Regorafenib monotherapy as second-line treatment of patients with RAS-mutant advanced colorectal cancer (STREAM): an academic, multicenter, single-arm, two-stage, phase II study.

BACKGROUND: Maintaining angiogenesis inhibition and switching the chemotherapy backbone represent the current second-line therapy in patients with RAS-mutant metastatic colorectal cancer (mCRC). Regorafenib, an oral multikinase inhibitor, prolonged overall survival (OS) in the chemorefractory setting. MATERIALS AND METHODS: STREAM was an academic, multicenter, single-arm phase II trial, evaluating the activity of regorafenib in RAS-mutant mCRC, in terms of the rate of patients who were progression-free after 6 months from study entry (6mo-PF). Patients were pretreated with fluoropyrimidine, oxaliplatin, and bevacizumab. According to Simon's two-stage design, ≥18 patients 6mo-PF were needed in the overall population (N = 46). Secondary endpoints were safety, objective response rate (ORR), progression-free survival (PFS), and OS. Early metabolic response by [18F]2-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography ([18F]-FDG PET/CT) scan was an exploratory endpoint. EudraCT Number: 2015-001105-13. RESULTS: The number of patients 6mo-PF was 8/22 at the first stage and 14/46 in the overall population. The ORR was 10.9%, disease control rate was 54.6%, median (m)PFS was 3.6 months [95% confidence interval (CI) 1.9-6.7 months], mOS was 18.9 months (95% CI 10.3-35.3 months), and mPFS2 (from study entry to subsequent-line progression) was 13.3 months (95% CI 8.4-19.7 months). Long benefiter patients (>6mo-PF) significantly more often had a single metastatic site and lung-limited disease. No unexpected toxicity was reported. Grade ≥3 events occurred in 39.1% of patients, with hand-foot syndrome (13%), fatigue, and hyperbilirubinemia (6.5%) occurring mostly. Baseline metabolic assessment was associated with OS in the multivariate analysis, while early metabolic response was not associated with clinical outcomes. CONCLUSIONS: The study did not meet its primary endpoint. However, regorafenib was well tolerated and did not preclude subsequent treatments. Patients with good prognostic features (single metastatic site and lung-limited disease) reported clinical benefit with regorafenib. The exploratory metabolic analysis suggests that baseline [18F]-FDG PET/CT might be useful to select patients with a favorable outcome. A chemotherapy-free interval with regorafenib was associated with durable disease control in a selected group of patients with favorable clinical characteristics.

Transition from a uni- to a bimodal interfacial charge distribution in [Formula: see text]/[Formula: see text] upon cooling.

We present a combined resonant soft X-ray reflectivity and electric transport study of [Formula: see text]/[Formula: see text] field effect devices. The depth profiles with atomic layer resolution that are obtained from the resonant reflectivity reveal a pronounced temperature dependence of the two-dimensional electron liquid at the [Formula: see text]/[Formula: see text] interface. At room temperature the corresponding electrons are located close to the interface, extending down to 4 unit cells into the [Formula: see text] substrate. Upon cooling, however, these interface electrons assume a bimodal depth distribution: They spread out deeper into the [Formula: see text] and split into two distinct parts, namely one close to the interface with a thickness of about 4 unit cells and another centered around 9 unit cells from the interface. The results are consistent with theoretical predictions based on oxygen vacancies at the surface of the [Formula: see text] film and support the notion of a complex interplay between structural and electronic degrees of freedom.

SNORD116 deletions cause Prader-Willi syndrome with a mild phenotype and macrocephaly.

