Strategies for diagnosis and management of CMMRD in low-resource countries: report of a Tunisian family.

Constitutional Mismatch Repair Deficiency (CMMRD) is a rare childhood cancer predisposition syndrome, caused by biallelic pathogenic germline variants in the mismatch repair genes. Diagnosis and management of this syndrome is challenging, especially in low-resource settings. This study describes a patient diagnosed with colorectal cancer and grade 3 astrocytoma at the age of 11 and 12 respectively. Immunohistochemistry analysis showed a loss of MSH2 and MSH6 protein expression in CRC tissues of the patient. We identified by Targeted Exome Sequencing a homozygous pathogenic germline variant in exon 9 of the MSH6 gene (c.3991 C > T; p.Ala1268Glyfs*6). Genetic investigation of the family showed that the father was heterozygous for the identified pathogenic variant while the brother was wild type for this variant. Our study highlights the importance of a correct and timely diagnosis of CMMRD which can have implications for treatment. It also underlines the imperative need to enhance awareness, diagnostic standards, and surveillance that are crucial for patients and their families.

Polo-like kinase inhibitor BI2536 induces eryptosis.

BI2536 is potent inhibitor of polo-like kinases PLK1, 2, and 3. The inhibition of PLKs in nucleated cells induces apoptosis by perturbing the cell cycle with consequent engagement of mitotic catastrophe. BI2536 is being tested as chemotherapy in various phase I/II/III clinical trials. Erythrocytes do not have a nucleus; however, they may undergo programmed suicide with characteristic hallmarks including cell shrinkage and phosphatidylserine translocation to the cell surface. This particular death is baptized eryptosis. Our study explored whether BI2536 induces eryptosis. We used flow cytometry to access death in red blood cells. We analyzed the cellular volume, the intracellular calcium concentration, the cell surface phosphatidylserine exposure, and the ceramide abundance. In addition, we analyzed the effect of BI2536 on hemolysis. Our investigation showed that after 48 h of incubation with PLK inhibitor BI2536, erythrocytes lost volume and were positive for annexin­V without any effect on hemolysis. Cells also showed an abundance of ceramide and an increase of intracellular calcium. All these finding suggest that BI2536 provokes eryptosis in red blood cells, ostensibly in part due to Ca2+ entry and ceramide accumulation.

Association between interleuleukin-1ß polymorphism (rs16944) and biomarkers levels in Iraqi patients with prostate cancer.

OBJECTIVE: Prostate cancer (PCa) is the second-leading cause of mortality in men and the most commonly diagnosed non-cutaneous male malignancy. Host genetic factors, and inflammation-induced cytokines, play a key role in prostate oncogenesis. Single Nucleotide Polymorphisms (SNP) in cytokine genes were suggested to increase the susceptibility for PCa development and progression. This study aimed to investigate the association between the SNP (rs16944) in the interleukin-1 ß (IL-1ß) gene and the serum levels of Prostate Specific Antigen (PSA) Prolactine (PRL), testosterone, and IL-1ß in Iraqi PCa patients versus healthy controls. METHODS: Taqman Real Time-PCR, was performed to investigate the IL-1ß (rs16944) polymorphism in 100 Iraqi PCa patients and 50 age-matched healthy controls in a case-control study. Serum levels of PSA, PRL, and testosterone were determined by ELISA and FIA, and associated with the IL-1ß serum level as well as with the SNP (rs 16944). The association between the clinico-pathological parameters and the genotype distribution of PCa patients was also studied. RESULTS: There level of IL-1ß was significant increased in the serum of PCa patients compared to controls (P = 8.19 10-7). Serum levels for other biomarkers such as PSA, PRL and testosterone were also significantly elevated in patients compared to controls (P < 0.0001). No differences were seen for genotype and allele distribution between PCa patients and controls. Nevertheless, in the group of controls, we found that 36% carried the GG genotype against only 26% in the patients group.This suggests that this could be a protective genotype (OR 0.62, P = 0.254). In addition, we found that the GA genotype is slightly more frequent in patients as compared to controls (OR 1.22, P = 0.605). Interestingly, serum levels of IL-1ß, PSA, PRL and testosterone were significantly higher in PCa patients carrying the GA genotype, and the GA and AA genotypes are strongly associated with the aggressive behavior of the disease such as advanced TNM, and high Gleason score. CONCLUSION: Our data suggest that both serum IL-1ß level and IL-1ß SNP (rs16944) may be considered as candidate biomarkers for PCa. Moreover, the GA, and AA genotypes carriers along with high sera levels of IL-1ß, PSA and PRL, have an increased risk for PCa with aggressive behavior in Iraqi men.

