R. Perona

IGFBP-3 hypermethylation-derived deficiency mediates cisplatin resistance in non-small-cell lung cancer

Cisplatin-based chemotherapy is the paradigm of non-small-cell lung cancer (NSCLC) treatment; however, it also induces de novo DNA-hypermethylation, a process that may be involved in the development of drug-resistant phenotypes by inactivating genes required for drug-cytotoxicity. By using an expression microarray analysis, we aimed to identify those genes reactivated in a set of two cisplatin (CDDP) resistant and sensitive NSCLC cell lines after epigenetic treatment. Gene expression, promoter methylation and CDDP-chemoresponse were further analyzed in three matched sets of sensitive/resistant cell lines, 23 human cancer cell lines and 36 NSCLC specimens. Results revealed specific silencing by promoter hypermethylation of IGFBP-3 in CDDP resistant cells, whereas IGFBP-3 siRNA interference, induced resistance to CDDP in sensitive cells (P<0.001). In addition, we found a strong correlation between methylation status and CDDP response in tumor specimens (P<0.001). Thus, stage I patients, whose tumors harbor an unmethylated promoter, had a trend towards increased disease-free survival (DFS). We report that a loss of IGFBP-3 expression, mediated by promoter-hypermethylation, results in a reduction of tumor cell sensitivity to cisplatin in NSCLC. Basal methylation status of IGFBP-3 before treatment may be a clinical biomarker and a predictor of the chemotherapy outcome, helping to identify patients who are most likely to benefit from CDDP therapy alone or in combination with epigenetic treatment.

MKP1/CL100 controls tumor growth and sensitivity to cisplatin in non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) represents the most frequent and therapy-refractive sub-class of lung cancer. Improving apoptosis induction in NSCLC represents a logical way forward in treating this tumor. Cisplatin, a commonly used therapeutic agent in NSCLC, induces activation of N-terminal-c-Jun kinase (JNK) that, in turn, mediates induction of apoptosis. In analysing surgical tissue samples of NSCLC, we found that expression of MKP1/CL100, a negative regulator of JNK, showed a strong nuclear staining for tumor cells, whereas, in normal bronchial epithelia, MKP1 was localized in the cytoplasm as well as in nuclei. In the NSCLC-derived cell lines H-460 and H-23, we found that MKP1 was constitutively expressed. Expressing a small-interfering RNA (siRNA) vector for MKP1 in H-460 cells resulted in a more efficient activation by cisplatin of JNK and p38 than in the parental cells, and this correlated with a 10-fold increase in sensitivity to cisplatin. A similar response was also observed in H-460 and H-23 cells when treated with the MKP1 expression inhibitor RO-31-8220. Moreover, expression of a siRNA-MKP2, an MKP1-related phosphatase, had no effect on H-460 cell viability response to cisplatin. Tumors induced by H-460 cells expressing MKP1 siRNA grew slower in nu−/nu− mice and showed more susceptibility to cisplatin than parental cells, and resulted in an impaired growth of the tumor in mice. On the other hand, overexpression of MKP1 in the H-1299 NSCLC-derived cell line resulted in further resistance to cisplatin. Overall, the results showed that inhibition of MKP1 expression contributes to a slow down in cell growth in mice and an increase of cisplatin-induced cell death in NSCLC. As such, MKP1 can be an attractive target in sensitizing cells to cisplatin to increase the effectiveness of the drug in treating NSCLC.

IGFBP-3 methylation-derived deficiency mediates the resistance to cisplatin through the activation of the IGFIR/Akt pathway in non-small cell lung cancer.

Although many cancers initially respond to cisplatin (CDDP)-based chemotherapy, resistance frequently develops. Insulin-like growth factor-binding protein-3 (IGFBP-3) silencing by promoter methylation is involved in the CDDP-acquired resistance process in non-small cell lung cancer (NSCLC) patients. Our purpose is to design a translational-based profile to predict resistance in NSCLC by studying the role of IGFBP-3 in the phosphatidyl inositol 3-kinase (PI3K) signaling pathway. We have first examined the relationship between IGFBP-3 expression regulated by promoter methylation and activation of the epidermal growth factor receptor (EGFR), insulin-like growth factor-I receptor (IGFIR) and PI3K/AKT pathways in 10 human cancer cell lines and 25 NSCLC patients with known IGFBP-3 methylation status and response to CDDP. Then, to provide a helpful tool that enables clinicians to identify patients with a potential response to CDDP, we have calculated the association between our diagnostic test and the true outcome of analyzed samples in terms of cisplatin IC50; the inhibitory concentration that kills 50% of the cell population. Our results suggest that loss of IGFBP-3 expression by promoter methylation in tumor cells treated with CDDP may activate the PI3K/AKT pathway through the specific derepression of IGFIR signaling, inducing resistance to CDDP. This study also provides a predictive test for clinical practice with an accuracy and precision of 0.84 and 0.9, respectively, (P=0.0062). We present a biomarker test that could provide clinicians with a robust tool with which to decide on the use of CDDP, improving patient clinical outcomes.

