Validation of miR-31-3p Expression to Predict Cetuximab Efficacy When Used as First-Line Treatment in RAS Wild-Type Metastatic Colorectal Cancer.

PURPOSE: MiR-31-3p expression has been shown to be associated with response to anti-EGFR therapy. We investigated the predictive role of this biomarker in the FIRE-3 study population, including its ability to differentiate outcomes between patients receiving anti-EGFR and anti-VEGF therapy. EXPERIMENTAL DESIGN: MiR-31-3p expression was measured in primary tumors obtained from 340 patients with RAS WT mCRC enrolled in the FIRE-3 Trial. This included 164 patients randomized to receive FOLFIRI plus cetuximab (FOLFIRI+Cetux) and 176 to FOLFIRI plus bevacizumab (FOLFIRI+Beva). Patients were divided into subgroups defined by low or high miR-31-3p expression using a prespecified cut-off and by treatment arm. Analyses were performed to assess treatment efficacy by subgroup. Overall survival (OS) and progression-free survival (PFS) were analyzed using Kaplan-Meier curves and Cox regression models. Investigator-assessed objective response (iOR), early tumor shrinkage at 6 weeks (ETS), and centrally reviewed objective response (cOR) were analyzed using logistic regression models. The predictive value of miR-31-3p expression level was assessed through a treatment interaction test using multivariate models adjusted for potential confounding factors. RESULTS: Low miR-31-3p expressers benefited from cetuximab compared with bevacizumab for PFS [HR, 0.74; 95% confidence interval (CI), 0.55-1.00; P = 0.05], OS (HR, 0.61; 95% CI, 0.41-0.88; P < 0.01), iOR (OR, 4.0; 95% CI, 1.9-8.2; P < 0.01), ETS (OR, 4.0; 95% CI, 2.1-7.7; P < 0.01 and cOR (OR, 4.9; 95% CI, 2.3-10.5; P < 0.01) in multivariate analyses. There was no difference in outcomes for high expressers between treatment arms. MiR-31-3p expression level was predictive of treatment effect for PFS (P = 0.03), OS (P = 0.05), iOR (P = 0.02), ETS (P = 0.04), and cOR (P < 0.01). CONCLUSIONS: MiR-31-3p expression level was validated as a predictive biomarker of cetuximab therapy efficacy for patients with RAS WT mCRC.

Technical Validation of a Reverse-Transcription Quantitative Polymerase Chain Reaction In Vitro Diagnostic Test for the Determination of MiR-31-3p Expression Levels in Formalin-Fixed Paraffin-Embedded Metastatic Colorectal Cancer Tumor Specimens.

MiR-31-3p expression has been shown to be a predictive biomarker for response to anti-epithelial growth factor receptor therapy in patients with RAS wild-type metastatic colorectal cancer (mCRC). To aid in the quantification of miR-31-3p expression in formalin-fixed paraffin-embedded (FFPE) primary tumor samples from patients with mCRC, a reverse-transcription quantitative polymerase chain reaction (RT-qPCR) assay was developed and validated. Assay development included the identification of a microRNA reference standard and the determination of an appropriate relative quantification cutoff for differentiating low versus high miR-31-3p expression. Sample specimens for the validation studies included both FFPE slides and shavings. Polymerase chain reaction (PCR) efficiency and linearity, analytical sensitivity and specificity, assay robustness, reproducibility, and accuracy were demonstrated across a number of test conditions and differing quantitative PCR platforms. The data from this study provide evidence as to the feasibility of quantifying the expression of miR-31-3p from FFPE tumor tissue using a standardized RT-qPCR assay.

Association between miR-31-3p expression and cetuximab efficacy in patients with KRAS wild-type metastatic colorectal cancer: a post-hoc analysis of the New EPOC trial.

BACKGROUND: High miR-31-3p expression is associated with inferior outcomes in KRAS wild-type (WT) advanced colorectal cancer patients treated with anti-EGFR therapy. This study evaluated miR-31-3p expression in patients with operable colorectal liver metastases (LM) enrolled in the New EPOC study. METHODS: MiR-31-3p expression was measured in primary tumors (PT) from 149 KRAS WT patients including 71 receiving chemotherapy alone (CT) and 78 receiving chemotherapy plus cetuximab (CTX). Each treatment arm was split into tertiles based on miR-31-3p expression levels. MiR-31-3p expression was also measured in LM from 94 patients with tumor tissue available. RESULTS: The median progression-free survival for the combined populations with mid or high miR-31-3p expression was shorter in the CTX versus the CT arm (26.7 months versus 12.3 months, HR=2.28 95%CI 1.27; 4.09 p=0.006). Low miR-31-3p expressers had similar outcomes irrespective of treatment (HR=1.06 95%CI 0.43; 2.61 p=0.9). MiR-31-3p expression was correlated between paired PT and LM samples in the CT group but not in the CTX group. CONCLUSIONS: Patients with low miR-31-3p expression in the New EPOC study were not harmed by the addition of cetuximab. This supports miR-31-3p as a promising predictive biomarker for anti-EGFR therapy in KRAS WT advanced colorectal cancer.

Characterization and Genetic Analyses of New Genes Coding for NOD2 Interacting Proteins.