Predominance of the Rare EGFR Mutation p.L861Q in Tunisian Patients with Non-Small Cell Lung Carcinoma.

Objectives: Several new cancer therapies targeting signaling pathways involved in the growth and progression of cancer cells were developed as personalized medicine. Our study aimed to identify epidermal growth factor receptor (EGFR) mutations for TKI treatment in non-small-cell lung cancer (NSCLC) Tunisian patients. Methods: Analysis of the TKI sensitivity mutations in exons 18 to 21 of the EGFR gene and exon 15 of the B-raf gene was performed in 79 formalin fixed-paraffin embedded (FFPE) NSCLC samples using pyrosequencing. Results: EGFR mutations were detected in 34 cases among 79 (43%), with the predominance of the L861Q in exon 21 found in 35.3% of the cases (12 out of 34). Deletions in exon 19 were found in 8 cases (23.5%), and only one young male patient had the T790M mutation. Three patients harbored composite EGFR mutations (p.E746_A750del/p.L861R, p.E746_S752>V/p.S768I, and p.G719A/p.L861Q). Furthermore, the EGFR mutated status was significantly more frequent in female patients (p = 0.019), in non-smoker patients (p = 0.008), and in patients with metastasis (p = 0.044). Moreover, the B-raf V600E was identified in 5 EGFR negative patients among 39 analyzed samples (13.15%). Conclusion: The p.L861Q localized in exon 21 of the EGFR gene was the most common mutation identified in our patients (35.3%), whereas the "classic" EGFR mutations such as Del19 and p.L858R were found in 23.5% and 11.7% of the cases, respectively. Interestingly, most of p.L861X mutation-carrying patients showed good response to TKI treatment. Altogether, our findings suggest a particular distribution of the EGFR-TKIs sensitivity mutations in Tunisian NSCLC patients.

The Identification by Exome Sequencing of Candidate Genes in BRCA-Negative Tunisian Patients at a High Risk of Hereditary Breast/Ovarian Cancer.

(1) Background: Germline variants in BRCA1/BRCA2 genes explain about 20% of hereditary breast/ovarian cancer (HBOC) cases. In the present paper, we aim to identify genetic determinants in BRCA-negative families from the South of Tunisia. (2) Methods: Exome Sequencing (ES) was performed on the lymphocyte DNA of patients negative for BRCA mutations from each Tunisian family with a high risk of HBOC. (3) Results: We focus on the canonical genes associated with HBOC and identified missense variants in DNA damage response genes, such as ATM, RAD52, and RAD54; however, no variants in PALB2, Chek2, and TP53 genes were found. To identify novel candidate genes, we selected variants harboring a loss of function and identified 17 stop-gain and 11 frameshift variants in genes not commonly known to be predisposed to HBOC. Then, we focus on rare and high-impact genes shared by at least 3 unrelated patients from each family and selected 16 gene variants. Through combined data analysis from MCODE with gene ontology and KEGG pathways, a short list of eight candidate genes (ATM, EP300, LAMA1, LAMC2, TNNI3, MYLK, COL11A2, and LAMB3) was created. The impact of the 24 selected genes on survival was analyzed using the TCGA data resulting in a selection of five candidate genes (EP300, KMT2C, RHPN2, HSPG2, and CCR3) that showed a significant association with survival. (4) Conclusions: We identify novel candidate genes predisposed to HBOC that need to be validated in larger cohorts and investigated by analyzing the co-segregation of selected variants in affected families and the locus-specific loss of heterozygosity to highlight their relevance for HBOC risk.

