A pleiotropy scan to discover new susceptibility loci for pancreatic ductal adenocarcinoma.

Pleiotropic variants (i.e., genetic polymorphisms influencing more than one phenotype) are often associated with cancer risk. A scan of pleiotropic variants was successfully conducted ten years ago in relation to pancreatic ductal adenocarcinoma susceptibility. However, in the last decade, genetic association studies performed on several human traits have greatly increased the number of known pleiotropic variants. Based on the hypothesis that variants already associated with a least one trait have a higher probability of association with other traits, 61,052 variants reported to be associated by at least one genome wide association study (GWAS) with at least one human trait were tested in the present study consisting of two phases (discovery and validation), comprising a total of 16,055 pancreatic ductal adenocarcinoma (PDAC) cases and 212,149 controls. The meta-analysis of the two phases showed two loci (10q21.1-rs4948550 (P=6.52×10-5) and 7q36.3-rs288762 (P=3.03×10-5) potentially associated with PDAC risk. 10q21.1-rs4948550 shows a high degree of pleiotropy and it is also associated with colorectal cancer risk while 7q36.3-rs288762 is situated 28,558 base pairs upstream of the Sonic Hedgehog (SHH) gene, which is involved in the cell differentiation process and PDAC etiopathogenesis. In conclusion, none of the single nucleotide polymorphisms (SNPs) showed a formally statistically significant association after correction for multiple testing. However, given their pleiotropic nature and association with various human traits including colorectal cancer, the two SNPs showing the best associations with PDAC risk merit further investigation through fine mapping and ad hoc functional studies.

Germline BRCA2 K3326X and CHEK2 I157T mutations increase risk for sporadic pancreatic ductal adenocarcinoma.

Rare truncating BRCA2 K3326X (rs11571833) and pathogenic CHEK2 I157T (rs17879961) variants have previously been implicated in familial pancreatic ductal adenocarcinoma (PDAC), but not in sporadic cases. The effect of both mutations in important DNA repair genes on sporadic PDAC risk may shed light on the genetic architecture of this disease. Both mutations were genotyped in germline DNA from 2,935 sporadic PDAC cases and 5,626 control subjects within the PANcreatic Disease ReseArch (PANDoRA) consortium. Risk estimates were evaluated using multivariate unconditional logistic regression with adjustment for possible confounders such as sex, age and country of origin. Statistical analyses were two-sided with p values <0.05 considered significant. K3326X and I157T were associated with increased risk of developing sporadic PDAC (odds ratio (ORdom ) = 1.78, 95% confidence interval (CI) = 1.26-2.52, p = 1.19 × 10-3 and ORdom = 1.74, 95% CI = 1.15-2.63, p = 8.57 × 10-3 , respectively). Neither mutation was significantly associated with risk of developing early-onset PDAC. This retrospective study demonstrates novel risk estimates of K3326X and I157T in sporadic PDAC which suggest that upon validation and in combination with other established genetic and non-genetic risk factors, these mutations may be used to improve pancreatic cancer risk assessment in European populations. Identification of carriers of these risk alleles as high-risk groups may also facilitate screening or prevention strategies for such individuals, regardless of family history.

Interleukin 15 concentrations in follicular fluid and their effect on oocyte maturation in subfertile women undergoing intracytoplasmic sperm injection.

PURPOSE: To calculate the concentrations of interleukin 15 (IL-15) in follicular fluid (FF) and evaluate their relation with oocyte maturation, follicle size, and patients' body mass index (BMI) and age. METHODS: Follicular fluid specimens were obtained from 56 subfertile women undergoing intracytoplasmic sperm injection (ICSI) during oocyte retrieval for measurement of IL-15 concentrations with ELISA. Wilcoxon's test and Pearson's correlation coefficient were used to correlate FF concentrations of IL-15 with follicular size and stage of oocyte maturation, along with patients' BMI and age. RESULTS: IL-15 concentrations in FF of follicles with immature oocytes were significantly greater than those from follicles with mature ones (median 5.333 vs. 3.250 pg/ml, respectively, p < 0.001). There was a significant negative correlation between IL-15 concentrations and follicle size (r = - 0.333, p = 0.003). No significant correlation was observed between IL-15 concentrations and patients' BMI and age (p > 0.05). CONCLUSIONS: IL-15 concentrations in FF are adversely related with the size of the follicles and the maturity of the corresponding retrieved oocytes in a cohort of expected normal responders undergoing intracytoplasmic sperm injection (ICSI). Follicular fluid concentrations of IL-15 should be investigated as a possible predictive factor for oocyte maturity.