Prader-Willi syndrome is a complex condition caused by lack of expression of imprinted genes in the paternally derived region of chromosome 15 (15q11q13). A small number of patients with Prader-Willi phenotype have been discovered to have narrow deletions, not encompassing the whole critical region, but only the SNORD116 cluster, which includes genes codifying for small nucleolar RNAs. This kind of deletion usually is not detected by the classic DNA methylation analysis test. We present the case of a male patient with a mild Prader-Willi phenotype and a small deletion including SNORD116, diagnosed by methylation-sensitive multiplex ligation-dependent probe amplification (MLPA. The patient showed neonatal hypotonia, hyperphagia, obesity, central hypogonadism, hypothyroidism, strabismus. Stature and intellectual development are within the normal range. The presence of macrocephaly, observed in other cases of SNORD116 deletions as well, is uncommon for the classic phenotype of the syndrome.

Tunable spin polarization and superconductivity in engineered oxide interfaces.

Advances in growth technology of oxide materials allow single atomic layer control of heterostructures. In particular delta doping, a key materials' engineering tool in today's semiconductor technology, is now also available for oxides. Here we show that a fully electric-field-tunable spin-polarized and superconducting quasi-2D electron system (q2DES) can be artificially created by inserting a few unit cells of delta doping EuTiO3 at the interface between LaAlO3 and SrTiO3 oxides. Spin polarization emerges below the ferromagnetic transition temperature of the EuTiO3 layer (TFM = 6-8 K) and is due to the exchange interaction between the magnetic moments of Eu-4f and of Ti-3d electrons. Moreover, in a large region of the phase diagram, superconductivity sets in from a ferromagnetic normal state. The occurrence of magnetic interactions, superconductivity and spin-orbit coupling in the same q2DES makes the LaAlO3/EuTiO3/SrTiO3 system an intriguing platform for the emergence of novel quantum phases in low-dimensional materials.

Panobinostat synergizes with zoledronic acid in prostate cancer and multiple myeloma models by increasing ROS and modulating mevalonate and p38-MAPK pathways.

Patients with advanced prostate cancer (PCa) and multiple myeloma (MM) have limited long-term responses to available therapies. The histone deacetylase inhibitor panobinostat has shown significant preclinical and clinical anticancer activity in both hematological and solid malignancies and is currently in phase III trials for relapsed MM. Bisphosphonates (BPs), such as zoledronic acid (ZOL), inhibit osteoclast-mediated bone resorption and are indicated for the treatment of bone metastasis. BPs, including ZOL, have also shown anticancer activity in several preclinical and clinical studies. In the present report, we found a potent synergistic antiproliferative effect of panobinostat/ZOL treatment in three PCa and three MM cell lines as well as in a PCa ZOL-resistant subline, independently of p53/KRAS status, androgen dependency, or the schedule of administration. The synergistic effect was also observed in an anchorage-independent agar assay in both ZOL-sensitive and ZOL-resistant cells and was confirmed in vivo in a PCa xenograft model. The co-administration of the antioxidant N-acetyl-L-cysteine blocked the increased reactive oxygen species generation and apoptosis observed in the combination setting compared with control or single-agent treatments, suggesting that oxidative injury plays a functional role in the synergism. Proapoptotic synergy was also partially antagonized by the addition of geranyl-geraniol, which bypasses the inhibition of farnesylpyrophosphate synthase by ZOL in the mevalonate pathway, supporting the involvement of this pathway in the synergy. Finally, at the molecular level, the inhibition of basal and ZOL-induced activation of p38-MAPK by panobinostat in sensitive and ZOL-resistant cells and in tumor xenografts could explain, at least in part, the observed synergism.

Reduction of maternal mortality with highly active antiretroviral therapy in a large cohort of HIV-infected pregnant women in Malawi and Mozambique.