Development of a simple genotyping method based on indel mutations to rapidly screen SARS-CoV-2 circulating variants: Delta, Omicron BA.1 and BA.2.

The high need of rapid and flexible tools that facilitate the identification of circulating SARS-CoV-2 Variants of Concern (VOCs) remains crucial for public health system monitoring. Here, we develop allele-specific (AS)-qPCR assays targeting three recurrent indel mutations, ΔEF156-157, Ins214EPE and ΔLPP24-26, in spike (S) gene to identify the Delta VOC and the Omicron sublineages BA.1 and BA.2, respectively. After verification of the analytical specificity of each primer set, two duplex qPCR assays with melting curve analysis were performed to screen 129 COVID-19 cases confirmed between December 31, 2021 and February 01, 2022 in Sfax, Tunisia. The first duplex assay targeting ΔEF156-157 and Ins214EPE mutations successfully detected the Delta VOC in 39 cases and Omicron BA.1 in 83 cases. All the remaining cases (n = 7) were identified as Omicron BA.2, by the second duplex assay targeting Ins214EPE and ΔLPP24-26 mutations. The results of the screening method were in perfect concordance with those of S gene partial sequencing. In conclusion, our findings provide a simple and flexible screening method for more rapid and reliable monitoring of circulating VOCs. We highly recommend its implementation to guide public health policies.

Whole and Purified Aqueous Extracts of Nigella sativa L. Seeds Attenuate Apoptosis and the Overproduction of Reactive Oxygen Species Triggered by p53 Over-Expression in the Yeast Saccharomyces cerevisiae.

Plants are an important source of pharmacologically active compounds. In the present work, we characterize the impact of black cumin (Nigella sativa L.) aqueous extracts on a yeast model of p53-dependent apoptosis. To this end, the Saccharomyces cerevisiae recombinant strain over-expressing p53 was used. The over-expression of p53 triggers the expression of apoptotic markers: the externalization of phosphatidylserine, mitochondrial defect associated with cytochrome-c release and the induction of DNA strand breaks. These different effects were attenuated by Nigella sativa L. aqueous extracts, whereas these extracts have no effect on the level of p53 expression. Thus, we focus on the anti-apoptotic molecules present in the aqueous extract of Nigella sativa L. These extracts were purified and characterized by complementary chromatographic methods. Specific fluorescent probes were used to determine the effect of the extracts on yeast apoptosis. Yeast cells over-expressing p53 decrease in relative size and have lower mitochondrial content. The decrease in cell size was proportional to the decrease in mitochondrial content and of mitochondrial membrane potential (ΔΨm). These effects were prevented by the purified aqueous fraction obtained by fractionation with different columns, named C4 fraction. Yeast cell death was also characterized by reactive oxygen species (ROS) overproduction. In the presence of the C4 fraction, ROS overproduction was strongly reduced. We also noted that the C4 fraction promotes the cell growth of control yeast cells, which do not express p53, supporting the fact that this purified extract acts on cellular mediators activating cell proliferation independently of p53. Altogether, our data obtained on yeast cells over-expressing p53 demonstrate that anti-apoptotic molecules targeting p53-induced apoptosis associated with mitochondrial dysfunction and ROS overproduction are present in the aqueous extracts of Nigella seeds and in the purified aqueous C4 fraction.

Lower p66Shc promoter methylation in subjects with chronic renal failure.