Pharmacogenomics: current applications and future prospects towards personalized therapeutics.

Personalized Medicine is more than just a metabolic activity of a person. Pharmacogenomics, pharmacogenetics, pharmacoproteomics, and metabolomics play an important role in the development of personalized medicines. Personalized medicine uses information about a person's genes, proteins, enzyme activities, and cellular environment to diagnose and treat disease, cancer included. A major problem of personalized medicine is the fact that there is no portable bedside and low-cost bioanalytical technology that can be used in close proximity to the patient. This technology could play a significant role in defining the dosage setting for subsets of the population. The success of the personalized therapy is possible through the application of technology, which can provide a bridge between metabolism status and an individual's response to a particular drug and therapeutic modality.

Serotonin transporter and G protein beta 3 subunit gene polymorphisms in Greeks with irritable bowel syndrome.

BACKGROUND: Polymorphisms in the serotonin transporter (SERT) and G protein ß3 subunit (GNB3) genes might contribute to the pathophysiology of irritable bowel syndrome (IBS). Association studies of SERT and GNB3 polymorphisms and IBS have shown diverse results among different populations, which might be due to subject composition differences. AIMS: The aim of the study was to assess the potential association between SERT and GNB3 polymorphisms and IBS in Greeks. METHODS: A total of 124 patients with IBS diagnosed according to the Rome III criteria and 238 healthy individuals were included in the study. SERT and GNB3 gene polymorphisms were genotyped using polymerase chain reaction-based methods. RESULTS: It was shown that the frequencies of the SS genotype and S allele of the serotonin transporter polymorphism were significantly associated with IBS (P = 0.0314 and P = 0.019, respectively). TT genotype and T allele frequencies of G protein ß3 subunit showed also significant difference between the IBS patients and healthy controls IBS (P = 0.0163 and P = 0.0001, respectively). None of the clinical symptoms analyzed was significantly associated with the polymorphisms tested. CONCLUSIONS: The results suggest that SERT and GNB3 gene polymorphisms might be associated with irritable bowel syndrome predisposition in Greeks.

Efficacy of switching from infliximab to golimumab in patients with ulcerative colitis in deep remission.

BACKGROUND-AIM: Intravenously administered biologicals are associated with a huge pressure to Infusion Units and increased cost. We aimed to assess the impact of switching infliximab to golimumab in ulcerative colitis (UC) patients in deep remission. Patients and method: In a prospective, single-centre pilot study UC patients on infliximab mono-therapy for = 2 years, whowere in deep remission, consented to switch to golimumab and were followed for 1 year with clinical assessment, serum and faecal biomarkers, work productivity, satisfaction with treatment and quality of life parameters. Endoscopic remission was assessed by colonoscopy at 1 year. Patients fulfilling the same inclusion criteria, who did not consent to switch to golimumab and continued to receive infliximab mono-therapy, for the same period, served as controls. PATIENTS AND METHODS: In a prospective, single-centre pilot study UC patients on infliximab mono-therapy for ≥ 2 years, who were in deep remission, consented to switch to golimumab and were followed for 1 year with clinical assessment, serum and faecal biomarkers, work productivity, satisfaction with treatment and quality of life parameters. Endoscopic remission was assessed by colonoscopy at 1 year. Patients fulfilling the same inclusion criteria, who did not consent to switch to golimumab and continued to receive infliximab mono-therapy, for the same period, served as controls. RESULTS: Between October 2015 and October 2017, 20 patients were recruited; however one patient stopped therapy because of pregnancy. All 19 patients who were switched to golimumab were still in clinical, biomarker and endoscopic remission at 1 year and maintained excellent quality of life without any complications. In the control group, 18 of 19 patients were also in deep remission, since only one patient had a flare which was managed with IFX dose intensification. During a median 3 years extension treatment with golimumab only 2 patients experienced a flare of colitis. CONCLUSIONS: This pilot study indicates that switching from in-fliximab to golimumab in UC patients in deep remission does not compromise treatment effectiveness or the course of disease; golimumab offers a valid alternative to intravenous infliximab infusions during the COVID-19 pandemic.

