Cognitive control over memory - individual differences in memory performance for emotional and neutral material.

It is widely accepted that people differ in memory performance. The ability to control one's memory depends on multiple factors, including the emotional properties of the memorized material. While it was widely demonstrated that emotion can facilitate memory, it is unclear how emotion modifies our ability to suppress memory. One of the reasons for the lack of consensus among researchers is that individual differences in memory performance were largely neglected in previous studies. We used the directed forgetting paradigm in an fMRI study, in which subjects viewed neutral and emotional words, which they were instructed to remember or to forget. Subsequently, subjects' memory of these words was tested. Finally, they assessed the words on scales of valence, arousal, sadness and fear. We found that memory performance depended on instruction as reflected in the engagement of the lateral prefrontal cortex (lateral PFC), irrespective of emotional properties of words. While the lateral PFC engagement did not differ between neutral and emotional conditions, it correlated with behavioural performance when emotional - as opposed to neutral - words were presented. A deeper understanding of the underlying brain mechanisms is likely to require a study of individual differences in cognitive abilities to suppress memory.

Stable DHLA-PEG capped PbS quantum dots: from synthesis to near-infrared biomedical imaging.

The short shelf-life of water-soluble quantum dots (QDs) due to colloidal instability represents a major drawback to their exploitation. This work examines the colloidal stability of PbS nanoparticles capped with dihydrolipoic acid-polyethylene glycol (DHLA-PEG) ligands terminated with functional groups such as -NH2, -COOH, OMe and -N3. and their application for in vivo imaging. We prove a mechanism of colloidal instability and develop a strategy to produce for the first time stable PEG-capped PbS quantum dots with high quantum yield and optical emission in the first and the second near-infrared (NIR) windows of low absorption of biological tissues. The NIR imaging of in vivo biodistribution is demonstrated at wavelengths >1000 nm, with benefits of reduced tissue absorption and light scattering. The stability, biocompatibility and potential for further QD functionalization open up realistic prospects for non-invasive bioimaging applications.

In Vitro Tissue Microarrays for Quick and Efficient Spheroid Characterization.

Three-dimensional (3D) in vitro microphysiological cultures, such as spheroids and organoids, promise increased patient relevance and therapeutic predictivity compared with reductionist cell monolayers. However, high-throughput characterization techniques for 3D models are currently limited to simplistic live/dead assays. By sectioning and staining in vitro microtissues, researchers can examine their structure; detect DNA, RNA, and protein targets; and visualize them at the level of single cells. The morphological examination and immunochemistry staining for in vitro cultures has historically been done in a laborious manner involving testing one set of cultures at a time. We have developed a technology to rapidly screen spheroid phenotype and protein expression by arranging 66 spheroids in a gel array for paraffin embedding, sectioning, and immunohistochemsitry. The process is quick, mostly automatable, and uses 11 times less reagents than conventional techniques. Here we showcase the capabilities of the technique in an array made up of 11 different cell lines stained in conventional hematoxylin and eosin (H&E) staining, as well as immunohistochemistry staining for estrogen (ER), progesterone (PR), and human epidermal growth factor (Her-2) receptors, and TP53. This new methodology can be used in optimizing stem cell-based models of disease and development, for tissue engineering, safety screening, and efficacy screens in cancer research.

Data on the number and frequency of scientific literature citations for established medulloblastoma cell lines.

This article collates information about the number of scientific articles mentioning each of the established medulloblastoma cell lines, derived through a systematic search of Web of Science, Scopus and Google Scholar in 2016. The data for each cell line have been presented as raw number of citations, percentage share of the total citations for each search engine and as an average percentage between the three search engines. In order to correct for the time since each cell line has been in use, the raw citation data have also been divided by the number of years since the derivation of each cell line. This is a supporting article for a review of in vitro models of medulloblastoma published in "in vitro models of medulloblastoma: choosing the right tool for the job" (D.P. Ivanov, D.A. Walker, B. Coyle, A.M. Grabowska, 2016) [1].