OBJECTIVE: To determine the correlation between DNA methylation of p66Shc promoter and some markers of inflammatory and oxidative stress in chronic renal failure (CRF) patients compared with healthy subjects. METHODS: An observational cross-sectional study was conducted in the nephrology department at Sidi Bouzid Regional Hospital (Tunisia). In total, 39 patients with CRF and 37 healthy subjects were included. Several biochemical parameters were measured. Furthermore, markers of the oxidative and inflammatory status (MDA, TAS, SOD, and CRP) were evaluated. The p66Shc methylation status was determined using the methylation-specific PCR. RESULTS: Our results showed that levels of blood glucose, urea, creatinine, uric acid, ChT, TG, albuminuria, CRP and MDA were significantly elevated in CRF patients compared to controls. Furthermore, p66Shc promoter region was highly demethylated in CRF patients compared to healthy controls (84% vs 4%). Our data showed a positive correlation between p66Shc hypomethylation and levels of MDA (r = 0.93; p<0, 05) and CRP (r = 0.89; P <0, 05), as well as a significant negative correlation between p66Shc hypomethylation, TAS (r = -0.76; P <0, 05) and SOD (r = -0.77; p<0, 05) levels. Similarly, there was a positive correlation between p66Shc hypomethylation and the disease stages. Importantly, multiple regression analysis showed that p66shc DNA hypomethylation remains strongly correlated with MDA, CRP and stages of CRF. CONCLUSION: This study indicates that the DNA hypomethylation of p66shc promoter was correlated with oxidative and inflammatory stress and the disease stages in CRF patients.

Establishment of primary cell culture of Ruditapes decussatus haemocytes for metal toxicity assessment.

In ecotoxicology, in vitro testing on cell cultures represents an ideal alternative to in vivo strategies for emerging contaminants. These tests have limited use particularly with marine invertebrates like the clams Ruditapes decussatus. In the present study, a primary culture of R. decussatus haemocytes was realized for the first time in order to determine the effect of metals (copper, zinc, and cobalt) on haemocyte parameters like viability and phagocytosis. Results showed that (i) among the studied medium, the modified Leibovitz (L-15) is the best for R. decussatus haemocytes primary culture. (ii) The primary culture system used here represents a suitable in vitro model for assessing cytotoxic responses, (iii) a decrease of cell viability and phagocytosis after 24 h exposure to 100 µg mL-1 CoSO4 and an increase of phagocytosis after 24 h exposure to 50 µg mL-1CuSO4.

Novel and recurrent BRCA1/BRCA2 germline mutations in patients with breast/ovarian cancer: a series from the south of Tunisia.

BACKGROUND: The incidence of breast cancer (BC) and/or ovarian cancer (OC) is increasing in Tunisia especially in young women and mostly those with family history. However, the spectrum of BRCA mutations remains little explored in Tunisian patients in particular in the southern region. METHODS: We sequenced the entire coding regions of BRCA1and BRCA2 genes using next generation sequencing (NGS) in 134 selected patients with BC and/or OC. RESULTS: Among the 134 patients, 19 (14.17%) carried pathogenic mutations (10 are BRCA1 mutation carriers and 9 are BRCA2 mutation carriers) that are mainly frameshift index (76.9%). Interestingly, 5 out of the 13 variants (38.46%) were found at least twice in unrelated patients, as the c.1310-1313 delAAGA in BRCA2 and the c.5030_5033 delCTAA that has been identified in 4/98 BC patients and in 3/15 OC patients from unrelated families with strong history of cancer. Besides recurrent mutations, 6 variant (4 in BRCA1 and 2 in BRCA2) were not reported previously. Furthermore, 3 unrelated patients carried the VUS c.9976A > T, (K3326*) in BRCA2 exon 27. BRCA carriers correlated significantly with tumor site (p = 0.029) and TNBC cases (p = 0.008). In the groups of patients aged between 31 and 40, and 41-50 years, BRCA1 mutations occurred more frequently in patients with OC than those with BC, and conversely BRCA2 carriers are mostly affected with BC (p = 0.001, and p = 0.044 respectively). CONCLUSIONS: The overall frequency of the BRCA germline mutations was 14.17% in patients with high risk of breast/ovarian cancer. We identified recurrent mutations as the c.1310_1313 delAAGA in BRCA2 gene and the c.5030_5033 delCTAA in BRCA1 gene that were found in 4% and 20% of familial BC and OC respectively. Our data will contribute in the implementation of genetic counseling and testing for families with high-risk of BC and/or OC.

Identification of novel candidate genes by exome sequencing in Tunisian familial male breast cancer patients.