Specific detection of unamplified mycobacterial DNA by use of fluorescent semiconductor quantum dots and magnetic beads.

Here we present the development of a specific DNA detection method using fluorescent semiconductor quantum dots (QDs) and magnetic beads (MBs) for fast detection of Mycobacterium spp., dispensing with the need for DNA amplification. Two biotinylated oligonucleotide probes were used to recognize and detect specific complementary mycobacterial target DNA through a sandwich hybridization reaction. Cadmium selenite QDs conjugated with streptavidin and species-specific probes were used to produce a fluorescent signal. MBs conjugated with streptavidin and a genus-specific probe were used to isolate and concentrate the DNA targets. The application of the proposed method to isolated bacteria produced the expected result in all cases. The minimum detection limit of the assay was defined as 12.5 ng of DNA diluted in a sample volume of 20 microl. In order to obtain an indication of the method's performance with clinical samples, we applied the optimized assay to the detection of Mycobacterium tuberculosis in DNA isolated from bronchoalveolar lavage specimens from patients with tuberculosis and Mycobacterium avium subsp. paratuberculosis in DNA isolated from feces and paraffin-embedded tissues in comparison with culture, Ziehl-Neelsen staining, and real-time PCR. The concordance of these methods compared to the proposed method with regard to positive and negative samples varied between 53.84% and 87.23% and between 84.61% and 100%, respectively. The overall accuracy of the QD assay compared to real-time PCR was 70 to 90% depending on the type of clinical material. The proposed diagnostic assay offers a simple, rapid, specific, and cost-effective method for direct detection and identification of mycobacterial DNA in clinical samples.

Thiopurine S-methyltransferase genotype and the use of thiopurines in paediatric inflammatory bowel disease Greek patients.

BACKGROUND AND OBJECTIVE: Azathioprine (AZA) and 6-mercaptopurine (6MP) are used in the treatment of paediatric inflammatory bowel disease (IBD). Genetic variations in thiopurine S-methyltranfarase (TPMT) gene have been correlated with enzyme activity and with the occurrence of adverse events to AZA and 6MP. The aim of the present study was to investigate the frequency of the functional TPMT polymorphisms and their association with the occurrence of adverse events during azathioprine therapy in a paediatric IBD cohort. METHODS: Ninety-seven thiopurine-treated paediatric IBD patients (41.24% boys and 58.76% girls) with a mean age 11.25 years (range 3-16), were assessed for TPMT polymorphisms and adverse events. RESULTS: Of the 97 patients enrolled in the study, 18 (18.56%) were heterozygous mutated; two (2.06%) were homozygous for a mutated TPMT gene. Ten patients (10.31%) developed adverse effects, and four of them (40%) had one of the variant alleles. CONCLUSIONS: In this small cohort of subjects, no association was found between TPMT polymorphisms and the occurrence of thiopurines-related adverse events.

Estimation of the spread of pathogenic mycobacteria in organic broiler farms by the polymerase chain reaction.

Organic poultry breeding allows for increased exposure of birds to soil, faeces, and wildlife, which have been associated with the transmission of mycobacterial infections. Therefore the aim of this study was to investigate the spread of the major pathogenic mycobacteria in organically reared broilers in Greece using a diagnostic algorithm that relied on a combination of the polymerase chain reaction (PCR) and the restriction fragment length polymorphism analysis (RFLP). Liver, spleen and gonads from 81 to 150 days old broilers were aseptically collected post-mortem. 500 broilers from a population of 35,370, reared in the 25 registered as organic farms in Greece for the 2005 were used. DNA was isolated and incorporated to PCR targeted to 16S-rRNA gene (for Mycobacterium spp.), IS6110 (for Mycobacterium tuberculosis complex-MTBc), IS1245 (for Mycobacterium avium complex-MAC), IS901 (for M. avium subsp. avium-MAA) and hsp65 (for Mycobacterium genavense, by PCR-RFLP). The mean prevalence of mycobacteria detected by PCR with a 95% confidence interval was estimated to 4.4-8.8%. The relevant percentage with regard to the mycobacterial species that were included in this study was 0.17-2.03% for MAC, 2.11-3.39% for MTBc and 0.66-3.08% for mycobacteria not belonging to any of the above groups. None of the mycobacteria detected were identified as MAA or M. genavense. Considering that avian tuberculosis has been eradicated from conventional farms, the level and the pattern of positivity recorded here, indicates that our results may be associated with the specific conditions that apply to organic breeding.