Intellectual functioning of childhood leukemia survivors--relation to Tau protein--a marker of white matter injury.

PURPOSE: Chemo- and radiotherapy used in acute lymphoblastic leukemia (ALL) can influence on brain functioning in the future. In a prospective study we analysed the cognitive functions of ALL survivors in relation to Tau protein as a marker of white matter injury. MATERIAL AND METHODS: Thirty-one survivors of childhood ALL (6.3 years after diagnosis); without the signs of CNS involvement, treated with chemotherapy alone, rested in first remission; underwent Intelligence tests- Wechsler Intelligence Scales (WISC-R, WAIS-R). Their results were analyzed in relation to the levels of Tau in cerebrospinal fluid (CSF) obtained during the treatment. RESULTS: The analysis showed that all survivors attained the average scores in intelligence tests. A negative correlation was found between methotrexate (MTX) doses and Freedom from Distractibility (FFD). Females had higher values of Performance Intelligence Quotient (PIQ) than males. A negative correlation was noted of Tau protein levels obtained from the last CSF with: Total and Verbal Intelligence Quotient, PIQ, Perceptual Organisation Index and FFD but not with Verbal Comprehension Index. CONCLUSION: Our results suggest the possibility of white matter injury during the treatment for ALL with chemotherapy alone. Elevated Tau protein level in CSF at the end of treatment might indicate future difficulties in neurocognitive functioning.

A supersaturated calcium phosphate solution seems to effectively prevent and treat oral mucositis in haematopoietic stem cell transplanted cancer patients - single centre experience.

PURPOSE: Oral mucositis (OM) is one of the most frequent and bothersome complications of high-dose chemotherapy with subsequent auto- and allogeneic haematopoietic stem cell transplantation (HSCT). We have assessed the effectiveness of supersaturated calcium phosphate rinse (Caphosol ®) and palifermin (Kepivance®) in the prophylaxis of OM caused by HSCT. METHODS: Caphosol® and Kepivance® were prospectively evaluated in OM prophylaxis in 64 patients after HSCT and compared against themselves and an historical control group. RESULTS: Grade 3 and 4 OM was not observed in patients treated with Caphosol® and palifermin. None of those patients needed total parenteral nutrition (TPN), too. In the Caphosol® group 40.9% of the patients did not develop OM, and 70% of patients treated with palifermin were free of any kind of OM symptoms. In the control group OM was observed in all cases. CONCLUSION: Caphosol® seems to decrease the incidence, severity and duration of OM, the demand for opioids and for TPN. It needs to be tested in randomized trials, because its easy administration and cost-effectiveness may render it a valuable addition to the standard care in the treatment of OM.

Triple drug combination in the prevention of nausea and vomiting following busulfan plus cyclophosphamide chemotherapy before allogeneic hematopoietic stem cell transplantation.

PURPOSE: A clinical study of triple drug combination (aprepitant+palonosetron+ dexamethasone) was carried out to evaluate its efficacy in preventing both acute and delayed emesis after high-dose chemotherapy (HDC) with busulphan+cyclophosphamide (BuCy) before hematopoietic stem cell transplantation (HSCT). METHODS: The study enrolled 60 patients suffering from various hematological malignancies: 20 in the triple drug antiemetic group and 20 in each of two historical control groups that received dexamethasone plus either ondansetron or palonosetron. The groups were comparable for statistical analysis. The observation period started with the initiation of chemotherapy (0 h) and continued for 24 h after its completion for the acute phase, and during 5 days after finishing chemotherapy for the delayed phase. The response rate of the study drugs was evaluated by a 4-grade scale based on the condition of nausea and vomiting: highly, moderately or slightly effective and not effective. RESULTS: Patients treated with the triple drug combination had significantly higher response rates than those receiving palonosetron or ondansetron (+ dexamethasone) during both the acute and delayed phases: highly effective in early + late phases: 55 vs. 30 vs. 20%; highly effective in early phase: 70 vs. 30 vs. 20%; highly effective in late phase: 55 vs. 55 vs. 30%; highly + moderately effective in early phase: 75 vs. 32 vs. 25%; highly + moderately effective in late phase: 85 vs. 60 vs. 40% for triple drug combination, palonosetron + dexamethasone and ondansetron + dexamethasone, respectively. CONCLUSION: This triple drug combination was more effective than ondansetron or palonosetron (+ dexamethasone) in preventing acute (especially), and delayed nausea and vomiting following BuCy chemotherapy before HSCT.