NOD2 contributes to the innate immune response and to the homeostasis of the intestinal mucosa. In response to its bacterial ligand, NOD2 interacts with RICK and activates the NF-κB and MAPK pathways, inducing gene transcription and synthesis of proteins required to initiate a balanced immune response. Mutations in NOD2 have been associated with an increased risk of Crohn's Disease (CD), a disabling inflammatory bowel disease (IBD). Because NOD2 signaling plays a key role in CD, it is important to further characterize the network of protein interacting with NOD2. Using yeast two hybrid (Y2H) screens, we identified new NOD2 interacting proteins (NIP). The primary interaction was confirmed by coimmunoprecipitation and/or bioluminescence resonance energy transfer (BRET) experiments for 11 of these proteins (ANKHD1, CHMP5, SDCCAG3, TRIM41, LDOC1, PPP1R12C, DOCK7, VIM, KRT15, PPP2R3B, and C10Orf67). These proteins are involved in diverse functions, including endosomal sorting complexes required for transport (ESCRT), cytoskeletal architecture and signaling regulation. Additionally, we show that the interaction of 8 NIPs is compromised with the 3 main CD associated NOD2 mutants (R702W, G908R and 1007fs). Furthermore, to determine whether these NOD2 protein partners could be encoded by IBD susceptibility genes, a transmission disequilibrium test (TDT) was performed on 101 single nucleotide polymorphisms (SNPs) and the main corresponding haplotypes in genes coding for 15 NIPs using a set of 343 IBD families with 556 patients. Overall this work did not increase the number of IBD susceptibility genes but extends the NOD2 protein interaction network and suggests that NOD2 interactome and signaling depend upon the NOD2 mutation profile in CD.

Hsa-miR-31-3p expression is linked to progression-free survival in patients with KRAS wild-type metastatic colorectal cancer treated with anti-EGFR therapy.

PURPOSE: To identify microRNAs (miRNA) that predict response to anti-EGFR antibodies in patients with wild-type KRAS metastatic colorectal cancer (mCRC). EXPERIMENTAL DESIGN: miRNA profiling was performed in a training set of 87 patients with mCRC refractory to chemotherapy treated with anti-EGFR antibodies. This included 33 fresh-frozen (FF) and 35 formalin-fixed paraffin-embedded (FFPE) samples retrospectively collected and 19 prospectively collected FF samples. An independent validation cohort consisting of 19 FF and 26 FFPE prospectively collected samples from patients with mCRC treated with anti-EGFR antibodies was used to confirm our findings. RESULTS: After screening the expression of 1,145 miRNAs in FF samples from the training set, we identified that hsa-miR-31-3p expression level was significantly associated with progression-free survival (PFS). Statistical models based on miRNA expression discriminated between high and low risk of progression for both FF and FFPE samples. These models were confirmed in the validation cohort for both FF [HR, 4.1; 95% confidence interval (CI), 1.1-15.3; P < 0.04] and FFPE samples (HR, 2.44; 95% CI, 1.1-5.4; P = 0.028). The percentage of variation of RECIST criteria in the validation series was significantly associated with the expression level of hsa-miR-31-3p (r(2) = 0.49; P = 0.0035) and risk status determined by hsa-miR-31-3p expression level (P = 0.02, Kruskal-Wallis rank test). Nomograms were built and validated to predict PFS-depending on hsa-miR-31-3p expression level. Following in vitro studies, we identified 47 genes regulated by hsa-miR-31-3p. CONCLUSION: Hsa-miR-31-3p seems to be a new mCRC biomarker whose expression level allows for the identification of patients with wild-type KRAS mCRC who are more likely to respond to anti-EGFR therapy.

Analysis of single nucleotide polymorphisms in the region of CLDN2-MORC4 in relation to inflammatory bowel disease.

AIM: To investigate a possible genetic influence of claudin (CLDN)1, CLDN2 and CLDN4 in the etiology of inflammatory bowel disease. METHODS: Allelic association between genetic regions of CLDN1, CLDN2 or CLDN4 and patients with inflammatory bowel disease, Crohn's disease (CD) or ulcerative colitis were investigated using both a case-control study approach (one case randomly selected from each of 191 Swedish inflammatory bowel disease families and 333 controls) and a family-based study (463 non-Swedish European inflammatory bowel disease -families). A nonsynonymous coding single nucleotide polymorphism in MORC4, located on the same linkage block as CLDN2, was investigated for association, as were two novel CLDN2 single nucleotide polymorphism markers, identified by resequencing. RESULTS: A single nucleotide polymorphism marker (rs12014762) located in the genetic region of CLDN2 was significantly associated to CD (case-control allelic OR = 1.98, 95%CI: 1.17-3.35, P = 0.007). MORC4 was present on the same linkage block as this CD marker. Using the case-control approach, a significant association (case control allelic OR = 1.61, 95%CI: 1.08-2.41, P = 0.018) was found between CD and a nonsynonymous coding single nucleotide polymorphism (rs6622126) in MORC4. The association between the CLDN2 marker and CD was not replicated in the family-based study. Ulcerative colitis was not associated to any of the single nucleotide polymorphism markers. CONCLUSION: These findings suggest that a variant of the CLDN2-MORC4 region predisposes to CD in a Swedish population.

Yersinia pseudotuberculosis disrupts intestinal barrier integrity through hematopoietic TLR-2 signaling.

Intestinal barrier function requires intricate cooperation between intestinal epithelial cells and immune cells. Enteropathogens are able to invade the intestinal lymphoid tissue known as Peyer's patches (PPs) and disrupt the integrity of the intestinal barrier. However, the underlying molecular mechanisms of this process are poorly understood. In mice infected with Yersinia pseudotuberculosis, we found that PP barrier dysfunction is dependent on the Yersinia virulence plasmid and the expression of TLR-2 by hematopoietic cells, but not by intestinal epithelial cells. Upon TLR-2 stimulation, Y. pseudotuberculosis-infected monocytes activated caspase-1 and produced IL-1ß. In turn, IL-1ß increased NF-κB and myosin light chain kinase activation in intestinal epithelial cells, thus disrupting the intestinal barrier by opening the tight junctions. Therefore, Y. pseudotuberculosis subverts intestinal barrier function by altering the interplay between immune and epithelial cells during infection.