Does Helicobacter pylori identification in the mucosa of the gallbladder correlate with cholesterol gallstone formation?

OBJECTIVE: Helicobacter pylori (H pylori) represents a potential initiator of cholesterol crystallization and it has been proposed that it is related to gallstone formation. In this study, any possible association between the H pylori identification in the mucosa of gallbladder and cholesterol gallstone formation was evaluated METHODS: Gallbladders containing pure or mixed cholesterol gallstones (cholelithiasis group, n = 89) and gallbladders without gallstones (control group, n = 42) were submitted to standard histopathological examination for H pylori detection, as well as to nested polymerase chain reaction amplification for H pylori DNA detection. RESULTS: Helicobacter pylori was identified in the gallbladder's epithelium in four patients with cholelithiasis and in two patients in the control group by histology. In all the cases which were found to be H pylori positive by histological examination, H pylori DNA were also detected. No correlation between gallstone formation and H pylori detection in the biliary epithelium was found. A higher incidence of acute inflammation in the cholelithiasis (22.5% vs 9.5%, p = not significant [ns]) and in the H pylori positive groups (33% vs 17.6%, p = ns) were histologically detected. A higher incidence (10% vs 0%), p = ns) of H pylori in gallbladders with gallstones and acute inflammation, compared to gallbladders with acute inflammation but without gallstones, was noticed CONCLUSION: Helicobacter pylori is detectable in low frequency in the mucosa of the gallbladder and it does not seem to act as a lithogenic component for cholesterol gallstone formation. Its higher incidence in gallbladders with gallstones and acute inflammation, suggests a possible accessory role in a subset of patients with cholelithiasis.

Novel potential biomarkers for the diagnosis and monitoring of patients with ulcerative colitis.

Unambiguously, great progress has been achieved in the unraveling of more pathological pathways implicated in the development and progression of ulcerative colitis during the last decades. Novel effective drugs that have augmented the management armamentarium have been developed alongside this growing comprehension of the disease, rendering mucosal healing not only a feasible but the optimal goal of every therapy. Clinical evaluation, colonoscopy and biomarkers are the tools used by practitioners for the diagnosis and assessment of the status of the disease in order to achieve clinical remission and mucosal healing for their patients. Among these tools, colonoscopy is the gold method for the cause but is still an invasive, high-cost procedure with possible adverse events such as perforation. While clinical evaluation entails much subjectivity, biomarkers are objective, easily reproducible, non-invasive, cheap and potent surrogate tools of mucosal inflammation. Unfortunately, the well-established, currently in use serum biomarkers, such as C-reactive protein, erythrocyte sedimentation rate and others, do not display sufficiently acceptable sensitivity and specificity rates for the diagnosis of ulcerative colitis and, most importantly, do not represent precisely the mucosal inflammation status of the disease. Therefore, the discovery of new serum biomarkers has been the cause of several studies attempting to discover an "optimal" serum biomarker during the recent years. After thorough research, collection and examination of current data, this review focuses on and selectively presents promising, potential, novel serum biomarkers of ulcerative colitis as they are indicated by studies on the patient over the last years.

Association between genetic polymorphisms in long non-coding RNAs and pancreatic cancer risk.

