Acinar-to-Ductal Metaplasia Induced by Transforming Growth Factor Beta Facilitates KRAS-driven Pancreatic Tumorigenesis.

Background & Aims: Transforming growth factor beta (TGFβ) acts either as a tumor suppressor or as an oncogene, depending on the cellular context and time of activation. TGFβ activates the canonical SMAD pathway through its interaction with the serine/threonine kinase type I and II heterotetrameric receptors. Previous studies investigating TGFβ-mediated signaling in the pancreas relied either on loss-of-function approaches or on ligand overexpression, and its effects on acinar cells have so far remained elusive.

A functional interplay between ZNF217 and estrogen receptor alpha exists in luminal breast cancers.

We aimed at highlighting the role of ZNF217, a Krüppel-like finger protein, in Estrogen Receptor-α (ERα)-positive (ER+) and luminal breast cancers. Here we report for the first time that ZNF217 and ERα proteins bind to each other in both breast cancer cells and breast tumour samples, via the ERα hinge domain and the ZNF217 C-terminal domain. ZNF217 enhances the recruitment of ERα to its estrogen response elements (ERE) and the ERα-dependent transcription of the GREB1 estrogen-regulated gene.

High incidence of mammary intraepithelial neoplasia development in Men1-disrupted murine mammary glands.

Mutations of the MEN1 tumour suppressor gene predispose patients to the development of multiple endocrine neoplasia type 1 (MEN1) syndrome, which is characterized by multiple endocrine tumours, including prolactinomas. The recent findings of the interaction between menin, encoded by the MEN1 gene, and the oestrogen receptor, as well as the observation of rare cases of mammary carcinomas in our heterozygous Men1 mutant mice, led us to investigate a putative tumour suppressor function of the Men1 gene in mouse mammary cells by disrupting the gene in luminal epithelial cells. A significantly higher incidence of mammary intraepithelial neoplasia (MIN) was observed in mutant WapCre-Men1(F/F) mice (51.

Activation of rapid oestrogen signalling in aggressive human breast cancers.

Oestrogen receptors can mediate rapid activation of cytoplasmic signalling cascades by recruiting Src and PI3K. However, the involvement of this pathway in breast cancer remains poorly defined. We have previously shown that methylation of ERα is required for the formation of the ERα/Src/PI3K complex and that ERα is hypermethylated in a subset of breast cancers.

ICOS-ligand expression on plasmacytoid dendritic cells supports breast cancer progression by promoting the accumulation of immunosuppressive CD4+ T cells.

Human breast tumors are infiltrated by memory CD4(+) T cells along with increased numbers of regulatory T cells (Treg) and plasmacytoid dendritic cells (pDC) that facilitate immune escape and correlate with poor prognosis. Here, we report that inducible costimulatory molecule (ICOS), a T cell costimulatory molecule of the CTLA4/PD1/CD28 family, is expressed mostly by tumor-associated Treg in primary breast tumors. A large proportion of these ICOS(+) Treg were Ki67(+) and this evident proliferative expansion was found to rely on interactions with tumor-associated pDC.

Impaired IFN-α production by plasmacytoid dendritic cells favors regulatory T-cell expansion that may contribute to breast cancer progression.

Infiltration and dysfunction of immune cells have been documented in many types of cancers. We previously reported that plasmacytoid dendritic cells (pDC) within primary breast tumors correlate with an unfavorable prognosis for patients. The role of pDC in cancer remains unclear but they have been shown to mediate immune tolerance in other pathophysiologic contexts.

Plasmacytoid dendritic cells infiltrating ovarian cancer are associated with poor prognosis.

Using two different and complementary approaches (flow cytometry and immunohistochemistry) on two independent cohorts of ovarian cancer patients, we found that accumulation of plasmacytoid dendritic cells (pDC) in tumors is associated with early relapse. This deleterious effect of tumor-associated pDC was evident when they are present in cancer epithelium but not in lymphoid aggregates.

Tif1γ suppresses murine pancreatic tumoral transformation by a Smad4-independent pathway.

