining the effect of entinostat on EGFRi resistance through testing of entinostat combined with erlotinib in cell line models of acquired resistance and evaluating the combination of entinostat with cetuximab in vivo in a xenograft model. Our results demonstrate that the combination of entinostat and erlotinib has enhanced activity in H1975 NSCLC cells which harbor the EGFRi T790M mutation. In addition the combination is more effective in H1933 NSCLC cells which have a met amplification. To further characterize the potential mechanism of action by which entinostat sensitizes NSCLC cells to EGFRi we have also tested entinostat in vivo in A549 and H460 xenograft models. Entinostat exhibits a dose response inhibition of tumor growth in both models and analysis of molecular markers is ongoing. In our previous experiments examining impact of entinostat on EGFRi resistance we reported on the combined efficacy of entinostat and cetuximab in the A549 NSCLC xenograft model. We have followed up on those initial findings through testing in a second xenograft model (H460) and will report those results. Conclusions: Entinostat enhances the effect of EGFR inhibitors in models of acquired EGFR resistance. The results from these experiments support the rationale of combining HDACi and EGFRi (small molecules as well as antibodies) in clinical studies in NSCLC. Ongoing clinical trials testing these hypothesis include ENCORE-401, a randomized, placebo controlled phase 2 study of erlotinib +/− entinostat in NSCLC patients and a pilot study, ENCORE-403 which was initiated to test the effect of entinostat on resistance to the EGFRi erlotinib in NSCLC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5439.