Treatment for ALK-mutated non-small-cell lung cancer: a new miracle in the research race

The discovery of anaplastic lymphoma kinase (ALK) rearrangements in a subset of patients with non-small-cell lung cancer (NSCLC) and its potential blockage by specific inhibitors such as crizotinib has been one of the latest advances in the treatment of this disease. In this article, we will review the most important clinical aspects of ALK alterations in NSCLC patients and the pending questions to answer: the most effective means of diagnosing ALK-rearranged NSCLC, and efficacy, toxicity profile and potential mechanisms of resistance to crizotinib.

Acortamiento de los telómeros en fibrosis pulmonar idiopática

a Unidad Funcional de Intersticio Pulmonar (UFIP), Servicio de Neumología, Hospital Universitario de Bellvitge, IDIBELL, L’Hospitalet de Llobregat, Barcelona, Spain b Centro de Investigación en Red de Enfermedades Respiratorias (CIBERES), Spain c Instituto de Investigaciones Biomédicas «Alberto Sols», CSIC-UAM, Madrid, Spain d Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain

PCN40 Year to Year Budget Impact Analysis of Biological Therapies for First-Line Treatment of Metastatic Colorectal Cancer in Spain

Martinez-Amores B1, Mezquita L2, Ibanez de Caceres I3, Ayuso A2, Pena JM4, Perona R3, Grande E5, Belda-Iniesta C6 1Hospital Rey Juan Carlos, Madrid, Spain, 2Centro Integral Oncologico Clara Campal (CIOCC), Madrid, Spain, 3IdiPAZ, Madrid, Spain, 4School of Informatics. UPM, Madrid, Spain, 5Hospital Universitario Ramon y Cajal, Madrid, Spain, 6Centro Integral Oncologico Clara Campal (CIOCC), Madrid, Madrid, Spain OBJECTIVES: In real practice, patients are treated along the entire year so that budget simulations should be adjusted to chronological patterns of oncological assistance. Deferred budget impact analysis is undergone in order to assess longrun economic implications of clinical decisions on first-line mCRC therapies in Spain. METHODS: As metastatic colorectal cancer diagnosis is not affected by seasonal influences, we have created a mathematical model assuming that a single patient is diagnosed every month and this patient has a 53% possibility to harbor a native K-Ras sequence. Calculi were arranged based on median duration of therapy. For bevacizumab-based therapy, budget impact for year t 1 begins at month 5 and beyond. For patients that receive cetuximab-based therapy, budget impact for year t 1 begins at month 7. The same approach was performed for doublets without any monoclonal antibody. Prices for all drugs in Spain were assumed to represent the best-value for each drug including all possibilities to reduce pharmacy costs. For first line, median duration of therapy reported by randomized trials was used to calculate the final budget. 70kg and 1.7 m were used as reference for patient dose calculations. RESULTS: When K-Ras status is not tested and bevacizumab-based schedules are administered to every patient, annual growth of budget increases by 55-60%. If K-Ras status is analyzed and wild-type patients are treated with cetuximab combinations and mutated patients receive bevacizumab, yearly budget growth amounts to 39-41%. Annual budget growth is minimized (25%) when K-Ras wt patients are treated with cetuximab combinations whereas K-Ras mutated tumours received chemotherapy alone. CONCLUSIONS: Duration of therapy plays a key role on budget impact estimations from both overall and year to year perspectives. K-Ras based clinical decisions not only optimize outcomes as measured by response rates but also minimize economic implications on annual budget growths.

199 IGFBP-3 promoter methylation activates the PI3K/Akt intracellular signaling pathway in CDDP resistant cell lines

Trabajo presentado al 21th Meeting of the European Association for Cancer Research celebrado en Bruselas (Belgica) del 25 de Junio al 30 de Junio de 2010.