BACKGROUND: HIV infection is a major contributor to maternal mortality in resource-limited settings. The Drug Resource Enhancement Against AIDS and Malnutrition Programme has been promoting HAART use during pregnancy and postpartum for Prevention-of-mother-to-child-HIV transmission (PMTCT) irrespective of maternal CD4 cell counts since 2002. METHODS: Records for all HIV+ pregnancies followed in Mozambique and Malawi from 6/2002 to 6/2010 were reviewed. The cohort was comprised by pregnancies where women were referred for PMTCT and started HAART during prenatal care (n = 8172, group 1) and pregnancies where women were referred on established HAART (n = 1978, group 2). RESULTS: 10,150 pregnancies were followed. Median (IQR) baseline values were age 26 years (IQR:23-30), CD4 count 392 cells/mm(3) (IQR:258-563), Viral Load log10 3.9 (IQR:3.2-4.4), BMI 23.4 (IQR:21.5-25.7), Hemoglobin 10.0 (IQR: 9.0-11.0). 101 maternal deaths (0.99%) occurred during pregnancy to 6 weeks postpartum: 87 (1.1%) in group 1 and 14 (0.7%) in group 2. Mortality was 1.3% in women with

Acquired resistance to zoledronic acid and the parallel acquisition of an aggressive phenotype are mediated by p38-MAP kinase activation in prostate cancer cells.

The nitrogen-containing bisphosphonates (N-BP) zoledronic acid (ZOL) inhibits osteoclast-mediated bone resorption, and it is used to prevent skeletal complications from bone metastases. ZOL has also demonstrated anticancer activities in preclinical models and, recently, in cancer patients, highlighting the interest in determining eventual mechanisms of resistance against this agent. In our study, we selected and characterised a resistant subline of prostate cancer (PCa) cells to better understand the mechanisms, by which tumour cells can escape the antitumour effect of ZOL. DU145R80-resistant cells were selected in about 5 months using stepwise increasing concentrations of ZOL from DU145 parental cells. DU145R80 cells showed a resistance index value of 5.5 and cross-resistance to another N-BP, pamidronate, but not to the non-nitrogen containing BP clodronate. Notably, compared with DU145 parental cells, DU145R80 developed resistance to apoptosis and anoikis, as well as overexpressed the anti-apoptotic protein Bcl-2 and oncoprotein c-Myc. Moreover, DU145R80 cells underwent epithelial to mesenchymal transition (EMT) and showed increased expression of the metalloproteases MMP-2/9, as well as increased invading capability. Interestingly, compared with DU145, DU145R80 cells also increased the gene expression and protein secretion of VEGF and the cytokines Eotaxin-1 and IL-12. At the molecular level, DU145R80 cells showed strong activation of the p38-MAPK-dependent survival pathway compared with parental sensitive cells. Moreover, using the p38-inhibitor SB203580, we completely reversed the resistance to ZOL, as well as EMT marker expression and invasion. Furthermore, SB203580 treatment reduced the expression of VEGF, Eotaxin-1, IL-12, MMP-9, Bcl-2 and c-Myc. Thus, for the first time, we demonstrate that the p38-MAPK pathway can be activated under continuous extensive exposure to ZOL in PCa cells and that the p38-MAPK pathway has a critical role in the induction of resistance, as well as in the acquisition of a more aggressive and invasive phenotype.

A systematic review of the literature concerning the relationship between obesity and mortality in the elderly.

INTRODUCTION: Obesity is a risk factor for chronic diseases and premature mortality, but the extent of these associations among the elderly is under debate. The aim of this systematic literature review (SR) is to collate and critically assess the available information of the impact of obesity on mortality in the elderly. METHODS: In PubMed, there are three-hundred twelve papers on the relationship between obesity and mortality among older adults. These papers were analysed on the basis of their abstracts, and sixteen studies were considered suitable for the purpose of the study. It was possible to perform a pooled estimate for aggregated data in three different studies. CONCLUSION: The results of this SR document that an increased mortality in obese older adults. The limitation of BMI to index obesity and the noted protective action of a moderate increase in BMI on mortality are highlighted. Waist circumference is an indicator of central adiposity and potentially as good a risk factor for mortality as BMI in obese elderly adults.

Vorinostat synergises with capecitabine through upregulation of thymidine phosphorylase.