A triple-drug combination to prevent nausea and vomiting following BEAM chemotherapy before autologous hematopoietic stem cell transplantation.

OBJECTIVE: We performed a clinical study of a triple-drug combination to evaluate its efficacy to prevent both acute and delayed emesis after high-dose chemotherapy with BEAM (BCNU [carmustine]+etoposide+ARA-C [cytarabine]+melphalan) before hematopoietic stem cell transplantation (HSCT) by comparison with a historical control group of patients treated with dexamethasone (dex) and ondansetron or palonosetron. METHODS: We evaluated 96 patients non-Hodgkin's lymphomas (n=54), and Hodgkin's disease (n=42). Evaluated patients received: aprepitant+palonosetron and dex. The observation period started with the initiation of chemotherapy (0 hours) and continued for 24 hours after the completion of the chemotherapy for the acute phase, and during 5 days after finishing chemotherapy for the delayed phase. The response rate to study drugs was evaluated using a four-grade scale based on the degree of control of nausea and vomiting: high, modrate, slightly effective, or not effective. RESULTS: Patients treated with the three-drug combination showed a significantly higher response rate than those receiving palonosetron or ondasetron (+dex) during the both the acute and the delayed phases: highly effective early+late phases, 82% versus 70% versus 35%; highly effective early phase, 94% versus 70% versus 35%; highly effective late phase, 85% versus 85% versus 50%; highly+moderately effective early phase, 97% versus 70% versus 40%; highly+moderately effective late phase, 97% versus 90% versus 60%, for triple combination, palonosctron with dexamethasone and ondasetron+dex, respectively. All antiemetic regimens were well tolerated. The three-drug combination showed a similar safety profile; adverse events were generally mild and transient. CONCLUSIONS: The triple-drug combination was more effective than ondansetron or palonosetron (+dex) treatments to prevent acute (especially) and delayed nausea and vomiting following BEAM before HSCT.

Efficiency of supersaturated calcium phosphate mouth rinse treatment in patients receiving high-dose melphalan or BEAM prior to autologous blood stem cell transplantation: a single-center experience.

OBJECTIVE: Oral mucositis (OM) is an unresolved problem among patients treated with a high-dose therapy supported by hematopoietic stem cell transplantation (HSCT). We tested the ability of supersaturated calcium phosphate mouth rinse (Caphosol) to ameliorate oral mucosal injury induced by a conditioning regimen. PATIENTS AND METHODS: Thirty-two patients with hematologic malignancies were treated with Caphosol to prevent OM during HSCT procedures. The conditioning regimens for 16 patients were BGNU 300 mg/m2, day 6; ARA-C 200 mg/m2 daily, days 5, 4, 3, 2; VP-16 200 mg/m2 daily, days 5, 4, 3, 2; L-PAM 140 mg/m2, day 1 (BEAM) and for 16 patients, MEL 200 (non-Hodgkin's lymphoma). A control group was composed of 24 consecutive patients, who had been treated with HSCT before Caphosol was available. The source of the graft was autologous peripheral blood. RESULTS: Among patients treated with Caphosol no one had to receive total parenteral nutrition. Among the BEAM group no one experienced III to IV degree OM compared with 40% of the control group. The median OM duration was 2.25 days versus controls of 8.6, (P<.001); only one patient received opioids versus 100% of controls. In the MEL 200 group, 93.7% of patients developed 0 to II degree OM vs 94% of the control group (P=.74) with median duration of 1, 73 days versus 2.42 for the controls (P=.73). In both control and Caphosol cohorts one patient received opioids. CONCLUSION: Caphosol may reduce the incidence, severity, and duration of oral mucositis and decrease the number of days with painkillers among patients treated with a BEAM but not a Mel 200 regimen.