Transcriptional intermediary factor 1γ (TIF1γ; alias, TRIM33/RFG7/PTC7/ectodermin) belongs to an evolutionarily conserved family of nuclear factors that have been implicated in stem cell pluripotency, embryonic development, and tumor suppression. TIF1γ expression is markedly down-regulated in human pancreatic tumors, and Pdx1-driven Tif1γ inactivation cooperates with the Kras(G12D) oncogene in the mouse pancreas to induce intraductal papillary mucinous neoplasms. In this study, we report that aged Pdx1-Cre; LSL-Kras(G12D); Tif1γ(lox/lox) mice develop pancreatic ductal adenocarcinomas (PDACs), an aggressive and always fatal neoplasm, demonstrating a Tif1γ tumor-suppressive function in the development of pancreatic carcinogenesis.

Prognostic value of the expression of C-Chemokine Receptor 6 and 7 and their ligands in non-metastatic breast cancer.

Background: Chemokines and chemokine receptors are major actors of leukocytes trafficking and some have been shown to play an important role in cancer metastasis. Chemokines CCL19, CCL20 and CCL21 and their receptors CCR6 and CCR7, were assessed as potential biomarkers of metastatic dissemination in primary breast cancer.

Methods: Biomarker expression levels were evaluated using immunohistochemistry on paraffin-embedded tissue sections of breast cancer (n = 207).

Inactivation of TIF1gamma cooperates with Kras to induce cystic tumors of the pancreas.

Inactivation of the Transforming Growth Factor Beta (TGFbeta) tumor suppressor pathway contributes to the progression of Pancreatic Ductal AdenoCarcinoma (PDAC) since it is inactivated in virtually all cases of this malignancy. Genetic lesions inactivating this pathway contribute to pancreatic tumor progression in mouse models. Transcriptional Intermediary Factor 1 gamma (TIF1gamma) has recently been proposed to be involved in TGFbeta signaling, functioning as either a positive or negative regulator of the pathway.

Regulatory T cells recruited through CCL22/CCR4 are selectively activated in lymphoid infiltrates surrounding primary breast tumors and lead to an adverse clinical outcome.

Immunohistochemical analysis of FOXP3 in primary breast tumors showed that a high number of tumor-infiltrating regulatory T cells (Ti-Treg) within lymphoid infiltrates surrounding the tumor was predictive of relapse and death, in contrast to those present within the tumor bed. Ex vivo analysis showed that these tumor-infiltrating FOXP3(+) T cells are typical Treg based on their CD4(+)CD25(high)CD127(low)FOXP3(+) phenotype, their anergic state on in vitro stimulation, and their suppressive functions. These Ti-Treg could be selectively recruited through CCR4 as illustrated by (a) selective blood Treg CCR4 expression and migration to CCR4 ligands, (b) CCR4 down-regulation on Ti-Treg, and (c) correlation between Ti-Treg in lymphoid infiltrates and intratumoral CCL22 expression.

Generation of mice with conditionally activated transforming growth factor beta signaling through the TbetaRI/ALK5 receptor.

We generated a transgenic mouse strain (LSL-TbetaRI(CA)) containing a latent constitutively active TGFbeta type I receptor (TbetaRI/ALK5) by using a knock-in strategy into the X chromosome-linked hypoxanthine phosphoribosyl-transferase (Hprt) locus. Transgene expression, under the control of the ubiquitous CAG (human cytomegalovirus enhancer and chicken beta-actin) promoter, is repressed by a floxed transcriptional "Stop" (LSL, Lox-Stop-Lox). In the presence of cre-recombinase, the "Stop" is excised to allow TbetaRI(CA) transgene expression.

Maternal Tgif is required for vascularization of the embryonic placenta.

The mammalian placenta is the site of exchange of nutrients and waste between mother and embryo. In humans, placental insufficiency can result in intrauterine growth retardation, perinatal death and spontaneous abortion. We show that in C57BL/6J mice a null mutation in the gene encoding the transcriptional corepressor, Tgif, causes placental defects.

Silencing of FLRG, an antagonist of activin, inhibits human breast tumor cell growth.

Activin, a member of the transforming growth factor beta (TGFbeta) superfamily, regulates diverse processes, such as cellular growth and differentiation. There is increasing evidence that TGFbeta and its signaling effectors are key determinants of tumor cell behavior. Loss of sensitivity to TGFbeta-induced growth arrest is an important step toward malignancy.