BACKGROUND: Potentiation of anticancer activity of capecitabine is required to improve its therapeutic index. In colorectal cancer (CRC) cells, we evaluated whether the histone deacetylase-inhibitor vorinostat may induce synergistic antitumour effects in combination with capecitabine by modulating the expression of thymidine phosphorylase (TP), a key enzyme in the conversion of capecitabine to 5-florouracil (5-FU), and thymidylate synthase (TS), the target of 5-FU. METHODS: Expression of TP and TS was measured by real-time PCR, western blotting and immunohistochemistry. Knockdown of TP was performed by specific small interfering RNA. Antitumour activity of vorinostat was assessed in vitro in combination with the capecitabine active metabolite deoxy-5-fluorouridine (5'-DFUR) according to the Chou and Talay method and by evaluating apoptosis as well as in xenografts-bearing nude mice in combination with capecitabine. RESULTS: Vorinostat induced both in vitro and in vivo upregulation of TP as well as downregulation of TS in cancer cells, but not in ex vivo treated peripheral blood lymphocytes. Combined treatment with vorinostat and 5'-DFUR resulted in a synergistic antiproliferative effect and increased apoptotic cell death in vitro. This latter effect was impaired in cells where TP was knocked. In vivo, vorinostat plus capecitabine potently inhibited tumour growth, increased apoptosis and prolonged survival compared with control or single-agent treatments. CONCLUSIONS: Overall, this study suggests that the combination of vorinostat and capecitabine is an innovative antitumour strategy and warrants further clinical evaluation for the treatment of CRC.

Dose intensity correlate with survival in elderly patients treated with chemotherapy for advanced non-small cell lung cancer.

INTRODUCTION: In elderly patients treated with chemotherapy for advanced non-small cell lung cancer (NSCLC), frequently an adequate dose intensity (DI) is difficult to be delivered. We therefore performed in this population a study to assess the delivered DI and its impact on clinical outcome. PATIENTS AND METHODS: Inclusion criteria were: age equal or greater than 70 years; cytological or histological diagnosis of NSCLC; stage IIIB or IV; no previous chemotherapy for advanced disease. Total relative dose intensity (RDI) was taken into account for the analysis. An RDI less than 80% was considered as suboptimal for tumor shrinkage. A survival comparison between subgroups (more or less than 80% RDI) was done. RESULTS: 107 patients were eligible for the analysis. Mean age was 74.3 years. PS was 0-1 in 92.5% of subjects. Mean number of comorbidities was 1.86. The most frequently chemotherapy regimens used were single agent vinorelbine and single agent gemcitabine. Overall mean RDI was 68%; 36% of patients received a RDI>80% of the originally planned one. The objective response rate (RR) was 55.2% and 33.3% respectively for patients receiving more or less than 80% of the RDI (p<0.01); a significant difference in overall survival between these two groups (p<0.0001) was also recorded. Baseline hemoglobin and body mass index (BMI) were the variables that significantly influenced the delivered RDI. CONCLUSIONS: These data suggest that in elderly patients treated with chemotherapy for advanced NSCLC an adequate dose intensity has a significant positive impact on both response rate and overall survival.

Pendellösung effect in photonic crystals.

At the exit surface of a photonic crystal, the intensity of the diffracted wave can be periodically modulated, showing a maximum in the "positive" (forward diffracted) or in the "negative" (diffracted) direction, depending on the slab thickness. This thickness dependence is a direct result of the so-called Pendell osung phenomenon, consisting of the periodic exchange inside the crystal of the energy between direct and diffracted beams. We report the experimental observation of this effect in the microwave region at about 14GHz by irradiating 2D photonic crystal slabs of different thickness and detecting the intensity distribution of the electromagnetic field at the exit surface and inside the crystal itself.

An open-label trial of levetiracetam in severe myoclonic epilepsy of infancy.