Hematologic recovery in patients who are treated with autologous stem cells transplantation taken from bone marrow after granulocyte-colony-stimulating factor stimulation.

BACKGROUND: We sought to compare hematologic recovery between patients who did or did not receive granulocyte-colony-stimulating factor (G-CSF)-stimulated bone marrow (rich bone marrow [RBM]). MATERIALS AND METHODS: The study subjects were 20 patients whose bone marrow was taken without prior stimulation with G-CSF and 15 patients in whom bone marrow was taken after previous G-CSF mobilization. The bone marrow harvest took place on the fifth day after G-CSF initiation. The bone marrow aliquot was 20 mL/kg. RESULTS: The median value of nucleated cells obtained from patients without G-CSF preparation was 3.65×10(8)/kg. The median value of nucleated cells from RBM patients was 4.83×10(8)/kg. The median value of stem cells obtained from patients without G-CSF preparation was 0.96×10(6)/kg versus 1.9×10(6)/kg from RBM patients. The median time to recovery of the hematopoietic system based on an increase in PLT value>20 g/L was 12.6 days for RBM versus 18.8 days without G-CSF preparation. The median time to recovery of the hematopoietic system based on assessment of growth ANC>0.5 g/L was 13.0 days for RBM versus 17.8 days without G-CSF stimulation. Significantly higher values of nucleated cells and increased stem cells were observed among RBM patients compared with those whose bone marrow was harvested without any stimulation (P=.01). There was faster recovery of the hematopoietic system in cases where bone marrow was collected after G-CSF: PLT>20 g/L (P=.015) and ANC>0.5 g/L (P=.01). We also observed that the use of stimulated bone marrow shortened hospital stay after the administration of hematopoietic cells to 17.3 days compared with 23.1 days among patients receiving hematopoietic cells from nonstimulated bone marrow. The number of complications during transplantation was comparable in both cases, the most frequent ones being febrile neutropenia and grade III and IV mucositis. CONCLUSION: RBM is a better method to obtain stem cells from bone marrow. Stimulated bone marrow shows faster engraftment compared with nonstimulated bone marrow helping patients who fail to generate are adequate number of stem cells from peripheral blood.

Emotionally negative stimuli can overcome attentional deficits in patients with visuo-spatial hemineglect.

Left unilateral spatial neglect resulting from right brain damage is characterized by loss of awareness for stimuli in the contralesional side of space, despite intact visual pathways. We examined using fMRI whether patients with neglect are more likely to consciously detect in the neglected hemifield, emotionally negative complex scenes rather than visually similar neutral pictures and if so, what neural mechanisms mediate this effect. Photographs of emotional and neutral scenes taken from the IAPS were presented in a divided visual field paradigm. As expected, the detection rate for emotional stimuli presented in the neglected field was higher than for neutral ones. Successful detection of emotional scenes as opposed to neutral stimuli in the left visual field (LVF) produced activations in the parahippocampal and anterior cingulate areas in the right hemisphere. Detection of emotional stimuli presented in the intact right visual field (RVF) activated a distributed network of structures in the left hemisphere, including anterior and posterior cingulate cortex, insula, as well as visual striate and extrastriate areas. LVF-RVF contrasts for emotional stimuli revealed activations in right and left attention related prefrontal areas whereas RVF-LVF comparison showed activations in the posterior cingulate and extrastriate visual cortex in the left hemisphere. An additional analysis contrasting detected vs. undetected emotional LVF stimuli showed involvement of left anterior cingulate, right frontal and extrastriate areas. We hypothesize that beneficial role of emotion in overcoming neglect is achieved by activation of frontal and limbic lobe networks, which provide a privileged access of emotional stimuli to attention by top-down modulation of processing in the higher-order extrastriate visual areas. Our results point to the importance of top-down regulatory role of the frontal attentional systems, which might enhance visual activations and lead to greater salience of emotional stimuli for perceptual awareness.