BACKGROUND: Long non-coding RNAs (lncRNAs) are emerging as candidate biomarkers of cancer, having regulatory functions in both oncogenic and tumor-suppressive pathways. Concerning pancreatic cancer (PC), deregulation of lncRNAs involved in tumor initiation, invasion, and metastasis seem to play a key role. However, data is scarce about regulatory mechanism of lncRNA expression. OBJECTIVE: The aim of our study was to investigate the contribution of two lncRNAs polymorphisms (rs1561927 and rs4759313 of PVT1 and HOTAIR, respectively) in PC susceptibility. METHODS: A case-control study was conducted analysing rs1561927 and rs4759313 polymorphisms using DNA collected in a population-based case-control study of pancreatic cancer (111 pancreatic ductal adenocarcinoma cases (PDAC), 56 pancreatic neuroendocrine tumor (PNET), and 125 healthy controls). RESULTS: Regarding the PVT1 rs1561927 polymorphism the G allele was significantly overrepresented in both PDAC and PNET patients compared to the controls, while the presence of the HOTAIR rs4759314 G allele was found to be overrepresented in the PNET patients only compared to the controls. The PVT1 rs1561927 AG/GG genotypes were associated with poor overall survival in PDAC patients. CONCLUSIONS: Our results suggested that polymorphisms of these two lncRNA polymorphisms implicated in pancreatic carcinogenesis. Further large-scale and functional studies are needed to confirm our results.

Functional dyspepsia susceptibility is related to CD14, GNB3, MIF, and TRPV1 gene polymorphisms in the Greek population.

BACKGROUND: Functional dyspepsia (FD) susceptibility might be influenced by polymorphisms of genes related to inflammation (CD14, macrophage migration inhibitory factor [MIF]), motor (GNB3), and sensory dysfunction (GNB3, TRPV1). We examined the association between CD14 rs2569190, GNB3 rs5443, MIF rs222747, and TRPV1 rs755622 gene polymorphisms with FD (Rome III criteria) in the Greek population. METHODS: We genotyped 174 dyspeptics (115 with epigastric pain syndrome; 41% Helicobacter pylori positive) and 181 controls using polymerase chain reaction-based methods and we measured disease symptoms' burden with a modified Gastrointestinal Symptoms Related Scale. KEY RESULTS: Homozygous for the TT genotype and the T allele of the CD14 gene were significantly associated (OR [95% CI]) with FD (2.65 [1.42-4.94] and 1.67 [1.23-2.26], respectively). The CT, TT genotypes, and T allele frequencies of GNB3 showed also significant association with FD (2.18 [1.35-3.54], 3.46 [1.30-9.23], and 2.18 [1.48-3.19]). While heterozygous GC MIF genotype was more common in dyspeptics (1.67 [1.07-2.60]), homozygous CC genotype and the C allele of TRPV1 gene were more prevalent in controls (0.47 [0.25-0.87] and 0.69 [0.51-0.92], respectively). None of the gene polymorphism was related either to dyspepsia clinical syndrome type or to the H. pylori infection. Among dyspeptics, CD14 TT genotype was related to lower epigastric pain burden score (p<.011); CD14 CT genotype was related to higher epigastric burning and nausea burden scores (p<.04) while belching score was lower (p=.027) in MIF CG dyspeptics. CONCLUSION & INFERENCES: Functional dyspepsia susceptibility is related to CD14, GNB3, MIF, and TRPV1 gene polymorphisms, while CD14 and MIF gene variants are also associated with dyspepsia symptoms burden.

Determination of prevalence and risk factors of infection with Babesia in small ruminants from Greece by polymerase chain reaction amplification.

A total of 124 blood samples were collected from 92 sheep and 32 goats from 21 randomly selected herds located in two regions of Greece. Data on the characteristics of the animals (species, gender, age, tick burden, presence of haemoglobinuria, prior treatment for babesiosis) and the herd (location, size, species of animals, dogs associated with the herds, tick burden of dogs associated with the herds) were collected through questionnaires. Nineteen animals (15%) produced the DNA fragment specific for Babesia of which 16 were sheep and three were goats. Nucleotide sequence of PCR products revealed 100% homology with Babesia ovis 18S rRNA gene. Nine farms (43%) were found positive for B. ovis. The percentage of positive animals in each farm varied between 10 and 61%. The relative risk of the presence of ticks in sheep and goats (p<0.01) and farm dogs (p<0.01) for PCR-positive results for B. ovis in sheep and goats was found 6.63 and 4.14, respectively.