OBJECTIVE: To conduct an open-label, add-on trial on safety and efficacy of levetiracetam in severe myoclonic epilepsy of infancy (SMEI). PATIENTS AND METHODS: SMEI patients were recruited from different centers according to the following criteria: age > or =3 years; at least four tonic-clonic seizures/month during the last 8 weeks; previous use of at least two drugs. Levetiracetam was orally administrated at starting dose of approximately 10 mg/kg/day up to 50 to 60 mg/kg/day in two doses. Treatment period included a 5- to 6-week up-titration phase and a 12-week evaluation phase. Efficacy variables were responder rate by seizure type and reduction of the mean number per week of each seizure type. Analysis was performed using Fisher exact and Wilcoxon tests. RESULTS: Twenty-eight patients (mean age: 9.4 +/- 5.6 years) entered the study. Sixteen (57.1%) showed SCN1A mutations. Mean number of concomitant drugs was 2.5. Mean levetiracetam dose achieved was 2,016 mg/day. Twenty-three (82.1%) completed the trial. Responders were 64.2% for tonic-clonic, 60% for myoclonic, 60% for focal, and 44.4% for absence seizures. Number per week of tonic-clonic (median: 3 vs 1; p = 0.0001), myoclonic (median: 21 vs 3; p = 0.002), and focal seizures (median: 7.5 vs 3; p = 0.031) was significantly decreased compared to baseline. Levetiracetam effect was not related to age at onset and duration of epilepsy, genetic status, and concomitant therapy. Levetiracetam was well tolerated by subjects who completed the study. To date, follow-up ranges 6 to 36 months (mean, 16.2 +/- 13.4). CONCLUSION: Levetiracetam add-on is effective and well tolerated in severe myoclonic epilepsy of infancy. Placebo-controlled studies should confirm these findings.

Cryptic chromosome deletions involving SCN1A in severe myoclonic epilepsy of infancy.

OBJECTIVE: To identify cryptic chromosomal deletions involving SCN1A in patients with severe myoclonic epilepsy of infancy (SMEI). METHODS: Thirty-nine patients with SMEI and without SCN1A point mutations and their parents were typed with 14 intragenic SCN1A polymorphisms to identify hemizygosity. The parental origin and the extent of genomic deletions were determined by fluorescence in situ hybridization analysis using genomic clones encompassing chromosome 2q24.3-q31.1. Deletion breakpoints were more finely mapped by typing single-nucleotide polymorphisms and microsatellite markers. RESULTS: We identified three patients with SMEI who had genomic deletions encompassing the SCN1A locus. Deletion size was between 607 kb and 4.7 Mb. Deletions originated de novo from paternal chromosome in all subjects. One patient had central precocious puberty and palatoschisis. Genotype-phenotype correlations suggest that these clinical features are due to genes centromeric to SCN1A. CONCLUSIONS: Patients with severe myoclonic epilepsy of infancy (SMEI) lacking SCN1A point mutations should be investigated for cryptic chromosomal deletions involving SCN1A. Clinical features other than epilepsy could be associated with SMEI as a consequence of deletions in contiguous genes.

Experimental evidence of s-wave superconductivity in bulk CaC6.

The temperature dependence of the in-plane magnetic penetration depth, lambda(ab)(T), has been measured in a c-axis oriented polycrystalline CaC(6) bulk sample using a high-resolution mutual inductance technique. A clear exponential behavior of lambda(ab)(T) has been observed at low temperatures, strongly suggesting isotropic s-wave pairing. Data fit using the standard BCS theory yields lambda(ab)(0) = (720 +/- 80) A and delta(0) = (1.79 +/- 0.08) meV. The ratio 2delta(0)/k(B)T(c) = (3.6 +/- 0.2) gives indication for a weakly coupled superconductor.

Docetaxel induces p53-dependent apoptosis and synergizes with farnesyl transferase inhibitor r115777 in human epithelial cancer cells.

