Wnt signaling is essential for tissue homeostasis and its dysregulation causes cancer. Wnt ligands trigger signaling by activating Frizzled receptors (FZDRs), which belong to the G-protein coupled receptor superfamily. However, the mechanisms of G protein activation in Wnt signaling remain controversial. In this study, we demonstrate that FZDRs activate G proteins and trigger non-canonical Wnt signaling via the Dishevelled-binding protein, Daple. Daple contains a Gα-binding and activating (GBA) motif, which activates Gαi proteins and an adjacent domain that directly binds FZDRs, thereby linking Wnt stimulation to G protein activation. This triggers non-canonical Wnt responses, that is, suppresses the β-catenin/TCF/LEF pathway and tumorigenesis, but enhances PI3K-Akt and Rac1 signals and tumor cell invasiveness. In colorectal cancers, Daple is suppressed during adenoma-to-carcinoma transformation and expressed later in metastasized tumor cells. Thus, Daple activates Gαi and enhances non-canonical Wnt signaling by FZDRs, and its dysregulation can impact both tumor initiation and progression to metastasis.DOI: http://dx.doi.org/10.7554/eLife.07091.001

Although fibroblast heterogeneity is recognized in primary tumors, both its characterization in and its impact on metastases remain unknown. Here, combining flow cytometry, immunohistochemistry and RNA-sequencing on breast cancer samples, we identify four Cancer-Associated Fibroblast (CAF) subpopulations in metastatic lymph nodes (LN). Two myofibroblastic subsets, CAF-S1 and CAF-S4, accumulate in LN and correlate with cancer cell invasion. By developing functional assays on primary cultures, we demonstrate that these subsets promote metastasis through distinct functions. While CAF-S1 stimulate cancer cell migration and initiate an epithelial-to-mesenchymal transition through CXCL12 and TGFβ pathways, highly contractile CAF-S4 induce cancer cell invasion in 3-dimensions via NOTCH signaling. Patients with high levels of CAFs, particularly CAF-S4, in LN at diagnosis are prone to develop late distant metastases. Our findings suggest that CAF subset accumulation in LN is a prognostic marker, suggesting that CAF subsets could be examined in axillary LN at diagnosis.

Summary The colon is primarily responsible for absorbing fluids. It contains a large number of microorganisms including fungi, which are enriched in its distal segment. The colonic mucosa must therefore tightly regulate fluid influx to control absorption of fungal metabolites, which can be toxic to epithelial cells and lead to barrier dysfunction. How this is achieved remains unknown. Here, we describe a mechanism by which the innate immune system allows rapid quality check of absorbed fluids to avoid intoxication of colonocytes. This mechanism relies on a population of distal colon macrophages that are equipped with “balloon-like” protrusions (BLPs) inserted in the epithelium, which sample absorbed fluids. In the absence of macrophages or BLPs, epithelial cells keep absorbing fluids containing fungal products, leading to their death and subsequent loss of epithelial barrier integrity. These results reveal an unexpected and essential role of macrophages in the maintenance of colon-microbiota interactions in homeostasis. Video Abstract

Metastatic colorectal cancer (mCRC) relies on the detachment of aggressive malignant cells from the primary tumor into the bloodstream and, concordantly, the presence of these Circulating Tumor Cells (CTC) is associated with a poor prognosis. In this work, the molecular characterization of CTC from mCRC patients was approached, with the aim of understanding their biology and improving their clinical utility in the management of colorectal cancer patients. For this, EpCAM-based immunoisolation of CTC was combined with whole transcriptome amplification and hybridization onto cDNA microarrays. Gene expression data from mCRC patients, once the background of unspecific immunoisolation from a group of controls had been subtracted, resulted in 410 genes that characterized the CTC population. Bioinformatics were used for the biological interpretation of the data, revealing that CTC are characterized by genes related to cell movement and adhesion, cell death and proliferation, and cell signalling and interaction. RTqPCR on an independent series of mCRC patients and controls was used for the validation of a number of genes related to the main cellular functions characterizing the CTC population. Comparison between primary carcinomas and lung and liver metastases further involved the CTC-genes in the promotion of metastasis. Moreover, the correlation of CTC-gene expression with clinical parameters demonstrated detection and prognosis significance. In conclusion, the molecular characterization of CTC from mCRC patients and the identification of diagnostic and prognostic biomarkers represent an innovative and promising approach in the clinical management of this type of patients.