Male Breast Cancer (MBC) is a rare and aggressive disease that is associated with genetic factors. Mutations in BRCA1 and BRCA2 account for 10% of all MBC cases suggesting that other genetic factors are involved. The aim of the present study is to screen whole BRCA1 and BRCA2 exons using the Ampliseq BRCA panel in Tunisian MBC patients with family history. Furthermore, we performed exome sequencing using the TruSight One sequencing panel on an early onset BRCA negative patient. We showed that among the 6 MBC patients, only one (MBC-F1) harbored a novel frameshift mutation in exon 2 of the BRCA2 gene (c.17-20delAAGA, p.Lys6Xfs) resulting in a short BRCA2 protein of only 6 amino-acids. We selected 9 rare variants after applying several filter steps on the exome sequencing data. Among these variants, and based on their role in breast carcinogenesis, we retained 6 candidate genes (MSH5, DCC, ERBB3, NOTCH3, DIAPH1, and DNAH11). Further studies are needed to confirm the association of the selected genes with family MBC.

FOXA1 Expression in Nasopharyngeal Carcinoma: Association with Clinicopathological Characteristics and EMT Markers.

The forkhead box (FOXA) family of transcription factors regulates gene expression and chromatin structure during tumorigenesis and embryonic development. Until now, the relationship between FOXA1 and the nasopharyngeal carcinoma (NPC) has not yet been reported. Therefore, our purpose is to analyze the expression of FOXA1 in 56 NPC patients compared to 10 normal nasopharyngeal mucosae and to correlate the expression with the clinicopathological features. Besides, we investigated the association between FOXA1 and LMP1 gene expression, as well as the EMT markers namely the E-cadherin and Twist1. Among 56 NPC tissues, 34 (60.7%) cases were positive for FOXA1. Furthermore, we noticed that FOXA1 expression correlated with TNM (p = 0.037), and age at diagnosis (p = 0.05). Moreover, positive expression of FOXA1 is likely to be associated with prolonged disease-free survival and overall survival rates. On the other hand, we observed a positive association between the expression of E-cadherin and FOXA1 (p = 0.0051) whereas Twist1 correlated negatively with FOXA1 (p = 0.004). Furthermore, knowing that LMP1 plays a key role in the pathogenesis of NPC, we explored the association of FOXA1 with the LMP1 gene expression in both NPC cell lines and tissues. We found that, in the C666-1 which displays low levels of LMP1, the expression of FOXA1 is high, and inversely in the C15 cell line that expresses a high level of LMP1, the level of FOXA1 is low. Besides, in accordance to our results, we found that in NPC tissues there is a negative association between LMP1 and FOXA1. In conclusion, our results suggest that the overexpression of FOXA1 is associated with a nonaggressive behavior and favorable prognosis in NPC patients. FOXA1 could contribute in the EMT process through key factors as E-cadherin, Twist1, and LMP1.

Serine protease inhibitors and human wellbeing interplay: new insights for old friends.

Serine Protease Inhibitors (Serpins) control tightly regulated physiological processes and their dysfunction is associated to various diseases. Thus, increasing interest is given to these proteins as new therapeutic targets. Several studies provided functional and structural data about human serpins. By comparison, only little knowledge regarding bacterial serpins exists. Through the emergence of metagenomic studies, many bacterial serpins were identified from numerous ecological niches including the human gut microbiota. The origin, distribution and function of these proteins remain to be established. In this report, we shed light on the key role of human and bacterial serpins in health and disease. Moreover, we analyze their function, phylogeny and ecological distribution. This review highlights the potential use of bacterial serpins to set out new therapeutic approaches.

Association of FOXA1 and EMT markers (Twist1 and E-cadherin) in breast cancer.