Docetaxel (Taxotere, DTX) is a promoter of apoptosis in cancer cells. Since cytotoxic mechanisms of DTX are not yet fully understood, we have investigated the effects of DTX on apoptosis and ras-->Erk-mediated signal transduction in human epidermoid KB, colon HT-29 and breast HCC1937 cancer cells. We have found that the exposure to 0.78 or 1.56 or 2.5 ng/ml DTX for 48 h induced apoptosis and growth inhibition in about 50 % of KB, HCC1937 and HT-29 cell population, respectively. In these experimental conditions, PARP and caspase 3 cleavage was also showed in all cell lines. KB and HCC1937 cells express a wild type p53 while HT-29 display a mutated form. Interestingly, we have found that DTX reduces the expression of mutated p53 in HT-29 and increases the expression of wild type in KB and HCC1937 cells. Moreover, DTX reduces ubiquitination of the wild type p53 in KB and HCC1937 cells and increases the ubiquitin-conjugated form of mutated p53 in HT-29 cells. Furthermore, exposure of cancer cells to DTX for 48 h increases the expression and activity of Ras and up-regulates Raf-1 and the phosphorylated isoforms of Erk-1/2. On the bases of these data, we have hypothesized that the increased activity of the ras-->erk-dependent pathway induced by DTX could be a protective signalling from the apoptosis caused by the drug. Therefore, we have used R115777, a farnesyl transferase inhibitor that inactivates ras, in combination with DTX. The combined treatment with DTX and R115777 resulted in a strong synergism in growth inhibition in the three cell lines. These data suggest the use of the combination in these therapeutic settings even if further experiments are required for the clinical translation.

Multiple-target drugs: inhibitors of heat shock protein 90 and of histone deacetylase.

In spite of the improvement of conventional medical therapy for cancer treatment, the impact on cancer related mortality in the last ten years has been modest especially for advanced disease in adults. On the other hand, understanding of molecular events underlining tumor development lead to the definition of new molecular targets for novel anti-tumor therapeutical approaches. On this regard, several biotechnology products selected by academic as well as industrial research are currently in clinical trials. Epigenetics as well as post-translational modifications of proteins are emerging as novel attractive targets for anticancer therapy. In addition, the heterogeneity of tumor cells within a selected neoplastic lesions as well as the redundancy of proliferative and survival pathways present in cancer cells favor the development of single drugs that are able to affect multiple pathways. Inhibitors of heat shock protein 90 and of histone deacetylase are two novel classes of multi-target agents that entered recently in clinical studies. This review will focus on the most important issues in the development of both these classes of agents.

Acetylation of proteins as novel target for antitumor therapy: review article.

Imbalance in histone acetylation can lead to changes in chromatin structure and transcriptional dysregulation of genes that are involved in the control of proliferation, cell-cycle progression, differentiation and/or apoptosis. Histone acetyltransferases (HATs) and histone deacetylases (HDACs), are two classes of enzymes regulating histone acetylation and whose altered activity has been identified in several cancers. HATs and HDACs enzymes also target non histone protein substrates, including transcription factors, nuclear import factors, cytoskeleton and chaperon proteins. HDAC inhibitors are a novel class of anticancer agents which have been recently shown to induce growth arrest and apoptosis in a variety of human cancer cells by mechanism that cannot be solely attributed to the level of histone acetylation. Several clinical studies with HDAC inhibitors are ongoing, however the molecular basis for their tumour selectivity remains unknown and represent a challenge for the cancer research community.

Absence of mutations in major GEFS+ genes in myoclonic astatic epilepsy.