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Circulating tumor cells (CTCs), proposed as major players in cancer dissemination, have demonstrated clinical prognostic significance in several cancer types. However, their predictive value remains unclear. Here we evaluated the clinical utility of six CTC markers (tissue specific and epithelial to mesenchymal transition transcripts) both as prognostic and predictive tools in metastatic colorectal cancer (mCRC) patients. CTCs were immunoisolated from blood in 50 mCRC patients at baseline and at 4 and 16 weeks after treatment onset. Expression levels of GAPDH, VIL1, CLU, TIMP1, LOXL3 and ZEB2 were determined by qualitative polymerase chain reaction and normalized to the unspecific cell isolation marker CD45. At baseline, median progression-free survival (PFS) and overall survival (OS) for patients with high CTC markers were 6.3 and 12.7 months, respectively, versus 12.7 and 24.2 for patients with low CTC markers (PFS; p 5 0.0003; OS; p 5 0.044). Concerning response to therapy, PFS and OS for patients with increased CTC markers along treatment were, respectively, 6.6 and 13.1 months, compared with 12.7 and 24.3 for patients presenting CTC markers reduction (PFS; p 5 0.004; OS; p 5 0.007). Of note, CTC markers identified therapy-refractory patients not detected by standard image techniques. Patients with increased CTC markers along treatment, but classified as responders by computed tomography, showed significantly shorter survival times (PFS: 7.8 vs. 13.2; OS: 14.4 vs. 24.4; months). In conclusion, we have generated a CTC marker panel for prognosis evaluation and the identification of patients benefiting or not from therapy in mCRC. Our methodology efficiently classified patients earlier than routine computed tomography and from a minimally invasive liquid biopsy.Colorectal cancer (CRC) represents the fourth leading cancer-related death cause worldwide, with appearance of metastasis being associated with a dramatic drop in survival rates.1 In this regard, clinical evidences accrued in the last years demonstrated a principal role for circulating tumor cells (CTCs) dissemination from primary tumors in the generation of distant metastases.2 Concordantly, CTC detection and quantification has shown to be a prognostic factor in different tumor types including CRC, which is the reason why the American Food and Drug Administration (FDA) has given clearance to CellSearch V R system (Veridex) for CTC enumeration in metastatic colorectal cancer (mCRC). Using this platform, it has been reported that the presence of 3 or more CTCs per 7.5 mL of blood in mCRC patients predicted poor patient outcome at baseline, e.g., before treatment.3,4 Apart from the CellSearch V R system, other approaches like density gradient centrifugation, 5 filtration 6 or the more recent inertial focusing separation 7 or dean flow fractionation 8 methods, have been proposed as alternatives for CTC isolation from blood. Coupling CTC isolation with gene expression analyses allowed CTC quantification and molecular characterization at the same time. Relate...

Endometrial carcinoma (EC) is the most frequent among infiltrating tumors of the female genital tract, with myometrial invasion representing an increase in the rate of recurrences and a decrease in survival. We have previously described ETV5 transcription factor associated with myometrial infiltration in human ECs. In this work, we further investigated ETV5 orchestrating downstream effects to confer the tumor the invasive capabilities needed to disseminate in the early stages of EC dissemination. Molecular profiling evidenced ETV5 having a direct role on epithelial-to-mesenchymal transition (EMT). In particular, ETV5 modulated Zeb1 expression and E-Cadherin repression leading to a complete reorganization of cell --cell and cell --substrate contacts. ETV5-promoted EMT resulted in the acquisition of migratory and invasive capabilities in endometrial cell lines. Furthermore, we identified the lipoma-preferred partner protein as a regulatory partner of ETV5, acting as a sensor for extracellular signals promoting tumor invasion. All together, we propose ETV5-transcriptional regulation of the EMT process through a crosstalk with the tumor surrounding microenvironment, as a principal event initiating EC invasion.

Endometrial cancer is among the three most common cancers in females in industrialized countries. In the majority of cases, the tumor is confined to the uterus at the time of diagnosis and presents a good prognosis. However, after primary surgery, 15% to 20% of these tumors recur and have limited response to systemic therapy. We carried out gene expression profiling of high-risk recurrence endometrial cancers to identify new therapeutic approaches targeting the molecular pathways involved in the acquisition of an aggressive tumor phenotype. A microarray gene-expression analysis on a total of 51 human endometrial carcinomas revealed 77 genes specifically altered in high-risk recurrence tumors (P < 0.001). The bioinformatics analysis of gene-gene interactions and molecular relationships among these genes pointed to a prominent role for TGFb1 signaling in the acquisition of an aggressive phenotype. We further showed that TGF-b1 has a principal role at the initiation of endometrial carcinoma invasion through the promotion of the epithelial to mesenchymal transition that leads to the acquisition of an invasive phenotype in HEC-1A and RL95-2 cells. Impairment of this initial step with SB-431542, a specific TGF-b1 inhibitor, precluded further persistent endometrial carcinoma invasion. In conclusion, we showed that the characterization of the molecular changes associated with the acquisition of an aggressive phenotype represents a realistic strategy for the rational identification and characterization of new potential therapeutic targets in an effort to improve the clinical management and the outcome of high-risk endometrial cancer patients. Mol Cancer Ther; 10(8); 1357-66. '2011 AACR.