Excited-state intramolecular proton transfer reaction modulated by low-frequency vibrations: an effect of an electron-donating substituent on the dually fluorescent bis-benzoxazole.

Excited-state intramolecular proton transfer (ESIPT) reaction has been studied in a molecule showing dual fluorescence, the 2,5-bis(2-benzoxazolyl)-4-methoxyphenol (BBMP), and its isotopomers, where the methoxy, and alternatively, the OH group has been deuterated. Attention is focused on the influence of electron donating OCH(3) substituent on fast excited state reaction. Comparison between the resonance-enhanced multiphoton ionization spectrum and the laser-induced excitation of the primary and phototautomeric emissions has been done. The geometry, electron density distribution, vibrational structure as well as the potential energy profiles in the S(0) and S(1) states of four possible rotameric forms of BBMP were calculated with application of the density functional theory (DFT). It allowed identifying the most probable conformer and assessing the role of low-frequency motions for the ESIPT efficiency.

Implicit phonological and semantic processing in children with developmental dyslexia: evidence from event-related potentials.

Dyslexia is characterized by a core phonological deficit, although recent studies indicate that semantic impairment also contributes to this condition. In this study, event-related potentials (ERP) were used to examine whether the N400 wave in dyslexic children is modulated by phonological or semantic priming, similarly to age-matched controls. ERPs were recorded while children listened to word lists in which the semantic and phonological congruency of the terminal words were manipulated. No overt judgments were made by participants. In control children the N400 amplitude to both semantically and phonologically incongruent words was enlarged relative to congruent words. Dyslexic children exhibited a dissociation of priming effects depending on whether semantic or phonological primes were used. Semantic priming elicited an N400 effect comparable to controls, though delayed. In phonological priming, the dyslexics differed from controls in both the phonologically incongruent and congruent conditions showing reduced N400 amplitude in the former and enhanced N400 in the latter. This pattern suggests that when faced with phonological priming, dyslexics show abnormal neural responses related to both integration of similarities between the consecutive stimuli and the ability to detect incongruent stimuli. Semantic priming seems relatively intact in dyslexics, however neural responses to contextual incongruency are delayed.

Cerebrospinal fluid changes in the excitatory amino acids concentration caused by the standard treatment of acute lymphoblastic leukaemia in children do not correlate with their later cognitive functioning.

The aim of this study was to ascertain whether changes in the concentrations of cerebrospinal fluid excitatory amino acids (EAAs) contribute to neurotoxicity of the standard acute lymphoblastic leukaemia (ALL) treatment protocols. We found a statistically significant increase in glutamate and aspartate in 12 ALL patients during their treatment. Cognitive functioning was examined in all patients at an average of 3.7 years after the disease diagnosis. Importantly, the levels of EAAs during the therapy were not correlated with the results of the cognitive test. This study suggests that standard ALL treatment-induced neurotoxicity may not lead to persistent neurocognitive deficits.

A gastrin transcript expressed in gastrointestinal cancer cells contains an internal ribosome entry site.