The transcription factor FOXA1 (forkhead box A1) plays key roles in tumor development and progression. In the present study, we analyzed the expression of FOXA1 in 52 breast tumors and 10 normal tissues, and investigated the relationship between FOXA1 and two EMT markers, namely Twist1 and E-cadherin by RT-PCR and IHC respectively. The expression level of FOXA1 was higher in tumor compared to normal tissues but the difference was not statistically significant (P = 0.138). FOXA1 expression correlated with less aggressive behavior as SBR grade I (P = 0.04), small tumors size (P = 0.05), and longer survival (P = 0.001). Furthermore, estrogen and progesterone positive tumors exhibit high level of FOXA1 (P = 0.002 and P = 0.038 respectively). Survival analysis showed that patients with ER positive/FOXA1 positive (P log rank = 0.001), PR positive/FOXA1 positive (P log rank = 0.044) and HER-2 negative/FOXA1 positive (P log rank = 0.002) tumors have a significant prolonged overall survival. On the other hand, the expression of E-cadherin positively correlated with FOXA1 (P = 0.028), whereas negative association was seen between the expression of Twist1 and FOXA1 (P = 0.016). Kaplan-Meier plots showed that patients with Twist1negative/FOXA1positive tumors have a significant prolonged overall survival (P log rank = 0.001) and FOXA1 appeared as independent predictors of patient survival in multivariate analyses. Overall, our results indicate that FOXA1 could be a useful biomarker to predict prognosis in breast cancer patients.

B1.12: a novel peptide interacting with the extracellular loop of the EBV oncoprotein LMP1.

Latent membrane protein 1 (LMP1) encoded by the Epstein-Barr virus (EBV) plays an important role in EBV-induced cell transformation. Down-regulation of the LMP1 expression had shown promising results on cancer cell therapy. In this study, we identified by Phage display a novel peptide called B1.12 (ACPLDLRSPCG) which selectively binds to the extracellular loop (B1) of the LMP1 oncoprotein as demonstrated by molecular docking, NMR and ITC. Using an LMP1 expressing cell line, we showed that B1.12 decreased cell viability, and induced G0/G1 cell cycle arrest. In addition, the expression of A20, pAkt, and pNFkb (pRelA536) in C666-1 cells treated with B1.12 decreased compared to the untreated cells. In conclusion, we selected a novel peptide able to bind specifically to the extracellular loop of LMP1 and thus modulate its oncogenic properties.

Expression and role of nuclear receptor coregulators in colorectal cancer.

Colorectal cancer (CRC) is one of the most common human cancers and the cause of about 700000 deaths per year worldwide. Deregulation of the WNT/ß-catenin pathway is a key event in CRC initiation. This pathway interacts with other nuclear signaling pathways, including members of the nuclear receptor superfamily and their transcription coregulators. In this review, we provide an overview of the literature dealing with the main coactivators (NCoA-1 to 3, NCoA-6, PGC1-α, p300, CREBBP and MED1) and corepressors (N-CoR1 and 2, NRIP1 and MTA1) of nuclear receptors and summarize their links with the WNT/ß-catenin signaling cascade, their expression in CRC and their role in intestinal physiopathology.

New Phage Display-Isolated Heptapeptide Recognizing the Regulatory Carboxy-Terminal Domain of Human Tumour Protein p53.

The transcription factor tumor protein p53 (P53) controls a variety of genes most involved in cell cycle and is at the origin of apoptosis when DNA is irreparably damaged. We planned to select novel tumor protein p53-interacting peptides through the screening of hepta-peptide phage-display libraries. For this aim, human tumor suppressor protein p53 was expressed in Escherichia coli as Glutathione S-transferase fusion and purified by affinity chromatography. The phage library was then screened on this immobilized protein target. After three rounds of panning, phages were sequenced and shown to contain a consensus sequence NPNSAQG. Thereafter, either free p53 liberated from the fusion protein through thrombin treatment or Histidine-tagged p53 were recognized efficiently by the selected phage. To locate the p53-binding epitope of the selected hepta-peptide, three long peptides parts of the three known domains of the protein were synthesized and screened by the selected phage/peptide. Thus, the Carboxy-terminal p53 region was shown to be the target of the isolated phage as well as by its derived Fluorescein isothiocyanate-peptide. Molecular docking showed Lysine 386 as an important residue potentially engaged in this interaction. The selected hepta-peptide is a novel p53-interacting peptide, not described by other studies, and could be used as therapeutic tool in the future.