Therapeutic Potential of Secreted Molecules Derived from Human Amniotic Fluid Mesenchymal Stem/Stroma Cells in a Mice Model of Colitis.

Inflammatory bowel diseases (IBDs) are the result of pathological immune responses due to environmental factors or microbial antigens into a genetically predisposed individual. Mainly due to their trophic properties, a mounting interest is focused on the use of human mesenchymal stem/stromal cells (hMSCs) to treat IBD disease in animal models. The aim of the study is to test whether the secreted molecules, derived from a specific population of second trimester amniotic fluid mesenchymal stem/stromal cells, the spindle-shaped MSCs (SS-AF-MSCs), could be utilized as a novel therapeutic, cell free approach for IBD therapy. Induction of colitis was achieved by oral administration of dextran sulphate sodium (DSS) (3 % w/v in tap water), for 5 days, to 8-week-old NOD/SCID mice. The progression of colitis was assessed on a daily basis through recording the body weight, stool consistency and bleeding. Conditioned media (CM) derived from SS-AF-MSCs were collected, concentrated and then delivered intraperitoneally into DSS treated mice. To evaluate and determine the inflammatory cytokine levels, histopathological approach was applied. Administration of CM derived from SS-AF-MSCs cells reduced the severity of colitis in mice. More importantly, TGFb1 protein levels were increased in the mice received CM, while TNFa and MMP2 protein levels were decreased, respectively. Accordingly, IL-10 was significantly increased in mice received CM, whereas TNFa and IL-1b were decreased at mRNA level. Our results demonstrated that CM derived from SS-AF-MSCs cells is able to ameliorate DSS-induced colitis in immunodeficient colitis mouse model, and thus, it has a potential for use in IBD therapy.

Subtype C1 persistent infection of HHV-8 in a PEL patient.

PEL, a rare type of lymphoma constituting less than 5% of NHLs, has been recently identified as a distinct clinical and pathological entity among the B-cell lymphomas, with characteristic morphologic, immunophenotypic, molecular and viral features. ICC, PCR, RT-PCR and sequencing were carried out in biologicals samples from a 44-year-old, non-smoker Caucasian male patient of Greek nationality, HIV-1 negative and HCV positive. The ICC results showed CD30 + , Vimentin + , EMA + , Ki67 + , Pankeratin- and negative to B and T antibodies. In addition, HHV-8 was detected in pleural fluid. Examination of blood samples of the patient over a period of nearly two years showed a persistent infection of HHV-8. Phylogenetic analysis revealed a close relation to the C1 variant of HHV-8. The samples was also found EBV negative by PCR. Using a combination of clinical, morphological, immunohistochemical features and molecular biology techniques in this study we document a PEL case with persistent HHV-8 of genotype C1 infection.

Functional analysis of 3'UTR polymorphisms in the caprine SLC11A1 gene and its association with the Mycobacterium avium subsp. paratuberculosis infection.

The study aimed to investigate whether the genetic polymorphisms in the 3'UTR of the caprine SLC11A1 gene are functional, and to assess the role of MAP as a regulatory parameter in gene expression. To this goal we constructed plasmids expressing the Luciferase reporter gene in transient transfections of a mouse (Balb/c) macrophage cell line (RAW264.7), incorporating those polymorphisms that our previous work indicated as more prominent in terms of SLC11A1 expression and responsiveness to MAP infection. Gene expression variation was recorded on the average of the respective measurements after exposure to Mycobacterium avium subsp. paratuberculosis (MAP) combined with microbial antigens and cytokines. In silico analysis of the region under study allowed identification of one cis-acting RNA element, five putative transcriptional regulatory elements and 85 3'end microRNA binding sites. The two polymorphic regions (regions A and B) of the 3'UTR of the caprine SLC11A1 gene were recognized as regulators of its activity, at transcriptional and post-transcriptional level. The GT16 polymorphism at region A, combined with the GT8 polymorphism at region B, results in up-regulation of the SLC11A1 gene. The specific genotype was also found to be more responsive to MAP exposure at a statistically significant level.

Association of CD133 polymorphisms and response to bevacizumab in patients with metastatic colorectal cancer.