As the hormone gastrin promotes gastrointestinal (GI) cancer progression by triggering survival pathways, regulation of gastrin expression at the translational level was explored. Sequence within the 5' untranslated region of a gastrin transcript expressed in GI cancer cells was investigated, then cloned into a bicistronic vector upstream of firefly luciferase and transfected into a series of GI cancer cell lines. Firefly luciferase activity was measured relative to that of a cap-dependent Renilla luciferase. A gastrin transcript that was different from that described in Ensembl was expressed in GI cancer cells. Its transcription appears to be initiated within the region designated as the gene's first intron. In GI cancer cells transfected with the bicistronic construct, firefly luciferase activity increased 8-15-fold compared with the control vector, and there was a further induction of the signal (up to 25-fold) following exposure of the cells to genotoxic stress or hypoxia, suggesting that the sequence acts as an internal ribosome entry site. These data suggest that the gastrin transcript within GI cancer cells contains an internal ribosome entry site that may allow continued expression of gastrin peptides when normal translational mechanisms are inactive, such as in hypoxia, thereby promoting cancer cell survival.

False recognition of emotional stimuli is lateralised in the brain: An fMRI study.

We have investigated whether the left (LH) and right (RH) hemisphere play a different role in eliciting false recognition (FR) and whether their involvement in this memory illusion depends on the emotional content of stimuli. Negative and neutral pictures (taken from IAPS) were presented in the divided-visual field paradigm. Subjects task was to indicate whether the pictures had already been presented or not during the preceding study phase. FR rate was much higher for the RH than the LH presentations. In line, FR resulted in activations mainly in the right prefrontal cortex (PFC) for either RH or LH presentations. Emotional content of stimuli facilitated the formation of false memories and strengthened the involvement of the right PFC in FR induction.

Pre-clinical evaluation of a new orally-active CCK-2R antagonist, Z-360, in gastrointestinal cancer models.

BACKGROUND: Gastrin has a role in gastrointestinal (GI) malignancy. This study provides pre-clinical evaluation of a novel, orally-active gastrin/cholecystokinin-2 receptor (CCK-2R) antagonist, Z-360. METHODS: (125)I gastrin-17 (G17) displacement and G17-stimulated calcium assays were used in classical CCK-2R-transfected cell lines. Akt phosphorylation was assessed by Western blotting. Z-360 efficacy in vivo was evaluated in three human xenograft models, and microvessel density and apoptosis in these models were investigated by immunohistochemistry. RESULTS: Z-360 inhibited (125)I G17 binding to cells expressing CCK-2R, and G17-stimulated signalling. Reduced Akt phosphorylation in an oesophageal cell-line treated with Z-360 was reversed by co-treatment with G17. Z-360 increased survival in a gastric ascites model (p=0.011) and decreased tumour growth in a hepatic metastasis model (81%, p=0.02). In an orthotopic pancreatic model, Z-360 combined with gemcitabine decreased final tumour weight compared to single agents (84%, p=0.002) and there was increased apoptosis and decreased microvessel density in ex vivo tumour tissue. CONCLUSIONS: These results show that the orally-active CCK-2R antagonist, Z-360 has high sub-nM affinity for classical CCK-2R, is well tolerated in vivo and exerts an anti-tumour effect.

De-regulation of the sonic hedgehog pathway in the InsGas mouse model of gastric carcinogenesis.