Clinical and prognosis value of the CIMP status combined with MLH1 or p16 INK4a methylation in colorectal cancer.

Aberrant DNA methylation of CpG islands occurred frequently in CRC and associated with transcriptional silencing of key genes. In this study, the CIMP combined with MLH1 or p16 INK4a methylation status was determined in CRC patients and correlated with clinicopathological parameters and overall survival. Our data showed that CIMP+ CRCs were identified in 32.9% of cases and that CACNAG1 is the most frequently methylated promoter. When we combined the CIMP with the MLH1 or the p16 INK4a methylation status, we found that CIMP-/MLH1-U (37.8%) and CIMP-/p16 INK4a -U (35.4%) tumors were the most frequent among the four subtypes. Statistical analysis showed that tumor location, lymphovascular invasion, TNM stage, and MSI differed among the group of patients. Kaplan-Meier analyses revealed differences in overall survival according to the CIMP combined with MLH1 or p16 INK4a methylation status. In a multivariate analysis, CIMP/MLH1 and CIMP/p16 INK4a methylation statuses were predictive of prognosis, and the OS was longer for patients with tumors CIMP-/MLH1-M, as well as CIMP-/p16 INK4a -M. Furthermore, DNMT1 is significantly overexpressed in tumors than in normal tissues as well as in CIMP+ than CIMP- tumors. Our results suggest that tumor classification based on the CIMP status combined with MLH1 or p16 INK4a methylation is useful to predict prognosis in CRC patients.

Overexpression of miR-10b in colorectal cancer patients: Correlation with TWIST-1 and E-cadherin expression.

MicroRNAs are emergent players of epigenetics that function as oncogenes or tumor suppressors and that have been implicated in regulating diverse cellular pathways. MiR-10b is an oncogenic microRNA involved in tumor invasion and metastasis in various cancers. Our data have shown that miR-10b is overexpressed in colorectal cancer samples in comparison with non-tumorous adjacent mucosa (p = 0.0025) and that it is associated with severe features such as tumor size >5 cm (p = 0.023), distant metastasis (p = 0.0022), non-differentiated tumors (p = 0.016), and vascular invasion (p = 0.01). Regarding the regulation of its expression, positive correlation between the loss of miR-10b and aberrant DNA methylation (p = 0.02) as well as a loss of TWIST-1 messenger RNA (p = 0.018) have been observed. Furthermore, expression analysis of the downstream miR-10b targets has shown that there are associations between low HOXD10 messenger RNA and E-cadherin protein levels (p < 0.0001, p = 0.0008, respectively) and overexpression of miR-10b. Our data suggests that overexpression of miR-10b results from high levels of TWIST-1 and may induce a decrease of E-cadherin membranous protein levels, thus contributing to the acquisition of metastatic phenotypes in colorectal cancer.

RIP140 and LCoR expression in gastrointestinal cancers.

The transcription coregulators RIP140 and LCoR are part of a same complex which controls the activity of various transcription factors and cancer cell proliferation. In this study, we have investigated the expression of these two genes in human colorectal and gastric cancers by immunohistochemistry. In both types of tumors, the levels of RIP140 and LCoR appeared highly correlated. Their expression tended to decrease in colorectal cancer as compared to adjacent normal tissues but was found higher in gastric cancer as compared to normal stomach. RIP140 and LCoR expression correlated with TNM and tumor differentiation. Significant correlations were observed with expression levels of key proteins involved in tumor progression and invasion namely E-cadherin and Cyclooxygenase-2. Survival analysis showed that patients with LCoRlow/RIP140high colorectal tumors have a significant prolonged overall and disease-free survival. In gastric cancer, high LCoR expression was identified as an independent marker of poor prognosis suggesting a key role in this malignancy. Altogether, these results demonstrate that RIP140 and LCoR have a prognostic relevance in gastrointestinal cancers and could represent new potential biomarkers in these tumors.