BACKGROUND: Bevacizumab, an angiogenesis inhibitor is used in regimens for metastatic colorectal cancer (CRC). A minority of cancer cells with characteristics of cancer stem cells (CSC) may be responsible for progression and development of chemotherapy resistance in this disease. CD133 is a well-known CSC marker and is associated with angiogenesis, poor prognosis and resistance to chemotherapy. OBJECTIVE: The purpose of our study was to evaluate the association between the rs3130 and rs2286455 polymorphisms of the CD133 gene and the response, toxicity, and overall survival of patients with CRC on bevacizumab-based treatment. METHODS: Forty-three patients receiving bevacizumab, irinotecan and capecitabine and 15 patients receiving bevacizumab, irinotecan and 5-FU were included. Efficacy and toxicity were evaluated. KRAS mutation analysis and rs3130 and rs2286455 polymorphisms genotyping in the tumors and peripheral blood respectively were performed with PCR-RFLP. RESULTS: No association between KRAS mutated alleles and response was found. The rs3130 CC genotype was associated with reduced toxicity of treatments (p= 0.0017), and with lower overall survival on bevacizumab (p= 0.002). CONCLUSIONS: The CC genotype of rs3130 polymorphism in the CD133 gene can predict poorer overall survival in patients with metastatic CRC on bevacizumab which cannot be attributed to increased treatment toxicity.

The peroxisome proliferator perfluorodecanoic acid inhibits the peripheral-type benzodiazepine receptor (PBR) expression and hormone-stimulated mitochondrial cholesterol transport and steroid formation in Leydig cells.

The peroxisome proliferator perfluordecanoic acid (PFDA) has been shown to exert an antiandrogenic effect in vivo by acting directly on the interstitial Leydig cells of the testis. The objective of this study was to examine the in vitro effects of PFDA and identify its site of action in steroidogenesis using as model systems the mouse tumor MA-10 and isolated rat Leydig cells. PFDA inhibited in a time- and dose-dependent manner the hCG-stimulated Leydig cell steroidogenesis. This effect was localized at the level of cholesterol transport into the mitochondria. PFDA did not affect either the total cell protein synthesis or the mitochondrial integrity. Moreover, it did not induce any DNA damage. Morphological studies indicated that PFDA induced lipid accumulation in the cells, probably due to the fact that cholesterol mobilized by hCG did not enter the mitochondria to be used for steroidogenesis. In search of the target of PFDA, we examined its effect on key regulatory mechanisms of steroidogenesis. PFDA did not affect the hCG-induced steroidogenic acute regulatory protein (StAR) levels. However, it was found to inhibit the mitochondrial peripheral-type benzodiazepine receptor (PBR) ligand binding capacity, 18-kDa protein, and messenger RNA (mRNA) levels. Further studies indicated that PFDA did not affect PBR transcription, but it rather accelerated PBR mRNA decay. Taken together, these data suggest that PFDA inhibits the Leydig cell steroidogenesis by affecting PBR mRNA stability, thus inhibiting PBR expression, cholesterol transport into the mitochondria, and the subsequent steroid formation. Moreover, this action of PFDA on PBR mRNA stability indicates a new mechanism of action of peroxisome proliferators distinct from the classic transcription-mediated regulation of target genes.

Effect of substitution of Asn for Arg-276 in the cefotaxime-hydrolyzing class A beta-lactamase CTX-M-4.

The effect of substitution of asparagine for arginine at position 276 (Ambler's numbering) on the properties of the extended-spectrum beta-lactamase CTX-M-4 was studied. Compared with CTX-M-4, the mutant beta-lactamase CTX-M-4(R276N) conferred lower levels of resistance to cefotaxime, ceftriaxone and aztreonam while the levels of resistance to penicillins and penicillin-inhibitor combinations were similar. Arg-276-->Asn substitution rendered CTX-M-4 slightly less susceptible to inhibition by clavulanate and tazobactam. It also caused a three-fold reduction in the relative rate of hydrolysis of cefotaxime. These results indicate that Arg-276 in CTX-M-type beta-lactamases may be implicated in hydrolysis of oxyimino-beta-lactams; they do not, however, support the hypothesis that Arg-276 is the functional equivalent of Arg-244 found in other class A beta-lactamases.