This study investigated sonic hedgehog (Shh) signalling in gastric metaplasia in the insulin-gastrin (InsGas) hypergastrinaemic mouse +/- Helicobacter felis (H. felis) infection. Sonic hedgehog gene and protein expression was reduced in pre-metaplastic lesions from non-infected mice (90% gene reduction, P<0.01) compared to normal mucosa. Sonic hedgehog was reactivated in gastric metaplasia of H. felis-infected mice (3.5-fold increase, P<0.01) compared to pre-metaplastic lesions. Additionally, the Shh target gene, glioma-associated oncogene (Gli)-1, was significantly reduced in the gastric glands of InsGas mice (75% reduction, P<0.05) and reactivated with H. felis infection (P<0.05, base of glands, P<0.01 stroma of metaplastic glands). The ability of H. felis to activate the Shh pathway was investigated by measuring the effect of target cytokine, interleukin-8 (IL-8), on Shh expression in AGS and MGLVA1 cells, which was shown to induce Shh expression at physiological concentrations. H. felis induced the expression of NF-kappaB in inflammatory infiltrates in vivo, and the expression of the IL-8 mouse homologue, protein KC, in inflammatory infiltrates and metaplastic lesions. Sonic hedgehog pathway reactivation was paralleled with an increase in proliferation of metaplastic lesions (15.75 vs 4.39% in infected vs non-infected mice, respectively, P<0.001). Furthermore, Shh overexpression increased the growth rate of the gastric cancer cell line, AGS. The antiapoptotic protein, bcl-2, was expressed in the stroma of infected mice, along with a second Shh target gene, patched-1 (P=0.0001, stroma of metaplastic gland). This study provides evidence suggesting reactivation of Shh signalling from pre-metaplastic to advanced metaplastic lesions of the stomach and outlines the importance of the Shh pathway as a potential chemoprophylactic target for gastric carcinogenesis.

PTHrP increases transcriptional activity of the integrin subunit alpha5.

Increasing evidence is emerging highlighting the role of parathyroid hormone-related protein (PTHrP) during metastasis by regulating cell adhesion. The current study demonstrated that modulation of PTHrP expression by PTHrP overexpression and small interfering RNA-induced silencing resulted in changes in cell adhesion and integrin expression. RNA interference of endogenous PTHrP caused a significant reduction in cell adhesion of a breast cancer cell line to collagen type I, fibronectin and laminin (P<0.05) and of a colon cancer cell to collagen type I and fibronectin (P<0.05). Overexpression of PTHrP induced a significant increase in cell adhesion of colon (P<0.0001) and breast (P<0.05) cancer cells to the same extracellular matrix proteins. These PTHrP-mediated effects were attributed to changes in integrin expression as the differences in adhesion profile correlated with the integrin expression profile. In an attempt to elucidate the mechanism whereby PTHrP regulates integrin expression, promoter activity of the integrin alpha5 subunit was analysed and significant increases in transcriptional activity were observed in PTHrP overexpressing cells (P<0.0001), which was dependent on nuclear localisation. These results indicate that modulation of cell adhesion is a normal physiological action of PTHrP, mediated by increasing integrin gene transcription.

Use of interfering RNA to investigate the role of endogenous gastrin in the survival of gastrointestinal cancer cells.

Gastrin isoforms, acting through a variety of receptors, have proliferative and anti-apoptotic effects on gastrointestinal (GI) cancers. A small interfering RNA (siRNA) targeting the gastrin gene was used to investigate the role of endogenous gastrin in GI cancer cell survival. Downregulation of the gastrin gene in siRNA-transfected cells was measured using real-time reverse transcriptase-PCR. The most effective siRNA was tested in a panel of GI cancer cell lines at various concentrations and time points, and the effect on cell survival and apoptosis was measured using methyl thiazoyl tetrazolium (MTT) and caspase 3 activation assays. Gastrin siRNA reduced gene expression by more than 90% in a range of GI cancer cell lines. Downregulation of the gastrin gene was dose-dependent and effective over approximately 1 week in vitro. However, downregulation at the protein level was delayed by 3-4 days. Gastrin siRNA-transfected cells showed up to a 60% reduction in growth and up to a 50% increase in apoptosis compared with control siRNA-transfected cells. The effects were most marked in the cell line with the highest constitutive level of gastrin gene expression (human metastatic colon, C170HM2) and in epidermal growth factor (EGF)-treated cells as the gastrin promoter contains an EGF-response element, gERE. The ability of the siRNAs to reduce survival of these GI cell lines is further evidence of the importance of autocrine and/or intracrine gastrin loops in GI cancer, where expression of the gastrin gene and autonomous gastrin appears widespread.