Myoclonic astatic epilepsy (MAE) is a genetically determined condition of childhood onset characterized by multiple generalized types of seizures including myoclonic astatic seizures, generalized spike waves and cognitive deterioration. This condition has been reported in a few patients in generalized epilepsy with febrile seizures plus (GEFS+) families and MAE has been considered, like severe myoclonic epilepsy of infancy (SMEI), to be a severe phenotype within the GEFS+ spectrum. Four genes have been identified in GEFS+ families, but only three (SCN1A, SCNlB, GABRG2) were found in MAE patients within GEFS+ families. We analysed these three genes in a series of 22 sporadic patients with MAE and found no causal mutations. These findings suggest that MAE, unlike SMEI, is not genetically related to GEFS+. Although MAE and SMEI share the same types of seizures, only SMEI patients are sensitive to fever. This is probably its main link to GEFS+. A different family of genes is likely to account for MAE.

Spectrum of SCN1A mutations in severe myoclonic epilepsy of infancy.

OBJECTIVES: SCN1A mutations were recently reported in several patients with severe myoclonic epilepsy in infancy (SMEI). The authors analyzed SCN1A mutations in 93 patients with SMEI and made genotype-phenotype correlation to clarify the role of this gene in the etiology of SMEI. METHODS: All patients fulfilled the criteria for SMEI. The authors analyzed all patients for SCN1A mutations using denaturing high performance liquid chromatography. If a patient's chromatogram was abnormal, the authors sequenced the gene in the patient and both parents. RESULTS: SCN1A mutations were identified in 33 patients (35%). Most mutations were de novo, but were inherited in three patients. Parents carrying the inherited mutations had either no symptoms or a milder form of epilepsy. A greater frequency of unilateral motor seizures was the only clinical difference between patients with SCN1A mutations and those without. Truncating mutations were more frequently associated with such seizures than were missense mutations. The percentage of cases with family history of epilepsy was significantly higher in patients with SCN1A mutations. CONCLUSIONS: Unilateral motor seizures may be a specific clinical characteristic of SMEI caused by SCN1A mutations. Ten percent of SCN1A mutations are inherited from an asymptomatic or mildly affected parent, suggesting that SMEI is genetically heterogeneous. The increased frequency of familial epilepsy indicates that other genetic factors may contribute to this disorder.

EGF activates an inducible survival response via the RAS-> Erk-1/2 pathway to counteract interferon-alpha-mediated apoptosis in epidermoid cancer cells.

The mechanisms of tumor cell resistance to interferon-alpha (IFNalpha) are at present mostly unsolved. We have previously demonstrated that IFNalpha induces apoptosis on epidermoid cancer cells and EGF antagonizes this effect. We have also found that IFNalpha-induced apoptosis depends upon activation of the NH(2)-terminal Jun kinase-1 (Jnk-1) and p(38) mitogen-activated protein kinase, and that these effects are also antagonized by EGF. At the same time, IFNalpha increases the expression and function of the epidermal growth factor receptor (EGF-R). Here we report that the apoptosis induced by IFNalpha occurs together with activation of caspases 3, 6 and 8 and that EGF also antagonizes this effect. On the basis of these results, we have hypothesized that the increased EGF-R expression and function could represent an inducible survival response that might protect tumor cells from apoptosis caused by IFNalpha via extracellular signal regulated kinase 1 and 2 (Erk-1/2) cascades. We have found an increased activity of Ras and Raf-1 in IFNalpha-treated cells. Moreover, IFNalpha induces a 50% increase of the phosphorylated isoforms and enzymatic activity of Erk-1/2. We have also demonstrated that the inhibition of Ras activity induced by the transfection of the dominant negative Ras plasmid RASN17 and the inhibition of Mek-1 with PD098059 strongly potentiates the apoptosis induced by IFNalpha. Moreover, the selective inhibition of this pathway abrogates the counteracting effect of EGF on the IFNalpha-induced apoptosis. All these findings suggest that epidermoid tumor cells counteract the IFNalpha-induced apoptosis through a survival pathway that involves the hyperactivation of the EGF-dependent Ras->Erk signalling. The selective targeting of this pathway appears to be a promising approach in order to enhance the antitumor activity of IFNalpha.